Prevention of Infection Exposure in the Surgical Pathology Laboratory

Introduction

Surgical pathology laboratory accumulates all imaginable infectious material. The diversity of the material with scarce medical history on requisition forms makes the surgical pathology laboratory a special place of concern regarding worker’s infectious exposure vulnerability. The good old times when specimens arrived in fixative are gone forever. The requirements of modern pathology presume ancillary studies which do not tolerate tissue fixation. Under the pressure of turnaround time, the specimen is processed often in fresh state. The surgical pathology laboratory cannot now afford the previous cavalier approach to dangers of infection exposure.

Exposure Control Plans follow the OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030).1 All employees who have occupational exposure to bloodborne pathogens receive initial and periodical training. Annual evaluation process includes safety tests. A surgical pathology laboratory now is incomparable with 20-30 years ago as far as safety concerns apply. However, there are many details of infection exposure that ought to be addressed.

The goals of these materials are:

To summarize OSHA      requirements for infectious exposure specifically for surgical pathology      laboratory.

  1. To draw attention to areas      of special concern for infection exposure in surgical pathology laboratory.
  2. To offer some practical perspectives      of preventive measures.

Although other areas of pathology such as autopsy, cytology, cytogenetic, and clinical molecular biology also have their particularities of exposure to infectious agents, these materials discuss only the surgical pathology laboratory. Adherence to safety precautions in an autopsy suit is stricter than in the surgical pathology laboratory. It is remarkable that the Clinical and Laboratory Standard Institute’s (CLSI) “Protection of laboratory workers from occupationally acquired infection” guidelines devote seven pages to autopsy and one to surgical pathology. 2 However, given the current knowledge of potential infection exposures in surgical pathology laboratory this imbalance is not right anymore.

This article concentrates on grossing in the surgical pathology laboratory as most prone to infection exposure. After tissue processor’s reagents and temperature, the histological block can be safely leaked, as histotechnologists used to say, although it would not be recommended either.

These materials also try to give a personal approach to infection exposure in surgical pathology laboratory based on decades of work in anatomic pathology, especially at the grossing table. Otherwise it would not make any sense to write this article in the first place.

OSHA standards for infection exposure in the surgical pathology laboratory

The OSHA Bloodborne Pathogens Standard (29 Code of Federal Regulations (CFR) 1910.1030) applies to all occupational exposures to blood or other potentially infectious materials (OPIM). The goal of this article is to add specifics of the surgical pathology practice. It is unnecessary to repeat the OSHA official materials although some of them will be quoted. The official Standard’s text is presented in italic.

“Universal precautions” is the fundamental notion of the OSHA Bloodborne Pathogens Standard. According to the OSHA Instructions for Enforcement Procedures for the Occupational Exposure to Bloodborne Pathogens, universal precautions are OSHA’s required methods of control to protect employees from exposure to all human blood and OPIM (Other Potential Infectious Material). The term “universal precautions” refers to a concept of bloodborne disease control which requires that all human blood and OPIM be treated as if known to be infectious for HIV, HBV, HCV or other bloodborne pathogens, regardless of the perceived “low risk” status of a patient or patient population. In regard to the surgical pathology laboratory practice, universal precautions mean that every specimen, as well as the laboratory working areas (grossing tables, reusable equipment) ought to be treated as potential source of infectious exposure.

These materials specifically use the term infectious exposure when OSHA standards prefer blood born and Other Potential Infectious Material (OPIM). Regulations are written keeping in mind predominately clinical settings; because encounters with blood are the main working biohazard for them (syringes, tubes, phlebotomy, etc.). A surgical pathology laboratory is a small part of medical facility. In the surgical pathology laboratory, the “others” (soft tissue, bone, lymph nodes, content of cysts, abscesses, etc.) are dominating.

The OSHA Bloodborne Pathogens Standard includes, besides universal precautions, following main elements:

Engineering and work practice controls; Personal protective equipment; Housekeeping.

