Jun Harada

Serum concentration of lidocaine after transversus abdominis plane block

We measured the serum concentration of lidocaine after transversus abdominis plane (TAP) block with 40 ml of 1% lidocaine in 12 patients under general anesthesia, using a fluorescence polarization immunoassay. The peak mean serum concentration of lidocaine occurred 30 min after the block (3.6 ± 0.7 μg·ml−1). The highest concentration of lidocaine (5.5 μg·ml−1) was recorded 15 min after the block. These results indicate that a TAP block can potentially cause systemic toxicity of a local anesthetic. The analgesic effect of the TAP block may partially depend on the rise in serum concentration of the local anesthetic.

Membrane effects of ropivacaine compared with those of bupivacaine and mepivacaine

We compared the effects of ropivacaine, bupivacaine and mepivacaine on membrane lipids in an attempt to determine the anaesthetic mechanism of ropivacaine with structure‐dependent potency. The membrane effects were determined by measuring anaesthetic‐induced changes in the phase transition temperature and the fluorescence polarization of liposomal membranes prepared with cholesterol and phosphatidylcholine. Bupivacaine, ropivacaine and mepivacaine depressed the membrane lipid phase transition and decreased the polarization of liposomal membranes at 0.0625–1.0u2003mg/mL, indicating that these anaesthetics fluidize membranes at concentrations lower than those in clinical use. Ropivacaine and bupivacaine were effective in fluidizing the membrane core rather than the membrane surface, whereas mepivacaine was a membrane fluidizer acting equally on both regions. In the comparison of membrane fluidization at an equimolar concentration (3.0u2003mmol/L), ropivacaine was found to be less potent than bupivacaine and more potent than mepivacaine. This membrane‐fluidizing potency was also consistent with the hydrophobic properties of these substances evaluated by reversed‐phase chromatography. Structure‐dependent membrane fluidization associating with hydrophobicity appears to underlie the local anaesthetic effect of ropivacaine as well as those of bupivacaine and mepivacaine.

Prolongation of QT Interval Induced by Electroconvulsive Therapy is Attenuated by Landiolol

Objective: The objective of this study was to determine if landiolol, ultra short-acting &bgr; adrenoceptor antagonist, attenuates the prolongation of QT interval caused by electroconvulsive therapy (ECT). Methods: Fifteen patients, scheduled to undergo ECT for the treatment of major depression disorder, were studied. In each patient, 2 sessions of ECT were picked up and randomly assigned to be administered with (treatment L) or without continuous infusion of landiolol (treatment C). Electroconvulsive therapy was administered under general anesthesia with propofol and suxamethonium. Raw electrocardiogram waves were obtained from anesthesia monitor and stored on a personal computer. Automated electrocardiogram analyzing software was used for the determination of QT interval. Results: The increase in corrected QT caused by suxamethonium was significantly smaller in treatment L (36.8 ± 14.5 ms for treatment C vs 17.9 ± 6.5 ms for treatment L; P < 0.001). The increase in corrected QT caused by ECT was also smaller in treatment L (72.3 ± 23.1 ms for treatment C vs 54.6 ± 17.9 ms for treatment L; P = 0.02). Conclusions: The prolongation of QT interval caused by SUX and ECT was partially attenuated by landiolol.

Prophylactic effects of pirenzepine (M1-blocker) on intraoperative stress ulcer : comparison with an H2-blocker

Patients under general anesthesia were treated with either an H2-blocker, ranitidine 50 mg, or an M1-blocker, pirenzepine 10 mg, and the effects of the two drugs on the gastric mucosa were compared by the measurement of the gastric juice pH and viscosity. The results showed that pirenzepine increased the gastric juice pH sufficiently while maintaining the gastric juice viscosity, and that ranitidine maintained the gastric juice pH higher than pirenzepine while decreasing the gastric juice viscosity. These results suggest that treatment with pirenzepine may have advantages in the prevention of stress ulcers.

The effect of sevoflurane on developing A/J strain mouse embryos using a whole-embryo culture system—the incidence of cleft lip in culture embryos

A/J strain mice have a high spontaneous incidence of cleft lip (ICL) and/or palate. The primary palate-related effects of sevoflurane on developing A/J strain mouse embryos (embryos) were studied using a whole-embryo culture (WEC) system. This system could separate the direct effects of sevoflurane from those that are maternally mediated. A total of 205 10.5-d embryos were cultured for 24xa0h in either a control group (control gas: 95% O2 and 5% CO2) or sevoflurane-administered groups (1/4, 1/2, and 1 minimum alveolar concentration (MAC) with control gas) for 8xa0h. After 16xa0h, 11.5-d culture embryos were examined in terms of crown-rump length, number of somites, and protein content. Crown-rump length in the 1 MAC was significantly shorter than in the control group (pu2009<u20090.05). Protein content in the 1/2 MAC (pu2009<u20090.05) and 1 MAC (pu2009<u20090.001) was significantly lower than in the control group. The ICL showed no significant differences between each group. (The ICL rose with an increase in the sevoflurane concentration, but this was not significant). The positive findings in this study indicate that a WEC system is useful for studying the mechanisms of ICL (teratogenicity) associated with sevoflurane.

