Passive smoking acutely affects the microcirculation in healthy non-smokers

Abstract

Objective: Acute effects of passive smoking on microcirculation have not been sufficiently studied. The aim of the present study was to detect microcirculatory alterations in healthy non-smokers after passive exposure to cigarette smoke, utilizing the Near Infrared Spectroscopy method combined with the vascular occlusion technique.

Methods: Sixteen (9 females, age: 34 ± 9 years) non-smoking, healthy volunteers were exposed to passive smoking for 30 min in a temperature-controlled environment. Smoke concentration was monitored with a real-time particle counter. The following microcirculatory parameters were estimated: baseline tissue oxygen saturation (StO₂); StO₂ decrement after vascular occlusion (indicating the oxygen consumption rate); StO₂incremental response after vascular occlusion release (reperfusion rate); the time period where the StO₂ signal returns to the baseline values after the hyperemic response.

Results: Baseline StO₂ (79.6 ± 6.4 vs. 79 ± 8%, p = 0.53) as well as the time needed for StO₂ to return to baseline levels (138.2 ± 26.5 vs. 142.1 ± 34.6 s, p = 0.64) did not significantly differ before vs. after passive smoking exposure. Oxygen consumption rate decreased after 30 min exposure to passive smoking (from 12.8 ± 4.2 to 11.3 ± 2.8%/min, p = 0.04); Reperfusion rate also significantly decreased (from 5.6 ± 1.8 to 5 ± 1.7%/s, p = 0.04).

Conclusions: Our results suggest that acute exposure to passive smoking delays peripheral tissue oxygen consumption and adversely affects microcirculatory responsiveness after stagnant ischemia in healthy non-smokers.

Keywords: Endothelium dysfunction; Microcirculation; Near-infrared spectroscopy; Passive smoking; Vascular reactivity.