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Biomedical subjects

M D Hagen

Publications and source records attributed to M D Hagen.

14 recordsLinked to original sources

Decision analysis: a review.

Decision analysis has been used increasingly to investigate complex medical decision problems and technologies. Four steps comprise the conduct of a decision analysis: construction of a decision tree, assignment of values to probabilities and outcomes, averaging out and folding back, and sensitivity analysis. Personal computer software is available to facilitate these tasks. Relevant outcome measures, such as the declining exponential approximation of life expectancy, have improved analysts' ability to express results in clinically pertinent terms. Decision analysis is a useful tool for exploring the uncertain and often ambiguous clinical problems facing primary care providers.

Coronary Disease

Tripping over technology.

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Cholangiopancreatography, Endoscopic Retrograde

Human immunodeficiency virus infection in health care workers. A method for estimating individual occupational risk.

Physicians and other health care workers are concerned about their occupational risk of acquiring human immunodeficiency virus infection. We have developed an approach that can help health care workers estimate their cumulative risk of infection with human immunodeficiency virus. Illustrations are used to develop a score that reflects an individual's occupational exposures and social behavior. This score is then translated into the probability that the worker is infected.

AIDS Serodiagnosis

Group G streptococcal bacteremia in a chronically constipated adolescent.

A chronically constipated, mentally retarded male adolescent was admitted on two occasions with gastroenteritis symptoms and stool positive for group G Streptococcus. The first episode was also associated with group G streptococcal bacteremia. This case of group G streptococcal disease is unique in that the primary symptoms were those of gastroenteritis. In the context of chronic constipation in colonic distention, the case appears to support the hypothesis of Watsky et al that group G streptococcal bacteremia is promoted by processes which breach anatomic mucosal or epithelial infection barriers.

Adolescent

New methodology for the synthesis of 2'(3')-O-aminoacyl oligoribonucleotides related to the 3'-terminus of aa-tRNA.

A new synthetic approach to the title compounds is reported. It is based on the phosphotriester methodology and uses a unique combination of protecting groups (Fmoc and Ph for the aglycons; DMT, CPTr and Mthp for the carbohydrate hydroxy functions; 2-CIPh for the phosphodiester bonds; BPOC for amino acid). This enables selective deprotection of the blocked oligonucleotide intermediates in two steps (oximate and acid treatments) to yield the 2'(3')-O-aminoacyl oligoribonucleotides suitable for biochemical investigations.

Indicators and Reagents

A pocket calculator program for using Pozen's formula.

Pozen's formula has been shown to improve diagnostic accuracy in patients with acute chest pain. This paper describes a short program for the HP-41CV calculator which reliably calculates acute ischemic heart disease probabilities using Pozen's formula.

Computers

Aortic aneurysm in a 74-year-old man with coronary disease and obstructive lung disease: is double jeopardy enough?

A previous decision analysis examined a patient with severe CAD, diminished ventricular function, and an abdominal aortic aneurysm and also concluded that CABG followed by aneurysm repair was optimal. This patient, who had well-preserved cardiac function but severely compromised pulmonary status, stood to gain less from CABG than would a patient with more severe coronary disease, thus accounting for the "close-call" between the CABG-AAA and AAA only strategies. Nevertheless, the analysis did emphasize the benefit of aneurysm repair, whether done alone or after CABG. The analysis also highlighted the significant risk of aneurysm rupture the patient is exposed to while recovering from CABG surgery. The operative mortality risks of the two procedures are similar; thus, the patient's total operative risk is approximately doubled if he undergoes both procedures rather than aneurysm repair alone. The key question raised by the analysis is whether this double jeopardy is more than compensated by the degree to which prior CABG reduces both short-term cardiac risk at subsequent aneurysm repair and long-term cardiac mortality. For this patient, who had good cardiac function, the gains appeared sufficient to offset the interval risk of aneurysm rupture and the additional risk associated with a surgical procedures. THE REAL WORLD The patient indeed underwent and tolerated CABG, although he had a stormy prolonged postoperative course due to pulmonary failure. After discharge from the hospital, he declined readmission for repair of the aneurysm. We did not model that possibility, clearly an inadequacy in our tree. Some six months later, the patient was still alive and was, reluctantly, readmitted for aneurysmorrhaphy. At that time, however, his pulmonary function had deteriorated and both the anesthesiologist and the pulmonary consultant stated unequivocally that further surgery was now impossible. In retrospect, the expected utility of CABG without aneurysm repair (thus providing only a decrease in the long-term mortality risk from his CAD) would have been 1.95 (DEALE) or 2.06 (Markov) years. Sensitivity analysis revealed that, even if long-term cardiac risk were completely eliminated by CABG, immediate aneurysm repair would have been a better approach had the patient's physicians known he would be likely to refuse or not be a candidate for the second operation. In summary, although the patient's comorbidities did indeed place him at significant operative risk for either aneurysmorrhaphy alone or two sequential procedures, the benefits to be gained were shown to far outweigh the risks when compared with expectant observation.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged

A method for projecting ambulatory visits to a family practice center.

Family practice model centers serve multiple teaching, research, and patient care roles. Accurate projection of patient care demand should promote a center's efficiency. Clinic visit forecasts were performed for a university based family practice center using an exponential time series analytic model. The model provided reliable clinic projections for a one-year time horizon. The projections proved useful for administrative, educational, and academic governance purposes. Time series analysis is a useful and relatively easily implemented tool which can facilitate family practice center administration and support.

Ambulatory Care Facilities