Handbook of Clinical Anesthesia

Chapter 3

Occupational Health

Anesthesia personnel spend long hours in an environment—the operating room (OR)—filled with many potential hazards, including vapors from chemicals, ionizing radiation, and infectious agents as well as psychological stress engendered by the high-stakes nature of the practice (Berry AJ, Katz JD: Occupational health. In Clinical Anesthesia. Edited by Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC. Philadelphia: Lippincott Williams & Wilkins, 2009, pp 57–81).

  1. Physical Hazards
  2. Anesthetic Gases
  3. Reports on the effects of chronic environmental exposure to anesthetics have included epidemiologic surveys, in vitrostudies, cellular research, and studies in laboratory animals and humans. Areas addressed include the mortality rate and the incidence of fertility and spontaneous abortion, congenital malformations, cancer, hematopoietic diseases, liver disease, neurologic disease, and psychomotor and behavioral changes produced by exposure to anesthetics.
  4. Anesthetic Levels in the Operating Room.Appropriate scavenging and adequate air exchange in the OR significantly lower levels of waste anesthetic gases.
  5. Epidemiologic studiesare difficult to interpret, and results often do not withstand scientific scrutiny.
  6. Reproductive outcomesstudies suggest that there is a slight increase in the risk of spontaneous abortion and congenital abnormalities in offspring of female physicians working in ORs. The routine use of scavenging has been implemented since the time of most of these studies.
  7. Retrospective surveys of large numbers of women who worked during pregnancy indicate

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that negative reproductive outcomes may be related to job-related conditions (e.g., increased work hours, hours worked while standing, occupational fatigue associated with preterm birth) rather than exposure to trace anesthetic gases.

  1. Routine use of scavenging techniques has generally lowered environmental anesthetic levels in ORs and may make it difficult to prove any adverse effects using epidemiologic data.
  2. Neoplasms and Other Nonreproductive Diseases.Overall, there appears to be some evidence that the OR environment produces a slight increase in the rate of spontaneous abortion and cancer in female anesthesiologists and nurses. Mortality risks from cancer and heart disease for anesthesiologists do not differ from those for other medical specialists.
  3. Laboratory Studies
  4. Cellular effects.Nitrous oxide administered in clinically useful concentrations affects hematopoietic and neural cells by irreversibly oxidizing the cobalt atom of vitamin B12from an active to inactive state. This inhibits methionine synthetase and prevents the conversion of methyltetrahydrofolate to tetrahydrofolate, which is required for DNA synthesis, assembly of myelin sheath, and methyl substitutions in neurotransmitters. Inhibition of methionine synthetase in individuals exposed to high concentrations of nitrous oxide may result in anemia and polyneuropathy, but chronic exposure to trace levels does not appear to produce these effects.
  5. Anesthetics are not mutagenic (carcinogenic) using the Ames bacterial assay. Analyses of sister chromatid exchanges or formation of micronucleated lymphocytes to assess for genotoxicity in association with anesthetic exposure have been negative.
  6. Anesthetists working where waste gas scavenging is not used have increased fractions of micronucleated lymphocytes compared with those practicing in ORs with scavenging; the significance of this is unclear.
  7. Reproductive Outcome.Data from animals fail to confirm alterations in female or male fertility or reproduction with exposure to subanesthetic concentrations of currently used inhaled drugs.

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Other possible factors must also be considered, including stress, alterations in work schedule, and fatigue.

Table 3-1 Examples of Recommended Threshold Limits for Occupational Exposure to Anesthetic Agents*

Country

Nitrous Oxide

Enflurane

Isoflurane

United States (NIOSH)

25

2

2

United States (ACGIH)

50

75

Not determined

Great Britain

100

50

50

Norway

100

2

2

Sweden

100

10

10

*Time weighted average in parts per million.
ACGIH, American Conference on Governmental Industrial Hygienists;
NOSH, National Institute of Occupational Safety and Health.

  1. Effects of Trace Anesthetic Levels on Psychomotor Skills.Studies to clarify whether low concentrations of anesthetics alter psychomotor skills are inconclusive.
  2. Recommendations of the National Institute for Occupational Safety and Health (NIOSH)(Table 3-1). Despite the use of scavenging devices, continued monitoring of anesthetic levels in the OR and routine attention to equipment maintenance are needed (Table 3-2).
  3. Anesthetic Levels in the Postanesthesia Care Unit
  4. As patients awaken from general anesthesia, waste anesthetic gases are released into the postanesthesia care unit (PACU), especially if the patient's trachea is still intubated when he or she arrives in the PACU.
  5. NIOSH threshold limits for anesthetic gases can be obtained in the PACU by ensuring adequate room ventilation and fresh gas exchange and by discontinuing the anesthetic gases in sufficient time before leaving the OR.
  6. Chemicals
  7. Methylmethacrylateconcentrations in the OR (allowable exposure, 100 ppm) may be decreased by scavenging devices.
  8. Allergic reactionshave been attributed to exposure of anesthesiologists to vapors of methylmethacrylate and inhaled anesthetics.

