Role of a rapid response system and code status discussion as determinants of prognosis for critical inpatients: An observational study in a Japanese urban hospital

Rapid response systems (RRS) have been introduced worldwide to reduce unpredicted in-hospital cardiac arrest (IHCA) and in-hospital mortality. The role of advance care planning (ACP) in the management of critical patients has not yet been fully determined in Japan. We retrospectively assessed the characteristics of all inpatients with unpredicted IHCA in our hospital between 2016 and 2018. Yearly changes in the number of RRS activations and the incidence of unpredicted IHCA with or without code status discussion were evaluated from 2014 to 2018. Hospital standardized mortality ratios were assessed from the data reported in the annual reports by the National Hospital Organization. A total of 81 patients (age: 70.9 ± 13.3 years) suffered an unpredicted IHCA and had multiple background diseases, including heart disease (75.3%), chronic kidney disease (25.9%), and postoperative status (cardiovascular surgery, 18.5%). Most of the patients manifested non-shockable rhythms (69.1%); survival to hospital discharge rate was markedly lower than that with shockable rhythms (26.8% vs 72.0%, P < .001). The hospital standardized mortality ratios was maintained nearly constant at approximately 50.0% for 3 consecutive years. The number of cases of RRS activation markedly increased from 75 in 2014 to 274 patients in 2018; conversely, the number of unpredicted IHCA cases was reduced from 40 in 2014 to 18 in 2018 (P < .001). Considering the data obtained in 2014 and 2015 as references, the RRS led to a reduction in the relative risk of unpredicted IHCA from 2016 to 2018 (ie, 0.618, 95% confidence interval 0.453–0.843). The reduction in unpredicted IHCA was attributed partly to the increased number of patients who had discussed the code status, and a significant correlation was observed between these parameters (R(2) = 0.992, P < .001). The reduction in the number of patients with end-stage disease, including congestive heart failure and chronic renal failure, paralleled the incidence of unpredicted IHCA. Both RRS and ACP reduced the incidence of unpredicted IHCA; RRS prevents progression to unpredicted IHCA, whereas ACP decreases the number of patients with no code status discussion and thus potentially reducing the patient subgroup progressing to an unpredicted IHCA.