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S Gyulay

Publications and source records attributed to S Gyulay.

5 recordsLinked to original sources
PubMed1993

A comparison of clinical assessment and home oximetry in the diagnosis of obstructive sleep apnea.

In order to determine whether measurement of arterial oxygen saturation (SaO2) could identify patients with obstructive sleep apnea (OSA), 98 consecutive patients referred for assessment of snoring and/or daytime somnolence were assessed clinically and then underwent both unsupervised oximetry in their homes and formal polysomnography. Clinical assessment identified patients with an apnea+hypopnea index (AHI) > or = 15 events per hour with a sensitivity of 79% and a specificity of 50%. Home oximetry analyzed by counting the number of arterial oxygen desaturations recorded was inferior to clinical assessment. For desaturations of 2% or more from baseline, desaturation index (DI) > or = 15 per hour identified patients with AHI > or = 15 with sensitivity 65% and specificity 74%; for 3% desaturations, sensitivity was 51% and specificity 90%; and for 4% desaturations, sensitivity was 40% and specificity 98%. From the oximetry data, the percentage of time spent at SaO2 below 90% (CT90) was also calculated. CT90 > or = 1% identified patients with AHI > or = 15 with sensitivity 93% and specificity 51%; for patients with AHI > or = 15 ultimately given nasal continuous positive airway pressure (CPAP), the sensitivity of a CT90 > or = 1% was 100%. We concluded that home oximetry with CT90 < 1% practically excludes clinically significant OSA. Conversely, home oximetry with DI > or = 15 for 4% desaturations makes OSA likely: the positive predictive value for OSA is 83% if the pretest probability of OSA is 30% and over 90% if the pretest probability is at least 50%.

Adult↗
PubMed1990

Urinary uric acid:creatinine ratio, serum erythropoietin, and blood 2,3-diphosphoglycerate in patients with obstructive sleep apnea.

A noninvasive, inexpensive method of excluding significant sleep-associated hypoxemia would be desirable for patients being investigated and treated for obstructive sleep apnea (OSA). Sixty-eight such patients provided specimens before and after sleep studies for estimation of urinary uric acid:creatinine ratio (UA:Cr), serum erythropoietin (EPO), and blood 2,3-diphosphoglycerate (2,3-DPG). Mean (SD) morning 2,3-DPG was higher in 26 patients with overnight hypoxemia than in 42 normoxemic patients (2.54 [0.46] versus 2.24 [0.44] mmol/L; p = 0.01). Neither overnight change nor absolute values of serum EPO or urinary UA:Cr were significantly different between hypoxemic and normoxemic groups. There was a diurnal variation in serum EPO in normoxemic patients (P.M. EPO = 14.8 [7.1] mU/ml; A.M. EPO = 10.7 [7.1] mU/ml; p less than 0.05) but not in hypoxemic patients. Eighteen hypoxemic patients were restudied after using nasal continuous positive airway pressure (nCPAP) for at least 4 wk. Seven normoxemic patients not using nCPAP were restudied after a similar time. There were no significant differences between pretreatment and posttreatment nights in absolute values or percentage overnight change of blood 2,3-DPG or serum EPO in either group. In the hypoxemic (nCPAP) group, overnight change in urinary UA:Cr was lower on the second night (p = 0.04); there was no significant change in the control group. We conclude that although urinary UA:Cr, serum EPO, and 2,3-DPG may be physiologically related to hypoxemia, none of these measures can be used to predict accurately the presence of moderate nocturnal hypoxemia in patients with OSA or in monitoring the effect of their therapy.

2,3-Diphosphoglycerate↗
PubMed1989

Uvulopalatopharyngoplasty as a treatment for snoring.

Uvulopalatopharyngoplaty was performed in 18 consecutive patients (15 men and three women; mean +/- standard deviation [SD] age, 46.3 +/- 7.5 years) who presented for the treatment of heavy habitual snoring. No attempt was made to select patients who were ideal anatomically for palatal modification. The loudness of snoring was measured during sleep by integrating the output of a calibrated microphone. An assessment before operation showed that nine patients had obstructive sleep apnoea; four patients had an apnoea index of greater than or equal to 25 apnoeas per hour. The patients were overweight and consumed, on average, 38 g of alcohol per day, but these variables did not change after the operation. The postoperative assessment was performed 138 +/- 44 days after uvulopalatopharyngoplasty. Fourteen patients showed a reduction in the loudness of their snoring, although snoring was abolished in one patient only (average snoring loudness in arbitrary units/min of sleep, 2.8 +/- 2.1 before operation compared with 1.4 +/- 1.5 units/min of sleep after the operation; P less than 0.05. The loudest snore in arbitrary units measured 7.1 +/- 3.3 units compared with 4.8 +/- 3.3 units, respectively; P less than 0.05). The percentage of the sleep time that was spent at an arterial oxygen saturation of less than 90% was reduced after uvulopalatopharyngoplasty (28% +/- 32% of total sleep time compared with 17% +/- 24% of total sleep time, respectively; P less than 0.05). There was no change in the apnoea index. The diastolic blood pressure was lower at the postoperative assessment (94 +/- 11 mmHg compared with 87 +/- 8 mmHg; P less than 0.05); six of 10 subjects whose diastolic blood pressures were greater than or equal to 95 mmHg before the operation had a diastolic blood pressure of less than 95 mmHg after uvulopalatopharyngoplasty (P less than 0.02). Computed tomographic scans showed an increase in the upper airway cross-sectional area at 3 cm and 4 cm above the hyoid bone after uvulopalatopharyngoplasty (P less than 0.05). We conclude that uvulopalatopharyngoplasty is an effective treatment for habitual, heavy snoring in many patients, but it is not the treatment of choice for patients with clinically-significant obstructive sleep apnoea.

Adult↗
PubMed1987

Evaluation of a microprocessor-based portable home monitoring system to measure breathing during sleep.

Study of the epidemiology of disturbances of breathing during sleep was hampered until recently by the need to conduct studies in the laboratory, with attendant inconvenience and limited sample sizes. We assessed the accuracy of a microprocessor-based portable monitoring system (Vitalog PMS-8, Vitalog Corp., CA) to detect and classify episodes of disturbed breathing during sleep in 14 patients with sleep apnea by simultaneously recording oxygenation and thoracoabdominal motion on the portable system and a polygraph. Each patient slept in the laboratory for 1 night. In two subjects, the portable system failed to record thoracoabdominal signals. In the remaining subjects, the portable system detected 78% of 2,340 episodes of disturbed breathing, but the recorded information was not sufficient to allow confident classification into central or obstructive events. The positive predictive value of disturbed breathing detected by the portable system was 64%, Respiratory disturbance indices (RDI) computed from the polygraph and portable records were correlated (r = 0.70; p less than 0.01), and all patients with sleep apnea were correctly diagnosed by the portable system. The portable system overestimated arterial oxygen saturation (SaO2) recorded by an ear oximeter (Biox IIA, Ohmeda, CO) but the error was less than 10% of the true value at SaO2 greater than 60%. Seven normal subjects were studied while awake to examine the accuracy of volume measurements made by the portable system and the system's ability to detect paradoxical thoracoabdominal motion of various degrees. Absolute measurement of tidal volume was inaccurate, but detection rate of paradoxical thoracoabdominal motion was excellent (97%). We conclude that the portable system is sufficiently sensitive to allow detection of patients with breathing disorders during sleep, but further developments are necessary before the system can be relied on for accurate classification of apneas and hypoventilation.

Adult↗