Periop Flashcards
why is a pre operative assessment important
To highlight any potential problems that could be faced in surgery depending on co morbidities, allergies etc.
Identify high risk patients
Allows you to know which conditions need to be optimised before surgery and any additional precautions that need to be taken
Gives an opportunity for patient to express concerns/questions
Who conducts a pre op assessment and when?
anaesthetist:
elective surgery - 2 weeks before
urgent cases - day of surgery
emergency cases - simultaneously with resuscitation
Briefly what should you include in a pre op assessment?
full history including FHx
examination of CVS/resp and any relevant pathologies and mallampati score
ASA grade and identify high risk patients.
Investigations
review assessment with clinician
what should be covered in a history in a pre op assessment?
reason for surgery and site for op and type of procedure discussed with patient.
full history of presenting complaint i.e. reason for surgery
PMHx: comorbidities, previous surgeries and any problems (PONV, reactions). Specifically ask about:
- BP and exercise tolerance (judge risk of MI)
- COPD/asthma - ensure oxygenation will be good. triggers, control, hosp admissions, steroids?
- renal: blood loss and contrast can impair kidney function
- diabetes - what type? how is it managed? related problems?
- pregnant?
DHx: need to assess what needs to be stopped and inform patient.
allergies? medical and any at all because some food allergies are correlated to allergies to anaesthetic agents
FHx: any bad reactions to anaesthetics - often inherited e.g. malignant hyperpyrexia
SHx: drinking and alcohol - are they dependant i.e. withdrawal symptoms during surgery?
think about ethnicity - afrocaribean and undiagnosed sickle cell/keloid scars
what type of disease is malignant hyperpyrexia?
autosomal dominant
What is included in the examination of someone pre op?
A airways: check the mallampati score i.e. how well will they be intubated. Any loose teeth? Ask them to extend and laterally flex neck to assess range of movements.
B: breathing: resp rate, O2 sats, lungs clear?
C: circulation: BP, pulse, cap refil, heart sounds? warm/cold and clammy?
D: Glasgow coma scale/ ASA grade
what scoring system is used for predicting ease of intubation?
Mallampati score
grade 1: can see all of soft palate and uvula
grade 2: can see all of uvula
grade 3: can see base of uvula
grade 4: cant see any soft palate/uvula
what investigations would you want to do pre op?
depends on the type of operation (i.e. minor or major surgery) and the ASA grade of patient (i.e. how high risk they are. but some investigations include:
FBC : anaemic or thrombocytopenia U&Es: kidney function to assess how well they will tolerate fluid loss/ contrast LFTs Clotting MSRA swab urinalysis and preg test ECG CXR
when is a CXR or ECG indicated pre op ?
ECG: only if history of CVS disease or going for major surgery
CXR: lung disease, smoker, come back from country with high TB prevalence
what investigations are done in ASA 1 in a
a) minor
b) moderate
c) major surgery
minor - none
moderate - none
major: consider U and Es if at risk of AKI and consider ECG in those >65 if no ECG results in last 12 months
FBC in all major surgery ASA 1-3
what investigations are done in ASA 2 in a
a) minor
b) moderate
c) major surgery
minor = none moderate = consider ECG/ U and Es severe = FBC, ECG, U and Es
what investigations are done in ASA 3/4 in a
a) minor
b) moderate
c) major surgery
minor: consider ECG and U and Es
moderate: ECG and U and Es. Consider FBC, clotting, Lung function/ ABG
severe: FBC, U and Es, ECG. consider clotting , Lung function/ABG
what planning and preparation is done before surgery (after the pre op assessment)?
reassure patient - may be anxious
prepare - NBM for milk/foods 6hrs and water for 2 hours before
may need a bowel prep
Alter prescriptions
group and save/ Xmatch
referral after surgery - i.e. should they go to HDU, ITU or back to the ward
Discuss with patient the plan and let them ask questions.
pre medications
what is the difference between group and save and cross match? when is each required in regards to surgical patients?
group and save - patients blood is taken and tested for antigens and atypical Abs. Recommended when blood loss is not anticipated but as precaution.
cross match: patients blood is mixed with donors to check for any reaction. This is the second stage before blood transfusion can go ahead. this takes 45mins - 1 hour and is done prior to surgery if blood loss is anticipated.
