The 3 most frequently performed procedures were tonsillectomy, adenoidectomy, and myringotomy with ear tube.6 Data regarding the provider of anesthesia are displayed in Table 2.
The breakdown of perioperative times is displayed in Figure 2. Of the children who received anesthetics, 12,030 were admitted postoperatively to an inpatient facility (data on those patients readmitted after discharge were not available), for a rate of 6 (SE, 1.3) inpatient admissions per 1000 ambulatory anesthetics. An estimated 2,193,686 (SE, 311,507) of the 2,401,626 children receiving ambulatory anesthesia were recorded as having routine discharge (913 of 1000 ambulatory anesthetics; SE, 138).
Payment Information, 2006
In 2006, the cost of 1,547,744 visits to ASCs for children younger than 15 years was paid by private or commercial insurance or through self-pay. For the other visits, the cost of 816,185 visits was paid through public forms of funding (e.g., Medicaid, TRICARE). Of the visits for which funding was known, the cost for 65% of visits was paid from a private or commercial source and for 35% of visits from a government source.
Utilization of ASCs for Children, 1996
In 1996, an estimated 1,522,883 ASC visits included anesthesia administration, which is a rate of 26 ambulatory anesthetic procedures per 1000 children younger than 15 years. Data by age group and type of anesthetic are provided in Table 1. Data regarding the provider of anesthesia are displayed in Table 2.
Payment Information, 1996
In 1996, most (1,142,481) of the ASC visits for children were funded through private or commercial insurance or self-pay; 494,665 (30%) were funded through public sources (including Medicaid and TRICARE). Of the visits for which funding was known, 70% of visits were paid from a private or commercial source and 30% from a government source.
Rate of Inpatient and Ambulatory Tonsillectomy and Adenoidectomy, 1996 and 2006
The rate of inpatient tonsillectomy or adenoidectomy, or both, in 1996 was 0.39 (SE, 0.08) per 1000 children younger than 15 years. In 2006, it was 0.18 (SE, 0.04) per 1000 children of that age. By comparison, the rate of ambulatory tonsillectomy or adenoidectomy, or both, in 1996 was 5.3 per 1000 children younger than 15 years; in 2006, it was 9.7 (SE, 2.0) per 1000 children of that age. Information by age is provided in Table 3.
Over the 10 years between 1996 and 2006, pediatric visits to ASCs during which anesthesia was administered increased almost 50%, from approximately 1.6 million in 1996 to 2.3 million in 2006. During that period, the population of pediatric patients increased only 5.3%, suggesting that the increase in ASC visits requiring anesthesia was the result of a change in overall utilization or a shift in practice from inpatient to outpatient, or both. Overall utilization increased from 26 to 38 ASC visits per 1000 children, representing an almost 40% increase.
Whether this increase in rate of ambulatory anesthesia is attributable to an increase in surgical procedures or a shift of procedures from inpatient to outpatient settings has important implications for health care spending. No data are available that permit a direct comparison of inpatient and outpatient utilization rates for procedures requiring anesthesia.
Therefore, we abstracted the rate of either tonsillectomy or adenoidectomy and of both procedures from the NSAS database and the National Hospital Discharge Survey database, because tonsillectomy and adenoidectomy are common pediatric procedures that may be performed in an inpatient or an outpatient setting and always require anesthesia. The rate of these procedures as an inpatient operation decreased approximately 54% from 1996 to 2006 whereas the rate for the ambulatory setting increased 82%. This change suggests that there may have been a shift of procedures from the inpatient, short-stay hospitals to the hospital-based and freestanding ASCs during these 10 years. This shift is consistent with data from the Medicare Online Survey Certification and Reporting System and the American Hospital Association Annual Surveys of Hospitals, which showed a 28% increase in hospital-based outpatient surgery and a 4.5% decrease in inpatient surgery from 1993 to 2001.2 However, these data must be interpreted with caution because there may be a different explanation for this change. For example, surgeons may schedule tonsillectomies as outpatient procedures in children who stay overnight for payment reasons.
During both 1996 and 2006, the highest rate of ASC visits with general anesthesia administration was in the 1 to 4 years age group and the lowest rate was in the 5 to 14 years age group. Most of the ambulatory pediatric anesthesia was delivered by an anesthesiologist in both time periods (74% in 2006 and 85% in 1996). However, with the increased use of ambulatory anesthesia, the proportion of anesthetics provided by a certified registered nurse anesthetist alone increased whereas the proportion of anesthetics provided by a certified registered nurse anesthetist working with an anesthesiologist decreased (Fig. 3). Nongovernmental groups (private and commercial insurance and self-pay) were the funding source for most visits in both 1996 and 2006.
Economic and Educational Implications
This study is an example of how a database can be used to abstract data useful to health care policy makers, administrators, and educators and to provide important information when changes have to be made in health care systems.
The increase in ambulatory anesthesia itself may be interpreted as an increase in health care spending. However, it may be associated with a decrease in inpatient anesthesia, which could decrease health care expenditures.4 If this trend continues, further savings may occur.
The dramatic increase in pediatric ambulatory surgery has direct implications for residency and fellowship training, and this effect may be the most important impact of this trend. Currently, programs are based at inpatient medical centers, and training at ambulatory anesthesia centers may be limited. As pediatric anesthesia shifts to outpatient and ambulatory centers, education for residents and fellows may need to be adapted to adequately prepare anesthesiologists to manage the unique challenges of ambulatory anesthesia in children.10,11
The main limitations of this study are those inherent to the NSAS database and the medical charts that were reviewed for it, because our study was reliant on data collected by the National Center for Health Statistics for the NSAS database. There was an average response rate of 74% by sampled hospitals in 2006 and 81% in 1996. Data were extracted from the medical records of sampled patients by nonmedical personnel after training,5 and it is possible that the medical abstract form (Appendix) was not uniformly interpreted. This process was also limited by the data that were available and retrievable from the medical records. Information was missing for some cases; specifically, the source of funding was unknown for a large portion of the pediatric ambulatory visits in 2006.
The statistical software we used could abstract data only for specific visits and the primary procedure during the visit. These visits potentially could have included multiple procedures and anesthetics that were counted as 1 visit. Sample size was limited in the pediatric population and, therefore, further data could not be reported because of unacceptable standard errors. Also, the 1996 and 2006 NSAS medical abstracts were not identical. For example, the “not-specified” field used in 2006 was not used in 1996, and thus “not specified” in 1996 was defined as no other field filled. Options for payment source were slightly different in the 2 time periods, and therefore, comparisons cannot be made for this category.
In addition, sampling variables were not available for the 1996 NSAS database and thus accurate standard errors could not be calculated for 1996 data. This lack of sampling variables limited the comparisons that we could make between the 2 time periods. Percentages do not add up to 100% because all data represent estimates based on sampling rates and population size.
The rate of ambulatory anesthesia for children in the US increased by >40% over a decade, partly because of a shift in procedures from an inpatient to an outpatient setting. These databases are useful to health care policy makers, educators, and administrators, as well as other parties involved in health care organization and provision. This type of information is currently of particular importance in this era of health care reform when, to make decisions regarding health care spending and reform, data on utilization of all aspects of health care are needed from all groups.
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11. Twersky RS. Educational protocols in ambulatory anesthesia. Ambul Surg 1997;5:117–9
Medical Abstract Form of the National Survey of Ambulatory Surgery, NSAS-5 (2-1-2006). (Adapted from US Census Bureau and US Department of Commerce. Available at: http://www.cdc.gov/nchs/data/hdasd/nsas_participant/nsas5.pdf.)© 2010 International Anesthesia Research Society