TY - CHAP M1 - Book, Section TI - Airway Management A1 - Butterworth IV, John F. A1 - Mackey, David C. A1 - Wasnick, John D. Y1 - 2022 N1 - T2 - Morgan & Mikhail’s Clinical Anesthesiology, 7e AB - KEY CONCEPTS Improper face mask technique can result in continued deflation of the anesthesia reservoir bag despite the adjustable pressure-limiting valve being closed, usually indicating a substantial leak around the mask. In contrast, the generation of high breathing circuit pressures with minimal chest movement and breath sounds implies an obstructed airway or obstructed tubing. The laryngeal mask airway partially protects the larynx from pharyngeal secretions but not gastric regurgitation. After insertion of an endotracheal tube (ETT), the cuff is inflated with the least amount of air necessary to create a seal during positive-pressure ventilation to minimize the pressure transmitted to the tracheal mucosa. Although the persistent detection of carbon dioxide (CO2) by a capnograph is the best confirmation of tracheal placement of an ETT, it cannot exclude bronchial intubation. The earliest evidence of bronchial intubation often is an increase in peak inspiratory pressure. After intubation, the cuff of an ETT should not be felt above the level of the cricoid cartilage because a prolonged intralaryngeal location may result in postoperative hoarseness and increases the risk of accidental extubation. Unrecognized esophageal intubation can produce catastrophic results. Prevention of this complication depends on direct visualization of the tip of the ETT passing through the vocal cords, careful auscultation for the presence of bilateral breath sounds and the absence of gastric gurgling while ventilating through the ETT, analysis of exhaled gas for the presence of CO2 (the most reliable automated method), chest radiography, airway ultrasonography, or use of fiberoptic bronchoscopy. Clues to the diagnosis of bronchial intubation include unilateral breath sounds, unexpected hypoxia with pulse oximetry (unreliable with high inspired oxygen concentrations), inability to palpate the ETT cuff in the sternal notch during cuff inflation, and decreased breathing bag compliance (high peak inspiratory pressures). The large negative intrathoracic pressures generated by a struggling patient in laryngospasm can result in the development of negative-pressure pulmonary edema, particularly in healthy patients. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=1190605256 ER -