How Mechanical Ventilation Measurement, Cutoff and Duration Affect Rapid Shallow Breathing Index Accuracy: A Randomized Trial

Clinical utility of rapid shallow breathing index in predicting successful weaning: secondary analysis of the COBRE-US trial

OBJECTIVE

To assess the predictive capacity of the Rapid Shallow Breathing Index (RSBI) for success in spontaneous breathing trials (SBT) and extubation in critically ill patients. We evaluated the association between RSBI, duration of mechanical ventilation, and ventilator-free time at 28 days.

DESIGN

Prospective multicenter observational study. Secondary analysis of the COBRE-US study.

SETTING

Intensive care unit (ICU).

PATIENTS OR PARTICIPANTS

367 patients in the ICU receiving invasive mechanical ventilation.

INTERVENTIONS

Assessment of RSBI at the end of SBT.

MAIN VARIABLES OF INTEREST

RSBI, SBT, duration of mechanical ventilation, and ventilator-free time at 28 days were evaluated.

RESULTS

367 patients in the ICU under invasive mechanical ventilation were evaluated, of whom 59.7% were male with a median age of 61 years (IQR: 49-72). A total of 456 SBT were conducted with a success rate of 76.5%. RSBI had a ROC-curve of 0.53 for SBT success and a ROC-curve of 0.48 for extubation. The Spearman correlation coefficient between RSBI and duration of ventilation was 0.117 (p = 0.026), while for ventilator-free time at 28 days, it was -0.116 (p = 0.028).

CONCLUSIONS

RSBI was not associated with success in SBT or extubation, regardless of the cutoff point used. Correlation analyses showed weak associations between RSBI and both the duration of ventilation and ventilator-free time at 28 days.

Rapid shallow breathing index predicting extubation outcomes: A systematic review and meta-analysis

OBJECTIVE

This meta-analysis aimed to assess the predictive value of the rapid shallow breathing index for extubation outcomes.

METHODOLOGY

We conducted a systematic review of literature (inception to March 2023) and a meta-analysis. Statistical analysis was performed using Meta-Disc 1.4 software, RevMan 5.4 software and Stata 14.0 software to evaluate the predictive value of RSBI for extubation outcomes.

RESULTS

A total of 1,987 studies were retrieved, and after applying the inclusion criteria, 79 studies were included in the final analysis, involving 13,170 patients undergoing mechanical ventilation. The random-effects model was employed for statistical analysis. The summary receiver operating characteristic curves (SROC) area under the curve (AUC) was 0.8144. The pooled sensitivity was 0.60 (95% CI: 0.59, 0.61), the pooled specificity was 0.68 (95% CI: 0.66, 0.70).

CONCLUSIONS

The Rapid Shallow Breathing Index demonstrated moderate accuracy, poor pooled sensitivity and specificity in predicting successful extubation, however the study does not present adequate data to support or reject the use of this tool as a single parameter that predicts extubation outcome. Future studies should explore the combination of The Rapid Shallow Breathing Index with other indicators and clinical experience to improve the success rate of extubation and reduce the risk of extubation failure.

IMPLICATIONS FOR CLINICAL PRACTICE

Premature and delayed extubation in mechanically ventilated patients can have a negative impact on prognosis and prolong hospital stay. The Rapid Shallow Breathing Index is a simple, cost-effective, and easily monitored objective evaluation index, which can be used to predict the outcome of extubation, especially in primary hospitals. Our study comprehensively evaluated the value of this tool in predicting extubation outcomes, which can help clinicians combine subjective experience with objective indicators to improve the accuracy of extubation time decisions.

Comparison of different methods of obtaining the rapid shallow breathing index

OBJECTIVE

To compare the Rapid Shallow Breathing Index (RSBI) obtained by the ventilometer and from mechanical ventilation parameters.

METHODS

Randomized crossover trial, including 33 intubated patients, on mechanical ventilation for at least 24 hours, undergoing spontaneous breathing test. Patients were submitted to the measurement of RSBI by four methods: disconnected from the ventilator through the ventilometer; in Pressure Support Ventilation (PSV) mode at a pressure of 7.ßcm H2O; in Continuous Positive Airway Pressure (CPAP) mode at a pressure of 5.ßcmH2O with flow trigger; in CPAP mode at a pressure of 5.ßcmH2O with pressure trigger.

RESULTS

No significant difference was detected between the RSBI obtained by the ventilometer and in the CPAP mode with flow and pressure triggers, however, in the PSV mode, the values were lower than in the other measurements (p.ß<.ß0.001). By selecting patients from the sample with higher RSBI (... 80 cycles.min-1.L-1), the value of the index obtained by the ventilometer was higher than that obtained in the three options of ventilation methods.

CONCLUSION

The RSBI obtained in the CPAP mode at a pressure of 5.ßcmH2O, in both triggers types, did not differ from that measured by the ventilometer; it is, therefore, an alternative when obtaining it from mechanical ventilation parameters is necessary. However, in the presence of borderline values, the RSBI measured by ventilometer is recommended, as in this method the values are significantly higher than in the three ventilation modalities investigated.

The Usefulness of the Rapid Shallow Breathing Index in Predicting Successful Extubation: A Systematic Review and Meta-analysis

BACKGROUND

Clinicians use several measures to ascertain whether individual patients will tolerate liberation from mechanical ventilation, including the rapid shallow breathing index (RSBI).

RESEARCH QUESTION

Given varied use of different thresholds, patient populations, and measurement characteristics, how well does RSBI predict successful extubation?

STUDY DESIGN AND METHODS

We searched six databases from inception through September 2019 and selected studies reporting the accuracy of RSBI in the prediction of successful extubation. We extracted study data and assessed quality independently and in duplicate.

RESULTS

We included 48 studies involving RSBI measurements of 10,946 patients. Pooled sensitivity for RSBI of < 105 in predicting extubation success was moderate (0.83 [95% CI, 0.78-0.87], moderate certainty), whereas specificity was poor (0.58 [95% CI, 0.49-0.66], moderate certainty) with diagnostic ORs (DORs) of 5.91 (95% CI, 4.09-8.52). RSBI thresholds of < 80 or 80 to 105 yielded similar sensitivity, specificity, and DOR. These findings were consistent across multiple subgroup analyses reflecting different patient characteristics and operational differences in RSBI measurement.

INTERPRETATION

As a stand-alone test, the RSBI has moderate sensitivity and poor specificity for predicting extubation success. Future research should evaluate its role as a permissive criterion to undergo a spontaneous breathing trial (SBT) for patients who are at intermediate pretest probability of passing an SBT.

TRIAL REGISTRY

PROSPERO; No.: CRD42020149196; URL: www.crd.york.ac.uk/prospero/.