Background: Different hemodynamic parameters including static indicators of cardiac preload as right ventricular end-diastolic volume index (RVEDVI) and dynamic parameters as pulse pressure variation (PPV) have been used in the decision-making process regarding volume expansion in critically ill patients. The objective of this study was to compare fluid resuscitation guided by either PPV or RVEDVI after experimentally induced hemorrhagic shock.
Methods: Twenty-six anesthetized and mechanically ventilated pigs were allocated into control (group I), PPV (group II), or RVEDVI (group III) group. Hemorrhagic shock was induced by blood withdrawal to target mean arterial pressure of 40 mm Hg, maintained for 60 minutes. Parameters were measured at baseline, time of shock, 60 minutes after shock, immediately after resuscitation with hydroxyethyl starch 6% (130/0.4), 1 hour and 2 hours thereafter. The endpoint of fluid resuscitation was determined as the baseline values of PPV and RVEDVI. Statistical analysis of data was based on analysis of variance for repeated measures followed by the Bonferroni test (p < 0.05).
Results: Volume and time to resuscitation were higher in group III than in group II (group III = 1,305 ± 331 mL and group II = 965 ± 245 mL, p < 0.05; and group III = 24.8 ± 4.7 minutes and group II = 8.8 ± 1.3 minutes, p < 0.05, respectively). All static and dynamic parameters and biomarkers of tissue oxygenation were affected by hemorrhagic shock and nearly all parameters were restored after resuscitation in both groups.
Conclusion: In the proposed model of hemorrhagic shock, resuscitation to the established endpoints was achieved within a smaller amount of time and with less volume when guided by PPV than when guided by pulmonary artery catheter-derived RVEDVI.
From the LIM08-Anesthesia (M.A.d.O., D.A.O., J.N.M., V.F.L.), Faculdade de Medicina da Universidade de São Paulo, Laboratory of Medical Investigation LIM/08; Department of Surgery (D.T.F.), Faculdade de Medicina Veterinária e Zootecnia da Universidade de São Paulo; and Department of Anesthesia and Surgical Intensive Care (J.O.C.A.), Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
Submitted for publication January 26, 2009.
Accepted for publication May 21, 2009.
Supported by grant 05/59470-0 from FAPESP and grant FMUSP/LIM-08 from Laboratory of Medical Investigation.
Presented, in part, at the 28th International Symposium on Intensive Care and Emergency Medicine, 2008.
Address for reprints: José Otávio Costa Auler, Jr., MD, PhD, Heart Institute (Incor), Hospital das Clınicas, Faculdade de Medicina, Universidade de São Paulo, Av. Dr. Enéas de Carvalho Aguiar 44, CEP 05403-000 São Paulo, Brazil; email: firstname.lastname@example.org.