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Biomedical subjects

P B Harrison

Publications and source records attributed to P B Harrison.

At least 19 recordsLinked to original sources
PubMed1998

A comparison of sonographic examinations for trauma performed by surgeons and radiologists.

BACKGROUND: It has been demonstrated that surgeons and surgery residents, trained in the focused abdominal sonographic examination, are able to accurately and reliably evaluate trauma patients. Despite this, radiologists have objected to surgeon-performed sonography for several reasons. We set out to compare the accuracy of sonographic examinations performed by surgery residents and radiologists. METHODS: A retrospective review of medical records of all trauma patients who received focused ultrasound examinations from January 1, 1995, through June 30, 1996, at one of two American College of Surgeons-verified Level I trauma centers in the same city was undertaken. Ultrasound examinations were performed by surgery residents at trauma center A (TCA) and by radiologists or radiology residents at trauma center B (TCB). Findings for each patient were compared with the results of computed tomography, diagnostic peritoneal lavage, operative exploration, or observation. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated for each group of patients. Comparison of patient charges for the trauma ultrasound examinations at each of the trauma centers was also made. RESULTS: Patient populations at the two centers were similar except that the mean Injury Severity Score at TCB was higher than at TCA (11.74 vs. 9.6). Sensitivity, specificity, accuracy, or negative predictive value were not significantly different between the two cohorts. A significantly lower positive predictive value for examinations performed by surgery residents was noted and attributed to a lower threshold of the surgery residents to confirm their findings by computed tomography. Billing data revealed that the average charge for trauma sonography by radiologists (TCB) was $406.30. At TCA, trauma sonography did not generate a specific charge; however, a $20.00 sum was added to the trauma activation fee to cover ultrasound machine maintenance and supplies. CONCLUSION: Focused ultrasound examination in the trauma suite can be as safely and accurately performed by surgery residents as by radiologists and radiology residents and should be a routine part of the initial trauma evaluation process.

Adolescent↗
PubMed1996

Big cat attack: a case study.

A 28-year-old man was attacked by a large female tiger at an exotic animal farm, sustaining penetrating injuries to the neck and pharynx as well as a cervical spine fracture. This case and review of the literature demonstrates the ability of these animals to cause significant trauma and occult injuries. Furthermore, this case demonstrates the need for a high index of suspicion when treating these patients, as serious underlying bony and soft tissue damage can easily be overlooked.

Adult↗
PubMed1995

PASG: does it help in the management of traumatic shock?

A prospective, randomized study was designed to determine the efficacy of pneumatic antishock garment (PASG) in the treatment of traumatic shock in a medium-size urban community. A total of 291 traumatic shock patients were assigned to either the PASG or No-PASG treatment groups. Of these, data from 248 patients were analyzed in detail. Analysis of demographic factors--such as age, sex, and mechanism of injury--as well as prehospital evaluative tools--such as trauma and CRAMS scores, and injury severity scores--revealed that the two groups were well-matched. This study did not demonstrate significant differences in hospital stay or mortality between PASG and No-PASG patients. Similarly, in the subset of patients with blunt trauma, PASG was not found to be beneficial.

Adult↗
PubMed1995

Duplex ultrasonography criteria for internal carotid stenosis of more than 70% diameter: angiographic correlation and receiver operating characteristic curve analysis.

OBJECTIVE: To determine duplex ultrasonography criteria for detecting stenosis of 70% or more in the internal carotid artery, to be used as a means of selecting candidates suitable for endarterectomy (a procedure suggested by the North American Symptomatic Carotid Endarterectomy Trial as appropriate for symptomatic patients with 70% to 99% stenosis). PATIENTS AND METHODS: Between Jan. 1, 1991, and Apr. 30, 1993, 120 patients underwent internal carotid angiography at a tertiary care hospital for transient ischemic attacks, asymptomatic bruits or preoperative assessment. Of these, 83 also underwent duplex ultrasonography within 31 days of angiography. The angiographic and sonographic studies for 145 vessels in 75 of the patients (50 men and 25 women) were suitable for further study. The sonographic criteria were selected on the basis of a receiver operating characteristic curve relating peak systolic velocity of the internal carotid artery to the degree of stenosis determined angiographically. RESULTS: Angiography indicated that 33 of the vessels had stenosis of 70% or more and that 12 additional vessels were completely occluded. The combined sonographic criteria of peak systolic velocity of less than 40 cm/s or 175 cm/s or more yielded 91% sensitivity and 60% specificity for angiographically determined stenosis of 70% or more. CONCLUSION: In this patient population the combined criteria of peak systolic velocity of less than 40 cm/s or 175 cm/s or more were highly sensitive and reasonably specific for internal carotid artery stenosis of 70% or more.

Angiography↗
PubMed1993

The contribution of needle size and other factors to headache following myelography.

