Apnea is one of the three cardinal findings in brain death (BD). Apnea testing (AT) is physiologically and practically complex. We sought to review described modifications of AT, safety and complication rates, monitoring techniques, performance of AT on extracorporeal membrane oxygenation (ECMO), and other relevant considerations regarding AT. We conducted a systematic scoping review to answer these questions by searching the literature on AT in English language available in PubMed or EMBASE since 1980. Pediatric or animal studies were excluded. A total of 87 articles matched our inclusion criteria and were qualitatively synthesized in this review. A large body of the literature on AT since its inception addresses a variety of modifications, monitoring techniques, complication rates, ways to perform AT on ECMO, and other considerations such as variability in protocols, lack of uniform awareness, and legal considerations. Only some modifications are widely used, especially methods to maintain oxygenation, and most are not standardized or endorsed by brain death guidelines. Future updates to AT protocols and strive for unification of such protocols are desirable.

Purpose. A 66-year-old man who presented with coma was found to have isolated severe hyperammonemia and diagnosed with a late-onset urea-cycle disorder. He was treated successfully and had full recovery.Methods. We report a novel case of noncirrhotic hyperammonemia and review the literature on this topic. Selected literature for review included English-language articles concerning hyperammonemia using the search terms “hyperammonemic encephalopathy”, “non-cirrhotic encephalopathy”, “hepatic encephalopathy”, “urea-cycle disorders”, “ornithine transcarbamylase (OTC) deficiency”, and “fulminant hepatic failure”.Results. A unique case of isolated hyperammonemia diagnosed as late-onset OTC deficiency is presented. Existing evidence about hyperammonemia is organized to address pathophysiology, clinical presentation, diagnosis, and treatment. The case report is discussed in context of the reviewed literature.Conclusion. Late-onset OTC deficiency presenting with severe hyperammonemic encephalopathy and extensive imaging correlate can be fully reversible if recognized promptly and treated aggressively.

Disorders of consciousness (DoC) represent a spectrum of clinical conditions, including coma, unresponsive wakefulness syndrome, and the minimally conscious state, which may result from structural and non-structural brain injuries due to trauma, stroke, anoxia, infections of the brain, and other causes. Clinical management of patients with DoC is especially challenging in the critical care environment, where the level of consciousness, a key factor in determining the trajectory of recovery, may be obscured by sedation, analgesia, and other confounders. The 2025 International Symposium on Intensive Care and Emergency Medicine hosted a Roundtable of 18 expert clinicians and researchers to synthesise and discuss the latest evidence on acute DoC epidemiology, diagnosis, treatment, and prognosis. Here, we summarise the output of the Roundtable in the format of a roadmap with six steps related to identifying patients with DoC, assessing for and treating confounders, establishing a diagnosis and prognosis, selecting interventions, and effectively communicating with family. This roadmap provides practical, evidence-informed guidance to help intensivists navigate diagnosis, treatment, and prognostication in patients with acute DoC. Advances in structural and functional neuroimaging, electrophysiology, and blood-based biomarkers offer promise for refined diagnostics and prognostication, though their clinical translation remains limited.