Vitamin E protects human skeletal muscle from damage during surgical ischemia-reperfusion

Idiopathic epidural spinal lipomas are rare: only 13 cases have been described in the literature. We report a further case in an obese patient without known etiological factors. Diagnosis of epidural lipomatosis was performed by MRI. Weight reduction was obtained by conservative treatment, reserving surgery in case symptoms did not disappear. Of the 8 obese patients with idiopathic epidural spinal lipomatosis described in the literature, 3 were treated conservatively, with complete regression of symptoms in 2 cases, partial in the other one. In our patient, the radicular symptomatology disappeared once he had lost weight.     

Testing an implantable intraspinal drug delivery device in the ewe

OBJECTIVE: The authors report the use of multiple implanted intraspinal port and catheter systems per test animal to study the in vivo functional characteristics and reliability of a new implantable spinal drug delivery port system. METHODS: Four ewes were each implanted with two epidural and one subarachnoid silicone elastomer catheters at the lumbar level. Each catheter was connected in series to one of three Therex filtered spinal delivery ports implanted subcutaneously in a similar grid pattern in each ewe to facilitate percutaneous identification. Saline (2 ml) was injected 3 times weekly in each port. The ease of injection and behavioral responses were recorded for 207-213 days of implantation until sacrifice/necropsy. RESULTS: All ports functioned reliably during the study. However, injection through two of the four subarachnoid catheters resulted in behavioral withdrawal responses intermittently. This behavioral pattern was much less common after epidural port injections. All four subarachnoid and four of eight epidural port and catheter systems were tested with local anesthetic just before sacrifice. Motor block was observed in three of four subarachnoid and three of four epidural port and catheter systems tested. Integrity of the other four epidural ports was tested by injection of methylene blue at sacrifice. This dye did not distribute in the epidural space in one of the latter four epidural ports (not local anesthetic tested) because of a concentric fibrotic reaction about the catheter. Similar fibrotic reactions surrounded the catheters that failed a functional test with local anesthetic. CONCLUSIONS: The implantable intraspinal port system tested functions reliably under repetitive percutaneous access. However, filtering such ports, though desirable to prevent entry of debris into the spinal canal, did not eliminate pericatheter chronic subarachnoid and epidural reaction. The number of test animals required to test 12 ports chronically was reduced by two-thirds without undue trauma to the individual test subject. Chronic percutaneous injection of an implanted subarachnoid system is feasible but may be associated with behavioral effects similar to that seen with chronic epidural systems. Fibrosis around chronic silicone catheters limited functional utility in one-fourth of the implanted test systems. Further study of the potential reactivity of chronic epidural and subarachnoid catheters is indicated.     

Perinatal mortality after epidural analgesia

A retrospective survey has been carried out of 6442 births during 1973-1974 in Cardiff. Lumbar epidural block had been administered to the mothers of 13-7% (885) of the births, the principle indication being relief of pain. In the management of the mother special emphasis was laid upon avoiding aorto-caval compression. The perinatal mortality associated with epidural block (14-8 per 1000) was not significantly different from that after other forms of analgesia (19-2 per 1000). There were less first week deaths in babies weighing less than 2-5 kg after epidural block (0 of 45) than in those who had other methods of pain relief (41 of 414) (P = 0-023). The choice of maternal medication did not influence the perinatal mortality rate of the immature baby, but there is a positive but non-significant, trend in favour of epidural block in the premature baby. This improvement in mortality could simply be related to the increased use of forceps delivery associated with epidural block. A controlled trial of epidural block is therefore indicated in the management of the premature fetus. In babies over 2-5 kg, or, those who were immature, epidural block was not associated with a reduction or increase in perinatal mortality.     

