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Biomedical subjects

L R Golding

Publications and source records attributed to L R Golding.

At least 19 recordsLinked to original sources
PubMed1992

Experimental and clinical evaluation of a noninvasive reflectance pulse oximeter sensor.

The objective of this study was to evaluate a new reflectance pulse oximeter sensor. The prototype sensor consists of 8 light-emitting diode (LED) chips (4 at 665 nm and 4 at 820 nm) and a photodiode chip mounted on a single substrate. The 4 LED chips for each wavelength are spaced at 90-degree intervals around the substrate and at an equal radial distance from the photodiode chip. An optical barrier between the photodiode and LED chips prevents a direct coupling effect between them. Near-infrared LEDs (940 nm) in the sensor warm the tissue. The microthermocouple mounted on the sensor surface measures the temperature of the skin-sensor interface and maintains it at a present level by servoregulating the current in the 940-nm LEDs. An animal study and a clinical study were performed. In the animal study, 5 mongrel dogs (weight, 10-20 kg) were anesthetized, mechanically ventilated, and cannulated. In each animal, arterial oxygen saturation (SaO2) was measured continuously by a standard transmission oximeter probe placed on the dog's earlobe and a reflectance oximeter sensor placed on the dog's tongue. In the first phase of the experiment, signals from the reflectance sensor were recorded while the dog was immersed in ice water until its body temperature decreased to 30 degrees C. In the second phase, the animal's body temperature was normal, and the oxygen content of the ventilator was varied to alter the SaO2. In the clinical study, 18 critically ill patients were monitored perioperatively with the prototype reflectance sensor. The first phase of the study investigated the relationship between local skin temperature and the accuracy of oximeter readings with the reflectance sensor. Each measurement was taken at a high saturation level as a function of local skin temperature. The second phase of the study compared measurements of oxygen saturation by a reflectance oximeter (SpO2[r]) with those made by a co-oximeter (SaO2[IL]) and a standard transmission oximeter (SpO2[t]). Linear regression analysis was used to determine the degree of correlation between (1) the pulse amplitude and skin temperature; (2) SpO2(r) and SaO2(IL); and (3) SpO2(t) and SaO2(IL). Student's t test was used to determine the significance of each correlation. The mean and standard deviation of the differences were also computed. In the animal study, pulse amplitude levels increased concomitantly with skin temperature (at 665 nm, r = 0.9424; at 820 nm, r = 0.9834; p < 0.001) and SpO2(r) correlated well with SaO2(IL) (r = 0.982; SEE = 2.54%; p < 0.001).(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Pacemaker and defibrillator combination therapy for recurrent ventricular tachycardia.

The judicious use of antitachycardia pacemakers can enhance the benefits of automatic implantable cardioverter defibrillators in certain patients. Both devices were implanted in 10 highly selected patients with drug-refractory pace-terminable sustained ventricular tachycardia. During the observation period of 8 +/- 4.8 months, the automatic pacemakers detected 1,542 episodes of ventricular tachycardia and appropriately managed 1,373. The automatic implantable defibrillator was activated at least once in every patient; on two documented occasions, the defibrillator discharged because the automatic pacemaker accelerated the tachycardia. Concomitant antiarrhythmic drugs could be reduced but not withdrawn. With meticulous device programming and testing, the two systems in combination can work synergistically to manage malignant ventricular arrhythmias in carefully selected patients.

Aged↗
PubMed1988

Applicability of mitral valvuloplasty techniques in a North American population.

Records of 520 patients who underwent mitral valve operations were reviewed to determine the pathophysiology, etiology, anatomy of the valve lesion and use of valvuloplasty techniques. Pure mitral regurgitation, present in 269 patients (52%), was the most common lesion while rheumatic valvulitis, seen in 286 patients (55%), was the most common etiology. Degenerative lesions were found in 168 patients, 33% of the total and 63% of the pure mitral regurgitation group. Two-hundred seventy patients (52%) were treated with valvuloplasty techniques. The incidence of reconstructive procedures was determined for each of the various patient subsets. Overall hospital mortality was 5.6% in the series: 8.4% for mitral replacement compared with 3% for mitral valvuloplasty (p = 0.007). Among patients undergoing primary isolated mitral procedures, hospital mortality for replacement was 7.5% compared with 1.4% for valvuloplasty (p = 0.018). Mitral valvuloplasty seems to provide a therapeutic alternative applicable to the spectrum of mitral valve pathology seen in a North American population.

