Transpulmonary Pressure Gradients in High Frequency Oscillation (TPG in HFO)

Transpulmonary Pressure Gradients in High Frequency Oscillation Study

Patients with severe lung conditions occasionally require support with a special ventilator (breathing machine) called the High Frequency Oscillator (HFO). Effective ventilation requires that the pressure generated by the ventilator be as high as possible but not too high as this can damage the lungs. In patients on HFO, there is not a well defined way to measure this pressure. We will insert a small probe into the esophagus of patients on HFO to see if this is an accurate way to measure lung pressures for these patients. A better understanding of these pressures could lead to improved patient care.

Study Overview

• Status: Completed
• Conditions: Acute Lung Injury
• Intervention / Treatment: Other: Esophageal Pressure Monitoring

Detailed Description

Trials have found that the use of lower tidal volumes (6 ml/kg) during conventional mechanical ventilation decreases morbidity and mortality. Compared to conventional ventilation, high frequency oscillation (HFO) is able to provide much smaller tidal volumes (1.1 - 2.5 ml/kg) and thus theoretically may provide additional lung protection. At this time, while trials of HFO in adults have been inconclusive, the use of HFO for the management of ALI/ARDS has become widespread

Patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) are critically ill and have a high mortality associated with their illness (approximately 50%). Currently, esophageal pressure monitors are used to optimize inflation pressures and improve oxygenation in conventional mechanical ventilation in patients with ALI/ARDS. With this in mind, the purpose of this study is twofold: (1) demonstrate that esophageal pressure monitors can easily be inserted in patients undergoing HFO and (2) report the transpulmonary pressures in these patients.

• Study Type: Observational
• Enrollment (Actual): 7

Contacts and Locations

Study Locations

• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V5Z1M9
      • Vancouver General Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Critically Ill

Description

Inclusion Criteria:

• 19 years of age or older
• Receiving HFO
• Informed Consent Obtained

Exclusion Criteria:

• Esophageal lesions or esophageal surgery within the last 6 months
• Morbid obesity - defined as a Body Mass Index (BMI) > 40
• Unstable cervical spine injury or cervical spinal cord injury

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Critically Ill patients receiving HFO

Other: Esophageal Pressure Monitoring; An esophageal pressure monitor will be placed through the mouth into the esophagus by a study physician. Placement will be confirmed by a bedside chest X-ray. Once placement has been confirmed all air will be evacuated from the balloon by syringe. One ml of air will then be injected to partially inflate the esophageal balloon. Pleural pressure measurements will be recorded after 1 minute without spontaneous breathing or patient care related movement. This measurement will be repeated at 30 minutes and at 60 minutes after the first measurement. Trans-pulmonary pressure is calculated as the difference between esophageal pressure and mouth pressure. Once the measurements have been recorded, the catheter will be removed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
To demonstrate the proof of concept that esophageal pressures can easily be obtained in patients undergoing HFO.	60 minutes

Secondary Outcome Measures

Outcome Measure	Time Frame
To determine the transpulmonary pressure gradient in critically ill patients receiving HFO	60 minutes

Collaborators and Investigators

• Sponsor: University of British Columbia
• Investigators: Principal Investigator: William R Henderson, FRCPC, Universtiy of British Columbia

Study record dates

Study Major Dates

• Study Start: October 1, 2010
• Primary Completion (Actual): July 1, 2011
• Study Completion (Actual): March 1, 2013

Study Registration Dates

• First Submitted: March 21, 2011
• First Submitted That Met QC Criteria: March 21, 2011
• First Posted (Estimate): March 23, 2011

Study Record Updates

• Last Update Posted (Estimate): March 17, 2014
• Last Update Submitted That Met QC Criteria: March 14, 2014
• Last Verified: March 1, 2014

More Information

Terms related to this study

• Keywords: Oscillation; Transpulmonary pressure; HFO; High Frequency Oscillation
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases; Wounds and Injuries; Thoracic Injuries; Acute Lung Injury; Lung Injury
• Other Study ID Numbers: H10-02087