Assessment of Salbutamol Effect on Arterial Oxygenation in COPD Patients During One-lung Ventilation

Study Overview
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Brief Summary
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One-lung ventilation (OLV) is essential part of anesthesia during thoracic procedures. However, OLV induces a drastic increase of intrapulmonary shunt due to maintained pulmonary perfusion through the nonventilated lung, which may result in severe hypoxemia. Although the protective mechanisms of hypoxic pulmonary vasoconstriction favorably modulate pulmonary perfusion to the ventilated lung, the effect is attenuated in patients with history of chronic obstructive pulmonary disease (COPD), which alters compliance of the pulmonary artery. Salbutamol is a selective short-acting beta2-agonist and when inhaled during OLV, it acts selectively on the pulmonary vasculature reducing pulmonary vascular resistance of well-ventilated lung. We hypothesized that inhaled salbutamol would alleviate ventilation-perfusion mismatch during OLV of COPD patients, and aimed to assess the effects of salbutamol on oxygenation in these patients.

Official Title
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Assessment of Salbutamol Effect on Arterial Oxygenation in COPD Patients During One-lung Ventilation

Conditions
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One-lung Ventilation, Chronic Obstructive Pulmonary Disease

Intervention / Treatment
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* Drug: 5ml of inhaled normal saline
* Drug: 2.5mg (2.5ml) of inhaled salbutamol and 2.5ml of inhaled normal saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient age 40 80yrs, scheduled for videoscope-assisted pulmonary lobectomy American Society of Anesthesiologists Class III 또는 IV Moderate or more severe COPD according to GOLD criteria (FEV1/FVC<70%, FEV1<80%) Exclusion Criteria: New York Heart Association class >II AST level ≥100 IU/mL or ALT ≥ level 50 IU/L Creatinine clearance < 30mL/min History of severe coronary artery occlusive disease, unstable angina, or recent myocardial infarction within 6 months History of pulmonary hypertension or pulmonary edema History of cerebrovascular accident within 3 months

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control group<br>Normal saline | Drug: 5ml of inhaled normal saline<br>* After the initiation of OLV, 5ml of normal saline is inhaled for 20 minutes using ultrasonic nebulizer, which is connected to the inspiratory limb of the ventilator system. Arterial blood gas analysis is performed 30 minutes after the completion of drug inhalation.<br>|
| Experimental: Salbutamol group<br>Salbutamol + normal saline | Drug: 2.5mg (2.5ml) of inhaled salbutamol and 2.5ml of inhaled normal saline<br>* After the initiation of OLV, mixture of salbutamol 2.5mg and normal saline 2.5ml is inhaled for 20 minutes using ultrasonic nebulizer, which is connected to the inspiratory limb of the ventilator system. Arterial blood gas analysis is performed 30 minutes after the completion of drug inhalation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PaO2 (partial pressure of arterial oxygen) to FiO2 (fraction of inspired oxygen) ratio (P/F ratio) | The P/F ratio is a widely-used objective tool to identify hypoxemic respiratory failure when supplemental oxygen has been administered. It can be used to evaluate the effect of salbutamol on oxygenation during OLV. | Thirty minutes after the completion of drug inhalation |