AARC Clinical Practice Guideline: Spontaneous Breathing Trials for Liberation From Adult Mechanical Ventilation.

Despite prior publications of clinical practice guidelines related to ventilator liberation, some questions remain unanswered. Many of these questions relate to the details of bedside implementation. We, therefore, formed a guidelines committee of individuals with experience and knowledge of ventilator liberation as well as a medical librarian. Using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology, we make the following recommendations: (1) We suggest that calculation of a rapid shallow breathing index is not needed to determine readiness for a spontaneous breathing trial (SBT) (conditional recommendation; moderate certainty); (2) We suggest that SBTs can be conducted with or without pressure support ventilation (conditional recommendation, moderate certainty); (3) We suggest a standardized approach to assessment and, if appropriate, completion of an SBT before noon each day (conditional recommendation, very low certainty); and (4) We suggest that FIO2 should not be increased during an SBT (conditional recommendation, very low certainty). These recommendations are intended to assist bedside clinicians to liberate adult critically ill patients more rapidly from mechanical ventilation.

Analyzing key elements of breathing patterns, deriving remaining variables, and identifying cutoff values in individuals with chronic respiratory disease and healthy subjects.

BACKGROUND: Pulmonary physiology encompasses intricate breathing patterns (BPs), characterized by breathing frequency (Bf), volumes, and flows. The complexities intensify in the presence of interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD), especially during exercise. This study seeks to identify pivotal factors driving changes among these variables and establish cutoff values, comparing their efficacy in differentiating BPs to traditional methods, specifically a breathing reserve (BR) of 30% and a Bf of 50 bpm. METHODS: Screening 267 subjects revealed 23 with ILD, 126 with COPD, 33 healthy individuals, and the exclusion of 85 subjects. Lung function tests and ramp-pattern cardiopulmonary exercise testing (CPET) were conducted, identifying crucial BP elements. Changes were compared between groups at peak exercise. The area under the receiver operating characteristic curve (AUC) analysis determined cutoff values. RESULTS: Inspiratory time (TI) remained constant at peak exercise for all subjects (two-group comparisons, all p=NS). Given known differences in expiratory time (TE) and tidal volume (VT) among ILD, COPD, and healthy states, constant TI could infer patterns for Bf, total breathing cycle time (TTOT=60/Bf), I:E ratio, inspiratory duty cycle (IDC, TI/TTOT), rapid shallow breathing index (Bf/VT), tidal inspiratory and expiratory flows (VT/TI and VT/TE), and minute ventilation (V̇E=Bf×VT) across conditions. These inferences aligned with measurements, with potential type II errors causing inconsistencies. RSBI of 23 bpm/L and VT/TI of 104 L/min may differentiate ILD from control, while V̇E of 54 L/min, BR of 30%, and VT/TE of 108 may differentiate COPD from control. BR of 21%, TE of 0.99 s, and IDC of .45 may differentiate ILD from COPD. The algorithm outperformed traditional methods (AUC 0.84-0.91 versus 0.59-0.90). CONCLUSION: The quasi-fixed TI, in conjunction with TE and VT, proves effective in inferring time-related variables of BPs. The findings have the potential to significantly enhance medical education in interpreting cardiopulmonary exercise testing. Moreover, the study introduces a novel algorithm for distinguishing BPs among individuals with ILD, COPD, and those who are healthy.

2022 Year in Review: Ventilator Liberation.

Mechanical ventilation is ubiquitous in critical care, and duration of ventilator liberation is variable and multifactorial. While ICU survival has increased over the last two decades, positive-pressure ventilation can cause harm to patients. Weaning and discontinuation of ventilatory support is the first step in ventilator liberation. Clinicians have a wealth of evidence-based literature at their disposal; however, more high-quality research is needed to describe outcomes. Additionally, this knowledge must be distilled into evidence-based practice and applied at the bedside. A proliferation of research on the subject of ventilator liberation has been published in the last 12 months. Whereas some authors have reconsidered the value of applying the rapid shallow breathing index in weaning protocols, others have begun to investigate new indices to predict liberation outcomes. New tools such as diaphragmatic ultrasonography have begun to appear in the literature as a tool for outcome prediction. A number of systematic reviews with both meta-analysis and network meta-analysis that synthesize the literature on ventilator liberation have also been published in the last year. This review describes changes in performance, monitoring of spontaneous breathing trials, and evaluations of successful ventilator liberation.

