Surgery in patients with diabetes

Dr M A C K A NaserRegistrar/Medicine

Problems of diabetes during surgery

Fasting causes several problems in type I DM They need basal insulin to prevent

ketosis Develop hypoglycemia

Fating has little impact in type II, unless hypoglycemic agents are taken

Metabolic changes Surgery & the severity of surgery increases

the anti insulin hormones Increased adrenaline, ACTH, cortisol & GH

aggravate insulin def & resistance This increases catabolism with increased

glycogenolysis, proteolysis & lipolysis Gluconeogenesis is increased due to stress

From lactate, pyruvate, alanine & glutamate from liver & kidney

Resultant hyperglycaemia is more pronounced in diabetics than non diabetics

Metabolic changes Ketoacidosis

In the absence of insulin lipolysis is increased, leading to ketoacidosis

Plasma levels of FFA, glycerol & KB increase Metabolic acidosis can occur even in the presence of

near normal glucose levels All these metabolic changes are aggravated by some

types of anaesthesia High dose opiates Regional block

These changes cause increased insulin requirement in type I & possible requirement of insulin in type II

Principles of management Fundamental principle is monitor & record

capillary blood glucose regularly & act accordingly

Most problems occur due to Forgotten to measure glucose Very low values ingnored

Target glucose During surgery 7-11 mmol/l At normal levels – hypoglycaemia Above 11 mmol/l – increased UOP & dehydration

Principles of management Any other fluid (except the direct

dextrose) during surgical period should not contain glucose

Hartman’s solution is contraversial Lactate increases gluconeogenesis Blood glucose rise in type II

If fluid restriction is needed give glucose as 25% or 50% dextrose, via CVP line

Principles of management Electrolytes:

K levels should be monitored peri operatively K level varies due to

Insulin promotes K uptake by muscle, liver & adipose tissue

Dehydration causing K shift from IC to EC fluid Acidosis: exchange of H/K; conserving K by

kidney Most pts with normal renal function require

20mmol of K per litre of fluid

Emergency surgery Upto 5% of pts require urgent surgery at some time Danger:

Aggravation of DM Ketoacidosis (some times DKA may mimic acute abdomen)

Glycaemic control & acid base balance should be evaluated by Blood glucose Electrolytes Blood gas Urinary ketones

IV fluids should be given with pottasium & insulin as indicated

In ~60% of pts the acute abdomen resolves without laparotomy after correction of metabolic abnormalities

But autonomic neuropathy may mask symtpoms of real acute abdomen

Management strategies

Ommision of antidiabetics and careful monitoring

Separate glucose-insulin infusions GKI (glucose/K/insulin) infusion

Ommision of antidiabetics and careful monitoring

Suitable for: Short procedures (gastroscopy, dental extraction) –

all patients Minor procedures: arthroscopy, D&C – all patients Moderate procedures: hernia repair, hysterectomy –

in patients not prone to ketosis eg: type II pts Pt is placed early on the list Usual drugs omitted and blood glucose monitored

carefully with glucometer Single dose of soluble insulin given if RBG>17mmol/l If blood glucose continues to rise for 2hrs – IV insulin

regime should be considered Pts revert to normal regime when they can eat & drink

Separate glucose-insulin infusions Suitable for

All major surgeries Moderate or major surgery in type I DM Major surgery in type II DM

Pts should not be first on the list. Should be placed towards the end or afternoon

Blood glucose should be in the desirable range – 7-11mmol/l Infusion: 10% dextrose 500ml + KCl 10mmol – 100ml/hr Insulin infusion: 50u of S.Insulin in 50ml of 0.9% N.Saline by

a syringe driver and adjusted according to blood glucose Drop rates adjusted by syringe pump, not by naked eye Blood glucose monitored hourly

GKI (glucose/K/insulin) infusion Suitable for

Moderate or major surgery in type I DM All major surgery in type II

Infusion: 500ml of 10% dextrose + KCl 10mmol + 10 u of S.insulin given at rate of 100ml/min

Blood glucose every hour If successive 2 measures are 4-7mmol/l –

reduce insulin to 5u/500ml If 2 measures are 17mmol/l or more

increase insulin to 20u/500ml

Regimes for surgery in DM

Type of diabetes

Minor surgery

Moderatsurgery

Major surgery

Emergency

Type IAlways treated with insulin & ketosis prone

Fast & check

Glucose insulin or GKI

Glucose insulin or GKI

Glucose insulin

Type IIDiet/tablets/insulinNot prone to ketsosis

Fast & check

Fast & check

Glucose insulin or GKI

Glucose insulin

Post operative management

Once the patient is eating and drinking can return to usual regime

Type I pts must take the first dose of s/c insulin 60 minutes before terminating IV insulin