Arnold J. Berry

Fatigue in anesthesia: implications and strategies for patient and provider safety.

HEALTHCARE delivery takes place 24 h a day, 7 days a week, and is colloquially termed a “24/7” operation. Anesthesia providers are required to deliver critical around-the-clock care to a variety of patients. This parallels the situation in many other domains that provide such services, e.g., transportation, law enforcement, communications, fire fighting, technology, manufacturing, and the military. Even “convenience” industries (e.g., gas stations and grocery stores) now provide uninterrupted access. These continuous operational demands present unique physiologic challenges to the humans who are called on to provide safe operations within these systems. Human physiologic design dictates circadian patterns of alertness and performance and includes a vital need for sleep. Human requirements for sleep and a stable circadian clock can be, and often are, in direct opposition to the societal demand for continuous operations. Recently, patient safety has taken center stage in health care. The Institute of Medicine’s report “To Err Is Human: Building a Safer Health System,” revealed that medical errors contribute to many hospital deaths and serious adverse events. The response to this report was widespread and included the Quality Interagency Coordination Task Force’s response to the President of the United States, “Doing What Counts for Patient Safety: Federal Actions to Reduce Medical Errors and Their Impact.” 2 This report listed more than 100 action items to be undertaken by federal agencies to improve quality and reduce medical errors. One action promised by the Agency for Healthcare Research and Quality was “the development and dissemination of evidence-based, best safety practices to provider organizations.” In addition to the multiple recommendations to improve patient safety, the report from the Agency for Healthcare Research and Quality included a review chapter on sleep, fatigue,# and medical errors.** There is evidence that the issue of fatigue in health care is coming to prominence on a national level. In April 2001, Public Citizen (a consumer and health advocacy group) and a consortium of interested parties petitioned the Occupational Safety and Health Administration to implement new regulations on resident work hours (table 1). The primary intent of the regulations is to provide more humane working conditions, which the petitioners declare will result in a better standard of care for all patients. Also, the Patient and Physician Safety and Protection Act of 2001, which would limit resident physician work hours, was introduced in Congress. Recently, the Accreditation Council on Graduate Medical Education, the accrediting organization for residency training programs in the United States, has approved common program requirements for resident duty and rest hours that will take effect in July 2003.†† This article is accompanied by an Editorial View. Please see: Lydic R: Fact and fantasy about sleep and anesthesiology. ANESTHESIOLOGY 2002; 97:1050–1.

The risk of needlestick injuries and needlestick-transmitted diseases in the practice of anesthesiology

Anesthesiologists are at risk for acquiring blood-borne infections through contact with blood or body fluids. From prospective studies, the greatest risk of transmission is through a percutaneous exposure such as needlestick injury. Personal protective equipment such as gloves and gowns do not completely prevent these exposures. Although educational efforts can reduce the frequency of recapping of needles, they generally have not decreased the incidence of needlesticks. Therefore, in addition to practicing universal precautions, anesthesiologists can attempt to reduce their risk of needlestick injuries by eliminating nonessential unprotected needle use, through the use of needleless or protected needle devices (engineering controls) and by modifying anesthetic procedures requiring needles (work practice controls). Needleless or protected needle products are commercially available for use in many procedures performed by anesthesiologists. For tasks that require the use of needled devices, the practitioner should use safe techniques for handling (i.e., one-handed recapping if recapping is needed) and disposal (i.e., puncture-resistant containers) of these devices. Evaluation of the efficacy, cost, and safety of needleless or protected needle products should be continued as they are introduced into wider use. Additionally, anesthesiologists should be encouraged to report needlestick injuries so that appropriate postexposure treatment can be given and so that the incident can be studied to permit design of a work protocol or device to prevent similar accidents in the future.

