Matt Harmon

137 Chapter seven Introduction Targeted temperature management (TTM) is the main treatment modality for survivors of a cardiac arrest. 1 Large scale studies on mechanical ventilation practice after cardiac arrest and during TTM are scant. Ventilation strategies such as low tidal volume ventilation can improve outcome in patients with acute lung injury 2 and possibly also in patients without lung injury. 3,4 However implementation of lung protective ventilation strategies is difficult. 5,6 Recently, observational studies examined ventilation practices in ARDS 7 , and non-ARDS 8 , but these studies did not focus on cardiac arrest. Following the multi-center randomized target temperature management after cardiac arrest trial(TTM-trial) 9 , the recommendation to control temperature between 32°C and 36°C 10 yielded variation in practice of TTM management. 11 The effect TTM on mechanical ventilation settings is largely unknown. In a retrospective study in cardiac arrest patients, application of 33°C was associated with improved gas exchange. 12 Studying mechanical ventilation practices in patients following cardiac arrest may lead to optimization of ventilation during TTM and may ultimately improve outcome of these patients. The TTM trial provides a unique opportunity to study mechanical ventilation practices in cardiac arrest and to study the effect of temperature on parameters of mechanical ventilation. Therefore, the aims of this study were the following:1) to describe practice of mechanical ventilation and its independent relation with outcome.2) to determine effects of different target temperatures on mechanical ventilation parameters. We hypothesized that TTM at 33°C would lower ventilation settings needed for a minute volume ventilation. Methods Patients This study is a retrospective substudy of the multi-centre, randomized, parallel- group, assessor-blinded TTM-trial. The TTM-trial included adult (≥18 years) unconscious patients (Glasgow Coma Scale <8) resuscitated from cardiac arrest of a presumed cardiac cause with return of spontaneous circulation during at least 20 minutes. Following informed consent according to the regulations as approved by local IRB, patients were included at 36 centres in Europe and Australia. Further details on the exclusion criteria, trial protocol and main results were published previously. 9