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Table 3-2 Sources of Operating Room Contamination

Anesthetic Techniques
Failure to turn off gas flow control vales at end of an anesthetic
Turning gas flow on before placing mask on patient
Poorly fitting masks (especially with induction of anesthesia)
Flushing the circuit
Filling of anesthesia vaporizers
Uncuffed or leaking tracheal tubes (pediatrics) or poorly fitting laryngeal mask airways
Pediatric circuits (Jackson-Rees version of Mapleson D system)
Sidestream sampling carbon dioxide and anesthetic gas analyzers
Anesthesia Machine Delivery System and Scavenging System
Open or closed system
Occlusion or malfunction of hospital disposal system
Maladjustment of hospital disposal system vacuum
Leaks
High-pressure hoses or connectors
Nitrous oxide tank mounting
O rings
CO2 absorbent canisters
Low-pressure circuit
Other Sources
Cryosurgery units
Cardiopulmonary bypass circuits

  1. Latex sensitivityhas become a common source of allergic reactions among OR personnel (12.5 to 15.8% of anesthesiologists are sensitive to latex). Irritant or contact dermatitis from wearing latex-containing gloves accounts for about 80% of reactions to latex (Table 3-3). Use of powderless gloves limits exposure to ambient latex antigens.
  2. Radiation exposure(fluoroscopic guidance procedures, electrophysiology laboratory) is a function of total exposure intensity and time, distance from the source of radiation, and use of shielding.
  3. Radiation exposure becomes minimal at a distance greater than 90 cm (36 inches) from the source.
  4. Pregnant workers should limit the dose to <500 mrem.
  5. Noise pollutionmay approach unacceptable levels in the OR (75 to 90 dB is produced by ventilators, suction equipment, music, and conversation; safe noise exposure level for 8 hours is considered to be 90 dB).

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Table 3-3 Types of Reactions to Latex Gloves

Reaction

Signs/Symptoms

Cause

Management

Irritant contact dermatitis

Scaling, drying, or cracking of skin

Direct skin irritation by gloves, powder, or soaps

Identify reaction, avoid irritant, possible use of glove liner, use of alternative product

Type IV delayed hypersensitivity

Itching, blistering, crusting (delayed 6 to 72 hr)

Chemical additives used in manufacturing (e.g., accelerators)

Identify chemical additive, possible use of glove liner

Type I immediate hypersensitivity

 

Proteins found in latex

Identify reaction; avoid latex-containing products; use of nonlatex or powder-free, low-protein gloves by coworkers

Localized contact urticaria

Itching and hives in the area of contact with latex (immediate)

 

Antihistamines, topical or systemic steroids

Generalized reaction

Runny nose, swollen eyes, generalized rash or hives, bron-chospasm, anaphylaxis

 

Anaphylaxis protocol

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  1. Human factorsthat exist in the OR (configuration and placement of equipment [ergonomics], constant vigilance [mental fatigue], interpersonal relationships, and communication) remain the greatest potential sources contributing to patient morbidity and mortality. Production pressure is an organizational concern that has the potential to create an environment in which issues of productivity supersede those of safety.
  2. Poor communication can lead to conflict and compromised patient safety and has been identified as a root cause of 35% of anesthesia-related sentinel events.
  3. Successful resolution of conflict is a skill that can be learned.
  4. Work hours and night callcan contribute to fatigue and impaired performance of complex cognitive tasks such as monitoring and vigilance. Demands associated with night call have been identified as the most stressful aspect of anesthesia practice.
  5. Sleep deprivation and circadian disruption have deleterious effects on cognition, performance, mood, and health; acute sleep deprivation resembles alcohol intoxication.
  6. Complex cognitive tasks that are specific to anesthesiology (e.g., monitoring, accurate decision making) may be adversely affected by sleep deprivation.
  7. Residents in a sleep-deprived condition demonstrated progressive impairment of alertness and have longer response latency to vigilance probes using the anesthesia simulator, but there are no significant differences in the clinical management of the simulated patients between the rested and sleep-deprived groups.
  8. After a period of sleep deprivation, performance does not return to normal levels until 24 hours of rest and recovery has occurred.
  9. The Accreditation Council for Graduate Medical Education has set duty hours for residents. Although the residents' quality of life has generally improved, the effects on education, reduction in medical errors, and continuity of care are undetermined.
  10. Naps before the start of call as well as the use of caffeine to improve alertness during long shifts.
  11. Infection Hazards