An alternative strategy for infection control of anesthesia breathing circuits : a laboratory assessment of the Pall HME filter

Contaminated breathing systems have been responsible for nosocomial upper respiratory tract and pulmonary infections in patients undergoing general anesthesia. The current infection control guidelines for anesthesia breathing circuits require single-patient use or high-level disinfection of breathing tubes, y-connector, and reservoir bag. An alternative infection control strategy has been suggested that incorporates placement of a microbial filter downstream from the y-connector between the circuit and the patient. This laboratory study assessed the capacity of the Pall HME Filter as a bidirectional barrier to transmission of bacteria between the y-connector of an anesthesia circle breathing system and a test lung. The investigators modified a sterile circle system to allow aerosolization of a suspension of 109 Micrococcus luteus over 5 h into the inspiratory limb proximal to the y-connector or downstream from the filter into the test lung. Cultures indicated that the Pall HME filter placed between the y-connector and the test lung completely prevented transmission of bacteria in both directions. The results of this study suggest that the Pall HME Filter could be used as an effective microbial barrier between the anesthesia circle breathing system and the patient as part of an alternative strategy for infection control.

Multicenter study of contaminated percutaneous injuries in anesthesia personnel.

Background Anesthesia personnel are at risk for occupational infection with bloodborne pathogens from contaminated percutaneous injuries (CPIs). Additional information is needed to formulate methods to reduce risk. Methods The authors analyzed CPIs collected during a 2‐yr period at 11 hospitals, assessed CPI underreporting, and estimated risks of infection with human immunodeficiency virus and hepatitis C virus. Results Data regarding 138 CPIs were collected: 74% were associated with blood‐contaminated hollow‐bore needles, 74% were potentially preventable, 30% were considered high‐risk injuries from devices used for intravascular catheter insertion or obtaining blood, and 45% were reported to hospital health services. Corrected for injury underreporting, the CPI rate was 0.27 CPIs per yr per person; per full‐time equivalent worker, there were 0.42 CPIs/yr. The estimated average 30‐yr risks of human immunodeficiency virus or hepatitis C virus infection per full‐time equivalent are 0.049% and 0.45%, respectively. Projecting these findings to all anesthesia personnel in the United States, the authors estimate that there will be 17 human immunodeficiency virus infections and 155 hepatitis C virus infections in 30 yr. Conclusions Performance of anesthesia tasks is associated with CPIs from blood‐contaminated hollow‐bore needles. Thirty percent of all CPIs would have been high‐risk for bloodborne pathogen transmission if the source patients were infected. Most CPIs were potentially preventable, and fewer than half were reported to hospital health services. The results identify devices and mechanisms responsible for CPIs, provide estimates of risk levels, and permit formulation of strategies to reduce risks.

United States Anesthesiologists over 50 Retirement Decision Making and Workforce Implications

Background:Anesthesiology is among the medical specialties expected to have physician shortage. With little known about older anesthesiologists’ work effort and retirement decision making, the American Society of Anesthesiologists participated in a 2006 national survey of physicians aged 50–79 yr. Methods:Samples of anesthesiologists and other specialists completed a survey of work activities, professional satisfaction, self-defined health and financial status, retirement plans and perspectives, and demographics. A complex survey design enabled adjustments for sampling and response-rate biases so that respondents’ characteristics resembled those in the American Medical Association Physician Masterfile. Retirement decision making was modeled with multivariable ordinal logistic regression. Life-table analysis provided a forecast of likely clinical workforce trends over an ensuing 30 yr. Results:Anesthesiologists (N = 3,222; response rate = 37%) reported a mean work week of 49.4 h and a mean retirement age of 62.7 yr, both values similar to those of other older physicians. Work week decreased with age, and part-time work increased. Women worked a shorter work week (mean, 47.9 vs. 49.7 h, P = 0.024), partly due to greater part-time work (20.2 vs. 13.1%, P value less than 0.001). Relative importance of factors reported among those leaving patient care differed by age cohort, subspecialty, and work status. Poor health was cited by 64% of anesthesiologists retiring in their 50s as compared with 43% of those retiring later (P = 0.039). Conclusions:This survey lends support for greater attention to potentially modifiable factors, such as workplace wellness and professional satisfaction, to prevent premature retirement. The growing trend in part-time work deserves further study.

