What are nursing concerns associated with IV administration of insulin?
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often complicates the clinical course of critically ill patients in the intensive care unit (ICU). Intravenous insulin infusions can control hyperglycemia more efficiently than intermittent subcutaneous insulin therapy and may be the preferred approach in certain settings, such as postcardiac surgery. Many intravenous insulin protocols have been developed, such as the Georgia Hospital Association Protocol and the Portland Protocol. [1] Show
Indications for intravenous insulinBecause of their susceptibility to deep wound infections, patients who undergo open cardiac surgery may benefit from the routine use of intravenous insulin. Patients with diabetes who have suboptimal glucose control with conventional subcutaneous insulin treatment may also benefit from intravenous therapy. Target blood glucose levelsThe optimal range of glucose control in critically ill patients remains to be determined. A blood glucose level between 140 and 180 mg/dL is recommended for most of these patients. Certain subgroups, such as those undergoing cardiothoracic surgery, may benefit from a lower target range (ie, 110-140 mg/dL). Reduction of glucose levels to below 110 mg/dL is no longer recommended because of the risk of hypoglycemic complications. Intravenous insulin protocolsAmong the differences between the various intravenous insulin protocols are the following:
Despite these differences, most protocols agree that hypoglycemia is associated with worse outcomes. Important considerations in the development of a protocol include allowing 6-8 hours to safely lower blood glucose to target levels, reducing the risk of hypoglycemia, and accounting for patient insulin sensitivity and resistance. The need for bedside calculation of insulin doses increases the risk of dosing errors. Preprinted dosing charts and computerized protocols that eliminate the need for calculation may minimize this problem. Although the success of an insulin protocol depends on many different variables, nursing input and acceptance are crucial.  Next: OverviewPatients with hyperglycemia in the ICU have increased morbidity and mortality. Hyperglycemia is associated with immune dysfunction, increased systemic inflammation, and vascular insufficiency. Elevated blood glucose levels have been shown to worsen outcomes in medical patients who are in the ICU for more than 3 days. Hyperglycemia may result from stress, infection, corticosteroid therapy, decreased physical activity, discontinuation of outpatient regimens, and nutrition. [2] Improved control of hyperglycemia improves patient outcomes, but clinical confirmation of this thesis has proved elusive. Significant interest was generated by initial single-center results that have not been replicated in multisite studies. A randomized controlled study by van den Berghe et al in a surgical ICU demonstrated a decrease in mortality from 8% to 4.6% in patients with intensive continuous intravenous insulin therapy. [3] The authors repeated the protocol in a study of 1200 patients in a medical ICU. [4] The conventional treatment group was treated to maintain a blood glucose level between 180 and 200 mg/dL, whereas the intensive treatment group was treated to maintain a blood glucose level between 80 and 110 mg/dL. Mortality was not significantly reduced by intensive insulin therapy and was actually higher in patients in the intensive treatment group who were in the ICU for less than 3 days. In patients who were in the ICU for longer than 3 days, the intensive treatment group did demonstrate reduced morbidity from decreased kidney injury, earlier weaning from mechanical ventilation, and earlier discharge from the medical ICU and hospital. occurred more often in the intensive treatment group than in the conventional treatment group. In addition, an experienced physician was actively involved in administration of the protocol, a luxury not uniformly available to many hospitals and a variable that limited the ability to generalize their results to other centers. However, the results were encouraging and represented a marked improvement in several areas, stimulating great interest in tight glucose control with intravenous insulin, which, in turn, stimulated the development of a multitude of intravenous insulin protocols. However, the protocols widely varied, and little uniformity was observed among medical centers. Questions persisted as to the optimal protocol and targets and the need for a unified, uniform approach to control of hyperglycemia. The Normoglycemia in Intensive Care Evaluation–Survival Using Glucose Algorithm Regulation (NICE-SUGAR) study by Finfer et al was a large, international, randomized trial intended to address the shortcomings of previous studies. [5] The study enrolled 6104 patients who were assigned to either tight glucose control with a target of 81-108 mg/dL or conventional glucose control with a target of 180 mg/dL or less. At the end of the 90-day study period, mortality was 27.5% of patients in the tight glucose control group and 24.9% of patients in the conventional control group, with an odds ratio of 1.14 for death with tight glucose control. No significant difference in the median length of stay in the ICU or hospital was noted. Severe hypoglycemia was significantly more common with tight glucose control. This experience dampened the routine use of intravenous insulin in the management of critically ill patients; however, continuous intravenous insulin therapy still has a role in this setting. Previous Next: Key Components of Insulin ProtocolsIntravenous insulin titration protocols have been in place for several years and predate the experience outlined by van den Berghe et al but were not widely considered or adopted until after the report. [3] Since the NICE-SUGAR report, the pendulum has shifted away from near universal intravenous insulin therapy for the critically ill to utilization in selected patients. It remains an important component of patient management, especially in patient subgroups, such as those undergoing open cardiac surgery. Several tenets of a successful, effective intravenous insulin protocol have been recognized; the protocol used is only a minor component. Implementation of an insulin protocol without key nursing, physician, and administrative support is doomed to fail. Key components to the institution of an intravenous insulin protocol are as follows:
