Acceptable Range of Inspiratory Effort During Mechanical Ventilation

Completed

• Conditions: Elective Cardiac Surgery

• Registration Number: NCT02838524
• Lead Sponsor: Unity Health Toronto

Brief Summary

Partially assisted mechanical ventilation is ideally titrated to maintain adequate inspiratory muscle activity (i.e. preventing disuse atrophy) while avoiding excessive (i.e. fatiguing) inspiratory loads. The advent of ventilator modes enabling flow and pressure assistance in proportion to patient inspiratory effort (i.e. Proportional Assist Ventilation (PAV), Neurally-Adjusted Ventilator Assist (NAVA)) permit careful titration of ventilatory support to achieve desired levels of patient inspiratory effort. However, data on the acceptable range of values for inspiratory effort and respiratory muscle load-capacity balance during mechanical ventilation are currently very limited. Such data are critical to inform a physiologically sound evidence-based approach to titrating partially-assisted ventilatory support. This study is designed to ascertain a physiologically acceptable range of inspiratory effort in mechanically ventilated patients. The study protocol includes measurements of the respiratory system during spontaneous breathing as well as evaluating the diaphragm in real-time with the use of ultrasonography. The experimental design outlined in the present study is predicated on the assumption that the range of values for inspiratory effort and load-capacity balance observed in patients who are successfully weaned from mechanical ventilation represent the safe and appropriate range of target values.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2016-07-15
• Study First Submitted QC: 2016-07-15
• Study First Posted: 2016-07-20
• Study Start: 2016-09
• Primary Completion: 2018-03-01
• Study Completion: 2018-03-01
• Status Verified: 2018-04
• Last Update Submitted: 2018-04-11
• Last Update Posted: 2018-04-12

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 43

Inclusion Criteria

• Adult patients (>17) receiving invasive mechanical ventilation following elective cardiac surgery who will undergo a trial of spontaneous breathing

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Exclusion Criteria

• Pregnant women
• Decompensated cardiac insufficiency or acute coronary syndrome
• Severe COPD
• Contraindications to esophageal catheter placement, namely known esophageal varices

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Maximal inspiratory effort generated by a patient	During 10-15 minutes of the spontaneous breathing trial

Secondary Outcome Measures

Name	Time	Method
Muscular load-capacity balance measured by the tension-time index of the respiratory muscles	15 minutes
Diaphragmatic thickening fraction	15 minutes
Airway occlusion pressure (P0.1) performed manually and as measured by the ventilator	15 minutes
Success or failure of the spontaneous breathing trial	15 minutes
Diaphragmatic excursion	15 minutes

Trial Locations

Locations (1)

St. Michael's Hospital; 🇨🇦 Toronto, Ontario, Canada