Effects of Inspiratory Flow Waveforms on Preload

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.

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Key information

Conditions

Cardiac Output, Low Cardiovascular Diseases Heart Diseases Pathological Conditions, Signs and Symptoms Signs and Symptoms

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Military hospital of tunis

Tunis, Mont Fleury, 1008, Tunisia

About this study

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).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

mechanical ventilation
Volume AssistControl Ventilation
sinus rhythm

Exclusion criteria

pressure mode
arrhythmia

Treatment and study plan

varying inspiratory flow waveforms

Device

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.

Primary outcomes

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

Sponsors and collaborators

Lead sponsor

Military Hospital of Tunis

Other

Registry information

Official study title

Arterial Pulse Pressure Variation and Inferior Vena Cava Distensibility Affected by Inspiratory Flow Waveforms in Mechanically Ventilated Patients: Time for a Change

Important dates

Study start: 2013
Primary completion: 2013
Study completion: 2013
First posted: Jul 4, 2013
Registry last updated: Nov 9, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed