[Carboxyhemoglobin in smokers and a preoperative smoking cessation].

The proportion of carbon monoxide-haemoglobin (COHb) in blood was determined before elective surgery on 50 patients (12 women and 38 men; mean age 39.5 [21-68] years) who were smoking at least 20 cigarettes a day, at two moments: during ad lib smoking and after a smoking halt of more than nine hours. 50 nonsmokers (25 women and 25 men; mean age 29.5 [20-48] years) served as controls. COHb proportion before smoking halt averaged 6.9 +/- 1.8%, after halt it averaged 3.8 +/- 1.1% (P less than 0.001). Individual values over 6% were found even after abstinence. COHb proportion in nonsmokers was 1.8 +/- 0.2% (nonsmokers vs. smokers: P less than 0.001 with and P less than 0.01 without smoking halt). The results show that measures to improve oxygen transport capacity, such as blood transfusion or oxygen breathing, are indicated early, especially in an emergency, in smokers and those with uncertain smoking habits. Smoking halt of at least nine hours should be recommended to all heavy smokers before elective surgery.