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Biomedical subjects

F L Grover

Publications and source records attributed to F L Grover.

At least 145 records · Page 8Linked to original sources
PubMed1981

Objective evaluation of the efficacy of various venous cannulas.

Six venous cannulas (USCI No. 32, USCI No. 40, USCI No. 44, Sarns No. 40, Sarns two-stage cavoatrial, and Ferguson Argyle No. 40) were tested for efficiency of venous flow during cardiopulmonary bypass, with and without aortic cross-clamping. Each cannula was tested six times in dog models (twice in each of three dogs) and the data were averaged. The tip of the cavoatrial Sarns catheter was positioned as recommended. Two No. 32 USCI caval cannulas were placed either with or without caval snaring. The other cannulas were placed in the right atrium. Arterial flow was constant at 80 ml/kg/min, and aortic pressure averaged 84 mm Hg. Central venous pressure and the right ventricle excluded from the pulmonary artery so that blood which was not drained via the venous cannula was measured. Each single atrial cannula decompressed the right atrium (right atrial pressure 0 to 1 mm Hg) better than two caval cannulas (right atrial pressure 0 to 2 mm Hg). Caval snaring did not empty the right atrium (right atrial pressure 2 to 5 mm Hg) as well as any single cannula. The cavoatrial Sarns catheter did not empty the right atrium as well (right atrial pressure 2 to 4 mm Hg), but drained blood from the inferior vena cava (central venous pressure 0 mm Hg) better than other atrial cannulas (central venous pressure 1 to 5 mm Hg). All of the atrial cannulas performed equally well. The right ventricular vent flow varied between 63 and 70 ml/min with each of the atrial cannulas but rose to 85 ml/min with the cavoatrial Sarns catheter and 190 and 74 ml/min during caval cannulation with and without snaring, respectively. Aortic cross-clamping eliminated coronary sinus flow and decreased right ventricular vent flow. Therefore, a single atrial cannula is more efficient in draining blood from the right side of the heart than are two caval or a cavoatrial cannula. This advantage is negated by aortic cross-clamping.

Animals↗
PubMed1980

Does cardioplegic arrest compromise long-term left ventricular function?

This study was undertaken to evaluate the chronic, long-term effect of global ischemia produced by cold potassium cardioplegia during cardiopulmonary bypass. Fifteen dogs underwent either control thoracotomy and chronic instrumentation(Group A) or cardiopulmonary bypass and 60 minutes of cold cardioplegic arrest (Group B). With the dogs conscious, hemodynamic variables and left ventricular studies were recorded weekly for 12 weeks postoperatively, both at rest and during volume overload with saline solution. At rest, the heart rate in Group B was 18% higher and stroke volume was 14% lower than Group A. With volume overload, cardiac output and maximum rate of rise of left ventricular pressure in Group B rose only from 3.7 +/- 0.6 to 7.1 +/- 0.8 liters per minute and 2,410 +/- 220 to 2,730 +/- 130 mm Hg per second, respectively, compared with 3.9 +/- 0.6 to 10.4 +/- 0.8 liters per minute and 2,740 +/- 230 to 3,890 +/- 350 mm Hg, respectively, in Group A (p less than 0.01). In Group B, the other variables reached a plateau sooner than in Group A (48 versus 110 seconds). The left ventricular function curve showed a mild decrease in functional capacity and depressed contractility. Therefore, one hour of cardioplegic cardiac arrest caused no depression of function at rest. Mild depression of left ventricular function was demonstrated up to 7 weeks postoperatively during acute volume overload.

Animals↗
PubMed1979

Effect of isoproterenol on regional myocardial perfusion and tissue oxygenation in acute myocardial infarction.

The effect of isoproterenol infusion on regional myocardial perfusion and tissue oxygenation during acute myocardial infarction was investigated in anesthetized dogs. Measurements of regional flow with radioactive microspheres and myocardial lactate and adenosine triphosphate from analysis of myocardial biopsies were compared in normal, marginal, and infarcted tissue in dogs with a ligated coronary artery. After 10 minutes of isoproterenol 0.15 microgram/Kg./minute, flow was unchanged in the marginal and infarcted regions, and, although rises occurred in most dogs, changes were inconsistent in the normal regions. In the marginal regions, tissue lactate rose by 5.6 mumoles/g (97 per cent) and adenosine triphosphate fell by 2.4 mumoles/g (46 per cent) after isoproterenol. No consistent changes occurred in the normal or infarcted regions of the dogs given isoproternol or in any regions of control dogs given saline. It is concluded that beta-adrenergic stimulation with isoproterenol increases tissue ischemia in experimental acute myocardial infarction.

Adenosine Triphosphate↗
PubMed1979

Diagnosis and management of major tracheobronchial injuries.

