Blood pressure-targeted stepwise resuscitation of hemorrhagic shock in a swine model

Abstract

Background: Prolonged hemorrhagic shock and subsequent resuscitation frequently results in hemodynamic compromise. This study was designed to investigate the hemodynamic effect of the stepwise increase of blood pressure during initial resuscitation.

Materials and methods: Fifteen anesthetized male pigs (35 ± 5 kg) were used. Hemorrhagic shock was induced by losing 40% of estimated blood volume over 40 min and 10% of estimated blood volume over 20 min through the femoral artery and was maintained at a mean arterial pressure (MAP) of 30 ± 3 mm Hg for 2.5 h. The resuscitation of the rapid resuscitation (RR) group was targeted to reach MAP of 70 ± 5 mm Hg immediately by transfusion of shed blood via the femoral artery. The resuscitation of the pressure-targeted stepwise resuscitation (PSR) group was targeted to increase MAP by 10 mm Hg every 10 min up to 70 mm Hg, and then, the MAP was maintained at 70 ± 5 mm Hg until transfusion of the entire shed blood.

Results: During the initial resuscitation period of 30 min, the heart rate was significantly lower in the RR group than in the PSR group (P < 0.05), and mixed venous oxygen saturation was significantly higher in the RR group than in the PSR group during the 30 min of initial resuscitation (P < 0.05). After 2 h of resuscitation, cardiac output and stroke volume were significantly higher in the PSR group than in the RR group (P < 0.05), and the systemic vascular resistance was significantly lower in the PSR group than in the RR group (P < 0.05).

Conclusions: A stepwise increase of blood pressure compared with rapid normalization improves hemodynamic parameters in the swine hemorrhagic shock model.

Keywords: Hemorrhagic shock; Myocardial dysfunction; Resuscitation.