Pregnant mare, foalings and foals (ECB week 8-12) Flashcards

Question

Should the allantoic and amniotic fluid appearances on US change through pregnancy?

Answer 1

No - should not change significantly in the healthy pregnancy Care though as can alter depending on foetal movements Recheck a few days later if appears different, to see if settled down

Answer 2

Rarely indicated Consider mare's welfare and future breeding options Milk electrolytes essential - must have mature milk Cervical softening Glucocortinoids to mature foal Induction protocol - increase in dystocia Foal often compromised If do it too soon will compromise mare and likely foal too

Answer 3

Due date = 340 days (320-360 days range) Can calculate estimated due date as 25 days (3-4 weeks) before a year after the insemination/service date Some mares will go early, some late

Answer 4

Minimum 4m2 (risk assessment if smaller than this at home) Quiet with minimal disturbance Close monitoring - CCTV Good lighting Warm Deep straw bed Foaling alarms stitched into vulva or tail head (e.g. Sisteck) Biosecurity - esp if on stud farm, as infectious agents in the environment will build up over the foaling season, ensure boxes are throughly cleaned and disinfected with fresh bedding between mares

Answer 5

4-6 weeks prior to due date, so mare is exposed to pathogens at the stud and develops appropriate colostrum Thorough worming and vaccination history Normal management and turnout including exercise

Answer 6

Flu/Tet - worth vaccinating 4-6 weeks prior to parturition to boost colostral antibodies Equip Rotavirus - risk assessment, often will on stud farms as infection level in enviro will build up over the foaling season, single mare at home exposure will be low, many foals will be fine with treatment but expensive and better to prevent, IM vaccine at 8, 9 and 10 months of pregnancy, increases concentration of antibodies in colostrum and gives innate immunity to the foal post foaling Equip EHV 1, 4 - do a risk assessment, will change between single horses vs yard/stud, will not prevent individual animals from aborting due to EHV, but it may reduce the risk of multiple abortions on stud farms due to reducing shedding from latently infected pregnant mares (shed during times of stress), so definitely advise if on stud or if mixing with lots of other horses and horses that will go off competing, vaccinate at months 5, 7 and 9 of gestation

Answer 7

If an unvaccinated horse has been exposed and may be in the incubation period of paralytic EHV, as vaccination has been shown to increase the chance of paralysis in this situation Better to vaccinate in advance, rather than during an outbreak

Answer 8

Consider collecting and storing, as losing all the antibodies and nutrition

Answer 9

Clean udder with warm water and tail/back legs, to reduce pathogens, before going into foaling box

Answer 10

Yes Once pH drops to 7, indicates getting closer to foaling Once 6.5 or below, associated with foaling in the next 24-48hrs But in some mares, the pH will not change at all, so don't read too much into it if pH remains high Need sensitive pH strips, able to detect small changes

Answer 11

Milk electrolytes and pH Blood progestagens

Answer 12

Presentation = relative position of longitudinal axis of the mare and foal, the part of the foal that enters the pelvic canal first e.g. anterior, posterior, transverse Position = relationship of foetal back/head (dorsum) to parts of mare e.g. dorso-sacral, dorso-ilieal Posture = relationship of foetal limbs to foetal body e.g. carpal flexion, neck flexion Normal during early parturition = anterior presentation, dorso-sacral

Answer 13

Build up of coordinated uterine contractions Usually during evening/night (not always) - If fed early on in evening and kept quiet, then early evening may be more likely than middle of night Foetus is moving into correct position Signs are easily confused with colic: - Restless - Digging/pawing/nesting - Unsettled - Lying down, getting up repeatedly - Stretching - Sweating not uncommon Can be for hours, few days Wait for some more activity, then get tail bandage on, clean perineum The end of stage 1 is marked by rupture of the chorioallantoic membrane = large volume of clear yellow fluid (waters breaking) - start the clock!

Answer 14

Must be opened prior to foaling 2-3 weeks before due date Or at the end of stage 1, if not yet done (less controlled situation) Local anaesthetic, blunt scissors with blunt end so don't damage rectum, straight line Restitch in days following foaling

Answer 15

To prevent aspiration of air into the vestibule/vagina, to improve pregnancy rates and reduce early embryonic loss

Answer 16

Once waters have broken Amnion appears within 5 mins of waters breaking Increasingly strong uterine and abdominal contractions Mare may continue to get up and down, rock from side to side, or roll Forceful abdominal straining to allow delivery, may vocalise Foal will progress through with each contraction Often one foot in front of other Increased effort as chest is passed Mare relaxes following hip delivery (fine for foal to remain with hindlegs still in for a bit - this is normal) Monitor placental vessels - pulsing continues Check foal presented correctly - glove and sterile lube, feel for 2 front feet and nose in birth canal, nose might be behind feet at fetlock level (problem if isn't) Monitor for regular progress, watch a clock Ensure amnion not over foal's nose once appears at vulva

Answer 17

Expulsion of the placenta Usually passes in 30 mins to 3 hours Tie placenta up to avoid damage, above hocks Check placenta for any missing pieces once passed, esp non pregnant horn - lie out in F shape (turn inside out and will see lots of microcotyledons, white area in centre on non pregnant horn is where it was abutting the fallopian tube, so can be confident none missing) Go in and find it if any missing

Answer 18

Within 60 mins, as at high risk of toxic metritis-laminitis Encourage to come out if hasn't within 60 mins

Answer 19

1st stage: variable, hours to a few days 2nd stage: ideally 10-20 mins, 20-30 mins ok (>30 mins start getting damage to placenta and risk to foal) 3rd stage: ideally 30 mins - 3hrs, 3-6hrs ok, >6 hours is retained and needs veterinary retention (>1hr if heavy breed)

Answer 20

Rectal gloves Lubrication - lots (normal and J lube) Foaling ropes x 3 in different colours Rope handles (helps to wrap ropes around and make easier to pull) e.g. bits from broom handle Drugs: - Dom/Torb - Buscopan or clenbuterol (Ventipulin) - NSAIDs (for afterwards) - Local anaesthetic (for opening Caslick if needed) - Ketamine? - Adrenaline if need to resurrect foal - Diazepam if seizuring, hypoxic foal - IV fluids for mare or foal Needles and syringes Catheter Stitch kit for catheter Oxygen Stomach tube and pump for infusing into uterus

Answer 21

If uterine perforation is suspected (but won't know this in most cases..)

Answer 22

Tractor to hoist back legs up, or slings to hoist up to roof rafters in stable (gravity pushes foal back into abdomen, to allow you to correct it)

Answer 23

Pull gently but firmly Pull in unison with mare's efforts 'Walk' the legs out (pull one leg, then the other) Lots of lubrication Maximum of 2-3 people pulling (any more than this risk damage) Do not use excessive force - easy to damage cervix, vagina

Answer 24

Put water based lube in bucket of warm water and stomach pump into uterus Or make up J lube into warm water and stomach pump in

Answer 25

Always check time you arrive 1. Put rectal glove on and have a feel, determine if front or back end, presentation, position and posture 2. Make a plan for correction and drugs needed 3. Draw up sedation, buscopan +/- clenbuterol and give to mare 4. Check time again and start attempting correction - put foaling ropes on available limbs, ideally above fetlock, put rope behind ears and through mouth 5. If unsuccessful, move to next stage - more drugs, change mare's position, GA, referral 6. If no progress after 15-20 mins, then serious risk to health of foal and will influence options, determine whether mare or foal is priority Tips: - Follow mare around box during manipulation, but don't get caught in corner - A lip chain or twitch can give extra control - Only pull when the mare is pushing - When repelling foal, do not push when mare is pushing - Always cup hooves to prevent uterine damage

Answer 26

Offers perineal analgesia and reduces reflex straining, but no impact on abdominal efforts So tend not to do them

Answer 27

Standing Reduces abdominal pressure/straining and helps with correction

Answer 28

Moves tongue away from blocking epiglottis, so reduces thoracic pressure and therefore abdominal heaving

Answer 29

Might be useful by causing mild uterine relaxation Do not reduce abdominal contractions

Answer 30

Yes, very useful - domidine or xylazine +/- butorphanol But be aware will depress foal, particularly respiration

Answer 31

If want to stop abdominal straining

Answer 32

Allow complete umbilical

Answer 33

More often in a mare that foals standing up - often maiden or unsettled mares Rotate the foal whilst supporting the body Allow complete umbilical blood flow if possible

Answer 34

Umbilical blood flow often interrupted quickly and lead to bleeding from umbilicus and placenta more likely to be retained

Answer 35

= Premature placental separation Waters do not break Thick, red, velvety membrane at vulva Foal and placenta delivered together Foal can asphyxiate Major emergency! Instruct owners to act immediately - break membrane and pull foal out (sometimes will rupture on its own before cutting)

Answer 36

Different appearance Red bag - darker red, velvety Bladder retroflexion extremely uncommon

Answer 37

Can cause early rupture of umbilical cord Gets stuck at chest Rapid delivery essential: Oxygen for resuscitation Monitor foal for PAS Note - feel along cannon bones and if feel point of hock then know it's the back legs coming first

Answer 38

Reduce straining - drugs etc Ideally mare standing Pull head round, reaching for neck first, then jaw, then nose - Long arms are useful! - if no space to do this, repel foetus backwards Can be difficult, as neck is long

Answer 39

Generally will not come out like this, so need to reposition Reduce straining - keep mare standing, pull tongue out, sedate Repel foetus Correct flexion/ropes - If shoulder flexion, reach along to feel forearm and move into a carpal flexion by moving knee up to be alongside correct leg, then cup the foot and move to midline of the foal as more space there to flick it up into correct position (repel foetus more if need more space) If not managing to move a carpal flexion, may be because there is carpal contracture (congenital abnormality) - care as may not be possible to reposition and risk damaging mare, may require C section

Answer 40

If dystocia, easier to repel foetus and correct it before it has been jammed into the birth canal

Answer 41

Don't keep pulling and pulling Could be a 'dog sitter' - hind feet get stuck under the pelvis. Feel for hind hooves at or under pelvis. Can be very difficult and frustrating. Sometimes repelling the foal and letting the hind legs fall back into abdomen may resolve this, mare getting up and moving around may help. Poss try using embryotome repelling rod to push hind legs back at the level of the hocks, or GA. May need C section.

