The purpose of this pilot study is to measure the impact of non-invasive pneumaticmanipulation of transthoracic pressure on oxygenation in patients with Acute RespiratoryDistress Syndrome (ARDS) due to Coronavirus Disease 2019 (COVID 19) who are on mechanicalventilator support. This will be achieved by a pneumatic Vest placed around the chestwall of consenting patients who meet inclusion criteria. The Vest is essentially anon-invasive segmental device placed upon the anterior and posterior right and leftaspects of the chest wall. The researchers have the ability to inflate and deflate thechambers of the Vest to achieve preset pressures as determined by the protocol andobserve the patient's physiological response. Participants will have up to four hours ofintervention with the study intervention, followed by 1 hour of post-interventionobservation.
Since the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surfaced at the
end of 2019, transmission has been rapid and particularly lethal. Death is most commonly
due to ARDS which has been quoted as occurring in up to 42% of patients. The rapid
lethality of the COVID-19 has emphasized the limitations of currently available therapies
in the Intensive Care Unit. Traditional mechanical ventilator support, the use of inhaled
and systemic pulmonary vasodilatory drugs, invasive monitoring, proning and
extracorporeal membrane oxygenation (ECMO) to name a few, are all voracious consumers of
resources and have culminated in at least $27 billion expenditure per annum in the US
alone pre-virus. This fiscal burden has been far exceeded in the current pandemic. With
patient numbers growing exponentially hospital resources are being rapidly surpassed with
ICU's overflowing which is exacerbated by a national shortage of mechanical ventilators.
New techniques are demanded to both treat patients and identify responders if medical
resources are to be optimized.
Traditionally, patients present to the ICU and are intubated once a threshold of
respiratory distress and failure is reached. Various maneuvers are initiated to optimize
oxygen uptake by the lungs to prevent the onset of organ failure and death. At present,
there are no effective bridging technologies providing intervention between intubation to
these costly more complex techniques which are almost solely the purview of more
technologically adept tertiary academic centers. Clinical practice is often empiric and
driven by trial and error in this emerging disease, largely because there are presently
no clinical tests to provide clinicians with any clear indication as to which and whether
patients will respond to these more costly difficult procedures. This is in part due to
the underlying pathophysiology of ARDS where there is a further "uncoupling" between
bloodflow,(and hence uptake of oxygen), and healthy lung units which allow transfer and
absorption of oxygen because of the damage to the alveoli. This phenomenon shifts
physiologic Ventilation/Perfusion mismatch (V/Q mismatch) into a pathologic state. Since
this phenomenon is worsened by diseased tissue, it is diffuse but, not uniform and
response to therapy is difficult to determine based on current modalities. Thus, many
therapies are therefore instituted purely by trial and error. Determination of
appropriate candidates for advanced therapeutic techniques is critically important as
they are not without risk and resource consumption. Patients who are profoundly hypoxic
and fail traditional supine position support are "flipped" onto their abdomen to assume
the prone position, a technique known as proning. This requires a team of at least 6
nurses, respiratory therapists and physicians who attempt to ensure that there are no
adverse events. Such complications contribute to the morbidity and potential mortality of
the maneuver and include accidental extubation (displacement of the endotracheal tube out
of the trachea), disconnection from the ventilator, transient worsening hypoxia,
hemodynamic instability, dislodgement of central and peripheral venous catheters to name
a few. This is further compounded by the need for greater sedation which is itself
associated with hemodynamic instability, aspiration, altered conscious state and an
increase in acuity of monitoring making it much more labor intensive and expensive.
The researchers propose the development of a ventilation/ perfusion system, (V/Q System),
a pneumatically driven device which can improve oxygenation by adjusting trans-thoracic
pressure gradients. This is a new field of lung physiology which is only just being
explored. However, the concept of noninvasive manipulation of lung mechanics and
ventilation/perfusion mismatch is profoundly impactful as it potentially introduces a
comparatively safe technique to address an otherwise fatal failure of lung function. The
V/Q System represents an effort to optimize lung function without the risk of patient
proning. If successful, improved oxygenation associated with the device has multiple
clinical and economic ramifications. Initially, the device may obviate the need to more
costly, time consuming and potentially morbid procedures. Future research may include
investigating if the device may be utilized to identify both "responders" and
"non-responders" to advanced therapeutic techniques and can help eliminate the "trial and
error" approach in managing complex ARDS patients.
The study procedures will take up to 5 hours to complete for each participant enrolled.
During this time, the participant will be sedated per standard ICU protocol. Each study
participant will have up to 4 hours of intervention with the study V/Q System, followed
by 1 hour of post-intervention observation.
Device: V/Q System
With the patient supine, sedated, and hemodynamically stable, the Vest is placed upon the
patient and secured by clinicians and staff. All chambers of the Vest will be inflated
simultaneously. First inflation will be for one hour to a pressure of 0.4 psi. Subsequent
inflations at 0.8 and finally 1.2 psi will be performed for one hour each. Participants
will be treated for up to four hours and then will be observed for an additional hour.
Inclusion Criteria:
- Presentation with acute respiratory distress syndrome (ARDS) requiring intubation
with mechanical ventilator support. ARDS will be defined by the ratio of the partial
pressure of oxygen in the patient's arterial blood (PaO2) to the fraction of oxygen
in the inspired air (FiO2) as being < 300.
- Ability of a Legally Authorized Representative (LAR) to provide consent on behalf of
the patient.
Exclusion Criteria:
- Presence of cutaneous wounds that would be compromised by the Vest including stage 3
or greater pressure ulcers and the presence of actively treated burns
- Patients with pre-existing pulmonary hypertension and pulmonary fibrosis
- Bony chest trauma within the last 10 days
- Contraindications to esophageal manometry including recent esophageal trauma or
surgery
- Abdominal compartment syndrome
- Active or recent gross hemoptysis
- Elevated intracranial pressure >20 mmHg
- LAR refusal to participate
- Severe Scoliosis
- Morbidly obese (BMI >37)
- Pregnant women
- Unable to maintain oxygen saturation > 88%
Emory University Hospital
Atlanta, Georgia, United States
Maxwell Weinmann, MD, Principal Investigator
Emory University