Crystalloid infusion rate during fluid resuscitation from acute haemorrhage

Abstract

Background: Information is lacking concerning optimal infusion rates of crystalloid during resuscitation from acute haemorrhage. In this study, a mathematical model was used to predict infusion volume of crystalloid needed to restore and maintain blood volume after acute haemorrhage. Methods: The scenario was a haemorrhage of 15 ml kg-1 over 30 min in a 70 kg man. A bolus of crystalloid was administered at a rate of 40, 60, 80, 100, or 120 ml kg-1 h-1 until blood volume was restored. Fluid infusion rate needed to maintain blood volume for a further 1 h was computed. Results: Blood volume was restored earlier at high bolus infusion rates compared with low bolus infusion rates (6 min at 120 ml kg-1 h-1 vs 63 min at 40 ml kg-1 h-1). Fluid infusion rates for blood volume maintenance approached 33 ml kg-1 h-1 irrespective of bolus infusion rates. The restoration fluid volume at 40 ml kg-1 h-1 was 2.9 litre, three times that at 80-120 ml kg-1 h-1. The maintenance fluid volume at 80-120 ml kg-1 h-1 was 2.9 litre, 0.6 litre more than that at 40 ml kg-1 h-1. During the blood volume maintenance, the interstitial volume increased to 3.8 litre above normal at 40 ml kg-1 h-1 and to 2.5 litre at 80-120 ml kg-1 h-1. Conclusions: Bolus crystalloid infusion exceeding 80 ml kg-1 h-1 may not increase effectiveness of fluid resuscitation. Crystalloid resuscitation for more than 2 h may be detrimental in view of an excessive net fluid retention. © The Board of Management and Trustees of the British Journal of Anaesthesia 2007. All rights reserved.