Differences in clinical outcomes according to weaning classifications in medical intensive care units

Noninvasive ventilation for respiratory failure: When does it work and when it does not?

Noninvasive positive pressure ventilation (NIV) is a positive pressure ventilation method employed across various disease processes, utilizing noninvasive interfaces such as helmets and facemasks rather than invasive methods such as endotracheal intubation. The benefits of NIV are significant in both the acute care setting, such as improving work of breathing and avoiding the need for endotracheal intubation, as well as in the chronic care setting, improving quality of life and mortality. While new guidelines broaden the application of NIV across various disease areas and introduce emerging modalities, uncertainty persists regarding the appropriate timing and circumstances for NIV utilization. We present a detailed review of the literature with up-to-date studies assessing the indications and limitations of NIV in a variety of conditions associated with acute and chronic respiratory failure. The review also summarizes the current guidelines on the use of NIV in the acute care setting. Although primarily targeted towards the acute indications of NIV, we believe this review will aid in better understanding and managing noninvasive ventilation for clinicians across both the inpatient and outpatient settings.

Early weaning from invasive mechanical ventilation via high-flow nasal oxygen versus conventional weaning in patients with hypoxemic respiratory failure: a prospective randomized controlled study

OBJECTIVE

Although the efficacy of high-flow nasal oxygen therapy in delaying or avoiding intubation in patients with hypoxemic respiratory failure has been studied, its potential for facilitating early weaning from invasive mechanical ventilation remains unexplored.

METHODS

In this randomized controlled trial, 80 adults with acute hypoxemic respiratory failure requiring invasive mechanical ventilation for > 48 hours were enrolled and divided into two groups: conventional weaning and early weaning via high-flow nasal oxygen. In the conventional weaning group, the spontaneous breathing trial was performed after the PaO2/FiO2 ratio was ≥ 200, whereas in the high-flow nasal oxygen group, the spontaneous breathing trial was conducted earlier when the PaO2/FiO2 ratio was 150 - 200. Following each successful spontaneous breathing trial, patients were extubated and put on oxygen supplementation via a venturi mask or high-flow nasal oxygen on the basis of their group allocation. The primary objective was to compare extubation failure (reintubation within 48 hours). The secondary objectives were to compare total invasive mechanical ventilation, oxygen requirement and sedation requirement days, ventilator-associated pneumonia incidence, invasive mechanical ventilation-free days, intensive care unit length of stay, and intensive care unit all-cause mortality.

RESULTS

Extubation failure was not significantly different between the high-flow nasal oxygen group and the conventional weaning group [12.5% versus 25%, respectively; odds ratio (95%CI) 0.5 (0.19 - 1.33)] (p = 0.25). Early weaning from invasive mechanical ventilation via high-flow nasal oxygen was associated with significantly increased invasive mechanical ventilation-free days and total oxygen requirement days (p = 0.02 and p = 0.01, respectively). No significant between-group differences were observed in total invasive mechanical ventilation days, ventilator-associated pneumonia incidence, intensive care unit length of stay, sedation duration, or all-cause mortality.

CONCLUSION

Among patients with acute hypoxemic respiratory failure, early extubation with high-flow nasal oxygen is a feasible and superior alternative to the conventional method of weaning, as it increases the number of invasive mechanical ventilation-free days.

Development and validation of a model for predicting prolonged weaning from mechanical ventilation in patients with abdominal trauma

BACKGROUND

This study aimed to develop and validate a model to predict the risk of prolonged weaning from mechanical ventilation in patients with abdominal trauma.

METHODS

Patients with abdominal trauma were included and were divided into the training cohort and the validation cohort. The model was constructed using predictive factors identified by univariable and multivariable logistic regressions, and was validated by receiver operating characteristic curve, calibration curve, and decision curve analysis. Clinical outcomes were compared between model-stratified risk groups.

RESULTS

In total,190 patients were included, with 133 in the training cohort and 57 in the validation cohort. Six predictive factors, the Acute Physiology and Chronic Health Evaluation II score, Injury Severity Score, Glasgow coma scale, total bilirubin, skeletal muscle index, and abdominal fat index, were identified and were included in the model. The model predicting prolonged weaning owned a good discrimination, had an excellent calibration, and exhibited a favorable net benefit within a reasonable range of threshold probabilities. Significant differences were shown in prolonged weaning and clinical outcomes between the high-risk and low-risk groups (P < .05). Multivariable Cox regression analysis showed that patients in the high-risk group had greater risk of 28-day mortality (P < .05).

CONCLUSION

This study established a model to predict the risk of prolonged weaning from mechanical ventilation and clinical outcomes in patients with abdominal trauma. Skeletal muscle index was identified as one of independent risk factors of prolonged weaning. The findings offer valuable insights for respiratory management in patients with abdominal trauma.

Machine learning-based risk prediction model construction of difficult weaning in ICU patients with mechanical ventilation

In intensive care unit (ICU) patients undergoing mechanical ventilation (MV), the occurrence of difficult weaning contributes to increased ventilator-related complications, prolonged hospitalization duration, and a significant rise in healthcare costs. Therefore, early identification of influencing factors and prediction of patients at risk of difficult weaning can facilitate early intervention and preventive measures. This study aimed to strengthen airway management for ICU patients by constructing a risk prediction model with comprehensive and individualized offline programs based on machine learning techniques. This study involved the collection of data from 487 patients undergoing MV in the ICU, with a total of 36 variables recorded. The dataset was divided into a training set (70% of the data) and a test set (30% of the data). Five machine learning models, namely logistic regression, random forest, support vector machine, light gradient boosting machine, and extreme gradient boosting, were compared to predict the risk of difficult weaning in ICU patients with MV. Significant influencing factors were identified based on the results of these models, and a risk prediction model for ICU patients with MV was established. When evaluating the models using AUC (Area under the Curve of ROC) and Accuracy as performance metrics, the Random Forest algorithm exhibited the best performance among the five machine learning algorithms. The area under the operating characteristic curve for the subjects was 0.805, with an accuracy of 0.748, recall (0.888), specificity (0.767) and F1 score (0.825). This study successfully developed a risk prediction model for ICU patients with MV using a machine learning algorithm. The Random Forest algorithm demonstrated the highest prediction performance. These findings can assist clinicians in accurately assessing the risk of difficult weaning in patients and formulating effective individualized treatment plans. Ultimately, this can help reduce the risk of difficult weaning and improve the quality of life for patients.

Weaning difficulty after severe pneumonia in adult-onset mitochondrial myopathy with A3243G mutation in the mitochondrial tRNA gene: A case report

Background

Mitochondrial myopathy is a group of diseases caused by abnormal mitochondrial structure or function. The mitochondrial myopathy impacts muscles of the whole body and exhibits variable symptoms. Respiratory muscle deficits deteriorate pulmonary function in patients with severe pneumonia.

