Assessing the physical appearance of facial structure is an essential component of the pre-anesthesia evaluation. This assessment helps the anesthesia provider anticipate potential difficulties in airway management and tailor an appropriate plan for anesthesia induction. Here’s how the assessment typically proceeds:
- General Appearance: Begin by observing the patient’s general appearance. Note any abnormalities such as facial asymmetry, deformities, or obvious swelling.
- Facial Symmetry: Assess the symmetry of the face by comparing the right and left sides. Facial asymmetry could indicate underlying conditions such as craniofacial anomalies or trauma.
- Nasal Patency: Evaluate nasal patency by observing for signs of nasal obstruction such as flaring nostrils, nasal congestion, or deviated septum. A clear nasal passage is crucial for maintaining adequate airflow during anesthesia.
- Mouth Opening and TMJ: Measure the interincisor distance, which is the distance between the upper and lower incisors when the mouth is fully opened. Limited mouth opening (trismus) may pose challenges during airway management and intubation. For adults, it’s recommended that the distance between the upper and lower incisors should be at least 3 cm to reduce the risk of laryngoscopic trauma or damage to the teeth. Sufficient mouth opening is essential for the effective placement of various supraglottic airways and other airway adjuncts. Temporomandibular joint (TMJ) mobility refers to the range of motion and flexibility of the jaw joint, which connects the jawbone to the skull. Limited TMJ mobility can hinder proper positioning for intubation and mask ventilation, potentially complicating anesthesia administration.
- Mallampati Score: Perform the Mallampati assessment by asking the patient to open their mouth wide and protrude their tongue without phonation or phonation. This assessment categorizes the visibility of the pharyngeal structures, providing an estimation of potential difficulty in laryngoscopy and intubation.
- Neck Mobility: The assessment of the cervical spine involves several key factors: a: Stability: Begin by evaluating the stability of the cervical spine. This assessment typically starts with assessing the patient’s range of motion. b: Head Mobility and Flexibility: Check the patient’s ability to move their head in all directions. Pay attention to any limitations or discomfort during movement. Also, observe for changes in cerebral perfusion that may occur with cervical extension or flexion. c: Indicators Influencing Airway Management: Look for any signs or indicators that may impact airway management, such as cervical spine abnormalities, previous traumas, fusions, severe arthritis, or other tissue abnormalities. These factors can significantly affect the approach to airway management. d: History of Spine Conditions: Inquire about any history of spine conditions, surgeries, or injuries. Previous spine traumas, fusions, or severe arthritis can pose challenges during airway management.
- Thyromental Distance: Measure the thyromental distance, which is the distance between the thyroid notch and the chin with the head extended and the neck flexed. A short thyromental distance may indicate a difficult laryngoscopy and intubation. A distance greater than three fingerbreadths, roughly 6.5cm, between the mentum and thyroid notch is considered ideal. However, a measurement of less than three fingerbreadths suggests a potentially restricted thyromental space. This limitation could impede the displacement of the tongue during direct laryngoscopy, potentially resulting in challenges in visualizing the glottic opening.
- Hyoid Bone Position: Palpate the hyoid bone, which lies at the level of the base of the mandible. A higher-than-normal hyoid bone position may correlate with difficult laryngoscopy.
- Tongue Size: Assess the size of the tongue relative to the oral cavity. A large tongue may contribute to airway obstruction or difficulty in laryngoscopy.
- Facial Trauma or Pathology: Look for any signs of facial trauma, such as bruising, swelling, or lacerations, as well as any congenital or acquired facial anomalies that may impact airway management.
- Assessment of Dentition: Evaluate the condition of the teeth, including loose or missing teeth, dental prosthetics, or any other oral abnormalities that may affect the insertion of airway devices.
By systematically assessing these aspects of the facial structure, the anesthesia provider can identify potential airway challenges and implement appropriate strategies to ensure safe and effective airway management during anesthesia induction.