Effects of High and Low Tidal Volumes on Arterial Oxygenation and Pulmonary Shunt During One-Lung Ventilation

Study Overview
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Brief Summary
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The ideal tidal volume (TV) during one-lung ventilation (OLV) remains controversial. High tidal volumes may increase the incidence of postoperative lung injury after thoracic surgery. The investigators thus evaluated the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during OLV. One hundred patients scheduled for thoracic surgery were enrolled. During OLV, patients were randomly assigned to 30 minutes of ventilation with high TV (10 ml/kg with zero end-expiratory pressure (ZEEP)) at a rate of 10 breaths/minute or low tidal volume (5 ml/kg with 5 cm H2O positive end-expiratory pressure (PEEP)) at a rate of 20 breaths/minute. During the subsequent 30 minutes, each patient received the alternative management. Minute volume was thus kept constant during each experimental condition. Arterial blood partial pressures, hemodynamic responses, and ventilatory parameters were recorded. Results are presented as means ± SDs; P < 0.05 was considered statistically significant.

Conditions
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Postoperative Lung Injury

Intervention / Treatment
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* Other: high tidal volumes
* Other: low tidal volume


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA I-III patients scheduled for lung resection surgery. Exclusion Criteria: severe cardiovascular disease severe alteration of the preoperative pulmonary function, with FEV1 70-120% predicted and FEV1/FVC ≥ 70% predicted considered to be normal.

Ages Eligible for Study
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Minimum Age: 18 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: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: high (10 ml/kg) tidal volumes<br>Evaluate the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during one lung ventilation. | Other: high tidal volumes<br>* One-lung ventilation was started at skin incision using a volume-controlled square-wave flow pattern. Patients were randomly assigned to 30 minutes of ventilation with a tidal volume of 10 ml/kg tidal volume without external PEEP and respiratory rate of 10 breaths/minute (n=50) or to a tidal volume of 5 ml/kg with 5 cmH2O PEEP and a respiratory rate of 20 breaths/minute (n=50). Minute volume was thus kept constant during each experimental condition. Randomization was based on computer-generated codes that were maintained in sequentially numbered sealed opaque envelopes until after induction of anesthesia. During the subsequent 30 minutes of one-lung ventilation, the alternative ventilatory management was used.<br>|
| Active Comparator: low tidal volume (5 ml/kg)<br>Evaluate the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during one lung ventilation. | Other: low tidal volume<br>* One-lung ventilation was started at skin incision using a volume-controlled square-wave flow pattern. Patients were randomly assigned to 30 minutes of ventilation with a tidal volume of 10 ml/kg tidal volume without external PEEP and respiratory rate of 10 breaths/minute (n=50) or to a tidal volume of 5 ml/kg with 5 cmH2O PEEP and a respiratory rate of 20 breaths/minute (n=50). Minute volume was thus kept constant during each experimental condition. Randomization was based on computer-generated codes that were maintained in sequentially numbered sealed opaque envelopes until after induction of anesthesia. During the subsequent 30 minutes of one-lung ventilation, the alternative ventilatory management was used.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| low (5ml/kg) tidal volume on arterial oxygenation | Evaluate the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during one lung ventilation. | 30 minutes of ventillation | 
| high (10 ml/kg) tidal volumes on arterial oxygenation | Evaluate the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during one lung ventilation. | 30 minutes of ventillation | 
| low (5 ml/kg)tidal volumes on Intrapulmonary shunt | Evaluate the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during one lung ventilation. | 30 minutes of ventillation | 
| high (10 ml/kg) tidal volumes on Intrapulmonary shunt | Evaluate the influence of low (5 ml/kg) and high (10 ml/kg) tidal volumes on arterial oxygenation and Intrapulmonary shunt during one lung ventilation. | 30 minutes of ventillation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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OLV, one lung ventilation