Epidural fentanyl produces labor analgesia by a spinal mechanism

BACKGROUND: The purpose of this study was to determine if epidural fentanyl produces analgesia in laboring patients by a primary spinal or supraspinal action. METHODS: Fifty-four parturients were randomized to receive epidural 0.125% bupivacaine plus one of three treatments: epidural saline-intravenous saline, epidural fentanyl (20 microg/h)-intravenous saline, or epidural saline-intravenous fentanyl (20 microg/h). The study treatments were administered by continuous infusion, whereas epidural bupivacaine use was patient controlled. RESULTS: Epidural bupivacaine use was significantly reduced by epidural (11.5+/-4.6 ml/h) but not by intravenous fentanyl (15.9+/-4.5 ml/h) compared with saline control (16+/-5.9 ml/ h). Analgesia characteristics and side effects were similar among groups. CONCLUSIONS: Low-dose epidural infusions of fentanyl produce labor analgesia by a primary spinal action.     

Deliberate hypotensive epidural anesthesia for patients with normal and low cardiac output

The use of hypotensive anesthesia is contraindicated in patients with ventricular dysfunction, even though afterload reduction often improves ventricular performance. The purpose of this study was to prospectively assess systemic hemodynamic responses to deliberate hypotension with epidural anesthesia in patients with chronic left ventricular dysfunction. Hemodynamic measurements were performed in 29 patients undergoing total hip arthroplasty under deliberate hypotensive epidural anesthesia using low-dose intravenous epinephrine infusion to maintain mean arterial pressure (MAP) at 50-60 mm Hg. Intraoperative MAP decreased from 100 +/- 16 to 56 +/- 9 mm Hg by 30 min after epidural injection (P < 0.0005). Concurrently, cardiac index (CI) increased from a preanesthetic baseline value of 2.9 +/- 0.5 to 3.3 +/- 0.9 L.min-1.m-2 at 30 min (P < 0.005) after epidural injection and stroke volume index (SVI) increased from 41 +/- 8 to 50 +/- 14 mL.beat-1.m-2 30 min after epidural injection (P < 0.005). Heart rate and central venous and pulmonary artery diastolic pressures were maintained under hypotension with epidural anesthesia in all patients. During deliberate hypotension with epidural anesthesia, patients with a history of congestive heart failure or low preanesthetic CI (< or = 2.5 L.kg-1.m-2) increased their CI and SVI into the normal range. There were no significant perioperative complications in either of these groups. Hypotensive epidural anesthesia can be used successfully in patients with low cardiac output from ventricular dysfunction undergoing total hip arthroplasty.     

What is your diagnosis? Leiomyosarcoma of the cecum

Epidural hematoma is a rare but serious neurological complication of epidural anesthesia. We report the case of a 61-year-old man with squamous cell carcinoma of the lung who suffered an epidural hematoma after undergoing right double lobectomy. Before anesthetic induction an epidural catheter was inserted to the D5-D6 space for postoperative analgesia. Surgery was without noteworthy events and the patient was extubated in the operating room; 5,000 IU of low molecular weight heparin was injected subcutaneously every 24 hours and 5 mg of methadone was provided by epidural catheter every 8 hours. After removal of the catheter three days after surgery, lumbar back pain and hypoesthesia, and weakness in both legs appeared. Epidural hematoma was suspected and treatment with 30 mg.kg-1 of methylprednisolone i.v. was started. Nuclear magnetic resonance imaging of the lumbar spine confirmed the presence of a hematoma at D6-D8. Neurologic symptoms improved in the following hours and additional surgery was not required. The patient was released without neurological symptoms 10 days after lung surgery. We discuss the prevalence, etiology and treatment of epidural hematoma related to epidural anesthesia.     