From 1968 to 1978, 14 patients were treated for major tracheal or bronchial injury. Five injuries resulted from blunt trauma and nine from penetrating injury. Of the 5 patients with injury due to blunt trauma, three had avulsions of the right main bronchus from the trachea. In 2 of them, the injury was associated with stellate tears of the distal trachea and bronchus. The simple avulsion was repaired by a primary anastomosis of the right main bronchus to the distal trachea. For the other 2 patients, treatment consisted of right pneumonectomy. The remaining 2 patients in this group had complete transection of the trachea and underwent primary repair. Of the 9 patients with a penetrating injury, 4 had lacerations of the cervical trachea which were treated with neck exploration and tracheostomy. Three patients with partial transections of the cervical or upper mediastinal trachea were treated by primary closure. The other 2 patients had gunshot wounds to the distal right lateral trachea, which were treated by right thoracotomy and primary closure. There were no deaths, and the subsequent course was generally good in all patients.

Adolescent↗
PubMed1979

Effect of therapeutic-dose irradiation on left ventricular function in conscious dogs.

Every week, 8 conscious, chronically instrumented dogs underwent left ventricular (LV) function studies before, during, and after cardiac irradiation with cobalt 60 (myocardial dose of 5,000 rads at 200 rads per day through a 5 X 5 cm port). During the weekly LV function studies, left atrial pressures were raised by rapid infusion of balanced saline solution. Heart rate, aortic pressures, left and right atrial pressures, LV pressure, left ventricular end-diastolic pressure (LVEDP), and maximum rate of rise of LV pressure were recorded. Electrocardiograms were made. Cardiac outputs were obtained by thermodilution. Stroke volume, LV stroke work, and LV minute work were calculated. LV function curves were constructed each week. All dogs lost weight and became irritable after approximately 800 rads. The electrocardiograms showed signs of myocardial injury after 1,200 rads. All variables were slightly depressed during the first 8 weeks following irradiation. At the eleventh week, both left atrial pressure and LVEDP increased significantly and LV function declined. There was also clinical evidence of LV failure at rest and after volume loading. This study documents that external cardiac irradiation, in a therapeutic dose and schedule range, causes depression of LV function. These functional changes were partially reversed when the follow-up study was continued to six months after irradiation.

Animals↗
PubMed1979

Affairs of the wounded heart: penetrating cardiac wounds.

During the 10-year period ending 1 March 1978, 100 consecutive patients with penetrating cardiac wounds entered the Bexar County Hospital with some sign of life. The early and late mortality rate, 11%, declined to 8% during the last 4 years. Noncardiac injuries were responsible for six of the eleven deaths. Complications occurred in 17. The most frequently injured chambers were the right ventricle (46) and left ventricle (30). Sixty-nine patients had stab wounds and 26 had gunshot wounds. Pericardiocentesis was falsely positive or negative in 12 of 47 patients. Two distinct syndromes were apparent, hemorrhagic shock and cardiac tamponade. Patients with shock had immediate thoracotomy. Patients with suspected tamponade had a subxiphoid pericardial window, under local or light general anesthesia, for diagnosis and decompression before endotracheal intubation and sternotomy. Most wounds were repaired by direct suture. Cardiopulmonary bypass and thoracotomy before arrival in the operating room were rarely indicated.

Cardiac Tamponade↗
PubMed1979

Effects of aortic balloon pumping during cardiopulmonary bypass on myocardial perfusion, metabolism, and contractility.

This study was undertaken to determine if the production of pulsatile flow by the intra-aortic balloon pump during cardiopulmonary bypass has any beneficial effect on coronary flow, regional myocardial flow, myocardial metabolism, and left ventricular function. Thirty-six conditioned dogs were subjected to one hour of total normothermic cardiopulmonary bypass. They were divided into the following five groups: (1) controls, beating heart and femoral inflow; (2) balloon, beating heart, and femoral inflow; (3) balloon, beating heart, and aortic inflow; (4) control, fibrillating heart and femoral inflow; and (5) balloon, fibrillating heart, and femoral inflow. Total coronary flow, left ventricular flow, coronary sinus flow, and the endocardial-to-epicardial flow ratio increased in group 3. This increase in flow may have been in part due to increased resistance to flow in the descending aorta by the balloon. No differences in flow were noted in the other groups, all of which were perfused via the femoral artery. No significant differences in myocardial metabolism or left ventricular contractility could be demonstrated between balloon-treated and control groups in these normal hearts.

Adenosine Triphosphate↗
PubMed1979

Effects of systemic hypothermia on myocardial metabolism and coronary blood flow in the fibrillating heart.

