Noninvasive continuous arterial pressure measurements in the assessment of acute, severe central hypovolemia

Abstract

Acute, severe hypovolemia is a medical emergency. Traditional vital sign parameters allow no optimal triage. High predictive power of finger plethysmography-based stroke volume (SV) and pulse pressure (PP) was recently suggested. To assess the performance of the PP and SV parameters, lower body negative pressure of -40 mmHg, than -60 mmHg -corresponding to moderate and severe central hypovolemia -was applied in 22 healthy males (age 35 ± 7 years). Slow breathing induced fluctuations in the above indices, characterized by stroke volume variability (SVV), and pulse pressure variability (PPV), were assessed. Responses in heart rate (HR) and shock index (SI) were also studied. Discriminative capacity of these parameters was characterized by the area under the ROC (receiver operating characteristic) curves (AUC). Results: In comparison of baseline to severe central hypovolemia SV, PP, HR and SI showed good discriminating capacity (AUC 99%, 88%, 87% and 93%, respectively). The discriminating capacity of SVV and PPV was poor (77% and 70%, respectively). In comparison of moderate and severe hypovolemia, the discriminating capacity of the studied parameters was uniformly limited. Conclusions: Plethysmography-based SV and PP parameters can be used to detect acute severe volume loss. Sensitive parameters discriminating moderate and severe central hypovolemia are still lacking.

Support Vector Machine Based Monitoring of Cardio-Cerebrovascular Reserve during Simulated Hemorrhage

“…Hypovolemic shock is the hemodynamic response to a critically reduced central blood volume (CBV) and its diagnosis has challenged clinicians since the Second World War (Grant and Reeve, 1941 ; Secher and Van Lieshout, 2016 ). The main treatment consists of intravenous volume administration (Secher and Van Lieshout, 2005 ) to raise cardiac output (CO) and improve microvascular blood flow (Vincent and De Backer, 2013 ; Perner and De Backer, 2014 ; Secher and Van Lieshout, 2016 ) and tissue oxygen delivery (Zollei et al, 2013 ; Simon et al, 2015 ). However, detection of a clinically relevant blood volume deficit remains difficult (Marik et al, 2011 ; Vincent and De Backer, 2013 ; Bronzwaer et al, 2015 ; Secher and Van Lieshout, 2016 ) because the blood volume is not only characterized by its magnitude but also by its function as preload to the heart (Marik et al, 2011 ; Bronzwaer et al, 2015 ; Secher and Van Lieshout, 2016 ).…”