- Discuss the anaesthetic management for an emergency operation having the problem of uncontrolled diabetes
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Discuss the anaesthetic management for an emergency operation having the problem of uncontrolled diabetes
Preoperative evaluation
- Investigations
- Electrocardiogram
- Urinalysis for detecting sugar and ketones
- Venous blood estimation of complete blood cell count, serum electrolytes, urea
- nitrogen, sugar, and ketones (serum osmolal ity i f available)
- Arterial blood gas analysis to determine acid–base status
- Evaluation should emphasize the cardiovascular, renal, neurologic, musculoskeletal and gastrointestinal systems
- Cardiovascular
- High suspicion on Myocardial ischemia and infarction
- Silent ischemia if autonomic neuropathy is present
- Stress testing should be considered
- Renal
- Control of hypertension
- Avoidance of nephrotoxins
- Preservation of renal blood flow
- Neurological
- Autonomic neuropathies may predisposes to dysrhythmias and intra operative hyotension
- Loss of compensatory sympathetic responses interferes with detection and treatment of hemodynamic insult
- Signs of autonomic neuropathy
- Lack of sweating
- Early satiety
- Orthostatic hypotension
- Gastric reflux
- Lack of change in pulse rate with deep inspiration
- Impotence and urinary symptoms of dysautonomic bladder
- Musculoskeletal
- Joint immobility caused by nonenymatic glycosylation of proteins and abnormal cross linking of collage
- If this involves the temporomandibular joint, atlantooccipital joint, or cervical spine, the resultant limitation of head and neck mobility may make endotracheal intubation difficult
- Gastrointestinal
- Increased risk of aspiration due to Gastroparesis
Preparation of the patient for anaesthesia and surgery
- Hydration
- Poor oral intake secondary to malaise and abdominal pain
- Vomiting
- Osmotic diuresis by glucosuria
- Insulin
- Infection and stress increases insulin requirements
- Insulin in small doses(5-10units IV) every hour or as continuous infusion at 1 to 2 units per hour using a pump
- Hourly blood and urine glucose and acetone measurements
- Antibiotics
Management of Insulin and glucose requirements on the day of surgery
- Glucose containing IV solutions can be avoided in Type 2 DM patients not taking insulin or OHA.
- Ringer's Lactate solution may predisposes to hyperglycemia(Lactate to glucose)
- Regular insulin on the basis of blood sugar determinations
- For extensive procedures and when the patient is not expected to resume oral intake for a few days, glucose should be given in the intravenous solution as a substrate for the increased metabolic demand, thereby providing a protein-sparing effect
- The blood sugar should be less than 250 mg per dL before the start of surgery
- In pediatirc patient, rapid-acting insulin may be given using a correction factor based on the “rule of 1500”
- Rule of 1500 : Divide 1,500 by the patient's total daily dose of insulin; this is the amount, in mg per dL, by which 1 unit of insulin is expected to lower the blood glucose. The goal should be to bring the blood glucose down to 150. (e.g., in someone taking 50 units of insulin daily, 1 unit of insulin is expected to reduce the blood glucose by 1,500/50 = 30 mg/dL.)
- Procedures >2 hours in duration, patients on insulin may benefit from simultaneous infusion of dextrose and insulin
- In pediatric patients, a solution of 10% dextrose and 0.5 normal saline at the appropriate maintenance rate is appropriate
- Accompanying insulin rate :
- 1 unit per 5 g dextrose in children 12 years or older
- 1 uni t per 3 g dextrose in children older than 12 years.
- In adults
- Dextrose can be given as an infusion providing 5 to 10 g per hour,
- Insulin at 1 unit per hour
Premedication
- 10 mg of metoclopramide given orally approximately 1 hour before surgery
Effect of anesthesia and surgery on insulin and glucose metabolism
- Insulin treatment started before surgery, along with a glucose infusion to maintain normoglycermia, results in lowering of cortisol levels immediately after surgery.
- Epidural block also reduces the release of stress hormones.
- Breaking the preoperative fasted state shortly before surgery with liquid oral carbohydrates has been shown to reduce postoperative insulin resistance
- Rapid-sequence induction/intubation with cricoid pressure should be employed to prevent aspiration for emergency surgery in the diabetic patient
- Close monitoring will be necessary to provide cardiovascular stability and adequate control of diabetes
- Blood glucose level >250 mg/dL should be treated with
- IV regular insulin. Small doses (up to 10 units) of insulin may be used reliably and effectively as single intravenous injections. In adults, a useful rule of thumb is that each unit of regular insulin lowers the blood sugar level by approximately 30 mg per dL.
- Although the half-life of intravenous insulin is short, hypoglycemia as late as 3 hours
- after an injection has been observed.
- Protocol
- No insulin or glucose on the day of surgery
- Partial-dose NPH(neutral protamine hagedorn) insulin on morning of surgery, 5% dextrose solution IV 125 mL/hr
- Constant IV infusion of insulin using special pumps, D5 W given
- IV bolus injection of regular insulin
- Subcutaneous regular insulin based on sliding scale
- Continuation of patient's insulin infusion pump
Hypoglycemia management
- Virtually impossible to differentiate hypoglycemic shock from other forms of shock unless supported by low blood glucose concentrations measurement
- Administration of glucose, which may be given as a bolus of 50% glucose, followed by a 10% dextrose-insulin infusion.
- Blood sugar level increases approximately 30 mg per dL for each 7.5-g bolus of dextrose in a 70-kg adult.
