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Biomedical subjects

T D Martin

Publications and source records attributed to T D Martin.

At least 37 records · Page 2Linked to original sources
PubMed1996

The effect of temperature management during cardiopulmonary bypass on neurologic and neuropsychologic outcomes in patients undergoing coronary revascularization.

Several studies suggest that normothermic ("warm") bypass techniques may improve myocardial outcomes for patients undergoing cardiac operations. Normothermic temperatures during cardiopulmonary bypass may, however, decrease the brain's tolerance to the ischemic insults that accompany all cardiac procedures. To assess the effect of bypass temperature management strategy on central nervous system outcomes in patients undergoing coronary revascularization, 138 patients were randomly assigned to two treatment groups: (1) hypothermia (n = 70), patients cooled to a temperature less than 28 degrees C during cardiopulmonary bypass, or (2) normothermia (n = 68), patients actively warmed to a temperature of at least 35 degrees C. Patients underwent detailed neurologic examination before the operation, on postoperative days 1 to 3 and 7 to 10, and at approximately 1 month after operation. In addition, a battery of five neuropsychologic tests was administered before operation, on postoperative days 7 to 10, and at the 4- to 6-week follow-up visit. Patients in the normothermic treatment group were older (65 +/- 10 vs 61 +/- 11 years in the hypothermic group), had statistically less likelihood of preexisting cerebrovascular disease, and had higher bypass blood glucose values (276 +/- 100 mg/% vs. 152 +/- 66 mg/% in the hypothermic group). All other patient characteristics and intraoperative variables were similar in the two treatment groups. Seven of 68 patients in the normothermic group were found to have a central neurologic deficit, compared with none of the patients cooled to 28 degrees C (p = 0.006). Performance on at least one neuropsychologic test deteriorated in the immediate postoperative period in more than one half of all patients in both treatment groups but returned to preoperative levels approximately 1 month after the operation in most (85%). This pattern was not related to bypass temperature management strategy. We conclude that active warming during cardiopulmonary bypass to maintain systemic temperatures > or = 35 degrees C increases the risk of perioperative neurologic deficit in patients undergoing elective coronary revascularization.

Age Factors↗
PubMed1996

Visceral ischemia and organ dysfunction after thoracoabdominal aortic aneurysm repair. A clinical and cost analysis.

OBJECTIVE: Repair of thoracoabdominal aortic aneurysms (TAAAs) is associated with significant postoperative morbidity and mortality. Reperfusion of acutely ischemic abdominal viscera in animals leads to release of multiple factors that cause local and distant organ damage, and similar phenomena occurring in humans after TAAA repair could contribute to the high morbidity/mortality and cost associated with this procedure. METHODS: Twenty-nine patients undergoing elective TAAA repair were studied prospectively. Preoperative organ dysfunction and intraoperative risk factors (cross-clamp time, blood loss, operative time) were assessed and compared with postoperative organ dysfunction (defined as: pulmonary, positive pressure ventilation for > 7 days; renal, increase in serum creatinine > 2.0 mg/dL over baseline; hepatic, lactate dehydrogenase > 500 international units and total bilirubin > 3.0 mg/dL or serum transaminase level > 200 international units; hematopoietic, platelet count > 50 K or leukocyte count > 4.5 K, mortality, and costs. RESULTS: No relationship between preoperative organ dysfunction, blood loss, or operative time and postoperative organ dysfunction or mortality was seen; however, cross-clamp times > 40 minutes were associated with a significantly greater incidence of pulmonary (59%), renal (47%), hepatic (35%), and hematopoietic (47%) dysfunction. In addition, multiple-organ dysfunction (> 2 organ systems) was more common after > 40 minutes of visceral ischemia and led to significantly greater overall hospital ($88,465 + $76,155 vs. $41,782 + $31,244) and intensive care unit ($26,726 + $28,256 vs. $11,234 + $12,146) costs (p < 0.01, Mann-Whitney U test). Mortality associated with leukopenia was 67% compared with 4% without leukopenia (p < 0.01). CONCLUSION: Increasing durations of acute visceral ischemia led to significant multiple organ dysfunction after TAAA repair. Methods of limiting visceral ischemia or the systemic effects of visceral ischemia may decrease both the morbidity and mortality and the overall hospital cost associated with this procedure.

Abdomen↗
PubMed1995

Should the freehand allograft be abandoned as a reliable alternative for aortic valve replacement?

