There was a large disparity in readings outside the predicted range. After swimming in cold water, the Nellcor N-65 did not display any value in 7 volunteers, depicted as “7 no readings” on the ≤70% line (Fig. 1). All of the

other oxygen saturation values obtained with this pulse oximeter in cold water swimming were 100%. The other pulse oximeters also gave less than predicted oxygen saturations with cold water swimming: the Lifepak 20 between 64% and 78%; the PM-60 between 36% and 93%; the Nonin Onyx between 54% and 94%; the GE TuffSat between 80% and 90%; and the Nonin PalmSat between 80% and 93%. In this preliminary study, pulse oximetry did not reliably measure oxygen saturations in healthy individuals after brief submersion and after swimming in either warm or cold water. In relatively

warm swimming pool water, four pulse oximeters did not fail, but in outdoor Saracatinib chemical structure cold water SCH772984 solubility dmso all pulse oximeters failed. There was also considerable variability between different pulse oximeters. In actual drowning scenarios, with a lower water temperature, or prolonged time in the water, or a non-healthy victim, pulse oximetry measurements may be even more inaccurate. Software, intensity of the light source or fitting of the finger clips may be responsible for this. Oxygen is a key early treatment for the resuscitation of drowning victims.7 The detection of hypoxaemia and monitoring of oxygen therapy may however be difficult. The routine administration of 100% inspired oxygen is potentially harmful during resuscitation of drowning victims if hyperoxia occurs.7, 9 and 10 Over the last

few decades, professional and volunteer lifeguards and rescue boat crews have been increasingly equipped with oxygen delivery devices. Studies related to extremes in aquatic sports and diving physiology have used pulse oximetry successfully to obtain data on arterial oxygen saturation.15, 16, 17 and 18 These studies show that, when well prepared, Epothilone B (EPO906, Patupilone) pulse oximetry can be applied in the aquatic environment. Our study in more common drowning situations suggests that pulse oximeters should not be routinely used to measure oxygen saturation in this setting during initial resuscitation. Our study has several limitations. First of all, we did not measure the actual arterial oxygen saturation from an arterial blood sample using co-oximetry. We assumed any pulse oximetry reading of ≤94% was inaccurate as the oxygen saturation of our study participants was very likely to remain above 94%. Studies dealing with sports training and exercise in water confirm this.15 and 16 The technical and ethical issues involved to undertake blood sampling and measurement were beyond the scope of this preliminary study. Moreover, the aim of the present study was to explore whether a more complex study is needed. During the experiments, there was a large amount of variability between the pulse oximeters.