Which clinical sign may indicate a patient is under-ventilated?

Increased heart rate can be a clinical sign indicating that a patient is under-ventilated. When a patient is not getting enough ventilation, it can lead to an accumulation of carbon dioxide (hypercapnia) and a decrease in oxygen levels (hypoxia). The body's response to this physiological stress typically includes an increase in heart rate as a compensatory mechanism to improve oxygen delivery to tissues and organs. This increased heart rate signifies the body’s effort to maintain homeostasis in the face of inadequate ventilation and is commonly observed in patients experiencing respiratory distress or inadequate alveolar gas exchange.

Other clinical signs commonly associated with under-ventilation may include altered mental status, increased respiratory rate, and pursed-lip breathing, but an increased heart rate is one of the more readily observable physical signs in acute settings. While decreased heart rate, stable mental status, and hypothermia may be relevant clinical parameters, they do not typically indicate under-ventilation in the same way that an increased heart rate does.