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Biomedical subjects

R B Smith

Publications and source records attributed to R B Smith.

At least 91 records · Page 5Linked to original sources
PubMed1994

A prospective evaluation of surgically treated groin complications following percutaneous cardiac procedures.

During an 18-month study period, 100 noncardiac surgical complications of a percutaneous cardiac interventional procedure were treated at Emory University Hospital. These were predominantly pseudoaneurysms (61.2%), groin hematomas (11.2%) arteriovenous fistulae (10.2%), and external bleeding (6.1%). Less common complications included retroperitoneal hematomas (5.1%), arterial thromboses (3.1%), groin abscess (2.0%), and a mycotic pseudoaneurysm (1.0%). The complication rate following diagnostic catheterization was 0.6 per cent, after percutaneous transluminal angioplasty, 1.5 per cent, atherectomy 2.2 per cent, and after stent placement 16 per cent (P < 0.0001). The arterial puncture site was other than the common femoral artery in 34 per cent of cases. Risk factors for the development of complications were postprocedure anticoagulation (P < 0.0001), female gender (P < 0.005), increased age (P < 0.0001), and small stature (P < 0.0001). Duplex scanning had 98 per cent accuracy in diagnosis of suspected groin complications, and clinical diagnostic accuracy was 77 per cent. We describe our technique for repair of pseudoaneurysms and arteriovenous fistula and discuss the possible future role of ultrasound guided compression. Mean hospital stay after the procedure was 3.2 days. Morbidity of surgical repair was 21 per cent and mortality was 2.1 per cent. Groin complications following percutaneous cardiac procedures are related to the type of procedure performed, female gender, and periprocedure anticoagulation.

Abscess↗
PubMed1993

Acute lower extremity ischemia after cardiac surgery.

A retrospective review during a 5-year period (1987 to 1992) was conducted of all patients manifesting leg ischemia after major cardiac surgery. There were 7,620 procedures performed, and 65 (0.85%) patients (mean age: 65 years) were identified with acute ischemia. Diagnosis was made by physical examination, during which a cool pulseless extremity without pedal Doppler signals was noted in 63 of 65 patients (97%). An intra-aortic balloon pump (IABP) was inserted in 56 patients (86%). Treatment regimens included medical management (17), IABP removal (4), IABP removal and thromboembolectomy (24), thromboembolectomy and endarterectomy with patch angioplasty (10), femoral-femoral bypass (17), other bypasses (6), fasciotomy (10), and amputation (16). Morbidity was 92% and mortality was 46%. Mortality was 11% in those patients developing ischemia without an IABP. Acute leg ischemia after cardiac surgery is predictive of high morbidity and mortality. This reflects the compromised cardiac status and multi-system disease. Treatment alternatives are based on the overall clinical status, degree of arterial insufficiency, and distribution of pre-existing peripheral vascular disease. However, ultimate limb salvage had no influence on overall patient survival in our study.

Acute Disease↗
PubMed1993

Extrathoracic bypass procedures for proximal common carotid artery lesions.

During a 10-year period ending in December 1991, 31 extrathoracic bypass procedures were performed in 29 patients for proximal common carotid artery atherosclerotic stenosis or occlusion. This included 16 men and 13 women, with a mean age of 63 years. Indications for surgery included transient ischemic attacks in 23 patients (79%), nonfocal symptoms in 4 patients (14%), and asymptomatic proximal common carotid artery stenosis associated with near-total occlusion of the internal carotid artery in 2 patients (7%). Severe proximal stenosis or complete occlusion of the common carotid artery was demonstrated angiographically in all cases. Subclavian-to-carotid bypass was performed in 26 cases and carotid-to-carotid bypass in 5 cases. Seventy-four percent of the bypass procedures were to the common carotid artery and 26% to the external carotid artery. Endarterectomy of the common carotid bifurcation was performed in conjunction with the bypass procedure in 13 cases and vertebral artery transposition in 2 other cases. Saphenous vein was used as the bypass conduit in 65% and prosthetic grafts in 35% of cases. There were no perioperative strokes or deaths in this series, and the mean postoperative hospital stay was 5 days. Follow-up ranged from 2 to 118 months (mean: 38.4 months). Graft occlusion occurred in two cases during the follow-up period (3-year patency rate: 90%), with recurrence of symptoms in one patient, which necessitated revision. Three patients had persistence or recurrence of symptoms despite patency of the graft, one other patient sustained a posterior circulation infarct, and there was one death unrelated to carotid vascular disease during the follow-up period. This experience shows that extrathoracic bypass procedures are safe and well tolerated for symptomatic proximal common carotid artery stenosis or occlusion. This method of reconstruction has excellent long-term patency and protection against further anterior circulation neurologic events.

