Sleep
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Uvulopalatopharyngoplasty (UPPP) is frequently employed in the treatment of obstructive sleep apnea (OSA). Despite anecdotal reports of early post-UPPP deaths and the recommendation by some authors to perform a prophylactic tracheotomy for selected patients at the time of UPPP, there has been no systematic examination of breathing during sleep in the early post-UPPP period. In order to evaluate the early postoperative risk and the need for prophylactic tracheotomy in UPPP patients, we conducted polysomnograms (PSGs) on eight obese OSA patients on the second post-UPPP night and on another obese OSA patient on the fifth night after surgery. ⋯ In lieu of this, these individuals should be carefully monitored following surgery. In addition, patients with severe OSA and/or moderate-to-severe nocturnal hemoglobin oxygen desaturation should be considered for early postoperative PSGs as should those individuals who are more hypoxemic while awake following surgery. Patients who require supplemental oxygen postoperatively should also be studied to ensure adequate oxygenation and to monitor for acute, oxygen-related prolongation of apnea.
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Six men and three women, asymptomatic light snorers ranging in age from 25-34 years, were studied during sleep to determine the prevalence of snoring in the different sleep stages, the associated changes in oxygen saturation (SaO2), heart rate (HR), and breathing frequency (f), and the associated breathing arrhythmias. Snoring was defined as a 1-minute epoch with more than 80% of the breaths associated with snores. Most of the snoring epochs as well as the apneas and hypopneas occurred during stage 2, mainly because it is the most prolonged sleep stage. ⋯ Snoring caused no change in the mean SaO2, mean HR, or f, as compared with nonsnoring periods in the same sleep stage. Continuous snoring in normal subjects can occur without significant O2 desaturation or breathing arrhythmia. Continuous snoring and breathing arrhythmia tended to occur together in a given subject but were unrelated in time, suggesting a different pathogenesis.
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Comparative Study
Dynamic in vivo response characteristics of three oximeters: Hewlett-Packard 47201A, Biox III, and Nellcor N-100.
Pulse oximeters (Biox III, Nellcor N-100) and a transmittance oximeter [Hewlett-Packard 47201A (HP)] were compared for SaO2 measurement and responsiveness during dynamic changes in arterial oxygen saturation and heart rate. Five sleep apnea syndrome patients were studied because they had large oscillations in SaO2 and heart rate in sleep. During sleep, each patient exhibited a series of rapid (18.0 +/- 8.3 s, mean +/- SD) oscillations in oxygen saturation (92.1 +/- 2.6% to 74.2 +/- 7.7%). ⋯ Pulse oximeter response delay was highly correlated with heart rate. Pulse oximeter SaO2 measurement and response characteristics varied considerably with sensor type (disposable, reusable) and sensor location (ear, nose, and digit). One must be aware of these differences in clinical and research application.
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Oxygen desaturation in chronic obstructive pulmonary disease (COPD) occurs during sleep and is most marked in REM sleep. REM is not a homogeneous state, consisting of phasic REM (PREM) (REMs, myoclonic twitches) and tonic REM (TREM) (muscle atonia, desynchronized electroencephalogram). In normals, onset of PREM produces transient changes in breathing pattern with a decrease in respiratory amplitude and an increase in frequency, which produce reductions in oxygen saturation (SaO2). ⋯ Mean awake SaO2 was 89.7 +/- 0.8%. We conclude that in COPD the transition from TREM to PREM is associated with breathing pattern changes and oxygen desaturation. Differences in breathing pattern with PREM onset may be related to different effects of PREM processes on respiratory neurons and diaphragm motor neurons.