Table 4.3—Medications
| Increasing hyperglycemia risk | Increasing hypoglycemia risk |
| Corticosteroids | β-blockers |
| β-agonists | Incretins (when used with insulin, sulfonylureas) |
| Protease inhibitors | Sulfonylureas |
| Sirolimus | Haloperidol |
| L-asparagine | Pentamidine |
| Atypical antipsychotics | Tramadol |
The nutritional needs of the patient need to be coordinated with a coherent plan for insulin therapy, and the prescription for insulin therapy must reflect the current nutritional therapy and route, as well as provide for a change in insulin therapy if nutritional intake is reduced or stopped. Different methods of nutrition require different types of insulin, and sometimes different routes. For example, basal insulin dosing twice daily may be optimal for enteral feedings, but IV insulin is best when oral intake is uncertain and the expected insulin requirements may decrease rapidly. Orders for varying contingencies, such as what to do if oral intake is suddenly interrupted, will reduce errors.
Poor communication between the prescribing and treating health-care providers can result in an error of inadequate insulin dosage. For example, if a pulmonary intensivist adds β-agonists and corticosteroids for the respiratory needs of the patient, but the prescriber of insulin is unaware that the consultant, in effect, has increased the insulin resistance, the prescriber will choose inadequate insulin doses that will result in severe hyperglycemia.
The route of insulin administration is a key consideration. A patient with shock and hypotension or severe dehydration may be highly likely to have delayed and erratic absorption from subcutaneous (SQ) sites. An IV approach for insulin therapy would be much more effective. Alternately, in another scenario, the rapidity of the change in insulin resistance may be so fast that only an IV use of insulin therapy will be able to match the rapidity of the change in insulin needs.
The type of medical record, either paper-based or electronic, may affect the type and frequency of prescription errors. In paper-based hospital records, the errors may occur when prescribers write down what they believe to be the correct insulin type, but instead list an incorrect type of insulin because the insulin they chose had a similar sounding, but incorrect, type (short-acting versus long, or vice-versa). This kind of error is often termed an intentional error. In contrast, an example of a so-called unintentional error is a misspelling or error in the prescriber’s penmanship, which makes the result ambiguous in appearance. The most common error is using a “U” to depict units, which, if not written clearly, may be read as a zero. Another common error is to have a trailing zero after a decimal point, as for example, an IV insulin rate of 1.0 units/h, which, if the decimal point is not easily visible, may be seen as 10 units/h. Other examples of prescribing errors occur when the orders are verbal and may not be clearly understood by the transcriber, who is not familiar with the plan. These common errors can be reduced with the use of evidence-based order sets, preferably in an EHR.
Transcribing Errors
Transcription errors, while much more common when paper charts are used or a verbal order is transcribed, also may occur whenever there is a transition of care and a new set of orders is used. In many hospitals, a reconciliation of medication is done on a transfer from one care unit to another, and a new set of orders for insulin is generated. The person who performs the reconciliation is the one who may cause a transcription error and it is particularly common upon discharge in cases in which new orders are generated for post-hospital care. As an example, in one recent study, 18% of all patients who were discharged after an acute myocardial infarction (MI) did not receive their medications to control blood glucose levels upon discharge.36 Sixty-seven percent of the time, one of the omitted medications was insulin.36 Their retrospective review confirmed that 81% of the time, the omission of the medication for glycemic control upon discharge was the result of medical error. The frequency of readmission postdischarge is directly related to such errors upon discharge. The “hand-offs” in care transitions are among the events at highest risk for errors.
Dispensing Errors
Dispensing insulin can be a complex process and can vary widely from one institution to another. The trend, correctly so, is to have the hospital pharmacy solely responsible for the labeling, storage, and dispensing of the insulin to the nurse who is to administer the dose, whether it be IV or SQ. The pharmacist usually has the responsibility of being sure that the correct insulin dose is in the IV solution that is to be administered, and in the single dose pen or syringe that is to be sent to the floor, but the accuracy of the dispensing process is not guaranteed. As with all aspects of the processes of care, it is helpful to keep metrics on the performance in the pharmacy regarding errors of all types and to provide timely feedback so workflows can be changed to improve performance.
Storage Errors
Storage of insulin is an issue in the hospital setting and can be the source of serious errors. There are many types of these errors. Some hospitals, for example, may use U-500 insulin as well as the standard concentration, U-100 insulin, and may store the U-500 insulin vials in the clinical area, at the nurses’ station, for the convenience of the staff. This error type can be remedied by storing U-500 insulin in the hospital pharmacy and dispensing it only with bar-code labeling that is specific for a patient on the clinical unit. Some insulin pens and vials, however, may be stored on the unit in a secure drawer, for the individual patient. The use of double-checks and bar coding of all insulin-containing pens or vials or syringes is highly recommended to reduce risk of patient injury.
Administering Errors
After prescribing and transcribing errors, the administration of insulin is perhaps the next most frequent type of error, and it is certainly the one that is most visible. Unfortunately, in many hospitals, the important function of administering the dose of insulin is not done without frequent errors. A recent review of insulin therapy error data from the British National Patient Safety Agency showed the high frequency in which patients received a wrong dose, strength, or frequency of insulin.2 They also found that insulin doses were commonly omitted or the wrong insulin product was used.
Prefilled insulin IV containers and insulin syringes prepared by the pharmacy may reduce the burden somewhat, but there are many potential sources of error. The nurse needs to double-check to ensure that the ordered insulin dosage is correct. In addition to checking the insulin type, route, and dose, time may have elapsed since the order was given, and understanding whether the order for this dose of insulin is still appropriate for the patient is important. Communication between nurses and physicians is essential to the safety of insulin administration. In many discussions on errors of insulin therapy, the role of the nurse in catching errors or potential errors made by others is overlooked, but in one study, 86% of the errors that were avoided were found by the nurses.37
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