Error grid analysis for risk management in the difference between invasive and noninvasive blood pressure measurements.

PURPOSE

Invasive arterial blood pressure (IAP) and noninvasive blood pressure (NIBP) measurements are both common methods. Recently, a new method of error grid analysis was proposed to compare blood pressure obtained using two measurement methods. This study aimed to compare IAP and NIBP measurements using the error grid analysis and investigate potential confounding factors affecting the discrepancies between IAP and NIBP.

METHODS

Adult patients who underwent general anesthesia in the supine position with both IAP and NIBP measurements were retrospectively investigated. The error grid analyses were performed to compare IAP and NIBP. In the error grid analysis, the clinical relevance of the discrepancies between IAP and NIBP was evaluated and classified into five zones from no risk (A) to dangerous risk (E).

RESULTS

Overall, data of 1934 IAP/NIBP measurement pairs from 100 patients were collected. The error grid analysis revealed that the proportions of zones A-E for systolic blood pressure were 96.4%, 3.5%, 0.05%, 0%, and 0%, respectively. In contrast, the proportions for mean blood pressure were 82.5%, 16.7%, 0.8%, 0%, and 0%, respectively. The multiple regression analysis revealed that continuous phenylephrine administration (p = 0.016) and age (p = 0.044) were the significant factors of an increased clinical risk of the differences in mean blood pressure.

CONCLUSIONS

The error grid analysis indicated that the differences between IAP and NIBP for mean blood pressure were not clinically acceptable and had the risk of leading to unnecessary treatments. Continuous phenylephrine administration and age were the significant factors of an increased clinical risk of the discrepancies between IAP and NIBP.