The effect of spontaneous breathing on systemic interleukin-6 during ventilator weaning

Predicting Successful Weaning through Sonographic Measurement of the Rapid Shallow Breathing Index

Background: Diaphragmatic dysfunction correlates with weaning failure, highlighting the need to independently assess the diaphragm's effects on weaning. We modified the rapid shallow breathing index (RSBI), a predictor of successful weaning, by incorporating temporal variables into existing ultrasound-derived diaphragm index to create a simpler index closer to tidal volume. Methods: We conducted a prospective observational study of patients who underwent a spontaneous breathing trial in the medical intensive care unit (ICU) at Severance Hospital between October 2022 and June 2023. Diaphragmatic displacement (DD) and diaphragm inspiratory time (Ti) were measured using lung ultrasonography. The modified RSBI was defined as follows: respiratory rate (RR) divided by DD was defined as D-RSBI, and RR divided by the sum of the products of DD and Ti on both sides was defined as DTi-RSBI. Results: Among the sonographic indices, DTi-RSBI had the highest area under the receiver operating characteristic (ROC) curve of 0.774 in ROC analysis, and a correlation was found between increased DTi-RSBI and unsuccessful extubation in a multivariable logistic regression analysis (adjusted odds ratio 0.02, 95% confidence interval 0.00-0.97). Conclusions: The DTi-RSBI is beneficial in predicting successful weaning in medical ICU patients.

Mean platelet volume as a predictive biomarker for in-hospital mortality in patients receiving invasive mechanical ventilation

Background

Although mean platelet volume (MPV) has been reported to be associated with poor prognosis of various critical illness, the relationship between MPV and in-hospital mortality among patients undergoing invasive mechanical ventilation (IMV) is unclear.

Methods

A retrospective observational study including patients receiving IMV was conducted from January, 2014 to January, 2019. The patients were divided into two groups by MPV cutoff value. The receiver operating characteristics curve was used to evaluate the predictive ability of MPV for in-hospital mortality. Univariate and multivariate Cox regression analysis were conducted to analyze the value of MPV for predicting in-hospital mortality. Kaplan–Meier cumulative incidence curve was employed to observe the incidence of in-hospital mortality.

Results

A total of 274 patients were enrolled in the study, and 42 patients (15.3%) died in hospital. MPV > 11.4 fl was a valuable predictor for in-hospital mortality (AUC0.848; 95%CI, 0.800–0.889) with sensitivity 66.7%, and specificity = 86.21%. MPV > 11.4 fl was an independent risk factor for in-hospital mortality (adjusted HR 2.640, 95%CI, 1.208–5.767, P = 0.015). Compared to the group of MPV ≤ 11.4 fl, patients with MPV > 11.4 fl had increased mortality (log-rank test = 40.35, HR = 8.723, P < 0.0001). The relationship between MPV and in-hospital mortality was stronger in female patients than in male patients.

Conclusion

MPV > 11.4 fl is a more useful marker for predicting in-hospital mortality among critically ill patients receiving IMV, especially in female patients. Attention to the MPV marker is simple and profitable with immediate applicability in daily clinical practice.

Mean platelet volume is useful for predicting weaning failure: a retrospective, observational study

Background

To evaluate the usefulness of mean platelet volume (MPV), a marker of inflammation and stress, for predicting weaning failure in patients undergoing invasive mechanical ventilation (IMV) compared to traditional inflammation markers.

Methods

The retrospective observational study including patients who received IMV and underwent spontaneous breathing trial (SBT) was conducted in ICU at Beijing Chao-Yang hospital in China from January, 2013 to December, 2019. According to the weaning outcome, MPV, leukocyte count and C-reaction protein(CRP) were compared between weaning failure and weaning success group. Receiver-operating characteristics (ROC) curves and multivariate logistical regression analysis were constructed to analyze the value of these inflammatory markers for predicting weaning failure.

Results

A total of 261 patients were enrolled in the study and 54 patients (20.7%) experienced weaning failure (45 SBT failure and 9 extubation failure after successful SBT). MPV was a better predictor for weaning failure (AUC 0.777;95%CI, 0.722–0.826) than leukocyte count (AUC 0.6;95%CI,0.538–0.66) and CRP (0.627;95%CI,0.565–0.685). The cutoff value of MPV for predicting weaning failure was 11.3 fl with sensitivity 55.56%, specificity 87.92%, and diagnostic accuracy 81.22%. According to multivariate logistic regression analyses, MPV > 11.3 fl was an independent risk factor for predicting weaning failure.

Conclusions

MPV could be a more valuable marker for predicting weaning failure. and the patients with MPV > 11.3 fl should be attentively evaluated before weaning since they are at high risk of weaning failure, and it would be auspicable for those patients to undergo a noninvasive ventilation or high-flow nasal cannula oxygen therapy after extubation or even an early tracheostomy.

