A nurse is caring for a 22-year-old male client with anorexia nervosa who has been admitted to the psychiatric unit. The client's vital signs show: temperature 97.0°F (36.1°C), heart rate 48 bpm, blood pressure 90/55 mmHg, and respirations 14/min. The client appears cachectic with a BMI of 15.8 kg/m², reports fatigue and cold intolerance, and has laboratory results revealing hypomagnesemia and hypophosphatemia. The client also reports feeling dizzy when standing, with additional laboratory results showing hypokalemia and hyponatremia. Which nursing intervention should be the priority?

Continuous cardiac monitoring is priority due to severe bradycardia (48 bpm), hypotension, and multiple electrolyte imbalances (hypomagnesemia, hypophosphatemia, hypokalemia, hyponatremia) that pose a high risk for life-threatening arrhythmias in this anorexia patient. Other options address psychological or nutritional aspects but are secondary to immediate medical stabilization.

Clinical Priority Analysis

This client presents with a constellation of findings that signal a high-risk metabolic emergency. The diagnosis of anorexia nervosa with a BMI of 15.8 kg/m² indicates severe malnutrition. The vital signs—bradycardia (48 bpm), hypotension (90/55 mmHg), and hypothermia (97.0°F / 36.1°C)—reflect a hypometabolic state, a compensatory mechanism to conserve energy during starvation. The client’s report of dizziness upon standing suggests orthostatic hypotension, a consequence of volume depletion and compromised cardiovascular function.

The most critical finding is the combination of electrolyte disturbances: hypomagnesemia, hypophosphatemia, hypokalemia, and hyponatremia. In the context of severe malnutrition, this pattern is a hallmark of impending or early refeeding syndrome (RFS), even before nutritional supplementation has begun. According to the systematic review and meta-analysis by Fremont et al., electrolyte abnormalities in individuals with eating disorders are strongly associated with adverse clinical outcomes ^[2]. The pathophysiology of RFS, as detailed by Senthil et al., involves a sudden shift from fat and protein catabolism to carbohydrate metabolism upon refeeding, causing a surge in insulin release. This insulin drives phosphate, potassium, and magnesium into cells, precipitously dropping their serum levels ^[1].

These intracellular shifts critically destabilize cardiac function. Severe hypophosphatemia depletes adenosine triphosphate (ATP) stores, impairing myocardial contractility. Hypokalemia and hypomagnesemia disrupt cardiac electrical conduction, prolonging the QT interval and predisposing the patient to life-threatening ventricular arrhythmias, including torsades de pointes and sudden cardiac arrest ^[1]. The client’s pre-existing bradycardia and hypotension indicate a heart with limited physiological reserve, making it exquisitely vulnerable to these electrolyte fluctuations. Fluid overload, another component of RFS, can further precipitate heart failure in a weakened myocardium ^[1].

While establishing a therapeutic relationship, providing nutritional education, and encouraging group therapy are all essential components of comprehensive eating disorder treatment, they are not the immediate priority. The client’s physiological instability and high risk for a fatal cardiac event demand urgent medical stabilization. The inpatient nutritional rehabilitation protocol described by Peebles et al. emphasizes the importance of a structured approach to prevent RFS, which begins with meticulous medical monitoring . Continuous cardiac monitoring allows for real-time detection of arrhythmias, enabling prompt intervention. This intervention directly addresses the pathophysiological mechanism of the greatest threat—a lethal cardiac arrhythmia secondary to electrolyte derangement—and aligns with the preventive strategies necessary to manage RFS risk ^[1].