Reverse triggering ? a novel or previously missed phenomenon?

BACKGROUND

Reverse triggering (RT) was described in 2013 as a form of patient-ventilator asynchrony, where patient's respiratory effort follows mechanical insufflation. Diagnosis requires esophageal pressure (Pes) or diaphragmatic electrical activity (EAdi), but RT can also be diagnosed using standard ventilator waveforms.

HYPOTHESIS

We wondered (1) how frequently RT would be present but undetected in the figures from literature, especially before 2013; (2) whether it would be more prevalent in the era of small tidal volumes after 2000.

METHODS

We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, from 1950 to 2017, with key words related to asynchrony to identify papers with figures including ventilator waveforms expected to display RT if present. Experts labelled waveforms. 'Definite' RT was identified when Pes or EAdi were in the tracing, and 'possible' RT when only flow and pressure waveforms were present. Expert assessment was compared to the author's descriptions of waveforms.

RESULTS

We found 65 appropriate papers published from 1977 to now, containing 181 ventilator waveforms. 21 cases of 'possible' RT and 25 cases of 'definite' RT were identified by the experts. 18.8% of waveforms prior to 2013 had evidence of RT. Most cases were published after 2000 (1 before vs. 45 after, p = 0.03). 54% of RT cases were attributed to different phenomena. A few cases of identified RT were already described prior to 2013 using different terminology (earliest in 1997). While RT cases attributed to different phenomena decreased after 2013, 60% of 'possible' RT remained missed.

CONCLUSION

RT has been present in the literature as early as 1997, but most cases were found after the introduction of low tidal volume ventilation in 2000. Following 2013, the number of undetected cases decreased, but RT are still commonly missed. Reverse Triggering, A Missed Phenomenon in the Literature. Critical Care Canada Forum 2019 Abstracts. Can J Anesth/J Can Anesth 67 (Suppl 1), 1-162 (2020). https://doi-org.myaccess.library.utoronto.ca/ https://doi.org/10.1007/s12630-019-01552-z .

Sex and gender-based analysis and diversity metric reporting in acute care trials published in high-impact journals: a systematic review

OBJECTIVE

To characterise sex and gender-based analysis (SGBA) and diversity metric reporting, representation of female/women participants in acute care trials and temporal changes in reporting before and after publication of the 2016 Sex and Gender Equity in Research guideline.

DESIGN

Systematic review.

DATA SOURCES

We searched MEDLINE for trials published in five leading medical journals in 2014, 2018 and 2020.

STUDY SELECTION

Trials that enrolled acutely ill adults, compared two or more interventions and reported at least one clinical outcome.

DATA ABSTRACTION AND SYNTHESIS

4 reviewers screened citations and 22 reviewers abstracted data, in duplicate. We compared reporting differences between intensive care unit (ICU) and cardiology trials.

RESULTS

We included 88 trials (75 (85.2%) ICU and 13 (14.8%) cardiology) (n=111 428; 38 140 (34.2%) females/women). Of 23 (26.1%) trials that reported an SGBA, most used a forest plot (22 (95.7%)), were prespecified (21 (91.3%)) and reported a sex-by-intervention interaction with a significance test (19 (82.6%)). Discordant sex and gender terminology were found between headings and subheadings within baseline characteristics tables (17/32 (53.1%)) and between baseline characteristics tables and SGBA (4/23 (17.4%)). Only 25 acute care trials (28.4%) reported race or ethnicity. Participants were predominantly white (78.8%) and male/men (65.8%). No trial reported gendered-social factors. SGBA reporting and female/women representation did not improve temporally. Compared with ICU trials, cardiology trials reported significantly more SGBA (15/75 (20%) vs 8/13 (61.5%) p=0.005).

CONCLUSIONS

Acute care trials in leading medical journals infrequently included SGBA, female/women and non-white trial participants, reported race or ethnicity and never reported gender-related factors. Substantial opportunity exists to improve SGBA and diversity metric reporting and recruitment of female/women participants in acute care trials.

PROSPERO REGISTRATION NUMBER

CRD42022282565.

Spontaneous Breathing Trial Techniques for Extubating Adults and Children Who Are Critically Ill: A Systematic Review and Meta-Analysis

Importance

Considerable controversy exists regarding the best spontaneous breathing trial (SBT) technique to use.

Objective

To summarize trials comparing alternative SBTs.

Data Sources

Several databases (MEDLINE [from inception to February 2023], the Cochrane Central Register of Controlled Trials [in February 2023], and Embase [from inception to February 2023] and 5 conference proceedings (from January 1990 to April 2023) were searched in this systematic review and meta-analysis.

Study Selection

Randomized trials directly comparing SBT techniques in critically ill adults or children and reporting at least 1 clinical outcome were selected.

Data Extraction and Synthesis

Paired reviewers independently screened citations, abstracted data, and assessed quality for the systematic review and meta-analysis using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA guidelines). Data were pooled using random-effects models.

Main Outcomes and Measures

Primary outcomes included SBT success, extubation success, and reintubation.

Results

The systematic review and meta-analysis identified 40 trials that included 6716 patients. Low-quality evidence (14 trials [n = 4459]) suggested that patients were not more likely to pass a pressure support (PS) compared with a T-piece SBT (risk ratio [RR], 1.04; 95% CI, 0.97-1.11; P = .31; I2 = 73%), unless 1 outlier trial accounting for all heterogeneity was excluded (RR, 1.09; 95% CI, 1.06-1.12; P < .001; I2 = 0% [13 trials; n = 3939]; moderate-quality evidence), but were significantly more likely to be successfully extubated (RR, 1.07; 95% CI, 1.04-1.10; P < .001; I2 = 0%; 16 trials [n = 4462]; moderate-quality evidence). Limited data (5 trials [n = 502]) revealed that patients who underwent automatic tube compensation/continuous positive airway pressure compared with PS SBTs had a significantly higher successful extubation rate (RR, 1.10; 95% CI, 1.00-1.21; P = .04; I2 = 0% [low-quality evidence]). Compared with T-piece SBTs, high-flow oxygen SBTs (3 trials [n = 386]) had significantly higher successful extubation (RR, 1.06; 95% CI, 1.00-1.11; P = .04; I2 = 0%) and lower reintubation (RR, 0.37; 95% CI, 0.21-0.65; P = <.001; I2 = 0% [both low-quality evidence]) rates. Credible subgroup effects were not found.

Conclusions and Relevance

In this systematic review and meta-analysis, the findings suggest that patients undergoing PS compared with T-piece SBTs were more likely to be extubated successfully and more likely to pass an SBT, after exclusion of an outlier trial. Pressure support SBTs were not associated with increased risk of reintubation. Future trials should compare SBT techniques that maximize differences in inspiratory support.

Inter-limb kinetic asymmetries during sit-to-stand performance persist following unilateral total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Kinetic asymmetries during sit-to-stand have been consistently observed early after total knee arthroplasty; however, the longer-term outcomes are less clear. The purpose of this systematic review and meta-analysis was to analyze the results of studies examining inter-limb kinetic symmetry during sit-to-stand performance among individuals who were at least one-year post unilateral total knee arthroplasty.

METHODS

PubMed, SPORTDiscus, CINAHL, and Health Source databases were searched. Studies were included if they were published in a peer-reviewed journal, included subjects who had undergone unilateral total knee arthroplasty at least one-year prior, and examined vertical ground reaction forces and/or knee extension moments for the involved and uninvolved limbs during sit-to-stand performance. Data were transformed into a limb symmetry index, which expressed the ratio of the peak forces/moments for the involved limb, relative to the uninvolved limb (1.0 reflects perfect symmetry). These ratios were meta-analyzed using the ratio of means method.

FINDINGS

Seven studies were deemed eligible for inclusion. Ground reaction force data was pooled from seven studies and knee extension moment data was pooled from two studies. For the peak vertical ground reaction forces, the pooled limb symmetry index was 0.96 (CI95% = [0.93, 0.99]). For the peak knee extension moments, the pooled limb symmetry index was 0.91 (CI95% = [0.84, 0.98]). In both cases this reflects greater limb/knee loading for the uninvolved limb, relative to the involved limb.

INTERPRETATION

Asymmetries in limb/knee loading persist beyond the one-year post-operative period following total knee arthroplasty, potentially contributing to degenerative changes for the uninvolved limb.

Mortality As a Measure of Treatment Effect in Clinical Trials Recruiting Critically Ill Patients

OBJECTIVES

All-cause mortality is a common measure of treatment effect in ICU-based randomized clinical trials (RCTs). We sought to understand the performance characteristics of a mortality endpoint by evaluating its temporal course, responsiveness to differential treatment effects, and impact when used as an outcome measure in trials of acute illness.

DATA SOURCES

We searched OVID Medline for RCTs published from 1990 to 2018.

STUDY SELECTION

We reviewed RCTs that had randomized greater than or equal to 100 patients, were published in one of five high-impact general medical or eight critical care journals, and reported mortality at two or more distinct time points. We excluded trials recruiting pediatric or neonatal patients and cluster RCTs.

DATA EXTRACTION

Mortality by randomization group was recorded from the article or estimated from survival curves. Trial impact was assessed by inclusion of results in clinical practice guidelines.

DATA SYNTHESIS

From 2,592 potentially eligible trials, we included 343 RCTs (228,784 adult patients). While one third of all deaths by 180 days had occurred by day 7, the risk difference between study arms continued to increase until day 60 (p = 0.01) and possibly day 90 (p = 0.07) and remained stable thereafter. The number of deaths at ICU discharge approximated those at 28-30 days (95% [interquartile range [IQR], 86-106%]), and deaths at hospital discharge approximated those at 60 days (99% [IQR, 94-104%]). Only 13 of 43 interventions (30.2%) showing a mortality benefit have been adopted into widespread clinical practice.

CONCLUSIONS

Our findings provide a conceptual framework for choosing a time horizon and interpreting mortality outcome in trials of acute illness. Differential mortality effects persist for 60 to 90 days following recruitment. Location-based measures approximate time-based measures for trials conducted outside the United States. The documentation of a mortality reduction has had a modest impact on practice.

Reducing unnecessary diagnostic phlebotomy in intensive care: a prospective quality improvement intervention

BACKGROUND

Critically ill patients receive frequent routine and recurring blood tests, some of which are unnecessary.

AIM

To reduce unnecessary routine phlebotomy in a 30-bed tertiary medical-surgical intensive care unit (ICU) in Toronto, Ontario.

