Withdrawal of cigarette smoking: a study on tracheobronchial clearance

Impact of smoking cessation before resection of lung cancer: a Society of Thoracic Surgeons General Thoracic Surgery Database study

BACKGROUND

Smoking cessation is presumed to be beneficial before resection of lung cancer. The effect of smoking cessation on outcome was investigated.

METHODS

From January 1999 to July 2007, in-hospital outcomes for 7990 primary resections for lung cancer in adults were reported to the Society of Thoracic Surgeons General Thoracic Surgery Database. Risk of hospital death and respiratory complications was assessed according to timing of smoking cessation, adjusted for clinical confounders.

RESULTS

Hospital mortality was 1.4% (n = 109), but 1.5% in patients who had smoked (105 of 6965) vs 0.39% in those who had not (4 of 1025). Compared with the latter, risk-adjusted odds ratios were 3.5 (p = 0.03), 4.6 (p = 0.03), 2.6 (p = 0.7), and 2.5 (p = 0.11) for those whose timing of smoking cessation was categorized as current smoker, quit from 14 days to 1 month, 1 to 12 months, or more than 12 months preoperatively, respectively. Prevalence of major pulmonary complications was 5.7% (456 of 7965) overall, but 6.2% in patients who had smoked (429 of 6941) vs 2.5%% in those who had not (27 of 1024). Compared with the latter, risk-adjusted odds ratios were 1.80 (p = 0.03), 1.62 (p = 0.14), 1.51 (p = 0.20), and 1.29 (p = 0.3) for those whose timing of smoking cessation was categorized as above.

CONCLUSIONS

Risks of hospital death and pulmonary complications after lung cancer resection were increased by smoking and mitigated slowly by preoperative cessation. No optimal interval of smoking cessation was identifiable. Patients should be counseled to stop smoking irrespective of surgical timing.

Lung mucociliary clearance

The aim of this study was to establish reference values for mucociliary clearance and mucociliary clearance reserve capacity as determined by beta 2-adrenergic agonist-induced increase in mucociliary clearance. We studied 62 healthy females (n = 33) and males (n = 29). Their ages ranged evenly between 18 and 84 years. Fifty-three of the subjects were life-long non-smokers, while nine were ex-smokers. Multiple linear regression analyses showed that mucociliary clearance was significantly faster when the radioaerosol was deposited in the central airways than when it was deposited in the peripheral airways, and faster in life-long non-smokers than in ex-smokers. There was no influence of age, and no convincing association with sex. The variation was less within than between subjects. Mean mucociliary clearance reserve capacity was 21.3% (SD: 10.0%, P < 0.0001). The beta 2 agonist-induced increase in lung mucociliary clearance was significantly larger (P < 0.05) than the stimulation which has previously been reported in patients with asthma, bronchiectasis or cystic fibrosis. The signal-to-noise ratio of the mucociliary clearance reserve capacity in relation to measurement of baseline mucociliary clearance indicates that measurement of mucociliary clearance reserve capacity may be a more efficient means of distinguishing between "normal" and "abnormal" mucociliary clearance than single measurement of baseline mucociliary clearance.

Metabolic activity in human alveolar macrophages increases after cessation of smoking

Alveolar macrophages (AMs) were recruited by bronchoalveolar lavage (BAL) from human smokers before and one, three, and six months after smoking cessation. The metabolic activity of the AM was quantified as luminol-enhanced chemiluminescence (CL) both at rest and after in vitro stimulation with phorbol myristate acetate (PMA). The resting CL values did not differ before and after smoking cessation. The activity after PMA stimulation was unaltered at one and three months. However, the maximal metabolic response, as well as the rate, were significantly (P < 0.02 and P < 0.01, respectively) higher at six months, compared to prior smoking cessation. In addition, the time to reach the maximal peak was reduced after six smoke-free months, indicating a more rapid cell activation. The cell concentration in the BAL-fluid decreased (P < 0.001) as soon as after one smoke-free month and remained low at the following lavages. The lower metabolic response one and three months after smoking cessation, and the increased response six months after, together with a rapid normalization of the cell concentration in the BAL fluid, may be explained by the persistence of tobacco-smoke particles in the alveolar space, which could influence cell activity.

Mucociliary clearance and mucosal surface characteristics before and after total laryngectomy

Forty heavy smokers, all males aged between 40 and 70 and affected by laryngeal cancer underwent mucociliary clearance evaluation the day before total laryngectomy, 60 days after and, in 6 of them, 5 years later. Specimens of nasal and tracheal mucosa were obtained during laryngectomy and other subsequent operations. Before total laryngectomy, no significant changes in nasal mucociliary clearance were observed in smokers and controls, and the nasal ciliary carpet was fairly well preserved. Bronchial mucociliary clearance was impaired in all patients, owing to the coexistent chronic obstructive bronchitis. 60 days after the operation, nasal mucociliary clearance was significantly improved when compared with the preoperative data and controls, owing to the increase in the endonasal temperature and humidity, and to the reduction of the nasal blood flow and disappearance of the nasal cycle, which follow tracheostomy. Surface morphologic studies show a change in the squamous epithelium of the anterior third of the nasal fossa into a columnar ciliated one. During the first 3 months after the operation, tracheobronchial mucociliary clearance increased of 50% vis-à-vis the preoperative data. During this period a clinically evident bronchial hypersecretion was observed. The reduction in nasal and tracheobronchial mucociliary clearance function which became evident 6 years after the operation, is probably due to secondary chronic infections.

