超声心动图自动边缘检测评价呼气末正压对心功能的影响

本研究应用超声心动图自动边缘检测(ABD)新技术,对呼气末正压(PEEP)时,左、右心室心功能各参数的观察发现,尽管PEEP会降低左、右心室的前负荷,但合理掌握则有利于肺水肿病人的治疗。

ECHOCARDIOGRAPHIC AUTOMATIC BORDER DETECTION FOR MONITORING CARDIAC FUNCTION DURING THE POSITIVE END-EXPIRATORY PRESSURE

Recently, an automated endocardial border detection (ABD) algorithm producing a continuous graphic display of changes in ventricular area was incorporated into standard echocardiographic equipment. Our purpose was to evaluate the clinical application of ABD for monitoring left and right ventricular cavity area during the positive pressure (PEEP) ventilation. An apical four chamber view was obtained in 8 patients after valvular replacement in 48h, Lateral gain compensations and transmit powers were adjusted to minimize cavity noise while border definition was maintained in constant position during mechanical ventilation in the presence of 0, 0.89, 0.59 and 0.98kPa PEEP. Measurements included: left ventricular (LV) and right ventricular (RV) end-diastolic area (EDA), end-systolic area (ESA), fractional area change (FAC), difference between EDA and ESA (EDA-ESA), peak filling rate (PFR) and peak ejection rate (PER).Results: LV-EDA decreased progressively with increasing PEEP level:When PEEP wag at 0.59kPa level, LV-FAC, LV-PER and LV-PFR were dramatically elevated and reached to the maximum value. ESA decreased remarkably which kept EDA-ESA at original level. RV-EDA decreased progressively with increasing PE EP level. RV-FAO was not related to PEEP level. RV-PER and RV-PFR were increased at 0.59kPa PEEP level. EDA-ESA reduced when PEEP was at 0.59and0.98kPa.Conclusion: PEEP has the effects of: 1. decreasing left and right ventricular preload but undeteriorating its output; 2. maintaining left and right ventricular contractility when PEEP is less than 0:98 kPa; 3. PER and PFR are at their peek level when PEEP is at 0.69kPa, which is the optimal level for treatment of pulmonary edema. This new application of ABD endows echocardiography with quantitative power sufficient to monitor ventricular performance.