Handbook of Clinical Anesthesia
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).
- Physical Hazards
- Anesthetic Gases
- 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.
- Anesthetic Levels in the Operating Room.Appropriate scavenging and adequate air exchange in the OR significantly lower levels of waste anesthetic gases.
- Epidemiologic studiesare difficult to interpret, and results often do not withstand scientific scrutiny.
- 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.
- Retrospective surveys of large numbers of women who worked during pregnancy indicate
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.
- 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.
- 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.
- Laboratory Studies
- 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.
- 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.
- 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.
- 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.
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*
- Effects of Trace Anesthetic Levels on Psychomotor Skills.Studies to clarify whether low concentrations of anesthetics alter psychomotor skills are inconclusive.
- 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).
- Anesthetic Levels in the Postanesthesia Care Unit
- 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.
- 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.
- Methylmethacrylateconcentrations in the OR (allowable exposure, 100 ppm) may be decreased by scavenging devices.
- Allergic reactionshave been attributed to exposure of anesthesiologists to vapors of methylmethacrylate and inhaled anesthetics.
Table 3-2 Sources of Operating Room Contamination
- 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.
- 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.
- Radiation exposure becomes minimal at a distance greater than 90 cm (36 inches) from the source.
- Pregnant workers should limit the dose to <500 mrem.
- 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).
Table 3-3 Types of Reactions to Latex Gloves
- 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.
- 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.
- Successful resolution of conflict is a skill that can be learned.
- 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.
- Sleep deprivation and circadian disruption have deleterious effects on cognition, performance, mood, and health; acute sleep deprivation resembles alcohol intoxication.
- Complex cognitive tasks that are specific to anesthesiology (e.g., monitoring, accurate decision making) may be adversely affected by sleep deprivation.
- 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.
- After a period of sleep deprivation, performance does not return to normal levels until 24 hours of rest and recovery has occurred.
- 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.
- Naps before the start of call as well as the use of caffeine to improve alertness during long shifts.
- Infection Hazards
Anesthesia personnel are at risk for acquiring infections from both patients and other personnel (Table 3-4). Viral
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
- OSHA Standards, Universal Precautions, and Isolation Precautions
- Universal precautions for preventing transmission of blood-borne infections should be used for all patient contacts (Table 3-5).
- 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
- Viruses in Laser Plumes
- Viable viruses have been found in plumes produced by laser vaporization of tissues that contain viruses.
- 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
- 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.
- Substance Use, Abuse, and Addiction
- Substance abuse (particularly use of potent, short-acting opioids) is often considered an occupational hazard for anesthesiologists.
- 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.
- 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).
- 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%).
- The risk of relapse is greatest when all of three factors (family history, major opioid abused, coexisting psychiatric disorder) are present.
- 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
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
- The Aging Anesthesiologist
- 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.
- An area of particular difficulty for anesthesiologists is maintaining the stamina required for long work shifts and night call.
- Mortality Among Anesthesiologists
- Studies have reported conflicting data regarding life expectancy among anesthesiologists, including a
conclusion that the average age at death was the same as the national average.
- Death from cancer is not increased among anesthesiologists compared with internists.
- Increased risks for anesthesiologists result from drug-related death, suicide, HIV, and cerebrovascular disease.
- 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.
- Suicideis an occupational hazard for anesthesiologists, perhaps reflecting the high degree of stress associated with the care of anesthetized patients.
- 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.
- A malpractice lawsuit or suspension of privileges may result in suicidal ideation.
- 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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