Answer 42

Increases the diameter from the dorsum to the ventrum, so vagina/rectal tears more likely and 3rd degree perineal laceration or recto-vaginal fistulas Repel foetus, place legs under head, deliver (owner can often do this easily) Worth correcting to reduce risk of damage to mare

Answer 43

Sort out legs/head and deliver one at a time

Answer 44

Breech presentation - posterior with hip flexion Reduce straining Attempt correction - repel, bring both hindlegs into pelvic canal into hock flexion, then correct the hock flexion into normal posterior presentation and deliver Difficult as hindlegs don't move independently and need a lot of space to move into correct position GA and/or C section often indicated (or foetotomy if foal dead)

Answer 45

Vaginal delivery under GA Can produce a live foal Need to elevate the hindlimbs Stops abdominal contractions and allows use of gravity to repel foal Short GA

Answer 46

Yes, but be aware risk to foal and not allowed to have person travel inside with them Consider intubating foal

Answer 47

Only if foal is dead Performed on standing mare Sedation/epidural Careful to avoid damaging cervix No GA, no surgical healing Needs specialist equipment and experience Aim for 'one cut'

Answer 48

GA of mare, cut foal out, then euthanise mare E.g. if mare has severe orthopaedic injury But must be prepared to resuscitate the foal No point getting foal out if haven't got the equipment needed for the foal afterwards

Answer 49

Failure of the foal to absorb sufficient immunoglobulins (antibodies) from colostrum Maternal causes: - Runs milk pre-foaling - Won't let foal nurse - Poor quality colostrum or low quantity colostrum (often maiden mare) Foal based cause: - Foal that can't nurse - Foal that can't stand due to weakness or flexural limb deformities - Foal with hypoxic ischaemic syndrome - Foal that ingests colostrum but inadequate absorption by GIT due to prematurity or sepsis

Answer 50

No - foals are born agammaglobinaemic at birth (no circulating antibodies in blood) Due to the type of placenta - foetal chorionic epithelium is separated from the maternal blood by 3 layers of tissue, which prohibits the transfer of macromolecules (including immunoglobulins) from dam to foetus

Answer 51

Absorption of IgG across the GI tract is maximal at birth until around 8 hours post foaling Rapidly declines after this, until closes at 24 hours

Answer 52

Sepsis and death in the foal's first month of life

Answer 53

Measure foal's serum IgG concentration within the first 18-24hrs of life - Radial immunodiffusion (RID) is gold standard - Serum electrophoresis second best - Immunocrit method recently described (see 2020 paper) - POC ELISAs and turbimetric immunoassays also available, Idexx foal IgG snap test is practical and user friendly although not quantitative (provides 3 categories of <400, 400-800 and >800, which is sufficient for most clinical purposes) - If no access to equipment but can do biochemistry, can use regression equation to estimate IgG: IgG = -241.4 x [albumin] + 462 x [globulin] + 222.8 x [TP] - 370.3 >800mg/dL = adequate passive transfer 400-800mg/dL = partial FPT <400mg/dL = complete FPT Cut offs supported by Liepman et al. 2015 (found <800 was proportionally related to mortality of hospitalised foals) Note - IgM and IgA also present in colostrum, but we routinely just measure IgG

Answer 54

Newborn foal that has not/will not consume adequate quality colostrum -> supplement with assured quality colostrum within the first 12-18 hours of life (as early as possible) -> monitor IgG levels Foals aged 18-24hrs + with complete FPT -> plasma transfusion Partial FPT - decision depends on multiple factors (e.g. infectious disease risk at small home yard vs studfarm vs hospital, finances, health status of foal, requirement for insurance)

Answer 55

200-300mg/dL May choose to give 1 bag, retest IgG and then give another bag if needed OR also reasonable to give 2L straight away to complete FPT if finances allow Tend to see a smaller increase in septic foals

Answer 56

Requires monitoring due to small risk of anaphylaxis Plasma should be slowly defrosted in lukewarm water (do not microwave or overheat) Sedation if required (depends on the assistance available) Aseptically place a short stay catheter Use a double filter giving set and begin on a slow drip rate (0.5ml/kg over 10-20 mins = 25ml for 50kg foal), whilst monitoring the foal for any signs of transfusion reaction (e.g. tachycardia, muscle fasciculations, respiratory distress, pyrexia, collapse) - stop if so Increase speed to 40ml/kg/hr if no adverse effects are observed If using for hypoproteinaemia/SIRS/sepsis etc, rather than FPT: CRI of 1-2ml/kg/hr as needed for colloid and albumin replacement

Answer 57

The second most common immunologic disorder of foals (after FPT) and the most common cause of icterus in newborn foals Increased risk to foals born to multiparous mares, or mares which have previously produced a NI foal Autoimmune disease The foal's red blood cells are destroyed by preformed maternal anti-red blood cell antibodies, which are ingested in the colostrum -> anaemia Severity varies from mild to life threatening, depending on severity of anaemia and subsequent hypoxia

Answer 58

1. Blood group incompatibility between mare and foal (foal must have inherited a RBC antigen from the sire that is not possessed by the mare) 2. Maternal sensitisation - the maternal antibodies are produced in response to exposure of the mare to 'foreign' RBC antigens e.g. if placental pathology leads to exposure to foaetal RBCs during pregnancy, prior exposure to foal RBCs during previous pregnancies or foalings, or prior incompatible blood transfusions to the mare 3. Absorption of antibodies in colostrum

Answer 59

Most blood group antigens are not strongly immunogenic Factors Aa and Qa are strongly immunogenic and have been implicated in the majority of historical cases of NI

Answer 60

Mules (= donkey sire and horse dam) 10% (thoroughbreds 1%) Mule foals possess a donkey specific RBC antigen ('donkey factor') that horses lack

Answer 61

Typically born clinically normal Develop signs within 2-5 days of birth, due to anaemia Progressive lethargy, weakness, tachypnoea, tachycardia Mm may be pale, progressing to icteric Pigmenturia (haemoglobinuria) may be present and reflects severe haemolysis (urine may be red) Severe disease -> dyspnoea and seizure like activity may occur (likely due to kernicterus due to severe hyperbilirubinaemia)

Answer 62

Anaemia - typically PCV of 10-20%, but may be as low as 5% Elevated blood lactate due to reduced perfusion from reduced oxygen carrying capacity of the blood Hyperbilirubinaemia (with greatest increase in the indirect component) due to mass destruction of RBCs Might see increased sorbitol dehydrogenase (liver enzymes) due to hepatocellular injury in severely affected foals either secondary to hypoxia or due to iron toxicity associated with bilirubin concentration Haemoglobinaemia and subsequent haemoglobinuria can be severe Pigment nephropathy can lead to AKI in severe cases

Answer 63

Sympathetic handling to minimise stress (restrict exercise) Muzzling and alternative nutrition if <24-36 hours old until gut closure to antibodies has occurred e.g. colostrum from another mare followed by milk feeds, usually via NG tube Judicious IVFT - supports tissue perfusion and cardiovascular fucntion and minimises nephrotoxic effects of haemoglobinuria, but be conservative with volumes to avoid further haemodilution in an already anaemic animal Check IgG status and plasma transfuse if necessary Signs of hypoxic shock e.g. persistent or progressive tachycardia and/or increased RR) -> transfuse washed RBCs from mare (easiest option) - Keep tranfusion volumes to a minimum (20ml/kg) - Transfusion volumes >4L associated with increased odds of hepatic failure - Use double filter giving set - Monitor for signs of transfusion reaction - Start slowly and then speed up after 10 mins Deferoxamine mesylate (desferal) - increases urinary excretion of iron and may reduce hepatic damage due to iron toxicity, 2010 study used 1g SC BID dose, not too costly (Intra-nasal oxygen insufflation? Minimally useful as oxygen saturation typically high but oxygen carrying capacity is limited)

Answer 64

Provisional diagnosis made based on signalment, history, clinical signs and biochemistry Definitive diagnosis: presence of antibodies in the mare's colostrum or serum are demonstrated to be directed against the foal's RBC antigens - Test of choice is the haemolytic crossmatch of mare serum with foal RBCs using exogenous complement - Agglutination tests are less reliable but more commonly used as they are readily performed and provide rapid results - The JFA test is performed using RBCs from the foal and colostrum from the mare, with agglutination as the endpoint. Lacks sensitivity and specificity, so more useful for prevention of NI rather than diagnosis of an affected foal.

Answer 65

Blood typing of mare prior to breeding - mares lacking factors Aa and/or Qa are at risk for becoming sensitised in the future - ideally these mares should be matched only to stallions that are also negative The JFA test can be performed after birth and before the foal is allowed to nurse In the absence of a JFA test, any foal born to a mare that has previously had a foal affected by NI should be considered 'at high risk' - foal should be muzzled at birth and not allowed to nurse for the first 24-48hrs (replace with colostrum from another mare)

Answer 66

Another autoimmune disease, much rarer than FPT or NI Affected foals ingest and absorb maternal alloantibodies directed against antigens on platelets or neutrophils Clinical signs: - NAIT: Petechial haemorrhages or prolonged bleeding from venipuncture sites, some may have crusting miliary/ulcerative dermatitis (esp. pectoral and groin region) - NAIN: Generally clinically normal but predisposed to secondary bacterial infections Incidence is difficult to determine as thrombocytopenia and nuetropenia are also common findings of septic foals May occur alongside NI +/- dermatitis, or alone

Answer 67

Persistent thrombocytopenia or neutropenia in the absence of an explanatory disease process, such as bacterial sepsis Checking PT and APTT aids in the differentiation of foals with NAIT from those with DIC secondary to sepsis - NAIT: PT and APTT are typically normal - DIC: PT and APTT are prolonged Bone marrow aspirates can be used to confirm adequate platelet production in NAIT (infrequently done in practice) Confirmation of the diagnosis is based on demonstration of antibodies bound to the patient's platelets or neutrophils (but generally work on clinical suspicion)

Answer 68

Supportive care: - Fluids and nutritional support - AM therapy where concurrent sepsis is suspected and foals with NAIN - Careful handling in NAIT foals (to avoid inappropriate bleeding) - Platelet rich plasma or whole blood transfusion (NAIT) - Corticosteroids - for both to inhibit destruction of neutrophils/platelets, but care taken as immune suppression in an immonologically naive animal not ideal, low dose for short duration of treatment - G-CSFs (NAIN) - may be considered if profound neutropenia Both conditions are ultimately self limiting because the maternal alloantibodies are consumed and eliminated from the circulation