Static Respiratory System Compliance as a Predictor of Extubation Failure in Patients with Acute Respiratory Failure.

PURPOSE: Ventilator weaning protocols rely in part on objective indices to best predict extubation failure in the critically ill. We investigated static respiratory system compliance (RC) as a predictor of extubation failure, in comparison to extubation readiness using rapid shallow breathing index (RSBI). MATERIAL AND METHODS: This was a cross-sectional, multi-institutional study of mechanically ventilated patients admitted between 12/01/2017 and 12/01/2019. All patients older than 18 years with a documented spontaneous breathing trial and extubation trial were included. RC and RSBI were calculated prior to the extubation trial. The primary outcome was extubation failure-defined as need for reintubation within 72 h from time of extubation. RESULTS: Of the 2263 patients, 55.8% were males with a mean age of 68 years. The population consisted mostly of Caucasians (73%) and African Americans (20.4%). 274 (12.1%) patients required reintubation within 72 h. On multivariate logistic regression after adjusting for age, sex, body mass index (BMI), admission Sequential Organ Failure Assessment (SOFA) score, number of ventilator days, and the P/F ratio on the day of extubation, RC remained the strongest predictor for extubation failure at 24 h (aOR 1.45; 95% CI 1.00-2.10) and 72 h (aOR 1.58; 95% CI 1.15-2.17). There was no significant association between RSBI and extubation failure at 24 (aOR 1.00; 95% CI 0.99-1.01) or at 72 h (aOR 1.00; 95% CI 0.99-1.01). CONCLUSION: RC measured on the day of extubation is a promising physiological discriminant to potentially risk stratify patients with acute respiratory failure for extubation readiness. We recommend further validation studies in prospective cohorts.

Work of Breathing During Proportional Assist Ventilation as a Predictor of Extubation Failure.

BACKGROUND: Despite decades of research on predictors of extubation success, use of ventilatory support after extubation is common and 10-20% of patients require re-intubation. Proportional assist ventilation (PAV) mode automatically calculates estimated total work of breathing (total WOB). Here, we assessed the performance of total WOB to predict extubation failure in invasively ventilated subjects. METHODS: This prospective observational study was conducted in 6 adult ICUs at an academic medical center. We enrolled intubated subjects who successfully completed a spontaneous breathing trial, had a rapid shallow breathing index < 105 breaths/min/L, and were deemed ready for extubation by the primary team. Total WOB values were recorded at the end of a 30-min PAV trial. Extubation failure was defined as any respiratory support and/or re-intubation within 72 h of extubation. We compared total WOB scores between groups and performance of total WOB for predicting extubation failure with receiver operating characteristic curves. RESULTS: Of 61 subjects enrolled, 9.8% (n = 6) required re-intubation, and 50.8% (n = 31) required any respiratory support within 72 h of extubation. Median total WOB at 30 min on PAV was 0.9 J/L (interquartile range 0.7-1.3 J/L). Total WOB was significantly different between subjects who failed or were successfully extubated (median 1.1 J/L vs 0.7 J/L, P = .004). The area under the curve was 0.71 [95% CI 0.58-0.85] for predicting any requirement of respiratory support and 0.85 [95% CI 0.69-1.00] for predicting re-intubation alone within 72 h of extubation. Total WOB cutoff values maximizing sensitivity and specificity equally were 1.0 J/L for any respiratory support (positive predictive value [PPV] 70.0%, negative predictive value [NPV] 67.7%) and 1.3 J/L for re-intubation (PPV 26.3%, NPV 97.6%). CONCLUSIONS: The discriminative performance of a PAV-derived total WOB value to predict extubation failure was good, indicating total WOB may represent an adjunctive tool for assessing extubation readiness. However, these results should be interpreted as preliminary, with specific thresholds of PAV-derived total WOB requiring further investigation in a large multi-center study.

