Elsevier

Resuscitation

Volume 64, Issue 3, March 2005, Pages 347-351
Resuscitation

Cold simple intravenous infusions preceding special endovascular cooling for faster induction of mild hypothermia after cardiac arrest—a feasibility study

https://doi.org/10.1016/j.resuscitation.2004.09.002Get rights and content

Abstract

Objective:

Mild therapeutic hypothermia has shown to improve neurological outcome after cardiac arrest. Our study investigated the efficacy and safety of cold simple intravenous infusions for induction of hypothermia after cardiac arrest preceding further cooling and maintenance of hypothermia by specialised endovascular cooling.

Methods:

All patients admitted after cardiac arrest of presumed cardiac aetiology were screened. Patients enrolled received 2000 ml of ice-cold (4 °C) fluids via peripheral venous catheters. As soon as possible endovascular cooling was applied even if the cold infusions were not completed. The target temperature was defined as 33 ± 1 °C. All temperatures recorded were measured via bladder-temperature probes. The primary endpoint was the time from return of spontaneous circulation to reaching the target temperature. Secondary endpoints were changes in haemodynamic variables, oxygenation, haemoglobin, clotting variables and neurological outcome.

Results:

Out of 167 screened patients 26 (15%) were included. With a total amount of 24 ± 7 ml/kg cold fluid at 4 °C the temperature could be lowered from 35.6 ± 1.3 °C on admission to 33.8 ± 1.1 °C. The target temperature was reached 185 ± 119 min after return of spontaneous circulation, 135 ± 112 min after start of infusion, and 83 ± 85 min after start of endovascular cooling. Except for two patients showing radiographic signs of mild pulmonary edema no complications attributable to the infusions could be observed. Thirteen patients (50%) survived with favourable neurological outcome.

Conclusion:

Our results indicate that induction of mild hypothermia with infusion of cold fluids preceding endovascular cooling is safe and effective.

Introduction

Prolonged global ischaemia during cardiac arrest and insufficient reperfusion during the immediate post-resuscitation period leads to severe hypoxic brain injury [1]. Several therapeutic interventions have been assessed for preventing or diminishing hypoxic brain damage after cardiac arrest. Despite promising results from experimental data most strategies failed to show beneficial effects in human or animal outcome studies [2], [3], [4], [5]. Therapeutic hypothermia has been used in cardiac surgery and neurosurgery and it is well known that patients suffering from hypothermic cardiac arrest have a better chance of recovering with good neurological outcome [6]. In the past, animal data has suggested that induction of therapeutic hypothermia after or in cardiac arrest could prevent hypoxic brain damage [7], [8]. In 2002, two randomized controlled trials presented good evidence for the efficacy of therapeutic mild hypothermia after cardiac arrest in humans [9], [10]. On the basis of these trials the International Liaison Committee on Resuscitation (ILCOR) now recommends that comatose adult survivors of out-of-hospital cardiac arrests whose first recorded rhythm was ventricular fibrillation should be cooled for 12–24 h and that this intervention might also be beneficial for in-hospital arrests or other rhythms [11].

Many different cooling techniques have been assessed for efficacy and safety, both in animals and humans [7], [12], [13], [14]. As there is evidence that the time until therapeutic hypothermia is reached has an important impact on outcome [15], [16], a simple cooling method that could be applied even out-of-hospital by paramedics or emergency physicians immediately after a return of spontaneous circulation potentially would be beneficial. So far, one study by Bernard et al. [17] showed that rapid infusions of large amounts (30 ml/kg) of cold fluids after cardiac arrest can be administered safely in patients without clinical signs of pulmonary oedema and that those infusions led to a significant decrease in patient core temperature. Extending this approach, our current study investigated the efficacy and safety of cold infusions for induction of hypothermia after cardiac arrest preceding further cooling and maintenance of hypothermia by specialised endovascular cooling.

Section snippets

Methods

The study was performed in an emergency department of a tertiary care hospital. Between 1 June 2003 and 15 April 2004 all patients after successful resuscitation from cardiac arrest were screened for eligibility. Data from all patients were collected according to the international “Utstein”—style criteria [18]. The procedures were in accordance with the ethical standards of the responsible committee on human experimentation and with the Helsinki Declaration of 1964, as revised at the 52nd

Results

Over a period of 10.5 months, 26 patients (15%) were included out of 167 with cardiac arrest. Demographic and cardiac arrest data are given in Table 1. Causes of cardiac arrest other than cardiac were pulmonary (n = 1), near drowning (n = 1) and unknown in one patient.

Time from return of spontaneous circulation to admission was 38 (±23) min, time from return of spontaneous circulation to start of administration of cold infusions was 53 ± 29 min, infusions were started 14 ± 17 min after admission. In all

Discussion

The early induction of mild therapeutic hypothermia using rapid infusions of approximately 2 l of intravenous cold fluids at 4 °C immediately after admission to the emergency department preceding specialised endovascular cooling after cardiac arrest was feasible and safe. No harmful side effects were observed in patients given these amounts of cold fluids via peripheral intravenous lines shortly after restoration of spontaneous circulation.

Using a total amount of 24 ± 7 ml/kg body weight of Ringers’

Conclusions

Experimental data are indicating that therapeutic hypothermia can lead to better neuroprotection if applied soon after global ischemia. Therefore, earlier application of therapeutic hypothermia by simple methods, which could be used by medical professionals in the pre-hospital setting might offer a great potential for better neurological outcome. Techniques such as intravenous cold infusions preceding endovascular cooling could be used. To strengthen that assumption randomised controlled

References (25)

  • W. Behringer et al.

    Rapid hypothermic aortic flush can achieve survival without brain damage after 30 min cardiac arrest in dogs

    Anesthesiology

    (2000)
  • W. Behringer et al.

    Rapid induction of mild cerebral hypothermia by cold aortic flush achieves normal recovery in a dog outcome model with 20 min exsanguination cardiac arrest

    Acad Emerg Med

    (2000)
  • Cited by (151)

    • Hypothermia for Acute Spinal Cord Injury

      2021, Neurosurgery Clinics of North America
    • A Cooling Conundrum: Is Therapeutic Hypothermia Safe in the Immunosuppressed?

      2023, Therapeutic Hypothermia and Temperature Management
    View all citing articles on Scopus

    A Spanish and Portuguese translated version of the Abstract and Keywords of this article appears at doi: 10.1016/j.resuscitation.2004.09.002.

    View full text