Engineering Controls and Work Practices

In the surgical pathology laboratory, the definition of engineering controls usually means specialized equipment. Engineering controls can contribute to infectious exposure prevention besides the standard collection of sharps. Devices for no-hand procedures in handling contaminated sharps, such as for blades removal can be employed, although these devices have limited use. However, correct work practices of removing blades from the handle using instruments (forceps) should be learned and followed as the obligatory practice. By the way, the habit of collecting used sharps in big containers, as often occurs, is wrong for many reasons.

Protection of working equipment as computers boards, photography devices, paper work supplies, and others can be conditionally related to engineering controls. Nevertheless, these actions ought to be done as an infection exposure prevention measure.

Power tools and devices may generate aerosolsas well as be a source for splashing and spattering. Some of these devices include requirement for local exhaust ventilation.

The Standard emphasizes environmental contamination by dried blood on the surfaces, needles, and instruments. This is a very important paragraph [(d) (4) (ii)] keeping in mind air conditioning and ventilation systems when the dried infectious material can be moved far from the working area and working space in the surgical pathology laboratory. This material can become pathogenic if propitious conditions were found (moisture, temperature). In surgical pathology practice it means the necessity immediate mechanical  (with brushes) cleaning, washing in soap detergents, rinsing in abundant water, as well as regular use disinfectants in the end of the working day after cleaning of reusable instruments, cutting boards, and work surfaces. Soaking in detergents overnight and during weekends is the right practice.  Appropriate disinfectants include a diluted bleach solution and EPA-registered tuberculocides (List B), sterilants registered by EPA (List A), products registered against HIV/HBV (List D) or Sterilants/ High Level Disinfectants cleared by the FDA. Despite water is one of the “working tools” while grossing, the readily accessibility and the unit’s fully equipment with antiseptic hand cleaner is important.

Personal Protective Equipment (PPE)

According to OSHA, if engineering and work practice controls do not eliminate exposure, the use of personal protective equipment is required. In the surgical pathology laboratory, it is impossible to eliminate contact with biohazardous material because it is the essence of the procedure. Grossing cannot be automated in the same manner like ina clinical laboratory. The official OSHA materials regarding PPE are voluminous and self explanatory, but they require some comments.

Whether scrubs or laboratory coats, or both, are used, an additional covering is obligatory. Although an apron might be sufficient in many occasion, optimal is a disposable gown like plastic blue aprons. They are easily manageable, though uncomfortable when physical work or in hot ambient temperature.

Masks in combination with eye protection devices, such as goggles or glasses with solid side shields, or chin-length face shields, shall be worn whenever splashes, spray, spatter, or droplets of blood or other potentially infectious materials may be generated and eye, nose, or mouth contamination can be reasonably anticipated.

The use of masks and eye protection is underestimated in the surgical pathology laboratory, although gradually is more and more implemented. However, only a proper use is useful. The practical aspects of mask use will be presented the section “The Protection Mask”.

Eye protection glasses should be an obligatory component of every day PPE in a surgical pathology laboratory. Goggles are impractical and superfluous. By my grim experience of many accidents, I developed a constant rule as stepping in the laboratory with my safety glasses on and keeping them on until I am out from the laboratory. Although this habit came from formalin protection, it is valid for infection exposure. Unfortunately, the modern safety glasses designs try to follow the frame fashions leaving many spaces open that is unacceptable.

Gloves are used in surgical pathology laboratory for protection from infectious exposure, mechanical injury, as well as a barrier of chemical damage to the skin.  In surgical pathology, the work involves manual manipulation including cutting and stretching, where unnoticed piercing might occur under conditions of chemical weakening of the glove’s structure. These circumstances require additional attention to the glove’s permeability. In some situations, it is reasonable to use double gloves (bone processing). It seems that nitrile gloves have some preferences in durability and resistances to stretches that is important in heavy duty work with bones and other large specimens, but for biopsies latex gloves are cheaper and suitable for frequent changing and greater visibility if the glove were damaged although many laboratories do not use them anymore due to an increase in latex allergies.

According to the OSHA Standard, surgical caps or hoods and/or shoe covers or boots shall be worn in instances when gross contamination can reasonably be anticipated (e.g., autopsies, orthopedic surgery). In the surgical pathology laboratory shoe covers are superfluous, but caps would be appropriate for many reason (splashes, aerosols, absorption smells and chemicals by hair), although usually they are avoided except both shoe covers and hair caps are demonstrated in some laboratories when a commission arrives for an inspection, just in case.

