Biomedical subjects

J R Elmore

Publications and source records attributed to J R Elmore.

25 records · Page 2Linked to original sources

PubMed1991

Failure of motor evoked potentials to predict neurologic outcome in experimental thoracic aortic occlusion.

Motor evoked potential monitoring was tested as an alternative to somatosensory evoked potential monitoring in evaluating spinal cord function during thoracic aortic occlusion in dogs. Twenty-seven animals underwent 60 minutes of cross-clamping of the proximal descending thoracic aorta with (n = 18) or without (n = 9) cerebrospinal fluid drainage. Spinal cord blood flow was measured with microspheres, and neurologic outcome was evaluated at 24 hours with Tarlov's scoring system. Cerebrospinal fluid drainage improved neurologic outcome (p less than 0.05). Motor evoked potentials recorded over the lumbar spinal cord were lost in 9 of 20 dogs with ischemic cord injury and were not lost in any of the 7 dogs that were neurologically normal. Somatosensory evoked potential were lost in 19 of 20 paraplegic/paraparetic dogs and lost in 3 of 7 normal dogs (p less than 0.01). After reperfusion, motor evoked potentials returned in all nine neurologically injured dogs that lost the potentials and were still present at 24 hours. Changes in amplitude, latency, or time until loss or return of motor evoked potentials or somatosensory evoked potentials did not predict neurologic injury. Loss of somatosensory evoked potentials had a high sensitivity (95%) but had low specificity (67%) because of peripheral nerve ischemia. Loss of motor evoked potentials recorded from the spinal cord had high specificity (100%) but a low sensitivity (46%) and was therefore not a reliable predictor of neurologic injury. Return of motor evoked potentials during reperfusion did not correlate with functional recovery. Motor evoked potentials stimulated in the cortex and recorded from the spinal cord had low overall accuracy (59%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Computerized topographic brain mapping during carotid endarterectomy.

Computerized topographic brain mapping processes standard electroencephalographic data and displays it in a color map, thus simplifying interpretation. During a 2-year period, 65 carotid endarterectomies were performed with the use of brain mapping as the sole criterion for shunt replacement. Forty-three patients (66%) were found to have abnormal brain maps preoperatively. Ten patients (15%) developed ischemic changes after cross-clamping (all resolved after shunt placement). Postoperative brain maps were unchanged in 54 patients (83%) and improved in 7 patients (11%). A new, small focal abnormality was identified in 4 patients without shunts (6%), none of whom had a change in neurologic status. The overall major morbidity and mortality was 1.5%. Computerized brain mapping is a sensitive and readily interpretable means of monitoring cerebral perfusion during carotid surgery. We found the computerized electroencephalographic data to be a dependable criterion for selective shunting and for confirmation of shunt patency during carotid endarterectomy.

Adult↗

PubMed1989

Selective nonoperative management of blunt splenic trauma in adults.

The use of selective nonoperative management of blunt splenic trauma in adults is based on the undeniable benefits of this approach in children. Proper patient selection requires hemodynamic stability, lack of generalized peritoneal irritation, and minimal blood transfusion needs. Computed tomography is now used to make the diagnosis, but the decision for laparotomy is based on clinical grounds. Forty-one (87%) of 47 patients selected for nonoperative management were treated successfully without laparotomy, while the remaining 6 patients underwent delayed operations for persistent splenic bleeding. Blood transfusion requirements were significantly less in the observed group than in the operative group for patients with isolated trauma and for patients with polytrauma. There were no known missed intra-abdominal injuries and no deaths with the nonoperative approach. Analysis of our results has confirmed that nonoperative management is a safe and effective alternative to immediate laparotomy in properly selected patients and it can result in splenic salvage without the need for an operation.

Adolescent↗

PubMed1988

Renal failure and advanced atherosclerotic lesions. Salvage by vascular reconstruction.

Occlusive renal artery lesions and progressive renal failure have a dismal prognosis if not treated. We analyzed our results to determine if the risks of renal vascularization were justified based on the final outcome in such patients. Inclusion criteria were a creatinine concentration of at least 160 mumol/L (1.8 mg/dL) and one of the following angiographic findings: (1) severe (greater than or equal to 75%) bilateral occlusions, (2) total occlusion with severe (greater than or equal to 75%) contralateral occlusion, or (3) solitary kidney with severe (greater than or equal to 75%) occlusion. Thirty patients met these criteria and underwent revascularization. Six required simultaneous aortic reconstruction. The average creatinine concentration on admission was 310 mumol/L (3.55 mg/dL); this had a statistically significant improvement to 210 mumol/L (2.41 mg/dL) at discharge. There was one perioperative death (3.3%). Initially, 22 patients had improved function (creatinine concentrations 20% lower), and seven patients had stable creatinine values. Eight patients ultimately required long-term dialysis. In the remaining 21 patients, with an average follow-up of 32 months, the average creatinine concentration was 220 mumol/L (2.51 mg/dL), still a significant improvement. Thus, we have demonstrated the relative safety and benefit of operating on these high-risk patients.

