Ventilator-derived <i>Versus</i> Standard Rapid Shallow Breathing Index for Weaning Assessment: A Systematic Review

<h3>Background/Aim:</h3> The rapid shallow breathing index (RSBI) is widely used to assess readiness for liberation from mechanical ventilation. With advances in ventilator technology, RSBI is increasingly obtained directly from ventilator displays. However, differences in measurement conditions and ventilator settings may influence RSBI values and their clinical interpretation, particularly in relation to established cutoff thresholds. This systematic review aimed to evaluate differences between ventilator-derived and conventional RSBI measurements and their clinical implications. <h3>Materials and Methods:</h3> A systematic literature search was conducted in PubMed and Ovid for studies published up to February 24, 2026. Studies were included if they compared ventilator-derived RSBI with standard measurements in mechanically ventilated adult patients. Data on study design, measurement strategies, and outcomes were extracted and qualitatively synthesized. <h3>Results:</h3> A total of 11 prospective studies involving 824 patients were included. Most studies reported lower RSBI values under ventilatory support, particularly with pressure support ventilation (PSV) or continuous positive airway pressure (CPAP), compared with measurements obtained during unsupported spontaneous breathing. However, some studies reported higher or variable RSBI values depending on ventilator algorithms and measurement techniques. Despite these differences, moderate to good correlations were observed between ventilator-derived and conventional RSBI measurements. Additional factors, including trigger sensitivity and base flow, were found to influence RSBI values, whereas changes in FiO₂ had minimal impact. <h3>Conclusion:</h3> Ventilator-derived RSBI provides a practical alternative for assessing weaning readiness, but values may differ from conventional measurements depending on ventilatory support and measurement conditions. The traditional cutoff of 105 breaths/min/l remains appropriate for unsupported breathing, whereas lower thresholds may be required when RSBI is obtained from ventilators. Careful interpretation is necessary, and further studies are needed to establish standardized measurement approaches and optimal cutoff values.