Background and aims Sternotomy for coronary artery bypass surgery is associated with episodes of hypertension and tachycardia despite adequate level of anaesthesia, thus increasing the risk of myocardial ischemia. This study was designed to assess the effect of preoperative parasternal block (PSB) on anaesthetic agents consumption required to maintain hemodynamic stability during sternotomy.

Methods After approval of the Ethics Committee and written informed consent, 20 patients were enrolled in this prospective, randomized, double-blind study. Aneasthesia was induced with Propofol and Remifentanil using target-controlled infusion, guided by the patient state index (PSI_25-50) and the hemodynamic response: blood pressure (BP) and heart rate (HR). Block was performed under ultrasound with 60 ml of 0.25% Ropivacaine (Group PSB) or normal saline (Group CTL), divided into 4 injections (2 per side of the sternum), between the pectoralis major and intercostal muscles. Maximal dose of Remifentanil and Propofol used to maintain the hemodynamic stability during sternotomy were measured. Halogenated anaesthetic requirement was noted. BP, HR, and PSI were measured every minute until 5 minutes after the retractor placement. Mann-Whitney test was used to analyze quantitative variables and Fisher’s-exact test for categorical variables.

Results Demographic data are presented in table 1. PSB significantly reduced consumption of anaesthetic agents during sternotomy, including the use of halogens and maintained PSI in higher values (table 2). No difference was observed regarding postoperative complications.

Conclusions Preoperative PSB prevents hemodynamic instability during sternotomy, without increasing anaesthetic agent consumption. It allows a better stability of anaesthesia depth. Its impact on postoperative pain should be assessed.