A beat-by-beat, on-line, cardiovascular index, CARDEAN, to assess circulatory responses to surgery: a randomized clinical trial during spine surgery

Automated assessment of circulatory response to surgical stimuli is unsolved. Would detection of cardiac baroreflex inhibition assess adequacy of intra-operative anti-nociception upon incision, as performed on-line on a beat-by-beat basis by a cardiovascular index, CARDEAN™? 18 ASA I-II patients undergoing spinal disc repair were studied, in a prospective randomized single-blinded trial (observational study). During infusion of propofol to maintain bispectral index between 40 and 60, patients were allocated to receive an effect site target-controlled infusion of remifentanil at Ce = 2 or 4 ng ml −1 . Upon incision and during surgery, circulatory response was assessed using beat-by-beat measurements of minor hypertension and tachycardia to give a cardiovascular index, CARDEAN, scaled between 0 and 100. Upon skin incision, CARDEAN increased in the remifentanil Ce = 2 ng ml −1 group (n = 7, P 60 was associated with tachycardia and hypertension ( P k = 0.81 ± 0.10). Changes in CARDEAN appeared linked to adequacy of anti-nociception.