12. Question listed under Other

Question 1

Causes of microcytic hypochromic anaemia

Macrocytic

Nornoctyic

Answer 1

The patient illustrated has an microcytic hypochromic anaemia. Causes include
iron deficiency
and thalasaemia.

A macrocytic anaemia may be caused by
folate deficiency,
B12 deficiency and
alcoholism,

normocytic normochromic anaemia may be caused by acute blood loss,
haemolytic anaemia,
chronic disorders and
leucoerythroblastic anaemias.

Question 2

CPR
what is the sequence

how long can stop compression

tracheal admin drugs?

chest compressions while defib charging/

Answer 2

During cardiopulmonary resuscitation it is recommended giving 30 chest compressions at the rate of 100-120/minute and to a depth of 5-6 cm before giving two ventilations.

Chest compressions should not be interrupted for more than 10 seconds and should not be interrupted when an endotracheal tube is in place.

Chest compressions are now continued while a defibrillator is charged - this will minimise the pre-shock pause.

Tracheal administration of drugs is no longer recommended.

Question 3

Diamorhpine elixir

seadation?
admin

cocaine effects?

side effect

dependence?

Im dose via PO

Answer 3

Diamorphine elixir is used for analgesia in terminal care patients.

The sedation that occurs in the first few days typically wears off, leaving the patient alert. It is very lipid soluble and can be adminstered via mucous membranes (intranasally or buccally)

Cocaine is a topical local anaesthetic agent which does not enhance the analgesic effect of diamorphine but gives the patient unwanted hallucinations.

Constipation is a common side effect of opioids and an aperient should always be added to the treatment regime.

Addiction or drug dependence is not usually a problem in terminal care. Tolerance is a slow process results from liver enzyme induction.

An intramuscular dose of diamorphine is three times more effective than the same oral dose.

Question 4

PReop assesment given suggestion of anaphkaxis

Answer 4

As part of a preoperative assessment process, a thorough review a patients case notes and any previous anaesthetic records is mandatory.
Explanation
The patient gives a past history that suggests that she may have had an anaphylactic reaction during a previous anaesthetic. Her past notes would have to be reviewed to establish what course of events took place and if any investigations were performed. If the patient had been appropriately managed and investigated then a possible cause of her anaphylactic reaction would be known and a suitable anaesthetic management plan formulated. If not, then the patient should be referred to an allergy specialist for skin testing for the agents used at the time of her emergency appendicectomy.

Without further investigation it would be unsafe to proceed. It would be difficult to proceed with this laparoscopic surgery under regional anaesthesia.

Question 5

White coat in an otherwise healthy patient

Answer 5

In conjunction with British Hypertension Society, the AAGBI has published guidelines for the measurement of adult blood pressure and management of hypertension before elective surgery.

The key objective is to ensure that patients that are admitted for elective surgery are known to have a systolic blood pressure below 160 mmHg and diastolic blood pressures below 100 mmHg. The onus is on the primary health care teams to ensure that, if possible, evidence to the pre-assessment clinic staff or on admission, that this is the case.

A secondary objective is to avoid cancellation on the day of surgery because of spurious (“white coat”) hypertension. There are also guidelines on how to accurately measure blood pressure.

The primary recommendation is that patients who present to pre-operative assessment clinics without documented evidence of primary care blood pressures should proceed to elective surgery provided the clinic blood pressures are below 180 mmHg systolic and 110 mmHg diastolic.

This is the case in the clinical vignette and is supported by the fact that there does not appear to be obvious end-organ damage. There is no indication for further investigation for secondary causes of hypertension or an echocardiogram at this point. The patient will not require further review and treatment at this point.

In the interim, it would be prudent to write to the patient’s GP and encourage serial blood pressure measurements in the primary health care/community setting.

Question 6

Cricoid cartilage

is it the narrowest part of an adult airway

what about peads

whats the sellick manouevure

What pressure is recomended for crioid pressure

Answer 6

In adults the narrowest part of the airway is at the vocal cords, and in children it is at the level of the cricoid cartilage. The upper border of the cricoid cartilage is attached to the thyroid cartilage (not hyoid bone) and the lower border is attached to the first tracheal ring.

The application of cricoid pressure to control regurgitation (or reduce the risk of aspiration) of gastric contents during the induction of anaesthesia, was described by Sellick in 1961.There have been reports of pulmonary aspiration despite what was thought to be effective cricoid pressure. One possible reason is that the oesophagus is not exactly posterior to the cricoid and the manoeuvre might not necessarily in produce midline esophageal compression.

Based on studies of cricoid force to prevent material from reaching the pharynx, 40 N (10 N = 1.0 kg) was recommended.