Case presentation

We report the case of a male patient with severe pneumonia-induced respiratory failure. He was abnormally dependent invasive ventilator-assisted ventilation after his condition had improved. Then we found abnormal ventilator waveform and a decline in muscle strength of him. Mitochondrial myopathy was ultimately confirmed by muscle pathological biopsy and body fluid genetic testing. Vitamin B complex, coenzyme Q10, Neprinol AFD, l-arginine, and MITO-TONIC were used to improve mitochondrial function and muscle metabolism. After treatment, discomfort associated with chest tightness, fatigue, cough, and sputum disappeared, and the patient was discharged.

Conclusion

This case presented an uncommon cause of difficult weaning and extubation-acute onset of mitochondrial myopathy. Muscle biopsy and genetic testing of body fluid are essential for diagnosing mitochondrial myopathy. The A3243G mutation in the MT-TL1 gene of mitochondrial DNA contributes to pathogenesis of this case.

An investigation on the respiratory mechanics of mechanically ventilated patients during spontaneous breathing trials with enhanced low-level pressure support ventilation

INTRODUCTION

Low-level pressure support ventilation (PSV) is most commonly adopted in spontaneous breathing trials (SBTs), and some have proposed setting the positive end-expiratory pressure (PEEP) to 0 cmH₂ O in order to shorten the observation time of SBTs. This study aims to investigate the effects of two PSV protocols on the patients' respiratory mechanics.

MATERIAL AND METHOD

A prospective randomized self-controlled crossover design was adopted in this study, which involved enrolling 30 difficult-to-wean patients who were admitted to the intensive care unit of the First Affiliated Hospital of Guangzhou Medical University between July 2019 and September 2021. Patients were subjected to the S group (pressure support: 8 cmH₂ O, PEEP: 5 cmH₂ O) and S1 group (PS: 8 cmH₂ O, PEEP: 0 cmH₂ O) for 30 min in a random order, and respiratory mechanics indices were dynamically monitored via a four-lumen multi-functional catheter with an integrated gastric tube. Among the 30 enrolled patients, 27 were successfully weaned.

RESULT

The S group showed higher airway pressure (Paw), intragastric pressure (Pga) and airway pressure-time product (PTP) than the S1 group. The S group also showed a shorter inspiratory trigger delay, (93.80 ± 47.85) versus (137.33 ± 85.66) ms (P = 0.004); and fewer abnormal triggers, (0.97 ± 2.65) versus (2.67 ± 4.48) (P = 0.042) compared with the S1 group. Stratification based on the causes of mechanical ventilation revealed that under the S1 protocol, patients with chronic obstructive pulmonary disease (COPD) had a longer inspiratory trigger delay compared to both post-thoracic surgery (PTS) patients and patients with acute respiratory distress syndrome. Despite providing greater respiratory support, S group led to significant reductions in inspiratory trigger delay and less abnormal triggers compared to S1 group, especially among patients with chronic obstructive pulmonary disease.

CONCLUSION

These findings suggest that the zero PEEP group was more likely to induce a higher number of patient-ventilator asynchronies in difficult-to-wean patients.

An artificial intelligence system to predict the optimal timing for mechanical ventilation weaning for intensive care unit patients: A two-stage prediction approach

BACKGROUND

For the intensivists, accurate assessment of the ideal timing for successful weaning from the mechanical ventilation (MV) in the intensive care unit (ICU) is very challenging.

PURPOSE

Using artificial intelligence (AI) approach to build two-stage predictive models, namely, the try-weaning stage and weaning MV stage to determine the optimal timing of weaning from MV for ICU intubated patients, and implement into practice for assisting clinical decision making.

METHODS

AI and machine learning (ML) technologies were used to establish the predictive models in the stages. Each stage comprised 11 prediction time points with 11 prediction models. Twenty-five features were used for the first-stage models while 20 features were used for the second-stage models. The optimal models for each time point were selected for further practical implementation in a digital dashboard style. Seven machine learning algorithms including Logistic Regression (LR), Random Forest (RF), Support Vector Machines (SVM), K Nearest Neighbor (KNN), lightGBM, XGBoost, and Multilayer Perception (MLP) were used. The electronic medical records of the intubated ICU patients of Chi Mei Medical Center (CMMC) from 2016 to 2019 were included for modeling. Models with the highest area under the receiver operating characteristic curve (AUC) were regarded as optimal models and used to develop the prediction system accordingly.

RESULTS

A total of 5,873 cases were included in machine learning modeling for Stage 1 with the AUCs of optimal models ranging from 0.843 to 0.953. Further, 4,172 cases were included for Stage 2 with the AUCs of optimal models ranging from 0.889 to 0.944. A prediction system (dashboard) with the optimal models of the two stages was developed and deployed in the ICU setting. Respiratory care members expressed high recognition of the AI dashboard assisting ventilator weaning decisions. Also, the impact analysis of with- and without-AI assistance revealed that our AI models could shorten the patients' intubation time by 21 hours, besides gaining the benefit of substantial consistency between these two decision-making strategies.

CONCLUSION

We noticed that the two-stage AI prediction models could effectively and precisely predict the optimal timing to wean intubated patients in the ICU from ventilator use. This could reduce patient discomfort, improve medical quality, and lower medical costs. This AI-assisted prediction system is beneficial for clinicians to cope with a high demand for ventilators during the COVID-19 pandemic.

Weak cough is associated with increased mortality in COPD patients with scheduled extubation: a two-year follow-up study

Background

Cough strength is associated with short-term outcome in patients with scheduled extubation who successfully complete a spontaneous breathing trial (SBT). However, the long-term outcome is unclear.

Methods

This was a prospective observational study performed in a respiratory ICU of a teaching hospital. COPD patients who successfully completed a SBT were candidates. We enrolled the case who assessed the cough strength by cough peak flow (CPF) or semiquantitative cough strength score (SCSS, ranging from 0 = weak to 5 = strong). Patients were followed up to two years by phone every 3 months.

Results

A total of 215 patients were enrolled in current study. Among them, CPF and SCSS were measured in 214 and 208 cases, respectively. Strong cough was associated with a 16% decrease in the risk of two-year mortality (adjusted hazard ratio [HR] 0.84, 95%CI: 0.78–0.91) per 10 L/min increment of CPF. When it was tested by SCSS, decrease in the risk of two-year mortality per unit increment was 27% (adjusted HR 0.73, 95%CI: 0.62–0.86). Similar results were confirmed in the discharged patients. In all patients, the two-year mortality was 75%, 53%, and 38% in patients with CPF < 60, 60–90, and > 90 L/min; and 85%, 70%, and 40% in patients with SCSS of 0–1, 2–3, and 4–5, respectively. Similar trend was found among the discharged patients whether it was assessed by CPF or SCSS.

Conclusions

In COPD patients, weak cough is associated with increased two-year mortality after a scheduled extubation. It provides objective information to caregivers to improve decision-making process during hospitalization and after discharge.

Comparison between pressure support ventilation and T-piece in spontaneous breathing trials

Background

Recent guidelines recommended conducting spontaneous breathing trial (SBT) with modest inspiratory pressure augmentation rather than T-piece or continuous positive airway pressure. However, it was based on few studies focused on the outcomes of extubation rather than the weaning process, despite the existence of various weaning situations in clinical practice. This study was designed to investigate the effects of SBT with pressure support ventilation (PSV) or T-piece on weaning outcomes.

