FEBRUARY 1986, VOL. 43, NO 2 A O R N J O U R N A L

The Diabetic Patient REGULATING SERUM GLUCOSE LEVELS INTRAOPERATIVELY

Patricia Ball, RN

iabetes mellitus is a syndrome character- ized by glucose intolerance, large-vessel D disease, microvascular disease, and

neuropathy. It results from an interaction of hereditary and environmental factors. Whether the patient is type I (insulin-dependent or juvenile diabetic) or type I1 (noninsulin dependent), care is similar during a surgical procedure.

Because adult diabetic patients may appear physiologically older than their age, caution must be exercised with intraoperative administration of fluids; their cardiac function could be more impaired than age would indicate. For a rough approximation of the physiological age of a patient’s cardiovascular and renal status, add the duration of the diabetes to the patient’s chronologic age.’

Diabetic Complications

he diabetic is a higher risk patient for surgery and anesthesia than the nondiabetic T patient. Diabetic patient problems include

changes in the macrovascular, microvascular, and atherosclerotic processes; obesity; renal disorders; polyneuropathy; and glucose abnormalities.

Because of those complications, diabetic patients have earlier onset and increased severity of large vessel atherosclerosis. They also tend to develop thickening of basement membranes surrounding capillaries, a microvascular abnormality that is regional rather than general. It occurs most frequently in the peripheral circulation of the legs, but is also seen in the heart, kidneys, and nervous system.

Neuropathy is in the form of segmental injury to nerves resembling the thickening in capillary abnormalities. Numbness and tingling usually starts in the feet. Painless ulcerations may develop. Because of those symptoms, diabetic patients risk developing pressure sores during surgery. As a precaution, nurses must pad heels and other bony prominences.

Microvascular disease in diabetics can affect the kidneys; thus, monitoring fluid intake and output is essential to maintain adequate hydration without overload. If a fluid overload develops, it can lead to cardiac decompensation and heart failure.

Diabetic patients tolerate surgery and anesthesia best when their symptoms are controlled.2 High circulating blood glucose levels can impair the

Patrich Ball Rn! MA, CNOR, i s an OR nurse educator at Mt Camel Mercy Hospital, Detroit. She earned both her master? degree in education and her bachelor’s &gree in humanities from the University of Detroit. Her nursing diploma W(LF earned at the Mercy Schoo[ of Nursing, Detroit.

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The rise in blood glucose levels in response to stress comes from the release

of several hormones.

leukocytes’ function against infection. A subop- timal lymphocyte responsiveness makes the patient more susceptible to infection. Also, insulin deficiency may delay the development of antibody formation.

Electrolytes and Hormones

ven the diabetic patient who is clinically controlled is often potassium depleted E (hypokalemic) and may be deficient in

magnesium. Hypokalemia can cause decreased stroke volume and arrhythmias, and puts the patient at risk of cardiac arrest during general anesthesia. Magnesium appears to assist calcium and potassium cellular transfer, but its action is not fully understood. An isotonic saline infusion with potassium chloride and magnesium sulfate may be ordered the night before surgery if tests show the patient has lowered serum levels.

The diabetic with renal impairment may be hyperkalemic because the potassium balance is regulated by the kidneys. That can cause bradycardia leading to ventricular fibrillation and cardiac arrest with little warning other than electrocardiogram changes.

The stress and trauma of anesthesia and surgery, even the contemplation of surgery, can cause a metabolic stress response. That response is characterized by the release of hormones causing blood glucose levels to rise even in patients with normal levels. In the diabetic patient, a rise in blood glucose levels can result in severe hyperglycemia.

The rise in response to stress comes from the release of several hormones. One is glucagon, which is secreted by the alpha cells of the islets of Langerhans in the pancreas. Glucagon’s action is opposite that of insulin, which is secreted by the beta cells. Glucagon raises the blood glucose level by mobilizing glucose and augmenting glucose formation; whereas, insulin lowers the

blood glucose level by regulating and storing glucose. Epinephrine is secreted by the adrenal medulla during this time and has a glucagon-like effect.

