Effect of pressure support vs unassisted breathing through a tracheostomy collar on weaning duration in patients requiring prolonged mechanical ventilation: a randomized trial

Effect of Atypical Sleep EEG Patterns on Weaning From Prolonged Mechanical Ventilation

BACKGROUND

Approximately one-third of acute ICU patients display atypical sleep patterns that cannot be interpreted by using standard EEG criteria for sleep. Atypical sleep patterns have been associated with poor weaning outcomes in acute ICUs.

RESEARCH QUESTION

Do patients being weaned from prolonged mechanical ventilation experience atypical sleep EEG patterns, and are these patterns linked with weaning outcomes?

STUDY DESIGN AND METHODS

EEG power spectral analysis during wakefulness and overnight polysomnogram were performed on alert, nondelirious patients at a long-term acute care facility.

RESULTS

Forty-four patients had been ventilated for a median duration of 38 days at the time of the polysomnogram study. Eleven patients (25%) exhibited atypical sleep EEG. During wakefulness, relative EEG power spectral analysis revealed higher relative delta power in patients with atypical sleep than in patients with usual sleep (53% vs 41%; P < .001) and a higher slow-to-fast power ratio during wakefulness: 4.39 vs 2.17 (P < .001). Patients with atypical sleep displayed more subsyndromal delirium (36% vs 6%; P = .027) and less rapid eye movement sleep (4% vs 11% total sleep time; P < .02). Weaning failure was more common in the atypical sleep group than in the usual sleep group: 91% vs 45% (P = .013).

INTERPRETATION

This study provides the first evidence that patients in a long-term acute care facility being weaned from prolonged ventilation exhibit atypical sleep EEG patterns that are associated with weaning failure. Patients with atypical sleep EEG patterns had higher rates of subsyndromal delirium and slowing of the wakeful EEG, suggesting that these two findings represent a biological signal for brain dysfunction.

Prolonged Mechanical Ventilation, Weaning, and the Role of Tracheostomy

Depending on the definitional criteria used, approximately 5% to 10% of critical adults will require prolonged mechanical ventilation with longer-term outcomes that are worse than those ventilated for a shorter duration. Outcomes are affected by patient characteristics before critical illness and its severity but also by organizational characteristics and care models. Definitive trials of interventions to inform care activities, such as ventilator weaning, upper airway management, rehabilitation, and nutrition specific to the prolonged mechanical ventilation patient population, are lacking. A structured and individualized approach developed by the multiprofessional team in discussion with the patient and their family is warranted.

Ventilator Weaning in Prolonged Mechanical Ventilation-A Narrative Review

Patients requiring mechanical ventilation (MV) beyond 21 days, usually referred to as prolonged MV, represent a unique group with significant medical needs and a generally poor prognosis. Research suggests that approximately 10% of all MV patients will need prolonged ventilatory care, and that number will continue to rise. Although we have extensive knowledge of MV in the acute care setting, less is known about care in the post-ICU setting. More than 50% of patients who were deemed unweanable in the ICU will be liberated from MV in the post-acute setting. Prolonged MV also presents a challenge in care for medically complex, elderly, socioeconomically disadvantaged and marginalized individuals, usually at the end of their life. Patients and their families often rely on ventilator weaning facilities and skilled nursing homes for the continuation of care, but home ventilation is becoming more common. The focus of this review is to discuss recent advances in the weaning strategies in prolonged MV, present their outcomes and provide insight into the complexity of care.

Aerosol particle dispersion in spontaneous breathing training of oxygen delivery tracheostomized patients on prolonged mechanical ventilation

BACKGROUND

Tracheostomized patients undergoing liberation from mechanical ventilation (MV) are exposed to the ambient environment through humidified air, potentially heightening aerosol particle dispersion. This study was designed to evaluate the patterns of aerosol dispersion during spontaneous breathing trials in such patients weaning from prolonged MV.

METHODS

Particle Number Concentrations (PNC) at varying distances from tracheostomized patients in a specialized weaning unit were quantified using low-cost particle sensors, calibrated against a Condensation Particle Counter. Different oxygen delivery methods, including T-piece and collar mask both with the humidifier or with a small volume nebulizer (SVN), and simple collar mask, were employed. The PNC at various distances and across different oxygen devices were compared using the Kruskal-Wallis test.

RESULTS

Of nine patients receiving prolonged MV, five underwent major surgery, and eight were successfully weaned from ventilation. PNCs at distances ranging from 30 cm to 300 cm showed no significant disparity (H(4) = 8.993, p = 0.061). However, significant differences in PNC were noted among oxygen delivery methods, with Bonferroni-adjusted pairwise comparisons highlighting differences between T-piece or collar mask with SVN and other devices.

CONCLUSIONS

Aerosol dispersion within 300 cm of the patient was not significantly different, while the nebulization significantly enhances ambient aerosol dispersion in tracheostomized patients on prolonged MV.

Role of multidrug-resistant bacteria in weaning from invasive mechanical ventilation

BACKGROUND

Although multidrug-resistant bacteria (MDR) are common in patients undergoing prolonged weaning, there is little data on their impact on weaning and patient outcomes.

METHODS

This is a retrospective analysis of consecutive patients who underwent prolonged weaning and were at a university weaning centre from January 2018 to December 2020. The influence of MDR colonisation and infection on weaning success (category 3a and 3b), successful prolonged weaning from invasive mechanical ventilation (IMV) with or without the need for non-invasive ventilation (NIV) compared with category 3c (weaning failure 3cI or death 3cII) was investigated. The pathogen groups considered were: multidrug-resistant gram-negative bacteria (MDRGN), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp. (VRE).

RESULTS

A total of 206 patients were studied, of whom 91 (44.2%) showed evidence of MDR bacteria (32% VRE, 1.5% MRSA and 16% MDRGN), with 25 patients also meeting the criteria for MDR infection. 70.9% of the 206 patients were successfully weaned from IMV, 8.7% died. In 72.2% of cases, nosocomial pneumonia and other infections were the main cause of death. Patients with evidence of MDR (infection and colonisation) had a higher incidence of weaning failure than those without evidence of MDR (48% vs. 34.8% vs. 21.7%). In multivariate analyses, MDR infection (OR 4.9, p = 0.004) was an independent risk factor for weaning failure, along with male sex (OR 2.3, p = 0.025), Charlson Comorbidity Index (OR 1.2, p = 0.027), pH (OR 2.7, p < 0.001) and duration of IMV before admission (OR 1.01, p < 0.001). In addition, MDR infection was the only independent risk factor for death (category 3cII), (OR 6.66, p = 0.007).

CONCLUSION

Patients with MDR infection are significantly more likely to die during the weaning process. There is an urgent need to develop non-antibiotic approaches for the prevention and treatment of MDR infections as well as clinical research on antibiotic stewardship in prolonged weaning as well as in ICUs.

Automatic tube compensation for liberation from prolonged mechanical ventilation in tracheostomized patients: A retrospective analysis

BACKGROUND

To analyze the predictability of an automatic tube compensation (ATC) screening test compared with the conventional direct liberation test performed before continuous oxygen support for MV liberation.

METHODS

This retrospective study analyzed tracheostomized patients with prolonged MV in a weaning unit of a medical center in Taiwan. In March 2020, a four-day ATC test to screen patient eligibility for ventilator liberation was implemented, intended to replace the direct liberation test. We compared the predictive accuracy of these two screening methods on the relevant outcomes in the two years before and one year after the implementation of this policy.

RESULTS

Of the 403 cases, 246 (61%) and 157 (39%) received direct liberation and ATC screening tests, respectively. These two groups had similar outcomes: successful weaning upon leaving the Respiratory Care Center (RCC), success on day 100 of MV, success at hospital discharge, and in-hospital survival. Receiver operating characteristic curve analysis showed that the ATC screening test had better predictive ability than the direct liberation test for RCC weaning, discharge weaning, 100-day weaning, and in-hospital survival.

CONCLUSION

This closed-circuit ATC screening test before ventilator liberation is a feasible and valuable method for screening PMV patients undergoing ventilator liberation in the pandemic era. Its predictability for a comparison with the open-circuit oxygen test requires further investigation.

