An economic assessment of pre-vaccination screening for hepatitis A and B

OBJECTIVE: The availability of a single vaccine active against hepatitis A and B may facilitate prevention of both infections, but complicates the question of whether to conduct pre-vaccination screening. The authors examined the cost-effectiveness of pre-vaccination screening for several populations: first-year college students, military recruits, travelers to hepatitis A-endemic areas, patients at sexually transmitted disease clinics, and prison inmates. METHODS: Three prevention protocols were examined: (1) screen and defer vaccination until serology results are known; (2) screen and begin vaccination immediately to avoid a missed vaccination opportunity; and (3) vaccinate without screening. Data describing pre-vaccination immunity, vaccine effectiveness, and prevention costs borne by the health system (i.e., serology, vaccine acquisition, and administration) were derived from published literature and U.S. government websites. Using spreadsheet models, the authors calculated the ratio of prevention costs to the number of vaccine protections conferred. RESULTS: The vaccinate without screening protocol was most cost-effective in nine of 10 analyses conducted under baseline assumptions, and in 69 of 80 sensitivity analyses. In each population considered, vaccinate without screening was less costly than and at least equally as effective as screen and begin vaccination. The screen and defer vaccination protocol would reduce costs in seven populations, but effectiveness would also be lower. CONCLUSIONS: Unless directed at vaccination candidates with the highest probability of immunity, pre-vaccination screening for hepatitis A and B immunity is not cost-effective. Balancing cost reduction with reduced effectiveness, screen and defer may be preferred for older travelers and prison inmates.     

Chronic thalamotomy increases pain-related behavior in rats

The thalamus has been traditionally considered as the 'chief organ' by which pain is perceived (Head H, Holmes G. Sensory disturbances from cerebral lesions. Brain 1911;34:102-254). However, several clinical and experimental observations led to a challenge of this traditional view. In this report, we demonstrate that chronic thalamic lesions, instead of producing hypoalgesia, increased pain reactivity in rats. Different groups of rats were subjected to either subtotal, lateral or medial thalamic lesions. Their reactions to nociceptive stimuli were then assessed for a period of 1-2 months. Rats in the different groups showed an increased reactivity to acute mechanical and thermal nociceptive stimuli and an increase in the pain scores of the formalin test. These results suggest an important role of the thalamus in pain modulation in addition to that of nociceptive transmission.     

Gamma-knife radiosurgery for trigeminal neuralgia

Gamma knife was installed at the PD Hinduja National Hospital and Medical Research Centre, Mumbai, India, in January 1997. In the first year of gamma-knife radiosurgery to January 1998, we treated 110 patients, of whom six had medically refractory trigeminal neuralgia. Seven treatments were administered to this group of six patients (one had bilateral neuralgia). This report evaluates the effectiveness of radiosurgery treatment in these patients. The median age of the patients was 56 years and there were five males and one female. Following Leksell stereotactic frame fixation, a magnetic resonance imaging scan was done in all. The Leksell gamma plan was used for planning. A radiosurgery dose of 70–80 Gy was delivered to the trigeminal root entry zone, 2–4 mm anterior to the junction of the pons and trigeminal nerve with a single 4 mm collimator helmet. Complete pain relief was achieved in four patients. Two had partial relief. No patient developed any radiosurgery related morbidity during the follow-up period of 5–16 months. Radiosurgery seems to be an effective approach for medically or surgically refractory trigeminal neuralgia.     

Behavioral indices of threat and challenge in Hispanic adolescents and hemodynamic responses to a speech stressor.

Behavioral ratings of performance and nervousness during a speech were used to divide participants (n=54) into threat and challenge groups. Comparisons on cardiac output, Heather index, heart rate, vascular resistance, and blood pressure reactivity indicated greater myocardial responses for the challenge group. This study extends the threat-challenge literature by employing behavioral definitions of constructs and examining a Hispanic adolescent sample.     

