Search

Objective: Significant variations exist in the use of respiratory muscle ultrasound in intensive care with no society-level consensus on the optimal methodology. This systematic review aims to evaluate, synthesize, and compare the clinimetric properties of different image acquisition and analysis methodologies., Data Sources: Systematic search of five databases up to November 24, 2021., Study Selection: Studies were included if they enrolled at least 50 adult ICU patients, reported respiratory muscle (diaphragm or intercostal) ultrasound measuring either echotexture, muscle thickness, thickening fraction, or excursion, and evaluated at least one clinimetric property. Two independent reviewers assessed titles, abstracts, and full text against eligibility., Data Extraction: Study demographics, ultrasound methodologies, and clinimetric data., Data Synthesis: Sixty studies, including 5,025 patients, were included with 39 studies contributing to meta-analyses. Most commonly measured was diaphragm thickness (DT) or diaphragm thickening fraction (DTF) using a linear transducer in B-mode, or diaphragm excursion (DE) using a curvilinear transducer in M-mode. There are significant variations in imaging methodology and acquisition across all studies. Inter- and intrarater measurement reliabilities were generally excellent, with the highest reliability reported for DT (ICC, 0.98; 95% CI, 0.94-0.99). Pooled data demonstrated acceptable to excellent accuracy for DT, DTF, and DE to predicting weaning outcome after 48 to 72 hours postextubation (DTF AUC, 0.79; 95% CI, 0.73-0.85). DT imaging was responsive to change over time. Only three eligible studies were available for intercostal muscles. Intercostal thickening fraction was shown to have excellent accuracy of predicting weaning outcome after 48-hour postextubation (AUC, 0.84; 95% CI, 0.78-0.91)., Conclusions: Diaphragm muscle ultrasound is reliable, valid, and responsive in ICU patients, but significant variation exists in the imaging acquisition and analysis methodologies. Future work should focus on developing standardized protocols for ultrasound imaging and consider further research into the role of intercostal muscle imaging., Competing Interests: Dr. Parry is currently a recipient of a Val and Al Rosenstrauss Fellowship. Dr. Sarwal’s institution has received compensation for research support for conducting multicenter clinical trials from Bard, Biogen, Novartis, and CVR Global. Her institute has received compensation from LungPacer and NIH/NIA R01 AG066910-01 (Brinkley/Shaltout) for her role as a consultant for ultrasound image analysis in clinical research trial. She has received honorarium, free meeting registration, or reimbursement of travel expenses for role as speaker from Society of Critical Care Medicine, Neurocritical Society, Indian Society of Critical Care Medicine, Indian Academy of Neurology, American Institute of Ultrasound in Medicine, Intensive Care Society, American College of Chest Physicians, American Thoracic Society, and American Association of Physical Therapists. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2023 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Objectives: To identify whether factors associated with withholding extubation in the ICU also predict the risk of extubation failure., Design: Retrospective cohort study., Setting: Eight medical-surgical ICUs in Toronto., Patients: Adult patients receiving invasive mechanical ventilation, with a first successful spontaneous breathing trial within 28 days of initial ICU admission., Interventions: None., Measurements and Main Results: The primary end point had three mutually exclusive levels, including: 1) withholding extubation after a successful spontaneous breathing trial, 2) extubation failure within 48 hours, and 3) successful extubation. Among 9,910 patients, 38% of patients were not extubated within 24 hours of their first successful spontaneous breathing trial. A total of 12.9% of patients who were promptly extubated failed within the next 48 hours. Several discrepancies were evident in the association of factors with risk of withholding extubation and extubation failure. Specifically, both age and female sex were associated with withholding extubation (odds ratio, 1.07; 95% CI, 1.03-1.11; and odds ratio, 1.13; 95% CI, 1.02-1.26, respectively) but not a higher risk of failed extubation (odds ratio, 0.99; 95% CI, 0.93-1.05; and odds ratio, 0.93; 95% CI, 0.77-1.11, respectively). Conversely, both acute cardiovascular conditions and intubation for hypoxemic respiratory failure were associated with a higher risk of failed extubation (odds ratio, 1.32; 95% CI, 1.06-1.66; and odds ratio, 1.46; 95% CI, 1.16-1.82, respectively) but not a higher odds of a withheld extubation attempt (odds ratio, 0.79; 95% CI, 0.68-0.91; and odds ratio, 1.07; 95% CI, 0.93-1.23, respectively)., Conclusions: Several factors showed discordance between the decision to withhold extubation and the risk of extubation failure. This discordance may lead to longer duration of mechanical ventilation or higher reintubation rates. Improving the decision-making behind extubation may help to reduce both exposure to invasive mechanical ventilation and extubation failure., Competing Interests: Dr. Ferreyro is supported by a Vanier Canada Graduate Scholarship from the Canadian Institutes of Health Research. Dr. Angriman is supported by a Vanier Canada Graduate Scholarship from the Canadian Institutes of Health Research. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2021 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

