When the ventilator alarm sounds, the nurse finds the ICU patient lying in bed holding the endotracheal tube (ET). Which action would the nurse take first?

Choice D rationale

The change in the endotracheal tube position from 21-cm to 24-cm strongly suggests that the tube has migrated downward, likely entering the right mainstem bronchus. This results in the ventilation of only one lung, which explains the patient's anxiety and restlessness due to declining oxygenation. The first priority is to auscultate the lungs to check for bilateral breath sounds. Normal breath sounds are usually 12 to 20 breaths per minute, and oxygen saturation should be above 94 percent.

Choice A rationale

Notifying the healthcare provider is necessary when a change in the patient's condition or equipment occurs, but it is not the immediate first action. The nurse must first perform a rapid assessment to gather objective data regarding the patient's respiratory status and the impact of the tube displacement. Having information about the presence or absence of bilateral breath sounds and current oxygen saturation levels allows the nurse to provide a more effective and urgent report to the provider.

Choice B rationale

Bagging the patient with 100 percent oxygen is an intervention used for severe distress or suspected tube dislodgement. However, if the tube has simply moved into a mainstem bronchus, bagging through the displaced tube may not provide effective ventilation to both lungs and could potentially cause barotrauma to the ventilated side. The nurse must first assess the lung sounds to confirm the tube's position and the patient's actual ventilatory status before opting for manual bag-valve-mask ventilation.

Choice C rationale

While providing emotional support is important, the patient's anxiety is likely a physiological response to hypoxia caused by the tube's migration into the bronchus. Restlessness is a classic early sign of inadequate oxygenation. Focusing on psychological reassurance before addressing the potential airway compromise is unsafe. The nurse must prioritize physical assessment and corrective actions to ensure the airway is patent and both lungs are being ventilated to resolve the underlying cause of the patient's distress.

Choice A rationale

While PEEP can eventually lead to improved lung compliance, its primary and immediate mechanical purpose is not the reduction of the work of breathing. In fact, excessively high levels of PEEP can sometimes increase the work of breathing by causing overdistention of the alveoli, making it harder for the patient to initiate a breath or move air effectively. Its therapeutic focus remains on gas exchange rather than the muscular effort of ventilation.

Choice B rationale

This choice is scientifically incorrect because PEEP is specifically designed to increase the functional residual capacity, which is the volume of air remaining in the lungs at the end of a normal expiration. By maintaining positive pressure, PEEP prevents the total collapse of the lungs during the expiratory phase. Decreasing this capacity would lead to widespread atelectasis and a significant decline in the surface area available for gas exchange at the alveolar-capillary membrane.

Choice C rationale

Tidal volume is the amount of air moved in or out of the lungs during a single respiratory cycle and is typically determined by the ventilator settings or the patient's effort. While PEEP improves the environment for air delivery, it is not used as a primary mechanism to increase the specific volume of a single breath. Instead, it maintains a baseline pressure that keeps the respiratory architecture open for the duration of the cycle.

Choice D rationale

The fundamental purpose of PEEP is to improve oxygenation by keeping alveoli open at the end of expiration, a process known as recruitment. This prevents atelectasis and increases the surface area for gas exchange. By maintaining open alveoli, it reduces intrapulmonary shunting, where blood flows past unventilated lung tissue. This mechanism allows for a lower fraction of inspired oxygen to be used while maintaining adequate arterial oxygen tension and systemic delivery.