Answer 69

Sepsis = life threatening organ dysfunction caused by a dysregulated host response to infection Septic shock = the need for the use of vasopressors to support blood pressure and lactate continuing to rise despite fluid therapy

Answer 70

Hyperactive pro-inflammatory response, rather than the usual controlled response which includes both pro- and anti-inflammatory mediators, together with immune, cardiovascular, haemostatic, endocrine and nervous systems -> multiorgan dysfunction, failure and death

Answer 71

Up to 1 week old (0-2d most common)

Answer 72

Blood glucose regulation - hypoglycaemia associated with positive blood culture, SIRS and sepsis Renal - AKI commonly seen with raised creatinine (but need to differentiate from the spurious high creatinine that can be seen in 1-2 day old foals thought due to placental dysfunction) Hepatic - might see elevated GGT and hyperbilirubinaemia (but no association found between the level of elevation of these and the severity and outcome of the disease process) Respiratory Cardiovascular Gastrointestinal Endocrine

Answer 73

Sepsis: creatinine won't quickly reduce and is often associated with fluid and electrolyte disturbances Spurious: temporarily elevated, should see a drop in creatinine by 50% after the first 24hrs post partum Spurious hypercreatinaemia can be seen in 1-2 day old foals, thought due to placental dysfunction

Answer 74

Foal: - Age (typically 0-2d, can be up to 7d, much less likely beyond this) - Abnormal adaptive behaviour (slow to suckle) - Failure of passive transfer immunity - Focal infection - High environmental challenge Mare: - Illness during pregnancy - Placentitis - Premature lactation - Short or prolonged gestation - Dystocia - Abnormal placenta/foetal fluids - Foaled unattended (period where unknown foal behaviour)

Answer 75

Reduced nursing Demeanour Behaviour - e.g. lying down more, less interacting with mare and people, just standing still lots Cold extremities Tachycardia Hypo or hyperthermia Increased CRT Icteric, dark red or injected mm Coronitis (inflammation around coronary band) Decreased urine production (difficult to assess in first 12 hrs as many normal foals won't have passed urine yet either) Signs of focal infection SIgns start off less specific and mild and progress as disease process continues

Answer 76

Early detection and diagnosis is vital Diagnosis based on clinical judgement in first instance: history, signalment and clinical signs POC clinical pathology Sepsis score Blood culture (positive confirms, but negative doesn't rule out as high rate of negatives in foals with high suspicion that do respond to AMs)

Answer 77

In people - one blood culture has 60% chance of finding microorganism Takes 4 cultures to get this to 97%

Answer 78

Don't delay starting AMs to take blood culture If already on AMs, take the blood sample for culture just before the next dose of AM Ideally take at first visit though if suspicious, so get results as quickly as possible (helpful if first AM doesn't work)

Answer 79

Some suggestion that bacterial load is higher in peripheral circulationgoat So consider taking from cephalic vein if possible Check the volume of blood needed for culture bottle (typically 10-20ml) If cost is an issue so can't do 2 cultures but want to increase chances of positive culture, could put 2 samples into same culture pot

Answer 80

Wong et al, 2018 ('evaluation of updated sepsis scoring systems and systemic inflammatory response syndrome criteria and their association with sepsis in equine neonates' - most up to date, modified and more practical version 12 or more correctly predicts sepsis 93% of the time 11 or less predicts non-sepsis correctly 88% of the time

Answer 81

Wong et al, 2018 Added the 2 yellow rows - no significant difference between the top 4 white columns alone, or if use yellow ones too If using all 6 columns, criteria to be SIRS is: - Must include at least 3 - Of those 3, must include abnormal temperature and either a leucocytosis or leucopenia

Answer 82

Moderate sensitivity and specificity Just gives an idea

Answer 83

Triage - stabilisation before anything else - Fluid rescuscitation - check blood glucose - Respiratory: intra-nasal oxygen (must be humidified if given for >1hr) - Reduce thermal losses (if hypothermia) - caution until resuscitated Then full thorough clinical exam Sample collection and clinical pathology - establish minimum database Early constitution of appropriate antibiotics Haemodynamic support Supportive care Other drugs

Answer 84

Blood glucose (POC useful) Lactate (POC useful) Haematology SAA IgG Fibrinogen Proteins Urea and creatinine USG and volume

Answer 85

The pathology is likely to have started in utero

Answer 86

48hrs (hopefully with blood culture results back)

Answer 87

Can't wait for blood culture results, need to start ASAP Infection may be polymicrobial Likely to have a compromised immune system - partial and complete FPT are a major risk for sepsis Poor perfusion is a common problem in neonates with sepsis Hepatic metabolic pathways may be less active over first 1-2 weeks after birth Renal function - efficient renal excretion, but function may be compromised by poor perfusion in a sick foal Plasma proteins may be low Consider the prevalence of local isolates and sensitivity patterns Must be: - Broad spectrum - Bacericidal - Usually go for: Penicillin or ampicillin depending on situation, with amikacin (or gentamicin but more nephrotoxic) - Ideally IV initially as smaller muscle mass and in some cases poor perfusion, so IM not ideal - Oral route rarely appropriate early in the course of the condition of sick neonates, maybe once foal starts to recover Protect 3rd and 4th generation cephalosporins whenever possible - justified to use if very worried about AKI and not wanting to use gentamicin or amikacin (e.g. ceftiofur alone instead), or if impractical to dose the foal appropriately for its age (can do ceftiofur BID and can move onto IM for owner to do) Read 2022 paper 'Systemic antimicrobial therapy in foals' by E.F.Floyd et al.

Answer 88

2019 paper looked at foals <30d old ('Initial antimicrobial treatment of foals with sepsis: do our choices make a difference?') Found 65% survival if all organisms sensitive to first choice antibiotics Reduced to 41% survival if one or more organism resistant to first choice AB 92% of isolates susceptible to amikacin and ampicillin 86% of isolates susceptible to ceftiofur, 90% if add amikacin (but note main reason to use ceftiofur is due to concern for kidneys so not appropriate to add amikacin)

Answer 89

Hydrophilic drugs (aminoglycosides) doses are higher in young foals with higher ECF Monitor weight of foal regularly and change doses as needed (if 50kg foal drops or gains 5kg = 10% of BW change)

Answer 90

Sepsis is likely to have resulted in damage to the endothelial glycocalyx (important for producing oncotic pressure and modulating transcapillary blood flow) Studies shown the retention of crystalloids vs synthetic colloids in the vasculature is very similar, so no justification for use of colloids Early fluid rescucitation: - 20ml/kg bolus over 20 mins - Check for response and repeat up to a maximum of 3 times in total Maintenance fluid therapy: - 3-4ml/kg/hr = 80-100ml/kg/day (if bolusing calculate 24hr volume and divide into dosing intervals) Plasma: - Likely needed - Quantity will depend on degree of FPT (1-2L for 50kg foal) - IgG levels can fall in these foals due to sepsis mediated breakdown of antibodies - May help restore the endothelial glycocalyx

Answer 91

Do no harm, consider evidence not acecdote Gastric ulcer prophylaxis - controversial as mechanism of pathology is different in foals and likely related to perfusion of gastric perfusion, ileus, hypoxia and changes in feeding. Case by case. Consider sucralfate (instead of omeprazole). Flunixin or other NSAIDs - care if renal function compromised. Consider meloxicam over flunixin. Polymixin B - some evidence to support its use, but nephrotoxic (6000u/kg IV infusion q8hrs wong et al 2013) Assess renal function before using any nephrotoxic drugs! Critical illness related corticosteroid deficiency (CIRCI): - Foals in septic shock that fail to respond to the normal critical care - Tapering dose over 3.5 days - Starting dose 1.3mg/kg/day of hydrocortisone divided into q4-6h intervals - Caution re potential nephrotoxicity Hart et al 2011

Answer 92

Good facilities - hygienic, able to control temperature (shut windows etc to remove draughts) Assistance available - experience level of owners, any foal sitters/students are nurses able to help Equipment and drugs needed Distance from practice - cost and ability for repeat visits

Answer 93

8L blood volume 4.8L plasma volume Very different proportion to adults

Answer 94

First 24hrs: 10-15% BW (5.5-8.25L for 55kg foal) First week: 20-28% BW (13-18L for 65kg foal) 4-6 weeks: 15-19% BW (16.5-21L for 110kg foal) Sick foal has lower energy requirement: 10% BW/day in mare's milk

Answer 95

Healthy: 150kcal/kg/day Sick: 50kcal/kg/day (uses less energy as often recumbent etc)

Answer 96

Approx 6ml/kg/hr = 7L for 50kg foal

Answer 97

Hyposthenuric <1.008

Answer 98

Poor pulse quality - feel peripheral pulses Cold extremities - good indicator, always feel distal limbs Obtunded Reduced urine output Prolonged CRT

Answer 99

Hartmann's (colloids not recommended in foals) Bolus 20ml/kg over 20-30 mins = 1L for 50kg foal Volume may need to be reduced if think unable to handle high volumes or if already any signs of tissue oedema Monitor response to each bolus, repeat twice more if needed If no response to 3 boluses likely to need blood pressure monitoring and CRI of inotropes and/or pressors -> really need referral to a hospital

Answer 100

1. Lack of appropriate resources - people, place, equipment/drugs, experience 2. Lack of response to fluid rescuscitation (no response to 3 x 20ml/kg IVFT boluses -> indicates needs blood pressure monitoring and CRI of inotropes and/or pressors) 3. Need for parenteral nutrition 4. Need for continued respiratory support (if needing O2 therapy for more than 1-2 hours) 5. Need for CRIs 6. Consider costs of managing in the field reaslistically

Answer 101

Aim to maintain both ECF and ICF Provision for abnormal ongoing losses e.g. diarrhoea (can lose considerable fluid and electrolytes) - foals are less able to concentrate urine

Answer 102

Foals have a reduced tolerance for Na+, so cannot cope with fluid overload in the same way as adults So, must monitor electrolyte levels and acid base - care to not cause sodium overload and hypernatraemia Readjust fluid rates as needed

