The Relationship Between Positive End Expiratory Pressure and Cardiac Index in Patients With Acute Respiratory Distress Syndrome (ARDS) Managed on a Fluid Protocol

The Relationship Between Positive End Expiratory Pressure and Cardiac Index in Patients With ARDS Managed on a Fluid Protocol: A Secondary Analysis of a Prospective Trial

The objective of this study is to evaluate the association between positive end-expiratory pressure (PEEP) setting and cardiac function, as measured by cardiac index, in patients with acute respiratory distress syndrome (ARDS) who were managed on the NHLBI ARDS Network Fluid and Catheter Treatment Trial (FACTT) fluid protocols.

Study Overview

• Status: Completed
• Conditions: Acute Respiratory Distress Syndrome (ARDS)

Detailed Description

This is a secondary cross-sectional analysis of the FACTT multi-center randomized controlled trial enrolling adult patients within 48 hours of ARDS onset from twenty medical centers across the US, some of which included more than one hospital. We studied the patients who were randomized to the pulmonary artery catheter arm of the FACTT study. The investigators included patients that had PEEP and cardiac index measurements performed within a short period of each other during the first 3 days of the FACTT study enrollment. Since FACTT had a 2x2 factorial design, half of the patients were in a 'liberal fluids' study arm, and the other half were in a 'conservative fluids' study arm.

• Study Type: Observational
• Enrollment (Actual): 367

Contacts and Locations

Study Locations

• United States
  • Connecticut
    • New Haven, Connecticut, United States, 06510
      • Yale University, School of Medicine, Department of Internal Medicine, Section of Pulmonary and Critical Care Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

This is a secondary cross-sectional analysis of the FACTT multi-center randomized controlled trial enrolling adult patients within 48 hours of ARDS onset from twenty medical centers across the US, some of which included more than one hospital. We studied the patients who were randomized to the pulmonary artery catheter arm of the FACTT study. We included patients that had PEEP and cardiac index measurements performed within a short period of each other during the first 3 days of the FACTT study enrollment.

Description

Inclusion Criteria:

Acute lung injury diagnosis (as defined by The American - European Consensus Conference on ARDS) of < 48 hours in duration.

Patients in the Pulmonary Artery catheter (PAC) arm of the FACTT study. PaO2 / FiO2 ratio of < 200. Data from the first 3 days of mechanical ventilation.

Exclusion Criteria:

Select chronic conditions that could independently influence survival (e.g., expected 6-month survival < 50%) and / or ventilator weaning.

PEEP values missing. FiO2 values missing. PaO2 values missing. Cardiac index values missing Pressors and / or inotropes requirement.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
High PEEP; Cohort of participants with positive end-expiratory pressure (PEEP) greater than or equal to 12cm.
Low PEEP; Cohort of participants with positive end-expiratory pressure (PEEP) less than 12cm.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Cardiac Index	The cardiac index is a cardiodynamic measure based on the cardiac output, which is the amount of blood the left ventricle ejects into the systemic circulation in one minute, measured in liters per minute (l/min). Cardiac output is indexed to a patient's body size by dividing by the body surface area to yield the cardiac index. The cardiac index which is the outcome measure is assessed at the same time as the PEEP (which is the independent variable) is measured. The study participants are NOT followed for any period of time. This is a cross-sectional study design. Both variables (Cardiac index and PEEP) are measured at the same time.	Cross sectional (i.e. at time Zero only)

Collaborators and Investigators

• Sponsor: Yale University
• Collaborators: University of North Carolina, Chapel Hill
• Investigators: Principal Investigator: Wassim H Fares, MD MSc, Yale University, School of Medicine, Department of Internal Medicine, Section of Pulmonary and Critical Care Medicine

Publications and helpful links

General Publications

• Fares WH, Carson SS; NIH NHLBI ARDS Network. The relationship between positive end-expiratory pressure and cardiac index in patients with acute respiratory distress syndrome. J Crit Care. 2013 Dec;28(6):992-7. doi: 10.1016/j.jcrc.2013.06.021. Epub 2013 Aug 28.

Study record dates

Study Major Dates

• Study Start: April 1, 2011
• Primary Completion (Actual): September 1, 2012
• Study Completion (Actual): September 1, 2012

Study Registration Dates

• First Submitted: October 19, 2012
• First Submitted That Met QC Criteria: October 25, 2012
• First Posted (Estimate): October 26, 2012

Study Record Updates

• Last Update Posted (Estimate): October 26, 2012
• Last Update Submitted That Met QC Criteria: October 25, 2012
• Last Verified: October 1, 2012

More Information

Terms related to this study

• Keywords: ARDS; acute lung injury; Mechanical ventilation; cardiac function; cardiac index; heart-lung interaction
• Additional Relevant MeSH Terms: Pathologic Processes; Respiratory Tract Diseases; Respiration Disorders; Lung Diseases; Disease; Infant, Newborn, Diseases; Lung Injury; Infant, Premature, Diseases; Syndrome; Respiratory Distress Syndrome; Respiratory Distress Syndrome, Newborn; Acute Lung Injury
• Other Study ID Numbers: NHLBI T32 HL007106-34