Question 7

What helps relieve px oes spasm w/ tumour

What inhibit ostelcastic bone resportion and help rx bone px

What helps ibs px

what helsp CNS tumour px

what help bladder spasm

Answer 7

Nifedipine helps relieve painful oesophageal spasm and tenesmus associated with gastrointestinal tumours and could be used to relieve his odynophagia.

Clodronate inhibits osteoclastic bone resorption and is used to treat malignant bone pain and the associated hypercalcaemia.

Pinaverium is used to reduce the pain duration associated with irritable bowel syndrome (IBS).

Corticosteroids are used to treat pain from central nervous system tumours and painful bladder spasm may be relieved by oxybutynin.

Question 8

PALS algorithim

Answer 8

Paediatric life support is different to adult life support; the primary cause for deterioration is hypoxia.

Current advanced paediatric life support (APLS) guidelines stipulate that after checking for danger, a gentle stimulus should be applied (such as holding the head and shaking the arm) and asking the child “Are you alright?”. This is often remembered as Safety, Stimulate, Shout. These actions should precede any airway assessment.

Although five rescue breaths are included in the algorithm, these are performed after the airway assessment.

Asking parents to leave is not suggested unless they are obstructing the resuscitation. A dedicated member of the team should be with them at all times to explain what is happening and answer any questions.

CPR should not be commenced before appropriately assessing the child and delivering rescue breaths.

Question 9

DAS algorithim

Answer 9

Always call for help early. This patient is at risk of gastro-oesophageal reflux, the reason a rapid sequence induction has been opted for in the first place. The patient is not pregnant and the urgency of surgery is not immediate.

The plan A is to perform a rapid sequence induction under optimal conditions and successfully secure the airway with a tracheal tube.

Whilst no more that three attempts with direct laryngoscope (+ 1 attempt with videolaryngoscope) should be made to intubate the trachea the fact that the suxamethonium is wearing off should be borne in mind. One step is to ensure adequate neuromuscular blockade at this stage, this might include the administration of a non-depolarising relaxant if oxygenation can be maintained by bag-mask ventilation. As the surgery is not immediate there should be a low threshold to abandon attempts at intubation and resort to plan B.

An alternative strategy can then be planned.

The most important initial plan of action is to announce a “failed intubation” as this will stop you from persisting to intubate and alert your assistant that plan A has failed. Maintaining oxygenation and anaesthesia is also important prior to instituting plan B.

Do not give another dose of suxamethonium. Insert a supraglottic airway if there is failure of oxygenation and inability to maintain adequate ventilation

Plan D follows the declaration of a CICO

Question 10

Sacral hiatus
borders sup and lat

what level does cord term in kids

what level does the cauda term

What level does Dura extend to

what are complications
are they common

Answer 10

Failure of fusion of the laminae of the fifth sacral segment results in the formation of the sacral hiatus.

The sacral cornua form the lateral border and the spinous process of the fourth sacral segment forms the superior border.

The sacrococcygeal membrane forms the roof of the sacral hiatus (posterior sacrococcygeal ligament).

The spinal cord terminates at L1/2.

The cauda equina (lumbar and sacral nerve roots), which is covered by the dura, terminates at S2.

Hence, the dura extends to the lower border of S2 (not L4). The filum terminale terminates at the coccyx.

The complications associated with caudal anaesthesia have a low incidence and are certainly not common. However, an intraosseous injection of local anaesthetic can produce results similar to an intravascular injection, causing profound hypotension or cardiac arrest.

Other complications, which are also not commonly encountered include:

Urinary retention
Lower limb blockade
Dural puncture
Hypotension.

Question 11

Oxygen therapy

benefit in MI?
what level

CO
how benefit supplement oxygen

Answer 11

Physiological studies have made clear that there are potential adverse effects of oxygen therapy, and randomized trials have not demonstrated any significant benefits in terms of myocardial infarct size, patient haemodynamics, or patient symptoms. Some trials have identified a trigger for extended myocardial injury during uncomplicated acute myocardial infarction. There is strong evidence to avoid supplemental oxygen therapy in patients with uncomplicated acute myocardial infarction if the peripheral oxygen saturation is 93% breathing air.

Carbon monoxide (CO) has approximately 230 times the affinity for haemoglobin compared with oxygen. Once bound to haemoglobin oxygen itself is prevented from binding. This causes a shift of the oxygen-haemoglobin dissociation curve to the left resulting in a combination of anaemic and an element of histotoxic hypoxia. The latter is caused by the inhibition of cytochrome A3 by CO. The half-life of CO breathing air is 320 minutes. Breathing 100% oxygen reduces the half-life to 80 minutes and is the treatment of choice until the CO levels normalise (<10%). Hyperbaric oxygen therapy (2.5 bar) further reduces the half-life of CO to 23 minutes.

