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Biomedical subjects

W H Snyder

Publications and source records attributed to W H Snyder.

At least 19 recordsLinked to original sources
PubMed1992

Pelvic abscess or pseudoaneurysm: diagnostic and therapeutic dilemma following iliac arterial trauma.

Intra-abdominal abscesses often complicate operations for abdominal trauma and are particularly dangerous in patients whose injuries involve major vessels. We report our experience with 10 patients who developed pelvic abscesses among 75 survivors of iliac arterial injuries. Pseudoaneurysms of primarily repaired iliac arteries occurred in 8 of these 10 patients. Emergency operations were required for acute arterial thrombosis or hemorrhage in four patients; massive hemorrhage that complicated the drainage of pelvic abscesses led to the recognition of the pseudoaneurysms in the other four patients. Three of the eight patients with pseudoaneurysm died of postoperative complications; ischemic extremity sequelae occurred in all five survivors. The association of pelvic abscesses with the complications iliac arterial repairs has not been previously emphasized. The integrity of an arterial repair should be arteriographically confirmed before proceeding with drainage of a pelvic abscess that developed after iliac arterial trauma.

Abscess↗
PubMed1992

Mineral metabolic effects of thyroidectomy and long-term outcomes in a family with MEN 2A.

We have followed a family with multiple endocrine neoplasia type 2A for 18 years. Four members have undergone total thyroidectomy for medullary thyroid carcinoma or C-cell hyperplasia, and one has required bilateral adrenalectomy for pheochromocytoma. None has developed hypercalcemic hyperparathyroidism, although parathyroid hormone levels were relatively high prethyroidectomy and fell postoperatively in the patients with high calcitonin levels. In three of the four cases, intestinal calcium absorption decreased following thyroidectomy.

Adrenal Gland Neoplasms↗
PubMed1992

Penetrating abdominal aortic trauma: a report of 129 cases.

The clinical presentation, resuscitation, and operative management of 129 patients with penetrating injuries to the abdominal aorta treated between 1960 and 1989 were reviewed. This is the largest reported civilian or military experience with this specific injury; our review of the literature was limited to reports focusing on the detailed analysis of the management and outcome of aortic trauma. Eighty-two percent of patients were in shock; 18 patients (14%) underwent emergency room thoracotomies, with no survivors. Of 46 patients requiring operating room thoracotomies, only 20% survived. All patients underwent exploration. Thirty percent had three or more visceral injuries; only 2% had no concurrent visceral injury. There were associated vascular injuries in 58% of patients, the inferior vena cava being the most frequent (37%). The most significant predictor of death was continued bleeding at operation. Ninety percent of patients with free intraperitoneal bleeding died, in contrast to 35% with a contained retroperitoneal hematoma (p less than 0.001). Aortic injuries were supraceliac in 25% of patients, between the celiac and renal arteries in 25%, and infrarenal in 50%. The respective mortality rates were 70%, 80%, and 47% (p less than 0.05). Repair of the aortic defect was possible in 103 patients (80%). The most common repair was lateral arteriorrhaphy in 53% of patients, followed by end-to-end anastomosis in 15% and prosthetic repairs in 8%. The overall mortality rate was 62%, which is similar to that of previous reports. Despite advances in trauma care, a functioning paramedic system, and the use of aggressive means to obtain aortic control, penetrating aortic trauma remains highly lethal.

Adult↗
PubMed1992

Pheochromocytoma with extension into the inferior vena cava: a case report.

Eleven cases of pheochromocytoma with extension into the inferior vena cava have been reported previously. This report describes a case of a right adrenal pheochromocytoma with extension into the inferior vena cava that was removed with the aid of cardiopulmonary bypass and circulatory arrest.

Adrenal Gland Neoplasms↗
PubMed1990

Multiple nonatherosclerotic aneurysms unrelated to a clinical syndrome.

Two cases of multiple inflammatory aneurysms in young patients without evidence of autoimmune disease or an aneurysmal syndrome are presented. Neither case showed any clinical or histologic characteristics typical of Ehlers-Danlos syndrome, Marfan's syndrome, Takayasu's arteritis, or other aneurysmal syndromes. Pathologic findings showed adventitial and medical destruction in both patients; although the first case displayed more adventitial involvement, the second showed greater destruction of the medial elastic laminae. The decision to repair an aneurysm should be tempered by its location, the amount of involvement of the artery with multiple lesions, and the risk to the end-organ if repair is unsuccessful.

Adult↗
PubMed1988

Subxiphoid pericardial window and penetrating cardiac trauma.