HOUSEKEEPING

The OSHA Standard distinguishes between work area and work site. This difference has practical sense for infection exposure prevention in surgical pathology laboratory.

The term “work area” means the area where work involving exposure or potential exposure to blood or OPIM exists, along with the potential contamination of surfaces. In surgical pathology laboratory practice, it means cleaning the working table after completion of grossing procedures that belongs to working practices category that is described before.

 The term “worksite” in the Housekeeping paragraph refers to permanent fixed facilities such as hospitals, dental/medical offices, clinics, etc. In surgical pathology laboratory practice, it means as cleaning with the area immediately adjacent to the work area. The worksite should be responsibly determined by management for housekeeping.

In the surgical pathology laboratory with vast potentially infectious material, the worksite’s floors should be disinfected. A realistic suggestion would be at least surrounding the main working areas as grossing tables/stations, frozen section, accession at the end of the work shift. Disinfection of this worksite should be implemented and controlled.

Periodical scheduled mopping is in addition to everyday cleaning. This procedure requires moving bulky grossing stations which have many areas inaccessible to everyday cleaning, but might be a place of collection of dried blood and OPIM or even a hotbed for pathogenic microorganisms. While choosing equipment for a surgical pathology laboratory, especially grossing stations, the accessibility for cleaning should be considered.

AREAS of special concern regarding infection exposure

Universal precautions provisions ought to start at the specimen receipt and accession level. This area is underestimated in regard of infection exposure prevention. During the accession, the specimen is taken out from the transport bag. The bags and containers sometimes are contaminated with blood or OPIM. Needless to say, that some accidents can occur during the automated transport of specimens, like unpacking of the transportation bags or even the containers. There is a cavalier approach to PPE of accession and housekeeping personnel. All precautions and standards apply in this situation. Additional measures of cleaning and disinfection that should be determined and enforced.

Some surgical pathology specimens are especially significant for the possibility of infectious exposure. They require additional attention of management and workers.

Frozen sections

The frozen section laboratory has the highest level of potential infectious exposure in surgical pathology. The specimen in fresh state is processed in a justifiably rushed pace. By the nature of trimming/cutting, multiple micron size fragments are generated in aerosol form in the cryostat. Aerosols created in cryostats are places where infection could occur for the worker as well for other people in the room.

It is the common understanding that cryostat’s chamber accumulates potentially dangerous infectious materials. Hopefully, time has gone when cryostats were full of remnants of trimmed and cut tissues of previous frozen sections cases. Cleaning of the cryostat’s chamber is everyday routine in most laboratories as a matter of common sense though is not regulated yet.  The cryostat’s defrost cycle continues the cleaning job.

The official CAP Laboratory Accreditation Program check list (ANP. 12807 Phase II revised 06/15/2009) states: Is there a documented procedure for the routine decontamination of the cryostat at defined intervals, and are decontamination records evident? NOTE: The cryostat must be defrosted and decontaminated with a tuberculocidal disinfectant at an interval appropriate for the institution; this must be weekly for instruments used daily. Trimmings and sections of tissue that accumulate inside the cryostat must be removed during decontamination. Although not a requirement, steel mesh gloves should be worn when changing knife blades.

The regulations also state that the cryostat must be clearly marked as contaminated if a frozen section is performed on tissue from a patient known or suspected to be positive for HIV, hepatitis B or C, SARS-related coronavirus, prion disease such as Creutzfeldt-Jakob disease, mycobacterial or systemic fungal disease.  It must then be decontaminated before further use.

Some laboratories use a weekly schedule, some monthly, nobody, I guess, uses steel mesh gloves when changing the blade, but the main thing is to do decontamination diligently and correctly. The method of the cryostat’s chamber cleaning are very much standard. The angel is in details. The bottom line is that decontamination, the process of removing foreign material such as blood, body fluids, does not completely eliminate microorganisms but is a necessary step preceding disinfection.

