ity (FRC) in OSA patients, as lung volume has beendemonstrated to have an important effect on upper air-way mechanics during sleep.Materials and methods: We studied 10 OSA patients (age48 ± 9 y.o. BMI 37 ± 5 kg/m2, FRC 2.37 ± 0.86l) wear-ing a facial mask. Following sleep onset on CPAP, werecorded 1 h without treatment (baseline) and 1 h with10 cm H2O EPAP in random order, while measuringFRC (chest and abdomen magnetometers).Results: For baseline (no treatment) and EPAP, respec-tively, the mean apnea hypopnea index (AHI) was62.6 ± 28.7 and 56.8 ± 30.3 events per hour (NS), themean 3% desaturation index was 39.6 ± 33.6 and39.4 ± 31.8 events per hour (NS), the micro arousalindex was 63.3 ± 27.9 and 58.0 ± 26.6 events per hour(NS). The mean FRC change between baseline andEPAP was 13.3 ml (range 2–25 ml). Expiratory timewas increased with EPAP compared to baseline2.56 ± 0.86 vs. 2.18 ± 0.84 s (p = 0.009). Duty cycletended to be longer and minute ventilation lower withEPAP (p = ns for both).Conclusion: In OSA patients during sleep, the applica-tion of 10 cm H2O EPAP did not yield a decrease insleep disordered breathing and only marginallyincreased FRC, probably because of an increase in expi-ratory time.Funded by: HL48531, HL60292, NIH/NHLBI T32HLO07901, NIH/RR01032, Fond National Suisse dela Recherche Scientifique, Fondation SICPA, SocieteAcademique Vaudoise.

doi:10.1016/j.sleep.2006.07.116

P308 Arousal and gasping autoresuscitation compared to

reflex reversal of dysfunctions by gasp-like aspiration

reflex

Z. Tomori 1,*, V. Donic 1, S. Gresova 1, R. Benacka 1,

J. Jakus 2

1 Faculty of Medicine, Safarik University, Kosice2 Faculty of Medicine, Komensky University, Martin,

Slovakia

Objectives: Gasps often provide normalization of dis-rupted functions on arousal from sleep and can autore-suscitate asphyxic animals and humans. In order tofacilitate clinico-physiological implications of the gasp-like aspiration reflex (AR) analyzed in animals (Tomoriet al. J Physiol 2005, Proceedings 567P,PC92), arousalfrom sleep disordered breathing (SDB) associated oftenwith gasps, have been compared with autoresuscitationby gasping and revival effects of AR in cats.Material and methods: Evaluation of 25 parametersfrom polysomnograms in 230 adults differentiated 5stages of SDB graded by apnea/hypopnea index (AHI

<3/h, 3–10/h, 10–20/h, 20–40/h, >40/h) as snoring,upper airway resistance syndrome and sleep apnea/hy-popnea syndrome 1,2,3. Their arousal effects were com-pared with changes of cardio-pulmonary-cerebralfunctions induced by spontaneous gasping and upperairway stimulation in anesthetized cats from severalexperiments.Results: Severe SAHS (AHI 57.1 ± 1.6, M ± SE) hadhigher respiratory (91.5 ± 10.2/h) and movement arous-als (32.5 ± 4.5/h), and sleep fragmentation index(36.9 ± 3.1/h), which were associated with lower average(84.5 ± 1.1%) and minimal O2 saturation (55.4 ± 2.1%)and higher oxygen desaturation index (49.4 ± 4.2/h),than four milder groups (p < 0.05–0.001). Analysis ofresults revealed positive correlations of AHI with respira-tory arousal (r = 0.68), periodic breathing (r = 0.42) andODI (r = 0.58) and negative correlation with MinSaO2

(r = �0.69) and AvgSaO2 (r = �0.52). The gasp-likeAR induced on demand from the upper airways provedto interrupt various cardio-respiratory and neurobehav-ioral disorders, e.g., bronchoconstriction (Tomori Z,Widdicombe JG. J Physiol 1969,200:25–49), hypoxicapnea (Tomori et al. Eur Respir J 1991,5:1117–25, etc.)by influencing 14 of 35 brainstem identified nuclei (Jakuset al. Physiol Res 2004,53:703–17).Conclusion: Arousal from severe SAHS and autoresusci-tation from asphyxia result from hypoxemia and mani-fest as solitary gasps or persistent gasping, which cannormalize various dysfunctions or renew failing vitalfunctions. The gasp-like AR can provide similar effectsby reflex revival of failed cardio-pulmonary-cerebralfunctions in animals and probably also in humans viaits analog – the airway dilatory reflex.

