Perioperative Care of Patientswith Diabetes

Celia M. Levesque, RN, MSN, NP-C, CNS-BC, BC-ADM, CDE

KEYWORDS

� Diabetes � Surgery � Diabetes medications � Hyperglycemia � Hypoglycemia

KEY POINTS

� Patients with diabetes undergo surgery more often than those without diabetes.

� Surgical patients with diabetes have a higher rate of morbidity and longer hospital staysthan patients without diabetes.

� An optimal perioperative plan of care for patients with diabetes is vital to reduce risk foracute complications secondary to poor glucose control.

INTRODUCTION

Diabetes is present in 8.3% of the United States population,1 but its prevalence insurgical patients is 15%–20%.2 Most of the surgical patients with diabetes are nothospitalized before arriving for surgery, but their postsurgical course is clearly affectedby the disease. Surgical patients with diabetes have a higher rate of morbidity andlonger hospital stays than patients without diabetes.3 Patients with diabetes alsohave a 50% higher risk of surgery-related mortality than those without diabetes.4

Surgical site infection rates are 2 to 3 times higher in patients with diabetes, andwound healing is often suboptimal.4 Although there are no published studies tosupport one perioperative diabetes management protocol over another, use of astandardized protocol has been found to be safe and effective.5 This article discussesthe effects of surgery on blood glucose, preoperative assessment of the patient withdiabetes, blood glucose targets during the perioperative period, and adjustment ofdiabetes medications during the perioperative period.

EFFECTS OF SURGERY ON BLOOD GLUCOSE

Surgery increases the release of catabolic hormones (epinephrine, glucagon, cortisol,and growth hormone) and inflammatory cytokines (interleukin-6 and tumor necrosis

Disclosure: The author has no relationship with a commercial company that has a directfinancial interest in the subject matter or materials discussed in the article or with a companymaking a competing product.Department of Endocrine Neoplasia and Hormonal Disorders, The University of Texas MDAnderson Cancer Center, PO Box 301402, Unit 1461, Houston, TX 77230-1402, USAE-mail address: clevesqu@mdanderson.org

Crit Care Nurs Clin N Am 25 (2013) 21–29http://dx.doi.org/10.1016/j.ccell.2012.11.007 ccnursing.theclinics.com0899-5885/13/$ – see front matter � 2013 Elsevier Inc. All rights reserved.

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factor-a) and decreases the release of anabolic hormones, especially insulin, whichleads to insulin resistance and hyperglycemia.3,4 Some patients without a history ofdiabetes will have transient hyperglycemia after surgery. Patients with type 1 diabetesdo not produce insulin and are unable to respond to the increased demand for insulinduring and after surgery. They are at high risk for diabetic ketoacidosis development ifinsulin is not replaced during the perioperative period. Patients with type 2 diabetesproduce variable amounts of insulin, have a relative insulin deficiency secondary toinsulin resistance, and have a reduced ability to respond to the increased demandfor insulin during and after surgery. Although patients with type 2 diabetes have a lowerrisk of diabetic ketoacidosis development compared with those with type 1 diabetes,they also need careful assessment and monitoring during the perioperative period.

ASSESSMENT BEFORE SURGERY

If the surgery is elective, a thorough assessment should be performed and a planimplemented to minimize comorbid risk factors. A complete diabetes history,including diabetes medication history, diet history, and review of the blood glucoselogbook, should be taken and a physical examination performed. Patients with dia-betes should be assessed for a history of poor glucose control, frequent or severehypoglycemia, hypoglycemia unawareness, diabetic ketoacidosis, hyperglycemichyperosmolar states, cardiovascular disease, cerebrovascular disease, hypertension,chronic kidney disease, peripheral vascular disease, autonomic neuropathy, andperipheral neuropathy. Elevated glycated hemoglobin (HbA1c) levels are associatedwith adverse surgical outcomes.3 The target HbA1c level for a patient depends onhis or her risk for hypoglycemia. Cardiac, renal, and peripheral nerve function shouldbe assessed. Preoperative testing should include electrocardiography and measure-ments of a metabolic panel, electrolytes, and HbA1c. The type of anesthesia, type ofsurgery (minor or major), the start and end times of surgery, the amount of time thepatient will be fasting, the type of diet that will be ordered after surgery, and thetype of intravenous fluids that will be administered all should be ascertained. If timeallows, the level of HbA1c should be reduced to less than 7% because this level isassociated with a lower incidence of postoperative infection.6