Managing the Chronically Ventilated Critically Ill Population

Advances in intensive care over the past few decades have significantly improved the chances of survival for patients with acute critical illness. However, this progress has also led to a growing population of patients who are dependent on intensive care therapies, including prolonged mechanical ventilation (PMV), after the initial acute period of critical illness. These patients are referred to as the "chronically critically ill" (CCI). CCI is a syndrome characterized by prolonged mechanical ventilation, myoneuropathies, neuroendocrine disorders, nutritional deficiencies, cognitive and psychiatric issues, and increased susceptibility to infections. It is associated with high morbidity and mortality as well as a significant increase in healthcare costs. In this article, we will review disease burden, outcomes, psychiatric effects, nutritional and ventilator weaning strategies as well as the role of palliative care for CCI with a specific focus on those requiring PMV.

Monitoring the performance of a dedicated weaning unit using risk-adjusted control charts for the weaning rate in prolonged mechanical ventilation

BACKGROUND

Weaning rate is an important quality indicator of care for patients with prolonged mechanical ventilation (PMV). However, diverse clinical characteristics often affect the measured rate. A risk-adjusted control chart may be beneficial for assessing the quality of care.

METHODS

We analyzed patients with PMV who were discharged between 2018 and 2020 from a dedicated weaning unit at a medical center. We generated a formula to estimate monthly weaning rates using multivariate logistic regression for the clinical, laboratory, and physiologic characteristics upon weaning unit admission in the first two years (Phase I). We then applied both multiplicative and additive models for adjusted p-charts, displayed in both non-segmented and segmented formats, to assess whether special cause variation existed.

RESULTS

A total of 737 patients were analyzed, including 503 in Phase I and 234 in Phase II, with average weaning rates of 59.4% and 60.3%, respectively. The p-chart of crude weaning rates did not show special cause variation. Ten variables from the regression analysis were selected for the formula to predict individual weaning probability and generate estimated weaning rates in Phases I and II. For risk-adjusted p-charts, both multiplicative and additive models showed similar findings and no special cause variation.

CONCLUSION

Risk-adjusted control charts generated using a combination of multivariate logistic regression and control chart-adjustment models may provide a feasible method to assess the quality of care in the setting of PMV with standard care protocols.

Bench Assessment of Work of Breathing During a Spontaneous Breathing Trial on Zero Pressure Support and Zero PEEP Compared to T-Piece

BACKGROUND

Analysis of observational data suggests that both a T-piece and zero pressure support ventilation (PSV) and zero PEEP impose work of breathing (WOB) during a spontaneous breathing trial (SBT) similar to what a patient experiences after extubation. The aim of our study was to compare the WOB imposed by the T-piece with zero PSV and zero PEEP. We also compared the difference in WOB when using zero PSV and zero PEEP on 3 different ventilators.

METHODS

This study was conducted by using a breathing simulator that simulated 3 lung models (ie, normal, moderate ARDS, and COPD). Three ventilators were used and set to zero PSV and zero PEEP. The outcome variable was WOB expressed as mJ/L of tidal volume.

RESULTS

An analysis of variance showed that WOB was statistically different between the T-piece and zero PSV and zero PEEP on all the ventilators (Servo-i, Servo-u, and Carescape R860). The absolute difference was lowest for the Carescape R860, which increased WOB by 5-6%, whereas the highest for Servo-u, which reduced the WOB by 15-21%.

CONCLUSIONS

Work may be imposed or reduced during spontaneous breathing on zero PSV and zero PEEP when compared to T-piece. The unpredictable nature of how zero PSV and zero PEEP behaves on different ventilators makes it an imprecise SBT modality in the context of assessing extubation readiness.

The effectiveness of pressure support ventilation and T-piece in differing duration among weaning patients: A systematic review and network meta-analysis

BACKGROUND

A spontaneous breathing trial (SBT) is recommended to help patients to liberate themselves from mechanical ventilation as soon as possible in the ICU. The respiratory workload in SBT, which depends on being with or without respiratory support and a specific time, is more accurate to reflect how much support the weaning patients need compared with only considering SBT technologies.

AIM

To compare and rank the effectiveness of different respiratory workloads during SBT via differing technologies (Pressure Support Ventilation and T-piece) and differing duration (30 and 120 min) in SBTs.

STUDY DESIGN

A comprehensive literature search was performed in six English electronic databases to identify eligible randomized controlled trials (RCTs) published before September 2020. The pooled risk ratio (RR) with 95% confidence interval (CI) was calculated by Markov chain Monte Carlo methods. A Bayesian network meta-analysis was conducted using "gemtc" version 0.8.2 of R software. Each intervention's ranking possibilities were calculated using the surface under the cumulative ranking analysis (SUCRA).

RESULTS

A total of nine RCTs including 3115 participants were eligible for this network meta-analysis involving four different commonly used SBT strategies and four outcomes. The only statistically significant difference was between Pressure Support Ventilation (PSV) 30 min and T-piece 120 min in the outcome of the rate of success in SBTs (RR = 0.91; 95% CI, 0.84-0.98). The cumulative rank probability showed that the rate of success in SBT from best to worst was PSV 30 min, PSV 120 min, T-piece 30 min and T-piece 120 min. PSV 30 min and PSV 120 min are more likely to have a higher rate of extubation (SUCRA values of 82.5% for 30 min PSV, 70.7% for 120 min PSV, 36.4% for T-piece 30 min, 10.4% for T-piece 120). Meanwhile, T-piece 120 min (SUCRA, 62.9%) and PSV 120 min (SUCRA, 60.9%) may result in lower reintubation rates, followed by T-piece 30 min (SUCRA, 41.8%) and PSV 30 min (SUCRA, 34.4%).

CONCLUSIONS AND RELEVANCE TO CLINICAL PRACTICE

In comprehensive consideration of four outcomes, regarding SBT strategies, 30-min PSV was superior in simple-to-wean patients. Besides, 120-min T-piece and 120-min PSV are more likely to achieve a lower reintubation rate. Thus, the impact of duration is more significant among patients who have a high risk of reintubation. It is still unclear whether the SBTs affect the outcome of mortality; further studies may need to explore the underlying mechanism.

Prolonged Mechanical Ventilation Following Coronary Artery Bypass Graft in Santiago De Cali, Colombia

Purpose

The purpose of this study was to describe factors associated with prolonged ventilatory support in subjects undergoing coronary artery bypass graft.

Patients and Methods

This was an analytical retrospective case-control study. Cases were defined as subjects requiring prolonged mechanical ventilation (>48 hours) following isolated coronary artery bypass graft. Subjects older than 18 years who had undergone surgery were included, while subjects with missing clinical record data, subjects in coma or subjects with prior cardiac surgery were excluded. Variables were measured at the three time points surrounding surgery.

Results

A total of 204 cases and 408 controls were included. The final logistic model showed an association between prolonged mechanical ventilation and the following presurgical variables: chronic obstructive pulmonary disease (OR 1.85; 95% CI: 1.06-3.23, p = 0.03) and chronic kidney disease (OR 1.90; 95% CI: -3.31; p = 0.02). The associated transurgical variable was the use of intra-aortic balloon pump (OR 3.63; 95% CI: 1.73-7.61, p = 0.00), and associated postsurgical variables were venous oxygen saturation <60% (OR 2.00; 95% CI: 1.18-3.40, p = 0.01), mediastinitis (OR 18.51; 95% CI: 4.06-84.40, p = 0.00), inotrope use (OR 2.82; 95% CI: 1.77-4.48, p = 0.00), pleural effusion requiring drainage (OR 3.57; 95% CI: 2.02-6.32, p = 0.00) and delirium (OR 3.45; 95% CI: 1.91-6.25, p = 0.00).

Conclusion

This study identifies factors associated with prolonged mechanical ventilation in subjects subject to coronary artery bypass graft over the presurgical, transurgical and postsurgical periods, identifying a new factor, delirium, for this type of population.

Incidence, causes, and predictors of unsuccessful decannulation following prolonged weaning

Background

Liberation from prolonged tracheostomy ventilation involves ventilator weaning and removal of the tracheal cannula (referred to as decannulation). This study evaluated the incidence, causes, and predictors of unsuccessful decannulation following prolonged weaning.

Methods

Observational retrospective cohort study of 532 prolonged mechanically ventilated, tracheotomized patients treated at a specialized weaning center between June 2013 and January 2021. We summarized the causes for unsuccessful decannulations and used a binary logistic regression analysis to derive and validate associated predictors.

