Effect of different ventilation modes on postoperative cognitive dysfunction in elderly patients undergoing laparoscopic abdominal wall herniorrhaphy.

OBJECTIVE

To compare the effects of three ventilation modes - pressure-controlled ventilation (PC), volume-controlled ventilation (VC), and pressure-regulated volume control ventilation (PRVC) - on postoperative cognitive dysfunction (POCD) in elderly patients undergoing laparoscopic abdominal wall hernia repair.

METHODS

In this prospective study, 485 elderly patients undergoing laparoscopic abdominal wall hernia repair were randomly assigned to one of three ventilation groups: PC, VC, or PRVC. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) at baseline (D0), and on postoperative days 1 (D1) and 3 (D3). Intraoperative physiological indicators, including mean arterial pressure (MAP), heart rate (HR), PaCO2, central venous pressure (CVP), dynamic lung compliance (Cdyn), and optic nerve sheath diameter (ONSD), were recorded at five perioperative time points (T1-T5). Plasma concentrations of brain injury biomarkers (Aβ1-40, S-100β) and inflammatory cytokines (IL-1β, IL-6, TNF-α) were measured at baseline and serial postoperative time points (TI-TV).

RESULTS

The incidence of POCD differed significantly among the three ventilation groups on both postoperative day 1 (P = 0.040) and day 3 (P = 0.034). On day 3, post-hoc analysis revealed that the POCD rate in the PRVC group was significantly lower than in the PC group (P < 0.0167). Regarding potential mechanisms, PRVC was associated with improved dynamic lung compliance and a lower optic nerve sheath diameter compared to both PC and VC groups. Furthermore, PRVC significantly reduced plasma concentrations of the inflammatory cytokines IL-1β and IL-6 (all P < 0.05).

CONCLUSION

In elderly patients undergoing abdominal wall hernia repair, PRVC ventilation reduced the incidence of early POCD, particularly compared to PC ventilation. This neuroprotective effect appears to be linked to improved respiratory mechanics and an attenuated systemic inflammatory response. Therefore, PRVC represents a preferable ventilation strategy for this vulnerable patient population.