The ratio of respiratory rate to diaphragm thickening fraction for predicting extubation success.

BACKGROUND: Several parameters are used to predict successful extubation but their accuracy varies among studies. We hypothesized that combining conventional and diaphragmatic parameters would be more effective than using just one. Our primary objective was to evaluate the performance of the respiratory rate in relation to the diaphragm thickening fraction (RR/DTF) ratio to predict the success of extubation. METHODS: We enrolled 130 adult patients who required invasive mechanical ventilation, planned to be extubated, and used a spontaneous breathing trial (SBT) in the intensive care unit from July 2020 to April 2022. We measured the conventional parameters and the diaphragmatic parameters 2 h after SBT. The RR/DTF was calculated by dividing the respiratory rate (RR) by the diaphragm thickening fraction (DTF). The definition of weaning success is successful extubation within 48 h. RESULTS: Of 130 patients, 8 patients (6.2%) were reintubated within 48 h. The RR/DTF was significantly lower in the successful extubation group than in the extubation failure group (right hemidiaphragm; 0.47 (0.33-0.64) vs 1.1 (0.6-2.32), p < 0.001 and left hemidiaphragm; 0.45 (0.31-0.65) vs 0.78 (0.48-1.75), p < 0.001). The right RR/DTF using a cut-off point at ≤ 0.81 had a sensitivity of 87.7%, a specificity of 75%, and areas under the receiver operating characteristic curve (AUROC) of 0.762 for predicting successful extubation (p = 0.013). The sensitivity, specificity, and AUROC for predicting extubation success of right DTF at a cut-off point of ≥ 26.2% were 84.3%, 62.5%, and 0.775, respectively (p = 0.009). CONCLUSION: The RR/DTF ratio is a promising tool for predicting extubation outcome. Additionally, using RR/DTF was more reliable than conventional or diaphragmatic parameters alone in predicting extubation success.

Ultrasound Analysis of Respiration-Related Muscles in Rats.

The purpose of this study was to evaluate the effectiveness of ultrasound techniques in the analysis of respiratory-related muscles in rats. Respiratory parameters, including diaphragm end-expiratory thickness, mean rectus abdominis (RA) thickness, and RA area, were measured by ultrasound and compared with histological findings. Spearman's correlation and Logistic regression analysis were used to detect the differences in the correlation between ultrasound results and histological examinations, and Student's t test was used to compare the differences between ultrasound results and histological examination data. The results showed that there was no significant difference between the end-expiratory thickness of the diaphragm, the average thickness of RA, and the area of RA in the right RA and histological values under ultrasound detection (p > 0.05), but there was a significant positive correlation between ultrasound, and histological values (p < 0.05).); in addition, tidal volume was significantly positively correlated with total RA area, rapid shallow breathing index (RSBI) was significantly negatively correlated with total RA area, and mean diaphragm TF was significantly positively correlated with tidal volume. In conclusion, ultrasound imaging has a high degree of accuracy and reproducibility and can be used to assess the structure and function of the rat diaphragm and RA.

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 > 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.

Diaphragm ultrasound as a better predictor of successful extubation from mechanical ventilation than rapid shallow breathing index.