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., Competing Interests: Dr. de Souza disclosed that this study was partially supported by Universidade Estácio de Sá by a research productivity program and disclosed off-label product use of the digital vacuometer MVD 300 (Globalmed, Porto Alegre, Brazil) and the device POWERbreathe K-5 and the software (BreatheLink; Power Breathe International, Warwickshire, United Kingdom). Dr. Alvim disclosed government work. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2020 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Objectives: Inspiratory holds with measures of airway pressure to estimate driving pressure (elastic work) are often limited to patients without respiratory effort. We sought to evaluate if measures of airway pressure during inspiratory holds could be used for patients with spontaneous respiratory effort during mechanical ventilation to estimate the degree of spontaneous effort and elastic work., Design: We compared the direction and degree of change in airway pressure during inspiratory holds versus esophageal pressure through secondary analysis of physiologic data., Setting: ICUs at Children's Hospital Los Angeles., Patients: Children with pediatric acute respiratory distress syndrome with evidence of spontaneous respiration while on pressure control or pressure support ventilation., Interventions: Inspiratory hold maneuvers., Measurements and Main Results: From airway pressure, we defined "plateau - peak pressure" as Pmusc, index, which was divided into three categories for analysis (< -1 ["negative"], between -1 and 1 ["neutral"], and > 1 cm H2O ["positive"]). A total of 30 children (age 36.8 mo [16.1-70.3 mo]) from 65 study days, comprising 118 inspiratory holds were included. Pmusc, index was "negative" in 29 cases, was "neutral" in 17 cases, and was "positive" in 72 cases. As Pmusc, index went from negative to neutral to positive, there was larger negative deflection in esophageal pressure -5.0 (-8.2 to 1.9), -5.9 (-7.6 to 4.3), and -10.7 (-18.1 to 7.9) cm H2O (p < 0.0001), respectively. There was a correlation between max negative esophageal pressure and Pmusc, index (r = -0.52), and when Pmusc, index was greater than or equal to 7 cm H2O, the max negative esophageal pressure was greater than 10 cm H2O. There was a stronger correlation between Pmusc, index and markers of elastic work from esophageal pressure (r = 0.84)., Conclusions: The magnitude of plateau minus peak pressure during an inspiratory hold is correlated with the degree of inspiratory effort, particularly for those with high elastic work. It may be useful to identify patients with excessively high effort or high driving pressure., Competing Interests: Dr. Bellani has received lecturing fees from Draeger Medical, Getinge, Hamilton, and GE Healthcare. Dr. Kyogoku’s institution received funding from National Heart Lung and Blood Institute and United States National Institutes of Health (NIH) (R01HL124666, to principal investigator: Dr. Khemani). Dr. Newth received funding from Philips Research North America and Hamilton Medical AG. Dr. Khemani’s institution received funding from the NIH and Securysin Medical; he received funding from Orange Med and Hamilton Medical; and he received support for article research from the NIH. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2020 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Objectives: There is limited evidence on the impact of protocolized ventilator weaning in pediatric acute respiratory distress syndrome, despite utilization in clinical trials and clinical care. We aimed to determine whether protocolized ventilator weaning shortens mechanical ventilation duration and PICU length of stay in pediatric acute respiratory distress syndrome survivors., Design: Secondary analysis of a prospective pediatric acute respiratory distress syndrome (Berlin definition) cohort from July 2011 to June 2019 analyzed using interrupted time series analysis pre- and postimplementations of a ventilator-weaning pathway. We compared duration of invasive ventilation and PICU length of stay in survivors before and after implementation of a ventilator-weaning pathway. We excluded PICU nonsurvivors and subjects with greater than 100 ventilator days., Setting: Large academic tertiary-care PICU., Patients: Children with acute respiratory distress syndrome who survived to PICU discharge with less than or equal to 100 days of invasive mechanical ventilation., Interventions: Implementation of a ventilator-weaning pathway on May 2016., Measurements and Main Results: Of 723 children with acute respiratory distress syndrome, 132 subjects died and six subjects with ventilation greater than 100 days were excluded. Of the remaining 585 subjects, 375 subjects had acute respiratory distress syndrome prior to pathway intervention and 210 after. Patients in the preintervention epoch were younger, more likely to have infectious acute respiratory distress syndrome, and had increased use of alternative ventilator modes. Pathway adoption was rapid and sustained. Controlling for temporality, pathway implementation was associated with a decrease of a median 3.6 ventilator days (95% CI, -5.4 to -1.7; p < 0.001). There was no change in the reintubation rates. Results were robust to multiple sensitivity analyses adjusting for confounders., Conclusions: Ventilator-weaning pathway implementation shortened invasive ventilation duration in pediatric acute respiratory distress syndrome survivors with no change in reintubation. The effect size of this intervention was comparable with those targeted in acute respiratory distress syndrome trials., Competing Interests: Dr. Yehya’s institution received funding from the National institutes of Health (NIH), and he received support for article research from the NIH. The remaining authors have disclosed that they do not have any potential conflicts of interest., (Copyright © 2020 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.)

Objectives: Physical therapy is standard care for mechanically ventilated patients, but there is no evidence, using nonvolitional, objective measurements, that physical therapy increases muscle strength in this population. The present study tested the hypothesis that 2 weeks of standard, conventional physical therapy provided at a ventilator weaning facility would increase quadriceps strength in mechanically ventilated patients., Design: Prospective observational study., Setting: Ventilator weaning unit., Patients: Patients who were transferred from an acute care hospital because of failure to wean from mechanical ventilation and who were receiving physical therapy as prescribed by facility staff., Interventions: None., Measurements and Main Results: We employed a novel, nonvolitional objective technique, quadriceps twitch force generation in response to femoral nerve magnetic stimulation, to assess leg strength before and after 2 weeks of conventional physical therapy. The duration and specific exercises provided to patients were also recorded. In a subset of patients, we measured muscle activation intensity using wireless electromyogram recordings. Indices of respiratory function (maximum inspiratory pressure generation and the rapid shallow breathing index) were also assessed. Patients' responses to 2 weeks of physical therapy were poor; on average, quadriceps twitch fell by -1.02 ± 0.71 Newtons. Neither physical therapy duration nor specific forms of exercise were identified to positively impact quadriceps twitch. Electromyogram recordings indicated that during training, muscle activation was poor. Consequently, therapists spent substantial time performing exercises that elicited little muscle activation. Physical therapy did not improve respiratory function., Conclusions: Standard physical therapy delivered in a ventilator weaning facility failed to improve quadriceps leg strength in a majority of mechanically ventilated patients. The fact that mechanically ventilated patients fail to achieve high levels of muscle activation during physical therapy provides a potential explanation as to why physical therapy may often be ineffective. We speculate that use of novel methods which increase muscle activation during exercise may improve responses of mechanically ventilated patients to physical therapy.

Objectives: To evaluate the ability of central venous-to-arterial carbon dioxide pressure difference, central venous oxygen saturation, and the combination of these two parameters to detect extubation failure in critically ill patients., Design: Multicentric, prospective, observational study., Setting: Three ICUs., Patients: All patients who received mechanical ventilation for more than 48 hours and tolerated spontaneous breathing trials with a T-piece for 60 minutes., Interventions: Extubation after successful spontaneous breathing trials. Extubation failure was defined as the need for mechanical ventilation within 48 hours., Measurements and Main Results: The oxygen delivery index, oxygen consumption index, central venous oxygen saturation, central venous-to-arterial carbon dioxide pressure difference, and oxygen extraction were measured immediately before spontaneous breathing trials and at 60 minutes after spontaneous breathing trials initiation. Seventy-five patients were enrolled, and extubation failure was noted in 18 (24%) patients. Oxygen consumption index increased significantly during spontaneous breathing trials in the failure group. Oxygen delivery index increased in both success and failure groups. Oxygen extraction increased in the failure group (p = 0.005) and decreased in the success group (p = 0.001). Central venous oxygen saturation decreased in the failure group and increased in the success group (p = 0.014). ΔPCO2 value increased in the extubation failure group and decreased in the success group (p = 0.002). Changes in ΔPCO2 (Δ - ΔPCO2) and central venous oxygen saturation (ΔScvO2) during spontaneous breathing trials were independently associated with extubation failure (odds ratio, 1.02; 95% CI, 1.01-1.05; p = 0.006, and odds ratio, 0.84; 95% CI, 0.70-0.95; p = 0.02, respectively). Δ - ΔPCO2 and central venous oxygen saturation could predict extubation failure with areas under the curve of 0.865 and 0.856, respectively; however, their combined areas under the curve was better at 0.940., Conclusions: We found that Δ - ΔPCO2 and central venous oxygen saturation, during spontaneous breathing trials, were independent predictors of weaning outcomes. Combination analysis of both parameters enhanced their diagnostic performance and provided excellent predictability in extubation failure detection in critically ill patients.

