The changes of endotracheal tube intracuff pressures after ear and head and neck surgery-related positions: a prospective observational study

Abstract Introduction The cuff of an endotracheal tube seals the airway to facilitate positive-pressure ventilation and reduce subglottic secretion aspiration. However, an increase or decrease in endotracheal tube intracuff pressure can lead to many morbidities. Objective The main purpose of this study is to investigate the effect of different head and neck positions on endotracheal tube intracuff pressure during ear and head and neck surgeries. Methods A total of 90 patients undergoing elective right ear (Group 1: n = 30), left ear (Group 2: n = 30) or head and neck (Group 3: n = 30) surgery were involved in the study. A standardized general anesthetic was given and cuffed endotracheal tubes by the assistance of video laryngoscope were placed in all patients. The pilot balloon of each endotracheal tube was connected to the pressure transducer and standard invasive pressure monitoring was set to measure intracuff pressure values continuously. The first intracuff pressure value was adjusted to 18.4 mmHg (25 cm H2O) at supine and neutral neck position. The patients then were given appropriate head and neck positions before related-surgery started. These positions were left rotation, right rotation and extension by under-shoulder pillow with left/right rotation for Groups 1, 2 and 3, respectively. The intracuff pressures were measured and noted after each position, at 15th, 30th, 60th, 90th minutes and before the extubation. If intracuff pressure deviated from the targeted value of 20-30 cm H2O at anytime, it was set to 25 cm H2O again. Results The intracuff pressure values were increased from 25 to 26.73 (25-28.61) cm H2O after left neck rotation (p = 0.009) and from 25 to 27.20 (25.52-28.67) cm H2O after right neck rotation (p = 0.012) in Groups 1 and 2, respectively. In Group 3, intracuff pressure values at the neutral position, after extension by under-shoulder pillow and left or right rotation were 25, 29.41 (27.02-36.94) and 34.55 (28.43-37.31) cm H2O, respectively. There were significant differences between the neutral position and extension by under-shoulder pillow (p < 0.001), and also between neutral position and rotation after extension (p < 0.001). However, there was no statistically significant increase of intracuff pressure between extension by under-shoulder pillow and neck rotation after extension positions (p = 0.033). Conclusion Accessing the continuous intracuff pressure value measurements before and during ear and head and neck surgeries is beneficial to avoid possible adverse effects/complications of surgical position-related pressure changes.

摘要 引言
气管导管（endotracheal tube）套囊可封闭气道，以辅助正压通气并减少声门下分泌物误吸。然而，气管导管气囊内压（intracuff pressure）的升高或降低可引发多种不良事件。
【研究目的】本研究旨在探讨耳科及头颈部手术期间，不同头颈部体位对气管导管气囊内压的影响。
【研究方法】本研究共纳入90例行择期手术的患者，其中行右侧耳科手术者为第1组（n=30）、左侧耳科手术者为第2组（n=30）、头颈部手术者为第3组（n=30）。所有患者均接受标准化全身麻醉，并通过视频喉镜（video laryngoscope）置入带套囊的气管导管。将每根气管导管的套囊测压球囊连接至压力传感器（pressure transducer），并设置标准有创压力监测以持续采集气囊内压数值。在患者取仰卧位且颈部处于中立位时，将初始气囊内压调整至18.4 mmHg（等效25 cm H₂O）。随后在手术开始前，为各组患者调整至对应手术所需的头颈部体位：第1组为颈部左侧旋转，第2组为颈部右侧旋转，第3组为肩下垫枕后行颈部过伸并配合左右旋转。分别在体位调整后、手术开始后第15、30、60、90分钟以及拔管前测量并记录气囊内压。若任意时刻气囊内压偏离目标范围20~30 cm H₂O，需重新调整至25 cm H₂O。
【研究结果】第1组患者颈部左侧旋转后，气囊内压从25 cm H₂O升至26.73（25~28.61）cm H₂O（p=0.009）；第2组患者颈部右侧旋转后，气囊内压从25 cm H₂O升至27.20（25.52~28.67）cm H₂O（p=0.012）。第3组患者在颈部中立位、肩下垫枕过伸位以及过伸后行左右旋转位时的气囊内压分别为25 cm H₂O、29.41（27.02~36.94）cm H₂O以及34.55（28.43~37.31）cm H₂O。颈部中立位与肩下垫枕过伸位的气囊内压差异具有统计学显著性（p<0.001），颈部中立位与过伸后旋转位的差异亦具有统计学显著性（p<0.001）。然而，肩下垫枕过伸位与过伸后颈部旋转位之间的气囊内压升高未呈现统计学显著性差异（p=0.033）。
【研究结论】在耳科及头颈部手术术前及术中持续监测气囊内压，有助于规避手术体位相关的压力变化所引发的潜在不良事件或并发症。