Posterior lumbar epidural fat as a functional structure? Histologic specificities

STUDY DESIGN: A topographic and histologic study was done to describe the location of the lumbar epidural fat and to find potential tissular specificities. OBJECTIVES: To search for possible histologic characteristics of posterior lumbar epidural fat, which so far has been described as semifluid tissue, and to determine whether posterior lumbar epidural fat is not a simple incidental tissue. SUMMARY OF BACKGROUND DATA: The lumbar epidural fat on two fetuses was studied. In adults, subcutaneous fat and posterior lumbar epidural fat were taken from seven corpses. The authors obtained 13 posterior lumbar epidural fat pads (two at L1-L2, three at L2-L3, six at L3-L4, and two at L4-L5) and four subcutaneous fat pads. METHODS: The authors studied abdominal axial histologic sections in two fetuses, histologic multiplanar sections in seven adults, and semithin sections in four adults of posterior lumbar epidural fat and subcutaneous fat. RESULTS: Fetal distribution of epidural fat was circumferential. Adult epidural fat distribution was limited to the posterior part of the vertebral canal and located at the disc level. Fascicles of connective tissue were less numerous and thinner in posterior lumbar epidural fat than in subcutaneous fat. Organized sliding spaces were found in the posterior epidural fat ped. CONCLUSIONS: Posterior lumbar epidural fat is not a simple incidental tissue and shows specific histologic features: sliding spaces and rarefaction of connective tissue that could explain semifluid features of the tissue. These characteristics suggest a functional role of posterior epidural fat in the lumbar spinal unit.     

Epidural opioid analgesia after caesarean section: a comparison of patient-controlled analgesia with meperidine and single bolus injection of morphine

The quality of analgesia, patient satisfaction and incidence of side effects following a single bolus of epidural morphine were compared with patient-controlled epidural analgesia (PCEA) with meperidine during the first 24 hr after elective Caesarean section. Seventy-five women were randomly assigned to three equal groups. Group I received 30 mg epidural meperidine after delivery and PCEA with meperidine; Group 2 received 3 mg epidural morphine after delivery and PCEA with saline in a double-blind fashion. Group 3 received 3 mg epidural morphine after delivery without saline PCEA. Visual analogue pain scores (VAS) were higher with PCEA meperidine from 8-16 hr post-operatively (P < 0.05) than in both epidural morphine groups. Two patients in Group 1 and one in Group 3 required supplemental parental analgesia. The incidence of nausea was 16% in Group 1, compared with 52% in Group 2 and 56% in Group 3 (P < 0.01). Pruritus occurred in 24% of Group 1 patients, 84% of patients in Group 2 and 68% of patients in Group 3 (P < 0.001). Forty-six percent of patients in Group 1 were very satisfied with pain management, compared with 77% in Group 2 and 79% in Group 3. Nurse workload was higher in the PCEA study groups than in Group 3 (P < 0.05). A single bolus of epidural morphine provides superior analgesia and satisfaction at low cost, but with a higher incidence of nausea and pruritus than PCEA with meperidine.     

A comparison of the sensitivity of epidural and myogenic transcranial motor-evoked responses in the detection of acute spinal cord ischemia in the rabbit

Monitoring motor-evoked responses to transcranial stimulation (tc-MERs) provides information about the functional status of the spinal cord during operations that pose the risk of spinal cord ischemia. Responses can be recorded from the epidural space (epidural tc-MERs) or from muscle (myogenic tc-MERs). In this study the relative sensitivity of epidural and myogenic tc-MERs to acute spinal cord ischemia was compared. Spinal cord ischemia was produced by infrarenal aortic balloon occlusion in nine anesthetized New Zealand White rabbits. Tc-MERs were evoked by transcranial electrical stimuli applied to the scalp. Responses were recorded from the lumbar epidural space and from the soleus muscle, and the effect of aortic occlusion was assessed. The peak-to-peak amplitude of the direct wave of the epidural response decreased gradually during aortic occlusion in eight animals and increased in one. The median (10th to 90th percentiles) time to a 50% reduction in amplitude was 11.3 (3-22) min. In contrast, myogenic responses disappeared within 2 min after the start of occlusion in all animals. Lower extremity ischemia as a cause of changes in myogenic tc-MER amplitude was excluded by ligating the right femoral artery and demonstrating that myogenic responses were preserved for 30 min, before occluding the aorta. We conclude that myogenic responses are more sensitive to acute spinal cord ischemia than epidural responses. The rapid detection of spinal cord ischemia with transcranial myogenic motor-evoked responses could be of clinical use in assessing the adequacy of spinal cord blood flow during operations where the spinal cord is at risk.     