BACKGROUND: In 3%-19% of patients, reintubation is needed 48-72 hours following extubation, which increases intensive care unit (ICU) morbidity, mortality, and expenses. Extubation failure is frequently caused by diaphragm dysfunction. Ultrasonography can be used to determine the mobility and thickness of the diaphragm. This study looked at the role of diaphragm excursion (DE) and thickening fraction in predicting successful extubation from mechanical ventilation. METHODS: Thirty-one patients were extubated with the advice of an ICU consultant using the ICU weaning regimen and diaphragm ultrasonography was performed. Ultrasound DE and thickening fraction were measured three times: at the commencement of the t-piece experiment, at 10 minutes, and immediately before extubation. All patients' parameters were monitored for 48 hours after extubation. Rapid shallow breathing index (RSBI) was also measured at the same time. RESULTS: Successful extubation was significantly correlated with DE (P=0.01). Receiver curve analysis for DE to predict successful extubation revealed good properties (area under the curve [AUC], 0.83; P<0.001); sensitivity, 77.8%; specificity, 84.6%, positive predictive value (PPV), 87.5%; negative predictive value (NPV), 73.3% while cut-off value, 11.43 mm. Diaphragm thickening fraction (DTF) also revealed moderate curve properties (AUC, 0.69; P=0.06); sensitivity, 61.1%; specificity, 84.6%; PPV, 87.5%; NPV, 61.1% with cut-off value 22.33% although former one was slightly better. RSBI could not reach good receiver operating characteristic value at cut-off points 100 b/min/L (AUC, 0.58; P=0.47); sensitivity, 66.7%; specificity, 53.8%; PPV, 66.7%; NPV, 53.8%). CONCLUSIONS: To decrease the rate of reintubation, DE and DTF are better indicators of successful extubation. DE outperforms DTF.

Use of the Change in Weaning Parameters as a Predictor of Successful Re-Extubation.

OBJECTIVE: Weaning parameters are well studied in patients undergoing first time extubation. Fewer data exists to guide re-extubation of patients who failed their first extubation attempt. It is reasonable to postulate that improved weaning parameters between the first and second extubation attempt would lead to improved rates of re-extubation success. To investigate, we studied a cohort of patients who failed their first extubation attempt and underwent a second attempt at extubation. We hypothesized that improvement in weaning parameters between the first and the second extubation attempt is associated with successful reextubation. INTERVENTIONS: Rapid shallow breathing index (RSBI), maximum inspiratory pressure (MIP), vital capacity (VC), and the blood partial pressure of CO2 (PaCO2) were measured and recorded in the medical record prior to extubation along with demographic information. We examined the relationship between the change in extubation and re-extubation weaning parameters and re-extubation success. MEASUREMENTS AND MAIN RESULTS: A total of 1283 adult patients were included. All weaning parameters obtained prior to re-extubation differed between those who were successful and those who required a second reintubation. Those with reextubation success had slightly lower PaCO2 values (39.5 ± 7.4 mmHg vs. 41.6 ± 9.1 mmHg, p = 0.0045) and about 13% higher vital capacity volumes (1021 ± 410 mL vs. 907 ± 396 mL, p = 0.0093). Lower values for RSBI (53 ± 32 breaths/min/L vs. 69 ± 42 breaths/min/L, p < 0.001) and MIP (-41 ± 12 cmH2O vs. -38 ± 13 cm H2O), p = 0.0225) were seen in those with re-extubation success. Multivariable logistical regression demonstrates lack of independent associated between the change in parameters between the 2 attempts and re-extubation success. CONCLUSIONS: The relationship between the changes in extubation parameters through successive attempts is driven primarily by the value obtained immediately prior to re-extubation. These findings do not support waiting for an improvement in extubation parameters to extubate patients who failed a first attempt at extubation if extubation parameters are compatible with success.

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/.

Diaphragm Ultrasound: A Valuable Predictor of the Outcome of Extubation. An Observational Pilot Study in Covid-19 Related ARDS.

Introduction: Because both early and delayed weaning are associated with increased mortality, longer stay in the ICU and higher economic costs, performing extubation once the patient can cope with the respiratory load is completely recommended. Ultrasound Sonography (US) is an available bedside tool that allows a rapid assessment and visualization of the different structures involved in spontaneous breath. M-mode ultrasonography can be useful for the assessment of diaphragm kinetics, providing valuable information about diaphragm disfunction. Aim of the Study: The aim of this study is to find a correlation between the value of the acceleration of the diaphragm detected with the US M-mode and the outcome of the weaning. Materials and Methods: We have enrolled 19 patients admitted in our ICU. Each patient underwent the trial with the ultrasound M-mode to assess the acceleration of the diaphragm during the contraction. We have analyzed the results relating them to the outcome of the weaning. Results: While 11 of our patients have had a successful weaning, 8 have failed it, and we can see that the outcome is associated to the values of acceleration. Discussion: Our study has demonstrated that an assessment of the diaphragm function using US could represent a usable and effective technique as the acceleration is related to the force generated by the diaphragm contraction. Conclusions: In conclusion, the acceleration could be a useful parameter to consider when it comes to the prediction of the outcome of the weaning process.

