Mechanical ventilation is a life-supporting medical intervention used to assist or replace spontaneous breathing when a patient's respiratory system fails. A mechanical ventilator delivers a mixture of oxygen and air under positive pressure into the patient's lungs through an artificial airway, such as an endotracheal tube or a tracheostomy tube. This process ensures adequate gas exchange by facilitating oxygen intake and carbon dioxide elimination. It does not cure the underlying disease process; instead, it buys critical time for medical therapies to treat the root cause of respiratory failure.
Patients require mechanical ventilation when their respiratory system fails to maintain basic life-sustaining gas exchange or when the work of breathing becomes unsustainable. Common clinical indicators include acute respiratory failure, severe hypoxemia, progressive hypercapnia, airway protection deficits due to altered neurological status, and extreme physical exhaustion.
Modern mechanical ventilators consist of a main control unit, a gas source supplying oxygen and compressed air, a humidification system, and a circuit of tubing connecting to the patient. Ventilator modes dictate how the machine interacts with the patient's own breathing efforts.
| Mode | Description |
|---|---|
| CMV / Assist-Control | The ventilator delivers a preset volume or pressure for every breath, whether initiated by the machine or the patient. |
| SIMV | The machine delivers mandatory breaths at a set rate but allows the patient to breathe spontaneously between them without full machine support. |
| CPAP | Provides continuous positive pressure to keep airways open during spontaneous breathing without delivering mechanical breaths. |
Continuous monitoring of a mechanically ventilated patient is essential to detect acute complications and evaluate therapy effectiveness. Nurses must frequently assess vital signs, oxygen saturation via pulse oximetry, end-tidal carbon dioxide levels, and ventilator pressures. Physical assessment involves checking chest symmetry, auscultating breath sounds bilaterally to confirm proper endotracheal tube placement, and monitoring for signs of respiratory distress or agitation.
Managing a ventilated patient requires comprehensive daily nursing interventions. Oral care using chlorhexidine gluconate must be performed regularly to reduce bacterial colonization in the oral cavity. The patient's head of the bed should be elevated between 30 and 45 degrees unless medically contraindicated. Nurses must manage sedation levels, ensure secure tube placement with tape or specialized holders, and perform sterile endotracheal suctioning only when clinically indicated by secretions or coarse breath sounds, rather than on a rigid routine schedule.
Ventilator-associated pneumonia, barotrauma, and oxygen toxicity are serious risks associated with mechanical ventilation. Ventilator-associated pneumonia develops when bacteria enter the lower respiratory tract, often mitigated by strict hand hygiene, subglottic secretion drainage, and daily awakening trials to assess readiness for breathing independently. Barotrauma occurs when high airway pressures rupture alveoli, leading to conditions like pneumothorax. Nurses remain vigilant by monitoring peak inspiratory pressures and watching for sudden chest asymmetry or respiratory distress.
Weaning is the gradual process of transitioning a patient from mechanical ventilator support back to spontaneous breathing. The medical team evaluates readiness through spontaneous breathing trials, assessing parameters like respiratory rate, tidal volume, and oxygenation status. Once the patient demonstrates the ability to breathe independently and maintain a patent airway with effective cough reflexes, the artificial airway is removed in a procedure known as extubation. Post-extubation care focuses on monitoring for stridor, hoarseness, and respiratory distress.