Factors associated with circulatory death after out-of-hospital cardiac arrest: a population-based cluster analysis

Metabolic effects of high-dose glucocorticoid following out-of-hospital cardiac arrest

BACKGROUND AND AIM

Patients resuscitated after out-of-hospital cardiac arrest (OHCA) face high morbidity and mortality rates, primarily due to ischemia-reperfusion injury, a complex metabolic disorder that triggers a significant systemic inflammatory response. Glucocorticoids mitigate inflammation but also impact the cells beyond the immune response. This study aims to identify glucocorticoid effects on plasma metabolites.

METHODS

This explorative sub-study is part of a two-center, blinded, randomized controlled trial (NCT04624776) examining the effects of high-dose glucocorticoid on comatose patients resuscitated from OHCA of presumed cardiac origin. Following resuscitation, patients received 250 mg of methylprednisolone or a placebo in the prehospital setting. Blood samples were collected upon hospital admission and 48 h later. Sixty metabolites were quantified in the plasma using mass spectrometry and compared between groups.

RESULTS

In the modified intention-to-treat population, 68 patients received methylprednisolone, and 69 received placebo [median age was 66 years (IQR: 56-74) and 83% were men]. Blood samples were available for 130 patients, 121 (88%) at admission and 117 patients (94% of patients alive) after 48 h. Although a nominal difference was observed at admission, no significant metabolic effects were found after correcting for multiple testing. After 48 h, the placebo group had 83.4% (95% CI 16.9-187.6%) higher prostaglandin E2 and higher levels of linolenic acid and arachidonic acid. The methylprednisolone group had higher levels of tryptophan (47.6%; 95% CI 27.9-70.2%), arginine, and propionylcarnitine (C3).

CONCLUSIONS

In this exploratory study, early administration of 250 mg of methylprednisolone after resuscitation appeared to drive sustained metabolic effects over 48 h. Specifically, methylprednisolone led to reductions in ω-6 fatty acids and increases in several amino acids, with a notable rise in tryptophan.

Fluid balance and outcome in cardiac arrest patients admitted to intensive care unit

BACKGROUND

Although shock following cardiac arrest is common and contributes significantly to mortality, the influence of the modalities used to manage the hemodynamic situation, particularly with regard to fluid balance, remains unclear. We evaluated the association between positive fluid balance and outcome after out-of-hospital cardiac arrest (OHCA).

METHODS

We conducted a multicenter study from August 2020 to June 2022, which consecutively enrolled adult OHCA patients in 17 intensive care units. The primary endpoint was 90-day survival. Multivariate Cox analysis, propensity score matching and landmark analysis were performed, along with several sensitivity analyses.

RESULTS

Of the 816 patients included in our study, 74% had a positive fluid balance, and 291 of 816 patients (36%) were alive at 90-day. A positive fluid balance was associated with mortality after adjusted multivariate analysis (HR = 1.8 [1.3 - 2.3], p < 0.001), after propensity score matching (n = 193 matched patient pairs, HR = 1.6 [1.1 - 2.1], p = 0.005) and after landmark analysis. We reported a dose-dependent association between fluid balance and mortality. Patients with a positive fluid balance were more likely to need renal replacement therapy (10% vs. 2%, p = 0.001) and had a lower minimum PaO2/FiO2 ratio in the first seven days (158 vs. 180, p < 0.001).

CONCLUSIONS

After cardiac arrest, a positive fluid balance is consistently associated with a worse outcome. Pending further data, a restrictive fluid therapy strategy may be beneficial in post-OHCA patients.

TRIAL REGISTRATION

ClinicalTrial.gov cohort AfterROSC-1 NCT04167891 registered November 13th, 2019, ethics committees 2019-A01378-49 and CPP-SMIV 190901.

Optimizing brain protection after cardiac arrest: advanced strategies and best practices

Cardiac arrest (CA) is associated with high incidence and mortality rates. Among patients who survive the acute phase, brain injury stands out as a primary cause of death or disability. Effective intensive care management, including targeted temperature management, seizure treatment and maintenance of normal physiological parameters, plays a crucial role in improving survival and neurological outcomes. Current guidelines advocate for neuroprotective strategies to mitigate secondary brain injury following CA, although certain treatments remain subjects of debate. Clinical examination and neuroimaging studies, both invasive and non-invasive neuromonitoring methods and serum biomarkers are valuable tools for predicting outcomes in comatose resuscitated patients. Neuromonitoring, in particular, provides vital insights for identifying complications, personalizing treatment approaches and forecasting prognosis in patients with brain injury post-CA. In this review, we offer an overview of advanced strategies and best practices aimed at optimizing brain protection after CA.