METHODS

This prospective quality improvement study included a 7-month preintervention baseline, 5-month intervention and 11-month postintervention period. Change strategies included education, ICU rounds checklists, electronic order set modifications, an electronic test add-on tool and audit and feedback. The primary outcome was mean volume of blood collected per patient-day. Secondary outcomes included the number blood tubes used and red cell transfusions. Balancing measures included the timing and types of blood tests, ICU length of stay and mortality. Outcomes were evaluated using process control charts and segmented regression.

RESULTS

Patient demographics did not differ between time periods; total number of patients: 2096, median age: 61 years, 60% male. Mean phlebotomy volume±SD decreased from 41.1±4.0 to 34.1±4.7 mL/patient-day. Special cause variation was met at 13 weeks. Segmental regression demonstrated an immediate postintervention decrease of 6.6 mL/patient-day (95% CI 1.8 to 11.4 p=0.009), which was sustained. Blood tube consumption decreased by 1.4 tubes/patient-day (95% CI 0.4 to 2.4, p=0.005) amounting to 13 276 tubes (95% CI 4602 to 22 127 tubes) saved over 11 months. Red blood cell transfusions decreased from 10.5±5.2 to 8.3±4.4 transfusions/100 patient-days (incident rate ratio 0.56, 95% CI 0.35 to 0.88, p=0.01). There was no impact on length of stay (2 days, IQR 1-5) and mortality (18.1%±2.0%).

CONCLUSION

Iterative improvement interventions targeting clinician test ordering behaviour can reduce ICU phlebotomy and may impact red cell transfusions. Frequent stakeholder consultation, incorporating stewardship into daily workflow, and audit and feedback are effective strategies.

The Usefulness of the Rapid Shallow Breathing Index in Predicting Successful Extubation: A Systematic Review and Meta-analysis

BACKGROUND

Clinicians use several measures to ascertain whether individual patients will tolerate liberation from mechanical ventilation, including the rapid shallow breathing index (RSBI).

RESEARCH QUESTION

Given varied use of different thresholds, patient populations, and measurement characteristics, how well does RSBI predict successful extubation?

STUDY DESIGN AND METHODS

We searched six databases from inception through September 2019 and selected studies reporting the accuracy of RSBI in the prediction of successful extubation. We extracted study data and assessed quality independently and in duplicate.

RESULTS

We included 48 studies involving RSBI measurements of 10,946 patients. Pooled sensitivity for RSBI of < 105 in predicting extubation success was moderate (0.83 [95% CI, 0.78-0.87], moderate certainty), whereas specificity was poor (0.58 [95% CI, 0.49-0.66], moderate certainty) with diagnostic ORs (DORs) of 5.91 (95% CI, 4.09-8.52). RSBI thresholds of < 80 or 80 to 105 yielded similar sensitivity, specificity, and DOR. These findings were consistent across multiple subgroup analyses reflecting different patient characteristics and operational differences in RSBI measurement.

INTERPRETATION

As a stand-alone test, the RSBI has moderate sensitivity and poor specificity for predicting extubation success. Future research should evaluate its role as a permissive criterion to undergo a spontaneous breathing trial (SBT) for patients who are at intermediate pretest probability of passing an SBT.

TRIAL REGISTRY

PROSPERO; No.: CRD42020149196; URL: www.crd.york.ac.uk/prospero/.

Adherence of Clinical Practice Guidelines for Pharmacologic Treatments of Hospitalized Patients With COVID-19 to Trustworthy Standards: A Systematic Review

IMPORTANCE

The COVID-19 pandemic created the need for rapid and urgent guidance for clinicians to manage COVID-19 among patients and prevent transmission.

OBJECTIVE

To appraise the quality of clinical practice guidelines (CPGs) using the National Academy of Medicine (NAM) criteria.

EVIDENCE REVIEW

A search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials to December 14, 2020, and a search of related articles to February 28, 2021, that included CPGs developed by societies or by government or nongovernment organizations that reported pharmacologic treatments of hospitalized patients with COVID-19. Teams of 2 reviewers independently abstracted data and assessed CPG quality using the 15-item National Guideline Clearinghouse Extent of Adherence to Trustworthy Standards (NEATS) instrument.

FINDINGS

Thirty-two CPGs were included in the review. Of these, 25 (78.1%) were developed by professional societies and emanated from a single World Health Organization (WHO) region. Overall, the CPGs were of low quality. Only 7 CPGs (21.9%) reported funding sources, and 12 (37.5%) reported conflicts of interest. Only 5 CPGs (15.6%) included a methodologist, described a search strategy or study selection process, or synthesized the evidence. Although 14 CPGs (43.8%) made recommendations or suggestions for or against treatments, they infrequently rated confidence in the quality of the evidence (6 of 32 [18.8%]), described potential benefits and harms (6 of 32 [18.8%]), or graded the strength of the recommendations (5 of 32 [15.6%]). External review, patient or public perspectives, or a process for updating were rare. High-quality CPGs included a methodologist and multidisciplinary collaborations involving investigators from 2 or more WHO regions.

CONCLUSIONS AND RELEVANCE

In this review, few COVID-19 CPGs met NAM standards for trustworthy guidelines. Approaches that prioritize engagement of a methodologist and multidisciplinary collaborators from at least 2 WHO regions may lead to the production of fewer, high-quality CPGs that are poised for updates as new evidence emerges.

TRIAL REGISTRATION

PROSPERO Identifier: CRD42021245239.

Non-invasive ventilation versus invasive weaning in critically ill adults: a systematic review and meta-analysis

BACKGROUND

Extubation to non-invasive ventilation (NIV) has been investigated as a strategy to wean critically ill adults from invasive ventilation and reduce ventilator-related complications.

METHODS

We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, proceedings of four conferences and bibliographies (to June 2020) for randomised and quasi-randomised trials that compared extubation with immediate application of NIV to continued invasive weaning in intubated adults and reported mortality (primary outcome) or other outcomes. Two reviewers independently screened citations, assessed trial quality and abstracted data.

RESULTS

We identified 28 trials, of moderate-to-good quality, involving 2066 patients, 44.6% with chronic obstructive pulmonary disease (COPD). Non-invasive weaning significantly reduced mortality (risk ratio (RR) 0.57, 95% CI 0.44 to 0.74; high quality), weaning failures (RR 0.59, 95% CI 0.43 to 0.81; high quality), pneumonia (RR 0.30, 95% CI 0.22 to 0.41; high quality), intensive care unit (ICU) (mean difference (MD) -4.62 days, 95% CI -5.91 to -3.34) and hospital stay (MD -6.29 days, 95% CI -8.90 to -3.68). Non-invasive weaning also significantly reduced the total duration of ventilation, duration of invasive ventilation and duration of ventilation related to weaning (MD -0.57, 95% CI -1.08 to -0.07) and tracheostomy rate. Mortality, pneumonia, reintubation and ICU stay were significantly lower in trials enrolling COPD (vs mixed) populations.

CONCLUSION

Non-invasive weaning significantly reduced mortality, pneumonia and the duration of ventilation related to weaning, particularly in patients with COPD. Beneficial effects are less clear (or more careful patient selection is required) in non-COPD patients.

PROSPERO REGISTRATION NUMBER

CRD42020201402.

Separation from mechanical ventilation and survival after spinal cord injury: a systematic review and meta-analysis

Background

Prolonged need for mechanical ventilation greatly impacts life expectancy of patients after spinal cord injury (SCI). Weaning outcomes have never been systematically assessed. In this systematic review and meta-analysis, we aimed to investigate the probability of weaning success, duration of mechanical ventilation, mortality, and their predictors in mechanically ventilated patients with SCI.

Methods

We searched six databases from inception until August 2021 for randomized-controlled trials and observational studies enrolling adult patients (≥ 16 years) with SCI from any cause requiring mechanical ventilation. Titles and abstracts were screened independently by two reviewers. Full texts of the identified articles were then assessed for eligibility. Data were extracted independently and in duplicate by pairs of authors, using a standardized data collection form. Synthetic results are reported as meta-analytic means and proportions, based on random effects models.

Results

Thirty-nine studies (14,637 patients, mean age 43) were selected. Cervical lesions were predominant (12,717 patients had cervical lesions only, 1843 in association with other levels’ lesions). Twenty-five studies were conducted in intensive care units (ICUs), 14 in rehabilitative settings.

In ICU, the mean time from injury to hospitalization was 8 h [95% CI 7–9], mean duration of mechanical ventilation 27 days [20–34], probability of weaning success 63% [45–78] and mortality 8% [5–11]. Patients hospitalized in rehabilitation centres had a greater number of high-level lesions (C3 or above), were at 40 days [29–51] from injury and were ventilated for a mean of 97 days [65–128]; 82% [70–90] of them were successfully weaned, while mortality was 1% [0–19].

Conclusions

Although our study highlights the lack of uniform definition of weaning success, of clear factors associated with weaning outcomes, and of high-level evidence to guide optimal weaning in patients with SCI, it shows that around two-thirds of mechanically ventilated patients can be weaned in ICU after SCI. A substantial gain in weaning success can be obtained during rehabilitation, with additional duration of stay but minimal increase in mortality. The study is registered with PROSPERO (CRD42020156788).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00938-x.

Utilization and effect of neuromuscular blockade in a randomized trial of high-frequency oscillation

PURPOSE

We evaluated characteristics associated with neuromuscular blockade (NMB) use, center-level variation, and whether NMB mediated excess mortality among patients assigned to high-frequency oscillatory ventilation (HFOV) in the OSCILLATE trial.

MATERIALS AND METHODS

NMB exposure was defined as receipt after randomization; the primary outcome was hospital mortality. Descriptive analyses compared NMB-exposed vs unexposed patients. Multivariable analyses included patients not on baseline NMB. Cox regression evaluated associations of patient- and center-level variables with NMB use. A log-normal frailty model evaluated center effects. Mediation analysis examined the effect of NMB in HFOV-assigned patients.

RESULTS

376/548 patients (39 centers) received post-randomization NMB, of whom 165 received baseline NMB. Patients receiving post-randomization NMB (vs. not) had worse lung mechanics and gas exchange, received more sedation and vasopressors (p < 0.05), and had higher hospital mortality (44% vs. 34%, p = 0.03). Mean airway pressure ≥ 24 cmH₂O, randomization to HFOV, and intensive care unit size ≥ 31 beds were associated with post-randomization NMB. After adjustment, center had a negligible effect on post-randomization NMB (median hazard ratio 1.01, p = 0.047). NMB use did not mediate excess mortality among HFOV-allocated patients (p = 0.80).