Results

Failure to decannulate occurred in 216 patients (41%). The main causes were severe intensive care unit (ICU)-acquired dysphagia (64%), long-term ventilator dependence following weaning failure (41%), excessive respiratory secretions (12%), unconsciousness (4%), and airway obstruction (3%). Predictors of unsuccessful decannulation from any cause were age [odds ratio (OR) = 1.04 year^-1; 95% confidence interval (CI), 1.02-1.06; p < 0.01], body mass index [0.96 kg/m² (0.93-1.00); p = 0.027], Acute Physiology and Chronic Health Evaluation II (APACHE-II) score [1.05 (1.00-1.10); p = 0.036], pre-existing non-invasive home ventilation [3.57 (1.51-8.45); p < 0.01], percutaneous tracheostomies [0.49 (0.30-0.80); p < 0.01], neuromuscular diseases [4.28 (1.21-15.1); p = 0.024], and total mechanical ventilation duration [1.02 day^-1 (1.01-1.02); p < 0.01]. Regression models examined in subsets of patients with severe dysphagia and long-term ventilator dependence as the main reason for failure revealed little overlapping among predictors, which even showed opposite effects on the outcome. The application of non-invasive ventilation as a weaning technique contributed to successful decannulation in 96 of 221 (43%) long-term ventilator-dependent patients following weaning failure.

Conclusion

Failure to decannulate after prolonged weaning occurred in 41%, mainly resulting from persistent ICU-acquired dysphagia and long-term ventilator dependence following weaning failure, each associated with its own set of predictors.

Early prediction of hospital outcomes in patients tracheostomized for complex mechanical ventilation weaning

Background

Tracheostomy is often performed in the intensive care unit (ICU) when mechanical ventilation (MV) weaning is prolonged to facilitate daily care. Tracheostomized patients require important healthcare resources and have poor long-term prognosis after the ICU. However, data lacks regarding prediction of outcomes at hospital discharge. We looked for patients’ characteristics, ventilation parameters, sedation and analgesia use (pre-tracheostomy) that are associated with favorable and poor outcomes (post-tracheostomy) using univariate and multivariate logistic regressions.

Results

Eighty tracheostomized patients were included (28.8% women, 60 [52–71] years). Twenty-three (28.8%) patients were intubated for neurological reasons. Time from intubation to tracheostomy was 14.7 [10–20] days. Thirty patients (37.5%) had poor outcome (19 patients deceased and 11 still tracheostomized at hospital discharge). All patients discharged with tracheostomy (n = 11) were initially intubated for a neurological reason. In univariate logistic regressions, older age and higher body-mass index (BMI) were associated with poor outcome (OR 1.18 [1.07–1.32] and 1.04 [1.01–1.08], p < 0.001 and p = 0.025). No MV parameters were associated with poor outcome. In the multiple logistic regression model higher BMI and older age were also associated with poor outcome (OR 1.21 [1.09–1.36] and 1.04 [1.00–1.09], p < 0.001 and p = 0.046).

Conclusions

Hospital mortality of patients tracheostomized because of complex MV weaning was high. Patients intubated for neurological reasons were frequently discharged from the acute care hospital with tracheostomy in place. Both in univariate and multivariate logistic regressions, only BMI and older age were associated with poor outcome after tracheostomy for patients undergoing prolonged MV weaning.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01047-z.

Prevalence of Diaphragmatic Dysfunction in the Long-Term Acute Care Setting and Its Effects on Ventilator Weaning Outcomes: A Retrospective Cohort Study

OBJECTIVE

To determine the prevalence of undiagnosed diaphragmatic dysfunction in a long-term acute care hospital setting in patients on prolonged mechanical ventilation and its association with weaning outcomes.

DESIGN

This is a single-center, retrospective cohort study including 451 patients on prolonged mechanical ventilation admitted to a long-term acute care hospital facility between 2012 and 2017. Diaphragmatic dysfunction was assessed using fluoroscopy.

RESULTS

Three hundred nineteen patients on prolonged mechanical ventilation were assessed for diaphragmatic dysfunction. Nine patients were diagnosed with diaphragmatic dysfunction before admission. Eighty (72.7%) without diaphragmatic dysfunction were successfully weaned and 30 (27.3%) failed to wean, whereas 51 participants (31.9%) with diaphragmatic dysfunction were successfully weaned and 109 (68.1%) failed to wean (P < 0.001). When analyzing days to wean, the median was 13 days for those with no diaphragmatic dysfunction, 19 days with unilateral diaphragmatic dysfunction, and 28 days with bilateral diaphragmatic dysfunction (P < 0.001). Weaning success was not statistically associated with generalized neuromuscular disorders, age, sex, body mass index, smoking history, or diabetes.

CONCLUSIONS

Diaphragmatic dysfunction was found to be strongly associated with time to wean and weaning success in the long-term acute care hospital setting. Very few patients despite being on prolonged mechanical ventilation were diagnosed with diaphragmatic dysfunction before long-term acute care hospital admission. Given this information, early diagnosis of diaphragmatic dysfunction among prolonged mechanical ventilation patients in the long-term acute care hospital setting is paramount in preventing secondary complications associated with mechanical ventilation.

Outcomes of prolonged intensive care and rehabilitation at a specialized multidisciplinary center in Sweden

BACKGROUND

Specialized clinics may improve the outcome for patients with prolonged intensive care stays. Admission may depend on diagnosis, need of respiratory support and more. We report the results from a Swedish specialized center with a multidisciplinary team approach to continued intensive care and simultaneous rehabilitation regardless of patients' primary diagnosis or ventilator need.

METHODS

All patients admitted and discharged from 2015 to 2018 were included. Demographics, diagnoses, ventilatory support requirement, discharge destination and survival were retrieved from the center´s quality registry.

RESULTS

A total of 181 patients, mean age 61 ± 16 years, 64% men, were analyzed. A neurological diagnosis was the cause for hospitalization in 46% of patients. Of the 55 patients admitted to the center for weaning from mechanical ventilation, 89% were successfully weaned within a median of 25 (interquartile range (IQR) 16-45) days. Decannulation was intended in 117 patients of which 90% were successful within a median of 25 (IQR 13-43) days. Readmission to intensive care was 4%. Most patients were discharged to their home or to rehabilitation clinics with a lower level of care. In-clinic mortality was 3%. Survival beyond 1 and 2 years after discharge was 79% and 70%, respectively.

CONCLUSION

Patients with prolonged intensive care and complex medical needs treated at a specialized center in Sweden had weaning and decannulation rates comparable to or better than previously reported. Mortality was low, and most patients were discharged home or for further rehabilitation. This was achieved with a multidisciplinary team approach to continued intensive care and simultaneous rehabilitation.

Mechanical power normalized to lung-thorax compliance indicates weaning readiness in prolonged ventilated patients

Since critical respiratory muscle workload is a significant determinant of weaning failure, applied mechanical power (MP) during artificial ventilation may serve for readiness testing before proceeding on a spontaneous breathing trial (SBT). Secondary analysis of a prospective, observational study in 130 prolonged ventilated, tracheotomized patients. Calculated MP’s predictive SBT outcome performance was determined using the area under receiver operating characteristic curve (AUROC), measures derived from k-fold cross-validation (likelihood ratios, Matthew's correlation coefficient [MCC]), and a multivariable binary logistic regression model. Thirty (23.1%) patients failed the SBT, with absolute MP presenting poor discriminatory ability (MCC 0.26; AUROC 0.68, 95%CI [0.59‒0.75], p = 0.002), considerably improved when normalized to lung-thorax compliance (LTC_dyn-MP, MCC 0.37; AUROC 0.76, 95%CI [0.68‒0.83], p < 0.001) and mechanical ventilation P_aCO₂ (so-called power index of the respiratory system [PI_rs]: MCC 0.42; AUROC 0.81 [0.73‒0.87], p < 0.001). In the logistic regression analysis, PI_rs (OR 1.48 per 1000 cmH₂O²/min, 95%CI [1.24‒1.76], p < 0.001) and its components LTC_dyn-MP (1.25 per 1000 cmH₂O²/min, [1.06‒1.46], p < 0.001) and mechanical ventilation P_aCO₂ (1.17 [1.06‒1.28], p < 0.001) were independently related to SBT failure. MP normalized to respiratory system compliance may help identify prolonged mechanically ventilated patients ready for spontaneous breathing.