The Prevalence of Hepatitis B Viral Markers in Anesthesia Personnel

The prevalence of hepatitis B viral markers is increased in some groups of medical workers who are exposed to blood from patients carrying the virus, but this has not been studied critically in physicians and others who administer anesthesia. Physician anesthesiologists (M.D.) and nurse anesthetists and anesthesia assistants (non-M.D.) at four university-affiliated hospitals were evaluated for hepatitis B markers as determined by seropositivity for hepatitis B surface antigen, antibody to the hepatitis B surface antigen, or antibody to the hepatitis B core antigen. In the 86 subjects (38 M.D., 48 non-M.D.) who represented 80.4% of possible participants, the overall prevalence of serologic markers of hepatitis B was 23.3%. The frequency did not differ between M.D. (23.7%) and non-M.D. (22.9%) groups or between men (20.3%) and women (26.9%). Of 81 subjects who had no clinical history of hepatitis, 16 (19.8%) had positive serologic markers. The frequency of seropositivity increased with time since graduation from medical school (M.D.) or nursing school or college (non-M.D.). The prevalence of serologic markers of hepatitis B virus in this study of anesthesia personnel is five to eight times that of the general population but is similar to that of other medical workers who frequently are exposed to blood.

Intraoperative urinary output and postoperative blood urea nitrogen and creatinine levels in patients undergoing aortic reconstructive surgery

Urinary output has been used as a measure of adequate renal perfusion during anesthesia and surgery. In this study, 40 consecutive patients undergoing elective aortic reconstruction were studied to determine whether intraoperative urinary output was predictive of postoperative renal function as measured by blood urea nitrogen (BUN) and creatinine concentrations on postoperative days 1, 3 and 6, or 7. Pulmonary capillary wedge pressures or central venous pressures were kept at or above preoperative values. All patients received 22.5 g of mannitol IV prior to aortic crossclamping. No significant correlation was noted between either mean intraoperative urine output or lowest hourly urine output and postoperative BUN and creatinine concentrations. Complete interruption of renal blood flow in nine of the 40 patients had no significant effect on the correlations. Consequently, intraoperative urine output does not appear predictive of postoperative renal insufficiency in patients undergoing elective aortic reconstruction.

Cause-specific mortality risks of anesthesiologists. New evidence for the existence of old problems.

New Evidence for the Existence of Old Problems SINCE the last mortality study of anesthesiologists was published in ANESTHESIOLOGY, the practice of anesthesiology has undergone a significant transformation. During the last 2 decades, new halogenated anesthetic agents and more complex monitors have been introduced. While caring for patients undergoing diagnostic, therapeutic, and surgical procedures in diverse locations throughout hospitals, ambulatory surgery centers, and offices, anesthesiologists are exposed to equipment that emits X-rays, laser beams, or electromagnetic forces. It has been recognized that infectious agents, such as human immunodeficiency virus (HIV), hepatitis B and C viruses, Mycobacterium tuberculosis, and antibiotic-resistant bacteria can be transmitted from infected patients. The revolutionary transformation in healthcare economics, deployment and night call schedules, and the dynamics of the operating room contribute to jobrelated psychologic stresses. These and other factors undoubtedly have a significant impact on the health and well-being of anesthesiologists. The report from Alexander et al. in this issue of ANESTHESIOLOGY updates our knowledge of causes of death in a sample of anesthesiologists who practiced in this challenging environment. The current mortality study, funded by the American Society of Anesthesiologists (ASA), was proposed to address health concerns raised by anesthesiologists and sporadic reports of diseases to the ASA Committee on Occupational Health. Study protocols were submitted for evaluation in response to an ASA request for proposals. Although the ASA has directly sponsored few major research projects in the past, the organization and its leadership recognized the need to gather data to provide an overall measure of the health of anesthesiologists to address questions that had been raised. Previous mortality studies of anesthesiologists were prompted by concerns regarding the health effects of long-term exposure to trace levels of the halogenated anesthetics that supplanted diethyl ether and cyclopropane. In 1968, Bruce et al. published data regarding causes of death of 441 members of the ASA who died between 1947 to 1966. Compared with control populations of white men from the United States and a group of male life-insurance policy holders, anesthesiologists had increased death rates as a result of malignancy of the lymphoid and reticuloendothelial tissues and from suicide. In a follow-up study, causes of death for 211 ASA members from 1967 through 1971 were compared with that of male life-insurance policy holders. Although the overall age-adjusted death rate for anesthesiologists was less than that of the control group, the rate of suicide was 3 times greater. Contrary to the previous report, there was not an increased risk of malignancy. Subsequently, in consultation with an ad hoc committee of the ASA, Lew compared cause-specific death rates of anesthesiologists (ASA members from 1954 through 1976) with rates for all physicians. The overall death rate of male and female anesthesiologists was less than that of all physicians, but a high rate of suicide was found for anesthesiologists younger than 55 yr. The current study compared cause-specific death rates in anesthesiologists from 1979 to 1995 with those of internal medicine physicians. All-cause mortality did not differ between the two groups, and the standardized mortality ratio for all causes of death in anesthesiologists was 0.48, indicating an approximate 50% lower overall mortality rate for anesthesiologists compared with the general population. When compared with the control group of internists, anesthesiologists had an increased mortality risk that was attributable to suicide, drug-related deaths, other external causes, HIV-related deaths, and cerebrovascular disease. Studies to assess occupational health are complicated by method issues, such as response bias when workers self-report medical conditions. Use of hospital records to document illness provides more accurate information, but these reports may be difficult and costly to obtain. Alexander et al. assessed causes of death, documented by data in the National Death Index, as markers for disease, and they linked these records to the Physician Master File maintained by the American Medical Association. When attempting to determine the potential causes of rare outcomes (premature death in physicians), linkage and analysis of large databases offer several advantages. Primarily, these databases obtain an answer faster and at less cost than does performing a prospective study when prolonged follow-up is necessary. For example, the Framingham Heart Study, which has been in existence for more than 50 yr, has required extensive outlays of capital and resources. The use of a This Editorial View accompanies the following article: Alexander BH, Checkoway H, Nagahama SI, Domino KB: Causespecific mortality risks of anesthesiologists. ANESTHESIOLOGY 2000; 93:922–30. r