Why is a patient made NBM before surgery?
there is risk of pulmonary aspiration which will lead to inflammation of the lungs (pneumonitis) and possibly infection (pneumonia)
some people have a slow absorption so a minimum of 6 hours NBM for food/milk is recommended.
in emergency surgery, patients will not have been NBM, how are the risks minimised by anaesthetist?
cricoid pressure applied during induction and intubation.
A cuffed endotracheal tube is then used. The cuff prevents aspirate into lungs.
what are the indications for ITU after surgery?
high ASA grade
long operating time
CVS, major vascular or intrathoracic surgery
emergency procedure
need for renal dialysis or intubation post op
list the drugs that should be stopped before surgery?
clopidogrel hypoglycaemics warfarin COCP and HRT ACEi and diuretics herbal medications
Why would you alter the following medications in surgery? How many days do they need to be stopped?
a) clopidogrel
b) aspirin and dipyramadole
c) hypoglycaemics
d) COCP/ HRT
clopidogrel is stopped 7 days before because of powerful antiplatelet affects and thus risk of bleeding
aspirin and dipyramidole do not need to be stopped because they have short half life so easily reversed and have a cerebrovascular benefit
hypoglycaemics (not insulin) stopped day before surgery - due to risk of hypoglycaemia during surgery. (long acting sulphonylureas stop 2-3 days before)
COCP/HRT - risk of DVT - stop 4 weeks before and commence 2 weeks later.
herbal medication can affect platelet function - stop 2 weeks before
why is metformin a problem during surgery? what precautions are taken?
firstly can lead to hypoglycaemia
secondly fluid loss/contrast can result in reduced kidney function which can result in poor clearance of metformin and the risk of lactic acidosis
therefore U and Es are checked 48-72 hours post op to see if it is safe to restart metformin
should warfarin be stopped during surgery?
yes - but further precautions may need to be taken depending on the reason the individual is on warfarin.
AF - stop warfarin 5 days pre op and check INR day before surgery
prosthetic heart valve: stop warfarin 5 days pre op and wait for INR to get to 2. Start IV unfractionated heparin and keep INR between 2-3. stop heparin 4 hours pre op and restart post op
previous DVT: stop warfarin 5 days pre op , high dose LMWH day before surgery
what INR is required for surgery?
<1.5
how can you adjust INR if it remains high the evening before surgery?
if there are 3 hours of more vitamin K can be given
either orally - a long time
or if shorter time IV infusion of 1-5mg vit K over 3 hours (cant go quicker due to risk of cardiac arrest)
if emergency and no time for Vit K infusion can instead give beriplex.
what is beriplex?
a solution of synthetic clotting factors:
factors 2,7,9, 10 and protein C
how are insulin and steroids altered for surgery?
subcutaneous insulin is switched to IV variable rate
corticosteroids should not be stopped (risk of adisonian crisis) but instead switch to IV hydrocortisone (5mg corticosteroids = 20mg IV hydrocortisone)
which drugs should be continued throughout surgery and why?
aspirin - cerebrovascular protection
statins - shown to reduce mortality
B blockers - suddenly stopping can result in rebound angina/MI
steroids - addisonian crisis
antihypertensives (except ACEi and diuretics)
transdermal GTN
thyroxine
why is it important that steroids are not stopped during surgery?
sudden ceasation can result in addisonian crisis (due to suppression of HPA axis) and the symptoms of this can often be mistaken for trauma in surgery
Antihypertensives are continued throughout surgery. if a patient becomes hypotensive, what can the anaesthetist do?
antihypertensives have a long half life so cant be reversed
however the anaesthetist can give nor-adrenaline to bring BP back up.
what drugs are usually started In surgery?
LMWH - except neck and endocrine surgery
Abx prophylaxis - esp orthopaedic, vascular or GI surgery
fluids
what DVT prophylactic measures are taken and how do they differ depending on surgery?
