Ventilator Weaning and Discontinuation Practices for Critically Ill Patients.

Importance: Although most critically ill patients receive invasive mechanical ventilation (IMV), few studies have characterized how IMV is discontinued in practice. Objective: To describe practice variation in IMV discontinuation internationally, associations between initial discontinuation events and outcomes, and factors associated with the use of select discontinuation strategies and failed initial spontaneous breathing trials (SBTs). Design, Setting, and Participants: Prospective, multinational, observational study of critically ill adults who received IMV for at least 24 hours from 142 intensive care units (ICUs) in 19 countries within 6 regions (27 in Canada, 23 in India, 22 in the UK, 26 in Europe, 21 in Australia/New Zealand, and 23 in the US). Exposures: Receiving IMV. Main Outcomes and Measures: Primary analyses characterized types of initial IMV discontinuation events (extubation, SBT, or tracheostomy) and associations with clinical outcomes (including duration of ventilation, ICU and hospital mortality, and ICU and hospital length of stay). Secondary analyses examined the associations between SBT outcome and SBT timing and clinical outcomes. Results: Among 1868 patients (median [interquartile range] age, 61.8 [48.9-73.1] years; 1173 [62.8%] men) 424 (22.7%) underwent direct extubation, 930 (49.8%) had an initial SBT (761 [81.8%] successful), 150 (8.0%) underwent direct tracheostomy, and 364 (19.5%) died before a weaning attempt. Across regions, there was variation in the use of written directives to guide care, daily screening, SBT techniques, ventilator modes, and the roles played by clinicians involved in weaning. Compared with initial direct extubation, patients who had an initial SBT had higher ICU mortality (20 [4.7%] vs 96 [10.3%]; absolute difference, 5.6% [95% CI, 2.6%-8.6%]), longer duration of ventilation (median of 2.9 vs 4.1 days; absolute difference, 1.2 days [95% CI, 0.7-1.6]), and longer ICU stay (median of 6.7 vs 8.1 days; absolute difference, 1.4 days [95% CI, 0.8-2.4]). Patients whose initial SBT failed (vs passed) had higher ICU mortality (29 [17.2%] vs 67 [8.8%]; absolute difference, 8.4% [95% CI, 2.0%-14.7%]), longer duration of ventilation (median of 6.1 vs 3.5 days; absolute difference, 2.6 days [95% CI, 1.6-3.6]), and longer ICU stay (median of 10.6 vs 7.7 days; absolute difference, 2.8 days [95% CI, 1.1-5.2]). Compared with patients who underwent early initial SBTs, patients who underwent late initial SBTs (>2.3 days after intubation) had longer duration of ventilation (median of 2.1 vs 6.1 days; absolute difference, 4.0 days [95% CI, 3.7-4.5]), longer ICU stay (median of 5.9 vs 10.8 days; absolute difference, 4.9 days [95% CI, 4.0-6.3]), and longer hospital stay (median of 14.3 vs 22.8 days; absolute difference, 8.5 days [95% CI, 6.0-11.0]). Conclusions and Relevance: In this observational study of invasive mechanical ventilation discontinuation in 142 ICUs in Canada, India, the UK, Europe, Australia/New Zealand, and the US from 2013 to 2016, weaning practices varied internationally. Trial Registration: ClinicalTrials.gov Identifier: NCT03955874.

An Official American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline: Liberation from Mechanical Ventilation in Critically Ill Adults. Rehabilitation Protocols, Ventilator Liberation Protocols, and Cuff Leak Tests.

BACKGROUND: Interventions that lead to earlier liberation from mechanical ventilation can improve patient outcomes. This guideline, a collaborative effort between the American Thoracic Society and the American College of Chest Physicians, provides evidence-based recommendations to optimize liberation from mechanical ventilation in critically ill adults. METHODS: Two methodologists performed evidence syntheses to summarize available evidence relevant to key questions about liberation from mechanical ventilation. The methodologists appraised the certainty in the evidence (i.e., the quality of evidence) using the Grading of Recommendations, Assessment, Development, and Evaluation approach and summarized the results in evidence profiles. The guideline panel then formulated recommendations after considering the balance of desirable consequences (benefits) versus undesirable consequences (burdens, adverse effects, and costs), the certainty in the evidence, and the feasibility and acceptability of various interventions. Recommendations were rated as strong or conditional. RESULTS: The guideline panel made four conditional recommendations related to rehabilitation protocols, ventilator liberation protocols, and cuff leak tests. The recommendations were for acutely hospitalized adults mechanically ventilated for more than 24 hours to receive protocolized rehabilitation directed toward early mobilization, be managed with a ventilator liberation protocol, be assessed with a cuff leak test if they meet extubation criteria but are deemed high risk for postextubation stridor, and be administered systemic steroids for at least 4 hours before extubation if they fail the cuff leak test. CONCLUSIONS: The American Thoracic Society/American College of Chest Physicians recommendations are intended to support healthcare professionals in their decisions related to liberating critically ill adults from mechanical ventilation.