The author performed a randomized prospective study of the effects of needle size and of age, sex, myelogram type and operators on the incidence of headache following myelography. In 113 patients randomized to 22 G and 25 G needle groups, data were obtained by questionnaire on the frequency of headache up to five days following the procedure. The influence of needle size was statistically insignificant (63%, 48%, p > 0.05). Age (p = 0.0002), sex (p = 0.01), myelogram type (p = 0.002) and myelographer (p = 0.03) significantly affected the frequency of headache. The size of the dural perforation appears to be less important than factors relating to age, sex, myelogram type and individual myelographers in the development of headache after myelography.

Adult↗
PubMed1993

The questionable utility of mandatory screening for the human immunodeficiency virus.

Trauma patients have been identified as a high-risk group for human immunodeficiency virus (HIV) infection, particularly those patients with penetrating injuries from urban violence. We prospectively evaluated more than 2,000 trauma patients for HIV infection at our ACS-certified trauma center and report the results. Between September 1987 and December 1991, 2,004 patients were admitted to our trauma unit. All patients underwent HIV antibody assay by protocol. Three patients had positive test results, and all were confirmed as true positives. Two patients were known at the time of their trauma to be HIV positive, and the third had engaged in high-risk behavior. No health care worker reported inoculation with or mucosal exposure to HIV from any of these patients. In our trauma unit, the prevalence of HIV infection was only 0.15%. More than $74,000 was spent on screening without demonstrable benefit to the patients or increased protection for the trauma team. Routine testing of patients for HIV can be justified to establish epidemiologic parameters and in the case of high-risk groups, but it is not cost-effective in low-risk groups. Persistent testing of populations at low risk is a futile expenditure of precious health care dollars and is of questionable utility.

AIDS Serodiagnosis↗
PubMed1993

Thrombolysis for occluded vein bypass grafts through surgical access.

PURPOSE: This report describes surgical access to occluded vein grafts for thrombolysis by direct cutdown where indirect angiographic techniques have failed. METHOD: A sheath is introduced directly into the proximal vein graft. Distal thrombus is lysed following standard protocol. The residual thrombus at the origin of the graft is removed surgically, and the area is closed with a patch angioplasty. RESULTS: Distal thrombus was completely lysed in two vein grafts without bleeding complications. CONCLUSION: The thrombus "cork" that forms at the upper end of an occluded vein graft may deflect the angiographer's guide wire, but the distal thrombus usually remains soft and amenable to lysis. Angiographic access should not be a limiting factor in thrombolysis of an occluded vein graft.

Graft Occlusion, Vascular↗
PubMed1992

Systemic blood flow to the lung after bronchial artery occlusion in anesthetized sheep.

To compare the effectiveness of different embolizing agents in reducing or redistributing bronchial arterial blood flow, we measured systemic blood flow to the right lung and trachea in anesthetized sheep by use of the radioactive microsphere method before and 1 h after occlusion of the bronchoesophageal artery (BEA) as follows: injection of 4 ml ethanol (ETOH) into BEA (group 1, n = 5), injection of approximately 0.5 g polyvinyl alcohol particles (PVA) into BEA (group 2, n = 5), or ligation of BEA (group 3, n = 5). After occlusion, angiography showed complete obstruction of the bronchial vessels. There were no changes in tracheal blood flow in any of the groups. Injection of ETOH produced a 75 +/- 14% (SD) reduction in flow to the middle lobe (P less than 0.02) and a 75 +/- 13% reduction to the caudal lobe (P less than 0.01), whereas injection of PVA produced a smaller reduction in flow to these two lobes (41 +/- 66 and 51 +/- 54%, respectively). After BEA ligation there was a 52 +/- 29% reduction in flow to the middle lobe and a 53 +/- 38% reduction to the caudal lobe (P less than 0.05). This study has significant implications both clinically and experimentally; it illustrates the importance of airway collateral circulation, in that apparently complete radiological obstruction of the BEA does not necessarily mean complete obstruction of systemic blood flow. We also conclude that, in experimental studies in which the role of the bronchial circulation in airway pathophysiology is examined, ETOH is the agent of choice.

Animals↗
PubMed1992

Laparoscopic cholecystectomy during pregnancy in symptomatic patients.

BACKGROUND: The management of symptomatic biliary tract disease during pregnancy is controversial. Although most patients receive temporizing medical therapy, some authors have advocated a more aggressive surgical approach. We have extended this surgical approach to include laparoscopic cholecystectomy. METHODS: Five women with pregnancies at 13 to 23 weeks' estimated gestational age underwent laparoscopic cholecystectomy for symptomatic cholelithiasis or acute cholecystitis between March and September 1991. RESULTS: No complications occurred, and the postoperative courses of all patients were unremarkable. Four patients have been delivered of healthy babies, and the fifth patient is still pregnant at the time of this report. CONCLUSIONS: Laparoscopic cholecystectomy appears to be a safe treatment for selected patients with symptomatic biliary tract disease during pregnancy. Further study is warranted to determine its proper role in managing this difficult clinical problem.

Acute Disease↗
PubMed1992

Atherectomy. Early use of three different methods.