Answer 103

Hyponatraemia is common Hypernatraemia: usually associated with fluid overload Hypokalaemia common in foals with diarrhoea

Answer 104

Acid base and electrolyte levels

Answer 105

Isotonic or hypotonic crystalloids Requirement for free water (especially if hypernatraemic foal) Avoid Na+ overload (in IV fluids and drugs e.g. ceftiofur) Hartmann's (131mmol/L Na) and/or 5% dextrose Plasma (135mmol/L Na) Calculate total daily Na intake and then make adjustments If concerned about hypernatraemia, tend to use 5% dextrose (unless problems with blood glucose regulation) In most cases of CRI, use 50:50 mix of Hartmann's and 5% dextrose Calculate all fluids for daily intake of fluid (incl IVFT, plasma, enteral/parenteral nutrition - don't overload)

Answer 106

3-4ml/kg/hr + excessive losses = 80-100ml/kg/day = 3.6 - 5L per day + excessive losses In certain circumstances when concerned about young, sick foal's ability to manage fluid balance e.g. if tissue oedema or oliguria/anuria, then 'dry maintenance' may be used (increasing evidence that excess fluid can be detrimental): Palmer 2002 Holliday Seager 'dry maintenance' calculation: - 1st 10kg BW: 100mg/kg - 10-20kg BW: 50ml/kg - 20kg+: 25ml/kg = just over 2L of fluid per day for 50kg foal - don't tend to use this much, especially if diarrhoea Vital to continually monitor the foal's response to fluids (clinical and lab), adjust rate as needed Include all fluid volumes for daily calculations (incl IVFT, plasma, enteral/parenteral nutrition) - don't overload If doing in field, often will bolus the maintenance fluids: - Calculate 24hr requirement and divide over 4 or 6 intervals (if only doing 4 visits, will have to give larger volume at a slower rate) - the smaller the intervals, the more physiologic

Answer 107

Compromised lung function is common in recumbent foals Positioning can have a significant effect on PaO2 in foals - chest wall is very compliant and lungs are stiff (reverse to adults) Aim to maintain sternal recumbency as prolonged lateral recumbency risks ventilation/perfusion mismatch and atelectasis - use pillows, wedges, hay bales, person sitting with them If has to be in lateral recumbency for any reason, must turn every 2hrs, ideally every 1hr over the first day or two Intranasal oxygen: - Intranasal catheter to level medial canthus (measure and marker with pen so know sitting in correct place when put in nose) - can then use syringe barrel and tape to nose (stitch to nostril if leaving in place and not there to monitor) - Flow rates 2-20L/min (depending on severity of resp compromise, start on 2L/min and increase quickly if needed, drop down as needed, avoid high rates for long periods) - Humidify with sterile water with long term insufflation (>1hr) to avoid negative effects on mucociliary escalator and respiratory defence mechanism (don't want to further compromise sick foal) - refer if need O2 for more than 1-2 hours so can properly monitor - Monitor PaO2 (aim for >80, run into trouble if dropping towards 60) or SaO2 (aim for >90) - SaO2 less useful but more practical If have hypercapnia due to hypoventilation (e.g. lower than expected RR): - Doxapram infusion - Caffeine

Answer 108

Compromised neonates have a poor ability to regulate temperature Resting metabolic rate increases at environmental temperatures <20C for pony foals and <10C for TB foals Normal range 37-39C

Answer 109

Start by reducing further thermal losses - raise off of the floor, not on duvet/vetbed, using rugs, avoid anything on limbs as poor perfusion so risk of dequibtous ulcers, shut doors and windows, avoid draughts with bales of shavings/straw Provide cardiovascular support and correct hypoglycaemia first

Answer 110

Can be any of the above! Often hypothermic when found in the morning septic

Answer 111

Don't overheat or over rug Get temperature of room down?

Answer 112

Blood glucose - True metrix air Blood lactate - Accutrend Plus

Answer 113

Make sheet to record everything at each check - monitor trends to see how responding to treatment Clinical exam Foal side tests - blood glucose, lactate, IgG Urine output and USG - have pot ready with person sitting with foal Nutrition Fluids ins and outs Lab tests - haematology, SAA, fibrinogen, renal enzymes, electrolytes

Answer 114

0.21MJ/kg/day maintenance (half of that of a healthy neonate as less movement, not growing whilst sick) Once start to stabilise, should start to gain weight Overfeeding human patients with sepsis can adversely affect outcome Thermoregulation - will need more energy if having to keep warm in cold environment

Answer 115

Advantages: - Physiological - Most balanced nutrition - Luminal source of nutrients for the enterocytes and help maintain integrity of mucosal barrier - Galacto-oligosaccarides in the milk will have positive immunomodulatory effects - Cheaper and easier to manage But need to assess and monitor GI function to ensure we don't cause problems e.g. ileus Assess with: - Regular abdominal auscultation - Checking for reflux (if <50ml ok to feed, 50-100ml halve feed amount, >100ml don’t feed) - Monitor faecal output - Abdominal circumference - put sharpie marker on foal where measuring so is consistent - US: monitor motility Enteral route not appropriate if ileus/lack of borborygmi, poor perfusion, reflux, hypothermia, colic or enterocolitis, abdominal distension - Then have to use IVFT and glucose for maximum of 24hrs or refer for parenteral nutrition

Answer 116

Consider parenteral nutrition if 10% enteral nutrition can’t be reached within 24hrs - but some human studies suggest early start of parenteral nutrition actually increases risk of mortality and infections Simplest option is IV dextrose supplementation e.g. if able to give some enteral nutrition, but need some more energy: - 4-8mg/kg/min (this is the same rate of glucose provision by the placenta) - 5% dextrose = 0.17kcal/ml ->5ml/kg/hr rate supplies 20kcal/kg/day - 50% dextrose = 1.7kcal/ml -> 1ml/kg/hr supplies 40kcal/kg/day - CRI optimal but some foals do tolerate glucose boluses Full parenteral nutrition = usually 50% dextrose, intralipid 10% and amino acids 15% - Aim for 50kcal/kg/day - Aims to supply glucose at 10g/kg/day, amino acids at 2g/kg/day and lipids at 1g/kg/day - E.g. 666ml (400kcal) bag Aminoven 15%, 1000ml (1700kcal) bag Glucose 50%, 500ml (500kcal) bag Intralipid 10% and 20ml Potassium chloride 15% = 2186ml, 2600kcal - Solution supplies 1.2kcal/ml - For 50kg foal target is 50kcal/kg/day =2000ml/day = 87ml/hr - Start at ¼ maximum calculated rate - Monitor closely - check glucose q4hrs - Minimum monitoring - glucose, triglycerides, electrolytes daily - Complications: hyperosmolarity, thrombophlebitis, hyperglycaemia, hypertriglyceridaemia

Answer 117

Atrophy of GIT Reduction in villi height Increased mucosal permeability - can lead to bacterial translocation (leaky gut syndrome) Decreased enzyme and hormone production

Answer 118

Ileus Necrotising enterocolitis Bacterial translocation

Answer 119

Providing tiny volumes of milk to foals that are not tolerating enteral nutrition well E.g. 25ml milk every 6-8 hours, or 20mg/kg/day glutamine solution (human glutamine powder) Provides some stimulus to reduce atrophy of GIT

Answer 120

Colic Severe enterocolitis Ileus/lack of borborygmi Poor perfusion Reflux Hypothermia Abdominal distension

Answer 121

Sepsis HIE/NMS (neonatal maladjustement synrome) IUGR/prematurity Those that need GI rest - colic, severe enterocolitis, ileus

Answer 122

If <12hrs: colostrum important, needs to be good quality as will be small volumes given After 12hrs, mare's milk is preferable - highly digestible, contains cytokines, lysosomes, growth factors, hormones (all support development of the foal's GIT) Failing that: - Commercial mare's milk replacer powder (based on cow's milk, less digestible, can feed at greater dilution rate than recommended by product so closer to dry matter content fed as mare's milk) - Or goat's milk (palatable, foal's do well, can be expensive for prolonged period time, similar protein to mare's milk, higher fat/calorie content) - Or skimmed cow's milk with added 20g dextrose/L (short term solution if middle of night with no replacement powder) Feed via bucket or bowl, not bottle (foals very prone to aspiration, don't have a good cough reflex) Or indwelling narrow bore feeding tube (suture to nostril) if any concerns about efficacy of suck reflex and pharyngeal function (can be compromised in foals with NMS - check before using bucket) - feed slowly by gravity flow q1-2hrs, kangaroo bag once significant volume Feed whilst standing or sitting

Answer 123

For foals with digestive problems 30-60mg/kg/day, divided into 4-6 doses Supports enterocyte function and digestive function

Answer 124

Aim for about 10% BW per day initially - introduce gradually Start at 5% BW (2ml/kg/hr) If this is well tolerated, gradually increase to 10% BW (4ml/kg/hr) Feed every hour for the first 2 days Then increase up to 8ml/kg every 2 hours for rest of the first week As the foal recovers and requirements rise as moving and gaining weight, gradually increase volumes to normal intake (approx 25% BW per day = 10-15ml/kg boluses every few hours) and return foal to nursing from mare as soon as clinical condition allows - introduce to mare gradually

Answer 125

Suitable environment and bedding - clean, dry (kennel liners useful if dribbling urine and bladder not catheterised) Catheter care - IV and urinary (maintain sterility) Umbilicus - frequent evaluation and care, 0.5% chlorhexidine, keep ventral abdomen clean and dry Eyes - risk of corneal ulcers, stain daily if recumbent Skin care - dry, clean, avoid pressure sores Physical therapy - stimulate and assist with standing and moving, stretch and flex limbs when recumbent, get standing and moving for short periods as soon as can even if need lots assistance, encourage interaction with the mare when possible even when down to maintain bond

Answer 126

Foals with either hypoglycaemia (<4.2mmol/L) or extreme hyperglycaemia (>10mmol/L) on admission are less likely to survive to discharge Both of the above were also associated with an increased risk of sepsis and positive blood culture

Answer 127

Glucose dysregulation: foals with either hypoglycaemia (<4.2mmol/L) or extreme hyperglycaemia (>10mmol/L) on admission are less likely to survive to discharge Lower repiratory tract disease Reduced PaO2 Increased lactate: for each 1mmol/L increase (above age normal) in admission increased the risk of non-survival Neutrophil-lymphocyte ratio: NLR <3.06 at admission associated with non survival Low neutrophil count: <6.24 associated with non survival Survival score: 96% se, 71% sp when using cut off of <4 days (avoids unnecessary euthanasia)

