I am a medical student though neither virology nor pulmonology are my expertise. As the global community gradually adopts isolation and social distancing the concern now rises regarding the availability of respirators.
As with any specialized equipment simply commandeering a factory and ordering it to manufacture respirators is not a reality: machines must be retooled, programming written, quality control perfected. It could easily take months before any functional respirators are produced under these circumstances.
While the needs would not be perfectly addressed, in the spirit of working with what is already on hand: would a CPAP machine be able to step in and provide O2 support for someone in mild-low/moderate respiratory distress?
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Image: CPAP next to ventilator.
CPAP would not suffice for someone requiring intubation but it may work to support a high risk/vulnerable patient in the early stages ensuring appropriate oxygenation and (possibly) shortening/bypassing the acute phase further exacerbated by low O2 saturation.
Consensus?
Image credit CPAP: https://www.smartnora.com/blogs/nora-blogs/cpap-machine
Image credit ventilator: https://www.usa.philips.com/healthcare/solutions/hospital-respiratory-care
Thank you for raising this interesting question.
CPAP is associated with worse outcomes in patients with pneumonia. It is also associated with more aerosolisation (and therefore more viral shedding) than high flow nasal oxygen therapy. CPAP is therefore not recommended for use in patients with COVID-19. It may be useful when attempting to wean ventilatory support after resolution of the viral infection.
Non-invasive ventilation also risks aerosolizing CoVID-19 particles.
Where CPAP has been tried in Covid-19 there are reports suggesting a high failure rate. So these patients eventually require intubation.
For these and several other reasons there should be a lower threshold for intubation in the critically unwell CoVID-19 patient.
The whole world is currently trying to solve the conundrum you raise. However, the issue of how many ventilators may be needed during the Covid-19 pandemic is more complicated than just simply considering the number of machines available.
It is possible to treat several patients with a single ICU ventilator. The Society of Critical Care Medicine guidance on this is below.
https://www.gnyha.org/news/working-protocol-for-supporting-two-patients-with-a-single-ventilator/
However all the patients would have to be deeply sedated to prevent triggering. Patients with similar needs for oxygenation and ventilation would have to be cohorted.
Anaesthesia Machines can also be used as ICU Ventilators. The Society of Critical Care Medicine guidance on this is below.
https://www.asahq.org/in-the-spotlight/coronavirus-covid-19-information/purposing-anesthesia-machines-for-ventilators
As most elective surgery has been cancelled many anaesthesia machines are lying idle and available for use.
Another option would be to use portable ventilators that are normally used to transfer patients around the hospital. These are generally more similar to ICU ventilators than the ventilators used in the anaesthesia machines.
The availability of portable ventilators is also limited. Portable ventilators are usually reserved for intra- and inter-facility transfer of patients.
Once all of these options have been exhausted the last resort would be to train patient's relatives to manually ventilate (‘bag’) patients. This is not uncommon in the developing world where ventilators are a scarce commodity at the best of times.
Whilst the use of medical students to ventilate patients during the Polio epidemic in Copenhagen in 1952 resulted in the birth of modern intensive care units I sincerely hope that we do have to face that scenario again.
The next question is then which of these options should be used first.
If patients require invasive mechanical ventilation and only the portable ventilators are available I would have no choice but to use them. Before using portable ventilators or using ICU ventilators to ventilate several patients I would use the anaesthetic machine ventilators in operating theatres. This would also allow the use of anaesthetic vapours for sedation of these patients. This may be critical when supplies of propofol and opiates are limited. Anaesthetic machines are generally kept within operating theatres so the use of these theatres also facilitates infection control.
After the anaesthetic machine ventilators were all used I would then start cohort ventilating up to 4 patients with similar degrees of lung injury per ventilator.
In conclusion: in principle I would prefer to use the operating theatre ventilators before cohort ventilating patients with ICU ventilators or using the portable ventilators. This is so that I can still perform inter- and intra-hospital transfers of ventilated patients.
However this decision making is complex and will vary with the resources available at individual centres. Modern intensive care ventilators are much more sophisticated than those used in operating theatres. ICU ventilators have many more modes of ventilation than operating theatre ventilators.
Some portable transfer ventilators are much more sophisticated than those used in operating theatres (e.g. Hamilton T1) and have the full functionality of intensive care ventilators. Some portable ventilators are less sophisticated (e.g. Oxylog 2000) than even the operating theatre ventilators.
Anaesthetic ventilators can function continuously and even allow the use of anaesthetic vapours for sedation. This may be relevant if supplies of propofol and fentanyl etc are depleted.
So whether it is safer to use the portable ventilator or the operating theatre ventilator depends on which of each type of ventilators you have. Regardless, in my experience, the humidification of gases using a HME (as is standard in the operating theatre and with portable ventilators) is not as effective as the wet circuit commonly used with ICU ventilators. So the risk of mucus plugging is higher.
