Interscalene block using ultrasound guidance: impact of experience on resident performance.

BACKGROUND: We evaluated the weekly progress of anesthesiology residents performing an interscalene block with ultrasound guidance (UG) for block success rates and for the specific time intervals: (i) time to image the brachial plexus and (ii) time from insertion of the block needle until motor stimulation occurred. Our primary objective was to characterize the influence of experience over the course of the regional anesthesia rotation on the performance of a UG interscalene block by anesthesiology residents. METHODS: Residents conducted an interscalene block with UG under the supervision of attending anesthesiologists experienced in this technique. Block efficacy, time intervals required to perform the block, and acute complications were recorded. We compared success rates over the course of the rotation, and analyzed process time data with respect to trainee level of experience, week of the trainee rotation, and patient body habitus. RESULTS: Twenty-one trainees conducted 222 blocks over a consecutive 7-month period. Block success rate was 97.3%, and did not change significantly over the course of the 4-week rotation. Total block time and imaging time significantly decreased over the 4-week rotation, while the needle insertion-to-stimulation time did not change. Slower imaging time was predicted by obesity. CONCLUSION: The success rates for a UG interscalene block provided by supervised residents were initially high, and remained so throughout the 4-week rotation. Trainees required less time to image the nerves and to perform the block over the course of the rotation.

Routine evaluation of the cervical spine in head-injured patients with dynamic fluoroscopy: a reappraisal.

BACKGROUND: The mechanism for clearing the cervical spine in patients with altered mental status remains controversial. Recommendations have ranged from removal of the cervical collar after 24 hours in patients with normal radiographs, to indefinite immobilization in a cervical collar, and recently cervical flexion-extension examinations using dynamic fluoroscopy. The purpose of this study was to evaluate the efficacy and safety of dynamic fluoroscopy flexion-extension examinations in identifying ligamentous cervical spine injury and clearing the cervical spine in patients with altered mental status after trauma. METHODS: Patients with a Glasgow Coma Scale score < 13 for greater than 48 hours after admission and normal cervical spine radiographs were candidates for fluoroscopic evaluation. The protocol required visualization of the entire cervical spine, through T1, through full extension and flexion under the direct supervision of a radiologist. Oblique fluoroscopic views were obtained, as necessary, to visualize the cervicothoracic junction. Demographic data, fluoroscopy time, total time per study, true and false positives and negatives, and complications were recorded. RESULTS: From July 1992 through December 1999, fluoroscopic examinations were performed on 301 patients. There were 297 true-negative examinations, 2 true-positive examinations (stable injuries), 1 false-negative examination, and 1 false-positive examination. The incidence of ligamentous injury identified by fluoroscopy in this study was 2 of 301 (0.7%). Unstable cervical spine ligamentous injuries were identified in only 0.02% of all trauma patients. One patient developed quadriplegia when fluoroscopic evaluation was performed after two protocol violations. CONCLUSION: Unstable cervical spine ligamentous injury without fracture is a rare occurrence. The cervical spine may be cleared after a normal cervical spine series (plain radiograph and computed tomographic scan) as recommended in the 1998 Eastern Association for the Surgery of Trauma guidelines. If dynamic fluoroscopy is to be used, adherence to the protocol, including review of the cervical spine radiographs before fluoroscopy and visualization of the entire cervical spine, C1-T1, is mandatory to ensure patient safety.

Histological characteristics and expression of acidic and basic fibroblast growth factor genes in intracerebral xenogeneic transplants of human glioma cells.

Eleven athymic nude rats had stereotactic intracerebral inoculation of cells from one of three established human glioma cell lines (A172, A1207, and A1235). The implants grew progressively in 9 of 11 instances, which led to spontaneous death of the host in 14 to 37 days. For comparison, two Sprague-Dawley normal albino rats were implanted with the rat C6 glioma cell line. One rat died at 14 days, and the other was killed at Day 16. The human glioma cells developed into partially (A172, A1235) or totally (A1207) circumscribed tumor masses. Invasion, when present, was manifested as infiltrating prongs of cells rather than as individual cell infiltration. The growth of the human glioma cells was accompanied by a small zone of surrounding edema and marked central necrosis. These features were not encountered in the C6 implants. Inflammatory changes were minimal to nonexistent in all cases. All tumor lines produced internal cerebral herniation and neuraxis spread with implants seeded throughout the ventricular system, often associated with ventricular dilation. In situ hybridization, by the use of isotopic and nonisotopic detection methods, was used to study the cellular expression of the acidic fibroblast growth factor and basic fibroblast growth factor genes in A172 glioma xenografts. The expression of these genes was not seen in normal rat brain, but the genes were selectively overexpressed by the glioma cell implants, with especially high signal in the tumor periphery.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical course and diagnosis of migraine headaches in hydrocephalic children.

