Effects Of High Or Low Hypercapnia On Brain Function In Elderly Patients With Laparoscopic Surgery

Objective By observing the changes of elderly patients cerebraloxygen metabolism and postoperative cognitive function undergoinglaparoscopic surgery at different levels of PaCO2, explore the effects ofelderly patients brain function in different levels of PaCO2underartificial pneumoperitoneum.Methods Choose elective laparoscopic abdominal surgery,40patients, ASA Ⅰ～II. The operation time is greater than3hours. Byrandomly divided into two groups(n=20): hypocapnia group (groupL)PaCO225~35mmHg, normal control group(group N)PaCO225~35mmHg, Also collected intraoperative uncorrectable hypercapniagroup (group P),15cases. The patients of group N and group L weretracheal intubated after anesthesia induction and mechanicallyventilated．Intraoperative adjusted respiratory parameters according to theconcentration of PaCO2in order to maintain it at the target level. MAP,HR, radial artery, internal jugular vein bulb venous blood gas analysiswere monitored at T0before operation, after induction10min (T1),Target PaCO2stabilized after gas injection60min (T2),120min（T3）,180min（T4）and awake after extubation10min (T5). Calculated SjvO2, Da-jvO2,CERO2according to the formula. Assessed MMSE score andpostoperative pain VAS score in the point of preoperative (T6), after24h(T7),48h (T8),72h (T9) and the incidence of POCD.Results Three groups of patients compared to general information,intake and output perianesthesia, operative time, recovery time and theamount of anesthetic were not statistically significant.Compared with T0, the HR, MAP of group P increased, PaCO2increased significantly and pH decreased at T2～T5. Group L is theopposite at T2~T4. The HR, pH of group N decreased and PaCO2increased significantly. Three groups of patients PaO2increasedsignificantly. Compared with the N group, the HR, MAP of group Pincreased, pH decreased and PaCO2increased significantly. Group L isthe opposite at T2~T4.The changes of three groups of patients SjvO2, Da-jvO2, CERO2:Compared with T0, The SjvO2of group P and group N were significantlyincreased at T1～T4, Da-jvO2, CERO2decreased. The SjvO2of group Lwere increased and Da-jvO2, CERO2decreased at T1. Compared with theN group, the SjvO2of group P were increased and Da-jvO2, CERO2decreased significantly at T2~T4.Group L is the opposite at T2~T4.The changes of three groups of patients MMSE score: Comparedwith T6，the MMSE score of three groups of patients were significantlydecreased at T7, T8. Compared with the N group: The MMSE score ofgroup P decreased, the incidence of POCD increased. Conclusion Hypercapnia group existed cerebral oxygen supplyand demand imbalance, the incidence of POCD has a higher rate, braintissue hypoxia may exist. Hypocapnia group and normal control groupwere able to maintain a good balance of cerebral oxygen supply anddemand.