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Letters to the Editor: Letter to the Editor

Use of the American Society of Anesthesiologists Physical Status Classification System in Research

Kopp, Vincent J. MD, FAAP

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doi: 10.1213/ANE.0b013e31829ec1bc
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To the Editor

The March 2013 issue of Anesthesia & Analgesia contains articles describing 12 human studies. Of the 12 studies, 8 mention the American Society of Anesthesiologists Physical Status Classification System (ASA PS CS) and 1 annotates the ASA PS CS source used.1 This reference refers to a 1978 publication.2

This raises a question: When the ASA PS CS is used, shouldn’t meticulous referencing follow? As outdated3 and mutated forms4 of the “ASA class” remain extant in journals and on the Internet, editors, reviewers, and readers deserve to know which version a study uses for data reporting.

Obviously, clinicians make different patient assessments.5,6 Clinical researchers, though, require low interobserver variability to assure data they report are accurate. The research solution is to urge investigators to prospectively apply and cite the ASA PS CS as found on the ASA Web site.7 Alternatively, editors should require citation of any version actually used when data were gathered. If no standard was applied or chance prevailed when ASA PS CS data were gathered, this should be made explicit. Last, research into cognitive factors that influence how decisions about ASA PS CS assignment are made may help clinical investigators better apply this too-often misapplied tool.8A&A can lead in all 3 areas by starting to require accurate citation when the ASA PS CS is reported and analyzed as data.

Vincent J. Kopp, MD, FAAP

Department of Anesthesiology

School of Medicine

University of North Carolina at Chapel Hill

Chapel Hill, North Carolina

[email protected]


1. Carvalho AR, Pacheco SA, de Souza Rocha PV, Bergamini BC, Paula LF, Jandre FC, Giannella-Neto A. Detection of tidal recruitment/overdistension in lung-healthy mechanically ventilated patients under general anesthesia. Anesth Analg. 2013;116:677–84
2. Owens WD, Felts JA, Spitznagel EL Jr. ASA physical status classifications: a study of consistency of ratings. Anesthesiology. 1978;49:239–43
3. Aronson WL, McAuliffe MS, Miller K. Variability in the American Society of Anesthesiologists physical status scale. AANA Journal. 2003;71:265–73
4. Higashizawa T, Koga Y. Modified ASA physical status (7 grades) may be more practical in recent use for preoperative risk assessment. Available at: Accessed March 15, 2013
5. Aplin S, Baines D, DE Lima J. Use of the ASA Physical Status Grading System in pediatric practice. Paediatr Anaesth. 2007;17:216–22
6. Mak PHK, Campbell RCH, Irwin MG. The ASA physical status classification: inter-observer consistency. Anaesth Intensive Care. 2002;30:633–40
7. American Society of Anesthesiologists. . ASA Physical Status Classification System. Available at:
8. Lema MJ. Using the ASA physical status classification may be risky business. ASA Newsl. 2002;66:1–3
© 2013 International Anesthesia Research Society