A Self-Experiment using "Air Battering Ram" (ASV + V-Com) to Treat Severe Loop Gain & Airway Collapse/Laryngospasm
Hi everyone,
I’m sharing an experimental, N-of-1 protocol I’ve developed to treat my highly complex sleep apnea.
I am dealing with severe high loop gain accompanied by centrally-mediated airway collapse/closure.
The underlying cause is likely neurogenic. My imaging shows vascular compression of the glossopharyngeal nerve (CN IX) at the medulla oblongata, which likely affects the vagus nerve (CN X) as well.
My Clinical Presentation:
My chemosensitivity to CO2 is extremely high. Even a slight CO2 fluctuation spikes my heart rate, disrupts my sleep, and triggers severe ventilatory overshoot / compensatory hyperventilation (with peak flows hitting 80-100 LPM), blowing off too much CO2.
When my respiratory drive drops to a certain threshold, my airway instantly collapses or locks up (suspected sleep-related laryngospasm). The ASV machine fails to push air into my lungs, leading to CO2 accumulation, micro-arousals, and yet another violent cycle of hyperventilation.
According to the PALM 4 Endotypes (Pathophysiological traits of OSA):
- Trait 1: Increased Upper Airway Collapsibility
- Trait 2: Increased Loop Gain
- Trait 3: Impaired Upper Airway Dilator Muscle Function
- Trait 4: Reduced Respiratory Arousal Threshold I score severely on Traits 2, 3, and 4.
Standard ASV + bleed-in oxygen + Acetazolamide failed to control my condition. The EERS (Enhanced Expiratory Rebreathing Space) mask was effective for my loop gain, but even with a dead space of <50ml, it caused unacceptable tachycardia and severe discomfort.
After long-term trial and error, I designed a two-pronged tactical approach:
Tactic A: "Biochemical Desensitization"
Goal: Blunt the CO2 sensitivity.
I used potent Carbonic Anhydrase Inhibitors (CAIs like Methazolamide / Sulthiame) combined with Telmisartan (to counteract the sympathetic/tachycardia side effects). The idea is to subject my central chemoreceptors to constant, high-intensity CO2 stimulation to desensitize them—similar to the physiological adaptation seen in early COPD patients or freedivers.
- Regimen: 25mg Methazolamide + 40mg Telmisartan (to prevent rapid heart rate and sweating) twice daily for 5 days as a loading/desensitization phase. Then reduced to a maintenance dose of 12.5mg Methazolamide twice daily. (I plan to transition to Sulthiame in the future).
- The Result of Tactic A: It successfully improved Trait 2 (Loop Gain) and Trait 4 (Arousals). My nighttime HR spikes and next-day fatigue decreased. However, it severely unmasked Trait 3. By lowering my CO2 sensitivity, my overall respiratory drive dropped, stripping away the compensatory muscle tone, leading to a massive spike in AHI due to airway collapse/closure.
The Inspiration for the Next Step:
To fix this "seesaw effect," I found inspiration in a common CPAP complication: Aerophagia (swallowing air due to excessive machine pressure). In treating aerophagia, the goal is to increase muscle tone (the upper esophageal sphincter) to prevent air from breaking through. My situation was the exact opposite: I needed the air to break through my locked airway.
So, I reverse-engineered the concept, leading to:
Tactic B: "The Air Battering Ram"
Goal: Physically force the locked airway open.
- Lowering the "Gate" Defenses: I use Ondansetron (or Baclofen) to reduce the airway closing muscle tone. This lowers the "defense" of the airway. Without this, the locked muscle tension is too high for the machine to break through.
- Setting up the Battering Ram: I set the ASV's PS max extremely high. When the airway locks, the ASV acts like a medieval battering ram, using high pressure to forcefully blast the airway open, similar to bag-valve-mask (BVM) rescue ventilation for laryngospasm.
- Installing the Safety Measure: I installed a flow-dependent resistor(1 or 2 V-Com ) inline. It provides dynamic, negative PS. When the airway is closed, the V-Com provides almost no resistance, allowing the ASV's high PS to hit the airway with zero pressure loss. But once the airway is blasted open and flow skyrockets, the V-Com creates massive resistance, dampening the flow and offsetting the high PS to prevent hyperventilation.
Observation/Hypothesis on V-Com: In actual tests, the total negative PS provided by the system felt lower than my math predicted. My theory: The airway is rarely blown completely open. Instead, it reaches a pressure-flow equilibrium. The still-narrowed airway acts as a native second resistor in series with the V-Com, providing additional negative PS to collectively blunt the hyperventilation.
- Current Settings for Tactic B: 8mg Ondansetron before bed. ASV set to PS 1-14 (Base PS 1 is to offset the V-Com's base resistance, making the actual delivered PS max ~11). 1x V-Com installed (with AB filter compensation turned on in the machine settings).
the \"Air Battering Ram\" test
The Result of Combining A + B:
Excellent. My AHI dropped from 6+ to consistently under 0.5. While this is still a highly experimental prototype, the underlying physics and pharmacology seem to be pointing in the right direction.
Deep Thoughts on V-Com and Aerodynamic Dampening
For a patient with my specific pathophysiology, a flow-dependent resistor like V-Com serves three critical functions:
- The Safety Buffer: It allows the safe use of dangerously high PS for the "battering ram" tactic.
- Instantaneous Dynamic PS: It reacts in milliseconds—faster than any ASV algorithm. It physically dampens mild flow instability before it can evolve into periodic breathing. It essentially gives even a non-ASV machine a hard-capped dynamic PS feature.
- Baseline Negative PS (Mask IPAP < Mask EPAP): It increases actual expiratory pressure (you can feel the mask inflate more on exhale). By making IPAP lower than EPAP, it gently suppresses breathing, retaining more CO2 to stimulate the respiratory drive. It acts like a tolerable, mild version of the EERS mask.
Therefore, an adjustable or custom-aperture flow dampener (perhaps modified via 3D-printed irises) would be a game-changer for high loop gain patients. (Based on my observations of the local patient community, there seem to be many).
The Math & The "Dual V-Com" Experiment:
Calculations show a single V-Com is sometimes insufficient. If an ASV pushes max PS ~11, and during a ventilatory overshoot the peak flow hits 60 LPM (+ 20 LPM mask vent leak = 80 LPM total flow), the pressure drop (ΔP) across the V-Com is about 4.5 cmH2O. This means the actual delivered PS is still around 6.5, which is slightly too high for me.
I tested putting 2 V-Coms in series to further cap the over-breathing.
My rig: V-Com --> Q-lite CPAP Muffler (to eliminate turbulence/whistling) --> V-Com --> 45cm short tube. (I also tricked the machine by setting the tube type to 3m or 15mm slim).
The Result: It eliminated mild breathing instabilities perfectly, BUT it caused a massive drop in the machine's trigger sensitivity, making it uncomfortable to breathe against.
(Note: The messy/unstable section in the middle of the 3rd graph was just a minor accident where my mask strap slipped off, causing a massive leak.)
The Future (Aerodynamics):
The current V-Com provides resistance proportional to the square of the flow rate (ΔP∝Q^2).
Theoretically, we need a higher-order non-linear dampener where resistance is proportional to the cube of the flow rate (ΔP∝Q^3). This would remain completely "invisible" at low flows (preserving machine trigger sensitivity) but act like a brick wall against high-velocity ventilatory overshoots.
Potential engineering solutions could involve a spring-loaded conical valve, a reverse-engineered duckbill valve (like those in BVMs), or designs utilizing the Bernoulli aspiration effect.
I’d love to hear the community’s thoughts
