Overall Preoperative Evaluation (Anesthesia Text)


It is important to take a thorough patient history, which includes the following components: History of Present Illness (HPI: the concise history behind the current medical condition leading up to the surgical intervention and what is the specific surgical intervention), Past Medical History (PMH: important to document comorbidities, especially those involving heart, lungs, liver, and kidneys, paying particular attention to hypertension, diabetes, coronary artery disease, reactive airway disease, recent pulmonary infections, and history of stroke or myocardial infarction), Past Surgical History (PSH: type of surgery, type of anesthesia received (regional, monitored anesthetic care (MAC), or general anesthesia), any complications from anesthesia (difficult intubation, prolonged wake up, difficulty with ventilation, post operative nausea and vomiting, etc.), and any prior anesthetic records available for the medical chart), allergies (including specific reaction), current medications (particular attention to the dosages and last administration of blood pressure medications, anti-platelet medications (Aspirin, Plavix), diabetic medications (oral and parenteral) and steroids), Family Medical History (family member having problems with general anesthesia), Social History (tobacco use, alcohol consumption, and illicit drugs), Modified Review of Systems (chest pain, dyspnea, orthopnea, acid reflux symptoms, metabolic equivalents (METS: 2 flights of stairs, walking around a city block)), and laboratory values and recent studies (basic chemistry panel including calcium and magnesium, CBC with platelets, PT/PTT/INR, 12 lead EKG, chest x-ray, stress test within last 5 years, echocardiogram, and coronary catheterization report).

In addition to the medical history, it is important to do a focused physical exam (vitals, weight (in kilograms), IV access, mental status, cardiovascular exam, pulmonary auscultation, airway assessment with Mallampati score, dentition, range of motion of neck, and TMJ).

Also talking to patients about their particular wishes is important, especially after reviewing the type of anesthetic options available and the risks, benefits, and alternatives of each treatment option. Equally important to safety of delivered anesthetic is to realize the patients fears and concerns (i.e. an anesthetic plan for regional block with light sedation may be acceptable from a surgical perspective, but if the patient fears recall and prefers not to be awake and conscious during the operation, then such wishes must be honored as long as the patients safety is not jeopardized).

Common Home Medications Which Affect Anesthesia
Drug Effect
ETOH Tolerance to anesthesia
B-blockers Bronchospasm
ABx Prolongation of NMJ blockade
Benzos Tolerance to anesthesia
Diuretics Hypovolemia, hypokalemia


Physical Exam

The focused physical exam should include :

  • General
    • BMI
    • jaundice
  • Airway
    • Mallampati score/mouth opening
    • cervical spine mobility
    • temporomandibular joint mobility
    • teeth (especially diseased/loose/artificial)
    • thyromental distance
  • Pulmonary
    • auscultation
    • thoracic shape and expansion
    • oxygen saturation on room air
  • CV system
    • auscultation for murmurs
    • pulses
    • venous access sites
    • edema
    • venous pressure
    • BP (including postural drop if relevant)/heart rate/rhythm
  • CNS
    • motor & sensory function
    • cognitive function
  • Hematologic
    • petechiae
    • bruising
    • clinical evidence of anemia

Routine Labs and Testing

Patients who are in optimal living conditions and who are undergoing a procedure with minimal risks do not need preoperative labs [Roizen (eds): Advances in Anesthesia p25-43, 1993].

In the past EKG has been recommended at 40 years of age for men for all general anesthetics (women at 50). However, recent data suggests this will lead to considerable over-testing. Thus in “Preoperative Electrocardiograms, Patient Factors Predictive of Abnormalities” (Anesthesiology 2009; 110:1217–22) a total of 1,149 electrocardiograms were reviewed, with 89 patients (7.8%) having at least one significant abnormality. Patients at higher risk of having significantly abnormal electrocardiograms which would potentially affect management were those older than 65 yr of age or who had a history of heart failure, high cholesterol, angina, myocardial infarction, or severe valvular disease. Five patients (0.44%) had an abnormal electrocardiograms in the absence of risk factors. Operative factors in considering ECG and other tests include the type of surgery, the expected blood and fluid shifts, and the operative duration should influence the pre-operative tests required.

The United Kingdom National Institute for Health and Clinical Excellence (NICE) issued a guideline on this topic in 2003 based on a systematic review of the literature, and this guidance can be found here. This is a complex and nuanced guideline which emphasizes comorbidities and concurrent illness in considering testing and looks broadly at testing including renal function and blood gases.

In addition to the issue of routine testing, current attempts to improve cardiac outcomes may have led to excessive use of invasive cardiac evaluation. Thus, “These results confirm that most patients, even high-risk patients who are undergoing high-risk surgery, will have similar outcomes regardless of whether or not they undergo invasive procedures beforehand. Such procedures should be performed only in patients with unstable ischemic coronary disease.” (J Watch, General Medicine June 15, 2009, p 97, on Am J Cardiol 2009, Apr 1; 103:897.) A detailed recent guideline by the American College of Cardiology indicating the full complexity of the issue can be found here.


Age General Anesthesia MAC/Regional Anesthesia Nerve Block
< 40 Female: Hb/Hct? Preg. test? None None
40 – 49 Male: ECG, Female: Hb/Hct? Preg. test? None None
50-64 Hb or Hct, ECG Hb or Hct None
65-74 Hb or Hct, ECG, BUN/Creat, Gluc Hb or Hct, ECG Hb or Hct
> 74 Hb+Hct, ECG, BUN/Creat, Gluc, CXR? Hb+Hct, ECG, BUN/Creat, Gluc Hb+Hct, ECG

Note: It is not clear that the distinctions in testing by type of anesthesia rather than patient medical condition (H&P) and the stressfulness of the procedure is warranted.

Overall Risks

0.2% risk of death within 48 hours for ALL operations, due to anesthesia in 0.01% of procedures [Miller (ed.), p 893-927, 2005]. Emergency and vascular surgery are associated with increased risk [Am Soc Anesth: New Class. of Phys Stat 24: 111, 1964] as are procedures with large blood loss or fluid shifts, with risk of death approaching 5% for certain procedures [Miller]. ASA status, for all its shortcomings, does well as a predictor of outcome [Am Soc Anesth: New Class. of Phys Stat 24: 111, 1964].

ASA Status

ASA Class Description
1 Healthy
2 Mild to moderate systemic disease
3 Severe systemic disease
4 Severe systemic disease which is constant threat to life
5 Moribund patient
6 Brain-dead donor
E Appended for emergency surgery e.g. ASA 2E