LMWH heparin (delteparin) given to all patients >20 yrs undergoing abdominal surgery - started
LMWH is given to all major GI, lower limb surgery for 28days pre-op plus TED stockings
high risk patients (OCP, previous DVT, obese, malignancy, amputes, pregnant) a larger dose of delteparin
laparoscopic procedures require delteparin
vascular other than nect require delteparin
do not give delteparin to neck or endocrine surgery
what Abx prophylaxis is given in colonic surgery?
gentamicin and metronidazole - due to gram negatives in bowel
Augmentin (penicillin) - for gram positives on skin and for laryngeal intubation
when are TED stocking (AES stockings) given?
all patients except vascular surgery or other contraindications e.g. Peripheral vascular disease, peripheral neuropathy, severe eczema, recent skin graft.
what is the difference between TED and intermittent pneumatic compression books?
TED are also known as anti-embolism stockings (AES) which are tight stocking to help flow of blood back up the legs.
intermittent pneumatic compression boots create a pressure wave to help move blood up. can be used in general surgery or vascular surgery depending on patient and anaesthetic preference.
which patients may need a bowel preparation? which preparations are used when?
patients undergoing colorectal surgery to reduce risk of infection.
upper abdo/small bowel and left hemicolectomy - no bowel prep required
right hemicolectomy/sigmoidocolectomy and abdoperineal resection - phosphate enema morning of surgery
anterior resection: 2 sachets of picolax day before surgery
what is the disadvantage of patients having bowel preparations?
fluid shift which can be harmful esp in those that are elderly or renal/cardiac problems and thus can increase post op recovery time.
list the 6 premedications used before anaesthesia
anxiolytics amnesia anti emetics antacids anti-autonomic analgesia
in premedication what anxiolytics can be given and why?
can give benzodiazepines (diazepam, lorazepam etc)
relax the patient
B blockers can also reduce anxiety
in premedication what drugs can allow amnesia?
lorazepam also allows a degree of anterograde amnesia
reduces post op distress
in premedication what anti-emetics can be given and why?
hycosine and anti-histamine can reduce anti-emetic effects of anaesthetics
metoclopramide increases gasrric emptying
reduce risk of N and V
in premedication what antiacids can be given and why?
ranitidine or omeprazole
Can help to reduce acidity in stomach which reduces N and V
esp if emergency situation and no time for NBM or opioids have delayed gastric emptying or hiatus hernia and at risk of regurgitation.
in premedication what anti autonomics can be given and why?
hycosine
anticholinergics can prevent the vasolytic effects on heart and reduce salivation
antiadrenergics - reduces tachycardia and hypertension
what is the problem with using hycosine as an anti-autonomic / anti emetic?
dry mouth and confusion post op
in premedication what analgesics can be given and why?
paracetamol, NSAIDS, opioids to reduce pain post op and reduce amount of anaesthetic agent required.
overall what is the use of pre-medications?
reduce risks e.g. aspiration
relax patient
reduce amount of anaesthetic needed
Define ASA
a) grade I
b) grade II
c) grade III
a) normal healthy patient
b) mild systemic disease
c) severe systemic disease
define ASA
a) grade IV
b) grade V
c) grade VI
d) grade E
a) severe systemic disease that is a constant threat to life
b) without surgery they will die
c) brain dead whose organs are being removed
E- emergency surgery
why are elderly patients considered as high risk? How can we minimise complications for these patients?
reduce immune and repair responses
more vulnerable to fluid losses and dehyrdration and malnutrition
usually comorbidities and polypharmacy
manage by involving different specialities
book high dependency unit bed
start feeding ASAP after surgery
why are pregnant patients considered as high risk? How can we minimise complications for these patients?
some of the anaesthetic agents could be teratogenic so need to find best drug regime
risk of preterm and induction of labour in 3rd trimester
increased risk of DVT - reduced by prophylaxis
reduced LOS tone and so more at risk of aspiration - reduced by less feeding
risk of supine hypotension (IVC compression by uterus)
list examples of high risk patients
Natural: elderly, pregnant
Disease: diabetes, CVS disease , COPD and asthma , renal/ hepatic impairment, obesity , recent stroke
Medications: , smoking, COCP emergency case, patients on steroids
associated with surgery: thyroid surgery, previous problems with anaesthetics
the COCP increases risk of VTE especially for what surgeries? in emergency cases how is this risk dealt with?
