Use of diaphragm thickening fraction combined with rapid shallow breathing index for predicting success of weaning from mechanical ventilator in medical patients

Abstract

BackgroundWeaning failure is a crucial hindrance in critically ill patients. Rapid shallow breathing index (RSBI), a well-known weaning index, has some limitations in predicting weaning outcomes. A new weaning index using point-of-care ultrasound with diaphragmic thickening fraction (DTF) has potential benefits for improving weaning success. The aim of this study was to evaluate the efficacy of a combination of DTF and RSBI for predicting successful weaning compared to RSBI alone.MethodsThis prospective study enrolled patients from the medical intensive care unit or ward who were using mechanical ventilation and readied for weaning. Patients underwent a spontaneous breathing trial (SBT) for 1 h, and then, both hemi-diaphragms were visualized in the zone of apposition using a 10-MHz linear probe. Diaphragm thickness was recorded at the end of inspiration and expiration which supposed the lung volume equal to total lung capacity (TLC) and residual volume (RV), respectively, and the DTF was calculated as a percentage from this formula: thickness at TLC minus thickness at RV divided by thickness at RV. In addition, RSBI was calculated at 1 min after SBT. Weaning failure was defined as the inability to maintain spontaneous breathing within 48 h.ResultsOf the 34 patients enrolled, the mean (± SD) age was 66.5 (± 13.5) years. There were 25 patients with weaning success, 9 patients in the weaning failure group. The receiver operating characteristic curves of right and left DTF and the RSBI for the prediction of successful weaning were 0.951, 0.700, and 0.709, respectively. The most accurate cutoff value for prediction of successful weaning was right DTF ≥ 26% (sensitivity of 96%, specificity of 68%, positive predictive value of 89%, negative predictive value of 86%). The combination of right DTF ≥ 26% and RSBI ≤ 105 increased specificity to 78% but slightly decreased sensitivity to 92%. Intra-observer correlation increased sharply to almost 0.9 in the first ten patients and slightly increased after that.ConclusionsPoint-of-care ultrasound to assess diaphragm function has an excellent learning curve and helps physicians determine weaning readiness in critically ill patients. The combination of right DTF and RSBI greatly improved the accuracy for prediction of successful weaning compared to RSBI alone.Trial registrationThai Clinical Trials Registry, TCTR20171025001. Retrospectively registered on October 23, 2017.

Diaphragmatic rapid shallow breathing index for predicting weaning outcome from mechanical ventilation: Comparison with traditional rapid shallow breathing index

“…However, it has some limitations in predicting weaning outcomes [5]. Several previous studies have defined different sensitivities and specificities for RSBI less than 105 to predict weaning success which may lead to errors in predicting successful weaning [6][7][8].…”

Diaphragm shear modulus reflects transdiaphragmatic pressure during isovolumetric inspiratory efforts and ventilation against inspiratory loading

“…Diaphragm SWE appears to have a strong potential for direct, noninvasive, and specific assessment of diaphragm effort. SMdi coupled with functional respiratory investigations may help to detect diaphragm dysfunction (25). Although feasibility of diaphragm SWE in the left zone of apposition (and other approaches) remain to be investigated, it might be particularly useful for detecting diaphragm hemi-paralysis.…”

Role of lung ultrasound in weaning from mechanical ventilation in postoperative neurosurgical ICU patients

“…Another study done by Pirompanich and Romsaiyut concluded that DTF ≥ 26% combined with RSBI ≤ 105 increased the rate of successful weaning compared to RSBI alone. 17 Our study found that DTF of more than 40% was associated with successful weaning. Establishment of MV and further therapeutic interventions were done in patients with DTFS ≤ 25%.…”