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Biomedical subjects

R Cohan

Publications and source records attributed to R Cohan.

6 recordsLinked to original sources

Dynamic, incremental computed tomography using a high heat capacity tube, solid-state detector, and automated injector. Potential in body imaging.

Using a new graphite tube, a prototype solid scintillating detector, and an automated injector, improvements were made in body computed tomography image quality. First, more scans with shorter interscan delay could be obtained with the improved tube. Second, liver image quality was improved with the use of higher techniques and a more consistent contrast bolus delivery with a mechanical injector. Last, body surveys were improved because the higher heat capacity tube provided the ability to rapidly scan and examine an entire region during the injection of contrast.

Automation↗

Complications of percutaneous nephrostolithotomy.

In 224 patients, renal stones were removed from the urinary tract using either direct extraction with a basket or forceps (59 patients), ultrasonic lithotripsy (164 patients), or infusion chemotherapy (one patient). Residual stone fragments were present more frequently in patients treated with ultrasonic lithotripsy (27%) than with direct extraction (5%). Other complications included hemorrhage (eight patients), catheter dislodgement (four patients), large amounts of urine extravasation (three patients), glycine ascites (three patients), infection (two patients), pneumothorax (one patient), and a prolonged ileus (one patient). More complications occurred among the first 50 patients than the last 50 patients, even though more difficult cases, including patients with staghorn calculi, were accepted during the latter period. Although a learning curve exists, complications can be minimized by attempting to treat more favorable cases during the initial experience.

Extravasation of Diagnostic and Therapeutic Materi↗

Suppression of histamine-induced pruritus by three antihistaminic drugs.

A double-blind crossover study of inhibition of histamine-induced pruritus by three commonly prescribed antihistamines was conducted on 28 normal subjects. Drugs used included diphenhydramine HCl (Benadryl), cyproheptadine (Periactin), hydroxyzine HCl (Atarax), and a lactose placebo in identical capsules. Intradermal histamine dose-response thresholds of pruritus were obtained before and after pretreatment with the three antihistamines and placebo in each subject. Analysis of data revealed a fivefold increase above baseline of the histamine dose required to produce pruritus following both cyproheptadine and placebo. This compared to a tenfold increase following diphenhydramine and a 750-fold increase following hydroxyzine HCl. The most common side effect was drowsiness, which occurred with all three drugs.

Adolescent↗

Mobile radiography CQI: an inter-national study.

Mobile or bedside radiography has been and is a staple diagnostic and follow-up tool used readily by the many medical disciplines, such as cardiology, surgery, orthopedics, pediatrics, neonatology, etc. Ironically, in the past a student or the least qualified technologist was sent to perform the bedside exam. Moreover, it was almost expected that poor but acceptable film quality would result or that repeat films were almost always to be taken. Inefficiency with respect to quality of exam, the time the exam takes, or film repeats can be costly. The price of inefficiency is the cost involved in doing things incorrectly or not in the most efficient manner, i.e., incurring inefficiencies instead of operating in an ideal manner. The purpose of this study was to compare the total cost of inefficiently organized, scheduled and performed mobile radiography at three large teaching hospitals in various locations and of diverse patient loads, as a means of determining how best to increase utilization and performance. The study was performed at the 489-bed New England Deaconess Hospital (NEDH), the 644-bed Sentara Norfolk General Hospital (SNGH), and the 1500-bed Rheinische Westfalische Technische Hochschule (RWTH) in Aachen, Germany. Similar standardized study methods were utilized at all three institutions where extended observation of mobile utilization, areas of inefficiency, time wasted per episode and number of episodes per time period were determined. Data were loggedin at three standardized time periods, summated, and then multiplied by technologist hourly pay rate. This sum was extrapolated over 52 weeks to give the total annual cost of inefficiently organized mobile radiography. For NEDH the cost of total inefficiency was $75,453, for SNGH $49,586, while for RWTH it was $9,519. Eighteen areas of inefficiency were identified and grouped, such as lack of spatial cohesiveness and lack of communication leading to film duplication, etc. While inefficiencies in the delivery of hospital based health care are well known, this study attempts to quantify and determine a dollar value for each process found as inefficient. Key inefficiencies were found to be common at large hospitals no matter whether in the United States or Europe. These impairments are responsible for a disproportionate share of overall inefficiency, and their elimination (achievable by simple solutions) would result in drastic cost reductions (ranging from 40-75% at the institutions studied). Thus this study is important in view of spiralling costs, as it is a key component of total quality management (TQM) in radiology and a continuous quality improvement (CQI) tool for mobile radiology specifically.

Efficiency, Organizational↗