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Abstract
A 37 year old man was found in his garden cold with no signs of life. Pupils were fixed and dilated. Electrocardiography showed asystole initially. The paramedic crew started cardiopulmonary resuscitation and transferred him to the accident and emergency department. His temperature was 17.0°C. Cardiopulmonary resuscitation was continued for three hours before rewarming using partial cardiopulmonary bypass. He eventually regained spontaneous cardiac output and made a full neurological recovery. Hypothermic patients with no evidence of life cannot be assumed to be dead as there is a chance of full recovery when fully warmed.
- hypothermia
- circulatory arrest
- resuscitation
- cardiopulmonary bypass
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The chance discovery of a hypothermic patient with no signs of life poses the question whether the patient got cold after death or is just cold but potentially salvageable. The decision taken can lead to either unnecessary prolonged and expensive resuscitation or loss of a life with potential to a full recovery. This is especially difficult when the ambient temperature is not near freezing. The cooling process is much slower with greater risk of neurological damage. We report a case of profound hypothermia secondary to accidental exposure successfully resuscitated with femoro-femoral partial bypass.
Late one evening in March at 2100 hours, a 37 year old man was found in his garden cold and unresponsive with no signs of life. The ambient temperature was 6°C (www.weatheronline.co.uk). The paramedic crew arrived at 2106 hours. The patient’s tympanic temperature was 17.0°C and electrocardiography showed asystole. The patient was intubated, ventilated, and external cardiac massage was started. He was given 1 mg of adrenaline (epinephrine) and developed pulseless electrical activity, which degenerated into ventricular fibrillation five minutes later. Two 200 J cardioversions had no effect.
In the accident and emergency department the patient was recognised as one with a history of schizophrenia, substance misuse, and previous admissions with overdose and alcohol intoxication. Further cardioversion with 360 J was unsuccessful. Pupils were fixed and dilated. Arterial blood gases showed pH of 6.9, Po2 of 4.7 and Pco2 of 9.9.
The prevailing feeling at the time was that he had been dead for some time before being discovered, but it was not possible to rule out potential recovery. External cardiac massage was continued and he was transferred to the operating theatre for rewarming on cardiopulmonary bypass.
The patient was anaesthetised and heparinised (3 mg/kg). The right femoral artery and vein were cannulated using a 17 French gauge arterial cannula and a 21 French gauge venous cannula (Medtronic Cardiac Surgical, Grand Rapids, MI, USA). Partial bypass with flow rates of between 2.2–2.8 l/min and mean perfusion pressure of 54–60 mm Hg was achieved. Full bypass with sternotomy was felt to be excessive.
With the nasopharyngeal temperature at 30°C, cardioversion with 200 J resulted in sinus rhythm for a few seconds before reverting to ventricular fibrillation. Eight further attempts with up to 360 J were also unsuccessful despite administration of amiodarone as per the Advanced Life Support protocol, intravenous lignocaine (lidocaine), and intravenous bretylium. After having been on bypass for an hour his nasopharyngeal temperature was 37°C. The heart regained sinus rhythm spontaneously and started ejecting achieving mean blood pressure of 80–100 mm Hg. He was maintained on partial bypass for another hour until his peripheries had warmed up before weaning off cardiopulmonary bypass on low dose adrenaline infusion.
The initial recovery was marred by adult respiratory distress syndrome. He was extubated a week later and was treated for alcohol withdrawal syndrome. He discharged himself against medical advice after another week.
COMMENT
Accidental hypothermia from immersion or exposure is a well recognised cause of cardiorespiratory arrest in regions with icy winters. Resuscitation with cardiopulmonary bypass with full recovery is possible but mortality remains high at 53% to 80%.1,2 In Hauty’s report, no patients with abscence of signs of life initially survived.2 The two survivors had core temperatures of 22.0°C and 23.4°C with some consciousness when discovered. In such cases immediate resuscitation ensures that organ perfusion, especially to the brain, is maintained.
Only two cases of hypothermia treated successfully with cardiopulmonary bypass have been reported from the United Kingdom.3,4 Both were responsive to stimuli initially with subsequent cardiorespiratory arrest. Rewarming was with extracorporeal circulation. The first patient made a full recovery and the second died of a cerebrovascular accident 48 hours after admission.
Our patient had no signs of life on discovery. The ambient temperature was far from freezing. It would have taken him longer to cool to 17°C. He could have been severely brain damaged if revived. We had no toxicological record but he could have been under the influence of alcohol or drugs that increased the cooling process. We were faced with a patient who could have been dead from intracranial catastrophe, fatal overdose, or asphyxiation. The Po2 was 4.7 with severe acidosis. Altogether he had five poor prognostic indicators.2 The decision to proceed to rewarm him was based on the adage that “Not dead until warm and dead” and the fact that with resuscitation the heart showed pulseless electrical activity followed by ventricular fibrillation rather than persistent asystole. The patient’s apparent full recovery lends support to the rationale.
We are aware that this patient may be an exception. Many patients discovered cold with no signs of life are presumed dead. In a small number of patients, the decision to proceed to resource intensive rewarming with cardiopulmonary bypass is probably worth taking if there is evidence of cardiac electrical activity. Partial femoro-femoral bypass is preferred in such circumstances.
Contributors
Chung Ko did the literature review and wrote the paper. Joseph Alex helped with the literature review and contributed to the paper. Stephen Jeffries helped with the perfusion related aspect of the paper. Jitendra Parmar discussed the core idea, revised the drafts and will act as guarantor for the paper.