Here is a possible method of scheduled cryostat chamber’s decontamination and disinfection. The work starts after the cryostat is plugged out and the chamber reaches room temperature. Everything removable, including a blade is taken out from the holder, for separate cleaning. The debris is taken carefully mechanically out by using a brush with a long handle, like Leika’s microtomy brush. Debris must be removed as much as possible because it may hinder the chemical disinfectant access to contaminated surfaces.  Sponges with 70% ethyl alcohol should be used to clean the cryostat’s chamber. Alcohol is most effective in the 70% range because it can penetrate better than absolute alcohol. All cleaning materials should be treated as biohazardous waste and disposed of according to the policies and procedures of the institution.  The liquid waste container also should be emptied. Absorbent  disposable towels with disinfectants are placed (not sprayed to prevent creation of aerosols)onto surfaces of the chamber allowing them to remain in contact with contaminated  surfaces for the length of time specified in the instructions of the  individual agents. After the disinfection procedure is complete, the cryostat and all of the accessories must be thoroughly dried  before being put back into service at cold temperatures. Absolute ethyl alcohol can be used to remove excess moisture from surfaces. Just a practical remainder to lightly lubricate any moving parts because difficulties in cutting during frozen sections create necessity of additional trimming that increases debris (shavings).

There might be different protocols. For example, models which have the heating block filled with 40% formaldehyde during the overnight decontamination cycle. After this process the debris is removed using paper tissue damped with 70% ethanol.

The same procedures are carried out immediately after a case was finished if anything suspected of being an infective agent had been cut. If expected use of the cryostat for the next frozen section, it should be kept in mind that for optimum sectioning, a regular cryostat need 3 hours to reach a proper cooling temperature. Every laboratory that practices frozen section should have at least three cryostats with one of them designated for known or suspected curtain infectious material, e.g. tuberculosis, AIDS, Methicillin-resistant Staphylococcus aureus (MRSA), etc. Additional to three amounts of cryostats depends on the work load.

Cryostat manufacturers offer some models which assure disinfection of the chamber. Although there are no studies in literature of their effectives and reliability, besides manufacturer’s statements, this is a positive tendency.

For example, The Leica’s CM1850 UV 9 is equipped the cryochamber with ultra-violet light (UVC) for disinfection. Vibratome UltraPro 7500 Self-Decontaminating Cryostat offers a spray-jet liquid decontamination (Paroscope sterilization solution which includes peracetic acid and hydrogen peroxide. Decontamination requires 3.5 hours. UV radiation is successfully used in the destruction of airborne microorganisms, but UV light sterilizing capabilities are limited on surfaces because of its lack of penetrating power. The UV light is not sufficient enough to call this decontamination.

Mutually condemned, the most dangerous is the use of freezing sprays which are employed in the rush and desire of getting a better section. A cloud of aerosol particles surrounds the person bend to microtome in the cryostat’s chamber. They can be inhaled or even reach eyes. Although some tricks can be made as spraying the chuck outside the cryostat’s chamber, this method is used rarely in practice due to time and quality of section considerations.

In general, it is unwise to use propellant in regular freezing conditions; especially the modern cryostats provide technical solutions like built-in-Peltier units or cold metal bars that can cool specimens fast. Variants of instant deep freezing, like in liquid nitrogen can be used.

Improvements in quality of cryostat’s freezing can diminish the use of sprays, but the problem exists of section warming during the cutting that leads to uneven and thicker than desired sections. Or, in some occasions, for example, the specimen falls out from the chuck during the cut. Sometimes is necessary to change the position on the chuck and to continue sectioning immediately. Many unforeseen situations occur during the hassle of frozen section.  If the spray were used for some reasons, it is necessary to clearly understand the danger. This brings us to proper work practices education and PPE.

Gradually the requirement of wearing a mask becomes more and more implemented. But what kind of a mask is appropriate for frozen section unit? OSHA does not determine kind of mask specifically for frozen section laboratory. The question of protective mask will be discussed separately.

The second problem related to infection exposure in frozen section unit is a finger cut by the blade. Nobody can work in metal mesh gloves. Although the section usually (with many exceptions) is taken off with a brush, cuttings do occur by some different hardly predictable circumstances,. With experience they occur rarely. The injured ought not to continue to work, as often takes place. Every occurrence of finger cut should be handled like needle stick injury according to the institution’s protocol.

