Suffocation Injuries in the United States

Patient Characteristics and Factors Associated With Mortality

Roula Sasso, MD; Rana Bachir, MPH; Mazen El Sayed, MD, MPH

Disclosures

Western J Emerg Med. 2018;19(4):707-714. 

In This Article

Results

We included a total of 27,381 ED visits for suffocation injuries in the study. The resulting incidence for suffocation injuries in 2013 in the U.S. was 20 per 100,000 ED visits. Inhalation and ingestion of food causing obstruction of respiratory tract or suffocation was the most common presentation (51.6%), followed by suicide and self-inflicted injury by hanging, strangulation, and suffocation (39.3%) (Table 1).

Over half of the patients (54.7%, 95% CI [53.5 – 55.9]) were between 19–65 years. Males (59.1%, 95% CI [57.9 – 60.2]) were more common than females, and most patients had chronic conditions (72.8%, 95% CI [71.8 – 73.9]). The most common body system indicators (defined as a collective designation of body system specific ICD-9-CM codes) were injury and poisoning (80.2%, 95% CI [79.2 – 81.1]) and mental disorders (47.4%, 95% CI [46.2 – 48.5]). The majority of patients had reported injuries on presentation (80.3%, 95% CI [79.4 – 81.2]) and the most common reported method of injury was injury by assault (3.4%, 95% CI [3.0–3.9]) followed by injury by poisoning (2.0%, 95% CI [1.7–2.3]). Patients had mainly minor injuries (Injury Severity Score <15) (99.5%, 95% CI [99.3 – 99.7]). Intentional self-harm was recorded in 40.1% (95% CI [38.9 – 41.2]) of cases with injuries. ED suffocation related visits were similar across all seasons. Most visits (71.9%, 95% CI [70.8 – 72.9]) were during weekdays and Medicare was the most common type of coverage (29.3%, 95% CI [28.3 – 30.0]) (Table 2).

Most patients were either treated and released from the ED (54.9%, 95% CI [53.8 – 56.1]) or admitted to the same hospital as presentation (33.6%, 95% CI [32.6 – 34.7]). Patients who were admitted had an average length of stay of 6.2 days (95% CI [5.8– 6.7]). Overall mortality in the study population was 10.9% (95% CI [10.2 – 11.7]). Mortality rates ranged from 9.6% (95% CI [8.6 – 10.8]) for patients with "suicide and self-inflicted injury by hanging strangulation and suffocation" to 30.7% (95% CI [22.5 – 40.4]) for patients with "hanging, strangulation, or suffocation, undetermined whether accidentally or purposely inflicted." Those with accidental mechanical suffocation had a mortality rate of 11% (95% CI [10.0–12.0]). The mean for total ED charges was $3,620.20 (95% CI [3531.6 – 3708.7]) (Table 3).

We performed a bivariate analysis (not shown) to compare patients' characteristics by outcome (mortality); significant differences were noted between the two groups. Patients who died were more likely to be older, have chronic conditions and be of male gender. They also had more admissions during weekends and had more injuries reported. Higher frequencies of mental health disorders, of intentional self-harm, injury by poisoning and injury by assault were, however, noted in the group of patients who survived. There was no difference in patient outcomes by season of admission or by injury severity.

In the multivariate analysis, factors that were significantly associated with increased mortality after suffocation (Table 4) included male gender (OR [1.3], 95% CI [1.1–1.6]), disease of the circulatory system (OR [11.6], 95% CI [8.9–15.1]), diseases of the nervous system (OR [3.0], 95% CI [2.4–3.8]), diseases of the respiratory system (OR[1.9], 95% CI [1.6–2.4]) and diseases of the genitourinary system (OR [1.5], 95% CI [1.1–1.9]). Additional factors that were also associated with increased mortality included age category 4–18 years (OR [1.8], 95% CI [1.2–2.7]), intentional self-harm (OR [2.0], 95% CI [1.5–2.7]) and having one or no injury reported (OR [1.5], 95% CI [1.1–2.0]). Mental health disorders (OR [0.4], 95% CI [0.3–0.5]) were found to be negatively associated with mortality.

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