Hyponatremia after mannitol administration in the presence of renal failure.

Mannitol, a low molecular weight sugar, is confined t o the extracellular fluid volume af ter intravenous administration. The increased osmolality of the extracellular fluid after mannitol infusion causes water t o move f rom t h e intracellular space into the interstitial a n d intravascular fluid spaces. In t h e kidney, manni tol is freely filtered by t h e normal glomerulus b u t is not reabsorbed. These properties permit intravenously administered mannitol to act both as a diuretic a n d natriuretic substance (1). When mannitol is given t o patients with impairment of renal function, hyponatremia m a y result as water enters the extracellular fluid while t h e mannitol is poorly cleared by t h e kidney (2, 3). Two cases of hyponatremia after administration of large doses of mannitol t o patients with chronic renal failure a r e presented. The fluid shifts occurring after t h e administration of mannitol a r e discussed and recommendat ions for the drug’s use in patients with renal failure are made.

The Effect of Long-term Controlled Mechanical Ventilation with Positive End-expiratory Pressure on Renal Function in Dogs

The effects of 46 h of mechanical ventilation and PEEP on urinary output, sodium excretion, and renal and cardiovascular function were examined. Dogs sedated with sodium pentobarbital were ventilated using one of three modes: spontaneous ventilation (SV), controlled mechanical ventilation (CMV), or CMV with 10 cmH2O positive end-expiratory pressure (CMV with PEEP). Intravenous fluids were given at a constant rate throughout the study and measurements of renal and cardiovascular function were made over four periods. Dogs whose lungs were ventilated with PEEP displayed more than two times the amount of fluid retention seen in the other groups as assessed by mean weight gain. This was due to an initial depression of urine flow, sodium excretion, and free water clearance. Urinary flow rate approximated the rate of fluid infusion by 20 h in SV dogs and by 27 h during CMV, while the maximum during CMV with PEEP occurred at 46 h. There were no significant differences in glomerular filtration rate, renal corticomedullary blood flow distribution, or renal blood flow between groups. During the 46 h, cardiac index increased (SV, +16%; CMV, +19%; CMV with PEEP, +64%), while systemic vascular resistance (SV, –28%; CMV, –30%; CMV with PEEP, –57%), renal vascular resistance (SV, –12%; CMV, –20%; CMV with PEEP, –23%), and mean arterial pressure (SV, –16%; CMV, –15%; CMV with PEEP, –15%) decreased in all groups. This study has demonstrated that when a constant sodium and water load was provided, the SV and CMV groups were rapidly able to adjust the urinary excretion to meet input, while the return of renal function toward normal in the CMV with PEEP group was delayed until almost 46 h from the start of ventilation.