Sleep Apnea

While other variables such as changing Vo2 and cardiac output could have affected dSaCVdt, their effect should have been mainly through changing Sv02. Thus, lack of these data does not detract from the present study. We attempted to measure cardiac output at the beginning and end of apneas in several of the subjects. Because of […]

Thus, by virtue of volume alone, central venous blood oxygen level should play a major role in determining dSaCydt. Other factors which affect dSaCydt aside from thoracic gas volume should do so through their effect upon SvC>2. For example, increased Vo2 would cause greater tissue oxygen extraction, thereby lowering Sv02, causing more rapid depletion of […]

These data indicate that variability of dSaCVdt during OSA is negatively correlated to preapneic Sv02-This relationship has previously been demonstrated during the rigid stiidy conditions of an obstructive breath hold in supine, spontaneously breathing baboons. It has not been demonstrated during sleep in humans where varying apnea duration and recovery periods between apneas produce wide […]

Accuracy of the Biox IIA ear oximeter for this laboratory has been calculated for the steady state by comparing the oximeter readings from 82 samples (40 patients) of arterial blood analyzed by hemoximeter (OSM II, Radiometer, Copenhagen). The correlation coefficient for steady state samples was 0.933. Correlation between ear oximeter and hemoximeter under non-steady state […]

Methods Eight obese male subjects with previously established diagnoses of OSA were recruited from the Houston Veterans Administration Medical Center chest clinics. All subjects signed informed consents. There was a wide range of values for arterial blood gases and resting SW* levels (Tables 1 and 2) due to the presence of concomitant lung disease in […]

Rapid falls in oxyhemoglobin saturation (SaO^ occur in patients with obstructive sleep apnea (OSA) and may lead to profound hypoxemia. The depth of each desaturation episode is dependent upon the duration of the apnea and the rate of fall of Sa02 (dSaCVdt). Factors determining the duration of an apnea are probably related to neural reflexes, […]