Arteriosclerosis↗

PubMed1987

The treatment of complicated appendicitis in children. What is the gold standard?

From 1976 to 1985, 233 consecutive children were treated for appendicitis by a standardized protocol. Forty-nine percent of these cases were complicated: 11% by gangrene, 33% by perforation, and 4% by perforations with well-developed abscesses. Treatment of gangrenous and perforated appendicitis consisted of administration of ampicillin sodium, gentamicin sulfate, and clindamycin phosphate; appendectomy; and saline peritoneal irrigation. Transperitoneal drainage was not used. Skin and subcutaneous tissues were left open for delayed primary wound closure. Perforations with well-developed abscesses were treated with triple antibiotic therapy and interval appendectomy. The only infectious complication was one intra-abdominal abscess. There were no wound infections or deaths. The rate of infectious complications was 0.9%, and the overall morbidity was 4.4%. This standardized treatment of complicated appendicitis in children prevents wound infection and significantly decreases the incidence of intra-abdominal abscess formation and mortality.

Abscess↗

PubMedDate not supplied

Ultrasound-guided thrombin injection is a safe and durable treatment for femoral pseudoaneurysms.

Ultrasound-guided percutaneous thrombin injection has recently been described as a treatment for postcatheterization femoral pseudoaneurysms. Although ultrasound guided compression offers another nonoperative treatment option, thrombin injection has shown superior initial success rates. Reports of follow-up for thrombin injection longer than 30 days are currently lacking. The authors reviewed their initial experience with thrombin injection and prospectively evaluated patients for occult late recurrences of pseudoaneurysm and for distal circulatory complications. Records and vascular laboratory data for all patients treated with ultrasound-guided thrombin injection were reviewed for an 18-month period. Tibial vessel Doppler waveforms and ankle/brachial indices were routinely obtained before and after thrombin injection. Follow-up duplex examinations were performed within 24 hours of initial treatment. In the prospective portion of the study, successfully treated patients underwent a repeat femoral duplex scan and lower extremity arterial examination for comparison with the pretreatment studies. Forty-nine of 52 femoral pseudoaneurysms (94%) were successfully treated with ultrasound guided thrombin injection. One immediate failure and 2 early recurrences were treated surgically. There was 1 thrombotic complication of the native circulation identified at the time of injection. Follow-up studies were obtained in 32 of 46 available patients with a mean length of follow-up of 9 months (range 3-17 months). No late recurrences of the pseudoaneurysms or arterial-venous fistulas were observed. No distal circulatory complications were detected by arterial waveform analysis. Three deaths occurred in the interim (cardiac related). Two patients were lost to follow-up. The remaining 12 patients reported no additional limb complications but declined to be restudied. Ultrasound-guided thrombin injection is a safe, effective, and durable treatment for iatrogenic pseudoaneurysms. Thrombin injection should be the therapy of choice for catheter-related femoral false aneurysms.

Adult↗

PubMedDate not supplied

Functional changes in canine saphenous veins after cryopreservation.

This study was designed to determine the functional characteristics of the endothelium, smooth muscle and nerve terminals of cryopreserved veins. Freshly harvested and cryopreserved canine saphenous veins were cut into rings. In some rings, the endothelium was removed. Cryopreserved veins were stored at -196 degrees C for at least 3 weeks prior to use. All rings contracted in a concentration-dependent manner to depolarization with KCl and to alpha-adrenergic stimulation; the maximal tensions were significantly less in cryopreserved than in freshly harvested veins. Calcium ionophore A23187 caused greater relaxations in rings with than without endothelium in freshly harvested and cryopreserved veins. These relaxations were reduced significantly by methylene blue and NG-monomethyl-L-arginine (L-NMMA) only in fresh veins. Cocaine-sensitive uptake of H3-norepinephrine was reduced following cryopreservation. Immediately after cryopreservation, the production of prostacyclin was elevated. The calcium ionophore A23187 stimulated production of prostacyclin only in freshly harvested veins. Tissue content of endothelin did not change following cryopreservation. These results suggest that cryopreservation of canine saphenous veins alters nerve terminals and decreases the ability of the smooth muscle to contract. The endothelium releases an endothelium-derived relaxing factor and prostanoids following cryopreservation but the ability to synthesize nitric oxide is probably reduced. These changes following cryopreservation may affect patency of the veins when used as arterial grafts.

Animals↗