Expert system-controlled image display

Conventional computer-based medical expert systems deliver advice to physicians as written text. While such advice is useful, it has distinct limitations in a visually oriented discipline such as diagnostic radiology, in which decisions often depend on pattern recognition and appreciation of subtle morphologic features. The authors developed a prototype expert computer system, IMAGE/ICON, which displays groups of images sorted into a series of axes based on different ways in which they may be similar. They may share a common feature, group of features, causes, or clinical setting. IMAGE/ICON may display examples of morphologic variations of a dominant finding or a spectrum of abnormalities seen in an specific disease or group of diseases. The system also assembles a written analysis of key features of a case. Such a tool may be useful as a diagnostic aid or for continuing medical education. It is likely to have particular impact in the form of an intelligent radiologic workstation, as picture archiving and communication systems become available.     

Evaluation of a 20 years' experience of colo-anal anastomoses. Indications, results and pitfalls

Seventy nine anastomoses were performed over a 20 year period. Indications included 68 rectal adenocarcinomas and 11 benign lesions. There was no operative mortality. Anastomotic leak was the main cause of morbidity: 12 clinical (15%) and 4 radiological leaks. The 5-year actuarial disease-free survival was 70%, 7 local recurrences (10%) were observed; 6 were Dukes C and 1 Dukes B. Functional results were assessed in 61 patients. They were considered to be excellent in 35 (57%), good in 24 (39%) and bad in 2 (4%). Six failures were noted: 3 technical, 1 oncologic and 2 functional. Pitfalls of coloanal anastomosis are discussed.     

Acute pulmonary oedema following smoke inhalation

A case of acute pulmonary oedema after smoke inhalation from a chip pan fire is presented. The role of bronchial and pulmonary circulation in the development of pulmonary oedema after smoke inhalation is discussed. We stress the importance not only of observation after smoke inhalation, as the manifestation of pulmonary oedema may be delayed, but also of a baseline chest X-ray before admission for comparison.     

Costs and clinical outcomes of primary prophylaxis of variceal bleeding in patients with hepatic cirrhosis: a decision analytic model

OBJECTIVE: Current guidelines recommend upper endoscopic screening for patients with hepatic cirrhosis and primary prophylaxis with a nonselective beta-blocker for those with large varices. METHODS: However, only 25% of cirrhotics develop large varices. Thus, the aim of this study is to evaluate the most cost-effective approach for primary prophylaxis of variceal hemorrhage. RESULTS: Using a Markov model, we compared the costs and clinical outcomes of three strategies for primary prophylaxis of variceal bleeding. In the first strategy, patients were given a beta-blocker without undergoing upper endoscopy. In the second strategy, patients underwent upper endoscopic screening; those found to have large varices were treated with a beta-blocker. In the third strategy, no prophylaxis was used. Selected sensitivity analyses were performed to validate outcomes.Our results show screening prophylaxis was associated with a cost of $37,300 and 5.72 quality-adjusted life yr (QALYs). Universal prophylaxis was associated with a cost of $34,100 and 6.65 QALYs. The no prophylaxis strategy was associated with a cost of $36,600 and 4.84 QALYs. The incremental cost-effectiveness ratio was $800/QALY for the endoscopic strategy relative to the no prophylaxis strategy. Screening endoscopy was cost saving when the compliance, bleed risk without beta-blocker, and variceal bleed costs were increased, and when the discount rate, bleed risk on beta-blockers, and cost of upper endoscopy were decreased. In contrast, the universal prophylaxis strategy was persistently cost saving relative to the no prophylaxis strategy. In comparing the strategies, sensitivity analysis on the death rates from variceal hemorrhage did not alter outcomes. CONCLUSIONS: Our results provide economic and clinical support for primary prophylaxis of esophageal variceal bleeding in patients with hepatic cirrhosis. Universal prophylaxis with beta-blocker is preferred because it is consistently associated with the lowest costs and highest QALYs.