Acute effects of vaporized nicotine inhalation on human autonomic cardiovascular control

Date
2014
Authors
Pokhrel, Anusheela
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Abstract

Electronic cigarettes (e-cigarettes), battery-operated nicotine delivery devices, have gained popularity among people as a healthier alternative to conventional cigarettes. However, the acute cardiovascular effects of e-cigarettes have not been studied. PURPOSE: This study focuses on the acute effects of e-cigarettes on human autonomic cardiovascular control at rest and during upright tilt. METHODS: Twenty healthy non-smoking subjects, 10 females and 10 males (age 23±1 yrs; height 167±3 cm; weight 63±3) participated in this randomized trial. Subjects participated in two experimental studies separated by at least two weeks. Seated blood pressure and heart rate were recorded after a 10 min period of seated rest, and then subjects inhaled from either a placebo or nicotine cartridge (18mg) for 10 min (20 total inhalations. After an additional seated rest of 10 min, blood pressure and heart rate were recorded again and urine was collected for analysis of cotinine. ECG, beat-by-beat finger arterial pressures and muscle sympathetic nerve activity (MSNA, n=8) were recorded during 5 min of baseline (supine), 5 min of head-up tilt at 70°(tilt) and 5 min of supine (recovery). Subjects controlled their breathing at 15 breaths per minute. Estimation of vagal cardiac control and the sensitivity of the arterial baroreflex were done through the assessment of R-R interval, R-R standard deviation, PNN50, and the sequence method of R-R interval responses to increases or decreases in systolic pressure. RESULTS: Cotinine concentrations were higher after inhalation of nicotine than placebo (p=0.001). Increases in seated arterial pressures were also seen after the inhalation of nicotine (p<0.05). Systolic pressures increased significantly during tilt and diastolic pressure remained significantly elevated in all positions after nicotine inhalation. Increases in MSNA were non-significant during tilt, but were numerically higher than baseline supine and recovery. CONCLUSION: Mild but significant increase of arterial pressure in both seated and passive head up tilt with the inhalation of vaporized nicotine shows that vaporized nicotine inhalation induces a pressor response, but has minimal effect on autonomic control. Increases of arterial pressure in normotensive subjects are likely innocuous, but similar increases in pre- or hypertensive subjects should be studied and assessed for potential chronic health implications.

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Keywords
acute effects of vaporized nicotine, electronic cigarettes, vaporized nicotine
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Department
Health and Kinesiology