Celite-activated viscometer Sonoclot can measure the suppressive effect of tranexamic acid on hyperfibrinolysis in cardiac surgery

Purpose. To investigate the usefulness of the celite-activated viscometer Sonoclot for monitoring fibrinolytic status in cardiac surgery, we demonstrated the effectiveness of high doses of tranexamic acid, an antifibrinolytic agent, in reducing postoperative bleeding. Methods. Thirty-two American Society of Anesthesiologists (ASA) physical status III patients who required cardiac surgery with cardiopulmonary bypass (CPB) were studied. Anesthesia was induced by a high dose of fentanyl and midazolam with oxygen and was maintained by the intermittent administration of these agents. Patients were divided into two groups: the control group (n = 15) and patients receiving tranexamic acid (TA; n = 17). The TA group received a high dose (50 mg/kg) of TA twice, once before and once after CPB. The percentage diminishing rate of the Sonoclot tracing 15 min after maximum clot signal (DR₁₅) and the amount of postoperative bleeding were measured. Results. After CPB, DR₁₅ in the control group (mean 28.3%) increased significantly by 45%, and the DR₁₅ in the TA group (16.1%) was significantly lower than that in the control group. The amount of postoperative bleeding in the TA group (546 ml) was significantly less, by 34%, than that in the control group (829 ml). Conclusion. Prophylactic administration of high-dose TA in cardiac surgery reduces postoperative bleeding, and this effect is consistent with changes in the diminishing rate using Sonoclot. The celite-activated viscometer Sonoclot is recommended for use in cardiac surgery for rapid assessment of fibrinolytic status. Received: May 23, 2000 / Accepted: September 26, 2000     

Transplantation of human neural progenitor cells to the vitreous cavity of the Royal College of Surgeons rat

Human neural progenitor cells, originally isolated from prenatal donor tissue at 17 weeks of development, were cultured as neurospheres and transplanted to the vitreous cavity of dystrophic Royal College of Surgeons rats with, or without, cyclosporin A immunosuppression. Donor cells were either unlabeled or prelabeled, the latter utilizing incubation with BrdU or adenoviral modification to express green fluorescent protein. Recipients of various ages were examined at 1, 2, and 4 weeks postgrafting. Transplanted human neural progenitor cells survived in the host vitreous for at least 4 weeks and maintained expression of green fluorescent protein for at least 2 weeks. After 2 weeks in vivo, grafted cells differentiated morphologically, coincident with expression of the neuronal marker MAP, indicating mature neuronal differentiation. The extensive intraretinal migration previously shown using rat progenitor cells in the Royal College of Surgeons rat model was not seen in this experiment, suggesting that high levels of neuronal migration may depend at least in part upon species-specific molecular cues. Human neural progenitor cells represent a renewable source of multipotent human cells capable of in vivo neuronal development and a potential means of delivering therapeutic factors intraocularly. Human neural progenitor cells therefore provide a useful tool for studies of neural development and differentiation in the dystrophic eye.     

Effect of low-dose milrinone on gastric intramucosal pH and systemic inflammation after hypothermic cardiopulmonary bypass

OBJECTIVE: To investigate the usefulness of low-dose milrinone on gastric intramucosal pH (pHi) and systemic inflammation in patients undergoing hypothermic cardiopulmonary bypass (CPB). DESIGN: Prospective randomized study. SETTING: University hospital. PARTICIPANTS: Twenty patients scheduled for cardiac surgery. INTERVENTIONS: Ten patients were administered a low dose of milrinone, 0.25 microg/kg/min, from the initiation of CPB to 1 hour after admission to the intensive care unit. The other patients were administered saline. Supplemental inotropes and intravenous fluid were given to obtain adequate mean arterial blood pressure and pulmonary artery occlusion pressure. MEASUREMENTS AND RESULTS: Gastric pHi and carbon dioxide pressure (PCO2) were assessed by capnometric air tonometry. The difference between PCO2 and arterial carbon dioxide pressure (PaCO2), PCO2-gap, was also examined. Systemic inflammatory responses were evaluated by serum interleukin-6 and leukocyte counts. Hemodynamics, oxygen delivery index, and oxygen uptake index were monitored with catheters in the radial and pulmonary arteries (thermodilution). The hepatic venous blood flow and left ventricular flow were measured using transesophageal echocardiography. Milrinone prevented gastric intramucosal acidosis, detected as a decrease in pHi or an increase in PCO2-gap, without affecting hepatic venous blood flow. Increases in interleukin-6, leukocyte count, and oxygen uptake index, all of which developed after CPB, were significantly less in the milrinone group than in the control group. CONCLUSION: These results suggest that in patients undergoing hypothermic CPB, supplemental low-dose milrinone prevents gastric intramucosal acidosis and increases in some markers of systemic inflammation.     

Production of compound A under low-flow anesthesia is affected by type of anesthetic machine

Purpose

The purpose was to compare the concentrations of compound A in inspired gas breathed by patients produced by different types of anesthetic machines under prolonged sevoflurane low-flow anesthesia.

Methods

The anesthetic machines tested were Excel? 210 SE (Datex-Ohmeda, Louisville, CO), Cicero? (Dräger, Lübeck, Germany), and AS/3? ADU (Datex-Ohmeda, Louisville, CO). Anesthesia expected to last more than four hours was maintained with 2.0% sevoflurane and nitrous oxide (0.5 L·min^?1) / oxygen (0.5 L·min^?1). The concentrations of compound A, obtained from the inspiratory limb of the circle system, were measured using a gas Chromatograph.