CONCLUSIONS

In OSCILLATE, receipt of post-randomization NMB was associated with worse outcomes, but NMB use did not mediate HFOV-associated higher mortality.

Comparative Effectiveness of Protective Ventilation Strategies for Moderate and Severe Acute Respiratory Distress Syndrome. A Network Meta-Analysis

Rationale: Choosing the best ventilation strategy for acute respiratory distress syndrome (ARDS) is complex, yet it is highly relevant to clinicians during a respiratory pandemic. Objectives: To compare the effects of low Vt, high Vt, high positive end-expiratory pressure (PEEP), prone ventilation, high-frequency oscillation, and venovenous extracorporeal membrane oxygenation (VV ECMO) on mortality in ARDS. Methods: We performed a network meta-analysis of randomized trials. We applied the Grading of Recommendations Assessment, Development and Evaluation methodology to discern the relative effect of interventions on mortality. Measurements and Main Results: We analyzed 34 trials including 9,085 adults with primarily moderate-to-severe ARDS (median baseline Pa_O2/Fi_O2, 118; interquartile range, 110-143). Prone positioning combined with low Vt was the best strategy (risk ratio [RR], 0.74 [95% confidence interval (CI), 0.60-0.92] vs. low Vt; high certainty). VV ECMO was also rated among the best (RR, 0.78 [95% CI, 0.58-1.05] vs. low Vt; RR, 0.66; [95% CI, 0.49-0.88] vs. high Vt) but was rated with lower certainty because VV ECMO was restricted to very severe ARDS (mean baseline Pa_O2/Fi_O2<75). High PEEP combined with low Vt was rated intermediately (RR, 0.91 [95% CI, 0.81-1.03] vs. low Vt; low certainty; RR, 0.77 [95% CI, 0.65-0.91] vs. high Vt; moderate certainty). High Vt was rated worst (RR, 1.19 [95% CI, 1.02-1.37] vs. low Vt; moderate certainty), and we found no support for high-frequency oscillation or high Vt with prone ventilation. Conclusions: These findings suggest that combining low Vt with prone ventilation is associated with the greatest reduction in mortality for critically ill adults with moderate-to-severe ARDS.

Frailty and pre-frailty in cardiac surgery: a systematic review and meta-analysis of 66,448 patients

BACKGROUND

The burden of frailty on cardiac surgical outcomes is incompletely understood. Here we perform a systematic review and meta-analysis of studies comparing frail versus pre-frail versus non-frail patients following cardiac surgery.

METHODS

We searched MEDLINE and EMBASE databases until July 2018 for studies comparing cardiac surgery outcomes in "frail", "pre-frail" and "non-frail" patients. Data was extracted in duplicate. Primary outcome was operative mortality.

RESULTS

There were 19 observational studies with 66,448 patients. Frail patients were more likely female (risk ratio [RR]1.7; 95%CI:1.5-1.9), older (mean difference: 2.4; 95%CI:1.3-3.5 years older) with greater comorbidities and higher STS-PROM. Frailty (RR2.35; 95%CI:1.57-3.51; p < 0.0001) and pre-frailty (RR2.03; 95%CI:1.52-2.70; p < 0.00001) were associated with increased operative mortality compared with non-frail patients. Frailty was also associated with greater risk of prolonged hospital stay (RR1.83; 95%CI:1.61-2.08; p < 0.0001) and intermediate care facility discharge (RR2.71; 95%CI:1.45-5.05; p = 0.002). Frail (Hazard Ratio [HR]3.27; 95%CI:1.93-5.55; p < 0.0001) and pre-frail patients (HR2.30; 95%CI:1.29-4.09; p = 0.005) had worse mid-term mortality (median follow-up 1 years [range 0.5-4 years]). After adjustment for baseline imbalances, frailty was still associated with greater operative mortality (odds ratio [OR]1.97; 95%CI:1.51-2.57; p < 0.00001), intermediate care facility discharge (OR4.61; 95%CI:2.78-7.66; p < 0.00001) and midterm mortality (HR1.37; 95%CI:1.03-1.83; p = 0.03).

CONCLUSION

In patients undergoing cardiac surgery, frailty and pre-frailty were associated with 2-fold and 1.5-fold greater adjusted operative mortality, respectively, greater adjusted perioperative complications and frailty was associated with almost 5-fold risk of non-home discharge. Burden of frailty and pre-frailty on cardiac surgical outcomes.

Meta-Analysis of Safety and Efficacy of Direct Oral Anticoagulants Versus Warfarin According to Time in Therapeutic Range in Atrial Fibrillation

Among atrial fibrillation (AF) patients, it is unclear whether the efficacy and safety of direct oral anticoagulants (DOAC) relative to warfarin is consistent across various levels of international normalized ratio (INR) control. To determine the efficacy and safety of DOAC agents compared with warfarin for patients with various levels of anticoagulation control as reflected by their time in therapeutic range (TTR), we conducted a systematic review and meta-analysis of published randomized controlled trials of DOAC versus (vs) warfarin which reported outcomes stratified by TTR. Based on reported center-based TTR (cTTR) ranges, degrees of INR control were categorized into 3 cTTR strata: low (<60%), intermediate (60% to 66%), and high (>66%). Pooled hazard ratios (HR) and 95% confidence intervals (CI) were determined for stroke or systemic embolism (SSE), major bleeding, and intracranial hemorrhage (ICH). Across all cTTR strata, DOAC-treated patients had lower risk of SSE versus warfarin, with a HR of 0.73 (95% CI 0.61 to 0.88) for the low, 0.76 (95% CI 0.59 to 0.98) intermediate; and 0.78 (95% CI 0.63 to 0.96) high cTTR subgroups. Compared with warfarin, DOAC-treated patients had lower risk of major bleeding in the low and intermediate cTTR strata, and similar risk in the highest cTTR stratum (HR 1.00, 95% CI 0.80 to 1.26). Patients treated with DOAC had lower risk of ICH compared with warfarin (HR 0.55, 95% CI; 0.40 to 0.74) which was observed across all cTTR strata. In conclusion, regardless of the degree of INR control, DOAC agents are preferable over warfarin as stroke prevention therapy for patients with AF.

Resumption of Cardiac Activity after Withdrawal of Life-Sustaining Measures

BACKGROUND

The minimum duration of pulselessness required before organ donation after circulatory determination of death has not been well studied.

METHODS

We conducted a prospective observational study of the incidence and timing of resumption of cardiac electrical and pulsatile activity in adults who died after planned withdrawal of life-sustaining measures in 20 intensive care units in three countries. Patients were intended to be monitored for 30 minutes after determination of death. Clinicians at the bedside reported resumption of cardiac activity prospectively. Continuous blood-pressure and electrocardiographic (ECG) waveforms were recorded and reviewed retrospectively to confirm bedside observations and to determine whether there were additional instances of resumption of cardiac activity.

RESULTS

A total of 1999 patients were screened, and 631 were included in the study. Clinically reported resumption of cardiac activity, respiratory movement, or both that was confirmed by waveform analysis occurred in 5 patients (1%). Retrospective analysis of ECG and blood-pressure waveforms from 480 patients identified 67 instances (14%) with resumption of cardiac activity after a period of pulselessness, including the 5 reported by bedside clinicians. The longest duration after pulselessness before resumption of cardiac activity was 4 minutes 20 seconds. The last QRS complex coincided with the last arterial pulse in 19% of the patients.

CONCLUSIONS

After withdrawal of life-sustaining measures, transient resumption of at least one cycle of cardiac activity after pulselessness occurred in 14% of patients according to retrospective analysis of waveforms; only 1% of such resumptions were identified at the bedside. These events occurred within 4 minutes 20 seconds after a period of pulselessness. (Funded by the Canadian Institutes for Health Research and others.).

Patient harm associated with serial phlebotomy and blood waste in the intensive care unit: A retrospective cohort study

Background

Intensive care unit (ICU) patients are at high risk of anemia, and phlebotomy is a potentially modifiable source of blood loss. Our objective was to quantify daily phlebotomy volume for ICU patients, including blood discarded as waste during vascular access, and evaluate the impact of phlebotomy volume on patient outcomes.

Methods

This was a retrospective observational cohort study between September 2014 and August 2015 at a tertiary care academic medical-surgical ICU. A prospective audit of phlebotomy practices in March 2018 was used to estimate blood waste during vascular access. Multivariable logistic regression was used to evaluate phlebotomy volume as a predictor of ICU nadir hemoglobin < 80 g/L, and red blood cell transfusion.

Results

There were 428 index ICU admissions, median age 64.4 yr, 41% female. Forty-four patients (10%) with major bleeding events were excluded. Mean bedside waste per blood draw (144 draws) was: 3.9 mL from arterial lines, 5.5 mL central venous lines, and 6.3 mL from peripherally inserted central catheters. Mean phlebotomy volume per patient day was 48.1 ± 22.2 mL; 33.1 ± 15.0 mL received by the lab and 15.0 ± 8.1 mL discarded as bedside waste. Multivariable regression, including age, sex, admission hemoglobin, sequential organ failure assessment score, and ICU length of stay, showed total daily phlebotomy volume was predictive of hemoglobin <80 g/L (p = 0.002), red blood cell transfusion (p<0.001), and inpatient mortality (p = 0.002). For every 5 mL increase in average daily phlebotomy the odds ratio for nadir hemoglobin <80 g/L was 1.18 (95% CI 1.07–1.31) and for red blood cell transfusion was 1.17 (95% CI 1.07–1.28).

Conclusion

A substantial portion of daily ICU phlebotomy is waste discarded during vascular access. Average ICU phlebotomy volume is independently associated with ICU acquired anemia and red blood cell transfusion which supports the need for phlebotomy stewardship programs.

Duration of diaphragmatic inactivity after endotracheal intubation of critically ill patients

BACKGROUND

In patients intubated for mechanical ventilation, prolonged diaphragm inactivity could lead to weakness and poor outcome. Time to resume a minimal diaphragm activity may be related to sedation practice and patient severity.

