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.

Fatores associados à falha de extubação em unidade de terapia intensiva: estudo de caso-controle

Resumo Objetivo: investigar os fatores associados à falha de extubação de pacientes na unidade de terapia intensiva. Método: caso-controle não pareado, longitudinal, retrospectivo e quantitativo com a participação de 480 pacientes por meio de parâmetros clínicos para desmame ventilatório. Dados analisados por: Teste Exato de Fisher ou o teste Qui-quadrado; teste t de Student bicaudal não pareado; e teste de Mann-Whitney. Admitiram-se significantes valores de P menores ou iguais a 0,05. Resultados: dos pacientes, 415 (86,5%) tiveram sucesso e 65 (13,5%) falharam. Grupo sucesso: balanço hídrico mais negativo, APACHE II em 20 (14-25), tosse fraca em 58 (13,9%). Grupo falha: balanço hídrico mais positivo, APACHE II em 23 (19-29), tosse fraca em 31 (47,7 %), quantidade abundante de secreção pulmonar em 47,7 %. Conclusão: o balanço hídrico positivo e a presença de tosse ineficiente ou incapacidade de higienizar a via aérea foram preditores de falhas de extubação.

Factors associated with extubation failure in an intensive care unit: a case-control study

Abstract Objective: to investigate the factors associated with extubation failure of patients in the intensive care unit. Method: unpaired, longitudinal, retrospective and quantitative case-control with the participation of 480 patients through clinical parameters for ventilator weaning. Data were analyzed by: Fisher’s exact test or the chi-square test; unpaired two-tailed Student’s t test; and Mann-Whitney test. Significant P values lower than or equal to 0.05 were admitted. Results: of the patients, 415 (86.5%) were successful and 65 (13.5%) failed. Success group: the most negative fluid balance, APACHE II in 20 (14-25), weak cough in 58 (13.9%). Failure group: the most positive fluid balance, APACHE II in 23 (19-29), weak cough in 31 (47.7%), abundant amount of pulmonary secretions in 47.7%. Conclusion: positive fluid balance and the presence of inefficient cough or inability to clear the airway were predictors of extubation failure.

Factores asociados al fracaso de la extubación en unidad de cuidados intensivos: estudio de caso y control

Resumen Objetivo: investigar los factores asociados al fracaso de la extubación de pacientes en la unidad de cuidados intensivos. Método: caso y control no apareado, longitudinal, retrospectivo y cuantitativo con la participación de 480 pacientes mediante parámetros clínicos para el destete de la ventilación. Datos analizados por: Prueba Exacta de Fisher o prueba de Chi-cuadrado; prueba t de Student de dos colas para datos no apareados; y prueba de Mann-Whitney. Se admitieron valores de P significativos menores o iguales a 0,05. Resultados: de los pacientes, 415 (86,5%) tuvieron éxito y 65 (13,5%) fracasaron. Grupo de éxito: balance hídrico más negativo, APACHE II en 20 (14-25), tos débil en 58 (13,9%). Grupo de fracaso: balance de líquidos más positivo, APACHE II en 23 (19-29), tos débil en 31 (47,7%), abundante cantidad de secreciones pulmonares en 47,7%. Conclusión: el balance hídrico positivo y la presencia de tos ineficaz o incapacidad para higienizar la vía aérea fueron predictores de fracaso de la extubación.

Association between microcirculation in spontaneous breathing trial and extubation success

PURPOSE

This study assessed the association between changes in sublingual microcirculation after a spontaneous breathing trial (SBT) and successful extubation.

MATERIALS AND METHODS

Sublingual microcirculation was assessed using an incident dark-field video microscope before and after each SBT and before extubation. Microcirculatory parameters before the SBT, at the end of the SBT, and before extubation were compared between the successful and failed extubation groups.

RESULTS

Forty-seven patients were enrolled and analysed in this study (34 patients in the successful extubation group and 13 patients in the failed extubation group). At the end of the SBT, the weaning parameters did not differ between the two groups. However, the total small vessel density (21.2 [20.4-23.7] versus 24.9 [22.6-26.5] mm/mm²), perfused small vessel density (20.6 [18.5-21.8] versus 23.1 [20.9-25] mm/mm²), proportion of perfused small vessels (91 [87-96] versus 95 [93-98] %), and microvascular flow index (2.8 [2.7-2.9] versus 2.9 [2.9-3]) were significantly lower in the failed extubation group than in the successful extubation group. The weaning and microcirculatory parameters did not differ significantly between the two groups before the SBT.

CONCLUSIONS

More patients are required to investigate the difference between baseline microcirculation before a successful SBT and the change in microcirculation at the end of the SBT between the successful and failed extubation groups. Better sublingual microcirculatory parameters at the end of SBT and before extubation are associated with successful extubation.

