eISSN: 1731-2531
ISSN: 1642-5758
Anaesthesiology Intensive Therapy
Current issue Archive Manuscripts accepted About the journal Supplements Editorial board Journal's reviewers Abstracting and indexing Subscription Contact Instructions for authors Ethical standards and procedures
SCImago Journal & Country Rank

 
3/2021
vol. 53
 
Share:
Share:
more
 
 
Letter to the Editor

Saving lives by ventilating two patients with specific pressure-controlled ventilation from a single ICU-ventilator during the COVID-19 pandemic

Maxence Hureau
1
,
Maaike Versyck
1
,
Sylvie Fontainre
1
,
Fabien Lambiotte
1
,
Nabil El Beki
1
,
Piehr Saint Leger
1

1.
Centre Hospitalier de Valencienne, France
Anaesthesiol Intensive Ther 2021; 53, 3: 281–283
Online publish date: 2021/04/12
Article file
- Saving lives.pdf  [0.10 MB]
Get citation
ENW
EndNote
BIB
JabRef, Mendeley
RIS
Papers, Reference Manager, RefWorks, Zotero
AMA
APA
Chicago
Harvard
MLA
Vancouver
 
 
Dear Editor,
In late December 2019, SARS-CoV-2 was discovered, which is responsible for a new human disease called COVID-19. Among all laboratory-confirmed COVID-19 cases, 14% were hospitalized, with 2% admitted to intensive care units (ICU) with acute respiratory distress syndrome (ARDS) requiring mechanical ventilation [1]. SARS-CoV-2 has spread quickly across the world, with more than one hundred million confirmed cases and more than 2,500,000 dead. In March 2020, the Hospital of Valenciennes had to admit hundreds of COVID-19 patients, and its capacity was almost exceeded [2]. More recently, in France, thousands of critically ill patients had to be admitted to ICUs. In Europe, the next wave of COVID-19 pandemic could be more severe than the first one, and we already know that, in the case of increasing numbers of critically ill, some of them will die as a result of the unavailability of mechanical ventilators [3]. This shortage may be lessened if one ventilator could service more than one patient. The main worry is that this concept could be not useful and systematically deleterious for the patient. Some concepts have already been proposed to ventilate differently two circuits with a single ventilator, with several limitations like the lack of individualization of ventilation of each circuit [4–6]. More recently, in the face of the COVID-19 pandemic, Clarke et al. [7] described a new concept able to deliver specific ventilation for two different lung tests with a single ventilator. Again, Levin et al. [8] have recently shown that a similar concept of differential ventilation using a single ventilator with flow control valves is feasible in humans.
We would like to describe a different, novel, and cost-effective way of ventilating two patients with a single ICU ventilator using two circuits with different pressure controlled ventilation (Figure 1). We connected to the inspiratory valve of an ICU ventilator a T-piece (Figure 2 – A). This piece was connected to a Y-piece of flextube and connected to two pressure regulators (pressure range of 16 to 34 mbar) (Figure 2 – B), followed by an analogue pressure gauge (Figure 2 – C) and a second flextube connected to the test lung. On the expiratory circuit, a one-way valve was used (Figure 2 – D), followed by another T-piece (Figure 2 – A’), and finally the exhalation valve. The two circuits were similar. There is also a necessary specific shunt between the two T-pieces of the inspiratory and the expiratory valves to allow high inspiratory pressures (Figure 2 – E).
We tested it using SelfTestLungs (STL) (Dräger, Lübeck, Germany) and a modified STL (mSTL) with an elastic band to decrease its compliance. A gas wall-powered Evita respirator (Dräger, Lübeck, Germany) with a Bilevel Positive Airway Pressure (BiPAP) mode was used. The upper pressure levels of each circuit were set with the pressure regulator, and the lower pressure levels were the same for both circuits. The pressures of both circuits were measured in each filter with an invasive blood pressure transducer and displayed on a specific monitor. With two identical STLs and with a single upper pressure set on the ventilator, we showed that we can obtain two specific inspiratory pressures on each circuit regulated by pressure regulators (Figure 1). Moreover, the pressure of each circuit is independent.
With one STL and an mSTL, we observed that the delivered volume of each test-lung depends on the specific inspiratory pressure (set on a pressure regulator, and the upper pressure set on the ventilator is the same) and PEEP, with a high correlation between the two simulated lungs (r > 0.9, P < 0.05) and a very low standard deviation cycle after cycle. Finally, if we use one STL paired with mSTL as well as two identical STL, the global volume measured by the ventilator is equal to the sum of volumes of both test-lungs measured separately. The concept has some limitations, such as the fact that the respiratory rate, the fraction of inspired oxygen, and the PEEP level are the same for both patients, also that both patients need to receive neuromuscular blockade to limit triggering or the lack of individual alarms. At the same time, this solution has several advantages: the possibility to individualize the level of inspiratory pressure in order to deliver a specific volume to each patient, the non-return valve which enables patients to be disconnected independently while also minimizing the risk of any cross-infection, and the possibility to practice prone position or cardiac arrest resuscitation on only one patient. Additionally, this solution is relatively inexpensive (less than €600 per device), easy to reproduce, and potentially adaptable to different models of ICU ventilators. The ventilator splitting strategy will never be as performant as using a single ICU ventilator for a single patient, especially for weaning. It should be reserved as a short-term emergency solution and be used as a “short bridge” to more conventional ventilation strategies.
Although we have not tested our device in experimental or animal studies yet, due to the urgency of the situation some administrations may allow this concept, to avoid some ethical choices [9]. Our concept based on ventilating two test lungs using two distinct inspiratory pressure-controlled circuits connected to a single ventilator seems to be viable and cost-effective and may be life-saving. This potential to increase the capacity of ICUs, which differs from the standard of care, should lead to an ethical debate: Should we (potentially less effectively) ventilate more patients or focus on selected critically ill patients with better prognosis?

