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).
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.
Eligibility
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
