Optimization of induction of mild therapeutic hypothermia with cold saline infusion: A laboratory experiment.

Jure Fluher,Andrej Markota,Andreja Sinkovič,Andraž Stožer

doi:10.17305/bjbms.2015.565

Abstract

Cold fluid infusions can be used to induce mild therapeutic hypothermia after cardiac arrest. Fluid temperature higher than 4°C can increase the volume of fluid needed, prolong the induction phase of hypothermia and thus contribute to complications. We performed a laboratory experiment with two objectives. The first objective was to analyze the effect of wrapping fluid bags in ice packs on the increase of fluid temperature with time in bags exposed to ambient conditions. The second objective was to quantify the effect of insulating venous tubing and adjusting flow rate on fluid temperature increase from bag to the level of an intravenous cannula during a simulated infusion. The temperature of fluid in bags wrapped in ice packs was significantly lower compared to controls at all time points during the 120 minutes observation. The temperature increase from the bag to the level of intravenous cannula was significantly lower for insulated tubing at all infusion rates (median temperature differences between bag and intravenous cannula were: 8.9, 4.8, 4.0, and 3.1°C, for non-insulated and 5.9, 3.05, 1.1, and 0.3°C, for insulated tubing, at infusion rates 10, 30, 60, and 100 mL/minute, respectively). The results from this study could potentially be used to decrease the volume of fluid infused when inducing mild hypothermia with an infusion of cold fluids.

Highlights

Targeted temperature management is an important part of the post-resuscitation care of comatose survivors of cardiac arrest
For the analysis of the warming rate of fluid in the bag, the temperature was measured for 120 minutes in three fluid bags wrapped in ice packs and three non-wrapped control bags (Figure 1)
For fluid bags wrapped in ice packs, during the first 20 minutes, the fluid temperature decreased (Figure 1), and only from that time point on, the fluid gradually warmed

Summary

Introduction

Targeted temperature management is an important part of the post-resuscitation care of comatose survivors of cardiac arrest. Mild induced hypothermia (MIH) at a temperature 32-34°C after cardiac arrest seems to increase the likelihood of neurologically intact survival [1,2,3]. Induction of MIH by infusion of cold fluid is simple, cheap, does not require special equipment, and can be performed in a pre-hospital environment, emergency department, or an intensive care unit setting [4,5]. Patients who received greater volumes of cold fluids in the induction phase of MIH required higher levels of positive end-expiratory pressure, a higher fraction of inspired oxygen and more diuretics due to pulmonary edema. It seems reasonable to try to achieve the target temperature with the least possible volume of fluid [6].

Methods

Results

Discussion

Conclusion