Comparison of hemodynamic and anesthetic effects of hyperbaric bupivacaine and tetracaine in spinal anesthesia

Purpose.To compare the anesthetic and hemodynamic effects and the predictive factor of anesthesia level of commonly used preparations of hyperbaric bupivacaine and tetracaine in spinal anesthesia. Methods.Two hundred patients aged 40 to 75 years with ASA physical status I or II were anesthetized spinally via the L4–5 interspace using 0.5% hyperbaric bupivacaine in 7.27% glucose (Bupivacaine group, n = 100) or 0.5% hyperbaric tetracaine dissolved in a 10% glucose solution (Tetracaine group, n = 100) in a lateral position. The volume of anesthetic used was decided by the resident according to the surgical procedure. Patients were returned to the supine position immediately after drug injection. Blood pressure, heart rate, and anesthesia level tested by cold sensation were measured for 30min. Results.Blood pressure and heart rate decreased significantly but without any differences between the groups. The volume of drug used was significantly larger in the Bupivacaine group (2.6 ± 0.5ml) than in the Tetracaine group (2.1 ± 0.4ml) to obtain the same maximum anesthesia level. The time to reach the maximum anesthesia level was significantly longer in the Bupivacaine group (18 ± 7min) than in the Tetracaine group (15 ± 6min). The volume of the drug was the only predictive factor of the maximum anesthesia level in both groups: Level (as expressed by the number of anesthetized segments from S5 to cephalad) = 1.55 × (volume in ml) + 13.06 in the Bupivacaine group, and 2.59 × (volume) + 11.46 in the Tetracaine group. Conclusion.In spinal anesthesia, hyperbaric tetracaine in 10% glucose induced a faster and higher spread of anesthesia than hyperbaric bupivacaine in 7.27% glucose without any differences in hemodynamics.     

Halothane modulates NMDA and non-NMDA excitatory synaptic transmission in rat cortical neurons

Purpose Although general anesthetics may decrease neuronal excitation, their detailed effects on spontaneous excitatory postsynaptic currents (EPSCs) remain controversial. We investigated and compared the effects of halothane on N-methyl-d-asparate (NMDA) and non-NMDA receptor-mediated postsynaptic currents.Methods Spontaneous synaptic currents were recorded by the patch clamp technique in cultured rat cortical neurons. They were isolated by specific pharmacological blocking agents and their electrophysiologic properties were examined.Results The frequency of NMDA EPSCs was preferentially decreased as compared with that of non-NMDA EPSCs at halothane 1.2mM. The total net charge of EPSCs mediated by NMDA and non-NMDA receptors was depressed to 56% ± 6% (mean ± SD) and 71% ± 7% of control by halothane 0.6mM, and to 11% ± 9% and 59% ± 11% of control by halothane 1.2mM, respectively.Conclusion These results show that halothane causes decrease of excitatory synaptic activity, with NMDA EPSCs being more sensitive than non-NMDA EPSCs.     

Portal Hypertensive Gastropathy After Surgery for Biliary Atresia

Purpose To clarify the correlation between portal hypertensive gastropathy (PHG) and clinical features after surgery for biliary atresia (BA).Methods Routine upper gastrointestinal endoscopies were done over 3 years in 27 children who underwent surgery for BA. We reviewed the recorded endoscopic findings, and retrospectively diagnosed PHG according to McCormacks criteria. The differences in clinical features, such as endoscopically treated gastroesophageal varices and the results of routine laboratory tests, were compared between the children with PHG (PHG group) and those without PHG (non-PHG group).Results Nine (33%) of the 27 children had PHG. Although there was no significant difference in age between the PHG and non-PHG groups, the frequency of past endoscopic variceal treatments was significantly higher in the PHG group (3.0 ± 3.0 vs 0.6 ± 1.5 times, P = 0.01). The PHG group also had lower white blood cell and platelet counts, at 3008 ± 2411 vs 5527 ± 2938/mm³ (P < 0.05) and 6.0 ± 3.4 vs 13.9 ± 4.7 × 10⁴/mm³ (P = 0.0001), respectively; higher serum aspartate aminotransferase, total bile acid, and total bilirubin levels at 80 ± 31 vs 46 ± 29U/l (P < 0.05), 161 ± 93 vs 64 ± 88U/l (P < 0.05), and 4.8 ± 5.6 vs 1.0 ± 0.8mg/dl (P < 0.01), respectively; and lower prothrombin time, albumin, and cholinesterase levels, at 66 ± 16 vs 79% ± 14% (P < 0.05), 3.6 ± 0.8 vs 4.1 ± 0.5g/dl (P < 0.05), and 2158 ± 925 vs 3376 ± 700U/l (P < 0.001), respectively.Conclusion Portal hypertensive gastropathy was found in 33% of children after surgery for BA. The factors contributing to the development of PHG were frequent endoscopic treatments of gastroesophageal varices, liver dysfunction, and hypersplenism.     