Methods

All consecutive patients admitted to two medical intensive care units (ICUs) and those requiring mechanical ventilation (MV) for more than 24 h from November 1, 2017 to September 30, 2020 were prospectively registered. T-piece trial was used until March 2019, and then, pressure support of 8 cmH₂O and 0 positive end-expiratory pressure were used for SBT since July 2019, after a 3-month transition period for the revised SBT protocol. The primary outcome of this study was successful weaning defined according to the WIND (Weaning according to a New Definition) definition and were compared between the T-piece group and PSV group. The association between the SBT method and weaning outcome was evaluated with logistic regression analysis.

Results

In this study, 787 eligible patients were divided into the T-piece (n = 473) and PSV (n = 314) groups after excluding patients for a 3-month transition period. Successful weaning was not different between the two groups (85.0% vs. 86.3%; p = 0.607). However, the PSV group had a higher proportion of short weaning (70.1% vs. 59.0%; p = 0.002) and lower proportion of difficult weaning (13.1% vs. 24.1%; p < 0.001) than the T-piece group. The proportion of prolonged weaning was similar between the two groups (16.9% vs. 16.9%; p = 0.990). After excluding patients who underwent tracheostomy before the SBTs, similar results were found. Reintubation rates at 48 h, 72 h, and 7 days following the planned extubation were not different between the PSV and T-piece groups. Moreover, no significant differences in intensive care unit and hospital mortality and length of stay were observed.

Conclusions

In critically ill medical patients, SBT using PSV was not associated with a higher rate of successful weaning compared with SBT using T-piece. However, PSV could shorten the weaning process without increasing the risk of reintubation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-01942-w.

Weaning critically ill patients from mechanical ventilation: a protocol from a multicenter retrospective cohort study

BACKGROUND

Mechanical ventilation (MV) is an important lifesaving method in intensive care unit (ICU). Prolonged MV is associated with ventilator associated pneumonia (VAP) and other complications. However, premature weaning from MV may lead to higher risk of reintubation or mortality. Therefore, timely and safe weaning from MV is important. In addition, identification of the right patient and performing a suitable weaning process is necessary. Although several guidelines about weaning have been reported, compliance with these guidelines is unknown. Therefore, the aim of this study is to explore the variation of weaning in China, associations between initial MV reason and clinical outcomes, and factors associated with weaning strategies using a multicenter cohort.

METHODS

This multicenter retrospective cohort study will be conducted at 17 adult ICUs in China, that included patients who were admitted in this 17 ICUs between October 2020 and February 2021. Patients under 18 years of age and patients without the possibility for weaning will be excluded. The questionnaire information will be registered by a specific clinician in each center who has been evaluated and qualified to carry out the study.

DISCUSSION

In a previous observational study of weaning in 17 ICUs in China, weaning practices varies nationally. Therefore, a multicenter retrospective cohort study is necessary to be conducted to explore the present weaning methods used in China.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR) (No. ChiCTR2100044634).

Factors associated with prolonged weaning from mechanical ventilation in medical patients

BACKGROUND

Patients who need prolonged mechanical ventilation (MV) have high resource utilization and relatively poor outcomes. The pathophysiologic mechanisms leading to weaning failure in this group may be complex and multifactorial. The aim of this study was to investigate the factors associated with prolonged weaning based on the Weaning Outcome according to a New Definition (WIND) classification.

METHODS

This is a prospective observational study with consecutive adult patients receiving MV for at least two calendar days in medical intensive care units from 1 November 2017 to 30 September 2020. Eligible patients were divided in a non-prolonged weaning group, including short and difficult weaning, and in a prolonged weaning group according to the WIND classification. The risk factors at the time of first separation attempt associated with prolonged weaning were analyzed using a multivariable logistic regression model.

RESULTS

Of the total 915 eligible patients, 172 (18.8%) patients were classified as prolonged weaning. A higher proportion of the prolonged weaning group had previous histories of endotracheal intubation, chronic lung disease, and hematologic malignancies. When compared with the non-prolonged weaning group, the median duration of MV before the first spontaneous breathing trial (SBT) was longer and the proportion of tracheostomized patients was higher in prolonged weaning group. In addition, the prolonged weaning group used higher peak inspiratory pressures and yielded lower PaO₂/FiO₂ ratios at the day of the first SBT compared with the non-prolonged weaning group. In multivariate analyses, the duration of MV before first SBT (adjusted odds ratio [OR] = 1.14, 95% confidence interval [CI] = 1.06-1.22, p < 0.001), tracheostomy state (adjusted OR = 1.95, 95% CI = 1.04-3.63, p = 0.036), PaO₂/FiO₂ ratio (adjusted OR = 1.00, 95% CI = 0.99-1.00, p = 0.023), and need for renal replacement therapy (adjusted OR = 2.68, 95% CI = 1.16-6.19, p = 0.021) were independently associated with prolonged weaning. After the exclusion of patients who underwent tracheostomy before the SBTs, similar results were obtained.

CONCLUSION

Longer duration of MV before the first SBT, tracheostomy status, poor oxygenation, and need for renal replacement therapy at the time of first SBT can predict prolonged weaning.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT05134467.

A new protocol to compare successful versus failed patients using the electromyographic diaphragm signal in extubation process

In clinical practice, when a patient is undergoing mechanical ventilation, it is important to identify the optimal moment for extubation, minimizing the risk of failure. However, this prediction remains a challenge in the clinical process. In this work, we propose a new protocol to study the extubation process, including the electromyographic diaphragm signal (diaEMG) recorded through 5-channels with surface electrodes around the diaphragm muscle. First channel corresponds to the electrode on the right. A total of 40 patients in process of withdrawal of mechanical ventilation, undergoing spontaneous breathing tests (SBT), were studied. According to the outcome of the SBT, the patients were classified into two groups: successful (SG: 19 patients) and failure (FG: 21 patients) groups. Parameters extracted from the envelope of each channel of diaEMG in time and frequency domain were studied. After analyzing all channels, the second presented maximum differences when comparing the two groups of patients, with parameters related to root mean square (p = 0.005), moving average (p = 0.001), and upward slope (p = 0.017). The third channel also presented maximum differences in parameters as the time between maximum peak (p = 0.004), and the skewness (p = 0.027). These results suggest that diaphragm EMG signal could contribute to increase the knowledge of the behaviour of respiratory system in these patients and improve the extubation process.Clinical Relevance-This establishes the characterization of success and failure patients in the extubation process.

