Mechanisms: CO2 handling and loop gain

In this episode of Talking Sleep, host Dr. Seema Khosla welcomes Dr. David McCarty, a sleep physician based in Colorado and Chief Medical Officer for REBIS HEALTH, to discuss the unique challenges of diagnosing and treating central sleep apnea at high altitude.

Living and practicing sleep medicine in Colorado has given Dr. McCarty extensive experience managing altitude-related central sleep apnea, a condition that affects many residents and visitors to elevated regions. The conversation begins with fundamental questions: Is central sleep apnea normal at altitude? What physiological mechanisms drive its development? Dr. McCarty explains the prevalence patterns across different elevations, from Denver's mile-high altitude to extreme elevations like 10,000 feet, and whether there's a threshold where everyone develops central events.

Practical diagnostic considerations receive detailed attention: Should patients be tested at their home altitude? How are titration studies conducted in high-altitude settings? What testing equipment best identifies central apneas, and should central hypopneas be scored? Dr. McCarty discusses the high prevalence of treatment-emergent central sleep apnea (TECSA) at altitude and how many patients present with mixed obstructive and central patterns, complicating treatment decisions.

The episode provides essential guidance for clinicians whose patients travel to high altitude destinations. What PAP adjustments should be made? How should EPR (expiratory pressure relief) settings be modified? Dr. McCarty walks through his decision-making framework for when to treat altitude-related central apnea, emphasizing the importance of patient education before ascension.

Treatment options are systematically reviewed: pressure adjustments, the role of BPAP therapy, when to consider ASV, acetazolamide use, and supplemental oxygen. Dr. McCarty discusses whether pre-emptive treatment is appropriate for patients planning high-altitude travel and provides practical protocols for managing both residents who live at altitude and visitors experiencing acute exposure.

The conversation emphasizes patient-centered approaches, considering not just the physiological aspects of altitude-related breathing disturbances but also the practical realities of treating patients in mountain communities and preparing lowland residents for high-altitude adventures.

Whether you practice in elevated regions, have patients who travel to altitude destinations, or simply want to understand the physiology behind altitude-related central sleep apnea, this episode provides essential clinical guidance.

Join us for this informative discussion about a condition that affects millions living at or traveling to high elevations.