Noriko Shimode

The effects of dexmedetomidine and halothane on Fos expression in the spinal dorsal horn using a rat postoperative pain model.

We investigated the effect of an intrathecal injection of a selective alpha2 adrenergic receptor agonist, dexmedetomidine (Dex), and halothane anesthesia on Fos expression in the lumbar spinal dorsal horn after skin incision of the plantar surface of the hind paw, a postoperative pain model using rats. Fos immunoreactivity was induced particularly in the superficial layers of the spinal cord 2 h after surgery. Halothane anesthesia (0.5-1.5%) partially reversed Fos induction, but not in a dose-dependent manner. Preoperative spinal Dex (0.1-10 microg) dose-dependently reduced Fos immunoreactivity, while a relatively high dose of Dex (10 microg) was necessary to produce a profound effect. When used with halothane anesthesia, relatively low doses of Dex (1-3 microg) completely suppressed Fos induction in the superficial spinal layers. These findings indicate that preoperative Dex treatment may provide anesthesia that does not induce stress on spinal neurons.

Propofol in a modified cyclodextrin formulation: first human study of dose-response with emphasis on injection pain.

BACKGROUND:A new lipid-free preparation of propofol has been developed containing the drug, sulfobutylether ß-cyclodextrin and water. The primary objective of this study was to compare the effects of propofol in the lipid formulation with those of the new cyclodextrin formulation, particularly with regard to pain on injection. We hypothesized that the propofol in cyclodextrin would be associated with less pain on injection than propofol in lipid. METHODS:The study was a single-center, double-blind, 2-period, randomized, dose-escalating study using a completely balanced cross-over design in healthy volunteers. Pain on injection was compared between propofol in cyclodextrin and propofol in lipid using subject and observer assessments of pain rated at several different time points. Five response variables to pain were analyzed. RESULTS:Propofol in cyclodextrin had significantly higher pain scores for all 5 variables. Other endpoints, including sedation, showed no difference. CONCLUSION:The propofol in cyclodextrin formulation failed to reduce the pain on injection associated with propofol.

Severe Anaphylaxis after Albumin Infusion in a Patient with Ahaptoglobinemia

WE report a patient who developed severe anaphylactic shock and life-threatening ventricular fibrillation immediately after starting infusion of 5% human plasma protein fractions (Albuminar-5%; ZLB Behring, Tokyo, Japan) during general anesthesia. He was diagnosed postoperatively with ahaptoglobinemia associated with haptoglobin gene deletion. We postulated that this event may have occurred as a result of allergic reaction to a precipitating antibody to haptoglobin associated with use of plasma protein fractions.

Comparison of placental transfer of local anesthetics in perfusates with different pH values in a human cotyledon model

PurposeWe aimed to investigate the placental transfer of local anesthetics in perfusates with different pH values, using a dual-perfused human cotyledon model.MethodsThe dual-perfused human cotyledon model was prepared from placentas obtained following cesarean delivery (n = 5). Protein-free solution was perfused through both maternal and fetal arteries. Four amide-type local anesthetics (mepivacaine [Mep]; lidocaine [Lid]; bupivacaine [Bup]; and ropivacaine [Rop]) were added to the maternal perfusate at 1 µg·ml−1. Three conditions were tested (stage 1, maternal pH 7.4, fetal pH 7.4; stage 2, maternal pH 7.4, fetal pH 6.9; and stage 3, maternal pH 6.9, fetal pH 6.9). Venous blood samples were collected from the fetal circuit after stabilization. The fetal vein/maternal artery concentration ratio (F/M ratio) of the local anesthetics was used as an index of placental transfer. The concentration of human chorionic gonadotropin (hCG) in the maternal vein was measured at the end of each stage.ResultsThe F/M ratios in all stages were in the order of: Mep > Lid > Bup ≒ Rop. The F/M ratios of Mep were significantly higher than those of the other local anesthetics in all stages. The F/M ratios of Lid were higher than those of Rop in stages 2 and 3. The F/M ratios of Lid and Rop were higher in stage 2 than in stage 3. However, the differences between the F/M ratios in the three stages were not as large as expected from the basic uncharged ([B]) condition and pH gap. The concentration of hCG showed a time-dependent decrease with increasing stage (stage 1, 81.0 ± 58.9 mIU·ml−1; stage 2, 57.4 ± 31.8 mIU·ml−1; stage 3, 32.1 ± 19.7 mIU·ml−1).ConclusionOur data clearly show that it is the basic uncharged concentration that mainly determines the placental transfer of amide-type local anesthetics with protein-free perfusate. This finding suggests that Rop and Bup can be used more safely than Mep in terms of placental transfer.

Blood transfusion-induced anaphylaxis and coronary artery spasm during general anesthesia

Anaphylactic reactions to blood transfusion can lead to life-threatening cardiovascular disruptions. We describe a case in which anaphylaxis due to blood transfusion during general anesthesia was the probable cause of coronary artery spasm. Thirty minutes after the transfusion of concentrated red blood cells, the patient’s blood pressure had dropped to 70/40 mmHg and peak airway pressure had increased to 35 cmH2O. The ST segment of the ECG was simultaneously elevated, and the left upper arm became extensively flushed. The tryptase concentration in the patient’s plasma collected 3 h postoperatively was 13.9 μg·l−1 (normal range, 2.1–9.0 μg·l−1). This case report emphasizes that anaphylactic reactions to blood transfusion can potentially lead to coronary artery spasm.