[Emergency respirator therapy in intermediate altitude with the Ambu Matic]

Portable emergency ventilators are commonly used in a pre-hospital setting in the transport of critically ill patients also in hypobaric environments. The aim of our trial was to evaluate the influence of moderate altitude at 2700 m compared to 171 m altitude on minute ventilation and blood gas analysis in healthy volunteers during mechanical ventilation with the Ambu Matic ventilator. At 2700 m altitude, the delivered minute volume increased by 13.8%. paCO2 decreased by 9.2% (p < 0.01 for all reported changes). No statistical change in paO2 at 2700 m altitude was observed. These changes are of sufficient magnitude and importance to require monitoring of minute volume to prevent volutrauma or barotrauma.