Impact of Valsalva maneuver duration on brain function in patients undergoing high-intensity focused ultrasound liver ablation: a randomized controlled trial.

BACKGROUND

Intermittent Valsalva maneuver (VM) is commonly used to facilitate high-intensity focused ultrasound (HIFU) ablation. However, the optimal duration of a VM in terms of adverse impacts on brain function is unknown. This prospective study explored the impact of different VM durations on brain function in patients undergoing HIFU ablation surgery for hepatic cancer.

METHODS

Adult patients scheduled for HIFU ablation for liver cancer under general anesthesia were randomized into a control group, ≤5.2 min per VM episode (short VM group), or >5.2 min per VM episode (long VM group). A four-channel electroencephalogram was conducted using SedLine to record brain electrical parameters (e.g., power spectral density, entropy values, and cross-frequency domain coupling). The primary endpoint was burst suppression in the intent-to-treat population that included all enrolled subjects. Key secondary endpoints included postoperative delirium, emergence agitation, and postoperative recovery quality.

RESULTS

A total of 156 subjects were screened, and 153 were randomized: 50, 52, and 51 subjects in the control, short VM, and long VM groups, respectively. The rate of burst suppression was 2.0% (1/50), 30.8% (16/52), and 66.7% (34/51) in the control, short VM, and long VM groups, respectively ( P < 0.001). The long VM group also had lower alpha and beta band power spectral density, and higher permutation entropy compared to the control group. The rate of postoperative delirium was 0.0% (0/48), 0.0% (0/49), and 6.1% (3/49) in the control, short VM, and long VM groups, respectively ( P = 0.107). The long VM group had the highest rate of emergence agitation (64.7% vs 2.0% in the control group and 28.8% in the short VM group, P < 0.001), and the lowest Quality of Recovery-15 scores [106 (100-109) vs 110 (107-118) in the control group and 110 (102-114) in the short VM group, P < 0.001].

CONCLUSION

A VM lasting for >5.2 min per episode resulted in substantial increases in the rates of burst suppression in adult patients undergoing HIFU ablation for liver cancer. Based on these findings, it is recommended that the VM should be limited to ≤5.2 min per episode if possible.