Which of the following is a sign of adequate ventilation?

Adequate ventilation is indicated by various physiological signs, among which equal chest rise and fall is a key indicator. When a patient exhibits equal chest rise and fall during ventilation, it suggests that air is being effectively distributed throughout both lungs. This symmetrical movement indicates that both sides of the thoracic cavity are receiving air, allowing for optimal gas exchange in the alveoli.

Conversely, the use of accessory muscles during breathing is typically a sign of respiratory distress and increased effort to breathe, indicating that ventilation may not be adequate. Rapid, shallow breathing can also signal a problem with ventilation, often seen in conditions like anxiety or respiratory distress, where the tidal volume may be compromised. Additionally, blue discoloration of the lips, known as cyanosis, is a concerning sign indicating inadequate oxygenation, which often accompanies poor ventilation. Thus, the observation of equal rise and fall of the chest is a clear and reliable sign that ventilation is occurring effectively.