J de Beer

Content

• Classification• Diagnosis• Treatment• Anesthetic management

-preoperative-intraoperative

• Glycemic goals• Emergencies -Hyperosmolar nonketotic coma

-DKA -Hypoglycemia

Classification

Diagnosis

Treatment

Agents

• The secretagogues (sulphonylureas,meglitinides)-increase insulin availability

• The biguanides(metformin)-suppress excessive hepatic glucose release

• Thiazoledinediones-improves insulin sensitivity• a-glucosidase inhibitors-delay git glucose

absorption

Anesthetic managementPre-operative

• Look for end organ complications• Hx, exam• Special investigations;ECG, Urea, creat,

glucose, urinalysis• Atherosclerosis developes earlier and is more

widespread in the diabetic (IHD,Peripheral vascular disease,Cerebrovascular disease, renovascular disease)

Pre-op• Silent miocardial ischemia• Cardiomyopathy• Renal impairment: avoid nephrotoxins• Difficult laryngoscopy mobility of atlanto-occipital joint (stiff

joint syndrome)- prayer sign• Diabetic autonomic neuropathy

Risk of: intraop hypotension, periop cardioresp arrest, exaggerated intubation response, pulmonary aspiration secondary to gastroparesis

Tests: Beat-to-beat variation in HR during breathingHR response too valsalvaorthostatic changes in DBP and HR

Clinical signs of diabetic autonomic neuropathy

• Hypertension• Painless miocardial ischemia• Orthostatic hypotension• Lack of heart rate variability• Reduced heart rate response to atropine and propranolol• Resting tachycardia• Early satiety• Neurogenic bladder• Lack of sweating• Impotence

Signs of autonomic neuropathy

Pre-op

• Metoclopramide useful to increase gastric emptying• Try to attain best possible metabolic control• Adjustment of insulin may be required if poorly controlled• Discontinue biguanides (metformin) preoperatively

because of associated severe lactic acidosis during episodes of hypotension, poor perfusion or hypoxia

• Discontinue sulphonylureas, because they block myocardial k-ATP channels that are responsible for ischemia- and anaesthetic-induced preconditioning

• NPO times, sliding scales, first on list.

Insulin

• 2/3 of dose (NPH and regular) night before surgery

• 1/2 usual morning NPH dose on day of surgery and omit regular insulin on day of surgery

• Insulin pump: decrease overnight rate to 30%• On morning of surgery pump can be kept at

basal rate or replaced with continious insulin infusion at the same rate

intraoperative

• Anaesthetic plan acc to end organ complications• Consider invasive monitoring, awake intubation, RSI• Measure blood glucose before and after surgery. Hourly

measurements in high risk pt• Keep glucose between 6 and 10 mmol/l• Levels above 11.1 will lead to glycosuria and dehydration and inhibit

wound healing• 1 IU of insulin lowers blood glucose by1,3 to 1,6 mmol/l• Provide K and glucose together with insulin(5%dextrose in half

normal saline with 20 mmol/l KCL at 100ml/h• Potassium, phosphate, insulin, glucose as needed• Positioning-peripheral vascular disease or neuropathy

Glycemic goals

• Insulin resistance due to: inflammatory mediators, catabolic hormones, surgical trauma

• Hyperglycemia- poor perioperative outcomes-Van den Berghe et al-more strokes and deaths noted in intensive treatment group

Emergencies :Hyperosmolar nonketotic coma

• Remarkably high glucose levels• Profound dehydration• Enough endogenous insulin to prevent ketosis• Marked hyperosmolarity can lead to coma and

seizures• Increased plasma viscositythrombosis• Responds quickly to rehydration and small doses of

insulin• With rapid correction of hyperosmolarity, cerebral

edema is a risk

DKA

• Insufficient insulin to block metabolism of FFA• Acetoacetate and B-hydroxybutyrate• High anion gap metabolic acidosis• Degree of hyperglycemia does not correlate

with the severity of the acidosis• Dehydrated due to nausea and vomiting +

hyperglycemia induced osmotic diuresis

DKA clinical picture

DKA Rx

• Regular insulin, 10 IU iv bolus, followed by an insulin infusion nominally at bloodglucose/8 U/h

• Isotonic iv fluids as guided by vital signs and urine output; anticipate 4-10 l deficit

• When urine output > 0.5 ml/kg/h, give KCl, 10-40mEq/h (ECG monitoring if rate > 10 mEq/h)

• When serum glucose decreased to 13 mmol/l, add dextrose 5% at 100ml/h

• Consider sodium bicarbonate to correct pH< 6.9

Hypoglycemia

• Precise level at which symptoms develop is variable• Impossible to dx in clinically in unconscios pt• If awake: CNS changes ranging from light-headedness

to coma with seizures• Reflex catecholamine release with sympathetic

hyperactivity: tachycardia, lacrimation, diaphoresis, hypertension

• Misinterpreted as light anaesthesia• Symptomps obscured with b-blokker use and

advanced autonomic neuropathy

Hypoglycemia

• High index of suspicion and frequent blood glucose checks

• RX with 25 g of ivi dextrose( 1 amp of dextrose 50% in water) or 1 mg of imi glucagon

• Hypoglycemia is more likely to occur if insulin or sulphonylureas are given without supplemental glucose

• With renal insuficiency, the action of insulin and oral hypoglycemic agents is prolonged

End