Radiation exposure to anaesthetists during endovascular procedures.

Medical radiation exposure increases the likelihood of cataract formation. A personal dosimeter was attached to the left temple of 77 anaesthetists during 45 endovascular aortic aneurysm repairs and 32 interventional neuroradiology procedures. Compared with interventional neuroradiology, the median (IQR [range]) total radiation dose emitted by fluoroscopic equipment was significantly lower during endovascular aortic aneurysm repair (4175 (3127-5091 [644-9761]) mGy than interventional neuroradiology (1420 (613-2424 [165-10,840]) mGy, p < 0.001). However, radiation exposure to the anaesthetist's temple was significantly greater during endovascular aortic aneurysm repair (15 (6-41 [1-109]) µSv) than interventional neuroradiology (4 (2-8 [0-67]) µSv, p < 0.001). These data suggest that anaesthetists at our institution would have to deliver anaesthesia for ~1300 endovascular aortic aneurysm repairs and ~5000 interventional neuroradiology cases annually to exceed the general occupational limits, and ~10,000 endovascular aortic aneurysm repairs and ~37,500 interventional neuroradiology cases to exceed the ocular exposure limits recommended by the International Commission on Radiological Protection. Nevertheless, anaesthetists should be aware of the risk of ocular radiation exposure, and reduce this by limiting the time of exposure, increasing the distance from the source of radiation, and shielding.

In situ synthesis of Au-shelled Ag nanoparticles on PDMS for flexible, long-life, and broad spectrum-sensitive SERS substrates.

A simple and fast one-step fabrication method of silver nanoparticles (AgNPs) on a polydimethylsiloxane (PDMS) film and their improvement as highly sensitive surface enhanced Raman scattering (SERS) substrates via atomically thin Au coatings is demonstrated. The thin Au layer provides oxidation resistivity while maintaining the broad spectral range SERS sensitivity of Ag nanoparticles.

Electroencephalographic responses to the formalin test in rats.

The formalin test is an animal model of persistent pain. Although biphasic behavioral responses to formalin injection have been well described, the significance of the biphasic time course of the pain behaviors has not been established. To explore the significance of the behavioral responses to the formalin injection, we measured and analyzed cortical electroencephalogram (EEG) during the formalin tests in rats. Formalin was injected subcutaneously in the hindpaw of freely moving rats, and behavioral responses were visually counted and recorded. Results were compared with a control group which received saline injection. Neocortical EEG was recorded from implanted dural surface electrodes and analyzed using a Fast Fourier Transformation. Formalin produced biphasic pain behaviors with a transient pause between two phases. Cortical EEG recordings showed a biphasic change; a vigilant pattern (a low amplitude high frequency activity) followed by a non-vigilant pattern (a high amplitude low frequency activity), showing a good correlation with apparent arousal states of rats. Observed discrepancies between pain behaviors and EEG-measured vigilance stages included (1) a vigilant EEG pattern persisted during the transient pause of pain behavior, and (2) pain behaviors persisted even after non-vigilant EEG pattern became dominant. The results of the current study showed that there are temporal discrepancies between the pain behaviors and EEG-measured vigilance during the formalin test in rats. The temporal relationship between the 'pain' behaviors and nociception per se may not be as solid as believed.

Autoantibody inhibits binding of von Willebrand factor to glycoprotein Ib and collagen in multiple myeloma: recognition sites present on the A1 loop and A3 domains of von Willebrand factor.

A 49-year-old man with multiple myeloma (IgG-lambda Bence-Jones protein positive) presented a bleeding tendency: characterized intramuscular hemorrhage. Coagulation studies showed a von Willebrand factor (vWF) defect (Duke bleeding time > 20 min; ristocetin cofactor activity [vWF:RC] < 6%; significant reduction of large multimers of vWF. Mixing study suggested the presence of inhibitor directed against vWF:RC activity and collagen binding activity of vWF. The inhibitor was identified as an antibody of the IgG class. The inhibitor blocked the interaction of vWF with glycoprotein Ib in the presence of ristocetin, as did the pepsin-digested fragment of the inhibitor [F(ab)2'], but neither blocked botrocetin-mediated interaction of vWF with glycoprotein Ib. They also inhibited the binding of vWF to immobilized collagen type I. The inhibitor and the F(ab)2' reacted strongly with native vWF and fragment I (amino acids 911-1365) and with the 39/34 kDa fragment (amino acids 480/481-718), but not with fragment II (amino acids 1366-2050) and fragment III-T2 (heavy chains, amino acids 273-511; light chains, amino acids 674-728). We conclude that the IgG antibody inhibits both vWF:RC activity and the binding of vWF to collagen by reacting with the epitopes present on the A1 loop and A3 domains of vWF.

