1305 Awakening of a Complex Patient: Reversal of Hypoventilation and Cardiac Sequelae Following PAP Initiation

Abstract Introduction We describe a complex female patient with severe Overlap Syndrome (OHS and OSA) presenting with significant cardiometabolic repercussions. Report of case(s) A 44-year-old non-smoking, female presented with morbid obesity (BMI 47.6kg/m²), poorly controlled resistant hypertension, chest pain, and dyspnea. Her initial workup showed a normal ECG and negative cardiac troponins. Her blood pressure upon admission was 260x127mmHg. Arterial blood gas analysis revealed respiratory acidosis with metabolic compensation: PCO2=51 mmHg, HCO3=33.4 mmHg, and SO2=86%. Following emergency treatment, the mean arterial pressure was reduced by only 14.3%. Although her initial symptoms resolved completely, she continued to experience worsening blood pressure and oxygen saturation values during sleep, in addition to headache when saturation remained between 91-95%. She was instructed to sleep in a seated position following this initial assessment. Further diagnostic investigation revealed a Hypoxic Burden (HB) of 878%minutos/hora (considering the area under the curve of oxygen desaturation > 3%). Polysomnography (PSG) documented a total of 1011 respiratory events: 0 central and 1011 obstructive. The overall Apnea-Hypopnea Index (AHI) was 174.6/hour (141.8 apneas/hour and 32.8 hypopneas/hour). The REM AHI=152.7/hour. Baseline oxygen saturation was 98%; mean saturation was 69%, maximum was 98%, and minimum was a critical 41%. She spent 395.6 minutes (82.7% of the total sleep time) with SpO2 < 90%, 258.5 minutes (54%) with SpO2 < 80%, and 0.0 minutes (0.0%) with SpO2 < 70%. Conclusion During the therapeutic segment, our patient was initiated on PAP at 15 cmH2O. After just six weeks of treatment, follow-up revealed significant improvement, with the Hypoxic Burden reduced to 269%.minutos/hora and the Oxygen Desaturation Index (ODI) at 63. Despite being a critically ill patient, the combination of PAP therapy and multidisciplinary cardio-endocrinological monitoring led to a rapid improvement in her clinical status. The measurement of the Hypoxic Burden (HB), initially 878%.min/h, allowed for accurate monitoring as a clinical marker of impending life risk and cardiometabolic damage. The dramatic reduction of this parameter to 269%.min/h after only six weeks of PAP at 15 cmH2O demonstrates that, for high-risk patients, PAP is a cardiovascular and metabolic rescue therapy, not merely a sleep disorder treatment. Support (if any)