Patient-ventilator Asynchrony in Conventional Ventilation Modes During Short-term Mechanical Ventilation After Cardiac Surgery

Universidade Federal de Pernambuco19 enrolled

Overview

This study evaluates the effects of VCV, PCV and PSV ventilatory modes during the immediate postoperative period on the variables resulting from regional and global pulmonary electrical impedance and diaphragmatic mobility, as well as perform ventilator synchrony analysis in PSV mode by mechanical ventilator. Half of the participants will receive VCV followed by PSV for weaning, while the other half will receive PCV followed by PSV for weaning.

In the immediate postoperative period of cardiac surgery, patients are found under mechanical ventilatory support. Commonly, they are ventilated in controlled and assisted-controlled volume (VCV) or pressure (PCV) modes, with weaning at pressure support (PSV). Systematic reviews indicate that there is no difference between the VCV and PCV ventilatory modes for some clinical outcomes or that the existing evidence is insufficient. The distribution of regional ventilation and diaphragmatic mobility can be measured from the use of electrical impedance tomography (EIT) and diaphragmatic ultrasonography (US) to clarify the physiological changes and / or mechanisms of adaptation of the organism submitted to controlled modes cycled at volume or at pressure and spontaneously flow cycled mode. Besides EIT and US measures, gasometric, hemodynamic and respiratory data will also be recorded. The statistical analysis will be considered α≤0.05 for a statistically significant difference.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

DIAGNOSTIC

Masking

DOUBLE

Enrollment

Conditions

Thoracic Surgery

Interventions

VCV+PSVDEVICE

invasive mechanical mechanical modes by volume cycling and by pressure support which the patients will be submitted to before weaning. Post-operative mechanical ventilation average time: 6 hours after ICU admission.

PCV+PSVDEVICE

invasive mechanical mechanical modes by pressure cycling and by pressure support which the patients will be submitted to before weaning. Post-operative mechanical ventilation average time: 6 hours after ICU admission.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * IMC 18.5-29.9 kg/m² * Two thoracic tubes (one mediastinal and one left-sided pleural) * under mechanical ventilation after surgery * submitted to intraoperative extracorporeal circulation Exclusion Criteria: * Over 2h of cardiopulmonary bypass * Over 12h of post-operative mechanical ventilation * Post-operative bleeding above 500 ml in the first hour or above 300 ml in the first two hours * History of special conditions (neuromuscular and chronic pulmonary disease, thoracic deformity, abdominal distension).

Locations (1)

Hospital Real Português de Beneficência em Pernambuco

Recife, Pernambuco, Brazil

Outcomes

Primary Outcomes

electrical impedance measures

impedance variation data recorded by a tomograph.

Time frame: 5 minutes of recording at each step of mechanical ventilation progression before extubation.

Secondary Outcomes

arterial gas blood analysis data

measures of pH, PaCO2 (mmHg), PaO2 (mmHg), PaO2/FiO2

Time frame: up to 12h, following routine care while patients are mechanically ventilated

patient-ventilator synchrony

events of discomfort between patient and ventilator: ineffective efforts and auto-triggering. Expressed in present or ausent.

Time frame: 5 minutes of recording at each step of mechanical ventilation progression before extubation

Data from ClinicalTrials.gov

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