The Distribution of Pressure in the Thorax During Mechanical Ventilation and Its Effects on the Circulation

Fluid administration is a daily intervention on the intensive care unit to improve cardiac output (CO) and stabilize circulation in critically ill patients. Simultaneously, the volume status of the patient is very difficult to assess. Too little volume leads to inadequate organ perfusion followed by ischemia and organ failure. Too much volume may worsen heart failure and cause pulmonary and peripheral edema and contribute to further tissue injury and organ dysfunction. Although dynamic indices have been shown to be more accurate predictors of fluid responsiveness, this relevant and complex task is usually guided by static clinical variables and the specialist's interpretation due to the fact that the interpretation of dynamic parameters is not fully developed and that they are not universally available. This lack of understanding is partially because of the complex interaction with mechanical ventilation. The investigators hypothesize that knowing the distribution of ventilatory pressures will make it possible to index dynamic parameters to tidal volume and improve their predictive value concerning the volume status of the patient. In addition, it would be of interest to be able to predict fluid responsiveness in a non-invasive way, especially in critically ill patients. Up to now, continuous non-invasive cardiac output monitoring using Nexfin in critically ill patients has not been validated and also not tested for its ability to predict fluid responsiveness. The present research proposal evaluates the possibility and accuracy of the model flow analysis obtained by non-invasive finger arterial pressure measurements to determine fluid responsiveness using passive leg raising. It will also be compared to a more invasive method (that is currently used in the clinic) to assess its ability to measure absolute CO levels accurately. It may make it possible to assess fluid responsiveness in a non-invasive and patient friendly way.

Study Overview

• Status: Unknown
• Conditions: Fluid Responsiveness
• Intervention / Treatment: Other: ventilatory protocol; Other: Elastic band; Other: passive leg raising test

• Study Type: Interventional
• Enrollment (Anticipated): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Nijmegen, Netherlands
    • Recruiting
    • Radboud University Nijmegen Medical Centre
    • Contact: Peter Pickkers, MD, PhD; Email: p.pickkers@ic.umcn.nl
    • Principal Investigator: Peter Pickker, MD, PhD
    • Sub-Investigator: Benno Lansdorp, MSc.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: ADULT; OLDER_ADULT; CHILD
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Elective open heart surgery.

Exclusion Criteria:

• Significant cardiac arrhythmias, including atrial fibrillation.
• Hemodynamical instability, as defined by a variation in heart rate, blood pressure and cardiac output of more than 10% during the 15-min period before starting the protocol.
• Recent myocardial infarction (< 3 mnd, troponine > 50 ug/l).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: DIAGNOSTIC
• Allocation: NA
• Interventional Model: SINGLE_GROUP
• Masking: NONE

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Elective open heart surgery; Patients who had undergone elective open heart surgery	Other: ventilatory protocol; Ventilatory protocol for short period with four different tidal volumes (12 min); Other: Elastic band; Placement of an elastic band around thorax to reduce thorax compliance; Other: passive leg raising test; performing the passive leg raising test

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fluid responsiveness	pulse pressure variation (PPV), systolic pressure variation (SPV), stroke volume variation (SVV), pre-ejection period variation (dPEP)	30 minutes around fluid challenge

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pressure distribution in thorax due to mechanical ventilation	mechanical ventilation with 4 different tidal volumes and decreased chest compliance	30 minutes of varying tidal volumes
Dynamic indices in pressure support ventilation		30 minutes of pressure support
non invasive prediction of fluid responsiveness	pulse contour analysis of cardiac output with finger cuff combined with passive leg raising test	30 minutes around fluid challenge
pressure distribution and dynamic indices during spontaneous breathing		5 minutes of spontaneous breathing

Collaborators and Investigators

• Sponsor: Radboud University Medical Center
• Investigators: Principal Investigator: Benno Lansdorp, MSc., Radboud University Medical Center

Study record dates

Study Major Dates

• Study Start: January 1, 2010
• Primary Completion (ANTICIPATED): September 1, 2010
• Study Completion (ANTICIPATED): September 1, 2010

Study Registration Dates

• First Submitted: April 22, 2010
• First Submitted That Met QC Criteria: April 28, 2010
• First Posted (ESTIMATE): April 29, 2010

Study Record Updates

• Last Update Posted (ESTIMATE): August 31, 2010
• Last Update Submitted That Met QC Criteria: August 30, 2010
• Last Verified: January 1, 2010

More Information

Terms related to this study

• Keywords: mechanical ventilation; pulse pressure variation; fluid responsiveness; hemodynamic monitoring; fluid therapy
• Other Study ID Numbers: UMCN_IC_BL_01/2010