['AUTHOR:', 'Bradley', 'J.', 'Ingebrethsen', 'DEPARTMENT:', 'Product', 'Evaluation', 'DIVISION:', 'Product', 'Applications', 'R&DM,', '1995,', 'No.', 'PROMEM', '95-0001', 'PAGES:', '62', 'PROGRAM:', 'Reduced', 'Controversial', 'Compounds', 'DATE:', '27', 'June,', '1995', 'PREVIOUS', 'REPORTS:', 'none', 'A', 'NUMERICAL', 'MODEL', 'OF', 'CARBOXYHEMOGLOBIN', 'CONCENTRATION', 'DURING', 'SMOKING', 'OBJECTIVE:', 'To', 'develop', 'an', 'improved', 'numerical', 'mode!', 'of', 'carboxyhemoglobin', '(COHb)', 'formation', 'and', 'clearance', 'that', 'simulates', 'the', 'smoking', 'associated', 'transients', 'of', 'puffing,', 'respiration,', 'and', 'blood', 'flow', 'more', 'accurately', 'than', 'available', 'averaging', 'models.', 'To', 'provide', 'a', 'theoretical', 'basis', 'for', 'the', 'analysis', 'and', 'interpretation', 'of', 'an', 'experimental', 'study', 'of', 'carbon', 'monoxide', '(CO)', 'uptake', 'and', 'clearance', 'during', 'smoking.', 'SUMMARY:', 'A', 'physiologically', 'based', 'numerical', 'model!', 'of', 'carboxyhemoglobin', 'formation', 'during', 'smoking', 'has', 'been', 'developed', 'by', 'modification', 'of', 'a', 'widely', 'used', 'pseudo-equilibrium', 'or', 'averaging', 'model', 'of', 'carbon', 'Monoxide', 'uptake.', 'The', 'modifications', 'have', 'yielded', 'a', 'model', 'that', 'better', 'simulates', 'the', 'smoking', 'process', 'by', 'including', 'the', 'short', 'time', 'scale', 'transient', 'effects', 'of', 'puffing,', 'breathing,', 'and', 'blood', 'flow', 'on', 'COHb', 'concentration', 'and', 'CO', 'uptake', 'and', 'clearance.', 'A', 'wide', 'range', 'of', 'smoking,', 'respiratory,', 'and', 'physiologic', 'input', 'parameters', 'can', 'be', 'varied', 'in', 'the', 'model', 'and', 'their', 'effects', 'on', 'a', 'number', 'of', 'CO', 'and', 'COHb', 'output', 'parameters', 'calculated.', 'This', 'report', 'describes', 'the', 'structure', 'and', 'function', 'of', 'the', 'transient', 'model', 'and', 'reports', 'some', 'new', 'insights', 'not', 'derivable', 'from', 'the', 'prior', 'averaging', 'models.', 'The', 'report', 'also', 'presents', 'numerous', 'simulation', 'results', 'in', 'a', 'format', 'intended', 'to', 'be', 'an', 'accessible', 'primer', 'on', 'the', 'basics', 'of', 'CO', 'and', 'smoking.', 'A', 'background', 'discussion', 'of', 'respiration', 'and', 'smoking', 'is', 'followed', 'by', 'an', 'examination', 'of', 'the', 'variations', 'in', 'COHb', 'concentration', 'both', 'across', 'a', '24', 'hour', 'cycle', 'and', 'during', 'a', 'single', 'smoking;', 'the', 'effect', 'of', 'number', 'of', 'cigarettes,', 'CO', 'per', 'cigarette', 'and', 'CO', 'per', 'puff', 'on', 'COHb', 'levels;', 'estimation', 'of', 'the', 'factors', 'effecting', 'the', 'fraction', 'of', 'CO', 'absorbed', 'from', 'smoke;', 'the', 'half', 'life', 'and', 'clearance', 'of', 'COHb;', 'the', 'similarity', 'in', 'the', 'proportional', 'rise', 'in', 'COHb', 'level', 'throughout', 'the', 'day', 'for', 'different', 'CO', 'yields;', 'and', 'other', 'observations.', 'STATUS:', 'The', 'new', 'model', 'presently', 'stands', 'as', 'a', 'useful', 'theoretical', 'predictor', 'that', 'agrees,', 'where', 'it', 'can', 'be', 'compared,', 'with', 'the', 'literature,', 'but', 'that', 'requires', 'experimental', 'validation', 'in', 'order', 'to', 'reliably', 'exploit', 'its', 'additional', 'predictive', 'power.', 'The', 'experimental', 'assessment', 'is', 'the', 'next', 'step', 'of', 'the', 'project', 'and', 'will', 'be', 'addressed', 'via', 'real', 'time', 'measurements', 'during', 'smoking', 'of', 'exhaled', 'CO', 'concentrations', 'with', 'concurrent', 'puff', 'profile', 'and', 'respiration', 'determinations.', 'KEYWORDS:', 'CARBOXYHEMOGLOBIN,', 'CARBON', 'MONOXIDE,', 'MODELING,', 'RESPIRATION,', 'SMOKING', 'RJRO000000523007355', '‘70080', '7230', 'er00', 'SOZes', ' ', ' ']