I’ll preface this with the fact that I am not a physician, nor am I in any way qualified to prescribe any type of respiratory support, other than emergently administer oxygen following a diving accident…
The latter part of that statement should resonate a bit – yes, the administration of therapeutic oxygen is a first line defense in any suspected pressure related diving injury. In fact, any layperson can be trained in how to operate a medical oxygen supply and administer it alone or while supplementing CPR. Oxygen is good for you – it’s good for all of us, in fact it is essential for life as we know it.
Like any drug, oxygen has to be managed responsibly, as there are dosage (time/exposure) limits for oxygen use. These human limits are well understood here at the surface, under varying amounts of pressure, and even in the absence of pressure (in a vacuum). The science behind this is very directly intertwined with the field of hyberbaric [elevated pressure] medicine and its associate hyperbaric oxygen therapy (HBOT).
Interestingly, any cause for loss of oxygen saturation within the body is reason to provide additional oxygen to the person to try and bring oxygen saturation back to normal levels. Just how much oxygen and for how long? Well, therein lies the science in the treatment and will revert to physicians. However, in diving, particularly in responding to an emergent situation, we accept that some oxygen is better than no oxygen, and have well accepted practices to do the best you can for as long as you can, and/or until a next line of medical intervention can be introduced.
In recent Covid-19 times, we’re in the very same boat, and should be following the physiology to treat effectively. It’s now well recognized that Covid-19 causes varying degrees of respiratory distress and possibly additional factors that consequently result in low oxygen saturation. Treating with elevated oxygen is critically important, but it also has to be delivered in an effective way. Some places are lucky and have endless supplies of oxygen produced by generators at the hospital, and then there is the other extreme where any substantial volumes of oxygen could be hours to days away. We divers understand this challenge well from trying to get mixed-gas supplies to remote areas – it’s not easy at that small scale, let alone trying to treat hundreds or thousands of people with high volumes.
One method for oxygen delivery to patients has proven quite effective for Covid-19, and it has evolved from the use of hoods for hyperbaric treatments. When inside of a hyperbaric chamber, you are under pressure, but generally surrounded by air. To supplement the patient with oxygen, it is both safer and most economical to confine the oxygen bolus to the head, and not flood the entire chamber. Enter Oxygen Treatment Hoods.. Outside of chamber use, these hoods can be used to create a little bubble around a patient’s head, and then serve three primary functions:
- the patient’s airway pressure can be increased, typically between 3 and 20 cm H20 (not high enough to cause damage). This pressure helps with lung recruitment, and I can speak from experience that it frankly feels quite good when testing things out.
- oxygen fractions can be elevated, and adjusted throughout the full spectrum from 21 to 100% oxygen. Since the bubble isolates the patient, this is a fairly small volume to manage.
- isolating the patients head (and airway) means that the healthcare worker is removed from the patients exhalations and any associated aerosols or secretions. Very simply, a viral filter provides the barrier of protection in between the patient’s bubble environment, and the outside world.
Simple = good. Elevate [pressure], oxygenate, protect. That’s all there is to helmet/hooded positive airway pressure (HPAP) ventilation..
The beauty of this ventilation solution is that it is non-invasive and benign enough to use proactively with patients experiencing early respiratory distress symptoms – there is no need to wait until intubation is required. In that regard, helmet ventilation might eventually be viewed as a first-aid type response, similar to our administration of oxygen during CPR. Time will tell.
Early Covid-specific reports are suggesting that this treatment alone is mitigating the need for more invasive ventilation – this is both a major cost savings to the healthcare community, and a relief to the strain on the hospital system.Patients in triage areas can potentially undergo helmet ventilation treatment, leaving hospital beds, ICU resources, and extensive staff teams available for the most severe of cases.
In areas that lack westernized hospital resources, helmet ventilation is quite likely the best respiratory intervention that can be delivered. More than 20 complete helmet ventilation systems can be deployed for less than the cost of a single sophisticated ventilator. That equates to more people treated, and potentially mitigating the more extreme cases requiring conventional ventilation while intubated.
Like anything new, ease of use is the important element for adoption. The entire process needs to be as simple as open the box and go, and without fear of screwing anything up. That means putting some common sense safety procedures in place, and also educating end-users. Leading the pack with this turn-key simple HPAP solution is VentilatorProject.org. Working with multiple partners, the project has distributed more than 600 turn-key solutions across multiple countries who are evaluating this concept within a cohesive study. The turn-key solution puts together conventional at-home CPAP devices with the Subsalve Oxygen Treatment Hood, and supplements the circuit with oxygen. More information can be found at www.ventilatorproject.org/getting-started.
To demonstrate the simplicity, VP put together a very nice video in cooperation with Dr. Alan Steinbach:
End-users should be careful to adopt the technique without first understanding some of the nuances with using CPAP units in this fashion – it remains experimental, and has nuances specific to various makes/models of CPAPs. A specific treatment protocol is being developed by expert physicians, and being evaluated for efficacy.
Again, simple = good, and in many settings soon to experience Covid-19 complications, this is a viable solution to ward off more severe respiratory distress, and possibly a step towards gross simplification of helmet ventilation to promote widespread acceptance.