BACKGROUND: Continuous cardiac output measurement in STAT mode (STAT CCO) equipped with Vigilance displays cardiac output every 30 to 60 seconds. The aim of this study is to verify the hypothesis that each value with this system is computed only from the data collected in one update period. METHODS: The circuit was filled with normal saline and flowed by a roller pump in in vitro setting. The flow rate was set at either 2.5 l x min(-1) or 5.0 l x min(-1) and changed quickly to another state after each state had been maintained for 25 minutes. The change operation was repeated 10 times. The maximum difference was defined as the difference between the value at the start and the maximum change value. The response time was defined as the time from the start to the time to reach 80% of the maximum difference. In each operation, the response time of STAT CCO was calculated. RESULTS: The response time of STAT CCO was 9.7 +/- 1.3 min (mean +/- SD). CONCLUSIONS: The response time of STAT CCO was about 10 times longer than one update period. This result suggests that STAT CCO values are not computed only from the data collected in one update period.
BACKGROUND: Continuous cardiac output measurement in STAT mode (STAT CCO) equipped with Vigilance displays cardiac output every 30 to 60 seconds. The aim of this study is to verify the hypothesis that each value with this system is computed only from the data collected in one update period. METHODS: The circuit was filled with normal saline and flowed by a roller pump in in vitro setting. The flow rate was set at either 2.5 l x min(-1) or 5.0 l x min(-1) and changed quickly to another state after each state had been maintained for 25 minutes. The change operation was repeated 10 times. The maximum difference was defined as the difference between the value at the start and the maximum change value. The response time was defined as the time from the start to the time to reach 80% of the maximum difference. In each operation, the response time of STAT CCO was calculated. RESULTS: The response time of STAT CCO was 9.7 +/- 1.3 min (mean +/- SD). CONCLUSIONS: The response time of STAT CCO was about 10 times longer than one update period. This result suggests that STAT CCO values are not computed only from the data collected in one update period.