Characteristics of Aerosols Generated During Autopsy Procedures and Their Potential Role as Carriers of Infectious Agents

Abstract

Hospital and forensic cranial autopsies require use of a highspeed oscillating saw for removing the skull cap. This procedure generates large quantities of bone dust, liquid aerosols, and large droplets of blood and cerebrospinal fluid. A series of clinical studies was conducted in an autopsy suite of a large teaching hospital in order to characterize the emissions and to determine their concentration in the breathing zone of an autopsy technician. Parameters affecting the rate of particle and droplet emission were determined by conducting a series of laboratory experiments using a portion of skull bone and saline solution, respectively. Both clinical and laboratory data confirmed that the saw blade generates clouds of fine bone dust particles and droplets which could pose a serious inhalation hazard. Concentrations of respirable bone dust as high as 5700 particles/cc were recorded in the breathing zone of the saw operator. Coarse particles and droplets were also generated with trajectories extending up to 50 cm from the saw blade. These could transmit infection following impaction on exposed body surfaces. Current National Institute for Occupational Safety and Health guidelines for the safe conduct of autopsies do not adequately address these hazards. It is recommended that autopsy technicians use a mist-dust respirator instead of a conventional surgical mask as interim protection against respirable particulate. Protection against impinging particles requires eye goggles or safety glasses with side shields. Optimal protection will require development of autopsy techniques that do not generate aerosols. Alternatively, the hazard should be contained within a transparent cabinet built to Class I or Class II specifications.