General Anesthetic Management of a Patient With Hypertrophic Cardiomyopathy for Oral Surgery: Did Digitalis Contribute to Bradycardia?

Stabilization of circulatory dynamics is a critical issue in the anesthetic management of patients with hypertrophic cardiomyopathy (HCM). In this report, we managed general anesthesia for a 74-year-old male patient with nonobstructive HCM who developed circulatory instability intraoperatively. Severe bradycardia measuring 35 beats/min and hypotension measuring 78 mm Hg systolic were observed during surgery. Using stroke volume variation and stroke volume from the FloTrac as indices, successful circulatory management was performed with dopamine. The hypotension and bradycardia were thought to be the result of methyldigoxin and possibly associated with our perioperative management. Cardiology consult should have been obtained. We demonstrated that the FloTrac can be beneficial in diagnosing and managing cardiovascular instability and administration of dopamine in the anesthetic management of nonobstructive HCM patients.

A Case of Atypical Postoperative Malignant Hyperthermia after the Eighth General Anesthesia in a Child with Cheilognathopalatoschisis

Background and Objectives: Postoperative malignant hyperthermia (MH) occurs after discontinuation of volatile anesthetics or in the early postoperative period after general anesthesia. We experienced a case of atypical postoperative MH identified by dark reddish-brown urine produced 40 min after the end of eighth general anesthesia in an 11-year-old male with cheilognathopalatoschisis. Case Report: Anesthesia was induced using thiamylal, fentanyl citrate, remifentanil, rocuronium, and maintained with sevoflurane, fentanyl citrate, remifentanil. The patient was observed clenching his teeth, tachycardia, profuse perspiration, shivering-like motion, and hyperpnoea from the end of the operation to return to the HCU ward, whereas the maximum of axillary temperature was 37.9°C. Although these abnormal symptoms and vital signs were disappeared, abnormally high level of CK, AST, ALT, LDH, ALP, and myoglobinuria were recognized. We decided to not administer dantrolene hydrate because his vital signs and daily activity were restored to those observed preoperatively. However, the patient was continued infusion therapy for 9 days after the operation until the blood and urine test values returned to the preoperative ones. Conclusions: We experienced atypical postoperative MH identified by dark reddish-brown urine 40 min after the end of eighth general anesthesia. We decided not to administer dantrolene hydrate because his vital signs and daily activity were restored to those observed preoperatively when we recognized abnormally high level of CK, AST, ALT, LDH, ALP, and myoglobinuria. Consequently, rhabdomyolysis continued and in 9 days, the abnormally high values of CK, AST, ALT, LDH, and ALP recovered to the reference value.

An example of facilities for intraoperative radiotherapy

Intraoperative radiotherapy (IORT) is now accepted in many institutions! as one of the radiotherapies for cancer. This treatment has several advantages over conventional radiotherapies, but offers anesthesiologist some problems., In Fukui Medical School Hospital, a new IORT unit designed by the suggestion of anesthesiologists was opened on January, 1987. Between then and the end of 1989, 29 patients have received IORT. We describe the anesthetic management of these 29 patients who underwent IORT in this IORT unit.

A consideration on the new classification of latest lung ventilators.

Concerning the classification of ventilators, Elam (1958), Fairley (1959), and Hunter (1961) reported some simple ones such as pressure limited, volume limited, pressure preset, or volume preset models. Mapleson (1969) also classified them by the generating force or cycling together with the above-mentioned types.The latest ventilators applicable to patients with respiratory failure usually have some cut-off function at high airway pressures as a safety measure. Therefore, all of them belong to the pressure limited type. Some ventilators are of two types such as the time cycled and pressure cycled type.Therefore, we attempted to classify ventilators into four groups, i.e. the time cycled, volume cycled, pressure cycled and selective time-pressure cycled types according to the fundamental mode of ventilator function, the so-called change of cycling from inspiration to expiration. Each group was further divided into subgroups according to preset dials such as respiratory rate, liE ratio, inspiration time, expiration time, tidal volume, flow rate and airway pressure.By this method, fifty one ventilators on the market in Japan can be classified without overlapping. Although this clssification seems complex, it will be of use in selecting ventilators by emphasizing preset dials according to the user’s needs, ability or both.