ANAESTHETIC MANAGEMENT OFDIABETES MELLITUS Presented by DR. MD.RAYHAN REZA RONY MEDICAL OFFICER Dept. Of Anaesthesia,ShSMCH.
Diabetes mellitus Diabetes mellitus is characterized by impairment of carbohydrate metabolism caused by an absolute or relative deficiency of insulin or insulin responsiveness, which leads to hyperglycemia and glycosuria. The diagnosis is based on an elevated fasting plasma glucose(140mg/dl or 7.8mmol/l or more) & random blood glucose(200mg/dl or 11.1mmol/l or more)
Physiology of insulin Insulin Production 50 units/day controlled by plasma glucose level. Functions: ↑Glucose & Potassium entry into cells ↑Glycogen, protein & fatty acid synthesis ↓Gluconeogenesis, glycogenolysis,ketogenesis, lipolysis & protein catabolism Insulin promotes anabolism Insulin lack promotes catabolism.
Diagnosis(based on blood glucose level) FBS 126 mg/dl or 7.0mmol/l RBS 200mg/dl or 11.1mmol/lTYPE:4 Types: Type I Absolute insulin deficiency secondary to immune-mediated or idiopathic(IDDM) Type II Adult onset secondary to resistance/relative deficiency(NIDDM) Type III Specific types of diabetes mellitus secondary to genetic defects Type IV Gestational
Perioperative Response toSurgery and Anesthesia (I) Neuroendocrine stress response with release of counterregulatory hormones. 1. peripheral insulin resistance, 2. increased hepatic glucose production, 3. impaired insulin secretion, 4. fat and protein breakdown, 5. potential hyperglycemia and even ketosis in some cases.
Perioperative Response toSurgery and Anesthesia Fasting and volume depletion contribute to metabolic decompensation. Type I DM: Diabetic ketoacidosis may develop in the absence of severe hyperglycemia because of inadequate insulin availability during a time of increased demand Type 2 DM: Hyperglycemic hyperosmolar nonketotic states Infection Wound healing Local and epidural anesthesia: minimal effect
Diabetic Ketoacidosis(DKA) Insulin lack Catabolism of free fatty acid into ketone bodies (Acetoacetic acid & β hydoxybutyrate) which are weak acids. Identified by: ↑ plasma lactate(Lactic acidosis) No urine/ plasma ketone bodies. Precipitating factor Infection, trauma etc. C/F: Tachypnoea (to compensate met. Acidosis) Nausea, vomiting, abdominal pain- like acute abdomen Changes in sensorial
Treatment: Correction of hypovolumia: Total 5-6 Liters of Normal saline 1-2 L in first hour followed by 200-500 ml/hr in subsequent hrs To add 5 % DA when blood glucose drops to 250 mg/ dL Correction of Hyperglycemia & potassium Target: To reduce sugar by 75-100 mg/dl/Hour 10 units of soluble Insulin I/V in first hour by syringe pump If no response- double the dose. Sugar, K+ & ketone bodies to be measured hrly
Hyper osmolar Non KetoticComa(HONC) No ketone body formation due to some insulin Main feature *Hyperglycaemia diuresis dehydration hyperosmolarity (< 360 mosm/L) *Dehydration leads to renal failure, lactic acidosis & intravascular thrombosis. *Hyperosmolarity(>360mOsm/L) cerebral water balance change in mental status & seizures Treatment: Fluid, Insulin & potassium.
