General Information

  • The Pre-operative exam should focus on the airway along with the cardiovascular and respiratory systems
  • Further examination may be indicated based on patients’ pre-existing co-morbidities

Vital Signs

For preoperative assessments, it is important to have an accurate, up-to-date set of baseline vitals available. Follow the directions for assessing vital signs.

Biometric Measurements

  • Obtain the height and weight and use these measurements to calculate the Body Mass Index (BMI)
    • BMI = weight (kg)/height (meters)2

General Inspection

  • Observe patient’s mental state. Alert, calm, or anxious?
  • Is the patient young or elderly, fit, deconditioned, emaciated or bed-ridden?

Airway Examination

General Inspection

  • Assess the ease of bag-mask ventilation (BMV) using the mneumonic "BONES"
    • Beard: assess for facial hair, which can make securing a seal with the facemask difficult
    • Obesity: may result in upper airway obstruction and difficult BMV in an unconscious patient. In particular, large neck circumference is associated with difficult tracheal intubation
    • No teeth: without teeth, the tongue collapses against the palate of a closed mouth, resulting in obstruction of oxygen flow with BMV
    • Elderly: increased difficulty with BMV in patients >55 years of age
    • Snoring and Stiffness: snoring is a symptom of upper airway obstruction, and is associated with difficult BMV. Diseases that reduce lung compliance are also associated with difficult BMV
  • General inspection should also include looking for obvious facial deformities

TMJ Mobility Assessment

  • With patient in seated position, with their head in neutral position, have them open their mouth as wide as possible.
    • Palpate the space created between the tragus of the ear and the mandibular condyle. It should be approximately one fingerbreadth

Mouth Opening Assessment

  • With the patient sitting up straight with head in neutral positive, assess mouth opening
    • The opening of the patient’s mouth should admit three fingers between the teeth (~5-6cm)
  • At this time, inspect inside the mouth for:
    • Any loose, capped, prominent or missing teeth
    • Dentures or dental bridge appliances
    • Tongue size
  • Use the Modified Mallampati Classification to help determine whether the patient’s airway will be difficult
    • The examiner should face the patient at eye level, and the patient should remain sitting upright with the head in a neutral position
    • Class I: soft palate, uvula, fauces and pillars visible
    • Class II: soft palate, part of uvula, and fauces visible
    • Class III: soft palate and base of uvula visible
    • Class IV: only hard palate
  • When used alone, the Modified Mallampati Classification has limited accuracy for predicting the difficult airway. However, when used with the rest of the airway examination it helps the anesthetist prepare appropriately for airway management

Thyromental Distance Assessment

  • Measure the thyromental distance (TMD) with the patient’s neck in full extension
    • This distance is measured from the lower border of the chin to the thyroid cartilage notch, and should be ≥3 finger breadths (or >6.5cm)

Mandibular Protrusion

  • Ask patient to bring their lower jaw as far forward as possible or to try to bite their upper lip with their bottom teeth
    • Class I: patient is able to protrude lower incisors anterior to upper incisors
    • Class II: patient’s lower incisors can just reach upper incisors
    • Class III: lower incisors cannot protrude to upper incisors. The inability to extend the lower incisors beyond the upper incisors may be indicative of difficult laryngoscopy

Cervical Spine Range of Motion

  • Ask patient to flex and extend the neck. Note any pain or limitations with this movement

Cardiac Physical Exam

  • A focused cardiovascular exam includes blood pressure measurements, precordial exam and examination of the extremities for signs of heart failure and peripheral vascular disease
  • General information on this component of the exam can be found in the cardiac system physical exam section

Respiratory Physical Exam

  • A focused respiratory exam includes auscultation of the lung fields, noting decreased breath sounds, prolonged expiration, rales, wheezes, or rhonchi. Measuring oxygen saturation by oximetry may help stratify risk prior to high-risk surgeries.
  • General information on this component of the exam can be found in the respiratory system physical exam section

Neurological Examination

  • A neurological assessment should be performed in patients with a history of preexisting motor or sensory weakness. Perform a focused neurological assessment on a patient about to have a regional nerve block.
  • General information on this component of the exam can be found in the neurologic physical exam section


  • Samsoon GL, Young JR. Difficult tracheal intubation: a retro- spective study. Anaesthesia 1987;42:487–90
  • Lee A, Fan LTY, Gin T, et al. A systematic review (meta-analysis) of the accuracy of the Mallampati Tests to predict the difficult airway. Anesthesia & Analgesia 2006;102:1867-78
  • Wijeysundera DN, Sweitzer B-J. Preoperative Evaluation. In: Miller RD. Miller’s Anesthesia. 8th ed. Philadelphia: Saunders Elsevier; 2015: 1085-1155
  • Jordi March i Nogué. Mallampati. In: Mallampati Score. Wikipedia website. Accessed on January 7, 2015