The influence of different setting of respiratory parameters during operation on the postoperative cognitive function after laparoscopic radical prostatectomy

Abstract

Objective To investigate the influence of different respiratory parameter settingduring laparoscopic radical prostatectomy on early postoperative cognitive function. Methods One hundred patients aged 65-75 years undergoing laparoscopic radical prostatectomy were randomly divided into 5 groups(n=20): group A, B, C, D and E. All patients were ventilated with identical minute volume(MV) 100 ml/kg though with respective respiratory rate(RR) of 8, 10, 12, 14 and 16 bpm respectively. Patients in five groups were all graded by the mini-mental state examination(MMSE) at time points of 1 day before operation(T0), postoperative 6 h(T1) postoperative 6 h(T2), 24 h(T3), 48 h(T4),72 h(T5),7 d(T6). The serum S100β concentation was detected at T0, T1, T2 and T3. Partial pressure of carbon dioxide(PaCO2) in arterial blood was tested before pneumoperitoneum(Ta) and immediately after pneumoperitoneum(Tb). Results PaCO2 in group D at Tb (42.8±3.2) mmHg(1 mmHg=0.133 kPa) was lower than the other groups(P<0.05). The MMSE scores in group D at T2-T3(26.90±0.60,27.80±0.62), were remarkably higher than those in other groups(P<0.05). The serum S100β protein concentrations in each group at T2-T3 were significantly higher than that at T0(P<0.05). The serum S100β protein concentrations in group D at T2 and T3 [(330±25) mg/L and (300±26) mg/L], were dramatically lower than that in other groups(P<0.05). Conclusions Early postoperative cognitive function can be improved by regulating intraoperative respiratory parameters properly during laparoscopic radical prostatectomy. The respiratory parameter of MV 100 ml/kg combined with RR 14 bpm may be more reasonable for this type of surgery. Key words: Respiratory parameter; Postoperative cognitive function; Laparoscopic; Radical prostatectomy