Noninvasive and invasive mechanical ventilation for neurologic disorders

Patients with acute neurologic injuries frequently require mechanical ventilation due to diminished airway protective reflexes, cardiopulmonary failure secondary to neurologic insults, or to facilitate gas exchange to precise targets. Mechanical ventilation enables tight control of oxygenation and carbon dioxide levels, enabling clinicians to modulate cerebral hemodynamics and intracranial pressure with the goal of minimizing secondary brain injury. In patients with acute spinal cord injuries, neuromuscular conditions, or diseases of the peripheral nerve, mechanical ventilation enables respiratory support under conditions of impending or established respiratory failure. Noninvasive ventilatory approaches may be carefully considered for certain disease conditions, including myasthenia gravis and amyotrophic lateral sclerosis, but may be inappropriate in patients with Guillain-Barré syndrome or when relevant contra-indications exist. With regard to discontinuing mechanical ventilation, considerable uncertainty persists about the best approach to wean patients, how to identify patients ready for extubation, and when to consider primary tracheostomy. Recent consensus guidelines highlight these and other knowledge gaps that are the focus of active research efforts. This chapter outlines important general principles to consider when initiating, titrating, and discontinuing mechanical ventilation in patients with acute neurologic injuries. Important disease-specific considerations are also reviewed where appropriate.

End-Expiratory Lung Volumes During Spontaneous Breathing Trials in Tracheostomized Subjects on Prolonged Mechanical Ventilation

BACKGROUND

The role of end-expiratory lung volume (EELV) during a spontaneous breathing trial (SBT) in patients who were tracheostomized and on prolonged mechanical ventilation is unclear. This study aimed to assess EELV during a 60-min SBT and its correlation with weaning success.

METHODS

Enrolled subjects admitted to a weaning unit were measured for EELV and relevant parameters before and after the SBT.

RESULTS

Of the 44 enrolled subjects, 29 (66%) were successfully liberated, defined as not needing mechanical ventilation for 5 d. The success group had fewer subjects with chronic kidney disease (41% vs 73%, P = .044), stronger mean ± SD maximum inspiratory pressure (41.6 ± 10.4 vs 34.1 ± 7.1 cm H₂O; P = .02) and mean ± SD maximum expiratory pressure (46.9 ± 11.7 vs 35.3 ± 16.9 cm H₂O; P = .01) versus the failure group. Toward the end of the SBT, the success group had a significant increase in the mean ± SD EELV (before vs after: 1,278 ± 744 vs 1,493 ± 867 mL; P = .040) and a decrease in the mean ± SD rapid shallow breathing index (83.8 ± 39.4 vs 66.3 ± 29.4; P = .02), whereas there were no significant changes in these 2 parameters in the failure group. The Cox regression analysis showed that, at the beginning of SBT, a greater difference between EELV with a PEEP of 0 cm H₂O and with a PEEP of 5 cm H₂O was significantly correlated to a higher likelihood of weaning success. Toward the end of the SBT, a greater EELV level at a PEEP of 0 cm H₂O was also correlated with weaning success. Also, the greater difference of EELV at a PEEP of 0 cm H₂O between the beginning and the end of the SBT was also correlated with a shorter duration to weaning success.

CONCLUSIONS

The change in EELV during a 60-min SBT may be of prognostic value for liberation from prolonged mechanical ventilation in patients who had a tracheostomy. Our findings suggest a model to understand the underlying mechanism of failure of liberation from mechanical ventilation in these patients.

Long-Term Acute Care Hospital Outcomes of Mechanically Ventilated Patients With Coronavirus Disease 2019

Supplemental Digital Content is available in the text.

OBJECTIVES:

To describe the clinical characteristics and outcomes of adult patients with coronavirus disease 2019 requiring weaning from prolonged mechanical ventilation.

DESIGN:

Observational cohort study of patients admitted to two long-term acute care hospitals from April 1, 2020, to March 31, 2021.

SETTING:

Two long-term acute care hospitals specialized in weaning from prolonged mechanical ventilation in the Chicagoland area, Illinois, United States.

PATIENTS:

Adult (≥ 18 yr old) ICU survivors of respiratory failure caused by severe acute respiratory syndrome coronavirus 2 pneumonia receiving prolonged mechanical ventilation.

INTERVENTIONS:

None.

MEASUREMENTS AND MAIN RESULTS:

During the study period, 158 consecutive patients were transferred to the long-term acute care hospitals for weaning from prolonged ventilation. Demographic, clinical, and laboratory data were collected and analyzed. Final date of follow-up was June 1, 2021. Prior to long-term acute care hospital transfer, median length of stay at the acute care hospital was 41.0 days and median number of ventilator days was 35. Median age was 60.0 years, 34.8% of patients were women, 91.8% had a least one comorbidity, most commonly hypertension (65.8%) and diabetes (53.2%). The percentage of weaning success was 70.9%. The median duration of successful weaning was 8 days. Mortality was 9.6%. As of June 1, 2021, 19.0% of patients had been discharged home, 70.3% had been discharged to other facilities, and 1.3% were still in the long-term acute care hospitals.

CONCLUSIONS:

Most patients with coronavirus disease 2019 transferred to two Chicago-area long-term acute care hospitals successfully weaned from prolonged mechanical ventilation.

Mechanical power normalized to lung-thorax compliance predicts prolonged ventilation weaning failure: a prospective study

Background

Mechanical power (MP) of artificial ventilation, the energy transferred to the respiratory system, is a chief determinant of adequate oxygenation and decarboxylation. Calculated MP, the product of applied airway pressure and minute ventilation, may serve as an estimate of respiratory muscle workload when switching to spontaneous breathing. The aim of the study was to assess MP’s discriminatory performance in predicting successful weaning from prolonged tracheostomy ventilation.

Methods

Prospective, observational study in 130 prolonged mechanically ventilated, tracheotomized patients in a specialized weaning center. Predictive weaning outcome ability of arterial blood gas analyses and indices derived from calculated MP at beginning and end of weaning was determined in terms of area under receiver operating characteristic curve (AUROC) and measures derived from k-fold cross-validation (likelihood ratios, diagnostic odds ratio, F₁ score, and Matthews correlation coefficient [MCC]).

Results

Forty-four (33.8%) patients experienced weaning failure. Absolute MP showed poor discrimination in predicting outcome; whereas specific MP (MP normalized to dynamic lung-thorax compliance, LTC_dyn-MP) had moderate diagnostic accuracy (MCC 0.38; AUROC 0.79, 95%CI [0.71‒0.86], p < 0.001), further improved by correction for corresponding mechanical ventilation P_aCO₂ (termed the power index of the respiratory system [PI_rs]: MCC 0.52; AUROC 0.86 [0.79‒0.92], p < 0.001). Diagnostic performance of MP indices increased over the course of weaning, with maximum accuracy immediately before completion (LTC_dyn-MP: MCC 0.49; AUROC 0.86 [0.78‒0.91], p < 0.001; PI_rs: MCC 0.68; AUROC 0.92 [0.86‒0.96], p < 0.001).

Conclusions

MP normalized to dynamic lung-thorax compliance, a surrogate for applied power per unit of ventilated lung volume, accurately discriminated between low and high risk for weaning failure following prolonged mechanical ventilation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01566-8.

High-Flow Oxygen Therapy in Tracheostomized Subjects With Prolonged Mechanical Ventilation: A Randomized Crossover Physiologic Study

BACKGROUND

High-flow oxygen therapy via tracheostomy (HFT) can be used in tracheostomized patients during ventilator disconnection. The physiologic effects of this technique are unknown. We hypothesized that HFT would reduce inspiratory effort and improve breathing pattern compared to conventional oxygen therapy via T-tube. This study aimed to evaluate the physiologic effects of HFT compared to conventional O₂ in patients with prolonged mechanical ventilation.

METHODS

A randomized crossover physiologic study was conducted in adult tracheostomized patients who experienced temporary periods of ventilator disconnection. Subjects were ventilated with pressure support ventilation (PSV) for 15 min and were then randomly assigned to HFT or conventional O₂ via T-tube for 30 min. After a washout period, subjects were switched to the other system. Esophageal pressure (P_es), breathing frequency, blood pressure, heart rate, [Formula: see text], and transcutaneously measured pressure of carbon dioxide ([Formula: see text]) were recorded. The primary outcome was inspiratory effort as determined by the simplified esophageal pressure-time product (sPTP_es). Secondary outcomes were P_es swing, breathing frequency, heart rate, mean arterial pressure, [Formula: see text], and [Formula: see text] between groups.

