The Japanese accidental hypothermia network registry (J-Point registry)
J-Point registry aimed to obtain descriptive information about AH towards understanding its management in the EDs of Japan, to improve patient outcomes. Details of the study methodology were described previously.9 In brief, twelve acute care hospitals with EDs including eight critical care medical centers across the Kyoto, Osaka and Shiga Prefectures in Japan joined the J-Point registry. We retrospectively enrolled eligible patients with the International Classification of Diseases, Tenth Revision (ICD-10) code for hypothermia (T68) during the study period. The ethics committee of each participating institution approved this study.
Data collection and quality control
In this registry, data on the characteristics of the participants, clinical history, presentation, laboratory findings, and treatments were collected using a predefined uniform data sheet. All chart reviewers were emergency physicians who were trained for appropriate data review by face-to-face or web meetings. The collected data were reviewed by the working group and confirmed or returned to each institution in case of any problems.
The Baseline characteristic information was following: sex, age, activities of daily living (ADL) before being hypothermic (independent, need some assistance, and need total assistance), residence (living alone at home, not living alone at home, nursing home, and homelessness), past medical history (cardiovascular diseases [ischemic heart diseases, heart failure, arrhythmia, hypertension, and other cardiovascular diseases], neurological diseases [stroke, epilepsy, Parkinson disease or syndrome, and other neurological diseases], endocrine diseases [diabetes mellitus, thyroid diseases, adrenal insufficiency, and other endocrine diseases], psychiatric diseases [chronic alcoholism, depression, schizophrenia, and other psychiatric diseases], malignant diseases, dementia, mean outside temperature of the day upon the occurrence of AH, season, location (indoor and outdoor), mode of arrival (walk-in and via ambulance), vital signs upon hospital arrival (body temperature, blood pressure, heart rate, and Glasgow Coma scale [GCS] score), biological data (serum pH, HCO3 [mEq/L], lactate [mmol/L], sodium [mEq/L], potassium [mEq/L], and glucose [mg/dL] levels), exposure to cold, associated conditions, treatment process, and outcome. Sequential organ failure assessment (SOFA) score was calculated only for patients admitted to the ICU. Based on previous reports,3,[i] associated conditions were classified into internal diseases (stroke, seizure, Parkinson disease, thyroid diseases, hypoglycemia, infectious diseases, acute pancreatitis, uremia, malignant disease, bowel ischemia, rhabdomyolysis, or other internal diseases), trauma (fall [injury in the head, spine, and extremity], motor vehicle accident, or other traumatic injuries), alcohol intoxication, drowning (indoor or outdoor), self-harm (drug or external), and other factors (iatrogenic, mountain incident, burn, malnutrition/infirmity, or others). Rewarming procedures were divided into active external or minimally invasive rewarming (warm intravenous fluids, warm blanket, forced warm air, heating pads, and warm bath) and active internal rewarming (lavage [stomach, chest, and bladder], intravascular rewarming, hemodialysis, and extra corporeal membrane oxygenation [ECMO]). Other treatment information included tracheal intubation, use of catecholamine, and emergent transvenous cardiac pacing. Data regarding outcomes were in-hospital death, and length of hospital and ICU stay.
Data were analysed using the Mann–Whitney U test for continuous variables and Fisher’s exact test for comparing categorical variables between CCMC and non-CCMC. The association between care at CCMC and in-hospital death was analysed via univariable and multivariable logistic regression. We calculated the odds ratios (ORs) and adjusted odds ratios (AORs) and their 95% confidence interval (CI) as the effect variables. Based on previous studies,3,9,10 we selected potential confounders that are likely to be associated with clinical outcomes and adjusted for the following: age category (18-64 years, 65-74 years, and ≥75 years), sex (male or female), past medical history (none, one, multiple, and unknown), ADL (independent, need some assistance, need total assistance, or unknown), systolic blood pressure category (cardiac arrest, unmeasurable, 40-90 mmHg, or >90 mmHg), exposure to cold (yes, no, or unknown), presence of associated internal diseases (yes or no), and active internal rewarming (yes or no). For subgroup analyses, the association between care at the specialized center and in-hospital death was investigated according to patients with severe hypothermia (<28°C) or systolic blood pressure of <90 mmHg via univariable and multivariable logistic regression analysis adjusting for the same confounders described above. All P-values were two-sided, and <0.05 was considered statistically significant. All statistical analyses were conducted the EZR software (version 1.36).