Ventricular fibrillation during normothermic cardiopulmonary bypass is deleterious to the myocardium. This study was undertaken to determine if moderate systemic hypothermia would protect the myocardium during ventricular fibrillation. Fourteen mongrel dogs were subjected to 1 hour, 15 minutes of total cardiopulmonary bypass. Ventricular fibrillation was induced by a continuous electrical alternating current applied at the beginning of bypass and lasting for 1 hour. Six animals were maintained at normothermia (Group I), and eight were cooled to 30 degrees C. for 1 hour (Group II). The hypothermic group (Group II) demonstrated lower myocardial oxygen consumption and metabolism, decreased coronary blood flow, and less myocardial lactate production during ventricular fibrillation than did Group I. It is concluded that hypothermia does offer some protection, although not complete, against the deleterious effects of ventricular fibrillation described previously.

Adenosine Triphosphate↗
PubMed1978

Experimental evaluation of reexpansion pulmonary edema.

Reexpansion pulmonary edema following pneumothorax is clinically uncommon but occasionally life threatening. This study documents the functional and anatomical abnormalities that occur when a collapsed lung is reexpanded. Right pneumothorax was created through open tube thoracostomy in 30 goats. The animals were divided into six groups by duration of pneumothorax (24, 48, or 72 hours) and technique of reexpansion (waterseal vs 10 cm H2O suction). Arterial blood gases and alveolar-arterial oxygen tension difference (A-aDO2) were analyzed before pneumothorax and after reexpansion. Each lung was reexpanded for 2 hours, chest roentgenograms were obtained, and both lungs were removed. The left lung served as the control. Both lungs were checked for surfactant activity and pulmonary extravascular water volume (PEWY). Light and electron microscopy were also performed. Anatomical and functional changes were present in the reexpanded lung after relief of pneumothorax. Both increased time of collapse and suction reexpansion tended to correlate with increased PEWV, decreased surfactant and arterial PO2, and increased A-aDO2.

Adult↗
PubMed1978

Bleomycin-induced diffuse interstitial pulmonary fibrosis in baboons.

Pulmonary fibrosis was induced in eight baboons with bleomycin; five untreated animals were controls. After 45-65 U/kg of bleomycin, lung volumes and diffusing capacity were reduced, and static lung pressure-volume curves were shifted to the right. Right middle lobes were resected at this time in five bleomycin-treated and two control animals. Compared to controls, right middle lobes from bleomycintreated animals had increased weight and contained increased amounts of total protein, collagen, elastin, and DNA; synthesis of collagen and noncollagen protein were also elevated. Occasional alveolar septae were edematous and infiltrated by mononuclear inflammatory cells; a slight increase in collagen was demonstrable histologically. Four of six treated animals died with extensive diffuse interstitial fibrosis after 95 U/kg of bleomycin. Biochemical analyses revealed significantly elevated lobar contents of dry weight, protein, elastin, and collagen. Two animals survived 95 U/kg of bleomycin and were terminated 6 mo after treatment. In these animals, physiologic studies were indicative of restrictive lung disease, but lung histology was nearly normal. Lung weight, total protein, and DNA had returned to control values, but collagen and elastin were increased in amount and concentration. Bleomycin induces an intense inflammatory response in the lung. During this inflammation, connective tissue proliferation occurs in concert with proliferation of other tissue components. Cessation of bleomycin treatment is followed by resolution of inflammation manifested by decreases in tissue mass, cellular content, and nonconnective tissue protein. Collagen and elastin deposited during inflammation are less successfully removed during resolution, leading to a stage characterized by increased concentrations of these proteins. A similar sequence of tissue alterations may occur in idiopathic diffuse interstitial fibrosis of man in response to various lung injuries.

Animals↗
PubMed1978

Pulmonary artery aneurysm.

Less than 200 cases of main pulmonary artery aneurysms have been reported and most came from autopsy series. The aneurysms may be associated with congenital cardiovascular lesions, syphilis, degenerative changes in the arterial wall and possibly trauma. Pulmonary artery aneurysm is a true entity which can occur with or without typical clinical findings. Physicians should pay more attention to the so-called "aneurysmal dilatation" or "idiopathic dilatation" of the pulmonary artery and obtain a correct diagnosis by angiography. Since pulmonary artery aneurysm carries a risk of rupturing, the operation should be considered as soon as the lesion is recognized. Few surgical interventions have been reported.

Adult↗
PubMed1977

Management of subclavian and innominate artery injuries.

Subclavian and innominate arterial injuries are life-threatening and require aggressive treatment. Physical findings, chest x-ray examinations, and a high index of suspicion led to expoloration in seventeen of twenty-two patients in this series, but the selective use of arteriography is helpful. Primary repair was accomplished in nineteen of the twenty-two patients. Wide proximal exposure proved to be accompanied by little morbidity with the reward of increasing survival to 95.5 per cent.

Adolescent↗