Objectives: We sought to evaluate the impact of transitions of care among staff intensivists on the compliance with evidence-based processes of care., Design: Cohort study using data from the Toronto Intensive Care Observational Registry., Setting: Seven academic ICUs in Toronto, Ontario., Patients: Critically ill mechanically ventilated adult patients., Interventions: We explored the effects of the weekly transition of care among staff intensivists on compliance with three evidence-based processes of care (spontaneous breathing trials, lung-protective ventilation, and neuromuscular blocking agents). Two practices that are less guided by evidence (early discontinuation of antibiotics and extubation attempts) served as positive controls. We conducted the analysis using generalized estimating equations to account for clustering at the patient level., Measurements and Main Results: The cohort consisted of 10,570 patients admitted between June 2014 and August 2018. Compliance varied for each practice (63.6%, 42.5%, and 21.1% for lung-protective ventilation, spontaneous breathing trials, and neuromuscular blockade, respectively). There was no effect of transitions of care on compliance with spontaneous breathing trials (odds ratio, 1.00; 95% CI, 0.95-1.07), lung-protective ventilation (odds ratio, 1.07, 95% CI, 0.90-1.26), or neuromuscular blockade use (odds ratio, 0.95; 95% CI, 0.75-1.20). However, early antibiotic discontinuation was more likely (odds ratio, 1.23; 95% CI, 1.06-1.42) and extubation attempts were less frequent (odds ratio, 0.77; 95% CI, 0.65-0.93) after a transition of care., Conclusions: We observed no significant impact of transitions of care between individual staff physicians on evidence-based processes of care for mechanically ventilated adult patients. However, transitions were associated with a lower likelihood of extubation and higher odds of earlier discontinuation of antibiotics.

Objective: Identifying children ready for extubation is desirable to minimize morbidity and mortality associated with prolonged mechanical ventilation and extubation failure. We determined the accuracy of an extubation readiness test (Randomized Evaluation of Sedation Titration for Respiratory Failure extubation readiness test) in predicting successful extubation in children with acute respiratory failure from lower respiratory tract disease., Design: Secondary analysis of data from the Randomized Evaluation of Sedation Titration for Respiratory Failure clinical trial, a pediatric multicenter cluster randomized trial of sedation., Setting: Seventeen PICUs in the intervention arm., Patients: Children 2 weeks to 17 years receiving invasive mechanical ventilation for lower respiratory tract disease., Intervention: Extubation readiness test in which spontaneously breathing children with oxygenation index less than or equal to 6 were placed on FIO2 of 0.50, positive end-expiratory pressure of 5 cm H2O, and pressure support., Measurements and Main Results: Of 1,042 children, 444 (43%) passed their first extubation readiness test. Of these, 295 (66%) were extubated within 10 hours of starting the extubation readiness test, including 272 who were successfully extubated, for a positive predictive value of 92%. Among 861 children who were extubated for the first time within 10 hours of performing an extubation readiness test, 788 passed their extubation readiness test and 736 were successfully extubated for a positive predictive value of 93%. The median time of day for extubation with an extubation readiness test was 12:15 hours compared with 14:54 hours for extubation without an extubation readiness test within 10 hours (p < 0.001)., Conclusions: In children with acute respiratory failure from lower respiratory tract disease, an extubation readiness test, as described, should be considered at least daily if the oxygenation index is less than or equal to 6. If the child passes the extubation readiness test, there is a high likelihood of successful extubation.

Objective: Controversy exists regarding perceived benefits of early tracheostomy to facilitate weaning among mechanically ventilated patients, potentially leading to significant practice-pattern variation with implications for outcomes and resource utilization. We sought to determine practice-pattern variation and outcomes associated with tracheostomy timing in the United States., Design: In a retrospective cohort study, we identified mechanically ventilated patients with the most common causes of respiratory failure leading to tracheostomy: pneumonia/sepsis and trauma. "Early tracheostomy" was performed within the first week of mechanical ventilation. We determined between-hospital variation in early tracheostomy utilization and the association of early tracheostomy with patient outcomes using hierarchical regression., Setting: 2012 National Inpatient Sample., Patients: A total of 6,075 pneumonia/sepsis patients and 12,030 trauma patients with tracheostomy., Interventions: None., Measurements and Main Results: Trauma patients were twice as likely as pneumonia/sepsis patients to receive early tracheostomy (44.5% vs 21.7%; p < 0.001). Admission to hospitals with higher early tracheostomy-to-total-tracheostomy ratios was associated with increased risk for tracheostomy among mechanically ventilated trauma patients (adjusted odds ratio = 1.04; 95% CI, 1.01-1.07) but not pneumonia/sepsis (adjusted odds ratio =1.00; 95% CI, 0.98-1.02). We observed greater between-hospital variation in early tracheostomy rates among trauma patients (21.9-81.9%) compared with pneumonia/sepsis (14.9-38.3%; p < 0.0001). We found no evidence of improved hospital mortality. Pneumonia/sepsis patients with early tracheostomy had fewer feeding tube procedures and higher odds of discharge home., Conclusion: Early tracheostomy is potentially overused among mechanically ventilated trauma patients, with nearly half of tracheostomies performed within the first week of mechanical ventilation and large unexplained hospital variation, without clear benefits. Future studies are needed to characterize potentially differential benefits for early tracheostomy between disease subgroups and to investigate factors driving hospital variation in tracheostomy timing.

