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Effects of Inspiratory Flow Waveforms on Preload

This study has been completed.
Information provided by (Responsible Party):
Hajjej Zied, Military Hospital of Tunis Identifier:
First received: June 26, 2013
Last updated: November 7, 2016
Last verified: November 2016
The clinical usefulness of inspiratory flow pattern manipulation during mechanical ventilation remains unclear. The aim of this study was to investigate the effects of different inspiratory flow waveforms, i.e. constant and decelerating, on cardiac preload in mechanically ventilated patients assessed by arterial pulse pressure variation (PPV) and inferior vena cava distensibility.

Condition Intervention
Cardiac Output, Low
Device: varying inspiratory flow waveforms

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Supportive Care
Official Title: Arterial Pulse Pressure Variation and Inferior Vena Cava Distensibility Affected by Inspiratory Flow Waveforms in Mechanically Ventilated Patients: Time for a Change

Resource links provided by NLM:

Further study details as provided by Hajjej Zied, Military Hospital of Tunis:

Primary Outcome Measures:
  • change in pulse pressure variation (ΔPP) and distensibility index of the inferior vena cava (dIVC)when varying inspiratory flow waveforms [ Time Frame: 2h ]
    Each inspiratory flow waveform was maintained for 30 min with 60 minutes washout period

Enrollment: 60
Study Start Date: May 2013
Study Completion Date: August 2013
Primary Completion Date: July 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
mechanically ventilated patients

patients admitted to a 18-bed medical surgical intensive care unit of the military hospital of Tunisia and were mechanically ventilated fully adapted to their ventilator and in sinus rhythm.

intervention:varying inspiratory flow waveforms

Device: varying inspiratory flow waveforms
inspiratory flow waveform was changed, in a randomized sequence using a computer ,to one of the following modalities: 1) constant inspiratory flow; 2) decelerating inspiratory flow Each inspiratory flow waveform was maintained for 30 min. During the last 5 min of this period the physiological signals were collected and measures were performed.

Detailed Description:
During mechanical ventilation the lungs can be inflated with different pressure and flow waveforms. Originally the piston-driven mechanical ventilators generated a quasi-sinusoidal flow waveform, whereas the newer electronically controlled ventilators can also produce constant and decelerating waveforms. According to several theoretical,animal and clinical studies,the inspiratory flow waveform affects the distribution of the inspired gas as well as respiratory mechanics and gas exchange. However, other studies failed to show any significant effect.But there is no study interested to the effects of inspiratory flow waveforms on cardiac preload. Thus, the clinical usefulness of inspiratory flow pattern manipulation remains unclear, though the capacity for selection of different inspiratory flow waveforms is provided by most modern, microprocessor-equipped ventilators. Therefore, the purpose of this study was to compare the effects of flow patterns (sinusoidal, constant and decelerating) on dynamic measurements of cardiac preload dependence such as arterial pulse pressure variation (ΔPP) and distensibility index of the inferior vena cava (dIVC).

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

Inclusion Criteria:

  • mechanical ventilation
  • Volume AssistControl Ventilation
  • sinus rhythm

Exclusion Criteria:

  • pressure mode
  • arrhythmia
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Please refer to this study by its identifier: NCT01892696

Military hospital of tunis
Tunis, Mont Fleury, Tunisia, 1008
Sponsors and Collaborators
Military Hospital of Tunis
Principal Investigator: zied hajjej, Dr Military Hospital of Tunis
  More Information

Responsible Party: Hajjej Zied, Dr, Military Hospital of Tunis Identifier: NCT01892696     History of Changes
Other Study ID Numbers: CvDVPPIVC
CvD1977 ( Other Identifier: Military Hospital of Tunis )
Study First Received: June 26, 2013
Last Updated: November 7, 2016

Keywords provided by Hajjej Zied, Military Hospital of Tunis:
inspiratory flow pattern
mechanical ventilation
cardiac preload
arterial pulse pressure variation
inferior vena cava collapsibility

Additional relevant MeSH terms:
Respiratory Aspiration
Cardiac Output, Low
Respiration Disorders
Respiratory Tract Diseases
Pathologic Processes
Heart Diseases
Cardiovascular Diseases
Signs and Symptoms processed this record on May 25, 2017