Multicomponent intravenous and epidural anesthesia in aorto-coronary bypass surgery

The influence of epidural anesthesia (CEA) on clinical manifestations, cortisole and adrenocorticotropic hormone (ACTH) level, central hemodynamic values during aorto-coronary bypass surgery (ACBS) in 56 patients aged 42-68 years with preserved functional capacity of the myocardium was studied. Catheterisation of the epidural space was carried out in the evening before the operation according to the standard method at the level of T4-T5 with the use of disposable epidural set. During the procedure before perfusion 2% solution of lidocaine 3.8 +/- 0.2 mg/kg was introduced in epidural space (taking into account test-dose) as a bolus in 3-4 motions. The dose of local anesthetics for infusion was selected separately for each individual case with due regard for hemodynamic values. During artificial circulation additionally local anesthetic was introduced as a bolus, the dose being 4.7 +/- 0.8 mg/kg. At the end of the operation morphine (0.061 +/- 0.001 mg/kg) was introduced. It was established that combined application of intravenous and epidural anesthesia represents highly effective method of anesthesia in aorto-coronary bypass surgery. According to clinical course data, cortisone and ACTH blood contents and hemodynamic parameters, EA provides adequate anesthesia, promotes stabilization of hemodynamic values and creates functionally more advantageous conditions for the myocardium in patients with CHD during aorto-coronary bypass operation. Anesthesiologic aid with the use of EA promotes reduction of intravenous anesthetics expenditure, earlier waking up of the patients in postoperative period and decrease in duration of postoperative artificial lung ventilation.     

Chronic catheterization of the epidural space in rabbits: a model for behavioural and histopathological studies. Examination of meptazinol neurotoxicity

A technique of epidural catheterization in rabbits is described. Twelve albino rabbits received a totally implanted epidural catheter system. The system was implanted surgically, and the functioning of the system tested for a period of 3 months. X-ray examinations following epidural contrast injections showed a distribution up to Th4 following 1.5 ml and Th8-9 following 1.0 and 1.25 ml. Epidural injection of lidocaine throughout the study period proved the system to be functioning for all 3 months. Another 12 rabbits were included for the neurotoxicological examinations following epidural catheterization, without any injections (three rabbits), epidural injections of saline (four rabbits) and meptazinol (five rabbits) once a day for 14 days. Histopathological examinations showed a fibrous cocoon, at the tip of the catheter, in all rabbits. In the group of rabbits which did not receive any injections, the cocoon was slightly infiltrated with leukocytes and local depression of the spinal cord was observed in one rabbit. In the saline-injected group this infiltration was more pronounced and in one rabbit it extended into the meninges. Three rabbits showed local depression of the spinal cord and local myelopathy of the white matter in the area adjacent to the cocoon. In the group of rabbits receiving meptazinol, three out of five had local depression and myelopathy of the white matter. In this group these findings were more pronounced. In two rabbits the myelopathy extended transversely through the white matter into the grey matter of the spinal cord. The number of pathological changes in the group receiving meptazinol was significantly higher compared to the control and placebo groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

High-Resolution Infrared Fourier-Transform Spectroscopy and Rotational Constants of the nu4 Band of BrNO2

