Elimination pharmacokinetics of sevoflurane and desflurane during the recovery phase of anesthesia

BACKGROUND: Sevoflurane and desflurane are widely used anesthetics and can be simulated in pharmacokinetic models. These models are related to steady state pharmacokinetics, As anesthetic elimination is a non-steady state process, we evaluated the elimination data of volatile anesthetics using a two-compartment model (bi-exponential function). 50, 80, and 90% context-sensitive decrement times were evaluated with this function. These times are related to awakening and cognitive function recovery. METHODS: Forty-eight healthy patients were enrolled for minimal surgery under general anesthesia. They were randomly anesthetized with either sevoflurane or desflurane. At the end of surgery, when the administration of the volatile anesthetics was discontinued, end-tidal concentrations (PE) were recorded for 15 minutes. We calculated and analyzed the fraction of anesthetic concentrations (PE/PE0) using a bi-exponential function (PE0: the last end-tidal concentration of anesthetics during anesthesia). RESULTS: A bi-exponential function was fit to the elimination data using non-linear mixed-effect modeling. It showed that the anesthetic duration had effects on the coefficients of early and late components and not on the log rate constants. The coefficient of late components increased and the coefficient of early components decreased with prolonged anesthetic duration. Irrespective to the type of anesthetics, prolonged anesthesia did not affect the context-sensitive half-life; however, a prolonged period of time was required to reach 80 and 90% decrement after prolonged anesthesia. CONCLUSIONS: Prolonged anesthetic duration slowed down the elimination of volatile anesthetics. It delayed awakeness and a return to normal cognitive function after anesthesia.

Long-Term Effect of Loxoprofen Sodium on Nocturia in Patients with Benign Prostatic Hyperplasia

PURPOSE: We evaluated the long-term effects of loxoprofen on nocturia in patients with benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: Between January 2006 and December 2008, 40 BPH patients with 2 or more episodes of nocturia received an alpha-blocker, 5-alpha reductase inhibitor, and a single dose of 60 mg of loxoprofen at night before sleep for 12 months (Group I). During the same period, 38 BPH patients selected as the control group received an alpha-blocker and 5-alpha reductase inhibitor (Group II). Patients were reevaluated after 3, 6, and 12 months of treatment by the number of nocturia episodes and side effects. RESULTS: After 3 months of treatment, the number of nocturia episodes decreased significantly compared with baseline in both group I and group II (1.9+/-0.7, 2.1+/-0.7, respectively, p0.05). After 6 and 12 months of treatment in group I, treatment-emergent adverse events, including 5 cases of gastric discomfort (12.5%), 3 cases of leg edema (7.5%), and 1 case of decreased urine volume (2.5%), occurred in 9 of the 40 (22.5%) patients. CONCLUSIONS: Loxoprofen can be an effective treatment for patients with nocturia secondary to BPH in the short term. Long-term use of loxoprofen is not recommended because of the side effects.

Expression of Claudin-1 and -7 in Clear Cell Renal Cell Carcinoma and Its Clinical Significance

PURPOSE: We investigated the correlations between the expression of claudin-1 and claudin-7 in clear cell renal cell carcinoma (clear cell RCC) and clinical parameters. MATERIALS AND METHODS: The subjects of this study were 119 patients with confirmed clear cell RCC between January 2000 and December 2007. Their RCC tissues were immunohistochemically stained for claudin-1 and claudin-7. The correlations between the expression of claudin and parameters such as sex, age, body mass index (BMI), tumor size, TNM stage, Furhman nuclear grade, postoperative distant metastasis, and cancer-specific survival were analyzed. RESULTS: Among the total 119 subjects, claudin-1 was expressed in 18 (15.1%) and claudin- 7 in 31 (26.1%). Claudin-1 was expressed in patients who were older (p=0.007), who had a greater tumor size (p=0.001), who had a higher pathologic T stage (p=0.009), who had preoperative distant metastasis (p=0.035), and who had a higher Furhman nuclear grade (p=0.004). Claudin-7 was expressed only in patients who had a higher Furhman nuclear grade (p=0.031). The risk of postoperative distant metastasis was associated with the expression of claudin-1 (p0.05). CONCLUSIONS: In clear cell RCC, claudin-1 was expressed in patients who were older and who had a greater tumor size, who had higher T or M stages, and who had a higher Furhman nuclear grade. The expression of claudin-1 was associated with a higher risk of postoperative distant metastasis.

