Clinical Effects of Intraoperative Heat and Moisture Exchange Systems During Thoracic Surgery: A Prospective Observational Cohort Study
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Active Heated Humidification, Heat and Moisture Exchanger.
- Who it may be relevant to
- Registry conditions: Video Assisted Thoracic Surgery (VATS), Postoperative Complications, Pulmonary Complications in Surgical Patients, Humidification. Basic parameters: 18 years — 75 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Turkey (Türkiye)
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
Clinical Effects of Active Versus Passive Intraoperative Respiratory Gas Humidification During Video-Assisted Thoracoscopic Surgery: A Prospective Single-Center Observational Cohort Study
Overview
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).
Detailed description
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.
Interventions
- Device Active Heated Humidification
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. - Device Heat and Moisture Exchanger
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.
Primary outcome measures
- Incidence of Postoperative Pulmonary Complications [Time frame: From completion of surgery through postoperative Day 7.]
Secondary outcome measures (11)
- Oxygenation (PaO₂/FiO₂ Ratio) [Time frame: Measured during one-lung ventilation and at the end of surgery.]
- Frequency of Endotracheal Suctioning [Time frame: From induction of anesthesia until completion of surgery.]
- Airway Secretion Viscosity Score [Time frame: During one-lung ventilation, at the end of one-lung ventilation, and within 24 hours after extubation.]
- Incidence of Intraoperative Hypothermia [Time frame: From induction of anesthesia until completion of surgery.]
- Incidence of Postoperative Hypothermia [Time frame: Within the first 24 hours after surgery.]
- Postoperative Oxygen Therapy Requirement [Time frame: Within the first 72 hours after surgery.]
- Requirement for Non-invasive Ventilation [Time frame: Within the first 72 hours after surgery.]
- Intensive Care Unit Length of Stay [Time frame: From ICU admission until ICU discharge, up to postoperative Day 30.]
- Hospital Length of Stay [Time frame: From surgery until hospital discharge, up to postoperative Day 30.]
- Bronchodilator Therapy Requirement [Time frame: Within 7 days after surgery.]
- C-Reactive Protein (CRP) [Time frame: Postoperative Day 7.]
Eligibility criteria
Inclusion criteria
- Patients aged 18 to 75 years
- Elective video-assisted thoracoscopic surgery (VATS)
- Lung resection requiring general anesthesia
- Planned one-lung ventilation
- Written informed consent
Exclusion criteria
- Emergency surgery
- Pregnancy
- Preoperative mechanical ventilation
- Previous enrollment
- Refusal to participate
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Observational model
- Cohort
Study locations
Turkey (Türkiye) · 1 center
- Marmara University — Istanbul
Identifiers
NCT: NCT07729319 · 09.2026.26-0220