Objectives: Despite protocols incorporating spontaneous breathing trials, 31% of ICU patients experience difficult or prolonged weaning from mechanical ventilation. Nonfatiguing modes such as pressure support ventilation are recommended. Proportional assist ventilation provides assistance in proportion to patient effort, which may optimize weaning. However, it is not known how proportional assist ventilation performs relative to pressure support ventilation over a prolonged period in the complex ICU setting. The purpose of this study was to compare the physiologic and clinical performance (failure rate), safety, and feasibility of protocols using daily spontaneous breathing trial plus pressure support ventilation versus proportional assist ventilation until ventilation discontinuation., Design: Single-center, unblinded pilot randomized controlled trial., Setting: Medical-surgical ICU of a tertiary-care hospital., Patients: Adult patients intubated greater than 36 hours were randomized if they met eligibility criteria for partial ventilatory support, tolerated pressure support ventilation greater than or equal to 30 minutes, and either failed or did not meet criteria for a spontaneous breathing trial., Interventions: Patients were randomized to the pressure support ventilation or proportional assist ventilation protocol (PAV+, Puritan Bennett 840; Covidien, Boulder, CO). Both protocols used progressive decreases in level of assistance as tolerated, coupled with daily assessment for spontaneous breathing trials., Measurements and Main Results: Of 54 patients randomized, outcome data are available for 50 patients; 27 were randomized to receive proportional assist ventilation and 23 to receive pressure support ventilation. There were no adverse events linked to the study interventions, and protocol violations were infrequent. Recruitment was slower than projected (1.3 patients per month). The median (interquartile range) time from randomization to successful extubation was 3.9 days (2.8-8.4 d) on proportional assist ventilation versus 4.9 days (2.9-26.3 d) on pressure support ventilation (p = 0.39). Time to live ICU discharge was 7.3 days (5.2-11.4 d) on proportional assist ventilation versus 12.4 days (7.5-30.8 d) on pressure support ventilation (p = 0.03)., Conclusion: This pilot study demonstrates the utility, safety, and feasibility of the weaning protocols and provides important information to guide the design of a future randomized controlled trial comparing weaning from mechanical ventilation on pressure support ventilation versus proportional assist ventilation.

Objective: The debilitating and persistent effects of ICU-acquired delirium and weakness warrant testing of prevention strategies. The purpose of this study was to evaluate the effectiveness and safety of implementing the Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility bundle into everyday practice., Design: Eighteen-month, prospective, cohort, before-after study conducted between November 2010 and May 2012., Setting: Five adult ICUs, one step-down unit, and one oncology/hematology special care unit located in a 624-bed tertiary medical center., Patients: Two hundred ninety-six patients (146 prebundle and 150 postbundle implementation), who are 19 years old or older, managed by the institutions' medical or surgical critical care service., Interventions: Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility bundle., Measurements and Main Results: For mechanically ventilated patients (n = 187), we examined the association between bundle implementation and ventilator-free days. For all patients, we used regression models to quantify the relationship between Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility bundle implementation and the prevalence/duration of delirium and coma, early mobilization, mortality, time to discharge, and change in residence. Safety outcomes and bundle adherence were monitored. Patients in the postimplementation period spent three more days breathing without mechanical assistance than did those in the preimplementation period (median [interquartile range], 24 [7-26] vs 21 [0-25]; p = 0.04). After adjusting for age, sex, severity of illness, comorbidity, and mechanical ventilation status, patients managed with the Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility bundle experienced a near halving of the odds of delirium (odds ratio, 0.55; 95% CI, 0.33-0.93; p = 0.03) and increased odds of mobilizing out of bed at least once during an ICU stay (odds ratio, 2.11; 95% CI, 1.29-3.45; p = 0.003). No significant differences were noted in self-extubation or reintubation rates., Conclusions: Critically ill patients managed with the Awakening and Breathing Coordination, Delirium monitoring/management, and Early exercise/mobility bundle spent three more days breathing without assistance, experienced less delirium, and were more likely to be mobilized during their ICU stay than patients treated with usual care.

Objectives: During proportional assist ventilation with load-adjustable gain factors, peak respiratory muscle pressure can be estimated from the peak airway pressure and the percentage of assistance (gain). Adjusting the gain can, therefore, target a given level of respiratory effort. This study assessed the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors with the goal of targeting a predefined range of respiratory effort., Design: Prospective, multicenter, clinical observational study., Settings: Intensive care departments at five university hospitals., Patients: Patients were included after meeting simple criteria for assisted mechanical ventilation., Interventions: Patients were ventilated in proportional assist ventilation with load-adjustable gain factors. The peak respiratory muscle pressure, estimated in cm H2O as (peak airway pressure-positive end-expiratory pressure)×[(100-gain)/gain], was calculated from a grid at the bedside. The gain adjustment algorithm was defined to target a peak respiratory muscle pressure between 5 and 10 cm H2O. Additional recommendations were available in case of hypoventilation or hyperventilation., Results: Fifty-three patients were enrolled. Median time spent under proportional assist ventilation with load-adjustable gain factors was 3 days (interquartile range, 1-5). Gain was adjusted 1.0 (0.7-1.8) times per day, according to the peak respiratory muscle pressure target range in 91% of cases and because of hypoventilation or hyperventilation in 9%. Thirty-four patients were ventilated with proportional assist ventilation with load-adjustable gain factors until extubation, which was successful in 32. Eighteen patients required volume assist-controlled reventilation because of clinical worsening and need for continuous sedation. One patient was intolerant to proportional assist ventilation with load-adjustable gain factors., Conclusions: This first study assessing the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors in an attempt to target a predefined range of effort showed that adjusting the level of assistance to maintain a predefined boundary of respiratory muscle pressure is feasible, simple, and often sufficient to ventilate patients until extubation.

Objective: Recognition of the cardiac origin of weaning failure is a crucial issue for successful discontinuation of mechanical ventilation. Bedside lung ultrasound and echocardiography have shown a potential in predicting weaning failure. Objective of this report was to describe the case of a patient repeatedly failing to wean from mechanical ventilation, where the combined use of lung ultrasound and echocardiography during a spontaneous breathing trial uncovered an unexpected cause of the failure., Design: Case report., Setting: General ICU of a university teaching hospital., Patients: Single case, abdominal surgery postoperative patient, not predicted to experience a difficult weaning., Interventions: Cardiovascular therapy adjustments consistent with lung ultrasound and echocardiography findings acquired during spontaneous breathing trials., Measurements and Main Results: All patient's standard hemodynamic and respiratory parameters, datasets from comprehensive lung ultrasound and echocardiographic examinations, and pertinent data from biochemistry exams, were collected during two spontaneous breathing trials. Data from beginning and end of each of the two ultrasound monitored weaning trials, and from the end of the successful weaning trial following therapy and the previously failed one, were analyzed and qualitatively compared. Lung ultrasound performed at the end of the failed spontaneous breathing trial showed a pattern consistent with increased extravascular lung water (diffuse, bilateral, symmetrical, homogeneous sonographic interstitial syndrome). Concurrent echocardiography diagnosed left ventricular diastolic failure. Ultrasound findings at the end of the successful weaning trial showed normalization of the lung pattern and improvement of the echocardiographic one. The patient eventually returned to spontaneous respiration and was discharged from the ICU., Conclusions: The use of bedside lung ultrasound and echocardiography disclosed left ventricular diastolic dysfunction as unexpected cardiogenic cause of weaning failure and lead to subsequent correct patient management.

