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Biomedical subjects

D G Hill

Publications and source records attributed to D G Hill.

At least 19 recordsLinked to original sources

Single-versus multiple-dose antibiotics prophylaxis for cardiac surgery.

BACKGROUND: This study was carried out to determine if single-dose antimicrobial prophylaxis is sufficient for cardiac surgery. METHODS: The study was a prospective non-randomized trial of 353 consecutive patients undergoing cardiac surgery. Group A (n = 151) received 48 h of prophylaxis and Group B (n = 202) received a single dose. Cephazolin was used in all patients except those at high risk from methicillin-resistant Staphylococcus aureus (MRSA) who received teicoplanin and timentin. RESULTS: There was an overall in-hospital infection rate of 2.8%. There was no significant difference in rate or type of infection between the two groups. CONCLUSIONS: An in-hospital infection rate of 2.8% compares favourably with other reported series. Single-dose antimicrobial prophylaxis is as effective as a 48-h regimen. Targeting high-risk groups is effective.

Aged↗

Aortic dissection associated with Campylobacter aortitis.

Infective aortitis and associated mycotic aneurysms are uncommon clinical entities and most reported cases are associated with Salmonella species. We report successful surgical and medical treatment of a mycotic aneurysm of the aorta which presented as acute pericarditis and may have been caused by Camplyobacter jejuni.

Journal Article↗

Right aortic arch with aberrant left subclavian artery: aneurysmal dilatation causing symptomatic compression of the right main bronchus in an adult.

A 60-year-old woman presented with a cough, nocturnal stridor and dysphagia. Bronchoscopy showed tight compression of the right main bronchus. Digital subtraction angiography (DSA) and a computed tomographic (CT) scan showed the presence of a right-sided aortic arch with aberrant left subclavian artery. The distal right arch and proximal right-sided descending thoracic aorta were aneurysmal and were responsible for this compression. Surgical relief was accomplished by dividing the aberrant left subclavian artery and replacing the aneurysm with a vascular graft.

Aneurysm↗

An update on American College of Radiology-National Electrical Manufacturers Association standards activity.

The American College of Radiology-National Electrical Manufacturer's Association (ACR-NEMA) Standard was published 5 years ago. Implementations are just now becoming available in a form other than a prototype. Though this seems like a long interval between the initial work and results, the organization responsible for the standard, the ACR-NEMA Digital Imaging and Communications Standards Committee, has not been idle. Much of the progress which has been made is the result of cooperative work involving industry, the Committee and its Working Groups (WG), and the medical imaging user community. This paper will briefly review the history of the development of what is now a family of ACR-NEMA standards, describe the current activity of the WGs, and indicate in what directions the WGs are headed for both new and updated standards.

Electronics, Medical↗

The effects of prostacyclin (PGI2) on haematological and haemodynamic parameters, and lung histology in puppies undergoing cardiopulmonary bypass surgery with profound hypothermia.

Puppies 6-12 kg underwent cardiopulmonary bypass with profound hypothermia. Thirteen animals received 200 ng kg-1 min-1 of PGI2 during bypass whilst 11 control animals received equivalent volumes of glycine buffer (placebo) over a similar period. Results indicated preservation of platelets, leukocytes and fibrinogen levels, together with shortened activated partial thromboplastin times and fewer fibrinogen degradation products post-bypass in PGI2-treated animals. There was an initial fall in blood pressure and systemic vascular resistance in PGI2 treated animals, but pulmonary pressures and resistances, cardiac outputs, and heart rates showed no significant differences from controls. Higher and more satisfactory end of bypass and post-bypass blood pressure levels, together with a lesser fall-off in mean total pulmonary compliance, and shortened bypass times were achieved in treated animals. PGI2 appeared to afford some protection against lung damage as observed by histological studies. All beneficial effects appeared to be significantly greater amongst smaller animals. The results indicate possible benefits from the use of PGI2 in infant open heart surgery.

Animals↗

Arrhythmia prophylaxis after aorta-coronary bypass. The effect of minidose propranolol.

After aorta-coronary bypass grafting, 164 consecutive patients were randomized to receive propranolol 5 mg every 6 hours orally (n = 82) or to serve as control subjects (n = 82). All patients were receiving beta blockers preoperatively. There were no significant differences between the two groups. The incidence of sustained supraventricular (nonsinus) tachyarrhythmias was 23% in the control group and 9.8% in the treated group (p = 0.02). The incidence of ventricular arrhythmias was 15% in the control group and 2.4% in the treated group (p = 0.005). The overall difference in clinically important arrhythmias was 38% in the control group and 12.2% in the treated group (p = 0.0002). We conclude that low-dose oral propranolol in patients who were receiving beta blockers preoperatively is effective in reducing the incidence of clinically important arrhythmias occurring after aorta-coronary bypass grafting.

Aged↗

Congenital aneurysm of the left atrium: diagnosis and management.

A case of congenital aneurysm of the left atrial appendage is presented and previously reported cases are reviewed. The diagnosis can be strongly suspected with the combination of an unusually prominent left heart border in the chest X-ray and two-dimensional echocardiographic findings of a large echo-free space close to the left atrium. The site of communication must be defined accurately and cardiac catheterisation and angiocardiography should be performed. Once the diagnosis is confirmed, surgery is indicated even in the asymptomatic patient because of the risk of systemic embolism.

Child↗

Subacute cardiac rupture: a surgical emergency.