BLOOD GLUCOSE TARGET IN THE PERIOPERATIVE PERIOD

The blood glucose target during the perioperative period is a matter of debate. Vanden Berghe and colleagues7 found reductions in surgery-related morbidity andmortality in surgical intensive care patients randomly assigned to the group with thegoal of achieving blood glucose levels of 80–110 mg/dL compared with the conven-tional goal group who had the goal of achieving blood glucose levels of 180–200mg/dL. The NICE-SUGAR (Normoglycemia in Intensive Care Evaluation-SurvivalUsing Glucose Algorithm Regulation) study found that patients in the intensive armof the study (glucose goal of 81–108 mg/dL) had higher rates of severe hypoglycemiaand mortality than the control group (glucose goal of <180 mg/dL).8 The AmericanAssociation of Clinical Endocrinologists and the American Diabetes Association pub-lished a consensus statement regarding inpatient glycemic control, although it was notspecific to surgical patients with diabetes.9 They recommended that insulin therapy beinitiated in patients with blood glucose levels greater than 180 mg/dL, with a target ofmaintaining a glucose range of 140–180 mg/dL for most critically ill patients. For mostnon–critically ill patients, they recommended a premeal blood glucose target of lessthan 140 mg/dL and a random blood glucose target less than 180 mg/dL. They

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recommended scheduled subcutaneous insulin replacement with basal, nutritional,and correction components rather than sliding-scale insulin therapy.The Society for Ambulatory Anesthesia developed a consensus statement

regarding care for patients with diabetes undergoing ambulatory surgery.10 The orga-nization found insufficient data to recommend blood glucose or HbA1c levels abovewhich elective surgery should be postponed; however, the statement says thatsurgery should be postponed if the patient has complications of hyperglycemia,including dehydration, ketoacidosis, and hyperosmolar nonketotic states. They sug-gested maintaining an intraoperative blood glucose level of less than 180 mg/dL formost patients, but the goal level is dependent on factors such as the duration ofsurgery, invasiveness of the procedure, type of anesthesia, duration of fasting, anddiabetes medication regimen before the procedure. They recommended that patientswith a previous history of poorly controlled diabetes maintain their preoperative base-line values rather than try to normalize the blood glucose, because such patients havean altered counter-regulatory response, which leads to symptoms of hypoglycemiawhen the blood glucose level is normal and because acute reduction in blood glucosecan cause an oxidative stress response, which increases the risk of perioperativemorbidity and mortality.

ADJUSTMENT OF NONINSULIN DIABETES MEDICATIONS

If a patient is not taking any diabetes medications before surgery, blood glucose levelsshould be measured before and after surgery. Hyperglycemia can be treated withrapid- or short-acting insulin as needed. Taking sulfonylureas increases insulin secre-tion for 24 hours or more and can cause hypoglycemia. If a patient is taking a sulfonyl-urea before surgery and is eating normally, the drug can be administered the daybefore surgery. The dose may be reduced or omitted if the patient’s diet is restrictedthe day before surgery. Sulfonylureas should be omitted the day of surgery andrestarted when the patient is eating well.Meglitinides also increase insulin secretion but last for a shorter period. They can

cause hypoglycemia, although the risk is smaller than that arising from sulfonylureause. Meglitinides may be given with each meal the day before surgery but need tobe omitted on the day of surgery. Theymay be restarted once the patient is eating well.Thiazolidinediones do not cause insulin secretion and therefore do not cause hypo-

glycemia. They may be given the day before surgery but will be withheld while thepatient is prohibited from oral intake.Biguanides inhibit liver glucose production and augment peripheral glucose uptake.