The secretion of cortisol and growth hormones is stimulated. Cortisol, an antagonist of insulin, inhibits glucose breakdown and tissue uptake and enhances formation and release of glucose, thus raising blood glucose levels. Those levels can be raised further by growth hormones that work on fat catabolism and release glucose into the blood.

Surgery

0th diabetic and nondiabetic patients are resistant to insulin during this stress period. B In the diabetic, that means larger amounts

of insulin may be needed to “cover” glucose infusions. Any disproportion between the insulin dosage and the amount of glucose administered can induce episodes of hypoglycemh in the postoperative period when the stress of surgery and anesthesia has abated and there is no longer a resistance to circulating insulin.

The amount of glucose received during surgery appears to affect blood glucose levels in both the normal patient and the diabetic. That has been demonstrated in several studies using a glucose- controlled insulin infusion system or constant glucose monitoring system during surgery.

A University of Chicago study monitored blood glucose levels in 20 patients during the first two hours of surgery. Ten patients were insulin- dependent diabetics and 10 were nondiabetics with normal fasting and postprandial blood glucose values. Five from each group were given saline fluid replacement during surgery, and five were given glucose solutions. Cortisol, glucagon, and growth hormone levels were measured at the time of incision and monitored during surgery. No significant differences in the hormone levels were noted between the saline and glucose groups. But

FEBRUARY 1986, VOL. 43, NO 2 A O R N J O U R N A L

Using subcutaneous insulin and glucose/insulin fluid replacement often causes peaks

and valleys of hyperglycemia/hypoglycemia.

the study did find that the degree of hyperglycemia in both the diabetic and the nondiabetic was related to the rate of glucose infusion during surgery?

A second study, done at the University of Nancy, France, followed 22 randomly selected diabetic patients during surgery. Their blood glucose levels were constantly monitored during the perioperative period. The study found that acute increases in blood glucose levels were directly related to the amount and rate that glucose- containing solutes were infused!

Both studies demonstrate how difficult it is to maintain constant glycemia levels in diabetics receiving glucose infusions for fluid replacement and as vectors for anesthetic drug administration, even with concommitant doses of insulin. However, the studies showed that those receiving nonglucose solutions for fluid replacement and those whose blood glucose level was normal before surgery, often did not require insulin to maintain normal glycemia levels.

There are several alternative methods of approach used for the administration of fluids and insulin to the diabetic patient during surgery. Which method to use often depends on the personal preference of the anesthesiologist. These are the five common protocols that are in use.

Use IV glucose and administer one-third to one-half of the patient’s usual daily dose of insulin subcutaneously. Use IV glucose and give the patient’s usual insulin dose. Use nonglucose fluid replacement and give IV glucose mixed with regular insulin in a controlled infusion, (ie, 100 units of regular insulin per loo0 mL of 5% dextrose and water), and regulate the flow according to the blood glucose levels. Use a nonglucose fluid as replacement therapy and give a controlled insulin infusion or glucose infusion dependent on blood glucose levels.

Regular insulin is the only drug used for IV infusion. Whenever it is infused, 50 to 60 mL of the solution should be flushed through the tubing before patient infusion to fill the absorption potential of the tubing.

The University of Nancy study also compared the usual insulin protocols with feedback control using a constant glucose monitoring system? Results showed that using subcutaneous insulin and glucose/insulin fluid replacement often causes peaks and valleys of hyperglycemia/hypoglyce- mia. That could be caused by absorption of subcutaneous insulin from tissues being signifi- cantly influenced by variations in temperature, various anesthetic agents, and/or any blood volume deficit.

When glucose solutions are used for fluid replacement, the glycemia levels rise according to the rate and amount of glucose infused, even when mixed with insulin. When nonglucose fluid replacement was administered with controlled insulin and glucose according to blood glucose levels, the patient’s blood glucose could be stabilized.

Here is an example of a controlled insulin/ glucose infusion: 5% dextrose and water infused at 50 mL per hour; nonglucose solutions used for fluid replacement and vectors for drug administering; and regular insulin infusions piggybacked into the nonglucose solution. Blood glucose levels are measured every hour when insulin is not infusing, and every half hour with insulin infusing, and the insulin flow adjusted accordingly.