Official Executive Summary of an American Thoracic Society/American College of Chest Physicians Clinical Practice Guideline: Liberation from Mechanical Ventilation in Critically Ill Adults.

BACKGROUND: This clinical practice guideline addresses six questions related to liberation from mechanical ventilation in critically ill adults. It is the result of a collaborative effort between the American Thoracic Society and the American College of Chest Physicians. METHODS: A multidisciplinary panel posed six clinical questions in a Population, Intervention, Comparator, and Outcomes format. A comprehensive literature search and evidence synthesis was performed for each question, which included appraising the certainty in the evidence (i.e., the quality of evidence) using the Grading of Recommendations, Assessment, Development, and Evaluation approach. The Evidence-to-Decision framework was applied to each question, requiring the panel to evaluate and weigh the importance of the problem, the confidence in the evidence, the certainty about how much the public values the main outcomes, the magnitude and balance of desirable and undesirable outcomes, the resources and costs associated with the intervention, the impact on health disparities, and the acceptability and feasibility of the intervention. RESULTS: Evidence-based recommendations were formulated and graded initially by subcommittees and then modified after full-panel discussions. The recommendations were confirmed by confidential electronic voting; approval required that at least 80% of the panel members agree with the recommendation. CONCLUSIONS: The panel provides recommendations regarding liberation from mechanical ventilation. The details regarding the evidence and rationale for each recommendation are presented in the American Journal of Respiratory and Critical Care Medicine and Chest.

How we launched a developmental student-as-teacher (SAT) program for all medical students.

INTRODUCTION: Teaching is a necessary skill for medical trainees and physicians. We designed and launched a developmental Student-as-Teacher program for all students, beginning with the class of 2016. METHODS: A task force of faculty and students designed the program. The goal is to enable all students to acquire basic principles of teaching and learning at different stages in their four-year medical school career. Upon completion, students will achieve twenty-eight learning objectives grouped within four competency domains: (1) Adult and Practice-Based Learning; (2) Learning Environment; (3) Instructional Design and Performance; and, (4) Learner's Assessment and Evaluation. The program combines online learning modules and a field teaching experience. RESULTS: The entire class of 2016 (N = 200) completed the first online module. Students found the module effective, and 70% reported an increase in their level of knowledge. Although most students are expected to complete their field teaching experience in fourth year, twelve students completed their field experience in first year. Reported strengths of these experiences include reinforcement of their medical knowledge and improvement of their adult teaching skills. CONCLUSIONS: The program was successfully launched, and students are already experiencing the benefits of training in basic teaching skills in the first year of the program.

A Call to Action: Using Curriculum Mapping at Four Medical Schools in Massachusetts to Advance Serious Illness Communication Training in Undergraduate Medical Education.

Background: Practicing physicians require serious illness communication (SIC) skills to ensure high-quality, humanistic care for patients and families as they face life-changing medical decisions. However, a majority of U.S. medical schools do not require formal training in SIC and fail to provide students deliberate practice before graduation. The Massachusetts Medical Schools' Collaborative was created to ensure that students receive foundational SIC training in undergraduate medical education. This Collaborative developed a curriculum-mapping tool to assess SIC at four medical schools. Objective: We aimed to understand existing educational activities across four medical schools and identify opportunities to build longitudinal, developmentally based curricular threads in SIC. Design: From July 2019 to April 2021, faculty, staff, and medical students assessed current educational activities related to five core competencies in SIC, adapted for students from national competencies for palliative medicine fellows, using a curriculum mapping tool. Measurements: The group selected 23 keywords and collected metrics to describe the timing, instruction and assessment for each school's educational activities. Results: On average, there were only 40 hours of required curricula in SIC over four years. Over 80% of relevant SIC hours occurred as elective experiences, mostly during the postclerkship phase, with limited capacity in these elective experiences. Only one school had SIC educational activities during the clerkship phase when students are developing clinical competencies. Assessment methods focused on student participation, and no school-assessed clinical performance in the clerkship or postclerkship phase. Conclusions: Medical schools are failing to consistently train and ensure basic competency in effective, compassionate SIC. Curriculum mapping allows schools to evaluate their current state on a particular topic such as SIC, ensure proper assessment, and evaluate curricular changes over time. Through the deliberate inclusion of SIC competencies in longitudinal curriculum design, we can fill this training gap and create best practices in undergraduate medical education.