Bone cutting

Bone cutting requires special attention as far as infection exposure is concerned keeping in mind that bone specimens often are grossed in a fresh state (in large specimens it is the only option). The generated during sawing bone dust consists of sharp particles. The particles can be loaded with blood or even infection materials in osteomyelitis or gangrene cases.

Figure 1. Bone and soft tissue fragments after sawing

 

Fragmdent of bone and soft tissue disseminated

This was inside and outside the saw during cleaning

Fragments of bone and soft tissue inevitably disperse around during cutting, especially if power saw were employed (Figure 1). Sharp bone fragments and the saws can be a source of visible and hidden injuries potential for infection exposure.

While grossing bone specimens, some prophylactic measures can be considered.

A/ preference of hand sawing to power sawing.

Hand saws definitely distribute less bone dust loaded with blood droplets. Although the choice of teeth/inch blade of the saw is determined by the bone cutting methodology, the higher is the number the less is an indiscriminate distribution of the bone dust and fragments.  Bone dust collection devices are too bulky for surgical pathology.

B/ obligatory double gloves.

Disposable gloves are notorious for small and often invisible holes. They are highly permeable, especially under conditions of formalin and other chemical exposure. While handling bones, manipulation stretches regular disposable gloves. Even if there were no direct encounters with sawing and cutting instruments, double gloves would be rational as the first line of protection. Blood between gloves is the signal to change both and wash the hands.

Iron impregnated gloves like Kevlar are inconvenient for manipulation, but in longitudinal sawings like in Ewing’s sarcoma when a band saw is used, Kevlar gloves are advisable.  A fabric glove (silky or liner) underneath the nitrile one would not hurt. Ansell’s Touch N Tuff® can make a satisfactory protection due to durability.

C/ eye protection glasses and a face mask is unconditionally obligatory as part of PPE.

Mask will be discussed in a special section below.

D/ special place for bone specimen processing.

It is a common understanding that bone processing requires a special location if not a special room due to inevitable fragment and dust that soils indiscriminately the floor around the bone grossing table. This area can have a special schedule of cleaning that is not affordable for general laboratory.

E/ development of specialized grossing table for bone processing.

A specialized Bone Grossing Table was presented at 37th Convention of National Society for Histotechnology. It was developed by TBJ Inc (Figure 2). The specialized grossing table for bones has a large working space (72” wide x36” deep)  and  intensive backdraft ventilation with high vertical direct flow of the aerosol loaded bone dust/particle filter, removable (easy to clean) perforated exhaust panel with dust/particle filter, adjustable damper for increasing/decreasing airflow and indicator to monitor airflow velocity.  The large surface of the working table provides more opportunities for immobilization tools that prevent distribution of potentially infectious materials in the laboratory.

 

Figure 2. Specialized Bone Grossing Table.

 

Specialization of grossing tables can be a step ahead to fulfill OSHA recommendation of safer medical devices that minimize, control or prevent exposure incidents. A specialized bone grossing table can contribute to prevention of excessive infection exposure while processing bones in surgical pathology.

“Bloody” specimens

Some surgical pathology specimens are “bloodier” than others especially received in a fresh state. Among bloody specimens, the first, of course, is placenta. Everyone, who has cut placenta in a fresh state, experienced a burst of blood on hands, arms, or PPE. Although it looks rational immediately put fixative in the placenta specimen upon receiving, the old protocol is not right under conditions of modern surgical pathology with ancillary studies. Or in a case of monochorionic placenta, there might be a necessity for dye injection. Again, the face mask is obligatory as a part of PPE.

Uterine curretage (“product of conception”) is usually submitteed in a devise SafeTouch Tissue Trap (Figure 3). Opening the lid of the container requires some effort due to negative pressure created by vacuum curreting, the blood can spread on and around the table. However, the most dangerous as a source of infection exposure are specimens of sinus suction which always are sent in SafeTouch Tissue Trap container. Those are real sources of spreading meningococcal and other infection materials. The lid should be open far from the breathing area as much as possible, close to water and exhaust backdraft ventilation and, of course, in the mask without any exception.

Figure 3. SafeTouch Tissue Trap with sinus aspirate.

