Effects of Tracheal Tube Size on Pulmonary Aspiration

Study Overview
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Brief Summary
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Fluid leak around the cuff is minimized when the endotracheal tube size is small relative to the size of the trachea. In the current study, the investigators assess the influence of different HVLP endotracheal tube size on fluid leakage around the cuff in a benchtop model and in anesthetized patients.

Detailed Description
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The use of a high-volume and low-pressure (HVLP) endotracheal cuff has reduced the cuff-induced tracheal damage because the cuff conforms passively to tracheal contours as it expands during inflation and the cuff inflation pressure is assumed to be equal to cuff-to-trachea pressure. However, longitudinal folds of a HVLP cuff occur on inflation within the trachea, as the diameter of the cuff is greater than that of the trachea, and these folds provide channels for an aspiration or gas leakage. Silent aspiration of upper airway secretions has been reported in patients undergoing general anesthesia and in the intensive care unit (ICU). A previous study reported the 83% aspiration of subglottic dye detected by bronchoscopy in anesthetized patients, and other study of intubated patients with HVLP cuffs in the ICU showed 87% aspiration rate. Intubation-related (ventilator associated pneumonia) pneumonia is a leading cause of prolongation of hospital stay, mortality and morbidity during the postoperative period and in the ICU. Therefore, it is important to achieve a better seal around the cuff without tracheal damage, which would reduce the incidence of pneumonia in intubated patients. A previous benchtop study demonstrated that the leak around the cuff is minimized when the endotracheal tube size is small relative to the size of the trachea. In the current study, we assess the influence of different HVLP endotracheal tube size on fluid leakage around the cuff in a benchtop model and in anesthetized patients.

Official Title
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Effects of Tracheal Tube Size on Pulmonary Aspiration Different Endotracheal Tube Size Influences Pulmonary Aspiration

Conditions
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The Reduction of Aspiration Rate in Intubated Patients

Intervention / Treatment
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* Other: Observation of fluid leakage around tracheal tube cuffs


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male patients, aged 20-65 yr scheduled for elective cardiac surgery under general anesthesia Exclusion Criteria: Patients with an upper airway and vocal cord disease, pneumonia before surgery, a history of tracheostomy and tracheal stenosis.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Group ID 7.5<br>Patients with a tracheal tube ID (internal diameter) 7.5 mm | Other: Observation of fluid leakage around tracheal tube cuffs<br>* One milliliter of Evans blue diluted in 3.5 mL of saline solution is carefully instilled on the top of the tracheal tube cuff. In the operating room, one hour and five hours after intubation, fiberoptic bronchoscopy was performed to detect the possible presence of blue dye in the trachea. If a blue spot was seen on the trachea caudal to the tube's tip on any occasion, leakage was confirmed and the experiment was finished.<br>|
| Group ID 8.0<br>Patients with a tracheal tube ID 8.0 mm | Other: Observation of fluid leakage around tracheal tube cuffs<br>* One milliliter of Evans blue diluted in 3.5 mL of saline solution is carefully instilled on the top of the tracheal tube cuff. In the operating room, one hour and five hours after intubation, fiberoptic bronchoscopy was performed to detect the possible presence of blue dye in the trachea. If a blue spot was seen on the trachea caudal to the tube's tip on any occasion, leakage was confirmed and the experiment was finished.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Aspiration rate |  | during 5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Tracheal tube, Size