anaesthetics Flashcards
how often before surgery should the oral contraceptive be stopped?
4 weeks prior
what is suxamethonium apnoea ? how is it managed
Autosomal dominant mutation, leading to a lack of specific acetylcholistenerase in the plasma which acts to break down suxamethonium which terminates its muscle relaxant effect.
managed with mechanical ventilation and observation in ITU until effects of suxamethonium wear off
what are the two categories of muscle relaxants used in anaesthetics? give examples of each
Depolarising muscle relaxants - suxamethonium
Non depolarising muscle relaxants - atracurium, vecuronium, pancuronium
which anaesthetic agent is best for haemodynamically unstable patients and why?
Ketamine as it preserves blood pressure and does not cause cardio suppression
which anaesthetic is the choice for rapid sequence induction?
sodium thiopentone
what is the complication of excess infusion of sodium chloride?
Hyper-chloraemic acidosis
what is a common complication after surgery involving the bowel ? what are its features? what blood marker should be checked? How is it managed?
Post-operative ileus - reduced bowel peristaltis resulting in pseudo-obstruction.
features :
abdominal distension, pain , nausea and vomiting, inability to flatus
deranged electrolytes
management -
NBM
NG tube if vomiting
IV fluids
total parenteral nutrition
what is the ASA classification?
I : normal healthy, non smoker + minimal alcohol
II : mild systemic : smoker, social alcohol, pregnancy, obesity ( BMI 30-40) , Well controlled DM/ HTN, mild lung disease
III : severe systemic illness : substantive functional limitations - poorly controlled DM, HTN, COPD , morbid obesity ( BMI > 40) , esrd W dialysis, history of > 3 months of MI, Cerebrovascular accidents
IV : constant threat to life - sepsis, ongoing ischaemia, MI <3 m
V : not expected to survive without operation
VI : declared brain dead patient who’s organs are being removed for donor purposes
oral fluids / fasting rules re surgery
fluids 2h before ( clear fluids) , 6h for solids/ non-clear liquids
mx of patients on insulin undergoing minor procedures
good glycaemic control - adjustment of usual insulin regime ( defined as HbA1C < 69)
in what circumstances should a VRII be used
more than one meal is to be missed
patients with poor glycaemic control
risk of renal injury - low eGFR/ contrast
metformin - day before surgery, day of surgery ( morning) and day of surgery ( afternoon)
before - normal
morning - od, bd : normal
afternoon - od bd normal
basically for metformin the only time u make any changes is when the medication is being taken TDS - in which case lunchtime dose is omitted
sulfonylureas - day before surgery, day of surgery ( morning) and day of surgery ( afternoon)
day before - normal
morning surgery - omit morning dose , take evening dose if BD
afternoon surgery - omit everything regardless of od, bd
sglt-2 surgery rules
omit on day only
insulin surgery rules
once daily regimens - reduce dose by 20% ( before, day of)
twice daily regimens - half morning dose on day of surgery
what are the three phases of an operation
before induction of an anaesthesia - sign in
before incision of the skin - time out
before patient leaves the operating room- sign out
what is the checklist confirmed before proceeding with an operation
Patient has confirmed: Site, identity, procedure, consent
Site is marked
Anaesthesia safety check completed
Pulse oximeter is on patient and functioning
Does the patient have a known allergy?
Is there a difficult airway/aspiration risk?
Is there a risk of > 500ml blood loss (7ml/kg in children)?
Abdominal pain, bloating and vomiting following bowel surgery
postoperative ileus
what is the bowel prep required before a colonoscopy
laxatives the day before the examination
patients required not to eat 24h before colonoscopy
what medication should be prescribed prior to surgery for patients taking prednisolone
hydrocortisone supplementation
how should total parenteral nutrition be administered
central vein like subclavian line
which anaesthetic has inherent anti emetic properties
propofol
how do you manage severe anaemia prior to surgery
pre-operative blood transfusion
how is local anaesthetic toxicity managed
IV lipid emulsion
how long post total hip replacement should low molecular weight heparin be commenced
6-12 hours after surgery
what is the action of lidocaine
blocking of sodium channels
what is a cause of AF following gi surgery
anastomotic leak - presenting about 5 days post op
mx of anastomotic leak
back to theate
when should the following feeding options be used
ng feeding
naso jejunal
pec
parenteral
ng feeding - impaired swallow, c/ i in head injury
naso-jejunal feeding - avoids aspiration, safe post oesophagogastric surgery
feeding jejunostomy - long term feeding, post upper GI surgery
percutaneous endoscopic gastrotomy - in patients who cannot undergo endoscopy
total parenteral nutritional - enteral feeding c/i
what are the adverse effects of depolarising anaesthetics
malignant hyperthermia
hyperkalaemia
what is malignant hyperthermia , how is managed
serious recognised side effect of suxamethonium presenting with tachycardia, muscle rigidity , rhabdomyolysis, hyperthermia and arryhtmia - to be managed with IV dantrolene
what is the contraindication to nasopharyngeal airway
base of skull fracture
what are some consequences of impaired thermo-regulation during surgery
bleeding
intra operative hypothermia
how is an anastomotic leak diagnosed
abdominal ct
when is suxamethonium c/i
in trauma / burns patients as they increase the risk of hyperkalaemia
what is the action of non depolarising muscle relaxants ? how are they reversed
Competitive antagonist of nicotinic acetylcholine receptors
reversed using acetylcholinesterase inhibitors
what are the most common causes of post- operative fever?
