Background: Microcirculatory driving pressure is defined as the difference between post-arteriolar and venular\r\npressure. In previous research, an absence of correlation between mean arterial blood pressure (MAP) and\r\nmicrocirculatory perfusion has been observed. However, the microcirculation may be considered as a low pressure\r\ncompartment with capillary pressure closer to venous than to arterial pressure. From this perspective, it is\r\nconceivable that central venous pressure (CVP) plays a more important role in determination of capillary perfusion.\r\nWe aimed to explore associations between CVP and microcirculatory perfusion.\r\nMethods: We performed a post-hoc analysis of a prospective study in septic patients who were resuscitated\r\naccording a strict non-CVP guided treatment protocol. Simultaneous measurements of hemodynamics and\r\nsublingual Sidestream Dark Field imaging were obtained 0 and 30 minutes after fulfillment of resuscitation goals.\r\nData were examined for differences in microcirculatory variables for CVP = or > 12 mmHg and its evolution over\r\ntime, as well as for predictors of a microvascular flow index (MFI) < 2.6.\r\nResults: In 70 patients with a mean APACHE II score of 21, 140 simultaneous measurements of CVP and sublingual\r\nmicrocirculation (vessels < 20 Ã?µmeter) were obtained. (MFI) and the percentage of perfused small vessels (PPV)\r\nwere significantly lower in the ââ?¬Ë?highââ?¬â?¢ CVP (> 12 mmHg) group as compared to patients in the ââ?¬Ë?lowââ?¬â?¢ CVP\r\n(=12 mmHg) group (1.4 Ã?± 0.9 vs. 1.9 Ã?± 0.9, P = 0.006; and 88 Ã?± 21% vs. 95 Ã?± 8%, P = 0.006 respectively). Perfusion\r\npressure (MAPââ?¬â??CVP) and cardiac output did not differ significantly between both CVP groups. From time point 0 to\r\n30 minutes, a significant increase in MFI (from 1.6 Ã?± 0.6 to 1.8 Ã?± 0.9, P = 0.027) but not in PPV, was observed, while\r\nCVP and perfusion pressure significantly decreased in the same period. In a multivariate model CVP > 12 mmHg\r\nwas the only significant predictor for a capillary MFI < 2.6 (Odds ratio 2.5 (95% confidence interval 1.1-5.8),\r\nP = 0.026).\r\nConclusion: We observed a significant association between a higher CVP and impairment of microcirculatory blood\r\nflow. Further research is needed to elaborate on our hypothesis generating findings that an elevated CVP may act\r\nas an outflow obstruction of organ perfusion
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