Acute Effects of Propylene Glycol/Glycerol Intake on Cardiorespiratory Blood Parameters
Phase: NA
Conditions: Metabolic Complication
Sponsor: Université Libre de Bruxelles

 
 
 
Unique Protocol ID : NCT03404011 / B076201733582 
 
Official Title: Acute Effects of Propylene 
Glycol/Glycerol Intake on Blood Parameters 
(AEPGGIB) 
 
Date: 28/01/2018 
 
 

 
 
Acute Effects of Propylene Glycol/Glycerol Intake on Cardiorespiratory Blood 
Parameters 
 
Introduction 
The electronic cigarette is a device generating an aerosol from the "heating" of a liquid (e-liquid), which 
is inhaled (vaping). Propylene glycol (PG) and glycerol (GLY) are the two components for the 
vaporization of flavors and eventually nicotine 1. Its use is booming, in a context where the acute 
effects of inhalation of propylene glycol and glycerol, major components of e-liquid, are poorly known 
at the respiratory, metabolic and hemodynamic levels. 
We emit the hypothesis that GLY and PG which have the same physicochemical properties2, are 
deposited in the pulmonary alveoli and could alter lung gas exchange 3,4. Considering the hydrophilic 
properties of PG/GLY and their small sizes, we believe that there may be a passage of the GLY and the 
PG from the bronchial mucosa to the blood circulation 5. Once in the circulation, the PG/GLY are 
metabolized. GLY notably enters into pathways leading to formation of glucose and glycogen. It may 
also enter in the lipogenesis pathway 6. PG is metabolized by the liver to lactic and pyruvic acid 7. 
We will test the following hypothesis: after inhalation of pure PG/GLY mix (50:50), arterial oxygen 
partial pressure decreases due to the deep-lung deposition of PG/GLY, which alter lung gas exchanges. 
We will also test the transcutaneous oxygen tension with the aim to highlight tissue hypoxia after acute 
nicotine free vaping. We will also assess the presence of metabolic disorders after inhalation of 
PG/GLY, by measuring the changes in pH, lactate, blood glucose, 2,3-bisphosphoglycerate and anion 
gap. 
 
Material and Method: 
 
This is a randomized controlled trial, single blinded, at Saint-Pierre hospital (Université Libre de 
Bruxelles). Thirty patients will be prospectively recruited. The patient will be current tobacco smokers 
between 35 to 80 years old, who will undergo an elective coronarography. At the end of the 
coronarography procedure, if no significant incident has occurred, the arterial catheter will be left in 
place, and the patient will be taken to an adjacent room to the catheterization room for the study. The 
patient will be randomly assigned to the vaping group (inhalation of a liquid composed of 50% PG and 
50% GLY (pharmaceutical grade), without flavors or nicotine) or placebo group (vaping with device 
turn off). In the vaping group, the patient will vape 1 gram of PG/GLY liquid, while in the placebo group, 
the participant will mimic vaping (15 puffs) (We initially intented to perform 35 puffs for the placebo 
vaping group but before initiating the study we decided to match the number of puff performed in the 
active group and in the placebo group). 
 
The following interventions will be carried out: 
 
- 
Arterial blood gas test, according to the following chronology: 1 before the start of the vaping, 
2 after (at 5 and 20 minutes post-vaping). The samples will be taken thanks to the radial arterial 
catheter in a pre-heparinized syringe. The volume of the sample will be of 1 cc. The sample will 

then be analyzed by an automaton (ABL90 FLEX - Radiometer). The parameters studied will be: 
arterial partial pressure in oxygen and carbon dioxide, pH, glucose and lactate. The other 
parameters calculated by the automaton will be: bicarbonate, ions and hemoglobin in its 
various forms (oxyhemoglobin, deoxyhemoglobin, carboxyhemoglobin and methemoglobin). 
- 
Arterial blood sampling: according to the following chronology:  1 samples before the vaping 
and 2 after (at 20 minutes post-vaping). Arterial sampling will be realized thanks to the radial 
arterial catheter on an EDTA and SST tube, at the same time as the arterial blood gas. Four ml 
will be taken for each sample. At the end of the experimental session, the samples will be 
centrifuged at 3500g for 10 minutes, then they will be immediately aliquoted. The aliquots will 
be immediately stored in a refrigerator at -80 ° C for storage for future measurement of the 
2,3-bisphosphoglycerate, CC16, SP-D and metabolomics analysis. 
- 
Cardiac monitoring (IntelliVue MP40 - Philips), will consist of heart rate measurement as well 
as continuous electrocardiogram. The monitoring will be started before the first blood sample 
and before vaping to allow baseline measurements. It will be removed 20 minutes after vaping. 
- 
Pulse oximeter (IntelliVue MP40 - Philipps) will be used to measure the peripheral oxygen 
saturation. The pulse oximeter will be started before the first blood sample, before vaping. It 
will be removed at 20 minutes after vaping. 
- 
The blood pressure will be assessed with an automatic sphygmomanometer (IntelliVue MP40 
- Philipps). The pressure will be assessed 3 times at 2-minute intervals, before vaping to allow 
baseline measurements. It will be measured again 3 times at 2 minutes intervals after vaping, 
as recommended by guidelines. 
- 
A PeriFlux system 5000 (Perimed©, Järfälla, Sweden) will be used to explore the 
transcutaneous oxygen and carbon dioxide tensions by means of a PF 5040 unit and a dual 
transcutaneous O2 and CO2 tensions E5280 electrode. The micro-vascular perfusion in skin 
will also be assessed by a PF 5010 LDPM unit which measures the microvascular flow by means 
of a Laser Doppler. The device will be started  before the first blood sample, at the same time 
as the pulse oximeter, and be removed 20 minutes after vaping. 
 
The following outcomes will be studied:  
 
- 
Arterial Gas partial pressure and saturation of oxyhemoglobin (PO)  
- 
Anion gap, lactate, glycemia, pH, to complete the study of the saturation curve of the 
oxyhemoglobin (SO) 
- 
Arterial 2,3-biphosphoglycerate (SO) 
- 
Arterial metabolomics analysis 
- 
Blood Club cell 16 protein and Surfactant protein-D 
- 
Skin microcirculatory blood flow study 
 
 
Statistical plan 
 
The objective of this study is to determine whether e-cigarette vaping decreases oxygen arterial blood 
concentration. Based on our previous researches, we assume that baseline mean arterial oxygen 
partial pressure will be 100 mm Hg with a standard deviation of 13 mmHg. To demonstrate that e-
cigarette vaping significantly decreases arterial oxygen partial pressure, we assume a reduction in 
arterial oxygen partial pressure of more than 14 mm Hg. We will need 14 patients in each group, with 

80% power to detect a group difference of 14 mm Hg in the change of arterial oxygen partial pressure 
at a two-sided alpha-level of 0.05. 
 
 
Références : 
 
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2013;43:363-90. 
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respiratory tree of electronic cigarette smokers. Environ Pollut 2015; 196: 257–267 
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vapor alters the lateral structure but not tensiometric properties of calf lung surfactant. Respir Res 
2017;18:193. 
5. Robergs RA, Griffin SE. Glycerol. Biochemistry, pharmacokinetics and clinical and practical 
applications. Sports Med. 1998;26:145-67 
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(March 
2002) 
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from, 
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of 
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http://www.inchem.org/documents/sids/sids/56815.pdf] 
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Ethylene Glycol and Propylene Glycol Toxicity. Course: WB 1103. 2007.