Chhibber A K, Fickling K, Kolano J W, Roberts W A
Department of Anesthesiology, University of Rochester Medical Center, New York 14642, USA.
Anesth Analg. 1997 Jan;84(1):51-3. doi: 10.1097/00000539-199701000-00009.
The laryngeal mask airway (LMA) has become a popular tool for airway management in selected adult and pediatric patients undergoing routine surgical procedures. The relationship between end-tidal and arterial carbon dioxide during controlled ventilation via the LMA in infants under 10 kg has not been reported. After induction of general anesthesia, the LMA was placed in 12 healthy infants and mechanical ventilation initiated. After maintaining steady-state level of end-tidal carbon dioxide (minimum 5 min), an arterial blood sample was obtained and end-tidal carbon dioxide level noted. The laryngeal mask was then removed, the trachea intubated, and mechanical ventilation resumed with initial ventilatory variables. After reaching a steady-state level of end-tidal carbon dioxide, a second arterial sample was obtained and end-tidal carbon dioxide level noted. The mean end-tidal carbon dioxide and arterial partial pressure of carbon dioxide obtained during ventilation were 42.2 +/- 7.9 and 47.1 +/- 11.0 (LMA) and 37.4 +/- 4.6 and 42.6 +/- 6.7 (endotracheal tube), respectively. Analysis of differences between partial pressure of carbon dioxide and end-tidal carbon dioxide using the Bland and Altman method revealed bias+/-precision of 4.9 +/- 3.9 and 5.3 +/- 3.2 with ventilation via the laryngeal mask and endotracheal tube. Our data indicate that, while ventilating infants under 10 kg with LMA, end-tidal carbon dioxide is an accurate indicator of arterial partial pressure of carbon dioxide.
喉罩气道（LMA）已成为在接受常规外科手术的特定成人和儿科患者中进行气道管理的常用工具。关于体重不足10公斤的婴儿通过LMA进行控制通气时呼气末二氧化碳与动脉二氧化碳之间的关系尚未见报道。全身麻醉诱导后，将LMA放置在12名健康婴儿中并开始机械通气。在维持呼气末二氧化碳的稳态水平（至少5分钟）后，采集动脉血样本并记录呼气末二氧化碳水平。然后移除喉罩，气管插管，并以初始通气变量恢复机械通气。在达到呼气末二氧化碳的稳态水平后，采集第二份动脉样本并记录呼气末二氧化碳水平。通气期间获得的平均呼气末二氧化碳和动脉二氧化碳分压分别为42.2±7.9和47.1±11.0（LMA）以及37.4±4.6和42.6±6.7（气管内导管）。使用Bland和Altman方法分析二氧化碳分压与呼气末二氧化碳之间的差异，结果显示通过喉罩和气管内导管通气时的偏差±精密度分别为4.9±3.9和5.3±3.2。我们的数据表明，在使用LMA对体重不足10公斤的婴儿进行通气时，呼气末二氧化碳是动脉二氧化碳分压的准确指标。