[Factors Related to Successful Ventilator Weaning in Respiratory Care Center Patients: A Retrospective Chart Review Study].

BACKGROUND: The subacute respiratory care unit is an important relay station where respirator-dependent patients may access subsequent chronic respiratory care. Although there is relatively little information in the literature regarding respirator disconnections in subacute respiratory care units, assisting patients to disconnect successfully from respirators is a primary challenge for care teams. PURPOSE: The purpose of this study was to understand respirator disconnections and the factors affecting these events in subacute respiratory care units to improve the effectiveness of ventilator weaning and reduce the burden on families and medical care providers. METHODS: This was a retrospective chart review study. Patients admitted to the subacute respiratory care unit for respiratory training during the study period from January 2016 to December 2019 were recruited as subjects and the data were collected from the Chang Gung Medical Research Database`s health insurance secondary data using a self-made transcription form. RESULTS: The ventilator weaning success rate of the subjects in this study was 78.5%. A bivariate analysis revealed that consciousness status; disease severity; rapid shallow breathing index; days of hospitalization in a respiratory care center; days of ventilator use; blood urea nitrogen, white blood cell, hemoglobin, and blood albumin levels; and mean caloric intake were each significantly associated with successful ventilator withdrawal. The predictors of ventilator weaning in respiratory care center patients were identified as disease severity, rapid shallow breathing index, days of ventilator use, white blood cell level, and hemoglobin level. CONCLUSIONS / IMPLICATIONS FOR PRACTICE: Respirator-dependent patients should be evaluated and monitored as early as possible. Moreover, a ventilator weaning plan should be included as a regular testing and monitoring item. Also, a respirator removal program should be provided on a case-by-case basis. Individualized ventilator weaning programs may reduce the burden on families and medical care providers.

Validation of rapid shallow breathing index displayed by the ventilator compared to the standard technique in patients with readiness for weaning.

BACKGROUND: Rapid shallow breathing index (RSBI) is the most commonly used parameter for predicting weaning outcome. Measurement of RSBI by Wright spirometer (RSBIstandard) is the standard method in routine clinical practice. Data specific to the accuracy and reliability of the RSBI value displayed by the ventilator (RSBIvent) are scarce. Accordingly, this study aimed to evaluate the association between the average value of RSBIvent at different time points and RSBIstandard, and to assess the accuracy and reliability of these two RSBI measurement techniques. METHODS: This prospective cohort study included mechanically ventilated patients who were ready to wean. At the beginning of spontaneous breathing trial using the flow-by method, RSBI was measured by two different techniques at the same time, including: (1) Wright spirometer (breathing frequency/average tidal volume in 1 min) (RSBIstandard), and (2) the values displayed on the ventilator at 0, 15, 30, 45, and 60 s (RSBIvent). RESULTS: Forty-seven patients were enrolled. The RSBIvent value was significantly higher than the RSBIstandard value for every comparison. According to Spearman's correlation coefficient (r) and intraclass correlation coefficient (ICC), the average value of RSBI from 5 time points (0, 15, 30, 45, and 60 s) showed the best correlation with the standard technique (r = 0.76 [P < 0.001], and ICC = 0.79 [95% CI 0.61-0.88], respectively). Bland-Altman plot also showed the best agreement between RSBIstandard and the RSBIvent value averaged among 5 time points (mean difference - 17.1 breaths/min/L). CONCLUSIONS: We found that the ventilator significantly overestimates the RSBI value compared to the standard technique by Wright spirometer. The average RSBIvent value among 5 time points (0, 15, 30, 45, and 60 s) was found to best correlate with RSBIstandard.

Diaphragm thickening fraction predicts noninvasive ventilation outcome: a preliminary physiological study.