They do not increase insulin secretion or, consequently, hypoglycemia; however, iflactic acidosis develops, biguanides may exacerbate the condition. Biguanides maybe given the day before surgery but should be withheld the day of surgery andrestarted when good renal function is verified after surgery and the patient is eating.Biguanides are not used in male patients with a creatinine level of 1.5 mg/dL or higher,female patients with a creatinine level of 1.4 mg/dL or higher, or patients with signifi-cant liver disease or heart failure.Other agents that should be withheld on the day of surgery are a-glycosidase inhib-

itors, incretin mimics, and dipeptidyl peptidase-4 inhibitors. Amylin agonists can beadministered on the day of surgery, but only with a meal. All these agents can beresumed once the patient is eating well. See Table 1 for oral diabetes medications,Table 2 for insulins, and Table 3 for noninsulin injectable medications and their impli-cations for surgery. Table 4 summarizes recommendations for the adjustment ofinjectable diabetes medications on the day before surgery.

Table 1Oral diabetes medications

Medication Names Generic (Trademark) Mechanism of Action Surgery Implication

Sulfonylureas: Glimepiride (Amaryl)Glipizide (Glucotrol, Glucotrol XL)Glyburide (Diabeta, Glynase PresTab, Micronase)

Increase insulin secretion in people with capacityto produce insulin; may also decrease the rate ofhepatic glucose production, and increase insulinreceptor sensitivity and the number of insulinreceptors

Sulfonylureas may need to be reduced or omittedthe day before surgery depending on the dietprescribed. They should not be used in patientswho are fasting because of the increased risk ofhypoglycemia

Meglitinides: Nateglinide (Starlix)Repaglinide (Prandin)

Increase insulin secretion by binding to K1channels on b islet cells. Repaglinide ismetabolized by the liver enzymes CYP3A4 andCYP2C8. Nateglinide is metabolized by hepaticCYP450 CYP2C9 (70%) and CYP3A4 (30%)

Meglitinides are taken immediately before eatinga meal and therefore should not be used inpatients who are fasting for surgery

Thiazolidinediones: Pioglitazone (Actos)Rosiglitizone (Avandia)

Improve target cell response to insulin; decreasehepatic gluconeogenesis. Metabolized to activemetabolites by hepatic CYP2C8 and CYP34A

Thiazolidinediones do not cause hypoglycemiaand therefore can be given when the patient isnot on nothing-by-mouth status

Biguanides:Metformin (Glucophage, Glucophage XR,

Glumetza, Fortamet, Riomet)

Decrease hepatic glucose production andgastrointestinal glucose absorption; increasetarget cell insulin sensitivity

Biguanides should not be used in female patientswith a creatinine level � 1.4 mg/dL or malepatients with a creatinine level �1.5 mg/dL.Biguanides should be withheld the day ofsurgery not restarted until good renal functionhas been verified by lab analysis and the patientis eating well

Alpha glucosidase inhibitors:Acarbose (Precose)Miglitol (Glyset)

Delay gastrointestinal absorption of carbohydrate Alpha glucosidase inhibitors are taken just beforemeals. They can be given once the patientbegins to eat meals after surgery

Dipeptidyl peptidase-4 inhibitors:Sitagliptin phosphate (Januvia)Saxagliptin (Onglyza)Linagliptin (Tradjenta)

Increase and prolong incretin hormone activity,which is inactivated by dipeptidyl peptidase-4activity; metabolism limited, primarily byCYP3A4

Dipeptidyl peptidase-4 inhibitors do not causehypoglycemia. They can be given when thepatient is not on nothing-by-mouth status

Abbreviation: CY, Cytochrome.

