When disease processes impair clearance of pulmonary secretions, airway clearance techniques may help maintain airway patency. One method is chest percussion, which moves secretions toward the central airways, from which they can be expectorated. Chest physiotherapy can also be performed effectively with handheld devices that generate expiratory back-pressure and vibration (TheraPEP, Flutter, and Acapella) and pneumatic vests. Chest physiotherapy is most beneficial in children with chronic airway secretions, especially those with CF. Children who are too weak to generate an effective cough benefit from the use of a mechanical cough assist device, used in conjunction with chest physiotherapy. Chest physiotherapy is not generally beneficial for patients with asthma or pneumonia, and its effectiveness in patients with atelectasis has not been clearly established.
If the upper airway is obstructed or mechanical ventilation is needed, it may be necessary to provide the patient with an artificial airway. This is best done by placing an endotracheal tube via the mouth or nose into the trachea (intubation).Intubation alters the physiology of the respiratory tract in many ways, not all of which are beneficial. It interferes with the humidification, warming, and filtration of inspired air and prevents phonation. Intubation also stimulates secretion production. However, in acute/impending respiratory failure, intubation with an endotracheal tube is lifesaving.
Endotracheal tubes can damage the larynx and the airways if the tubes are of improper size and are not carefully maintained. The cricoid ring is the narrowest segment of a child’s airway and is completely surrounded by cartilage, which makes it vulnerable to damage, and may lead to subglottic stenosis. If the pressure created by the tube against the airway mucosa exceeds capillary filling pressure (roughly 35 cm H2O), mucosal ischemia develops, leading to necrosis. Therefore, a small air leak should be maintained around the endotracheal tube to minimize the risk of mucosal damage.
Artificial airways must be kept clear of secretions asobstruction with mucous plugs can be fatal. Providing adequate humidification of inspired air and appropriate suctioning of the tube reduce the probability of occlusion by secretions. In addition to endotracheal tubes, the laryngeal mask airway (LMA) can be used to provide mechanical ventilation. This device consists of a tube with a soft mask at the distal end that is placed over the larynx, creating a seal without the trachea being instrumented. Although less invasive,the LMA is less secure, so it is generally limited to proceduralanesthesia.
Tracheostomy is the surgical placement of an artificial airway into the trachea below the larynx. If prolonged intubation is anticipated, elective tracheostomy may be used to prevent laryngeal trauma, obviate the danger of accidental extubation, increase patient comfort, and facilitate nursing care. No clear guidelines are available as to how long patients can be intubated without sustaining airway damage or when a tracheostomy is indicated.
Children with severe chronic upper airway obstruction or those requiring long-term mechanical ventilation may benefit from tracheostomies. Because the tracheostomy tube hampers the ability to phonate and communicate, the child must be monitored carefully at all times. As with endotracheal tubes, tracheostomy tubes must be kept clear of secretions. Occlusion of the tube or accidental dislodgment of the tube can be fatal. Many children with tracheostomy tubes can be cared for at home provided the caregivers are well trained and adequately equipped.
Patients who are unable to maintain adequate gas exchange may require mechanical ventilation. Most modes of mechanical ventilation involve inflation of the lungs with gas using positive pressure. The inspiratory phase is active (air is pushed in) and exhalation is passive.