Extramedullary plasmacytoma of the jejunum.

A case of extramedullary plasmacytoma (EMP) of the jejunum, an uncommon neoplasia, is reported. A 56-year-old Japanese woman who experienced intermittent upper abdominal pain and weight loss had a large movable mass in the upper abdomen. The mass was hypervascular in an angiographic study and positive for gallium-67 citrate scintigraphy. Immunoelectrophoresis showed the presence of an M-component of immunoglobulin (Ig) A-lambda in the serum. It was identified as an EMP immunohistochemically positive for IgA-lambda. This M-component disappeared after resection and chemotherapy. The clinical features of this rare neoplastic disorder are discussed.

Comparison of acceleromyography and electromyography in vecuronium-induced neuromuscular blockade with xenon or sevoflurane anesthesia.

STUDY OBJECTIVES: To compare acceleromyography (AMG) and electromyography (EMG) with xenon or sevoflurane anesthesia during vecuronium-induced neuromuscular blockade. DESIGN: Prospective randomized study. SETTING: University hospital. PATIENTS: 28 ASA physical status I and II adult patients presenting for elective surgery. INTERVENTIONS: Patients received vecuronium for neuromuscular blockade and either xenon (n = 11) or sevoflurane (n = 17) anesthesia. MEASUREMENTS AND MAIN RESULTS: The first twitch depression, which was expressed as a ratio of the first twitch to that obtained before the blocking drug was administered (T1/Tc), was measured simultaneously by AMG and EMG. T1/Tc as measured by AMG consistently demonstrated greater depression than that by EMG during recovery. The limits of agreement were unacceptably wide, suggesting that T1/Tc obtained by AMG is a poor predictor of T1/Tc as measured by EMG. Such relations were not affected by the anesthetic (xenon or sevoflurane) used. CONCLUSION: AMG and EMG-cannot be used interchangeably with either xenon or sevoflurane anesthesia.

Insertion of the cuffed oropharyngeal airway (COPA) with propofol or sevoflurane in adults.

STUDY OBJECTIVES: To compare the respiratory depressant effects of propofol and sevoflurane used to facilitate the placement of the cuffed oropharyngeal airway (COPA), and to evaluate the effectiveness of the COPA in supporting positive pressure ventilation during anesthetic-induced apnea. DESIGN: Randomized, single-blinded study. SETTING: University hospital. PATIENTS: 60 ASA physical status I and II adult patients scheduled for elective surgery with general anesthesia. INTERVENTIONS: Patients were induced either with spontaneous inhalation of 5% sevoflurane or with propofol 2.0 mg/kg intravenously (i.v.) followed by a continuous infusion of 170 micrograms kg-1 min-1. If the propofol patient had a tight jaw in 90 seconds, additional propofol (0.5 mg/kg) was administered and the infusion rate was increased to 200 micrograms kg-1 min-1. The COPA was placed as soon as the jaw was sufficiently relaxed to allow its insertion into the mouth. MEASUREMENTS AND MAIN RESULTS: The median (range) time to the COPA placement were 90 seconds (30 to 150 sec) and 120 seconds (60 to 210 sec) with propofol and sevoflurane, respectively (p = 0.07, Mann-Whitney U-test). Unacceptable responses to the placement (3 or more coughs, vigorous or persistent [> 30 sec] movements) occurred in 23% and 17% of those who received propofol and sevoflurane, respectively, (p = 0.35. Chi-square test). All these responses were easily suppressed by additional doses of the assigned induction drug. After placement of the COPA, 53% (16/30) of the propofol patients had apnea lasting at least 30 seconds. Notably, the positive airway pressure at which a leak occurred in the mouth (pharyngeal leak pressure) was lower during this propofol-induced apnea than after the return of spontaneous breathing [9 (5 to 20) cmH2O vs. 15 (5 to 20) cmH2O, p < 0.01, Wilcoxon's signed-rank test]. In contrast, at no time were the sevoflurane patients apneic, and their pharyngeal leak pressure immediately following the placement was 12 (10 to 20) cmH2O. CONCLUSIONS: Propofol and sevoflurane are equally effective in facilitating the placement of the COPA. However, propofol often induces apnea, which is complicated by a less effective seal of the airway by the COPA against positive pressures. Because sevoflurane induction allows spontaneous respiration to continue and provides an adequate pharyngeal seal immediately following the placement of the COPA, it may be advantageous when apnea is not desired.