Female↗
PubMed1988

Cyclosporin-associated microfibrils in cardiac transplant patients.

Endomyocardial biopsies from 21 cyclosporin-treated cardiac transplant patients were studied at the ultrastructural level. Eight patients exhibited focal interstitial accumulation of filaments, which most commonly measured 8-10 nm in diameter (range 7-16 nm). The filaments were straight, hollow, and nonbranching. Filament accumulation was observed as early as 4 days posttransplant. No filament accumulation was observed in 17 donor endomyocardial biopsies obtained at the time of transplantation. The ultrastructure of the filaments was similar to that of amyloid fibrils. Stains for amyloid at the light microscopic level were uniformly negative, however. Until the exact nature of the filaments is determined, we propose that they be referred to as cyclosporin associated microfibrils.

Actin Cytoskeleton↗
PubMed1987

Reversibility of myocyte injury in moderate and severe acute rejection in cyclosporine-treated cardiac transplant patients.

Myocyte injury in acute cardiac transplant rejection was studied ultrastructurally in 45 patients. Mild myocyte injury consisted of increased glycogen granules and mitochondria, and condensation and streaming of myofilaments. More severe cell injury was characterized by clumping of Z-band material at the periphery of the cell and loss of sarcomeric units. Cell swelling was not seen, and intramitochondrial dense deposits (indicative of irreversible cell injury) were rarely seen. Restoration of normal myocyte ultrastructure occurred after treatment for rejection. Although the light microscopic appearance of moderate or severe acute rejection may suggest myocyte necrosis, this is rarely observed ultrastructurally. We conclude that the majority of cell injury in acute rejection is potentially reversible.

Biopsy↗
PubMed1986

Reoperations for valve surgery: perioperative mortality and determinants of risk for 1,000 patients, 1958-1984.

One thousand consecutive cardiac reoperations for valve surgery in 897 patients were reviewed to determine in-hospital mortality and indicators of risk. Subgroups based on the number of previous cardiac procedures and the valve or valves replaced or repaired at reoperation (aortic valve, mitral valve, tricuspid valve, or multiple valves and mortality [deaths/number of procedures (% mortality)]) for those subgroups are as follows: (Table: see text) Predictors of increased risk for a first aortic valve reoperation were advanced age (p = .0002), endocarditis (p = .0018), female sex (p = .014), impaired left ventricular function (p = .039), and number of coronary vessels obstructed by 70% or more (p = .055). For a first mitral valve reoperation, the predictors were advanced age (p less than .0001), preoperative shock or cardiac arrest (p = .01), previous aortic or tricuspid valve operations (p = .02), type of mitral valve procedure (risk for repair of periprosthetic leak was greater than mitral valve replacement which was greater than mitral valve-conserving operation [p = .05]), and impaired left ventricular function (p = .059). For a first multiple valve reoperation, the predictors were diabetes (p = .04) and ascites (p = .02), whereas patients undergoing mitral valve replacement and tricuspid valve operations were at decreased risk (p = .01). Comparison of second reoperations with first reoperations indicates risk increases for multiple operations (p = .01) but not for aortic or mitral valve procedures. Rereplacement of a prosthesis (p = .007), coronary bypass grafting at reoperation (p = .006), and advanced age (p = .06) increased the risk for second reoperations. Age is the most consistent predictor of risk for patients undergoing valve reoperations.

Aortic Valve↗
PubMed1986

Clinical temporary ventricular assist. Pathologic findings and their implications in a multi-institutional study of 41 patients.

Forty-one patients, distributed among four centers, had left (33 patients), right (five), or bilateral (three) temporary ventricular assistance with textured (24) or smooth (17) surfaced diaphragm pumps, during an evaluation supported by the National Institutes of Health. Cardiac failure had occurred in 39 postoperative patients (after aorta-coronary bypass [23], valve replacement [four], both [nine], or other [three]), with total cardiopulmonary bypass time mean 306 minutes (range 69 to 600). Two patients had cardiomyopathy. Death of 35 nonsurvivors was due to myocardial necrosis (14), hemorrhage (nine), cerebrovascular accidents (three), infection (three), and other (six). Mean duration of support in all patients was 62 hours. In 16 patients (40%) whose condition improved, cardiac assist duration was mean 127 hours (range 48 to 264), compared with mean 19 hours (range 1 to 120) in 25 who did not. Of 17 patients in whom duration of support exceeded 72 hours, 15 (88%) improved, 11 were weaned, and six survived long term. Tissue examination (in 33 patients) by biopsy at pump implantation or autopsy revealed coagulation or contraction band myocyte necrosis, with or without hemorrhage, in 26 patients; of these, 10 improved and six were long-term survivors. Pump-related complications (two) included pulmonary embolism, most likely related to a cannulation site thrombus, and an aortic cannulation site infection in one patient each. This study suggests that mechanical cardiac assist may be accomplished with a low complication rate; should not necessarily be denied to patients with existing necrosis, because myocardial necrosis does not preclude improvement or survival; and frequently leads to functional myocardial recovery if patients survive early noncardiac complications, often the result of long duration of cardiopulmonary bypass.