Amputated extremities, predominately legs, require intensive sectioning with exposure of vessels and inevitably spreading bloody content on the grossing table. Effective immobilization not only provides better conditions for examination but prevents spreading blood or potentially infectious material (Figure 4). There might be different stands for this purpose (see MOPEC’s stands). However, it seems that a simple bucket with water can provide immobilization and accumulation of blood effectively.

 

 

Figure 4. A laboratory backet with water as a stand for grossing an amputated leg.

Gross only specimens often carry bloody tissue fragments that require attention of infection exposure. Although in practice they are treated lightly, in reality all PPE and cleaning procedures should be in place.

The protection mask

The protection mask was mentioned many times in the previous text. It is time for closer look at this critical element of PPE as far as infection exposure prevention is concerned.

OSHA’s Standard requires protection for eyes, the mucous membranes of the face and upper respiratory tract from exposure. Depending on the degree and type of anticipated exposure, the protection for the face would consist of a surgical mask in conjunction with goggles or eye glasses with solid side shields or, alternatively, a chin length face shield.

Health care practice uses different kind of masks which are often defined interchangeably. This terminology confusion is not helpful in informed choice of protection mask. Three terms are in common use: surgical mask, protective mask, and respirators.

A regular surgical mask has two layers (the external thin water permeable, the internal to the face is thick water resistant).   It is obvious that the surgical mask is designed to protect the operative wound from potential infection that stems from the worker. In other words, the aim is to prevent the wearer from infecting others. Thus, if the wearer sneezes, coughs, drools, spits or talks excitedly, his or her infected fluids will be trapped in the mask and will not infect others. It used now by dental hygienists and even by tellers in banks for mutual protection.

In surgical pathology we have a specific goal due to different working conditions. The regular surgical mask’s size and composition is not sufficient. A fountain like splash can be in surgery, but surgery pathology handles specimens with rare occasions (placenta, big cysts) of splashes.

The respirators, or N95 masks, are two grades: for industrial use and fluid resistant mask for use in hospitals and clinical settings. The nomenclature N95 comes from the fact that these masks are supposed to filter at least 95% of all particulates that are 3 microns or larger The N95 mask was recommended by the Centre for Disease Control & Prevention (CDC) and World Health Organisation (WHO) as the respiratory protection for the bird flu virus. This mask requires individual fit-testing to be functional according their design and purpose. Reasonable in theory, the N95 mask is cumbersome, uncomfortable, and therefore unpractical for a regular surgical pathology laboratory work.

The third type of protection masks are different variants of shield masks. The most popular is Kimberly-Clark TECNOL FLUIDSHIELD mask. It has five layers. Both, internal and external (orange stripes) are water permeable. Three layers between them have different degree of water resistance. Although the company advertises them as LONCET breathable film, these layers, in my experience, make the mask uncomfortable for a prolonged use because the area between the mask and the face is overheated and over saturated with exhaled carbon dioxide that decreases the percentage of oxygen in the inhaled air.
As it was already mentioned, the frozen section laboratory is the most dangerous area for infection exposure. CLSI guidelines unequivocally state that “an N-95 particulate respirator should be worn during frozen sectioning.” 2However it is an unrealistic recommendation for many reasons (difficult to breathe, individual fit-testing, necessity of permanent communication); although for some exquisite cases such an option should be on hand. Even a Kimberly-Clark FLUIDSHIELD mask is superfluous, except for initial sections of a cystic formation or other possible splash specimen. A regular surgical mask with earloops is obligatory and should be enforced on technicians and pathologists without any exception.

While handling “bloody specimens”, the worker would definitely benefit from face shielded masks like Kimberly-Clark (Figure 5.).

 

Figure 5. Kimberly-Clark FLUIDSHIELD mask with blood spots

Bone grossing requires Kimberly-Clark mask, because so called “ballistic trajectory particles” of bone dust ought to be prevented to reach not only mucous membranes but also the skin of the face and neck.