[An application of multiple logistic regression analysis to an outcome study on surgery for patients with femoral neck fracture].

Sixty five patients with femoral neck fracture were examined to find any risk factor for their postoperative complications. Here, postoperative complications included cardiac catastrophe, pulmonary embolism, central nervous system accident, and respiratory failure requiring mechanical ventilation during the period of one week after operation. Multiple logistic regression analysis was used to predict these factors. Explanatory variables were selected based on the clinical judgement. Those variable are age, sex, preoperative underlying cardiac disease, preoperative underlying respiratory complications, the use of cement for the procedure, and anesthetic technique. The analysis revealed that the sex was the only variable that was considered significant based on the P value less than 0.05. However, multi-colinearity between variables was suspected to exist based on the correlation matrix analysis which may indicate that the factor is not, in fact, significant. In short, further study will be required to find any significant variables or risk factors to predict the outcome of untoward events.

[Exercise-induced acute renal failure associated with renal vasoconstriction].

Exercise-induced acute renal failure without rhabdomyolysis is not a rare condition. We experienced 6 cases (5 men and a woman) during last the 8 years. All cases complained of severe loin pain and nausea after mild to moderate exercises (for example, a track race in an athletic meeting). The elevation of serum and urinary myoglobin was undetected. In 4 of 5 patients with abdominal CT, renal patchy vasoconstriction (wedge-shaped low-density lesion) was observed. This was diagnosed as exercise-induced acute renal failure with loin pain (serum creatinine levels: 1.7-8.6 mg/dl). The renal function in 5 of the 6 cases normalized in about three weeks by fluid replacement therapy and hemodialysis support, which one patient received for 3 days. One patient required a long time for improvement of renal function and renal insufficiency persisted (serum creatinine 1.8 mg/dl). In 2 patients, the concentration of serum uric acid became very low after the recovery of renal function. These two patients were diagnosed as an isolated hyperuricosuric hypouricemia. More than half of the 6 patients had previously experienced the same episodes (loin pain and nausea) after exercise. Exercise-induced acute renal failure, probably due to renal patchy vasoconstriction, seems to be not a rare disease. The etiology of renal patchy vasoconstriction after exercises remains to be elucidated. The occurrence of acute renal failure must be taken into consideration when the youngster, especially with renal hypouricemia, complains of severe loin pain and nausea after exercise such as a track race.

[Graves' disease complicated with systemic lupus erythematosus (SLE): a case report].

A 25 year old man had been subjected to subtotal thyroidectomy under the diagnosis of Graves' disease. About a year later the patient developed systemic lupus erythematosus (SLE). Reports on cases of Graves' disease complicated with SLE have barely been observed so far. Consequently, the authors reckoned, with reference to the other literatures on the subject, our case worth reporting.

[A case of blue rubber-bleb nevus syndrome with CAPD].

The first case of blue-rubber-bleb nevus syndrome treated with CAPD in Japan was presented. As operation for A-V fistula construction could not be performed due to the skin lesions, she was obliged to have CAPD treatment. She has been visiting our hospital for regular check-ups.

A retrospective survey of adverse maternal and neonatal outcomes for parturients with congenital heart disease.

BACKGROUND: Parturients with congenital heart disease are at increased risk of maternal cardiac and neonatal complications. There is a paucity of literature regarding the relationship of complications with the type of anesthesia or mode of delivery. METHODS: We retrospectively reviewed all parturients with congenital heart disease undergoing delivery over a 7-year period at Tokyo Women's Medical University, Maternal and Perinatal Center to identify maternal cardiac and neonatal complications occurring during the peripartum period. RESULTS: Of 151 pregnancies in 128 women with congenital heart disease, there were 84 vaginal and 67 cesarean deliveries. Cesarean deliveries were performed with either neuraxial (n=51) or general (n=16) anesthesia. There were no maternal deaths and two neonatal deaths (one vaginal; one cesarean delivery). The incidence of maternal cardiac events was 1 in 84 (1%) for vaginal deliveries and 10 in 67 (15%) for cesarean deliveries. Neonatal complications occurred in 11 of 84 (13%) pregnancies with vaginal delivery and 25 of 67 (37%) pregnancies with cesarean delivery. Twenty-three elective cesarean deliveries occurred for maternal cardiac problems and were associated with a significant incidence of maternal cardiac (35%) and neonatal (65%) complications. The incidence of maternal cardiac events during delivery, when stratified by severity of cardiac disease, was similar to a previously derived cardiac risk index for pregnant women with cardiac disease. CONCLUSION: Despite a low overall incidence of maternal and neonatal mortality, pregnancy in women with congenital heart disease was associated with significant maternal cardiac and neonatal complications. Elective cesarean delivery with neuraxial anesthesia was a common approach for high-risk parturients with congenital heart disease; however, the benefit of this mode of delivery and anesthetic technique could not be ascertained.

