Comparison of Robot-assisted Versus Conventional Laparoscope on Incidence and Risk Factors of Postoperative Delirium for Patients undergoing radical prostatectomy: A single-center Retrospective Analysis

Background: Robot-assisted laparoscopic radical prostatectomy ( RALRP) has better effects than conventional laparoscopic radical prostatectomy (LRP). However, there were few research focus on the incidence and risk factors of postoperative delirium for patients with different procedures. Methods: Eighty-one cases of RLRP patients (group RALRP) and 71 cases of LRP patients (group LRP) under general anesthesia were collected from anesthesia information system from June 2013 to December 2019. Comparison of the time of preparation period before surgery(Tp), time of operation(To), time of anesthesia maintenance (Ta), time of anesthesia recovery(time from cessation of intravenous anesthetic to endotracheal extubation, Tr), time of endotracheal extubation(time from endotracheal extubation to discharge from post-anesthesia care unit, Te), dosage of anesthetic (propofol, sufentanil, remifentanil), PaCO2, plasma lactate level and airway pressure at different points (before pneumoperitoneum, post-pneumoperitoneum, after loosening pneumoperitoneum), the incidences of postoperative delirium and utilization of mannitol, IAP, dosage of vasoactive agents(ephedrine, methoxamine and atropine), fluid infusion volume, blood transfusion volume, blood loss, postoperative hospitalization time (Th) and overall cost. Results: The incidences of postoperative delirium and utilization of mannitol in group RALRP and LRP were (17.3% VS 32.4%, P=0.03;7.4% VS 21.1%, P=0.014), Tr was (31.52±9.89 VS 38.65±16.32 min; P=0.01,95%CI 2.72-11.54), IAP was (12.72±1.87 VS 13.37±1.12 mmHg; P=0.01, 95%CI 0.16-1.14), PaCO2 at post-pneumoperitoneum and after loosening pneumoperitoneum were (47.89±10.89 VS 38.65±16.32 mmHg; P <0.001, 95%CI 6.47-11.98; 40.77±5.34 VS 43.57±4.54 mmHg; P=0.001, 95%CI 1.17-4.37), the difference was statistically significant. Tp, To, Ta and overall cost of patients in the RLRP group were significantly longer than those in the LRP group (P <0.02). No statistical difference was found in other observation variables. The incidence of postoperative delirium was considered as the dependent variable for binary logistic regression analysis. The result showed the incidence of postoperative delirium increased 1.17 times (95%CI 1.06-1.17), 1.13 times (95%CI 1.03-1.24), and 1.66 times (95%CI 1.02-2.70) for each unit increase in Tr, post-pneumoperitoneum PaCO2 and IAP.Conclusion: Compared with group LRP, patients in group RALRP had lower IAP, lower incidence of postoperative delirium and shorter recovery time, but the overall cost was higher. IAP is the main factor affecting the incidence of postoperative delirium.