Objectives: Spontaneous awakening trials (SATs) improve outcomes in mechanically ventilated patients, but implementation remains erratic. We examined variation in reported practice, prevalence of attitudes and fears regarding spontaneous awakening trials, and organizational practices associated with routine implementation of spontaneous awakening trials in an ICU quality improvement collaborative., Design: Written survey., Setting: Michigan Health and Hospital Association's Keystone ICU, a quality improvement collaborative of 73 hospitals., Subjects: Attendees of the yearly Keystone ICU meeting, January 2011, including nurses, physicians, hospital administrators, and other healthcare professionals., Intervention: Respondents were asked about institutional characteristics, spontaneous awakening trial practice, attitudes and barriers regarding spontaneous awakening trials, and organizational cultural characteristics that might influence SAT practice. The association of organizational cultural characteristics and attitudes with reported spontaneous awakening trial use was evaluated using logistic regression., Measurements and Main Results: Three hundred nineteen participants attended the meeting. The survey response rate was 83.4%. Respondents reported wide variation in approach to spontaneous awakening trial performance and patient selection. 48.6% of respondents reported regular spontaneous awakening trial use, defined as greater than 75% of mechanically ventilated patients undergoing spontaneous awakening trials each day. In bivariable analysis, addressing sedation goals routinely in rounds and having spontaneous awakening trials as part of unit culture were positively associated with regular spontaneous awakening trial use, whereas the perception that spontaneous awakening trials increased short-term adverse effects, staff fears of spontaneous awakening trials, and the perception that spontaneous awakening trials are hard work were negatively associated with regular spontaneous awakening trial use. In multivariable analysis, only addressing sedation in rounds (odds ratio, 2.85 [95% CI, 1.55-5.23]), incorporation of spontaneous awakening trials into unit culture (odds ratio, 3.36 [95% CI, 1.75-6.43]), and the perception that spontaneous awakening trials are hard work (odds ratio, 0.53 [95% CI, 0.30-0.96]) remained statistically significantly associated with regular spontaneous awakening trial use. Respondents in managerial positions were less likely to perceive spontaneous awakening trials as hard work (odds ratio, 0.44 [95% CI, 0.22-0.85])., Conclusions: Even in a motivated statewide quality improvement collaborative, spontaneous awakening trial practice varies widely and concerns persist regarding spontaneous awakening trials. Cultural practices may counteract the effect of concerns regarding spontaneous awakening trials and are associated with increased performance of this beneficial intervention. Patient selection should be a focus for continuing medical education. Differences in perception of work between management and staff may also be a focus for improved communication.

Objectives: To compare the respective impact of pressure support ventilation and naturally adjusted ventilatory assist, with and without a noninvasive mechanical ventilation algorithm, on patient-ventilator interaction., Design: Prospective 2-month study., Setting: Adult critical care unit in a tertiary university hospital., Patients: Seventeen patients receiving a prophylactic postextubation noninvasive mechanical ventilation., Interventions: Patients were randomly mechanically ventilated for 10 mins with: pressure support ventilation without a noninvasive mechanical ventilation algorithm (PSV-NIV-), pressure support ventilation with a noninvasive mechanical ventilation algorithm (PSV-NIV+), neurally adjusted ventilatory assist without a noninvasive mechanical ventilation algorithm (NAVA-NIV-), and neurally adjusted ventilatory assist with a noninvasive mechanical ventilation algorithm (NAVA-NIV+)., Measurements and Main Results: Breathing pattern descriptors, diaphragm electrical activity, leak volume, inspiratory trigger delay, inspiratory time in excess, and the five main asynchronies were quantified. Asynchrony index and asynchrony index influenced by leaks were computed. Peak inspiratory pressure and diaphragm electrical activity were similar for each of the four experimental conditions. For both pressure support ventilation and neurally adjusted ventilatory assist, the noninvasive mechanical ventilation algorithm significantly reduced the level of leakage (p < .01). Inspiratory trigger delay was not affected by the noninvasive mechanical ventilation algorithm but was shorter in neurally adjusted ventilatory assist than in pressure support ventilation (p < .01). Inspiratory time in excess was shorter in neurally adjusted ventilatory assist and PSV-NIV+ than in PSV-NIV- (p < .05). Asynchrony index was not affected by the noninvasive mechanical ventilation algorithm but was significantly lower in neurally adjusted ventilatory assist than in pressure support ventilation (p < .05). Asynchrony index influenced by leaks was insignificant with neurally adjusted ventilatory assist and significantly lower than in pressure support ventilation (p < .05). There was more double triggering with neurally adjusted ventilatory assist., Conclusions: Both neurally adjusted ventilatory assist and a noninvasive mechanical ventilation algorithm improve patient-ventilator synchrony in different manners. NAVA-NIV+ offers the best compromise between a good patient-ventilator synchrony and a low level of leaks. Clinical studies are required to assess the potential clinical benefit of neurally adjusted ventilatory assist in patients receiving noninvasive mechanical ventilation., Trial Registration: Clinicaltrials.gov Identifier NCT01280760.

Objectives: To assess whether the combination of daily evaluation and use of a spontaneous breathing test could shorten the duration of mechanical ventilation as compared with weaning based on our standard of care. Secondary outcome measures included extubation failure rate and the need for noninvasive ventilation., Design: A prospective, randomized controlled trial., Setting: Two pediatric intensive care units at university hospitals in Brazil., Patients: The trial involved children between 28 days and 15 yrs of age who were receiving mechanical ventilation for at least 24 hrs., Interventions: Patients were randomly assigned to one of two weaning protocols. In the test group, the children underwent a daily evaluation to check readiness for weaning with a spontaneous breathing test with 10 cm H2O pressure support and a positive end-expiratory pressure of 5 cm H2O for 2 hrs. The spontaneous breathing test was repeated the next day for children who failed it. In the control group, weaning was performed according to standard care procedures., Measurements and Main Results: A total of 294 eligible children were randomized, with 155 to the test group and 139 to the control group. The time to extubation was shorter in the test group, where the median mechanical ventilation duration was 3.5 days (95% confidence interval, 3.0 to 4.0) as compared to 4.7 days (95% confidence interval, 4.1 to 5.3) in the control group (p = .0127). This significant reduction in the mechanical ventilation duration for the intervention group was not associated with increased rates of extubation failure or noninvasive ventilation. It represents a 30% reduction in the risk of remaining on mechanical ventilation (hazard ratio: 0.70)., Conclusions: A daily evaluation to check readiness for weaning combined with a spontaneous breathing test reduced the mechanical ventilation duration for children on mechanical ventilation for >24 hrs, without increasing the extubation failure rate or the need for noninvasive ventilation.