Control of diabetes in postoperative period
- Infusion of 10% dextrose-insulin-potassium, as determined by blood glucose and potassium every 4 to 6 hours, should be continued or regular insulin in divided doses
- Additional 20% of insulin may be required because infection is present.
Common post operative complications
- Poor diabetes control and infection
- Delayed wound healing
- Decreased leukocyte function
- Greater likelihood of brain damage in the setting of cardiorespiratory arrest.
- A higher incidence of cardiovascular and renal problems, in combination with autonomic neuropathy, can also result in postural hypotension and urinary retention
- Symptoms of diabetes plus random plasma glucose level >200 mg/dL
- Fasting plasma glucose level >126 mg/dL
- Two-hour plasma glucose level >200 mg/dL during oral glucose tolerance test
Etiopathogenesis
- Genetic susceptibility and an enviromental trigger
- Auto immune
- Viral infection
- Histopathologic studies
- Associaiton with Type 1 DM and autoimmune diseases such as Thyroiditis and myasthenia gravis
- At least 17 different genetic loci confer susceptibility to type 1 DM, including HLA-DR3 and HLA-DR4, located on the short arm of chromosome 6
- Genetically susceptible individual with an exposure to a virus that causes inflammation of the pancreatic islet cells and lymphocytic infiltration leads to Type 1 DM
- Type 2 DM results from a combination of insulin resistance, β-cell failure, and excessive hepatic glucose production
Type 1
- Pancreatic β-cell failure and ensuing insulin deficiency; before the age of 30yrs; insulin is required for control of glucose; autoimmune mechanism
- Milder form of disease
- Combination of insulin deficiency, insulin resistance and increased glucose production; can be managed with diet, exercise and oral hypoglycemic agents
- Obesity and older age are risk factors.
- Three important defects are seen in type 2 diabetes: (1) an increased rate of hepatic glucose release, (2) impaired basal and stimulated insulin secretion, and (3) inefficient use of glucose by peripheral tissues (i.e., insulin resistance)
- The increase in hepatic glucose release is caused by the reduction of insulin's normal inhibitory effects on the liver, as well as abnormalities in regulation of glucagon secretion.
- Beta cell insufficiency is also significant
- Type 2 diabetes is characterized by insulin resistance in skeletal muscle, adipose tissue, and the liver.
- Abnormal insulin molecule
- Circulating insulin antagonists, including counterregulatory hormones, free fatty acids, antiinsulin and insulin receptor antibodies, and cytokines
- Target tissue defects at insulin receptors and/or postreceptor sites.
- Insulin resistance is an inherited component of type 2 diabetes, with obesity and a sedentary lifestyle being acquired and contributing factors.
- Impaired glucose tolerance is associated with an increase in body weight, a decrease in insulin secretion, and a reduction in peripheral insulin action.
- Clinical diabetes is characterized by these same factors plus an increase in hepatic glucose production.
- Exhibit a compensatory hyperinsulinemia to maintain normoglycemia this leads to desensitization of target tissue
- Clinical and bio chemical characteristics of patients at risk of developing type 2 DM
- Combines insulin resistance with hypertension, dyslipidemia, a procoagulant state, and obesity, and is associated with premature atherosclerosis and subsequent cardiovascular disease.
- Diagnostic criteria
- At least three of the following:
- Fasting plasma glucose level ≥ 110 mg/dL
- Abdominal obesity (waist girth > 40 inches in men, 35 inches in women)
- Serum triglyceride level ≥ 150 mg/dL
- Serum high-density lipoprotein cholesterol level < 40 mg/dLin men, < 50 mg/dL in women
- Blood pressure ≥ 130/85 mm Hg
- Diagnostic criteria
- Symptoms of diabetes (polyuria, polydipsia, unexplained weight loss) plus a random plasma glucose concentration ≥ 200 mg/dL
- Fasting (no caloric intake for ≥ 8 hr) plasma glucose level ≥ 126 mg/dL
- 2-hr plasma glucose level > 200 mg/dL during an oral glucose tolerance test
Hb A1c test
- Measure of long-term glycemic control.
- Hemoglobin is nonenzymatically glycosylated by glucose, which freely crosses red blood cell membranes.
- The percentage of hemoglobin molecules participating in this reaction is proportional to the average plasma glucose concentration during the preceding 60 to 90 days.
- Normal range for Hb A1c is 4% to 6%.
- Increased risk of microvascular and macrovascular disease begins when the Hb A1c proportion is 6.5% or higher.
Sulphonylureas
- Tolbutamide(Rastinon) : Old age who get frequent episodes of hypoglycemia
- Glibenclamide(Daonil) and Glipizide(Glynase): Very potent and cheap
- Gliclazide(Diamicron): Prevent strokes and infarcts, but costly
- Glimepride(Glypride): Long acting, used in need of single dose only
- Chlorpropamide(Diabenase): Prolonged and fatal hypoglycaemia, not available now
- Metformin(Glyciphage): Safer,causes weight loss, can be used with combination of OHAs or Insulin. Adverse effect: Heart burn or diarrohoea
Glitazones
- Insulin sensitizers
- Should never be used alone
- Very costly
- Increase in weight
- Pedal edema and puffiness of face
- Hepatotoxicity, prohibits its use
- LFT to be done frequently
- Major advantage in patients whose blood sugar value is not controlled by Sulphonylureas + Metformin
- Diabetic ketoacidosis
- Hyperglycemic hyperosmolar syndrome
- Microvascular complications
- Macrovascualr complications
References :
http://icmr.nic.in/guidelines_diabetes/guide_diabetes.htm https://www.aace.com/files/aace_algorithm.pdf