BACKGROUND: A correlation between unsuccessful noninvasive ventilation (NIV) and poor outcome has been suggested in de-novo Acute Respiratory Failure (ARF) patients. Consequently, it is of paramount importance to identify accurate predictors of NIV outcome. The aim of our preliminary study is to evaluate the Diaphragmatic Thickening Fraction (DTF) and the respiratory rate/DTF ratio as predictors of NIV outcome in de-novo ARF patients. METHODS: Over 36 months, we studied patients admitted to the emergency department with a diagnosis of de-novo ARF and requiring NIV treatment. DTF and respiratory rate/DTF ratio were measured by 2 trained operators at baseline, at 1, 4, 12, 24, 48, 72 and 96 h of NIV treatment and/or until NIV discontinuation or intubation. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the ability of DTF and respiratory rate/DTF ratio to distinguish between patients who were successfully weaned and those who failed. RESULTS: Eighteen patients were included. We found overall good repeatability of DTF assessment, with Intra-class Correlation Coefficient (ICC) of 0.82 (95% confidence interval 0.72-0.88). The cut-off values of DTF for prediction of NIV failure were < 36.3% and < 37.1% for the operator 1 and 2 (p < 0.0001), respectively. The cut-off value of respiratory rate/DTF ratio for prediction of NIV failure was > 0.6 for both operators (p < 0.0001). CONCLUSION: DTF and respiratory rate/DTF ratio may both represent valid, feasible and noninvasive tools to predict NIV outcome in patients with de-novo ARF. Trial registration ClinicalTrials.gov Identifier: NCT02976233, registered 26 November 2016.

Product of driving pressure and respiratory rate for predicting weaning outcomes.

OBJECTIVE: Clinicians cannot precisely determine the time for withdrawal of ventilation. We aimed to evaluate the performance of driving pressure (DP)×respiratory rate (RR) to predict the outcome of weaning. METHODS: Plateau pressure (Pplat) and total positive end-expiratory pressure (PEEPtot) were measured during mechanical ventilation with brief deep sedation and on volume-controlled mechanical ventilation with a tidal volume of 6 mL/kg and a PEEP of 0 cmH2O. Pplat and PEEPtot were measured by patients holding their breath for 2 s after inhalation and exhalation, respectively. DP was determined as Pplat minus PEEPtot. The rapid shallow breathing index was measured from the ventilator. The highest RR was recorded within 3 minutes during a spontaneous breathing trial. Patients who tolerated a spontaneous breathing trial for 1 hour were extubated. RESULTS: Among the 105 patients studied, 44 failed weaning. During ventilation withdrawal, DP×RR was 136.7±35.2 cmH2O breaths/minute in the success group and 230.2±52.2 cmH2O breaths/minute in the failure group. A DP×RR index >170.8 cmH2O breaths/minute had a sensitivity of 93.2% and specificity of 88.5% to predict failure of weaning. CONCLUSIONS: Measurement of DP×RR during withdrawal of ventilation may help predict the weaning outcome. A high DP×RR increases the likelihood of weaning failure.Statement: This manuscript was previously posted as a preprint on Research Square with the following link: https://www.researchsquare.com/article/rs-15065/v3 and DOI: 10.21203/rs.2.24506/v3.

Predictive efficacy of weaning index on mechanical ventilation evacuation.

BACKGROUND: The timely weaning of mechanical ventilation can shorten intensive care unit (ICU) stay times and reduce the complications related to mechanical ventilation. This study sought to investigate the predictive role of a weaning index (WI) on mechanical ventilation evacuation by measuring minute ventilation volume (MVV) across different ventilation modes. METHODS: Patients suffering from respiratory failure for a variety of reasons were included in the study if they received mechanical ventilation for more than 48 hours in the ICU. The patients were randomly allocated to either the assist/control (A/C) group or the pressure support ventilation (PSV) group according to the ventilator mode. The factors associated with weaning success and failure were analyzed. RESULTS: A total of 40 patients participated in this study. Of these, 25 weaning cases were successful and 15 were failures. There were 19 cases in the A/C group, yielding a success rate of 63%, and 21 cases in the PSV group, yielding a success rate of 62%. There were no significant differences between the two groups in terms of age, gender, ideal weight, Acute Physiology and Chronic Health Evaluation (APACHE) II score, ICU stay time and hospitalization time. There were significant differences in the mechanical ventilation duration between the two groups (P<0.05). When the WI was less than 50.44, the sensitivity and specificity of predicting weaning success were 72% and 98%. The area under the receiver operating characteristic (ROC) curve was 0.928±0.03. When the WI of the A/C group was less than 61.45, the sensitivity and specificity of predicting weaning success were 98% and 72%, respectively. The area under the ROC curve was 0.917±0.068. When the WI of the PSV group was less than 51.45, the sensitivity and specificity of predicting weaning success were 74.6% and 100%, respectively. The area under the ROC curve was 0.933±0.046. CONCLUSIONS: Compared with RSBI, WI shows a better value in predicting weaning, especially for mechanically ventilated patients in PSV mode, WI has greater value in predicting weaning.