Comparison of anesthetic effects of epidural and intravenous administration of buprenorphine during operation

Thirty six patients were received epidural anesthesia with or without buprenorphine (BPN) during upper abdominal surgery. They were divided into three groups of 12 patients as follows; G-I received 20ml of 1% lidocaine epidurally, G-II received 20ml of 1% lidocaine epidurally and 0.6mg BPN intravenously, G-III received 20ml of 1% lidocaine with 0.6mg BPN epidurally. Additional 5ml of 1% lidocaine was given to any patient if systolic blood pressure or heart rate increased 10% compared to control value. Trachea was intubated following anesthetic induction with thiopental. The lungs were ventilated with a mixture of N₂O/O₂ (33%) and pancuronium was used for muscle relaxation. The total required doses of lidocaine in G-II and G-III were decreased 60% compared to control group (G-I) (P 0.05). The mean period of time until the first administration of pentazocine for postoperative pain was 13 ± 10hr (mean ± SD) in G-II and 19 ± 24hr in G-III compared to 5 ± 4hr in G-I (P 0.001). The dose of the administration of pentazocine that was required for pain relief during the first 48 postoperative hr in G-III was 54 ± 10mg (mean ± SD) compared to 150 ± 21mg in G-I (P 0.02) and 106 ± 28mg in G-II (P 0.05). Recovery from anesthesia in G-III was more rapid than that in G-I (P 0.05). The Pa_{CO 2} values in G-II and G-III increased 15% compared to control group at about 4hr and 8hr after administration of BPN, but any clinical treatment was not needed for them. Nonrespiratory side effects, e.g., nausea, vomiting, fatigue and headache, were comparably common in all groups. Mild hematuria associated with acute hypotension occurred in two patients in G-II (17%) immediately after the intravenous injection of 0.6mg of BPN. The results showed that 0.6mg of BPN given epidurally demonstrated better anesthetic and more potent postoperative analgesic effects and lesser side effects than 0.6mg of BPN given intravenously in patients undergoing upper abdominal surgery.(Yonemura E, Fukushima K.: Comparison of anesthetic effects of epidural and intravenous administration of buprenorphine during operation. J Anesth 4: 242–248, 1990)     

The intrathecal spread of hyperbaric dibucaine in adolescents

We investigated the spread of spinal anesthesia with hyperbaric dibucaine in 20 adolescents aged 9–18yr and 20 adults aged 23–53yr. No significant difference was found between the two groups with regard to height, whereas a statistical significant was found between the two groups with regard to weight. Spinal anesthesia was conducted with Neo-Percamin S^® injected at the L3–L4 interspace through a 25-gauge spinal needle. Injected volumes of the anesthetic solution were calculated from the patients height at 0.01ml·cm^–1. In adolescents, 1.6 ± 0.1ml (mean ± SD) of the anesthetic solution produced 19.4 ± 1.5 spinal segments blocked. In adults, 1.6 ± 0.1ml of the solution produced 13.4 ± 1.6 spinal segments blocked. A high spinal anesthesia above T5 was achieved in 17 (85%) patients in adolescents, whereas such a high level of spinal anesthesia was not experienced in adults. These results suggest that the hyperbaric dibucaine solution for spinal anesthesia in adolescents may have a tendency to produce an unexpectedly extensive spread of anesthesia.(Hirabayashi Y, Shimizu R: The intrathecal spread of hyperbaric dibucaine in adolescents. J Anesth 7: 167–172, 1993)     

