Citations

BACKGROUND: Patients who develop ARDS from medical or traumatic causes typically present after the inciting event has already occurred. Postoperative ARDS is unique in that the inciting insult potentially responsible for ARDS is known ahead of time, which provides an opportunity to study the early pathophysiology of ARDS. The objective of this study was to better understand the early pathophysiology of postoperative ARDS through a temporal analysis of key biomarkers of interest. METHODS: We performed a case-control study of adults undergoing elective thoracic, aortic vascular, or cardiac surgery, which placed them at increased risk of developing postoperative ARDS. Biomarkers were measured at baseline, 2 h, and 6 h after the key intraoperative event believed to be responsible for ARDS. RESULTS: Of the 467 subjects enrolled, 26 developed ARDS and were matched to non-ARDS controls 1:2 based on age, sex, surgical procedure, and surgical lung injury prediction score. Patients with ARDS were more likely to have lower preoperative albumin ( P = .029), longer surgery ( P = .007), larger amounts of intraoperative fluid ( P = .036), and higher intraoperative peak inspiratory pressures ( P = .006). Baseline plasminogen activator inhibitor-1 levels were higher in the ARDS group ( P = .03). Changes in postoperative biomarker levels from baseline were greater in the ARDS group for interleukin-8 (baseline to 6 h, P = .02) and surfactant protein-D (baseline to 2 h, P = .009). CONCLUSIONS: Our study supported the hypothesis that dysregulated coagulation, inflammation, and epithelial injury are pathophysiologic features of early postoperative ARDS. Interleukin-8, plasminogen activator-1, and surfactant protein-D may help predict development of postoperative ARDS.

Abstract Rationale Acute respiratory distress syndrome (ARDS) is a devastating illness with limited therapeutic options. A better understanding of early biochemical and immunological events in ARDS could inform the development of new preventive and treatment strategies. Objectives To determine select peripheral blood lipid mediator and leukocyte responses in patients at risk for ARDS. Methods Patients at risk for ARDS were randomized as part of a multicenter, double-blind clinical trial of aspirin versus placebo (the LIPS-A [Lung Injury Prevention Study with Aspirin] trial; NCT01504867). Plasma thromboxane B2 (TXB2), aspirin-triggered lipoxin A4 (15-epi-LXA4, ATL), and peripheral blood leukocyte number and activation were determined on enrollment and after treatment with either aspirin or placebo. Measurements and Main Results Thirty-three of 367 subjects (9.0%) developed ARDS after randomization. Baseline ATL levels, total monocyte counts, intermediate monocyte counts, and monocyte–platelet aggregates were associated with the development of ARDS. Peripheral blood neutrophil count and monocyte–platelet aggregates significantly decreased over time. Of note, nine subjects developed ARDS after randomization yet before study drug initiation, including seven subjects assigned to aspirin treatment. Subjects without ARDS at the time of first dose demonstrated a lower incidence of ARDS with aspirin treatment. Compared with placebo, aspirin significantly decreased TXB2 and increased the ATL/TXB2 ratio. Conclusions Biomarkers of intravascular monocyte activation in at-risk patients were associated with development of ARDS. The potential clinical benefit of early aspirin for prevention of ARDS remains uncertain. Together, results of the biochemical and immunological analyses provide a window into the early pathogenesis of human ARDS and represent potential vascular biomarkers of ARDS risk. Clinical trial registered with www.clinicaltrials.gov (NCT01504867).

Objectives: Midodrine is an oral alpha-agonist approved for orthostatic hypotension. The use of midodrine as a vasopressor sparing agent has steadily increased in the ICU despite limited evidence for its safety in that setting. We describe the trends in use and reported side effects and complications of midodrine in multidisciplinary ICUs of a tertiary care institution. Design: Single-center retrospective case series. Setting: Medical and surgical ICU patients from January 2011 to October 2016 at Mayo Clinic, Rochester. Patients: Adult patients admitted to any ICU who received midodrine for hypotension were eligible. Interventions: None. Measurements and Main Results: We reviewed the mean arterial pressures and cumulative vasopressor dose before and after midodrine administration and assessed for reported complications. During the study period, a total of 1,119 patients were initiated on midodrine, 56% in surgical ICUs, 42% in medical ICUs, and 2% in a mixed medical and surgical neurology ICU. There was a significant decrease in the number of patients on vasopressors 24 hours after initiation of midodrine (663 to 344; p < 0.001); among the patients that remained on vasopressors, there was a significant decrease in the median cumulative vasopressor dose (p = 0.002). There was a significant increase in median mean arterial pressure 24 hours after initiation of midodrine among patients who were not on vasopressors (65–68; p < 0.01). Asymptomatic bradycardia (heart rate < 50 beats/min) was the most common side effect (n = 172 patients, median 39 beats/min). Two patients developed bowel ischemia after initiation of midodrine that prompted discontinuation of midodrine in one case. Evaluating trends of utilization, the off-label use of midodrine has increased steadily over the years across ICUs. Conclusions: Our results suggest that midodrine is being increasingly used as an adjunct to increase mean arterial pressure and facilitate weaning of vasopressors in the ICU. Prospective trials are required to further establish the appropriate timing, efficacy, safety, and cost-effectiveness of midodrine use in ICU patients.