Hypoglycaemia: < 50 mg/ DL Excess insulin relative to CHO intake Brain depends on glucose for energy. Light headness, Confusion, convulsion & permanent Coma. Systemic features due to catecholamine release. e.g. diaphoresis, tachycardia & nervousness. GA masks the features Treatment: I/V glucose. 1 ml of 25% glucose raises 1 mg/DL
Diabetes and Surgery Surgery is a form of physical trauma It results in catabolism, increased metabolic rate, increased fat and protein breakdown, glucose intolerance and starvation. In a diabetic patient, the pre existing metabolic disturbances are exacerbated by surgery The type of diabetes, amount of insulin dose, diet or oral hypoglycaemic agents must be considered as this will change the overall management plan The risk of significant end-organ damage increases with the duration of diabetes, although the quality of glucose control is more important than the absolute time
Determinants of the management planfor diabetic patient 1. Type of DM 2. Treatment, diet, oral antidiabetic drugs, insulin 3. Metabolic status 4. Vascular status: cardiac, renal, cerebral 5. Surgery: Type: emergency or elective Minor or major procedure Type of anesthesia Post operative oral intake
Factors Adversely Affecting DiabeticControl Perioperatively Anxiety Starvation Anaesthetic drugs Infection Metabolic response to trauma Diseases underlying need for surgery Other drugs e.g. steroids
Perioperative considerationRelated To Anesthesia Cardiovascular Disease Renal dysfunction Peripheral and autonomic neuropathies Orthopedic Cause
Cardiovascular Disease ↑risk: hypertension, coronary artery disease, diastolic dysfunction, congestive heart failure, peripheral vascular disease and cerebrovascular disease, etc. Diabetes is not a contraindication to β- adrenergic blocker administration when such therapy is indicated
Management Most cardiac and antihypertensive drugs should be continued throughout the preoperative period except, aspirin, diuretics and anticoagulants History to determine effort tolerance, clinical examination for cardiac failure and an electrocardiogram in all patients. Echocardiography can help in assessing an ejection fraction in borderline cases
Renal Disease Renal dysfunction commonly develops Angiotensin converting enzyme inhibitors: ↓albuminuria and progression of renal dysfunction Consider renal function when selecting medications (avoiding potential nephrotoxic drugs) and modify dosage Management: Urea and electrolyte determination. Dipsticks urinalysis for proteinuria
Peripheral and autonomic neuropathies Neuropathy and vascular compromise: ↑risk for ischemia in pressure point while positioning diabetic patients Autonomic neuropathy: ↓compensatory cardiovascular response, ↑gastroparesis and predispose pulmonary aspiration Management History of postural dizziness, post gustatory sweating, nocturnal diarrhoea and impotence. Careful documentation of peripheral sensation
Orthopedic cause Stiff joint syndrome:chronic hyperglycemia->↑abnormal collagen cross-linking- > decreased joint mobility ->Decreased mobility in the temporomandibular and cervical spine joints. 30% cases of difficult intubation.. Management Clinical assessment of neck extension, examination of the small joints of the hand and a good evaluation of the ease of intubation
Pre-operative Assessment This is the most important step in the management of the diabetic patient Involves a thorough history and physical examination Review prior anaesthetic records to determine whether there were any difficulties with intubation or anaesthetics Lab investigations blood glucose - K+ BUN - creatinine ketones - proteinuria HbA1c (to assess how well controlled diabetes is)
Aims of peri-operativemanagement Avoid hypoglycaemia Avoid excessive hyperglycaemia Avoid loss of electrolytes (potassium, magnesium and phosphate) Prevent lipolysis and proteolysis H. J. Robertshaw1 and G. M. Hall. Diabetes mellitus: anesthetic management. Anaesthesia, 2006, 61, p1187–1190
Target glucose level Intravenous insulin therapy during the perioperative period, labor and delivery Targets: a. ICU patients < 110 mg/dL or b. Non-ICU patients < 110 mg/dL preprandial, < 180 mg/dL maximum c. Labor and Delivery patients < 100 mg/dL
Pre-Operative Management Admit as early as possible prior to surgery Avoid long-acting glucose lowering agents chlorpropamide –glibenclamide ultralente insulin Avoid metformin Closely monitor blood glucose levels 2 hourly for Type 1 4 hourly for type 2 Test urine every 8 hours for ketone Place first on morning operating list if possible Aim for a blood glucose of 5-10mmol/L
Intra-operative management Interval of blood glucose check: <2hrs Target of blood glucose: <180mg/dL Plasma K level: 4.0–4.5 mmol/L, check at least 24h Modify blood glucose: a. concurrently running separate infusions of insulin and glucose b. infusion of glucose mixed with insulin (with or without addedpotassium), ex: glucose-insulin-potassium solutions (the GIKsystem, or ‘Albert regimen’) ref: H. J. Robertshaw1 and G. M. Hall. Diabetes mellitus:anesthetic management. Anaesthesia, 2006, 61, p1187–1190
On the day of surgery It is preferable to take diabetic patients for surgery in the morning as first case. Normally the requirement of insulin is 0.3 U to metabolize 1gm of glucose. When FPG < 120 mg % no insulin is given except 5% glucose. When FPG 120- 160 mg % 5 % glucose with 5 units soluble insulin. For FPG 160- 200 mg % 5 % glucose with 8 U of soluble insulin.
