RURAL America has long struggled to achieve and maintain access to quality health care. Thwarting this goal are the interrelated challenges posed by economic stagnation; declining population; disproportionate numbers of elderly, poor, and uninsured; high rates of chronic illness; low volumes of care in small facilities with high fixed costs; and shortages of health care providers. Thus, it is timely that Dunbar et al. describe in this issue of Anesthesiology the workforce available for surgical and obstetric anesthesia in rural Washington and Montana. Their paper is notable less for its message-generally known or at least not surprising to anesthesiologists in community practice-than for highlighting issues underlying national workforce policy discussion, well beyond rural America.
Dunbar et al. found few anesthesiologists in rural Washington and Montana in mid-1994, especially in the smaller facilities and in the most remote rural communities, where nurse anesthetists often were the sole anesthesia care providers. Moreover, the rural hospital administrators whom they surveyed perceived no related threat to their facilities' capabilities to provide high-quality surgical and obstetric care. The authors concluded that there appeared no overall shortage of anesthesia providers in those two states. Their study design did not include evaluation of patient outcomes.
Decades before an emerging glut of specialists limited the mobility of physicians, the determinants of the uneven geographic distributions of physicians, in general, and anesthesiologists, in particular, were studied. In short, as middle-class progeny, like other specialists, anesthesiologists have tended to locate in metropolitan areas, generally favoring both coasts. [3,4]These locations provide access to cultural and recreational activities and to practice opportunities in large tertiary care centers providing the most sophisticated care to the sickest patients. Geographic areas with a lower prevalence of anesthesiologists tend to have a higher prevalence of nurse anesthetists, as a reciprocal relationship. [4,5]* The anesthesiologists' geographic distribution, like those of other specialists and other aspects of care, is depicted in the recently published Dartmouth Atlas of Health Care (Figure 1). 
As one might expect, the variation in geographic distribution of anesthesiologists is even more apparent at the level of the individual hospital. This variation was quantitated for the first time in the early 1980s, when the American Society of Anesthesiologists' (ASA) Committee on Manpower was able to bootstrap a workforce question onto an existing annual survey of hospital administrators, conducted by the American Hospital Association (AHA). With a high response rate, similar to that enjoyed by Dunbar et al., we obtained data documenting the heterogeneous distribution of hospitals and surgical caseloads across communities of different population size (Figure 2).* Most poignant, however, was the large variation in the mix of anesthesia care provider types available to provide anesthesia services in each hospital. Whereas anesthesiologists, either providing direct care or working with nurse anesthetists, were available where 91% of surgical operations were performed, no anesthesiologists were available in the 37% of hospitals that performed the remaining 9% of the national caseload. Facilities without an anesthesiologist tended to be small and rural, with few surgical cases (mean annual caseload, 800).
With a doubling in the supply of anesthesiologists from 1980 to 1994, it has been tantalizing to wonder whether the longstanding shortage of anesthesiologists had been repaired to the extent that anesthesiologists have located in un- and underserved areas. Such a “trickle down” phenomenon had begun for other specialists by the late 1970s. Noting that the per capita presence of anesthesiologists had more than doubled in Montana from 1970 to 1993 and that Montana is among the most rural states (47.6% of its population was rural in 1990 ), Dunbar et al. concluded that anesthesiologists had migrated to rural sites. However, most of its anesthesiologists live in the state's few cities (as judged from their addresses in the ASA Membership Directory). The investigators found anesthesiologists available in only 24 of 62 rural hospitals in Montana and Washington in 1994 (Dunbar et al.'s table 3), whereas the 1981 ASA study* had found an anesthesiologist available in 25 of 81 rural facilities in those states, which is not significantly different (chi squared = 0.643; P = 0.423).
As a result of changes within the AHA, it has not been possible to obtain recent data comparable with that depicted in Figure 2. However, during the latter 1980s and early 1990s, AHA annual surveys inquired about the presence of specific medical specialists on hospital medical staffs. These data also suggest that few anesthesiologists have migrated to rural settings. [10,11]For example, in 1992, anesthesiologists were not available in 32% of hospitals, 82% of which were in rural areas. Whereas the mean annual surgical volume of rural hospitals was 783 cases, that for nonrural facilities was 6141. A hospital was 4 times more likely to have an anesthesiologist if it was in a nonrural location and 2.2 times more likely if its surgical volume was augmented by 1,000 cases. The availability of anesthesiologists in rural obstetric care is even bleaker: Despite small improvement during the previous 10 yr, an ASA study documented that in 1992 no anesthesiologist was available in half of facilities performing fewer than 500 cesarean sections per year. 
How can we reconcile little change in the rural presence of the anesthesiologist with a doubling in our supply? Consistent with our urban predilection, [3,4]anesthesiologists have preferred to remain in familiar urban areas and subspecialize rather than migrate to rural settings. By 1989, ASA membership surveys documented that more than half of the anesthesiologist's aggregate professional time was devoted to recognized subspecialty fields. Also, a survey of anesthesiologists in North Carolina revealed substantial growth in supply, enhanced subspecialization, and minimal migration to unserved areas. Further improvement in the anesthesiologist's rural presence is likely to be minimal or at least slow.
A critical underlying question remains, Is the paucity of anesthesiologists in rural America a health problem? Clearly, there are few anesthetics to be given in any given rural site, and substantial regionalization of surgical and obstetric care already occurs, such that the more complex cases and sicker patients are referred to larger facilities in urban areas. Yet, transfer is not always feasible, and even seemingly mundane cases occasionally pose clinical challenges requiring expert care. Dunbar et al. provide no outcome information. In the absence of direct evidence, however, we perhaps can take small comfort in knowing that limited assessments of the quality of rural surgical and obstetric care have failed to identify major problems. Moreover, the absence of public awareness of health hazards associated with the six-fold variation in the anesthesiologist's geographic distribution depicted in Figure 1may also provide comfort and may stimulate us to question what level of staffing actually is appropriate. [6,11]
Rural America has provided a natural experiment that, some policy makers would argue, shows that nurse anesthetists working without anesthesiologists can deliver satisfactory anesthesia care. This workforce model-of-necessity provides an example of advance-practice nursing, which not only gets the work done, but also frees the anesthesiologist for more demanding services elsewhere. Although not condoning the administration of anesthesia in the absence of an anesthesiologist and until worrisome outcome information is available, we should accept these rural realities. However, it must be acknowledged, casemix and patient outcomes have not been studied in relation to the rural anesthesia workforce. Also, rates of severe adverse events generally are so low that, coupled with the low volumes of care in rural settings, quality of care problems may fall below detection threshold. The natural experiment in rural America provides us with the opportunity to study what types of anesthesia care can be provided safely with different staffing patterns-and which cannot-and understand the appropriate mix of anesthesia care providers needed in other practice settings well beyond rural America.
Fredrick K. Orkin, M.D., M.B.A.
Professor of Anesthesiology and of Community and Family Medicine (Epidemiology); Dartmouth Medical School; Hanover, New Hampshire
*Orkin FK (project director): The Geographical Distribution of Anesthesia Care Providers in the United States, 1981. Park Ridge (IL), American Society of Anesthesiologists, 1983