Reply to Letter: One ventilator multiple patients—What the data really supports

Paladino, Lorenzo; Silverberg, Mark; Charchaflieh, Jean; Eason, Julie K.; Wright, Brian J.; Palamidessi, Nicholas; Arquilla, Bonnie; Sinert, Richard; Manoach, Seth

doi:10.1016/j.resuscitation.2008.06.010

Cited by 5 publications

(4 citation statements)

References 9 publications

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“…While each of these investigations have been criticized at length, 7,8 support for this idea continues. 9 We designed a lung model investigation of the concept of one ventilator for 4 patients, using mechanical lung analogues at varying levels of airway resistance and lung compliance. The goal of the trial was to determine the distribution of tidal volume (V T ) and end-expiratory lung volume in identical and varying "patient" characteristics.…”

Section: Introductionmentioning

confidence: 99%

Use of a Single Ventilator to Support 4 Patients: Laboratory Evaluation of a Limited Concept

et al. 2012

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INTRODUCTION:A mass-casualty respiratory failure event where patients exceed available ventilators has spurred several proposed solutions. One proposal is use of a single ventilator to support 4 patients. METHODS: A ventilator was modified to allow attachment of 4 circuits. Each circuit was connected to one chamber of 2 dual-chambered, test lungs. The ventilator was set at a tidal volume (V T ) of 2.0 L, respiratory frequency of 10 breaths/min, and PEEP of 5 cm H 2 O. Tests were repeated with pressure targeted breaths at 15 cm H 2 O. Airway pressure, volume, and flow were measured at each chamber. The test lungs were set to simulate 4 patients using combinations of resistance (R) and compliance (C). These included equivalent C and R, constant R and variable C, constant C and variable R, and variable C and variable R. Results. When R and C were equivalent the V T distributed to each chamber of the test lung was similar during both volume (range 428 -442 mL) and pressure (range 528 -544 mL) breaths. Changing C while R was constant resulted in large variations in delivered V T (volume range 257-621 mL, pressure range 320 -762 mL). Changing R while C was constant resulted in a smaller variation in V T (volume range 418 -460 mL, pressure range 502-554 mL) compared to only C changes. When R and C were both varied, the range of delivered V T in both volume (336 -517 mL) and pressure (417-676 mL) breaths was greater, compared to only R changes. CONCLUSIONS: Using a single ventilator to support 4 patients is an attractive concept; however, the V T cannot be controlled for each subject and V T disparity is proportional to the variability in compliance. Along with other practical limitations, these findings cannot support the use of this concept for mass-casualty respiratory failure.

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Section: Introductionmentioning

confidence: 99%

Use of a Single Ventilator to Support 4 Patients: Laboratory Evaluation of a Limited Concept

et al. 2012

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“…The potential to ventilate more than one patient with a single ventilator, a so-called split ventilator setup, has been proposed previously [2][3][4][5][6][7]. In its simplest form, the connected patients each get the exact same delivered pressures and inspiratory oxygen fraction.…”

Section: Introductionmentioning

confidence: 99%

Individualized mechanical ventilation in a shared ventilator setting: limits, safety and technical details.

Stiers¹,

Mergeay²,

Pinson

et al. 2020

J Clin Monit Comput

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The COVID-19 pandemic has resulted in an increased need for ventilators. The potential to ventilate more than one patient with a single ventilator, a so-called split ventilator setup, provides an emergency solution. Our hypothesis is that ventilation can be individualized by adding a flow restrictor to limit tidal volumes, add PEEP, titrate FiO 2 and monitor ventilation. This way we could enhance optimization of patient safety and clinical applicability. We performed bench testing to test our hypothesis and identify limitations. We performed a bench testing in two test lungs: (1) determine lung compliance (2) determine volume, plateau pressure and PEEP, (3) illustrate individualization of airway pressures and tidal volume with a flow restrictor, (4a) illustrate that PEEP can be applied and individualized (4b) create and measure intrinsic PEEP (4c and d) determine PEEP as a function of flow restriction, (5) individualization of FiO 2. The lung compliance varied between 13 and 27 mL/cmH 2 O. Set ventilator settings could be applied and measured. Extrinsic PEEP can be applied except for settings with a large expiratory time. Volume and pressure regulation is possible between 70 and 39% flow restrictor valve closure. Flow restriction in the tested circuit had no effect on the other circuit or on intrinsic PEEP. FiO 2 could be modulated individually between 0.21 and 0.8 by gradually adjusting the additional flow, and minimal affecting FiO 2 in the other circuit. Tidal volumes, PEEP and FiO 2 can be individualized and monitored in a bench testing of a split ventilator. In vivo research is needed to further explore the clinical limitations and outcomes, making implementation possible as a last resort ventilation strategy.

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“…The first descriptions of Co-venting multiple patients on a single ventilator were advanced by Neyman 2 and Paladino 3 . The use of Co-Venting has been tested in controlled, experimental models using test lungs, animals or human volunteers for brief periods [4][5][6][7][8][9][10][11][12] . Lately New York State Department of Health approved the ventilator splitting to treat dual patients with one machine 13 .…”

Section: Introductionmentioning

confidence: 99%

Adaptive split ventilator system enables parallel ventilation, individual monitoring and ventilation pressures control for each lung simulators

Hadar

Yarden²,

Leav³

et al. 2020

Preprint

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Objective:In mass crisis setting such as the COVID-19 pandemic, the number of patients requiring invasive ventilation may exceed the number of available ventilators. This challenge led to the concept of splitting ventilator between several patients, which aroused interest as well as a strong opposition from multiple professional societies (The joint statement) 1 .Establishment of a safe ventilator splitting setup which enables monitoring and control of each ventilated patient would be a desirable ability. Achieving independency between the Co-vent patients would enable effective coping with different individual clinical scenarios and broaden the pairing possibilities of patients connected to a single ventilator. We conducted an experiment to determine if our designed setup achieves these goals. Methods:We utilized a double two limbed modified ventilator circuits which were connected to dual lung simulators. Adding readily available pressure sensors (transducers), PEEP valves, flow control valves, one-way (check) valves and HME filters made the circuit safe enough and suitable for our goals. We first examined a single lung simulator establishing the baseline set parameters, while monitoring ventilator measures as Tidal Volume. The initial ventilator setting we chose was a controlled mandatory ventilation mode with a PIP (peak inspiratory pressure) of 25cmH2O, PEEP (Positive End Expiratory Pressure) of 5 cmH2O. In pressure control set at 20 cmH2O, the recorded mean TV( tidal volume) was 1000 mL (approximately 500 mL/lung simulator) with an average MV(minute ventilation) of 13 L/min (or 6.5 L/min/lung simulator). After examining the system with the dual modified circuits attached, and obtaining all the ventilation parameters, we simulated several clinical scenarios. We simulated clinical events such as: partial or full obstruction, disconnection, air leak and compliance differentials, which occur frequently on a ventilation course. Thus, it is a paramount system demand to keep undisturbed ventilation to the Co-vent patient A, while being challenged by patient B.

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Reply to Letter: One ventilator multiple patients—What the data really supports

Cited by 5 publications

References 9 publications

Use of a Single Ventilator to Support 4 Patients: Laboratory Evaluation of a Limited Concept

Use of a Single Ventilator to Support 4 Patients: Laboratory Evaluation of a Limited Concept

Individualized mechanical ventilation in a shared ventilator setting: limits, safety and technical details.

Adaptive split ventilator system enables parallel ventilation, individual monitoring and ventilation pressures control for each lung simulators

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