3. Postoperative cognitive dysfunction after urologic surgery. Diagnostic role of cerebral oximetry technique and plasma concentration of NMDA receptor antibodies

C. Bodolea¹, Ana Oblezniuc², Ana Maria Caea², Narcisa Botos¹, F. Tamasy¹, T. Cristea², B. Feciche², Z. Mihaly2, I. Coman¹,V. Donca¹ S. Pintea³

1 Universitatea de Medicină şi Farmacie „Iuliu Haţieganu” Cluj-Napoca
2 Spitalul Clinic Municipal Cluj-Napoca
3 Universitatea „Babeş-Bolyai” Cluj-Napoca

Abstract

Background: Postoperative cognitive dysfunction (POCD) in the elderly patients is an unwanted, most of the time underestimated and relatively frequent complication of the postoperative period. POCD is only detectable through the usage of neuropsychological tests and it is, probable, the consequence of a brain neuroinflammatory process. The use of near infrared spectroscopy (NIRS) technologies for cerebral saturations monitoring, can decrease the incidence of POCD, the adverse outcomes and length of hospital stay in general and cardiac surgery patients. High plasma concentration of N-methyl D-aspartate (NMDA) receptor antibodies (NR2Ab) has been proven highly predictable for occurrence of the postoperative neuro­logical events in cardiac surgery.

The aim of the study was to evaluate the importance of the individual risk factors, the intra and postoperative episodes of cerebral desaturation (by NIRS) and the cerebral ischemia (quantified by detection of high plasma con­centration of NMDA receptor antibodies-NR2Ab) in the development of POCD.

Materials and methods: Prospective, randomized ethically approved and consented study enrolled 55 ASA I-III patients, aged over 65. 30 patients were scheduled for urologic sur­gery (group S) and have been compared with 25 nonsurgical subjects (group NS). Group S was divided in two subgroups: 16 patients with cerebral oximetry monitoring 24 hours from the beginning of the surgical procedure (group SX) and 14 patients with standard monitoring but without cerebral oximetry (group SNX).The NS group was also divided in two subgroups: 15 in-hospital patients, with medical diseases (group NSH) and 10 control not-hospitalised elderly (group NSNH). Neuropsychological tests have been applied in all patients preoperatively (group S) or as a primary evaluation (group NS) and, subsequently, at 10 days, 1, 3 and 12 months postoperative or post pri­mary evaluation. Regional oxygen saturation (rSO2) monitoring for patients belonging to SX group was continuously monitored using near-infrared spectro­scopy (INVOS 4100; Somanetics Inc, USA) during the surgery and first 24 hours postoperatively. Plasma levels of NR2Ab (assessed with ELISA-test according to producer) were recorded 24 hours preoperatively and at one month postoperatively.

Results: Compared with the NS group, the incidence of POCD in group S was significantly higher (p < 0.001) at 10 days and 1 month postoperatively but not at 3 and 12 months. There were no differences in POCD incidence at any time, while comparing any other groups, including SX group compared with SNX group and NSNH group compared with NSH group. Regarding the NR2Ab plasma levels, at 1 month postoperatively there were no differences between the POCD patients of group S when compared with the patients of group NS (1.78 ± 0,63 vs 1.6 ± 0,45 ng/dL).

Conclusion: In a pilot study, POCD after urologic surgery has a maximum incidence in the first month postoperatively regardless the use of cerebral oximetry monitoring and without significant increase of NR2Ab plasma levels, making improbable a cerebral ischemic ethiology.

Keywords: postoperative cognitive dysfunction, cerebral oximetry, NMDA receptor antibodies

J Rom Anest Terap Int 2011; 18: 11-18

Disfuncţia cognitivă postoperatorie după chirurgia urologică majoră. Rolul diagnostic al oximetriei cerebrale şi al autoanticorpilor antifragment 2A de receptor NMDA (N­metil-D-aspartat)