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Abstract Comprehending the resilience of regional hydroclimate in response to CO2 removal is essential for guiding future mitigation and adaptation strategies. Using an ensemble of model simulations forced by idealized CO2 ramp-up followed by ramp-down, here we show that the winter precipitation over the Northeastern Pacific and Western North America (NPWNA) is irreversible even if global warming is reversed back to 2 °C level. This asymmetric change features a tripolar pattern and is tied to Aleutian Low intensification, which is driven by both zonal and meridional gradients of sea surface temperature (SST) anomalies in the tropical central-eastern Pacific. Distinct from the zonal SST gradient—explained by different timescales of surface and subsurface warming and ocean dynamical processes, amplified through the Bjerknes feedback—the meridional SST gradient originates from the southward shift of the intertropical convergence zone, maintained by the wind-evaporation-SST feedback. Our findings suggest that the regional hydrological risks over the NPWNA induced by CO2 ramp-up cannot be fully eliminated by CO2 removal even if the global warming level is restored back.

Abstract Aim To determine whether the rewarming rate is associated with neurological outcomes in patients with post–cardiac arrest syndrome treated with targeted temperature management (TTM) at 34°C. Methods We conducted a retrospective analysis of a nationwide cohort study of out‐of‐hospital cardiac arrest in Japan. Adult patients who experienced a return of spontaneous circulation and completed TTM at 34°C between June 2014 and December 2019 were divided equally into three groups (slow, moderate, and rapid) according to their rewarming rates from 34°C to 36°C. The rates of favorable neurological outcomes (Cerebral Performance Category of 1–2 after 30 days) were compared among the groups, and the adjusted odds ratios for a favorable neurological outcome were calculated for the groups. Results We analyzed 348, 357, and 358 patients in the slow, moderate, and rapid groups, respectively. The periods of rewarming from 34°C to 36°C were 41.9 ± 10.5, 22.4 ± 1.8, and 12.2 ± 3.6 h, respectively. The number of favorable neurological outcomes after 30 days was 121 (34.8%), 125 (35.0%), and 147 (41.1%), respectively, with no significant differences among the three groups (p = 0.145). Rapid rewarming was independently associated with a favorable neurological outcome compared with slow rewarming (adjusted odds ratio 1.57 [95% confidence interval 1.04–2.37]; p = 0.031). Conclusions Rapid rewarming after TTM at 34°C was associated with a more favorable neurological outcome than slow rewarming.

Abstract Aim To determine whether dispatcher‐provided cardiopulmonary resuscitation (CPR) instructions improve the outcomes of out‐of‐hospital cardiac arrest (OHCA). Methods Cases registered in the Japanese Association for Acute Medicine Out‐of‐Hospital Cardiac Arrest (JAAM‐OHCA) Registry between June 2014 and December 2019 were included. Cases in which the dispatcher provided CPR instructions to the bystander were included in the “Instructions” group”, and cases without CPR instructions were included in the “No Instructions” group. The primary outcome was the proportion of patients with a favorable neurological outcome, defined as a Glasgow–Pittsburgh cerebral performance category scale of 1 to 2 at 1 month after OHCA. Results Overall, 51,199 patients with OHCA were registered in the JAAM‐OHCA Registry during the study period. Of these, 33,745 were eligible for the study, with 16,509 in the Instructions group and 17,236 in the No Instructions group. The proportion of patients with a favorable neurological outcome at 1 month after OHCA was inferior in the Instructions group than in the No Instructions group (2.3% versus 3.0%, p

Aim To assess whether the outcomes of out‐of‐hospital cardiac arrest (OHCA) differ between patients treated at tertiary or secondary emergency medical facilities. Methods Data from the Japanese Association for Acute Medicine Out‐of‐Hospital Cardiac Arrest (JAAM‐OHCA) registry between June 2014 and December 2015 were analyzed and compared between patients treated at tertiary (tertiary group) and secondary (secondary group) emergency medical facilities. The primary outcome of this study was a favorable neurological outcome at 1 and 3 months after OHCA, defined as a Glasgow–Pittsburgh cerebral performance category of 1 or 2. Results Between June 2014 and December 2015, a total of 13,491 patients with OHCA were registered in the JAAM‐OHCA registry. Of these, 12,836 were eligible in the present analysis, with 11,583 in the tertiary group and 1,253 in the secondary group. The proportions of patients with favorable neurological outcomes in the tertiary group were significantly higher than those in the secondary group at 1 (4.7% versus 2.0%, P

BackgroundThe purpose of this study was to clarify the practical clinical treatment for acute carbon monoxide (CO) poisoning in Japan and to investigate the efficacy of hyperbaric oxygen (HBO2) therapy in preventing delayed neurological sequelae (DNS) in the acute phase of CO poisoning.MethodsWe conducted a multicenter, prospective, observational study of acute CO poisoning in Japan. Patients with acute CO poisoning were enrolled and their treatment details were recorded. The primary endpoint was the onset of DNS within 2 months of CO exposure. Factors associated with DNS were assessed with logistic regression analysis.ResultsA total of 311 patients from 57 institutions were registered and 255 were analyzed: 171 received HBO2 therapy (HBO2 group) and 84 did not (normobaric oxygen [NBO2] group). HBO2 therapy was performed zero, once, twice, or three times within the first 24 h in 1.8%, 55.9%, 30.9%, and 11.3% of the HBO2 group, respectively. The treatment pressure in the first HBO2 session was 2.8 ATA (47.9% of the HBO2 group), 2.0 ATA (41.8%), 2.5 ATA (7.9%), or another pressure (2.4%). The incidence of DNS was 13/171 (7.6%) in the HBO2 group and 3/84 (3.6%) in the NBO2 group (P = 0.212). The number of HBO2 sessions in the first 24 h was one of the factors associated with the incidence of DNS (odds ratio, 2.082; 95% confidence interval, 1.101-3.937; P = 0.024).ConclusionsThe practical clinical treatment for acute CO poisoning, including HBO2 therapy, varied among the institutions participating in Japan. HBO2 therapy with inconsistent protocols showed no advantage over NBO2 therapy in preventing DNS. Multiple HBO2 sessions was associated with the incidence of DNS.

Background. The aim of this study was to identify practice differences in the treatment of carbon monoxide (CO) poisoning with or without hyperbaric oxygen (HBO2) therapy in Japan. Materials and Methods. Using an online survey website (Google form), we created a questionnaire and invited interested institutions to join the COP-J Study, a prospective observational study of CO poisoning in Japan. Results. Forty-eight (63%) of 76 institutions replied to the questionnaire. Thirty-three institutions (69%) administered HBO2 therapy to patients with CO poisoning, and 15 institutions (31%) did not. Consciousness disturbance on arrival, exposure to CO for a long time, and elevation of arterial carboxyhemoglobin (CO-Hb) were the major indications for HBO2 therapy. The maximum therapeutic pressures were 2.0, 2.5, and 2.8 atmospheres absolute (ATA) at 19 (58%), 6 (18%), and 8 (24%) institutions, respectively. The number of HBO2 sessions on the first day was 1–3, and 1–7 sessions were administered on days 2–7. Seventeen (35%) institutions treated patients with delayed neurological sequelae (DNS) and 15 of them used HBO2 therapy for DNS. Conclusions. This survey indicates that HBO2 therapy for CO poisoning was varied in both the indications and practice regimens used in Japan.