A Reassessment of Weaning Parameters in Patients With Spontaneous Intracerebral Hemorrhage.

Background and purpose Patients with spontaneous intracerebral haemorrhage have significant morbidity and mortality. One aspect of their care is the need for mechanical ventilation. Extubating a patient safely and efficiently is important in advancing their care; however, traditional extubation criteria using the rapid shallow breathing index and negative inspiratory force do not predict success in these patients as well as they do in other intubated patients. This study aimed to evaluate these criteria in patients with spontaneous intracerebral haemorrhage to improve the extubation success rate. Methods We conducted a retrospective chart review of patients with spontaneous intracerebral haemorrhage (sICH) who underwent spontaneous breathing trials from 2018 to 2020. Twenty-nine patients met the inclusion criteria, and of these 29, 20 had a trial of extubation. Rapid shallow breathing index (RSBI), negative inspiratory force (NIF), and cuff leak were recorded to analyze breathing parameters at the time of extubation. Patients who required reintubation were noted. Results All trials of extubation required a cuff leak. Using RSBI, patients with values <105 or <85, as the only other extubation criteria, were associated with a 70.6% and 71.4% success rate, respectively. With RSBI <105 and NIF <-25 cm water, the success rate was 88.9%. Any patient with a cuff leak that had a NIF <-30 had a success rate of 100%, regardless of RSBI. Conclusion The RSBI was not a reliable isolated measure to predict 100% extubation success. Using a NIF <-30 predicts a 100% extubation success rate if a cuff leak is present. This demonstrates that the NIF may be a more useful metric in sICH patients, as it accounts for patient participation and innate ability to draw a breath spontaneously. Future studies are warranted to evaluate further and optimize the extubation criteria in these patients.

A clinical study on the ability of the integrative weaning index to predict weaning from mechanical ventilation.

BACKGROUND: Evaluate the accuracy of IWI predicting weaning in patients with mechanical ventilation greater than 72 hours. METHODS: All patients were divided into two groups, according to FiO2 in the intensive care unit (ICU) with mechanically ventilated for more than 72 hours. Recorded Integrative weaning index (IWI) related indicators in all patients. Evaluate the accuracy of IWI predicting weaning success. RESULTS: Within these 50 patients, 32 of them were weaning successfully, and 18 of the patients failed. Using IWI >45.70 mL/cmH2O breaths/minute/liter as a threshold of predicting successful weaning, the sensitivity is 0.91, and the specificity is 0.83. The AUC of IWI was 0.91. In the group with FiO2 =0.40, 17 patients were successfully liberated from MV, while 8 patients failed. The sensitivity is 0.8235, and specificity is 0.88 using IWI >50.40 mL/cmH2O breath/minute/liter as a threshold for predicting the outcome of weaning. The AUC of IWI was 0.846±0.117. In the FiO2 =0.35 group, 15 patients were successfully liberated from MV, while 10 patients failed. Using IWI >39.33 mL/cmH2O breaths/minute/liter, as a threshold to predict successful weaning, results in a sensitivity of 0.93 and a specificity of 0.90. The AUC of IWI was 0.953±0.395. CONCLUSIONS: Results showed IWI has a significantly higher AUC value compared with other traditional weaning indexes. Hence, it can be a significant predictor for weaning outcomes.