Impact of peripheral muscle strength on prognosis after extubation and functional outcomes in critically ill patients: a feasibility study

The influence of peripheral muscle strength on prognosis after extubation and subsequent functional outcomes is not evident. The objectives of this study were to determine (1) whether peripheral muscle strength can be used as a predictor for patients' prognoses after extubation, and (2) whether the peripheral muscle strength before extubation is correlated with patients' subsequent ambulation ability and in-hospital mortality. This study was a prospective observational cohort study. A hand-held dynamometer was used for evaluated the muscle strength of the biceps and quadriceps right before extubation. Besides, after the patients had been transferred from the ICU to the general ward, a 2-minute walk test was performed. A total of 52 patients were enrolled in this study, and the rate of extubation failure was 15%. The muscle strength of the quadriceps was significantly correlated with the prognosis after extubation, 48% of the patients were able to ambulate after being transferred to the general ward. The overall mortality rate was 11%, and there was a significant correlation between the biceps muscle strength and in-hospital mortality. Peripheral muscle strength may serve as an important predictor of a patients' prognoses after extubation. Poor peripheral muscle strength is indicative of not only a higher risk of re-intubation but also higher in-hospital mortality and poorer functional outcomes.Trial registration: ISRCTN16370134. Registered 30 May 2019, prospectively registered. https://www.isrctn.com/ISRCTN16370134 .

Preventive use of non-invasive ventilation is associated with reduced risk of extubation failure in patients on mechanical ventilation for more than 7 days: a propensity-matched cohort study

BACKGROUND

Extubation failure (EF) is high in patients on mechanical ventilation for more than 7 days. However, strategies to prevent EF in this population are lacking.

AIMS

To evaluate the efficacy of preventive use of noninvasive ventilation in patients on mechanical ventilation for more than 7 days.

METHODS

We performed a retrospective study in an intensive care unit of a teaching hospital. We enrolled patients who received mechanical ventilation for more than 7 days and successfully completed a weaning trial. After extubation, patients who immediately received non-invasive ventilation (NIV) were classified as the NIV group, and those who received conventional oxygenation therapy only were classified as the usual care group.

RESULTS

We enrolled 95 patients in the NIV group and 61 patients in the usual care group. NIV is associated with reduced risk of EF compared to usual care both 72 h following extubation (11.6% vs 32.8%, P < 0.01, for the overall cohort; 8.6% vs 42.9%, P < 0.01, for the propensity-matched cohort) and 7 days following extubation (25.3% vs 45.9%, P < 0.01, for the overall cohort; 28.6% vs 51.4%, P = 0.09, for the propensity-matched cohort). Within 7 days of extubation, the NIV group had a lower proportion of EF than the controls (log rank test: P < 0.01 and P = 0.02 for the overall and propensity-matched cohorts, respectively).

CONCLUSIONS

In patients on mechanical ventilation for more than 7 days, preventive use of NIV is associated with a reduction in EF.

Machine learning for the prediction of successful extubation among patients with mechanical ventilation in the intensive care unit: A retrospective observational study

BACKGROUND

Ventilator weaning protocols are commonly implemented for patients receiving mechanical ventilation. However, the rate of extubation failure remains high despite the protocols. This study investigated the usefulness and accuracy of ventilator weaning through machine learning to predict successful extubation.

METHODS

We retrospectively evaluated the data of patients who underwent intubation for respiratory failure and received mechanical ventilation in the intensive care unit (ICU). Data on 57 factors including patient demographics, vital signs, laboratory data, and data from ventilator were extracted. Extubation failure was defined as re-intubation within 72 hours of extubation. For supervised learning, the data were labeled requirement of intubation or not. We used three learning algorithms (Random Forest, XGBoost, and LightGBM) to predict successful extubation. We also analyzed important features and evaluated the area under curve (AUC) and prediction metrics.

RESULTS

Overall, 13 of the 117 included patients required re-intubation. LightGBM had the highest AUC (0.950), followed by XGBoost (0.946) and Random Forest (0.930). The accuracy, precision, and recall performance were 0.897, 0.910, and 0.909, for Random Forest; 0.910, 0.912, and 0.931 for XGBoost; and 0.927, 0.915, and 0.960 for LightGBM, respectively. The most important feature was the duration of mechanical ventilation followed by the fraction of inspired oxygen, positive end-expiratory pressure, maximum and mean airway pressures, and Glasgow Coma Scale.

CONCLUSIONS

Machine learning could predict successful extubation among patients on mechanical ventilation in the ICU. LightGBM has the highest overall performance. The duration of mechanical ventilation was the most important feature in all models.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Effect of post-extubation high-flow nasal cannula on reintubation in elderly patients: a retrospective propensity score-matched cohort study

Background:

Studies of mechanically ventilated patients with a low risk of reintubation have suggested that the use of high-flow nasal cannula (HFNC) oxygen therapy reduces the risk of reintubation compared with conventional oxygen therapy (COT). However, the effect of HFNC following extubation in elderly patients with a high risk of reintubation remains unclear.

Methods:

All consecutive medical intensive care unit (ICU) patients aged >65 years who were mechanically ventilated for >24 h were prospectively registered between July 2017 and June 2018. Control was obtained from a historical database of patients attending the same ICU from January 2012 to December 2013. A total of 152 patients who underwent HFNC after planned extubation according to institutional protocols (HFNC group) were compared with a propensity-matched historical control group who underwent COT (n = 175, COT group). The primary outcome was the proportion of reintubated patients within 48 h after planned extubation.

Results:

One hundred patients from the HFNC group and 129 patients from the COT group were matched by a propensity score that reflected the probability of receiving HFNC, and all variables were well matched. Post-extubation respiratory failure (41.0% versus 33.3%, p = 0.291) and reintubation rate within 48 h (16.0% versus 11.6%, p = 0.436) did not differ between the HFNC and COT groups. However, decreased levels of consciousness as a sign of post-extubation respiratory failure (27.0% versus 11.7%, p = 0.007) were significantly increased in the HFNC group compared with the COT group.

Conclusion:

Among elderly patients who underwent planned extubation, HFNC was not associated with a decrease in the risk of reintubation. Further prospective study evaluating the clinical benefits of post-extubation HFNC in elderly patients is needed.

The reviews of this paper are available via the supplemental material section.

Diaphragm and Lung Ultrasound Indices in Prediction of Outcome of Weaning from Mechanical Ventilation in Pediatric Intensive Care Unit

OBJECTIVE

To predict the added value of diaphragmatic and lung ultrasound indices (US) in anticipation of the outcome of mechanical ventilation of pediatric patients in the intensive care unit.

METHODS

This prospective study was conducted in Zagazig University, Pediatric Hospitals, PICU; Egypt. One hundred six mechanically ventilated children aged between 1 mo to 170 mo were included in the study. All patients were candidates for weaning and have been given a chance for spontaneous breathing trial (SBT), during which diaphragmatic and lung US was performed for them. The diaphragm thickening fraction (DTF), the diaphragmatic excursion and the lung US score (LUS), that included 4 US aeration forms, were assessed.

RESULTS

There were statistically significant differences between patients with failed weaning and those with successful weaning regarding DTF, diaphragmatic excursion and LUS (p < 0.001). The best cut-off value of DTF, diaphragmatic excursion, and LUS for predicting weaning failure was ≥23.175%, ≥ 6.2 mm, and ≥ 12 with an AUC (area under curve) of 0.932, 0.876, and 0.934, respectively.

