Hyperglycemia and Switching to Subcutaneous Insulin
A 47-year-old man with type 2 diabetes was admitted to the hospital with nonketotic hyperglycemia due to medication nonadherence. He was placed on a transitional care (step-down) unit and the decision was made to start an intravenous (IV) insulin drip to control his hyperglycemia. This hospital used the Glucommander—a computer-based system that recommends insulin and IV fluid infusion rates based on the patient's blood glucose levels—for protocol-based management of hyperglycemia. The admitting physician entered initial orders into the Glucommander, and the system recommended changes to the infusions based on subsequent blood glucose measurements. Within several hours, the patient's blood sugars improved from over 600 to less than 200, so, per the protocol, his insulin infusion was decreased and the IV fluids were changed to D5 1/2 NS (hypotonic saline with added dextrose).
That evening, the patient began to experience chest pain. An electrocardiogram (ECG) was performed and showed T-wave inversions in the lateral leads, prompting concern for cardiac ischemia. The cross-covering resident and attending saw the patient and decided to transfer him to the intensive care unit (ICU) for closer monitoring. The patient was made NPO (nothing by mouth) in case an urgent cardiac procedure was required. The resident therefore decided to discontinue the Glucommander, as he did not want the patient to experience dangerously low blood sugars. Orders were written for the patient to receive sliding scale subcutaneous insulin, and his IV fluids were changed to normal saline with no added dextrose.
The patient's chest pain quickly resolved and he had no further ECG changes or evidence of cardiac ischemia. However, over the next several hours, the patient developed hyperglycemia, with blood sugars over 400. When the primary physician saw the patient the next morning, she realized that although normal protocol called for starting subcutaneous insulin 2 hours prior to discontinuing IV insulin, the patient actually did not receive any subcutaneous insulin until more than 2 hours after the infusion was stopped. As a result, the patient's blood sugars rapidly rose. This required him to remain in the ICU for an additional day in order to adequately manage his hyperglycemia, and led to a longer hospital stay. On review of the incident, the resident admitted that he had never actually transitioned a patient off the Glucommander to subcutaneous insulin, and the ICU nurse also had limited experience with this technology.
by Tosha Wetterneck, MD, MS
This case highlights issues with inpatient glycemic control and the management of hyperglycemia. Inpatient glycemic control has received global attention, as better control is associated with improved patient outcomes, including decreased mortality and less health care utilization.(1) In addition, the case also has broader lessons about the management of increasingly ubiquitous technologies in the management of many different disease states.
Diabetes care guidelines discuss the transition from intravenous (IV) to subcutaneous insulin in patients with type 2 diabetes admitted with hyperglycemia.(2,3) Blood sugars should be in the target range of 140–180 and stable for at least 4 hours on the insulin infusion before transition. A basal and bolus subcutaneous insulin regimen of long- and short-acting insulins, determined from insulin needs over the previous 12–24 hours, is recommended. Basal insulin is started before discontinuing the insulin infusion to allow the former to reach therapeutic levels.
Based on these guidelines, this patient was inappropriately transitioned. Stable insulin dosing had not been achieved, enteral feeding was stopped, and overlap of IV and subcutaneous insulin did not occur. Not surprisingly, the patient's blood sugars quickly went out of control. Maintaining the continuous insulin and dextrose infusions in this situation would have been a better approach, allowing for closer monitoring and titration of insulin dosing even while the patient was NPO.
The systems approach is recommended for adverse event analysis and systems (re)design.(4) The Systems Engineering Initiative for Patient Safety (SEIPS) model of work systems and patient safety (5) describes five interacting elements of the work system: people, tasks, tools and technology, organization, and environment. The Table outlines contributing factors for this event based on the work system elements.
The major systems focus of this event is the people–technology interaction. Glucommander technology is designed to be programmed for standardized blood sugar management for patients on both IV and subcutaneous insulin to improve glucose control.(6) The nurse enters the blood sugar into Glucommander and computer algorithms calculate the insulin rate and timing of the next blood sugar. Glucommander also has a specific module to assist with transition from IV to subcutaneous insulin. In this case, the physician did not use the Glucommander for the insulin transition, and the ICU nurse had limited experience with its use.