Anastomosis, Surgical↗
PubMed1993

The contemporary incidence of lymph node metastases in prostate cancer: implications for laparoscopic lymph node dissection.

The incidence of lymphatic metastases in 229 consecutive patients with clinically localized prostatic cancer was assessed. Only 13 patients had nodal metastases, for an incidence of 5.7%. A monoclonal prostatic specific antigen value of more than 40 ng./ml. correlated with a positive predictive value of 53% for nodal metastases. Routine laparoscopic node dissection is unnecessary considering the low incidence of nodal metastases.

Humans↗
PubMed1993

Canine tracheal blood flow after endotracheal tube cuff inflation during normotension and hypotension.

Tracheal tissue damage associated with endotracheal intubation may be a direct result of high mucosal contact pressure (MCP) generated by the endotracheal tube cuff. Tracheal blood flow (TBF) was measured at MCPs in the normotensive and hypotensive (mean arterial blood pressure, 50 mm Hg) canine model. Control TBFs through the individual rings in contact with the endotracheal tube cuff ranged between 26.6 +/- 2.7 and 44.5 +/- 5.0 with a mean of 35.0 +/- 2.5 mL.min-1 x 100 g-1 during normotension, and 15.0 +/- 4.9 and 22.5 +/- 5.0 with a mean of 18.9 +/- 0.9 mL.min-1 x 100 g-1 during hypotension. TBF was reduced significantly at all elevated MCPs in both groups. TBF also was measured during normotension and hypotension after cuff inflation to 15 mm Hg MCP at 1-h intervals for 3 h. TBF was reduced significantly from control to 14.9 +/- 1.5 mL.min-1 x 100 g-1 after 1 h during normotension, and continued to decline to 6.1 +/- 0.9 mL.min-1 x 100 g-1 after 3 h. During hypotension, TBF decreased significantly from control to 6.1 +/- 0.6 mL.min-1 x 100 g-1 at 1 h and remained unchanged at 3 h. These findings suggest that even at 20 mm Hg MCP, significant reductions in TBF may occur. For prolonged endotracheal intubation, especially during hypotension, significant reductions in TBF may occur at even lower MCP.

Animals↗
PubMed1993

Design and pharmacodynamic evaluation of novel dual release formulations of triazolam.

Triazolam is an effective hypnotic that can cause amnesia and psychomotor performance decrements, particularly after a 0.5 mg dose. Previous pharmacodynamic studies suggested a relationship between these effects and triazolam plasma concentration. A novel dual release bilayer tablet was designed to mimic the onset of action of a 0.25 mg dose and to maintain the duration of a 0.5 mg dose without the side effects associated with the 0.5 mg dose. The immediate release component of the bilayer tablet contained 0.25 mg triazolam while the sustained release component contained 0.15 mg triazolam. Two prototype formulations of the bilayer tablet, differing in rate of release in the sustained release component, were tested against a conventional 0.5 mg triazolam compressed tablet and placebo in a single-dose, double-blind, four-way crossover study in healthy male subjects. Triazolam plasma concentration time profile was obtained over 12 hours following single administration of each treatment. Effects of triazolam on central nervous system function were evaluated using psychomotor performance tests, immediate and delayed recall tests and rating of sedation. The triazolam plasma concentrations were not significantly different among the active drug treatments, although the dual release tablets did give the expected profiles. There were significant differences in triazolam effects on memory and psychomotor performance. The slowest releasing dual-release tablet showed significantly less psychomotor impairment and memory deficit than the conventional tablet. There was no difference in sedation among the active drug treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Selective screening for coronary artery disease in patients undergoing elective repair of abdominal aortic aneurysms.

