Survey on the management of patients treated with therapeutic hypothermia post cardiac arrest in London hospitals

Introduction

The second UK national survey on therapeutic hypothermia (TH) post cardiac arrest demonstrated an impressive increase in its implementation across the UK (from 28% to 85.6%) [1]. Therapeutic hypothermia, however, induces numerous physiological and pathophysiological changes and therefore should be performed in a standardised and controlled manner in order to be safe and effective. We carried out a telephone survey to determine the current TH practice in London hospitals.

Methods

Thirty-two London intensive care units (ITUs) were contacted by telephone. The data were analysed using Excel spreadsheets.

Results

Of the 32 ITUs contacted, 30 (93.7%) had been using therapeutic hypothermia following cardiac arrest. Fifteen (50%) of them were teaching hospitals and the remaining 15 (50%) were district general hospitals. Twenty-two (73.3%) hospitals had a protocol in place. External cooling was the preferred method used by 28 (93.3%) hospitals. The target temperature varied from 32 to 35°C with two (6.7%) ITUs targeting a temperature of 32°C, 11 (36.7%) of 33°C, six (20%) of 34°C, one (10%) of 32 to 33°C, seven (23.4%) of 32 to 34°C and one (10%) of 34 to 35°C. The time of cooling varied between 12 and 48 hours. The cooling period was measured from initiation of cooling by 22 (73.3%) ITUs and from achievement of target temperature by six (20%) ITUs. Two responders were not sure how it was measured. Twenty-five (83.3%) units measured core temperature during the cooling. Passive rewarming was used by 20 (66.6%) responders. Twenty-four (80%) units maintain normothermia post therapeutic hypothermia. From additional aspects of the management of the induced hypothermia, 20 (66.6%) ITUs adjusted drug doses while starting TH, 15 (50%) monitored the depth of sedation, and 17 (56.6%) regularly checked train of four in paralyzed patients. Shivering was treated with sedation and paralysis by 25 (83.3%) of responders. Pregnancy status of all women younger than 50 years old was checked by 10 (33.3%) units. Fifteen (50%) units do not audit the practice regularly.

Conclusion

There are significant variations in practice between London hospitals which probably reflect the ongoing debate on the optimal management of patients treated with TH. Of note is that 50% of surveyed hospitals do not audit the current practice regularly which may have an impact on the quality and effectiveness of therapeutic cooling.