Invasive blood pressure recording comparing nursing charts with an electronic monitor: A technical report

Background: Blood pressure management (assessed using nursing charts) in the early phase of septic shock may have an effect on renal outcomes. Assessment of mean arterial pressure (MAP) values as recorded on nursing charts may be inaccurate. Aim: To determine the difference between hourly blood pressure values as recorded on the nursing charts and hourly average blood pressure values over the corresponding period obtained electronically from the bedside monitor. Methods: We studied 20 patients with shock requiring vasopressor support and invasive blood pressure monitoring. Hourly blood pressure measurements were recorded on the nursing charts over a 12-hour period. Blood pressure values recorded every 10 minutes were downloaded from electronic patient monitors over the corresponding period. The hourly average of the 10-minute blood pressure values was compared with the measurements recorded on the nursing charts. Results: We assessed 240 chart readings and 1440 electronic recordings. Average chart MAP was 72.54 mmHg and average electronic monitor MAP was 71.54 mmHg. MAP data from the two sources showed a strong correlation (?= 0.71, P < 0.005). Bland-Altman assessment revealed acceptable agreement, with a mean bias of 1mmHg and 95% limits of agreement of -11.76 mmHg and 13.76 mmHg. Using average data over 6 hours, 95% limits of agreement narrowed to -6.79mmHg and 8.79mmHg. Conclusion: With multiple measurements over time, mean blood pressure as recorded on nursing charts reasonably approximates mean blood pressure recorded on the monitor.