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Non-invasively determined ambulatory venous pressureDepartment of Surgery, University of California, San Diego, CA, USA, Departments of Bioengineering, University of California, San Diego, CA, USA, Veterans Administration Medical Center, San Diego, CA, USA
Department of Bioengineering, University of California, San Diego, CA, USA
Veterans Administration Medical Center, San Diego, CA, USA In view of the resemblance of exercise-induced plethysmographic changes with those obtained by direct venous pressure measurement, we decided to use a combination of photo-plethysmography (PPG) and hydrostatic pressure calibration to determine the PPG/pressure relationship. A standard foot dorsiflexion exercise involving stepwise position changing was performed which induced hydrostatic pressure changes that were recorded as the heart-probe distance. A logarithmic PPG/pressure relationship was identified and the resulting ambulatory venous pressure (AVP) was obtained from the PPG/pressure curve. Simultaneous direct AVP was recorded in 14 patients scheduled for venous surgery. `Non-invasive AVP only' was determined in 24 normal control subjects with a mean value of 19.24 mmHg (±8.79 SD). In the patient group, the direct AVP values were 40.00 mmHg (±10.83 SD) compared with the PPG values of 33.07 mmHg (±12.94 SD). The resulting correlation was r = 0.8850. By utilizing stepwise leg elevation, a reliable PPG/pressure curve can be established which, in turn, permits AVP determination. It is suggested that this non-invasive AVP determination may serve as a screening test to evaluate non-invasively venous hemodynamics.
Key Words: ambulatory venous pressure • photoplethysmography
Vascular Medicine, Vol. 5, No. 4,
213-216 (2000) This article has been cited by other articles:
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