Anesthesia personnel are at risk for acquiring infections from both patients and other personnel (Table 3-4). Viral

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infections are the greatest threat to health care workers and are most often spread by the respiratory route. Transmission of blood-borne pathogens (hepatitis virus, human immunodeficiency virus [HIV]) can be prevented by mechanical barriers or vaccination (hepatitis B). Hand washing between patients, appropriate use of gloves, and use of needleless or protected needle safety devices are the best protections for health care workers from the risks of contracting infections from patients.

Table 3-4 Sources of Infection from Patients

Respiratory Viruses
Influenza A or B (vaccination, amantadine, rimantadine, zanamivir, oseltamivir)
Avian influenza A (vaccination)
Respiratory syncytial virus
Herpes Viruses
Varicella-zoster virus (chickenpox or shingles; susceptible hospital personnel with exposure to the virus should not have direct patient contact from days 10 to 21 after exposure)
Herpes simplex (spread by direct contact with body fluids, such as during tracheal intubation)
Herpetic whitlow (consider limiting direct patient care because this virus can infect susceptible individuals; acyclovir may shorten the course of primary cutaneous infection)
Cytomegalovirus (the source is usually an infected infant or immunosuppressed patient)
Rubella (vaccination is recommended for susceptible health care personnel)
Measles (rubeola) (vaccination is recommended for susceptible health care personnel)
Severe acute respiratory syndrome (SARS; emerging respiratory tract infection caused by coronavirus, high fever followed by headache and occasionally pneumonia and acute respiratory distress syndrome; prevent spread by isolation of infected patients)
Viral Hepatitis
Hepatitis A
Hepatitis B (significant risk for nonimmune health care personnel who have contact with blood and the possibility of needlesticks; vaccination is recommended for susceptible health care personnel)
Hepatitis C (leading cause of chronic liver disease often progressing to cirrhosis; risk of seroconversion after an infected needlestick injury is 1.8%)
Human Immunodeficiency Virus-1
The rate of seroconversion in health care workers sustaining a percutaneous exposure (needlestick injury) is about 0.3%, with conversion usually occurring within 6 to 12 weeks after exposure; the estimated risk of patient-transmitted infection to the anesthesiologist is between 0.001 and 0.129%; universal precautions should be used in managing known and high-risk patients (see Table 3-5)
Creutzfeldt-Jakob Disease
Tuberculosis (increased incidence in immigrants from countries with a high incidence of this disease and in alcoholics, medically underserved persons, immunosuppressed patients, and intravenous drug users)

  1. OSHA Standards, Universal Precautions, and Isolation Precautions
  2. Universal precautions for preventing transmission of blood-borne infections should be used for all patient contacts (Table 3-5).
  3. General infection control practice recommends use of gloves when a health care worker comes in contact with patient mucous membranes or oral fluids, such as during tracheal intubation and pharyngeal suctioning.

Table 3-5 Universal Precautions

1.    All needles, blades, and sharp instruments should be handled so as to prevent accidental injuries, and all of them should be considered potentially infected. Disposable sharp items should be placed in puncture-resistant containers located as close as is practical to the area where they are used. Needles should not be recapped, bent, broken, or removed from disposable syringes before they are placed in appropriate disposable containers.

2.    Gloves should be worn when touching mucous membranes or open skin of all patients. When the possibility exists for exposure to blood, body fluid, or items soiled with these, gloves should be used. With some procedures such as endoscopy, during which aerosolization or splashes of blood or secretions are likely to occur, wearing of masks, eye coverings, and gowns is indicated. Gloves and body coverings should be removed and disposed of properly after patient contact.

3.    Frequent hand washing, especially between patient contacts and after removal of gloves, should be encouraged. If hands are accidentally contaminated with blood or other body fluids, they should be washed as soon as possible.

4.    Ventilation devices for resuscitation should be available at appropriate locations to prevent the need for emergency mouth-to-mouth resuscitation.

