Ventilator Modes and Settings

Assist-control mode delivers a full preset tidal volume for every breath, whether triggered by the client or the ventilator, ensuring full ventilatory support, but can cause hyperventilation if the client breathes rapidly. Synchronized intermittent mandatory ventilation delivers a set number of breaths synchronized with the client's effort while allowing spontaneous breaths in between, often used during weaning. Pressure support ventilation assists spontaneous breaths with a set pressure, requiring the client to initiate every breath, making it appropriate for clients strong enough to do more of their own work. FiO2 and PEEP settings are adjusted based on oxygenation goals, while tidal volume and respiratory rate are adjusted based on ventilation (CO2) goals.

Alarm Troubleshooting

High-pressure alarms indicate increased resistance to airflow, commonly from secretions requiring suctioning, biting the tube, kinked tubing, coughing, or bronchospasm; assess and address the cause rather than silencing the alarm without action. Low-pressure alarms indicate a leak or disconnection, such as a loose connection, cuff leak, or accidental extubation, requiring immediate assessment of the airway and connections. The NCLEX tests a critical safety principle: if a ventilator malfunction can't be quickly identified and resolved, disconnect the client from the ventilator and manually ventilate with a bag-valve-mask while a colleague troubleshoots the equipment, never leaving the client without ventilation while investigating the alarm cause.

Weaning Criteria and VAP Prevention

Readiness to wean is indicated by stable vital signs, adequate oxygenation with minimal PEEP and FiO2 requirements, ability to initiate spontaneous breaths, adequate cough and gag reflex, and resolution of the underlying condition that necessitated ventilation. A spontaneous breathing trial assesses tolerance before extubation. VAP prevention, tested through the VAP bundle, includes elevating the head of bed to 30-45 degrees, daily sedation vacations to assess readiness for extubation, oral care with chlorhexidine, DVT and stress ulcer prophylaxis, and maintaining appropriate cuff pressure to prevent aspiration around the tube while avoiding tracheal damage from excessive pressure.