CONCLUSIONS

Diaphragmatic and lung US add a quick, accurate and non-invasive indices to the weaning readiness parameters compared to the other standard parameters alone. So, it is recommended to be added to the predictive parameters of weaning outcome.

Prolonged Weaning from Mechanical Ventilation

BACKGROUND

To accommodate the increasing number of patients requiring prolonged weaning from mechanical ventilation, specialized weaning centers have been established for patients in whom weaning on the intensive care unit (ICU) was unsuccessful.

METHODS

This study aimed to determine both the outcome of treatment and the factors associated with prolonged weaning in patients who were transferred from the ICU to specialized weaning centers in Germany during the period 2011 to 2015, based on a nationwide registry covering all specialized weaning centers currently going through the process of accreditation by the German Respiratory Society.

RESULTS

Of 11 424 patients, 7346 (64.3%) were successfully weaned, of whom 2236 were switched to long-term non-invasive ventilation; 1658 (14.5%) died in the weaning unit; and 2420 (21.2%) could not be weaned. The duration of weaning decreased significantly from 22 to 18 days between 2011 and 2015 (p <0.0001). Multivariate analysis revealed that the factor most strongly associated with in-hospital mortality was advanced age (odds ratio [OR] 11.07, 95% confidence interval [6.51; 18.82], p <0.0001). The need to continue with invasive ventilation was most strongly associated with the duration mechanical ventilation prior to transfer from the ICU (OR 4.73 [3.25; 6.89]), followed by a low body mass index (OR 0.38 [0.26; 0.58]), pre-existing neuromuscular disorders (OR 2.98 [1.88; 4.73]), and advanced age (OR 2.96 [1.87; 4.69]) (each p <0.0001).

CONCLUSION

Weaning duration has decreased over time, but prolonged weaning is still unsuccessful in one third of patients.Overall, the results warrant the establishment of specialized weaning centers. Variables associated with death and weaningfailure can be integrated into ICU decision-making processes.

Comparison of International Consensus Conference guidelines and WIND classification for weaning from mechanical ventilation in Brazilian critically ill patients: A retrospective cohort study

The knowledge of weaning ventilation period is fundamental to understand the causes and consequences of prolonged weaning. In 2007, an International Consensus Conference (ICC) defined a classification of weaning used worldwide. However, a new definition and classification of weaning (WIND) were suggested in 2017. The objective of this study was to compare the incidence and clinical relevance of weaning according to ICC and WIND classification in an intensive care unit (ICU) and establish which of the classifications fit better for severely ill patients. This study was a retrospective cohort study in an ICU in a tertiary University Hospital. Patient data, such as population characteristics, mechanical ventilation (MV) duration, weaning classification, mortality, SAPS 3, and death probability, were obtained from a medical records database of all patients, who were admitted to ICU between January 2016 and July 2017. Three hundred twenty-seven mechanically ventilated patients were analyzed. Using the ICC classification, 82% of the patients could not be classified, while 10%, 5%, and 3% were allocated in simple, difficult, and prolonged weaning, respectively. When WIND was used, 11%, 6%, 26%, and 57% of the patients were classified into short, difficult, prolonged, and no weaning groups, respectively. Patients without classification were sicker than those that could be classified by ICC. Using WIND, an increase in death probability, MV days, and tracheostomy rate was observed according to weaning difficult. Our results were able to find the clinical relevance of WIND classification, mainly in prolonged, no weaning, and severely ill patients. All mechanically ill patients were classified, even those sicker with tracheostomy and those that could not finish weaning, thereby enabling comparisons among different ICUs. Finally, it seems that the new classification fits better in the ICU routine, especially for more severe and prolonged weaning patients.

Sarcopenia is an effective predictor of difficult-to-wean and mortality among critically ill surgical patients

BACKGROUND

Critically-ill surgical patients are at higher risk for sarcopenia, which is associated with worse survival. Sarcopenia may impair the respiratory musculature, which can subsequently influence the outcome of ventilator weaning. Although there are a variety of weaning parameters predictive of weaning outcomes, none have tried to incorporate "muscle strength" or "sarcopenia". The aim of the current study was to explore the association between sarcopenia and difficult-to-wean (DtW) in critically-ill surgical patients. The influence of sarcopenia on ICU mortality was also analyzed.

METHODS

Ninety-six patients undergoing mechanical ventilation in the surgical intensive care unit (ICU) were enrolled. Demographic data and weaning parameters were recorded from the prospectively collected database, and the total psoas muscle area (TPA) was determined at the level of the 3rd lumbar vertebra by computed tomography. Sarcopenia was defined by previously established cut-off points and its influence on clinical outcomes was examined. Receiver operating characteristic (ROC) curve analysis was conducted to investigate the predictive capability of TPA and weaning parameters for predicting weaning outcomes.

RESULTS

The median age of the studied patients was 73 years. Thirty patients (31.3%) were sarcopenic and 30 (31.3%) were defined as DtW. Eighteen patients (18.8%) had ICU mortality. Multivariate logistic regression analyses revealed that sarcopenia was an independent risk factor for DtW and ICU mortality. The area under the ROC curve (AUC) of TPA for predicting successful weaning was 0.727 and 0.720 in female and male patients, respectively. After combining TPA and conventional weaning parameters, the AUC for DtW increased from 0.836 to 0.911 and from 0.835 to 0.922 in female and male patients, respectively.

CONCLUSION

Sarcopenia is an independent risk factor for DtW and ICU mortality. TPA has predictive value when assessing weaning outcomes and can be used as an effective adjunct predictor along with conventional weaning parameters.

Outcomes of mechanical ventilation according to WIND classification in pediatric patients

Background

The outcomes of weaning processes are not well known in pediatric patients, and the International Conference Classification on weaning from mechanical ventilation showed limited application. We evaluate the relationship between the new Weaning according to a New Definition (WIND) classification and outcome in pediatric patients.

Methods

We conducted a retrospective cohort study in a tertiary pediatric intensive care unit (ICU). We included patients under 18 years of age who received invasive mechanical ventilation for more than 24 h and excluded cases with other than the first ICU admissions, tracheostomy with home ventilation before admission, intubation or weaning processes conducted in other ICU, and weaning with extracorporeal membrane oxygenation. Weaning processes were classified into four groups according to weaning duration after the first separation attempt (SA): no-SA, short weaning (< 24 h), difficult weaning (24 h–7 days), and prolonged weaning (> 7 days). Mortality rates were compared across groups using the Kruskal–Wallis test, and risk factors for the no-SA group were analyzed by multivariate logistic regression tests with age, sex, severity score at admission, admission type, and underlying disease as variables.

