Performance of closed-loop resuscitation in a pig model of haemorrhagic shock with fluid alone or in combination with norepinephrine, a pilot study.

Abstract

We evaluated the performance of a new device to control the administration of fluid alone or co-administration of fluid and norepinephrine in a pig model of haemorrhagic shock in two sets of experiments. In the first one, resuscitation was guided using continuous arterial pressure measurements (three groups: resuscitation with fluid by a physician, CL resuscitation with fluid, and CL resuscitation with fluid and norepinephrine). In the second one, resuscitation was guided using discontinuous arterial pressure measurements (three groups: CL resuscitation with fluid alone, CL resuscitation with fluid and moderate dose norepinephrine, and CL resuscitation with fluid and a high dose of norepinephrine). Pigs were resuscitated for 1h. In the first set of experiments, proportion of time spent in the target area of 78-88mmHg of systolic arterial pressure was not statistically different between the three groups: manual, 71.2% (39.1-80.1); CL with fluid, 87.8% (68.3-97.4); and CL with fluid and norepinephrine, 78.1% (59.2-83.6), p = 0.151. In the second set of experiments, performance of CL resuscitation with fluid or with combination of fluid and high or moderate dose of norepinephrine was not significantly different (p = 0.543 for time in target). Pigs resuscitated with norepinephrine required less fluid and had less haemodilution than pigs resuscitated with fluid alone. Performance of CL resuscitation using continuous arterial pressure measurement was not significantly different than optimised manual treatment by a dedicated physician. Performance of CL resuscitation was reduced with discontinuous arterial pressure measurements in comparison with continuous arterial pressure measurements.