Cryopreserved aortic allografts were used for aortic valve replacement in 80 patients between 1986 and 1994 (infracoronary in 46 and complete root replacement in 34). Hospital mortality was 6.3% (5/80) with all deaths occurring in the infracoronary group. Three of five deaths were in patients with endocarditis and valve ring abscess. Left ventricular-aortic mean pressure gradients across the allograft valves were significantly lower for root replacement patients (mean, 9.0 +/- 6.9 mm Hg versus 18.1 +/- 8.7 mm Hg for infracoronary patients) (p = 0.0001). No patient having root allograft replacement had early echocardiographic aortic insufficiency greater than grade 1 versus 28% of those having infracoronary implantations. Late aortic insufficiency of grade 2 or greater was seen in 46% of patients having infracoronary implantation versus 17% of patients having root implantation. Nine patients had explantation of an aortic allograft (eight infracoronary and one root). Reasons for explantation were as follows: endocarditis (three infracoronary, one root), technical (three infracoronary), undiagnosed idiopathic hypertrophic subaortic stenosis (1 patient), and prolapsing infracoronary leaflet (1 patient). Actuarial freedom from grade 3 and 4 aortic insufficiency or explantation was 77% at 7 years for infracoronary implantations. We conclude that the infracoronary aortic allograft has an unacceptable frequency of late insufficiency and its use in this position should be abandoned. The substantial incidence of late endocarditis in the infracoronary (free-hand) aortic allograft was surprising.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Prospective, randomized trial of retrograde warm blood cardioplegia: myocardial benefit and neurologic threat.

From March 1991 through July 1992, 1,001 patients having elective coronary artery bypass grafting were randomized to receive either continuous warm (> or = 35 degrees C) blood cardioplegia with systemic normothermia (> or = 35 degrees C) or intermittent cold (< or = 8 degrees C) oxygenated crystalloid cardioplegia and moderate systemic hypothermia (< or = 28 degrees C). Preoperative variables including age, sex, prior coronary bypass grafting, hypertension, prior myocardial infarction, diabetes, angina class, and preoperative heart failure class were similar in both groups, as were the intraoperative variables of number of coronary grafts, mammary artery use, and cardiopulmonary bypass time. Aortic cross-clamp time was significantly longer in the warm group (46 +/- 23 minutes versus 40 +/- 21 minutes). Most postoperative variables including mortality (warm, 1.0%, and cold, 1.6%), Q wave infarction (warm, 1.4%, and cold, 0.8%), and need of an intraaortic balloon pump (warm, 1.4%, and cold, 2.0%) were similar between groups. Total neurologic events (warm, 4.5%, and cold, 1.4%; p < 0.005) and perioperative strokes (warm, 3.1%, and cold, 1.0%; p < or = 0.02) were significantly higher in the warm group. Neurologic events included perioperative stroke (warm, 15 patients, and cold, 5 patients; p < 0.02), perioperative encephalopathy (warm, 2 patients, and cold, 1 patient), and delayed (> or = 3 in-hospital days) stroke (warm, 5 patients, and cold, 1 patient). All patients experiencing a stroke had a persistent neurologic deficit at the time of discharge. Encephalopathy resolved completely in all instances.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Megaaorta and aortoiliac obstruction: alternate method of cannulation.

The case of a 69-year-old man with aneurysms of the ascending aorta, transverse aortic arch, and thoracoabdominal aorta combined with coronary artery disease, aortic insufficiency, and severe aortoiliac occlusive disease is presented. Femoral arterial cannulation was contraindicated owing to the aortoiliac disease. Successful surgical treatment is described using an alternate method of cannulation and perfusion.

Aged↗
PubMed1991

Lung glutamine flux following open heart surgery.