Objective: To investigate the influence of different ventilatory supports on the predictive performance of breathing pattern variability for extubation outcomes in intensive care unit patients., Design and Setting: A prospective measurement of retrospectively analyzed breathing pattern variability in a medical center., Patients: Sixty-eight consecutive and ready-for-weaning patients were divided into success (n=45) and failure (n=23) groups based on their extubation outcomes., Measurements: Breath-to-breath analyses of peak inspiratory flow, total breath duration, tidal volume, and rapid shallow breathing index were performed for three 30-min periods while patients randomly received T-piece, 100% inspiratory automatic tube compensation with 5 cm H2O positive end-expiratory pressure, and 5 cm H2O pressure support ventilation with 5 cm H2O positive end-expiratory pressure trials. Coefficient of variations and data dispersion (standard descriptor values SD1 and SD2 of the Poincaré plot) were analyzed to serve as breathing pattern variability indices., Main Results: Under all three trials, breathing pattern variability in extubation failure patients was smaller than in extubation success patients. Compared to the T-piece trial, 100% inspiratory automatic tube compensation with 5 cm H2O positive end-expiratory pressure and 5 cm H2O pressure support ventilation with 5 cm H2O positive end-expiratory pressure decreased the ability of certain breathing pattern variability indices to discriminate extubation success from extubation failure. The areas under the receiver operating characteristic curve of these breathing pattern variability indices were: T-piece (0.73-0.87)>100% inspiratory automatic tube compensation with 5 cm H2O positive end-expiratory pressure (0.60-0.79)>5 cm H2O pressure support ventilation with 5 cm H2O positive end-expiratory pressure (0.53-0.76). Analysis of the classification and regression tree indicated that during the T-piece trial, a SD1 of peak inspiratory flow>3.36 L/min defined a group including all extubation success patients. Conversely, the combination of a SD1 of peak inspiratory flow ≤3.36 L/min and a coefficient of variations of rapid shallow breathing index ≤0.23 defined a group of all extubation failure patients. The decision strategies using SD1 of peak inspiratory flow and coefficient of variations of rapid shallow breathing index measured during 100% inspiratory automatic tube compensation with 5 cm H2O positive end-expiratory pressure and 5 cm H2O pressure support ventilation with 5 cm H2O positive end-expiratory pressure trials achieved a less clear separation of extubation failure from extubation success., Conclusions: Since 100% inspiratory automatic tube compensation with 5 cm H2O positive end-expiratory pressure and 5 cm H2O pressure support ventilation with 5 cm H2O positive end-expiratory pressure reduce the predictive performance of breathing pattern variability, breathing pattern variability measurement during the T-piece trial is the best choice for predicting extubation outcome in intensive care unit patients patients.

Objective: To evaluate the predictive value of central venous saturation to detect extubation failure in difficult-to-wean patients., Design: Cohort, multicentric, clinical study., Setting: Three medical-surgical intensive care units., Patients: All difficult-to-wean patients (defined as failure to tolerate the first 2-hr T-tube trial), mechanically ventilated for >48 hrs, were extubated after undergoing a two-step weaning protocol (measurements of predictors followed by a T-tube trial). Extubation failure was defined as the need of reintubation within 48 hrs., Interventions: The weaning protocol evaluated hemodynamic and ventilation parameters, and arterial and venous gases during mechanical ventilation (immediately before T-tube trial), and at the 30th min of spontaneous breathing trial., Measurements and Main Results: Seventy-three patients were enrolled in the study over a 6-mo period. Reintubation rate was 42.5%. Analysis by logistic regression revealed that central venous saturation was the only variable able to discriminate outcome of extubation. Reduction of central venous saturation by >4.5% was an independent predictor of reintubation, with odds ratio of 49.4 (95% confidence interval 12.1-201.5), a sensitivity of 88%, and a specificity of 95%. Reduction of central venous saturation during spontaneous breathing trial was associated with extubation failure and could reflect the increase of respiratory muscles oxygen consumption., Conclusions: Central venous saturation was an early and independent predictor of extubation failure and may be a valuable accurate parameter to be included in weaning protocols of difficult-to-wean patients.

Physical deconditioning and prolonged motor weakness accompanying critical illness have profound and lasting consequences for both patients and their informal caregivers. The etiology is multifactorial and the effects may be mitigated by an early mobility process. Early mobility is facilitated by change in intensive care unit culture that requires clinicians to: 1) reorganize and manage current practices that have the potential to interfere with mobility; 2) create a strategy to improve the level of teamwork; and 3) link effective practice intervention and teamwork with short- and long-term patient-centered outcomes.

The general issue of weaning can be viewed as composed of three different groups of patients. First, simple or easy weaning, represents 60% to 70% of patients whose first trial of spontaneous breathing is successful. The main objective of the weaning process is to detect weaning readiness as early as possible, which is best achieved using a systematic approach. The percentage of patients in this group in a given intensive care unit represents the pretest probability of weaning. A second group is made of patients who experience failure of the first spontaneous breathing trial and in whom up to 7 days from the first trial may be required to achieve weaning. This group represents 20% to 25% of patients who undergo weaning from mechanical ventilation. Muscle weakness contributes to the prolongation of weaning in many of these patients. The last group is made of patients who are characterized by a prolonged or very difficult weaning process (about 5% to 15% of patients undergoing weaning). Muscle weakness is likely to be a major contributing factor. Early use of spontaneous breathing, well-controlled use of sedation, and early mobilization may help in reducing muscle weakness and hasten the weaning process. The postextubation period may be particularly at risk in these patients. More research is needed to guide clinicians regarding the best ventilatory management.

Objective: To review current knowledge about the impact of prolonged mechanical ventilation on diaphragmatic function and biology., Measurements: Systematic literature review., Conclusions: Prolonged mechanical ventilation can promote diaphragmatic atrophy and contractile dysfunction. As few as 18 hrs of mechanical ventilation results in diaphragmatic atrophy in both laboratory animals and humans. Prolonged mechanical ventilation is also associated with diaphragmatic contractile dysfunction. Studies using animal models revealed that mechanical ventilation-induced diaphragmatic atrophy is due to increased diaphragmatic protein breakdown and decreased protein synthesis. Recent investigations have identified calpain, caspase-3, and the ubiquitin-proteasome system as key proteases that contribute to mechanical ventilation-induced diaphragmatic proteolysis. The scientific challenge for the future is to delineate the mechanical ventilation-induced signaling pathways that activate these proteases and depress protein synthesis in the diaphragm. Future investigations that define the signaling mechanisms responsible for mechanical ventilation-induced diaphragmatic weakness will provide the knowledge required for the development of new medicines that can maintain diaphragmatic mass and function during prolonged mechanical ventilation.

