Airways Response to Inhaled Tobacco Smoke: Time Course, Dose Dependence and Effect of Volume History

Silva, A.M. Taveira Da; Hamosh, Paul

doi:10.1159/000194365

Cited by 9 publications

(1 citation statement)

References 17 publications

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“…This bronchoconstrictive effect is due to stimula tion of vagal irritant receptors in the air ways and is abolished by pretreatment with atropine [1,2]. We described the acute effect of smoking on the maximum expiratory flow volume (MEFV) curve as being characterized by a small drop in maximum expiratory flow at 50% of the vital capacity (FEFi0) [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Effect of Smoking a Cigarette on the Density Dependence of Maximal Expiratory Flow

Silva¹,

Hamosh²

1982

Respiration

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We have shown that tobacco smoke causes an increase in airways resistance and a drop in expiratory flow at 50% of the vital capacity (FEF₅₀). To better define the nature and site of this bronchoconstrictive effect we measured maximal expiratory flow while breathing air and a low-density gas mixture (helium-oxygen), in 12 healthy volunteers, before and after smoking a cigarette. There was a significant drop in FEF₅₀ while breathing air (FEF₅₀Air) (5.52 ± 1.83–5.05 ± 1.86 liters/s; p < 0.001).No changes were observed in the helium-oxygen FEF₅₀ (FEF₅₀He) after smoking. The increase in FEF₅₀ after breathing the low-density gas as a percentage of FEF₅₀Air (ΔVmax₅₀) increased from 47.1 ± 11.4% before smoking to 57.0 ± 13.3% after smoking (p < 0.05). There were no changes in forced vital capacity (FVC), flow at 75% FVC and volume of isoflow. We discuss these observations in light of the equal pressure point (EPP) analysis and wave speed theory of flow limitation. We conclude that after smoking flow becomes more density dependent because there is constriction of a flow-limiting segment downstream from the EPP, located in lobar and segmental bronchi. No acute effect of tobacco smoke on the small airways could be demonstrated.

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Section: Introductionmentioning

confidence: 99%

Effect of Smoking a Cigarette on the Density Dependence of Maximal Expiratory Flow

Silva¹,

Hamosh²

1982

Respiration

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Laser smoke effect on the bronchial system

et al. 1987

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The photoresection of endobronchial tumors produces smoke which is partly inhaled by the patient as well as the surgical staff. In an animal study we investigated whether a single exposure or repetitive exposures to smoke might have harmful side effects on the airways. Eleven sheep were exposed to smoke produced by laser-vaporizing (6,500 J) sections of bronchial tissue (1 cm3) in a Plexiglas chamber. The smoke analysis revealed 0.92 mg/liter particles with a mean particle size of 0.54 micron. Carbon monoxide content was estimated as 0.04%. We measured the effects of one or three separate ten-minute exposures on airway resistance, gas exchange, and mucociliary clearance rate in the trachea. We found that the smoke inhalation resulted in a decrease of arterial PO2 with relatively little change in airway mechanics. Tracheal mucus velocity, a marker of lung mucociliary clearance, was significantly depressed in a dose-dependent manner with increasing smoke exposures. Results of bronchoalveolar lavages performed before and one day after the exposure showed that the smoke inhalation induced a severe inflammation with dramatic increases of inflammatory cells. The total number of cells per milliliter lavage return increased from 3.2 million to 25 million; percent neutrophils increased from 2.3 to 45.6% and percent macrophages decreased from 86 to 41%. These findings indicate that the side effects of smoke inhalation during intrabronchial laser surgery should not be neglected. The impairment of the defense mechanism of the lung combined with the inflammation as well as hypoxia might be fatal in compromised patients. Effective smoke removal devices should be developed to protect the patient as well as the surgeon.

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