Effects of calcium and temperature on tension in isolated canine coronary artery

The effects of calcium and temperature on the tension of isolated canine coronary arterial strips were studied.In 20mEq·l ^–1 K solution, the tension was significantly increased from 0mg with 0mEq·l ^–1 Ca to 33 ± 18mg with 0.2mEq·l ^–1 Ca at 37°C, from –40 ± 18mg with 0mEq·l ^–1 Ca to –17 ± 11mg with 0.2mEq·l ^–1 Ca at 30°C, from –77 ± 19mg with 0mEq·l ^–1 Ca to –52 ± 17mEq·l ^–1 with 1mEq·l ^–1 Ca at 25°C, from –88 ± 13mg with 0mEq·l ^–1 Ca to –41 ± 18mg with 2mEq·l ^–1 Ca at 20°C, from –125 ± 16mg with 0mEq·l ^–1 Ca to –116 ± 13mg with 2mEq·l ^–1 Ca at 15°C. Ca higher than 0.2mEq·l ^–1 produced a dose-dependent increase in tension between 37°C and 15°C. In spite of the presence of 4mEq·l ^–1 Ca, the development of tension was strongly supressed by lowering the temperature below 20°C, and completely inhibited at 10°C. The rate of a decrease in tension caused by cooling was about 5.5mg·°C^–1.This study demonstrated that Ca²⁺ produced a dose-dependent increase in tension in high-K solution, which was suppressed as the temperature was lowered.(Yoshida K, Fujii Y, Ina H, et al.: Effects of calcium and temperature on tension in isolated canine coronary artery. J Anesth 5: 172–176, 1991)     

Plasma concentration for optimal sedation and total body clearance of propofol in patients after esophagectomy

The present study investigated plasma propofol concentration for optimal sedation and total body clearance in patients who required sedation for mechanical ventilation after esophagectomy. Seven patients after esophagectomy were enrolled in this study. Plasma propofol concentrations were measured with high performance liquid chromatography. Total body clearance was calculated from the steady-state concentration. The infusion rate of propofol for achieving the sedation score of level 3 (drowsy, responds to verbal stimulation) was 1.74 ± 0.82mgkg^–1h^–1 (mean ± SD, n = 7) when the plasma propofol concentration and the total body clearance were 0.85 ± 0.24µgml^–1 and 1.83 ± 0.54lmin^–1 (mean ± SD, n =7), respectively.     

Inhaled Nitric Oxide Therapy After Fontan-Type Operations

Purpose Inhaled nitric oxide (NO) therapy is a newly developed strategy designed to reduce pulmonary vascular resistance after the Fontan-type operation. We reviewed our experience to evaluate its efficacy and true indications.Methods We retrospectively examined 47 children who received inhaled NO therapy after the Fontan-type operation between August 1996 and December 2002. The maximal dose of NO ranged from 5 to 30ppm (median 10ppm), and the duration of inhaled NO therapy ranged from 5h to 52 days (median 2 days).Results Inhaled NO significantly decreased the central venous pressure (CVP), from 16.2 ± 2.2 to 14.6 ± 2.2mmHg (P < 0.0001), and the transpulmonary pressure gradient between the CVP and left atrial pressure, from 9.9 ± 2.9 to 8.4 ± 2.7mmHg (P < 0.0001). It also increased the systolic systemic arterial pressure from 71.9 ± 15.2 to 76.8 ± 14.5mmHg (P < 0.05). In 26 patients with additional fenestration, inhaled NO led to a significant improvement in SaO₂ from 90.1% ± 9.6% to 93.3% ± 7.9% (P < 0.01). However, patients with a CVP <15mmHg or a transpulmonary pressure gradient <8mmHg, or both, after the Fontan-type operation, showed no significant changes in hemodynamics during inhaled NO therapy.Conclusions We propose that a CVP 15mmHg or a transpulmonary pressure gradient 8mmHg, or both, after Fontan-type operations are appropriate indications for inhaled NO therapy.     

