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Table 3.10 (below) identifies two studies dependent on video recordings to quantify puffing topography characteristics.

Table 3.10: Topography studies that use video recordings for electronic cigarette topography protocols.

Author

63 NE – Natural Environment

RB – Rebuildable

Hua et al. [55] in 2011 analyzed puff and exhalation duration for individuals using both ENDS and conventional cigarettes in YouTube videos. Videos that clearly showed individuals smoking either ENDS or conventional cigarettes were retrieved randomly. 65 videos were observed with ENDS users in this study. There was a total of 64 ENDS users, 84% were men. The age group ranged from 19 – 45 years old. 25 different user-identified ENDS brands and two unknown ENDS brands were reported in the study.

Puff and exhalation duration were measured using a stopwatch while observing the users in the YouTube videos. A puff was defined as the interval between the LED light switching on and the first vapor being exhaled. Exhalation duration began between the time frame when vapor was expelled from the mouth until the time all vapor appeared to been released. It was determined that 2 – 10 puffs were taken on average during each video. In order to mitigate bias from one observer this study had two observers score the videos for puff and exhalation duration. Inter-observer reliability was determined by dividing the total number of seconds agreed upon by the total number of seconds. The inter-observer reliability for puff duration for an ENDS user was determined to be 96.7% and 91.3% for exhalation duration.

The average puff duration for conventional cigarettes, 2.4 ± 0.8 seconds, differed dramatically compared to ENDS puff duration, reported in Table 3.10 (above). There was no significant difference for exhalation duration amongst the two smoking devices. Further analysis investigated the impact of different brands on topography. By changing brands mean puff duration varied from a low value of 3.6 ± 0.9 seconds to a high value of 5.8 ± 1.4 seconds. Men had more variation and a higher mean puff duration value compared to women.

The data collected in this study relied on observers to determine duration times from YouTube videos. This presents a bias issue from various aspects. The study had two observers in order to moderate this bias however, a quantitative device would help validate the study. The second observation the research team discovered was that there was variation in YouTube videos that seemed to be advertisements. Since companies have influence on how they want to advertise their products neglecting these videos would strengthen the study. Data should be collected on how people smoke these devices naturally instead of how they appear to be smoking. The method to

64 capture times also adds more bias to the values reported. In order to collect time duration, a stopwatch was used while observing the individuals smoking from the videos. Instead utilizing the videos own timing mechanism would have been more accurate since no observer error would be introduced. The research group found in a few cases that a user was clearly draw on an ENDS device before the LED light was turned on. This is problematic because of how the group defined puff duration. There is a profound observer bias when determining duration times because there is no clear explanation of how the definitions look. One observer may believe that all the vapor was expelled but another could believe differently. A device measuring quantitatively would help alleviate this issue.

In a study conducted by Farsalinos et al. [49] a group of 80 subjects, 45 experienced electronic cigarette users and 35 smokers, were recruited. The subjects came from another study evaluating acute clinical effects of using a “medium-strength” nicotine-containing e-liquid. The ECIG group consisted of experienced electronic cigarette users who had more than two months of experience using electronic cigarettes. Smokers were defined as users smoking cigarettes for more than a year and were subdivided into two groups SM-S and SM-E. Smokers that were assigned to smoke cigarettes were a part of the SM-S group and smokers assigned to use electronic cigarettes were a part of the SM-E group. The participants ranged from 20 – 45 years old. All the participants in the ECIG group were former smokers and substituted smoking with electronic cigarettes. They consumed 6 – 12 mg/mL nicotine concentration in the e-liquid on a daily basis. The smokers reported never using any type of electronic cigarette device before the study.

Before data collection the participants were required to abstain from food, coffee, alcohol, smoking and electronic cigarette use for at least eight hours. In addition the researchers explained to the participants how to use the eGo-T rebuildable device. They focused on the coordination between activation of the electronic cigarette device and puff initiation as well as on the need to continuously press the button during the whole duration of a puff. The ECIG and SM-E group used the eGo-T which contained a 9 mg/mL of nicotine concentration e-liquid which was considered medium strength. Topography measurements were gathered from a researcher utilizing a camera to video record the participants. Timing measurements were performed by frame to frame analysis.

The ECIG group was asked to smoke ad lib for 20 minutes while the SM-E group smoked ad lib for 10 minutes. Puff, inhalation and exhalation duration were all measured in this experiment. Puff

65 duration was defined as the interval between when the LED light was activated with the device in the mouth until it was removed from the mouth. Inhalation was defined as the frame when the device was removed from the mouth and just before vapor first became visible. Exhalation was the time between when vapor was visible and when no more vapor came from the mouth.

10 consecutive puffs, which equate to smoking one cigarette, for both the smokers and electronic cigarette users were analyzed in this study. Puffs 1 – 3 were not recorded in order to allow the participants to become acquainted with the device. Therefore, puffs 4 – 13 were the puffs that were recorded and analyzed. There was significant differences observed between the ECIG group and the SM-S group in vaping and smoking patterns. Puff duration for example was doubled in the ECIG group compared to the SM-S and SM-E groups. Inhalation duration, on the contrary, was less for the ECIG group. This study in conjunction with previous studies shows that electronic cigarette users are consuming more of their product compared to smokers. At the five minute mark electronic cigarette users took 13 ± 2 puffs while at the 20 minute mark 43 ± 8 puffs were taken.

All the topography data is identified in Table 3.10 (above).

The original intention of this study was to test another atomizer called eGo-C. Some of the electronic cigarette users reported experiencing overheating of the atomizer a phenomenon called dry puff. Dry puff is an unpleasant, burning taste caused by insufficient supply of liquid to the resistance so that evaporation rate is higher than liquid supply. In response all recordings using the eGo-C were discarded due to the complications and the eGo-T device was used in replacement.

This presents an issue when testing these types of devices. An extra procedure needs to be implemented in order to mitigate dry puff exposure to users when conducting a study. Video observation as a way of collecting data also presents issues since it is a qualitative observation instead of quantitative measurement. This study noted that participants inhaled from the nose during puff drawing, Therefore, measurements of inhalation time corresponded to the inhalation of vapor from the oral cavity. Exhalation was defined as the time when vapor was first visible until no more vapor was coming out of the mouth. However, this assumption could cause problems if the participant is still exhaling but no visible smoke is being observed.