Background Optimal methods of mortality risk stratification in patients in the cardiac intensive care unit ( CICU ) remain uncertain. We evaluated the ability of the Sequential Organ Failure Assessment ( SOFA ) score to predict mortality in a large cohort of unselected patients in the CICU. Methods and Results Adult patients admitted to the CICU from January 1, 2007, to December 31, 2015, at a single tertiary care hospital were retrospectively reviewed. SOFA scores were calculated daily, and Acute Physiology and Chronic Health Evaluation ( APACHE )‐ III and APACHE ‐ IV scores were calculated on CICU day 1. Discrimination of hospital mortality was assessed using area under the receiver‐operator characteristic curve values. We included 9961 patients, with a mean age of 67.5±15.2 years; all‐cause hospital mortality was 9.0%. Day 1 SOFA score predicted hospital mortality, with an area under the receiver‐operator characteristic curve value of 0.83; area under the receiver‐operator characteristic curve values were similar for the APACHE ‐ III score, and APACHE ‐ IV predicted mortality ( P >0.05). Mean and maximum SOFA scores over multiple CICU days had greater discrimination for hospital mortality ( P <0.01). Patients with an increasing SOFA score from day 1 and day 2 had higher mortality. Patients with day 1 SOFA score <2 were at low risk of mortality. Increasing tertiles of day 1 SOFA score predicted higher long‐term mortality ( P <0.001 by log‐rank test). Conclusions The day 1 SOFA score has good discrimination for short‐term mortality in unselected patients in the CICU, which is comparable to APACHE ‐ III and APACHE ‐ IV . Advantages of the SOFA score over APACHE include simplicity, improved discrimination using serial scores, and prediction of long‐term mortality.

Objectives: To assess the effectiveness of noninvasive ventilation in patients with acute respiratory failure and do-not-intubate or comfort-measures-only orders. Data Sources: MEDLINE, EMBASE, CINAHL, Scopus, and Web of Science from inception to January 1, 2017. Study Selection: Studies of all design types that enrolled patients in the ICU or hospital ward who received noninvasive ventilation and had preset do-not-intubate or comfort-measures-only orders. Data Extraction: Data abstraction followed Meta-analysis of Observational Studies in Epidemiology guidelines. Data quality was assessed using a modified Newcastle-Ottawa Scale. Data Synthesis: Twenty-seven studies evaluating 2,020 patients with do-not-intubate orders and three studies evaluating 200 patients with comfort-measures-only orders were included. In patients with do-not-intubate orders, the pooled survival was 56% (95% CI, 49–64%) at hospital discharge and 32% (95% CI, 21–45%) at 1 year. Hospital survival was 68% for chronic obstructive pulmonary disease, 68% for pulmonary edema, 41% for pneumonia, and 37% for patients with malignancy. Survival was comparable for patients treated in a hospital ward versus an ICU. Quality of life of survivors was not reduced compared with baseline, although few studies evaluated this. No studies evaluated quality of dying in nonsurvivors. In patients with comfort-measures-only orders, a single study showed that noninvasive ventilation was associated with mild reductions in dyspnea and opioid requirements. Conclusions: A large proportion of patients with do-not-intubate orders who received noninvasive ventilation survived to hospital discharge and at 1 year, with limited data showing no decrease in quality of life in survivors. Provision of noninvasive ventilation in a well-equipped hospital ward may be a viable alternative to the ICU for selected patients. Crucial questions regarding quality of life in survivors, quality of death in nonsurvivors, and the impact of noninvasive ventilation in patients with comfort-measures-only orders remain largely unanswered.

Objective: Predictors of long-term functional impairment in acute respiratory failure of all causes are poorly understood. Our objective was to assess the frequency and predictors of long-term functional impairment or death after invasive mechanical ventilation for acute respiratory failure of all causes. Design: Population-based, observational cohort study. Setting: Eight adult ICUs of a single center. Patients: All adult patients from Olmsted County, Minnesota, without baseline functional impairment who received mechanical ventilation in ICUs for acute respiratory failure of all causes from 2005 through 2009. Interventions: None. Measurements and Main Results: In total, 743 patients without baseline functional impairment received mechanical ventilation in the ICU. At 1- and 5-year follow-up, the rates of survival with return to baseline functional ability were 61% (366/597) and 53% (356/669). Among 71 patients with new functional impairment at 1 year, 55% (39/71) had recovered and were alive without functional impairment at 5 years. Factors predictive of new functional impairment or death at 1 year were age, comorbidities, discharge to other than home, mechanical ventilation of 7 days or longer, and stroke. Of factors known at the time of intubation, the following are predictive of new functional impairment or death: age, comorbidities, nonsurgical condition, Acute Physiology and Chronic Health Evaluation III score, stroke, and sepsis. Post hoc sensitivity analyses revealed no significant change in predictor variables in patient populations when stroke was excluded or who received more than 48 hours of mechanical ventilation. Conclusions: At 1- and 5-year follow-up, many patients who received mechanical ventilation for acute respiratory failure from all causes are no longer alive or have new moderate-to-severe functional impairment. Functional recovery between year 1 and year 5 is possible and common. Sepsis, stroke, illness severity, age, and comorbidities predict long-term functional outcome at intubation.

