Evaluation of reproducibility of plethysmographic indices according to body posture, choice of forearm and method of measurement

• Published in: Polskie archiwum medycyny wewne̦trznej Vol. 104; no. 3; p. 575
• Main Authors: Neubauer, J, Bieniaszewski, L, Kruszewski, P, Swierblewska, E, Juzwa, W, Krupa-Wojciechowska, B
• Format: Journal Article
• Language: Polish
• Published: Poland 01-09-2000
• Subjects: Adult; Forearm - blood supply; Humans; Male; Middle Aged; Plethysmography - methods; Plethysmography - standards; Posture - physiology; Reference Values; Regional Blood Flow; Reproducibility of Results; Supine Position
• ISSN: 1897-9483

The aim of the study was the analysis of the influence: a) body position (sitting vs. supine), b) choice of the arm (dominant vs. nondominant), c) variant of the method (classic vs. automatic) on plethysmographic indices describing forearm blood flow repeatability (arterial inflow--AI, fast blood flow--FBF, venous outflow VO, venous capacitance--VC). The study group included subjective healthy men, aged from 22 to 60 years. Individuals with body mass index (BMI) > 35 kg/m2 or treated pharmacologically weren't been included into examination. The indices of the forearm blood flow were calculated from the plethysmographic curve using the graphic technique: venous capacitance (VC), arterial inflow (AI), fast blood flow (FBF) and venous outflow (VO). We used relative repeatability coefficient (RRC) and coefficient of variation (CV) for assessing repeatability of obtained parameters. Repeatability of plethysmographic indices was better in supine position than in sitting one. RRC was respectively for supine vs. sitting position for VO: 0.41 vs. 0.68, for VC: 0.42 vs. 0.52 and for AI: 0.57 vs. 0.65. Plethysmographic indices VO, VC, AI were characterised by better repeatability when the exams were performed on the dominant arm. RRC was respectively for dominant vs. nondominant arm for VO: 0.68 vs. 0.71, for VC: 0.52 vs. 0.64 and for AI: 0.65 vs. 0.71. Coefficient of variation of arterial inflow assessed by conventional, automatic and by fast inflow was respectively 20%, 23% and 17%. The long-term repeatability of FBF estimated by RRC was 0.76 whereas CV yielded 17%. The same coefficient of variation was obtained when short-term repeatability was estimated-mean value CV was 17%, after rejection extremal values 11%. In conclusion the best repeatability was obtained when measurements were performed with automatic variant of method, in supine position, on dominant arm.