An evaluation of a new continuous blood pressure monitoring system in critically ill patients

• Published in: Journal of clinical anesthesia 2000-11, Vol.12 (7), p.509-518
• Main Authors: Heard, Stephen O, Lisbon, Alan, Toth, Ildiko, Ramasubramanian, Ramiah
• Format: Article
• Language: English
• Subjects: Arterial blood pressure, noninvasive; Biological and medical sciences; Blood Pressure Determination - instrumentation; Calibration; Cardiovascular system; Critical Illness; electrocardiogram; Female; Humans; Intensive Care Units; Investigative techniques of hemodynamics; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; plethysmography; Prospective Studies
• ISSN: 0952-8180; 1873-4529
• DOI: 10.1016/S0952-8180(00)00201-4

Study Objective: To determine if the DxTek monitor, which is a device that measures blood pressure (BP) noninvasively and continuously by means of pulse velocity and wave shapes derived from the pulse oximeter optical plethysmograph and electrocardiogram is as accurate as an oscillometric cuff device when compared with intraarterial BP measurement. Design: Prospective, comparative study. Setting: University Medical Center. Patients: 28 intensive care unit patients. Interventions: Blood pressures were reported every minute by intraarterial catheters and DxTek and every 10 minutes by an oscillometric monitor for 2 to 5 hours. DxTek calibration was performed initially and when specified patient manipulations by caretakers were performed (on average, every 100 minutes). Comparisons with intraarterial pressure included: 1) DxTek calibrated with arterial catheter pressure, 2) DxTek calibrated with oscillometric pressure, and 3) oscillometric pressure. Measurements and Main Results: When comparing oscillometric pressure to intraarterial pressure, the averages of the mean differences (bias) were −4.0 mmHg for systolic (SBP) and < 1.5 mmHg for diastolic (DBP) and mean (MAP) pressures. The averages of the standard deviation of the differences (precisions) were 9.6, 6.4, and 6.3 mmHg, respectively. With the DxTek device calibrated to intraarterial pressure, comparison of the DxTek pressure to intraarterial pressure resulted in a bias ≤0.5 mmHg for all three pressures and an average precision of 10.1 mmHg for SBP, 6.0 mmHg for DBP, and 6.7 mmHg for MAP. With the DxTek device calibrated to the oscillometric pressure, the DxTek pressure compared to the intraarterial pressure resulted in average biases of −5.1, −0.8, and −2.2 mmHg and average precisions of 11.1, 7.7, and 8.1 mmHg for SBP, DBP, and MAP, respectively. Conclusions: The DxTek monitor provides continuous, noninvasive BP measurements with an accuracy comparable to oscillometric devices.