day 1-2 : wind ( pneumonia, aspiration ,PE)
day 3-5 : water UTI
day 5-7 : wound surgical site infection
day 5 walking : dvt/ pe
anytime - drugs, transfusion reactions, sepsis, line contamination
what reverses the action of benzos
flumazenil
which anaesthetic is associated with hepatotoxicity
halothane
what is the s/e of long term total parenteral use
fatty liver and deranged LFT’s
in which procedures would addition of adrenaline to local anaesthetic be c/i
procedures with risk of digital ischaemia
in which procedures is group and save performed
Hysterectomy (simple), appendicectomy, thyroidectomy, elective lower segment caesarean section, laparoscopic cholecystectomy
Cross-match 2 units - which procedures
Salpingectomy for ruptured ectopic pregnancy, total hip replacement
Cross-match 4-6 units
Salpingectomy for ruptured ectopic pregnancy, total hip replacement
Cross-match 4-6 units
Total gastrectomy, oophorectomy, oesophagectomy
Elective AAA repair, cystectomy, hepatectomy
what are the symptoms of bile leak post cholecystectomy
RUQ tenderness
bilious fluid
what can cause hyponatraemic encephalopathy in paediatric patients
hypotonic agents (0.45%)
what can be done to minimize complications of poor BM control in patients requiring surgery
patient should be first on list
A 22-year-old fit and well male undergoes an emergency appendicectomy. He is given suxamethonium. An inflamed appendix is removed and the patient is returned to recovery. One hour post operatively the patient develops a tachycardia of 120 bpm and a temperature of 40 ºC. He has generalised muscular rigidity. What is the most likely diagnosis?
malignant hyperthermia
what intervention can reduce the risk of intra-abdominal adhesions
laparoscopy over open surgery
what are the causes of post-operative surgical site infections
enterobacter
staph aureus
which agent has moderate- strong analgesic properties
ketamine
which agent is contraindicated in patients with penetrating eye injuries or acute narrow angle glaucoma
suxamethonium - increases intraocular pressure
what are early causes of post-op pyrexia
blood transfusion
cellulitis
uti
physiological systemic inflammatory reaction
pulmonary etelectasis
0-5 days
what are the late causes of post op pyrexia
Venous thromboembolism
Pneumonia
Wound infection
Anastomotic leak
when are the following recommended pre-op
ecg
fbc
> 65 may need ECG before surgery
renal disease - fbc and ecg before intermediate surgery
diabetes- ecg before intermediate surgery
which positional manouvres to open the airway are recommended if there is concern about cervical spine injury
jaw thrust
which anaesthetic agent causes fasciculations
suxamethonium
which airway provides the poorest control against reflux of gastric contents ?
laryngeal mask
which airway is best to prevent high risk of reflux
endotracheal tube
what is the management of pre operative anticoagulation
stop warfarin 5 days before, switch to low molecular weight heparin and stop that before surgery
which medication can slow bone healing
Non steroidal anti inflammatory drugs
Steroids
Immunosupressive agents
Anti neoplastic drugs
what can be used to identify accidental oesophageal intubation
end tidal carbon dioxide monitoring
what is a complication of long term mechanical ventilation
trans-oesophageal fistula formation
Dropping sats following intubation → ?
oesophageal intubation
what airway is recommended in slow weaning
tracheostomy
which airway is used for day surgery procedures
laryngeal mask
what should be used with caution in patients with pneumothoraz
nitrous oxide
which anaesthetic can cause adrenal suppression
adomidate
which anaesthetic can cause laryngospasm
Thiopental
Volatile liquid anaesthetics
(isoflurane, desflurane, sevoflurane) s/e
malignant hyperthermia
what are hypertrophic scars caused by
excessive amounts of collagen
what are the advice for post-operative wound
Use sterile saline for wound cleansing up to 48 hours after surgery.
Advise patients that they may shower safely 48 hours after surgery.
Use tap water for wound cleansing after 48 hours if the surgical wound has separated or has been surgically opened to drain pus.
Intraosseous access is most commonly obtained at the
proximal tibia