Results

Among 313 patients, 224 were enrolled and had a median age of 2.1 (interquartile range 0.5–6.6) years. Spontaneous breathing tests were done in 70.1% of enrolled patients. The median duration of intubation to the first SA was 4 (range 0–36) days, and 92.8% patients underwent the first SA within 14 days. The mortality rate was 0% in the short (0/99) and difficult (0/53) weaning groups and 17.9% (5/28) in the prolonged weaning group (p < 0.001). The mortality rate of the no-SA group was 93.2% (41/44). Admission severity (hazard ratio 1.036, confidence interval 1.022–1.050) and underlying oncologic disease (hazard ratio 7.341, confidence interval 3.008–17.916) were independent risk factors for lack of SA.

Conclusions

In conclusion, WIND classification is associated with ICU mortality in pediatric patients. Further studies of this association are required to improve protocols associated with the weaning process and clinical outcomes.

Trial registration Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0547-2) contains supplementary material, which is available to authorized users.

A systematic review of interventions to facilitate extubation in patients difficult-to-wean due to delirium, agitation, or anxiety and a meta-analysis of the effect of dexmedetomidine

BACKGROUND

Delirium, agitation, and anxiety may hinder weaning from mechanical ventilation and lead to increased morbidity and healthcare costs. The most appropriate clinical approach to weaning in these contexts remains unclear and challenging to clinicians. The objective of this systematic review was to identify effective and safe interventions to wean patients that are difficult-to-wean from mechanical ventilation due to delirium, agitation, or anxiety.

METHODS

A systematic review was performed using MEDLINE, EMBASE, and PubMed. Studies evaluating mechanically ventilated patients deemed difficult-to-wean due to delirium, agitation, or anxiety, and comparing the effects of an intervention with a comparator arm were sought. Time-to-extubation was the primary outcome while the secondary outcome was intensive care unit (ICU) length of stay.

RESULTS

From 10,860 studies identified, eight met the inclusion criteria: six studies assessed dexmedetomidine while the remaining two assessed loxapine and biofeedback. Pooled analysis of studies assessing dexmedetomidine showed reduced time-to-extubation (six studies, n = 303) by 10.9 hr compared with controls (95% confidence interval [CI], -15.7 to -6.1; I² = 68%) and ICU length of stay (four studies, n = 191) by 2.6 days (95% CI, 1.9 to 3.3; I² = 0%). Nevertheless, the evidence was deemed to be of low quality given the small sample sizes and high heterogeneity. Studies assessing other interventions did not identify improvements compared with controls. Safety assessment was globally poorly reported.

CONCLUSIONS

This systematic review and meta-analysis provides low quality evidence to suggest the use of dexmedetomidine in patients deemed difficult-to-wean due to agitation, delirium, or anxiety. Insufficient evidence was found regarding other interventions to provide any recommendation.

TRIAL REGISTRATION

PROSPERO (CRD42016042528); registered 15 July, 2016.

Non-invasive ventilation as a strategy for weaning from invasive mechanical ventilation: a systematic review and Bayesian meta-analysis

PURPOSE

A systematic review and meta-analysis was conducted to answer the question 'In adults with respiratory failure requiring invasive ventilation for more than 24 h, does a weaning strategy with early extubation to non-invasive ventilation (NIV) compared to invasive ventilation weaning reduce all-cause hospital mortality?'

METHODS

We included randomised and quasi-randomised controlled trials that evaluated the use of non-invasive ventilation, compared to invasive ventilation, as a weaning strategy in adults mechanically ventilated for at least 24 h. The EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials (CENTRAL) bibliographic databases were searched from inception to February 2018. Bayesian hierarchical models were used to perform the meta-analysis. The primary outcome was mortality at hospital discharge. Secondary outcomes included mortality (30, 60, 90 and 180 days), quality of life, duration of invasive ventilation, weaning failure, length of stay [intensive care unit (ICU) and hospital] and adverse events.

RESULTS

Twenty-five relevant studies involving 1609 patients were included in the quantitative analysis. Studies had moderate to high risk of bias due to risk of performance and detection bias. Mortality at hospital discharge was lower in the NIV weaning group compared to the invasive weaning group [pooled odds ratio (OR) 0.58, 95% highest density interval (HDI) 0.29-0.89]. Subgroup analyses showed lower pooled mortality at hospital discharge rates in NIV weaning than those in the control group in chronic obstructive pulmonary disease (COPD) patients (pooled OR 0.43, 95% HDI 0.13-0.81) and the effect is less certain in the mixed ICU population (pooled OR 0.88, 95% HDI 0.25-1.48). NIV weaning reduced the duration of invasive ventilation in patients [standardised mean difference (SMD) - 1.34, 95% HDI - 1.92 to - 0.77] and ICU length of stay (SMD - 0.70, 95% HDI - 0.94 to - 0.46). Reported rates of ventilator associated pneumonia (VAP) were lower in the NIV group. NIV weaning did not reduce overall hospital length of stay or long-term mortality. There were insufficient data to compare other adverse events and health-related quality of life.

CONCLUSIONS

The use of NIV in weaning from mechanical ventilation decreases hospital mortality, the incidence of VAP and ICU length of stay. NIV as a weaning strategy appears to be most beneficial in patients with COPD.

Validation of a new WIND classification compared to ICC classification for weaning outcome

Background

Although the WIND (Weaning according to a New Definition) classification based on duration of ventilation after the first separation attempt has been proposed, this new classification has not been tested in clinical practice. The objective of this cohort study was to evaluate the clinical relevance of WIND classification and its association with hospital mortality compared to the International Consensus Conference (ICC) classification.

Methods

All consecutive medical ICU patients who were mechanically ventilated for more than 24 h between July 2010 and September 2013 were prospectively registered. Patients were classified into simple, difficult, or prolonged weaning group according to ICC classification and Groups 1, 2, 3, or no weaning (NW) according to WIND classification.

Results

During the study period, a total of 1600 patients were eligible. These patients were classified by the WIND classification as follows: Group NW = 580 (36.3%), Group 1 = 617 (38.6%), Group 2 = 186 (11.6%), and Group 3 = 217 (13.6%). However, only 735 (45.9%) patients were classified by ICC classification as follows: simple weaning = 503 (68.4%), difficult weaning = 145 (19.7%), and prolonged weaning = 87 (11.8%). Clinical outcomes were significantly different across weaning groups by ICC classification and WIND classification. However, there were no statistical differences in successful weaning rate (96.6% vs. 95.2%) or hospital mortality (22.5% vs. 25.5%) between simple and difficult weaning groups by the ICC. Conversely, there were statistically significant differences in successful weaning rate (98.5% vs. 76.9%) and hospital mortality (21.2% vs. 33.9%) between Group 1 and Group 2 by WIND.

Conclusions

The WIND classification could be a better tool for predicting weaning outcomes than the ICC classification.

Electronic supplementary material

The online version of this article (10.1186/s13613-018-0461-z) contains supplementary material, which is available to authorized users.

Effect of Protocolized Weaning With Early Extubation to Noninvasive Ventilation vs Invasive Weaning on Time to Liberation From Mechanical Ventilation Among Patients With Respiratory Failure: The Breathe Randomized Clinical Trial

IMPORTANCE

In adults in whom weaning from invasive mechanical ventilation is difficult, noninvasive ventilation may facilitate early liberation, but there is uncertainty about its effectiveness in a general intensive care patient population.