RESULTS

Twenty-two subjects were enrolled: sPTP_es per minute was significantly higher with HFT and conventional O₂ compared to PSV (153.5 ± 97.9, 163.5 ± 111.3, and 86.8 ± 51.1 cm H₂O × s/min, respectively, P = .001), but it was not different between HFT and conventional O₂ (P = .72). Breathing frequency increased significantly after switching from PSV to HFT and conventional O₂ (23 ± 4 vs 26 ± 6 and 23 ± 4 vs 27 ± 5 breaths/min, respectively, P = .001). [Formula: see text] was higher with conventional O₂ compared to HFT (P = .02). No differences in [Formula: see text], mean arterial pressure, or heart rate were observed between HFT and conventional O₂.

CONCLUSIONS

Inspiratory effort and breathing frequency increased significantly during unassisted breathing compared to PSV in tracheostomized subjects, but HFT via tracheostomy provided no measurable additional physiologic benefit compared to O₂ therapy via T-tube.

Inspiratory Muscle Training With an Electronic Resistive Loading Device Improves Prolonged Weaning Outcomes in a Randomized Controlled Trial

OBJECTIVES

To test if the use of an inspiratory muscle training program with an electronic resistive loading device is associated with benefits as to muscle strength, weaning, and survival in the ICU.

DESIGN

Prospective randomized controlled trial.

SETTINGS

Study conducted at the ICU of a Navy's hospital, Rio de Janeiro, Brazil, from January 2016 to September 2018.

PATIENTS

Tracheostomized patients (18-86 yr) on prolonged weaning.

INTERVENTIONS

Participants were assigned to inspiratory muscle training (intervention group) or a traditional T-piece protocol (control group). In the inspiratory muscle training group, participants underwent training with an electronic inspiratory training device (POWERbreathe K-5; Technologies Ltd, Birmingham, United Kingdom).

MEASUREMENTS AND MAIN RESULTS

Changes in respiratory muscle strength and rates of ICU survival and weaning success were compared between groups. Forty-eight participants in the inspiratory muscle training group and 53 ones in the control group were included in the final analysis. The inspiratory muscle training was associated with a substantially higher gain on muscle strength as assessed by the maximal inspiratory pressure (70.5 [51.0-82.5] vs -48.0 cm H2O [36.0-72.0 cm H2O]; p = 0.003) and the timed inspiratory effort index (1.56 [1.25-2.08] vs 0.99 cm H2O/s [0.65-1.71 cm H2O/s]; p = 0.001). Outcomes at the 60th day of ICU were significantly better in the intervention group regarding both survival (71.1% vs 48.9%; p = 0.030) and weaning success (74.8% vs 44.5%; p = 0.001).

CONCLUSIONS

The use of an inspiratory muscle training program with an electronic resistive loading device was associated with substantial muscle strength gain and positive impacts in two very relevant clinical outcomes: the rates of ICU survival and successful weaning.

Weaning from Mechanical Ventilator in a Long-term Acute Care Hospital: A Retrospective Analysis

Background:

Prolonged Mechanical Ventilation (PMV) is associated with a higher cost of care and increased morbidity and mortality. Patients requiring PMV are referred mostly to Long-Term Acute Care (LTAC) facilities.

Objective:

To determine if protocol-driven weaning from mechanical ventilator by Respiratory Therapist (RT) would result in quicker weaning from mechanical ventilation, cost-effectiveness, and decreased mortality.

Methods:

A retrospective case-control study was conducted that utilized protocol-driven ventilator weaning by respiratory therapist (RT) as a part of the Respiratory Disease Certification Program (RDCP).

Results:

51 patients on mechanical ventilation before initiation of protocol-based ventilator weaning formed the control group. 111 patients on mechanical ventilation after implementation of the protocol formed the study group. Time to wean from the mechanical ventilation before the implementation of protocol-driven weaning by RT was 16.76 +/- 18.91 days, while that after the implementation of protocol was 7.67 +/- 6.58 days (p < 0.0001). Mortality proportion in patients after implementation of protocol-based ventilator weaning was 0.21 as compared to 0.37 in the control group (p=0.0153). The daily cost of patient care for the LTAC while on mechanical ventilation was $2200/day per patient while it was $ 1400/day per patient while not on mechanical ventilation leading to significant cost savings.

Conclusion:

Protocol-driven liberation from mechanical ventilation in LTAC by RT can significantly decrease the duration of a mechanical ventilator, leading to decreased mortality and cost savings.

Tracheostomy in patients with COVID-19: predictors and clinical features

BACKGROUND

Around 20% of patients hospitalized for COVID-19 need mechanical ventilation (MV). MV may be prolonged, thus warranting tracheostomy.

METHODS

Observational cohort study enrolling patients admitted due to COVID-19. Demographic and clinical data at hospital and ICU admission were collected. The primary endpoint was to identify parameters associated with a need for tracheostomy; secondary endpoints were to analyze the clinical course of patients who needed tracheostomy.

RESULTS

118 patients were enrolled; 37 patients (31.5%) were transferred to ICU, of which 11 (29.72%) needed a tracheostomy due to prolonged MV. Sequential Organ Failure Assessment (SOFA) score at ICU admission (OR 0.65, 95% CI 0.47-0.92, p 0.015) was the only variable found to be associated with increased risk of the need for tracheostomy, with a cut-off point of 4.5 (sensitivity 0.72, specificity 0.73, positive predictive value 0.57 and negative predictive value 0.85). The main complications were nosocomial infection (100%), supraventricular cardiac arrhythmia (45.5%), agitation (54.5%), pulmonary thromboembolism (9.1%) and depression (9.1%). All patients presented with hypoalbuminemia and significant critical illness polyneuropathy.

CONCLUSION

SOFA at ICU admission is associated with an increased risk of tracheostomy in patients with COVID-19. Moreover, they present clinical features similar to those with chronic critical illness and suffer SARS-CoV-2-related complications.

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.

How to ventilate obstructive and asthmatic patients

Exacerbations are part of the natural history of chronic obstructive pulmonary disease and asthma. Severe exacerbations can cause acute respiratory failure, which may ultimately require mechanical ventilation. This review summarizes practical ventilator strategies for the management of patients with obstructive airway disease. Such strategies include non-invasive mechanical ventilation to prevent intubation, invasive mechanical ventilation, from the time of intubation to weaning, and strategies intended to prevent post-extubation acute respiratory failure. The role of tracheostomy, the long-term prognosis, and potential future adjunctive strategies are also discussed. Finally, the physiological background that underlies these strategies is detailed.

Kinetics of oxygen uptake during unassisted breathing trials in prolonged mechanical ventilation: a prospective pilot study

Few studies have investigated the measurement of oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂) in tracheostomized patients undergoing unassisted breathing trials (UBTs) for liberation from mechanical ventilation (MV). Using an open-circuit, breath-to-breath method, we continuously measured \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂ and relevant parameters during 120-min UBTs via a T-tube in 49 tracheostomized patients with prolonged MV, and calculated mean values in the first and last 5-min periods. Forty-one (84%) patients successfully completed the UBTs. The median \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂ increased significantly (from 235.8 to 298.2 ml/min; P = 0.025) in the failure group, but there was no significant change in the success group (from 223.1 to 221.6 ml/min; P = 0.505). In multivariate logistic regression analysis, an increase in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂ > 17% from the beginning period (odds ratio [OR] 0.084; 95% confidence interval [CI] 0.012–0.600; P = 0.014) and a peak inspiratory pressure greater than − 30 cmH₂O (OR 11.083; 95% CI 1.117–109.944; P = 0.04) were significantly associated with the success of 120-min UBT. A refined prediction model combining heart rate, energy expenditure, end-tidal CO₂ and oxygen equivalent showed a modest increase in the area under the receiver operating characteristic curve of 0.788 (P = 0.578) and lower Akaike information criterion score of 41.83 compared to the traditional prediction model including heart rate and respiratory rate for achieving 48 h of unassisted breathing. Our findings show the potential of monitoring \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\dot{\text{V}}}$$\end{document}V˙O₂ in the final phase of weaning in tracheostomized patients with prolonged MV.

