持续气道正压通气对急性心源性肺水肿犬呼吸及循环功能的影响

目的研究持续气道正压(CPAP)通气对急性心源性肺水肿(ACPE)犬呼吸及循环功能的影响。方法分别监测10条犬健康状态及ACPE发生后自主呼吸、5cmH2O(1cmH2O=0.098kPa)、10cmH2O、15cmH2OCPAP时的胸腔负压(Pt)、中心静脉压(CVP)、心输出量(CO)、平均动脉压(BPm)、肺动脉楔压(PAWP)。结果与健康状态相比,ACPE犬呼吸增强、增快,Pt由-(4.90±0.09)cmH2O上升至-(10.90±0.75)cmH2O,CVP由(10.1±0.4)mmHg下降至(8.0±0.7)mmHg,CO由(1.52±0.13)L/min下降至(0.85±0.09)L/min,PAWP升高(P均<0.05)。CVP与Pt变化呈正相关(r=0.78,P<0.01)。5及10cmH2OCPAP时Pt值恢复至-(6.53±0.11)cmH2O和-(5.14±0.25)cmH2O,呼吸形式基本恢复正常,CVP升至(11.6±0.7)mmHg和(14.2±0.2)mmHg,CO增加至(1.45±0.11)L/min和(1.24±0.11)L/min,其中5cmH2OCPAP组PAWP下降(P均<0.05)。15cmH2OCPAP时,呼吸浅快,Pt为-(0.82±0.37)cmH2O,CO为(0.82±0.07)L/min,其他血流动力学指标皆恶化(P均<0.05)。结论犬ACPE发生时,呼吸运动显著增强,Pt升高,并导致CVP和CO的下降;适当CPAP通过改善呼吸功能,调节Pt改善ACPE犬的心功能。

Ventilatory and hemodynamic effects of continuous positive airway pressure in dogs with acute cardiogenic pulmonary edema

OBJECTIVE: To investigate the ventilatory and hemodynamic effects of continuous positive airway pressure (CPAP) in acute cardiogenic pulmonary edema (ACPE) in dogs. METHODS: Cardiac output (CO), heart rate (HR), blood pressure (BP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP) and intrathoracic negative pressure (Pt) were measured. These parameters were recorded at spontaneous breath, 5 cm H2O, 10 cm H2O, and 15 cm H2O CPAP in ten dogs before (healthy state) and after the induction of ACPE. RESULTS: When ACPE occurred, the dogs showed rapid breath, higher Pt [-(10.90 +/- 0.75) versus -(4.90 +/- 0.09) cm H2O], decreased CVP and CO [(10.1 +/- 0.4) versus (8.0 +/- 0.7) mm Hg and (1.52 +/- 0.13) versus (0.85 +/- 0.09) L/min, respectively], increased PAWP [(9.64 +/- 0.54) versus (17.77 +/- 0.79) mm Hg, all P < 0.05]. The correlation coefficient of the change of CVP and the change of Pt was 0.78 (P < 0.01). The addition of 5 or 10 cm H2O CPAP decreased Pt [-(6.53 +/- 0.11), -(5.14 +/- 0.25) cm H2O], which resulted in increased cardiac function. CO was also increased [(1.45 +/- 0.11), (1.24 +/- 0.11) L/min], with decreased PAWP [(15.80 +/- 0.55), (17.40 +/- 0.70) mm Hg; P < 0.05]. After the application of 15 cm H2O CPAP, Pt reached nearly zero [-(0.82 +/- 0.37) cm H2O], CO decreased to (0.82 +/- 0.07) L/min and PAWP increased to (19.23 +/- 0.73) mm Hg (P < 0.05). CONCLUSIONS: ACPE induced rapid breath, elevated Pt and decreased CVP and CO. Proper CPAP can improve CO by regulating Pt, hence the improvement of other hemodynamic parameters.