Lenique F, Habis M, Lofaso F, Dubois-Randé J L, Harf A, Brochard L
Physiology Departement, INSERM U296, Henri-Mondor Hospital, Créteil, France.
Am J Respir Crit Care Med. 1997 Feb;155(2):500-5. doi: 10.1164/ajrccm.155.2.9032185.
The ventilatory and hemodynamic effects of continuous positive airway pressure (CPAP) delivered via a face mask (at 0, 5, and 10 cm H2O, and after a return to 0 cm H2O) were studied in nine patients with acute left heart failure (pulmonary artery occlusion pressure [PAOP] > or = 18 mm Hg, and cardiac index [CI] < or = 2.8 L/min/m2). CPAP at 10 cm H2O induced an improvement in lung compliance (60 +/- 10 ml/cm H2O to 87 +/- 20 ml/cm H2O, p < 0.05) and in lung and airway resistance (5.7 +/- 1.0 cm H2O/L/s to 3.4 +/- 1.0 cm H2O/L/s, p < 0.05), a reduction in work of breathing (18 +/- 3 J/min to 12 +/- 2 J/min, p < 0.05), and in the pressure-time index of the respiratory muscles (279 +/- 22 cm H2O/s/min to 174 +/- 25 cm H2O/s/min, p < 0.05), without significant changes in breathing pattern. Despite a significant reduction in the negative swings in intrathoracic pressure (15.2 +/- 1.9 cm H2O to 10.8 +/- 1.8 cm H2O, p < 0.001), no significant change was observed in CI or stroke volume during CPAP. However, mean transmural filling pressures decreased significantly with CPAP, suggesting a better cardiac performance. Neither the level of stroke volume nor of PAOP, was predictive of changes in CI or in stroke volume. In patients with respiratory insufficiency caused by congestive heart failure (CHF), CPAP reduces respiratory muscle effort without altering cardiac output. The slight decrease in mean transmural left and right atrial pressures suggests an improvement in cardiac performance.
对9例急性左心衰竭患者（肺动脉闭塞压[PAOP]≥18mmHg，心脏指数[CI]≤2.8L/min/m²）进行了研究，观察通过面罩给予持续气道正压通气（CPAP）（压力分别为0、5和10cmH₂O，之后恢复到0cmH₂O）对通气和血流动力学的影响。10cmH₂O的CPAP可使肺顺应性改善（从60±10ml/cmH₂O提高到87±20ml/cmH₂O，p<0.05），肺和气道阻力降低（从5.7±1.0cmH₂O/L/s降至3.4±1.0cmH₂O/L/s，p<0.05），呼吸功减少（从18±3J/min降至12±2J/min，p<0.05），呼吸肌压力-时间指数降低（从279±22cmH₂O/s/min降至174±25cmH₂O/s/min，p<0.05），而呼吸模式无显著变化。尽管胸腔内压力的负向波动显著降低（从15.2±1.9cmH₂O降至10.8±1.8cmH₂O，p<0.001），但CPAP期间CI或每搏量无显著变化。然而，CPAP时平均跨壁充盈压显著降低，提示心脏功能改善。每搏量水平和PAOP均不能预测CI或每搏量的变化。在因充血性心力衰竭（CHF）导致呼吸功能不全的患者中，CPAP可减少呼吸肌做功而不改变心输出量。平均跨壁左、右心房压力的轻微降低提示心脏功能有所改善。