Investigating the differences in nutritional status between successfully weaned and unsuccessfully weaned respirator patients

Long-term respirator users admitted to intensive care units need to be transferred to a respiratory care center (RCC) for weaning. It may cause malnutrition in critical care patients, which may manifest as a reduction in respiratory muscle mass, lower ventilatory capacity, and decreased respiratory tolerance. This study aimed to assess that if the patients' nutritional status were improved, it could help RCC patients to wean from respirators. All participants were recruited from the RCC of a medical foundation in the city and Taipei Tzu Chi Hospital. The indicators include serum albumin level, respirator detachment index, maximum inspiratory pressure (PImax), rapid shallow breathing index, and body composition measurements. We recorded the length of hospital stay, mortality, and RCW (respiratory care ward) referral rate for these participants and analyzed the differences in relevant research indicators between those who were and weren't weaned off. 43 of 62 patients were weaned from respirators, while 19 failed. The resuscitation rate was 54.8%. Patients with respirator weaning had a lower number of RCC admission days (23.1 ± 11.1 days) than respirator-dependent patients (35.6 ± 7.8 days, P < 0.05). The PImax of successfully weaned patients had a greater reduction (- 27.09 ± 9.7 cmH₂O) than unsuccessful ones (- 21.4 ± 10.2 cmH₂O, P < 0.05). The Acute Physiology and Chronic Health Evaluation II (APACHE II) scores of successfully weaned patients (15.8 ± 5.0) were lower than those who were not (20.4 ± 8.4, P < 0.05). There was no significant difference in serum albumin levels between the two groups. In the successfully weaned patients, the serum albumin concentration was increased from 2.2 ± 0.3 to 2.5 ± 0.4 mg/dL, P < 0.05. Improved nutritional status can help RCC patients to wean from respirators.

Identifying Novel Clusters of Patients With Prolonged Mechanical Ventilation Using Trajectories of Rapid Shallow Breathing Index

Objective

Patients with prolonged mechanical ventilation (PMV) are comprised of a heterogeneous population, creating great challenges for clinical management and study design. The study aimed to identify subclusters of PMV patients based on trajectories of rapid shallow breathing index (RSBI), and to develop a machine learning model to predict the cluster membership based on baseline variables.

Methods

This was a retrospective cohort study conducted in respiratory care center (RCC) at a tertiary academic medical center. The RCC referral criteria were patients with mechanical ventilation for at least 21 days with stable hemodynamic and oxygenation status. Patients admitted to the RCC from April 2009 to December 2020 were screened. Two-step clustering through linear regression modeling and k-means was employed to find clusters of the trajectories of RSBI. The number of clusters was chosen by statistical metrics and domain expertise. A gradient boosting machine (GBM) was trained, exploiting variables on RCC admission, to predict cluster membership.

Results

A total of 1371 subjects were included in the study. Four clusters were identified: cluster A showed persistently high RSBI; cluster B was characterized by a constant low RSBI over time; Cluster C was characterized by increasing RSBI; and cluster D showed a declining RSBI. Cluster A showed the highest mortality rate (72%), followed by cluster D (63%), C (62%) and B (61%; p = 0.005 for comparison between 4 clusters). GBM was able to predict cluster membership with an accuracy of &gt; 0.95 in ten-fold cross validation. Highly ranked variables for the prediction of clusters included thyroid-stimulating hormone (TSH), cortisol, platelet, free thyroxine (T4) and serum magnesium.

Conclusions

Patients with PMV are composed of a heterogeneous population that can be classified into four clusters by using trajectories of RSBI. These clusters can be easily predicted with baseline clinical variables.

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/.

Biosignal-Based Digital Biomarkers for Prediction of Ventilator Weaning Success

We evaluated new features from biosignals comprising diverse physiological response information to predict the outcome of weaning from mechanical ventilation (MV). We enrolled 89 patients who were candidates for weaning from MV in the intensive care unit and collected continuous biosignal data: electrocardiogram (ECG), respiratory impedance, photoplethysmogram (PPG), arterial blood pressure, and ventilator parameters during a spontaneous breathing trial (SBT). We compared the collected biosignal data's variability between patients who successfully discontinued MV (n = 67) and patients who did not (n = 22). To evaluate the usefulness of the identified factors for predicting weaning success, we developed a machine learning model and evaluated its performance by bootstrapping. The following markers were different between the weaning success and failure groups: the ratio of standard deviations between the short-term and long-term heart rate variability in a Poincaré plot, sample entropy of ECG and PPG, α values of ECG, and respiratory impedance in the detrended fluctuation analysis. The area under the receiver operating characteristic curve of the model was 0.81 (95% confidence interval: 0.70-0.92). This combination of the biosignal data-based markers obtained during SBTs provides a promising tool to assist clinicians in determining the optimal extubation time.