METHODS

Prospective observational study in critically ill patients. Diaphragm electrical activity (EAdi) was continuously recorded after intubation looking for resumption of a minimal level of diaphragm activity (beginning of the first 24 h period with median EAdi > 7 µV, a threshold based on literature and correlations with diaphragm thickening fraction). Recordings were collected until full spontaneous breathing, extubation, death or 120 h. A 1 h waveform recording was collected daily to identify reverse triggering.

RESULTS

Seventy-five patients were enrolled and 69 analyzed (mean age ± standard deviation 63 ± 16 years). Reasons for ventilation were respiratory (55%), hemodynamic (19%) and neurologic (20%). Eight catheter disconnections occurred. The median time for resumption of EAdi was 22 h (interquartile range 0-50 h); 35/69 (51%) of patients resumed activity within 24 h while 4 had no recovery after 5 days. Late recovery was associated with use of sedative agents, cumulative doses of propofol and fentanyl, controlled ventilation and age (older patients receiving less sedation). Severity of illness, oxygenation, renal and hepatic function, reason for intubation were not associated with EAdi resumption. At least 20% of patients initiated EAdi with reverse triggering.

CONCLUSION

Low levels of diaphragm electrical activity are common in the early course of mechanical ventilation: 50% of patients do not recover diaphragmatic activity within one day. Sedatives are the main factors accounting for this delay independently from lung or general severity. Trial Registration ClinicalTrials.gov (NCT02434016). Registered on April 27, 2015. First patients enrolled June 2015.

Compliance With Evidence-Based Processes of Care After Transitions Between Staff Intensivists

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.

Sleep Fragmentation and Cognitive Trajectories After Critical Illness

BACKGROUND

ICU survivors can experience both cognitive dysfunction and persistent sleep disturbances after hospitalization. Sleep disturbances have been linked with cognitive impairment in various patient populations, and the apolipoprotein E (APOE) genotype has been linked to sleep-related impairments in cognition.

RESEARCH QUESTION

Is there an association between sleep, long-term cognition, and APOE status in ICU survivors?

STUDY DESIGN AND METHODS

We enrolled 150 patients from five centers who had been mechanically ventilated for at least 3 days; 102 patients survived to ICU discharge. Actigraphy and cognitive testing were undertaken at 7 days, 6 months, and 12 months after ICU discharge, and sleep duration, quality, and timing were estimated by actigraphy. APOE single nucleotide polymorphisms were assessed for each patient.

RESULTS

Actigraphy-estimated sleep fragmentation, but not total sleep time or interdaily stability (estimate of circadian rhythmicity), was associated with worse cognitive impairment at 7 days of ICU discharge. No actigraphy-estimated variable of sleep estimation at 7 days post-ICU discharge predicted cognitive impairment or persistent sleep abnormalities at 6 and 12 months of follow-up in subsequently assessed survivors. Possessing the APOE ε4 allele was not significantly associated with sleep disturbances and its presence did not modify the risk of sleep-related cognitive impairment at follow-up.

INTERPRETATION

Sleep fragmentation estimated by actigraphy was associated with worse cognitive performance in hospital, but not at later time intervals. Further research is needed to better delineate the relationship between persistent sleep disturbances and cognition in larger numbers of ICU survivors.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT02086877; URL: www.clinicaltrials.gov.

Role Incongruence and Psychological Stress Symptoms in Substitute Decision Makers of Intensive Care Patients

BACKGROUND

Most intensive care patients require substitute decision makers (SDMs) to make decisions. The SDMs may prefer an active, shared, or passive decision-making role. Role incongruence is when preferred and actual roles differ.

OBJECTIVE

To evaluate the impact of decision-making role preferences and role incongruence on psychological distress symptoms in SDMs.

METHODS

A multicenter, interviewer-administered survey was conducted among SDMs of critically ill adults. The Control Preferences Scale was used to evaluate role preferences. Psychological distress was defined as anxiety, depression, or posttraumatic stress symptoms with predefined cut points on the Hospital Anxiety and Depression Scale (score > 10 on the anxiety or the depression subscale) and Impact of Events Scale (score > 30).

RESULTS

One hundred eighty SDMs were recruited; 64% responded. Most were white (71%) and female (65%); 46% were spouses. Role preferences varied: active, 24%; shared, 44%; and passive, 31%. Almost half (49%) reported incongruence. Symptom prevalence was 50% for posttraumatic stress, 32% for anxiety, and 16% for depression. Most (56%) reported some psychological distress. In multivariable logistic regression, the composite outcome of psychological distress was independently associated with patient death (odds ratio, 2.95; 95% CI, 1.08-8.02; P = .03), female sex of SDM (odds ratio, 2.96; 95% CI, 1.49-5.89; P = .002), and incongruence (odds ratio, 3.26; 95% CI, 1.67-6.36; P < .001).

CONCLUSIONS

Adverse psychological symptoms are prevalent in SDMs of critically ill patients and are related to role incongruence.

Mitral valve prosthesis choice in patients <70 years: A systematic review and meta-analysis of 20 219 patients

BACKGROUND

The optimal mitral prosthesis in young patients is unclear. This systematic review and meta-analysis were performed to compare outcomes between bileaflet mechanical mitral valve replacement (mMVR) and bioprosthesis mitral valve replacement (bioMVR) for MVR patients aged less than 70 years.

METHODS

We searched MEDLINE and EMBASE databases from inception to July 2018 for studies comparing surgical outcomes of mMVR vs bioMVR.

RESULTS

There were 14 observational studies with 20 219 patients (n = 14 658 mMVR and n = 5561 bioMVR). Patients receiving an mMVR were younger with fewer comorbidities including renal failure, dialysis, and less-infective endocarditis (P < .001). The estimated 10-year mortality ranged from 19% to 49% for mMVR and 22% to 58% for bioMVR among studies. Comparing matched or adjusted data, mMVR was associated with lower operative (risk ratio [RR]: 0.61; 95% confidence interval [CI]: 0.39, 0.94; P = .03) and long-term (HR: 0.81; 95% CI: 0.71, 0.92; P = .002) mortality at a median follow-up of 8 years (IQR: 6-10 years). Estimated 10-year risk for mitral valve reoperation ranged from 0% to 8% for mMVR and 8% to 22% for bioMVR among matched/adjusted studies. mMVR was associated with lower matched/adjusted risk of reoperation (HR: 0.35; 95% CI: 0.19, 0.65; P = .001) but with greater risk of bleeding (HR: 1.59; 95% CI: 1.19, 2.13; P = .002) and a trend to greater risk of stroke and embolism (HR: 1.70; 95% CI: 0.92, 3.15; P = .09).

CONCLUSION

Mechanical MVR in patients aged less than 70 years is associated with a lower risk of operative mortality as well as a 20% lower risk of long-term death and 65% lower risk of mitral valve reoperation but 60% greater risk of bleeding compared with bioMVR in matched or adjusted data.

Valve-Sparing Root Replacement Versus Composite Valve Grafting in Aortic Root Dilation: A Meta-Analysis

BACKGROUND

Aortic valve-sparing operations theoretically have fewer stroke and bleeding complications but may increase late reoperation risk versus composite valve grafts.

METHODS

We meta-analyzed all studies comparing aortic valve-sparing (reimplantation and remodelling) and composite valve-grafting (bioprosthetic and mechanical) procedures. Early outcomes were all-cause mortality, reoperation for bleeding, myocardial infarction, and thromboembolism/stroke. Long-term outcomes included all-cause mortality, reintervention, bleeding, and thromboembolism/stroke. Studies exclusively investigating dissection or pediatric populations were excluded.

RESULTS

A total of 3794 patients who underwent composite valve grafting and 2424 who underwent aortic valve-sparing procedures were included from 9 adjusted and 17 unadjusted observational studies. Mean follow-up was 5.8 ± 3.0 years. Aortic valve sparing was not associated with any difference in early mortality, bleeding, myocardial infarction, or thromboembolic complications. Late mortality was significantly lower after valve sparing (incident risk ratio, 0.68; 95% confidence interval [CI], 0.54-0.87; P < .01). Late thromboembolism/stroke (incident rate ratio, 0.36; 95% CI, 0.22-0.60; P < .01) and bleeding (incident rate ratio, 0.21; 95% CI, 0.11-0.42; P < .01) risks were lower after valve sparing. Procedure type did not affect late reintervention.

CONCLUSIONS

Aortic valve sparing appears to be safe and associated with reduced late mortality, thromboembolism/stroke, and bleeding compared with composite valve grafting. Late durability is equivalent. Aortic valve sparing should be considered in patients with favorable aortic valve morphology.

Supplemental Cardioplegia During Donor Heart Implantation: A Systematic Review and Meta-Analysis

BACKGROUND

The optimal donor heart preservation and management strategy during heart transplantation remains controversial. We report the results of a systematic review and meta-analysis of the effect of supplemental cardioplegia administration during donor heart implant for transplantation.

METHODS

We searched MEDLINE and Embase databases until February 2019 for studies comparing patients who received transplants with the donor heart given supplemental cardioplegia or not. Data were extracted by 2 independent investigators. The main outcomes were early morbidity and mortality.

RESULTS

Included were 7 retrospective observational studies (4 comparing to historical controls) and 3 randomized controlled trials enrolling 1125 patients. Supplemental cardioplegia included crystalloid and blood cardioplegia given continuous retrograde or as terminal "hot shots." Supplemental cardioplegia was associated with improved early mortality (risk ratio [RR], 0.55; 95% confidence interval [CI], 0.35-0.87; P < .01), greater rates of spontaneous return of sinus rhythm (RR, 2.62; 95% CI, 1.50-4.56; P < .01), shorter intensive care stay (mean difference, -3.4 days; 95% CI, -5.1 to -1.6; P < .01), and lower incidence of ischemic changes seen on endomyocardial biopsy specimens (RR, 0.49; 95% CI, 0.35-0.69; P < .01) compared with controls. Midterm mortality was not different between groups (incident rate ratio, 0.80; 95% CI, 0.51-1.26; P = .34).

CONCLUSIONS

Administration of supplemental cardioplegia may be associated with a reduction in organ ischemic injury and shorter intensive care stay as well as improvement in early survival after transplantation. This strategy may be a simple and cost-effective adjunct to improve outcomes of heart transplantation, especially in an era of increasing use of marginal donor organs. Further investigation will be needed to confirm the findings of this hypothesis-generating study.