Supplemental oxygen therapy is appropriate in patients presenting with histotoxic hypoxia or a sickling crisis.

Prior to availability of blood gases, a 24% Venturi mask at 2-3 L/min or 28% Venturi mask at 4 L/min or nasal cannulae at 1-2 L/min should be used and aim for an oxygen saturation of 88-92% for patients with risk factors for hypercapnia (e.g. COPD) but no prior history of respiratory acidosis.

Question 12

CV response to high cord trauma

Initial - sympathtic point of view

heart rate

blood volumes

what stag does autonomic hyperreflexia appear

Answer 12

The initial cardiovascular response to high cord trauma is a short-lived acute pressor response, due to massive sympathetic discharge, which can cause arrhythmias and myocardial dysfunction.

The loss of sympathetic tone causes a reduction in systemic vascular resistance (SVR), hypotension and venous pooling of blood.

The loss of sympathetic control to the myocardium (T2 - 5) results in bradycardia and an inability to increase contractility.

The onset of spinal shock with the risk of precipitating pulmonary oedema, demands the careful titration of intravenous fluids titrated against the central venous pressure or pulmonary artery occlusion pressure.

The presence of hypertension and arrhythmias in response to sometimes minor stimulation suggest the development of autonomic hyperreflexia. This may become apparent after 4-6 weeks when the spinal shock phase has receded.

Question 13

Magnesium

What type of ion

where is it mainly

what are its action

use in pet?

effects uterus?

side effects what level

how is it monitor clinic

Answer 13

Magnesium is largely an intracellular cation present mainly in bone and skeletal muscle.

Only 1% is in the extracellular fluid and normal plasma levels are 0.75 - 1.05 mmol/l.

Its effect can be described as antagonising the actions of calcium.

Magnesium sulphate is used in pre-eclampsia as an anticonvulsant but it also relaxes vascular smooth muscle, causing vasodilatation thus lowering the mean arterial blood pressure.

It is also an effective tocolytic drug helping to decrease uterine contractions. It acts at the neuromuscular junction decreasing acetylcholine release thus neuromuscular function is weakened.

Therapeutic plasma levels of magnesium are 2.0 - 3.5 mmol/l, but side effects may occur above 4.0 mmol/l.

Increasing plasma levels of magnesium cause deep tendon reflexes to be diminished gradually until they become absent. Thus tendon reflexes are frequently used as a bedside measurement of hypermagnesaemia.

Question 14

Cat sections

whent o act

Answer 14

Once a decision is made to deliver a baby by caesarean section, it should be carried out with an urgency that is appropriate to the risk to the baby and the safety of the mother.

The urgency of caesarean section has four categories:

Category 1 - A threat to maternal or fetal life
Category 2 - Maternal or fetal compromise that is not immediately life threatening
Category 3 - Requires early delivery, but not maternal or fetal compromise
Category 4 - Elective delivery, at a time convenient to mother and maternity staff.
Category 1 and 2 caesarean sections should be performed as quickly as possible after making the decision, particularly for category 1. A decision to delivery time of 30 minutes is currently being used for category 1 caesarean sections.

Category 2 caesarean sections should be performed in most situations within 75 minutes of making the decision.

The decisions taken for rapid delivery should take into account the condition of the woman and the unborn baby as may be detrimental in certain circumstances.

In the example above there is no evidence of fetal compromise yet (early fetal pulse decelerations and a pH of less than 7.25). Early fetal pulse decelerations are most likely to be due to compression of the fetal head by the uterus. These are not harmful to the fetus. Whenever possible a spinal anaesthetic is preferable to a general anaesthetic.

If the fetal scalp blood pH is more than 7.25, it might be prudent to repeat later and look for any deterioration. With fetal decelerations the mother should be given oxygen, maintained in a left lateral position and maintain adequate hydration and raise the possibility of a caesarean section.

Question 15

Thyroid disease

Causes prim hypoothyorid

hashimoto?

TSH In prim and secondary

Clin featurs

CVs ft
what can precip my coma

Answer 15

Hypothyroidism can be primary or secondary to hypothalamic or pituitary disorders.

The causes of primary hypothyroidism can be classified as follows

Impaired synthesis or release of thyroid hormones
Resistance to thyroid hormones
Destruction of the endocrine gland (surgery, radioactive iodine)
Autoimmune disease.
Hashimoto’s disease is an autoimmune disorder that causes primary hypothyroidism (not hypoparathyroidism).