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Table 2Insulin

Medication NamesGeneric (Trademark) Onset Peak Duration Surgery Implication

Aspart (Novolog)Lispro (Humalog)Glulisine (Apidra)

15 min 90 min 2–4 h Used as a bolus insulin to treat hyperglycemia

Regular (Humulin R,Novolin R, Relion R)

30–60 min 2–4 h 6–8 h Used as a bolus insulin for hyperglycemia; can be given intravenously orsubcutaneously. If given subcutaneously, take care not to give toofrequently, as this can result in hypoglycemia

NPH (Humulin N, Novolin N, Relion N) 2–4 h 4–12 h 12–18 h NPH has a peak effect. Either the dose may need to be reduced or the insulindiscontinued for surgery

Detemir (Levemir)Glargine (Lantus)

4–6 h Peakless 16–24 h If the patient is fasting for a prolonged time, the basal insulin requirementwill be reduced. Many patients use basal insulin to cover foodrequirements and will need a dose reduction for surgery.

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Table 3Noninsulin injectable diabetes medications

Medication NamesGeneric (Trademark) Mechanism of Action Surgery Implication

Incretin mimetics:Exenatide (Byetta)Exenatide extended

release (Bydureon)Liraglutide (Victoza)

Synthetic analogs of exendin-4,a gila monster salivarypolypeptide that mimicsincretin and promotes insulinsecretion, suppresses glucagon,and slows gastric emptying

Incretin mimetics do not producehypoglycemia. They are givenon days when the patient isgoing to eat meals. They causedelayed gastric emptying andcan cause nausea

Amylin agonists:Pramlintide (Symlin)

Synthetic analogs of thepolypeptide pancreatichormone amylin, which slowsgastric emptying, suppressesglucagon, and regulatesappetite

Amylin agonists are givenimmediately before meals withrapid-acting insulin for themeal. They would not be givenunless the patient is eatinga meal

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INSULIN THERAPY IN SURGERY PATIENTS WITH DIABETES

Insulin replacement during the perioperative period should be administered to mimicnormal physiologic insulin release (basal/bolus), with the goal of avoiding hypogly-cemia and severe hyperglycemia. The purpose of basal insulin is to maintain adequateblood glucose control between meals. Basal insulin can include insulin detemir, insulinglargine, neutral protamine Hagedorn (NPH) insulin, or the basal rate of an insulinpump. Patients with type 2 diabetes may not require basal insulin replacement toavoid diabetic ketoacidosis; however, replacement is necessary in patients withtype 1 diabetes. The basal insulin dose may need to be decreased for surgery if thepatient reports that hypoglycemia occurs when a meal is missed or delayed, if thepatient will be missing more than one meal for surgery, or if the patient’s diet isrestricted preoperatively.Bolus insulin includes meal and correctional doses. Meal insulin is given with food to

maintain target blood glucose after eating. Correction insulin is given to bring anelevated blood glucose level down to the target range. The insulin used to maintainpostprandial insulin levels or correct hyperglycemia may be rapid-acting insulin(such as insulin aspart, insulin glulisine, and insulin lispro) or short-acting insulin(such as regular insulin).Because the patient is not eating during surgery, the rapid- or short-acting insulin is

only used for correction of hyperglycemia. On the day before surgery and again oncethe patient resumes eating meals, short- or rapid-acting insulin is given with food.Intravenous bolus doses of regular insulin are not recommended because its shortduration of action (30–40 minutes) causes wide fluctuations in the blood glucoselevel.10 For patients who are not in critical condition, the American Association of Clin-ical Endocrinologists/American Diabetes Association consensus statement recom-mends subcutaneous administration of insulin; however, very short dose intervalsshould be avoided because they can lead to hypoglycemia.9

INSULIN THERAPY IN LONG OR COMPLEX SURGICAL PROCEDURES

Intravenous insulin is preferred to subcutaneous insulin during long or complex proce-dures because tissue perfusion may be unpredictable. The half-life of intravenousregular insulin is 5–10 minutes, allowing for precise dose administration and titration

