Platelet aggregation during targeted temperature management after out-of-hospital cardiac arrest: A randomised clinical trial

Some studies conclude that mild hypothermia causes platelet dysfunction leading to an increased bleeding risk, whereas others state that platelet aggregation is enhanced during mild hypothermia. Therefore, the aim of this study was to clarify whether standard or prolonged duration of targeted temperature management affected platelet aggregation. We randomised 82 comatose patients resuscitated after out-of-hospital cardiac arrest to either 24 hours (standard group) or 48 hours (prolonged group) of targeted temperature management at 33±1°C. Blood samples were collected 22 hours, 46 hours and 70 hours after reaching target temperature. Platelet aggregation was assessed by impedance aggregometry employing a Multiplate®Analyser, using the COLtest®, TRAPtest®, ADPtest® and ASPItest® as agonists, and with the results reported as area under the curve (AUC, AU*min). The platelet aggregation was below the normal range in all blood samples. No differences were observed between the standard group and the prolonged group in either of the blood samples (all p ≥ 0.11), except for a 24% decreased aggregation (95% confidence interval (CI) (10%;37%), p = 0.002) when using the COLtest® in the 46-hour sample. Comparing the 22-hour sample with the 46-hour sample in the prolonged group separately, we found no differences when employing the COLtest®, the ASPItest® or the ADPtest® in patients without the use of adenosine diphosphate receptor inhibitors (all p values ≥0.21), but aggregation induced by the TRAPtest® decreased by 14% (95% CI −8%;−20%), p < 0.001). We concluded that the platelet aggregation post cardiac arrest was below the normal range independent of the core temperature. Moreover, no substantial difference was found in platelet aggregation between standard and prolonged targeted temperature management

Targeted Temperature Management for 48 vs 24 Hours and Neurologic Outcome After Out-of-Hospital Cardiac Arrest:A Randomized Clinical Trial

IMPORTANCE: International resuscitation guidelines recommend targeted temperature management (TTM) at 33°C to 36°C in unconscious patients with out-of-hospital cardiac arrest for at least 24 hours, but the optimal duration of TTM is uncertain. OBJECTIVE: To determine whether TTM at 33°C for 48 hours results in better neurologic outcomes compared with currently recommended, standard, 24-hour TTM. DESIGN, SETTING, AND PARTICIPANTS: This was an international, investigator-initiated, blinded-outcome-assessor, parallel, pragmatic, multicenter, randomized clinical superiority trial in 10 intensive care units (ICUs) at 10 university hospitals in 6 European countries. Three hundred fifty-five adult, unconscious patients with out-of-hospital cardiac arrest were enrolled from February 16, 2013, to June 1, 2016, with final follow-up on December 27, 2016. INTERVENTIONS: Patients were randomized to TTM (33 ± 1°C) for 48 hours (n = 176) or 24 hours (n = 179), followed by gradual rewarming of 0.5°C per hour until reaching 37°C. MAIN OUTCOMES AND MEASURES: The primary outcome was 6-month neurologic outcome, with a Cerebral Performance Categories (CPC) score of 1 or 2 used to define favorable outcome. Secondary outcomes included 6-month mortality, including time to death, the occurrence of adverse events, and intensive care unit resource use. RESULTS: In 355 patients who were randomized (mean age, 60 years; 295 [83%] men), 351 (99%) completed the trial. More patients in the 48-hour group had a favorable outcome, but this was not statistically significant. Six-month mortality was not different between the groups. Adverse events were more common in the 48-hour group than in the 24-hour group. There was no significant difference in the time to mortality (hazard ratio, 0.79; 95% CI, 0.54-1.15; P = .22). The median length of ICU stay (151 vs 117 hours; P < .001), but not hospital stay (11 vs 12 days; P = .50), was longer in the 48-hour group than in the 24-hour group. (Table Presented) CONCLUSIONS AND RELEVANCE: In unconscious survivors from out-of-hospital cardiac arrest admitted to the ICU, targeted temperature management at 33°C for 48 hours did not significantly improve 6-month neurologic outcome compared with targeted temperature management at 33°C for 24 hours. However, the study may have had limited power to detect clinically important differences, and further research may be warranted. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01689077.SCOPUS: ar.jinfo:eu-repo/semantics/publishe