Mechanical ventilation and resuscitation under water: Exploring one of the last undiscovered environments--A pilot study.

Introduction: Airway management, mechanical ventilation and resuscitation can be performed almost everywhere--even in space--but not under water. The present study assessed the technical feasibility of resuscitation under water in a manikin model.

Methods: Tracheal intubation was assessed in a hyperbaric chamber filled with water at 20 m of depth using the Pentax AWS S100 video laryngoscope, the Fastrach™ intubating laryngeal mask and the Clarus optical stylet with guidance by a laryngeal mask airway (LMA) and without guidance. A closed suction system was used to remove water from the airways. A test lung was ventilated to a maximum depth of 50 m with a modified Oxylator(®) EMX resuscitator with its expiratory port connected either to a demand valve or a diving regulator. Automated chest compressions were performed to a maximum depth of 50 m using the air-driven LUCAS™ 1.

Results: The mean cumulative time span for airway management until the activation of the ventilator was 36 s for the Fastrach™, 57 s for the Pentax AWS S100, 53s for the LMA-guided stylet and 43 s for the stylet without LMA guidance. Complete suctioning of the water from the airways was not possible with the suction system used. The Oxylator(®) connected to the demand valve ventilated at 50 m depth with a mean ventilation rate of 6.5 min(-1) vs. 14.7 min(-1) and minute volume of 4.5 l min(-1) vs. 7.6 l min(-1) compared to the surface. The rate of chest compression at 50 m was 228 min(-1) vs. 106 min(-1) compared to surface. The depth of compressions decreased with increasing depth.

Conclusion: Airway management under water appears to be feasible in this manikin model. The suction system requires further modification. Mechanical ventilation at depth is possible but modifications of the Oxylator(®) are required to stabilize ventilation rate and administered minute volumes. The LUCAS™ 1 cannot be recommended at major depth.