Friday, February 22, 2013

Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation


Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation
Winkler BE, et al
Resuscitation, 2013

This was a randomized trial performed to evaluate the effectiveness of in-water resuscitation using different airway adjuncts.  This study has many weaknesses, but overall it is always exciting to see randomized trials being conducted within the open water lifesaving community.  Here is a synopsis of the study and its findings:

  • Study design
    • 19 lifeguards participated
    • Each performed 4 rescues in randomized order
      • No ventilations
      • Ventilation with mouth-to-mouth
      • Ventilation with bag valve mask
      • Ventilation with laryngeal tube (supraglottic device)
    • Each rescue was 100 meters
      • Manikin with measurement capabilities used
      • Ventilation performed every 10 seconds
  •  Measurements
    •  Rescue Time: from time of obtaining manikin to crossing finish line
    • Number of manikin submersions
    • Tidal volume and minute volume
    • Aspirated lung fluid in manikin
    • Subjective difficulty per rescuer
  • Results
    • Rescue times longer when ventilations performed
    • More submersions occurred when ventilations performed
    • Increased aspiration with mouth-to-mouth and bag-valve mask
    • Highest tidal volumes with laryngeal mask
      • Lowest with bag-valve
      • Laryngeal mask had stable tidal volumes
      • Adequate minute ventilations with mouth-to-mouth and bag-valve
 As stated before, what I like about this study was it was a fairly nicely designed and standardized look at in water resuscitation.  One weakness of the study is that it only deals with the time between contact with the victim and reaching land.  What it doesn't account for is the difficulty of reaching the patient with airway adjuncts (i.e. getting a bag valve mask out to the patient).  Another weakness was the use of manikins, which can't properly simulate a human's airway or evolving lung compliance due to aspiration, but this is likely the only study design possible.  The idea of using a supraglottic device is enticing since it gives adequate minute ventilations and would theoretically provide a barrier against aspiration, but I do question the feasibility of carrying a device and a bag valve mask to deliver ventilations during a rescue.

Source:
Winkler BE, et al. Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation–a randomized cross-over trial. Resuscitation; 2013.