Percutaneous and Open Renal Revascularizations Have Equivalent Long-Term Functional Outcomes

Atherosclerotic renal artery stenosis is a significant cause of poorly controlled hypertension and progressive renal dysfunction leading to ischemic nephropathy and other end-organ damage. The optimal treatment of renovascular disease contributing to hypertension and renal dysfunction is not known. This study compares the anatomic and functional outcomes of both open and endovascular therapy for chronic, symptomatic atherosclerotic renal artery disease. We performed a retrospective analysis of records from patients who underwent renal arterial interventions, endovascular or open bypass, between January 1984 and January 2004. Principal indications for intervention were hypertension (51%), chronic renal insufficiency (13%), and hypertension and elevated creatinine (36%). A total of 247 patients (109 males; mean age 69±10, range 44–89 years) underwent 314 interventions (109 open procedures; 205 angioplasties, 71% with stent placement). There was a significant difference in 30-day mortality (4% vs. <1%; p < 0.005) between the open and endoluminal groups, but not at 1, 3, or 5 years. Patients in the open group had a higher primary patency rate at 5 years (83±5% vs. 76±6%; p=0.03), but patients in the endoluminal group had a higher assisted primary patency rate at 5 years (92±5% vs. 84±5; p=0.03). There was no significant difference between both treatment groups in cumulative freedom from presenting symptom or in freedom from dialysis and renal-related death. Patients who presented with hypertension were more likely to have shown improvement in their blood pressure with endoluminal intervention at 1, 3, and 5 (59±6% endoluminal vs. 83±5% open; p=0.01) years. From these results we conclude that open repair and endoluminal repair of atherosclerotic renal artery stenosis have similar immediate and long-term functional and anatomic outcomes. Patients who present with hypertension may have greater benefit with an endoluminal repair.Presented at the Twenty-ninth Annual Meeting of the Peripheral Vascular Surgery Society, Anaheim, CA, June 4-5, 2004.     

Changes of local brain tissue oxygen pressure after vasopressin during spontaneous circulation

Summary. Background. Brain tissue oxygen pressure (PbtO₂) correlates to cerebral blood flow (CBF) during spontaneous circulation, with one important regulator being nitric oxide (NO). Although it is established that arginine vasopressin (AVP) improves CBF and global cerebral oxygenation during cardiopulmonary resuscitation, it is unknown whether similar beneficial effects are present during spontaneous circulation. The purpose of this study was to investigate the effects of AVP with and without pre-treatment with the NO synthase inhibitor N-omega-nitro-L-arginine methyl ester (L-NAME) on local brain tissue oxygenation in a beating heart model.Methods. Following approval of the Animal Investigational Committee, nine healthy piglets underwent general anaesthesia, and were instrumented with a probe in the cerebral cortex to measure PbtO₂. Each animal was assigned to receive AVP (0.4U·kg^–1), and after a wash-out period, L-NAME (25mg·kg^–1 over 20min) followed by AVP (0.4U·kg^–1). After each AVP administration, nitroglycerine (25µg·kg^–1 over 1min) as a NO donor was infused to test the vascular reactivity independently from NOS inhibition.Findings. Three minutes after administration of AVP, PbtO₂ increased significantly (P<.05; mean±SEM, 31±11 versus 43±14mmHg, +39%), compared with baseline. After pre-treatment with L-NAME, the changes of PbtO₂ after AVP were not significant (32±11 versus 28±10, –13%) when compared with the baseline.Conclusion. In this beating heart porcine model, local brain tissue oxygenation was improved after AVP alone, but not after inhibition of NO synthesis with L-NAME.     

Delayed discharge and acceptability of ambulatory surgery in adult outpatients receiving general anesthesia

Purpose Delay in discharge after ambulatory surgery impairs its cost-effectiveness. However, it is not self-evident that prolonged postoperative stay is associated with low quality of care and patient acceptability of ambulatory surgery. The aims of this study were to document factors affecting delay in discharge, recovery profiles, and patient acceptability in adult outpatients.Methods Perioperative data were collected prospectively on consecutive 726 adult same-day surgical patients receiving general anesthesia. Factors that affected home-readiness, discharge, and unanticipated admission were noted. Patients were followed up 24h after discharge using a standardized questionnaire to identify postdischarge symptoms, patients self-rated resumption of normal activity (RNA) level, and preference of outpatient procedure.Results Eighty-two percent of patients were discharged home <270min after operation, 16% were delayed (270min), and 2% required unanticipated admission. Delayed patients reported postdischarge pain more frequently (53%) and a lower 24-h postoperative RNA level (7.2 ± 1.8) and preference ratio (76%) than no-delay patients (34%, 8.0 ± 1.9, 87%, respectively; P < 0.001). Delay in home-readiness (165min) was mainly due to an adverse symptom, and delay in discharge after reaching home-readiness (150min) was mainly due to a persistent symptom (58%) or a social/system problem (34%). Causes of admission were perioperative complications (80%) or social reasons (20%).Conclusion Delays in discharge are mainly due to adverse symptoms or social/system problems. Delayed discharge is associated with increased postdischarge pain, lower RNA level, and patient acceptability. Appropriate care of postoperative symptoms and system management could prevent delay in discharge and improve patient RNA level and acceptability.This work was presented in part at the 7th Congress of the Japanese Society for Ambulatory Anesthesia at Nagoya, Japan     

