Published papers

Background: In this randomized controlled trial, we examined whether intra- and postoperative infusion of low-dose ketamine decreased postoperative morphine requirement and morphine-related adverse effects as nausea and vomiting after scoliosis surgery. Methods: After IRB approval and informed consent, 36 patients, aged 10-19 years, undergoing posterior correction surgery for adolescent idiopathic scoliosis, were randomly allocated into two groups: intra- and postoperative ketamine infusion at a rate of 2 μg/kg/min until 48 h after surgery (ketamine group, n = 17) or infusion of an equal volume of saline (placebo group, n = 19). All patients were administered total intravenous anesthesia with propofol and remifentanil during surgery and intravenous morphine using a patient-controlled analgesia device after surgery. The primary outcome was cumulative morphine consumption in the initial 48 h after surgery. Pain scores (Numerical Rating Scale, NRS, 0-10), sedation scales, incidence of postoperative nausea and vomiting (PONV), and antiemetic consumption were recorded by nurses blinded to the study protocol for 48 h after surgery. Results: Patient characteristics did not differ between the two groups. Cumulative morphine consumption for 48 h after surgery was significantly lower in the ketamine group compared to the placebo group (0.89 ± 0.08 mg/kg vs. 1.16 ± 0.07 mg/kg, 95% confidence interval for difference between the means, 0.03-0.48 mg/kg, P = 0.019). NRS pain, sedation scales, and incidence of PONV did not differ between the two groups. Antiemetic consumption was significantly smaller in ketamine group. Conclusions: Intra- and postoperative infusion of low-dose ketamine reduced cumulative morphine consumption and antiemetic requirement for 48 h after surgery.

Loss of prolyl hydroxylase 2 (PHD2) activates the hypoxia-inducible factor-dependent hypoxic response, including anaerobic glycolysis, which causes large amounts of lactate to be released from cells into the circulation. We found that Phd2-null mouse embryonic fibroblasts (MEFs) produced more lactate than wild-type MEFs, as expected, whereas systemic inactivation of PHD2 in mice did not cause hyperlacticacidemia. This unexpected observation led us to hypothesize that the hypoxic response activated in the liver enhances the Cori cycle, a lactate-glucose carbon recycling system between muscle and liver, and thereby decreases circulating lactate. Consistent with this hypothesis, blood lactate levels measured after a treadmill or lactate tolerance test were significantly lower in Phd2-liver-specific knockout (Phd2-LKO) mice than in control mice. An in vivo 13C-labeled lactate incorporation assay revealed that the livers of Phd2-LKO mice produce significantly more glucose derived from 13C-labeled lactate than control mice, suggesting that blockade of PHD2 in the liver ameliorates lactic acidosis by activating gluconeogenesis from lactate. Phd2-LKO mice were resistant to lactic acidosis induced by injection of a lethal dose of lactate, displaying a significant elongation of survival. Moreover, oral administration of a PHD inhibitor improved survival in an endotoxin shock mice model. These data suggest that PHD2 is a potentially novel drug target for the treatment of lactic acidosis, which is a serious and often fatal complication observed in some critically ill patients.

BACKGROUND: Neutrophil-derived lipocalin-2 exerts bacteriostatic effects through retardation of iron uptake by the Gram-negative organisms like Escherichia coli. We tested the hypothesis that the expression of lipocalin-2, a bacteriostatic protein, was upregulated by induction of surgical site infection (SSI) with E coli in healthy and diseased rats and that epidural anesthesia modulated its expression. METHODS: Male Wistar rats were randomized into a healthy or disease group, the latter of which was administered lipopolysaccharide. Both groups were further divided into 3 subgroups, the control, saline, and lidocaine groups: group healthy control (n = 10), healthy saline (n = 10), and healthy lidocaine (n = 10) versus group disease control (n = 15), disease saline (n = 18), and disease lidocaine (n = 19), respectively. While saline was epidurally administered to the control and saline groups, lidocaine was administered to the lidocaine groups. Except for the control groups, E coli was injected to the pseudosurgical site to mimic SSI after abdominal surgery. Plasma concentrations of inflammatory cytokine and lipocalin-2 were measured. At 72 hours, the surgical site tissues were obtained to evaluate mRNA expression of lipocalin-2 and E coli DNA expression. RESULTS: All disease subgroups showed markedly increased plasma inflammatory cytokines versus the healthy subgroups. Among the disease subgroups, plasma concentrations of lipocalin-2 and tissue mRNA expression of lipocalin-2 were significantly increased in group disease lidocaine versus the others. Concurrently, E coli DNA expression in the tissue specimens was also significantly lower in group disease lidocaine as compared with group disease saline. CONCLUSIONS: Epidural anesthesia was associated with an increase in the expression lipocalin-2 and a decrease in the expression of E coli DNA at pseudosurgical sites in sick but not healthy rats. These observations suggest a potential mechanism by which epidural anesthesia could reduce the risk of SSI.

Abstract The Hermansky-Pudlak syndrome (HPS) is a rare set of disorders characterized by oculocutaneous albinism, bleeding diathesis, and pulmonary fibrosis, with the latter 2 conditions presenting major challenges in anesthetic management. We report a 53-year-old woman with pulmonary fibrosis secondary to HPS who underwent video-assisted bullectomy to treat recurrent pneumothorax. Preoperative bleeding time and platelet count were within normal limits, but the surgeons had difficulty with continuous oozing from the incision site; the surgical blood loss was 270 mL, which was a relatively large amount for this surgery. Because of her restrictive lung disease, the patient's tidal volume was only 250 mL under pressure-controlled ventilation, with a peak inspiratory pressure of 30 cm H2O and a positive end-expiratory pressure of 5 cm H2O. She also had postoperative respiratory insufficiency, with a partial pressure of arterial CO2 of 112 mm Hg and a pH of 7.08 on arterial blood gas analysis. Then, the patient needed mechanical ventilation for 4 days. In conclusion, patients with HPS require strict respiratory management to support their restrictive pulmonary dysfunction, and, also, we should consider preventive management for hemostasis and adequate analgesia to reduce the patient's work of breathing.

Objectives: The objective of this study was to examine the long-term outcome of percutaneous radiofrequency thermocoagulation (PRT) of the Gasserian ganglion for the 2nd division and multiple division trigeminal neuralgia (TN), compared to the isolated 3rd division TN. Methods: One hundred and forty-eight procedures performed in 89 patients with typical TN between April 2004 and September 2011 in a single pain center were retrospectively analyzed. Baseline characteristics of these patients, immediate outcome, duration pain-free, and complications were obtained from their medical records and questionnaires sent in June 2012. Duration pain-free was assessed by Kaplan-Meier analysis. Results: Of the 148 PRT of the Gasserian ganglion, 37 procedures were performed for isolated 2nd-division TN (V2 TN), 67 procedures were for both 2nd- and 3rd-division TN (V2 + V3 TN), and 38 procedures were for isolated 3rd-division TN (V3 TN). The remaining 6 procedures were performed for V1 + V2 TN and V1 + V2 + V3 TN. Immediate success rates of PRT for V2 TN, V2 + V3 TN, and V3 TN were 100%, 86.6%, and 100%, respectively, whereas the durations pain-free for V2 TN and V2 + V3 TN were significantly shorter than that for V3 TN (9, 12, and 36 months, respectively: P = 0.012). Conclusion: For 2nd-division TN and multiple-division TN, less long-term pain relief after PRT of the Gasserian ganglion can be expected compared with that for isolated trigeminal 3rd-division neuralgia, even if immediate pain relief is achieved.