Three cases of subacute cardiac rupture following acute myocardial infarction are described. All three patients experienced sudden collapse during convalescence and following cardiopulmonary resuscitation were in cardiogenic shock, the shock being due to haemopericardium causing cardiac tamponade. Two of the patients who had electrocardiographic monitoring at the time of their collapse showed nodal bradycardia and were apnoeic and unconscious with no recordable blood pressure (electromechanical dissociation). The diagnosis was confirmed in all three patients by echocardiography which showed pericardial fluid. The patients were referred for urgent cardiac surgery (infarctectomy and Teflon patching) without further investigation. All three patients survived the emergency operation, but two died soon after surgery. The third patient is alive and well five months after the operation.

Cardiac Tamponade↗

Coronary surgery after recurrent myocardial infarction: progress of a trial comparing surgical with nonsurgical management for asymptomatic patients with advanced coronary disease.

A randomized trial of surgical vs nonsurgical management was carried out in men 60 years of age or younger who had recovered from a recurrent myocardial infarction. Of 205 patients considered, 100 had few or no symptoms and had coronary vessels favorable for bypass grafting; these patients fulfilled the trial conditions and were randomized (50 surgical and 50 nonsurgical). In 41 patients (elective nonsurgical group), randomization was not considered justifiable because of relatively unfavorable coronary anatomy or severe left ventricular dysfunction. Nineteen patients had elective surgery because of disabling angina despite full medical treatment or because of significant left main coronary stenosis. In 45 patients, coronary angiography was not undertaken because of medical contraindications or reluctance of the patient to enter the study. Actuarial survival curves (mean follow-up 4.5 years) show an annual mortality rate of 3-4% per year for all investigated patients, and no advantage for the randomized surgical over the randomized nonsurgical group. The results suggest that in the absence of disabling angina or left main coronary artery stenosis, coronary artery surgery need not be advised for survivors of recurrent infarctions who have severe coronary artery disease. Moreover, the prognosis for the group of patients not treated surgically appears to be better than has been previously described.

Adult↗

5,6,7,8-Tetrahydroguinolines. 4. Antiulcer and antisecretory activity of 5,6,7,8-tetrahydroquinolinenitriles and -thioamides.

A number of 5,6,7,8-tetrahydroquinoling-8-nitriles and -8-thioamides and related compounds have been found to be potent inhibitors of basal gastric secretion in the pylorus-ligated rat and to afford protection against gastric erosions induced in rats by cold-restraint stress. Molecular manipulation has proved useful in determining factors necessary for such activity and structure-activity relationships are discussed. It has been shown that the most necessary requirements for activity are a pyridine nitrogen with its available lone pair and a primary or secondary thioamide. Also desirable is a six-membered carbocyclic ring with relative freedom from steric hinderance around the 8 position.

Animals↗

5,6,7,8-Tetrahydroquinolines. 5. Antiulcer and antisecretory activity of 5,6,7,8-tetrahydroquinolinethioureas and related heterocycles.

A series of thioureas derived from 5,6,7,8-tetrahydroquinoline, 1,5-, 1,6-, and 1,8-naphthyridiness, pyrido[2,3-b]azepine, and 7-azaindoline has been prepared and tested for antisecretory activity in the pylorus-ligated rat and protective activity against gastric erosions caused by cold-restraint stress. The thioureas exhibit different structure-activity relationships from the corresponding 5,6,7,8-tetrahydroquinoline-8-thiocarboxamides and these relationships are discussed. The activity of the thioureas is less affected by structural differences than the corresponding thioamides although they probably have the same mode of action.

Animals↗

Corticosteroids and prevention of pulmonary damage following cardiopulmonary bypass in puppies.

A technique of inducing hypothermia using surface cooling and rewarming with a pump oxygenator has been applied clinically in infants with satisfactory results. Respiratory problems postoperatively, however, are reported to be among the complications contributing most to mortality and morbidity. Prednisolone sodium succinate (Solumedrol) has helped to obviate pulmonary damage in hemorrhagic and endotoxic shock and therefore may be effective in preventing pulmonary damage following hypothermia. This hypothesis was investigated in 12 mongrel puppies, 6 that had hypothermic cardiopulmonary bypass and circulatory arrest but were not given Solumedrol, and 6 that were treated preoperatively with Solumedrol. In lung biopsies taken immediately after bypass the pathological changes in both the group treated with steroids and the control group were similar. At six hours, however, lung biopsies from the control group showed further signs of progressive damage, while in the steroid-treated group there was a striking improvement with some lung biopsies showing a normal appearance. Thus, Solumedrol did not prevent initial lung damage, but the progressive and probably permanent changes were reduced.

Air Sacs↗

Prophylactic antibiotics in open heart surgery.

Two prophylactic antibiotic regimes were compared in 129 patients who had open heart surgery for mitral and/or aortic valve replacements at Guy's Hospital. The first group were prescribed cephalothin for five days beginning with premedication. The second group were prescribed the combination of cloxacillin and gentamicin for the same time. The incidence of minor infection was low. There was no statistical difference between the two antibiotic regimes. The major infections were due predominantly to Gram negative organisms and difficult to prevent by any prophylactic regime.

Adolescent↗

Protection from lung damage by blood filtration during deep hypothermia in puppies.

Ten puppies underwent deep hypothermia with surface cooling and bypass cooling. They were subjected to circulatory arrest for 30 minutes and then were rewarmed by means of bypass. There were 5 control puppies and 5 for which a Swank filter was placed in the arterial perfusion line. All puppies had some degree of lung damage, but it was more severe in those in which perfused blood was not filtered. The damage involved the lung vessels, interstitial tissue, and alveoli. Platelet-fibrin aggregates and margination and sequestration of leukocytes appeared to be important pathological findings. Apparently, the Swank blood filter protects the lung by removing leukocytes and damaged platelets from the circulation.

Animals↗