Bench test assessment of the new Raumedic Neurovent-P ICP sensor: a technical report by the BrainIT group

Summary. Background. In clinical practice, fiberberoptic and piezo-electric ICP probes are often used for measuring intracranial pressure (ICP). A number of similar technologies, although performing well in bench test studies, have been shown to exhibit unacceptable zero drift, fragility or both during trials conducted under clinical conditions. Recently, a new technology has become available, the Neurovent-P (Raumedic AG+CO, Raumedic, Germany). As a pre-requisite for a clinical trial, we have conducted and report on bench test studies to confirm the manufacturers long term zero-drift performance for this technology.Method. In a test rig static tests (recording of 20mmHg pressure) and dynamic tests, ranging from 5 to 50mmHg have been performed.Findings. 10 ICP probes have been tested for a total of 60 days. All the catheters, after the connection with the ICU monitor displayed a static pressure of 0±1mmHg and did not required pre-insertion alteration. At five days, mean zero drift was 0.6±0.9mmHg. Overall, zero drift ranged from 0 to 2mmHg. At a fixed static pressure of 20mmHg, the mean recorded value was 20.6±0.8mmHg, ranging from 19 to 23mmHg. A regression analysis of the relationship between the applied pressure and the recorded pressure during the dynamic tests of the 10 catheters yielded a correlation coefficient R² of 0.997. Applying the Altman and Bland method to assess the bias and confidence limits for the Raumedic catheter responses during the dynamic tests against the applied gold-standard hydrostatic column pressures, the average bias of –0.66±0.85mmHg, with 95% CLs of –2mmHg and 1mmHg.Conclusions. Mean zero drift, after five days, was very small and long-term continuous recording of a stable pressure was very precise. The response at dynamic tests, i.e. the changes of pressure in a wide range, was excellent. The average bias of the Raumedic catheter compared with the hydrostatic column is very small. After this bench test, the next and most critical step will be to conduct a trial of this promising technology under more demanding clinical environment.     

The effects of calcium antagonists on EEG,evoked potentials and neurologic recovery after complete global brain ischemia for 15 minutes in dogs

The effects of three calcium antagonists on the recovery from neurologic damages after complete global brain ischemia were examined by evaluating the change of a electroencephalogram (EEG), evoked potentials (EP) and a neurologic recovery score (NRS) in dogs. Fifteen minutes global brain ischemia was achieved by occluding the ascending aorta and the caval veins. Nicardipine (NC), flunarizine (FL) and diltiazem (DL) were administered with continuous infusions for three days after the ischemia. The EEG-EP scores (0:no response – 6:normal) 3hr after the ischemia were 1.4 ± 0.4 (mean ± SE) in the control, 2.2 ± 0.3 in the NC, 2.2 ± 0.4 in the FL and 2.1 ± 0.2 in the DL. There were no significant differences between the 4 groups. The survival rates on the 7th day after the ischemia were 67% (6/9) in the control, 78% (7/9) in the NC, 56% (5/9) in the FL and 89% (8/9) in the DL. No significant differences were presented between the 4 groups. The NRSs (0:death – 100:normal) on the 7th day were 40.3 ± 7.3 in the control, 59.0 ± 8.5 in the NC, 63.2 ± 9.7 in the FL and 55.7 ± 3.3 in the DL. Each treated group showed a tendency to have a higher NRS than that in the untreated control group. The NRS in all dogs treated by the Ca⁺⁺ antagonists on the 7th day was 58.7 ± 4.1, which was significantly higher than that in the control group (P < 0.05). We conclude that the continuous administration of calcium antagonists for three days after the global brain ischemia would be beneficial for the neurologic recovery.(Ono K, Iwatsuki N, Takahashi M, et al.: The effect of calcium antagonists on EEG, evoked potentials and neurologic recovery after complete global brain ischemia for 15 minutes in dogs. J Anesth 5: 114–122, 1991)     