The thyroid stimulating hormone (TSH) level is elevated in all cases of primary hypothyroidism (not reduced) and can be normal or low in secondary hypothyroidism.

The clinical features of hypothyroidism usually have an insidious onset, with females being more commonly affected than males.

The cardiovascular features include

Pericardial effusions
Bradycardia and
Electrocardiograph abnormalities (inversion or flattening of the T waves and low voltage complexes).
Myxoedema coma may be precipitated by anaesthetic agents, opiates, cold and infection, and may be the presenting feature of hypothyroidism.

Profound bradycardia, bradypnoea and hypothermia are common, which require urgent treatment with thyroxine.

Thyroxine can cause angina pectoris in patients with ischaemic heart disease or heart failure.

Question 16

Childs weight formula

Answer 16

Weight = (Age + 4) × 2

Question 17

Childs weight formula

Answer 17

Weight = (Age + 4) × 2

Question 18

PDPH mx

Answer 18

This patient is likely to have a post dural puncture headache (PDPH).

Conservative measures for the first 24 to 48 hours are considered the most appropriate initial management strategy. This is because more than 85% of PDPH resolve with conservative treatment.

Conservative measures include bed rest, intravenous hydration, caffeine supplementation, and analgesic medication. Obviously, bed rest in the supine position may improve the symptoms of PDPH, although there is no evidence for prevention or faster recovery. There is also no evidence to support the common practice of aggressive rehydration or epidural crystalloid infusions to prevent PDPH.

Patients who do not respond to conservative treatment within 24-48 hours require more aggressive interventions. An epidural blood patch is considered the most effective treatment for moderate and severe PDPH, with success rates of 61-98%.

Question 19

DVT - what signs

RFactors

what type of techniwur has been shown to recude indicdence dvtg

Answer 19

Patients with deep venous thrombosis (DVT) usually present with physical signs that are unreliable or non-specific, and frequently require investigation to confirm the diagnosis. Some calf vein thromboses can be asymptomatic.

Risk factors associated with DVT and pulmonary embolism (PE) include hypercoagulable states such as deficiencies of:

protein C
protein S
antithrombin III, and
plasminogen.

Other risk factors are:

malignancy
prolonged immobility
the oral contraceptive pill
pregnancy
obesity
previous DVT
varicose veins
polycythaemia
myocardial infarction
cardiac failure, and

connective tissue diseases.
Lumbar (not thoracic) epidurals and spinals have been associated with a reduced incidence of DVT. This has been attributed to the increased blood flow to the lower limbs, reduced venous stasis and reduced blood viscosity (from intravenous fluid

Question 20

Caudal block in kids

Answer 20

The most important safety aspect in performing a caudal block is choosing an appropriate volume, and therefore dose, of local anaesthetic to minimise the chance of local anaesthetic toxicity.

Performing a caudal in a child “awake” is not a viable option. It would have to be inserted following induction of anaesthesia having first placed the patient in the lateral position. The sacral hiatus is identified and, under strict asepsis, a needle is advanced at an angle of approximately 55-65° to the coronal plane at the apex of the sacrococcygeal membrane where loss of resistance is a reliable endpoint.

The needle can be adjusted to an angle of 10-20° and advanced a small distance (3-4 mm); there should be no resistance to its passage. The most common needle used is a 21-23FG. Before injecting local anaesthetic, the needle must be aspirated first because there is a small risk (1 in 2000) of perforating the dura or vascular puncture.

The alternative is to use a 22-gauge plastic cannula with removal of the stilette following perforation of the sacrococcygeal membrane and advancing only the blunter plastic cannula; this lessens the risk of intravascular perforation.

Stimulating the caudal and epidural spaces and eliciting an appropriate end motor response at an appropriate current strength helps in improving the safety efficacy of neural blockade. A 22G insulated needle is placed in the caudal canal, instead of a 22-G hypodermic needle, until a “pop” is felt. An electrical stimulation of 1-10 mA is applied. The correct needle placement elicits anal sphincter contractions (S2 to S4).

One advance in paediatric regional anaesthesia is the application of ultrasonography in identification of the caudal epidural space. It has been shown that application of ultrasound guidance increases the safety and efficacy of the block in children, preventing inadvertent dural puncture.

Question 21

In acute pulmonary embolism:

Embolectoym used?

when thrombolyiss
- does this have to be central

Heparin effect thrombolytic?

Answer 21

Embolectomies are rarely done nowadays due to the excellent results with thrombolysis.

