A nurse is assisting a client with ambulation several hours after a hip replacement. Which of the following postoperative complications is the nurse trying to prevent?

A. Venous thromboembolism: Early ambulation promotes venous return and prevents stasis of blood in the lower extremities, which is a primary risk factor for deep vein thrombosis. Mechanical movement of the calf muscles acts as a pump for the venous system. Preventing thrombus formation reduces the subsequent risk of life-threatening pulmonary embolism. This is a critical postoperative nursing priority. B. Postoperative malnutrition: Malnutrition results from inadequate protein and caloric intake required for tissue repair and metabolic demands during recovery. While activity can stimulate appetite, ambulation is not a direct intervention used to manage nutritional status. Nutritional support involves oral intake, enteral, or parenteral therapy rather than physical mobility. Ambulation specifically targets circulatory and respiratory complications. C. Postoperative delirium: Delirium is an acute cognitive decline often triggered by anesthesia, electrolyte imbalances, or sensory deprivation in the hospital environment. While mobilization can help orient a client, it is not the primary physiological prevention strategy for neurocognitive disturbances. Managing sleep cycles and metabolic stability are more specific interventions for delirium. Ambulation primarily addresses the risk of vascular clots. D. Malignant hyperthermia: Malignant hyperthermia is a rare, life-threatening pharmacogenetic reaction to volatile anesthetic gases or succinylcholine. It occurs during or immediately after the administration of anesthesia and involves a rapid rise in body temperature and muscle rigidity. Ambulation has no preventative effect on this biochemical muscular reaction. Management requires the administration of dantrolene and rapid cooling measures.