Despite the attenuated skeletal muscle proteolysis that occurs following hypothermic anesthesia and open heart surgery, blood amino acid levels are maintained, suggesting enhanced amino acid release by another organ. To investigate the role of the lung in this response, we determined the release of glutamine (Gln) and alanine by the lung, since these two amino acids transport two-thirds of circulating amino acid nitrogen. Three groups of patients were studied: (a) preoperative non-stressed controls; (b) postoperative general surgical patients; and (c) postoperative cardiac surgical patients studied on Postoperative Day 1 following open heart surgery requiring cardiopulmonary bypass and hypothermic anesthesia. In preoperative controls the lung was an organ of glutamine and alanine balance. These exchange rates were unaffected by the stress of an abdominal surgical procedure despite a mild increase in pulmonary blood flow. However, lung Gln release in the cardiac surgical patients was significantly increased (-0.6 +/- 1.2 mumole/kg/min in controls vs -6.5 +/- 1.3 mumole/kg/min in postoperative hearts, P less than 0.05) and was due exclusively to an increase in the pulmonary artery-systemic arterial concentration difference. Alanine release by the lungs was also increased in the postoperative cardiac surgical patients. The mechanism by which this augmented pulmonary glutamine release occurs following open heart surgery is unclear, but the lungs appear to play a central role in maintaining amino acid homeostasis. This metabolic role of the lungs following hypothermic anesthesia and cardiopulmonary bypass has not been previously described.

Amino Acids↗
PubMed1991

Perivalvular pseudoaneurysm complicating bacterial endocarditis: MR detection in five cases.

Bacterial endocarditis usually affects the valve leaflets, but erosion into the valve anulus and adjacent myocardium may form a myocardial abscess. Perivalvular abscesses can drain into the ventricles or aorta, forming a life-threatening pseudoaneurysm. We reviewed our experience with cardiac MR imaging of this disorder. Fourteen patients with complicated bacterial endocarditis underwent ECG-gated spin-echo cardiac MR imaging in addition to conventional duplex two-dimensional echocardiography (2-D echo). Angiography was performed in seven patients, six of whom underwent surgery for valve replacement. MR imaging detected the pseudoaneurysms in all five of the surgically proved cases, while 2-D echo detected only three. Clinical follow-up suggested there were no false-negative examinations, but no autopsy data were available for confirmation. Postoperative MR imaging studies were conducted in three patients, revealing two recurrent pseudoaneurysms and one thrombosed aneurysm. Cardiac MR imaging provides useful pre- and postoperative information in patients with perivalvular pseudoaneurysms due to endocarditis.

Aneurysm, Infected↗
PubMed1990

Accelerated lung amino acid release in hyperdynamic septic surgical patients.

Amino acid flux across the lungs was studied in humans to gain further insight into the altered nitrogen metabolism that characterizes catabolic disease states. Lung flux of glutamine, glutamate, and alanine was determined in three groups of surgical patients with indwelling pulmonary artery catheters: (1) preoperative controls (n = 14), (2) postoperative elective general surgical patients (n = 10, and (3) hyperdynamic septic surgical patients (n = 17). In controls the lung was an organ of amino acid balance. These exchange rates did not change in general surgical patients. In the septic group, glutamine release by the lung increased markedly from a control value of 0.80 +/- 0.99 mumol/kg per minute to 6.80 +/- 1.32 mumol/kg per minute. This accelerated release rate was secondary to both an increase in total pulmonary blood flow and an increase in the pulmonary artery-systemic arterial concentration difference. The lung also became an organ of significant alanine release in septic patients. The lung plays an active metabolic role in the processing of amino acids and may be a key regulator in interorgan nitrogen flux after major injury and infection.

Alanine↗
PubMed1988

The impact of renal fusion and ectopia on aortic surgery.

This article is concerned with observations in 17 patients with renal fusion and ectopic abnormalities: horseshoe kidney in 13 patients, crossed ectopia with fusion in two, pancake kidney in one, and pelvic kidney in one. Three patients had occlusive disease, one may have had renal artery occlusion, and 13 had aneurysms--three thoracoabdominal and 10 infrarenal. Rupture of aneurysm had occurred in one patient at each level and six patients had had one or more previous attempts at aneurysmal removal. Diagnosis and evaluation were made with the aid of intravenous pyelography, retrograde pyelography, CT scanning, and at operation (three patients). Three patients had two normally located right and left renal arteries. Twelve patients had one to three additional aberrant arteries arising from the aorta and iliac arteries. One patient's renal blood supply arose from multiple aberrant arteries. Ureters crossed the midline in two patients. Treatment of occlusive disease consisted of endarterectomy in one patient and percutaneous transluminal angioplasty in two. Aneurysms were treated by graft replacement with retroperitoneal exposure in seven patients and transabdominal exposure in six. One patient was treated medically. Renal isthmus division was employed in only two patients and involved accessory arteries were reattached to the grafts in all cases. Death from myocardial infarction occurred in two patients (12%). Eleven patients subjected to operation were alive 6 months to 14 years later.