The effect of propofol on normal and increased pulmonary vascular resistance in isolated perfused rabbit lung.

The effects of propofol and its intralipid vehicle on increased and normal pulmonary vascular resistances (PVR) were studied in an in situ perfused rabbit lung model which controlled all major determinants of PVR. Propofol at both 5 and 10 micrograms/mL significantly reduced PVR increases by the thromboxane mimetic, U46619. In contrast, similar volumes of intralipid further increased PVR. Neither propofol nor intralipid had any effect on normal PVR. We conclude that propofol at 5 and 10 micrograms/mL is able to reduce increased PVR but has no effect on normal PVR.

The type III phosphodiesterase inhibitor milrinone and type V PDE inhibitor dipyridamole individually and synergistically reduce elevated pulmonary vascular resistance.

The effects of the phosphodiesterase (PDE) inhibitors milrinone and dipyridamole were studied in an in situ perfused rabbit lung model in which the pulmonary vascular resistance (PVR) was elevated by infusion of the thromboxane-A2 mimetic U46619. Dose-response curves for reduction of elevated PVR were generated for each of these drugs. The EC50 for milrinone was approximately 2 microM. The EC50 for dipyridamole was approximately 0.2 microM. In separate experiments, 0.1 microM milrinone was found to reduce elevated PVR by 4.6 +/- 2.4%, 0.06 microM dipyridamole reduced elevated PVR by 8.2 +/- 2.8%, whereas the combination of 0.1 microM milrinone and 0.06 microM dipyridamole reduced elevated PVR by 41.9 +/- 7.3%. In more limited experiments, it was determined that the PDE type V inhibitor zaprinast also caused a synergistic reduction of PVR when used with milrinone. We concluded that both the type III PDE inhibitor milrinone and the type V PDE inhibitors dipyridamole or zaprinast are effectively able to reduce elevated PVR and that the combination of PDE type III and type V inhibitors is synergistic in the ability to reduce elevated PVR. We speculate that type V PDE may play a more important role than type III PDE in the regulation of pulmonary vascular tone. It is proposed that the combination of milrinone and dipyridamole has the potential to be useful in the clinical treatment of elevated PVR.

Emergence times from xenon anaesthesia are independent of the duration of anaesthesia.

Xenon (MAC = 71%) has an extremely low blood:gas partition coefficient (0.14). Therefore, we predicted that the rate of emergence from xenon anaesthesia would not be affected greatly by duration of anaesthesia. We studied 54 ASA I-II patients undergoing lower abdominal surgery who received equal MAC anaesthesia with 60% xenon, 60% nitrous oxide with 0.5% isoflurane or 60% nitrous oxide with 0.7% sevoflurane (n = 18 per group), each supplemented with extradural mepivacaine anaesthesia. Duration of anaesthesia was 58-380 min. At the end of operation, all inhalation anaesthetics were discontinued and patients were allowed to wake up while breathing oxygen spontaneously. A blinded investigator recorded the time until patients opened their eyes on command (T1), were judged ready for tracheal extubation (T2), could correctly state their name, date of birth and name of the hospital (T3), and could count backwards from 10 to 1 in less than 15 s (T4). Emergence times after xenon and nitrous oxide-sevoflurane anaesthesia did not correlate with duration of anaesthesia, whereas those from nitrous oxide-isoflurane had positive correlations. Mean emergence times from xenon anaesthesia were: T1, 3.3 (SD 1.0) min; T2, 3.6 (1.0) min; T3, 5.0 (1.1) min; and T4, 6.2 (1.7) min. These values were approximately 50% of those after nitrous oxide-sevoflurane anaesthesia (T1, 5.6 (1.4) min; T4, 10.5 (2.0) min). We conclude that xenon provided fast emergence from anaesthesia, regardless of the duration of anaesthesia.

The placement of the cuffed oropharyngeal airway with sevoflurane in adults: a comparison with the laryngeal mask airway.