OBJECTIVE

To investigate among patients with difficulty weaning the effects of protocolized weaning with early extubation to noninvasive ventilation on time to liberation from ventilation compared with protocolized invasive weaning.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, allocation-concealed, open-label, multicenter clinical trial enrolling patients between March 2013 and October 2016 from 41 intensive care units in the UK National Health Service. Follow-up continued until April 2017. Adults who received invasive mechanical ventilation for more than 48 hours and in whom a spontaneous breathing trial failed were enrolled.

INTERVENTIONS

Patients were randomized to receive either protocolized weaning via early extubation to noninvasive ventilation (n = 182) or protocolized standard weaning (continued invasive ventilation until successful spontaneous breathing trial, followed by extubation) (n = 182).

MAIN OUTCOMES AND MEASURES

Primary outcome was time from randomization to successful liberation from all forms of mechanical ventilation among survivors, measured in days, with the minimal clinically important difference defined as 1 day. Secondary outcomes were duration of invasive and total ventilation (days), reintubation or tracheostomy rates, and survival.

RESULTS

Among 364 randomized patients (mean age, 63.1 [SD, 14.8] years; 50.5% male), 319 were evaluable for the primary effectiveness outcome (41 died before liberation, 2 withdrew, and 2 were discharged with ongoing ventilation). The median time to liberation was 4.3 days in the noninvasive group vs 4.5 days in the invasive group (adjusted hazard ratio, 1.1; 95% CI, 0.89-1.40). Competing risk analysis accounting for deaths had a similar result (adjusted hazard ratio, 1.1; 95% CI, 0.86-1.34). The noninvasive group received less invasive ventilation (median, 1 day vs 4 days; incidence rate ratio, 0.6; 95% CI, 0.47-0.87) and fewer total ventilator days (median, 3 days vs 4 days; incidence rate ratio, 0.8; 95% CI, 0.62-1.0). There was no significant difference in reintubation, tracheostomy rates, or survival. Adverse events occurred in 45 patients (24.7%) in the noninvasive group compared with 47 (25.8%) in the invasive group.

CONCLUSIONS AND RELEVANCE

Among patients requiring mechanical ventilation in whom a spontaneous breathing trial had failed, early extubation to noninvasive ventilation did not shorten time to liberation from any ventilation.

TRIAL REGISTRATION

ISRCTN Identifier: ISRCTN15635197.

Impact of limb weakness on extubation failure after planned extubation in medical patients

BACKGROUND AND OBJECTIVE

Limb muscle weakness is associated with difficult weaning. However, there are limited data on extubation failure. The objective of this cohort study was to evaluate the association between limb muscle weakness according to the Medical Research Council (MRC) scale and extubation failure rates among patients in a medical intensive care unit (ICU).

METHODS

All consecutive medical ICU patients who were mechanically ventilated for more than 24 h and who were weaned according to protocol were prospectively registered, and limb muscle weakness was assessed using the MRC scale on the day of planned extubation. Association of limb muscle weakness with extubation failure within 48 h following planned extubation was evaluated with logistic regression analysis.

RESULTS

Over the study period, 377 consecutive patients underwent planned extubation through a standardized weaning process. Extubation failure occurred in 106 (28.1%) patients. Median scores on the MRC scale for four limbs were lower in patients with extubation failure (14, interquartile range (IQR) 12-16) than in patients without extubation failure (16, IQR 12-18; P = 0.024). In addition, extubation failure rates decreased significantly with increasing quartiles of MRC scores (P for trend <0.001). In multivariable analysis, MRC scores ≤10 points were independently associated with extubation failure within 48 h (adjusted OR 2.131, 95% CI: 1.071-4.240, P = 0.031).

CONCLUSION

Limb muscle weakness assessed on the day of extubation was found to be independently associated with higher extubation failure rates within 48 h following planned extubation in medical patients.

Weaning attempts, cough strength and albumin are independent risk factors of reintubation in medical patients

BACKGROUND

Reintubation is associated with increased hospital mortality. It is necessary to identify risk factors associated with reintubation.

METHODS

A prospective observational study was performed in a respiratory intensive care unit. Medical patients who successfully completed a spontaneous breathing trial (SBT) were enrolled. Before extubation, age, gender, vital signs, acute physiology and chronic health evaluation II score, SBT attempts, cough peak flow, arterial blood gas tests and albumin were recorded.

RESULTS

We enrolled 139 patients. Of these, 22 (15.8%) patients experienced reintubation within 72 hours after extubation. SBT attempts (odds ratio [OR] = 1.446, 95% confidence interval [CI]: 1.095-1.910), cough peak flow (OR = 0.975, 95% CI: 0.956-0.994) and albumin (OR = 0.847, 95% CI: 0.752-0.954) were independent risk factors for reintubation. In patients with 1, 2 and ≥3 SBT attempts, reintubation rates were 7.3%, 21.1% and 45.8%, respectively (P < .01). In patients with cough peak flow ≤60, 61-89 and ≥90 L/min, reintubation rates were 29.4%, 16.7% and 1.9%, respectively (P < .01). In patients with albumin ≤25, 26-30 and ≥31 g/L, reintubation rates were 32.4%, 11.1% and 9.8%, respectively (P = .01).

CONCLUSIONS

Multiple SBT attempts, weak cough and low albumin were associated with increased reintubation in medical patients. This study provides information for clinical practitioners in the consideration of patient extubation.

Who Dies after ICU Discharge? Retrospective Analysis of Prognostic Factors for In-Hospital Mortality of ICU Survivors

We investigated the causes of inpatient death after intensive care unit (ICU) discharge and determined predictors of in-hospital mortality in Korea. Using medical ICU registry data of Seoul National University Hospital, we performed a retrospective cohort study involving patients who were discharged alive from their first ICU admission with at least 24 hours of ICU length of stay (LOS). From January 2011 to August 2013, 723 patients were admitted to ICU and 383 patients were included. The estimated in-hospital mortality rate was 11.7% (45/383). The most common cause of death was respiratory failure (n = 25, 56%) followed by sepsis and cancer progression; the causes of hospital death and ICU admission were the same in 64% of all deaths; sudden unexpected deaths comprised about one-fifth of all deaths. In order to predict in-hospital mortality among ICU survivors, multivariate analysis identified presence of solid tumor (odds ratio [OR], 4.06; 95% confidence interval [CI], 2.01-8.2; P < 0.001), hematologic disease (OR, 4.75; 95% CI, 1.51-14.96; P = 0.013), Sequential Organ Failure Assessment (SOFA) score upon ICU admission (OR, 1.08; 95% CI, 0.99-1.17; P = 0.075), and hemoglobin (Hb) level (OR, 0.67; 95% CI, 0.52-0.86; P = 0.001) and platelet count (Plt) (OR, 0.99; 95% CI, 0.99-1.00; P = 0.033) upon ICU discharge as significant factors. In conclusion, a significant proportion of in-hospital mortality is predictable and those who die in hospital after ICU discharge tend to be severely-ill, with comorbidities of hematologic disease and solid tumor, and anemic and thrombocytopenic upon ICU discharge.