Unsupervised Clustering in Neurocritical Care: A Systematic Review

Managing patients with acute brain injury in the neurocritical care (NCC) unit has become increasingly complex because of technological advances and increasing information derived from multiple data sources. Diverse data streams necessitate innovative approaches for clinicians to understand interactions between recorded variables. Unsupervised clustering integrates different data streams and could be supportive. Here, we provide a systematic review on the use of unsupervised clustering using NCC data. The primary objective was to provide an overview of clustering applications in NCC studies. As a secondary objective, we discuss considerations for future NCC studies. Databases (Medline, Scopus, Web of Science) were searched for unsupervised clustering in acute brain injury studies including traumatic brain injury (TBI), subarachnoid hemorrhage, intracerebral hemorrhage, acute ischemic stroke, and hypoxic-ischemic brain injury published until  March 13th 2024. We performed the systematic review in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. We identified 18 studies that used unsupervised clustering in NCC. Predominantly, studies focused on patients with TBI (12 of 18 studies). Multiple research questions used a variety of resource data, including demographics,  clinical- and monitoring data, of which intracranial pressure was most often included (8 of 18 studies). Studies also covered various clustering methods, both traditional methods (e.g., k-means) and advanced methods, which are able to retain the temporal aspect. Finally, unsupervised clustering identified novel phenotypes for clinical outcomes in 9 of 12 studies. Unsupervised clustering can be used to phenotype NCC patients, especially patients with TBI, in diverse disease stages and identify clusters that may be used for prognostication. Despite the need for validation studies, this methodology could help to improve outcome prediction models, diagnostics, and understanding of pathophysiology.Registration number: PROSPERO: CRD4202347097676.

Cumulative dose of epinephrine and mode of death after non-shockable out-of-hospital cardiac arrest: a registry-based study

BACKGROUND

Epinephrine increases the chances of return of spontaneous circulation (ROSC) in out-of-hospital cardiac arrest (OHCA), especially when the initial rhythm is non-shockable. However, this drug could also worsen the post-resuscitation syndrome (PRS). We assessed the association between epinephrine use during cardiopulmonary resuscitation (CPR) and subsequent intensive care unit (ICU) mortality in patients with ROSC after non-shockable OHCA.

METHODS

We used data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (capturing OHCA data located in the Greater Paris area, France) between May 2011 and December 2021. All adults with ROSC after medical, cardiac and non-cardiac causes, non-shockable OHCA admitted to an ICU were included. The mode of death in the ICU was categorized as cardiocirculatory, neurological, or other.

RESULTS

Of the 2,792 patients analyzed, there were 242 (8.7%) survivors at hospital discharge, 1,004 (35.9%) deaths from cardiocirculatory causes, 1,233 (44.2%) deaths from neurological causes, and 313 (11.2%) deaths from other etiologies. The cardiocirculatory death group received more epinephrine (4.6 ± 3.8 mg versus 1.7 ± 2.8 mg, 3.2 ± 2.6 mg, and 3.5 ± 3.6 mg for survivors, neurological deaths, and other deaths, respectively; p < 0.001). The proportion of cardiocirculatory death increased linearly (R2 = 0.92, p < 0.001) with cumulative epinephrine doses during CPR (17.7% in subjects who did not receive epinephrine and 62.5% in those who received > 10 mg). In multivariable analysis, a cumulative dose of epinephrine was strongly associated with cardiocirculatory death (adjusted odds ratio of 3.45, 95% CI [2.01-5.92] for 1 mg of epinephrine; 12.28, 95% CI [7.52-20.06] for 2-5 mg; and 23.71, 95% CI [11.02-50.97] for > 5 mg; reference 0 mg; population reference: alive at hospital discharge), even after adjustment on duration of resuscitation. The other modes of death (neurological and other causes) were also associated with epinephrine use, but to a lesser extent.

CONCLUSIONS

In non-shockable OHCA with ROSC, the dose of epinephrine used during CPR is strongly associated with early cardiocirculatory death. Further clinical studies aimed at limiting the dose of epinephrine during CPR seem warranted. Moreover, strategies for the prevention and management of PRS should take this dose of epinephrine into consideration for future trials.