Thrombolytic therapy is reserved for those with severely compromised circulation rather than hypoxaemia. It is equally effective when administered through either a peripheral vein or a pulmonary artery catheter.

Heparin reduces risk of further embolism (anticoagulant not a thrombolytic) and reduces pulmonary vasoconstriction.

A normal ECG does not exclude the diagnosis.

Question 22

Paeds
Tracheal bifurc angle
vs adults

tissues

type of blade

Answer 22

Anatomical differences between adults and children must be considered during intubation.

For instance the angle of tracheal bifurcation is greater and the main bronchi come off at the same angle in children, whereas in adults the right main bronchus is more vertical and therefore more prone to inadvertent intubation.

However, children have comparatively larger soft tissues, including a floppy epiglottis.

In paediatric intubation a straight bladed laryngoscope (that is, Wisconsin, Magill or Miller) is placed behind the epiglottis holding it in position, so that it may be lifted to expose the slightly more antero-caudal placed cords.

In adults a curved Macintosh blade, with the tip in the vallecula anterior to the epiglottis, is used.

Question 23

Complications of blood transfusions

Answer 23

omplications following blood transfusions can be early or late and may be classified as follows:

Immunological
Infective
Metabolic, or
Volume effects.
Haemolytic reactions may be early or late, for example, ABO incompatibility.

Haemosiderosis is a complication of iron overload secondary to chronic blood transfusions.

Consumption or dilution of clotting factors and platelets and disseminated intravascular coagulation (DIC) are also recognised complications.

An alkalosis may follow the metabolism of citrate (found in stored blood) to bicarbonate, but an acidosis is uncommon.

Hypocalcaemia (not hypercalcaemia) can be seen with rapid blood transfusions which may require intravenous calcium therapy.

Question 24

Awareness management steps by nap5

Answer 24

Following the 5th National Audit Project of the Royal College of Anaesthetists and The Association of Anaesthetists of Great Britain and Ireland (NAP5) on Anaesthetic Awareness under General Anaesthesia (AAGA) in 2014 a support pack was produced for guidance.

The NAP5 Awareness Support Pathway for AAGA has 3 stages:

Stage 1

The patient should be met as soon as possible, preferably with a more senior colleague. The patient’s account should be listened carefully and accept that the story is genuine. The interview should be conducted empathically and at some stage regret should be expressed. At this early stage, it might be prudent to refer the patient to a local clinical psychologist.

Stage 2

A possible cause of awareness should be sought using the NAP5 process. Bearing in mind the patient’s account the details on the anaesthetic and recovery charts should be reviewed along with the accounts of attendant staff. An independent review by a suitably experienced group would be appropriate at this point to provide an unbiased view.

Stage 3

Detecting the psychological impact in the first 24-hours and active follow-up at 2-weeks. If psychological impact persists at this stage a formal referral to the psychiatric services is recommended.

Question 25

Forced alkaline diuresis
used what drug poison

How does it work?

Do charged molecule easily diffused across membrane

What is the fluid regimen?

Answer 25

Forced alkaline diuresis may be used in poisoning or overdoses with acid drugs (not alkaline), for example, salicylates and barbiturates.

Forced acid diuresis is used in poisoning with alkaline drugs.

By manipulating the pH of the urine, the ionised fraction of a drug (not unionised) is trapped in the urine, which prevents its diffusion back into the blood.

Charged molecules poorly diffuse (not readily) across biological membranes.

The process involves infusing specific fluids at a rate of approximately 500 ml per hour, and requires monitoring of the central venous pressure, urine output, plasma electrolytes (particularly potassium), and blood gas analysis.

The following fluids are administered in rotation:

500ml of 1.26% sodium bicarbonate (not 200 ml of 8.4%)
500ml of 5% dextrose and
500ml of 0.9% sodium chloride.

Question 26

What happens when items with bacteria are wet

What is the commonest spread of infection in hospital route wise

What type of bacteria are known for aerosolisation spread

How do theatre envinonment combat infection

How effective is sterilisation

Answer 26

If an item of equipment is contaminated with bacteria, the number of bacteria will usually remain constant, or decline, if the item is dry. If the item is wet, some bacteria, for example, Pseudomonas, may multiply.

Person to person contact is a very common cause of infection spread in hospitals, which explains why scrupulous hygiene when moving between patients on an ITU is essential.

Aerosols caused by air-conditioning units are notorious for spreading Gram negative bacteria, for example, coliforms. Though not necessarily a hospital aquired infection Legionella can be spread in this way.

Theatre air systems generate a positive pressure compared to the surroundings (not subatmospheric). The positive pressure air is moved away from the patient and filtered, so that airborne infections are prevented from reaching the patient. The laminar flow used in orthopaedic theatre is the logical progression of this concept.