Curricular Reform in Serious Illness Communication and Palliative Care: Using Medical Students' Voices to Guide Change.

PURPOSE: To gather and leverage the voices of students to drive creation of required, integrated palliative care curricula within undergraduate medical education in Massachusetts, which is lacking in a majority of U.S. medical schools. METHOD: The study was conducted by the Massachusetts Medical Schools' Collaborative, a working group committed to ensuring all medical students in Massachusetts receive foundational training in serious illness communication (SIC) and palliative care. Eight focus groups (2 per participating medical school) were conducted during January-May 2021 and included a total of 50 students from Boston University Chobanian & Avedisian School of Medicine, Harvard Medical School, Tufts University School of Medicine, and the UMass Chan Medical School. Data collected from focus groups were discussed and coded. Themes were identified using the immersion/crystallization qualitative data analysis approach. RESULTS: Six key themes emerged. Students viewed SIC as essential to high-quality medical practice regardless of specialty, and believed training in SIC skills and palliative care should be required in medical school curricula. Students preferred to learn and practice these skills using frameworks, particularly in real-world situations. Students recognized the expertise of palliative care specialists and described them as a scarce, often misunderstood resource in health care. Students reported it was mostly "luck" if they were included in family meetings and observed good role models. Finally, students desired practice in debriefing after difficult and emotional situations. CONCLUSIONS: This study confirms long-standing themes on students' experiences with SIC and palliative care topics, including feeling inadequately prepared to care for seriously ill patients as future physicians. Our study collected students' perspectives as actionable data to develop recommendations for curricular change. Collaborative faculty also created recommendations based on the focus group data for immediate and ongoing SIC and palliative care curricular change in Massachusetts, which can apply to medical schools nationwide.

Characterizing the learning curve of the VBLaST-PT(©) (Virtual Basic Laparoscopic Skill Trainer).

BACKGROUND: Mastering laparoscopic surgical skills requires considerable time and effort. The Virtual Basic Laparoscopic Skill Trainer (VBLaST-PT(©)) is being developed as a computerized version of the peg transfer task of the Fundamentals of Laparoscopic Surgery (FLS) system using virtual reality technology. We assessed the learning curve of trainees on the VBLaST-PT(©) using the cumulative summation (CUSUM) method and compared them with those on the FLS to establish convergent validity for the VBLaST-PT(©). METHODS: Eighteen medical students from were assigned randomly to one of three groups: control, VBLaST-training, and FLS-training. The VBLaST and the FLS groups performed a total of 150 trials of the peg-transfer task over a 3-week period, 5 days a week. Their CUSUM scores were computed based on predefined performance criteria (junior, intermediate, and senior levels). RESULTS: Of the six subjects in the VBLaST-training group, five achieved at least the "junior" level, three achieved the "intermediate" level, and one achieved the "senior" level of performance criterion by the end of the 150 trials. In comparison, for the FLS group, three students achieved the "senior" criterion and all six students achieved the "intermediate" and "junior" criteria by the 150th trials. Both the VBLaST-PT(©) and the FLS systems showed significant skill improvement and retention, albeit with system specificity as measured by transfer of learning in the retention test: The VBLaST-trained group performed better on the VBLaST-PT(©) than on FLS (p = 0.003), whereas the FLS-trained group performed better on the FLS than on VBLaST-PT(©) (p = 0.002). CONCLUSIONS: We characterized the learning curve for a virtual peg transfer task on the VBLaST-PT(©) and compared it with the FLS using CUSUM analysis. Subjects in both training groups showed significant improvement in skill performance, but the transfer of training between systems was not significant.

Efficiency is not enough; you have to prove that you care: role modelling of compassionate care in an innovative resident-as-teacher initiative.

