0498 The Periodic Limb Movement During Sleep Related Ventilatory Pattern

Abstract Introduction Periodic limb movements during sleep (PLMS) are associated with repeated arousals and heart rate increases, suggesting sympathetic nervous system activation that could alter ventilation. Methods This retrospective, observational study evaluated breath-by-breath ventilation surrounding PLMS. NREM sleep epochs from polysomnograms with PLMS index (PLMI) ≥15 were analyzed. Validated signal processing algorithms analyzed EEG, leg EMG and nasal pressure data to identify PLMS, arousals, apneas, hypopneas and breath-by-breath ventilation. Ventilation (Vn) per breath was measured by integrating a square-root transformed nasal pressure signal over the breath’s duration, multiplying by respiratory rate and normalizing by 7-minute mean ventilation (baseVn). Vn=1.0 indicates ‘normal’ breathing; values above and below 1.0 indicate hyper- and hypoventilation. Each PLMS has an associated unique breath sequence: 6 breaths before (6B-1B), 1-2 breaths during (1D-2D), 8 breaths after (1A-8A) PLMS. Arousal was associated with PLMS when overlapping with 0.5 seconds before and after PLMS. Apnea or hypopnea were related to PLMS when overlapping with PLMS or breaths 1A-4A (PLMS-AH). PLMS-AH divided by hours NREM sleep (PLMS-AHI) ≥5 defined PLMS-related OSA (PLMS-rOSA). Results Seventy individuals (25 women) were 62.3±15.4 years old with BMI 32.5±8.4 kg/m2, median PLMI 73.3 and median AHI 14.8. 11 individuals had AHI< 5; 59 had AHI≥5. In total, there were 27,743 PLMS, 4,129 hypopneas and 2,679 apneas. 67.3% of apneas and hypopneas were PLMS-AH. 16.5% of PLMS were PLMS-AH; 31.9% for severe OSA. Median PLMS-AHI was 12.5. 78.6% of the cohort and 92.3% of OSA sufferers had PLMS-rOSA. Ventilation increased during PLMS and decreased following PLMS. For PLMS without arousal, Vn (medians) rose during PLMS to 1.07 (1D) and 1.05 (2D), while Vn fell after PLMS to a 0.91 nadir (4A). 1D-2D were significantly greater, while 2A-7A were significantly less than baseVn. For PLMS with arousal, Vn (medians) increased during PLMS to 1.35 (1D) and 1.40 (2D), and Vn fell to a 0.80 nadir (4A). 1D-2D and 1A were significantly greater, while 3A-8A were significantly less than baseVn. 39.6% of 4A breaths had Vn< 0.7. Conclusion Ventilation increased during PLMS and decreased following PLMS with larger magnitudes for PLMS with arousal. PLMS-rOSA was highly prevalent. Support (if any)