In our every-day practice, is there anything more ubiquitous and more time-tested than the ASA physical status (PS) classification system? I don’t think so! From today’s original article by Horvath et al.: “Despite its poor interrater reliability and reproducibility and its limitations as a risk predictor, its simplicity represents its greatest strength as well as its limitation in a world of comprehensive multisystem tools”. In today’s PAAD we’ll review and highlight the recently published review article by Horvath et al. and the revised/adapted pediatric ASA PS classifications by Ferrari et al. This is Jim Fehr’s maiden voyage as a writer/reviewer for the PAAD and is SPA’s representative on the executive council of the PAAD. Jim trained in pediatrics, internal medicine, anesthesiology, pediatric anesthesiology, and pediatric critical care medicine and is Vice President of the Society for Pediatric Anesthesia and the Division Chief of ANESTHESIOLOGY, PERIOPERATIVE AND PAIN MEDICINE at Stanford University. He is one of my mentees and former fellows and I couldn’t be more proud of him! So happy he’s joining us! Myron Yaster MD
Original and Review articles
Balazs Horvath, Benjamin Kloesel, Michael M Todd, Daniel J Cole, Richard C Prielipp. The Evolution, Current Value, and Future of the American Society of Anesthesiologists Physical Status Classification System. Anesthesiology. 2021 Nov 1;135(5):904-919. PMID: 34491303
Ferrari LR, Leahy I, Staffa SJ, Johnson C, Crofton C, Methot C, Berry JG. One Size Does Not Fit All: A Perspective on the American Society of Anesthesiologists Physical Status Classification for Pediatric Patients. Anesth Analg. 2020 Jun;130(6):1685-1692. PMID: 31219919
Ferrari L, Leahy I, Staffa SJ, Berry JG. The Pediatric-Specific American Society of Anesthesiologists Physical Status Score: A Multicenter Study. Anesth Analg. 2021 Mar 1;132(3):807-817. PMID: 32665468
Horavath et al. provide the history of the ASA physical status classification system. “First developed in 1940, the ASA established a committee consisting of Meyer Saklad, Ivan Taylor, and Emery Rovenstine to study, examine, experiment, and devise a system for the collection and tabulation of statistical data in anesthesia.” Interestingly, Saklad published the description of the “physical state” in 1941, the same year that the American Board of Anesthesiology was made a Major Board, and thus severed its affiliation with the American Board of Surgery.1 “In 1961, Dripps et al. published “The Role of Anesthesia in Surgical Mortality.”2 Dripps’ aim was to define the contribution of anesthesia to perioperative deaths. Among the data collected was the patient’s ‘physical status’:”
1. A normal healthy patient
2. A patient with a mild systemic disease
3. A patient with a severe systemic disease that limits activity but is not incapacitating
4. A patient with an incapacitating systemic disease that is a constant threat to life
5. A moribund patient not expected to survive 24 h with or without operation
In the event of emergency operation, the only change in classification was to precede the number with the letter E.
To try to improve interrater reliability and reproducibility3 examples have been developed. I’m going to provide the Pediatric examples recently developed and published by Ferrari et al.4,5
1. Healthy (no acute or chronic disease), normal body mass index percentile for age
2. Asymptomatic congenital cardiac disease, well-controlled dysrhythmias, asthma without exacerbation, well-controlled epilepsy, non-insulin dependent diabetes mellitus, abnormal body mass index percentile for age, mild/moderate OSA, oncologic state in remission, autism with mild limitations.
3. Uncorrected, stable congenital cardiac abnormality, asthma with exacerbation, poorly controlled epilepsy, insulin dependent diabetes mellitus, morbid obesity, malnutrition, severe OSA, oncologic state, renal failure, muscular dystrophy, cystic fibrosis, history of organ transplantation, brain/spinal cord malformation, symptomatic hydrocephalus, premature infant PCA < 60 weeks, autism with severe limitations, metabolic disease, difficult airway, long-term parenteral nutrition, full term infants < 6 weeks.
4. Symptomatic congenital cardiac abnormality, congestive heart failure, sequelae of prematurity, acute hypoxic-ischemic encephalopathy, shock, sepsis, DIC, automatic implantable cardioverter-defibrillator, ventilator dependence, endocrinopathy, severe trauma, severe respiratory distress, advanced oncologic state.
5. Massive trauma, intracranial hemorrhage with mass effect, patient requiring ECMO, respiratory failure or arrest, malignant hypertension, decompensated congestive heart failure, hepatic encephalopathy, ischemic bowel or multiple organ/system dysfunction.
Despite these examples, interrater reliability remains poor. Would printing these examples or incorporating them into our EMRs help? Or should our SPA informatics colleagues develop a specific mobile app that with user input provide more consistent patient classifications? We don’t know, but as Einstein said ““Insanity is doing the same thing over and over and expecting different results.” (see the PS below)
Despite its problems Horvath et al. conclude: “We envision continued utilization of this bedside tool by both anesthesia professionals and others for years to come. Ultimately, its future will be determined by the medical needs of clinicians, the research needs of investigators, the oversight needs of regulators—and most importantly, the goals of the ASA leaders and its membership. In order to stay current and meet these diverse demands, the system warrants periodic re-examination, consistent with its long-standing history. For now, the ASA and its members should be proud of a system that has stood the test of time.”
Myron Yaster MD and Jim Fehr MD
Saklad, M: Grading of Patients for Surgical Procedures. Anesthesiology 2:281-284, May 1941.
Dripps RD, Lamont A, Eckenhoff JE: The role of anesthesia in surgical mortality. JAMA 1961; 178: 261-6
Owens WD, Felts JA, Spitznagel EL Jr. ASA physical status classifications: a study of consistency of ratings. Anesthesiology. 1978 Oct;49(4):239-43.
Ferrari LR, Leahy I, Staffa SJ, Johnson C, Crofton C, Methot C, Berry JG: One Size Does Not Fit All: A Perspective on the American Society of Anesthesiologists Physical Status Classification for Pediatric Patients. Anesth Analg 2020; 130: 1685-1692
Ferrari L, Leahy I, Staffa SJ, Berry JG: The Pediatric-Specific American Society of Anesthesiologists Physical Status Score: A Multicenter Study. Anesth Analg 2021; 132: 807-817
PS Before posting today’s PAAD, I (MY) reached out to Lynne Ferrari (see references 4, 5) to ask her what she thought about adding the ASA physical status examples into the EMR. Her response: “the informatics group at Boston Children’s Hospital is building a tool that predicts an ASA score based on AI and patient specific co-morbidities and then the provider can either accept the predicted ASA PS or input their own.” So a solution may be on the way…stay tuned!
PSS: I (MY) first met Dr. Horvath, the first author of today original article about 20 years ago, when a group of Hopkins faculty including Lynne Maxwell and Charlie Schleien went to Gyor Hungary to teach an Advanced Pediatric Life Support course. Dr. Horvath was a faculty member there at the time. On a field trip to the country side, we met an elderly woman farmer, dressed in black and a babbushka standing by hay stack. My friend Charlie Schleien said, “wow…she looks like the pictures from the old country”…I pointed out to Charlie that we were in the old country…Myron Yaster MD