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.

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.

Trends of in-hospital cardiac arrests in a single tertiary hospital with a mature rapid response system.

BACKGROUND: Most studies on rapid response system (RRS) have simply focused on its role and effectiveness in reducing in-hospital cardiac arrests (IHCAs) or hospital mortality, regardless of the predictability of IHCA. This study aimed to identify the characteristics of IHCAs including predictability of the IHCAs as our RRS matures for 10 years, to determine the best measure for RRS evaluation. METHODS: Data on all consecutive adult patients who experienced IHCA and received cardiopulmonary resuscitation in general wards between January 2010 and December 2019 were reviewed. IHCAs were classified into three groups: preventable IHCA (P-IHCA), non-preventable IHCA (NP-IHCA), and inevitable IHCA (I-IHCA). The annual changes of three groups of IHCAs were analyzed with Poisson regression models. RESULTS: Of a total of 800 IHCA patients, 149 (18.6%) had P-IHCA, 465 (58.1%) had NP-IHCA, and 186 (23.2%) had I-IHCA. The number of the RRS activations increased significantly from 1,164 in 2010 to 1,560 in 2019 (P = 0.009), and in-hospital mortality rate was significantly decreased from 9.20/1,000 patients in 2010 to 7.23/1000 patients in 2019 (P = 0.009). The trend for the overall IHCA rate was stable, from 0.77/1,000 patients in 2010 to 1.06/1,000 patients in 2019 (P = 0.929). However, while the incidence of NP-IHCA (P = 0.927) and I-IHCA (P = 0.421) was relatively unchanged over time, the incidence of P-IHCA decreased from 0.19/1,000 patients in 2010 to 0.12/1,000 patients in 2019 (P = 0.025). CONCLUSIONS: The incidence of P-IHCA could be a quality metric to measure the clinical outcomes of RRS implementation and maturation than overall IHCAs.

Automated alert and activation of medical emergency team using early warning score.

BACKGROUND: Timely recognition of warning signs from deteriorating patients and proper treatment are important in improving patient safety. In comparison to the traditional medical emergency team (MET) activation triggered by phone calls, automated activation of MET may minimize activation delays. However, limited data are available on the effects of automated activation systems on the time from derangement to MET activation and on clinical outcomes. The objective of this study was to determine the impact of an automated alert and activation system for MET on clinical outcomes in unselected hospitalized patients. METHODS: This is an observational study using prospectively collected data from consecutive patients managed by the MET at a university-affiliated, tertiary hospital from March 2013 to December 2019. The automated alert system automatically calculates the Modified Early Warning Score (MEWS) and subsequently activates MET when the MEWS score is 7 or higher, which was implemented since August 2016. The outcome measures of interest including hospital mortality in patients with MEWS of 7 or higher were compared between pre-implementation and post-implementation groups of the automated alert and activation system in the primary analysis. The association between the implementation of the system and hospital mortality was evaluated with logistic regression analysis. RESULTS: Of the 7678 patients who were managed by MET during the study period, 639 patients during the pre-implementation period and 957 patients during the post-implementation period were included in the primary analysis. MET calls due to abnormal physiological variables were more common during the pre-implementation period, while MET calls due to medical staff's worries or concern about the patient's condition were more common during the post-implementation period. The median time from deterioration to MET activation was significantly shortened in the post-implementation period compared to the pre-implementation period (34 min vs. 60 min, P < 0.001). In addition, unplanned ICU admission rates (41.2% vs. 71.8%, P < 0.001) was reduced during the post-implementation period. Hospital mortality was decreased after implementation of the automated alert system (27.2% vs. 38.5%, P < 0.001). The implementation of the automated alert and activation system was associated with decreased risk of death in the multivariable analysis (adjusted OR 0.73, 95% CI 0.56-0.90). CONCLUSIONS: After implementing an automated alert and activation system, the time from deterioration to MET activation was shortened and clinical outcomes were improved in hospitalized patients.

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.

Risk Factors for Early Medical Emergency Team Reactivation in Hospitalized Patients.

