Dambrosio M, Cinnella G, Brienza N, Ranieri V M, Giuliani R, Bruno F, Fiore T, Brienza A
Istituto di Anestesiologia e Rianimazione, Università degli Studi di Bari, Italy.
Intensive Care Med. 1996 Sep;22(9):923-32. doi: 10.1007/BF02044117.
To examine the effects of external positive end-expiratory pressure (PEEP) on right ventricular function in chronic obstructive pulmonary disease (COPD) patients with intrinsic PEEP (PEEPi).
Prospective study.
General intensive care unit in a university teaching hospital.
Seven mechanically ventilated flow-limited COPD patients (PEEPi = 9.7 +/- 1.3 cmH2O, mean +/- SD) with acute respiratory failure.
Hemodynamic and respiratory mechanic data were collected at four different levels of PEEP (0-5-10-15 cmH2O).
Hemodynamic parameters were obtained by a Swan-Ganz catheter with a fast response thermistor. Cardiac index (CI) and end-expiratory lung volume (EELV) reductions started simultaneously when the applied PEEP was approximately 90% of PEEPi measured on 0 cmH2O (ZEEP). Changes in transmural intrathoracic pressure (PEEPi,cw) started only at a PEEP value much higher (120%) than PEEPi. The reduction in CI was related to a decrease in the right end-diastolic ventricular volume index (RVEDVI) (r = 0.61; p < 0.001). No correlation between CI and transmural right atrial pressure was observed. The RVEDVI was inversely correlated with PEEP-induced changes in EELV (r = -55; p < 0.001), but no with PEEPi,cw (r = -0.08; NS). The relationship between RVEDVI and right ventricular stroke work index, considered an index of contractility, was significant in three patients, i.e., PEEP did not change contractility. In the other patients, an increase in contractility seemed to occur.
In COPD patients an external PEEP exceeding 90% of PEEPi causes lung hyperinflation and reduces the CI due to a preload effect. The reduction in RVEDVI seems related to changes in EELV, rather than to changes in transmural pressures, suggesting a lung/heart volume interaction in the cardiac fossa. Thus, in COPD patients, application of an external PEEP level lower than PEEPi may affect right ventricular function.
探讨呼气末正压通气（PEEP）对存在内源性呼气末正压（PEEPi）的慢性阻塞性肺疾病（COPD）患者右心室功能的影响。
前瞻性研究。
一所大学教学医院的综合重症监护病房。
7例因急性呼吸衰竭接受机械通气的流量受限型COPD患者（PEEPi = 9.7±1.3 cmH₂O，均值±标准差）。
在四个不同的PEEP水平（0 - 5 - 10 - 15 cmH₂O）收集血流动力学和呼吸力学数据。
通过带有快速响应热敏电阻的Swan - Ganz导管获取血流动力学参数。当所施加的PEEP约为在0 cmH₂O（ZEEP）时测得的PEEPi的90%时，心脏指数（CI）和呼气末肺容积（EELV）同时开始降低。跨壁胸腔内压力（PEEPi,cw）的变化仅在PEEP值远高于（120%）PEEPi时才开始。CI的降低与右心室舒张末期容积指数（RVEDVI）的降低相关（r = 0.61；p < 0.001）。未观察到CI与跨壁右心房压力之间的相关性。RVEDVI与PEEP引起的EELV变化呈负相关（r = - 55；p < 0.001），但与PEEPi,cw无相关性（r = - 0.08；无统计学意义）。在3例患者中，RVEDVI与被视为收缩性指标的右心室每搏功指数之间的关系显著，即PEEP未改变收缩性。在其他患者中，似乎出现了收缩性增加。
在COPD患者中，超过PEEPi 90%的外部PEEP会导致肺过度充气，并由于前负荷效应而降低CI。RVEDVI的降低似乎与EELV的变化有关，而非与跨壁压力的变化有关，提示心脏窝内存在肺/心脏容积相互作用。因此，在COPD患者中，应用低于PEEPi的外部PEEP水平可能会影响右心室功能。