Association of weaning failure from mechanical ventilation with transthoracic echocardiography parameters: a systematic review and meta-analysis

BACKGROUND

Weaning from mechanical ventilation is a challenging step during recovery from critical illness. Weaning failure or early reintubation are associated with increased morbidity and mortality, exposing patients to life-threatening complications. Cardiac dysfunction represents the most common cause of weaning failure. We conducted a systematic review and meta-analysis to evaluate the association between transthoracic echocardiographic parameters and weaning failure.

METHODS

We performed a systematic search of MEDLINE and EMBASE screening for prospective studies providing echocardiographic data collected just before the beginning of spontaneous breathing trial and outcome of the weaning attempt. We primarily focused on parameters currently recommended for evaluation of left ventricular (LV) systolic or diastolic dysfunction.

RESULTS

We included 11 studies in our primary analysis, which included data on LV ejection fraction (LVEF, n=10 studies) and parameters recommended for the assessment of LV diastolic function (E/e' ratio n=10; E/A ratio n=9; E wave n=8; and e' wave n=7). Weaning failure was significantly associated to a higher E/e' ratio (standardised mean difference [SMD]=1.70, 95% confidence interval [CI; 0.78-2.62]; P<0.001), lower e' wave (SMD=-1.22, 95% CI [-2.33 to -0.11]; P=0.03), and higher E wave (SMD=0.97, 95% CI [0.29-1.65]; P=0.005). We found no association between weaning failure and LVEF (SMD=-0.86, 95% CI [-1.92-0.20]; P=0.11) and E/A ratio (SMD=0.00, 95% CI [-0.30-0.31]; P=0.98).

CONCLUSIONS

Weaning failure is associated with parameters indicating worse LV diastolic function (E/e', e' wave, E wave) and increased LV filling pressure (E/e' ratio). The association between weaning failure and LV systolic dysfunction as evaluated by LVEF is more unclear. More studies are needed to clarify this aspect and regarding the role of right ventricular function.

Electrical impedance tomography monitoring during spontaneous breathing trial: Physiological description and potential clinical utility

BACKGROUND

Readiness for mechanical ventilation (MecV) weaning and extubation is usually assessed clinically with the use of a spontaneous breathing trial (SBT), but its accuracy is limited, and the pathophysiology of weaning failure not completely elucidated. The purpose of the present study was to describe the physiological behavior of electrical impedance tomography parameters during SBT and to propose additional variables that could be helpful in defining weaning/extubation outcome.

METHODS

From December 2015 to January 2017, all subjects who remained under MecV with an orotracheal tube for more than 24 hours and who were submitted to SBT both in pressure-support ventilation (PSV) or T-tube were included in the study. Both clinical and impedance parameters were collected immediately before as well as during SBT.

RESULTS

Forty-two subjects were included in the final analysis. For subjects submitted to SBT in PSV, none of the impedance parameters added significant information regarding weaning outcomes. For subjects submitted to a T-tube SBT, a significant and progressive decrease in end-expiratory lung impedance (dEELI) was observed, which was more prominent in subjects who clinically failed the SBT. These subjects had a significant rapid shallow breathing index at the end of SBT.

CONCLUSIONS

dEELI was a potentially useful parameter in the evaluation of MecV weaning outcome when abrupt lung depressurization was induced during SBT in our study. The degree of dEELI decrease was probably related to the magnitude of lung derecruitment, which seems to play a key role in the MecV weaning outcome.

Dynamic data monitoring improves predictive analytics for failed extubation in the ICU

OBJECTIVE

Predictive analytics monitoring that informs clinicians of the risk for failed extubation would help minimize both the duration of mechanical ventilation and the risk of emergency re-intubation in ICU patients. We hypothesized that dynamic monitoring of cardiorespiratory data, vital signs, and lab test results would add information to standard clinical risk factors.

METHODS

We report model development in a retrospective observational cohort admitted to either the medical or surgical/trauma ICU that were intubated during their ICU stay and had available physiologic monitoring data (n  =  1202). The primary outcome was removal of endotracheal intubation (i.e. extubation) followed within 48 h by reintubation or death (i.e. failed extubation). We developed a standard risk marker model based on demographic and clinical data. We also developed a novel risk marker model using dynamic data elements-continuous cardiorespiratory monitoring, vital signs, and lab values.

RESULTS

Risk estimates from multivariate predictive models in the 24 h preceding extubation were significantly higher for patients that failed. Combined standard and novel risk markers demonstrated good predictive performance in leave-one-out validation: AUC of 0.64 (95% CI: 0.57-0.69) and 1.6 alerts per week to identify 32% of extubations that will fail. Novel risk factors added significantly to the standard model.

CONCLUSION

Predictive analytics monitoring models can detect changes in vital signs, continuous cardiorespiratory monitoring, and laboratory measurements in both the hours preceding and following extubation for those patients destined for extubation failure.