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Biomedical subjects

E B Larson

Publications and source records attributed to E B Larson.

At least 217 records · Page 12Linked to original sources
PubMed1984

Should single-phase radionuclide bone imaging be used in suspected osteomyelitis?

The records of 69 patients who had 86 delayed, static radionuclide bone images for suspected osteomyelitis were studied to determine the effects of this procedure on diagnosis and treatment. Sensitivity, specificity, and positive predictive value were lower than reported in several other studies. When osteomyelitis was unlikely, imaging was either negative or falsely positive and rarely affected treatment. In 46 cases where osteomyelitis was more likely, imaging potentially changed therapy in 19 but was unhelpful or misleading in 15. One third of the interpretations were "equivocal" and these were incorrect four times more often than "definite" readings. Two false-positive images led to unnecessary surgeries, and one patient with negative images died with unrecognized osteomyelitis. Static-phase images with "definite" interpretations, particularly when negative, are specific, but "equivocal" studies may lead to diagnostic and therapeutic errors. When osteomyelitis is improbable, imaging rarely changes diagnosis or therapy.

Adolescent↗
PubMed1984

Adult Still's disease. Evolution of a clinical syndrome and diagnosis, treatment, and follow-up of 17 patients.

Adult Still's Disease (SD) has evolved into a well-characterized nosologic entity. This categorization allows physicians to place a unifying label on the rare, puzzling patient who presents with a systemic illness characterized by high spiking fever of unknown cause associated with intense arthralgias or arthritis, an evanescent erythematous macular or maculopapular rash, and other less constant features of systemic illness including lymphadenopathy, hepatosplenomegaly, sore throat, leukocytosis, anemia and elevated concentration of hepatic enzymes. The diagnosis of Adult SD is syndromic, based solely on compatible clinical findings; serologic or other diagnostic tests do not aid in diagnosis. The diagnostic problem presented by these patients with such severe systemic illness and the insecurities inherent in diagnosis based solely on clinical features make the availability of the diagnosis, Adult SD, useful in patient care. The cause of Adult SD is unknown. Some have speculated that the disease has features of non-necrotizing immune complex vasculitis. Rubella infection has been reported to be associated with Adult SD, but no clear-cut etiologic relationship has been established. Neither rubella infection nor any other potential antigen has been identified consistently in association with the disease. Management of patients with the disease depends on the correct diagnosis. Diagnosis should include recognition of the syndrome as well as exclude other possible diseases. Control of systemic manifestations may require unusually high doses of aspirin, indomethacin or other non-steroidal anti-inflammatory drugs, prednisone or combinations of these drugs. Some adults appear to require both high-dose prednisone and indomethacin to control disease manifestations. Fortunately, systemic attacks are usually episodic; steroid toxicity can be minimized by use of alternate day doses and attempts to discontinue steroids between episodes. The current series and other reports of long-term follow-up indicate that Adult SD may be more disabling than was originally reported. At least three patterns of recurrences occur: 1) systemic attacks with or without arthritis, 2) pauciarticular disease, and 3) disabling deforming chronic arthritis, which may require surgery and long-term anti-inflammatory, gold, or cytotoxic therapy.

Adolescent↗
PubMed1983

Effect of acetazolamide on normoxic and hypoxic exercise in humans at sea level.

Acetazolamide (A) is a potent inhibitor of carbonic anhydrase. It has been shown to be efficacious in preventing acute mountain sickness as well as decreasing the O2 desaturation that occurs during sleep in individuals with chronic mountain sickness who live at altitude. Very little data, however, are available about its effect on exercise. We studied six healthy males in a double-blind cross-over design using acetazolamide and placebo (P) during normoxic and hypoxic (fractional inspired O2 = 0.118) progressive work exercise to exhaustion on a bicycle ergometer. A metabolic acidosis was documented in all subjects on A (P less than 0.045). Before exercise, subjects on A had 2.0 and 3.5 l/min increase in minute ventilation (VE) during normoxia (P = not significant) and hypoxia (P less than 0.005), respectively, and a 2.2% increase in arterialized O2 hemoglobin saturation (SaO2) during hypoxia. During normoxic and hypoxic exercise, VE/kpm and SaO2/kpm were significantly higher while the respiratory exchange ratio (R) was significantly lower on A. These effects were greater on hypoxia. During normoxia, maximal O2 consumption (1/min) was lower on A [3.1 +/- 0.4 (A) vs. 3.8 +/- 0.2 (P), P less than 0.025] and higher during hypoxia on A[2.6 +/- 0.7 (A) vs. 2.4 +/- 0.1 (P), P less than 0.05]. The increase in exercise VE on A may result in an increased alveolar and subsequent arterial O2 tension which may be important for exercise at altitude. Carbonic anhydrase inhibition may also affect CO2 transport in the lung, which may explain the lower R.

Acetazolamide↗
PubMed1983

Acute mountain sickness, antacids, and ventilation during rapid, active ascent of Mount Rainier.

A double-blind randomized study of 45 climbers on Mt. Rainier was conducted to test the effectiveness of antacids in preventing acute mountain sickness. All 45 climbed to 3353 m, and 31 continued to the summit. Ten climbers listed acute mountain sickness as the reason for not attaining the summit. Of symptoms monitored throughout the climb, neither headache, nausea, dizziness, pounding heart, nor shortness of breath differed in severity between antacid-treated and placebo-treated groups. In both groups vital capacity decreased significantly with ascent (p less than 0.05), while peak flow (p less than 0.005) and minute ventilation (p less than 0.001) increased significantly. The 7 climbers with the most severe AMS symptom scores above 4000 m had significantly lower peak flow at sea level prior to ascent compared with the other 25 climbers who completed sea level tests (p less than 0.005). The results of this study fail to document efficacy for antacid use for the prevention of acute mountain sickness.