Previous Next: IndicationsAs noted above, patients with hyperglycemia are at risk for adverse outcomes, and infections are a common clinical indicator of the risk associated with hyperglycemia. Patients undergoing cardiac surgery seem to be especially susceptible to deep wound infections, specifically sternal wound infections. This is probably the one group of patients who may still benefit from the routine use of intravenous insulin for glucose control. Experience from several institutions and data that incorporate both observational and randomized investigations indicate improvement in mortality and rate of sternal wound infections with the use of intravenous insulin. [3, 6] The evidence to support the use of intravenous insulin in this patient subgroup has been designated as a class I recommendation by the Society of Thoracic Surgeons. [7] Routine use of continuous insulin protocols is not endorsed for any other subgroup, but general experience does support its use in those diabetic patients in whom control of hyperglycemia has been demonstrated to be difficult with conventional subcutaneous treatment. In some circumstances, diabetic patients who require therapy that interferes with optimal glucose control, such as corticosteroid therapy, may also be candidates for intravenous insulin. These recommendations for the use of intravenous insulin differ markedly from previous practice and reflect the results of the multicenter NICE-SUGAR trial. Intravenous insulin can no longer be recommended as a routine treatment in the ICU but should be reserved for patients who undergo open cardiac surgery and patients with diabetes who have suboptimal glucose control as a result of their underlying diabetes, infection, or therapy. Previous Next: Optimal Range of Glucose ControlThe results of the experience with intravenous insulin and tight glucose control led to a re-examination of the optimal range of glucose control. Although control of hyperglycemia did reduce infection rates, especially after cardiothoracic surgery, a net benefit was tempered by higher rates of hypoglycemia and mortality. The ideal target blood glucose level in the intensive care setting has yet to be established but seems to be less than 180 mg/dL (< 10 mmol/L). The lowest acceptable threshold for serum glucose has not been established. However, given the increased risk of hypoglycemia associated with insulin protocols that sought to control blood glucose levels between 80 and 110 mg/dL, a goal of less than 110 mg/dL cannot be endorsed. This was also the sentiment of a consensus statement that suggested a glucose target of 140-180 mg/dL in critically ill patients; however, certain subgroups, such as patients undergoing cardiothoracic surgery, may benefit from a lower target range. [1, 8] Therefore, a glucose target of 110-140 mg/dL may eventually be a more appropriate range for this subgroup and other critically ill patients; however, this level of control has not been subjected to rigorous investigation and determined with evidence-based support. The Society of Thoracic Surgeons examined the evidence for intravenous insulin; although they endorsed the use of intravenous insulin therapy in patients undergoing cardiac surgery, they did not endorse a strict glucose target range. They cited evidence that supports a target glucose of less than 180 mg/dL using intravenous insulin for at least the first 24 hours postoperatively, with a target of less than 150 mg/dL if the ICU stay exceeds 3 days because of comorbidities requiring mechanical ventilation, inotropes, ventricular-assist devices, intra-aortic balloon pumps, antiarrhythmics, or renal replacement therapy. [7] In summary, the optimal range of glucose control in critically ill patients remains to be determined. A glucose control target between 140 and 180 mg/dL is recommended in most critically ill patients. Those with a higher severity of disease may benefit from control that aims for the upper threshold to be less than 150 mg/dL. The burden of experience and the risk of hypoglycemic complications no longer support efforts to further reduce glucose levels below 110 mg/dL. Previous Next: Pitfalls in Bedside Glucose MeasurementAccurate serum glucose levels are crucial to the successful implementation of any intravenous insulin protocol. Timely and accurate glucose measurements guide the dosing of insulin and affect decisions about implementation, adjustment, and discontinuation. Hypoglycemia is the most feared adverse effect of intravenous insulin therapy, not only for its impact on neurologic function but also because of the association of hypoglycemia with increased mortality. Moreover, the warning signs of hypoglycemia are often difficult to appreciate in the critically ill patient. The need for rapid testing in critically ill patients has spawned multiple bedside, point-of-care devices, and none is more pervasive in the ICU than the bedside glucometer. [9] Accuracy is reduced, with standards requiring only an agreement of ±20% with laboratory analysis. The glucometers are most accurate in hemodynamically stable patients with glucose readings in the normal range, but disagreements with laboratory readings are more pronounced with glucose readings at the high and low ends of the spectrum (hyperglycemia and hypoglycemia) and in conditions of poor tissue perfusion (eg, in critically ill patients who are subject to shock, peripheral edema, and vasoconstriction). In addition, the point-of-care devices tend to overestimate finger-stick glucose measurements, and the difference in glucose levels between capillary blood and venous blood can be as high as 70 mg/dL. Adjusting insulin infusions based on inaccurate glucose measurements may lead to errors in the insulin dose on both ends of the spectrum, as well as a failure to detect hypoglycemia. [10, 11] Factors that affect point-of-care blood glucose measurements include the following [10] :
