Safety and Efficacy of Low-Flow ECMO in a Multi-modal Cohort of Adults in Respiratory Failure

Enrolling by invitation · Not applicable

Conditions studied: Acute Hypoxemic Respiratory Failure, Mechanical Ventilation, Acute Respiratory Distress Syndrome (ARDS)

In brief

The current standard of care (SOC) for treatment of patients with acute respiratory distress syndrome (ARDS), inhalation injury, volume overload, and/or pulmonary dysfunction is mechanical ventilation (MV). However, these techniques are associated with several complications after prolonged use, including risk of infection, increased sedation requirements, pulmonary edema, ventilator-induced lung injury (VILI), barotrauma, and multi-organ failure. Extracorporeal life support (ECLS) has been used to successfully minimize, replace, or avoid the use of MV. This concept is critical as it permits ultra-lung protective MV settings, mobilization, early ambulation of patients, and timely extubation (when appropriate). Conventional ECLS typically requires blood flows of 3-6 L/min, and its cannula sizes range from 21-25 Fr. This is by definition "high-flow" as it constitutes near-complete extracorporeal circulation of patient's circulating blood volume. On the other hand, low-flow ECLS at 1-2.5 L/min has been shown to prevent deleterious shifts in pH and PaCO2 at a lower level of invasiveness, and its cannula sizes range from 19-20 Fr dual lumen cannulas (which are associated with less serial dilation). The investigators propose the use of a low-flow circuit to include the NovaLung system in conjunction with a smaller tubing set and cannula to enable earlier utilization of ECLS with less invasiveness and smaller catheters. Specifically, the study will either utilize the Crescent RA cannula (or equivalent dual-lumen cannula) or use a 15-25 Fr cannula, both with 3/8 tubing/step-down tubing, as needed, for our study. A femoral (fem)-femoral or femoral-internal jugular (IJ) approach may also be used. Carbon dioxide is six times more diffusible than oxygen across the membrane; thus, carbon dioxide transfers can occur with high efficiency at our targeted blood flows of 1-2.5L/min. Oxygen can still transfer at these blood flows, and low flow can improve oxygen levels to some degree. There are three benchtop-based manuscripts that suggest that low-flow ECMO is associated with a potential increase in factors that increase the risk of bleeding complications/circuit changes. However, the manuscripts either tested \<1 L/min blood flow rates, or the effect of cannula size was not considered. None of them included the biological component of endothelial interaction. Mitigating the risk of bleeding complications by will be completed by administering anticoagulants with a target PTT of 40-50 seconds, and by monitoring the patients and their coagulation panels closely. There may be less risk of circuit clotting in our study because of chosen flow rates (1-2.5 L/min).

Key facts

Study ID

NCT06938217

Run by

Institute for Extracorporeal Life Support

People needed

30

Starts

2025-05-01

Expected to finish

2027-03-31

Last updated by the study team

2025-04-22

Who can join

Age: 18 and older, up to 65. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• Acute hypoxemic respiratory failure meeting all the following criteria:
• New or worsening respiratory symptoms developing within 2 weeks prior to the onset of need for oxygen or respiratory support
• Endotracheal mechanical ventilation for ≤ 5 days
• PaO2/FiO2 ≤ 200 mmHg for at least 6 hours, or for at least two readings one hour apart
• Male or non-pregnant female
• Admitted to the ICU at MHS
• Age ≥ 18 years

You may not qualify if…

• Hypoxemia is primarily attributable to fluid overload from acute heart failure
• Hypoxemia is primarily attributable to pulmonary embolism
• Hypoxemia is primarily attributable to status asthmaticus
• Extubation is planned or anticipated on the day of screening
• ICU discharge is planned or anticipated on the day of screening
• The patient is moribund and deemed unlikely to survive past 24 hours (as determined by the clinical team)
• The patient has limited code status, ordered for comfort measures only, or is in hospice
• Patients over 65 years of age
• Currently receiving any form of ECLS (ex. veno-venous, veno-arterial, or hybrid configuration)
• ΔPL-dyn ≤ 20 or Static ΔP ≤ 15 cm H2O while receiving VT 6 mL/kg (i.e. normalized elastance < 2.5 cmH2O/mL/kg)
• Chronic hypercapnic respiratory failure defined as PaCO2 > 60mmHg in the outpatient setting
• Home mechanical ventilation (non-invasive ventilation or via tracheotomy), not CPAP
• Severe hypoxemia with PaO2:FiO2 < 80mmHg for >6 hours at time of screening
• Severe hypercapnic respiratory failure with pH < 7.15 and PaCO2 > 60mmHg for >6 hours at time of screening
• Expected mechanical ventilation duration < 48 hours at time of screening
• Confirmed diffuse alveolar hemorrhage from vasculitis
• Contraindications to limited anticoagulation (ex. active GI bleeding, bleeding diathesis)
• Respiratory failure known or suspected to be caused by COVID-19
• Cirrhosis of the liver (as classified stage C of the Child-Pugh Score)
• Pregnancy
• Inability to tolerate extracorporeal therapy (MAP<65 mmHg despite fluid resuscitation and vasopressors)
• Unable to obtain informed consent from either patient or legally authorized representative (LAR)

Where it is running

• Methodist Healthcare System — San Antonio, Texas, United States

Full record on ClinicalTrials.gov

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