Article Checklist Proformas to Guide and Document the Assessment of ...
The anaesthetic and portable ventilators are not as effective as intensive therapy unit (ITU) ventilators. Rather than using the same settings as we would with ITU ventilators, I therefore recommend that we adjust the settings on these ventilators according to frequent measurements of oxygen saturation, end tidal carbon dioxide, arterial blood gases, lactate and haemodynamic parameters. This is labour intensive and will require the assistance of staff who regularly care for ventilated patients but do not routinely work in ITU (i.e. anaesthetists).
So, as the COVID 19 pandemic progresses we will need to upskill colleagues to facilitate the assessment and treatment of critically ill patients with and without COVID 19. This may be achieved by face-to-face education sessions. However this is very labour intensive and may result in spread of COVID 19 amongst healthcare professionals.
An alternative approach would be to use standardised checklist proformas for the assessment of critically ill patients (see link below).
Article Checklist Proformas to Guide and Document the Assessment of ...
The use of checklist proformas can facilitate the management of critically ill patients by staff who do not routinely work in intensive therapy units. This could improve outcomes in this high risk cohort of patients and improve the confidence of staff redeployed to ITU from other care areas.
Home ventilation devices, non-invasive / invasive modes, there are many in the world also in Germany ...
these are a good alternative as therapy before the intensive care unit, see press conference with Dr.Voshaar.
https://www.facebook.com/wdrlokalzeitduisburg/videos/1124708497873001/
Thank you Dr. Voshaar finally an explanation that not everyone who comes to the KH does not need intensive care but that there are also preliminary stages in the therapies ...
Moist inhalation, oxygen or home ventilation at home ... no thought but why only Incomprehensible but apparently true
Unfortunately, at home with therapies with just moist nebulizers, O2, NIV (NON INVASIVE VENTILATION) from Corona patients as in z. B. COPD, ALS etc., not thought at all and therefore not carried out. Many of these required therapy devices are stored by the service providers and health insurers and could therefore be used in part immediately. Info Link OxyCare: https://www.oxycare-gmbh.de/index/aktuelles/coronavirus-(covid-19).html This is even a practicable, inexpensive way, but NO it is only thought in the pharmaceutical sense, right? TCM products and hydrogen oxygen obviously have a therapeutic effect ... Perspectives of the management of COVID-19 infection in China from European Respiratory Society (ERS) - ERSPlus 13-03-2020 Education: Video https://vimeo.com/395657458
Little or no attention to therapy / treatment observation from the lecture: TCM products and hydrogen oxygen obviously have a therapeutic effect ... among other things through anti-inflammatory, antioxidant and antiviral properties. Information: Prepared with the additional note on the possible fast outpatient / home care of corona infected patients with the appropriate devices for inhalation - oxygen supply - ventilation In my opinion, this path can relieve capacities such as beds, intensive care places, accessories and personnel as well as costs. Therefore, early use of physiotherapy, i.e. secretolysis, respiratory therapies and inhalation, e.g. b. Ambroxol (1) as well as giving oxygen (2) as I understand from this lecture prove to be very helpful and represents a simple and inexpensive possible alternative which can be used early and also in the outpatient / domestic area and prescribed by the treating doctor . (1) https://www.zeit.de/wissen/gesundheit/2020-03/coronavirus-heilung-impfstoff-medikamente-symptome-virus-infektion "If the first very serious course of illness occurs in Germany, and from a statistical point of view it can be assumed at some point, doctors like Martin Bommer can currently only do one thing: provide patients with oxygen first and, in the worst case, even provide artificial respiration. In fact, according to the World Health Organization (WHO), oxygen treatment is a key measure for a severe Covid 19 infection. ” (2) https://www.pharmaceutische-zeitung.de/ausgabe-382016/die-bedeutung-der-antiviralen-e Properties/
Perspectives of the management of COVID-19 infection in China Perspectives of the management of COVID-19 infection in China
I think Research Gate is finally keeping up with the demand of COVID-19 queries and the the community exchange of information. The site has so far blocked my efforts to extend my thanks to Rajkumar Rajendram and Peter Peschel .
Though (obviously) from my original question this is not my field of expertise I am very grateful for the time you have each taken to respond and clarify improved alternatives to my initial thought.
Spare time is precious these days. Thank you both for providing insight from your fields of knowledge.
I agree with Rajkumar Rajendran. We have used non-invasive ventilation and CPAP as a weaning mode to enable extubation and decrease levels of sedation in our COVID patient, once he tested negative ( twice by PCR in 2 samples 2h hrs apart) . It will need a close watch on the patient but might avoid many
complications of prolonged sedation and invasive ventilation.
In our experience CPAP used for patients with hypoxia but not decreased in level of consciousness, reduced the need for respiratory machines and also reduced the overall days for respiratory machines used if CPAP failed
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