The Relationship Between Trans-diaphragmatic Pressure and Diaphragmatic Contraction
Trial Parameters
Brief Summary
Through this study the investigators aim to clarify the relationship between trans-diaphragmatic pressure and various parameters of the diaphragmatic contraction evaluated by ultrasound. Moreover, a lung ultrasound exam will be performed at the end of spontaneous breathing, resistive breathing and maximal inspiratory pressure maneuver (MIP) in order to assess with the use of B-lines for extravascular lung water (EVLW). The following parameters will be studied: esophageal pressure, gastric pressure, diaphragm thickness at peak inspiration (Tdi,pi), diaphragm thickness at end expiration (Tdi,ee), diaphragm thickening (Tdi,pi - Tdi,ee), diaphragm thickness fraction \[TFdi=(Tdi,pi - Tdi,ee)/Tdi,ee\], diaphragm excursion (Dec), Maximal Inspiratory pressure (M.I.P), Pressure-Time product of the esophageal pressure (PΤPes),Tension Time Diaphragm Index (T.T.Di) and the rapid shallow breathing index (R.S.B.I.). These measurements will be made in two phases.Firstly, during the spontaneous breathing trial and secondly during spontaneous breathing through an airway of reduced diameter.Furthermore, during the M.I.P. test the aforementioned ultrasound parameters will be measured. The aim of this study is to discover new means of a successful prediction of weaning in the first 48 hours following extubation.
Eligibility Criteria
Inclusion Criteria: Patients meeting the following standards. * Respiratory Criteria * PaO2≥ 60mmHg with Fraction of Inspired Oxygen (FiO2) ≤ 40-50% \& Positive End Expiratory Pressure (PEEP) ≤ 5-8 cm H2O * PaCO2 normal or at the level of reference (allowed hypercapnia is allowed) * Patient is able to start ventilatory effort * Cardiovascular Criteria * Absence of myocardial ischemia * Heart Rate ≤140 bpm * Arterial Pressure normal without vasoconstriction or with minimum vasoconstriction support * Adequate level of consciousness o Glasgow Coma Scale (GCS ≥ 13) * Absence of other reversible comorbidities * Afebrile Patient * Without important electrolyte disorders Exclusion Criteria: * Obese patients with B.M.I. \>35 * pregnant women * patients \<18 years old