Answer 128

For each 1mmol/L increase (above age normal) in admission increased the risk of non-survival

Answer 129

Type A: due to decreased oxygen supply to the tissues, or increased oxygen demand Type B: impaired oxygen utilisation, or inability to remove lactate (can go up with inflammation and SIRS, or impaired renal/hepatic function) Foals increased lactate may be type A only or mix of both

Answer 130

Cold extremities Prematurity (<320 days) Number of sites of infection (>1) WBC (<4x10^3/L) IgG (<4g/L) Glucose (<80mg/dL = 4.4mmol/L) Survival score cut offs: 0: 3% 1: 8% 2: 18% 3: 38% 4: 62% 5: 82% 6: 92% 7: 97% Applicable to foals under 4do Can use app - 'FoalScore Ohio on iphone'

Answer 131

Consider euthanasia early on, rather than prolonged suffering and death

Answer 132

Works best in neonatal foal <24hrs old (can try up to 48-72hrs old but less reliable) Foals with mild signs of neonatal maladjustment syndrome (e.g. wandering, failing to interact with mare, unable to find udder and suckle after reasonable period of time, may have been fine for first 6 hrs but then seem to lose the connection and start sucking from walls/front legs etc but no other systemic signs of hypoxia) Can also be used for short period of restraint (10-20 mins) e.g. for exam, applying bandage, plasma transfusion (warn owner may still need sedation if not adequate)

Answer 133

Rib fractures - careful, thorough systematic palpation of thorax required (risk of serious secondary complications by causing damage to heart, lungs, coronary artery) Respiratory distress Foals requiring stabilisation (not appropriate for foals with severe signs, seizures etc, need stabilisation before considering this technique)

Answer 134

5-6m 16-20mm soft cotton rope that slides easily Clean towel to cover the upper eye (reduce stimulation) and protect the lower eye (avoid ulcers) Video on website 'Equine neonatal medicine madigan': https://www.equineneonatalmanual.com/foalsqueezing If using for restraint, let foal have feed from mare first Keep foal near mare, don't hold too tight whilst getting rope into place Put knot at withers at midline, with other two loops no more than 15cm between eachother Ensure symmetrical and pull from directly behind foal once ready Usually see typical breathing pattern of a foal when asleep - period of rapid breathing followed by a pause and slower breathing Keep down for 10-20 mins, or once starts to wriggle if for restraint Hopefully with MAL then go and suckle afterwards quite quickly Can repeat the next day if needed

Answer 135

3 months of age

Answer 136

70-80% of foals will have at least one episode of diarrhoea in their first 6 months of life

Answer 137

Small intestinal in origin (enteritis, not colitis)

Answer 138

Most commonly between 5-35do (but can be from 2do to 5mo)

Answer 139

Type A Type B been reported in foals in Kentucky (there are some UK labs able to test for B strain)

Answer 140

<10do C perfringens: most commonly type C (can be A) C dificile

Answer 141

Yes, can shed both, despite clinically normal Paper from Kentucky found similar Clostridial perfriengens and dificile toxin shedding between foals that did have diarrhoea and those that didn't Therefore, the significance of the finding isn't always known - careful to overinterpret, especially if clinical presentation doesn't fit with Clostridia May be something else going on

Answer 142

Has not been routinely looked for in UK so far Part of the normal flora in horses But recent paper found Enterococcus durans to be associated with diarrhoea in foals, compared to those without

Answer 143

Detailed clinical history - individual foal and farm, outbreak or single case?, FPT?, vaccination, worming on yard, movement of horses, biosecurity Detailed clinical exam - nature of diarrhoea (consistency, colour hemorrhagic, frequency), age, severity of disease, are SIRS/septicaemia present, concurrent problems? Clinical pathology - as a baseline always do: haematology, biochemistry including electrolytes, lactate, inflammatory markers and likely also BG (depending on foal age). In younger foals may also do: blood gas analysis, IgG, blood culture. Also faecal testing. Abdominal ultrasound Abdominal Radiography Sepsis score Intestinal lactose absorption tests if applicable Definitive aetiologic diagnosis can be challenging

Answer 144

Initially may only see colic or abdominal distension Depression Weakness Anorexia Salivation or bruxism Diarrhoea Hyperthermia May have evidence of SIRS (tachcardia, weak pulses, tachypnoea, congested mm, cold extremities) - can progress to coma and death

Answer 145

Remember coinfection possible! Use faecal sample or rectal swabs Commercially available and relevant tests: Salmonella PCR (3-5 consecutive daily samples) or culture Clostridial dificile/perfringens toxin ELISAs (+ toxin gene PCR) Cryptosporidium ELISA or PCR Rotavirus PCR (RVA and RVB) or ELISA Coronavirus PCR FWEC Lawsonia intracellularis PCR (folder older foals 4-7mo) (beware shedding is variable and intermittent, so can get false negatives, especially if antibiotics have already been initiated) Rhodococcus equi PCR (not always reliable and normal foals can also shed Rhodococcus) Other bacteria: aerobic and anaerobic culture

Answer 146

Perform in all neonatal foals with diarrhoea, most young foals and some older foals too Assess intestinal contents, wall thickness and amount of visceral distension Assess for pneumatosis intestinalis (gas within the intestinal wall associated with Clostridial disease) and other abnormalities e.g. intussusceptions Can also check for internal umbilical remnants and possible sites for abdominocentesis

Answer 147

Additional evaluation of GIT and assessment for sand

Answer 148

Largely supportive (similar to colitis in adults) Farm management vs referral (depends on age of foal, severity of disease, experience of personnel of these cases, vet availability) Nutrition Absorptive/adsorptive agents? Antimicrobials? Modification of the GI microbiota Anti-inflammatory and antiendotoxic therapeutics Other adjunctive therapies General hygiene and biosecurity Fluid therapy

Answer 149

Older foals (4wo+) are more resilient - larger body size with energy reserves - can cope with short periods of negative energy balance and so less intervention needed Monitor weight and BCS and intervene if nutrition inadequate

Answer 150

Inadequate nutrition may have a negative effect on immune response

Answer 151

Clinicians vary in approach - no real evidence for morbidity and mortality associated with different practices Generally don't restrict, unless signs that foal can't tolerate enteral feeding Older foals (4wo+) may continue to eat hay, even if nursing less (can be useful for maintaining energy provisions)

Answer 152

4 weeks old +

Answer 153

If longer standing diarrhoea Avoid glucose for fluid resuscitation For maintenance, can tolerate a low glucose concentration solution well (1.2% glucose solution) Or if managing on farm, can tolerate boluses of up to 2.5% glucose solution - helps with caloric provision and more practical than CRI

Answer 154

BioSponge: - 2,4,di-tri-octahedral (DTO) smectite - Neutralises and bind C dificile and C perfringens toxins in vitro (likely also in vivo and possible also other pathogens) - 3 tablespoons in 30ml water q6-12hrs for 50kg foal - very useful in foals, but monitor faecal consistency if start to firm up and become constipated - This is the author's go to out of them all Pepto-Bismol - Bismuth subsalicylate - May have local anti-inflammatory properties in GIT - 1ml/kg PO q4-6hrs Kaolin/pectin formulations: - Kaolin is a natural binding agent and helps firm up faeces - Pectin is gelatinous and we think coats and soothes GIT - 4-8ml/kg PO q12hrs Activated charcoal Pre/probiotics (e.g. Gut Bind) and electrolytes

Answer 155

More prone to bacterial translocation from gut leading to sepsis than adult horse, due to compromised mucosal barrier Yes to using them if: - Signs/suspicion of bacteraemia and sepsis (use ASAP!) - typically young foals - All young foals <4 weeks old as prophylaxis of bacteraemia - Leucopaenia/neutropenia in any aged foal

Answer 156

Broad spectrum Beta-lactam and aminoglycoside (ensure to monitor hydration and renal function) Or 3rd generation cephalosporin alone Review susceptibility patterns from hospital and farms if possible Add in metronidazole if Clostridial enteritis

Answer 157

Oral or IV <7do: 10mg/kg q12hrs 10-12do: 15mg/kg q12hrs >2wo: 15mg/kg q6hrs, or 20mg/kg q12hrs

Answer 158

No, they are born without intestinal bacteria Rapid colonisation and mature community by 6 weeks of life But microbiome continues to differ to adults until approx 9mo

Answer 159

Evidence base is conflicting and inconclusive Some documented adverse effects when used for very young, healthy foals Likely safe in older foals

Answer 160

Succesful for CDI and ulcerative colitis in humans Mare = suitable donor for foal?? Or pasture mates (must health screen) Must prep the recipient with acid suppression, before giving FMT Anecdotally useful in adult horses Potential use for foals

Answer 161

Live use Saccharomyces cerevisiae Only 2 products which provide this yeast according to current regulations Can improve diversity and stability of intestinal microbiome (but no evidence in foal specific microbiome yet)

Answer 162

Butorphanol - low doses very useful for young foals Hyoscine Lidocaine CRI for severe/pesristently painful cases (beneficial also for ileus) NSAIDs - judicious use (monitor hydration and renal function), meloxicam usually

Answer 163

Not often used in practice 2013 paper showed it can attenuate clincial and serum biochemical derangements that were present following experimentally induced endotoxaemia Potentially an option to use

Answer 164

Lactaid tablets 3000-6000 FCC U PO q6h When we suspect a lactase deficiency, or a lactose intolerance (primary or secondary)

Answer 165

Controversial Benefit of omeprazole acid suppression is unproven in foals and can be associated with development of diarrhoea in hospitalised foals So not mainstay therapy but case by case Sucralfate is an excellent alternative in foals with multiple positive benefits

Answer 166

Anti-diarrhoeal drug Works to increase intestinal segmentation rate and slow transit time For noninfectious causes only, as could enhance toxin absorption in foals with an infectious enteritis Not used commonly, but is an option

Answer 167

Keep on clean bedding Regularly clean the perineum and apply barrier cream to hind end to avoid scalding from diarrhoea

