Variability in assignment of ASA grading for obstetric patients
Abstract Number: F-02
Abstract Type: Original Research
In 1941, ASA introduced a six-part ‘fitness for surgery’ grading system(1), which was later developed into the five-part ASA Physical Status Classification in 1961(2). Its application in obstetric anaesthesia has always been point of controversy due to the physiological changes associated with pregnancy(3). ASA grading is used worldwide and is recognised as part of the WHO checklist. We designed and circulated an international survey to anaesthetists and obstetricians in the UK and in the USA aimed to investigate the level of consistency with ASA grading in obstetric population.
A survey was circulated online to several hospitals in UK and USA. Participants were asked to assign an ASA grade to the following cases: A) A 30 year old primiparous woman has no past medical history and takes no regular medicines. In her 34th week of pregnancy she develops high blood pressure, proteinuria, severe headache and visual disturbances; B) A 25 year old multiparous woman has a past medical history of asthma. She normally takes inhalers when needed. She has attended hospital once with her asthma, but has had no HDU or ITU admissions; C) A 23 primiparous woman has no past medical history and takes no regular medicines. She has had no problems in this pregnancy; D) A 40 year old multiparous woman has no past medical history and normally takes no medicines. She is currently on antibiotics for the treatment of an urinary tract infection; E) A 29 year old multiparous woman has had a vaginal delivery. Her estimated blood loss in the room is 1L and she continues to bleed. She is taken to theatre for an exploration. She loses a further 1L and receives 2 units of red blood cells. She is tachycardic and hypotensive.
100 survey responses were collected:90 responders were anaesthetist and 10 obstetricians. 61% of responders were senior anaesthetists and 21% were trainees. Amongst senior anaesthetists, 64% were obstetric anaesthetists. 62% of responders had more than 5 years experience in obstetrics. A great variety in the assignment of ASA grades to different scenarios was observed. The ASA grade assigned to the same scenario varied from 1 to 5 according to different responders.
Our survey showed wide range of variability between clinicians in assigning ASA grades in obstetric patients and reluctance to assign ASA 2 grade to healthy pregnant patients. There was even greater variability in assigning ASA grading to pregnant patients with acute medical problems. These results suggest a need for further education and clarification in the ASA grading system, or a revision of the ASA system itself, including introduction of modifier such as “G”(3) or “P”(4).
1)Saklad M et al.Anesthesiology 1941;2:281-4
2)Dripps RD et al.JAMA 1961;178:261-6
3)Barbeito A et al.Anaesthesiology 2003;99:A-1195
4)Pratt SD. Clinical forum revisited: The “P” value. SOAP newsletter 2003