NCT Number: NCT07729319
General anesthesia with endotracheal intubation bypasses the physiological warming and humidification functions of the upper airway, allowing cold and dry gases to reach the lower respiratory tract. This may impair mucociliary clearance, increase secretion viscosity, promote atelectasis, and contribute to postoperative pulmonary complications (PPCs).
Patients undergoing thoracic surgery, particularly those requiring one-lung ventilation (OLV), are at increased risk for PPCs because of altered ventilation-perfusion matching, reduced functional residual capacity, and impaired secretion clearance. Although respiratory gas humidification is routinely used during anesthesia, evidence regarding the comparative clinical effects of active heated humidification (AHH) and passive heat and moisture exchangers (HMEs) during thoracic surgery remains limited.
This prospective observational cohort study aims to evaluate the association between intraoperative respiratory gas humidification methods and postoperative pulmonary complications and perioperative clinical outcomes in adult patients undergoing elective video-assisted thoracoscopic surgery (VATS).
Interested in participating?
Request Info18 year–75 year
All sexes
Observational
Istanbul, 34722, Turkey (Türkiye)
Location status: Recruiting
Meliha Orhon Ergün, Associate Professor, MD
SUB_INVESTIGATOR
Nezaket Nur Arslan Kömür, MD
CONTACT
Nezaket Nur Arslan Kömür, MD
SUB_INVESTIGATOR
Seniyye Ülgen Zengin, Associate Professor, MD
CONTACT
Seniyye Ülgen Zengin, Associate Professor, MD
PRINCIPAL_INVESTIGATOR
The physiological conditioning of inspired gases is bypassed during general anesthesia with endotracheal intubation. Delivery of inadequately heated and humidified gases to the lower respiratory tract may impair mucociliary function, increase secretion viscosity, reduce airway patency, and promote postoperative pulmonary complications.
Patients undergoing video-assisted thoracoscopic surgery (VATS) frequently require one-lung ventilation, which further increases susceptibility to pulmonary complications through ventilation-perfusion mismatch, impaired secretion clearance, and atelectasis formation.
Two principal approaches are used for intraoperative respiratory gas conditioning:
Passive heat and moisture exchangers (HMEs) Active heated humidification systems (AHHs) Although HMEs are widely used because of their simplicity, they may provide insufficient humidification during prolonged procedures, high minute ventilation, or one-lung ventilation. Active heated humidifiers deliver gases closer to physiological conditions (approximately 37°C and 100% relative humidity), potentially reducing secretion viscosity and improving airway patency.
Most existing studies evaluating respiratory gas humidification have focused on intensive care patients receiving prolonged mechanical ventilation. Evidence regarding thoracic surgical patients remains limited, particularly during one-lung ventilation.
This prospective, single-center observational cohort study will compare perioperative outcomes among patients managed with active or passive humidification according to routine anesthetic practice. No intervention or randomization will be performed.
Healthy volunteers accepted: No
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Exclusion criteria
An active heated humidification system integrated into the anesthesia breathing circuit is used during intraoperative mechanical ventilation to warm and humidify inspired respiratory gases. Device selection and clinical management are determined solely by the attending anesthesiologist according to institutional routine practice. No study-specific intervention or modification of patient care is performed.
A passive heat and moisture exchanger filter is incorporated into the anesthesia breathing circuit during intraoperative mechanical ventilation to conserve heat and moisture from exhaled gases. Device selection is based on routine clinical practice, and no intervention is assigned by the study protocol.
Time frame: From completion of surgery through postoperative Day 7.
Incidence of one or more postoperative pulmonary complications occurring within 7 days after surgery, including atelectasis, pneumonia, secretion retention, bronchoscopy for mucus plugging, prolonged oxygen requirement, requirement for non-invasive or invasive ventilatory support, or reintubation. PPCs will be assessed using predefined clinical and radiological criteria.
Time frame: Measured during one-lung ventilation and at the end of surgery.
Intraoperative arterial oxygenation assessed by the ratio of arterial oxygen partial pressure (PaO₂) to the fraction of inspired oxygen (FiO₂).
Time frame: From induction of anesthesia until completion of surgery.
Number of endotracheal suctioning procedures performed during the intraoperative period.
Time frame: During one-lung ventilation, at the end of one-lung ventilation, and within 24 hours after extubation.
Airway secretion viscosity assessed using a semi-quantitative 5-point scale (0 = no secretions, 1 = watery secretions, 2 = mildly viscous secretions, 3 = thick secretions difficult to aspirate, 4 = very thick obstructive secretions). The highest score recorded for each patient will be used for analysis.
Time frame: From induction of anesthesia until completion of surgery.
Proportion of patients developing intraoperative hypothermia, defined as a core body temperature <36.0°C.
Time frame: Within the first 24 hours after surgery.
Proportion of patients with body temperature <36.0°C during postoperative monitoring.
Time frame: Within the first 72 hours after surgery.
Requirement for supplemental oxygen after surgery.
Time frame: Within the first 72 hours after surgery.
Requirement for postoperative non-invasive ventilatory support.
Time frame: From ICU admission until ICU discharge, up to postoperative Day 30.
Duration of admission to the intensive care unit.
Time frame: From surgery until hospital discharge, up to postoperative Day 30.
Length of hospitalization measured from the date of surgery until hospital discharge.
Time frame: Within 7 days after surgery.
Proportion of patients requiring bronchodilator treatment during the postoperative period.
Time frame: Postoperative Day 7.
Serum C-reactive protein concentration as a marker of postoperative inflammatory response.
Contact information is provided by the study sponsor or research team.
Nezaket Nur Arslan Kömür, MD
CONTACT
Seniyye Ülgen Zengin, Associate Professor, MD
CONTACT
Marmara University
Other
Clinical Effects of Active Versus Passive Intraoperative Respiratory Gas Humidification During Video-Assisted Thoracoscopic Surgery: A Prospective Single-Center Observational Cohort Study
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