While doing biopsies with hematoxylin inking for visibility during embedding, I noticed droplets of stain that often appeared on the upper part of the protective gown. When I turned the mask upside-down, those droplets appeared on the plastic shield.  I realized that it is more reasonable to wear the Kimberly-Clark mask with the plastic shield upside- down. 3The chin and the neck are more protected from splashes and spatters. Additionally, the area of air circulation is larger in this situation. The shield reaches the ubiquitous blue protective gown like Convertors (ALLEGIANCE’s Impervious Gown w/Thumb hooks, Universal). One lower fold of the mask can be loosened to make the mask longer or the plastic shield can be cut to make it shorter if it is necessary for the individual adjustment. The lower strips can be tightened or loosened around the neck depending on the type of the processed specimen. The protective glasses should be worn above the strings of the mask to get more protection. The use of protective glasses with solid side shields is both, the OSHA’s requirement and a necessity without any exception (Figure 6.).

 

 

 

 

 

 

Figure 6. Kimberly-Clark TECNOL FLUIDSHIELD mask upside- down

A protective mask for the surgical pathology laboratory still is waiting a special design. It requires a different conceptual approach keeping in mind specifics of surgical pathology specimens, hours of work, and versatility of functions during grossing and frozen section.

Mechanical injury

All my injuries had occurred during experimentations, sometimes silly and risky, predominately while doing autopsies, but never during work in surgical pathology because I strictly followed safe work practice: never used my hands instead of forceps, always moved the knife/blade in right direction away from myself, etc.

A needlestick in surgical pathology occurs rarely but requires a differential approach depending on the grossing situation. A needlestick during manipulation with a placenta should be handled the same as in a clinical setting.

Every injury during cutting/sawing in surgical pathology laboratory is a potential infection exposure. On the other hand every such accident is a result of violation of safe work practices, in most instances by negligence. Implementation of details of safe work is responsibility of management and workers. First aid in surgical pathology laboratory should be oriented on prevention of infection exposure.

Some final considerations

The OSHA standards are understandably oriented on the employer’s responsibilities- but what about emploess’ responsibility? These materials, while keeping the OSHA standards as an obligatory framework, try to concentrate attention predominately on safe work practices that require knowledge and self discipline. Personal responsibility is the key.

While working in anatomical pathology in different positions, I gradually developed more serious attitude towards many aspects of safety, especially infectious exposure. This change occurred in parallel with changes in the surgical pathology laboratory environment. The specimens are grossed more often in a fresh state. The amount of frozen sections increased dramatically. A different set of microorganisms are in play (HIV, Hepatitis B and C, Methicillin-resistant Staphylococcus aureus (MRSA) and TB resistant strains). Central air is a friend and might be an enemy by moving around pathogenic microorganism in aerosol form under conditions of less careful cleaning of the laboratory rooms by “scheduled” housekeeping.

On the other hand, is not the harmful effect of infection exposure in the surgical pathology laboratory exaggerated? Do we have enough data to support the protective measures which cost money and impose hardship while wearing PPE? These questions cannot be dismissed out of hand.

Actually, microbiology laboratory data are in the focus of the most biosafety literature. 4, 5,6,7They show that the risk for laboratory-acquired infection in the microbiology laboratory is higher than for the general population. However, these data cannot be extrapolated to the surgical pathology laboratory for obvious reason that the latter does not handle cultures of microorganisms. In surgical pathology laboratory the infectious material is dispersed in incomparable lower concentrations, although, unfortunately, in potentially dangerous aerosol form.

In May 2008, the Center for Disease Control and Prevention (CDC) convened Blue Ribbon Panel for Issues of Clinical Laboratory Safety to address incidence of laboratory-acquired infection. There is a statement in the summary that “Neither the number nor the causes of LAIs [laboratory-acquired infections] in clinical laboratories is fully known.” The panel concluded that “more work is still needed.”8

There is a discrepancy between stricter adherence to safety precautions in surgical pathology laboratory and the autopsy room with prevalence in the latter. (It is remarkable that already mentioned CLSI’s manual devotes seven pages to autopsy, and one for surgical pathology. This is the heritage of old perceptions. It is true that a dead body is more prone to develop infection unrestricted by bactericide features of the blood and immune system of the living organism, especially when refrigerators were limited in old morgues. Blood is sterile except sepsis. Even if it contains microorganisms they are in minuscule amount.