pelvis, lower limb and cancer
increased thromboprophylaxis period post op
why are patients on steroids considered as high risk? How can we minimise complications for these patients?
risk of addisonian crisis because of reduced stress response to surgery (because suppression of HPA) therefore may become hypoglycaemic, hypotensive and nausea and vomiting.
also steroids reduce immune responses so poor wound healing. also osteoporosis.
ensure you continue with IV hydrocortisone throughout surgery
give dextrose and fluids
how does a previous MI effect surgery? and what precautions are taken to reduce risks?
increases risk of another MI in surgery
put into HDU after surgery, antiplatelet medication is recommended
how can a murmur effect surgery and what precautions are taken to reduce this?
increases mortality rate in surgery
best to fix the murmur before surgery if possible
how can hypertension effect surgery and what precautions are taken to reduce this?
increases risk of IHD, MI, CVA, renal failure, LVF
so need to check all these - record BP, urine output (blood and protein), U and Es, glucose, ECG, ECHO, exercise stress test and angiography before and after
how does angina effect surgery and what precautions should be taken?
increases risk of MI, arrhythmias, valve disease, HTN, diabetes, PVD or CVD
do echo, stress test, ECG , angiography
how does smoking affect surgery? what precautions are taken to reduce these effects?
reduced immune responses, platelet aggregation, reduces oxygen carrying capacity (hypoxic risk to organs), reduced mucociliary escalator and reduced lung compliance
stop 6 weeks prior to surgery for best results but minimum of 7 days
post op - mobilise ASAP and thromboprophylaxis
how are asthmatic patients assessed and managed for surgery?
need to assess severity, exercise tolerance, triggers, medications, whether they smoke , medications and previous hospitalisation.
spirometry, ABG, chest xray
nebulisers and physio post op.
how are COPD patients assessed and managed for surgery?
get good history - severity, smoking history, frequent exacerbations? exercise tolerance? cor pulmonale? medication?
spiromentry, ABG, chest xrya
nebulisers and physio post op
how does the length of the procedure complicate surgery?
increases risk of PONV, local infection and paralytic ileus
how are people with hepatic and renal impairment managed for surgery?
more precaution to prevent hypovolaemia and hypotension
avoid nephrotoxin drugs
reduce drug dose due to reduced clearance
dialysis before surgery if needed.
how long should surgery be avoided for in those with recent stroke? what further precautions can be taken in patients with previous strokes?
6 weeks
control BP
thromboprophylaxis if ischaemic but not if haemorrhagic
what extra precautions should you take with obese patients before surgery?
detailed airway assessment - may require xray
detailed history of related problems and control
why is thyroid surgery high risk?
near the airways so risk of compression
risk of SVC obstruction
right largyngeal nerve risk of damage
what problems may someone have with anaesthesia?
anaphylaxis
suxamethonium apnoea
malignant hyperpyrexia
difficult intubation
what are the complications of anaemia during surgery?
anaemic patients bleed more - because blood is less viscous if less RBC
poor wound healing
therefore correct anaemia before surgery
why is a FBC important before surgery?
anaemia can complicate surgery
neutropenia can increase infection risk
also check if any bleeding disorders or FHx of bleeding disorders before surgery.
why is diabetes and surgery a problem?
problems associated with comorbidities:
- small vessels disease, renal impairment, peripheral neuropathy and increased risk of infection/ poor healing
- HTN and IHD
- obesity
medications can cause hypoglycaemia during surgery
ketoacidosis is associated with high morbidity and mortality so needs to be ruled out.
what investigations should be done in diabetics before surgery?
Check for co-morbidities FBC, U and Es, HbA1c and glucose urine - ketones and sugars ECG
need to know about normal management - insulin, diet and how well.