Dataset
The Japanese Registry of Pediatric Acute Care (JaRPAC) is a multicentre clinical database of ICU and PICU patients founded by the Japanese Society for Emergency Medicine. It was initiated in April 2014, with the aim of evaluating critically ill paediatric patients and reducing their mortality rate. The JaRPAC database contains anonymised information regarding patient demographics, admissions, treatment, and outcomes, as well as scoring systems for severity and mortality [9]. Paediatric patients aged ≤16 years admitted in ICUs or PICUs are eligible for inclusion in this registry, and data are available on a per capita basis. The data are collected from admission until discharge from the ICU or PICU. The National Center for Child Health and Development is the primary institute managing this registry data, and hospitals affiliated with this institute were selected to participate in the registry. This includes 12 PICUs in children’s hospitals and 11 ICUs at critical care centres.
Patients aged ≤16 years consecutively admitted to the ICU or PICU in a participating hospital between April 2014 (when the JaRPAC was started) and March 2017 were included in this study. This study was initiated to investigate patterns among patients admitted to the ICU or PICU from the emergency department; therefore, patients admitted to the ICU or PICU by postoperative management or deterioration in the general ward were excluded from the study (Fig. 1).
Ethical information
This study was approved by the Institutional Review Board of Juntendo University Urayasu Hospital, Chiba, Japan (30–025) and was conducted in accordance with the principles outlined in the 1964 Declaration of Helsinki and its later amendments. The need for informed consent was waived by the Institutional Review Board owing to the retrospective nature of the study. We followed the STROBE reporting guidelines while conducting this study.
Study design
This multicentre retrospective study was based on the data collected from JaRPAC. Data concerning the method of transport to the hospital were extracted from the database and divided into two groups, namely, transported by family members and by EMS. All patients admitted to the PICU or ICU first came through the emergency department. The cause of admission to the ICU or PICU was registered and classified into five categories: respiratory failure (requiring oxygenation or ventilatory support), circulatory failure (requiring circulatory support), neurological dysfunction, observation, and treatment for post-cardiopulmonary resuscitation. The final diagnosis of the patients in the case of intrinsic disease was coded based on the International Classification of Diseases v. 10 and categorised into one of nine groups to ensure sufficient patient numbers for analysis as follows: cardiovascular, respiratory, neuromuscular, congenital/genetic, gastrointestinal/hepatobiliary-pancreatic, hematologic/oncologic, renal, sepsis, and metabolic/endocrinologic groups [10, 11]. Extrinsic causes were categorised as trauma, asphyxia, poisoning, burns, drowning, suicide, or heatstroke. Chronic conditions were defined according to Feudtner et al.’s definition, which states that a chronic condition involves either several organ systems or one organ system severely enough to require speciality paediatric care and probably some period of hospitalisation in a tertiary care centre [12].
The Paediatric Index of Mortality 2 (PIM2) was used to measure disease severity in patients. The PIM2 score is calculated from various coefficients determined by Slater et al. [9]. The values used to calculate PIM2 resulted from the first face-to-face contact between patients and physicians at ICUs or PICUs. Data for some factors were not obtained for all cases; these factors were not included in the PIM2 calculations in these cases. Patient survival was defined as discharge from the ICU or PICU.
The duration of interventions performed in the ICU or PICU was compared between the groups. Interventions included invasive mechanical ventilation (IMV), non-invasive positive pressure ventilation continuous haemodiafiltration (CHDF), plasma exchange, polymyxin B-immobilised fibre column-direct haemoperfusion, extracorporeal membrane oxygenation (ECMO), intracranial cerebral pressure sensor placement, central venous access catheterisation (CV), peripherally inserted central catheterisation (PICC), and arterial line catheterisation (A-line).
Statistical analyses
Data regarding age, length of ICU or PICU stay, PIM2, and duration of interventions from JaRPAC were skewed, and medians with interquartile ranges were used for numerical variables. Numerical variable differences between the two groups were compared using the Mann-Whitney U test. The chi-square test was used to compare sex distribution as well as mortality, time of admission, reasons for admission, and final diagnosis. Data regarding mortality, transport distance and chronic condition status were analyzed by age category and PIM2 risk intervals. To assess the independent effect of transportation type, multivariable logistic regression analysis of survival was performed. PIM2, chronic condition status and transport distance were included as variables of multivariable logistic analysis. Data management and statistical analyses were performed using EZR software (Y Kaneda, Saitama Medical Center, Jichi Medical University, Saitama, Japan). A p value < 0.01 was considered significant.