From a systems perspective, tools and technologies, like protocols, are mechanisms to help workers complete tasks. Importantly, the design and usability of tools and technologies—including how they are implemented by an organization and how they fit into the workflow—will affect their use.(7) Major organization-wide patient care protocols (like inpatient glycemic control) require clinician education and practice. The organization is responsible for training and assessing clinician competencies for technology and protocol use. However, the physician and the nurse in this case clearly lacked knowledge of the institution's glycemic protocols and technology. Lack of familiarity with new technology is an increasingly important patient safety problem.
As they have previously in other industries, technology implementation and automation are increasingly occurring in health care to improve quality and safety. In aviation, the Federal Aviation Administration reported two major concerns with increasing levels of automation: (i) overreliance on automation and (ii) inadequate training of workers on technology use as it becomes more sophisticated.(8,9) Thus, automation designed to improve safety may itself be a major safety threat, a concern displayed in a recent sentinel event alert on safe health information technology use and related errors.(10) Overreliance on technology can lead to clinician reluctance to take over for automated systems when technology protocols are not achieving good outcomes. Skill degradation may also occur as technology takes over tasks once completed by clinicians. Yet the use of technology like Glucommander to implement and automate glycemic control has positive impacts throughout the system, improving glycemic outcomes (6) while decreasing calculation errors and saving nursing time.(11) As glycemic control becomes more automated, physicians and nurses need ongoing opportunities to improve their knowledge and skills in diabetes management. Organizations must have ongoing competency assessment and technology training to support optimal performance.
Other tools that organizations can use to prevent these errors include teamwork training and efforts to improve the culture of safety. The positive influence of physician–nurse teamwork with diabetes management should not be underestimated. Nurses can drive the organizational use of glycemic control protocols through their role in administering these protocols at the bedside. An organizational culture of safety promotes teamwork and standard practice using the Glucommander and glycemic control protocols. With the establishment of performance measurement for inpatient glycemic control (3,12), organizations are now under increased pressure to continually assess glycemic control and monitor the processes that support good outcomes, including those related to culture and teamwork.
Additional systems factors likely contributed to the problems in this case (Table). A cross-covering resident who responded to an unrelated acute chest pain event ordered the insulin and IV change. This raises the question of what information was covered in the change of shift handoff regarding glucose management and contingency planning for any unplanned interruption in nutrition. Moreover, the attending physician's oversight of the new care plan is unclear. The patient also changed nursing units at the time of the management change; the ICU nurse was also newly managing this patient and may not have understood the overall plan for glucose management. Task factors, such as time pressure and issues associated with acute coronary syndrome management and the workload of cross-covering residents, may also have contributed.
Safety is a systems property.(5,7,13) Therefore, the safety of glucose management depends on safe system design. System redesign to improve glycemic management should address all systems elements, as well as interactions between the elements.(14) Designing for users means both physical performance (e.g., programming a technology) and cognitive performance (e.g., correctly managing glycemic control during unplanned interruptions in enteral intake).(13) The Table summarizes the systems redesign recommendations that an organization should implement to address this type of error. The ultimate goal of system design is to support clinicians taking care of patients in a high quality, safe manner while maintaining the ability of clinicians to have a satisfying working life.(13)
- Guidelines exist to support the safe transition from intravenous to subcutaneous insulin in hospitalized patients.
- Technology is increasingly being used to support high quality reliable care delivery. Overreliance on technology and inadequate training of clinicians on technology are safety threats that must be actively dealt with by organizations.
- Safety is a systems property. Multiple contributing factors usually exist when adverse events occur and safety will only be realized when a systems approach to improvement is utilized.
Tosha Wetterneck, MD, MS Medical Director of Patient Safety, UW Health, Madison, WI Associate Professor of Medicine, University of Wisconsin School of Medicine and Public Health Researcher, Center for Quality and Productivity Improvement & Systems Engineering Initiative for Patient Safety, University of Madison, Wisconsin
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Table. Work System Factors Underlying Adverse Event and Potential Solutions.
|Work System Factor||Contributing Factor to Adverse Event||Systems Redesign Recommendations|
|Tools and Technology||
|Environment (Internal and External)||
ICU = intensive care unit; IV = intravenous