Peri- operative care Flashcards
How long should a pt not eat or drink dairy products for before surgery?
6hrs
How long before surgery should a pt stop drinking clear fluids?
2hrs
Why should a pt go into surgery with an empty stomach?
to reduce risk of aspiration when they put the pt under general anaesthetic and try to intubate
What causes the pt to reflux gastric contents when under general anaesthetic?
Many of the medications (propofol, sevoflurane, opioids) decrease lower oesophageal sphincter tone and the cough reflex is inhibited
In emergencies, how is risk of gastric reflex reduced?
NG tube and stomach drainage + rapid sequence induction (press on coracoid, minimal ventilation time)
What drugs need to be stopped prior to surgery? (4)
CHOWD Clopidogrel Hypoglycaemics Oral contraceptives Warfarin DOACs
How long before surgery does clopidogrel need to be stopped?
7 days before, cover with aspirin if minimal bleeding risk
Describe the management of a pts warfarin as they prepare for surgery (how long before should you stop it, what is INR needed, how do you restart)
- stop it 5 days before
- make sure INR <1.5 before op
- if INR now low enough night before, give PO Vit K
- restart at normal dose the evening/ day after surgery and continue with LMWH until INR in range as warfarin prothombotic initially
What should be given to a pt on warfarin who needs emergency surgery?
- check INR
- give Vit K and FFP as needed
How should DOACS be managed pre op? (for high/ low risk sugery and for good and bad renal function)
- If normal renal function and low risk procedure stop them 24 hrs before and restart 6-12 hrs after
- if higher risk, stop 48her before and start 48 hrs later
- check factor Xa levels if eGFR <50, for dabigatran check PT and APTT
- if abnormal renal function, seek guidance
- Give LMWH for VTE prophlaxis as normal
Should aspirin be stopped prior to surgery?
Not unless the surgical bleeding risk is very high, in which case stop 3 days before and start 7 days after. Give tranaxaemic acid in emergencies.
How should pts on dural antiplatelet therapy be managed pre op?
- if low bleeding risk surgery= continue both
- if high risk= defer surgery or continue with aspirin only
Why are oral contraceptives stopped pre op and how long before surgery should they be stopped?
As they increase VTE risk
Stop 4 weeks before
What prescriptions are need before most operations? (3)
- LMWH
- anti emolic stockings
- antibiotic prophylaxis
Give 3 contra indications of LMWH and for what surgeries may they not be given?
Acute bacterial endocarditis, major trauma, epidural anaesthesia, haemophilia, peptic ulcer (not absolute), recent cerebral haemorrhage
Dont give for most neck or endocrine surgery
What dose of dalteparin is given for medium risk surgeries?
2500 units, 6pm night before surgery and then every evening theyre in hospital for
What dose of dalteparin is given for higher risk surgery? (eg general, vascular or oethopaedic surgery)
- 5000 units if renal function is good
- on night before surgery and then thereafter
How long should LMWH be continued for, for hip and knee replacements?
hip= 28 days knee= 14 days
Why do you not give dalteparin before and until at least 4 hrs after a spinal epidural?
risk of spinal epidural haemoatoma which can cause cord compression, ischaemia and infarction
Which surgeries require a phosphate enema on the morning of surgery? (4)
- left hemicolectomy
- anterior resection
- sigmoid colectomy
- abdo peroneal resection
What bloods need to be done pre op?
- FBC (make sure not anaemic or infection)
- U&E (check renal function for clearance of anaesthetics and other drugs)
- INR (if on warfarin)
- Group and save (X match if hgiher risk surgery)
- LFTs (for metabolism of some drugs)
- clotting screen (pick up any clotting disorders)
What important anaesthetic complication should you ask the pt if they have a FHx or PMH of pre op?
malignant hyperthermia
What imaging may be requested pre op? (2)
- ECG (everyone- for baseline incase of post op ischaemia and to check for arrhythmias which may complicate anaesthetic)
- CXR (if resp illness, any cardio resp symptoms, smoking history or from TB endemic areas)
- any diagnostic/ or assessment images such as CT or MRI
Other than bloods and imaging, what other investigations may be requested pre op? (4)
- pregnancy test
- sickle cell test (if hx, fhx or afrocarribbean descent)
- MRSA swab nostils +/- perineum
- urinalysis (not routine)
What may increase insensible losses (water losses through sweating, respiration, faeces- normally accounts for 1L per day)
- febrile
- tachypnoeic
- diarrhoea
- sepsis
Why are pts with bowel obstruction very fluid deplete? What blood results will indicate dehydration in this context?
- 3rd space losses (increase osmitc gradient causes litres to be lost into peritoneum and bowel)
- vomiting
- will cause raised haematocrit and urea
what electrolyte changes does vomiting cause?
- Loss of H+ and Cl- from stomach
- causes metabolic alkalosis
- also hypokalaemia as kidneys excrete K+ and cells take up K+ to preserve intravascular H+
What is the daily requirement for water?
25ml/kg/day - 1.75 L in 70kg person
What are daily requirements for Na, K and glucose?
Na and K= 1mmol/kg/day (70mml in 70kg person)
Glucose= 50g/ day
What is the difference between hartmans and normal saline?
