Peri-operative Care Flashcards
What patients fit into ASA grade 1?
A normal healthy patient. No smoking, minimal alcohol use.
Mortality: 0.1%
What patients fit into ASA grade 2?
Mild systemic disease. All patients older than 80 years are put into this category. Currently smoking. Social alcohol drinker. Obesity Well controlled diabetes Mild lung disease
Mortality: 0.2%
What patients fit into ASA grade 3?
Severe systemic disease. This from any cause that imposes a definite functional limitation on their activity - eg. chronic obstructive pulmonary disease.
Mortality: 1.8%
What patients fit into ASA grade 4?
Incapacitating systemic disease which is a constant threat to life.
Mortality: 7.8%
What patients fit into ASA grade 5?
A moribund patient unlikely to survive 24 hours with or without surgery.
Mortality: 9.4%
What pre-operative testing will ASA grade I adults need?
ECG if >40
U&Es if >60
What pre-operative testing will ASA grade II adults with cardiovascular disease need?
All require an ECG
Consider CXR if >40
FBC, U&Es and Urinalysis
What is malignant hyperpyrexia and how can it affect anaesthesia, and what is the immediate treatment?
Rare, autosomal dominant condition: on administration of certain anaesthetics (halothane, suxomethonium), CO2 levels, temperature and HR will increase, masseter spasm occurs and muscle cells are damaged.
Dantrolene is the immediate treatment
What is suxomethonium apnoea?
Suxomethonium is a muscle relaxant
The enzyme plasma cholinesterase is used to break down suxomethonium in the body, and the effects of the drug usually last 3-4 minutes.
In suxomethonium apnoea, the individual lacks the enzyme so the body remains paralysed for up to 8 hours, therefore the patient cannot breathe.
Treatment: continuous ventilation
Why can you not give volatile anaesthetics in a patient with Duchenne muscular dystrophy?
Risk of hyperkalaemic cardiac arrest or rhabdomyolysis
What is hypokalaemic periodic paralysis and how does this affect anaesthesia?
Hyperkalaemic periodic paralysis is autosomal dominant and is marked by episodes of flaccid weakness that resolve spontaneously.
There is an increased risk of pre and post operative paralysis as paralysis occurs whenever potassium falls.
What are the rules for preoperative fasting for children?
6 hours for solid food
2 hours for breast milk
1 hour for clear fluids
What are the rules for preoperative fasting for adults?
All healthy elective patients even with co-morbidities are allowed to drink clear fluids up until 2 hours of their surgery.
6 hours for solid food.
In patients with diabetes mellitus, how should pre-operative fasting be managed?
In those who will only miss one meal, do not give an insulin sliding scale and instead adjust their dosage of tablets.
In those who will miss more than one meal, offer a sliding scale insulin (give glargine/lantus alongside this and reduce by 20% after surgery)
In patients who miss more than one meal, the guideline is to offer a sliding scale insulin. However, what criteria need to be met for some patients to do this?
Patients who take metformin only or are on lifestyle modifications alone should only start a sliding scale if their capillary blood glucose is greater than 12mmol/L on two separate occasions.
In pre-operative patients with diabetes, what is the recommended first line substrate solution for a sliding scale insulin?
5% dextrose in 0.45% sodium chloride
and
0.5% KCL
How often should capillary blood glucose be measured in diabetic patients during surgery?
Hourly
What are the blood glucose targets in diabetic patients for the pre-operative and post-operative period?
6-10mmol/L in pre-operative, anaesthetised and sedated patients and those taking hypoglycaemic drugs (insulin, sulfonylureas)
Down to 3.5mmol/L is safe in AWAKE patients who are not taking hypoglycaemic drugs and are not on a sliding scale. In those who are on a sliding scale, the range is 6-12.
You can not operate on a patient if the HbA1c is >8.5%
What is the emergency treatment of hypoglycaemia in diabetics in the peri-operative period?
Glucogel and 20% dextrose
If a patient is hyperglycaemic pre-operatively, what do you do?
Check if capillary blood ketones are greater than 3. If >3, cancel surgery, if <3:
Type 1 diabetes: give S/C rapid acting insulin (NovoRapid). 1 unit will drop BG by 3mmol
Type 2 diabetes: give S/C rapid acting insulin (NovoRapid) 0.1unit/kg
How would you manage a known obstructive sleep apnoea patient pre-operatively?
Mild OSA (AHI 5-15): proceed routinely
Moderate OSA or above: refer for CPAP or BIPAP.
Patients on established CPAP should continue therapy and bring their device to hospital. OSA patients will usually require prolonged post-operative recovery in HDU.
How would you manage a suspected obstructive sleep apnoea patient pre-operatively?
Use the STOP-BANG questionnaire.
Those with scores >5:
With co-morbidities and/or undergoing major elective surgery: refer for polysomnography
Without co-morbidities and undergoing minor surgery: refer for pulse oximetry overnight alone
How would you monitor a OSA patient intra-operatively?
High risk patients: manage with senior anaesthetist and surgeon
Monitor: pulse oximetry, ECG, BP, invasive arterial monitoring
Airway: pre-oxygenate adequately. Intubate and ventilate.
If GA is mandatory with OSA patients, what anaesthetics should you give?
Short acting (desflurane, propofol) Limit opioid use
