Detecting Lung's Closing Pressure by Capnography

General anesthesia is associated with loss of pulmonary functional residual capacity and the consequent development of atelectasis and closure of the small airway.

Mechanical ventilation in a lung with reduced functional residual capacity and atelectasis increased the dynamic alveolar stress-strain, inducing a local inflammatory response in atelectatic lung areas known as ventilatory-induced lung injury. This phenomenon may appear even in healthy patients undergoing general anesthesia and predisposes them to hypoxemic episodes that can persist in the early postoperative period.

Lung recruitment maneuvers restore the functional residual capacity and, therefore, protect the lungs from lung injury. A key issue in this kind of treatment is detecting the lung's closing pressure in order to maintain the end-expiratory pressure above such a limit.

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Key information

Conditions

Atelectasis Lung Diseases Pulmonary Atelectasis Respiratory Tract Diseases

Age range

18 year–70 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Hospital Privado de Comunidad

Mar del Plata, Buenos Aires, 7600, Argentina

About this study

This is a prospective and observational study designed to measure the lung's closing pressure. The investigators will study 20 mechanically ventilated patients scheduled for mediastinoscopy surgery under general anesthesia.

Lung mechanics and capnography will be assessed during surgery. A slow pressure-volume curve will be automatically performed by the ventilator, and the small airway closing pressure will be determined as the inflection point in the alveolar slope of the pressure-CO2 and volume-CO2 curves. Then, a lung recruitment maneuver will be applied following a descending positive end-expiratory pressure trial to determine the lung's closing pressure. The investigator will see if the lung's closing pressure found with these two techniques is similar.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

Age > 17 years ole
Programmed surgery

Exclusion criteria

Pregnancy
No programmed surgery
Hemodynamic instability
Severe COPD
Acute respiratory infection

Treatment and study plan

Slow pressure-volume curve

Diagnostic Test

Patients will be sequentially subjected to a slow pressure-volume curve and a lung recruitment maneuver

Other names: Lung recruitment maneuver

Primary outcomes

Airway pressure

Time frame: 30 minutes

Airway pressure will be measured at the airways opening and expressed in cmH2O.
Carbon dioxide

Time frame: 30 minutes

Expired carbon dioxide will be measured at the airways opening by a main-stream capnograph, expressed in mmHg.

Sponsors and collaborators

Lead sponsor

Hospital Privado de Comunidad de Mar del Plata

Other

Registry information

Official study title

Analysis of CO2/Volume and CO2-pressure Curves to Detect the Lung's Closing Pressure in Ventilated Patients

Important dates

Study start: 2023
Primary completion: 2025
Study completion: 2025
First posted: May 24, 2023
Registry last updated: May 16, 2025

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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Completed