PURPOSE: The purpose of this study was to retrospectively evaluate the effectiveness of screening for coronary artery disease before elective repair of abdominal aortic aneurysms (AAA) was performed. METHODS: Results of a screening algorithm for coronary artery disease in 263 patients admitted to a single hospital for elective repair of AAA between January 1986 and December 1989 were analyzed. Patients with no coronary artery disease indicators proceeded to surgery without further workup. Patients with cardiac disease indicators underwent dipyridamole-thallium scintigraphy, and patients with angina were screened by use of cardiac catheterization; those with a recent coronary revascularization underwent no additional screening unless symptoms or electrocardiographic changes suggested an intervening event. Twenty-eight patients underwent no screen other than medical history and electrocardiogram. RESULTS: Among 164 patients screened with dipyridamole-thallium scintigraphy, 44 patients had redistribution defects that required catheterization, and 11 of these underwent coronary revascularization. Cardiac catheterization was performed directly in 42 patients, which led to 11 revascularizations before AAA repair. Previous coronary artery bypass or percutaneous transluminal angioplasty obviated additional screening in 29 patients. Of the 263 scheduled AAA repairs, 15 were cancelled because of unacceptable operative risks, 13 for cardiac reasons. One patient died of a ruptured AAA after an uneventful coronary artery bypass. Among the 247 AAA repairs performed, there were three perioperative deaths (1.2%), all of which resulted from sudden cardiac events; three additional patients had nonfatal myocardial infarctions (1.2%), for a total cardiac complication rate of 2.4%. CONCLUSIONS: The low rate of cardiac complications in this experience affirms the effectiveness of preoperative screening and selective coronary revascularization before AAA repair.

Aged↗
PubMed1993

Paraanastomotic aneurysms of the abdominal aorta.

PURPOSE: Aneurysm formation after abdominal aortic bypass reconstruction is an infrequent but underestimated complication. Aneurysms may occur after aortic prosthetic reconstruction for both occlusive and aneurysmal disease, may occur early or late, and may be classified as a pseudoaneurysm or true aneurysm. METHODS: Thirty-one cases in 29 patients treated at a tertiary referral center from 1980 to 1992 were retrospectively reviewed. Iliac and femoral aneurysms were excluded. The indication for initial abdominal aortic grafting had been aneurysmal disease in 19 patient and occlusive disease in 10 patients. RESULTS: There were 25 pseudoaneurysms and six true aneurysms, the latter followed grafting for aneurysmal disease. The current aneurysm (mean size 7.1 cm) was at the proximal aortic anastomosis in 27 cases and at the distal aortic anastomosis in two cases. Symptoms at presentation included abdominal pain (14), mass (12), claudication (9), back pain (6), and gastrointestinal bleeding (3). Surgical management included interposition tube grafting (16), aortoiliofemoral bypass (9), and graft removal with extraanatomic bypass (3). The overall operative morbidity rate was 73%, and mortality rate was 21%. CONCLUSIONS: Paraanastomotic aortic aneurysms are being increasingly recognized and are associated with high morbidity and mortality rates. Patients should be periodically studied after aortic grafting with abdominal ultrasonography for early detection of this potentially serious complication. Elective surgical repair is advocated in the effort to minimize morbidity rates.

Aged↗