Efficacy of high-frequency jet ventilation in cardiac tamponade

To evaluate the effects of high-frequency jet ventilation (HFJV) (f = 60, 120 breaths/min) and conventional mechanical ventilation (CMV) (f = 10, 20) during equivalent conditions of cardiac tamponade, stroke index (SI), intrapericardial pressure (IPP), airway pressure (P(aw)), and cardiac pressures were measured in anesthetized, paralyzed, chest-closed dogs with the same levels of PaCO2. Cardiac tamponade was produced by infusing normal saline into the intrapericardial space to increase IPP to either 8 mm Hg (group 1, n = 8) or 12 mm Hg (group 2, n = 8). Stroke index in group 1 was 7.3 +/- 0.8 during CMV (f = 10), 8.1 +/- 0.7 during CMV (f = 20), 10.9 +/- 1.4 during HFJV (f = 60), and 10.7 +/- 1.2 (mL.beat-1.m-2) during HFJV (f = 120). Stroke index in group 2 was 4.1 +/- 0.7, 5.1 +/- 0.5, 7.2 +/- 0.5, and 6.7 +/- 0.5 (mL.beat-1.m-2), respectively. In both IPP groups, stroke index values during HFJV were significantly higher than during CMV; however, there were no significant differences in mean left and right atrial transmural pressures between HFJV and CMV. Peak IPP, mean P(aw), and peak P(aw) during HFJV were significantly lower than those during CMV. The results indicate that HFJV with lower mean and peak Paw, and with lower mean and peak IPP, can result in higher cardiac output than CMV in cardiac tamponade. Thus, HFJV may be superior to CMV in the clinical management of cardiac tamponade.