Luecke Thomas, Roth Harry, Herrmann Peter, Joachim Alf, Weisser Gerald, Pelosi Paolo, Quintel Michael
Department of Anesthesiology and Critical Care Medicine, Faculty of Clinical Medicine, University Hospital, Theodor-Kutzer-Ufer, 68167, Mannheim, Germany.
Intensive Care Med. 2003 Nov;29(11):2026-33. doi: 10.1007/s00134-003-1906-9. Epub 2003 Jul 25.
To examine the effects of positive end-expiratory pressure (PEEP) on extravascular lung water (EVLW), lung tissue, and lung volume.
Experimental animal study at a university research facility.
Fifteen adult sheep.
All animals were studied before and after saline washout-induced lung injury while ventilated with sequentially increasing PEEP (0, 7, 14, or 21 cmH(2)O).
Lung volume was determined by computed tomography and EVLW by the thermal dye dilution technique. Saline washout significantly increased lung tissue volume (21+/-3 to 37+/-5 ml/kg) and EVLW (9+/-2 to 36+/-9 ml/kg). While increasing levels of PEEP reduced EVLW (30+/-7, 24+/-8, and 18+/-4 ml/kg), lung tissue volume remained constant. Total lung volume significantly increased (50+/-8 ml/kg at PEEP 0 to 77+/-12 ml/kg at PEEP 21). Nonaerated lung volume significantly decreased and was closely correlated with the changes in EVLW ( r=0.67). In addition, a highly significant correlation was found between PEEP-induced decrease in nonaerated lung volume and decrease in transpulmonary shunt ( r=0.83).
The main findings are as follows: (a) PEEP effectively decreases EVLW. (b) The decrease in EVLW is closely correlated with the PEEP-induced decrease in nonaerated lung volume, making EVLW a valuable bedside parameter indicating alveolar recruitment, similar to measurements of transpulmonary shunt. (c) As excess tissue volume remained constant, however, EVLW may not be suitable to reflect overall severity of lung disease
探讨呼气末正压（PEEP）对血管外肺水（EVLW）、肺组织及肺容积的影响。
在大学研究机构进行的实验动物研究。
15只成年绵羊。
所有动物在生理盐水冲洗诱导的肺损伤前后进行研究，通气时依次增加PEEP（0、7、14或21 cmH₂O）。
通过计算机断层扫描测定肺容积，通过热染料稀释技术测定EVLW。生理盐水冲洗显著增加了肺组织容积（从21±3 ml/kg增加到37±5 ml/kg）和EVLW（从9±2 ml/kg增加到36±9 ml/kg）。虽然增加PEEP水平可降低EVLW（分别为30±7、24±8和18±4 ml/kg），但肺组织容积保持不变。总肺容积显著增加（PEEP为0时为50±8 ml/kg，PEEP为21时为77±12 ml/kg）。无气肺容积显著减少，且与EVLW的变化密切相关（r = 0.67）。此外，发现PEEP引起的无气肺容积减少与肺内分流减少之间存在高度显著的相关性（r = 0.83）。
主要发现如下：（a）PEEP有效降低EVLW。（b）EVLW的降低与PEEP引起的无气肺容积减少密切相关，使EVLW成为一个有价值的床边参数，可指示肺泡复张，类似于肺内分流的测量。（c）然而，由于多余的组织容积保持不变，EVLW可能不适合反映肺部疾病的总体严重程度