INTRODUCTION: The current emphasis on providing holistic competent and efficient healthcare has revealed a need to nurture providers' compassionate and relationship-centred care throughout the continuum of medical education. METHODS: Our resident-as-teacher programme trained 41 residents from core clerkships at six clinical sites in the United States of America (USA) to teach and practice compassionate care through role-modelling. The programme focused on resident's demonstrations or failures to demonstrate compassionate care with peers, students and healthcare providers, and engaged residents in disseminating their experience to their colleagues. A mixed-method evaluation assessed short-term outcomes at multiple levels through the collection of resident's: pre- and post-programme scores on empathy scale, performance on standardised patient (SP) exercise, and self-assessment of their performance on relationship-centred care skills; journal reflections; presentations delivered at their site and attendees' evaluation; evaluation of the programme. Quantitative data was analysed calculating descriptive statistics and paired sample t-tests, using SAS. Qualitative data was analysed performing open coding and code frequency counts to identify emergent themes. RESULTS: Residents had empathy scores within the average range, and high scores on SP assessments throughout the programme. The programme had a positive impact on resident's perceptions of their relationship-centred skills. Residents found the programme useful, and emphasised the importance of mindfulness, active presence and slowing down-and were concerned with addressing these needs in daily practice. Eighteen presentations were delivered across sites. Attendees found the presentations useful and necessary in their training. CONCLUSIONS: Residents successfully reflected on, embodied and disseminated the programme's core concepts on their rotations. This group required validation of their commitment to compassionate care, and sought strategies to embody their commitment while inspiring other providers, residents and students.

Differences in directives to limit treatment and discontinue mechanical ventilation between elderly and very elderly patients: a substudy of a multinational observational study.

PURPOSE: The aim of this study was to characterize differences in directives to limit treatments and discontinue invasive mechanical ventilation (IMV) in elderly (65-80 years) and very elderly (> 80 years) intensive care unit (ICU) patients. METHODS: We prospectively described new written orders to limit treatments, IMV discontinuation strategies [direct extubation, direct tracheostomy, spontaneous breathing trial (SBT), noninvasive ventilation (NIV) use], and associations between initial failed SBT and outcomes in 142 ICUs from 6 regions (Canada, India, United Kingdom, Europe, Australia/New Zealand, United States). RESULTS: We evaluated 788 (586 elderly; 202 very elderly) patients. Very elderly (vs. elderly) patients had similar withdrawal orders but significantly more withholding orders, especially cardiopulmonary resuscitation and dialysis, after ICU admission [67 (33.2%) vs. 128 (21.9%); p = 0.002]. Orders to withhold reintubation were written sooner in very elderly (vs. elderly) patients [4 (2-8) vs. 7 (4-13) days, p = 0.02]. Very elderly and elderly patients had similar rates of direct extubation [39 (19.3%) vs. 113 (19.3%)], direct tracheostomy [10 (5%) vs. 40 (6.8%)], initial SBT [105 (52%) vs. 302 (51.5%)] and initial successful SBT [84 (80%) vs. 245 (81.1%)]. Very elderly patients experienced similar ICU outcomes (mortality, length of stay, duration of ventilation) but higher hospital mortality [26 (12.9%) vs. 38 (6.5%)]. Direct tracheostomy and initial failed SBT were associated with worse outcomes. Regional differences existed in withholding orders at ICU admission and in withholding and withdrawal orders after ICU admission. CONCLUSIONS: Very elderly (vs. elderly) patients had more orders to withhold treatments after ICU admission and higher hospital mortality, but similar ICU outcomes and IMV discontinuation. Significant regional differences existed in withholding and withdrawal practices.

Characteristics and outcomes of ventilated patients according to time to liberation from mechanical ventilation.