Results

When Excel? and Cicero? were used, concentrations of compound A increased steadily from the baseline values to 28 and 29 (mean) ppm, respectively, at two hours after exposure to sevoflurane and became constant. There was no significant difference between the concentrations of compound A produced by these anesthetic machines. In contrast, the new anesthetic machine AS/3? was associated with lower concentrations of compound A (6 ppm at one hour, P < 0.05 compared with Excel? and Cicero?), and the concentration did not change significantly thereafter.

Conclusion

In spite of the use of a conventional carbon dioxide (CO₂) absorbent with strong bases, the anesthetic machine AS/3? with a small volume of canister/soda lime (900 ml/700 ml) produced lower concentrations of compound A than those produced by the other machines.     

Values of the bispectral index do not parallel the hemodynamic response to the rapid increase in isoflurane concentration

PURPOSE: To investigate the changes in hemodynamic variables and bispectral index (BIS) in response to a rapid increase in isoflurane or sevoflurane concentration. METHOD: Thirty adult patients were anesthetized with either isoflurane (isoflurane group) or sevoflurane (sevoflurane group). Two minutes after induction of anesthesia with thiamylal, the inspired concentrations of isoflurane and sevoflurane were rapidly increased from 0.5 minimum alveolar anaesthetic concentration (MAC) to 3 MAC and maintained for five minutes. Heart rate (HR), mean arterial pressure (MAP), and BIS were measured every minute. RESULTS: An increase in the anesthetic concentration caused increases in HR and MAP in the isoflurane group and a decrease in MAP in the sevoflurane group. Consequently, HR and MAP in the isoflurane group were significantly higher than those in the sevoflurane group. After inhalation of high concentrations, BIS significantly and progressively decreased in both groups. CONCLUSION: BIS values decrease after a step increase in volatile agent concentration, whether or not a hyperdynamic action occurs.     

Neuronal migration disturbance and consequent cytoarchitecture in the cerebral cortex following transplacental administration of methylmercury

To understand the effects of methylmercury (MeHg) on neuronal migration in the developing cerebral cortex, we performed double administrations of MeHg and 5-bromo-2-deoxyuridine (BrdU) to pregnant rats on different embryonic days (E11, E13, E16 or E21). Histopathological examination of a proportion of the offspring on postnatal day 28 revealed no apparent cytoarchitectural abnormalities in the primary motor and primary somatosensory cortices of the cerebrum. Morphometric analysis revealed no significant differences in total neuron population in either of these areas, and no differences in subpopulations of cells in any of the cortical layers, between any of the MeHg-exposed groups and the control animals. However, BrdU immunohistochemistry revealed an abnormally widespread distribution of the labeled cells throughout cortical layers II-VI of offspring exposed to MeHg on E16 and E21, indicating disruption of the inside-out pattern of neuronal migration. We examined one aspect of cell-fate determination by applying immunohistochemistry with antibodies against calbindin, parvalbumin, calretinin, and gamma-aminobutyric acid, but found no differences in the topographic distributions of the antibody-labeled cells in the cortex between the controls and the MeHg-exposed offspring. These results suggest that it is the extrinsic circumstances - rather than the timing of neuron generation - that regulates the expression of these proteins.     

Usefulness of self-expandable metallic stent with an antireflux mechanism as a palliation for malignant strictures at the gastroesophageal junction

BACKGROUND: Patients with unresectable malignant gastroesophageal strictures often are troubled with reflux esophagitis after stent placement. METHODS: A self-expandable metallic stent (SEMS) without an antireflux mechanism was placed in seven patients with unresectable malignant gastroesophageal strictures (group A), and SEMS with an antireflux mechanism was placed in five patients (group B). After we obtained monitoring systems, two patients in group A and all the patients in group B underwent measurement of bilirubin and pH in the esophagus using a 24-h bilirubin and pH monitor. RESULTS: The mean percentage of total time less than 0.14 for use of the bilirubin absorbance unit was 12.4% in group B and 64.0% in group A. The mean percentage of total time for a pH less than 4 was 2.9% in group B and 37.8% in group A. CONCLUSION: The placement of SEMS with the antireflux mechanism can be effective not only for palliation of gastroesophageal stricture, but also for prevention of reflux.     

Treatment of Status Asthmaticus—Hormone Changes before and after Aminophylline i.v. Drip Therapy

The treatment of status asthmaticus is one of the most important factors in controlling the patient with asthma attacks. We have studied hormone changes in status asthmaticus and considered what is the best treatment in the asthma attack condition in children. Antidiuretic hormone (ADH), renin activity, and aldosterone activity are elevated in severe asthma attack conditions, and these high levels are correlated with high levels in Wood's clinical score. It is theoretical that patients with dehydration and respiratory failure show such elevation in hormones, and it is well known that under such conditions β₂-stimulant enhances renin production. From our study, it is concluded that β₂2 -stimulant subcutaneous injection must be considered in status asthmaticus. In children, amminophylline i.v. drip therapy may be one of the best treatments in status asthmaticus.     

Mandibular nerve block treatment for trismus associated with hypoxic-ischemic encephalopathy

BACKGROUND AND OBJECTIVES: We describe the use of mandibular nerve block for the management of bilateral trismus associated with hypoxic-ischemic encephalopathy. CASE REPORT: The patient was a 65-year-old man with bilateral trismus due to hypoxic-ischemic encephalopathy. Despite his impaired consciousness, we performed fluoroscopically guided bilateral mandibular nerve block. The bilateral symptoms were sufficiently improved, without obvious side effects, by injecting a local anesthetic near the right mandibular nerve and a neurolytic near the left mandibular nerve. CONCLUSIONS: Mandibular nerve block may be an effective treatment for patients with bilateral trismus due to ischemic-encephalopathy, even when consciousness is impaired.