Weaning From Mechanical Ventilation
Conditions
Keywords
Diaphragmatic Tissue Doppler, Weaning, Mechanical ventilation
Brief summary
Weaning from mechanical ventilation is a critical issue and the diaphragmatic disfunction has been demonstrated to play an important role in extubation failure. the aim of present investigation is to evaluate diaphragmatic excursion velocity during in patients undergoing spontaneous breathing trial through tissue Doppler analysis in both inspiration and expiration.
Detailed description
Tobin Index (RSBI), which is the ratio between respiratory rate (RR) and tidal volume (VT), is one of the most used indices to predict weaning outcome. The diaphragm plays a key role in generating VT and, in the case of diaphragmatic dysfunction, inspiratory accessory muscles may contribute to support ventilation. If this occurs during a spontaneous breathing trial (SBT), it will probably result in delayed weaning, since the accessory muscles are more fatigable than the diaphragm. The diaphragmatic tissue Doppler imaging (TDI) is an ultrasonographic technique derived from ultrasound evaluation of heart's motility. Being a muscle doppler assessment, it can be easily used on the diaphragm to calculate the speed of muscles displacement that could be associated with patient's respiratory drive, as well as other derived index of muscle function. The aim of the study is to measure the variations of diaphragmatic displacement velocities before and during the spontaneous breathing trial, useful to check if the patient is ready to breathe spontaneously. An observational study will be performed. Patients who are ready to be weaned will be subjected to a spontaneous breathing test (Cpap 5), that consists of applying a positive end-expiratory pressure of 5 cm H2O for 20 minutes. A tissue Doppler evaluation will then be performed by analyzing the diaphragmatic displacement velocity during inspiration and expiration in the modality of ventilation which precedes the trial and during the SBT. Vital parameters will be monitored during the study. Mechanical ventilation length, incidence of tracheostomies, ICU and hospital recovery duration and hospital mortality will also be acquired.
Interventions
OTHERWeaning TDI
Patients will be subjected to a spontaneous breathing test (Cpap 5), that consists in applying a positive end-expiratory pressure of 5 cm H2O for 20 minutes. A tissue doppler evaluation will then be performed by analyzing the diaphragmatic displacement velocity during inspiration and expiration and calculating the speed of muscles displacement and other derived index of muscle function in the modality of ventilation which precedes the trial, during the SBT and after extubation.
Sponsors
Azienda Ospedaliero Universitaria Maggiore della Carita
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Single Group Assignment
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* mechanical invasive ventilation ≥ 24 h * readiness for extubation
Exclusion criteria
* refusal to grant consent * pregnancy * hemodynamic instability * difficult management of secretions * request for inotropy and/or vasoactive drugs at high doses
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Primary Outcome Measure - Change in diaphragmatic displacement velocity | through each trial completion, an average of 20 minutes | Inspiratory and expiratory diaphragmatic displacement velocity evaluated with tissue doppler during the assisted ventilation modality which preceded the trial, during the spontaneous breathing trial ( CPAP 5 ) and in spontaneous breathing. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Gas exchange - arterial carbon dioxide tension | through each trial completion, an average of 20 minutes | Arterial blood gases sample |
| Gas exchange - pH | through each trial completion, an average of 20 minutes | Arterial blood gases sample |
| Gas exchange - arterial oxygen tension | through each trial completion, an average of 20 min | Arterial blood gases sample |
| Diaphragmatic acceleration and deceleration | through each trial completion, an average of 20 minutes | Diaphragmatic acceleration and deceleration evaluated with tissue doppler during the assisted ventilation modality which preceded the trial, during the spontaneous breathing trial ( CPAP 5 ) and in spontaneous breathing. |
| Heart rate | through each trial completion, an average of 20 minutes | Heart Rate (HR) averages during each of the 3 ventilatory modes |
| Number of patients who experienced weaning failure | over 48 hours following extubation | the need for non invasive ventilation or re-intubation due to any cause |
| Blood Pressure | through each trial completion, an average of 20 minutes | Mean arterial Blood Pressure (BP) averages during each of the 3 ventilatory modes |
| Dyspnea level | through each trial completion, an average of 20 minutes | Dyspnea level will be evaluated through visual analogical scale ( VAS dyspnea). The dyspnea visual analog scale is represented by a 20 cm horizontal line. The ends are defined as the extreme limits of dyspnea from the left-lower end best, not at all breathless-to the right-upper end worst, extremely breathless. Subjects will be instructed to indicate on the line the point corresponding to their breathlessness perception. |
Countries
Italy
Outcome results
None listed