Mechanical ventilation is a life-saving intervention used when a patient cannot maintain adequate gas exchange independently. The primary goals are to support or manipulate gas exchange, increase lung volume, and reduce the work of breathing. Common indications in Nigerian clinical practice include severe acute respiratory distress syndrome, status asthmaticus unresponsive to medical therapy, acute exacerbations of chronic obstructive pulmonary disease, severe head injury requiring airway protection, and exhaustion of the respiratory muscles during sepsis or severe malaria.
Normal spontaneous breathing relies on negative pressure ventilation. The diaphragm contracts, dropping intrapleural pressure below atmospheric pressure, which draws air into the lungs. In contrast, mechanical ventilators deliver positive pressure, pushing air into the lungs against natural resistance. This positive pressure alters hemodynamics by increasing intrathoracic pressure, which can reduce venous return to the heart and lower cardiac output, a crucial factor to monitor in hypovolemic patients.
Ventilator modes define how the machine interacts with the patient's respiratory drive. Selection depends on the patient's level of consciousness, respiratory effort, and underlying pathology.
When a patient is newly intubated, the nurse and physician must verify initial ventilator settings to ensure safe gas exchange without causing volutrauma or barotrauma. Standard parameters include tidal volume, respiratory rate, fraction of inspired oxygen, and positive end-expiratory pressure. Tidal volume is typically calculated based on the patient's predicted body weight rather than actual weight to prevent overdistension of healthy lung tissue. Positive end-expiratory pressure keeps alveoli open at the end of expiration, improving oxygenation and preventing alveolar collapse.
Continuous surveillance of a mechanically ventilated patient prevents fatal complications such as accidental extubation or tension pneumothorax. Nurses must perform regular physical assessments, checking chest symmetry, breath sounds, and endotracheal tube depth markings at the lips or teeth. Pulse oximetry and end-tidal carbon dioxide monitoring provide real-time feedback on oxygenation and ventilation status. Ventilator high and low-pressure alarms must never be silenced or ignored, as they indicate critical changes in patient compliance or circuit integrity.
Caring for a ventilated patient demands rigorous, multi-system nursing interventions. Oral care using chlorhexidine solutions prevents ventilator-associated pneumonia by reducing bacterial colonization in the oropharynx. The head of the bed should be elevated between 30 and 45 degrees to minimize aspiration risk. Airway hygiene requires sterile suctioning techniques, performed only when clinically indicated by secretions or coughing, rather than on a rigid schedule. Nurses also manage sedation and analgesia to keep patients comfortable while avoiding prolonged paralysis.
Mechanical ventilation carries significant risks that require prompt identification and troubleshooting. Ventilator-associated pneumonia, barotrauma leading to pneumothorax, oxygen toxicity, and stress ulcers are common hazards. When a high-pressure alarm sounds, the nurse must quickly evaluate for common causes such as patient coughing, biting the endotracheal tube, bronchospasm, mucus plugging, or a kinked ventilator circuit. If the cause is not immediately found or the patient deteriorates, disconnect the patient from the ventilator and manually ventilate with a bag-valve-mask device while calling for emergency assistance.
Weaning is the gradual process of transitioning a patient from mechanical ventilatory support back to spontaneous breathing. Candidates for weaning must show hemodynamic stability, adequate oxygenation, reversal of the underlying disease process, and an intact cough reflex. A spontaneous breathing trial using a T-piece or low levels of pressure support is frequently used to assess readiness. Once the patient passes the trial, the nurse prepares equipment for extubation, explains the procedure, suctions the airway thoroughly, deflates the cuff, and removes the tube at peak inspiration.