A nurse is conducting a preoperative assessment on a 22-year-old client with type 1 diabetes mellitus scheduled for an orthopedic surgery this morning. Which assessment finding is the most critical priority for the nurse to report to the surgeon immediately?

The presence of ketones in urine combined with significantly elevated blood glucose indicates diabetic ketoacidosis (DKA), a life-threatening condition that requires immediate intervention and would contraindicate elective surgery.

This question tests critical thinking about a nurse's ability to prioritize diabetes complications and life-threatening situations during the perioperative period. The detection of ketones in urine and a blood glucose of 350 mg/dL indicate diabetic ketoacidosis (DKA), a medical emergency that absolutely contraindicates elective surgery.

DKA occurs when there is a lack of insulin to allow glucose into cells, causing the body to break down fat for energy. This process produces acidic compounds called ketones, which can lead to severe metabolic acidosis. The combination of hyperglycemia (>250 mg/dL), ketonuria, and metabolic acidosis defines DKA. Symptoms include nausea, vomiting, abdominal pain, fruity-smelling breath, rapid and deep breathing (Kussmaul breathing), and altered consciousness.

Surgery places additional stress on the body, increasing cortisol and other stress hormones that further elevate blood glucose levels. Performing surgery on a patient in DKA is extremely dangerous and can lead to serious complications including cardiovascular collapse, cerebral edema, and death. Surgery should be postponed until DKA is resolved through aggressive fluid resuscitation, insulin therapy, and electrolyte correction.

The other options, while concerning, are not immediate life-threatening emergencies that contraindicate surgery. A blood glucose of 180 mg/dL is elevated but manageable, an HbA1c of 8.5% indicates long-term poor control but does not affect immediate surgical safety, and mild hypertension can be managed during the perioperative period.

Understanding the Priority: Why Ketones with Hyperglycemia is a Preoperative Emergency

In the preoperative setting, the nurse's most critical responsibility is to identify and report findings that indicate an immediate threat to life or could lead to catastrophic surgical complications. For a client with type 1 diabetes mellitus, the absolute priority is recognizing and preventing diabetic ketoacidosis (DKA), a life-threatening metabolic emergency. The presence of ketones in the urine with a blood glucose of 350 mg/dL (19.4 mmol/L) is a classic and severe presentation of DKA. This finding must be reported immediately, as proceeding with surgery in a state of active DKA carries an extremely high risk of mortality from severe dehydration, electrolyte imbalances (particularly life-threatening hyperkalemia followed by hypokalemia during treatment), cardiac arrhythmias, and cerebral edema.

Clinical Reasoning and Pathophysiology

To understand why this is the priority, it is essential to connect the pathophysiology of DKA to the stress of surgery. In type 1 diabetes, an absolute insulin deficiency prevents glucose from entering cells. The body, perceiving a state of starvation, initiates a cascade of counter-regulatory hormone release (glucagon, cortisol, catecholamines) that promotes hepatic gluconeogenesis and glycogenolysis, worsening the hyperglycemia. Simultaneously, the lack of insulin and excess counter-regulatory hormones activate lipolysis in adipose tissue, releasing free fatty acids. These are oxidized in the liver to ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone), leading to a high anion gap metabolic acidosis. Surgery itself is a profound physiological stressor that amplifies the release of these same counter-regulatory hormones, which would dangerously accelerate the DKA process in an already ketotic patient ^[1].

Analyzing the Other Options

A blood glucose of 180 mg/dL without ketones indicates hyperglycemia but not a ketotic crisis. While it requires correction per protocol, it does not represent the same immediate, life-threatening emergency as active DKA. A hemoglobin A1C of 8.5% signifies poor long-term glycemic control, which increases risks for poor wound healing and infection postoperatively. This is a significant concern that must be documented and communicated, but it is a chronic management issue, not an acute crisis requiring immediate surgical cancellation. A blood pressure of 150/90 mmHg with a heart rate of 88 bpm could be related to pain, anxiety, or undiagnosed hypertension. While it warrants investigation and stabilization, it does not carry the same imminent risk of mortality as a profound metabolic derangement like DKA.

A Critical Note on Euglycemic DKA

A vital clinical pearl from recent literature is the concept of euglycemic DKA, a condition where ketoacidosis occurs with near-normal blood glucose levels, often below 250 mg/dL. This is increasingly recognized in patients using SGLT2 inhibitors but can also occur in type 1 diabetes during states of major stress, such as surgery, with reduced caloric intake or pregnancy. It presents with non-specific symptoms like nausea, vomiting, and generalized lassitude, making it prone to underdiagnosis ^[1]. This highlights a crucial nursing insight: the absence of severe hyperglycemia does not rule out DKA. The nurse must always correlate the patient's clinical presentation with laboratory findings, particularly ketones and serum bicarbonate or anion gap, rather than relying on blood glucose level alone. In this scenario, the classic presentation of hyperglycemia and ketonuria leaves no room for doubt, but it serves as a reminder that ketone assessment is the non-negotiable component of the preoperative evaluation for a patient with type 1 diabetes.