Abstract

Using multiple samples collected via an indwelling venous cannula changes in blood carboxyhaemoglobin (COHb) were studied in five subjects before, during and up to 2½ hr after smoking. On average the smoking, with inhalation, of one cigarette in 6½ min raised the% COHb by 1·6, compared with 2·2 for 24 min of inhaled cigar smoking and only 0·2 for 20 min of non-inhaled pipe smoking. It is suggested that it may be paradoxically safer to smoke high rather than low nicotine cigarettes as those with a high nicotine content will tend to be inhaled less.