engleski

Comparison between arterial, muscle and inactive tissue oxygen content during repetitious breath-hold in apnea divers

Decrease of oxygen content during apnea diving is detected with variety of methods. Precision and time course of desaturation measured with near infrared method in divers is not well known. The aim of present study was to compare level of arterial, skeletal muscle and inactive tissue oxygen content during series of breath-hold apneas. Five maximal apneas, with two-minute interval between each breath-hold, was executed by six apnea divers. Face of the subjects was immersed in cold water (10-12 °C). We continuously monitored arterial blood pressure, heart rate, and respiratory musculature movements. Probe of the pulse oxymeter was placed on the middle finger of the dominant hand for monitoring arterial oxygen saturation. Skeletal muscle oxygen saturation of the calf skeletal muscle was measured with near infrared spectroscopy method using a 25 mm probe. Partial pressure of oxygen in inactive tissue was monitored by placing transcutaneous probe over the suprascapular muscle. All parameters were continuously recorded with data acquisition system and stored on personal computer for later analysis. In response to performance of breath-holds, arterial oxygen saturation decreased from baseline value of 98.3± ; 0.3% to 86.5± ; 2.3% ; muscle saturation decreased to 59.8± ; 8.5% (from 85.4± ; 3.3%) ; and inactive tissue partial pressure of oxygen decreased from 74.9± ; 3.0mmHg at baseline to 43.2± ; 4.7mmHg. Maximal nadir in oxygen content occurred 26.8, 13.5 and 17.2 seconds after termination of apnea for arterial oxygen saturation, muscle oxygen saturation, and partial pressure of oxygen in inactive tissue, respectively. In conclusion we suggest that near infrared spectroscopy represents a new and rapid method for detection of desaturation in skeletal muscle of the divers.

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