Diabetes Emergencies and management of surgery Diabetic Ketoacidosis

Diabetes Emergencies and management of surgery

Diabetic Ketoacidosis • Definition – Hyperglycaemia (use capillary sample but confirm with lab test) – Venous bicarbonate less than 15 mmol/l – Ketonaemia (if in doubt about cause of acidosis test urine or plasma with ketostix) • Causes – older age groups- infections – < 30 y omission of insulin

Diabetic Ketoacidosis Mortality: 5 -10% ? lower in specialist centres Causes • Elderly associated co-morbidity and late diagnosis • Young – severe DKA recognised late – a failure to monitor patients and follow guidelines – rare and poorly understood condition of cerebral oedema in children.

Pathophysiology (1) • lack of insulin and/or rising levels of glucagon, adrenaline, cortisol leads to rising glucose levels from gluconeogenesis • lipolysis raises NEFA and glycerol. Liver oxidises NEFA to form acetyl co. A and then ketone bodies • High glucose overcomes capacity of the kidney to reabsorb glucose, glycosuria inhibits water reabsorption and losses of potassium, sodium + other electrolytes

Pathophysiology (2) • Compensation for urinary losses by drinking maintains circulating blood volume • Rise in ketones and increasing acidaemia leads to anorexia and vomiting, a critical point • Circulating blood volume falls due to obligatory urinary losses from osmotic effect of urinary glucose

Pathophysiology (3) • A viscious spiral follows with renal loss of water, electrolytes, increasing glucose and worsening acidosis • Death within hours from severe acidosis and circulatory collapse

Principles of DKA management a potentially lethal condition, treatment should be started with 30 min of admission 1. Restore circulating blood volume 2. Replace lost electrolytes 3. Return blood glucose towards normal while giving sufficient insulin to inhibit hepatic production of ketones Acidosis will correct itself if the above treatment is delivered appropriately

Investigations Venous blood for: Urea and electrolytes Blood glucose Full blood count Venous bicarbonate Blood cultures • Consider: Arterial blood gases- only if you suspect hypoxia. Chest X-ray ECG (always do in anyone over 30)

EARLY MANAGEMENT • 1. IV Fluids – 1 litre of normal saline over the first hour. If there is hypotension give plasma volume expander (eg, haemaccel or blood) – Rate of fluid administration thereafter depends upon age and fitness of patient. – Typical rates are 1 litre in next 2 h, then 1 litre in 4 h and 1 litre every 6 h from then on. Reduce rates in the elderly or in cardiac disease – Be guided by urine output (>60 ml/h) – Rapid IV infusion rates increase the risk of serious complications especially respiratory distress syndrome.

Early Management 2. Potassium Serum potassium is often normal or high initially but total body potassium is low. Add potassium to the IV infusion only when first plasma potassium is known as follows: Serum potassium (mmol/l) Action over 5 omit and check in 2 h below 5 use 40 mmol/litre in pre-filled bag

Early Management 3. Insulin Add 50 units of Actrapid insulin to 50 ml N saline in a syringe. Start IV insulin at 0. 1 unit/kg/hr Check venous blood glucose after 2 h-if blood glucose has not fallen, check pump is working and IV connections

Further management • Measure blood glucose hourly • Start 10% Glucose 1 L 8 hourly once BG ≤ 14 mmol/L; continue sodium chloride 0. 9% separately if still volume deplete • Insulin infusion rates may need adjusting to keep blood glucose at an appropriate concentration • Target blood glucose is between 8 and 14 mmol/l Insulin levels need to remain high to inhibit ketogenesis

Other Measures 1. Refer to diabetes St. R or consultant on admission and to medical registrar on call 2. Consider urinary catheter if no urine passed after 2 hours of treatment 3. Consider nasogastric tube and aspiration if patient does not respond to commands 4. Monitor vital signs and chart Early Warning Score (SHEWS) 5. Commence prophylactic anticoagulation 6. When restarting usual insulin give first subcutaneous dose before intravenous insulin discontinued

Other Points Bicarbonate Generally not helpful and potentially dangerous. Consider only after discussion with senior colleagues Abdominal pain and tenderness common in DKA and serum amylase often high in the absence of pancreatitis. White cell counts as high as 30 x 109/L occur in the absence of infection.

Final comments The commonest mistakes in treatment of DKA are: 1. Failure to chase biochemistry and act on the results 2. Failure to appreciate its severity (especially in the elderly in whom the mortality rate is over 50%) 3. Trying to correct the abnormal metabolism too quickly.