Extravascular application of an intravascular ultrasound (IVUS) catheter during carotid endarterectomy to verify distal ends of stenotic lesions

Summary. Background. Intravascular ultrasound (IVUS) has been developed initially for intravascular imaging of coronary arteries to investigate vascular structures. We applied the IVUS catheter extravascularly to the cervical carotid arteries to obtain intra-operative ultrasound images during carotid endarterectomy (CEA). Intra-operative assessments of the distal ends of the stenotic lesions as well as pathological vascular structures are important, not only for exposing the lesions sufficiently but also for placing the shunt system safely.Method. An IVUS catheter (3.2 French/30MHz) was intra-operatively applied close to the outer surface of the cervical carotid arteries during CEA. Ultrasound transection vascular images were obtained in 33 consecutive patients (30 males and 3 females) with a mean age of 66.5 years.Findings. In 32 of 33 cases, extravascular application of IVUS catheter before making arteriotomies correctly depicted the distal ends of the internal carotid artery (ICA) stenotic lesions as a thin layer of vascular wall [0.64±0.16mm (mean±SD) compared with 1.66±0.42mm for carotid plaque] with intravascular blood flow. Based on the IVUS findings, we were able to adequately expose the normal ICA portion distal to the stenotic lesion before making the arteriotomy even in cases with stenotic lesions at very high positions, and to insert shunts safely. Furthermore, the properties of lesions and blood flow were also verified. However, it was difficult to examine the far vascular wall.Conclusions. Extravascular application of IVUS catheter is efficient for intra-operative evaluation of the distal end of the stenotic lesion especially in cases with stenotic lesions at very high positions and cases in whom pre-operative angiograms did not clearly demonstrate the distal end. The findings also demonstrate the properties of lesions and completeness of CEA.     

Cyclic alteration in the anticonvulsant effect of nitrous oxide in rats

The anticonvulsant action of nitrous oxide and its time course were studied in rats. Bicuculline, a GABA-receptor antagonist, was administered intravenously at a rate of 0.2mg·kg^–1·min^–1 during exposure to air (n = 60) or 75% nitrous oxide in oxygen (n = 80). The convulsant dose of bicuculline was determined. The rats were divided into subgroups according to the duration of exposure to air or nitrous oxide, from 0 to 120min at 15min intervals. Although the convulsant dose of bicuculline was consistent in the air group (1.03 ± 0.06mg·kg^–1, mean ± SEM), it showed two peaks at 30- and 90min exposures to nitrous oxide. The threshold dose in the nitrous oxide group was significantly higher than in the air group at only 15- and 30min exposures (1.50 ± 0.16, 2.15 ± 0.25mg·kg^–1, respectively, P 0.05). We conclude that nitrous oxide has an anticonvulsant action against bicuculline-induced seizure, and that a cyclic nature exists in its action.(Shingu K, Osawa M, Mori K: Cyclic alteration in the anticonvulsant effect of nitrous oxide in rats. J Anesth 4: 309–312, 1990)     

Enhancement of lidocaine-induced epidural anesthesia by deoxyaconitine in the rabbit