RATIONALE: A new classification of patients based on the duration of liberation of mechanical ventilation has been proposed. OBJECTIVES: To analyze outcomes based on the new weaning classification in a cohort of mechanically ventilated patients. METHODS: Secondary analysis included 2,714 patients who were weaned and underwent scheduled extubation from a cohort of 4,968 adult patients mechanically ventilated for more than 12 hours. MEASUREMENTS AND MAIN RESULTS: Patients were classified according to a new weaning classification: 1,502 patients (55%) as simple weaning,1,058 patients (39%) as difficult weaning, and 154 (6%) as prolonged weaning.Variables associated with prolonged weaning(.7d)were: severity at admission (odds ratio [OR] per unit of Simplified Acute Physiology Score II, 1.01; 95% confidence interval [CI], 1.001­1.02), duration of mechanical ventilation before first attempt of weaning (OR per day, 1.10; 95% CI, 1.06­1.13), chronic pulmonary disease other than chronic obstructive pulmonary disease (OR,13.23; 95% CI, 3.44­51.05), pneumonia as the reason to start mechanical ventilation (OR, 1.82; 95% CI, 1.07­3.08), and level of positive end-expiratory pressure applied before weaning (OR per unit,1.09; 95% CI, 1.04­1.14). The prolonged weaning group had a nonsignificant trend toward a higher rate of reintubation (P » 0.08),tracheostomy (P » 0.15), and significantly longer length of stay and higher mortality in the intensive care unit (OR for death, 1.97;95%CI, 1.17­3.31). The adjusted probability of death remained constant until Day 7, at which point it increased to 12.1%.

Lessons learned from the introduction of personalized genotyping into a medical school curriculum.

PURPOSE: There is an expanding gap between the availability of direct-to-consumer whole genome testing and physician knowledge regarding interpretation of test results. Advances in the genomic literacy of health care providers will be necessary for genomics to exert its potential to affect clinical practice. However, implementation of a major shift in medical education to include genomics is not easily done. The purpose of this educational report is to describe efforts to incorporate knowledge of personalized medicine into a medical school curriculum. METHODS: In this report, we describe the experiences, both good and bad, of a multidisciplinary faculty group that examined ways to improve genomic education at Tufts University School of Medicine during a 16-month period. RESULTS: The results of the faculty's deliberation process resulted in the use of anonymous, rather than student genomes, to teach material on genomic medicine. CONCLUSION: Increased medical school education regarding genomic analysis and personalized medicine is a necessity, both to be able to translate the advances made by the Human Genome Project into improvements in human health and to begin to think of diseases as disruptions in specific pathways. Our experiences illustrate that adding this material to a medical school curriculum is a complex process that deserves careful thought and broad discussion within the academic community.

How often does patient-ventilator asynchrony occur and what are the consequences?

Mechanical ventilation can be life-saving for patients with acute respiratory failure. In between the 2 extremes of complete and no ventilatory support, both patient and machine contribute to ventilatory work. Ideally, ventilator gas delivery would perfectly match patient demand. This patient-ventilator interaction depends on how the ventilator responds to patient respiratory effort and, in turn, how the patient responds to the breath delivered by the ventilator. It is now evident that the interaction between patient and ventilator is frequently suboptimal and that patient-ventilator asynchrony is common. Its prevalence depends on numerous factors, including timing and duration of observation, technique used for detection, patient population, type of asynchrony, ventilation mode and settings (eg, trigger, flow, and cycle criteria), and confounding factors (eg, state of wakefulness, sedation). Patient-ventilator asynchrony is associated with adverse effects, including higher/wasted work of breathing, patient discomfort, increased need for sedation, confusion during the weaning process, prolonged mechanical ventilation, longer stay, and possibly higher mortality. Whether asynchrony is a marker of poor prognosis or causes these adverse outcomes remains to be determined.

Should a patient be extubated and placed on noninvasive ventilation after failing a spontaneous breathing trial?

Between 15% and 35% of mechanically ventilated patients fail an initial spontaneous breathing trial. For these patients, 40% of total time on mechanical ventilation is consumed by the weaning process (60% for patients with chronic obstructive pulmonary disease). Longer duration of mechanical ventilation is associated with higher risk of complications and probably with higher mortality. Noninvasive ventilation (NIV) has been used successfully in some forms of acute respiratory failure. Randomized controlled trials have indicated that, in selected patients with chronic obstructive pulmonary disease and acute-on-chronic respiratory failure, NIV can facilitate weaning, reduce the duration of invasive mechanical ventilation, decrease complications, and reduce mortality, compared to weaning on continued invasive ventilation. However, extubation failure resulting in re-intubation is associated with higher mortality, and this mortality risk increases with delay of re-intubation and may not be prevented by application of NIV. Patients extubated to NIV must have careful monitoring by skilled clinicians able to provide timely re-intubation if the patient shows signs of intolerance or worsening respiratory failure.

Should patients be able to follow commands prior to extubation?