Previous Next: Intravenous Insulin Protocol SelectionMultiple intensive insulin protocols have been developed to manage hyperglycemia; however, no singular protocol has been universally accepted. Significant similarities in strategy exist among the various protocols, and the differences relate to bolus amounts, infusion rates, and target glucose goals. [12] The complexity of these differences can be better appreciated in the summary of variations of protocols outlined below. Areas of variation in insulin protocols are as follows:
Logistics of implementation are as follows:
Despite these differences, most protocols agree that hypoglycemia is associated with worse outcomes. The danger of both hyperglycemia and hypoglycemia is related to the level and duration of the glucose abnormality. An ideal protocol would aim to reduce such glucose variability. Important considerations in the development of a protocol include allowing 6-8 hours to safely lower glucose to target, reducing the risk of hypoglycemia, and accounting for patient insulin sensitivity and resistance. The American College of Endocrinology and the American Diabetes Association have released a consensus statement on inpatient glycemic control. [1, 8] They reiterated the impact of tight glycemic control on improved clinical outcomes. Although implementation of new protocols at institutions would create an increase in cost upfront, such an investment would reap long-term financial benefits by potentially reducing morbidity and patients’ length of stay. Quality and safety issues were addressed in light of the dangers of hypoglycemia; common errors include a lack of coordination between feeding and the administration of medications, insufficient blood glucose monitoring, unclear and unstandardized orders, and a failure to recognize changes in the underlying medical conditions that may alter changes in insulin requirements. Insulin protocols are expected to increase the incidence of hypoglycemia; however, the harm of hypoglycemia can be minimized if mild, transient, and rapidly diagnosed. The success of an insulin protocol depends on many different variables. Various protocols have been developed and modified by different institutions, with the choice often based on elements that are especially suited to the institution. A specific protocol cannot be endorsed, as the implementation and the success of the protocol will depend on several factors, including patient population, ease of use, expertise and experience of staff, infrastructure, and medical resources. Each protocol has a learning curve, especially if staff members are not accustomed to the use of intravenous insulin infusions for glucose control. The protocols are labor intensive and require extra nursing time for implementation. Hourly glucose determinations are required initially; if only 5 minutes are devoted to each check, 12 adjustments to the infusion in a day translates into an extra hour of nursing time. Although experience with insulin infusions used to treat will help the transition to these intravenous insulin protocols, the need for close oversight cannot be overestimated. It is acknowledged that the need for bedside calculation of insulin dose adds to the potential for errors in dosing, especially when paper based protocols are used. Preprinted dosing charts and computerized protocols that eliminate the need for calculation are available and may minimize this problem. Two archetypal approaches are presented in more detail: the Georgia Hospital Association Protocol [13] , also referred to as the Davidson or Glucommander Protocol, and the Portland Protocol. [14] The Georgia Hospital Association Research and Education Foundation developed their own guidelines in 2002 for inpatient diabetes care throughout the state’s hospitals; this standardized approach to manage hyperglycemia has also been referred to as the Davidson or Glucommander Protocol, and authors of this protocol are also involved in the construct of the latest protocol. Although calculations are involved in determining insulin dose, the protocol has also been published in a columnar dosing form to eliminate the need for these calculations. The Providence Heart and Vascular Institute developed the Portland Protocol from data extrapolated from diabetic patients who underwent cardiac surgery. It has undergone multiple modifications since its inception and takes into account many of the nuances previously identified. Both protocols are available from the respective websites and have been modified with glucose targets that are less stringent than the previous 80-110 mg/dL and closer to the 140-180 mg/dL range. These changes should also reduce the incidence of hypoglycemia that was associated with earlier protocols. Previous Next: Georgia Hospital Association Intravenous Insulin ProtocolThe Georgia Hospital Association Intravenous Insulin Protocol has also been referred to as the Davidson or Glucommander Protocol. The intravenous infusion protocol is for a target of 140-180 mg/dL. Initial orders are as follows:
Intravenous insulin administration is as follows:
Initiate the intravenous insulin flow sheet. Blood glucose testing is as follows:
Determination of intravenous infusion rate is as follows: units of insulin per hour = (blood glucose – 60) × 0.02. [15]
Treatment for hypoglycemia is as follows:
Notify a physician if the following is observed:
Transition to subcutaneous insulin is as follows:
Previous Next: The Portland ProtocolThe Portland Protocol, which targets a blood glucose level of 125-175 mg/dL, is summarized below. The protocol is initiated on all ICU patients as follows (place these orders on all ICU admission and postoperative order sets):
Mix 1 unit of regular human insulin per 1 mL of 0.9% normal saline and start intravenous infusion via pump as follows:
General orders are as follows:
Protocol duration is as follows:
Transition to floor (ward) from the ICU is as follows:
Protocol cessation permissible only on transfer is indicated in the following:
Test blood glucose by finger stick, arterial, or venous line drop samples. Frequency of testing is as follows:
The Portland Protocol Titration Guidelines are listed below. Insulin infusion may be titrated between 0 and 30 U/hr using these guidelines to rapidly (within 3 h) achieve and maintain blood glucose in the target range (125-175 mg/dL). Round insulin infusion to the nearest tenth of a unit (0.1 U) when necessary. If the blood glucose level is less than 40 mg/dL or more than 450 mg/dL, obtain a confirmatory laboratory blood glucose level.