Nursing Strategies for Effective Weaning of the Critically Ill Mechanically Ventilated Patient

The risks imposed by mechanical ventilation can be mitigated by nurses' use of strategies that promote early but appropriate reduction of ventilatory support and timely extubation. Weaning from mechanical ventilation is confounded by the multiple impacts of critical illness on the body's systems. Effective weaning strategies that combine several interventions that optimize weaning readiness and assess readiness to wean, and use a weaning protocol in association with spontaneous breathing trials, are likely to reduce the requirement for mechanical ventilatory support in a timely manner. Weaning strategies should be reviewed and updated regularly to ensure congruence with the best available evidence.

Differences between prolonged weaning patients from medical and surgical intensive care units

BACKGROUND

It is not clear whether patients entering a specialized, interdisciplinary weaning unit from surgical or medical intensive care units (ICU) distinguish substantially. The purpose of the present study was to assess differences in patients with prolonged weaning being referred from surgical and medical ICU.

METHODS

Data collected from April 2013 to April 2014 was conducted for retrospective analysis. Mortality rates, demographic data, clinical, and microbial differences in 150 patients with prolonged weaning were assessed (80 surgical and 70 medical).

RESULTS

Surgical ICU referrals tended to be older (70.7 ± 11.3 vs. 67.3 ± 12.3, P = 0.051) and had fewer underlying pulmonary diseases (45% vs. 60%, P = 0.067). Sodium values at the time of referral to the weaning unit were significantly higher in surgical (147.1 ± 9.6) vs. medical (141.3 ± 6.7 mmol/l) patients (P < 0.001). Each 10-unit increase in sodium at the time of referral to the weaning unit was associated with a 2.5-day (95% CI -0.4, 5.4; P = 0.09) prolongation of stay in the weaning unit. Although significant differences in microbiological agents from tracheal aspiration were seen, the infection rate on the weaning unit was similar in both groups. There was no difference in weaning unit mortality between surgical and medical ICU patients (18% vs. 23%; P = 0.41).

CONCLUSION

Few differences were found between patients being referred to a specialized weaning unit from surgical vs. medical ICUs. Besides differences in microbiological characteristics of tracheal secretions, there were also differences in sodium levels, which appear to influence on treatment duration.

[Weaning from mechanical ventilation. Weaning categories and weaning concepts]

The international classification of three weaning categories (simple weaning, difficult weaning, prolonged weaning) has been modified in the German weaning guidelines: the group of prolonged weaning has been subclassified into weaning without noninvasive ventilation (NIV), weaning with NIV, if necessary with continuing NIV in the form of home mechanical ventilation, and weaning failure.Strategies to prevent prolonged weaning comprise daily interruption of sedation, daily screening of capability of spontaneous breathing by a spontaneous breathing trial (SBT) and early implementation of NIV instead of continuing invasive mechanical ventilation especially in hypercapnic patients. The comorbidity left heart failure plays a major role in weaning failure and need for re-intubation-in this case early diagnosis and if necessary modification of heart therapy are important.Specialised weaning-centres offer the option for successful weaning for about 50-60 % of patients declared as unweanable by usual intensive care units. A multimodal therapy concept with respiratory therapists, physiotherapists and speech therapy is necessary to reach this goal. In case of weaning failure a professional discharge management to invasive home mechanical ventilation is important. Competent care by physicians in the out-of-hospital area is restricted by the sectoral division of responsibility by the German health care system. Improvement in this area is urgently needed.

Ventilator Weaning and Spontaneous Breathing Trials; an Educational Review

The term "weaning" is used to describe the gradual process of decreasing ventilator support. It is estimated that 40% of the duration of mechanical ventilation is dedicated to the process of weaning. Spontaneous breathing trial (SBT) assesses the patient's ability to breathe while receiving minimal or no ventilator support. The collective task force in 2001 stated that the process of SBT and weaning should start by assessing whether the underlying cause of respiratory failure has been resolved or not. Weaning predictors are parameters that are intended to help clinicians predict whether weaning attempts will be successful or not. Although the international consensus conference in 2005 did not recommend their routine use for clinical decision making, researchers did not stop working in this area. In the present article, we review some of the recent studies about weaning predictors, criteria, procedure, as well as assessment for extubation a mechanically ventilated patient.

Impact of delirium on weaning from mechanical ventilation in medical patients

BACKGROUND AND OBJECTIVE

Delirium is an important predictor of negative clinical outcomes in intensive care unit (ICU), including prolonged mechanical ventilation (MV). However, delirium has not yet proven to be directly linked to weaning difficulties. The objective of this cohort study was to evaluate the association between delirium, as observed on the day of the weaning trial, and subsequent weaning outcomes in medical patients.

METHODS

This is a retrospective analysis with prospectively collected data on weaning from mechanical ventilation (MV) and delirium, as assessed by bedside ICU nurses using the Confusion Assessment Method for the ICU (CAM-ICU) between October 2011 and September 2013.

RESULTS

During the study period, a total of 393 patients with MV support underwent a spontaneous breathing trial (SBT) according to the standardized protocol. Of these patients, 160 (40.7%) were diagnosed with delirium on the day of the first SBT. Patients without delirium were more successfully extubated than those with delirium (81.5% vs 69.4%, P = 0.005). Delirium was found to be associated with final weaning outcomes, including difficult (OR 1.962, 95% CI 1.201-3.205) and prolonged weaning (OR 2.318, 95% CI 1.272-4.226) when simple weaning was used as a reference category. After adjusting for potential confounding factors, delirium was still significantly associated with difficult weaning (adjusted OR 2.073, 95% CI 1.124-3.822), but not with prolonged weaning (adjusted OR 2.001, 95% CI 0.875-4.575).

CONCLUSION

Delirium, as assessed by the CAM-ICU at the time of first weaning trial, was significantly associated with weaning difficulties in medical patients.

Strategies for weaning from mechanical ventilation: a state of the art review

Identification and adoption of strategies to promote timely and successful weaning from mechanical ventilation remain a research and quality improvement priority. The most important steps in the weaning process to prevent unnecessary prolongation of mechanical ventilation are timely recognition of both readiness to wean and readiness to extubate. Strategies shown to be effective in promoting timely weaning include weaning protocols and use of spontaneous breathing trials. This review explores various other strategies that also may promote timely and successful weaning including bundling of spontaneous breathing trials with sedation and delirium monitoring/management as well as early mobility, the use of automated weaning systems and modes that improve patient-ventilator interaction, mechanical insufflation-exsufflation as a weaning adjunct, early extubation to non-invasive ventilation and high flow humidified oxygen. As most critically ill patients requiring mechanical ventilation will tolerate extubation with minimal weaning, identification of strategies to improve management of those patients experiencing difficult and prolonged weaning should be a priority for clinical practice, quality improvement initiatives and weaning research.