Sterilisation renders an article sterile and infection free and the process includes the destruction of bacterial spores.

Question 27

Problems with bic

generates what - which leads to what problems

Answer 27

The use of bicarbonate causes generation of carbon dioxide which diffuses rapidly into cells causing:

Worsening intracellular acidosis
Negative inotropy to ischaemic myocardium
Large osmotic load high in sodium to a failing circulation and brain, and
Leftward shift of the oxygen dissociation curve to the left.
The administration of bicarbonate is recommended only if the cardiac arrest is associated with tricyclic antidepressant overdose or hyperkalaemia.

The alkalis THAM and carbicarb are not routinely used for treating the acidosis associated with cardiopulmonary arrest.

Tham solution (tromethamine injection) is a sterile, non-pyrogenic 0.3 M solution of tromethamine, adjusted to a pH of approximately 8.6 with glacial acetic acid. It is administered by intravenous injection, by addition to ACD blood for priming cardiac bypass equipment and by injection into the ventricular cavity during cardiac arrest.

Carbicarb (Na2CO3 0.33 molar NaHCO3 0.33 molar), a mixture formulated to avoid the objections to sodium bicarbonate therapy, has been compared with 1 mol/L NaHCO3 and 1 mol/L NaCl in the treatment of mixed respiratory and metabolic acidosis (pH 7.17) produced by asphyxia in rats.

In clinically appropriate doses, intravenous NaHCO3 raised arterial pH only 0.03 unit, elevated arterial carbon dioxide pressure, and doubled lactate concentration.

Question 28

NAP3
Vertebral canal haematoma incidence haematoma

relative risk with various coagulopathy

Answer 28

Following the third National Audit Project (NAP3) conducted on behalf of the Royal College of Anaesthetists, the incidence of vertebral canal haematoma after neuraxial blockade was 0.85 per 100 000 (95% CI 0-1.8 per 100 000).

Whilst unquantifiable, the incidence of vertebral canal haematoma following neuraxial blockade in coagulopathic patients is likely to be higher. For that reason, a coagulopathy remains a relative contraindication for conducting a spinal or epidural and only performed by experienced personnel having weighed up the balance of risk.

The relative risk of performing central neuraxial blockade in obstetric patients are as follows:

Normal risk INR ≤ 1.4
Increased risk INR 1.4-1.7
High risk 1.7-2.0

The bleeding time is used to measure the primary phase of haemostasis, which involves platelet adherence the injured capillary wall, and subsequent platelet activation and aggregation. The bleeding time can be abnormal when the platelet numbers are low or the platelets are dysfunctional. An expansion of the circulation associated with pregnancy reduces the platelets count. A normal bleeding time is 1-9 minutes.

The threshold for thrombocytopenia varies from 150 ×109/L -100×109/L and levels between these thresholds are common in mothers at delivery. Provided that a low count is stable, maternal health is good, and there are normal fibrinogen levels, INR and APTT, then expert opinion is that neuroaxial blockade can be justified provided the platelet count is 50×109/L or above.

Normal values for a thromboelastography include:

Initiation phase (R): 4-8 min
Amplification (K): 1-4 min
Propagation (α-Angle): 47-74°
Maximal amplitude (MA): 55-73mm
Clot stability (LY) 30%: 0-8%
A Prolonged K/Reduced α-Angle indicates the presence of Fibrinogen deficiency (i.e. DIC).
The activated partial thromboplastin time (aPTT) is a test of clotting function that focuses on the ‘intrinsic’ and ‘common’ pathways of the in vitro coagulation cascade model. Coagulation factors and cofactors within each pathway integrate to generate a fibrin clot end-point, the time taken to form the clot being the aPTT. The reference range of the aPTT is 30-40 seconds.

A prolonged APTT can result from vitamin K deficiency, liver disease, disseminated intravascular coagulation and anticoagulant therapy with vitamin K antagonists, UFH, LMWH, fondaparinux, direct thrombin inhibitors, direct-FXa inhibitors.

Question 29

Left to right shunts in kids

Right to left shunts

Answer 29

The commonest examples of a left-to-right shunt are an atrial septal defect (ASD), ventricular septal defect (VSD) and patent ductus arteriosus (PDA).

Children with this defect are usually not cyanosed (providing there is no left ventricular failure or reversal of the shunt).

Fallot’s tetralogy is the commonest form of a right-to-left shunt and the children are cyanosed.

Eisenmenger’s syndrome occurs when there is reversal of the left-to-right shunt (to a right-to-left shunt), due to irreversible pulmonary vessel disease.

