Which breathing pattern is NOT associated with a lesion in the brain stem?

Kussmaul breathing is characterized by deep, labored breaths often associated with metabolic acidosis, particularly diabetic ketoacidosis. This breathing pattern is a compensatory mechanism initiated by the body in response to a high level of acidity in the blood and is primarily a physiological response rather than a direct result of brain stem lesions.

In contrast, apneustic breathing, Cheyne-Stokes breathing, and hyperpnea are all associated with specific neurologic conditions or lesions affecting the brain stem. Apneustic breathing is characterized by a prolonged inspiratory phase and is typically indicative of damage to the pons. Cheyne-Stokes respiration involves a cyclic pattern of apnea followed by gradually increasing and then decreasing tidal volumes, often seen in patients with severe brain injury or heart failure, indicating potential brain stem involvement. Hyperpnea refers to an increase in the depth and rate of breathing and can occur due to various factors, including central nervous system pathology.

Thus, Kussmaul breathing stands out as a pattern that does not reflect underlying brain stem lesions, making it the correct answer in this context.