Answer 168

Clostridial spores are highly resistant to disinfection Need to use bleach

Answer 169

For biosecurity - avoid mixing foals of different ages Avoid hot spots developing on farm for infection

Answer 170

Greater total body water % and greater ECF % than adults Together with their increased metabolic demands for growth, this means they have a greater requirement for water intake

Answer 171

Fluids which contain small solutes - usually electrolytes, sometimes glucose

Answer 172

25% Similar osmolarity to ECF and plasma, so solutes rapidly cross semi-permeable membranes and fluid follows

Answer 173

Plasma and ISF are very similar (make up ECF) - high in Na+ and Cl-, low in K+ ICF - opposite way round, high in K+, low in Na+ and Cl-

Answer 174

Replacement (typically used for initial resuscitation): - High Na+ and Cl-, low in K+ - Therefore, good replacement of vascular and interstitial fluid and electrolytes - Hartmann's - (Saline) Maintenance: - For ongoing fluid provision - High K+, low Na+ and Cl- - Generally need to supplement the potassium supplementation, especially if not nursing - Half strength saline (0.45%) - can add KCl to change its osmolarity closer to plasma, or add 2.5% dextrose - 5% dextrose solution - if just want to give free water, has an osmolarity similar to plasma - Dextrose 4% in saline 0.18%

Answer 175

Saline is higher in Cl-, relative to normal plasma So can cause a metabolic acidosis Hartmann's is more alkalising, as contains lactate as a buffer Only really use saline for conditions when want no K+ (not present in saline, present in Hartmann's)

Answer 176

K+ is intracellular, so difficult to calculate the true deficit of a hypokalaemic foal Rate of K+ admin is important (do not exceed 0.5mmol/kg/hr) So for 50kg foal, this equates to no more than 25mEq/hr Do this by adding 20mEq of KCl per litre of fluids - unlikely to have a problem with this dose if run in too quickly as only 1L at a time Can increase to max 40mEq/L in some cases, but monitor rate closely If give too fast, will induce arrythmias and risk cardiac arrest and death

Answer 177

Na provision is often more than is required by foals Some critically ill neonates can be poor at regulating Na+ and may have a concurrent nephropathy - risk of Na overload in young foals and cause hypernatraemia BUT A diarrhoeic foal may be hyponatraemic (tailored fluid plan required, may be best to use replacement fluids for maintenance)

Answer 178

Foals tolerate replacement composition fluids (e.g. Hartmann's) for maintenance better than expected Kidney's are typically smarter than the brightest clinician! So, on yard will often just use Hartmann's But monitor electrolytes closely (at least daily, esp if diarrhoea)

Answer 179

20ml/kg rapid bolus (10-15 mins) Clinical reassessment of perfusion Repeat up to 3 more times if needed Aiming to rapidly restore effective circulating volume

Answer 180

Dehydration = loss of fluid from ICF and ISF Hypovolaemia = loss of fluid from vascular space

Answer 181

Need to look at the pump May need inotropes or pressors

Answer 182

Not necessarily Often the younger foals that are hypovolaemic and need rapid boluses

Answer 183

PCV Lactate Urine output/USG MM/CRT Daily weight if possible (Also monitor electrolytes daily)

Answer 184

Hyperlactaemia due to hypovolaemia and reduced perfusion to tissues But can also be due to electrolytes So important to measure both lactate and electrolytes

Answer 185

Lactate concentration should decrease But may be delayed if have tissue washout of lactate And some foals with SIRS/sepsis may still have high lactate even once volume is restored, due to other mechanisms

Answer 186

Hyponatreamia in up to 2/3 of foals with diarrhoea Hypokalaemia in 1/3 of foals with diarrhoea

Answer 187

Plasma [Na+] <120 mEq/L within hours can cause cerebral oedema <110-115mEq/L is associated with seizures - requires emergency treatment Chronic if hyponatraemia is present for >48hrs If hyponatraemia present for <24hrs: rapid correction is well tolerated If present for 3 days or more (esp if <120): rapid correction will result in cerebral oedema and osmotic demyelination

Answer 188

Correct plasma [Na+] by 4-6mEq/L in first 2hrs Humans: 3% hypertonic saline (0.8-1.8ml/kg bolus over 10-20 mins, repet 2-3x until reach desired [Na+]) In foals: use a low Na composition fluid (Hartmann's is appropriate for moderate hyponatraemia)

Answer 189

Use a low Na containing fluid (in humans, they use isotonic saline, in horses Hartmann's is appropriate for mild-moderate hyponatraemia), without exceeding correction limits Correction limits: - Not more than 10mEq/L in first 24hrs - Not more than 18mEq/L in first 48hrs - High risk - not more than 8mEq/L in ANY 24hr period - Do not increase the [Na+] by more than 0.5mEq/hr (aim for 0.25mEq/hr)

Answer 190

In acute cases where it has been present for <48hrs

Answer 191

Depression Restless Seizures if severe

Answer 192

Chronic hyponatraemia: brain adaptation changes occur to correct hypertonicity induced brain swelling, so now get a brain problem associated with too rapid correction of Na levels Acute hyponatraemia: a brain problem associated with low sodium

Answer 193

Provide fluid with a [Na+] 10-20mEq more than the foal's serum Na+ and monitor level q4-6hrs for the first 24hrs (and monitor urine output) This will often be Hartmann's (but beware of K+ also)

Answer 194

Desmopressin Causes water diuresis to further increase Na+

Answer 195

Not commonly used in foals May be used if persistent acidaemia due to hyponatraemia/relative hyperchloraemia, or loss of buffer It is a way to provide the foal with Na, whilst the chloride that would be given with other IV preparations Hyperlactaemia due to hypoperfusion must be corrected first (improve perfusion first) Bicarbonate deficit (mEq) = 0.5 x BW (kg) x Base deficit (mEq) Oral supplementation - 1g NaHCO3 = 12mEq of Na and 12mEq of bicarbonate - So if calculate deficit in mEq, divide by 12 to give grams Isotonic bicarb (1.3%) IV: - Commercially available solutions are all hypertonic, so need to make isotonic - Add 13g NaHCO3 to each 1L of sterile water - OR add 260ml of 5% bicarb solution - OR add 154ml of 8.4% of bicarb solution - Give first half as slow bolus, remainder over 6-12hrs - Do not combine with Ca+ containing solutions in giving sets (will cause precipitation) - Care in foals with respiratory disease (in case end up blowing off CO2) Monitor effect closely Account for a resolving disease process - may not need as much bicarb as the deficit suggests

Answer 196

Isotonic saline All other commercial fluids contain potassium

Answer 197

FPT Hypoproteinaemia SIRS or sepsis Coagulopathies

Answer 198

IV generally more practical in foals Small bore indwelling nasogastric tube great for intermittent milk feeding, but lots of possible complications if used for continuous oral fluids

Answer 199

More likely to be recumbent during colic and be dramatic compared to adult and doesn't mean it's severe More likely to be a medical colic, compared to an adult Can also be more subtle - reduced nursing, sham feeding, tail flagging

Answer 200

Meconium impaction - top of the list for 1-2do neonate, more common in colts due to narrower pelvic inlet Ruptured bladder Enterocolitis Dietary/lactose intolerance - e.g. been browsing mum's feed, lactose intolerance can be secondary to rotavirus infection Gastric/duodenum ulceration - generally foals that have undergone hospital treatment (so consider gastroprotectants pre-emptively for any hospitalised foal) SI/LI obstruction - displacements, volvulus, luminal material Congenital abnormalities (e.g. atresia ani/coli - can't produce faeces - progressively more uncomfortable and distended)

Answer 201

Thorough history - even more important than in adults e.g. has it passed faeces and urine yet, has it nursed well Observe behaviour before leaping into stable Full, thorough, clinical exam - check umbilicus, joints, any scrapes/wounds etc, eyes (ulcers common after colicing/recumbent) Digital exam - lubed gloved finger, if lots of meconium suggests impaction, check for atresia ani/coli - if any faeces in anal area Check for reflux - can develop substantial reflux (consider culturing reflux as lots reflux can be suspicious of enterocolitis) Take bloods Faecal testing if diarrhoea Stableside diagnostics - IgG (esp if <48hrs, low IgG is more likely to have meconium impaction - less colostrum = less laxative effect), USG (gives good idea of hydration - better than PCV, TP in foals, should be 1.000-1.006 - if concentrated suggests foal is getting dehydrated due to inadequate milk), glucose, lactate (gives idea of hypovolaemia/systemic state), SAA (less data in foals, useful for monitoring) Response to enema Also check the mare - if udder very full and leaking suggests foal not been nursing as well as owner might believe (may have been sham feeding) Don't do a belly tap (only if scanned and lots of free fluid, typically suggesting ruptured bladder) - can do more harm than good

Answer 202

Normal for it to be high, 2-4 (>5 concerning) Should start coming down after 24hrs

Answer 203

Fleet enema - human phosphate enema, insert and administer (only use 1 full fleet per 24hrs, as otherwise concern over phosphate toxicity) After fleet, move onto acetylcysteine retention enema: - Padding for foal to lie - hay bale, vetbed - Hindquarters raised up to get gravity to get fluid to go in and stay in - 8g acetylcysteine, 20g baking soda instilled and mixed in 200ml warm water - Sedate foal with midazolam (or a2 if needed) - Sometimes also buscopan to stop straining - 30Fr foley with 30ml balloon - lubrciate well and insert 2-5cm - Instill balloon - Attach syringe (without plunger) to act as funnel - Pour in and allow to flow by gravity - Then be patient, stay there for 30-40 mins, foal will start to wake up - Deflate balloon and gradually remove foley - If foal stays down longer then great - Breaking down waxy coating of meconium - Repeat up to q4hrs if needed but often don't need to Can also use soapy water enema - fiddly and less effective

Answer 204

Blood gas analysis Ultrasound Radiography

Answer 205

Metabolic acidosis most common Respiratory acidosis can occur Serum electrolyte derangements - helps rule in/out uroperitoneum (uroperitoneum classically high K+, Low Na+ and Cl-, enterocolitis with diarrhoea or reflux often low Na and Cl, as well as low K as taking less in from milk) Glucose and lactate usually included in blood gas, so don't need stableside tests