Objective: Weaning-induced pulmonary edema is a cause of weaning failure in high-risk patients. The diagnosis may require pulmonary artery catheterization to demonstrate increased pulmonary artery occlusion pressure (PAOP) during weaning. Transthoracic echocardiography can estimate left ventricular filling pressures using early (E) and late (A) peak diastolic velocities measured with Doppler transmitral flow, and tissue Doppler imaging of mitral annulus velocities including early (Ea) peak diastolic velocity. We tested the hypothesis that E/A and E/Ea could be used to detect weaning-induced PAOP elevation defined by a PAOP > or =18 mm Hg during a spontaneous breathing trial (SBT)., Measurements and Main Results: We included 39 patients who previously failed two consecutive SBTs. A third SBT was performed over a maximum 1-hour period using a T-piece. The PAOP, E/A, and E/Ea were measured before and during this SBT. Receiver operating characteristic curves were constructed to determine the optimal sensitivity and specificity values of E/A and E/Ea obtained at the end of the SBT for predicting a weaning-induced PAOP elevation. Weaning-induced PAOP elevation occurred in 17 patients. A value of E/A >0.95 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 88% and a specificity of 68%. A value of E/Ea >8.5 at the end of the SBT predicted weaning-induced PAOP elevation with a sensitivity of 94% and a specificity of 73%. The combination of E/A >0.95 and E/Ea >8.5 predicted a weaning-induced PAOP elevation with a sensitivity of 82% and a specificity of 91%., Conclusion: At the end of an SBT, the combination of E/A >0.95 and E/Ea >8.5 measured with transthoracic echocardiography allowed an accurate noninvasive detection of weaning-induced PAOP elevation.

Objective: To assess whether a systematic approach to weaning and extubation (intervention) is superior to the sole physician's judgment (control) in preventing reintubation secondary to extubation failure in patients with neurologic disorders., Design: Randomized controlled trial., Setting: Intensive care unit of a large teaching hospital., Patients: Three hundred eighteen intubated patients who had been receiving mechanical ventilation for at least 12 hrs and were able to trigger the ventilator., Interventions: Patients were randomized to the intervention (n = 165) or control group (n = 153)., Measurements: Rate of reintubation after extubation failure occurring within 48 hrs (primary end point). Duration of mechanical ventilation, length of intensive care unit stay, mortality, rate of tracheotomy (secondary end points). The perception of the research protocol by the intensive care unit staff was also assessed., Main Results: The rate of reintubation was lower in the intervention (5%) than in the control (12.5%) group (p = 0.047). There was no difference in any of the other outcome variables (secondary end points). Simplified Acute Physiologic Score II (adjusted odds ratio 1.042 per unit; 95% confidence interval 1.006-1.080; p = 0.022) and inclusion in the control group (adjusted odds ratio 2.393; 95% confidence interval 1.000-5.726; p = 0.05) were the only two independent predictive factors for the risk of extubation failure. The protocol was felt by the staff to determine an improvement in patients' clinical outcome, but to increase intensive care unit workload; nurses and physiotherapists considered its impact on their professional role more positively than physicians., Conclusions: In patients with neurologic diseases, a systematic approach to weaning and extubation reduces the rate of reintubation secondary to extubation failure without affecting the duration of mechanical ventilation, and is overall positively perceived by intensive care unit professionals.

Objective: To evaluate the effect of the implementation of a nursing-driven protocol of sedation on duration of intubation., Design: Before-and-after prospective study., Setting: 18-bed medical-surgical intensive care unit., Patients: Patients receiving mechanical ventilation longer than 48 hrs who were ready to wean., Interventions: During the observational period, sedatives and analgesics were adjusted according to physicians' orders. During the intervention period, sedatives and analgesics were adjusted by nurses according to an algorithm-based sedation guideline, including a sedation scale., Measurements and Main Results: A total of 356 patients were included in the study (176 patients in the observational period and 189 patients in the intervention period). There were no significant differences in the duration of intubation between the two periods (median, 7 [interquartile range, 5-13] days vs. 7 [interquartile range, 5-9] days). In a Kaplan-Meier analysis, the probability of successful extubation was higher during the intervention period than during the observational period (log-rank = 0.02). During the intervention period, patients were more awake without a significant increment in the nurse workload; however, there was no significant decrease in the total doses of sedatives and analgesics administered., Conclusions: The implementation of a nursing-driven protocol of sedation may improve the probability of successful extubation in a heterogeneous population of mechanically ventilated patients.

Objective: Despite the use of spontaneous breathing trial (SBT), predicting weaning success remains a major clinical challenge. Because cardiovascular dysfunction could be a major underlying mechanism of weaning failure, we evaluated the role of the levels of B-type natriuretic peptide (BNP), a marker for cardiovascular function, in patients who passed a 2-hr SBT., Design, Setting, and Patients: Fifty-two patients recovering from acute respiratory failure were enrolled as the testing group to determine the predictive value of BNP. The predictive value of BNP was validated in a second independent cohort of 49 patients. Then, we combined both groups of patients to conduct the final analysis., Measurements and Results: In the testing group of 52 patients, 41 passed SBT and were extubated. Of these patients, 33 patients (80%) were extubated successfully (extubation success) while eight patients (20%) were reintubated within 48 hrs (extubation failure). There were no differences in the baseline BNP levels, but the extubation failure group had significantly greater increases in BNP at the end of SBT than the extubation success groups (32.7%, 25-75 percentile = 25.7%-50.8% vs. 0.69%, -8.8%-10.72%, p < .001). The area under the receiver operating characteristic curves for the BNP change was 0.93 and an increase of BNP <20% during SBT had the best combination of sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy for predicting extubation success (91%, 88%, 97%, 70%, and 91%). This threshold value of BNP change was then validated in an independent cohort. Combining BNP with SBT as extubation criteria increased the extubation success rate to 95% from 78% using SBT alone (p = .035)., Conclusion: Measuring the percentage change in the BNP level during a SBT may help improve the predictive value of SBT on weaning outcome.

