Correlation Between PaCO2 and Respiratory Effort in Patients With COVID-19 With Extracorporeal Membrane Oxygenation

Excessive respiratory effort may cause self-inflicted lung injury (SILI) and inspiratory muscle injuries , stimulate desynchronization between the patient and ventilator , and worsen the perfusion of extrapulmonary organs . Appropriate respiratory drive and effort should be maintained during the treatment of patients with respiratory failure . In contrast, respiratory drive and effort are commonly increased in patients with COVID-19 pneumonia , and this phenomenon may persist in critically ill patients with COVID-19, even after receiving venovenous ECMO (vv-ECMO) support, owing to low pulmonary compliance and a high systemic inflammatory state .

To reduce respiratory effort and drive, ICU physicians often administer high doses of sedative drugs, analgesics, and muscle relaxants. The prolonged use of high doses of these drugs can cause loss of the spontaneous cough reflex, which in turn impairs sputum drainage and eventually worsens pulmonary consolidation and lung infections.

As the partial pressure of carbon dioxide in arterial blood (PaCO2) could affect the respiratory drive from the respiratory center (1), it has been shown that altering different levels of extracorporeal carbon dioxide removal in patients undergoing ECMO recovering from acute respiratory distress syndrome (ARDS) could alter respiratory drive. We hope to find a more appropriate target for maintaining PaCO2 to control respiratory effort in patients with COVID-19 undergoing ECMO.

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Key information

Conditions

COVID-19 Acute Respiratory Distress Syndrome Extracorporeal Membrane Oxygenation Complication Respiratory Effort-Related Arousal

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Peking Union Medical College Hospital

Beijing, Beijing Municipality, 100730, China

About this study

A stable environment was maintained during the study to avoid stress and abrupt stimulation.

Before the start of the study, sedative drugs were titrated to Richmond agitation sedation scale values of -3 to -2, an assisted breathing mode trial was conducted, and support pressure level were adjusted to achieve tidal volume < 6 mL/kg. The ECMO GF was adjusted to achieve stable baseline conditions, defined as PaCO2 < 40 mmHg, respiratory rate < 25 bpm, and peak airway pressure < 25 cm H2O. PEEP, fraction of inspired oxygen, pressure support ventilation (PSV), ECMO blood flow, and dose of vasoconstrictors, sedatives, and analgesics remained unchanged throughout the study.

The study protocol was initiated when the baseline parameters s were stable. The baseline parameters, including ventilation settings, arterial and arterial blood gas analysis, hemodynamics, and indicators of respiratory effort were measured in the baseline group. Then, the ECMO GF was modified to 50% of the baseline, and etCO2 values were monitored. ECMO GF was adjusted at 5-min intervals (increasing or decreasing by 0.5 L/min each time) until etCO2 stabilized at a level 5-10 mmHg higher than the baseline. After 20 min, the parameters were measured for the second time in the high-CO2 group (Figure 1).

The study was stopped if the heart rate (HR) was > 140 beats/min and/or respiratory rate was > 40 bpm and/or systolic blood pressure > 180 mmHg and/or patients experienced anxiety or diaphoresis.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Patients with COVID-19 who had undergone ECMO and pressure support ventilation (PSV) via tracheal intubation.

Treatment and study plan

PaCO2

Device

Level of partial pressure of carbon dioxide

Primary outcomes

Pressure muscle index

Time frame: Not exceeding 1 hour

During the pressure support mode, the inspiratory hold button was pressed and a physician performed an end-inspiratory occlusion maneuver. After a certain period, the patient completely stopped inspiratory effort. The difference between the end-inspiratory obstructive plateau pressure and pre-obstructive airway pressure (Paw) was used to estimate the patient's inspiratory effort and referred to as Pressure muscle index
airway pressure swing during occlusion

Time frame: Not exceeding 1 hour

is defined as the swing in the Paw generated by the force of the respiratory muscle under assisted ventilation when the airway is temporarily blocked (3). The expiratory airway occlusion of the ventilator was performed at random intervals during each recording. Each occlusion persisted for a single breath, as verified by the normal recovery of Paw. The maximum deviation of Paw from positive end-expiratory pressure (PEEP) during each occlusion was documented as airway pressure swing during occlusion

Sponsors and collaborators

Lead sponsor

Peking Union Medical College Hospital

Other

Registry information

Official study title

Correlation Between Level of Partial Pressure of Carbon Dioxide and Respiratory Effort in Patients With COVID-19 Undergoing Pressure Support Ventilation With Extracorporeal Membrane Oxygenation

Important dates

Study start: 2022
Primary completion: 2023
Study completion: 2023
First posted: May 31, 2023
Registry last updated: May 31, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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