Analysis of factors related to patient refusal of spinal anesthesia / 대한마취과학회지

BACKGROUND: Spinal anesthesia is a anesthetic technique that can be easily used and practically applied according to patient's preference and physiologic status, surgical procedures and so forth. The purpose of the present study is to analyze factors related to patient refusal of spinal anesthesia, arising from the previous spinal anesthesia experience associated with side effects or unsatisfactory senses after spinal anesthesia. METHODS: One hundred ninety four patients undergoing various surgical procedures under spinal anesthesia were enrolled. We made a questionnaire that consisted of examination items and question items, and checked it during spinal anesthesia and about 24 hours after spinal anesthesia. Factors related to patient refusal of spinal anesthesia were analyzed with multiple logistic regression. RESULTS: Thirty one out of 194 patients (16%) rejected to receive spinal anesthesia if they would have chance to have it again. Significant factors associated with refusal of spinal anesthesia were low back pain (P = 0.005), needle type (Quincke) (P = 0.025) and tingling sensation in the lower extremities immediately after spinal anesthesia induction (P = 0.003). Low back pain was significantly associated with the number of attempts of spinal block (P = 0.023). CONCLUSIONS: Factors related to patient refusal of spinal anesthesia are low back pain, needle type and tingling sensation. Low back pain is related to the number of attempts of spinal block. Practitioners should give patients appropriate information about spinal anesthesia preoperatively and consider using Whitacre needle and avoid multiple attempts of spinal block so as to increase patient's compliance with spinal anesthesia.

Response of cerebral oximetry to increase in alveolar concentration of desflurane: effect of remifentanil and cerebrovascular CO2 reactivity / 대한마취과학회지

BACKGROUND: It is known that sympathetic stimulation and increase in cerebral blood flow velocity can be induced by desflurane. Cerebral oxygen balance could be disturbed during desflurane induction. Aim of this study was to elucidate that cerebral oxygen imbalance induced by desflurane mask induction can be reduced by combination of remifentanil and hypocapnia. METHODS: Twenty ASA 1-2 subjects were allocated randomly into 5 groups divided by concentration of remifentanil (0.0, 0.5, 1.0, 1.5, and 2.0 ng/ml). After confirmation of attaining proposed concentration of remifentanil, propofol and vecuronium were administered and mechanical ventilation was done with 8% desflurane with facial mask. Subsequently, changes in regional cerebral oxygen saturation (DeltarSO2), arterial blood pressure, heart rate, cardiac index, estimated alveolar concentration of desflurane (PDESF), and end-tidal concentration of carbon dioxide (PETCO2) were recorded for the following 10 minutes. According to concentration of desflurane and remifentanil, DeltarSO2 and hemodynamic factors were checked. RESULTS: During desflurane induction, changes in cerebral oximetry reached up to +10% (6 [first quartile], 13 [third quartile]). Arterial blood pressure, heart rate, and cardiac index were changed within clinical ranges. The DeltarSO2 showed S-shaped increasing pattern according to increasing PDESF. Hypocapnia and concentration of remifentanil reduced the maximum DeltarSO2 (P = 0.0046, P = 0.0060). Hypocapnia also shifted the curve to left (P = 0.0001). CONCLUSIONS: During 8% desflurane induction, regional cerebral oxygen saturation (rSO2) increases maximum +25%. Hypocapnia and use of remifentanil can reduce the increase in regional cerebral oxygen saturation.

