Variability in interpretation among B-readers in the U.S. Navy Asbestos Medical Surveillance Program.

U.S. Navy Asbestos Medical Surveillance Program B-reading reports were analyzed for variability in identifying pneumoconiosis in 278,944 chest radiographs done from 1990 to 2004 using commercial database and statistical software. Reported presence of pneumoconiosis by 33 B-readers ranged from 1.85 to 32.28%. The reported presence of parenchymal abnormalities ranged from 0.11 to 15.07%; increased profusion (to 1/0 or greater) of small parenchymal opacities ranged from 0.10 to 17.70%; presence of large opacities ranged from 0.00 to 0.67%; and presence of pleural abnormalities ranged from 1.08 to 23.93%. Ranges appear to be decreasing slightly as rates of abnormal findings are diminishing. Differences between U.S. East Coast, West Coast, and midcontinent were not statistically significant.

Changes in B-readings over time in the United States Navy Asbestos Medical Surveillance Program.

OBJECTIVE: To study the impact of variability among B-readers on clinical occupational medicine. METHODS: A total of 419,770 B-reading reports from February 1980 to May 2004 in the US Navy Asbestos Medical Surveillance Program were analyzed for changes in category from the previous B-reading on each individual worker. RESULTS: Over 7% of films were categorized as worse (ie, read as going from negative to positive), and over 6% were categorized as better. When profusion categories were reported as different from the previous reading (over 6% of the time), they were more frequently read as 2 or more minor categories worse or better. CONCLUSIONS: Changes from previous B-readings are common, and may have clinical and other implications, which are discussed. B-readings should not be used as the sole basis for determining the presence or absence of pneumoconiosis.

Navy Asbestos Medical Surveillance Program 1990-1999: demographic features and trends in abnormal radiographic findings.

A 10-year cross-sectional analysis was conducted for 233,353 radiographic examinations performed as part of the Navy Asbestos Medical Surveillance Program. Demographic and temporal trends in abnormal radiographs were assessed during this analysis. Abnormal radiograph prevalence increased significantly with age, and abnormal radiographs were nearly 30 times more likely to occur among participants 60 to 69 years of age, compared with participants < 20 years of age (odds ratio, 27.57; 95% confidence interval, 14.75-51.53). Men were 5 times more likely than women to have an abnormal radiograph (odds ratio, 5.84; 95% confidence interval, 5.02-6.80); after controlling for differences in age, this gender association remained significant only for participants > 30 years of age. The proportion of abnormal radiographs decreased significantly over the study period [chi2 (df = 1) test for trend, chi2 = 198.7, p < 0.0001], although the cohort mean age increased. Despite aging of the Asbestos Medical Surveillance Program population, the overall prevalence of radiographic abnormalities is declining; future studies should examine the reasons for this observation.

Trends in pleural radiographic findings in the Navy Asbestos Medical Surveillance Program (1990-1999).

The U.S. Navy Asbestos Medical Surveillance Program is a comprehensive effort to decrease exposure to asbestos, a known health hazard. This study was part of a programmatic review of the Asbestos Medical Surveillance Program database, which included 233,353 radiographic examinations from 1990 to 1999. The initial review focused on incidental findings recorded by B-readers for 23,460 radiographs. Abnormalities reported included bullae (0.68%), cancer (0.56%), cardiac size/ shape abnormalities (1.36%), emphysema (0.74%), subpleural fat (2.62%), fractured ribs (1.24%), hilar adenopathy (0.13%), ill-defined diaphragm (0.46%), ill-defined heart border (0.29%), Kerley lines (0.06%), pleural thickening (2.35%), and tuberculosis (0.27%). The rates by age cohort for pleural abnormalities decreased significantly (30-39 years, chi2 for trend = 23.49, df = 1; 40-49 years, chi2 for trend = 176.21; 50-59 years, chi2 for trend = 401.87), but findings were not significantly different for those > or =60 years of age. This suggests that sequential age cohorts in the program are developing fewer pleural abnormalities; pleural abnormalities have historically been associated with asbestos exposure.

Lower-Dose Mepivacaine Plus Fentanyl May Improve Spinal Anesthesia for Knee Arthroscopy.

