Strategies for Continuous Intravenous Insulin Infusion Therapy
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Continuous intravenous insulin (CII) infusion is often used to treat severely decompensated diabetes, eg, in the diabetic ketoacidosis or hyperosmolar nonketotic state or in the perioperative or periprocedural setting. IV insulin infusion therapy confers several theoretical advantages when compared with subcutaneous insulin injection because of its rapid time to onset and offset of insulin action.5 When administered judiciously, it allows smooth and timely reduction in BG levels to facilitate achieving target levels. IV insulin also allows dosing flexibility that can accommodate fluctuating clinical status, illness, stress-related changes in insulin sensitivity, whether the patient is eating or is on a nothing-by-mouth (NPO) regimen, has had previously ill-defined insulin requirements, or will be undergoing surgery or a procedure.
Rapid resolution of hypoglycemia when the insulin infusion rate is lowered or the drip is discontinued generally allows avoidance of severe hypoglycemia. Among the 765 patients receiving intensive insulin therapy and 783 receiving conventional treatment in the Van den Berghe study, only 39 patients (5%) and 6 patients (<1%), respectively, experienced hypoglycemia defined as BG level of 40 mg/dL or less. None of these patients had severe adverse clinical outcomes associated with these episodes of hypoglycemia during insulin infusion therapy.
Table 3 illustrates the insulin adjustment algorithm from the Portland Protocol, which is one of the published insulin infusion protocols that provide a basis for the most commonly used intensive care unit insulin infusion adjustment algorithms.21
Table 3. Insulin Titration
Blood Glucose |
Action |
<75 mg/dL |
Stop insulin. Give 25 cc dextrose 50% water (D50w) and recheck BG every 30 minutes. When BG reaches >150 mg/dL, restart at 50% of previous rate. |
75 mg/dL to 100 mg/dL |
Stop insulin. Recheck BG every 30 minutes. When levels reach >150 mg/dL, restart at 50% of previous rate unless the dose is less than 0.25 U/hr. |
101 mg/dL to 125 mg/dL |
If <10% lower than last BG, decrease rate by 0.5 U/hr. If >10% lower than last BG, decrease rate by 50%. If neither occurs, continue current rate. |
126 mg/dL to 175 mg/dL |
Same rate |
176 mg/dL to 225 mg/dL |
If lower than last BG, continue the same rate.
If higher than last BG, increase rate by 0.5 U/hr. |
>225 mg/dL |
If >10% lower than last BG, continue same rate.
If <10% lower than last BG or if higher than last BG, increase rate by 1 U/hr. |
Source: The Portland Protocol for Continuous Intravenous Insulin Infusion in Post Operative Cardiac Surgery Patients.22