Weaning Failure in Critically Ill Patients Is Related to the Persistence of Sepsis Inflammation

Introduction: Septic patients undergoing mechanical ventilation (MV) often experience difficulty in weaning. Th aim of this study was to determine whether inflammatory biomarkers of sepsis could be indicative of the failure or success of spontaneous breathing trial (SBT) in these patients. Methods: Sixty-five patients on MV (42 septic and 23 intubated for other reasons) fulfilling the criteria for SBT were included in the study. Blood samples were collected right before, at the end of (30 min) and 24 h after the SBT. Serum inflammatory mediators associated with sepsis (IL-18, IL-18BP, TNF) were determined and correlated with the outcome of SBT. Results: A successful SBT was achieved in 45 patients (69.2%). Septic patients had a higher percentage of SBT failure as compared to non-septic patients (85% vs. 15%, p = 0.026), with an odds ratio for failing 4.5 times (OR = 4.5 95%CI: 1.16–17.68, p 0.022). IL-18 levels and the relative mRNA expression in serum were significantly higher in septic as compared to non-septic patients (p < 0.05). Sepsis was independently associated with higher serum IL-18 and TNF levels in two time-point GEE models (53–723, p = 0.023 and 0.3–64, p = 0.048, respectively). IL-18BP displayed independent negative association with rapid shallow breathing index (RSBI) (95% CI: −17.6 to −4, p = 0.002). Conclusion: Sustained increased levels of IL-18 and IL-18BP, acknowledged markers of sepsis, were found to be indicative of SBT failure in patients recovering from sepsis. Our results show that, although subclinical, remaining septic inflammation that sustaines for a long time complicates the weaning procedure. Biomarkers for the estimation of the septic burden and the right time for weaning are needed.

Acute exacerbations of idiopathic pulmonary fibrosis: Does clinical stratification or steroid treatment matter?

Acute exacerbation (AE) of idiopathic pulmonary fibrosis (IPF) is defined as a sudden acceleration of the disease with the appearance of pulmonary infiltrates superimposed on the characteristic pattern of IPF that leads to a significant decline in lung function. It has high in-hospital mortality rates, despite medical treatment with systematic steroids. We sought to investigate whether there were in-hospital mortality differences according to clinical stratification (AE, suspected AE, or AE of known cause) and/or treatment with systemic steroids. We reviewed the clinical characteristics and outcomes of patients with IPF admitted to our hospital during the years 2003-2014 due to a worsening of their clinical status. We identified 50 IPF patients, 9 with AE (18%), 12 with suspected exacerbation (24%), and 29 with AE of known cause (58%), mostly respiratory infections. In-hospital mortality was similar in the three groups (33% vs. 17% vs. 34%, respectively). Likewise, we did not find differences between them with respect to the use of systemic steroids (length of treatment duration or total dose). Nevertheless, there was an independent association between in-hospital mortality and high average daily steroid dose. We did not observe significant differences in prognosis or use of systemic steroids according to current diagnostic stratification groups in patients hospitalized because of an exacerbation of IPF.

Changes in albuminuria during the spontaneous breathing trial: A prospective observational study

BACKGROUND

We hypothesized urine albumin concentration may detect the early increasing cardiac load during the spontaneous breathing trial (SBT). The purpose of our study is to determine whether the changes in urine albumin concentration before and after the SBT correlate with SBT outcome.

METHODS

This prospective observational study was conducted from January 2013 to September 2013. Patients receiving endotracheal tube intubation due to acute respiratory failure were included. Urine albumin concentration was measured upon admission to the intensive care unit, before and after the SBT.

RESULTS

A total of 211 patients with respiratory failure were screened. Finally, 69 patients were included for analysis. Among the 69 patients received the SBT, 61 patients passed the SBT while 8 patients didn't. Urine albumin concentration upon admission was 251.00 ± 108.21 mg/g in the SBT success group and 260.87 ± 77.95 mg/g in the SBT failure group (p = 0.97). The mean percent change in urine albumin concentration during the SBT was significantly higher in the SBT failure group (+58.44%) than in the SBT success group (+13.11%) (p = 0.02). Univariable and multivariable logistic regression model showed that the difference of urine albumin concentration before and after the SBT correlated significantly with SBT failure (adjusted OR:1.04, p = 0.01).

CONCLUSION

This open label pilot study demonstrates the significant association of the changes in urine albumin concentration with SBT outcome. Further study is warranted to investigate the predictive value of urine albumin concentration.

The Weaning Index combining EtCO2 and respiratory rate early identifies Spontaneous Breathing Trial failure

BACKGROUND

We aimed to evaluate the predictive value of the end-tidal CO2 (EtCO2) alone or combined with ventilation related parameters on Spontaneous Breathing Trial (SBT) outcome on mechanically ventilated patients.

METHODS

Prospective observational study in a medical Intensive Care Unit. Mechanically ventilated adult patients who met predefined criteria for weaning were included. Patients underwent a T-piece SBT for 30 minutes and the hemodynamic and respiratory clinical parameters including EtCO2 were recorded every five minutes.

