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

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.

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

Eligibility Criteria:
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