You have undoubtedly read or heard that we don’t have enough ventilators in this country to help Covid-19 victims breathe, especially in coronavirus hot spots like New York City, northern New Jersey, Detroit and New Orleans where hospitals need hundreds (if not thousands) of additional mechanized units.
Coronavirus Pandemic Causes Climate Of Anxiety And Changing Routines In America
In the face of this lopsided supply and demand dynamic, there is another more insidious problem lurking in that the prevailing design of manual ventilators (commonly known as Ambu bag resuscitators, which date from the 1950s) does not allow respiratory therapists or ambulatory technicians to precisely control the amount of oxygen that is pumped into the damaged lungs of those suffering from Covid-19. When you consider the incredible strain on first responders and medical staff in the throes of this pandemic, and the vulnerability of coronavirus patients, over-inflation of delicate lung tissues may well lead to routine violations of the Hippocratic oath: first do no harm.
As to the quantity conundrum, President Trump (finally) last week exercised his authority under the Defense Production Act (DPA) to supply components and compel manufacture of these critical devices. This will begin to address a severe shortage that may leave New York City hospitals without an adequate number of ventilators within days, even after California and Oregon have shipped ventilators east and the Federal government has distributed about half of the units stockpiled in the national reserve.
ResMed, one of the leading domestic manufacturers of ventilators, is “maximizing its production” of ventilators and bilevel non-invasive breathing machines, said CEO Mick Farrell.
ResMed Astral+RCM-NoCord Ventilator
Farrell emphasized that the rate-limiting issue that has slowed production acceleration has been their inability to gain “priority access to the [ventilator] components.” The DPA is intended to address this very issue, but the White House appeared reluctant to issue an executive order as the public health crisis intensified. For its part, ResMed said that it has been “actively engaging with key government officials” both here and abroad for weeks and that, notwithstanding any component supply limitations, it began ramping up production in early January as soon as the outbreak was detected in China. The company aims to double or even triple its annual production of ventilators and bilevels this year.
Another option to increase ventilator supply could be the conversion of Continuous Positive Airway Pressure (CPAP) or bilevel positive airway pressure (BiPAP or BPAP) machines typically used for treatment of sleep apnea.
A ResMed spokesperson suggested that this could be done but would require “significant rework to function as a ventilator.” A nascent effort to do just that is underway based upon work done by faculty at the University of California, Berkeley and the University of California, San Francisco. The effort appears to be consistent with new FDA guidelines that support “flexible . . . manufacturer modifications made to ventilators, anesthesia gas machines and other respiratory devices, and their accessories, in response to the COVID-19 public health emergency.”
Under a new schematic design co-developed by Berkeley mechanical engineering professor Grace O’Connell, the modified CPAP machine accepts oxygen where ambient air enters the device. The oxygenated air is then filtered and delivered to a patient through an FDA-approved endotracheal tube, and the exhaled air is re-filtered before being released. O’Connell emphasized that using an endotracheal tube bypasses the need for face masks, which could spread disease if aerosolized viruses escape.
A man wears a mask while walking past Sather Gate on the University of California at Berkeley campus … [+]
The Berkeley innovation has morphed into a volunteer community effort, led by two students and centered in the San Francisco Bay Area. The group is appealing to sleep apnea sufferers to donate their CPAP or BIPAP machines to be converted, and is optimistic that they can make an impact on addressing the shortfall based upon estimates that there are 8-10 million such machines in American households that could be converted. Notably, both the devices and components necessary to convert them are readily available and therefore could be put into the market more quickly than newly manufactured units.
Converted CPAP machines would not take the place of a mechanical ventilator employed in hospital intensive care units, but could be used in the field to supplement existing Ambu bags. These manually controlled bag ventilators are used to administer short-term respiratory support in ambulances and emergency rooms until patients can be placed on mechanical ventilators that deliver controlled breath sizes.
Currently, respiratory therapists (or worse, harried ambulatory or emergency professionals) must manually squeeze a hard, plastic balloon-like sphere to deliver air into the lungs of patients who can no longer breath sufficiently on their own. Many intuit that the lungs are simply empty vessels and that the risk to patients lies in providing too little oxygen, given the patient circumstances. But the bigger challenge is to do this cautiously so as to avoid lung hyperinflation that damages the delicate alveoli air sacs. This damage often is not apparent at the time but becomes evident within days as the body triggers an inflammatory response with severe implications that can lead to organ failure and death.
Peer reviewed publications on the advantages of so-called low-tidal-volume ventilation (and the costs and risks associated with excess volume ventilation) suggest that about 75,000 Americans die each year from complications associated with acute lung injury, more than die from breast and prostate cancer combined. Moreover, treatment associated with lung damage resulting from hyperinflation costs an estimated $20 billion per year.
In fact, no currently available bag used in the field promotes compliance to metrics established by the American Heart Association and the European Resuscitation Council, according to Dr. Michael Peck. Peck is a board-certified anesthesiologist and chief medical officer of AirMid Critical Care Products, a startup venture company focused on developing and commercializing an innovative volume-controlled manual ventilator. [In full disclosure, my law firm is advising the company on regulatory matters.]
“We have been working on this technology to promote guideline-compliant breaths from resuscitators for some time, but the coronavirus has given us a heightened sense of urgency to move from prototype to finished product as quickly as possible,” Peck said. “With the exposure to potential lung injury from non-compliant ventilators, we are focused on making a product that addresses this safety issue.” The company believes that widespread use of its guideline-compliant manual ventilators will reduce lung injuries and save massive healthcare system costs.
One intriguing, though perhaps unanswerable, question is whether deaths caused by acute lung damage will be wrongly attributed to Covid-19?
“I have had discussions with a number of my colleagues around the country, and some of us suspect that a portion of the death toll attributed to the coronavirus actually is being caused by excess manual lung inflation – whether in an ambulance or in a crowded hospital hallway – so that the patient’s lungs are irreparably harmed,” Peck noted. “This is yet another aspect of the tragedy of this ongoing public health crisis, but if we can build enough of these ventilators we may not need to make painful decisions as to who gets one and who doesn’t. This certainly won’t be our last pandemic.”