The determination of optimal timing of liberation from mechanical ventilation requires a thorough assessment of multiple variables that can result in extubation failure. It is estimated that 5-20% of extubations fail. Traditional weaning parameters fail to predict extubation failure accurately, and attention has thus turned to improvements in extubation decision making through assessment of elements that may result in inability to protect the airway, such as excessive respiratory secretions, inadequate cough, and depressed mental status. Extubation is particularly controversial in patients with depressed mental status and inability to follow commands. When looking at univariate analyses, the reported studies are relatively evenly divided among those that did and did not find that inability to follow commands (ie, abnormal mental status) increases the risk of extubation failure. In addition, although extubation failure is a risk factor for poor overall outcome in heterogeneous populations, its impact on the patient failing with neurologic dysfunction has not been adequately determined. One limiting factor in all reported studies is how "inability to follow commands" is defined. The majority of studies use the Glasgow coma score, but this is difficult to determine in the intubated patient. Moreover, using the cutoff of Glasgow coma score >or= 8, favored by many authors, is questionable, as some patients with higher scores may be unable to follow commands. Currently it is agreed that many patients who are unable to follow commands, but have the ability to clear pulmonary secretions, can be safely extubated. A prospective, randomized trial using a more specific definition of "following commands" would certainly help remove some of the uncertainty in this patient population.

Can we identify patients at high risk for unplanned extubation? A large-scale multidisciplinary survey.

BACKGROUND: Unplanned extubation represents a threat to patient safety, and risk factors and prevention strategies for unplanned extubation have not been fully explored. OBJECTIVES: To define high-risk patients for unplanned extubation and determine clinicians' beliefs on perceived risks for unplanned extubation METHODS: With a Web-based survey instrument we surveyed critical care clinician members of the American Association for Respiratory Care, the American Association of Critical Care Nurses, and the Society of Critical Care Medicine. RESULTS: Surveys were completed by 1,976 clinicians, including 419 respiratory therapists, 870 critical care nurses, and 605 critical care physicians. The majority of respondents considered an outward migration of the endotracheal tube (by 3 cm, 2 cm if an air leak is present) to represent a risk for unplanned extubation. Respondents considered the following as high risk for unplanned extubation: absence of physical restraints (72% of respondents), a nurse/patient ratio of 1/3 (60%), trips out of the intensive care unit (59%), light sedation (43%), and bedside portable radiograph (29%). In addition, most respondents considered accidental removal of the nasogastric tube (71%) or tugging on the endotracheal tube (87%) by the patient to be risk factors for unplanned extubation. The rank order of the perceived risks was related to the respondents' primary discipline. CONCLUSIONS: We identified perceived risk factors and defined "near misses" for unplanned extubation. Our findings should inform strategies for prevention of unplanned extubation.

Using decentralized medical education to address the workforce needs of a rural state: a partnership between Maine Medical Center and Tufts University school of medicine.

CONTEXT: In February 2008, a new partnership between Maine Medical Center and Tufts University School of Medicine was formed to create a model medical school program. ISSUE: Major forces for change included: the increasing physician workforce needs of Maine, the need to increase access for medical education for Maine students, the opportunity for educational innovation, the societal imperative to increase the number of primary care physicians, and the desire for clinical and research collaborations. LESSONS LEARNED: The authors describe the process for exploring this partnership, and establishing a separate track and campus for 36 students per year. The key components of the 4 year curriculum, which includes clinical training based in Maine, are described, and 13 lessons learned to date are outlined. The authors hope these lessons provide guidance to other academic medical centers and medical schools wishing to address rural physician workforce challenges, through regional models of medical education, and similar partnerships.

Ineffective triggering predicts increased duration of mechanical ventilation.

