Diaphragmatic Rapid Shallow Breathing Index for Predicting Weaning Outcome From Mechanical Ventilation
Condition: Weaning Failure
MeSH terms: Respiratory Aspiration
Study type: Interventional

Summary: 
      Predicting successful discontinuation from mechanical ventilation has been a focus of
      interest to all critical care physicians . Various weaning indices have been investigated to
      optimize the weaning process. Among them, the rapid shallow breathing index (RSBI) has gained
      wide use but it have different sensitivities and specificities. By substituting tidal volume
      (VT) with diaphragmatic displacement (DD) in the calculation of RSBI a new index (the
      diaphragmatic rapid shallow breathing index DRSBI) was proposed and it was independently
      associated with weaning failure and its accuracy for predicting weaning outcome is expected
      to be superior to the traditional RSBI.
    

Detailed description: 
      The rapid shallow breathing index (RSBI), calculated from respiratory rate divided by tidal
      volume (RR/VT), is a well-known weaning index and one of the most clinical indices used to
      predict weaning outcome. However, it has some limitations in predicting weaning outcomes.
      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.

      On the other hand, Weaning failure is likely to occur if there is an imbalance between the
      load on the inspiratory muscles and their neuromuscular capacity, the imbalance between the
      mechanical load imposed on the diaphragm which is the major muscle of inspiration and its
      ability to cope with it. Therefore, evaluating the function of diaphragm before any weaning
      trial could be useful in predicting weaning outcome.

      Bedside ultrasonography is an easy, fast, noninvasive, and accurate maneuver for evaluating
      diaphragmatic function. Diaphragmatic displacement (DD) reflecting the ability of diaphragm
      to produce force and subsequently tidal volume during inspiration and defined as displacement
      of less than 10 mm has been found to be a predictor of weaning failure among patients in
      medical ICUs.

      Spadaro et al. proposed substituting VT with DD in the RSBI, and calculating diaphragmatic
      RSBI (DRSBI) would result in a more accurate predictive index than the traditional RSBI.
    

Intervention name(s): Diaphragm ultrasound
Intervention type(s): Other
Intervention description(s): In the semi-sitting position ultrasonography for diaphragmatic displacement was performed by the same intensivist. Diaphragmatic movement was evaluated by using 2 to 5 MHz US probe (Sonosite M-Turbo machine). The right hemidiaphragm was examined by two-dimensional (2D) and M-mode to record diaphragm displacement.in M-mode, the diaphragmatic displacement (cm) was measured and then DRSBI was calculated by respiratory rate (RR)/ diaphragmatic displacement (DD) (in mm)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Care Provider)
Primary purpose: Other