High wattage e-cigarette vaping induces arterial hypoxemia and tissue hypoxia in tobacco smokers suffering from coronary artery disease: A RCT

Background Whereas high wattage electronic cigarettes (e-cigarettes) vaping (V) is increasingly popular, its health effects are largely unknown. We tested the hypothesis that pure propylene glycol/glycerol e-liquid vehicles V decreases arterial oxygen partial pressure in heavy tobacco smokers suspected of coronary artery disease. Methods After their coronary angiogram, twenty tobacco smokers participated in an open-label randomized parallel study; serial intra-arterial blood samples were performed before and after 1-gram propylene glycol/glycerol e-cigarette V at 60 Watts ( N  = 10) or sham-vaping (SV) ( N  = 10). Peripheral pulse oximetry, transcutaneous gas tension and microcirculatory blood flow were also assessed throughout the experimental sessions. Results Eighty % of the patients were hypertensive and 60% had a left ventricular ejection fraction  – Δ-arterial oxygen partial pressure (SV: + 5.4 ± 3.3 mmHg vs. V: − 5.4 ± 1.9 mmHg; P  = 0.012) (difference between groups; 10.8 [95%CI, 8.4–13.2]mmHg); – Δ-arterial oxygen saturation (SV: + 0.9 ± 0.6% vs. V: − 0.8 ± 0.3%; P  = 0.023); – Δ-oxyhemoglobin fraction (SV: + 1 ± 0.5% vs. V: − 0.6 ± 0.3%; P  = 0.028); – Δ-peripheral oxygen saturation (SV: + 1.3 ± 0.4% vs. V: − 1.3 ± 0.5%; P – Δ-transcutaneous oxygen partial pressure (SV: + 6 ± 3.4 mmHg vs. V: − 1.2 ± 2.1 mmHg; P  = 0.041). The decrease in Δ-peripheral oxygen saturation (SV: + 0.7 ± 0.6% vs. V: − 0.7 ± 0.5%; P  = 0.036) persisted up to 20 minutes after V compared to SV. Conclusions Acute high wattage e-cigarette V in smokers with heart disease induces arterial hypoxemia with subsequent tissue hypoxia. The latter could be related to ventilation/perfusion mismatches.