title: Inhaled isoflurane sedation during therapeutic hypothermia after cardiac arrest: a case series.
abstract: OBJECTIVE
  Therapeutic hypothermia in the ICU requires mechanical ventilation and sedation. Hypothermia reduces the metabolism of commonly used IV sedatives. The use of long-acting sedative agents may confound neurologic assessment. Volatile anesthetics have been reported to provide protection against ischemia-reperfusion injury and have been safely used in the ICU to provide sedation in trials with shorter wake-up times. There are no clinical studies in this setting. We describe a case series and discuss potential benefits.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Ten-bed ICU, university hospital.
  
  
  METHODS
  Twelve patients resuscitated from cardiac arrest with Glasgow Coma Scale score less than or equal to 4.
  
  
  METHODS
  Isoflurane sedation with the AnaConDa during 24 hours therapeutic hypothermia, until rewarming.
  
  
  RESULTS
  Data were extracted from the computerized ICU chart/monitors, hospital and prehospital charts, and the national death index. Patients were 49-76 years old. Median return of spontaneous circulation was 14 minutes. Glasgow Coma Scale scores were assessed within 24 hours from reaching normal body temperature and compared with outcomes at 6 months: six patients had poor Glasgow Coma Scale scores (< 8) that remained low and all died before 6-month follow-up, whereas another six patients had high scores (> 8) and survived to 6 months with good Cerebral Performance Category. In the ICU, four of the survivors were directly extubated after rewarming while two were once more sedated due to pneumonia requiring invasive ventilator therapy. All patients required norepinephrine to maintain adequate mean arterial pressure. Isoflurane sedation was changed to midazolam in two nonsurviving patients because of hemodynamic instability, which persisted despite the change.
  
  
  CONCLUSIONS
  Sedation with volatile anesthetics during therapeutic hypothermia may be a feasible short-acting option with potential postconditioning effects protecting vital organs from ischemia-reperfusion injury. Its measurability and insignificant drug accumulation could facilitate early neurologic assessment. Prospective clinical trials are warranted.
authors.affiliation: 1Institution of Molecular Medicine and Surgery, Section of Cardiothoracic Surgery and Anesthesiology, Karolinska Institutet, Stockholm, Sweden. 2Institution of Physiology and Pharmacology, Section of Anesthesiology and Intensive Care Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jan
authors.initials: J
authors.lastname: Hellström
authors.forename: Anders
authors.initials: A
authors.lastname: Öwall
authors.forename: Claes-Roland
authors.initials: CR
authors.lastname: Martling
authors.forename: Peter V
authors.initials: PV
authors.lastname: Sackey
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D054810:Deep Sedation / Q000379:methods*; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced; D007530:Isoflurane / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D007530:Isoflurane