Blood pressure variability from intra-arterial pressure recordings in humans

Objectives: The study presents the magnitude of variation of systolic and diastolic pressures over a few minutes from intra-arterial pressure recordings in 51 hemodynamically stable patients in an intensive care unit. Materials and Methods: Conscious surgical ICU patients, with arterial pressure cannulae placed as the standard of care, were recruited after obtaining informed consent. A validated data acquisition system was used to record intra-arterial blood pressure for a period of 10 minutes following a Fast-Flush test. Only those recordings with acceptable dynamic characteristics as per Gardner’s criteria were included in the analysis. Results: Three categories of systolic and diastolic pressure variability namely “beat-to-beat” variability, “Respiratory” variability, and “Total magnitude of variation” during the duration of recording, were reported for each of the 51 patients. The mean (± SD) of the total magnitude of variation for systolic and diastolic pressures in the study sample were 21 ± 9 mmHg and 14 ± 5 mmHg respectively. Conclusion: Given the magnitude of systolic and diastolic pressure variations over a few minutes, the validity of reporting single- point values for these pressures and using single-point cut-offs for diagnosis and treatment of hypertension must be re-evaluated.