Purpose.Aconiti tuber has been used in traditional Oriental medicine to alleviate pain. The antinociceptive property of aconiti tuber is due to the action of its extracted alkaloids such as deoxyaconitine. The purpose of this study was to investigate the effect of epidural deoxyaconitine on epidural lidocaine anesthesia. Methods.Five adult rabbits were used. Three different combinations of drugs were injected into the epidural space, in the following order: first (combination A), 1.5ml of 2% lidocaine; second (combination B), 1.5ml of 2% lidocaine and 150µg deoxyaconitine; and third (combination C), 3mg nor-binaltorphimine followed by 1.5ml of 2% lidocaine and 150µg deoxyaconitine 30min later. The latency of onset and the duration of three end-points (sensory loss in the tail, loss of weight-bearing ability, and flaccid paresis of hind limb) were measured. Results.Onset times for the three end-points were not changed by deoxyaconitine or by nor-binaltorphimine. The duration of sensory loss was 27.0 ± 2.7min, the duration of loss of weight-bearing ability was 33.0 ± 2.7min, and the duration of flaccid paresis was 21.0 ± 4.2min in the combination A group. In the combination B group, deoxyaconitine extended the time of sensory loss by 80%, the time of loss of weight-bearing by 50%, and that of flaccid paresis by 60% compared with the combination A group. In the combination C group, this phenomenon was partially antagonized by pretreatment with nor-binaltorphimine, a -opioid antagonist. Conclusions.Based on our observations, deoxyaconitine enhanced epidural lidocaine anesthesia in the rabbit, and this effect seemed to be partly mediated by -opioid receptors.     

Osteosarcoma of the Hand and Forearm: Experience of the Cooperative Osteosarcoma Study Group

Background Osteosarcoma is extremely rare in the hand and forearm. Therefore, only limited data are available for planning treatment or predicting the outcome and prognosis of osteosarcoma in the peripheral upper extremity.Methods Epidemiological, clinical, and histopathologic data were analyzed in 39 patients with osteosarcoma of the forearm or hand who were enrolled in studies of the Cooperative German-Austrian-Swiss Osteosarcoma Study Group from 1977 to December 2000. In patients with high-grade osteosarcoma, the treatment entailed surgical resection in combination with chemotherapy, whereas patients with low-grade osteosarcoma underwent only surgery.Results The 5-year overall survival rate among the 33 patients with high-grade central osteosarcoma of the distal upper extremity was 86.2%±6.4%. The 5-year event-free survival rate was 65.4%±9.6%. Five of the eight patients with secondary metastases were in remission at the time of analysis. Four patients died of their disease, and two patients died of chemotherapy-related complications. The mean overall survival rate was 88.0%±6.5% in patients treated by wide or radical tumor resection and was 75.0%±21.7% in patients with nonwide margins of resection. Whether amputation or local resection was performed had no significant influence on the prognosis. All six patients whose osteosarcoma was not classified as high-grade central osteosarcoma were in remission at the time of analysis.Conclusions The results demonstrate a remarkably high survival rate for patients with high-grade osteosarcoma of the hand and forearm and confirm that multiagent chemotherapy in combination with wide excision is a highly effective treatment for this malignant tumor.Published by Springer Science+Business Media, Inc. © 2005 The Society of Surgical Oncology, Inc.     

Hepatic resection for colorectal metastases in the caudate lobe of the liver

Although hepatic resections for colorectal metastases have become established procedures, there is still only a small number of reports of hepatic resections for such metastases in the caudate lobe. From 1993 to 2001, seven patients underwent eight hepatic resections for colorectal metastases in the caudate lobe at our department. The patients were five men and two women, and their ages were from 53 to 73 years. The ratio of synchronous to metachronous liver metastases was 2:5. Solitary metastasis was observed in one patient. One patient with a metastasis in the Spiegel lobe and three patients with metastasis in the caudate process underwent partial resection of the site. The other patients underwent resection of the Spiegel lobe (two times), resection of the right-sided caudate lobe, and total caudate lobe resection. The mean (±SE) operative time was 315.9 ± 30.6min. Mean intraoperative blood loss was 1325.9 ± 421.1ml, and mean postoperative hospital stay was 21 ± 3.7 days. One patient, who underwent sigmoidectomy and hepatectomy as an emergency operation due to ileus, experienced wound infection. No patient died within 12 months after the surgery. Five patients were alive at 24 months, and three at 36 months. The outcome of these patients encourages us to continue performing hepatic resection for colorectal metastases in the caudate lobe, as it is assumed to be a safe and effective procedure.     