OBJECTIVES: The objective of this study was to investigate the risk factors for early medical emergency team reactivation (which is defined as repeated medical emergency team calls within 72 hr after the index medical emergency team call) in the patients remaining on the ward after index medical emergency team activation. DESIGN: Retrospective analysis with prospectively collected data. SETTING: A university-affiliated, tertiary referral hospital. PATIENTS: All consecutive patients over 18 years old who received medical emergency team intervention. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 3,989 cases eligible for analysis, 514 cases (12.9%) were classified into the reactivation group, with the remainder assigned to the nonreactivation group. In a multivariate analysis, chronic lung disease (odds ratio, 1.38; 95% CI, 1.03-1.86; p = 0.032), chronic liver disease (odds ratio, 1.44; 95% CI, 1.04-1.99; p = 0.028), activation due to bedside concern about overall deterioration without abnormal physiological variables (odds ratio, 1.30; 95% CI, 1.00-1.68; p = 0.049), advice or consultation only for medical emergency team intervention (odds ratio, 0.78; 95% CI, 0.63-0.97; p = 0.027), and discussion about treatment limitation (odds ratio, 0.39; 95% CI, 0.25-0.60; p < 0.001) were independently associated with medical emergency team reactivation. In the reactivation group, 249 patients (48.5%) were transferred to the ICU after repeated calls. Medical department admission (odds ratio, 1.68; 95% CI, 1.12-2.52; p = 0.012), chronic liver disease (odds ratio, 1.73; 95% CI, 1.07-2.79; p = 0.025), hematological malignancies (odds ratio, 1.63; 95% CI, 1.10-2.41; p = 0.015), and tachypnea at the end of medical emergency team were risk factors for medical emergency team reactivation requiring ICU admission. Discussion about treatment limitation (odds ratio, 0.14; 95% CI, 0.05-0.40; p < 0.001) was also associated with decreased risk of medical emergency team reactivation requiring ICU admission. CONCLUSIONS: An increased risk of early medical emergency team reactivation was associated with medical emergency team activation by bedside concern about overall deterioration and patients with chronic lung or liver disease.

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.

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.

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.

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

BACKGROUND: Although the weaning classification based on the difficulty and duration of the weaning process has been evaluated in the different type of intensive care units (ICUs), little is known about clinical outcomes and validity among the three groups in medical ICU. The objectives of this study were to evaluate the clinical relevance of weaning classification and its association with hospital mortality in a medical ICU with a protocol-based weaning program. METHODS: All consecutive patients admitted to the medical ICU and requiring mechanical ventilation (MV) for more than 24 hours were prospectively registered and screened for weaning readiness by a standardized weaning program between July 2010 and June 2013. Baseline characteristics and outcomes were compared across weaning classifications. RESULTS: During the study period, a total of 680 patients were weaned according to the standardized weaning protocol. Of these, 457 (67%) were classified as simple weaning, 136 (20%) as difficult weaning, and 87 (13%) as prolonged weaning. Ventilator-free days within 28 days decreased significantly from simple to difficult to prolonged weaning groups (P < 0.001, test for trends). In addition, reintubation within 48 hours after extubation (P < 0.001) and need for tracheostomy during the weaning process (P < 0.001) increased significantly across weaning groups. Finally, ICU (P < 0.001), post-ICU (P = 0.001), and hospital (P < 0.001) mortalities significantly increased across weaning groups. In a multiple logistic regression model, prolonged weaning but not difficult weaning was still independently associated with ICU (adjusted OR 8.265, 95% CI 3.484-19.605, P < 0.001), and post-ICU (adjusted OR 3.180, 95% CI 1.349-7.497, P = 0.005), and hospital (adjusted OR 5.528, 95% CI 2.801-10.910, P < 0.001) mortalities. CONCLUSIONS: Weaning classification based on the difficulty and duration of the weaning process may provide prognostic information for mechanically ventilated patients who undergo the weaning process.

Early impact of medical emergency team implementation in a country with limited medical resources: a before-and-after study.

PURPOSE: The purpose of the study was to determine whether earlier clinical intervention by a medical emergency team (MET) can improve patient outcomes in an Asian country. METHODS: A nonrandomized study was performed during two 6-month periods before and after the introduction of a MET. RESULTS: The rates of cardiac arrests and "potentially preventable" cardiac arrests were lower after MET introduction, but the differences did not reach statistical significance. There was a statistically significant decrease in the incidence of cardiac arrests in the first 3 months of the academic year (2.3 vs 1.2 per 1000 admissions, P = .012). Introduction of MET reduced the time interval from physiologic derangement meeting MET activation criteria to intensive care unit (ICU) admission ("derangement-to-ICU interval") (10.8 vs 6.3 hours, P < .001). Multivariate analysis revealed that the mortality of unplanned ICU admissions was independently associated with simplified acute physiology score 3 and "derangement-to-ICU interval." CONCLUSIONS: Introduction of a MET reduced the number of cardiac arrests in the general ward during the first 3 months of the academic year. Introduction of MET also decreased the "derangement-to-ICU interval," which was an independent predictor of survival in patients with unplanned ICU admissions. Therefore, MET introduction may lead to improved outcomes for hospitalized patients in a country with limited medical resources.