During the immediate postoperative phase, hypoglycemia can be a problem in the diabetic patient. Nurses should measure blood glucose levels when the patient arrives in the recovery room, and then every hour if infusing insulin. However, once the stress of surgery and anesthesia has abated, serum glucose levels are easily maintained when nonglucose fluids are used for

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fluid replacement. Achieving control of blood glucose levels is the

focus of treatment for diabetic patients. Until more studies are completed, the use of nonglucose fluids for fluid replacement, especially in the diabetic, appears to be a safe means of controlling hyperglycemia during surgery. 0

Ndes 1. M E Molitch, S Reichlin, “The care of the diabetic

patient during emergency surgery and postoperatively,” Orthopedic Clinics of North America 9 (July 1978)

2. A A Rossini, “Why control blood glucose levels?” Archives of Surgery 11 1 (March 1976) 229-223.

3. S S Schwartz et al, “Use of a glucose controlled insulin infusion system (artificial beta cell) to control diabetes during surgery,” Diabetologia 16 (1979) 157- 164.

4. P Drouin et al, “Use of biostator (R) glucose controlled insulin infusion system in 22 diabetic patients during surgery,” in Artificial Pancreas: Clinical Applications (Paris: Doin Editeurs, 1979) 199-21 9.

811-824.

5. Zbid.

Suggested reading Alberti, K et al. ‘‘Insulin delivery during surgery in

the diabetic patient.” Diabetes Care 5 (May-June

Biddle, C J; Hernandez, S. “Perioperative control of diabetes mellitus-revisited.” Journal of the American Association of Nurse Anesthetists 5 1 (April

Brunetti, P et al. “Therapeutical application of artificial beta-cell in surgery and obstetrics.” Hormone and Metabolic Research supp 8 (1979) 162-165.

Groer, M E Shekleton, M E. Basic Pathophysiology (St Louis: C V Mosby Co, 1979).

Hilton, Ann B. “Does diabetic control really make a difference?” The Canadian Nurse 78 (October 1982)

Horwitz, D L; Schwartz, S S. “Use of an artificial beta cell in surgery.” Hormone and Metabolic Research

Kerner, W et al. “Application of an artificial endocrine pancreas in the management of the diabetic surgical patient.” Hormone and Metabolic Research (1979)

Lynch, J A. “Preoperative and intraoperative insulin needs in diabetic patients.” American Association of Nurse Anesthetists Journal 52 (June 1984) 275- 279. The Merck Manual 13th edition (Rahway, NJ:

1982) 65-77.

1983) 138-140.

49-52.

(1979) 156-158.

159-161.

Merck, Sharp, and Dohm Research Laboratories, 1977).

Meyer, E et al. “Diabetic management by insulin infusion during major surgery.” American Journal of Surgery 137 (March 1979) 323-327.

Nemchik, Rita. “Diabetes today: A whole new world.” RhJ 45 (October 1982) 30-36.

Stroot, V R Lee, C A; Schaper, C A. Fluidr and Electrobtes: A Practical Approach 2nd edition (Philadelphia: Davis Co, 1977).

Genetic Traits of Suicide Studied Predisposition for severe depression and suicide may be passed from one generation to the next, according to a study of the Amish.

Sussex, MD, of the University of Miami School of Medicine, Miami, writing for the Aug 15 issue of the f o u m l of the American Medical Associa- tion, described their study on suicides. They chose a 100-year period in a community of Old Order Amish living in southeastern Pennsylvania.

This population was chosen based on two fac- tors: (1) marriage occurred within the commun- ity and (2) the Amish way of life does not have the economic and social stress often associated with suicide. Their isolation provided researchers opportunity to evaluate possible genetic factors linked to suicide.

“The suicides clustered in four primary pedi- grees, and the role of inheritance was suggested by the way in which suicides followed the distri- bution of affective disorders in these kinship lines,” the researchers stated, after interviewing family members.

The researchers found that 92% of the 26 sui- cides occurred in persons diagnosed with major affective disorders, and occurred in families with a higher incidence of manic depression, severe depression, and other affective disorders.

women. The mean age for men was 41 years, and for women, 55 years. The majority were married and had children.

Janice A. Egeland, PhD, and James N.

Of the 26 suicides, 21 were men and five were

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