Aged↗
PubMed1987

Management of combined pancreatoduodenal injuries.

From 1969 to 1985, 129 patients with combined pancreatoduodenal injuries were treated at one urban trauma center. A total of 104 patients (80.6%) had penetrating wounds, and multiple visceral and vascular injuries were usually associated with the pancreatoduodenal injury. Primary repair or resection of one or both organs coupled with pyloric exclusion and gastrojejunostomy (68 patients) and drainage was used in 79 patients (61.2%) in the entire study and in 59% (36 of 61) of all patients treated since 1976. Simple primary repair of one or both organs and drainage was performed in 31 patients (24%), whereas the remaining 19 patients (14.8%) had pancreatoduodenectomies (13 patients) or no repair before exsanguination (six patients). Major pancreatoduodenal complications occurring in the 108 patients surviving more than 48 hours included pancreatic fistulas (25.9%), intra-abdominal abscess formation (16.6%), and duodenal fistulas (6.5%). The overall mortality rate for the study was 29.5% (38 of 129). The acute mortality rate with these injuries will remain high secondary to injuries to associated organs and vascular structures. The morbidity and late mortality rates related to the moderate to severe pancreatoduodenal injury itself can be decreased by the addition of pyloric exclusion and gastrojejunostomy to the primary repairs.

Abdomen↗
PubMed1985

Prosthetic grafts in vascular trauma: a controversy.

Refinements in vascular surgery have made repair of arterial injuries common throughout the world. There seems to be little doubt among trauma surgeons that primary repair of arterial injuries is the method of choice, as long as there is little devitalized arterial tissue and the procedure can be accomplished without tension on the suture lines or stenosis at the repair. When a lateral repair or primary anastomosis is not feasible, the type of conduit to be used is still the subject of controversy. Most clinical reports within the past 30 years state that autogenous vein is the grafting material of choice in traumatic wounds. However, the most recent investigations of the data do not favor autogenous vein grafts and, in fact, may lean toward prosthetic materials as the most satisfactory conduits for repairing traumatized arteries.

Biocompatible Materials↗
PubMed1984

Blunt cardiac rupture.

Blunt injury to the heart ranges from contusion to disruption. This report comprises 14 patients seen during a 6-year period with cardiac rupture secondary to blunt trauma. Eight patients were injured in automobile accidents, two patients were injured in auto-pedestrian accidents, two were kicked in the chest by ungulates, and two sustained falls. Cardiac tamponade was suspected in ten patients. Five patients presented with prehospital cardiac arrest or arrested shortly after arrival. All underwent emergency department thoracotomy without survival. Two patients expired in the operating room during attempted cardiac repair; both had significant extracardiac injury. Seven patients survived, three had right atrial injuries, three had right ventricular injuries, and one had a left atrial injury. Cardiopulmonary bypass was not required for repair of the surviving patients. There were no significant complications from the cardiac repair. The history of significant force dispersed over a relatively small area of the precordium as in a kicking injury from an animal or steering wheel impact should alert the physician to possible cardiac rupture. Cardiac rupture should be considered in patients who present with signs of cardiac tamponade or persistent thoracic bleeding after blunt trauma.

Adolescent↗
PubMed1983

Severe duodenal injuries. Treatment with pyloric exclusion and gastrojejunostomy.

During a 12-year period, 313 patients with duodenal injuries were treated. Primary repair, pyloric exclusion, and gastrojejunostomy were used in 128 patients (41%) with severe duodenal and pancreaticoduodenal injuries, to reduce "duodenal" morbidity and mortality. The duodenal fistula rate was 2.2% overall, and 5.5% in the patients undergoing exclusion. Only two deaths were due to fistulas. Forty-two patients underwent upper gastrointestinal tract examinations after operation. In patients examined 21 days or more after operation, 94% had a patent pylorus. Marginal ulceration was infrequent (four patients), as were complications associated with the procedure (3%). Pyloric exclusion with gastrojejunostomy is a quick and simple procedure that allows return of pyloric patency and is associated with a low incidence of duodenal fistulas. When fistulas do develop, they are usually easily controlled and are associated with a low mortality. We believe pyloric exclusion with gastrojejunostomy to be the procedure of choice in patients with severe duodenal and pancreaticoduodenal trauma.

Adolescent↗