Greenstein Yonatan Y, Shakespeare Eric, Doelken Peter, Mayo Paul H
*Department of Medicine, Hofstra Northwell School of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, New Hyde Park ‡Department of Medicine, Albany Medical Center, Albany, NY †Department of Medicine, Einstein Healthcare Network, East Norriton, PA.
J Bronchology Interv Pulmonol. 2017 Jul;24(3):206-210. doi: 10.1097/LBR.0000000000000367.
Flexible bronchoscopy (FB) in intubated patients on mechanical ventilation increases airway resistance. During FB, two ventilatory strategies are possible: maintaining tidal volume (VT) while maintaining baseline CO2 or allowing reduction of VT. The former strategy carries risk of hyperinflation due to expiratory flow limitation with FB. The aim of the authors was too study end expiratory lung volume (EELV) during FB of intubated subjects while limiting VT.
We studied 16 subjects who were intubated on mechanical ventilation and required FB. Changes in EELV were measured by respiratory inductance plethysmography. Ventilator mechanics, EELV, and arterial blood gases, were measured.
FB insertions decreased EELV in 64% of cases (-325±371 mL) and increased it in 32% of cases (65±59 mL). Suctioning decreased EELV in 76% of cases (-120±104 mL) and increased it in 16% of cases (29±33 mL). Respiratory mechanics were unchanged. Pre-FB and post-FB, PaO2 decreased by 61±96 mm Hg and PaCO2 increased by 15±7 mm Hg.
There was no clinically significant increase in EELV in any subject during FB. Decreases in EELV coincided with FB-suctioning maneuvers. Peak pressure limiting ventilation protected the subject against hyperinflation with a consequent, well-tolerated reduction in VT, and hypercapnea. Suctioning should be limited, especially in patients vulnerable to derecruitment effect.
对机械通气的插管患者进行可弯曲支气管镜检查（FB）会增加气道阻力。在FB期间，有两种通气策略可行：维持潮气量（VT）同时维持基线二氧化碳水平或允许VT降低。前一种策略因FB导致呼气流量受限而存在肺过度充气的风险。作者的目的是在限制VT的情况下研究插管受试者FB期间的呼气末肺容积（EELV）。
我们研究了16名接受机械通气且需要进行FB的受试者。通过呼吸感应体积描记法测量EELV的变化。测量通气力学、EELV和动脉血气。
FB插入操作使64%的病例EELV降低（-325±371 mL），32%的病例EELV升高（65±59 mL）。吸痰使76%的病例EELV降低（-120±104 mL），16%的病例EELV升高（29±33 mL）。呼吸力学未改变。FB前和FB后，动脉血氧分压（PaO2）降低61±96 mmHg，动脉血二氧化碳分压（PaCO2）升高15±7 mmHg。
在任何受试者的FB期间，EELV均未出现具有临床意义的增加。EELV降低与FB - 吸痰操作同时出现。限制峰值压力通气可保护受试者避免肺过度充气，从而使VT得到良好耐受的降低，并避免高碳酸血症。应限制吸痰，尤其是对于易受肺不张影响的患者。
