Effect of post recruitment maneuver ventilation by different tidal volume on lung vascular endothelial diastole function in rats with acute lung injury

BACKGROUND： This study aimed to observe the effect of recruitment maneuver （RM） and post-RM ventilation at different tidal volume on lung vascular diastole endothelial function in rats with acute lung injury （ALI）.METHODS： A ALl rat model was produced by intravenous infusion of lipopolysaccharide （6 mg/ kg）. Twenty-five rats were randomly divided into five groups： control group （n=5）, ALl group （n=5）, low tidal volume group （LV group, VT 6 mL/kg, n=5）, sustained inflation （SI） with low tidal volume group （SI＋LV group, VT 6 mL/kg, n=5）, and SI with moderate tidal volume group （SI＋MV group, VT 12 mL/ kg, n=5）. RM was performed with SI, airway pressure 30 cmH2O for 30 seconds, and positive end- expiratory pressure （PEEP） was set to 5 cmH2O. Lung tissue was taken after 5 hours of mechanical ventilation. Mean arterial blood pressure （MAP） was monitored during the experiment. Endothelin-1 （ET-1）, endothelial nitricoxide synthase （eNOS）, Ach-induced endothelium-dependent relaxation response of isolated pulmonary artery rings were determined at 5 hours. RESULTS：LPS increased ET-1 level, decreased the expression of eNOS in lung tissue, impaired the Ach-induced endothelium-dependent relaxation response in the pulmonary artery, without obvious effect on systemic hemodynamics. SI＋LV significantly reduced LPS-induced elevation of ET-1 level, increased the expression of eNOS, significantly improved endothelial dysfunction, and improved the dysfunction of endothelium-dependent relaxation in the pulmonary artery. CONCLUSIONS：RM with a high or low tidal volume ventilation could improve the lung vascular endothelial function of rats with acute lung injury, and RM with low tidal volume ventilation could lower significantly the injury of lung vascular endothelial diastole function in rats with acute lung injury.

Correlation between Diastolic Function and Mass and Geometry of Left Ventricle in Essential Hypertension

Object Diastolic function' s assessment is vital in order to produce information relevant to patients' functional class, management and prognosis. We sought to investigate diastolic dysfunction in essential hypertension (EH) with or without coronary heart disease (CAD) using color M - mode Doppler echocardiography and to study the relation between diastolic dysfunction and left ventricular mass index (LVMI) and geometry of LV, and to demonstrate partly the cause of increased cardiovascular risk of an echocardiographic pattern of LV geometry. Methods36 normal subjects (Group Ⅰ) and 107 patients with essential hypertension (Group II) were studied using color M - mode Doppler echocardiography. Four different LV anatomic adaptation to hypertension were i-dentified by categorizing patients according to values of end - diastolic relative wall thickness (RWT) and LVMI. We measured the rate of propagation of peak early filling flow velocity (Vp), time delay (TD) of the peak early filling flow velocity from mitral tips to the apex and Vp/E. Results The geometry of LV was classified into four types according to the LVMI and RWT. The normal limits of LVMI and RWT were obtained from the upper limits of the 95 % confidence interval from mean of LVMI and RWT in healthy control group respectively, which were 115.2 g/m2 and 0. 44. The definition of each type was as follows: Type I (normal group): LVMI≤115. 2 g/m2 and RWT≤ 0.44; Type Ⅱ (concentric remodeling): LVMI≤ 115. 2 g/m2 and RWT > 0. 44; Type III (eccentric hypertrophy): LVMI> 115.2 g/m2 and RWT≤0.44; Type Ⅳ (concentric hypertrophy): LVMI> 115.2 g/m2 and RWT>0.44. Most parameters of diastolic function in each geometry type differed significantly from those in the control group, but the difference among each geometry type was not significant. When compared with type Ⅰ, there was a tendency that TD was longer and Vp/E smaller in Type Ⅱ, Ⅲ and Ⅳ groups. The correlation between LVMI and Vp and TD had statistical significance ( P < 0. 01); the correlation coefficients were-0.21 and 0.29, respectively. Conclusions There is diastolic dysfunction in different LV geometry in patients with essential hypertension, even in patients with LV normal geometry there is diastolic dysfunction. LVMI has negative correlation to Vp, and positive correlation to TD. It may indicate that the greater the LVMI is, the worse the LV diastolic function.