Orsborn Jonathan, Graham James, Moss Michele, Melguizo Maria, Nick Todd, Stroud Michael
From the *Department of Pediatrics, Section of Emergency Medicine, †College of Medicine, ‡Department of Pediatrics, Section of Critical Care, and §Department of Pediatrics, Biostatistics Program, University of Arkansas for Medical Sciences, Arkansas Children's Hospital, Little Rock, AR.
Pediatr Emerg Care. 2016 Jan;32(1):20-2. doi: 10.1097/PEC.0000000000000365.
Cuffed endotracheal tubes (ETTs) are frequently used in children, allowing fewer air leaks and helping prevent ventilator-associated pneumonia. Tracheal mucosal perfusion is compromised at an ETT cuff pressure (ETTCP) of 30 cm H2O with blood flow completely absent above 50 cm H2O. Our objective was to compare multiple pediatric-sized ETTCPs at ground level and various altitudes during aeromedical transport.
Simulating the transport environment, 4 pediatric-sized mannequin heads were intubated with appropriately sized cuffed ETTs (3.0, 4.0, 5.0, 6.0) and transported by helicopter or nonpressurized fixed-wing aircraft 20 times each. The ETTCP was set to 10 cm H2O before transport, and the pressure was measured with a standard manometer at 1000-ft intervals until reaching peak altitude or CP greater than 60 cm H2O. Ground elevation ranged from 400-650 ft mean sea level (MSL) and peak altitude from 3500 to 5000 ft MSL.
Increased altitude caused a significant increase in ETTCP of all ETT sizes (P < 0.001). However, there is no statistical difference in pressures between ETT sizes (P = 0.28). On average, ETTCP in 3.0, 4.0, and 6.0 ETTs surpassed 30 cm H2O at approximately 1500 ft MSL and 50 cm H2O at approximately 2800 ft MSL. In the 5.0 ETT, the CP reached 30 cm H2O at 2000 ft MSL and 50 cm H2O at 3700 ft MSL.
The ETTCP in pediatric-sized ETTs regularly exceed recommended pressure limits at relatively low altitudes. There is no additional pressure increase related to ETT size. This has the potential to decrease mucosal blood flow, possibly increasing risk of subsequent tracheal stenosis, rupture, and other complications.
带套囊气管内插管（ETT）常用于儿童，可减少漏气并有助于预防呼吸机相关性肺炎。当ETT套囊压力（ETTCP）达到30 cm H₂O时，气管黏膜灌注会受到影响，而当压力高于50 cm H₂O时血流会完全停止。我们的目的是比较航空医疗转运期间地面及不同海拔高度下多种儿童尺寸ETT的ETTCP。
模拟转运环境，为4个儿童尺寸的人体模型头部插入尺寸合适的带套囊ETT（3.0、4.0、5.0、6.0），并分别用直升机或非加压固定翼飞机各转运20次。转运前将ETTCP设置为10 cm H₂O，每隔1000英尺用标准压力计测量压力，直至达到最高海拔或CP大于60 cm H₂O。地面海拔范围为平均海平面（MSL）400 - 650英尺，最高海拔为MSL 3500至5000英尺。
海拔升高导致所有ETT尺寸的ETTCP显著增加（P < 0.001）。然而，不同ETT尺寸之间的压力无统计学差异（P = 0.28）。平均而言，3.0、4.0和6.0 ETT的ETTCP在约1500英尺MSL时超过30 cm H₂O，在约2800英尺MSL时超过50 cm H₂O。在5.0 ETT中，CP在2000英尺MSL时达到30 cm H₂O，在3700英尺MSL时达到50 cm H₂O。
儿童尺寸ETT的ETTCP在相对较低海拔时经常超过推荐压力限值。压力增加与ETT尺寸无关。这有可能减少黏膜血流，可能增加后续气管狭窄、破裂及其他并发症的风险。