Pulmonary edema during hysteroscopic surgery: Three cases report / 대한마취과학회지

Hysteroscopic surgery has become a routine gynecologic procedure. The advantages are associated with more accurate removal of lesion, its short operating time, rapid post-operative recovery and low morbidity. However, there are potentially serious complications which can be occured during and following hysteroscopic surgery. The complications are uterine perforation, fluid overload and electrolyte disturbance due to intravasation and absorption of uterine distention media, hemorrhage and, rarely, gas or air embolism. We experienced pulmonary edema during hysteroscopic surgery in three consecutive patients. Therefore, we report these cases of fluid overload with uterine distention media resulting acute pulmonary edema during hysteroscopic surgery.

Effect-site concentration of remifentanil for smooth tracheal intubation without muscle relaxants provokes hypotension under desflurane anesthesia / 대한마취과학회지

BACKGROUND: Many reports with hypnotics and opiates have been published for nonrelaxant tracheal intubation.In addition to its immediate onset and short duration time, remifentanil can well prevent responses against short and strong stimulation like tracheal intubation.However, the high concentration of remifentanil for nonrelaxant tracheal intubation can cause hemodynamic instability, thus we tried to estimate the predicted effect-site concentration of remifentanil for smooth intubation and provoking hypotension. METHODS: Forty three ASA I and II patients were randomly selected to receive an effect-site-controlled infusion of remifentanil 0, 2, 4, 6 ng/ml and propofol 2 mg/kg.Trachea was intubated after 3 minutes of manual breathing support with desflurane 6 vol%. The vital signs, end-tidal concentration of desflurane and responses of patients were recorded before intubation for 3 minutes and until 2 minutes after intubation every minute.The effective effect-site concentration (ECe) was calculated at 95% successful rate of smooth intubation and at 50% of provoking hypotension (equal to or under 55 mmHg). RESULTS: The estimation results of the logistic regression stated that 95% ECe of remifentanil for smooth intubation was 8.0 (5.0-14.3) ng/ml and 50% ECe for provoking hypotension equal to or under 55 mmHg before intubation was 5.0 (2.6-9.7) ng/ml. CONCLUSIONS: Remifentanil at 8.0 ng/ml provided good conditions for smooth intubation without muscle relaxants but could provoked hypotension.Consequently, we recommend the careful observation of the blood pressure with the use of remifentanil and the evaluation of the suitable measures to maintain the blood pressure for nonrelaxant tracheal intubation.

Discrimination of hemoglobin-effects on arterial-to-jugular bulb oxygen content differences according to arterial carbon dioxide tension

BACKGROUND: Arterial jugular bulb oxygen content differences (AJVDO2) can be related to cerebral blood flow and oxygen consumption. Plasma Hb has been reported to have both-sided effect on AJVDO2. Increased Hb increases oxygen content in artery and jugular bulb, and the net effect is to reduce AJVDO2. Moreover, increasing Hb raises blood viscosity, and could increase AJVDO2. This study was designed to discriminate the Hb-effects on AJVDO2 mathematically. METHODS: Sixty adults were enrolled in this study. General anesthesia and mechanical ventilation were administered. A normocapnic and a subsequent hypocapnic state were achieved. Paired data including 1/AJVDO2, PaCO2, Hb, mean arterial pressure, temperature and anesthetic concentration were recorded during each state. Nonlinear mixed-effects model was applied to fit 1/AJVDO2 using PaCO2 and Hb as covariates. RESULTS: The 1/AJVDO2 was well modeled by PaCO2 and Hb using a three-parameter logistic function: predicted 1/AJv DO2 = 0.38713 / 1+e(31.20981-PaCO2)/25.94210-1.45162xHb The increase in PaCO2 raised the 1/AJVDO2 sigmoidally (P < 0.0001) and its slope was affected by Hb (P = 0.0022). The transition point of the Hb-effect was PaCO2 = 31.20981 (SEM 1.519201). Intraclass correlation coefficient was estimated at 0.9973. CONCLUSIONS: Our finding suggests that the Hb-effect on 1/AJVDO2 is both-sided; the viscosity-effect is dominant at low levels of PaCO2 and effect of oxygen content is dominant at high levels of PaCO2