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Biomedical subjects

G D Williams

Publications and source records attributed to G D Williams.

At least 91 records · Page 5Linked to original sources
PubMed1979

Identification of heparin resistance during cardiac and vascular surgery.

An investigation of the response of the activated clotting time to systemic heparinization during cardiopulmonary bypass and peripheral vascular surgery was prompted by the death from clotting of a patient with endocarditis while undergoing valve replacement. The activated clotting time during cardiopulmonary bypass was thereafter maintained at 300 to 400 seconds. Consumption of heparin sodium, derived from an individual dose-response curve, was 0.01 to 3.86 units/kg/min. There was no correlation between initial heparin resistance and the subsequent rate of consumption. Some patients undergoing peripheral vascular surgery required additional heparin after an initial standard dose of 8,000 units so as to maintain their activated clotting time at twice the control values. These data are discussed in relation to previous articles, and recommendations are made for adequate intraoperative heparinization.

Adolescent↗
PubMed1979

Pulsatile perfusion versus conventional high-flow nonpulsatile perfusion for rapid core cooling and rewarming of infants for circulatory arrest in cardiac operation.

Thirty consecutive infants undergoing hypothermia and circulatory arrest for repair of ventricular septal defect, transposition of the great vessels, or atrioventricular canal defects were alternately selected for conventional high flow nonpulsatile perfusion or pulsatile perfusion during core cooling and rewarming. All received morphine anesthesia, 30 mg/kg of Solu-Medrol, and 10 to 15 mcg/kg of phentolamine. Those receiving nonpulsatile flow were perfused at a rate of 160 to 180 cc/kg/min with a roller pump and oxygenator with arterial pressure of 50 to 55 mm Hg. In the pulsatile flow group, a roller pump and oxygenator were used, and an especially constructed Datascope PAD (pulsatile assist device) was interposed in the arterial line to provide pulsatile perfusion with 75/40 mm Hg pressure at slightly reduced flow (150 cc/kg/min). The average rectal, esophageal, and tympanic membrane temperatures were reduced to approximately 16 degrees C prior to circulatory arrest. Following repair, perfusion was resumed until these temperatures returned to 37 degrees C. Cooling and rewarming were enhanced by pulsatile perfusion, with over 30% reduction in total pump time. Additionally, the larger patients in the pulsatile group cooled almost as rapidly as the smaller. The rates of decline and subsequent rise of rectal, esophageal, and tympanic membrane temperatures were equal in the pulsatile group, but the rectal temperature lagged far behind in the nonpulsatile group. Urine production during bypass was 100% greater in the pulsatile group. The plasma free hemoglobin was similar in both groups. The average postrewarming pH was 7.31 in the nonpulsatile group and 7.42 in the pulsatile group. Infants receiving pulsatile flow awakened more quickly, were more alert, and required less postoperative mechanical ventilation. We suggest that pulsatile perfusion for core cooling and rewarming of infants is safe and is more rapid and physiological than conventional high-flow nonpulsatile perfusion.

Acid-Base Equilibrium↗
PubMed1977

Naturally occurring trypanosomiasis (Chagas' disease) in dogs.

Nine fatal cases of canine American trypanosomiasis (Chagas' disease) were encountered from November, 1972, through November, 1975. Of the 9 cases, 7 occurred in dogs from 5 central Texas counties, and all but one case was diagnosed during the months of September, October, or November. The source of infection was discovered in only one case--that being a doghouse heavily infested with Triatoma lectularius occulta. Each of 6 bugs collected had infective forms of the protozoan, Trypanosoma cruzi. Trypanosomiasis usually is not considered in the differential clinical diagnosis of cardiac dysfunction in man or other mammals in the United States. An antemortem diagnosis was made in only 1 of the 9 dogs, with diagnosis in the remaining dogs being made at necropsy. The predominant microscopic lesion in all dogs was necrotizing granulomatous myocarditis associated with the amastigotes of T cruzi.

Animals↗
PubMed1977

Treatment of corrosive burns of the esophagus.