doi:10.1016/j.sleep.2006.07.117

P309 Sleep and psychologic disorders in patients with end-

stage renal disease undergoing hemodialysis

Mohamad Amin 1, Abd El-Baset M. Saleh 2,*, El-Sayed

Saleh 3, Alaa Sabry 4, Khaled Mahmoud 4, Khaled El-Dahshan 4, Ahmed Hassan 4

1 Pulmonary, Critical Care and Sleep Medicine Attend-

ing, VAMC, Northport, NY/Assistant Professor, Stony

Brook University, NY, USA2 Thoracic Medicine Department ‘‘Lecturer’’ (Sleep Dis-

ordered Breathing Unit), Faculty of Medicine, Mansoura

University, Egypt3 Psychology Department, Faculty of Medicine, Manso-

ura University, Egypt4 Nephrology Department, Faculty of Medicine, Manso-

ura University, Egypt

Objectives: (a) To determine the prevalence of sleeprelated complaints and psychological disorders among

Abstracts / Sleep Medicine 7 (2006) S1–S127 S45

patients with ESRD on HD and its correlation with lab-oratory, clinical and/or demographic data.

(b) To measure the prevalence of psychological disor-ders on sleep in patients with ESRD on HDMethod: Eighty-eight patients with ESRD on HD wereenrolled in the study.

Demographics, laboratory and dialysis data wererecorded.

Using a self-administered questionnaires we assessedthe presence of the following sleep complaints: insom-nia, restless legs syndrome (RLS), excessive daytimesleepiness (EDS), sleep walking and psychological disor-ders by using anxiety and depression scale.

Patients were divided into two groups: with (sleep +)and without (sleep �) sleep complaints and according tothe etiology of ESRD to diabetic and non-diabetic.Results: The questionnaire revealed the presence of sleep+ in 83 patients (94.3%), insomnia in 79 patients(88.8%), RLS in 41 patients (46.59%), OSAS in 28patients (31.8%), EDS in 24 patients (27.3%), cataplexyin 17 patients (19.3%) and sleep walking in 3 patients(3.4%).

The psychological disorders were anxiety in 9 patients(10.2%), depression in 9 patients (10.2%), and psychoso-matic complaints in 5 patients (5.7%).

Both anxiety and depression were statistically signifi-cant among ESRD patient with sleep complaints vs.who don’t have with P value of (<0.05 and <0.05),respectively.

Among patients reporting RLS in hypoalbuminemiaand anemia were statistically significant among patientreporting RLS vs. who do not have it with P value<0.05 and <0.01, respectively.

There was a significant increase in sleep disorders andsnoring among diabetic patients as an etiology of theirESRD with P value <0.05 compared with non diabeticsetiology of ESRD.Conclusion: Diabetic ERDS patients on hemodialysishave high predominance of sleep disorders and snoring,we are in need for more studies to determine the patho-physiology of this phenomenon.

Patients with hyponatremia are less sleepy during theday. There is an increase in RLS in anemic, malnour-ished ERDS patients on hemodialysis.

Insomnia, RLS, EDS and psychological disorders arecommon among ERDS patients on hemodialysis.

doi:10.1016/j.sleep.2006.07.118

P310 Timing of changes in oxyhemoglobin saturation

resulting from breath holding

Scott Sasse 1, Philip Westbrook 2, DanielLevendowski 2, Tim Zavora 2, Roy Dalati 2, Cindy

Vincent 1, Miodrag Popovic 1

1 Long Beach VA Medical Center, CA, USA2 Advanced Brain Monitoring, Inc., Carlsbad, CA, USA

Objectives: Hypopneas are commonly defined as an eventlasting 10 s or more with at least a 30% reduction in tho-rocoabdominal movement or airflow, and with at least a4% oxygen desaturation. In this study, the investigatorsassessed the anthropomorphic and lung volume influenceon the ability to achieve a 4% desaturation.Materials: Eighteen male and two female healthy sub-jects completed three breath hold (BH) trials from func-tional residual capacity. Supine lung volumes weremeasured using the nitrogen wash-out technique. Arteri-al blood was sampled at 5-s intervals from a radial arteryline during and for 20-s after the end of each breath hold.Oxyhemoglobin saturation was measured using a BayerModel 845 CoOximeter. A cubic spline interpolationwas used to predict the time and depth of the oxyhemo-globin nadir and to estimate data points representative ofeach 1-s period during the breath holds. For each trialSaO2 values were calculated at 5-s intervals from the startof the BH until breathing resumed, and from the oxyhe-moglobin nadir at 3-s intervals for 18-s. The mean SaO2values were then computed by subject across trials. Cor-relations between the SaO2, anthropomorphic, and lungvolume measures were calculated.Results: Weight (mean 195 ± 37.3) and body mass index(BMI) (mean 27 ± 4.4) were positively correlated withthe length of time between the start of the breath-holdand the oxyhemoglobin nadir (mean 46 ± 6.3 s)(p < 0.01). Weight and BMI were negatively correlatedwith functional residual capacity (in liters) (FRC)(p < 0.01). FRC was positively correlated with the

S46 Abstracts / Sleep Medicine 7 (2006) S1–S127