Pulsatility index varies with different flowmeters in CABG surgery

PULSATILITY INDEX VARIES WITH DIFFERENT FLOWMETER DEVICES IN CABG SURGERY HB Nordgaard, N Vitale, F Onorati, F Pezzo, A Renzulli, R Haaverstad Objectives: Transit-time flowmetry (TTF) is the most common method of intraoperative assessment of coronary artery bypass grafts. TTF provides measurements of graft flow and the pulsatility index (PI = maximum flow – minimum flow/mean flow). It is assumed that PI values increase automatically at higher filter setting of the flowmeter because it allows recording of higher maximum flows. The aim of the study was to assess whether this assumption holds true by comparing PI values recorded by the Medistim (20Hz filter setting) or Transonic (5Hz filter setting) flowmeters. Methods: Graft flows and PI values were recorded in 584 patients by the Medistim flowmeter and 137 patients by the Transonic flowmeter. Data were analyzed retrospectively by ANOVA. Results: Table... There was a significantly lower PI with Transonic vs Medistim (mean difference 0.6). In one unit single and double sequential graft blood flows were significantly higher. Conclusions: The Transonic flowmeter showed a lower PI, probably due to a lower filter setting. Different blood flows may be found in different patients’ populations. Sequential grafts exhibited higher blood flows. Different filter settings in transit-time flowmeters may determine a different PI.