Tracheobronchial mucociliary clearance in asthma: impairment during remission

Tracheobronchial mucociliary clearance was measured in eight non-smoking patients with asthma in complete remission. The patients were symptom free and required no medication whatsoever for one to six months before assessment. Mucociliary clearance was measured with an objective, radioaerosol technique. For comparison, mucociliary clearance of eight non-smoking, healthy subjects with physical characteristics and pulmonary function similar to those of the asthmatics was also measured on two occasions. In their first assessment the healthy subjects inhaled the tracer radioaerosol under experimental conditions similar to those used for the asthmatics; in the second assessment they inhaled the radioaerosol rapidly to simulate the asthmatic pattern of deposition. Under similar experimental conditions the radioaerosol was deposited more proximally in the asthmatic subjects than in the normal subjects and the difference was statistically significant (p less than 0.01). When, however, the depth of radioaerosol lung penetration was similar in the two groups, there was evidence of a significantly (p less than 0.01) poorer mucociliary clearance six hours after radioaerosol inhalation in the asthmatic than in the healthy group. These findings raise the question whether asthma ever remits completely.

The influence of passive smoking on pulmonary function--a study of 1,351 office workers

Until now it has been difficult to ascertain how much passive inhalation of tobacco smoke affects bronchopulmonary function. To answer this question, an investigation involving 1,351 white collar workers was carried out. Information about active and passive tobacco smoke exposure was obtained by a standardized questionnaire. This made it possible to subdivide the overall group into five subgroups: Never smokers, passive smokers, ex-smokers, current smokers, and other smokers. Forced expiratory vital capacity (FVC) and maximal expiratory flow-volume (MEFV) curves were used for lung function analysis. From these curves FVC, forced mid-expiratory flow (FEF 25/75), forced end-expiratory flow (FEF 75/85), and maximal mid-expiratory flow (MEF 25/75) were determined and standardized for sex, age, height, and body weight. Passive smokers evaluated by this method showed essentially no decrease in parameters describing ventilatory function. It is concluded from the dose-and time-effect relationships obtained in active smokers between the lung function parameters and the duration of tobacco smoke exposure on the one hand and the daily consumption of cigarettes on the other that passive smoking in small doses may have no essential effect on pulmonary function.

Interspecies comparisons of particle deposition and mucociliary clearance in tracheobronchial airways

Inhaled insoluble particles that deposit along normal healthy tracheobronchial airways of humans and other mammals are transported on the proximally moving mucous lining to the larynx, where they are swallowed. The transit time from the most distal ciliated airways varies from 0.1 to 1 d, with each individual having a relatively constant, characteristic time. The exact time course of clearance depends on the distributions of both particle deposition and mucus velocities along the airways. There are too few data on intrabronchial deposition and mucociliary transport rates for laboratory animals to permit a thorough intercomparison among species. However, enough is known about the relative lung sizes and anatomical differences among the various species to make some preliminary, but important, distinctions. As compared to commonly used experimental animals, humans have larger lungs and a more symmetric upper bronchial airway branching pattern. In addition, humans do considerable oral breathing, thus bypassing the effective air cleaning capability of the nasal airways. These differences contribute to a greater amount of upper bronchial airway particle deposition in humans, as well as to greater concentrations of deposition on localized surfaces near airway bifurcations. Airborne irritants that deposit in small ciliated airways may produce marked changes in mucociliary transport. Such materials include cigarette smoke, submicrometer-sized sulfuric acid mist, nitrogen dioxide, and ozone. For cigarette smoke and sulfuric acid, which have been studied for transient effects following single brief exposures in both humans and animals, the responses are similar. Upon repetitive exposures in animals, both of these irritants produce persistant alterations in clearance rates and airway morphometry. Studies of the effects of ozone on mucociliary clearance have, up to now, been limited to tests of the responses of rats to single exposures. The similarities between the known effects of various irritants suggests a nonspecific response.

The effects of smoking on the lungs

The literature relating to tobacco smoking has been reviewed and is discussed under a number of headings. The smoking habits of Australians and people of other countries, the constituents of tobacco smoke and the different types of tobacco are discussed. The effects of tobacco smoke on lung defences and and function are outlined and the evidence relating cigarette smoking to lung cancer in Australia, the UK and the USA is reviewed. The relationship between cigarette smoking and diseases which chronic air flow obstruction is outlined. Differences in smoking-related diseases in males and females and the effects of stopping smoking are included in the discussion.

Tracheobronchial particle deposition and clearance. A study of the effects of cigarette smoking in monozygotic twins

Particle deposition and tracheobronchial clearance were measured in six pairs of male monozygotic twins, four of which were discordant for cigarette smoking. The fraction of an inhaled aerosol that deposited on the ciliated airways showed variations within twin pairs comparable with variations in repeated tests on a single subject, and significantly smaller (P less than .001) than among tests on different subjects. Variations that did occur were consistent with differences in forced expiratory volume (FEV1.0) values. The proximal shift of aerosol deposition and reduced FEV1.0 values in smokers indicated that they had some degree of bronchoconstriction. Mucociliary clearance characteristics are qualitatively and quantitatively similar for nonsmoking and smoking concordant monozygotic twins, ie, comparable with repeated tests on a single individual, reflecting their constitutional similarity. With one exception, clearance curves for twin pairs discordant with respect to smoking were also qualitatively indistinguishable. Nonsmokers, however, had greater upper bronchial clearance rates than their smoking twins.