Basic Principles of Anesthesia

5 components of the Upper Airway:

6 Components of the Lower Airway:

Leads to the nasopharnx Warms and humidifes gases Primary pathway for normal breathing unless there is an obstruction, polyps, or upper respiratory infection Resistance through nasal breathing is almost two times that of mouth breathing

Leads to the oropharnyx Utilized with high flow rates, such as that seen with exercise

Nose and mouth are separated anteriorly and join posteriorly to form this U-shaped fibromuscular structure Extends from posterior aspect of the nose to the level of the cricoid cartilage

3 components of the Pharnyx:

Nasopharnyx

Lies at C2-C3 level Bound superiorly by the soft palate and inferiorly by the epiglottis Opens into the mouth anteriorly through the anterior and posterior tonsillar pillars

Lies posterior to the larynx and leads to the esophagus Bound superiorly by border of epiglottis and inferior border of the cricoid cartilage at C5-C6 Upper esophageal sphincter lies at the lower edge and acts as a barrier to regurgitation in the conscious patient

Lymphoid tissue in the pharynx that is at high risk for bleeding, especially with nasal intubation Made up of: 1. pharnygeal tonsils (adenoids) --located in nasopharynx 2. Palentine tonsils --located in oropharynx 3. Lingual tonsils --located at the base of tongue

Lies at C3-C6 in adults Lies at C2-C4 in infants and children and descends to C4-C5 by age five Serves as an organ of phonation and as a valve to protect lower airways

Extends from epiglottis to lower level of cricoid cartilage and sits at the junction of the airway and the esophagus (C6) attached anteriorly by the epiglottis, posteriorly by the mucous membrane which extends between the arytenoid cartilage and laterally by the aryepiglottic folds (false vocal cords)

Cartilaginous structure held together by ligaments, muscles, cartilages, and 1 bone (hyoid bone) Composed of nine cartilages: 1. Thyroid 2. Cricoid 3. Epiglottic 4. Corniculate (pair) 5. Arytenoid (pair) 6. Cuneiform (pair)

The only full cartilage ring Used to apply pressure during RSI to occlude esophagus Apply 10N in awake patient and increase to 30N with loss of consciousness Minimum pressure of 25mmHg

Sits at the base of the tongue and separates hypopharynx from larynx and hangs over the laryngeal opening Fibrous cartilage with mucous membrane covering that reflects up to the pharnygeal surface of the tongue and makes the glossoepiglottic fold Valleculae sits on either side of fold Protects against aspiration by covering glottis during swallowing