Adolescent↗
PubMed1985

Determinants of blood utilization during myocardial revascularization.

Blood transfusion during cardiac surgical procedures has steadily decreased, but little information is available regarding the factors that determine its necessity or amount. To determine the predictors of blood utilization during myocardial revascularization, 441 consecutive patients undergoing primary myocardial revascularization were studied. Forty-four patients (10%) received blood during hospitalization with a mean transfusion of 0.3 +/- 1.4 units per patient. Age, sex, weight, body surface area, preoperative hematocrit, blood volume, and red blood cell volume were examined univariately for trends. All demonstrated a statistically significant trend for both need and amount of transfusion (p less than 0.001). Neither number of grafts nor duration of cardiopulmonary bypass demonstrated statistically significant trends. All univariately significant factors were evaluated by multivariate logistic regression analysis. Red cell volume was the best predictor of the need for transfusion (p less than 0.001), followed by age. No other factors improved predictive capabilities. We conclude that preoperative red cell mass and age are the principal determinants of the need for and quantity of blood transfused during myocardial revascularization. Use of this information may greatly improve the efficiency of ordering blood before operation.

Adult↗
PubMed1985

Does mammary artery grafting increase surgical risk?

From 1980 through 1982, 7105 patients underwent primary isolated myocardial revascularization. Of these, 49.2% received only vein grafts and 50.2% received at least one internal mammary artery graft. The incidence of mammary artery grafting increased from 33.5% in 1980 to 67.1% in 1982. The operative mortality rate was 1.4% in the vein group and 0.2% in the mammary artery group (p less than .0001). A multivariate analysis identified six incremental risk factors for operative mortality. After adjusting for these risk factors, the use of vein grafts only was found to be an incremental risk factor (p less than .0001). In a subset of patients without major risk factors, there was no difference in the incidence of perioperative infarction, respiratory insufficiency, wound complication, stroke, use of intra-aortic balloon, reoperation for bleeding, or blood requirements. We conclude that internal mammary artery grafting is safe and is not associated with increased surgical morbidity or mortality.

Adult↗
PubMed1985

Myocardial revascularization: evolution of a surgical procedure.

Since its inception, myocardial revascularization has steadily evolved. The patient population is older with more extensive cardiac disease. Surgical mortality is currently 1% with a less than 1% perioperative myocardial infarction rate. The number of grafts done per patient has increased to more than three with 80% of the patients being completely revascularized. Ninety percent of the patients receive at least one internal mammary artery graft. With more complete revascularization and greater use of the internal mammary artery, the prospects for long-term survival and palliation have improved.

Adult↗
PubMed1985

Long-term follow-up of postcardiotomy patients with profound cardiogenic shock treated with ventricular assist devices.

Success of ventricular assist devices in patients with postcardiotomy shock has provided enough survivors to allow evaluation of the length and quality of life. Fifteen survivors from 28 to 68 years (mean 53) old from four centers were followed for 6 to 77 months (mean 35) after discharge from the hospital. Four patients suffered perioperative myocardial infarctions. In three patients, ventricular function was normal before surgery and remained so afterward. Of 12 patients with moderate or severely impaired ventricular function, five improved, five were unchanged, and two were worse. One patient died 6 months after surgery of cardiomyopathy. Seven patients are employed full-time and one works part-time. Five patients are retired but active and one is moderately disabled. NYHA functional class improved in the patients as a group: 13 were in classes III and IV before surgery and 13 were in classes I and II after surgery. Two patients had noncardiac partial disability. Survivors of ventricular assist device support for postcardiotomy shock have an excellent chance for high-quality life and the risk of crippling cardiac disability is small.