UNLABELLED: We sought to determine the anesthetic duration of sevoflurane required to achieve good conditions for placement of a cuffed oropharyngeal airway (COPA) or a laryngeal mask airway (LMA). Forty adult ASA physical status I or II patients presenting for elective surgery received single-breath vital capacity inhaled induction with 5% sevoflurane via face mask; thereafter, ventilation was manually assisted. The patients were randomized to receive either a COPA or LMA placement. The time of anesthetic exposure was varied for consecutive patients using the staircase method. The mean (95% confidence interval) anesthetic time required for acceptable COPA placement (100 [55-145] s) was significantly shorter than that for LMA (160 [101-219] s). The 50% and 95% effective doses (from logistic analyses) for acceptable conditions associated with COPA or LMA placement were 90 s and 145 s or 164 s and 261 s, respectively. These findings suggest that COPA insertion is less stimulating than the LMA. IMPLICATIONS: The cuffed oropharyngeal airway is a new airway device that is similar to a laryngeal mask airway in many ways. However, it requires shorter anesthetic duration for successful placement, which suggests that it can be placed with less stimulation. It may be an alternative to a laryngeal mask airway.

Relationship between end-tidal and arterial carbon dioxide partial pressure using a cuffed oropharyngeal airway and a tracheal tube.

We have compared the differences between end-tidal PE'CO2 and arterial PaCO2 carbon dioxide partial pressures during general anaesthesia using either a cuffed oropharyngeal airway (COPA) or a tracheal tube (TT) in spontaneously breathing adult patients. After induction of anaesthesia, a COPA was inserted in 20 patients who were allowed to breathe spontaneously. When steady state was reached, PE'CO2 and PaCO2 were recorded. The COPA was removed, the trachea intubated with a TT and spontaneous ventilation allowed to resume. After a stable PE'CO2 was reestablished, PaCO2 was measured again and PE'CO2 recorded. Mean difference between PaCO2 and PE'CO2 with the COPA was 0.72 (SD 0.45) kPa and with the TT 0.64 (0.40) kPa (ns; paired t test). Our results suggest that Pe'CO2 is a clinically acceptable indicator of PaCO2 in adults breathing spontaneously via a COPA.

The blood-gas partition coefficient of xenon may be lower than generally accepted.

The blood-gas partition coefficients of xenon, reported more than 25 yr ago in the literature, vary considerably from 0.13 to 0.20. Consequently, we have determined this variable by directly injecting xenon-saturated blood into a gas chromatograph-mass spectrometer. This technique yielded a blood-gas partition coefficient for xenon of 0.115 (95% confidence interval 0.107-0.123). The solubility in water measured identically was 0.096, consistent with the reported value of 0.085. These data and a detailed review of the literature strongly suggest that the blood-gas partition coefficient of xenon may be lower than the generally accepted value of 0.14.

The effects of heparin coating of oxygenator fibers on platelet adhesion and protein adsorption.

UNLABELLED: Platelet adhesion on the cardiopulmonary bypass oxygenator membrane is associated with impaired hemostasis. We investigated the effects of heparin coating of the oxygenator membrane on protein adsorption and platelet adhesion on the surface. Noncoated and heparin-coated polypropylene membranes were incubated in whole blood with small- (1 U/mL) or large-dose (5 U/mL) heparin as an anticoagulant for 3 h at 37 degrees C. The amount of platelets adhering on each fiber was assessed by using enzyme immunoassays using monoclonal antibodies directed against CD42b (GP Ib) and CD61 (GP IIb/IIIa). Platelet activation was assessed by measuring plasma guanosine monophosphate 140 levels. The amount and composition of the adsorbed proteins on the surface were analyzed by using a bicinchoninic acid protein assay and by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting technique. The heparin coating of the fibers significantly reduced platelet adhesion on the surface. However, platelet activation was reduced by heparin coating only with small-dose heparinization. The adsorption of platelet adhesive proteins such as fibrinogen and von Willebrand factor was not altered, whereas that of fibronectin was increased by heparin coating. We conclude that heparin coating of the oxygenator fibers can decrease platelet adhesion without affecting adsorption of major adhesive proteins. Surface heparin coating is associated with an increased fibronectin adsorption on the fibers. IMPLICATIONS: Heparin coating can reduce platelet adhesion and activation in the presence of small-dose heparinization, potentially reducing the inflammatory response and activation of thrombosis and fibrinolysis.