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Use of an oesophageal heat transfer device in therapeutic hypothermia

      Sir,
      A number of methods exist for temperature management after cardiac arrest, all of which have limitations, namely, excessive fluid loading with cold saline infusion, decreased efficacy in external cooling or rewarming methods and invasiveness required for intravascular devices.
      • Gillies M.A.
      • Pratt R.
      • Whiteley C.
      • Borg J.
      • Beale R.J.
      • Tibby S.M.
      Therapeutic hypothermia after cardiac arrest: a retrospective comparison of surface and endovascular cooling techniques.
      Recently, a new esophageal heat transfer device has become available, offering potential advantages over current methods.
      • Kulstad E.
      • Metzger A.K.
      • Courtney D.M.
      • et al.
      Induction, maintenance, and reversal of therapeutic hypothermia with an esophageal heat transfer device.
      We report here the first clinical experience during therapeutic hypothermia in Europe with this device.
      Our first patient was a 56-year-old male admitted after out-of-hospital cardiac arrest. First recorded temperature in bladder was 35.5 °C and he received 1000 ml of iced saline after admission (2000 ml in all). The oesophageal heat transfer device (Esophageal Cooling Device, Advanced Cooling Therapy, Chicago, Illinois, USA) was inserted when temperature in the bladder was 34.8 °C. In the following 30 min temperature decreased to 33 °C. The 24 h maintenance phase and gradual rewarming in 12 h were achieved using the device alone (Fig. 1).
      Figure thumbnail gr1
      Fig. 1Temperature versus time graph for both included patients. Legend: ECD = oesophageal heat transfer device.
      Our second patient was a 51-year-old female, also admitted after out-of hospital cardiac arrest. Cold fluid infusion was terminated after 2000 ml because of pulmonary edema, requiring high levels of positive end-expiratory pressure (18 cmH2O) and 100% fraction of inspired oxygen. The device was inserted 15 min after admission when bladder temperature was 35.8 °C. 45 min later her temperature was 33.6 °C and was maintained around 33 °C for the following 24 h. Normothermia was achieved in 8 h (Fig. 1). After admission no other method was used for temperature management.
      Both patients developed sinus bradycardia during the maintenance phase. It resolved spontaneously and was attributed to hypothermia. Insertion of device was possible in first attempt in both patients. There were no signs of oral cavity damage or of gastrointestinal bleeding, although formal oral cavity and pharynx examination by otorhinolaryngologist or oesophagogastroduodenoscopy were not performed. Enteral feeding via gastric lumen of esophageal heat transfer device followed by enteral feeding via nasogastric tube once the device was removed was possible without complications. Both patients required brain CT while device was in situ. The device was unobtrusive during transport and imaging.
      In both patients the device was inserted during the induction phase of therapeutic hypothermia and temperature reduction was initiated with cold saline infusion. It is likely that it contributed to a lower volume of cold saline needed to induce hypothermia and probably enabled us to achieve target temperature in second patient.
      • Kim F.
      • Nichol G.
      • Maynard C.
      • et al.
      Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial.
      During the maintenance phase temperature was kept between 32 and 33.9 °C without excessive fluctuations. We could prevent excessive temperature rise during rewarming.
      • Bro-Jeppesen J.
      • Hassager C.
      • Wanscher M.
      • et al.
      Post-hypothermia fever is associated with increased mortality after out-of-hospital cardiac arrest.
      This is comparable to intravascular devices and superior to most studies of surface devices.
      • Gillies M.A.
      • Pratt R.
      • Whiteley C.
      • Borg J.
      • Beale R.J.
      • Tibby S.M.
      Therapeutic hypothermia after cardiac arrest: a retrospective comparison of surface and endovascular cooling techniques.
      In addition, in case more diagnostic or therapeutic procedures are needed (e.g. echocardiography or defibrillation), external devices may need to be at least partially removed.
      The new oesophageal heat transfer device proved effective during therapeutic hypothermia in two adult survivors of cardiac arrest, suggesting a potentially useful new modality for temperature management. Further studies are needed to assess its role in temperature management in survivors of cardiac arrest and other patient populations.

      Conflict of interest statement

      Both oesophageal heat transfer devices were provided by the manufacturer (Advanced Cooling Therapy, Chicago, USA).

      References

        • Gillies M.A.
        • Pratt R.
        • Whiteley C.
        • Borg J.
        • Beale R.J.
        • Tibby S.M.
        Therapeutic hypothermia after cardiac arrest: a retrospective comparison of surface and endovascular cooling techniques.
        Resuscitation. 2010; 81: 1117-1122
        • Kulstad E.
        • Metzger A.K.
        • Courtney D.M.
        • et al.
        Induction, maintenance, and reversal of therapeutic hypothermia with an esophageal heat transfer device.
        Resuscitation. 2013; 84: 1619-1624
        • Kim F.
        • Nichol G.
        • Maynard C.
        • et al.
        Effect of prehospital induction of mild hypothermia on survival and neurological status among adults with cardiac arrest: a randomized clinical trial.
        JAMA. 2014; 311: 45-52
        • Bro-Jeppesen J.
        • Hassager C.
        • Wanscher M.
        • et al.
        Post-hypothermia fever is associated with increased mortality after out-of-hospital cardiac arrest.
        Resuscitation. 2013; 84: 1734-1740