A patient is connected to the ventilator. His eyes are closed and he appears calm. The ventilator is making soft rhythmic noises, and the patient’s chest is expanding and receding in unison with the ventilator. A sweep of signals is gently traversing the monitor screen.
This peaceful scene erupts suddenly. The patient bolts upright. His eyelids retract. His nostrils flare. Sweat drips from his brow. His skin turns blue. His sternocleidomastoids contract vigorously. His rib spaces retract. One or more alarms sound loudly.
A patient fighting (or bucking) the ventilator is frightening not only to the patient but to staff. If the physician cannot find the source of the problem and fix it, the patient may die in minutes. The physician must immediately diagnose and manage the problem, and do both concurrently. The physician quickly scans the monitors for clues. Sometimes the problem is immediately spotted and solved, such as disconnected ventilator tubing.
If the cause is not immediately obvious, the physician’s primary responsibility is to ensure adequate ventilation. This requirement takes precedence over diagnosis. After disconnecting the patient from the ventilator, the physician (or staff) starts to ventilate the patient manually with a self-inflating bag containing 100% oxygen. This step is both therapeutic and diagnostic (Fig. 53-1).1,2 If the distress resolves, it indicates that the problem originated in the ventilator. If the distress continues, it indicates the problem is within the patient.
Removing the patient from the ventilator and providing manual ventilation with a bag (100% oxygen) is both therapeutic and diagnostic. Patient improvement indicates that the ventilator is the cause of the distress. Lack of improvement indicates that the problem is within the patient. If death appears imminent, the physician rapidly checks for airway obstruction (by passing a suction catheter), a dislodged endotracheal or tracheostomy tube, and a pneumothorax (if deemed likely, a small-gauge needle is inserted); depending on the clinical picture, other life-threading problems, such as aortic dissection, should be considered. If death is not imminent, the physician undertakes a more detailed physical examination and assessment of monitored variables. A chest radiograph may also be obtained. Paw, airway pressure; VT, tidal volume.
Where a physician begins the assessment varies with the particulars of the patient’s presentation. The following sequence is not appropriate for all patients.
Because hypoxia can be rapidly lethal, the pulse oximeter reading is noted. Although several factors can give rise to erroneous readings, the displayed saturation generally bears a close relationship to the oxygen saturation on an arterial blood-gas test.3
If the high-airway-pressure alarm is sounding, the physician should, if possible, perform an end-inspiratory occlusion maneuver to measure the plateau pressure (Fig. 53-2). An increase in peak airway pressure without a proportional increase in plateau pressure indicates narrowing ...