We analyzed information provided in the National Electronic Injury Surveillance System (NEISS), maintained by the US Consumer Product Safety Commission (CPSC). For NEISS, injury data is gathered from approximately 100 US hospitals selected as a probability sample of the roughly 5000 hospitals with EDs to provide national estimates of the number of injuries presenting to EDs (US CPSC 2017a). Each selected hospital collects information for patients treated for an injury; information includes a description of the consumer product associated with the injury, patient demographics, diagnosis, disposition, affected body part, and a 142-character narrative of the incident. We analyzed the 2016 NEISS public use data file (US CPSC 2017b).

To identify burn injuries associated with the use of ENDS we first applied a text search to the NEISS case narrative field. We retrieved cases containing any of the following terms: “cig”, “vape”, “vapor”, “ENDS” or “electronic nicotine device”. Our query did not rely on NEISS product codes. The existing product codes were either: not applicable (e.g., electronic cigarettes under product code 1932 “other drug and medications” is used, according to the coding manual, “only for poisonings and chemical burns to children under 5 years of age”), were too broad (e.g. product codes 884 and 883 pertain to any batteries and any battery chargers, respectively), or were not intuitive (e.g., product code 1645 for clothing was applied to burn injuries associated with ENDS failures occurring while the device was in the user’s pocket). Next we restricted to burn-related incidents (diagnosis codes: 46, 47, 48, 49, and 51). Finally, two authors manually reviewed the remaining cases and excluded burns associated with products not in scope including cigarettes and humidifiers. Among the ENDS-related burn cases, we reviewed the narrative field to gain additional insights into the circumstances of the injury.

For this analysis, age groups were categorized as younger than 18 years, 18–24 years, 25–54 years, and 55 years or older. Affected body regions were grouped as upper leg/lower trunk, hand/lower arm, and other body parts (which consisted of the face and lower leg) as these were the most common injury sites. Burn type was reported as thermal, chemical or electrical. Text searches were conducted using the SAS “FIND” function (version 9.4; SAS Institute, Cary, NC). All data analyses were conducted in SAS using PROC SURVEY to account for the sample weights and complex sample design for hospitals. Counts, weighted proportions and 95% confidence intervals (CIs) were calculated. Because only anonymized, publicly-available data were used, the study was considered exempt from human subjects committee review.