The effect of Trendelenburg position and pneumoperitoneum on regional cerebral oxygen saturation during gynecological laparoscopic surgery

BACKGROUND: The Trendelenburg positon and pneumoperitoneum for gynecological laparoscopic surgery can affect cerebral oxygenation through the change of cerebral blood flow. The aim of this study was to evaluate the effect of pneumoperitoneum in a 20degrees Trendelenburg position on regional cerebral oxygen saturation (rSO2). METHODS: Thirty-three female patients of American Society of Anesthesiologists I and II physical status who were undergoing gynecological laparoscopic surgery were enrolled. The rSO2 was monitored with near-infrared spectroscopy (INVOS 5100, Somanetics, Troy, USA). The rSO2, the rate of change in the rSO2, the mean arterial pressure (MAP), heart rate (HR), arterial partial pressure of CO2 (PaCO2) and O2 (PaO2) and end-tidal CO2 (ETCO2) were measured at the following times: immediately before the pneumoperitoneum and when placing the patient in the Trendelenburg position (T0), 5, 10, 15 and 20 min after pneumoperitoneum and position change (T1, T2, T3 and T4). RESULTS: Both the right and the left rSO2 increased significantly during pneumoperitoneum in a Trendelenburg position compared with the value at T0 (from T1 to T4) (P < 0.01). The MAP and PaCO2 also increased significantly (P < 0.01). CONCLUSIONS: During the gynecologiccal laproscopioc surgery, cerebral oxygenation, as assessed by rSO2, increased even though the Trendelenburg position and pneumoperitoneum could increase MAP, intracranial pressure and PaCO2, which is considered to be maintained by cerebral autoregulation.

Effect of flumazenil on recovery from anesthesia and the bispectral index after sevoflurane/fentanyl general anesthesia in unpremedicated patients / 대한마취과학회지

BACKGROUND: Benzodiazepines have a hypnotic/sedative effect through the inhibitory action of gamma-aminobutyric acid type A receptor. Flumazenil antagonizes these effects via competitive inhibition, so it has been used to reverse the effect of benzodiazepines. Recently, flumazenil has been reported to expedite recovery from propofol/remifentanil and sevoflurane/remifentanil anesthesia without benzodiazepines. Endogenous benzodiazepine ligands (endozepines) were isolated in several tissues of individuals who had not received benzodiazepines. METHODS: Forty-five healthy unpremedicated patients were randomly allocated to either flumazenil or a control groups. Each patient received either a single dose of 0.3 mg of flumazenil (n = 24) or placebo (n = 21). After drug administration, various recovery parameters and bispectral index (BIS) values in the flumazenil and control groups were compared. RESULTS: Mean time to spontaneous respiration, eye opening on verbal command, hand squeezing on verbal command, extubation and time to date of birth recollection were significantly shorter in the flumazenil group than in the control group (P = 0.004, 0.007, 0.005, 0.042, and 0.016, respectively). The BIS value was significantly higher in flumazenil group than in the control group beginning 6 min after flumazenil administration. CONCLUSIONS: Administration of a single dose of 0.3 mg of flumazenil to healthy, unpremedicated patients at the end of sevoflurane/fentanyl anesthesia without benzodiazepines resulted in earlier emergence from anesthesia and an increase in the BIS value. This may indicate that flumazenil could have an antagonistic effect on sevoflurane or an analeptic effect through endozepine-dependent mechanisms.

Plasma Concentrations of Morphine during Postoperative Pain Control

BACKGROUND: Morphine has been commonly used for postoperative pain control. We measured plasma concentrations of morphine and compared the efficacy and safety of continuous epidural analgesia (CEA) using morphine-bupivacaine with intravenous patient controlled analgesia (IV-PCA) with morphine for 48 hrs after the end of the operation. METHODS: Nineteen patients undergoing Mile's operation were assigned to receive a morphine loading dose of 5 mg followed by IV-PCA with 0.1% morphine (IV-PCA group, n = 9) or a morphine loading dose of 2 mg and 0.125% bupivacaine 10 ml, followed by CEA with 0.004% morphine and 0.075% bupivacaine at a rate of 5 ml/hr (CEA group, n = 10). The plasma concentrations of morphine were measured and visual analog scales (VAS) for pain were recorded at 1, 6, 12, 24, and 48 hr postoperatively and the effects on respiration and any other side effects were noted. RESULTS: The mean maximal and minimal levels of plasma morphine were 40.2 +/- 21.2 ng/ml and 23.4 +/- 9.7 ng/ml for the IV-PCA group and 11.8 +/- 3.5 ng/ml and 8.2 +/- 1.9 ng/ml for the CEA group, respectively. Resting and dynamic pain scores were significantly lower in the CEA group than in the IV-PCA group. There were no significant differences for the effects on respiration and for any side effects between the two groups. CONCLUSIONS: We evaluated plasma concentrations of morphine with CEA using morphine-bupivacaine and IV-PCA using morphine for the postoperative pain control. The CEA group had better postoperative analgesia than that of the IV-PCA group and the incidence of side effects were not significantly different between the two groups.