麻醉專科醫師 覃事台

Key Concepts Improper face mask technique, continued deflation of reservoir bag when APL valve closed, substantial leak around the mask. High breathing circuit pressures with minimal chest movement and breath sounds, obstructed airway or tubing. LMA, partially protects the larynx from pharyngeal secretions, but not gastric regurgitation . After insertion of a tracheal tube (TT), cuff inflated with least amount of air necessary to seal, minimize the pressure transmitted to the tracheal mucosa .

Detection of CO2 by a capnograph, best confirmation of tracheal placement of a TT, cannot exclude bronchial intubation. The earliest evidence of bronchial intubation, increase in peak inspiratory pressure. Esophageal intubation produce catastrophic results. direct visualization of TT tip passing through the vocal cords, careful auscultation of bilateral breath sounds, absence of gastric gurgling through the TT, analysis of exhaled CO2 (the most reliable method), CXR, or fiberoptic bronchoscopy.

Clues to the diagnosis of bronchial intubation: unilateral breath sounds, unexpected hypoxia with pulse oximetry, inability to palpate the TT cuff in the sternal notch during cuff inflation, decreased breathing bag compliance (high peak inspiratory pressures). The large negative intrathoracic pressures generated by a struggling patient in laryngospasm, development of negative-pressure pulmonary edema even in healthy patients.