title: Evaluation of noninvasive blood pressure recording by photoplethysmography in clinical studies using angiotensin challenges.
abstract: OBJECTIVE
  Continuous noninvasive blood pressure measurement by photoplethysmography has been regularly used in the experimental paradigm of angiotensin challenges, applied to the phase I clinical testing of angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists. This work aims to evaluate the performance of this measurement method, in terms of reliability, reproducibility and dependence on technical settings.
  
  
  METHODS
  Data have been gathered from 13 clinical studies on antihypertensive drugs, using the Finapres device for measuring the response to exogenous angiotensin challenges. The agreement between simultaneous recordings at different fingers and the influence of the reading method are assessed. A literature review addresses the question of the concordance between results obtained noninvasively and through arterial cannulation.
  
  
  RESULTS
  The relative precision of blood pressure monitoring by photoplethysmography allows reproducible determination of angiotensin-induced blood pressure peaks (agreement limits for systolic and diastolic peaks: 12 and 6 mmHg respectively). The reading method influences the results to a similar extent. As compared with blood pressure measured intra-arterially, the difference is usually within limits of clinical acceptability.
  
  
  CONCLUSIONS
  In the context of phase I studies using the angiotensin challenges methodology, the reliability and reproducibility of noninvasive blood pressure measurement appear satisfactory, despite the technical limitations of this method. The impact of selected changes in the settings and reading methods is limited.
authors.affiliation: Division of Clinical Pharmacology, CHUV, Lausanne, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Buclin
authors.forename: C
authors.initials: C
authors.lastname: Buchwalder-Csajka
authors.forename: H R
authors.initials: HR
authors.lastname: Brunner
authors.forename: J
authors.initials: J
authors.lastname: Biollaz
mesh_terms: D000804:Angiotensin II / Q000037:antagonists & inhibitors*; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology*; D001795:Blood Pressure Determination / Q000379:methods*; D017321:Clinical Trials, Phase I as Topic; D003201:Computers; D003625:Data Collection; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006973:Hypertension / Q000188:drug therapy; D017156:Photoplethysmography / Q000379:methods; D012044:Regression Analysis; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000804:Angiotensin II