Autopsy Biosafety

General Rules

All autopsies or fresh autopsy tissues must be handled as if they contain an infective agent (standard precautions). The entire autopsy area and its contents are designated a biohazard area and posted with appropriate warning signs. The ideal autopsy suite is well ventilated with a negative room pressure airflow exhaust system and contains a separate low-traffic isolation room. Whenever possible, postmortem examinations are carried out during normal working hours by adequate, well-trained staff. It is helpful to have a second autopsy assistant who remains “clean” to record weights, measurements, and other observations, as well as to circulate for any needed supplies. If multiple autopsies are to be performed sequentially, those with the greatest infective risk should be done first, before the staff becomes fatigued. All procedures are carried out in a way that reduces the risk of splashes, spills, droplets, or aerosols. All contaminated equipment, instruments, containers, and so forth should be confined to designated areas (autopsy table, instrument table, dissection area, sink). Paperwork leaving the autopsy suite must not be contaminated, and information from contaminated paperwork can be transferred out of the autopsy suite by photocopy or data-secure photographs.

Attire

For all autopsies, personal protective equipment (PPE) includes scrub suits, gowns, waterproof sleeves, plastic disposable aprons, caps, N95 particulate masks, eye protection (goggles or face shields), shoe covers or footwear restricted to contaminated areas, and double sets of gloves. Cut-resistant and puncture-resistant hand protection (plastic or steel gloves) is also available and certainly recommended for high-risk procedures. A retrospective study has demonstrated their effectiveness in reducing injuries.

Use of Sharp Instruments

One should exercise extraordinary care to minimize the risk of injury from sharp instruments and needles. Whenever possible, the use of needles should be avoided. Needlestick injuries occurring during routine autopsy procedures are entirely preventable; blunt needles and bulb syringes should be used to aspirate fluids in most situations. Because many needlestick accidents occur during disposal of needles, needles should never be recapped after use. Needles and other sharps should be disposed of directly into the approved receptacle; they should not be left lying around the work area.

Accidental self-inflicted cuts, particularly to the distal thumb and index and middle fingers, are the most frequent injuries sustained by pathologists. This type of injury usually occurs during dissection or trimming of tissues for microscopy. The frequency of hand injuries sustained while performing autopsy procedures can be reduced by several simple practices ( Box 3-2 ). A pair of scissors can adequately substitute for a scalpel during most autopsy procedures, including evisceration. The use of blunt-tipped, rather than pointed, scissors for almost all autopsy tissue dissection is advisable. When dissecting with a sharp implement in one hand, one should apply countertraction on tissues by using a long-handled tissue forceps held in the opposite hand; do not hold tissues with the fingers of the noncutting hand. For high-risk cases or dissections, steel-link gloves or some other scalpel-resistant material can be used. Plastic or Kevlar cut-resistant gloves provide protection while still allowing relative dexterity, and we encourage their use whenever possible.

Rib cutters or shears are used to cut the costal cartilage near the costochondral junction during removal of the sternum. Surgical towels should be placed over the cut edges of the ribs to protect against a scrape injury. When making slices of large organs with a long knife, the prosector should use a thick (3-inch) sponge or wadded towel to stabilize the organ with the noncutting hand. When suturing the body wall at the end of the autopsy, hold skin flaps with a large toothed forceps or toothed clamp rather than with a hand.

Limiting Aerosols

Aerosolization of bone dust during the removal of the calvaria or vertebral bodies can be reduced with a plastic cover and/or a vacuum bone dust collector on the saw. A number of systems that use high-efficiency particulate air (HEPA) filtering systems are commercially available. Bone surfaces should be moistened before sawing to cut down the dispersal of bone dust. To limit aerosols, screw cap containers are preferable to snap-top, rubber-stoppered, or cork-stoppered containers. When opening capped containers, cover the opening with a plastic bag to contain aerosols and splashes. Do not overfill a blood specimen vacuum tube by applying pressure through a syringe. When sterilizing tissue before obtaining a culture, be aware that searing tissue with a hot metal instrument can create splatter and a plume of smoke that may contain infectious agents. As an alternative, the organ surface can be sterilized by swabbing centrifugally with an iodine solution.

Photography

Photography of fresh specimens requires the same precautions employed for doing the autopsy, and the camera must be kept clean. In situ photographs obviate the additional risk of moving fresh tissue around the room. Photography of fixed specimens is cleaner and, in this respect, preferable, especially when an infective agent is known to be present. Whether the specimen is fresh or fixed, a pan is used for cleanliness during transport of the organ to the photographic stand. The camera should be handled with clean gloves or by a second person who stays clean. After photographs have been taken, the photostand should be cleaned with disinfectant. Cameras, lenses, and other photographic equipment may be disinfected with a variety of germicidal substances without compromising their functionality. A hands-free camera system would also reduce contamination risk.

Tissue Fixation

Adequate fixation in 10% formalin (containing 3.7% formaldehyde) requires an amount that is at least 10 times the tissue volume; this kills or inactivates all important infective agents except prions and mycobacteria. Embalming fluid containing glutaraldehyde is similarly effective. Mycobacteria remain viable in tissues for days, and these organisms are even difficult to kill with standard formalin fixatives or embalming fluids. Mycobacteria are killed in a fixative of 10% formalin in 50% ethyl alcohol. Adequate time must be allowed for fixatives to penetrate tissues before trimming blocks for histology. Fixation of tissue suspected of containing prions is discussed in a section devoted to prion disorders later in this chapter.