The purpose of this pilot study is to measure the impact of non-invasive pneumatic manipulation of transthoracic pressure on oxygenation in patients with Acute Respiratory Distress Syndrome (ARDS) due to Coronavirus Disease 2019 (COVID 19) who are on mechanical ventilator support. This will be achieved by a pneumatic Vest placed around the chest wall of consenting patients who meet inclusion criteria. The Vest is essentially a non-invasive segmental device placed upon the anterior and posterior right and left aspects of the chest wall. The researchers have the ability to inflate and deflate the chambers of the Vest to achieve preset pressures as determined by the protocol and observe the patient's physiological response. Participants will have up to four hours of intervention with the study intervention, followed by 1 hour of post-intervention observation.
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