In this study, we assessed the influence of three analgesic techniques on postoperative knee rehabilitation after total knee arthroplasty (TKA). Forty-five patients scheduled for elective TKA under general anesthesia were randomly divided into three groups. Postoperative analgesia was provided with i.v. patient-controlled analgesia (PCA) with morphine in Group A, continuous 3-in-1 block in Group B, and epidural analgesia in Group C. Immediately after surgery, the three groups started identical physical therapy regimens. Pain scores, supplemental analgesia, side effects, degree of maximal knee flexion, day of first walk, and duration of hospital stay were recorded. Patients in Groups B and C reported significantly lower pain scores than those in Group A. Supplemental analgesia was comparable in the three groups. Compared with Groups A and C, a significantly lower incidence of side effects was noted in Group B. Significantly better knee flexion (until 6 wk after surgery), faster ambulation, and shorter hospital stay were noted in Groups B and C. However, these benefits did not affect outcome at 3 mo. We conclude that, after TKA, continuous 3-in-1 block and epidural analgesia provide better pain relief and faster knee rehabilitation than i.v. PCA with morphine. Because it induces fewer side effects, continuous 3-in-1 block should be considered the technique of choice. Implications: In this study, we determined that, after total knee arthroplasty, loco-regional analgesic techniques (epidural analgesia or continuous 3-in-1 block) provide better pain relief and faster postoperative knee rehabilitation than i.v. patient-controlled analgesia with morphine. Because it causes fewer side effects than epidural analgesia, continuous 3-in-1 block is the technique of choice.     

Effect of anesthetic methods on hemodynamics and metabolic changes caused by hepatic ischemia and reperfusion in pigs

The effects of halothane, isoflurane and epidural anesthesia combined with isoflurane on hemodynamic and metabolic changes caused by hepatic ischemia and reperfusion were studied in 16 pigs. Hepatic arterial and portal venous blood flows were measured electromagnetically. Lactate pyruvate ratio (L/P) and arterial ketone body ratio (AKBR) were calculated as markers of hepatic aerobic metabolism. Total hepatic blood flow (THBF), cardiac output (CO) and THBF/CO showed no significant differences among three anesthetic methods in ischemic and reperfusion period. In the group with epidural anesthesia combined with isoflurane, L/P was significantly lower and AKBR was significantly higher compared with the data obtained in ischemic period. However, hepatic metabolism was severely disturbed after the reperfusion of the liver in all three groups. Especially, halothane group showed the most remarkable decrease in AKBR. In summary, epidural anesthesia will be useful for aerobic hepatic metabolism because of inhibition of the release of endogenous cathecolamines, but hepatic metabolism will not be maintained following hepatic ischemia and reperfusion.     

Safety of spinal and epidural anesthesia in parturients with chorioamnionitis

BACKGROUND AND OBJECTIVES: The safety of spinal and epidural anesthesia in patients with chorioamnionitis was explored. METHODS: A retrospective study was made of the charts of 517 parturients who had received epidural anesthesia and 14 who had received spinal anesthesia before delivery and whose placentas had subsequently been found to be positive for chorioamnionitis. RESULTS: Of the 146 blood culture results that were reported, 13 were positive. Of these 13 blood cultures, 5 had been drawn within 6 hours after placement of the epidural block, and four of the five bacteremic patients did not receive antibiotics until after the regional anesthetic was administered. One quarter (11/45) of the patients who were febrile and three quarters (174/229) of those who had leukocytosis before their block received no antibiotics before the block was placed. After the epidural block was performed, the catheter was left in place for over 24 hours in 18% (46/260) of the women who spiked a fever and in 14% (18/130) of those who exhibited leukocytosis during that period. There was no report of an epidural or spinal abscess or of meningitis in any of the women in the study. CONCLUSION: Conduction anesthesia may be safe in parturients with chorioamnionitis without prior antibiotic therapy.     

The effect of insulin-like growth factor-1 on cyclic change of tendon cell

BACKGROUND: Myoclonus is a possible side effect of opioid therapy, and have been described following systemic as well as spinal application. CASE REPORT: We report the case of a patient with metastatic carcinoma of the rectum who developed myoclonus following administration of high-dose epidural combined with iv morphine. This complication occurred with maximum daily doses of 300 mg epidurally and 80 mg intravenously and disappeared completely after dose reduction. Treatment trials are presented, the pathophysiology of the myoclonus is discussed. CONCLUSION: For treatment of opioid-induced myoclonus a dose reduction or a change of the opioid should be considered as well as symptomatic treatment with benzodiazepines or baclofen.     

