Diabetes Emergencies and management of surgery

1. Diabetes Emergencies and management of surgery Simon Heller

2. 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 • < 30y omission of insulin • 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

3. Pathophysiology • lack of insulin + glucagon, adrenaline, cortisol leads to rising glucose levels from gluconeogenesis • lipolysis raises NEFA and glycerol. Liver oxidises NEFA to produce ketones from acetyl coA. • High glucose overcomes capacity of the kidney to reabsorb glucose, glycosuria inhibits water reabsorption plus losses of potassium, sodium, etc • 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. • A viscious spiral with renal loss of water, electrolytes, increasing glucose and worsening acidosis. • death within a few hours from severe acidosis and circulatory collapse.

4. Principles of DKA management • Restore circulating blood volume • Replace lost electrolytes • Return blood glucose towards normal while giving sufficient insulin to inhibit production of ketones Acidosis will correct itself if the above treatment is delivered appropriately

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

6. 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 2h, then 1 litre in 4h and 1 litre every 6h from then on. Reduce rates in the elderly or in cardiac disease • Be guided by urine output (aim for 60ml/h) • More rapid infusion rates increase the risk of serious complications especially respiratory distress syndrome.

7. Early Management • 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 6 omit and check in 2h 4-6 20mmol to each litre under 4 40mmol to each litre

8. Early management • Insulin Add 50 units of Actrapid insulin to 50 ml N saline in a syringe. Infuse intravenously, using a syringe driver and start rate at 6 units an hour. Check venous blood glucose after 2h-if blood glucose has not fallen, check pump is working and IV connections then increase rate to 12u/h.

9. Further management Measure blood glucose hourly Once blood glucose has fallen to <15mmol/l replace N saline with 5% dextrose given 1l over 6h Adjust dextrose to maintain infusion rate of 4u/h Typical insulin infusion rate Blood glucose (mmol/l);Infusion rate (units/h) <4 stop pump, check IV fluid 4-7 1 >7-11 2 >11-17 4 >17 6 Target blood glucose is between 11 and 17 mmol/l at 4u/h insulin Insulin levels need to remain high to inhibit ketogenesis

10. Other measures 1.Measure venous glucose, K+. Na+, bicarbonate every 2h for 6h, thereafter frequency depends upon clinical state. 2.Monitor ECG for potassium changes. 3.Consider urinary catheter if no urine passed after 2h 4.Consider n/g tube and aspiration if patient is comatose (only after airway is supported) 5.Give antibiotics only if there is evidence of infection. 6.Give oxygen if arterial pO2 less than 11kPa (80mmHg) 7.Give 10 units of Actrapid insulin IM if there is a delay in starting intravenous insulin.

11. 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.

12. Final comments The commonest mistakes in treatment of DKA are: 1. a failure to appreciate its severity (especially in the elderly in whom the mortality rate is over 50%) 2. trying to correct the abnormal metabolism too quickly.

13. Hyperosmolar Non-Ketotic Coma (HONK) Definition  Hyperglycaemia (blood glucose is usually over 50 mmol/l)  Hyperosmolality (usually over 350mosmoles/l)  Serum bicarbonate over 20mmol/l

14. Management Similar to DKA but : • Patients are usually elderly, have Type 2 diabetes and have decompensated slowly Mortality is high • Plasma sodium is usually over 150 mmol/l, but normal saline is still the fluid of choice • Consider low MWt heparin in the absence of contraindications, as dehydration is usually severe. 4. Most patients can eventually be managed with sulphonylureas or diet.

15. Problems of surgery • Issues: • Patients are usually fasted:-of major significance in Type 1 diabetes. Patients need basal insulin and without additional carbohydrate will develop hypoglycaemia.- little significance in Type 2 diabetes • Trauma of major surgery may provoke the release of stress hormones (eg adrenaline and cortisol)Increases insulin requirements in those with Type 1 diabetes and cause those with Type 2 diabetes to be insulin requiring temporarily. • Unconscious patients can’t complain of hypoglycaemic symptoms and can die or sustain irreversible brain damage from severe hypoglycaemia. • Poor and erratic absorption of sc insulin if peripheral vessels are shut down.

16. Principles of surgical management in diabetes • capillary glucose is measured regularly and accurately, recorded and acted upon. • most disasters have occurred because staff have either forgotten to measure glucose or very low values have been ignored or wrongly attributed to faulty meters

17. Surgical regimens-2 choices • Omission of anti-diabetic medication and regular monitoring-“fast/check” • short procedures in all patients • minor surgery (eg arthroscopy, D and C) • Separate glucose / insulin infusions • all emergency surgery • moderate or major surgery in Type 1 diabetes • major surgery in Type 2 diabetes

18. Omission of anti-diabetic medication and regular monitoring-“fast/check” • patient is placed early on operating list. • usual insulin injection or tablets omitted • measure capillary glucose hourly using meter. • give single dose of soluble insulin (Actrapid), 6 units s.c., if blood glucose rises >17 mmol/l • if blood glucose continues to rise consider IV regimen • restart normal regimen when eating and drinking normally

19. Separate glucose / insulin infusions • place patient at end of list or in the afternoonto give time to reach target glucose (7–11 mmol/l) • glucose infusion - 500 ml 10% dextrose + 20 mmol KCl • give at a rate of 50 ml/h using pump • 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 as above

20. Frequently asked questions • How do I decide if a patient has Type 1 or Type 2 diabetes? • Should patients go first on the list? • Should I start an IV regimen the night before just to make sure that the blood glucose is controlled the next day? • 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?

21. Hypoglycaemia Definition • Blood glucose less than 3.5mmol/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).

22. Clinical Features • Sweating, tremor, palpitations, incoordination, 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.

23. Treatment Give oral glucose immediately, ideally in liquid form (as Lucozade). If oral administration is not possible choose from: 1. IM glucagon The treatment of choice  Give 0.5-1 mg;  It is ineffective in alcoholics as glycogen stores are depleted.  After recovery ensure that oral carbohydrate is taken.  If there is no response within 10 min give IV glucose. 2. IV glucose  20-30 ml of 50% dextrose into a large vein. Flush with saline  Failure to recover consciousness within 60 min indicates possible brain damage. Start IV of 10% dextrose and maintain blood glucose at around 11 mmol/l. Some patients recover after coma as long as 48h.