Noninvasive Respiratory Management of Spinal Cord Injury

Intubated ventilator-dependent patients with high-level spinal cord injury can be managed without tracheostomy tubes provided that they have sufficient cognition to cooperate and that any required surgical procedures are completed and they are medically stable. Intubation for a month or more than extubation to continuous noninvasive ventilatory support (NVS) can be safer long term than resort to tracheotomy. Noninvasive ventilation (NIV) is not conventionally being used for ventilatory support. Noninvasive interfaces include mouthpieces, nasal and oronasal interfaces, and intermittent abdominal pressure ventilators. NIV/NVS should never been used without consideration of mechanical insufflation-exsufflation for airway secretion clearance.

Maximal expiratory pressure is associated with reinstitution of mechanical ventilation after successful unassisted breathing trials in tracheostomized patients with prolonged mechanical ventilation

Objective

Reinstitution of mechanical ventilation (MV) for tracheostomized patients after successful weaning may occur as the care setting changes from critical care to general care. We aimed to investigate the occurrence, consequence and associated factors of MV reinstitution.

Methods

We analyzed the clinical data and physiological measurements of tracheostomized patients with prolonged MV discharged from the weaning unit to general wards after successful weaning to compare between those with and without in-hospital MV reinstitution within 60 days.

Results

Of 454 patients successfully weaned, 116 (25.6%) reinstituted MV at general wards within 60 days; at hospital discharge, 42 (36.2%) of them were eventually liberated from MV, 51 (44.0%) remained MV dependent, and 33 (28.4%) died. Of the 338 patients without reinstitution within 60 days, only 3 (0.9%) were later reinstituted with MV before discharge (on day 67, 89 and 136 at general wards, respectively), and 322 (95.2%) were successfully weaned again at discharge, while 13 (3.8%) died. Patients with MV reinstitution had a significantly lower level of maximal expiratory pressure (P_Emax) before unassisted breathing trial compared to those without reinstitution. Multivariable Cox regression analysis showed fever at RCC discharge (hazard ratio [HR] 14.00, 95% confidence interval [CI] 3.2–61.9) chronic obstructive pulmonary disease (HR 2.37, 95% CI 1.34–4.18), renal replacement therapy at the ICU (HR 2.29, 95% CI 1.50–3.49) and extubation failure before tracheostomy (HR 1.76, 95% CI 1.18–2.63) were associated with increased risks of reinstitution, while P_Emax > 30 cmH₂O (HR 0.51, 95% CI 0.35–0.76) was associated with a decreased risk of reinstitution.

Conclusions

The reinstitution of MV at the general ward is significant, with poor outcomes. The P_Emax measured before unassisted breathing trial was significantly associated with the risk of reinstituting MV at the general wards.

Frequency of Screening for Weaning From Mechanical Ventilation: Two Contemporaneous Proof-of-Principle Randomized Controlled Trials

OBJECTIVES

It is unknown whether more frequent screening of invasively ventilated patients, identifies patients earlier for a spontaneous breathing trial, and shortens the duration of ventilation. We assessed the feasibility of conducting a large trial to evaluate screening frequency in critically ill adults in the North American context.

DESIGN

We conducted two contemporaneous, multicenter, pilot, randomized controlled trials (the LibeRation from MEchanicaL VEntilAtion and ScrEening Frequency [RELEASE] and Screening Elderly PatieNts For InclusiOn in a Weaning [SENIOR] trials) to address concerns regarding the potential for higher enrollment, fewer adverse events, and better outcomes in younger patients.

SETTING

Ten and 11 ICUs in Canada, respectively.

PATIENTS

Parallel trials of younger (RELEASE < 65 yr) and older (SENIOR ≥ 65 yr) critically ill adults invasively ventilated for at least 24 hours.

INTERVENTIONS

Each trial compared once daily screening to "at least twice daily" screening led by respiratory therapists.

MEASUREMENTS AND MAIN RESULTS

In both trials, we evaluated recruitment (aim: 1-2 patients/month/ICU) and consent rates, reasons for trial exclusion, protocol adherence (target: ≥ 80%), crossovers (aim: ≤ 10%), and the effect of the alternative screening frequencies on adverse events and clinical outcomes. We included 155 patients (53 patients [23 once daily, 30 at least twice daily] in RELEASE and 102 patients [54 once daily, 48 at least twice daily] in SENIOR). Between trials, we found similar recruitment rates (1.32 and 1.26 patients/month/ICU) and reasons for trial exclusion, high consent and protocol adherence rates (> 92%), infrequent crossovers, and few adverse events. Although underpowered, at least twice daily screening was associated with a nonsignificantly faster time to successful extubation and more successful extubations but significantly increased use of noninvasive ventilation in both trials combined.

CONCLUSIONS

Similar recruitment and consent rates, few adverse events, and comparable outcomes in younger and older patients support conduct of a single large trial in North American ICUs assessing the net clinical benefits associated with more frequent screening.

Prophylactic noninvasive positive pressure ventilation in the weaning of difficult-weaning tracheotomy patients

Background

Prophylactic noninvasive positive pressure ventilation (NPPV) reduces reintubation in endotracheal intubation patients. However, the efficacy of using the prophylactic NPPV in the weaning of tracheotomy patients is unclear.

Methods

We performed prophylactic NPPV in 11 tracheotomy patients who passed a spontaneous breathing trial (SBT), removed the tracheotomy tube, and closed the incision (intervention group). We matched another 11 tracheotomy patients who also passed an SBT but weaning and removing of tracheotomy tube were managed as conventional methods (control group).

Results

Patients in the control group had reinstitution of mechanical ventilation 36 times after the initial SBT success. Compared with the control group, the interventional group had fewer weaning days (3.0±2.1 vs. 11.3±9.2, P=0.01) from initial SBT success to successful weaning and shorter intensive care unit (ICU) length of stay (11.6±4.2 vs. 20.3±11.6, P=0.03) after initial SBT success. The interventional group had lower nosocomial pneumonia rates after initial SBT success (0/11 vs. 2/11), lower ICU mortality (0/11 vs. 2/11), lower hospital mortality (0/11 vs. 3/11), and higher successful weaning rate (11/11 vs. 8/11), but it didn’t reach significant difference. Also, there was no significant difference between groups in total duration of ventilation (25.5±13.3 vs. 34.7±24.2 days), hospital stay after initial SBT success (24.0±22.3 vs. 37.4±31.3 days), total ICU stay (35.7±15.3 vs. 45.0±29.5 days), and total hospital stay (48.7±33.1 vs. 68.6±52.6 days).

Conclusions

Prophylactic NPPV may be useful to accelerate weaning, and shorten ICU stay after initial SBT success in tracheotomy patients.

Long-Term Outcome after Prolonged Mechanical Ventilation. A Long-Term Acute-Care Hospital Study

Rationale: Patients managed at a long-term acute-care hospital (LTACH) for weaning from prolonged mechanical ventilation are at risk for profound muscle weakness and disability. Objectives: To investigate effects of prolonged ventilation on survival, muscle function, and its impact on quality of life at 6 and 12 months after LTACH discharge. Methods: This was a prospective, longitudinal study conducted in 315 patients being weaned from prolonged ventilation at an LTACH. Measurements and Main Results: At discharge, 53.7% of patients were detached from the ventilator and 1-year survival was 66.9%. On enrollment, maximum inspiratory pressure (Pi_max) was 41.3 (95% confidence interval, 39.4-43.2) cm H₂O (53.1% predicted), whereas handgrip strength was 16.4 (95% confidence interval, 14.4-18.7) kPa (21.5% predicted). At discharge, Pi_max did not change, whereas handgrip strength increased by 34.8% (P < 0.001). Between discharge and 6 months, handgrip strength increased 6.2 times more than did Pi_max. Between discharge and 6 months, Katz activities-of-daily-living summary score improved by 64.4%; improvement in Katz summary score was related to improvement in handgrip strength (r = -0.51; P < 0.001). By 12 months, physical summary score and mental summary score of 36-item Short-Form Survey returned to preillness values. When asked, 84.7% of survivors indicated willingness to undergo mechanical ventilation again. Conclusions: Among patients receiving prolonged mechanical ventilation at an LTACH, 53.7% were detached from the ventilator at discharge and 1-year survival was 66.9%. Respiratory strength was well maintained, whereas peripheral strength was severely impaired throughout hospitalization. Six months after discharge, improvement in muscle function enabled patients to perform daily activities, and 84.7% indicated willingness to undergo mechanical ventilation again.

