Assessing Respiratory Variability During Mechanical Ventilation in Acute Lung Injury (ALI)

This study is currently recruiting participants. (see Contacts and Locations)
Verified August 2014 by Boston Medical Center
Sponsor:
Information provided by (Responsible Party):
Allan J. Walkey, Boston Medical Center
ClinicalTrials.gov Identifier:
NCT01083355
First received: February 19, 2010
Last updated: August 25, 2014
Last verified: August 2014
  Purpose

Healthy biological systems are characterized by a normal range of "variability" in organ function. For example, many studies of heart rate clearly document that loss of the normal level of intrinsic, beat-to-beat variability in heart rate is associated with poor prognosis and early death.

Unlike the heart, little is known about patterns of respiratory variability in illness. What is known is that, like the heart, healthy subjects have a specific range of variability in breath- to-breath depth and timing. Additionally, in animal models, ventilator strategies that re-introduce normal variability to the breathing pattern significantly reduce ventilator-associated lung injury.

Critically ill patients requiring mechanical ventilation offer an opportunity to observe and analyze respiratory patterns in a completely non-invasive manner. Current mechanical ventilators produce real-time output of respiratory tracings that can analyzed for variability.

The investigators propose to non-invasively record these tracings from patients ventilated in the intensive care units for mathematical variability analysis. The purpose of these pilot analyses are to: (1) demonstrate the range of respiratory variability present in the mechanically ve ventilated critically ill and (2) demonstrate the ventilator modality that delivers or permits the closest approximation to previously described beneficial or normal levels of variability. Future studies will use this pilot data in order to determine if the observed patterns of respiratory variability in mechanically ventilated critically ill subjects have prognostic or therapeutic implications.


Condition
Acute Lung Injury
Adult Respiratory Distress Syndrome

Study Type: Observational
Study Design: Observational Model: Case Control
Time Perspective: Prospective
Official Title: Assessing Respiratory Variability During Mechanical Ventilation in Acute Lung Injury

Resource links provided by NLM:


Further study details as provided by Boston Medical Center:

Primary Outcome Measures:
  • The degree of variability in tidal volume (measured as % variation about the mean) stratified by ventilator mode. [ Time Frame: 1 hour ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Alternative measures of variability and complexity for each ventilator mode. [ Time Frame: 1 hour ] [ Designated as safety issue: No ]
  • Correlations between clinical parameters such as disease severity, vital signs, sedation levels, and variability. [ Time Frame: 1 hour ] [ Designated as safety issue: No ]

Estimated Enrollment: 20
Study Start Date: March 2010
Estimated Study Completion Date: June 2017
Estimated Primary Completion Date: December 2016 (Final data collection date for primary outcome measure)
Groups/Cohorts
Mechanical ventilation
Critical care patients

Detailed Description:

Different modes of mechanical ventilation allow different levels of patient control of the respiratory pattern. For example, the most common mode of ventilation, called volume control, gives very little control to the patient in the amount of air taken for each breath. Other modes, such as pressure control, pressure regulated volume control and pressure support, allow more patient control of the volume of air delivered by the ventilator. Newer modes, such as airway pressure release ventilation (APRV), allow completely spontaneous patient respirations. All of these modes allow at least some patient control of respiratory rates.

Studies of natural breathing by healthy subjects have shown normal levels of variability in respiratory rate and tidal volume.1 Variability in physiological processes has been associated with health and the loss of variability can presage the onset of illness. For example, normal humans exposed to LPS (lipopolysaccharide-the potent immune-stimulating cell wall component of bacteria) lose their normal respiratory variability. Thus, physiological variability may represent a "hidden vital sign," the monitoring of which may herald important clinical events. Additionally, re-establishing normal levels of variability has therapeutic benefits in animal models. 2

The variability in respiratory patterns in ill patients has not been well studied. For example, it is currently unclear if critical illness results in deviations from normal variability patterns, if ventilator modes allowing increasing patient control of respiration allow patients to attain greater normalcy of respiratory variability, or if deviations from normal respiratory patterns while on ventilator modes which allow for increased levels of spontaneous breathing have prognostic implications.

The purpose of this pilot study is to record respiratory patterns from the ventilators of patients receiving various modes of mechanical ventilation in order to quantify and compare levels of respiratory variability associated with each mode. Our hypothesis is that APRV, a mode that allows spontaneous respiration, will be associated with respiratory variability patterns that most closely approximate that of normal subjects.

We hope that data derived from this study will inform future observational studies correlating respiratory variability during mechanical ventilation with severity of illness and prognosis.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population

Patients admitted to adult medical, surgical, and coronary critical care units at Boston Medical Center.

Criteria

Inclusion Criteria:

  • Age > or equal to 18.
  • Requires mechanical ventilation.
  • Admitted to surgical, medical, or coronary critical care unit
  • Triggering ventilator above set rate
  • Meets American European consensus definition of acute lung injury: PaO2/FiO2 ratio <300 or SaO2/FiO2 ratio<315; bilateral infiltrates on chest x-ray (CXR); no congestive heart failure (CHF).

Exclusion Criteria:

  • None
  Contacts and Locations
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, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01083355

Contacts
Contact: Phil Alkana, MA, RRT 617-638-8629 phalkana@bmc.org
Contact: Allan J. Walkey, MD 617-638-4577 alwalkey@bmc.org

Locations
United States, Massachusetts
Boston Medical Center Recruiting
Boston, Massachusetts, United States, 02118
Contact: Phil A;lama, MA, RRT    617-638-8629    phalkana@bmc.org   
Contact: Allan Walkey, MD    617-638-4844    alwalkey@bu.edu   
Sponsors and Collaborators
Boston Medical Center
Investigators
Principal Investigator: George O'Connor, MD Boston University
  More Information

Publications:
References Davis JN, Stagg D. Interrelationships of the volume and time components of individual breaths in resting man. J Physiol, 1975; 245:481-98. Goldberger AL. Heartbeats, hormones, and health: Is variability the spice of life? Am J Crit Care Med, 2001; 163: 1289-91.

Responsible Party: Allan J. Walkey, Assistant Professor of Medicine, Boston Medical Center
ClinicalTrials.gov Identifier: NCT01083355     History of Changes
Other Study ID Numbers: H-29278
Study First Received: February 19, 2010
Last Updated: August 25, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Boston Medical Center:
Variable ventilation
Pressure regulated volume control ventilation
Airway pressure release ventilation

Additional relevant MeSH terms:
Respiratory Distress Syndrome, Newborn
Respiratory Distress Syndrome, Adult
Acute Lung Injury
Lung Injury
Wounds and Injuries
Lung Diseases
Respiratory Tract Diseases
Respiration Disorders
Infant, Premature, Diseases
Infant, Newborn, Diseases
Thoracic Injuries

ClinicalTrials.gov processed this record on August 28, 2014