Continuous Exhaled Breath Condensate pH in Mechanically Ventilated Patients

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00429637
Recruitment Status : Unknown
Verified August 2008 by University of Virginia.
Recruitment status was:  Recruiting
First Posted : February 1, 2007
Last Update Posted : August 7, 2008
Information provided by:
University of Virginia

Brief Summary:
Given the possible prognostic relationship between exhaled breath condensate pH and clinical symptoms, it is quite plausible that exhaled breath condensate pH can prove useful in the intensive care unit. For example, if exhaled breath condensate pH falls prior to the onset of clinical symptoms, it is likely that it can be useful as an early marker, heralding the onset of various inflammatory lung diseases. Specifically, exhaled breath condensate pH could be used as a safe, non-invasive screening tool for Ventilator Associated Pneumonia. Similarly, just as changes in exhaled breath condensate pH might predict the onset of disease, exhaled breath condensate pH changes might also mark the progression or resolution of disease (e.g. alerting clinicians to possible readiness for extubation). Although such notions are hypothetical, they are beginning to be supported by anecdotal evidence.

Condition or disease
Respiratory Distress Syndrome, Adult Respiratory Syncytial Virus Infections Pneumonia Acute Lung Injury

Detailed Description:

The investigators have developed a method of collecting exhaled breath condensate pH continually from ventilated patients, which (1) takes samples from an exhaust port on the outside of the ventilator circuit, and (2) possesses no measurable resistance to the ventilator circuit (and, therefore the sampling procedure in no way affects the patient).

Now, additionally, we have performed the continuous collection process on 10 patients in the intensive care units, none of whom have had any ill effects from the collection process.

The placement of the exhaled breath condensate collection device on the ventilator exhaust port offers a simplified, accurate, and safe method of investigating the relationships between airway pH and various pulmonary inflammatory disease processes in intubated patients of all ages.

In order to further extend our study of airway pH in intubated subjects, we believe it is necessary to obtain more frequent exhaled breath condensate pH measurements from intubated subjects. To that end, we have developed a collection system that will also measure the pH of the collected exhaled breath condensate in a fashion similar to the methodology used for thousands of assays in our laboratory and other laboratories globally. This involves deaeration of the sample to remove carbon dioxide. In the lab environment, this is performed with Argon. In the ICU setting, we will accomplish the same effect by using wall oxygen.

The continuous exhaled breath condensate pH collection and assay system consists of a condenser attached to the exhaust port of the ventilator. The condenser is kept chilled to slightly above freezing temperature by a refrigeration system commonly employed in ICU settings. The collection device stays attached to the exhalation port of the ventilator continuously, for hours to days.

Collected exhaled breath condensate is channeled into two deaeration chambers, through which wall oxygen is bubbled (total flow of 1 liter/min). In the second deaeration chamber, a micro pH electrode is inserted. This pH electrode is attached to a pH recorder that has internal memory that can record essentially an infinite number of measurements, allowing for any length duration of monitoring. This recorder has been evaluated by clinical engineering for radio frequency and other interference and is cleared for hospital use.

After measurement of pH, exhaled breath condensate is channeled into a waste chamber.

The breath condensate collection system is maintained chilled by a "hospital grade" Electri-Cool II model 767 refrigerated cooling system (or near-equivalent) that is clinically approved for use in the intensive care units. This device is approximately 30 cm on a side, and is kept on a wheeled cart out of the way of any clinical activity.

Hypothesis to be Tested: Clearly state the objectives and hypotheses and clearly define the primary and any secondary outcome measures.

  1. Exhaled breath condensate pH will have greater within-hour variability in subjects with lung disease than in subjects intubated for non-pulmonary reasons.
  2. Exhaled breath condensate pH will rise prior to readiness for extubation in infants and toddlers requiring mechanical ventilation for acute bronchiolitis.
  3. A decline in exhaled breath condensate pH or an increase in exhaled breath condensate pH variability will predict the onset of pulmonary inflammatory processes (such as ventilator-associated pneumonia) in those who initially require mechanical ventilation for non-inflammatory reasons.

Study Type : Observational
Estimated Enrollment : 120 participants
Official Title: Phase 2 Continuous Exhaled Breath Condensate pH in Mechanically Ventilated Patients
Study Start Date : December 2004
Estimated Study Completion Date : January 2009

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Any intubated patients, aged birth to adulthood, who are on a ventilator in any University of Virginia (UVA) intensive care unit.

Exclusion Criteria:

  • Control subjects may not be taking oral or inhaled steroids or have asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis, bacterial or viral pneumonitis, or adult respiratory distress syndrome (ARDS).

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00429637

Contact: Brian K Walsh, BS, RRT 434-243-9324
Contact: John F Hunt, MD 434-243-9324

United States, Virginia
University of Virginia Recruiting
Charlottesville, Virginia, United States, 22908
Contact: Brian K Walsh, BS, RRT    434-243-9324   
Contact: John F Hunt, MD    434-243-9324   
Sponsors and Collaborators
University of Virginia
Principal Investigator: John F Hunt, MD University of Virginia Identifier: NCT00429637     History of Changes
Other Study ID Numbers: 11618
First Posted: February 1, 2007    Key Record Dates
Last Update Posted: August 7, 2008
Last Verified: August 2008

Keywords provided by University of Virginia:
Airway acidification
Airway reconstruction

Additional relevant MeSH terms:
Respiratory Distress Syndrome, Newborn
Respiratory Distress Syndrome, Adult
Virus Diseases
Lung Injury
Acute Lung Injury
Respiratory Syncytial Virus Infections
Lung Diseases
Respiratory Tract Diseases
Respiratory Tract Infections
Respiration Disorders
Infant, Premature, Diseases
Infant, Newborn, Diseases
Thoracic Injuries
Wounds and Injuries
Pneumovirus Infections
Paramyxoviridae Infections
Mononegavirales Infections
RNA Virus Infections