A nurse is preparing a 65-year-old client with type 2 diabetes mellitus for a total knee arthroplasty at 8:00 AM. During the 6:00 AM preoperative assessment, the client's blood glucose level is 190 mg/dL. Which priority action should the nurse implement?

Priority action for diabetic surgical clients with elevated preoperative glucose levels

When caring for a diabetic patient scheduled for surgery, maintaining optimal blood glucose control is crucial to prevent perioperative complications. A blood glucose level of 190 mg/dL is elevated but within the acceptable range (generally 80-200 mg/dL) that allows surgery to proceed. The nurse's priority action is to administer the prescribed sliding scale insulin to bring the preoperative blood glucose level closer to the target range.

Perioperative hyperglycemia in diabetic patients increases the risk of several complications, including delayed wound healing, increased infection rates, impaired immune function, and prolonged hospital stays. The stress response to surgery naturally raises blood glucose levels through the release of counter-regulatory hormones such as cortisol, epinephrine, and growth hormone. Therefore, aggressive blood glucose management is essential.

Sliding scale insulin protocols are specifically designed to address elevated blood glucose levels in hospitalized patients, especially during the perioperative period. The insulin dose is calculated based on the current blood glucose level, allowing for individualized treatment. Administering the prescribed insulin helps optimize the patient's metabolic state before the surgical procedure.

Timing is critical, as the surgery is scheduled for 8 AM and administering insulin at 6 AM allows sufficient time for blood glucose stabilization. This proactive approach demonstrates appropriate clinical judgment and adherence to evidence-based perioperative diabetes management protocols.

Understanding the Clinical Context

This client is in the immediate preoperative period, with surgery scheduled in two hours. The blood glucose of 190 mg/dL is elevated above the recommended target range for surgical patients. In the context of total joint arthroplasty, this finding requires a specific and timely intervention, not just passive documentation.

Why Blood Glucose Control Matters in Arthroplasty

The connection between hyperglycemia and surgical complications is well-established. Diabetes mellitus accompanies approximately 30% of hip and knee arthroplasty cases and more than doubles the risk of periprosthetic joint infection (PJI), wound failure, and other adverse outcomes ^[1]. The physiological mechanism involves impaired leukocyte function, including reduced chemotaxis and phagocytosis, in a hyperglycemic environment, which directly compromises the immune system's ability to defend the surgical site. Therefore, a glucose level of 190 mg/dL on the morning of surgery is not merely a number to document; it represents a modifiable risk factor for a devastating complication.

Evaluating the Priority Action

The question asks for the priority action, which requires applying clinical judgment based on the available evidence and standard protocols.

- Option 1: Administer prescribed sliding scale insulin as ordered. This is the correct action. Sliding scale insulin is a standard preoperative order for patients with diabetes precisely for this situation. It allows the nurse to independently correct an elevated glucose level within prescribed parameters to bring it into a safer range before the surgical incision is made. Early postoperative hyperglycemia is a critical concern, and aggressive management begins in the preoperative period ^[2]. Administering the insulin now addresses the problem directly and promptly, optimizing the client's condition for surgery.

- Option 2: Notify the surgeon immediately about the elevated glucose level. While the surgeon needs to be aware of the client's overall status, a glucose of 190 mg/dL in a known patient with diabetes is an expected finding that should be managed by the nurse using existing standing orders. Immediate notification is not the priority when a prescribed intervention (sliding scale insulin) is available to correct the issue. This action would delay necessary treatment.

- Option 3: Encourage the client to drink additional fluids. This is contraindicated. The client is NPO (nothing by mouth) for a surgery scheduled at 8:00 AM. Encouraging oral intake would violate preoperative fasting guidelines and increase the risk of aspiration during anesthesia.

- Option 4: Document the findings and continue with preoperative preparation. This is an unsafe and passive action. Documenting an abnormal value without intervening ignores the significant risk of surgical site infection and other complications associated with perioperative hyperglycemia ^[1]. The nurse must act to correct the abnormality.

Integrating Evidence into Practice

The rationale for immediate correction is strongly supported by current literature. The American Diabetes Association’s Standards of Care emphasizes the importance of glycemic control in the hospital setting to improve clinical outcomes . Furthermore, research using continuous glucose monitoring (CGM) in arthroplasty patients has identified that early postoperative hyperglycemia is a significant concern, making preoperative optimization a logical and critical step ^[2]. The goal is to achieve normoglycemia, and using a prescribed insulin sliding scale is the standard, nurse-driven method to manage this in the immediate preoperative phase. While CGM with real-time alerts is an emerging technology to help achieve this goal, the fundamental principle of proactive correction with insulin remains the cornerstone of care . The nurse acts as the first line of defense by recognizing the elevated value and implementing the prescribed corrective treatment without delay.