Table 4Recommendations for perioperative adjustment of diabetes medications

Medication Recommendations: Evening Before Surgery Recommendations: Day of Surgery

Sulfonylureas Withhold Withhold

Meglitinides Give with meals Withhold while patient status is nothing by mouth

Thiazolidinediones Give Withhold while patient status is nothing by mouth

Biguanides Give Withhold until the postoperative creatinine level is <1.4mg/dL in female patients and <1.5mg/dL inmale patientsand the patient resumes eating meals

Alpha glucosidase inhibitors Give with meals Withhold

Dipeptidyl peptidase-4 inhibitors Give Withhold

Incretin mimetics Give Withhold

Amylin agonists Give with meals Withhold

Rapid-Acting insulin Give usual dose for food and hyperglycemia treatment Use only for corrections of hyperglycemia

Short-Acting insulin Give usual dose for food and hyperglycemia treatment Use only for corrections of hyperglycemia

Intermediate-Acting insulin Give usual dose in the morning; may need a reduced dosethe evening before surgery

Give 50%–75% of dose before surgery

Pre-mixed insulin Give usual dose Switch to a basal/bolus method

Long-Acting insulin Give usual dose Type 1 diabetes: give 50% of usual doseType 2 diabetes: withhold or give 50% of usual dose

Insulin pump Give usual dose If discontinuing, give 50% of the total basal dose as a long-acting insulin before surgery. Check blood glucose every1–2 h and give rapid-acting insulin for correction ofhyperglycemia, being careful not to stack the insulindoses.

If patient remains on pump: have him or her seta temporary basal rate at 50%–80% of the usual rate.Make sure the pump site is intact and out of the way ofthe planned surgical site and that the pump site is lessthan 3 days old. Check blood glucose every 1–2 h andgive rapid-acting insulin for correction of hyperglycemia,being careful not to stack the insulin doses.

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based on the blood glucose level. The insulin infusion should be started early in themorning the day of surgery to allow time to achieve the target blood glucose level. Ifa patient is receiving basal insulin before surgery, the infusion should not be stoppedbefore subcutaneous basal insulin is resumed, especially if the patient has type 1diabetes.10

SLIDING-SCALE SHORT-ACTING OR RAPID-ACTING INSULIN

Sliding-scale insulin regimens, when used alone, may produce widely fluctuatingblood glucose levels because doses are given only when the patient’s blood glucoselevel is high. Patients with type 1 diabetes should never be placed on a sliding-scaleinsulin regimen alone; they must be prescribed basal insulin as well.9

DAY OF SURGERY

Surgery should be scheduled in the morning so the patient does not miss more thanone meal, which would increase the risk of catabolism. If the patient misses more thanone meal, fluid replacement may be needed to prevent gluconeogenesis, lipolysis,ketogenesis, and proteolysis and to maintain euvolemia and serum electrolyte levels.The patient’s blood glucose level should be tested at the time of his or her arrival forsurgery, every 1–2 hours during surgery, and in the immediate postoperative period.4

Again, Table 4 summarizes recommendations for adjustment of diabetes medicationson the day of surgery.Basal insulin, if needed, should be given in the morning of surgery at the usual

prescribed time. If applicable, pump use should continue until basal insulin hasbeen injected. If the patient is going to wear the insulin pump during surgery, thepump infusion site should not interfere with the surgery and be less than 3 days old.If the patient’s blood glucose level is less than 70 mg/dL, 20–50 mL of intravenous

50% dextrose (10–25 g) may be given. If there is no intravenous access, 1 mg ofglucagon may be administered via intramuscular injection. If the patient is not pro-hibited from oral intake, he or she may be given 15 g of carbohydrate by mouth inthe form of a clear liquid. The caregiver should recheck the patient’s blood glucoselevel every 15 minutes and repeat the treatment until it exceeds 70 mg/dL.