Predicting mortality among critically ill patients with acute kidney injury treated with renal replacement therapy: Development and validation of new prediction models

PURPOSE

Severe acute kidney injury (AKI) is associated with a significant risk of mortality and persistent renal replacement therapy (RRT) dependence. The objective of this study was to develop prediction models for mortality at 90-day and 1-year following RRT initiation in critically ill patients with AKI.

METHODS

All patients who commenced RRT in the intensive care unit for AKI at a tertiary care hospital between 2007 and 2014 constituted the development cohort. We evaluated the external validity of our mortality models using data from the multicentre OPTIMAL-AKI study.

RESULTS

The development cohort consisted of 594 patients, of whom 320(54%) died and 40 (15% of surviving patients) remained RRT-dependent at 90-day Eleven variables were included in the model to predict 90-day mortality (AUC:0.79, 95%CI:0.76-0.82). The performance of the 90-day mortality model declined upon validation in the OPTIMAL-AKI cohort (AUC:0.61, 95%CI:0.54-0.69) and showed modest calibration. Similar results were obtained for mortality model at 1-year.

CONCLUSIONS

Routinely collected variables at the time of RRT initiation have limited ability to predict mortality in critically ill patients with AKI who commence RRT.

Many continuous variables should be analyzed using the relative scale: a case study of β2-agonists for preventing exercise-induced bronchoconstriction

BACKGROUND

The relative scale adjusts for baseline variability and therefore may lead to findings that can be generalized more widely. It is routinely used for the analysis of binary outcomes but only rarely for continuous outcomes. Our objective was to compare relative vs absolute scale pooled outcomes using data from a recently published Cochrane systematic review that reported only absolute effects of inhaled β₂-agonists on exercise-induced decline in forced-expiratory volumes in 1 s (FEV₁).

METHODS

From the Cochrane review, we selected placebo-controlled cross-over studies that reported individual participant data (IPD). Reversal in FEV₁ decline after exercise was modeled as a mean uniform percentage point (pp) change (absolute effect) or average percent change (relative effect) using either intercept-only or slope-only, respectively, linear mixed-effect models. We also calculated the pooled relative effect estimates using standard random-effects, inverse-variance-weighting meta-analysis using study-level mean effects.

RESULTS

Fourteen studies with 187 participants were identified for the IPD analysis. On the absolute scale, β₂-agonists decreased the exercise-induced FEV₁ decline by 28 pp., and on the relative scale, they decreased the FEV₁ decline by 90%. The fit of the statistical model was significantly better with the relative 90% estimate compared with the absolute 28 pp. estimate. Furthermore, the median residuals (5.8 vs. 10.8 pp) were substantially smaller in the relative effect model than in the absolute effect model. Using standard study-level meta-analysis of the same 14 studies, β₂-agonists reduced exercise-induced FEV₁ decline on the relative scale by a similar amount: 83% or 90%, depending on the method of calculating the relative effect.

CONCLUSIONS

Compared with the absolute scale, the relative scale captures more effectively the variation in the effects of β₂-agonists on exercise-induced FEV₁-declines. The absolute scale has been used in the analysis of FEV₁ changes and may have led to sub-optimal statistical analysis in some cases. The choice between the absolute and relative scale should be determined based on biological reasoning and empirical testing to identify the scale that leads to lower heterogeneity.

Clinical outcomes of mitral valve intervention in patients with mitral annular calcification: A systematic review and meta-analysis

BACKGROUND

Mitral valve (MV) disease with mitral annular calcification (MAC) poses a surgical challenge and the clinical outcomes of MV surgery as well as transcatheter mitral valve replacement (TMVR) remain relatively unexplored. We performed a systematic review and meta-analysis to assess the effects of MAC on clinical outcomes following MV surgery and TMVR.

METHODS

We searched MEDLINE and EMBASE databases until February 2019 for studies comparing clinical outcomes of MV surgery or TMVR in patients with and without MAC. Data were extracted by two independent investigators. Outcomes were perioperative and midterm complications and mortality.

RESULTS

Seven observational studies enrolling 2902 patients were included. MAC patients were older, more likely to be female with greater chronic lung disease and kidney failure. Perioperative mortality was similar between patients with and without MAC undergoing MV surgery (risk ratio [RR], 1.15; 95% confidence interval [CI], 0.50-2.65; P = .74). MAC was associated with a higher risk of bleeding, permanent pacemaker implantation, and periprosthetic leak. Midterm mortality was greater in MAC patients undergoing MV surgery (incident rate ratio [IRR], 1.32; 95% CI, 1.05-1.67; P = .02). MAC patients undergoing TMVR had higher perioperative (RR, 4.65; 95% CI, 2.93-7.38; P < .01) and 1-year (RR, 5.44; 95% CI, 3.49-8.49; P < .01) mortality, decreased procedural success, greater left ventricular outflow tract obstruction and need for conversion to surgery when compared with patients undergoing TMVR for dysfunction of a bioprosthetic valve or annuloplasty ring.

CONCLUSION

MV procedures in patients with MAC are associated with higher mortality and morbidity. This is largely driven by the high-risk patient profile associated with MAC. TMVR holds promise but has important limitations and should be reserved for select patients.

Aortic valve replacement with pulmonary hypertension: Meta-analysis of 70 676 patients

BACKGROUND AND AIM OF THE STUDY

We compared early and late outcomes of surgical aortic valve replacement (SAVR) in patients with aortic stenosis (AS) and pulmonary hypertension (PHT).

METHODS

We searched MEDLINE and EMBASE databases until July 2018 for studies comparing patients with AS and none, mild-moderate, or severe PHT undergoing SAVR. Random-effects meta-analysis was performed.

RESULTS

There were 12 observational studies with 70 676 patients with median follow-up 4.0 years (interquartile range, 2.6-4 years). Compared to patients with no PHT, patients with any PHT undergoing SAVR were older (mean difference [MD], 2.31 years; 95% confidence interval [CI], 1.38-3.23 years; P < .01), with greater comorbidities and reduced ejection fraction (MD, -4.36; 95%CI, -5.94 to -2.78; P < .01). Patients with any PHT had higher unadjusted (5.2% vs 2.4%; risk ratio [RR], 2.27; 95%CI, 2.04-2.53; P < .01) and adjusted (RR, 1.65; 95%CI, 1.28-2.14; P < .01) in-hospital mortality compared with no PHT. Severe (RR, 3.53; 95%CI, 1.46-8.54; P < .01) and mild-moderate PHT (RR, 2.13; 95%CI, 1.28-3.55; P < .01) were associated with higher unadjusted in-hospital mortality compared with no PHT. Any PHT was associated with a higher unadjusted risk of stroke (RR, 1.64; 95%CI, 1.42-1.90; P < .01), acute kidney injury (RR, 2.02; 95%CI, 1.50-2.72; P < .01), prolonged ventilation (RR, 1.62; 95%CI, 1.04-2.52; P = .03), and longer hospital stay (MD, 1.76 days; 95%CI, 0.57-2.95; P < .01). Severe (HR, 2.44; 95%CI, 1.60-3.72; P < .01) but not mild-moderate PHT (HR, 2.25; 95%CI, 0.91-5.59; P = .08) was associated with higher adjusted long-term mortality compared with no PHT.

CONCLUSIONS

Patients with severe AS and severe PHT had a significant increase in operative mortality and more than double the risk of long-term mortality following SAVR compared with patients with no PHT. Such patients may benefit from a less invasive transcatheter aortic valve intervention.

Systematic review of contemporary outcomes of endovascular and open thoracoabdominal aortic aneurysm repair

OBJECTIVE

The purpose of the study was to provide a systematic review of the literature reporting the contemporary early outcomes after endovascular and open repair of thoracoabdominal aortic aneurysms (TAAAs).

METHODS

MEDLINE and Embase were searched for studies from January 2006 to March 2018 that reported either endovascular (using branched or fenestrated endografts) or open repair of TAAA in at least 10 patients. Outcomes of interest included perioperative mortality, spinal cord injury (SCI), renal failure requiring dialysis, and stroke. Pooled proportions were determined using a random-effects model.

RESULTS

The analysis included 71 studies, of which 24 and 47 reported outcomes after endovascular and open TAAA repair, respectively. Endovascular cohort patients were older and had higher rates of coronary artery disease, chronic obstructive pulmonary disease, and diabetes. Endovascular repair was associated with higher rates of SCI (13.5%; 95% confidence interval [CI], 10.5%-16.7%) compared with open repair (7.4%; 95% CI, 6.2%-8.7%; P < .01) but similar rates of permanent paralysis (5.2% [95% CI, 3.8%-6.7%] vs 4.4% [95% CI, 3.3%-5.6%]; P = .39), lower rates of postoperative dialysis (6.4% [95% CI, 3.2%-9.5%] vs 12.0% [95% CI, 8.2%-16.3%]; P = .03) but similar rates of being discharged on permanent dialysis (3.7% [95% CI, 2.0%-5.9%] vs 3.8% [95% CI, 2.9%-5.3%]; P = .93), a trend to lower stroke (2.7% [95% CI, 1.9%-3.6%] vs 3.9% [95% CI, 3.0%-4.9%]; P = .06), and similar perioperative mortality (7.4% [95% CI, 5.9%-9.1%] vs 8.9% [95% CI, 7.2%-10.9%]; P = .21).

CONCLUSIONS

This systematic review summarizes the contemporary literature results of endovascular and open TAAA repair. Endovascular repair studies included patients with more comorbidities and were associated with higher rates of SCI but similar rates of permanent paraplegia, whereas open repair studies had higher rates of postoperative dialysis but similar rates of being discharged on permanent dialysis. Perioperative mortality rates were similar. Universally adopted reporting standards for patient characteristics, outcomes, and the conduct of contemporary comparative studies will allow better assessment and comparisons of the risks associated with the two surgical treatment options for TAAA.

Ross Procedure vs Mechanical Aortic Valve Replacement in Adults: A Systematic Review and Meta-analysis

Importance

The ideal aortic valve substitute in young and middle-aged adults remains unknown.

Objective

To compare long-term outcomes between the Ross procedure and mechanical aortic valve replacement in adults.

Data Sources

The Ovid versions of MEDLINE and EMBASE classic (January 1, 1967, to April 26, 2018; search performed on April 27, 2018) were screened for relevant studies using the following text word search in the title or abstract: ("Ross" OR "autograft") AND ("aortic" OR "mechanical").

