Objectives: Monitoring of brachial blood pressure during exercise-electrocardiogram (ECG) testing is mandatory and changes in blood pressure (BP) can provide critical management evidence. Patient movement, mechanical vibration, artifactual sounds and observer variability make standard manual techniques problematic. This was an investigator-initiated study to assess an automated auscultatory technique of BP assessment [Tango exercise blood pressure monitor (SunTech Medical Instruments, NC, USA)] to adequately measure BP during stress-ECG testing.
Methods: Initially five fit young male volunteers underwent invasive right brachial artery BP recording using a low-compliance fluid-filled catheter with simultaneous manual and automated assessment. Secondarily, during exercise-ECG testing, the system was assessed against beat-to-beat brachial blood pressures obtained from a catheter-tip solid-state pressure manometer positioned in the ipsilateral brachial artery.
Results: In the supine study overall mean difference (+/-SEM) between invasive and manual blood pressures was 3.26 (1.53) and 3.89 (1.90) mmHg for diastolic BP (DBP) and systolic BP (SBP) respectively. Corresponding differences between invasive and automated results, and manual and automated were 3.68 (0.84) and -7.31 (1.83) mmHg, and -0.64 (+/-1.43) and -11.42 (+/-1.59) mmHg. During treadmill exercise-ECG testing the combined mean difference (+/-SEM) between invasive and automated SBP and DBP was 4.79 (+/-0.14) and 6.33 (+/-0.10) mmHg, respectively.
Conclusion: Automated BP assessment during exercise-ECG testing is feasible with the use of appropriate automatic devices likely to be at least as accurate as manual BP registration. The Tango device is tolerant to exercise and provides reliable automatic BP assessment with absolute differences within an acceptable clinical range.