Pulse pressure variation and volume responsiveness during acutely increased pulmonary artery pressure: an experimental study

Abstract

IntroductionWe found that pulse pressure variation (PPV) did not predict volume responsiveness in patients with increased pulmonary artery pressure. This study tests the hypothesis that PPV does not predict fluid responsiveness during an endotoxin-induced acute increase in pulmonary artery pressure and right ventricular loading.MethodsPigs were subjected to endotoxemia (0.4 μg/kg/hour lipopolysaccharide), followed by volume expansion, subsequent hemorrhage (20% of estimated blood volume), retransfusion, and additional stepwise volume loading until cardiac output did not increase further (n = 5). A separate control group (n = 7) was subjected to bleeding, retransfusion, and volume expansion without endotoxemia. Systemic hemodynamics were measured at baseline and after each intervention, and PPV was calculated offline. Prediction of fluid-challenge-induced stroke volume increase by PPV was analyzed using receiver operating characteristic (ROC) curves.ResultsSixty-eight volume challenges were performed in endotoxemic animals (22 before and 46 after hemorrhage), and 51 volume challenges in the controls. Endotoxin infusion resulted in an acute increase in pulmonary artery and central venous pressure and a decrease in stroke volume (all P < 0.05). In endotoxemia, 68% of volume challenges before hemorrhage increased the stroke volume by > 10%, but PPV did not predict fluid responsiveness (area under the ROC curve = 0.604, P = 0.461). After hemorrhage in endotoxemia, stroke volume increased in 48% and the predictive value of PPV improved (area under the ROC curve for PPV = 0.699, P = 0.021). In controls after hemorrhage, stroke volume increased in 67% of volume challenges and PPV was a predictor of fluid responsiveness (area under the ROC curve = 0.790, P = 0.001).ConclusionsFluid responsiveness cannot be predicted with PPV during acute pulmonary hypertension in porcine endotoxemia. Even following severe hemorrhage during endotoxemia, the predictive value of PPV is marginal.

Pulse Pressure Variation Is Comparable With Central Venous Pressure to Guide Fluid Resuscitation in Experimental Hemorrhagic Shock With Endotoxemia

“…The resulting AUC for PPV was lower than reported in some studies (6,7), but similar to others (19,20,22), its value bordering the acceptable limit of a biomarker (20,29). The cutoff value chosen for PPV (13%) was based on previous findings (6), but the adjustment of PPV to the ideal cutoff value of 15%, in a posterior analysis, improved specificity and resulted in considerably lower incidence of false-positive results.…”

Management of Crashing Patients with Pulmonary Hypertension

“…Traditional methods of assessing fluid responsiveness, such as central venous pressure, pulse pressure variation, and stroke volume variation, are unreliable in patients with RV dysfunction. 62,63 Elevation in plasma atrial natriuretic peptide and BNP seems to increase proportionately to the extent of RV dysfunction in patients with PH. 54,64 The traditional gold standard for the diagnosis and management of PH and RV dysfunction is pulmonary artery catheterization (PAC).…”

A pathophysiological approach towards right ventricular function and failure

“…Although generally a useful indicator of fluid responsiveness, 70,71 pulse pressure variation cannot be used reliably in the setting of RV failure, and the lack of a decrease in high pulse pressure variations after fluid administration has been suggested as a diagnostic tool for RV failure. [72][73][74] Echocardiographically guided volume challenges may provide an adequate therapeutic approach, for example by measuring vena cava diameters.…”