Factors that predispose the surgical patient to hypoglycemia include prolonged fasting, inadequate/delayed food intake, changing insulin sensitivity, variability in subcutaneous insulin absorption, and changing renal function (5,19,44,45). The danger of hypoglycemia may be increased because the signs and symptoms of neuroglycopenia are masked by sedatives, anesthetics, and cardiovascular medications (16). Signs of hypoglycemia (diaphoresis, tachycardia, arrhythmia, and hypertension) may be mistaken for inadequate levels of analgesia or anesthesia (31). Changes in mental status, including focal neurological symptoms, may persist for hours to days following even a single episode of severe neuroglycopenia.

Frequent blood glucose monitoring is the key to avoiding hypoglycemia. Although the optimal frequency of monitoring has not been determined, many experts recommend hourly blood glucose measurements during and immediately following major surgery (5,7,14,16). Less frequent monitoring (every 2-6 h) has been recommended following the return of metabolic stability (5,7). Diabetics with high insulin sensitivity and hypoglycemia unaware-ness should be monitored more closely. Unfortunately, many clinicians do not monitor glucose levels with the recommended frequency. Golden et al. studied 411 adult diabetics undergoing CABG surgery. Only six capillary blood glucose measurements were taken during the 36-h period following surgery. The mean blood glucose level exceeded 200 mg/dL in more than 75% of the patients and one patient experienced severe hypoglycemia (12). Other reports document a low frequency of blood glucose monitoring in the perioperative period (16,17,46).

Many experts recommend an infusion of glucose to minimize the risk of hypoglycemia (8,14,15,16). Approximately 100 to 125 g of exogenous glucose per day are required to meet the basal caloric needs of the surgical patient, prevent ketosis, and prevent excessive protein breakdown. The additional calories required in the post-operative period can be provided with an infusion of glucose averaging 1.2 to 2.4mg/kg/min (515g/h for an adult) (17,27,47)]. Higher rates of glucose infusion often exceed the body's ability to utilize glucose and cause hyperglycemia.

Anesthesiologists commonly infuse non-glucose containing fluids during surgery to avoid hyperglycemia. Withholding glucose has been justified by the high incidence of hyperglycemia and low incidence of hypoglycemia during surgery (31). Controlled studies are needed to more clearly define the clinical importance of exogenous glucose (and other nutrients) during and after major surgery. Intravenous glucose should be used in the post-operative period rather than glucagon to treat hypoglycemia due to depleted hepatic glycogen stores.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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