What change in outcomes after cardiac arrest is necessary to change practice? Results of an international survey

Background: Efficient trials of interventions for patients with out-of-hospital cardiac arrest (OHCA) should have adequate but not excess power to detect a difference in outcomes. The minimum clinically important difference (MCID) is the threshold value in outcomes observed in a trial at which providers should choose to adopt a treatment. There has been limited assessment of MCID for outcomes after OHCA. Therefore, we conducted an international survey of individuals interested in cardiac resuscitation to define the MCID for a range of outcomes after OHCA. Methods: A brief survey instrument was developed and modified by consensus. Included were open-ended responses. The survey included an illustrative example of a hypothetical randomized study with distributions of outcomes based on those in a public use datafile from a previous trial. Elicited information included the minimum significant difference required in an outcome to change clinical practice. The population of interest was emergency physicians or other practitioners of acute cardiovascular research. Results: Usable responses were obtained from 160 respondents (50% of surveyed) in 46 countries (79% of surveyed). MCIDs tended to increase as baseline outcomes increased. For a population of patients with 25% survival to discharge and 20% favorable neurologic status at discharge, the MCID were median 5 (interquartile range [IQR] 3, 10) percent for survival to discharge; median 5 (IQR 2, 10) percent for favorable neurologic status at discharge, median 4 (IQR 2, 9) days of ICU-free survival and median 4 (IQR 2, 8) days of hospital-free survival. Conclusion: Reported MCIDs for outcomes after OHCA vary according to the outcome considered as well as the baseline rate of achieving it. MCIDs of ICU-free survival or hospital-free survival may be useful to accelerate the rate of evidence-based change in resuscitation care. (C) 2016 Elsevier Ireland Ltd. All rights reserved.Peer reviewe

What change in outcomes after cardiac arrest is necessary to change practice? Results of an international survey

Background: Efficient trials of interventions for patients with out-of-hospital cardiac arrest (OHCA) should have adequate but not excess power to detect a difference in outcomes. The minimum clinically important difference (MCID) is the threshold value in outcomes observed in a trial at which providers should choose to adopt a treatment. There has been limited assessment of MCID for outcomes after OHCA. Therefore, we conducted an international survey of individuals interested in cardiac resuscitation to define the MCID for a range of outcomes after OHCA. Methods: A brief survey instrument was developed and modified by consensus. Included were open-ended responses. The survey included an illustrative example of a hypothetical randomized study with distributions of outcomes based on those in a public use datafile from a previous trial. Elicited information included the minimum significant difference required in an outcome to change clinical practice. The population of interest was emergency physicians or other practitioners of acute cardiovascular research. Results: Usable responses were obtained from 160 respondents (50% of surveyed) in 46 countries (79% of surveyed). MCIDs tended to increase as baseline outcomes increased. For a population of patients with 25% survival to discharge and 20% favorable neurologic status at discharge, the MCID were median 5 (interquartile range [IQR] 3, 10) percent for survival to discharge; median 5 (IQR 2, 10) percent for favorable neurologic status at discharge, median 4 (IQR 2, 9) days of ICU-free survival and median 4 (IQR 2, 8) days of hospital-free survival. Conclusion: Reported MCIDs for outcomes after OHCA vary according to the outcome considered as well as the baseline rate of achieving it. MCIDs of ICU-free survival or hospital-free survival may be useful to accelerate the rate of evidence-based change in resuscitation care. (C) 2016 Elsevier Ireland Ltd. All rights reserved

A Randomized Clinical Trial Testing the Anti-Inflammatory Effects of Preemptive Inhaled Nitric Oxide in Human Liver Transplantation

<div><p>Decreases in endothelial nitric oxide synthase derived nitric oxide (NO) production during liver transplantation promotes injury. We hypothesized that preemptive inhaled NO (iNO) would improve allograft function (primary) and reduce complications post-transplantation (secondary). Patients at two university centers (Center A and B) were randomized to receive placebo (n = 20/center) or iNO (80 ppm, n = 20/center) during the operative phase of liver transplantation. Data were analyzed at set intervals for up to 9-months post-transplantation and compared between groups. Patient characteristics and outcomes were examined with the Mann-Whitney U test, Student t-test, logistic regression, repeated measures ANOVA, and Cox proportional hazards models. Combined and site stratified analyses were performed. MELD scores were significantly higher at Center B (22.5 vs. 19.5, p<0.0001), surgical times were greater at Center B (7.7 vs. 4.5 hrs, p<0.001) and warm ischemia times were greater at Center B (95.4 vs. 69.7 min, p<0.0001). No adverse metabolic or hematologic effects from iNO occurred. iNO enhanced allograft function indexed by liver function tests (Center B, p<0.05; and p<0.03 for ALT with center data combined) and reduced complications at 9-months (Center A and B, p = 0.0062, OR = 0.15, 95% CI (0.04, 0.59)). ICU (p = 0.47) and hospital length of stay (p = 0.49) were not decreased. iNO increased concentrations of nitrate (p<0.001), nitrite (p<0.001) and nitrosylhemoglobin (p<0.001), with nitrite being postulated as a protective mechanism. Mean costs of iNO were $1,020 per transplant. iNO was safe and improved allograft function at one center and trended toward improving allograft function at the other. ClinicalTrials.gov with registry number 00582010 and the following URL:<a href="http://clinicaltrials.gov/show/NCT00582010" target="_blank">http://clinicaltrials.gov/show/NCT00582010</a>.</p></div

iNO therapy did not affect hospital or ICU length of stay.

<p>Kaplan-Meier plots shown and with P-values from Cox proportional hazards models adjusting for MELD, cold ischemic time, weight, BMI, warm ischemic time or donor age within each center. Placebo = ○, iNO = ▪.</p

Effects of iNO on reperfusion induced injury and PMN accumulation.

<p>Liver biopsy samples were collected pre- (LB1, □) and 1 hr post dual reperfusion (LB2, ▪) and assessed for injury by histopathologic evaluation (Panel A, B) and infiltration of PMN (panel C, D). Data from both UAB and UW cohorts are combined (n = 38). P-values indicated on graph are by paired t-test for panels A and C or by * unpaired t-test (panels B and D).</p

Changes in metHb and nitrogen dioxide (NO₂) as a function of blood draw (BD) in placebo (○) or iNO (▪) groups.

<p>Data are mean ± SEM (n = 20 for each group, except UAB placebo where n = 19 and UW iNO where n = 17–20. *P<0.0001 by 2-way ANOVA with Bonferroni multiple comparisons post-test.</p

Individual responses to iNO on TUNEL staining pre- and post-reperfusion.

<p>Panel A and B show changes in TUNEL positive nuclei in hepatic central vein area and panels C and D in the hepatic triad area for Center A (panel A and B) and Center B (panel C and D) cohorts. Indicated P-values determined by Wilcoxon rank-sum (n = 18–20).</p

iNO effects on plasma ceruloplasmin activity.

<p>Plasma ceruloplasmin activity was measured in venous samples collected during surgery from patients administered placebo (□) or iNO (•). Data show mean ± SEM (n = 19–20).</p

Patient demographic differences between study sites.

<p>Panels A–E show respectively patient weight, MELD scores, surgery, warm ischemic times and donor risk index (DRI). Each data point represents individual patient (n = 37–40 for Center A, and n = 40 for Center B). Indicated P-values are from unpaired t-test (panel A and E) or Mann-Whitney U test (panels B–D).</p

Patient and Surgery Demographics for Center B Cohort.

<p>Values show median (range). P-values calculated from unpaired t-test for placebo vs. iNO.</p