Answer 206

Get very fed up standing up, so generally get them in lateral with someone sat on them, then flip over and do other side Baby oil instead of spirit if possible - kinder to skin (clean off well if do use spirit) Linear probe (7.5-14MHz) or microconvex best for detailed view in foals (large curvilinear gives good depth but that is not needed in foals)

Answer 207

Abdominal effusion (anechoic fluid) Intestines floating in and out of picture If find large intact bladder can rule out If see effusion with collapsed bladder then highly suspicious of uroperitoneum

Answer 208

Distended viscera with mixture of gas and solid content (mixed echogenicity with gas), typically in caudal abdomen as comes through into SC and rectum, but can see it more cranial too, generally easy to see - lights up like a christmas tree

Answer 209

Distended loops SI filled with fluid, but good motility and mixing well - not sedimenting out like a strangulation May have thickened walls Look for gas in walls - pneumointestinalis suggests GI wall compromise, negative prognostic indicator, often gas in wall with Clostridia (fine to have gas in lumen, but not walls)

Answer 210

Target lesion - wall within a wall --> send to surgical facility quickly

Answer 211

May be violently colicy, and then transient colic Intussusception can move in and out

Answer 212

Lateral and dorsoventral views - can get full abdomen on one view Useful for obstructive disorders - meconium, atresia ani/coli Photo is meconium impaction - very gas distended with well defined gas opacity travelling backwards from rectum where meconium is impacted Congenital abnormalities - may see where there is gas distension in large colon, but does not continue into small colon, or can use contrast to show where does not communicate

Answer 213

Haematogenous spread - follows systemic disease in the face of impaired defences Primary infection elsewhere (usually umbilicus, respiratory or GI) + impaired immune system (especially if FPT) --> bacteraemia or septicaemia --> localisation into synovial membrane and cartilage (slow moving and rich blood flow to the end of long bones and synovium)

Answer 214

S-type = synovial type (infectious synovitis) E-type = epiphyseal type (infectious arthritis involving joint and adjacent epiphysis) P-type = physeal type (infection involving metaphyseal side of physis) T-type = tarsal or carpal bone type (infectious arthritis results in collapse of associated small carpal/tarsal bones I-type = periarticular soft tissue abscesses Should be a C to finish the acronym!

Answer 215

Closes at 7-10 days old Prior to this, S (synovitis) and E (joint and epiphyseal) types of septic arhtritis are more common (due to haematogenous spread to the synovium and epiphysis) After this, S and E still a common cause, but start to see increase in P type cause (metaphyseal side of physis)

Answer 216

Size of inoculum Host defence - FPT biggest risk factor Organism virulence - attachment factors, ability to resist phagocytosis, or resistance to cell killing Local joint factors - low blood supply and poor blood supply

Answer 217

History - Signalment (typically <4mo, but can be any age)? Normal pregnancy? Normal foaling? Normal progress of foal when born? Normal care? Increased recumbency? Progressive lameness? Did they dip umbilicus? Was IgG checked at 12-24hrs? Any diarrhoea? Full clinical exam, incl umbilicus assessment (pain, heat, discharge) - Static orthopaedic exam: palpate all joints (compare to contalateral limb, may be biltareal disease), check for any periarticular oedema and heat (can occur at the time of inoculation and prior to joint effusion) - Dynamic orthopaedic exam: lameness is often progressive (may just be reluctant to stand or increased recumbency to start with without lameness), gait may not be consistent, may skip from walk to canter making it hard to assess, also difficult if multiple limbs are lame Check mare - full udder suggests foal is nursing less Bloods - a normal haemogram doesn't rule out septic arthritis as infection can be very localised, but if neutrophilia or inc SAA/fibrinogen then supports infectious cause of lameness, biochem can help with maturity of foal and to check use of nephrotoxic drugs, IgG if <1mo, blood culture if suspect systemic septicaemia Radiography: -S-type (synovial) - minimal changes, might have soft tissue swelling only -E-type (joint and epiphysis) = lesions within epiphysis (radiolucencies) - if see this, monitor with repeat radiographs q3-5d - Check or concurrent fracture or osteomyelitis - May be minimal changes, especially initially (radiographical changes lags behind bone pathology) Ultrasound (for inciting cause e.g. chest, umbilicus, and the joint of suspicion) - anechoic effusion of joint, might be mixed echogenic flecks if fibrin tags, idnetify if any periarticular abscessation CT - costly, but can show osteomyelitis changes before radiography, particularly useful for axial skeleton and proximal limb which can otherwise be difficult to image, and for subtle lesions, can also assess chest (foalogram) (MRI, gamma) Synoviocentesis - key for diagnosis, degree/type of restraint dependent on age of foal (need as still as possible), stay away from wound if there is one (usually easy as effused), collect in EDTA for cytology and plain for culture, distend joint if wound to confirm communication, amikacin if any concerns about appearance of fluid, manual cytological smear if cell count doesn't correlate with suspicion (intracellular bacteria is gold standard finding), septic fluid is turbid, serosanguinous to purulent, reduced viscosity, >20x10^9/L, >80-90% neutrophils, TP>30g/L, can have grey area values if sympathetic inflammation due to infection in adjacent structure, culture (only positive in 40% cases, guides AB therapy if do get a result) - blood culture bottle increases chancem or centrifuging a small pellet of material

Answer 218

Might have been stood on, but ALWAYS consider septic arthritis (especially if owner didn't see mare stand on foal)

Answer 219

Stifle, hock and fetlock

Answer 220

Can appear irregular, which is normal - check contralateral limb if not sure

Answer 221

Any probe incl rectal and linear probes Omphalophlebitis is characterised by an increase in the size of the vein, measured in locations A, B and C (between umbilicus and liver) and an average taken, with thickening of the wall and the lumen is normally distended with hypoechoic material and sometimes hyperechoic gas (blood clots are normal - appear as homogenous hypoechoic structure within lumen) Omphaloarteritis - measured individually at E or as the combined unit at D

Answer 222

Treat underlying cause (ABs, hyperimmune plasma if needed, umbilical resection etc) Synovial lavage - needle through and through (GA or heavy sedation, asepsis and draping, 14G needles placed on opposite or on all 4 sides of joint if tarsus, alternate direction of the pressure by blocking ports and using different portals to maximise lavage, aim for >2L but a paper has shown anything >1L in tarsocrural joint made no further reduction in bacteria), or arthroscopic (preferred if chronic cases, or if suspicious if large pieces fibrin on US, allows targeted removal of fibrin and evaluation and debridement of articular cartilage if needed) Antibiotics - systemic (broad spectrum, bactericidal, guided by culture once get results, ampicillin and amikacin, or pen and gent, cephalosporins not first line anymore, note oxytet has good bone penetration so often used for E type but it is bacteriostatic so may not be ideal in young foals) and local (intra-articular, IVRP if periarticular abscessation, impregnated materials if associated wound, catheters if chronic and not responding to routine treatment - adjust doses to avoid systemic toxicity as small amounts can add up in small foal), duration of ABs depends on case but generally 1 week for S (synovial) type, may need more prolonged for E type (joint and epiphysis) NSAIDs - limited and judicious use (excessive use can affect kidneys, consider gastroprotectants Careful bandaging - excessive immobilisation/compression can cause rubs and contracture or laxity, so often just a covering bandage is adequate Sequential monitoring - lameness, pyrexia, repeat taps (aim for 2 improving taps 48hrs apart with latter being normal), repeat radiography if required Exercise restriction for 2-4 weeks even if immediately doing very well - likely underlying articular damage and want to limit that

Answer 223

Fair to good if: - Rapid treatment - Single joint - No bone involvement - Systemically well Guarded to grave: - Long time between dx and tx - >1 joint involved - Bone involvement (epiphyseal or physeal - E or P type infection) - Concurrent systemic illness (FPT, neonatal hypoxia, immune deficiency) Survival to discharge 90% for adults, 78% in foals (more systemic illness in foals) Return to athletic function 65% in adults, 67% of foals started >1 race with no difference in outcome to maternal siblings

Answer 224

Clinical exam - Similar symptoms to septic arthritis, but specifically oedema over growth plate and pain on focal pressure - usually quite painful response to this, whilst might not respond to flexion or other palpation Radiography - irregular/widened physis, focal radiolucency, soft tissue swelling Culture - blood culture or direct US guided aspiration from physis, or aspiration from joint if connects Treatment - antibiotics, incl local (injected directly into physis) and debridement (care as can damage physis by doing this) Prognosis guarded - risk of ALD if there is assymetric damage to physis, 50% will return to soundness

Answer 225

Painful, often skin changes - becomes very thin and hairless overlying abscess, often sloughs Ultrasound - might see some sympathetic effusion of joint, but majority of anechoic fluid +/- hyperchoic gas is adjacent to the joint and tracking along fascial planes +/- thick abscess lining Establish drainage, lavage, antibiotics, manage skin sloughing with longterm bandaging Prognosis depends on extent of lesion and how long need bandaging for afterwards

Answer 226

From increased recumbency --> thickened/leather like skin over boney prominences (epecially olecranon, point of hock, lateral malleolus, hip, styloid processes) Prevent with adequate bedding and analgesia so less time recumbent Treat with careful wound care

Answer 227

SEPTIC ARTHRITIS

Answer 228

Not common Usually due to trauma e.g. stepped on, or overzealous assistance during parturition - bone is weaker than the tendons etc in neonates, so will fracture before soft tissue injury

Answer 229

Type II = through physis and extending above through metaphysis Second most common = type I = simple fracture straight across physis The lower the number of classification, the better prognosis generally

Answer 230

Lameness Crepitus and instability (Wound) - impacts prognosis

Answer 231

Aim is to prevent further bone and soft tissue damage May need bandage cast and splint, or cast Don't bandage or splint proximal limb fractures - pendulum effect and can displace the fracture further Start antibiotics Generally travel in a separate partition to mare in box to referral hospital Open reduction and internal fixation often best - smaller size and weight is advantage for the implants available, healing time reduced compared to adults, but more technically challenging due to small and softer bone and involvement of physis Sometimes external coaptation suitable Some PTS

Answer 232

Infection and/or instability -> poor healing Limb deformities secondary to reduced weight bearing of fractured limb, or excessive weight bear of contralateral limb or damage to the growth plate during fracture or fracture repair