Question 30

Burns patient

catabolic state?

affect 60% burn on bmr

WHat type nursed - why

Bacterial translocation can occur when
why

enteral nutrition helps how

what can improve survival - diet composition

Answer 30

After suffering a thermal injury the patient rapidly becomes hypercatabolic, with an increased cardiac output and oxygen consumption.

Severe burn injuries are associated with a greater hypermetabolic response. With a 60% total body surface area burn the metabolic rate is about twice the normal rate (not four times greater).

Patients should be nursed in temperatures of at least 30°C to reduce energy expenditure (not cool environments). The resetting of hypothalamic thermoregulation results in a 1-2°C rise in core temperature. The burned area should be covered to reduce evaporative loss of fluids.

The barrier function of the intestine is lost immediately after a thermal injury, allowing the translocation of bacteria and endotoxins, which can occur within hours (not 24 hours after the burn).

Early enteral feeding preserves intestinal mucosal integrity and prevents translocation of microorganisms into the circulation. Enteral nutrition is associated with a marked attenuation of the hypermetabolic response to a burn injury (not parenteral nutrition).

High protein diets (with a calorie to nitrogen ratio of 100:1), may improve survival after a burn. Fifty per cent of the calories should be in the form of carbohydrate, 30% as lipids or fat and up to 20% as protein or amino acids.

Despite the associated risk of infection supplementary parenteral feeding may be required.

Question 31

causes seconadry brain injury

CPP determ by

Targ CPP

autoreg?

Answer 31

Primary brain injury is usually irreversible and occurs at the time of injury.

Causes of secondary brain injury include hypoperfusion, hypoxia and reperfusion injury.

The factors that determine the cerebral perfusion pressure (CPP) include the mean arterial blood pressure (not systolic blood pressure) and the intracranial pressure (ICP) as shown in the following equation: Cerebral perfusion pressure (CPP) = mean arterial pressure (MAP) - intracranial pressure (ICP).

The Brain Trauma Foundation (BTF) guidelines support a target CPP of 50-70mmmHg. A CPP above 70 mmHg is not associated with improved patient outcome and maintenance of CPP higher than 70 mmHg is associated with greater risk of acute respiratory distress syndrome (ARDS).

In severe traumatic brain injury the autoregulation of cerebral blood flow is lost.

Cerebral oxygen consumption should be minimised following head injury (not maximised).

Question 32

duration of time safe for neurxial block

Answer 32

Following the third National Audit Project (NAP3) conducted on behalf of the Royal College of Anaesthetists, the incidence of vertebral canal haematoma after neuraxial blockade was 0.85 per 100 000 (95% CI 0-1.8 per 100 000). Whilst unquantifiable, the incidence of vertebral canal haematoma following neuraxial blockade in coagulopathic patients is likely to be higher. For that reason, a coagulopathy remains a relative contraindication for conducting a spinal or epidural and only performed by experienced personnel having weighed up the balance of risk.

An acceptable time after the last dose of rivaroxaban (in a patient with a creatinine clearance of greater than 30mL/minute) to perform a block is 18 hours.

An acceptable time after the last dose of subcutaneous LMWH as prophylaxis to perform a block is 12 hours.

An acceptable time after the last dose of subcutaneous UFH as prophylaxis to perform a block is 4 hours.

An acceptable time after the last dose of thrombolytic therapy (streptokinase or alteplase) to perform a block is 10 days.

It is common practice to stop clopidogrel 7 days prior to surgery, particularly if a central neuraxial procedure is considered.

Question 33

Paeds fasting times

Answer 33

The Association of Paediatric Anaesthetists of Great Britain and Ireland, The European Society of Paediatric Anaesthetists and L’Association Des Anesthésistes‐Réanimateurs Pédiatriques d’Expression Française produced a consensus statement in April 2018 with revised starvation times in children prior to elective surgery.

Pulmonary aspiration is a rare event in children, with an incidence of 0.07%‐0.1%.

Provided there are no specific contraindications (e.g. gastro-oesophageal reflux, cerebral palsy) a liberal clear fluid fasting regime does not affect the incidence of pulmonary aspiration in children. With a 2‐hour clear fluids fasting policy, studies indicate that this translates into a much longer duration of fasting (6‐7 hours), which is clearly undesirable.

These prolonged periods of fasting in children can increase thirst and irritability and can lead to other adverse physiological and metabolic effects.

Clear fluids are defined as water, clear (nonopaque) fruit juice or squash/cordial, ready diluted drinks, and non-fizzy sports drinks.

