What are the Physical Status Classifications for a Pre-Anesthesia Evaluation?

Patient Presentation
A 3-year-old female comes to clinic for a pre-anesthesia evaluation. She has some mild cognitive delay for which she is receiving special services. She has extensive dental caries which will require general anesthesia and she is otherwise healthy.
The past medical history reveals no previous hospitalizations, surgeries or sedation.
The family history is negative including no malignant hyperthermia or other problems related to anesthesia.
The review of systems is normal including no recent colds or fevers, bruising or bleeding, sleep problems or snoring.
The pertinent physical exam reveals a cooperative child with normal vital signs. She acts like a child between 2 to 2.5 years of age. Her pulse oximetery is 98% on room air. Her nares are patent bilaterally. She has no obvious facial anomalies.
Her pharynx is clear with the uvula easily seen and tonsils slightly enlarged to just beyond the tonsilar pillars.
Her tongue is not enlarged. She has extensive dental caries with no broken or capped teeth. Her normal-sized neck is supple. Her heart, lungs, and rest of her examination is normal.
The diagnosis of mild cognitive delay and extensive dental caries was confirmed. On physical examination her airway is assessed as American Society of Anesthesiologists (ASA) Class I and her physical status is also Class I. The physician reported to the family, dentist and anesthesiologist that she had no obvious contraindications to general anesthesia at the time he saw the patient. However,
he reminded the family to report any changes to the child’s health to the dentist and anesthesiologist prior to her having the procedure.

Pediatric healthcare providers are often asked to evaluate a child for risks for anesthesia for emergent and non-emergent procedures such as laceration repairs, setting fractures, endoscopy, computed tomography or magnetic resonance imaging procedures, or operating room procedures.
The provider must perform a careful history and physical examination, assign the ASA status and may or may not document a sedation plan.

The history should focus on identifying risk factors that may increase the sensitivity to sedatives or analgesic medications, patients at risk of cardiopulmonary complications or difficulties in managing complications if they were to arise.

  • Underlying cardiopulmonary disease may cause accentuated depression with sedatives and analgesics
  • Renal and hepatic disease may impair drug metabolism
  • Other medications may cause untoward drug interactions
  • Allergies may cause allergic reactions
  • Alcohol or substance abuse drugs may change the patient’s reaction to the sedatives and analgesics
  • Tobacco may cause airway irritability, bronchospasm and coughing
  • Previous reactions to anesthesia may increase the risk in subsequent procedures
  • Airway history that increases the sedation risk includes stridor, snoring, sleep apnea, dysmorphic facial features, Down Syndrome, upper respiratory infections, and advanced rheumatoid arthritis

The physical examination should be through but the cardiac, respiratory and airway are emphasized.

    Normal Airway Examination

    • Opens mouth normally (for adults – greater than 2 finger widths or 3 cm, children vary by age)
    • Able to see at least part of the uvula and tonsillar pillars with mouth wide open & tongue out
    • Normal chin length (for adults – length of chin is greater than 2 finger widths or 3 cm, children vary by age)
    • Normal neck flexion and extension without pain/paresthesias
    Abnormal Airway Exam

    • Inability to open mouth normally
    • Inability to visualize at least part of uvula or tonsils with mouth open and tongue out
    • High arched palate
    • Tonsillar hypertrophy
    • Small or recessed chin
    • Neck has limited range of motion
    • Low set ears
    • Signficant obesity of the face/neck

Figure 18 shows the ASA airway classification. The progression of diagrams from left to right suggests increased difficulty in airway management during sedation.

Patients with any significant history or an abnormal airway examination (including Class III or IV airway) should be considered at higher risk and should be evaluated by anesthesia personnel.

Relative to older children or adults, infants and small children are/have:

  • Obligate nose breathers
  • Disproportionately large heads
  • Comparatively large tongues and hypopharyngeal structures
  • Small tracheas
  • Increased oxygen consumption
  • Relatively nondistensible heart ventricles that respond less well to increases in preload
  • Need to maintain heart rate to maintain cardiac output
  • At risk of bradycardia with physiologic stress because the parasympathetic nervous system is the dominant component of the autonomic nervous system therefore they respond to stress with bradycardia. The opposite is true in older children or adults as the sympathetic nervous system dominates.
  • Immature temperature regulation

Patients may have a pre-operative evaluation that is normal but experience other changes to their health between the time of the pre-operative evaluation and the procedure. Patients and families need to report any changes to the health care providers who will be doing the procedure and providing the anesthesia.

Learning Point

The ASA patient classification for physical status is:

  • Class I – A normal, healthy patient. The pathological process for which surgery is to be performed is localized and does not entail a systemic disease (ex. a healthy patient for a dental procedure).
  • Class II – A patient with systemic disease, caused either by the condition to be treated or other pathophysiological process, but which does not result in limitation of activity (ex. a patient with asthma that is controlled with intermittant inhaler use and has no systemic sequelae).
  • Class III – A patient with moderate or severe systemic disease caused either by the condition to be treated surgically or other pathophysiological processes, which does limit activity (ex. patient with uncontrolled asthma that limits activity).
  • Class IV – A patient with severe systemic disease that is a constant potential threat to life (ex. a patient with renal failure requiring dialysis).
  • Class V – A patient who is at substantial risk of death within 24 hours, and is submitted to the procedure in desperation (ex. a patient in respiratory failure despite treatment who is being placed on ECMO).

The modifier “E” is added if the procedure is being done emergently (ex. a healthy patient having a tibia fracture set would be classified as ASA IE.)

The child in this case was classified as a ASA Class 1 physical status. She was healthy and had what appears to be a static mild cognitive delay.

Questions for Further Discussion
1. What medications are commonly used for conscious sedation for pediatric procedures?
2. What are the definitions of various sedation levels?
3. What are the risk factors for malignant hyperthermia and how is it treated?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

To view current news articles on this topic check Google News.

Task Force on Preanesthesia Evaluation. Practice Advisory for Preanesthesia Evaluation: A Report by the American Society of Anesthesiologists Task Force on Preanesthesia Evaluation. Anesthesiology. 2002:96(2);485-49.
Available from the Internet at http://www.anesthesiology.org/pt/re/anes/fulltext.00000542-200202000-00037.htm;jsessionid=Ckip1VK1V1itKJUK4S9VBzIvmgmB95sZ2te1Z3RsWytUKnPpUZ9u!-1232483647!-949856032!9001!-1 (rev. 3/2004, cited 6/6/05).

Hara T, Nickel EJ, Hindman B. Morgan D. Procedural Sedation Resource Center: Guidelines, Education, and Testing for Procedural Sedation and Analgesia.
Available from the Internet at http://www.vh.org/adult/provider/anesthesia/ProceduralSedation/index.html (rev. 3/2004, cited 6/6/05).

Donna M. D’Alessandro, MD
Associate Professor of Pediatrics, Children’s Hospital of Iowa

August 1, 2005