Quote from loveanesthesia
Reimbursement is not tied to the ASA Physical Status but the physician conducting the procedure does need to justify why anesthesia is necessary in order for anesthesia to be reimbursed. We also have the patient sign a form indicating that if the anesthesia costs are not reimbursed then the patient is responsible for the costs. Inability to complete the exam because the patient does not cooperate is a reason. We require that the patient return another day so that we can do a proper workup and consent, rather than stepping in after the procedure was attempted with the RN doing the sedation. Sleep apnea, CHF are 2 reasons that are accepted as far as I know.
ASA PS is not defined anywhere, so it can't be applied consistently. There are many studies documenting the variability in assigning a PS to the same patient. It is not used in billing.
From Aetna (which seems to be consistent with other insurances/medicare from what I have read):
Clinical Policy Bulletin: Anesthesia Services for Gastrointestinal Endoscopy
Aetna considers moderate sedation/analgesia, provided by or under the direction of the endoscopist, to be appropriate and adequate for average risk individuals undergoing standard upper or lower endoscopic procedures. Consequently, Aetna considers not medically necessary the attendance of an anesthesiologist or anesthetist for average risk individuals undergoing standard upper or lower endoscopic procedures.
Aetna considers the use of general anesthesia, monitored anesthesia care (MAC) or deep sedation and the attendance of an anesthesiologist or anesthetist medically necessary for upper or lower gastrointestinal endoscopic procedures in individuals with any of the following sedation-related risk factors when requested by the attending physician:
I. Significant medical conditions:
American Society for Anesthesia Physical Status Class P3 to P5
(see appendix); or Pregnancy; or
Children and adolescents (18 years of age or younger); or
Elderly persons (65 years of age or older).
II. Danger of airway compromise:
History of sleep apnea or stridor; or
Persons with dysmorphic facial features, such as Pierre-Robin syndrome or Down
Persons with oral abnormalities, such as small opening (less than 3 cm in adult);
protruding incisors; high arched palate; macroglossia; tonsillar hypertrophy; or a non-
visible uvula; or
Persons with neck abnormalities, such as obesity involving the neck and facial structures,
short neck, limited neck extension, spinal cord instability, decreased hyoid-mental distance (less than 3 cm in adult), neck mass, cervical spine disease or trauma, disorders of cranial nerves IX or X, tracheal deviation, or advanced rheumatoid arthritis; or
Persons with jaw abnormalities, such as micrognathia, retrognathia, trismus, or significant malocclusion; or
Morbid obesity (BMI greater than 40 or BMI greater than 35 with comorbid medical conditions (refractory hypertension, obstructive sleep apnea, coronary heart disease, type 2 diabetes)).
III. Persons with anticipated intolerance of standard sedatives:
Persons with previous problems with anesthesia or sedation; or Dependence on opiates, sedatives, or hypnotics; or
Drug or alcohol abuse.
IV. Situations in which deep sedation or general anesthesia may be required:
Uncooperative or combative persons (e.g., persons with dementia, psychiatric disorders, young children, etc.); or
Complex procedures or invasive therapeutic procedures (e.g., endoscopic retrograde cholangiopancreatography (ERCP), endoscopic ultrasound (EUS), upper gastrointestinal stenting, emergency therapeutic procedures).