For non‐thickened, non‐carbonated drinks the starting point would be 3 mL/kg based on estimated weight or banding according to age. This would mean 1‐ 5‐year olds are allowed up to 55 mL, 6‐12 years up to 140 mL, and greater than 12 years up to 250 mL. This banding formula avoids the need to wait for a current weight (if it is unknown) that could delay the offer of an appropriate volume.

The preoperative fasting for elective procedures for children aged 0-16 years of age are as follows:

Solid food/formula milk - 6 hours
Breast milk - 4 hours
Clear fluid - 1 hour

Question 34

mx desat trachy

Answer 34

The most immediate action is to administer 100% oxygen and then connect the tracheostomy to an anaesthetic breathing bag and attempt to manually support ventilation. These two manoeuvres will guarantee the delivery of 100% oxygen and enable the assessment of the patency of the airway and efficiency of breathing. Assessment of lung compliance, lung expansion and any abnormal auscultatory findings can quickly be established. An end-tidal CO2 monitor would be useful to determine whether the tracheostomy tube has been dislodged. The cardiovascular status (blood pressure/cardiac output) of the patient will be important at this stage, as a dramatic fall in pulmonary perfusion may be the primary cause.

If the patient fails to respond to these early simple measures then help should be called for, as the airway may need to be replaced if necessary, under general anaesthetic. In the interim it would be worth attempting to pass a suction tube down the tracheostomy tube to see whether a sputum plug or clot in the tube or lungs is the cause. Tracheostomy cuff herniation, kink or malalignment will need to be excluded. If it is established that the tracheostomy tube is the cause, then it should be replaced either via the stoma or via the oral route.

Question 35

ASA Classif

Answer 35

The American Society of Anesthesiologists (ASA) introduced a new classification of physical status for patients in 1963, which was published in Anesthesiology.

Five classes (not grades) were described and an E suffix indicated that the patient required an emergency operation (not elective).

The physical status of patients is classified as follows:

ASA 1 patients have no organic, biochemical, physiological or psychiatric disease
ASA 2 patients have mild to moderate systemic disease
ASA 3 patients have severe systemic disease that is not incapacitating
ASA 4 patients have severe incapacitating systemic disease that is a constant threat to life
ASA 5 patients are usually moribund and have little chance of survival but are submitted to surgery as a last resort (resuscitative effort).
ASA 6 patients are those who have been declared brain-dead and whose organs are being removed for donor purposes.

Question 36

Rise in ETCo2

causes

Answer 36

The patient is rebreathing expired carbon dioxide.

The two most likely causes are exhaustion of the soda lime and failure of the expiratory valve. A less likely cause is a leak in the inspiratory limb. If the expiratory valve is incompetent, increased inhaled and exhaled carbon dioxide levels may appear with a normal appearing capnogram.

If the inspiratory valve is incompetent the patient will exhale into both the inspiratory and expiratory limbs. The capnogram sometimes shows a characteristic slanted downstroke inspiratory phase (as the patient inhales carbon dioxide-containing gas from the inspiratory limb) and increased end-tidal carbon dioxide.

With a high fresh gas flow, even if the soda lime were exhausted it would be sufficient to prevent rebreathing. The difference in inspired and expired oxygen concentrations would not be as marked.

Respiratory obstruction and malignant hyperthermia are causes of hypercapnia but not rebreathing

Question 37

Mx traumatic haemorrhage
admin products

when FFP recomend

Is fib conc licensed in UK

Answer 37

In the context of traumatic haemorrhage, administration of red blood cells (RBCs) and fresh frozen plama (FFP) in a ratio of 1:1 should be used to replace fluid volume. Consider the administration of cryoprecipitate (two pools) and platelets (one adult therapeutic dose) until test results are available and bleeding is controlled. Once control is achieved, blood components should be administered as guided by testing at the earliest opportunity.

Fresh frozen plasma (FFP) is recommended in major haemorrhage when fibrinogen is less than 1 g/L or the prothrombin or activated partial prothromplastin time is greater than 1.5 times the laboratory norm. 15-30 ml/kg is the first line dose for FFP.

Fibrinogen concentrate is not licensed in the UK and has to be given on a named patient basis but has the benefit of not needing thawing.

Recent trauma research studies have demonstrated a benefit of tranexamic acid in patients bleeding due to trauma.

Calcium is a key co-factor in activating the coagulation cascade and may be depleted in major trauma (exacerbated by calcium ligands in blood products). To optimise clotting the calcium levels should be monitored and adjusted if needed.

Recombinant factor VIIa is not recommended in major trauma as there is a risk of arterial thrombosis and the manufacturers state that its safety and efficacy has not been established in major trauma.