RESULTS

The study included 280 patients, who were studied (age: 64±17 years, SAPS II: 44 [34-56]) during a first SBT and 76 patients during a second SBT. The Weaning Index, defined as the product of the respiratory rate and EtCO2, was a strong early predictive factor of SBT outcome; at 10 minutes, the area under the curve (AUC) was 86% ([80-90], P<0.0001) during the first SBT and 88% ([80-96], P<0.0001) during the second SBT. After 10 minutes of SBT, a Weaning Index >1100 identified patients that will not successfully complete the SBT at 30 minutes with a specificity of 98%.

CONCLUSIONS

In unselected mechanically ventilated patients, the Weaning Index is helpful to early identify patients who will fail the SBT during a first and a second trial.

Weaning from Mechanical Ventilation in ARDS: Aspects to Think about for Better Understanding, Evaluation, and Management

Acute respiratory distress syndrome (ARDS) is characterized by severe inflammatory response and hypoxemia. The use of mechanical ventilation (MV) for correction of gas exchange can cause worsening of this inflammatory response, called “ventilator-induced lung injury” (VILI). The process of withdrawing mechanical ventilation, referred to as weaning from MV, may cause worsening of lung injury by spontaneous ventilation. Currently, there are few specific studies in patients with ARDS. Herein, we reviewed the main aspects of spontaneous ventilation and also discussed potential methods to predict the failure of weaning in this patient category. We also reviewed new treatments (modes of mechanical ventilation, neuromuscular blocker use, and extracorporeal membrane oxygenation) that could be considered in weaning ARDS patients from MV.

Neutrophil/lymphocyte ratio is helpful for predicting weaning failure: a prospective, observational cohort study

Background

To assess the usefulness of the neutrophil/lymphocyte ratio (NLR), a marker of inflammation and/or stress, for predicting weaning failure in patients receiving invasive mechanical ventilation (IMV), compared to levels of leukocytes and C-reactive protein (CRP).

Methods

This observational prospective cohort study was conducted from July 2013 to December 2016 in an intensive care unit in China, enrolling 269 consecutive patients receiving IMV. Patients underwent a spontaneous breathing trial (SBT) if they were ready to wean, and underwent extubation if they passed the SBT. The evaluated markers were measured immediately prior to SBT, and compared between weaning-failure and weaning-success patients. Receiver-operating characteristic (ROC) curve and logistic regression analyses were used to evaluate the ability of these markers to predict weaning failure.

Results

In all, 94 (34.9%) patients failed the weaning process (66 failed SBT and 28 presented with post-extubation respiratory distress). NLR was a better predictor of failure (area under the ROC curve, 0.69; 95% CI, 0.62-0.76) than leukocyte levels (0.60, 0.53-0.67) and CRP values (0.58, 0.51-0.65). NLR >11, leukocyte counts >10.5×10⁹/L, and CRP >58 mg/L prior to weaning had the best combination of sensitivity (73%, 64%, and 63%, respectively), specificity (59%, 55%, and 63%), positive predictive value (49%, 43%, and 48%), negative predictive value (81%, 74%, and 76%), and diagnostic accuracy (64%, 58%, and 63%) for predicting weaning failure. However, only NLR >11 (odds ratio, 5.91; 95% CI, 3.08-11.33; P<0.001) was an independent predictor of weaning failure in the adjusted logistic regression model.

Conclusions

NLR may be a useful marker for predicting weaning failure, and weaning at NLR >11 might be considered with caution. Further study with a larger sample size and with weaning outcome as a variable of concern is warranted. Trial registration: ClinicalTrials.gov identifier: NCT02981589.

Evaluation of systemic inflammation in patients being weaned from mechanical ventilation

OBJECTIVES

The aim of this study was to evaluate systemic inflammatory factors and their relation to success or failure in a spontaneous ventilation test.

METHODS

This cross-sectional study included a sample of 54 adult patients. Demographic data and clinical parameters were collected, and blood samples were collected in the first minute of the spontaneous ventilation test to evaluate interleukin (IL)-1β, IL-6, IL-8, and IL-10, tumour necrosis factor alpha (TNFα) and C-reactive protein.

RESULTS

Patients who experienced extubation failure presented a lower rapid shallow breathing index than those who passed, and these patients also showed a significant increase in C-reactive protein 48 hours after extubation. We observed, moreover, that each unit increase in inflammatory factors led to a higher risk of spontaneous ventilation test failure, with a risk of 2.27 (1.001 - 4.60, p=0.049) for TNFα, 2.23 (1.06 - 6.54, p=0.037) for IL-6, 2.66 (1.06 - 6.70, p=0.037) for IL-8 and 2.08 (1.01 - 4.31, p=0.04) for IL-10, and the rapid shallow breathing index was correlated with IL-1 (r=-0.51, p=0.04).

CONCLUSIONS

C-reactive protein is increased in patients who fail the spontaneous ventilation test, and increased ILs are associated with a greater prevalence of failure in this process; the rapid shallow breathing index may not be effective in patients who present systemic inflammation.