Image fusion of MR images and real-time ultrasonography: evaluation of fusion accuracy combining two commercial instruments,a neuronavigation system and a ultrasound system

Summary Objective. The aim of our study was to evaluate MRI/Ultrasonography fusion accuracy depending on three ultrasonographic parameters.Method. An ultrasonography and MRI compatible model was created, consisting of a plastic box, which contained 3 objects. MRI scans were performed with 128 sagittal slices. The objects were segmented and 3D reconstructions were created. A special ultrasound adapter with 3 reflective markers was fixed to the ultrasound probe. Thus, the probe could be tracked by the navigation system (Vector Vision², BrainLab, Heimstetten, Germany) and the segmented shape of the 3D-objects obtained from the MR images were overlaid onto the ultrasound display (Elegra, Siemens, Erlangen, Germany). The dependency of fusion accuracy on different depth of ultrasound display, different distances between probe and objects and different angles between the axis of the ultrasound probe and the centre of the spheres was evaluated. 435 single measurements were performed.Findings. Overall fusion accuracy was 1.08mm±0.61mm (mean ± standard deviation) for spheres and 1.6mm±1.1mm for arrow heads. If the ultrasound probe was directed more tangentially to the surface of the spheres the fusion became increasingly inaccurate (P<0.05). Fusion accuracy decreased the more distant the US probe was held to the object (P<0.05). Different depth of ultrasound display had no significant effect on fusion accuracy.Conclusions. Highly accurate fusion of MR images and real-time ultrasonography could be achieved. However, careful interpretation of the fused data is necessary, when different angles and distances of the US probe to the object are concerned.     

Time-level relationship for nitric oxide and the protective effects of aminoguanidine in experimental spinal cord injury

Summary. Background. The secondary injury process following spinal cord trauma has been shown to involve different mechanisms such as excessive release of excitatory amino-acids, and induction of free radical induced lipid peroxidation. In this experimental study, the time-level relationship of the nitric oxide and the neuroprotective effects of aminoguanidine were investigated in a rat spinal cord trauma model.Methods. The experiments were performed on 63 Wistar albino rats divided into three groups; sham-operated control (Group 1), trauma created control (Group 2) and aminoguanidine group (Group 3). In groups 2 and 3, spinal cord trauma was produced at thoracic level by using weight the drop technique (at a severity of 50gr-cm). After the trauma, the rats in Group 3, received an intraperitoneal injection of 100mg/kg aminoquanidine twice a day for 3 days. The effects of the injury and the efficacy of aminoguanidine were determined based on biochemical parameters (lipid peroxidation and nitric oxide levels in tissue), and on light microscopy findings in cord tissue collected at different times post-injury. Biochemical parameters were performed one hour, three and five days after injury. Functional recovery was assessed at 3, and 5 days after cord trauma with the inclined-plane technique and Tarlovs motor grading scale.Findings. Although there was no statistically significant difference at the 1^st hour, the values of the tissue nitric oxide in trauma created controls were 42% higher on the 3^rd day and 40% higher on the 5^th day when compared with those in sham controls. The levels of the tissue lipid peroxidation in trauma created controls were 88% higher at the 1^st hour and 52.8% higher on the 5^th day when compared with shame controls, but there was no meaningful difference on the 3^rd day. In the trauma created control group, the mean motor function scores decreased to 1.16±0.40 and to 1±0 on the 3^rd and 5^th day, respectively. In this group the mean values of the inclined plane were 39.16±2.04 on the 3^rd day and 37.91±1.02 on the 5^th day. No statistically significant difference was observed in both tissue lipid peroxidation and nitric oxide levels for all time points between the aminoguanidine group and the sham-operated controls (p>0.01). The motor function scores were observed as 2.16±0.40 on the 3^rd day and as 3±0 on the 5^th day in aminoguanidine group. These values were significantly higher than the trauma created controls (p<0.01). Aminoguanidin treatment also improved the inclined plane performance of the rats; In this group, the mean values of the inclined plane scores were 44.58±2.92 and 52.91±1.88 on the 3^rd and 5^th days, respectively. These values were significantly higher than the trauma created controls (p<0.01).Interpretation. This study shows that the nitric oxide level does not increase in the spinal cord tissue during the first hour after the spinal cord trauma. It increases significantly in the spinal cord tissue not only three days but also five days following the trauma. Aminoguanidine treatment, which is started just after the trauma, can prevent both the nitric oxide production and lipid peroxidation in spinal cord tissue and it can improve the functional status of the animals. In this respect, aminoguanidine may have a potential role in the treatment of acute spinal cord injury.