An earthquake with a magnitude of 8 or 9 is predicted to occur near the Ryukyu Islands in Japan, for which the Okinawa Prefecture is preparing countermeasures. Evacuating people to a safe shelter within the tsunami arrival time is a crucial countermeasure. This study aims to understand the vulnerabilities of patients with chronic respiratory diseases in southern parts of Okinawa during a tsunami evacuation, thereby calculating evacuation distance of vulnerable patients and creating individual evacuation plans. Data for chronic respiratory patients obtained in July 2021 from the hospitals in Okinawa Prefecture include age, gender, diagnosis, residence, nearest tsunami shelter, oxygen flow at rest and walking, and maximum walking distance for 6 min based on a 6-min walk test. A quantum geographic information system was used for mapping the data. The survival potential of patients with chronic respiratory disease was evaluated by using a tsunami inundation depth of one meter and the distance within which an evacuation can be performed until the first tsunami wave reaches the nearest evacuation shelter. Results revealed a low survival potential for respiratory disease patients under the current tsunami evacuation plan. The study suggests creating an individual evacuation plan for vulnerable patients involving families and medical staff and then conducting a drill for improving the plan.

Background: Time-based criteria for mechanical ventilation (MV) liberation in tracheostomized patients undergoing T-tube trials with ventilator discontinuation are inconsistent. We aimed to define the minimum post-liberation observation time and identify factors associated with successful liberation.Methods: This single-center retrospective cohort study included adults with tracheostomy who received MV in the intensive care unit and high care unit of a Japanese hospital from November 14, 2019, to August 31, 2024. We measured maximum endurance time (MET) without MV, MV liberation success, and the shortest MET when success first exceeded 80% (mini-MET). Time to mini-MET was assessed by Kaplan-Meier median survival time (MST), and competing risk analysis treating in-hospital death as a competing event was performed. Predictors were screened by univariate C-index, and survival tree cutoffs were examined using logistic regression sensitivity analyses.Results: Among 160 patients, MV liberation success increased with MET from 65% to 94% at 168 hours. The MST to achieve the mini-MET, which was identified as 4 hours, was 7 days (95% CI, 5–10 days). Mechanical power normalized by dynamic compliance (MPCdyn) ≤454.72 J/min and albumin >2.3 g/dl were associated with success. MST was 3 days when both were satisfied. In a covariate-adjusted model, low MPCdyn plus high albumin remained associated with success. Replacing MPCdyn with driving pressure yielded similar findings.Conclusions: Four hours may be a practical minimum post-liberation observation time, whereas 48 hours may be a conservative option. Stratification by MPCdyn or driving pressure plus albumin can support consistent MV liberation decisions after tracheostomy.