A load of hot air

Despite the widely held belief that air powered weapons are “toys” there are numerous reports in the popular press and medical literature that their use is associated with significant risk of injury. This is highlighted by the case of a 16 year old female who presented to the emergency department following being shot in the neck by an air powered rifle. She displayed no signs of upper airway obstruction and was haemodynamically stable but complained of increasing tightness around her neck. Examination revealed extensive surgical emphysema and a 5 mm entry wound overlying her cricoid cartilage that “whistled” on respiration; there was no exit wound. x Ray revealed a metallic foreign body at the level of C6 in the pre-vertebral soft tissue.

Urgent ear, nose, and throat (ENT), and anaesthetic opinion were sought and the airway was secured following rapid sequence induction. The patient was then transferred to the intensive care unit (ITU). Panendoscopy on day 3 found the cords to be normal with granulation over the entry wound. The patient was extubated and discharged on day 5 with ENT follow up.

There may be as many as four million air powered weapons in the UK and there use is certain to impact on emergency health services¹—for example, the number of criminal offences involving air weapons is increasing from 7568 in 1995 to 10 103 in 2000, which accounted for 60% of all firearm offences in 2000.² There is a corresponding increase in number of associated injuries (1410 in 1995 v 1977 in 2000) and in fact 20% of air weapon offences cause injury.³

Severity of injury depends on the site of the wound, shape of missile, degree of fragmentation, and the extent of cavitation. This in turn is proportional to surface area of impact, tissue density, and the velocity of the missile. Air powered weapons are capable of producing muzzle velocities of 900 ft/sec, which is comparable to many hand guns. Wounding capability may be increased by the use of hunting pellets, “dieseling” (oiling the barrel to cause explosive propulsion of the missile), and “piggybacking” (firing two pellets together). Velocities required to penetrate tissues vary but are well within the limits of air powered weapons—for example, skin at 245 ft/sec, bone at 350 ft/sec, and ocular penetration at only 130 ft/sec.⁴ The risk of injury is well supported by numerous reports of ocular, cranial, vascular, thoracic, and abdominal injuries, some of which are associated with fatalities. Therefore air weapon injuries should be treated as low velocity gun shot wounds depending on the site of injury and any subsequent migration of the missile following appropriate resuscitation.¹

In light of recent high profile firearm incidents gun laws are set to tighten, including measures to limit the use of air weapons. Despite this it is important that health workers in the emergency setting are aware of the risks posed by the use of air powered weapons.