Variables predicting weaning outcome in prolonged mechanically ventilated tracheotomized patients: a retrospective study

Background

Several studies have assessed predictors of weaning and extubation outcome in short-term mechanically ventilated patients, but there are only few studies on predictors of weaning from prolonged mechanical ventilation.

Methods

Retrospective, single-center, observational study at a specialized national weaning center in Germany. Patients’ medical records were reviewed to obtain data on demographics, comorbidities, respiratory indices, and the result of a prospectively documented, standardized spontaneous breathing trial (SBT) upon admission to the weaning center. Respiratory indices assessed were the ventilatory ratio (VR) and parameters derived from calculated mechanical power (MP). Predictors associated with failure of prolonged weaning and failure of the SBT were assessed using a binary logistic regression model.

Results

A total of 263 prolonged mechanically ventilated, tracheotomized patients, treated over a 5-year period were analyzed. After 3 weeks of mechanical ventilation, patients with unsuccessful weaning failed a SBT more frequently and showed significantly increased values for inspiratory positive airway pressure, driving pressure, VR, absolute MP, and MP normalized to predicted body weight and dynamic lung-thorax compliance (LTC-MP). In the logistic regression analyses, variables independently correlated with weaning failure were female gender (adjusted odds ratio 0.532 [95% CI 0.291–0.973]; p = 0.040), obesity (body mass index ≥ 30 kg/m²) (2.595 [1.210–5.562]; p = 0.014), COPD (3.209 [1.563–6.589]; p = 0.002), LTC-MP (3.470 [1.067–11.284]; p = 0.039), P_aCO₂ on mechanical ventilation (1.101 [95% CI 1.034–1.173]; p = 0.003), and failure of the SBT (4.702 [2.250–9.825]; p < 0.001). In addition, female gender (0.401 [0.216–0.745]; p = 0.004), LTC-MP (3.017 [1.027–8.862]; p = 0.046), and P_aCO₂ on mechanical ventilation (1.157 [1.083–1.235]; p < 0.001) were independent risk factors for an unsuccessful SBT.

Conclusions

In the present study, the derived predictors of weaning point to a crucial role of the workload imposed on respiratory muscles during spontaneous breathing. Mechanical power normalized to lung-thorax compliance was independently correlated with weaning outcome and may identify patients at high risk for weaning failure.

Anemia and red blood cell transfusion practice in prolonged mechanically ventilated patients admitted to a specialized weaning center: an observational study

Background

The impact of anemia and red blood cell (RBC) transfusion on weaning from mechanical ventilation is not known. In theory, transfusions could facilitate liberation from the ventilator by improving oxygen transport capacity. In contrast, retrospective studies of critically ill patients showed a positive correlation of transfusions with prolonged mechanical ventilation, increased mortality rates, and increased risk of nosocomial infections, which in turn could adversely affect weaning outcome.

Methods

Retrospective, observational study on prolonged mechanically ventilated, tracheotomized patients (n = 378), admitted to a national weaning center over a 5 year period. Medical records were reviewed to obtain data on patients’ demographics, comorbidities, blood counts, transfusions, weaning outcome, and nosocomial infections, defined according to the criteria of the U.S. Centers for Disease Control and Prevention. The impact of RBC transfusion on outcome measures was assessed using regression models.

Results

Ninety-eight percent of all patients showed anemia on admission to the weaning center. Transfused and non-transfused patients differed significantly regarding disease severity and comorbidities. In multivariate analyses, RBC transfusion, but not mean hemoglobin concentration in the course of weaning, was independently correlated with weaning duration (adjusted β 12.386, 95% CI 9.335–15.436; p <  0.001) and hospital length of stay (adjusted β 16.116, 95% CI 8.925–23.306; p <  0.001); there was also a trend toward increased hospital mortality (adjusted odds ratio [OR] 2.050, 95% CI 0.995–4.224; p = 0.052), but there was no independent correlation with weaning outcome or nosocomial infections. In contrast, hemoglobin level on the day of admission to the weaning center was independently associated with hospital mortality (adjusted OR 0.956, 95% CI 0.924–0.989; p = 0.010), appearing significantly elevated at values below 8.5 g/dl (AUC 0.670, 95% CI 0.593–0.747; p <  0.001).

Conclusions

A high percentage of prolonged mechanically ventilated patients showed anemia on admission to the weaning center. RBC transfusion was independently correlated with worse outcomes. Since transfused patients differed significantly regarding their clinical characteristics and comorbidities, RBC transfusion might be an indicator of disease severity rather than directly impacting patient prognosis.

Physiologic Basis of Mechanical Ventilation

The primary purpose of mechanical ventilation is to decrease work of breathing. Achieving this goal requires that cycling of the ventilator be carefully aligned with the intrinsic rhythm of a patient's respiratory center output. Problems arise at the point of ventilator triggering, post-trigger inflation, and inspiration-expiration switchover. Careful, iterative adjustments of ventilator settings are required to minimize work of breathing. Use of protocols for the selection of ventilator settings can lead to complications (including alveolar overdistention) and risk of death. Because complications are axiomatic to mechanical ventilation, it should be discontinued at the earliest possible time. To shorten ventilator time, the critical step is to screen for weanability through use of weaning predictor tests. Use of T-tube trials circumvents the impossibility of estimating patient work of breathing during pressure support. Before extubation, patients should demonstrate the ability to breathe successfully in the absence of pressure support and positive end-expiratory pressure.

Mortality study in patients at weaning from mechanical ventilation

OBJECTIVE

To explain mortality in the ICU and in hospital among patients subjected to invasive mechanical ventilation.

DESIGN

A prospective, 9-month observational cohort study was carried out.

SETTING

A Department of Intensive Care Medicine.

PATIENTS

Consecutive patients requiring invasive mechanical ventilation were followed-up on until hospital discharge or death.

INTERVENTIONS

None.

INTEREST VARIABLES

Date of admission, day of first spontaneous breathing test, length of mechanical ventilation, final extubation date, days in ICU, days in hospital or discharge from ICU, SAPS-3 score, WIND study classification, day of death, hospital discharge.

RESULTS

There were 266 patients: 40 in group 0 of the WIND classification (15%; 95% CI 11-20%); 166 in group 1 (62%; 95% CI 56-68%); 38 in group 2 (14%; 95% CI 11-19%); and 22 in group 3 (8%; 95% CI 6-12%. Logistic regression analysis showed group 3 to have the highest hospital mortality (group 3 vs. group 1; odds ratio 4.0; 95% CI 1.5-10.8; P=.007). However, Cox regression analysis showed no significant differences (hazard ratio group 3 vs. group 1, 1.6; 95% CI 0.7-3.4; P=ns).

CONCLUSION

In our study, considering exposure time, the probability of mortality was the same among the 3 different groups of patients with at least one spontaneous breathing test.

Alternative Modes of Mechanical Ventilation

Modern mechanical ventilators are more complex than those first developed in the 1950s. Newer ventilation modes can be difficult to understand and implement clinically, although they provide more treatment options than traditional modes. These newer modes, which can be considered alternative or nontraditional, generally are classified as either volume controlled or pressure controlled. Dual-control modes incorporate qualities of pressure-controlled and volume-controlled modes. Some ventilation modes provide variable ventilatory support depending on patient effort and may be classified as closed-loop ventilation modes. Alternative modes of ventilation are tools for lung protection, alveolar recruitment, and ventilator liberation. Understanding the function and application of these alternative modes prior to implementation is essential and is most beneficial for the patient.

Patient and Family Centered Actionable Processes of Care and Performance Measures for Persistent and Chronic Critical Illness: A Systematic Review

Supplemental Digital Content is available in the text.

To identify actionable processes of care, quality indicators, or performance measures and their evidence base relevant to patients with persistent or chronic critical illness and their family members including themes relating to patient/family experience.

Predictors of prolonged mechanical ventilation in patients admitted to intensive care units: A systematic review

OBJECTIVE

Although intensive care medicine has evidenced a significant growth in recent decades, the number of patients requiring prolonged mechanical ventilation (PMV) still represents a considerable burden on health-care expenditure. The prediction of the need for PMV seems to provide a plausible cost-effective intervention. The objective of this study is to systematically review the predictors of the need for PMV of adult patients admitted to intensive care units (ICUs) due to medical and surgical needs.

METHODS

We conducted a systematic search on three online databases (PubMed, Embase, and MEDLINE) till February 20, 2019. The search process employed several combinations of specific keywords and Boolean operators.

