Anaesthetics + Peri-operative care Flashcards
In which patients are nasopharyngeal airways ideal? In which patients are they contraindicated?
Ideal: Seizure
CI: Base of skull fracture- rare risk of inserting into cranial cavity
What are the pre-op fasting recommendatios?
Food >6h
Clear fluids >2h
Also applkies to pregnant women not in labour + diabetics
What can be used for emergency surgery in a non-pregnant adult who has not fasted?
Rapid sequence induction to reduce risk of gastro-oesophageal reflux
What does rapid sequence induction involve?
Optimal preoxygenation
Induction agent + suxamethonium
Application of cricoid force at the onset of unconsciousness.
How are diabetics treated with insulin with good glycaemic control managed during minor procedures?
Adjustment of usual insulin regimen
How are diabetics with surgery requiring a long asting period >1 missed meal/ poorly controlled diabetics managed during surgery?
Variable rate IV insulin infusion
How are most diabetics taking oral drugs managed for surgery?
Manipulating medication on day of surgery
Give 3 exceptions where diabetics on oral drugs should be managed with variable rate IV insulin infusion
> 1 meal to be missed
Poor glycaemic control
Risk of renal injury (low eGFR, contrast use)
How shold diabetics on metformin with a morning or afternoon op be managed?
Day prior: normal dose
OD-BD: normal
TD: omit lunchtime dose
How shold diabetics on sulfonylureas with a morning op be managed?
Day prior: normal dose
OD in AM: omit
BD: omit AM dose
How should diabetics on DPP IV inhibitors (-gliptins) or GLP-1 analogues (-tides) be managed for surgery?
Day prior: normal dose
AM or PM surgery: normal dose
How should diabetics on SGLT-2 inhibitors (-flozins) be managed for surgery?
Day prior: normal dose
AM or PM surgery: omit
How should diabetics on OD insulins e.g. Lantus, Levemir be managed for surgery?
Dar prior: reduce dose by 20%
AM or PM surgery: reduce dose by 20%
How should diabetics on BD biphasic or ultra-long acting insulins e.g. Novomix 30 be managed for surgery?
Day prior: normal dose
AM or PM surgery: halve usual AM dose, normal evening dose
How shold diabetics on sulfonylureas with a afternoon op be managed?
Day prior: normal dose
OD in AM: omit
BD: omit both doses
4 stages of wound healing
Haemostasis: mins-hours
Inflammation: 1-5d
Regeneration: 1-8w
Remodeling: 6w-1y
Which phase of wound healing is the longest?
Remodeling
Name a condition that impairs fibroblast synthetic function and immunity with detrimental effect in healing process
Jaundice
3 conditions that can compromise microvascular flow and impair healing
Vascular disease
Shock
Sepsis
List 4 drugs that impair wound healing
NSAIDs
Steroids
Immunosuppressive agents
Anti-neoplastic drugs
What is closure?
Delayed primary closure: anatomically precise closure that is delayed for a few days before granulation tissue becomes macroscopically evident
Secondary closure: spontaneous closure/ surgical closure after granulation tissue has formed
What are hypertrophic scars?
Abnormal, fibroproliferative scars with excess collagen
DONT progress beyond margins of original injury.
5 features of hypertrophic scars
Pink-red
Slightly raised
Uncomfortable + itchy
Occur within weeks of injury
Limited to confines of initiating wound
What usually causes hypertrophic scars?
Full thickness dermal injury
What are keloid scars?
Tumour-like lesions arising from connective tissue of a scar/ spontaneously
Extend beyond the margins of the original wound
Give 3 predisposing factors for keloid scars
Dark skin
Young adults
Sites: sternum, shoulder, neck, face
Management of keloid scars
Early: intra-lesional steroids e.g. Triamcinolone
Excision (risk further keloid scarring/ recurrence)
Give 5 features of keloid scars
Purplish-red
Firm, smooth + raised
Uncomfortable + itchy
Can occur years after injury + don’t regress
Grow beyond initiating wound area
Which abnormal form of scar contains nodules?
Hypertrophic scars
Describe the MOA of Suxamdthonium
Non-competitive (or depolarising) muscle relaxant
Induces prolonged depolarisation of skeletal muscle membrane
How does the use of suxamethonium manifest in a patient?
Fasciculations lasting a few seconds before profound paralysis
What is suxamethonium aka?
Succinylcholine
When is suxamethonium usually used/
Rapid sequence intubation in emergency settings due to fast onset + short duration of action
Give 2 adverse effects of suxamethonium
Malignant hyperthermia
Hyperkalaemia (norm transient)
In which patients is suxamethonium contraindicated? Why?
Penetrating eye injuries + acute closed angle glaucoma
It increases intra-ocular pressure
Name 4 competitive (non-depolarising) muscle relaxants
Atracurium
Tubcurarine
Vecuronium
Pancuronium
How do competitive (non depolarising) muscle relaxants work?
Competitive antagonism of acetylcholine at nicotinic receptors at NMJ
Name 1 adverse effect of competitive muscle relaxants
Hypotension
What drug can be used for reversal of competitive muscle relaxants?
Acetycholinesterase inhibitors e.g. Neostigmine
What is the MOA of Glycopyrrolate? How does this work?
Competitive antagonist of ACh at peripheral muscarinic receptors
Profound anti-secretory action
When is Glycopyrrolate used?
In conjunction with other anti-cholinesterases e.g. neostigmine to reverse muscle relaxation at end of surgery if required
What is postoperative ileus aka?
Paralytic ileus
What is the common cause of postoperative ileus?
Surgery involving the bowel
Reduced bowel peristalsis resulting in pseudo-obstruction
Give 5 S/S of postoperative ileus
Abdo distension/ bloating
Abdo pain
N+V
Inability to pass flatus
Inability to tolerate oral diet
What may contribute to development of post-operative ileus?
Deranged electrolytes
Check potassium, magnesium + phosphate
Describe management of post-op ileus
NBM initially, may progress to small sips clear fluid
NG tube if vomiting
IV fluids to maintain normovolaemia
TPN for prolonged/ severe cases
ASA 1
Normal healthy patient
Non-smoker
No/ minimal alcohol use
ASA 2
Mild systemic disease
w/o substantive functional limits
e.g. current smoker, social alcohol drinker, pregnancy, obesity (BMI 30-40), well-controlled DM/ HTN, mild lung disease
ASA 3
Severe systemic disease
Substantive funcitonal limitations
>,1 severe diseases
ASA 4
Severe systemic disease that is a constant threat to life
ASA 5
Moribund patient who is not expected to survive w/o the operation
ASA 6
Declared brain-dead patient whose organs are being removed for donor purposes
When is the gold standard for stopping the OCP prior to surgery under GA?
4w
Due to increased risk thromboembolism
No need to stop if LA
