Periosteal changes secondary to prostaglandin administration

underestimated, as illustrated by Dr. O'Sullivan's report and our experience. Mild symptoms and objective evidence for psychomotor impairment have been reported at COHb concentrations <10%? Smokers commonly have COHb concentrations in the 5% to 10% range, and may be especially vulnerable to undetected indoor sources of carbon monoxide. Finally, carbon monoxide exposure is potentially lethal and, once suspected, can be easily verified by measuring COHb in a venous blood sample. Jose Velasquez Rojas, M.D. Anthony L. Mansell, M.D. Department o f Pediatrics Pediatric Pulmonary Division College o f Physicians & Surgeons o f Columbia University 630 W. 168th St. New York, N Y 10032 REFERENCES 1. Ayres SM, Muller HS, et al: Systemic and myocardial hemodynamic responses to relatively small concentrations of carboxyhemoglobin. Arch Environ Health 18:699, 1969. 2. Morandi M, Eisenbud M: Carbon monoxide exposure in New York City: A historical overview. Bull NY Acad Med 56:817, 1980. 3. U.S. Environmental Protection Agency: A study of indoor air quality. Research Triangle Park, NC, 1974, No. 650/474-042. 4. U.S. Environmental Protection Agency: Indoor air pollution in the residential environment, vol. 1. Data collection: Analysis and interpretation. Research Triangle Park, NC, 1978, HUD-US, EDA 600/7-78-229a. 5. National Academy of Sciences: Carbon monoxide. Washington, DC, 1977, The Academy.