Abstract Rationale By minimizing tidal lung strain and maintaining alveolar recruitment, high-frequency oscillatory ventilation (HFOV) may protect against ventilator-induced lung injury. Objectives To summarize the current evidence in support of the use of HFOV in adult patients with acute respiratory distress syndrome. Methods We conducted a systematic review and meta-analysis of randomized trials comparing mortality rates with the use of HFOV versus conventional mechanical ventilation for adult patients with acute respiratory distress syndrome. Eligible trials were identified from previously published systematic reviews and an updated literature search. Data on 28-day mortality, oxygenation, adverse events, and use of rescue therapies were collected; effects were pooled using random effects models weighted by inverse variance. Strength of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation methodology. Results Six trials were eligible for inclusion (total n = 1,715 patients). Four trials mandated lung-protective ventilation in the control group and one trial applied a higher positive end-expiratory pressure (PEEP) ventilation strategy in the control group. None of the trials were judged to be at high risk of bias, though all were unblinded. In trials that did not systematically employ any cointerventions with HFOV and that targeted low tidal volumes in the patients randomized to conventional ventilation (primary analysis), HFOV had no significant effect on mortality (three trials; risk ratio [RR], 1.14; 95% confidence interval [CI], 0.88 to 1.48; evidence grade = high). Pooled analysis of all six trials also did not suggest a significant mortality reduction (RR, 0.94; 95% CI, 0.71 to 1.24; evidence grade = low). The single trial that employed a conventional ventilation strategy with both lower tidal volumes and higher PEEP as control reported higher mortality in patients receiving HFOV (RR, 1.41; 95% CI, 1.12 to 1.79). HFOV was not associated with improved oxygenation after 24 hours (five trials; mean increase of 10 mm Hg; 95% CI, −16 to 37 mm Hg). Rates of barotrauma were not different between HFOV and conventional ventilation, although significant benefit or harm could not be excluded (RR, 1.15; 95% CI, 0.61 to 2.17). Conclusions Published randomized trials suggest that HFOV is not associated with a mortality benefit, and may even be harmful in comparison to ventilation with low tidal volumes and higher levels of PEEP.

Abstract Rationale In patients with acute respiratory distress syndrome (ARDS), lung recruitment maneuvers (LRMs) may prevent ventilator-induced lung injury and improve survival. Objectives To summarize the current evidence in support of the use of LRMs in adult patients with ARDS and to inform the recently published American Thoracic Society/European Society of Intensive Care Medicine/Society of Critical Care Medicine clinical practice guideline on mechanical ventilation in ARDS. Methods We conducted a systematic review and meta-analysis of randomized trials comparing mechanical ventilation strategies with and without LRMs. Eligible trials were identified from among previously published systematic reviews and an updated literature search. Data on 28-day mortality, oxygenation, adverse events, and use of rescue therapy were collected, and results were pooled using random effects models weighted by inverse variance. Strength of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation methodology. Results We screened 430 citations and previous systematic reviews and found six trials eligible for inclusion (n = 1,423 patients in total). The type of LRM varied widely between trials, and five of the trials involved a cointervention with a higher positive end-expiratory pressure (PEEP) ventilation strategy. Risk of bias was deemed high in one trial. In the primary analysis, the only trial without a cointervention showed that LRMs were associated with reduced mortality (one trial; risk ratio [RR], 0.62; 95% confidence interval [CI], 0.39–0.98; evidence grade = low). Meta-analysis of all six trials also suggested a significant mortality reduction (six trials; RR, 0.81; 95% CI, 0.69–0.95; evidence grade = moderate), and the use of a higher PEEP cointervention did not significantly modify the mortality effect (P = 0.27 for heterogeneity). LRMs were also associated with improved oxygenation after 24 hours (six trials; mean increase, 52 mm Hg; 95% CI, 23–81 mm Hg) and less frequent requirement for rescue therapy (three trials; RR, 0.65; 95% CI, 0.45–0.94). LRMs were not associated with an increased rate of barotrauma (four trials; RR, 0.84; 95% CI, 0.46–1.55). The rate of hemodynamic compromise was not significantly increased with LRMs (three trials; RR, 1.30; 95% CI, 0.92–1.78). Conclusions Randomized trials suggest that LRMs in combination with a higher PEEP ventilation strategy reduce mortality, but confidence in this finding is limited. Further trials are required to confirm benefit from LRMs in adults with ARDS.