Growth of Nonoperating Room Anesthesia Care in the United States: A Contemporary Trends Analysis

Anesth Analg. 2017 Apr;124(4):1261-1267. doi: 10.1213/ANE.0000000000001734.


Background: Although previous publications suggest an increasing demand and volume of nonoperating room anesthesia (NORA) cases in the United States, there is little factual information on either volume or characteristics of NORA cases at a national level. Our goal was to assess the available data using the National Anesthesia Clinical Outcomes Registry (NACOR).

Methods: We performed a retrospective analysis of NORA volume and case characteristics using NACOR data for the period 2010-2014. Operating room (OR) and NORA cases were assessed for patient, provider, procedural, and facility characteristics. NACOR may indicate general trends, since it collects data on about 25% of all anesthetics in the United States each year. We examined trends in the annual proportion of NORA cases, the annual mean age of patients, the annual proportions of American Society of Anesthesiologists physical status (ASA PS) III-V patients, and outpatient cases. Regression analyses for trends included facility type and urban/rural location as covariables. The most frequently reported procedures were identified.

Results: The proportion of NORA cases overall increased from 28.3% in 2010 to 35.9% in 2014 (P < .001). The mean age of NORA patients was 3.5 years higher compared with OR patients (95% CI 3.5-3.5, P < .001). The proportion of patients with ASA PS class III-V was higher in the NORA group compared with OR group, 37.6% and 33.0%, respectively (P < .001). The median (quartile 1, 3) duration of NORA cases was 40 (25, 70) minutes compared with 86 (52, 141) minutes for OR cases (P < .001). In comparison to OR cases, more NORA cases were started after normal working hours (9.9% vs 16.7%, P < .001). Colonoscopy was the most common procedure that required NORA. There was a significant upward trend in the mean age of NORA patients in the multivariable analysis-the estimated increase in mean age was 1.06 years of age per year of study period (slope 1.06; 95% confidence interval [CI] 1.05-1.07, P < .001). Multivariable analysis demonstrated that the mean age of NORA patients increased significantly faster compared with OR patients (difference in slopes 0.39; 95% CI 0.38-0.41, P < .001). The annual increase in ordinal ASA PS of NORA patients was small in magnitude, but statistically significant (odds ratio 1.03; 95% CI 1.03-1.03, P < .001). The proportion of outpatient NORA cases increased from 69.7% in 2010 to 73.3% in 2014 (P < .001).

Conclusions: Our results demonstrate that NORA is a growing component of anesthesiology practice. The proportion of cases performed outside of the OR increased during the study period. In addition, we identified an upward trend in the age of patients receiving NORA care. NORA cases were different from OR cases in a number of aspects. Data collected by NACOR in the coming years will further characterize the trends identified in this study.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Anesthesia / methods*
  • Anesthesia / trends*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Operating Rooms*
  • Patient Care / methods*
  • Patient Care / trends*
  • Registries
  • Retrospective Studies
  • Societies, Medical / trends*
  • United States / epidemiology
  • Young Adult