Between 1982 and 1986, 108 patients with penetrating wounds in proximity to the heart and no obvious signs of cardiac injury underwent a diagnostic subxiphoid pericardial window procedure. Eighty-four patients had stab wounds, 22 had gunshot wounds, and two had shotgun wounds. The subxiphoid pericardial window procedure produced positive results in 30 patients (28%) and negative results in 78 patients (72%). There were two false-positive subxiphoid pericardial window procedures. Eleven patients (39%) with cardiac injuries were not hypotensive and did not have signs or symptoms of cardiac injuries prior to the subxiphoid pericardial window procedure. When they were obtained (n = 80), electrocardiograms were abnormal in 57% and 21% of patients with and without cardiac injuries, respectively. At thoracotomy, 28 patients had injuries (ventricle, 20; atrium, three; and pericardium, five) and 21 required suture repair. Thirty-nine patients underwent a concomitant laparotomy. Forty-six abdominal visceral injuries were identified in 28 patients, including 21 hollow viscus injuries. There was no significant short-term or long-term morbidity (eg, pericarditis, tamponade, or post-pericardiotomy syndrome) attributable to the subxiphoid pericardial window procedure. There were no known missed cardiac injuries, and there were no deaths in the series. Some patients with penetrating wounds to the heart have no overt signs or symptoms of cardiac injury. A subxiphoid pericardial window procedure quickly identifies or excludes cardiac injuries and can be performed with minimal morbidity, even when there is contamination from the gastrointestinal tract.

Abdominal Injuries↗
PubMed1988

Popliteal and shank arterial injury.

Arterial injuries below the adductor hiatus in the lower extremity result in amputation more often than do injuries in any other site. The major deterrents to limb salvage are delay in diagnosis and revascularization and extensive adjacent bone and soft-tissue trauma. Rapid diagnosis and repair are needed for all popliteal artery injuries and for infrapopliteal injuries that compromise distal flow. The optimal management of asymptomatic injuries of single shank arteries with normal flow in uninjured parallel vessels is not defined.

Amputation, Surgical↗
PubMed1987

A decade of lower extremity venous trauma: patency and outcome.

Eighty-two patients with infrailiac venous injuries were reviewed. Veins were repaired in 75 patients and ligated in 7 patients. Clinical outcome could be correlated with anatomic patency for 41 patients who had postoperative venograms. Sixty-three percent of the repairs proved to be patent. Simple repairs were successful more often than complex ones. Site of injury and perioperative therapeutic adjuncts did not affect results. Eleven limbs were amputated, none solely because of venous injury. Edema was present at last follow-up in fewer patients with patent repairs than occluded repairs or ligations. Repair of major lower extremity venous injuries should be attempted routinely in stable patients. Improved patency of complex repairs may require increased use of balloon catheter thrombectomy and other adjunctive procedures. Postoperative venography is very useful for the evaluation of results.

Adolescent↗
PubMed1987

Diagnosis of penetrating cervical esophageal injuries.

Arterial injuries pose the greatest early threat to the patient with penetrating neck trauma and esophageal injuries, the greatest late threat. Clinical evaluation reliably identifies 80 percent of esophageal injuries, which, in our opinion, is not adequate. In 118 minimally symptomatic or asymptomatic patients with penetrating neck trauma, the combination of esophagography with esophagoscopy identified all 10 esophageal injuries in 118 patients with penetrating neck trauma. These data suggest that patients with penetrating neck trauma and minimal clinical findings should be initially evaluated with arteriography and esophagography. If the results of arteriography or esophagography are positive, then neck exploration should be performed. If the results of esophagography are equivocal, then rigid esophagoscopy should be performed. If all test results are negative, then observation is justified.

Adult↗
PubMed1985

Early steroid therapy for respiratory failure.

We performed a randomized double-blind trial to determine the usefulness of early methylprednisolone therapy for patients with pulmonary failure. We selected 81 acutely ill, mechanically ventilated patients at high risk for adult respiratory distress syndrome (ARDS). Thirty-nine patients received methylprednisolone, 30 mg/kg, every six hours for 48 hours; 42 patients received mannitol placebo. All patients were given a positive end-expiratory pressure of 5 cm H2O, monitored with pulmonary artery catheters, and treated for their primary disease processes. Twenty-five steroid-treated patients (64%) and 14 placebo-treated patients (33%) developed ARDS. Early infectious complications occurred in 30 steroid-treated patients (77%) and 18 placebo-treated patients (43%). There were no significant differences in factors predisposing to ARDS, ventilatory requirements, or days of intensive care. These results do not support the use of methylprednisolone for ARDS. Steroids failed to improve pulmonary function and were associated with an increased infection rate. Intensive pulmonary and general supportive care remain the preferred therapy for ARDS.

Adult↗
PubMed1984

Civilian arterial trauma of the upper extremity. An 11 year experience in 267 patients.

Two hundred ninety-eight arterial injuries in 269 upper extremities were reviewed. Penetrating agents accounted for 250 injuries (93 percent) and blunt trauma for 19 (7 percent). Fifty-nine axillary, 126 brachial, 65 radial, and 48 ulnar arteries were damaged. Twenty-six extremities had more than one artery injured. The initial vascular examination revealed no abnormalities or was equivocal in 16 percent of all patients and in 32 percent of those with axillary artery injuries. Adjacent upper extremity structures were injured in 195 limbs (73 percent). Resection and primary anastomosis (54 percent) or vein interposition grafting (26 percent) were the most frequent methods of repair. Two deaths (0.7 percent) occurred and four amputations (1.5 percent) were required. Distal pulses were present at discharge in 93 percent of the evaluable extremities. Despite excellent success with arterial reconstruction, functional results were limited by associated nerve injuries. One hundred fifty patients (49 percent) had nerve deficits at discharge, and 71 (27 percent) had serious functional limitations.

