Placing a saline bag underneath the heart enhances transgastric transesophageal echocardiographic imaging during cardiac displacement for off-pump coronary artery bypass surgery

Objective The authors hypothesized that placing a saline bag (saline-filled surgical glove) underneath a displaced heart would improve ultrasound transmission for transgastric (TG) imaging and transesophageal echocardiography (TEE) to visualize left ventricular regional wall motion (LV-RWM) during cardiac displacement for off-pump coronary artery bypass (OPCAB) surgery. Design Prospective observational study. Setting Tertiary University Hospital. Participants Adult patients undergoing OPCAB surgery. Interventions Intraoperative TEE examination Measurement and Main Results For off-line analyses of LV-readable segments, mid-esophageal (ME, 4-chamber, 2-chamber, and long-axis) and TG (basal- and mid-short-axis) TEE views were recorded under 3 different intraoperative conditions in 13 cases of OPCAB surgery: Before cardiac displacement (T_control), after cardiac displacement (T _displaced), and after placing the saline bag underneath the displaced heart (T_saline-bag). There were more LV-readable segments in the 17-segment model using integrated ME and TG views(ME + TG views) at T _saline-bag and T_control (mean[95% confidence interval], 17[17-17] and 17[17-17]) than using ME+TG at T_displaced (15[15-16], P = 0.002 and P<0.001, respectively). Using ME + TG views provided more LV-readable segments in the 17-segment model than using ME views at T _saline-bag (vs. 16[14-16], P < 0.001), but not at T _displaced (vs. 15[14-15]). Incidences of inadequate RWM monitoring (LV-readable segments<14/17 using ME + TG views) at T_saline-bag and T_control (all 0/13) were less frequent than at T _displaced (3/13, all P = 0.038). There were more LV-readable segments in TG basal- and mid-short-axis views at T_saline-bag (median [range], 6[5-6] and 5[5-6]) than at T_displaced (0[0-2] and 0[0-1], all P < 0.05). Conclusions Placing a saline bag underneath the displaced heart enhances the ability of TEE to visualize global LV-RWM by improving TG TEE imaging during OPCAB surgery.