Objectives: Acute kidney injury (AKI) worsens outcome in various scenarios. We sought to investigate whether the occurrence of AKI has any effect on weaning from mechanical ventilation., Design and Setting: Observational, retrospective study in a 23-bed medical/surgical intensive care unit (ICU) in a cancer hospital from January to December 2003., Patients: The inclusion criterion was invasive mechanical ventilation for > or =48 hrs. AKI was defined as at least one measurement of serum creatinine of > or =1.5 mg/dL during the ICU stay. Patients were then separated into AKI and non-AKI patients (control group). The criterion for weaning was the combination of positive end-expiratory pressure of < or =8 cm H2O, pressure support of < or =10 cm H2O, and Fio2 of < or =0.4, with spontaneous breathing. The primary end point was duration of weaning and the secondary end points were rate of weaning failure, total length of mechanical ventilation, length of stay in the ICU, and ICU mortality., Results: A total of 140 patients were studied: 93 with AKI and 47 controls. The groups were similar in regard to age, sex, and type of tumor. Diagnosis of acute lung injury/acute respiratory distress syndrome as cause of respiratory failure and Simplified Acute Physiology Score II at admission did not differ between groups. During ICU stay, AKI patients had markers of more severe disease: increased occurrence of severe sepsis or septic shock, higher number of antibiotics, and longer use of vasoactive drugs. The median (interquartile range) duration of mechanical ventilation (10 [6-17] vs. 7 [2-12] days, p = .017) and duration of weaning from mechanical ventilation (41 [16-97] vs. 21 [7-33.5] hrs, p = .018) were longer in AKI patients compared with control patients. Cox regression analysis demonstrated that a > or =85% increase in baseline serum creatinine (hazard rate, 2.30; 95% confidence interval, 1.30-4.08), oliguria (hazard rate, 2.51; 95% confidence interval, 1.24-5.08), and the number of antibiotics (hazard rate, 2.64; 95% confidence interval, 1.51-4.63) predicted longer duration of weaning. The length of ICU stay and ICU mortality rate were significantly greater in the AKI patients. After adjusting for Simplified Acute Physiology Score II, oliguria (odds ratio, 30.8; 95% confidence interval, 7.7-123.0) remained as a strong risk factor for mortality., Conclusion: This study shows that renal dysfunction has serious consequences in the duration of mechanical ventilation, weaning from mechanical ventilation, and mortality in critically ill cancer patients.

Objective: Weaning predictors are often incorporated in protocols to predict weaning outcome for patients on mechanical ventilation. The predictors are used as a decision point in protocols to determine whether a patient may advance to a spontaneous breathing trial. The impact of including predictors in a weaning protocol has not been previously studied. We designed a study to determine the effect of including a weaning predictor (frequency-tidal volume ratio, or f/Vt) in a weaning protocol., Design: Randomized, blinded controlled trial., Setting: Academic teaching hospitals., Patients: Three hundred and four patients admitted to intensive care units at three academic teaching hospitals., Interventions: Patients were screened daily for measures of oxygenation, cough and secretions, adequate mental status, and hemodynamic stability. Patients were randomized to two groups; in one group the f/Vt was measured but not used in the decision to wean (n = 151), but in the other group, f/Vt was measured and used, using a threshold of 105 breaths/min/L (n = 153). Patients passing the screen received a 2-hr spontaneous breathing trial. Patients passing the spontaneous breathing trial were eligible for an extubation attempt., Measurements and Main Results: Groups were similar with regard to gender, age, and Acute Physiology and Chronic Health Evaluation II score. The median duration for weaning time was significantly shorter in the group where the weaning predictor was not used (2.0 vs. 3.0 days, p = .04). There was no difference with regard to the extubation failure, in-hospital mortality rate, tracheostomy, or unplanned extubation., Conclusions: Including a weaning predictor (f/Vt) in a protocol prolonged weaning time. In addition, the predictor did not confer survival benefit or reduce the incidence of extubation failure or tracheostomy. The results of this study indicate that f/Vt should not be used routinely in weaning decision making.

Objective: We hypothesized that the additional use of automatic tube compensation (ATC) during a spontaneous breathing trial with continuous positive airway pressure (CPAP), by minimizing respiratory work, would result in more patients undergoing successful extubation., Design: Prospective, randomized, controlled study., Setting: A ten-bed, general intensive care department at a tertiary-care hospital., Patients: Adult patients (n=99) who had undergone mechanical ventilation for >24 hrs and met defined criteria for a weaning trial., Interventions: Patients were randomized to undergo a 1-hr spontaneous breathing trial with either ATC with CPAP (ATC group, n=51) or CPAP alone (CPAP group, n=48). ATC was provided by commercially available mechanical ventilators. Patients tolerating the spontaneous breathing trial underwent immediate extubation. The primary outcome measure was successful extubation, defined as the ability to maintain spontaneous breathing for 48 hrs after discontinuation of mechanical ventilation and extubation., Measurements and Main Results: There were no significant differences in demographic, respiratory, or hemodynamic characteristics between the two groups at the start of the spontaneous breathing trial. There was a trend for more patients in the ATC group to tolerate the breathing trial and undergo extubation (96% vs. 85%; p=.08). The rate of reintubation was 14% in the ATC group and 24% in the CPAP group (p=.28). Significantly more patients in the ATC group thus met the criteria for successful extubation (82% vs. 65%; p=0.04)., Conclusion: This is the largest single-center study to date assessing the use of commercially available ATC and suggests that this might be a useful mode for performing a spontaneous breathing trial preceding extubation in a general intensive care population.

Objective: Compared with standard medical therapy (SMT), noninvasive ventilation (NIV) does not reduce the need for reintubation in unselected patients who develop respiratory failure after extubation. The goal of this study was to assess whether early application of NIV, immediately after extubation, is effective in preventing postextubation respiratory failure in an at-risk population., Design: Multiple-center, randomized controlled study., Setting: Multiple hospitals., Patients: Ninety-seven consecutive patients with similar baseline characteristics, requiring >48 hrs of mechanical ventilation and considered at risk of developing postextubation respiratory failure (i.e., patients who had hypercapnia, congestive heart failure, ineffective cough and excessive tracheobronchial secretions, more than one failure of a weaning trial, more than one comorbid condition, and upper airway obstruction)., Interventions: After a successful weaning trial, the patients were randomized to receive NIV for > or = 8 hrs a day in the first 48 hrs or SMT. Primary outcome was the need for reintubation according to standardized criteria. Secondary outcomes were intensive care unit and hospital mortality, as well as time spent in the intensive care unit and in hospital., Measurements and Main Results: Compared with the SMT group, the NIV group had a lower rate of reintubation (four of 48 vs. 12 of 49; p = .027). The need for reintubation was associated with a higher risk of mortality (p < .01). The use of NIV resulted in a reduction of risk of intensive care unit mortality (-10%, p < .01), mediated by the reduction for the need of reintubation., Conclusions: NIV was more effective than SMT in preventing postextubation respiratory failure in a population considered at risk of developing this complication.