Epidural spinal infection. Variability of clinical and magnetic resonance imaging findings

STUDY DESIGN: This study evaluates the magnetic resonance characteristics of spinal epidural abscesses and their associated disc space infections. OBJECTIVES: The results were correlated with history, clinical, and laboratory findings to provide guidelines for early and appropriate diagnosis of epidural spinal infections. SUMMARY OF BACKGROUND DATA: Imaging signs of spinal infections have been reported before, but not with special attention to early clinical and imaging findings. METHODS: Thirteen patients (10 men, 3 women; age range, 32-64 years) with progressive sensorimotor deficit were studied. All patients had a neurologic examination after admission and a magnetic resonance imaging scan done within the first 48 hours. In all cases, T1-weighted images before and after administration of gadolinium were obtained. T2-weighted images were acquired in eight cases as well. Ten patients subsequently underwent open surgery; in three cases, a percutaneous biopsy and drainage was performed. RESULTS: Cervical discitis was found in five patients, and thoracic discitis was seen in another five cases. Three patients had an epidural infection without a concomitant discitis. Neurologic and clinical findings varied considerably. Despite clinical signs of spinal cord involvement, a spinal cord lesion was demonstrated only once. Signal change in T2-weighted images may be the first sign of disc space infection. Because a neurologic deficit may occur before any change is visible, follow-up examinations may be required if epidural infection is suspected on clinical grounds. CONCLUSIONS: Magnetic resonance imaging is the appropriate method for diagnostic work-up of progressive neurologic deficit resulting from epidural infection.     

Respiration and circulation after total hip replacement surgery. A comparison between parenteral analgesics and continuous lumbar epidural block

The cardiopulmonary effects of two different types of postoperative analgesic regimes were compared in 31 cardiorespiratorily healthy patients subjected to total hip replacement surgery. The investigation was performed preoperatively on the morning of the day of surgery and during the first 3 days postoperatively. All patients received continuous lumbar epidural analgesia preoperatively, during surgery and up to the end of the first measurement period, which started 2.5 h after surgery. Ten patients were subseuqently given pentazocine (Fortalgesic) intramuscularly on demand for pain relief throughout the investigation, while 14 patients received 0.4% plain lidocaine (Xylocain), and seven patients 0.4% lidocaine with adrenaline (1/400,000) as a continuous lumbar epidural drip for analgesia thorughout the investigation. It was confirmed that the operative procedure itself did not significantly influence the postoperative arterial oxygenation, while the type of postoperative analgesic regimen was of considerable importance in this respect. Thus, patients given pentazocine showed a significant increase in pulmonary venous admixture, due both to an increase in true shunt and to an increase in ventilation/perfusion disturbances. This pattern of poor pulmonary function still persisted on the third postoperatively. In patients given an epidural block no significant changes in pulmonary venous admixture were noted postoperatively, and thus there was no reduction in PaO2. All patients, irrespective of the type of analgesic regimen used, had a significantly increased cardiac index and oxygen uptake postoperatively, although patients given an epidural block showed a greater increase in cardiac index, and thus a tendency towards a more hyperkinetic circulation than those given pentazocine.     

Comparison of lidocaine and saline for epidural top-up during combined spinal-epidural anesthesia in volunteers

This study was designed to determine the efficacy of saline as an epidural top-up to prolong spinal anesthesia during combined spinal-epidural anesthesia (CSEA). Eight volunteers received three separate CSEAs with intrathecal lidocaine (50 mg). After two-segment regression, each subject received either a saline (10 mL), lidocaine 1.5% (10 mL), or control sham (0.5 mL saline) epidural injection in a randomized, double-blind, triple cross-over fashion. Sensory block was assessed by pinprick and tolerance to transcutaneous electrical stimulation (TES) equivalent to surgical stimulation at the knee and ankle. Motor strength was assessed with iso-metric force dynamometry. Data were analyzed with a repeated measures analysis of variance and a paired t-test. Sensory block to pinprick was prolonged in the thoracolumbar dermatomes only by lidocaine (P < 0.05). Neither lidocaine nor saline prolonged the duration of tolerance to TES at the tested sites. Instead, saline decreased the duration of tolerance to TES by 20 and 24 min at the knee and ankle (P < 0.05). Recovery from motor block at the quadriceps was prolonged by an epidural injection of lidocaine (P < 0.05). We conclude that when 10 mL of epidural saline is administered after two-segment regression, it is an ineffective top-up and may decrease the duration of spinal anesthesia during CSEA.     