Forty patients with caustic ingestion have been treated between 1955 and 1975. Strong alkali was the corrosive in 95%, and 80% were under 10 years old. Early esophageal stricture developed in 18 patients four weeks after lye ingestion. Among these, esophageal bougienge restored an adequate lumen in two patients with short, soft annular strictures, and right colon interposition was used for esophageal subsitution in ten who had long, dense strictures. We recommend early diagnostic esophagoscopy, to the uppermost level of burn injury only, to determine the presence and severity of the esophageal injury. If esophagoscopy reveals esophageal burn injury, corticosteroid and antibiotic therapy are continued. If no burn injury is visualized, the patient is spared unnecessary treatment. Long, dense strictures unresponsive to bougienage place the patient at risk from instrumental perforation, and these patients should undergo colon interposition through a substernal extrapleural tunnel.

Adolescent↗
PubMed1977

Successful extraction of intracardiac tumor thrombus of renal carcinoma.

Successful management of a patient with an intracardiac tumor thrombus of renal carcinoma is described. Important considerations in the management include precise localization of the upper limits of the tumor thrombus preoperatively, early ligation of the renal artery, control of the circulation through the inferior vena cava by temporary occlusion of the vena cava below the renal veins, the left renal vein and the hepatic circulation, and a team approach, using the expertise of the urologist and the cardiac surgeon, as well as cardiopulmonary bypass.

Cardiopulmonary Bypass↗
PubMed1976

Retrograde venous cardiac perfusion for myocardial revascularization: an experimental evaluation.

This study evaluates cardiac function in dogs during retrograde perfusion through the coronary sinus. Five hearts perfused retrograde in an ex vivo apparatus demonstrated rapid and marked increases in weight and perfusion pressure, became hemorrhagic, and contracted poorly within one hour. Five similarly perfused hearts treated with phenoxybenzamine experienced no increase in weight or perfusion pressure and maintained good color and contractions for up to one hour. Five additional hearts treated with phenoxybenzamine did not develop hemorrhage, edema, increased weight, or increased perfusion pressure but could maintain the systemic circulation for only brief periods after 15 minutes of intermittent cardiopulmonary bypass support. We conclude that cardiac viability can be maintained with retrograde perfusion enhanced with alpha blocking agents. However, hearts so perfused cannot maintain adequate systemic pressure. The data suggests that extensive myocardial revascularization through the retrograde venous route would be ineffective.

Animals↗
PubMed1976

Peripheral arterial injuries: a reassessment.

Ninety-four patients with peripheral arterial injuries were subjected to acute repair, negative exploration, or late repair of the complications of the arterial injury (false aneurysm, A-V fistula, and/or limb ischemia). The causes of failure after acute injury include extensive local soft tissue and bony damage, severe concomitant head, chest or abdominal wounding, stubborn reliance on negative arteriograms in patients with probable arterial injury, failure to repair simultaneous venous injuries, or harvesting of a vein graft from a severely damaged extremity. There is a positive correlation between non-operative expectant treatment and the incidence of late vascular complications requiring late arterial repair. Delayed complications of arterial injuries occurred most frequently in wounds below the elbow and knee.

Adolescent↗
PubMed1976

Left ventricular--right atrial shunt: an unusual cause of hemodynamic deterioration following aortic valve surgery.

Two cases of left ventricular-right atrial shunts inadvertently produced during aortic valve replacement are described. It is surprising that this complication is not more prevalent considering the close proximity of the aortic and mitral valves to the atrioventricular portion of the membranous septum. A left-to-right shunt should be a consideration in patients who fail to improve following aortic valve surgery, especially if the valve and subaortic region were heavily calcified or septal trauma occurred during the surgical procedure.

Adult↗
PubMed1975

The relative merits of the heparin-bonded shunt vs. femerofemoral bypass for aortic arch injury.

Six patients with traumatic aortic arch injuries have been repaired with distal aortic perfusion maintained with femerofemoral bypass (three patients) and the heparin-bonded ascending aorta-to-femoral artery shunt (three patients). The two groups are compared regarding pre- and postoperative changes in blood urea nitrogen, creatinine and platelet counts, as well as required blood replacement, days in the hospital, and rapidity of setting up the technique of distal aortic perfusion. No significant difference in the two techniques was demonstrated regarding the above parameters. Both the heparin-bounded shunt and femoral vein-to-femoral artery bypass with the pump oxygenator provide acceptable spinal cord and renal protection. The two techniques should be equally rapid and safe for the larger institution employing cardiopulmonary bypass procedures on a routine basis. The heparin-bounded shunt, however, may provide a more rapid and reliable means of lower aortic perfusion for the smaller institution with less available means of cardiopulmonary bypass support.

Accidents, Traffic↗