Surgical Management of InsulinDependant Diabetes Mellitus Aim to keep blood glucose 5 to10mmol/L Pre-operative NBM for 6 hrs prior to surgery (4 hrs for clear fluids) Anti aspiration prophylaxis Initiate glucose/ potassium/ insulin regime after commencing NBM (check K+ as well) 500ml 10% glucose solution with 20mmol K+ at 1ml.kg-1.hr-1 connected to Y piece with insulin syringe Make up insulin syringe as 50 units insulin in 50 ml saline in a 50 ml syringe pump and run through Y piece with 10% glucose at between 1 to 5 u hr-1 (1 – 5 ml). Base on existing insulin regime Use sliding scale e.g. 1 u hr-1 if BG between 5 to 10mmole/l Hourly capillary glucose is measured until operation
Surgical Management of InsulinDependant Diabetes Mellitus Intra-operative Anaesthesia determined by patient physiology and surgical requirements Hourly glucose monitoring keep between 5-10 mmol/L Two hourly potassium monitoring keep between 3.5-4.5 mmol/L Set up additional IV for resuscitation fluids
Surgical Management of Insulin DependantDiabetes Mellitus Post-operative Continue Glucose/Potassium/Insulin regime until patient can take orally Oral medication with first meal Allow for pain resulting in increased insulin requirements
Surgical Management of Non Insulin Dependant Diabetes Mellitus Treat as insulin dependant if: poorly controlled (blood glucose >10 mmo/L) major surgery Pre-operative Biguanides must be stopped 48 hours before hand for fear of lactic acidosis NBM for 12 hours prior to operation Intra-operative Start i.v maintenance fluid 0.18% NaCl with glucose 4% Hourly capillary glucose is measured until operation
Surgical Management of Non InsulinDependant Diabetes Mellitus Hourly glucose monitoring Aim to keep within 5-10mmol/L or 90-180mg/dl if blood glucose >10 mmol/L, switch to treating as insulin dependant Post-operative Restart oral hypoglycaemic with first meal
Type of surgery Minor intermediate/majorPt. controlled by diet no specific precautions measure blood glucose 4 hourly ,if>12mmol/l or 216mg/dl start glucose-potassium-insulin sliding scale regimenpt controlled by oral Omit medication on morning Omit medication and monitorhypoglycemic drug of operation and start when blood glucose 1-2 hourly; if eating normally >12mmol/l start glucose- potassium-insulin sliding scale regimenPt controlled by insulin unless very minor procedure(omit insulin when nil by mouth)give glucose-potassium-insulin sliding scale regimen during surgery and until eating normally postoperatively.
GKI sliding scale regimen: Glucose-potassium-insulin sliding scale: infuse 10% glucose500ml + 10 mmol potassium chloride(KCl) at 100ml/hr .prepare a 50 ml syringe containing 50 units of actrapid(short acting)insulin in 50 ml normal saline and connect via a 3 way tap to a glucose infusion, adjust the rate of the syringe driver according to the following sliding scale Blood glucose(mmol/l) rate of syringe driver(ml/hr) <5 switch off 5-7 1 7-10 2 10-20 3 >20 4
Emergency surgery In emergency surgery it is deal to use intravenous insulin infusion. 37
GLUCOSE, FLUID, AND ELECTROLYTE MANAGEMENT Intravenous fluids1. Dextrose saline / normal saline is used if blood pressure is low or normal.2. If there is hypertension half normal saline or 5 % dextrose is given.3. For normal metabolism 50 gm glucose is required every 8 hours for energy and to avoid ketosis, to meet this demand at least 1000 cc 5 % glucose every 8 h will be required.4. In situations requiring fluid restriction 10 % dextrose can be infused instead of 5 % with double the dose of insulin.
GLUCOSE, FLUID, AND ELECTROLYTE MANAGEMENT 5 g of glucose per hour for basal energy requirements and toprevent hypoglycemia, ketosis, and protein breakdown duringsurgery. More glucose may be needed if conditions are very stressful. 1. Short procedures: 5% dextrose : 100 mL per hour 2. Longer procedures: 10% dextrose: 50 mL per hour 3. 20 or 50% through a central line if fluid restriction is critical.
GLUCOSE, FLUID, AND ELECTROLYTE MANAGEMENT Normal serum potassium level does not necessarily reflect a normal total body potassiumconcentration. Potassium into cells: Insulin and epinephrine Potassium out of cells: hyperosmolarity causes, acidosis. DM patient with normal renal function and serum potassium levels, 10 to 20 mEq per L of potassium should be added per liter of dextrose-containing fluid. More potassium is given if hypokalemia is present. In patients with hyperkalemia, potassium is not given unless the level falls into the normal range.
Practical aspects1. Whatever is the pattern of infusion, the blood sugar has to be checked every 1- 2 hours and the flow rate is adjusted.2. Intra and post operative potassium monitoring is done and corrected appropriately.3. A few hours after surgery there will be reduction in the insulin requirement as the elevated counter hormones due to surgical stress decline. 42
Other Considerations with Anaesthesia inDiabetic Patients Usual intra-operative monitoring record BP and pulse every 5 minutes watch skin colour and temp suspect hypoglycaemia if patient is cold and sweaty give IV glucose No contraindications to standard anaesthetic induction or inhalational agents If the patient is dehydrated then hypotension will occur and i.v. fluids will be needed
Our aim To make patients safe for surgery, for this we need an understanding team work between the surgeon, anesthesiologist and diabetologist. When the patient is under anesthesia the ideal is to have diabetic therapy supervised by a diabetic team where available. 44