An acute leukemia diagnosis could be made only by looking at the corpse. However, the dead bodies do not distribute airborne infection, in most cases there is known premortem documentation. Nobody can argue that autopsy does not require safety precautions, but, in my opinion, the modern surgical pathology laboratory definitely is more dangerous place that autopsy room as far as infection exposure is concerned.

The Center for Disease Control (CDC) convened Blue Ribbon Panel for Issues of Clinical Laboratory Safety in May 2008. The executive summary that emerged from that panel notes that “Neither the number nor the causes of LAIs [laboratory-acquired infections] in clinical laboratories is fully known,” “the ability to determine and monitor the frequency of such occurrences is desirable,” and that while “many professional, accrediting, training, and standards development organizations are already making efforts to address the safety of laboratory workers,” “the panel felt that more work is still needed.”

In the surgical pathology laboratory, this work will be never completed for two reasons. The amount of infectious material is not enough to generate a clinically apparent disease that can be included in significant statistics and fortunately, the OSHA requirements will prevent the laboratories from collecting data for statistically reliable cohort studies. If a laboratory worker becomes ill with tuberculosis, a single occurrence does not prove anything.  I performed dozens of autopsies on deceased from cavernous lung tuberculosis with only a lab coat and gloves on remaining TB negative, but this also does not suggest that TB encounters are harmless.

Like in the case of formalin cancerogeenity for surgical pathology workers will be never now unequivocally proven or objected. Petencoffers experiment when he drunk a glass of water with cholera vibrions unharmed, would be useless in proof or dismiss the consequences of infection exposure in surgical pathology laboratory. The constellation of all scientific and empirical data that forms the background of common sense laid the foundation of preventive measures that reject cavalierly approach to infection exposure.

Previous experience of generations of anatomical pathology workers who had not followed the current preventive rules is useless because they functioned under different environments conditions (grossing specimen in fresh state, ventilation, different housekeeping, etc.) Ventilation is a friend and an enemy as far as infection exposure is concerned.

Previous saturation with formalin might be also a preventive measure. Obsession with cancerogenity eliminates exposure but this is not healthy, unless formaldehyde damages the protective level of body (mucuous layers, respiratory tract villia)

There might be some disputable approaches to the effects of infection exposure in the surgical pathology laboratory (see the website “Grossing Technology in Surgical Pathology” link Safety, www. grossing-technology.com). The website presents the issue in an immunological aspect.

While doing work in the surgical pathology laboratory, it does not make any sense to take chances by infection exposure. These materials are focused on implementation of OSHA Bloodborne Pathogens standards through rational work practices. The angel is in details.

See also the post Ebola Highlights Work Place Safety

References

1. Bloodborne Pathogens, 29 C.F.R. Sect. 1910.1030 (2008).

2. Clinical and Laboratory Standard Institute (CLSI): Protection of Laboratory Workers from Occupationally Acquired Infections; Approved Guideline—Third Edition, M29-A3 Vol 25 No. 10 2005.

3. The Upside-down Kimberly-Clark FLUIDSHIELD Mask. Grossing Technology in Surgical Pathology (www. grossing-technology.com), Link Equipment, Instruments, Gadgets. Accessed July 2011.

4. Pike RM. Laboratory-associated infection: incidence, fatalities, causes, and prevention. Annu Rev Microb. 1979; 33: 41-66.

5. Sewell DL. Laboratory associated infections and biosafety. Clin Microbiology Rev. 1995; 8: 389-405.

6.  Walker D and Campbell D.  A survey of infections in United Kingdom laboratories, 1994-1995. J Clin Pathol. 1999; 52: 415-418.

7. Lim PL, Kurup A, Gopalakrishna G. et al. Laboratory-acquired severe acute respiratory syndrome. N Engl J Med. 2004; 350:1740-5.

8. Singh K. Laboratory-Acquired Infections. Clin Infect Disease. 2009; Jul 1; 49(1):142-7.

9. Anne Ford. Taking Stock in Biosafety in Surgh Path. CAP TODAY, 2009.

Acknowledgement

Thank you, Dr. Anjali Godambe, MD Loyola University Chicago Medical Center, for help in preparation of this article.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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