ACKNOWLEDGEMENTS

1. We thank Toyota Motor Manufacturing, the President Luciano Biondo, and engineers Erwan Le Pichouron, Laurent Laloux, and Rémi Dilimal, who made a substantial contribution to the study.
2. Financial support and sponsorship: none.
3. Conflict of interest: none.

References

1. Stokes EK. Coronavirus disease 2019 case surveillance – United States, January 22–May 30, 2020. MMWR Morb Mortal Wkly Rep 2020; 69: 343-346.
2. Defrancq F, Van Oost S, Lemtiri J, et al. Prise en charge COVID-19 au sein des soins critiques du plus important centre hospitalier général de France. Anesthésie & Réanimation 2020; 6: 440-454.
3. Rosenbaum L. Facing Covid-19 in Italy – ethics, logistics, and therapeutics on the epidemic’s front line. N Engl J Med 2020; 382: 1873-1875. doi: 10.1056/NEJMp2005492.
4. Cavanilles JM, Garrigosa F, Prieto C, Oncins JR. A selective ventilation distribution circuit (S.V.D.C.). Intensive Care Med 1979; 5: 95-98. doi: 10.1007/ BF01686056.
5. Neyman G, Irvin CB. A single ventilator for multiple simulated patients to meet disaster surge. Acad Emerg Med 2006; 13: 1246-1249. doi: 10.1197/j.aem. 2006.05.009.
6. Clarke AL. 3D printed circuit splitter and flow restriction devices for multiple patient lung ventilation using one anaesthesia workstation or ventilator. Anaesthesia 2020; 75: 819-820. doi: 10.1111/anae. 15063.
7. Clarke AL, Stephens AF, Liao S, Byrne TJ, Gregory SD. Coping with COVID-19: ventilator splitting with differential driving pressures using standard hospital equipment. Anaesthesia 2020; 75: 872-880. doi: 10.1111/anae.15078.
8. Levin MA, Shah A, Shah R, et al. Differential ventilation using flow control valves as a potential bridge to full ventilatory support during the COVID-19 crisis. Anesthesiology 2020; 133: 892-904. doi: 10.1097/ ALN.0000000000003473.
9. U.S. PUBLIC HEALTH SERVICE COMMISSIONED CORPS, Optimizing Ventilator Use during the COVID-19 Pandemic. Available at: https://www.hhs.gov/sites/default/files/optimizing-ventilator-use-during-covid19-pandemic.pdf.
This is an Open Access journal, all articles are distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0). License (http://creativecommons.org/licenses/by-nc-sa/4.0/), allowing third parties to copy and redistribute the material in any medium or format and to remix, transform, and build upon the material, provided the original work is properly cited and states its license.
Quick links
© 2021 Termedia Sp. z o.o. All rights reserved.
Developed by Bentus.
PayU - płatności internetowe