Hyperosmolar Hyperglycaemic State (HHS) Hyperosmolar Non-Ketotic Coma (HONK) Definition Hypovolaemia • Hyperglycaemia (blood glucose is usually > 30 mmol/l) Osmolality >320 m. Osmol/kg (2 Na + glucose) All 3 must be present

Management Some important differences to DKA : 1. Patients are usually elderly, have Type 2 diabetes and have decompensated slowly, careful fluid replacement is key Mortality is high 2. Plasma sodium is usually over 150 mmol/l, but normal saline is still the fluid of choice 3. Low mol wt heparin unless C/I, as dehydration is usually severe and high risk of venous thrombosis 4. Most patients can eventually be managed with sulphonylureas or diet.

Principles of Treatment • Gradually and safely normalise serum osmolality by replacing fluid and electrolyte losses, and normalising blood glucose • Insulin not used routinely • Prevent complications such as arterial or venous thrombosis and foot ulceration • Avoid complications due to rapid fluid shifts such as central pontine myelinolysis and cerebral oedema • Treat underlying cause

Problems of surgery in diabetes Issues: – Patients are usually fasted: - of major significance in Type 1 diabetes. - little significance in Type 2 diabetes – Trauma of major surgery provoke release of stress hormones (eg adrenaline and cortisol) Increases insulin requirements in Type 1 diabetes and Type 2 diabetes. – Unconscious patients can’t complain of hypoglycaemic symptoms – Poor absorption of s/c insulin if peripheral vessels are shut down.

Principles of surgical management in diabetes § Capillary glucose is measured regularly and accurately, recorded and acted upon. § most disasters occur because § Inadequate monitoring of BG § Inappropriate action when faced with high/low BG

Surgical regimens-2 choices • Omission of anti-diabetic medication and regular monitoring-“fast/check” – Fasting < 18 hours, ie. eating by teatime – Hb. A 1 c* < 9. 0% – if type 1 Diabetes mellitus eating by lunchtime • Separate glucose / insulin infusions – Fasting > 18 hours or – Hb. A 1 c* > 9. 0% – Emergency

“fast/check” Put patients early on the list – Omit oral hypoglycaemics and insulin on day of surgery – Measure capillary blood glucose with meter 2 hourly – Restart usual diabetes treatment once patient – eating and drinking – • If blood glucose > 13 mmol/L before surgery – or rises to ≥ 15 mmol/L start IV insulin/glucose

Glucose / Insulin Infusions • place patient at end of list/afternoon to give time to reach target glucose (7– 11 mmol/l) • glucose infusion - 500 ml 10% dextrose + 20 mmol KCl (rate of 50 ml/h) • insulin infusion - soluble insulin 50 units, in 0. 9% saline, 50 ml, delivered by syringe driver • capillary blood measured hourly and insulin pump adjusted to maintain glucose

Frequently Asked Questions • How do I decide if a patient has Type 1/Type 2 DM? • Should patients go first on the list? • How do I decide when to stop the IV regimen and restart the usual treatment? • Should bedside capillary glucose values be backed up by venous laboratory measurements?

Hypoglycaemia Definition – Blood glucose less than 3. 5 mmol/l. • Causes 1. Patients with diabetes taking insulin or sulphonylureas (the commonest cause by far) 2. Drugs (Alcohol, aspirin poisoning in children) 3. Factitious overdose of insulin, sulphonylureas (especially medical or paramedical staff) 4. Insulin secreting tumours (eg insulinoma)

Clinical Features • Sweating, tremor, palpitations, in-coordination, parasthesiae, abnormal behaviour (aggression, fugue states), coma, seizures (focal or generalised). Hemiplegia can occur with a normal conscious level. • NB Consider in any diabetic who appears drunk.

Conscious / Fully Alert Fast acting carbohydrate • give one of: – Lucozade 100 mls – Fruit juice 200 mls – Cola/lemonade 150 mls – Original ribena (neat) 25 mls – Glucose tablets 5

Semiconscious or strict fluid restriction Glucogel • Apply small squirt left and right side of mouth between teeth and cheek and rub. • Repeat until 2 tubes finished

Unconscious / unable to take orally Give 50 mls 10% Glucose iv* quickly. Repeat dose until patient regains consciousness OR 250 mls given OR If no iv access give im glucagon (Glucagen)1 mg**

5 - 10 minutes, check blood glucose (BG), is it > 4 mmol/L? Yes Recovery Give starchy food e. g. bread/toast, 2 biscuits and milk or next meal if due No Conscious Repeat fast acting carbohydrate Unconscious 50 mls boluses 10% glucose iv until recovery or 250 mls given -give im glucagon 1 mg** if 250 mls -glucose already given -No recovery -10 -20% glucose infusions