The authors report their initial experience in 52 patients with three different techniques of peripheral artery atherectomy--the Tracwright (Kensey), used in 19 patients, the Simpson AtheroCath, used in 19 patients and the transluminal extraction catheter, used in 14 patients. The indications for atherectomy were claudication in 42 (80%) and limb-threatening ischemia in 10 (19%). There were no deaths. Complications included three arterial perforations, one thrombosis and one groin hematoma requiring operative evacuation. There were no distal embolizations. Atherectomy was initially unsuccessful in 15 (29%) patients. For the successfully completed procedures, the 1-year primary patency rates were as follows: Tracwright (Kensey) catheter 56%, Simpson catheter (63%) and transluminal extraction catheter (0%). Use of subsequent nonoperative procedures on recurrent stenoses produced secondary patency rates of 77% for the Tracwright (Kensey) technique, 80% for the Simpson catheter technique and 78% for the transluminal extraction catheter technique. The authors conclude that their early results justify further evaluation of these three techniques. Use of the transluminal extraction catheter is associated with higher rates of occlusion and restenosis.

Aged↗
PubMed1991

Hyperperfusion syndrome after carotid endarterectomy. CT changes.

This article describes the CT scans of two patients who, following carotid endarterectomy, developed headache and seizures suggestive of hyperperfusion syndrome. Their CT scans demonstrated ipsilateral mass effect and white matter hypodensity. One patient progressed to hemorrhage and died. Although infarction is described as the commonest neurologic event to occur after carotid endarterectomy, autopsy or cerebral blood flow studies in these patients suggests that the changes were due to hyperperfusion rather that infarction.

Aged↗
PubMed1991

Total occlusion of the common carotid artery with patent internal carotid artery. Identification with color flow Doppler imaging.

With common carotid artery occlusion there is usually no flow in the distal vessels. However, flow to the ipsilateral internal common carotid artery may be maintained by collateral vessels. Nine of 1100 patients referred for carotid duplex sonography were found to have occluded common carotid arteries. Five of these patients had collateral circulation with reconstitution of flow via the external carotid artery. The color Doppler sonograms of three representative patients are presented. There was antegrade flow in the internal carotid artery with retrograde flow in the external carotid artery.

Adult↗
PubMed1990

Embolization of a catheter-related hepatic artery pseudoaneurysm after long-term biliary drainage.

Hemobilia is a frequent complication of percutaneous transhepatic biliary drainage, occurring most commonly at the time of initial catheter placement. The authors report on the angiographic diagnosis and embolization of a pseudoaneurysm of the right hepatic artery in a patient with hemobilia. This occurred after 2.5 years of catheter drainage for biliary obstruction due to malignant disease. Bleeding as a complication of biliary drainage can be the result of inadvertent placement of catheter side holes in the hepatic parenchyma, iatrogenic arterioportal and arteriohepatic venous shunts and pseudoaneurysms. This case report illustrates that hemobilia, even with long-term percutaneous transhepatic biliary drainage, may be associated with a radiologically treatable, drainage-related vascular abnormality rather than simply diffuse hemorrhage from a friable tumor.

Adult↗
PubMed1990

Focal brain lesions on computed tomography in patients with acquired immune deficiency syndrome.

Neurologic involvement is common in patients with acquired immune deficiency syndrome (AIDS). To assess the computed tomographic findings in AIDS, the authors reviewed 12 consecutive patients found to have focal brain lesions representing AIDS complications on computed tomography and having histologic or clinical proof of the diagnosis. Five patients had toxoplasmosis, six had lymphoma and one had both conditions sequentially. The finding of multiple lesions and mass effects with edema was more common with toxoplasmosis. In six patients who had toxoplasmosis 33 nodules were observed compared with only 8 in seven patients who had lymphoma. Disease extending linearly along the ventricular wall was typically seen in patients who had lymphoma.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Color flow duplex screening of infrainguinal grafts combining low- and high-velocity criteria.

The aim of this prospective study was to evaluate the ability of duplex ultrasonography to identify infrainguinal grafts at high risk for failure. The criteria used identified low flow by low peak systolic velocity (less than 45 cm/s) and stenosis by high velocity (greater than 300 cm/s) or by velocity at the stenosis three times the velocity in the adjacent normal graft. A total of 114 patent grafts were scanned and compared with concurrent angiograms. Duplex scanning correctly identified 18 high-risk grafts by low-flow criteria and an additional 21 by stenosis criteria. There was one false-negative finding (sensitivity 98 percent). The velocity ratio of the stenosis to the adjacent graft was useful in estimating the degree of stenosis. Color flow duplex imaging reduced examination time through visual feedback by highlighting the graft and areas of high velocity. These results indicate that color flow duplex scanning, combining low- and high-peak systolic criteria, is a very sensitive screening test in the early detection of failing grafts.

Blood Vessel Prosthesis↗
PubMed1988

Iliac artery aneurysms arising in patients having had resections of abdominal aneurysms.

We report the angiographic, computed tomographic, and ultrasonographic findings in two patients with iliac artery aneurysms detected several years after undergoing vascular graft surgery to the aorta. These lesions are often silent until serious complications occur, and they should be treated even when asymptomatic. Radiologists should be familiar with this complication so that it may be more readily diagnosed.

Aged↗