Characteristics of In-Hospital Patients with Congenital Heart Disease Requiring Rapid Response System Activations: A Japanese Database Study

Objectives: This study aimed to study the characteristics of in-hospital deterioration in patients with congenital heart disease who required rapid response system activation and identify risk factors associated with 1-month mortality. Methods: We retrospectively analysed data from a Japanese rapid response system registry with 35 participating hospitals. We included consecutive patients with congenital heart disease who required rapid response system activation between January 2014 and March 2018. Logistic regression analyses were performed to examine the associations between 1-month mortality and other patient-specific variables. Results: Among 9,607 patients for whom the rapid response system was activated, only 82 (0.9%) had congenital heart disease. Only few patients with congenital heart disease were being treated at the cardiology and cardiovascular surgery departments (12.3% and 9.9%, respectively). Moreover, the incidences of rapid-response events after intensive care unit discharge or surgery were low (6.8% and 12.2%, respectively). The most common reason for rapid response system activation was respiratory dysfunction (desaturation: 35.4%, tachypnoea: 25.6%, and new dyspnoea: 195%). Rapid response system interventions and intensive care unit transfers were required for 65.9% and 20.7% of patients, respectively. The mortality rate was 1.2% at the end of the rapid response system intervention and 11.0% after 1 month. Moreover, decreased respiratory rate and decreased heart rate at rapid response system activation were associated with increased 1-month mortality. The adjusted odds ratio was 1.10 (95% confidence interval 1.02-1.19) and 1.02 (95% confidence interval, 1.00-1.04 for respiratory rate and heart rate, respectively. Conclusions: Rapid response systems were rarely activated after cardiac surgery and intensive care unit discharge, which were situations with a high risk of sudden deterioration in patients with congenital heart disease. Therefore, encouraging the use of the rapid response system in these departments will enable intervention by a third, specialised team for in-hospital emergencies and help provide comprehensive medical care to patients. Furthermore, 1-month mortality was associated with vital signs at rapid response system activation. These findings may guide treatment selection for patients with congenital heart disease showing deterioration.