RESULTS

A total of 15 articles were included in the study. Based on pooling the outcomes of odds ratios (ORs) and their respective 95% confidence intervals (CIs) as reported from logistic regression analyses, the pooled PMV incidence in 8220 patients (69.59% males) was 17.67 cases per 100 ICU admissions (95% CI 13.69-21.65). We could not conduct a meta-analysis of ORs and 95% CIs due to the significant heterogeneity observed between the included studies (P < 0.001, I2 = 97%). Pre-operative/preadmission kidney dysfunction and chronic obstructive pulmonary disease were the most significant independent predictors of the need for PMV. Following cardiac surgeries, repeated or emergency surgery, prolonged cardiopulmonary bypass time, and the need for blood transfusion were predictors of the need for PMV.

CONCLUSION

Within the study limitations, several predictors were identified, which could be further investigated using a unified PMV definition. Successful prediction of the need for PMV would assist clinicians in identifying and adjusting a "weaning strategy" as well as improving patient care to reduce morbidity. Furthermore, establishing specialized weaning units could be warranted based on PMV incidence and prediction in the local settings.

Score for Predicting Ventilator Weaning Duration in Patients With Tracheostomies

BACKGROUND

Factors affecting the timing of ventilator liberation among patients requiring prolonged mechanical ventilation (≥21 consecutive days) are poorly understood. After tracheostomy placement, ventilator liberation typically involves daily reductions in ventilator support as patients regain the capacity to breathe independently.

OBJECTIVES

To determine the association between ventilator requirements on the day after tracheostomy placement and subsequent weaning duration.

METHODS

Retrospective review of medical records of adults with tracheostomies treated at an academic medical center from 2011 to 2015. A new ventilator independence score based on ventilator settings on the day after tracheostomy was developed. Scores range from 0% to 100%; higher scores reflect greater levels of unassisted breathing for a greater proportion of the day. A multi-variable competing-risk survival regression model was used to determine the association between the ventilator independence score and time from tracheostomy placement to ventilator liberation.

RESULTS

Of 372 patients, 72% were liberated from mechanical ventilation. The ventilator independence score measured on the day after tracheostomy placement had an area under the receiver operating characteristic curve value of 0.71 (95% CI, 0.65-0.76) for differentiating patients who were liberated within the next 14 days from those who were not. Median time from tracheostomy placement to ventilator liberation was 41 days for patients with a score of 0%, 20 days for scores between 0% and 50%, 15 days for scores between 50% and 75%, and 10 days for scores between 75% and 100%.

CONCLUSIONS

A score derived from ventilator settings may help clinicians predict the timing of ventilator liberation in patients requiring prolonged mechanical ventilation.

Inspiratory Muscle Training with Isokinetic Device to Help Ventilatory Weaning in a Patient with Guillain-Barré Syndrome by Zika Virus

Zika is an arbovirus infection mainly transmitted by the mosquito Aedes aegypti. In 2016, the burden of Zika epidemic in Brazil was significant. Patients affected by Zika virus can develop Guillain-Barré syndrome, evolving to muscle respiratory failure requiring mechanical ventilation. In this setting, delayed recovery of the muscle weakness can result in prolonged weaning, a condition that by itself is related to a high mortality rate. The study is reporting a case of a patient with Zika and Guillain-Barré syndrome who underwent an inspiratory muscle training program starting after twenty-five days of mechanical ventilation and guided by serial measurements of the timed inspiratory effort (TIE) index. The patient was successfully weaned in two weeks and discharged from the hospital 30 days after extubation.

Pressure-support ventilation or T-piece spontaneous breathing trials for patients with chronic obstructive pulmonary disease - A randomized controlled trial

Background

Little is known about the best strategy for weaning patients with chronic obstructive pulmonary disease (COPD) from mechanical ventilation. Spontaneous breathing trials (SBT) using a T-piece or pressure-support ventilation (PSV) have a central role in this process. Our aim was to compare T-piece and PSV SBTs according to the duration of mechanical ventilation (MV) in patients with COPD.

Methods

Patients with COPD who had at least 48 hours of invasive MV support were randomized to 30 minutes of T-piece or PSV at 10 cm H₂O after being considered able to undergo a SBT. All patients were preemptively connected to non-invasive ventilation after extubation. Tracheostomized patients were excluded. The primary outcome was total invasive MV duration. Time to liberation from MV was assessed as secondary outcome.

Results

Between 2012 and 2016, 190 patients were randomized to T-piece (99) or PSV (91) groups. Extubation at first SBT was achieved in 78% of patients. The mean total MV duration was 10.82 ± 9.1 days for the T-piece group and 7.31 ± 4.9 days for the PSV group (p < 0.001); however, the pre-SBT duration also differed (7.35 ± 3.9 and 5.84 ± 3.3, respectively; p = 0.002). The time to liberation was 8.36 ± 11.04 days for the T-piece group and 4.06 ± 4.94 for the PSV group (univariate mean ratio = 2.06 [1.29–3.27], p = 0.003) for the subgroup of patients with difficult or prolonged weaning. The study group was independently associated with the time to liberation in this subgroup.

Conclusions

The SBT technique did not influence MV duration for patients with COPD. For the difficult/prolonged weaning subgroup, the T-piece may be associated with a longer time to liberation, although this should be clarified by further studies.

Trial registration

ClinicalTrials.gov NCT01464567, at November 3, 2011.

Inspiratory muscle training for intensive care patients: A multidisciplinary practical guide for clinicians

OBJECTIVES

To describe a multidisciplinary approach to inspiratory muscle training (IMT) for patients in the intensive care unit (ICU).

BACKGROUND

Inspiratory muscle weakness is a known consequence of prolonged mechanical ventilation, and there is emerging evidence that specific IMT can ameliorate this weakness. However, IMT is not yet standard practice in many ICUs, possibly because of the wide variety of methods reported and a lack of published practical guidelines. While the optimal parameters for IMT are yet to be established, we share our detailed methodology which has been shown to be safe in selected ventilator-dependent patients and is the only approach which has been shown to increase quality of life in ICU patients.

METHODS

Patients who have experienced invasive mechanical ventilation for at least 7 days can commence IMT in either the ventilator-dependent phase or when weaned from mechanical ventilation. Intensity should be prescribed based on maximum inspiratory pressure, which is measurable through the tracheostomy or endotracheal tube via the ventilator or a respiratory pressure meter. Using a removable threshold device, we recommend high-intensity training (5 sets of 6 breaths at a minimum of 50% of maximum inspiratory pressure) performed once per day, supervised by the physiotherapist, with intensity increased daily such that patients can only just complete the 6th breath in each set.

RESULTS

Using this high-intensity approach, IMT is likely to improve not only inspiratory muscle strength but also quality of life in patients recently weaned from mechanical ventilation of 7 days' duration or longer. Effective IMT requires a multidisciplinary approach to maximise feasibility, with doctors, nurses, and therapists working closely to optimise conditions for successful IMT.

CONCLUSIONS

This multidisciplinary approach to implement IMT in ICU patients should assist clinicians in translating best-available evidence into practice, with the potential to enhance patient recovery.

Variation in mortality rates after admission to long-term acute care hospitals for ventilator weaning

PURPOSE

We sought to examine variation in long-term acute care hospital (LTACH) quality based on 90-day in-hospital mortality for patients admitted for weaning from mechanical ventilation.

METHODS

We developed an administrative risk-adjustment model using data from Medicare claims. We validated the administrative model against a clinical model using data from LTACHs participating in a 2002 to 2003 clinical registry. We then used our validated administrative model to assess national variation in 90-day in-hospital mortality rates in LTACHs from 2013.

RESULTS

The administrative risk-adjustment model was derived using data from 9447 patients admitted to 221 LTACHs in 2003. The model had good discrimination (C statistic=0.72) and calibration. Compared to a clinically derived model using data from 1163 patients admitted to 14 LTACHs, the administrative model generated similar performance estimates. National variation in risk-adjusted mortality was assessed using data from 20,453 patients admitted to 380 LTACHs in 2013. LTACH-specific risk-adjusted mortality rates varied from 8.4% to 48.1% (median: 24.2%, interquartile range: 19.7%-30.7%).

CONCLUSIONS

LTACHs vary widely in mortality rates, underscoring the need to better understand the sources of this variation and improve the quality of care for patients requiring long-term ventilator weaning.