Hartmans has slightly less Na and Cl- and so has a slighly lower osmotic pressure
Hartmans has 5mmol/L K+
Outline a fluid maintenance regime for the 70kg pt with no significant comorbities?
- 500ml NS with 20mmol K+ over 8 hrs
- 1L 5% dextrose with 20mmol/l K+ over the next 8hrs
- 500ml 5% dextrose with 20mmol K+ over 8 hrs
What pt factors may mean you need to design a bespoke fluid regime?
- renal pts
- pts with cardiac impairment
- elderly, frail cachectic pts
What is the definition of a reduced urine output?
urine output <0.5ml/kg/hr
How should a reduced fluid output be managed?
- check the catheter is working properly// chart is filled in correctly
- A-E assessment
- give fluid challenge of 250 or 500ml over 15-30 mins and see how they respond
- give repeated challenges up to 2L or until BP/ output is restored
- If 2L given, seek expert help
What may cause a fluid deficit// reduced fluid output?
- third space losses (usualy bowel obstruction or pancreatitis)
- diuresis
- tachypnoeic
- febrile
- diarhhoea
- vomiting
What biochemical disturbance does diarrhoea cause? (3)
- loss of HCO3-, K+ and Na+ in stool
- leads to hyponaturaemia, hypokalaemia and acidosis
Why do you often get decreased urine output and sodium retention post op?
- sympathetic activation-> cortisol release -> raas activation -> retain Na+
- also retain K+ so DONT give K+ in 1st bag post op
When may an NG tube be used to feed?
- unable to take sufficient calories orally despite lots of encourangement
- dysfunction swallow
When may a pt be PEG fed (into stomach)
- oesophagus blocked or dysfunction
When is jejunal feeding (jejunostomy) used?
- stomach inaccessible, dysfunctional or outflow obstruction
When may parenteral nutrition be used?
jejunum inaccessible or intestinal failure
what screening tool is used to asses malnutrition?
- MUST tool
What can cause low albumin?
- chronic inflammation
- protein losing enteropathy
- proteinurea
- hepatic dysfunction
- NOT MALNOURISHMENT (very very rarely)
When can general and non general surgery start tolerating enteral feeding?
- non GI surgery= almost immediatly
- GI- within 24hrs
How can enterocutaneous. high fistula (jejunal) and lower fistula be managed?
- enterocutaneous (most heal spontaneously, some need surgery)
- high fistula (jejunal)- needs enteral or parenteral support
- lower fistula can be treated with low fibre diet
How are high output stomas managed?
- if long distance between the DJ flexure and the colostomy/ jejunostomy then then get parenteral feeding + supportive
- if not supportive only, reduce oral hypotonic fluid intake to 500ml/day, give loperamide and codeine, PPIs and low fibre diet (constipate them basically)
What may cause a high output stoma?
- gastric acid hyper secretion
- infection (pre stomal ileitis)
- bacterial overgrowth
How can pain be assesed?
- subjective: pain scale (mild, mod, severe)
- objective: tachycardia, tachypnoea, hypertension, sweating, flushing, unwilling to mobilise, agitation
Describe the WHO pain ladder
1: non opioid (parcetamol) + adjunct (ibuprofen)
2: weak opioid (codeine-> tramadol) + non opioid adjunct (naproxen, diclofenac)
3: stong opioid (oral morphine-oxycodone, IV morphine- methadone- diamorphine-> fentanyl) + non opioid
4: nerve blocks, epidurals
- Neuropathic pain better managed with amitryptyline or gabapentin/ pregablin
What are the cautions/ side effects of using NSAIDS? (5)
I GRAB
- Interactions (warfain)
- Gastric ulceration (add PPI if long term)
- Renal impairment
- Asthma (triggers 10% asthma pts)
- Bleeding risk (due to effect on platelet function)
give 4 side effects of opioids
- constipation (give laxative- lactulose)
- nausea (antiemetic- cyclizine)
- sedation
- confusion
- resp depression
- pruritis
- tolerance and dependence (rare)
What should you use instead of morphine in renal impairment?
Oxycodone or fentanyl
How long dose IV, oral and IM morphine take to work?
IV= 2-3 mins IM= 15 mins Oral= 20mins
How should t1 diabetics insulin be managed pre, intra and post op?
- on night before reduce SC inslulin by 1/3
- omit morning insulin and start IV variable rate insulin of 50mls NS and 50 units actrapid
- while nil by mouth (and intra op) give 5% dextrose at 125ml/hr and check BMS every 2 hrs
- continue until can eat and drink, give SC insulin 20 mins before meal and then stop IV infusion 30-60 mins after
How should a t2 diabetic on oral hypoglycaemics be managed perioperatively?
- stop metformin on morning of surgery and other hypoglycaemics 24 hrs before
- put on variable rate insulin and 125ml/hr dextrose same as for t1 if theyre poorly controlled or theyll miss >2 meals
Why is it important to monitor BMs intra op?
They cannot report symptoms of it and signs are hidden by anaesthetic. May get hypoglycaemic from starvation. It also helps avoid them getting ketoacidosis.
