Introduction:

By measuring diaphragmatic thickening and thickness change in expiration and inspiration, it can be used as a measure to predict the success or failure of extubation. The fraction of diaphragmatic thickness (FDT) was assessed by ultrasound in intensive care patients.

Methods:

65 patients with invasive mechanical ventilation were recruited prospectively at the Department of Critical Care Medicine ABC Medical Center. The FDT was measured in the area of apposition of the diaphragm to the chest in both hemithorax, using an ultrasound transducer of 4 MHz. Patients underwent a spontaneous breathing trial (SBT) when they met all the following criteria are: FiO2 < 50%, PEEP ≤ 5 cmH2O, PaO2/FiO2 > 200, respiratory rate < 30 per minute, absence of fever, neurologically alert and without hemodynamic vasopressor support. The percentage change in FDT was calculated between the end of expiration and end of inspiration in patients with invasive mechanical ventilation with pressure support ventilation mode, all patients with ventilatory progression purposes extubation. A successful extubation was defined as spontaneous breathing > 48 hours without ventilatory support after removal of the endotracheal tube.

Results:

We included data obtained from 65 patients, 23 (35.4%) women and 42 (64.6%) men, mean Body Mass Index (BMI) of 25.83 (SD ± 4.19). The frequency of extubation failure was 21.5%, and mortality 24.6%. The variables associated with failure were cut-off values of DTF right 25.9%, DTF 23.1% left. Time of mechanical ventilation in days with a median of 4 (RIQ 3-6) versus 8.5 (RIQ 7-11), p <0.001 and RSBI with 68.2 ± 9.6 versus 53.9 ± 11.1, p < 0.001. The variables obtained from USG measurements were as follows: right thickness at end expiration (RTEEx) 0.28 ± .05 cm, right thickness at end inspiration (RTEIs) 0.21 ± .05 cm, right diaphragmal thickness (RDTi) 0.76 ± 0.11 cm, right diaphragmatic fraction index (RDFi) 23.1 ± 10.7%.

The positive predictive value and negative predictive value were 92 and 64%, respectively. The area under the ROC curve was 0.79 for DTF.

Conclusions:

Diaphragmatic thickness measurements by ultrasound can be a useful parameter to predict the success or failure of extubation during ventilatory progression in patients with invasive mechanical ventilation. Rapid shallow breathing index (RSBI) with a mean of 57.0 ± 12.3 points. This study demonstrates that there is no relation between failure to extubation with COPD, BMI and age. Extubation is a joint procedure and the more parameters for extubation, the lower the risk of failure.

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