5.    Health care workers who have exudative lesions or weeping dermatitis should not participate in direct patient care activities until the condition resolves.

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  1. Viruses in Laser Plumes
  2. Viable viruses have been found in plumes produced by laser vaporization of tissues that contain viruses.
  3. To protect OR personnel from exposure to the viral and chemical contents of laser plumes, it is recommended that the tubing from a smoke evacuator be held within 2.5 cm of the tissue being vaporized.

III. Emotional Considerations

  1. Stressfrom working in the OR (similar to that experienced by air traffic controllers) may reflect an excessive workload, the necessity for making many difficult decisions, night duty, fatigue, increasing reliance on technology, interpersonal tensions, and concerns about liability and night call.
  2. Substance Use, Abuse, and Addiction
  3. Substance abuse (particularly use of potent, short-acting opioids) is often considered an occupational hazard for anesthesiologists.
  4. Causative factors of substance abuse specific to anesthesiology include job stress, lack of external recognition, availability of addictive drugs (need to audit distribution of drugs within the OR), and a susceptible premorbid personality. Propofol abuse has been observed among residents.
  5. Potential consequences of substance abuse are multiple. When an anesthesiologist's professional conduct is impaired to the extent that it is apparent to his or her colleagues, the disease is approaching its end stage (i.e., death) (Table 3-6).
  6. Disciplinary action taken against a physician impaired by substance abuse must be reported to the National Practitioner Data Bank. Health care professionals are affected by chemical dependency (including alcohol abuse) at a rate roughly equivalent to that of the general population (8 to 12%).
  7. The risk of relapse is greatest when all of three factors (family history, major opioid abused, coexisting psychiatric disorder) are present.
  8. Controversy remains about the ultimate career path of anesthesiologists in recovery from chemical dependency. Because of contradictory data, no universal recommendation can be made about re-entry into the practice of anesthesiology after treatment. The

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American Board of Anesthesiology has established a policy for candidates with a history of alcoholism or illegal use of drugs.

Table 3-6 Signs of Substance Abuse and Addiction

Social (Outside the Hospital)
Withdrawal from leisure activities, friends, and family
Uncharacteristic or inappropriate behavior in social settings
Impulsive behavior (overspending, gambling)
Domestic turmoil (separation from spouse, child abuse, sexual problems)
Change in behavior of spouse or children
Legal problems (arrested for driving while intoxicated)
Health
Deterioration in personal hygiene
Accidents
Numerous health complaints (frequent need for medical attention for unrelated illnesses)
Professional (In the Hospital)
Signing out ever increasing quantities of opioids
Sloppy and unreadable charting
Unusual changes in behavior (wide mood swings)
Preferring to work alone, declining relief, frequently relieving others, volunteering for additional cases and calls, staying in the hospital even when not on duty
Frequent requests for bathroom relief
Difficult to find between cases
Insisting on personally administering opioids in the PACU
Wearing long-sleeved gowns (to hide needle marks and combat subjective feeling of cold)

  1. The Aging Anesthesiologist
  2. In contrast to other industries (e.g., commercial pilots are required to take regular medical examinations), little research has been directed toward challenges faced by older anesthesiologists.
  3. An area of particular difficulty for anesthesiologists is maintaining the stamina required for long work shifts and night call.
  4. Mortality Among Anesthesiologists
  5. Studies have reported conflicting data regarding life expectancy among anesthesiologists, including a

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conclusion that the average age at death was the same as the national average.

  1. Death from cancer is not increased among anesthesiologists compared with internists.
  2. Increased risks for anesthesiologists result from drug-related death, suicide, HIV, and cerebrovascular disease.
  3. The risk to anesthesiologists for drug-related deaths is highest in the first 5 years after graduation from medical school but remains increased the entire professional career.
  4. Suicideis an occupational hazard for anesthesiologists, perhaps reflecting the high degree of stress associated with the care of anesthetized patients.
  5. There is a close association between stressful life events and major depressive disorders. In susceptible individuals, feelings of an inability to cope resulting from stress-induced depression can lead to despair and suicide ideation.
  6. A malpractice lawsuit or suspension of privileges may result in suicidal ideation.
  7. Physicians whose privileges to practice medicine have been revoked for chemical dependence are at heightened risk for attempting suicide.

Editors: Barash, Paul G.; Cullen, Bruce F.; Stoelting, Robert K.; Cahalan, Michael K.; Stock, M. Christine

Title: Handbook of Clinical Anesthesia, 6th Edition

Copyright ©2009 Lippincott Williams & Wilkins

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