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Biomedical subjects

M M Wynn

Publications and source records attributed to M M Wynn.

8 recordsLinked to original sources
PubMed2000

Clamp and sew techniques in thoracoabdominal aortic surgery using naloxone and CSF drainage.

Surgical repair of thoracoabdominal (TAA) and thoracic aneurysm is challenging, with the potentials for high morbidity and mortality. There is no standardized operative approach. Operative management of TAA consists of simple clamp-and-sew techniques with adjuncts, cerebrospinal fluid (CSF) drainage, naloxone administration, and intraoperative hypothermia, to protect the spinal cord. The use of CSF drainage and naloxone administration has reduced paraplegia to 3.4%, compared with 21% when none of these adjunctive spinal cord measures were used. The authors discuss their operative strategy, surgical technique, and results at the University of Wisconsin Hospital and Clinics.

Aorta, Abdominal↗
PubMed1999

Thoracoabdominal aortic aneurysm. How we do it.

A systematic approach to paraplegia risk in the surgical treatment of thoracoabdominal aortic aneurysms based on effective strategies identified from the experimental literature is discussed. With this approach, collateral blood flow, rather than direct intercostal reimplantation, moderate hypothermia and endorphin receptor, is emphasized blockade. The result has been a 10-fold reduction in paraplegia risk in elective patients and a 5-fold reduction in acute patients. This reduction in paralysis risk has resulted in improved short- and long-term survival.

Aortic Aneurysm, Abdominal↗
PubMed1998

Cardiac function is a risk factor for paralysis in thoracoabdominal aortic replacement.

PURPOSE: We studied factors that influence paralysis risk, renal function, and mortality in thoracoabdominal aortic replacement. METHODS: We prospectively collected preoperative demographic and intraoperative physiologic data and used univariate and multivariate analyses to correlate this data with risk factors for paralysis. A mathematical model of paraplegia risk was used to study the efficacy of paraplegia reduction strategies. We analyzed preoperative and operative factors for paralysis risk, renal function, and mortality for 217 consecutive patients surgically treated from 1984 through 1996 for 176 thoracoabdominal and 41 thoracic aneurysms at the University of Wisconsin Hospital and Clinics. No patient had intercostal reimplantation or assisted circulation. One hundred fifty patients (group A) received cerebrospinal fluid drainage (CSFD) and low-dose naloxone (1 microg/kg/hour) as adjuncts to reduce the risk of paralysis. Sixty-seven patients (group B) did not receive CSFD and naloxone. RESULTS: Seventeen deficits occurred in 205 surviving patients: 5 of the 147 in group A (expected deficits = 31) and 12 of the 58 in group B (expected deficits = 13) (p < 0.001). In a multivariate logistic regression model, acute presentation, Crawford type 2 aneurysm, group B membership, and a decrease in cardiac index with aortic occlusion remained significant risk factors for deficit (p < 0.0001). By odds ratio analysis, group A patients had 1/40th the risk of paralysis of group B. The only significant predictor of postoperative renal function was the preoperative creatinine level (p < 0.0001); renal revascularization significantly improved renal function. The mortality rate was 1.6% (2) for patients undergoing elective treatment and 21% (19) for patients who had acute presentations. Acute presentation, age, and the preoperative creatinine level were found to be significant factors for operative mortality in a logistic regression model (p < 0.001) and defined a group at high risk for death. CONCLUSIONS: CSFD and low-dose naloxone significantly reduce the paralysis risk associated with thoracoabdominal aortic replacement. A decrease in the cardiac index with aortic occlusion is a previously unreported variable that defines a subset of patients at higher risk for paralysis.

Adolescent↗
PubMed1994

Combined use of cerebral spinal fluid drainage and naloxone reduces the risk of paraplegia in thoracoabdominal aneurysm repair.

PURPOSE: This report summarizes our experience with the use of cerebral spinal fluid drainage (CSFD) and naloxone for prevention of postoperative neurologic deficit (paraplegia or paraparesis). METHODS: We reviewed 110 consecutive patients with 86 thoracoabdominal aneurysms and 24 thoracic aneurysms. The status of 47 patients (43%) was acute (rupture or dissection), and the status of 52 (47%) was Crawford type I or II. None of the patients had intercostal artery reimplantation. There were two patient groups for analysis of neurologic deficit risk. Group A (61 patients) received naloxone and CSFD, and group B (49 patients) did not. RESULTS: One deficit occurred in group A and 11 deficits occurred in group B (p = 0.001). By multiple logistic regression analysis, the variables acute status, Crawford type II, or group B classification were significant factors for deficit risk. Use of the same logistic regression analysis on the subgroup of 47 patients with acute aneurysms and 33 patients with Crawford type 2 aneurysms confirmed the protective effect of combined CSFD and naloxone (group A) and that clinical presentation and extent of aorta replaced are the primary risk factors for development of deficit. To test this conclusion we developed a highly predictive model (correlation coefficient 0.997 with 16 series of thoracoabdominal aneurysms) for neurologic deficit. We applied our data to this model. Group B had the predicted number of deficits, and group A had substantially fewer deficits than predicted. CONCLUSIONS: We conclude that the combined use of CSFD and naloxone offers significant protection from neurologic deficits in patients undergoing thoracoabdominal and thoracic aortic replacement.

Adolescent↗
PubMed1990

Naloxone and spinal fluid drainage as adjuncts in the surgical treatment of thoracoabdominal and thoracic aneurysms.

Forty-seven patients who were treated for thoracoabdominal or thoracic aneurysms over a 5 1/2-year period were analyzed for neurologic deficit risk. Patients were divided into two groups for analysis. Twenty-four patients, who were treated from January 1984 to December 1986, did not undergo spinal fluid drainage or naloxone administration (group A). Twenty-three patients, who were treated from January 1987 to August 1989, had spinal fluid drainage (group B); 12 patients in this group also received naloxone as an intravenous drip at 1 microgram/kg/hr for 48 hours after surgery. Permanent neurologic deficits occurred in seven (29%) group A patients but in only one (4%) group B patient, who did not receive naloxone (p less than 0.03). The first two group B patients to receive naloxone showed complete reversal of neurologic deficits on waking from anesthesia. This significant reduction in neurologic deficit was associated with an increased 1-year survival rate (72% in group A, 91% in group B). We conclude that the use of naloxone and spinal fluid drainage reduces the incidence of neurologic deficit that is associated with repair of thoracoabdominal and thoracic aortic aneurysms. This reduction in neurologic deficit is associated with improved survival in the long term. The observed reversal of postoperative neurologic deficits with naloxone implicates opiates as a major factor in the pathophysiology of spinal cord ischemia.

Adult↗
PubMed1984

Role of coronary artery bypass surgery after intracoronary streptokinase infusion for myocardial infarction.

Intracoronary streptokinase infusion has been shown to improve left ventricular function and reduce hospital mortality in patients with acute myocardial infarction. Adjuvant coronary artery bypass surgery is of value in many of these patients who have recurrent angina, circulatory instability, severe coronary artery occlusive disease, or a high risk of reinfarction. There is little, if any, evidence that immediate coronary artery bypass surgery affects the results adversely--either because of recent myocardial infarction or recent streptokinase infusion, and early operation appears to be a safe and worthwhile modality of treatment in this group of patients with myocardial infarction.

Coronary Artery Bypass↗