Adult↗
PubMed1983

Inadequate medical order writing. A source of confusion and increased costs.

Audits of medication and intravenous fluid orders and of return to the pharmacy of unused intravenous solutions were conducted in 1980 at a university teaching hospital in response to a prevailing impression among pharmacists that physicians' orders were often written in an incomplete, nonstandardized fashion and that intravenous fluid wastage was common. A disturbing number of order were incomplete and judged to be ambiguous. Less than 25% of orders for intravenously given solutions contained adequate instructions for subsequent administration of fluids. Intravenous fluid return amounted to an estimated loss of $137,695 per year in wasted material and labor. The results of the audits were disseminated among the staff. In addition, the pharmacy changed its operations to detect more quickly and correct the problems caused by ambiguous orders. Later studies showed a reduction in the return of unused intravenous fluids and some improvement in order writing. Inadequate and ambiguous orders were still judged to be a problem, however, especially intravenous fluid orders that omitted instructions for subsequent fluid requirements and "open-ended" intravenous fluid orders. Such orders were eight times more likely to be associated with return of unused intravenous fluids than orders with adequate instructions for giving fluids subsequently.

Drug Prescriptions↗
PubMed1982

Clinical use of radionuclide bone imaging in a university medical center.

To assess the diagnostic utility of radionuclide bone imaging, we reviewed all examinations performed during a two-year period in a university medical center. The indication(s) for each bone image and its interpretation were compared by reviewing requisition forms and medical records. Thirty-nine percent of 988 studies demonstrated relevant abnormalities. Yields of pertinent positive findings were greatest in patients with cancers of the breast (40%) and prostate (38%) and lowest in women with uterine cancer (15%), patients with previously normal bone images, and individuals with suspected but unconfirmed malignancy. Incidental findings, unrelated to the indication for imaging, occurred frequently (up to 41% of cases). We did not find a sizable number of negative studies that could readily be labeled as unnecessary, suggesting that bone imaging to generally a useful procedure as applied by physicians in this setting.

Academic Medical Centers↗
PubMed1982

Acute mountain sickness and acetazolamide. Clinical efficacy and effect on ventilation.

Sixty-four climbers participated in a randomized clinical trial of acetazolamide prophylaxis for acute mountain sickness (AMS) during rapid, active ascent of MT Rainier. Twenty-nine (93.6%) of 31 climbers receiving acetazolamide and 25 (75.8%) of 33 receiving placebo attained the summit. Time spent ascending from sea level to the summit (4,394 m) averaged 33.5 hours (range, 23 to 48 hours). On the summit AMS was less common in climbers receiving acetazolamide, and they experienced less headache, nausea, drowsiness, shortness of breath, and dizziness and a greater sense of satisfaction and psychological well-being. Minute ventilation on the summit was significantly greater in subjects taking acetazolamide (24.9 +/- 2.0 L/min compared with 16.9 +/- 3.8 L/min). Expired vital capacity was also greater on the summit in the acetazolamide group (6.9 +/- 0.4 L compared with 5.8 +/- 0.4 L). We conclude that acetazolamide is effective in the prophylaxis of AMS for climbers attempting rapid, active ascent. Increased ventilation at altitude, producing an increased alveolar oxygen tension, may be related to the observed amelioration of symptoms.

Acetazolamide↗
PubMed1982

Do postcard reminders improve influenza compliance? A prospective trial of different postcard "cues".

A randomized trial of various postcard reminder "cues" was performed to improve understanding of health-related behavior and to find better strategies for improving influenza vaccination compliance. Data were gathered on 283 high-risk patients (92 per cent response rate) who received: 1) a "neutral" cue simply announcing the availability of vaccine; 2) a "Health-Belief-Model" card written to take advantage of the association between certain health beliefs and vaccination behavior; 3) a "personal" card signed by the patient's physician; or 4) no postcard. The highest rate of vaccination occurred among recipients of the Health-Belief-Model postcard (51.5 per cent vs. 20.2 per cent for control, p less than 0.001). Linear logistic regression analysis found that age, prior vaccination history and experimental group had a significant effect on likelihood of being vaccinated. After adjusting for age and prior vaccination experience, the vaccination rate was found to be significantly higher for persons receiving the Health-Belief-Model postcard compared with persons receiving no postcard or a neutral postcard. We conclude that reminder postcards emphasizing elements of the health belief model may help increase vaccination rates.

Aged↗
PubMed1981

Computed tomography in patients with psychiatric illnesses: advantage of a "rule-in" approach.

Computed tomography (CT) is used commonly to "rule-out" disease. In 123 consecutive patients with psychiatric diseases in three institutions, 105 CT scans (85.4%) interpreted as normal or normal except for atrophy did not influence management, only reassured clinicians and patients. Incidental and false positive findings were more numerous than true positive findings. All six true positive findings occurred in patients with focal findings on neurologic examination; four led to management changes. The lower 954% confidence limit of the cost of case finding by CT only was estimated to be $2931 for all patients; $603 for patients with focal findings; and at least $7083 for patients without focal findings. Computed tomography is a sensitive diagnostic method that may detect more false and incidental positive findings when used somewhat unselectively to "rule-out" disease. In these patients, a examination suggesting structural intracranial abnormalities would have been less expensive and more effective.

Adolescent↗