Ventilator Hyperinflation and Hemodynamics

Centro Universitário Augusto Motta17 enrolled

Overview

Ventilator hyperinflation (VHI) has been shown to be effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated patients; however, the literature is scarce concerning its safety and adverse effects. Thus, the aim of this study is to compare the hemodynamic repercussions of VHI in volume-controlled mode. In a randomized, controlled and crossover design, 24 mechanically ventilated patients will undergo 2 modes of ventilator hyperinflation (with and without an inspiratory pause) and a control intervention. Cardiac output, cardiac index, mean arterial pressure, pulmonary vascular resistance, systolic volume and other hemodynamic variables will be recorded during the interventions.

Background: ventilator hyperinflation (VHI) has been shown to be effective in improving respiratory mechanics, secretion removal, and gas exchange in mechanically ventilated patients; however, the literature is scarce concerning its safety and adverse effects. Thus, the aim of this study is to compare the hemodynamic repercussions of VHI in volume-controlled mode. Methods: in a randomized, controlled and crossover design, 24 mechanically ventilated patients will undergo 2 modes of ventilator hyperinflation (with and without an inspiratory pause of 2 seconds) and a control intervention. For the VHI interventions, the inspiratory flow will be set at 20 Lpm, and tidal volume will be increased until a peak pressure of 40cmH2O is achieved. During the control intervention, the patients will remain in volume-control ventilation with an inspiratory flow = 60Lpm and tidal volume = 6mL/IBW. The interval between interventions (washout) will be of 10 minutes or more, according to the time needed to recover the cardiac index to baseline values (maximum difference of 10%). Cardiac output, cardiac index, mean arterial pressure, pulmonary vascular resistance, systolic volume and other hemodynamic variables will be recorded during the interventions by using impedance cardiography.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

Interventions

Baseline Mechanical VentilationDEVICE

The subjects will be kept in Volume Control Continuous Mandatory Ventilation (VC-CMV).

VHI With Inspiratory PauseDEVICE

Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV) with an inspiratory pause.

VHI Without Inspiratory PauseDEVICE

Application of a ventilator hyperinflation intervention with Volume Control Continuous Mandatory Ventilation (VC-CMV) without an inspiratory pause.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 90 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients under mechanical ventilation for more than 48h Exclusion Criteria: * mucus hypersecretion (defined as the need for suctioning \< 2-h intervals), * absence of respiratory drive, * atelectasis, * severe bronchospasm, * positive end expiratory pressure \> 10cmH2O, * PaO2-FiO2 relationship \< 150, * mean arterial pressure \< 60mmHg, * inotrope requirement equivalent to \>15 ml/h total of adrenaline and noradrenalin, * intracranial pressure \> 20mmHg

Outcomes

Primary Outcomes

Change in Cardiac Output

Estimation of cardiac output variation using thoracic bioimpedance

Time frame: Baseline (before) and 10 minutes after the onset of VHI modesBasel

Secondary Outcomes

Change in Cardiac Index

Estimation of cardiac index variation using thoracic bioimpedance

Time frame: Baseline (before) and 10 minutes after the onset of VHI modes

Change in Vascular pulmonary resistance

Estimation of vascular pulmonary resistance variation using thoracic bioimpedance

Time frame: Baseline (before) and 10 minutes after the onset of VHI modes

Change in Systolic Volume

Estimation of systolic volume variation using thoracic bioimpedance

Time frame: Baseline (before) and 10 minutes after the onset of VHI modes

Change in Mean Arterial Pressure

Recording of mean arterial pressure variation using an automatic noninvasive device

Time frame: Baseline (before) and 10 minutes after the onset of VHI modes

Change in Cardiac Output II

Estimation of cardiac output variation using thoracic bioimpedance