Effects of low tidal volume on dynamic arterial elastance in patients undergoing laparoscopic surgery.

Purpose To evaluate the effect of reducing tidal volume from 8 mL/kg predicted body weight (PBW) to 6 mL/kg PBW on dynamic arterial elastance (Eadyn) in patients scheduled for laparoscopic surgery.

Method: After the start of intra-abdominal insufflation, if MAP became < 65 mmHg and SVV > 10%, then the tidal volume was reduced from 8 mL/kg PBW to 6 mL/kg PBW. One min later, 250 mL of lactate Ringer's solution was administered over 10 min. MAP responsiveness was defined as a > 10% increase in MAP following a fluid challenge.

Results: This study included 46 patients, 11 MAP non-responders and 35 MAP responders. Both PPV and SVV decreased significantly (- 19.4 ± 11% and - 19.7 ± 9.9%, respectively) following tidal volume reduction. However, the magnitude of the decrease differed. As a result, the change in Eadyn was minimal on average, although inter-individual variability was observed. Bland-Altman analysis revealed a mean difference of - 0.004, with 95% limits of agreement ranging from - 0.285 to + 0.278. Eadyn values before and after tidal volume reduction failed to predict MAP responsiveness (at 8 mL/kg PBW: area under the ROC curve [AUC] 0.514, at 6 mL/kg PBW: AUC 0.508).

Conclusion: The reduction in tidal volume had a clinically negligible effect on Eadyn. Neither Eadyn values at tidal volume of 8 mL/kg PBW and 6 mL/kg PBW could not predict MAP increase after a fluid challenge during laparoscopic surgery.

Trial registration: This study was registered in the UMIN-CTR Clinical Database (ID: UMIN000054061) on April 4th, 2024. https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi? recptno=R000061722.