BACKGROUND: Previous work indicates that 30 mg isobaric mepivacaine 1.5% plus 10 µg fentanyl produces reliable anesthesia for knee arthroscopy with a more rapid recovery profile than 45 mg mepivacaine. QUESTIONS/PURPOSES: This randomized controlled trial compared plain mepivacaine to three reduced doses of mepivacaine with 10 µg fentanyl for spinal anesthesia. METHODS: Following written informed consent, subjects undergoing outpatient knee arthroscopy were prospectively randomized into one of four groups: mepivacaine 37.5 mg (M37.5); mepivacaine 30 mg plus fentanyl 10 µg (M30/F10); mepivacaine 27 mg plus fentanyl 10 µg (M27/F10); and mepivacaine 24 mg plus fentanyl 10 µg (M24/F10). The spinal was evaluated by the blinded anesthetist and surgeon. In the post-anesthesia care unit, sensory and motor block resolution was assessed. Subjects rated their satisfaction with the overall experience. RESULTS: Group M30/F10 (n = 6) had two "fair" anesthetics, and group M27/F10 (n = 10) had one "fair" and one "inadequate" anesthetic. Both groups were eliminated from further enrollment per study protocol. The recovery profiles showed little difference between groups M37.5 and M30/F10, except for motor block resolution (median (25th percentile, 75th percentile): 171 (135, 195) and 128 (120, 135), respectively). Groups M27/F10 and M24/F10 demonstrated recovery profiles that were faster than group M37.5. Patient satisfaction was 10/10 for all groups. CONCLUSIONS: Adding fentanyl 10 µg to a lower dose of mepivacaine 1.5% can lead to quicker recovery profiles. However, this advantage of a quicker recovery must be weighed against the likelihood of an incomplete anesthetic.

U.S. Navy and Marine Corps Hearing Conservation Program, 1995-1999: mean hearing thresholds for enlisted personnel by gender and age groups.

This study presents mean hearing thresholds from a cross-sectional study of 68,632 monitoring audiograms submitted to the Navy Environmental Health Center for 1995 to 1999. Records included U.S. Navy and U.S. Marine Corps enlisted personnel (Navy men = 51,643; Navy women = 4,184; Marine Corps men = 12,251: Marine Corps women = 554). Mean hearing thresholds were calculated for age groups (17-24, 25-29, 30-34, 35-39, 40-44, 45-49, and 50 years and older), gender (male/female), and service (Navy/Marine Corps). Although hearing thresholds worsened with increasing age, as expected, Navy and Marine Corps men have worse levels than Occupational Safety and Health Administration age-corrected values throughout most of their careers, whereas women were closer to the Occupational Safety and Health Administration values. Hearing thresholds in the Navy have not improved appreciably from historical reports. Threshold variability, as revealed by standard deviations, increased with age and paralleled threshold levels. This epidemiological information suggests that hearing conservation continues to be an important force health protection issue.

Decreasing the local anesthetic volume from 20 to 10 mL for ultrasound-guided interscalene block at the cricoid level does not reduce the incidence of hemidiaphragmatic paresis.

BACKGROUND AND OBJECTIVES: This prospective, randomized, double blind study was designed to determine whether reduction in volume from 20 to 10 mL of ropivacaine 0.5% for ultrasound-guided interscalene block might decrease the incidence of diaphragmatic paresis and preserve pulmonary function. METHOD: Thirty patients scheduled for arthroscopic shoulder surgery were randomized to receive either 10 or 20 mL of ropivacaine 0.5% for interscalene block at the level of the cricoid cartilage. General anesthesia was administered for surgery, and the surgeon infiltrated lidocaine at the port sites. Hemidiaphragmatic excursion and pulmonary function tests were measured before block, 15 mins after block, and at the time of discharge from recovery room. Onset and duration of sensory dermatomal spread, motor block, pain scores, and analgesic consumption were recorded. RESULTS: Hemidiaphragmatic paresis occurred 15 mins after block performance in 14 of 15 patients in each group. At postanesthesia care unit discharge, 13 of 15 patients in each group continued to demonstrate hemidiaphragmatic paresis. Significant reduction of spirometric values(forced vital capacity, forced expiratory volume at 1 sec, and peak expiratory flow) occurred to a similar degree in both groups after block.Sensory dermatomal spread, motor block, pain scores, and analgesic consumption were not significantly different between groups. CONCLUSIONS: Decreasing the volume for interscalene block from 20 to 10 mL did not reduce the incidence of hemidiaphragmatic paresis or impairment in pulmonary function, which persisted at discharge from recovery room. No significant differences in quality or duration of analgesia were observed.