The Portland Meal Orders and Adjunctive Periprandial Subcutaneous Dosing Schedules are listed below. The ICU target blood glucose level is 125-175 mg/dL. The 1800 American Diabetes Association Diabetic Diet starts with any oral intake. When the diet is advanced, begin with full liquids or sugar-free clear liquids and advance as tolerated. Patient may take oral or enteral nutrition at any time in conjunction with this protocol. Prandial subcutaneous rapid-acting insulin analogue (Humalog/Novolog/Apidra) is administered in addition to insulin infusion at meal times. For the patient’s first meal, administer subcutaneous rapid-acting insulin analogue immediately after the meal, according to the dosing schedule in the table below. Table 1. Subcutaneous Rapid-acting Insulin Analogue Dosing. (Open Table in a new window) Insulin Infusion Drip Rate at First Meal Eats >50% of Meal Eats 25-50% of Meal Snacks or Eats < 25% of Meal Row 0-1.9 U/hr 4 U 2 U 1 U 1 2-3.9 U/hr 6 U 3 U 2 U 2 4-5.9 U/hr 8 U 4 U 3 U 3 6-7.9 U/hr 10 U 5 U 4 U 4 8-10 U/hr 12 U 6 U 5 U 5 More than 10 U/hr 14 U 7 U 6 U
Chart the row number used from the above dosing schedule from the initial meal. Continue protocol blood glucose level frequency monitoring and treatment as noted in the intravenous portion of this protocol. For all subsequent meals and periprandial subcutaneous rapid-acting insulin analogue doses and titration, use the table below. Note: Ignore the insulin intravenous insulin infusion rate after the first periprandial dose calculation and adjust all further doses using the row number references. If the patient is consistently eating the entire meal tray, administer subcutaneous rapid-acting insulin analogue when the tray arrives at bedside. If oral intake is uncertain, administer subcutaneous rapid-acting insulin analogue immediately after the meal. Based on a postprandial blood glucose level reading obtained approximately 2 hours after subcutaneous rapid-acting insulin analogue was given, and using the initial row number as the first baseline row, titrate (adjust) the subcutaneous dosing schedule row number for the next meal as follows:
Table 2. Subsequent Meals and Periprandial Subcutaneous Rapid-Acting Insulin Analogue Doses and Titration. What are the nursing considerations when administering insulin?Nursing Implementation with Rationale
Gently rotate the vial containing the agent and avoid vigorous shaking to ensure uniform suspension of insulin. Rotate injection sites to avoid damage to muscles and to prevent subcutaneous atrophy. Monitor response carefully to avoid adverse effects.
What is the major complication of IV insulin therapy?Hypoglycemia is the most common and most serious complication of insulin therapy. Hypoglycemia can be potentially life-threatening. Most patients who use insulin experience hypoglycemia at one time or another. If a patient injects too much insulin blood glucose level can fall low enough to cause hypoglycemia.
What should I monitor with insulin drip?The American Diabetes Association and the Society of Critical Care Medicine recommend monitoring blood glucose (BG) every 1-2 hours in patients receiving insulin infusion to guide titration of insulin infusion to maintain serum glucose in the target range; however, this is based on weak evidence.
What is the most common error of insulin administration?In terms of the forms of insulin administration error, the most common error types were the wrong dose, omitted or delayed insulin. The current common known contributing factors leading to insulin error were transcribing errors, drug calculation mistakes, non-adherence to protocols, and failure in communication.
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