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

Abstract

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. 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. 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. 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.