Adult↗
PubMed1985

Successful acute heart-lung transplantation after six hours preservation.

The lack of an appropriate and effective technique for prolonged heart-lung preservation has been one of the factors limiting the use of this therapeutic modality. Presently, the donor is transported to the transplant center, which is often an unacceptable burden to the donor's family. A reliable preservation technique that would allow long-distance procurement would markedly increase the use of heart-lung transplantation. Using a dog, a successful heart-lung transplantation was achieved following six hours of preservation of the graft. The experiment was terminated when the animal was able to maintain normal blood gases following extubation.

Animals↗
PubMed1984

Young adults with coronary atherosclerosis: 10 year results of surgical myocardial revascularization.

This study reviews data on 107 patients, aged 35 years or younger, who underwent surgical coronary revascularization from 1971 to 1975. Early clinical events included one operative death and five nonfatal perioperative myocardial infarctions. Late follow-up (mean interval after operation 115 months) demonstrated actuarial survival rates of 94% at 5 years and 85% at 10 years. Fifteen late deaths, 23 nonfatal myocardial infarctions, 13 reoperations and return of severe angina in 10 patients were considered late clinical events. Actuarial survival free of early or late clinical events was 77% at 5 years and 53% at 10 postoperative years. Testing of clinical, angiographic and operative variables for influence on survival and event-free survival showed that survival was decreased by multivessel disease and impaired left ventricular function; event-free survival was decreased by a family history of coronary disease and cigarette smoking. Both survival and event-free survival were decreased by diabetes and elevated serum cholesterol. Postoperative cardiac catheterization (64 patients, mean postoperative interval 47 months) demonstrated that mammary artery graft patency (25 of 27, 93%) exceeded vein graft patency (49 of 88, 56%, p less than 0.01). The atherogenic diatheses of young adults may compromise the operative result, whereas use of internal mammary artery grafts may enhance the palliation of bypass surgery.

Adult↗
PubMed1984

A simple method for extended heart-lung preservation by autoperfusion.

A modification of Robicsek's autoperfusing heart-lung preparation preserved normal structure in the canine lung for 8 hrs and in the heart for 12 hrs. Applicable to both heart and heart-lung transplantation, the system would permit a safe extension of preservation time limits.

Animals↗
PubMed1983

A strategy for cost containment in coronary surgery.

Patients with multivessel coronary atherosclerosis and stable angina pectoris were examined by outpatient testing and admitted to a staging area with their families on the morning of coronary bypass surgery. This experimental group was not hospitalized before surgery. Their hospital charges were compared with those of cohorts of coronary artery surgery patients from 1977 to 1981 who met the same entrance criteria. Length of stay in the hospital was reduced by two days. A 10% savings in hospital charges was realized in the 1981 experimental group as compared with the 1981 control group. A comparison of total hospital charges, adjusted for inflation, shows that 1981 experimental group patients paid 35% less for their hospital room, 45% less for their intensive care period, and 17% less in total charges than the 1977 control group. Interviews indicated that these patients with stable cardiac conditions preferred to stay with their families or friends before surgery.

Aged↗
PubMed1983

Coronary artery surgery in women compared with men: analyses of risks and long-term results.

A surgical experience with 2,445 consecutive women who underwent isolated bypass grafting was analyzed for comparison with 18,079 consecutive men. Severe or unstable angina occurred preoperatively in 60% of women and 45% of men (p less than 0.001). Despite less three vessel disease (44 versus 56%, p less than 0.001) and better left ventricular contraction (normal in 60% of women and 53% of men [p less than 0.001]), women had a higher operative mortality rate (2.9 versus 1.3%). When matched for age, severity of angina and extent of coronary atherosclerosis, women still had twice the operative mortality of men. In matched patients, body surface area was the strongest predictor of operative risk, even when the model was adjusted for gender. When the model was adjusted for body surface area, gender was not an important predictor of operative death. The smaller size of women, rather than their sex, appears to explain the difference in operative mortality. After a mean interval of 2 years, women had a lower overall graft patency rate (76.4%) than men (82.1%) (p less than 0.001). At 5 and 10 years postoperatively, a higher percent of men were angina-free. Yet, survival for women (90.6%) and for men (93.0%) at 5 years, and at 10 years (78.6 and 78.2%, respectively) was not dissimilar.

Adolescent↗