OBJECTIVES: To determine whether high rates of ineffective triggering within the first 24 hrs of mechanical ventilation (MV) are associated with longer MV duration and shorter ventilator-free survival (VFS). DESIGN: Prospective cohort study. SETTING: Medical intensive care unit (ICU) at an academic medical center. PATIENTS: Sixty patients requiring invasive MV. INTERVENTIONS: None. MEASUREMENTS: Patients had pressure-time and flow-time waveforms recorded for 10 mins within the first 24 hrs of MV initiation. Ineffective triggering index (ITI) was calculated by dividing the number of ineffectively triggered breaths by the total number of breaths (triggered and ineffectively triggered). A priori, patients were classified into ITI >or=10% or ITI <10%. Patient demographics, MV reason, codiagnosis of chronic obstructive pulmonary disease (COPD), sedation levels, and ventilator parameters were recorded. MEASUREMENTS AND MAIN RESULTS: Sixteen of 60 patients had ITI >or=10%. The two groups had similar characteristics, including COPD frequency and ventilation parameters, except that patients with ITI >or=10% were more likely to have pressured triggered breaths (56% vs. 16%, p = .003) and had a higher intrinsic respiratory rate (22 breaths/min vs. 18, p = .03), but the set ventilator rate was the same in both groups (9 breaths/min vs. 9, p = .78). Multivariable analyses adjusting for pressure triggering also demonstrated that ITI >or=10% was an independent predictor of longer MV duration (10 days vs. 4, p = .0004) and shorter VFS (14 days vs. 21, p = .03). Patients with ITI >or=10% had a longer ICU length of stay (8 days vs. 4, p = .01) and hospital length of stay (21 days vs. 8, p = .03). Mortality was the same in the two groups, but patients with ITI >or=10% were less likely to be discharged home (44% vs. 73%, p = .04). CONCLUSIONS: Ineffective triggering is a common problem early in the course of MV and is associated with increased morbidity, including longer MV duration, shorter VFS, longer length of stay, and lower likelihood of home discharge.

Weaning from ventilatory support.

PURPOSE OF REVIEW: In intubated patients, mechanical ventilation offers essential ventilatory support, while the respiratory system recovers from acute respiratory failure. Yet, invasive mechanical ventilation is associated with risks and complications that prolong the duration of mechanical ventilation and increase the risk for death. Therefore, safely weaning the patient from the ventilator as soon as possible is paramount. Recent randomized trials have addressed a number of key areas of interest. RECENT FINDINGS: Determining readiness for spontaneous breathing, the first step in weaning, is best achieved using liberal oxygenation criteria; does not require routine use of weaning predictors; and can be conducted, in certain patient populations, using protocols driven by respiratory therapists or ICU nurses. Spontaneous breathing trials can be conducted on low levels of pressure support, continuous positive airway pressure, or T-piece. Weaning failure often results from an imbalance between respiratory load and capacity. There is increasing appreciation that cardiac dysfunction can limit weaning. Recent randomized trials suggest that noninvasive ventilation (in patients with chronic obstructive pulmonary disease) and computer-driven approaches show promise as weaning strategies. New techniques have been employed to identify patients at increased risk for extubation failure. Noninvasive ventilation, when used in high-risk patients, can decrease extubation failure. SUMMARY: Weaning from mechanical ventilation continues to be an area of considerable importance. Recent randomized controlled trials provide high-level evidence for the best approaches to weaning and extubation.

Routine use of weaning predictors: not so fast.

Weaning from mechanical ventilation remains a major challenge for critical care physicians. Because subjective criteria are inaccurate, objective measurements consisting of clinical criteria and physiologic tests (weaning predictors) have been used to facilitate decision-making. An integrated weaning index calculated as the product of static compliance and arterial oxygen saturation divided by the frequency-tidal volume ratio appears to be more accurate than other currently available predictors. Despite the accuracy of this new test, a beneficial effect on outcome is yet to be proven.

Noninvasive ventilation to shorten the duration of mechanical ventilation.

Noninvasive ventilation (NIV) successfully treats primary respiratory failure in chronic obstructive pulmonary disease (COPD), acute pulmonary edema, and, in some patients, hypoxemic respiratory failure. Increasingly clinicians have applied NIV in an effort to shorten the duration of mechanical ventilation by facilitating weaning and preventing or treating post-extubation respiratory failure. Randomized controlled trials (RCTs) indicate that NIV may be an effective weaning tool in a subset of patients with acute-on-chronic respiratory failure from COPD, and that applying immediate NIV to extubated patients at high risk for extubation failure improves outcome by decreasing the need for reintubation. In contrast, there is mixed evidence about the effectiveness of NIV to treat established post-extubation respiratory failure. NIV appeared to be ineffective in heterogeneous patient populations in some randomized trials that enrolled relatively few patients with COPD, and a case-control study found that NIV decreased the need for reintubation in this group. Therefore, as with primary therapy, NIV should be considered for patients with COPD and post-extubation respiratory distress.