Reducing motor-vehicle collisions, costs, and fatalities by treating obstructive sleep apnea syndrome

STUDY OBJECTIVES: Drivers suffering from obstructive sleep apnea syndrome (OSAS) have an increased risk for being involved in motor-vehicle collisions. This study estimates, for the first time, the annual OSAS-related collisions, costs, and fatalities in the United States and performs a cost-benefit analysis of treating drivers suffering from OSAS with continuous positive airway pressure (CPAP). DESIGN: The MEDLINE-PubMed database (1980 to 2003) was searched for information on OSAS. A meta-analysis was performed of studies investigating the relationship between collisions and OSAS. Data from the National Safety Council were used to estimate OSAS-related collisions, costs, and fatalities and their reduction with treatment. Next, the annual cost of treating OSAS with CPAP was calculated. Finally, multiple 1-way sensitivity analyses were performed. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: More than 800,000 drivers were involved in OSAS-related motor-vehicle collisions in the year 2000. These collisions cost 15.9 billion dollars and 1,400 lives in the year 2000. In the United States, treating all drivers suffering from OSAS with CPAP would cost 3.18 billion dollars, save 11.1 billion dollars in collision costs, and save 980 lives annually. CONCLUSION: Annually, a small but significant portion of motor-vehicle collisions, costs, and deaths are related to OSAS. With CPAP treatment, most of these collisions, costs, and deaths can be prevented. Treatment of OSAS benefits both the patient and the public.     

Measurement of skin stretch via light reflection

A noninvasive technique for measuring the stretch of skin is described. The technique utilizes changes in the reflectivity of polarized light intensity as a monitor of skin stretch. Measurements of in vitro pigskin and in vivo human skin show that the reflectivity of polarized light intensity increases linearly with stretch. The changes in diffusive reflectivity properties of skin result from the alterations that take place in the roughness across the thickness of the skin layers due to stretch. Conceptually, as the roughness of a layer decreases with stretch, a smoother reflecting media is produced, resulting in a proportional increase in the specular reflection. Results can be easily extended to a real-time stretch analysis of large tissue areas that would be applicable for mapping the stretch of skin.     

Myelopoiesis in immunologically classified subgroups of childhood acute lymphocytic leukemia

Soft agar culture studies of 43 immunologically characterized patients with childhood acute lymphocytic leukemia (ALL) are presented. The immunologic subsets studied include “null”-cell, pre-B-cell, and T-cell leukemias. Abnormal myelopoiesis, including high peripheral blood and low marrow, colony-forming cell numbers, low colony-stimulating activity, and normal maturation of colony-forming cells in vitro was noted in each group as previously described for immunologically uncharacterized ALL. We conclude that immunologic subsets of childhood lymphoblastic leukemia cause similar abnormalities of myelopoiesis. Lack of differences in growth characteristics among immunologic subsets of ALL make it impossible to use this tissue culture technique in sub-classification of these leukemic disorders.     

Interobserver variation in the interpretation of abdominal radiographs

A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.     

Pneumothorax following transbronchial biopsy. Low diagnostic yield with routine chest roentgenograms

A chest roentgenogram is commonly obtained after a transbronchial biopsy to exclude a pneumothorax. We hypothesized that these routine chest roentgenograms rarely demonstrate a pneumothorax in patients who have neither symptoms nor fluoroscopic findings of lung collapse. To test this hypothesis, we studied 305 consecutive patients undergoing bronchoscopy with fluoroscopically guided TBB. No patient without symptoms and fluoroscopic findings suggesting lung collapse had a pneumothorax demonstrated on the post-biopsy chest roentgenogram. At the University of Virginia, routine chest roentgenograms failed to demonstrate a single unsuspected pneumothorax among all patients undergoing TBB during a period of nearly six years. Given this low incidence of unsuspected pneumothorax, we conclude that routine chest roentgenograms have a low diagnostic yield and may not be necessary in all patients after fluoroscopically guided TBB.