Basic Airway Management Principles
The immediate availabilty of alternative and evaluated backup devices for the management of difficult face-mask ventilation (MV) and conventional tracheal intubation should be provided for all anesthetizing locations, a prerequisite for safe patient care universally claimed by expert working groups (2, 10, 11, 22, 32, 43). This is best accomplished by the provision of a dedicated and well-equipped difficult airway (DA) cart in a designated location.
Expert working groups emphasize that preoxygenation by breathing oxygen through a face mask with airtight seal should be performed in all patients, particularly in those with reduced oxygen reserves and functional residual capacity, to delay arterial desaturation during apnea and airway interventions. Traditional preoxygenation with normal tidal volume breathing for two to three minutes may be more effective than fast-track preoxygenation with four deep breaths (5, 40).
Maintenance of oxygenation, particularly between tracheal intubation attempts, should be given the highest priority (2, 22, 32, 43). There are various techniques for the application of supplemental oxygen to the patient throughout the process of airway management (AM); opportunities for supplemental oxygen administration include oxygen delivery by nasopharyngeal airways, face masks, and laryngeal mask airways (LMAs).
Traditional rapid-sequence induction (RSI) of general anesthesia (GA) for patients at high risk of pulmonary aspiration includes preoxygenation, application of predetermined drug doses for induction and muscle relaxation, cricoid pressure (CP), and apnea until tracheal intubation (24). Particularly in patients with low tolerance for apnea, this procedure may lead to rapid arterial desaturation. The controlled RSI technique with titrated induction of GA, usually with propofol and supplemented when necessary, use of a non-depolarizing neuromuscular blocking drug with rapid onset such as rocuronium, and gentle, pressure-controlled MV with oxygen until complete muscle relaxation may maintain oxygenation and provide optimum conditions for tracheal intubation without pressure for time (38).
The effectiveness of CP for the prevention of gastric fluid regurgitation and pulmonary aspiration during induction of GA and tracheal intubation has never been demonstrated in a randomized controlled study. There is evidence, that CP may increase the risk of impeded or failed MV, LMA insertion, and conventional laryngoscopy and tracheal intubation (12). In these situations, CP should be partially or completely released to establish ventilation and allow tracheal intubation (12, 38); some experts believe that CP should be generally abandoned because of lacking scientific evidence of benefits and possible complications.
Recommendations of the Austrian Working Group for Airway Management
We highly recommend the immediate availability of alternative and evaluated backup devices for difficult MV and conventional tracheal intubation for all anesthetizing locations, best accomplished by a well-equipped DA cart. We further emphasize routine preoxygenation by face-mask oxygen breathing in all patients undergoing GA and the maintenance of oxygenation throughout AM; the controlled technique using gentle, pressure-controlled MV with oxygen should be considered for patients requiring RSI. When CP is used during RSI and interferes with airway interventions, it should be partially or completely released enabling successful AM.
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