Adolescent↗
PubMed1983

Mortality and renal salvage after renovascular trauma. A review of 94 patients treated in a 20 year period.

Ninety-four patients with 96 renovascular injuries underwent operations over a 20 year period. Forty-nine patients had renal artery injury, 45 had isolated venous injury, and 33 had both vessels injured. Arterial revascularization succeeded in four patients, failed in five, and the results were not documented in three. Revascularization of acute renal artery thromboses was unsuccessful. Isolated renal vein injuries were repaired in 28 patients. The mortality rate was 37 percent for renal artery injuries and 28 percent for isolated renal vein injuries, despite the frequent choice of nephrectomy instead of reconstruction in unstable patients. Renal salvage was accomplished in 10 percent of patients with renal artery injury and in 51 percent of patients with isolated renal vein injury. Renal salvage is not often feasible in patients with renal arterial injuries because of associated renal vein injuries. The success of revascularization of traumatically occluded renal arteries is low and should probably be attempted only in unusual circumstances, such as bilateral injuries. Most isolated renal vein injuries are repairable, and reconstruction should be attempted in stable patients.

Adolescent↗
PubMed1983

Arterial injuries below the knee: fifty-one patients with 82 injuries.

Clinical features of tibial and peroneal artery injuries are characterized in a review of 51 patients with 82 injured arteries. Injuries were penetrating in 34 (67%) patients and blunt in 17 (33%). Physical findings suggested arterial injuries in 42 (82%) patients, but nine had no signs of vascular trauma. Nineteen patients with no palpable distal pulses had average preoperative delays of nearly 5 hours, suggesting a lack of appreciation for the morbid potential of these injuries. Operations included ligations of single-vessel injuries and arterial reconstructions in the 21 (41%) patients with two or more injured vessels. Amputations were necessary in eight (16%) patients. Limb loss was more frequent with blunt trauma (23%), shotgun wounds (33%), initial absent pulses (32%), and three injured vessels (60%). The frequency of limb loss with these injuries emphasizes the importance of early diagnosis, expedient operation, and thorough revascularization.

Adolescent↗
PubMed1982

Diffusion in the vicinity of standard-design nuclear power plants--I. Wind-tunnel evaluation of diffusive characteristics of a simulated suburban neutral atmospheric boundary layer.

A large meteorological wind tunnel was used to simulate a suburban atmospheric boundary layer. The model-prototype scale was 1:300 and the roughness length was approximately 1.0 m full scale. The model boundary layer simulated full scale dispersion from ground-level and elevated release points over surfaces of comparable roughness length. This information should prove useful in a variety of transport and diffusion studies over short to moderate downwind distances. It will be used in Part II as the baseline data set with which to compare diffusion downwind of standard-design nuclear power plants.

Air Pollution, Radioactive↗
PubMed1982

Diffusion in the vicinity of standard-design nuclear power plants--II. Wind-tunnel evaluation of building-wake characteristics.

Laboratory experiments were conducted to simulate radiopollutant effluents released to the atmosphere from two standard-design nuclear power plants. The main objective of the study was to compare the dispersion in the wakes of the plants with that in a simulated atmospheric boundary layer. Dispersion functions are determined that describe the spread of the effluent plume in the wake of each plant. These dispersion functions are described by power laws. They are determined for three incident wind angles and the number of stacks associated with each plant. Lateral plume spread was directly related to the silhouette area of the plants. A graphical technique is presented relating the lateral dispersion to the associated silhouette area of the building or building complex.

Air Pollution, Radioactive↗
PubMed1982

Vascular injuries near the knee: an updated series and overview of the problem.

Injury of the popliteal artery results in amputation more often than any other arterial injury. Adjacent injuries, small vessel thrombosis, and muscle necrosis are the major deterrents to limb salvage. This report updates a previously published series, expanded to include 110 injuries treated during a 14-year period. Emphasis is placed on the management of adjacent injuries, errors promoting amputation, and principles of improving limb survival. The hallmark of success is the rapid and complete restoration of arterial and venous flow.

Adolescent↗
PubMed1981

Cimetidine vs antacid in prophylaxis for stress ulceration.

Seven-seven critically ill patients were prospectively randomized into four groups to compare antacids and various doses of cimetidine in the neutralization of gastric acid for preventing complications of stress ulcers. Gastric pH was monitored hourly, basing the efficacy of neutralization on preselected pH values for each study group. Cimetidine provided adequate neutralization in 14 (23%) of 61 patients. Gastric acid in all 16 patients treated with antacids was adequately neutralized. Stress bleeding occurred in three (5%) patients treated with cimetidine and in no patient treated with antacids. Reversible thrombocytopenia developed in six (26%) of 23 patients treated with 2,400 mg/day of cimetidine. Hourly monitoring of gastric pH is a mandatory component in the prevention of stress bleeding. Antacid is the preferred agent for gastric acid neutralization because it is more effective, safer, and less expensive.

Adolescent↗