Variation in use of peroperative inotropic support therapy in cardiac surgery: time for reflection?

Abstract

There is no well-established evidence-based clinical guidelines on the most appropriate use of peroperative inotropic support in cardiac surgery. We aimed to identify patient- and procedure-related factors associated with the use of peroperative inotropic support and to estimate physician-level variation. A population-based study using data from the Western Denmark Heart Registry on 3585 consecutive cardiac surgery cases from three university hospitals. Inotropic support was defined as infusion of inotropic drugs or nor epinephrine at the separation from cardiopulmonary bypass. Poisson's regression modelling was used to determine predictors of inotropic support and to compare use of high-dose inotropic support among experienced cardiac anaesthesiologists. We identified a range of factors that were independently associated with an increased use of inotropic support therapy including pre-operative left ventricular dysfunction, pre-operative renal dysfunction, complex procedures, prior cardiac surgery, emergency surgery, pre-operative pulmonary hypertension, critical pre-operative state, extended extra corporal circulation-time and female gender. Further, we found substantial variation in use of inotropic support both at hospital- and at physician-level. The adjusted odds ratio of high-intensity inotropic support varied significantly at physician level from 2.3 [95% confidence interval (CI) 1.83-2.71] to 0.3 (95% CI 0.15-0.61) when the individual physicians were compared with the rest. The use of inotropic support during cardiac surgery is associated with the pre-operative state of the patient, as well as type of surgery. However, the present study indicates that use of peroperative inotropic support is also highly dependent on physician's preferences, indicating the need for an evidence-based approach when initiating inotropic therapy in cardiac surgery.