Respiratory Mechanics and Patient-ventilator Asynchrony Index in Patients With Invasive Mechanical Ventilation

Study Overview
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Brief Summary
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The objective of the study is to estimate the incidence of asynchrony and to assess its relationship with respiratory mechanics. This will be a prospective cohort study, including patients under invasive mechanical ventilation. Within 48h post intubation, the investigators will record the values of intrinsic positive end-expiratory pressure, pulmonary compliance and resistance. Participants will be followed up from intubation to mechanical ventilation liberation. The investigators will register clinical signs of asynchrony and record ventilator waveforms continuously and quantify patient-ventilator asynchrony. The investigators will calculate the total asynchrony index (AI) and of each asynchrony type (ineffective triggering, double triggering, auto triggering, short cycling and prolonged cycling). Participants will be followed up until hospital discharge.

Detailed Description
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Patient-ventilator asynchrony is common in patients under invasive mechanical ventilation, present between 10 and 80% of all respiratory cycles, and is associated with adverse clinical outcomes, such as delay in the weaning process, increased complications of mechanical ventilation, with possible impact on survival. The objective of this study is to estimate the incidence of asynchrony and to assess its relationship with respiratory mechanics. This will be a prospective cohort study, including all patients under invasive mechanical ventilation admitted at Respiratory ICU at Hospital das Clínicas da Faculdade de Medicina da Universidade de Sao Paulo (USP), during the study period. Within 48h post intubation, the investigators will record the values of intrinsic positive end-expiratory pressure, pulmonary compliance and resistance. Participants will be followed up from intubation to mechanical ventilation liberation. The investigators will register clinical signs of asynchrony and record ventilator waveforms continuously. The ventilator waveforms will be captured directly from ventilator and processed by dedicated software, without direct contact with patients. Later, ventilator waveforms will be analyzed to quantify patient-ventilator asynchrony. The investigators will calculate the total asynchrony index (AI) and of each asynchrony type (ineffective triggering, double triggering, auto triggering, short cycling and prolonged cycling). Participants will be followed up until hospital discharge, and the investigators will record duration of mechanical ventilation, the use of non-invasive ventilation post-extubation, reintubation, tracheostomy, ICU and hospital length of stay and survival. With this project, the investigators will estimate the incidence and magnitude of patient-ventilator asynchrony and its association with clinical outcomes

Official Title
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Respiratory Mechanics and Patient-ventilator Asynchrony Index in Patients With Invasive Mechanical Ventilation

Conditions
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Respiratory Insufficiency

Intervention / Treatment
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* Other: mechanical ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Recent mechanical ventilation (less than 72 hours) Expectation of mechanical ventilation for more than 24 hours Age ≥ 18 years old Exclusion Criteria: High flow Bronchopleural fistula Thoracic or abdominal deformities that could compromise the accuracy of respiratory mechanics measurement Impossibility to measure respiratory mechanics Tracheostomy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Mechanical ventilation<br>Patients under mechanical ventilation for more than 24h | Other: mechanical ventilation<br>* we will measure static resistance, compliance and intrinsic positive end-expiratory pressure (PEEP) and other variables as risk factors for asynchrony occurrence<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| asynchrony index | asynchrony index will be calculated as the number of major asynchrony events divided by total number of respiratory cycles | from study inclusion until the date of extubation or date of death from any cause, whichever comes first, up to 28 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical signs of patient-ventilator asynchrony | a standardized questionnaire will be used to evaluate the presence of clinically significant patient-ventilator asynchrony. Trained investigators will observe participant´s breathing pattern and other clinical signs of patient-ventilator asynchrony and score each item as absent (0) or present (1). Then, they will visual inspection of ventilator waveforms on the ventilator screen for a 5 minute observation period, looking for missed efforts, double triggering, auto-triggering, cycling delay and premature cycling, as previously defined. If they observe more than 1 asynchrony event for every 10 respiratory cycles, they will rate this item as present (1), otherwise, they will rate it as absent (0). | daily, from study inclusion until the date of extubation or date of death from any cause, whichever comes first, up to 28 days | 
| ventilation free-days | number of days alive and off the ventilator up to day 28 | 28 days | 
| tracheostomy rate | performance of surgical or bronchoscopy-guided tracheotomy | up to 90 days | 
| Survival rate | survival from intubation up to 90 days | at 28 and 90 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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respiratory mechanics, Respiratory Insufficiency, artificial, ventilation