Headaches, vomiting and altered sensorium can be seen in patients with migraines as well as in patients with shunt malfunctions. This is a report of 10 patients with hydrocephalus and CSF shunts who presented with headache, vomiting, varying degrees of impairment of consciousness, and coma. Various diagnostic considerations were made: shunt malfunction, slit ventricle syndrome and low pressure (overshunting). Repeated operative procedures were performed in all. 7 of 10 patients had a family history of migraines when the diagnosis of migraine was entertained, 8 patients improved on propranolol therapy, 1 failed with this therapy but responded to verapamil. In the remaining 2 patients, after a transient response to propranolol, compartmentalized hydrocephalus became obvious and improvement followed with shunt procedures. It is concluded that in those patients with hydrocephalus and small ventricles on neuroimaging and a family history of migraines, and in the face of documented adequate shunt function, the diagnosis of migraines be entertained before further operative interventions.

Migraine headaches in hydrocephalic children: a diagnostic dilemma.

Headaches, vomiting, and altered sensorium can be seen in patients with shunt malfunction as well as in those with migraines. We report five cases in which children with hydrocephalus and CSF shunts presented with a variety of recurring symptoms, including headache, vomiting, impairment of consciousness to the point of coma, and, in one patient, decerebrate posturing. Various diagnoses were entertained: shunt malfunction, slit ventricle syndrome, and low pressure (overshunting). Repeated procedures were carried out in all patients, including shunt taps, multiple shunt revisions, and a subtemporal decompression. When the diagnosis of migraine was considered, four patients improved on propranolol therapy; one failed this therapy but responded to verapamil. We conclude that in patients with hydrocephalus and repeated bouts of symptoms such as headaches, vomiting, and impairment of consciousness and in the case of documented, adequate shunt function, the diagnosis of migraine be entertained before further operative intervention is undertaken.

Monoclonal antibodies: prospects for specific immunotherapy for gliomas.

Monoclonal antibodies produced by hybrids of lymphoid cells can be raised against cancer cells. These antibodies can be used to detect certain cancers, and some monoclonals bind with relative selectivity to glioma-associated antigens. Various laboratories are studying the radiolocalization of human glioma antigens in tumor cells transplanted into animals, and this imaging technique is also being tested in patients. Methods have been developed to promote passage of these antibodies across the blood-brain barrier, and thereby, to increase their uptake in tumors. Either alone or in conjunction with macrophages, cytotoxins, or radiosensitizers, these antibodies may offer a high degree of selective tumor destruction with relative sparing of normal brain.

Developmentally regulated lectin from embryonic chick pectoral muscle. Purification by affinity chromatography.

A lectin, whose specific activity in soluble extracts of embryonic chick pectoral muscle increases strikingly between 8 and 16 days of development, has been purified by affinity chromatography on derivatized Sepharose 4B coupled to p-aminophenyl-beta-D-lactoside. After affinity chromatography the lectin is pure except for minor contamination with another protein possibly representing a second muscle lectin. The latter can be completely removed by preparative isoelectric focusing. The purified lectin has an apparent molecular weight of 30,000 and an apparent subunit molecular weight of 15,000. Its isoelectric point is 4.0. The most potent saccharide inhibitors tested were thiodigalactoside and lactose. An antibody has been raised to the pure lectin. Studies with this antibody indicate that the lectin is present both on the surface of and within myoblasts.

Lectin activity in embryonic chick muscle: developmental regulation and preliminary purification.

Soluble extracts of embryonic chick pectoral muscle contain lectin activity. This activity is assayed by agglutination of trypsin-treated, glutaraldehyde-fixed rabbit erythrocytes, and is blocked by specific saccharides such as thiodigalactoside and lactose. Lectin activity of the muscle extracts increased at least 1 order of magnitude between 8 and 16 days of chick embryo development, as the pectoral muscle differentiated. Preliminary purification was achieved by affinity chromatography on Sepharose 4B deprivatized with either asialo-bovine glycoprotein, or p-aminophenyl beta-D-thiogalactopyranoside as the ligand.

Agglutinin from Limulus polyphemus. Purification with formalinized horse erythrocytes as the affinity adsorbent.

We have purified an agglutinin from the hemolymph of Limulus polyphemus about 1500-3000-fold by adsorption to formalinized horse erythrocytes, elution with N-acetylneuraminic acid and subsequent fractionation on Sephadex G-200. Recovery was in the range of 50 percent. On ultracentrifugation the agglutinin behaves as an homogenous protein with a molecular weight of about 460 000. On polyacrylamide gel electrophoresis of the dissociated protein in sodium dodecylsulfate we found a single prominent diffuse band with an apparent molecular weight of 22 000 plus or minus 2000. This band contained carbohydrate as determined by periodic acid-Schiff staining. The intensity of staining compared with standards suggested a carbohydrate content of less than 4 percent. The protein contains a preponderance of acidic amino acids and has an isoelectric point of 4.83.5 residues per 1000 of glucosamine were detected on amino acid analysis. Agglutination of formalinized horse erythrocytes by the purified protein is inhibited not only by N-acetylneuraminic acid but also by D-glucuronic acid; but not by a number of other monosaccharides. D-Glucuronic acid may be used in place of N-acetylneuraminic acid as the eluting sugar in the purification procedure.