POSTOPERATIVE CARE

Most patients can resume their usual medication regimen after surgery. However,sulfonylureas and meglitinides should not be restarted until the patient is eating wellbecause of the risk of hypoglycemia. Metformin should not be restarted until goodrenal function is verified and the patient is confirmed to be neither acidotic nor havesignificant liver disease or heart failure that would predispose the patient to acidosis.Thiazolidinediones should not be restarted if congestive heart failure, significant fluidretention, or significant liver dysfunction develop.If the patient is started on tube feeding, subcutaneous insulin will probably be

needed. The insulin dose will depend on the amount of carbohydrate in the tubefeeding. If the patient is receiving total parenteral nutrition, he or she will probablyneed regular insulin as well. If the patient is on a clear liquid diet, his or her mealsmay contain little carbohydrate (if the patient chooses broth, diet Jello-O, diet soda,and similar items) or a lot of carbohydrate (if the patient chooses juices, regularsoda, regular Jello-O, and so on). The prescriber should interview the patient to ascer-tain the amount of carbohydrate that the patient will consume before ordering prandialinsulin.

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SUMMARY

There are no strong, randomized research trials supporting a single approach to peri-operative care of patients with diabetes. The literature does, however, support per-forming a thorough preoperative assessment, choosing safe glucose targets, and, ifpossible, minimizing risk factors that increase the risk of postoperative complications.When developing a hospital perioperative protocol, one should know how each classof diabetes medication works and how to adjust the dose before, during, and aftersurgery. Maintaining the blood glucose level in the target range and resuming nutritionas quickly as possible reduce the risk of acute complications such as hypoglycemia,significant hyperglycemia, diabetic ketoacidosis, hyperosmolar hyperglycemic state,electrolyte imbalances, and dehydration.

ACKNOWLEDGMENTS

The author acknowledges the Scientific Editing Department at MD AndersonHospital for reviewing and editing the manuscript.

REFERENCES

1. Centers for Disease Control and Prevention. 2011 National Diabetes Fact Sheet.Available at: http://www.dcd.gov/diabetes/pubs/estimates11htm. Accessed April12, 2012.

2. Power M, Ostrow L. Preoperative diabetes management protocol for adult outpa-tients. J Perianesth Nurs 2008;23:371–8.

3. Meneghini L. Perioperative management of diabetes: translating evidence intopractice. Cleve Clin J Med 2009;76:S53–9.

4. Dhatanya K, Levy N, Kilvert A, et al. Diabetes UK position statements and carerecommendations: NHS diabetes guideline for the perioperative managementof the adult patient with diabetes. Diabet Med 2012;29:420–33.

5. DiNardo M, Donihi A, Forte P, et al. Standardized glycemic management andperioperative glycemic outcomes in patients with diabetes mellitus who undergosame-day surgery. Endocr Pract 2011;17:404–11.

6. Dronge A, Perkal M, Kancir S, et al. Long-term glycemic control and postopera-tive infectious complications. Arch Surg 2006;141(4):375.

7. Van den Berghe G, Wouters P, Weekers F, et al. Intensive insulin therapy in thecritically ill patients. N Engl J Med 2001;345:1359–67.

8. NICE-SUGAR Study Investigators. Intensive vs conventional glucose control incritically ill patients. N Engl J Med 2009;360:1283–97.

9. Moghissi E, Korytkowsi M, DiNardo M, et al. American Association of ClinicalEndocrinologists and American diabetes Association consensus statement oninpatient glycemic control. Diabetes Care 2009;32:1119–31.

10. Joshi G, Chung F, Vann M, et al. Society for Ambulatory Anesthesia consensusstatement on perioperative blood glucose management in diabetic patientsundergoing ambulatory surgery. In: International Anesthesia Research Society.2010. Available at: http://anesthesia-analgesia.org/content/early/2010/10/01/ANE.0b013e3181f9c288.full.pdf. Accessed April 12, 2012.