Elsevier

Resuscitation

Volume 39, Issues 1–2, November 1998, Pages 61-66
Resuscitation

Preliminary clinical outcome study of mild resuscitative hypothermia after out-of-hospital cardiopulmonary arrest

https://doi.org/10.1016/S0300-9572(98)00118-XGet rights and content

Abstract

The effects of mild hypothermia (MH) were investigated. From 1995 to 1996, 28 adult patients with out-of-hospital cardiopulmonary arrest (CPA) had return of spontaneous circulation and survived for more than two days. Thirteen patients were in the MH group. In the MH group, core temperature was maintained between 33 and 34°C for 48 h, and then re-warmed to a temperature of 37°C, at a rate of no greater than 1°C per day. Fifteen patients, admitted before the MH protocol was instituted, were in the control group. Despite the fact that the number of witnessed arrests in the control group were greater than in the MH group, there were both more survivors (7/13 vs. 5/15) and more fully recovered patients (3/13 vs. 1/15) in the MH vs Control groups. Eleven of 13 MH patients, as compared to 6/15 controls developed pneumonia. Our study, although preliminary, suggests that MH might confer improved outcome, as has been shown in animal models, after CPA. This treatment is associated with an increase in pneumonic complications.

Introduction

Cerebral protection and preservation via induced hypothermia prior to hypoperfusion has been shown to prevent postischemic brain damage following total circulatory arrest in the setting of cardiothoracic or neurologic surgery 1, 2, 3, 4, 5, 6. Therapeutic hypothermia is divided into four categories: mild (33–36°C) moderate (27–33°C), deep (16–27°C), and profound (4–16°C) 7, 8, 9. There are outcome studies in animals, which have shown that resuscitative (post arrest) mild hypothermia (MH) mitigates 7, 8, 9and even prevents [10]postischemic brain damage after normothermic cardiopulmonary arrest of 10–12 min. MH is thought to protect against secondary brain damage induced by cardiopulmonary arrest by inhibiting calcium loading, glutamate release, free–radical induced lipid peroxidation of membranes, and hypermetabolism 7, 11. Moderate hypothermia after cardiac arrest appears beneficial for cerebral, but risky for cardiac, recovery [12]. Mild hypothermia during cardiac arrest in dogs was found to be associated with better cerebral outcome [13]. In humans, there have been a few reports that suggest a beneficial effect of MH after CPA 1, 14, 15, 16.

Recently we developed a new protocol of MH for patients after out-of-hospital CPA and applied it in a pilot study comprised of 13 patients. The objective of this preliminary study was to determine the feasibility and usefulness of MH by evaluating background survival and neurological outcome of these patients compared to a historical group of normothermic controls.

Section snippets

Materials and methods

The National Defense Medical College is an 800-bed hospital in suburban Tokyo, with a catchment population of approximately 800 000. There are approximately 3000 CPA in this area every year, of which approximately 150 are treated in our center. In the Japanese emergency medical service (EMS) system, emergency medical technicians (EMTs) are allowed only to perform basic life support. In January 1995, the new Japanese EMS system enabled paramedics to perform certain advanced life support skills,

Results

In 11 subjects, core temperature was measured via bladder catheter; in these individuals the cooling blanket was automatically regulated by the bladder temperature. The remaining two used pulmonary artery temperature, with the cooling blanket regulated manually. In three cases both the bladder and the pulmonary artery temperatures were recorded. The differences between the two values were within 0.5°C (r2=0.861, p<0.01) and correlation was excellent.

Surface cooling was initiated within 78±28

Discussion

We have shown that fully recovered survivors tended to be more frequently observed in the MH group, as compared to the control group, patients. However, the results did not achieve statistical significant, thus limiting the conclusion we can draw. The reasons for our inability to achieve significance include the small number of patients in each group. Additionally, there were few witnessed collapses in the MH group as compared to controls. Usually the witnessed collapse leads to a more

Conclusion

The smaller number of the witnessed arrests in the MH group suggests more severe insults than in the control group. However, there was a trend toward better outcome in the MH group. MH might be potentially beneficial in patients after CPA. Accordingly, further human study is warranted. This study should address the safety of interventional hypothermia with definitive cooling protocol and overall outcome. A prospective randomized control trial has been instituted in our hospital and a

Acknowledgements

The authors thank Dr Peter Safar, Professor at the University of Pittsburgh, and Dr A. Joseph Layon, Professor of Anesthesiology, Surgery, and Medicine at the University of Florida College of Medicine for their helpful comments.

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