Study Selection

All randomized clinical trials and observational studies comparing the Ross procedure to the use of mechanical prostheses in adults undergoing aortic valve replacement were included. Studies were included if they reported any of the prespecified primary or secondary outcomes. Studies were excluded if no clinical outcomes were reported or if data were published only as an abstract. Citations were screened in duplicate by 2 of the authors, and disagreements regarding inclusion were reconciled via consensus.

Data Extraction and Synthesis

This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-analysis of Observational Studies in Epidemiology guidelines. Data were independently abstracted by 3 reviewers and pooled using a random-effects model.

Main Outcomes and Measures

The prespecified primary outcome was all-cause mortality.

Results

The search identified 2919 reports, of which 18 studies (3516 patients) met inclusion criteria, including 1 randomized clinical trial and 17 observational studies, with a median average follow-up of 5.8 (interquartile range, 3.4-9.2) years. Analysis of the primary outcome showed a 46% lower all-cause mortality in patients undergoing the Ross procedure compared with mechanical aortic valve replacement (incidence rate ratio [IRR], 0.54; 95% CI, 0.35-0.82; P = .004; I2 = 28%). The Ross procedure was also associated with lower rates of stroke (IRR, 0.26; 95% CI, 0.09-0.80; P = .02; I2 = 8%) and major bleeding (IRR, 0.17; 95% CI, 0.07-0.40; P < .001; I2 = 0%) but higher rates of reintervention (IRR, 1.76; 95% CI, 1.16-2.65; P = .007; I2 = 0%).

Conclusions and Relevance

Data from primarily observational studies suggest that the Ross procedure is associated with lower all-cause mortality compared with mechanical aortic valve replacement. These findings highlight the need for a large, prospective randomized clinical trial comparing long-term outcomes between these 2 interventions.

Tricuspid valve intervention at the time of mitral valve surgery: a meta-analysis

OBJECTIVES

The surgical management of tricuspid regurgitation (TR) at the time of mitral valve surgery remains controversial. Our objectives were to determine the safety and efficacy of tricuspid valve (TV) repair during mitral valve surgery in a meta-analysis.

METHODS

MEDLINE and EMBASE were searched from 1946 to 2017 for all studies comparing TV repair to no intervention at the time of mitral valve surgery on early and late mortality and late TR. A random-effects meta-analysis of all outcomes was performed.

RESULTS

One thousand four hundred and seventeen studies were retrieved and a total of 17 studies [2 randomized clinical trial (n = 211), 11 adjusted observational studies (n = 3848) and 4 unadjusted observational studies (n = 67 010)] that compared TV repair (n = 11 787) to no intervention (n = 56 027) at a mean follow-up of 6.0 ± 0.64 years were included. There was no difference in 30-day/in-hospital mortality between repair and no repair [risk ratio (RR) 1.19, 95% confidence interval (95% CI) 0.70-2.02; P = 0.52]. The incidence of new permanent pacemaker implantation was higher in the TV repair group (RR 2.73, 95% CI 2.57-2.89; P < 0.01). TV repair was protective against late moderate or greater TR [incident rate ratio (IRR) 0.28, 95% CI 0.17-0.47; P < 0.01] and severe TR (IRR 0.38, 95% CI 0.17-0.84). There was a numerically lower rate of late TV reoperation (IRR 0.39, 95% CI 0.12-1.25; P = 0.11) that did not reach statistical significance. Overall, there was no difference in late mortality between the 2 treatments (IRR 0.87, 95% CI 0.63-1.24; P = 0.43).

CONCLUSIONS

TV repair appears safe in the perioperative period and may reduce future recurrent TR without any survival benefit.

Management of Less-Than-Severe Aortic Stenosis During Coronary Bypass: A Systematic Review and Meta-Analysis

OBJECTIVE

The management of concomitant mild-to-moderate aortic stenosis (AS) at the time of coronary artery bypass graft (CABG) is controversial. Here we perform a systematic review and meta-analysis of CABG and aortic valve replacement (AVR) versus CABG alone in patients with mild-moderate AS.

METHODS

We searched MEDLINE and EMBASE databases until July 2018 for studies comparing CABG & AVR versus CABG in patients with mild-moderate AS undergoing coronary bypass. Data were extracted by 2 independent investigators. The main outcomes were operative mortality, long-term survival, and reintervention for AS.

RESULTS

There were 6 unmatched retrospective observational studies with 1,172 patients (median follow-up 4.7 [interquartile range: 4.3 to 5.3] years). Patients undergoing CABG & AVR had less severe coronary artery disease. There were no differences in operative mortality (relative risk [RR]: 1.07; 95% CI, 0.59 to 1.94; P = 0.8). CABG & AVR was associated with greater incidence of stroke, bleeding, renal failure, and mediastinitis. At median follow-up of 5 years, there was no difference in long-term mortality (incidence rate ratio [IRR]:1.44; 95% CI, 0.83 to 2.51; P = 0.19), but CABG & AVR was associated with 73% lower risk of reoperation for AS (n = 13/485 versus n = 71/702; IRR: 0.27; 95% CI, 0.14 to 0.51; P < 0.001).

CONCLUSIONS

In patients undergoing CABG with mild-moderate AS, combining AVR with CABG was associated with no difference in operative mortality but with increased risk of stroke, bleeding, renal failure, and mediastinitis. Long-term mortality was not different, but a risk of reoperation for AS at 5 years was 73% lower. Given the increasingly wide availability and safety of transcatheter aortic valve replacement (TAVR), one may consider a conservative approach toward concomitant mild-moderate AS.

Early vs Late Surgery for Patients With Endocarditis and Neurological Injury: A Systematic Review and Meta-analysis

BACKGROUND

Surgical timing in infective endocarditis (IE) with preoperative neurological events remains controversial. The relevant society guidelines are each on the basis of a small number of observational studies. This meta-analysis was designed to search the available literature broadly and assess the weight of available evidence as comprehensively as possible.

METHODS

We searched MEDLINE and EMBASE to April 2018 for studies that compared mortality or neurological exacerbation in early vs late surgery for IE complicated by neurological events. Random effects meta-analysis was performed.

RESULTS

Twenty-seven observational studies (25 unadjusted, n = 879; 2 adjusted, n = 451) met inclusion criteria. Using early and late thresholds defined in each study (7 or 14 days), early surgery in ischemic or hemorrhagic stroke was associated with elevated perioperative mortality vs late surgery (pooled relative risk [RR], 1.74; 95% confidence interval, 1.34-2.25; P < 0.0001; I² = 0%) and greater neurological exacerbation (RR, 2.09; 95% confidence interval, 1.32-3.32; P = 0.002; I² = 33%). In subgroup analysis, for ischemic stroke, early surgery before 7 vs before 14 days exhibited similar perioperative mortality and neurological exacerbation. For hemorrhagic stroke, performing surgery before 21 vs before 28 days showed trends toward perioperative mortality (RR, 1.77 vs 0.63, interaction P = 0.14) and neurological (RR, 2.02 vs RR, 0.44; interaction P = 0.11) exacerbation. There was no difference in long-term mortality but reporting was sparse. Early surgery was often performed for clinical deterioration, negatively biasing outcomes.

CONCLUSIONS

Available observational data support delaying surgery by 7-14 days if possible in IE complicated by ischemic stroke and > 21 days in hemorrhagic stroke to decrease perioperative mortality and neurological exacerbation rates. Randomized trials are needed for definitive guidance.

Determinants of Depressive Symptoms at 1 Year Following ICU Discharge in Survivors of ≥ 7 Days of Mechanical Ventilation: Results From the RECOVER Program, a Secondary Analysis of a Prospective Multicenter Cohort Study

BACKGROUND

Moderate to severe depressive symptoms occur in up to one-third of patients at 1 year following ICU discharge, negatively affecting patient outcomes. This study evaluated patient and caregiver factors associated with the development of these symptoms.

METHODS

This study used the Rehabilitation and Recovery in Patients after Critical Illness and Their Family Caregivers (RECOVER) Program (Phase 1) cohort of 391 patients from 10 medical/surgical university-affiliated ICUs across Canada. We determined the association between patient depressive symptoms (captured by using the Beck Depression Inventory II [BDI-II]), patient characteristics (age, sex, socioeconomic status, Charlson score, and ICU length of stay [LOS]), functional independence measure (FIM) motor subscale score, and caregiver characteristics (Caregiver Assistance Scale and Center for Epidemiologic Studies-Depression Scale) by using linear mixed models at time points 3, 6, and 12 months.

RESULTS

BDI-II data were available for 246 patients. Median age at ICU admission was 56 years (interquartile range, 45-65 years), 143 (58%) were male, and median ICU LOS was 19 days (interquartile range, 13-32 days). During the 12-month follow-up, 67 of 246 (27.2%) patients had a BDI-II score ≥ 20, indicating moderate to severe depressive symptoms. Mixed models showed worse depressive symptoms in patients with lower FIM motor subscale scores (1.1 BDI-II points per 10 FIM points), lower income status (by 3.7 BDI-II points; P = .007), and incomplete secondary education (by 3.8 BDI-II points; P = .009); a curvilinear relation with age (P = .001) was also reported, with highest BDI-II at ages 45 to 50 years. No associations were found between patient BDI-II and comorbidities (P = .92), sex (P = .25), ICU LOS (P = .51), or caregiver variables (Caregiver Assistance Scale [P = .28] and Center for Epidemiologic Studies Depression Scale [P = .74]).

CONCLUSIONS

Increased functional dependence, lower income, and lower education are associated with increased severity of post-ICU depressive symptoms, whereas age has a curvilinear relation with symptom severity. Knowledge of risk factors may inform surveillance and targeted mental health follow-up. Early mobilization and rehabilitation aiming to improve function may serve to modify mood disorders.

Selection and Receipt of Kidney Replacement in Critically Ill Older Patients with AKI

BACKGROUND AND OBJECTIVES

Older patients in the intensive care unit are at greater risk of AKI; however, use of kidney replacement therapy in this population is poorly characterized. We describe the triggers and outcomes associated with kidney replacement therapy in older patients with AKI in the intensive care unit.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Our study was a prospective cohort study in 16 Canadian hospitals from September 2013 to November 2015. Patients were ≥65 years old, were critically ill, and had severe AKI; exclusion criteria were urgent kidney replacement therapy for a toxin and ESKD. We recorded triggers for kidney replacement therapy (primary exposure), reasons for not receiving kidney replacement therapy, 90-day mortality (primary outcome), and kidney recovery.

