EFFECT OF RESPIRATION ON PULSE WAVE VELOCITY MEASUREMENTS IN THE ARM: PP.8.314

Abstract

Introduction: Pulse Wave Velocity (PWV) in a vascular bed is determined significantly by the distending blood pressure (BP). Respiration influences systemic BP. Current guidelines for standardised measurement of PWV advise that recordings should be taken over a full respiratory cycle. No modern studies have quantified the degree to which respiration affects PWV measurements. We sought to assess the degree to which PWV in the arm will be affected by inspiration and expiration. Methods: Under standardised conditions PWV measurements were carried out in 10 volunteers during normal respiration. Thereafter PWV was measured during prolonged and help inspiration. Finally PWV was measured during prolonged and held expiration. Measurements were made in the carotid-radial segment (CRPWV) using applanation tonometry (SphygmoCor) and in the brachio-radial (BRPWV) segment using a piezoelectric system. Results: 10 volunteers completed the study, male = 6, mean age 31.2 years. None were on vasoactive medications. Mean CRPWV during normal respiration was 8.1 ± 0.6 m/sec. Mean BRPWV during normal respiration was 8.6 ± 1.4 m/sec. On the inspiration only studies a significant decrease was seen in CRPWV values (8.1 ± 0.6 m/sec vs 7.2 ± 0.7 p < 0.001, mean percentage change -11.2%) and BRPWV (8.6 ± 1.4 m/sec vs 7.8 ± 1.4 m/sec p = 0.005, mean percentage change -9.3%). During expiration CRPWV values increased from 8.1 ± 0.6 m/sec to 8.9 ± 0.8 m/sec (p = 0.002) with a mean percentage change from baseline was + 9.7%. BRPWV values also increased on the expiration only studies from 8.6 ± 1.4 m/sec to 9.3 ± 1.2 m/sec (p = 0.001), with a mean percentage change from baseline of + 7.8%. Conclusion: Deep respiration has significant effects on PWV measurements in the arm. This underlies the importance of measuring PWV in a relaxed patient over a full respiratory cycle.