Spontaneous spinal epidural hematoma with spinal cord compression complicating plasma cell myeloma. A case report

STUDY DESIGN: A case is reported in which a patient had acute paraplegia with sensory loss caused by a spontaneous epidural hematoma that was ascribed to bleeding of pre-existing myeloma lesions of the thoracic vertebrae. OBJECTIVES: To highlight the causes of secondary epidural hematomas with special attention to pre-existing vertebral or epidural lesions. SUMMARY OF BACKGROUND DATA: There are no apparent previous reports of epidural spinal hematomas ascribed to underlying malignant diseases. Benign dysplasia, such as hemangioma or Paget's disease, has been implicated in a few cases. METHODS: A case of spontaneous dorsal epidural hematoma is reported in a patient followed up for plasma cell myeloma with osteolytic lesions in the lower thoracic spine. There was no history of major trauma or coagulation disorders. Complete loss of motor and sensory function in both lower limbs was noted, with sphincter dysfunction. Magnetic resonance imaging of the thoracic spine showed a large posterolateral epidural hematoma responsible for spinal cord compression. RESULTS: The patient failed to improve despite surgical decompression within 6 hours of symptom onset. He died 13 days later of refractory bacterial pneumonia. A large epidural hematoma adjacent to myelomatous lesions of the thoracic vertebrae was found at autopsy. CONCLUSIONS: This is the first reported case of spontaneous epidural hematoma ascribed to underlying malignant disease, with confirmation of the diagnosis by postmortem examination. Possible mechanisms include tumor-related epidural inflammation and fragility of epidural venous plexuses.     

Streptokinase in acute stroke: effect on reperfusion and recanalization. Australian Streptokinase Trial Study Group

BACKGROUND: The minimum local analgesic concentration (MLAC) has been defined as the median effective local analgesic concentration in a 20-ml volume for epidural analgesia in the first stage of labor. The aim of this study was to determine the local anesthetic-sparing efficacy of epidural sufentanil by its effect on the MLAC of bupivacaine. METHODS: In this double-blind, randomized, prospective study, 147 parturients at < or = 7 cm cervical dilation who requested epidural analgesia were allocated to one of four study groups. After a lumbar epidural catheter was placed, study participants received 20 ml bupivacaine (n = 38), bupivacaine with sufentanil 0.5 microg/ml (n = 38), bupivacaine with sufentanil 1 microg/ml (n = 33), or bupivacaine with sufentanil 1.5 microg/ml (n = 38). The concentration of bupivacaine was determined by the response of the previous patient using up-down sequential allocation. The analgesic efficacy was assessed using 100-mm visual analog pain scores, with < or = 10 mm within 30 min defined as effective. RESULTS: The MLAC of bupivacaine alone was 0.104% wt/vol (95% CI, 0.090-0.117). The addition of sufentanil at doses of 0.5 microg/ml, 1 microg/ml, and 1.5 microg/ml resulted in significant reductions (P < 0.0001) in the MLAC of bupivacaine to 0.048% wt/vol (95% CI, 0.030- 0.065), 0.021% wt/vol (95% CI, 0-0.055), and 0.009% wt/vol (95% CI, 0-0.023), respectively. CONCLUSIONS: This study showed a significant (P < 0.0001) dose-dependent reduction in the MLAC ofbupivacaine by sufentanil.