RESULTS

Of 499 patients, mean (SD) age was 75 (7) years old, Charlson comorbidity score was 3.0 (2.3), and median (interquartile range) Clinical Frailty Scale score was 4 (3-5). Most were receiving mechanical ventilation (64%; n=319) and vasoactive support (63%; n=314). Clinicians were willing to offer kidney replacement therapy to 361 (72%) patients, and 229 (46%) received kidney replacement therapy. Main triggers for kidney replacement therapy were oligoanuria, fluid overload, and acidemia, whereas main reasons for not receiving therapy were anticipated recovery (67%; n=181) and therapy not consistent with patient preferences for care (24%; n=66). Ninety-day mortality was similar in patients who did and did not receive kidney replacement therapy (50% versus 51%; adjusted hazard ratio, 0.78; 95% confidence interval, 0.58 to 1.06); however, decisions to offer kidney replacement therapy varied significantly by patient mix, acuity, and perceived benefit. There were no differences in health-related quality of life or rehospitalization among survivors.

CONCLUSIONS

Most older, critically ill patients with severe AKI were perceived as candidates for kidney replacement therapy, and approximately one half received therapy. Both willingness to offer kidney replacement therapy and reasons for not starting showed heterogeneity due to a range in patient-specific factors and clinician perceptions of benefit.

A systematic review and meta-analysis of early outcomes after endovascular versus open repair of thoracoabdominal aortic aneurysms

OBJECTIVE

The objective of this study was to compare the early results of endovascular vs open thoracoabdominal aortic aneurysm (TAAA) repair.

METHODS

MEDLINE and Embase were searched for studies from January 2006 to March 2018 that compared endovascular vs open repair of TAAA using branched or fenestrated endografts. Data were subjected to a meta-analysis using a random-effects model. The outcomes of interest included early mortality, spinal cord injury, renal failure requiring dialysis, stroke, and hospital length of stay.

RESULTS

Eight comparative studies met inclusion criteria. There were two retrospective propensity-matched studies, two unadjusted single-center retrospective studies, and four unadjusted national population-based studies. Mortality in the matched studies was equivalent in both groups. Pooled analysis of all unmatched observational studies revealed a survival benefit for endovascular over open repair (relative risk [RR], 0.63; 95% confidence interval [CI],0.45-0.87); P < .01, I² = 47%). Endovascular repair was also associated with lower incidence of spinal cord injury (RR, 0.65; 95% CI, 0.42-1.01; P = .05; I² = 28%). For unmatched studies, pooled RR of renal failure requiring dialysis significantly favored endovascular repair (RR, 0.44; 95% CI, 0.23-0.85; P = .01; I² = 0%), although in the adjusted cohort, risk of dialysis was not different (RR, 1.00; 95% CI, 0.06-15.65; P = 1.00). Postoperative stroke rate was reported in three unadjusted studies and was not different between groups (RR, 0.81; 95% CI, 0.28-2.40; P = .71; I² = 77%). Hospital length of stay was reported in four studies and was shorter in the endovascular group (mean difference, -4.4 days; 95% CI, -6.6 to -1.7; P < .01; I² = 73%).

CONCLUSIONS

There are few reports comparing endovascular vs open repair of TAAAs. Short-term outcomes may be improved in patients undergoing endovascular treatment of TAAA on the basis of a limited number of studies with high risk of bias. These findings highlight the need for larger comparative studies with standardization of reporting.

Will This Patient Be Difficult to Intubate?: The Rational Clinical Examination Systematic Review

IMPORTANCE

Recognizing patients in whom endotracheal intubation is likely to be difficult can help alert physicians to the need for assistance from a clinician with airway training and having advanced airway management equipment available.

OBJECTIVE

To identify risk factors and physical findings that predict difficult intubation.

DATA SOURCES

The databases of MEDLINE and EMBASE were searched from 1946 to June 2018 and from 1947 to June 2018, respectively, and the reference lists from the retrieved articles and previous reviews were searched for additional studies.

STUDY SELECTION

Sixty-two studies with high (level 1-3) methodological quality that evaluated the accuracy of clinical findings for identifying difficult intubation were reviewed.

DATA EXTRACTION AND SYNTHESIS

Two authors independently abstracted data. Bivariate random-effects meta-analyses were used to calculate summary positive likelihood ratios across studies or univariate random-effects models when bivariate models failed to converge.

RESULTS

Among the 62 high-quality studies involving 33 559 patients, 10% (95% CI, 8.2%-12%) of patients were difficult to intubate. The physical examination findings that best predicted a difficult intubation included a grade of class 3 on the upper lip bite test (lower incisors cannot extend to reach the upper lip; positive likelihood ratio, 14 [95% CI, 8.9-22]; specificity, 0.96 [95% CI, 0.93-0.97]), shorter hyomental distance (range of <3-5.5 cm; positive likelihood ratio, 6.4 [95% CI, 4.1-10]; specificity, 0.97 [95% CI, 0.94-0.98]), retrognathia (mandible measuring <9 cm from the angle of the jaw to the tip of the chin or subjectively short; positive likelihood ratio, 6.0 [95% CI, 3.1-11]; specificity, 0.98 [95% CI, 0.90-1.0]), and a combination of physical findings based on the Wilson score (positive likelihood ratio, 9.1 [95% CI, 5.1-16]; specificity, 0.95 [95% CI, 0.90-0.98]). The widely used modified Mallampati score (≥3) had a positive likelihood ratio of 4.1 (95% CI, 3.0-5.6; specificity, 0.87 [95% CI, 0.81-0.91]).

CONCLUSIONS AND RELEVANCE

Although several simple clinical findings are useful for predicting a higher likelihood of difficult endotracheal intubation, no clinical finding reliably excludes a difficult intubation. An abnormal upper lip bite test, which is easily assessed by clinicians, raises the probability of difficult intubation from 10% to greater than 60% for the average-risk patient.

Antimicrobial Stewardship Programs in Long-Term Care Settings: A Meta-Analysis and Systematic Review

BACKGROUND

Antimicrobial stewardship programs have been established in hospitals, but less studied in long‐term care facilities (LTCFs), a setting with unique challenges related to patient populations and available resources. This systematic review sought to provide a comprehensive assessment of antimicrobial stewardship interventions implemented in LTCFs, using meta‐analysis to examine their impact on overall antimicrobial use.

METHODS

Electronic searches of MEDLINE, Embase, and CINAHL (1990 to July 2018) identified any antimicrobial stewardship interventions in LTCFs, with no restriction on patient population, study design, or outcomes. Intervention components were categorized using the Cochrane Effective Practice and Organization of Care taxonomy on implementation strategies. Random‐effects meta‐analysis used ratio of means to facilitate pooling of different metrics of antimicrobial use.

RESULTS

Eighteen studies (one randomized controlled trial [RCT], four cluster RCTs, four controlled pre/post studies, and nine uncontrolled pre/post studies) met inclusion, using 13 different antimicrobial stewardship intervention strategies; 15 studies used multifaceted (maximum, seven; median, four) interventions. The three most commonly implemented strategies were educational materials, educational meetings, and guideline implementation. Intervention labor intensity and resource requirements varied considerably among interventions. Meta‐analysis of 11 studies demonstrated that antimicrobial stewardship strategies were associated with a 14% reduction in overall antimicrobial use (95% confidence interval = −8% to −20%; P < .0001), with similar results by study design but high heterogeneity (I² = 86%) for the uncontrolled pre/post study subgroup and no heterogeneity (I² = 0%) for the cluster RCT and controlled pre/post study subgroups. Funnel plot analysis suggested publication bias, with a lack of publication of smaller studies showing increased antibiotic use.

CONCLUSION

Antimicrobial stewardship strategies implemented in long‐term care vary considerably in design and resource intensity, but collectively suggest potential to reduce antimicrobial use in this challenging setting. J Am Geriatr Soc 67:392–399, 2019.

Low-molecular-weight heparin venous thromboprophylaxis in critically ill patients with renal dysfunction: A subgroup analysis of the PROTECT trial

Introduction

There is concern about excessive bleeding when low-molecular-weight heparins (LMWHs) are used for venous thromboembolism (VTE) prophylaxis in renal dysfunction. Our objective was to evaluate whether LMWH VTE prophylaxis was safe and effective in critically ill patients with renal dysfunction by conducting a subgroup analysis of PROTECT, a randomized blinded trial.

Methods

We studied intensive care unit (ICU) patients with pre-ICU dialysis-dependent end-stage renal disease (ESRD; pre-specified subgroup; n = 118), or severe renal dysfunction at ICU admission (defined as ESRD or non-dialysis dependent with creatinine clearance [CrCl] <30 ml/min; post hoc subgroup; n = 590). We compared dalteparin, 5000 IU daily, with unfractionated heparin (UFH), 5000 IU twice daily, and considered outcomes of proximal leg deep vein thrombosis (DVT); pulmonary embolism (PE); any VTE; and major bleeding. Adjusted hazard ratios [HR] were calculated using Cox regression.

Results

In patients with ESRD, there was no significant difference in DVT (8.3% vs. 5.2%, p = 0.76), any VTE (10.0% vs. 6.9%; p = 0.39) or major bleeding (5.0% vs. 8.6%; p = 0.32) between UFH and dalteparin. In patients with severe renal dysfunction, there was no significant difference in any VTE (10.0% vs. 6.4%; p = 0.07) or major bleeding (8.9% vs. 11.0%; p = 0.66) but an increase in DVT with dalteparin (7.6% vs. 3.7%; p = 0.04). Interaction p-values for comparisons of HRs (ESRD versus not) were non-significant.

Conclusions

In critically ill patients with ESRD, or severe renal dysfunction, there was no significant difference in any VTE or major bleeding between UFH and dalteparin. Patients with severe renal dysfunction who received dalteparin had more proximal DVTs than those on UFH; this finding did not hold in patients with ESRD alone.

Surgical Management of Tricuspid Valve Infective Endocarditis: A Systematic Review and Meta-Analysis

BACKGROUND

This meta-analysis compares the early and late outcomes of valve repair versus replacement, the primary surgical strategies for tricuspid valve infective endocarditis (IE).

METHODS

We searched MEDLINE and EMBASE databases until 2016 for studies comparing tricuspid valve repair and replacement.