Answer 233

Characteristic swelling of the dorsolateral carpus,with swelling both proximal and distal to retinaculum Characteristic gait - flick the limb forwards, with knuckling Differ to flexural limb deformity as can be manipulated into full extension Ultrasound: - Often see anechoic sheath effusion - Hypoechoic to anechoic heterogenous echogenicity of fibre pattern - Loss of fibre pattern - Increase in adjacent cross sectional area - Often undulating appearance of adjacent tissue Conservative treatment: - Box rest - often this is all that is needed - Immoblisation - may be needed - Extensor supplementation with toe extension and bike tyres to mimic extensor function (if foal is walking on the dorsal aspect of fetlock)

Answer 234

Occasionally happens due to assistance during dystocia Inability to rise, dropped tarsus, often swelling over caudal thigh (often a haematoma, but can develop into an abscess), flexion of hock without flexion of stifle US: Rupture of muscle in supracondylar region, loss of architechture, may see avulsion fragment, may have haematoma/abscess Treatment: Exercise restriction and limb stabilisation Good prognosis with return to athletic function (82% returned to starting a race if have no complications)

Answer 235

Dropped elbow, inability to extend carpus Uncommon in foals - possible secondary to trauma Treat with splinting of carpus to allow extension for few weeks

Answer 236

Often conservative Limited exercise May use bandaging/splinting Corrective hoof trimming and glue on shoes to provide extension in the direction of intended movement - if have varus (i.e. medial deviation) then put on a lateral extension Limit nutrition Surgery sometimes needed - growth acceleration or retardation Prognosis good with early treatment if involves physis or epiphysis, fair-poor if diaphyseal, if crushed cuboidal bones or if severe angulation

Answer 237

Can manipulate joint back into a straight line if laxity Will improve with time and controlled exercise

Answer 238

Premature foals High risk of crushing injury to cuboidal bones and subsequent ALD Radiography - bones appear smaller and more rounded or not apaprent at all (grade 1 least ossified, grade 4 most ossified), always take LM view of tarsus as dorsal incomplete ossification can occur and may not be apparent on DP view Treatment - casts and rests, try to keep recumbent until ossification occurs Prognosis - grades 1-3 less likely to race, often other complications of prematurity/dysmaturity

Answer 239

Rare inherited condition (recessive gene), uni or bilateral and varied severity (intermittent luxation which readily reduces, to persistent luxation which cannot be reduced) More likely in foals with hypoplasia of lateral trochlear ridge of femur More common in mini breeds Unable to extend stifle so adopt characteristic crouched position Often diagnosed clinically, but radiography will confirm - but trochlear ridges on laterals may not be mineralised and may not be seen on skyline patella view, so US may be more useful Treatment - surgery or PTS Prognosis guarded

Answer 240

Deformity on saggital plane e.g. carpal/tarsal contracture - can't force joint into correct position Can contribute to dystocia - if severe may not be able to be delivered, or if it is often can't stand - poor prognosis and PTS likely Conservative - e.g. toe extensions, physiotherapy with controlled exercise, splints, analgesia Oxytetracycline? Used historically, poss inappropriate use of ABs, also nephrotoxic. Botox possible future use - soon to be published Surgery - tenotomy or check ligament desmotomy Also hyperextension - laxity of flexor tendons, walk with low pastern or walking on palmar/plantar aspect of pastern, correct with controlled exercise to strengthen musculotendinous unit (corrects in 1-2 wks for mild-moderate cases), occasionally need palmar or plantar extensions to elevate the foot, may need light bandage to protect the limb (as light as possible to avoid rubs, casts make worse)

Answer 241

Sepsis - lungs a common target Transitional circulation - prone to fliflopping between foetal and mature circulation Naive immune system Highly compliant chest wall - more difficult to maintain a functional residual capacity, which makes more prone to lung collapse and atelectasis Prone to atelectasis Intra and extra pulmonary shunting

Answer 242

Some foals will be in obvious respiratory distress, but others will have almost no signs, especially to start with Very easy to underestimate respiratory disease from a clinical exam in foals - may need ultrasound Cyanosis only seen with severe respiratory disease in foals

Answer 243

Keep in sternal recumbency - lateral recumbency leads to atelectasis (top lung is ventilated with air but bottom lung compressed and can't expand, blood flow sinks to the bottom lung leading to marked ventilation/perfusion mismatch) Sternal decreases the ventilation/perfusion mismatch Even in a normal foal, PaO2 can be 15mmHg lower when in lateral recumbency (will be even bigger difference in compromised foal) Use V pad, or hay/straw bales or person sitting with foal keeping propped up

Answer 244

First option is intranasal oxygen insufflation 2-15L/min - use the minimum possible flow rate to achieve desired effect on measured PaO2 (overoxygenating can cause problems e.g. damage to respiratory endothelium) Helps with mismatching, improves tissue oxygenation, decreases work/energy required to maintain same PaO2 Oxygen should be humidified (use oxygen bubbler) - otherwise can cause marked rhinitis and irritation Use nasal cannula - measure from nostril to medial canthus of the eye (important to measure carefully as if cannula goes too far into pharynx can lead to oesophageal insufflation, if not far enough into pharynx and just in one nasal meati then will massively reduce effect) Attach to foal's nostil with lollipop stick taped to cannula and around nose (some people suture in place - but be aware may have to replace twice a day due to plugs of nasal secretion), connect to oxygen tubing to cylinder

Answer 245

Maximising cardiac output is important to deliver oxygen to tissues and also to provide pulmonary perfusion

Answer 246

Caffeine 10mg/kg loading, then 2.5mg/kg PO SID (e.g. human Pro Plus tablets) Doxapram CRI 0.02-0.05mg/kg/min

Answer 247

Breaks up airway secretions - useful for things like bacterial pneumonia where there is lots of mucus etc Saline Salbutamol Acetylcysteine - if meconium aspiration, or lots of mucus (helps break it down) Antimicrobials? Not really responsible use, not ideal to nebulise into environment, probably better ways to give

Answer 248

Lots of evidence in humans to suggest preferable than mechanical ventilation (MV) where possible, especially neonates (longterm respiratory problems associated with preterm human babies with MV e.g. bronchopulmonary dysplasia) Other problems with MV - nosocomial infection, barotrauma, specialist facilities

Answer 249

Continuous positive airway pressure (CPAP): - Always providing some positive airway pressure, which keeps airway open and mantains functional residual capacity (FRC - foals struggle to maintain this due to compliant chest wall) - Nasal CPAP widely used in human NICUs - Increase pharyngeal cross sectional area - Enhance diaphragmatic activity - Improve pulmonary compliance - End result is decreasing airway resistance and work of breathing, and better V/Q matching - Couple of reports of good effect in foals - Can use cheap bed side machines adapted from treatment of sleep apnoea in humans - modified by adding anaesthesia mask suited to foals with holes drilled into it to allow the escape of gas, study used it set at 10cm water and 5L/min oxygen - Rossdales have tried this but found it difficult to get enough CO2 elimination Nasal high flow oxygen therapy (HOT) - Advantages over CPAP - easier to use and doesn't require a tight seal (actually important with HOT to not have a tight seal), very technically easy to use - Relies on supplying a very high flow rate of warmed, humidified oxygen - 40-60L/minute - Essential it is warmed and humidified otherwise would be uncomfortable and irritating to nasal mucosa - Works by generation of distending airway pressure, washout of nasopharyngeal dead space and reduction of work of breathing - Rossdales use Airvo 2 machine, made by Fisher and Paykel - technical note published in EVJ explaining how to use ('Nasal high flow oxygen therapy in hospitalised neonatal foals' - Emily Floyd et al) - Next level of respiratory support after standard nasal insufflation - useful for clinics which can't offer mechanical ventilation if no ventilator etc Some foals this will still not be enough - some need mechanical ventilation

Answer 250

Advantages: - Allows manipulation of pulmonary gas exchange - Treat hypoventilation - Improve V/Q mismatching - Open alveoli and reduce shunting - Maintain functional residual capacity (FRC) - Reduce work of breathing and respiratory fatigue

Answer 251

Acute respiratory failure Pulmonary hypertension Severe central respiratory failure (especially if haven't responded to chemical stimulants) Weakness - if not enough strength of lung wall to maintain adequate ventilation Prematurity Neuromuscular disorders

Answer 252

Arterial blood gas Pulse oximetry

Answer 253

Technically easy in foals Median artery in forearm: - Can use LA to desensitise skin, or EMLA cream if time - Feel the muscles of the forearm - artery runs just in front of these - Place 2 fingers either side of artery and can feel pulse running down - Use syringe or special arterial blood gas syringe which fills by capillary flow - Insert needle perpendindicular to skin, just through skin into artery and should fill quite easily - This artery is the easiest place to collect from as proximal so easier to palpate if foal with poor perfusion) Metatarsal artery - On distolateral hindlimb - Anatomically easier to identify, but can be more difficult to palpate if poor perfusion

Answer 254

pH: 7.35-7.45 PaO2: 65-85 (hypoxaemia if <60) PaCO2: 38-48 (hypercapnia if >60) Bicarbonate: 22-28 Remember aiming for PaO2 at least above 60 and PaCO2 below 60 Don't over do it - don't want PaO2 going above 100, ideally 80-90 if ventilating

Answer 255

Less invasive than collecting arterial blood But can be difficult to keep sensors on, unless foal is very floppy and recumbent Place on tongue or ear if not too darkly pigmented Study found it usually overestimated oxygen saturation, so should use a cutoff of 92%

Answer 256

Capnography and ECG (trace not useful whilst giving chest compressions, have to stop to check rhythm) (Pulse oximetry is pointless and BP not that useful either) Also blood glucose, blood gases and body temperature

Answer 257

Likely cardiac ischaemia, haemodynamic instability Possible brain injury SIRS not uncommon

Answer 258

Invasive = endotracheal intubation Non invasive = breathing support e.g. with facemask, providing positive pressure

Answer 259

Normal V/Q = 1 Low V/Q (reduced ventilation, with good blood supply) = Shunt perfusion = wasted perfusion e.g. airway obstruction, pneumonia, atelectasis, positioning High V/Q (good ventilation, with poor blood supply) = Dead space ventilation = wasted ventilation e.g. pulmonary embolism, cardiogenic shock, positioning

Answer 260

No - can have hyperoxia associated cytotoxic damage, pulmonary oedema, reactive oxygen species production