Basic Sciences - Premedication Flashcards
Indications for pre-medication
Anxiolytics
Pre-emptive analgesia
Reduce acid aspiration risk
Continuing medication for chronic disease
When to administer temazepam for pre-medication
1 - 2 hours prior to surgery
Metabolism and excretion of temazepam
Metabolised in liver
Excreted by kidneys
Usual dosing of temazepam
10-20 mg
Usual dosing of lorazepam
1-2 mg
Goal of pre-medication in reflux disease in elective surgical patients
Increase gastric pH
Reduce gastric volume
Pre-medication options for acid aspiration risk
Antacids
PPIs / H2 receptor antagonist
Metoclopramide
Role of antacids
Increase stomach pH but no effect on volume
Duration of action of antacids
Limited duration of action
Therefore limited value during emergence when still aspiration risk
Role of PPIs / H2 antagonists
Increase gastric pH and reduce volume of gastric acid
Role of metoclopramide in premedication
Increases gastric emptying to reduce gastric volume
Potential side effects of NSAIDs
GI irritation
Asthma exacerbation
Renal dysfunction
Platelet function
NSAIDs effect on platelet function
Aspirin - irreversible platelet dysfunction
All other NSAIDs - only affect platelet function while their plasma concentrations are effective
Mechanism of action and side effects of NSAIDs description
Cyclo-oxygenase (COX and COX-2) inhibition (plays role in inflammatory response and prostaglandin production)
Reduces prostaglandin production
Therefore lose their protective effects on stomach and kidneys
Mechanism of action and side effects of NSAIDs flowchart
Classification of thromboprophylaxis risk
Thromboprophylaxis risk factors
Medications to omit prior to surgery, timing and reason why
ACEi / ARBs - stop morning of surgery, profound refractory hypotension during GA (continue all other antihypertensives / anti-anginals)
Warfarin - stopped 5-7 days prior with INR check and may need heparin bridging
Clopidogrel - stop 5-7 days prior
Oral contraceptive, ideally 6 weeks prior due to VTE risk
Options for diabetic insulin management perioperatively
VRII
Alberti regimen
Alberti regimen for diabetic insulin control perioperatively
Addition of actrapid insulin to intravenous dextrose fluids.
The amount of insulin added can be varied. The standard is 10% dextrose with ten units of actrapid and 1 g of potassium in 500 ml.
Blood sugar and potassium is measured every two hours and either add more insulin or omit insulin in next bag
Short acting oral hypoglycaemic agents
Gliclazide
Repaglinide
Long acting oral hypoglycaemic agents
Glibenclamide
Metformin
Glipizide
Rosiglitazone