RESULTS

The main outcomes were mortality, recurrent IE, and need for reoperation. There were 12 unmatched retrospective observational studies with 1,165 patients (median follow-up 3.8 years, interquartile range: 2.1 to 5.0). The most common indications for surgery were septic pulmonary embolism, left-sided IE, right-side heart failure, and persistent bacteremia. Median repair proportion was 59% and replacement was 41% among studies. The primary repair strategies are vegetectomy, De Vega procedure, annuloplasty ring, bicuspidization, and leaflet patch augmentation. Of valve replacements, 83% were bioprosthetic and 17% mechanical prostheses. There were no differences in perioperative mortality between tricuspid valve repair versus replacement (relative risk [RR] 0.62, 95% confidence interval [CI]: 0.26 to 1.46, p = 0.3). Long-term all-cause mortality was not different (RR 0.61, 95% CI: 0.22 to 1.72, p = 0.4). Valve repair was associated with lower recurrent IE (RR 0.17, 95% CI: 0.05 to 0.57, p = 0.004) and need for reoperation (RR 0.26, 95% CI: 0.07 to 0.92, p = 0.04) but a trend toward greater risk of moderate to severe tricuspid regurgitation (RR 4.14, 95% CI: 0.80 to 21.34, p = 0.09). Furthermore, tricuspid valve repair is associated with lower need for permanent pacemaker (RR 0.20, 95% CI: 0.11 to 0.35, p < 0.001).

CONCLUSIONS

Tricuspid valve repair and replacement offer similar long-term survival. Valve repair may offer greater freedom from recurrent IE and reoperation as well as freedom from pacemaker and should be the preferred approach for patients with tricuspid valve IE.

Evidence Supporting Clinical Use of Proportional Assist Ventilation: A Systematic Review and Meta-Analysis of Clinical Trials

BACKGROUND

While proportional assist ventilation (PAV), generates pressure in proportion to effort without a preselected target, proportional assist ventilation plus (PAV+) measures compliance and resistance, calculates work of breathing, and adjusts support to a preset assistance level.

OBJECTIVE

To summarize randomized controlled trials (RCTs) comparing invasive or noninvasive PAV or PAV+ in critically ill patients. Data Sources: We searched multiple databases to April 2017 without language restrictions and conference proceedings from 5 meetings to identify randomized parallel-group and crossover RCTs that compared invasive or noninvasive PAV or PAV+ to another mode in critically ill adults or children and reported at least 1 clinically important outcome.

RESULTS

We identified 14 RCTs (11 parallel group and 3 crossover) assessing PAV (n = 7) and PAV+ (n = 7) involving 931 adult patients. We found no effect of noninvasive PAV (vs noninvasive pressure support [PS]) on intubation (risk ratio 0.92 [0.59 to 1.43], I² = 0%) or invasive PAV (vs invasive PS) on percentage rapid eye movement sleep (mean difference [MD] -2.93% [-14.20 to ±8.34], I² = 43%). Compared to invasive PS, invasive PAV+ showed a nonsignificant increase in weaning time (MD +0.54 [-0.67 to +1.75] hours, I² = 0%), but no effect on hospital mortality, reintubation, or tracheostomy.

CONCLUSIONS

Current evidence does not support the use of invasive or noninvasive PAV or invasive PAV+ in critically ill adults. Amid low to moderate heterogeneity, we identified 3 promising areas for future research including assessing the role of noninvasive PAV as an initial support strategy in patients with acute respiratory failure, invasive PAV on sleep quality during invasive ventilation, and possibly invasive PAV+ for weaning.

Rigid Plate Fixation Versus Wire Cerclage for Sternotomy After Cardiac Surgery: A Meta-Analysis

BACKGROUND

Traditionally, wire cerclage has been used to reapproximate the sternum after sternotomy. Recent evidence suggests that rigid plate fixation for sternal closure may reduce the risk of sternal complications.

METHODS

The Medline and Embase databases were searched from inception to February 2017 for studies that compared rigid plate fixation with wire cerclage for cardiac surgery patients undergoing sternotomy. Random effects meta-analysis compared rates of sternal complications (primary outcome, defined as deep or superficial sternal wound infection, or sternal instability), early mortality, and length of stay (secondary outcomes).

RESULTS

Three randomized controlled trials (n = 427) and five unadjusted observational studies (n = 1,025) met inclusion criteria. There was no significant difference in sternal complications with rigid plate fixation at a median of 6 months' follow-up (incidence rate ratio 0.51, 95% confidence interval [CI]: 0.20 to 1.29, p = 0.15) overall, but a decrease when including only patients at high risk for sternal complications (incidence rate ratio 0.23, 95% CI: 0.06 to 0.89, p = 0.03; two observational studies). Perioperative mortality was reduced favoring rigid plate fixation (relative risk 0.40, 95% CI: 0.28 to 0.97, p = 0.04; four observational studies and one randomized controlled trial). Length of stay was similar overall (mean difference -0.77 days, 95% CI: -1.65 to +0.12, p = 0.09), but significantly reduced with rigid plate fixation in the observational studies (mean difference -1.34 days, 95% CI: -2.05 to -0.63, p = 0.0002).

CONCLUSIONS

This meta-analysis, driven by the results of unmatched observational studies, suggests that rigid plate fixation may lead to reduced sternal complications in patients at high risk for such events, improved perioperative survival, and decreased hospital length of stay. More randomized controlled trials are required to confirm the potential benefits of rigid plate fixation for primary sternotomy closure.

Core cerebrospinal fluid biomarker profile in cerebral amyloid angiopathy: A meta-analysis

OBJECTIVE

To perform a meta-analysis of 4 core CSF biomarkers (β-amyloid [Aβ]42, Aβ40, total tau [t-tau], and phosphorylated tau [p-tau]) to assess which of these are most altered in sporadic cerebral amyloid angiopathy (CAA).

METHODS

We systematically searched PubMed for eligible studies reporting data on CSF biomarkers reflecting amyloid precursor protein metabolism (Aβ42, Aβ40), neurodegeneration (t-tau), and tangle pathology (p-tau) in symptomatic sporadic CAA cohorts vs controls and patients with Alzheimer disease (AD). Biomarker performance was assessed in random-effects meta-analysis based on ratio of mean (RoM) biomarker concentrations: (1) in patients with CAA vs healthy controls and (2) in patients with CAA vs patients with AD. RoM >1 indicates higher biomarker concentration in patients with CAA vs comparison population and RoM <1 indicates higher concentration in comparison groups.

RESULTS

Three studies met inclusion criteria. These comprised 5 CAA patient cohorts (n = 59 patients) vs healthy controls (n = 94 cases) and AD cohorts (n = 158). Three core biomarkers differentiated CAA from controls: CSF Aβ42 (RoM 0.49, 95% confidence interval [CI] 0.38-0.64, p < 0.003), Aβ40 (RoM 0.70, 95% CI 0.63-0.78, p < 0.0001), and t-tau (RoM 1.54, 95% CI 1.15-2.07, p = 0.004); p-tau was marginal (RoM 1.24, 95% CI 0.99-1.54, p = 0.062). Differentiation between CAA and AD was strong for CSF Aβ40 (RoM 0.76, 95% CI 0.69-0.83, p < 0.0001), but not Aβ42 (RoM 1.00; 95% CI 0.81-1.23, p = 0.970). For t-tau and p-tau, average CSF ratios in patients with CAA vs patients with AD were 0.63 (95% CI 0.54-0.74, p < 0.0001) and 0.60 (95% CI 0.50-0.71, p < 0.0001), respectively.

CONCLUSION

Specific CSF patterns of Aβ42, Aβ40, t-tau, and p-tau might serve as molecular biomarkers of CAA, but analyses in larger CAA cohorts are needed.

Evaluation of Metabolic and Synaptic Dysfunction Hypotheses of Alzheimer's Disease (AD): A Meta-Analysis of CSF Markers

BACKGROUND

Alzheimer's disease (AD) is currently incurable and a majority of investigational drugs have failed clinical trials. One explanation for this failure may be the invalidity of hypotheses focusing on amyloid to explain AD pathogenesis. Recently, hypotheses which are centered on synaptic and metabolic dysfunction are increasingly implicated in AD.

OBJECTIVE

Evaluate AD hypotheses by comparing neurotransmitter and metabolite marker concentrations in normal versus AD CSF.

METHODS

Meta-analysis allows for statistical comparison of pooled, existing cerebrospinal fluid (CSF) marker data extracted from multiple publications, to obtain a more reliable estimate of concentrations. This method also provides a unique opportunity to rapidly validate AD hypotheses using the resulting CSF concentration data. Hubmed, Pubmed and Google Scholar were comprehensively searched for published English articles, without date restrictions, for the keywords "AD", "CSF", and "human" plus markers selected for synaptic and metabolic pathways. Synaptic markers were acetylcholine, gamma-aminobutyric acid (GABA), glutamine, and glycine. Metabolic markers were glutathione, glucose, lactate, pyruvate, and 8 other amino acids. Only studies that measured markers in AD and controls (Ctl), provided means, standard errors/deviation, and subject numbers were included. Data were extracted by six authors and reviewed by two others for accuracy. Data were pooled using ratio of means (RoM of AD/Ctl) and random effects meta-analysis using Cochrane Collaboration's Review Manager software.

RESULTS

Of the 435 identified publications, after exclusion and removal of duplicates, 35 articles were included comprising a total of 605 AD patients and 585 controls. The following markers of synaptic and metabolic pathways were significantly changed in AD/controls: acetylcholine (RoM 0.36, 95% CI 0.24-0.53, p<0.00001), GABA (0.74, 0.58-0.94, p<0.01), pyruvate (0.48, 0.24-0.94, p=0.03), glutathione (1.11, 1.01- 1.21, p=0.03), alanine (1.10, 0.98-1.23, p=0.09), and lower levels of significance for lactate (1.2, 1.00-1.47, p=0.05). Of note, CSF glucose and glutamate levels in AD were not significantly different than that of the controls.

CONCLUSION

This study provides proof of concept for the use of meta-analysis validation of AD hypotheses, specifically via robust evidence for the cholinergic hypothesis of AD. Our data disagree with the other synaptic hypotheses of glutamate excitotoxicity and GABAergic resistance to neurodegeneration, given observed unchanged glutamate levels and decreased GABA levels. With regards to metabolic hypotheses, the data supported upregulation of anaerobic glycolysis, pentose phosphate pathway (glutathione), and anaplerosis of the tricarboxylic acid cycle using glutamate. Future applications of meta-analysis indicate the possibility of further in silico evaluation and generation of novel hypotheses in the AD field.