Lung Anatomy and Biochemistry & Lung Transplant Vincent Reformato, MD 12/11/2019 

Lung Anatomy 

Respiratory System 

Pharynx  Subdivisions  Nasopharynx  Ends at soft palate  Oropharynx  Extends to epiglottis  Hypopharynx  From epiglottis to level of cricoid cartilage  Innervation  Sensory: glossopharyngeal (IX)  Motor: Pharyngeal branch of Vagus (X)  Except sylopharyngeus – glossopharyngeal (IX) 

Larynx  Innervation  Sensory- Internal branch of superior laryngeal  Motor- Recurrent laryngeal  Exception! Cricothyroid: external branch of superior laryngeal 

Laryngeal Cartilages  Thyroid  Cricoid  Epiglottis  Arytenoids  Cornicuate  Cuneiform 

Intrinsic Laryngeal Muscles  Intrinsic  Cricothyroid  Lenthen and tense vocal cords  Posterior cricoarytenoid  ABduct VC  Lateral cricoarytenoid  Increase medial compression  Transverse arytenoid  ADduct VC  Oblique arytenoid  Constricts distance between arytenoids  Thyroarytenoid  narrows the laryngeal inlet, shortens the vocal folds, and lowers voice pitch 

Extrinsic Laryngeal Muscles  Sternothyroid  Omohyoid  Sternohyoid  Inferior constrictors  Thyrohyoid  Digastric  Stylohyoid  Mylohyoid  Geniohyoid  Hyoglossus  Genioglossus 

Laryngeal Blood Supply  Upper Half  Superior Laryngeal Artery  Branch of Superior Thyroid Artery <- External Carotid  Lower Half  Inferior Laryngeal Artery  Branch of Inferior Thyroid Artery <- Thyrocervical Trunk <-Subclavian 

Vocal Cord Paralysis 

Pediatric vs. Adult Airway  Large tongue  Occiput  Larynx and trachea conical (uncuffed tubes)  Narrowest portion at cricoid  Larynx higher (C4 in peds, C6 in adults)  Vocal cords directed upward in child (horizontal in adults) 

Muscles of Respiration 

Lung Biochemistry 

β-Agonists  Ex. Albuterol, metaproterenol, terbutaline  At bronchial smooth muscle, +cAPM-> -Ca2+ -> muscle relaxation  Β2 selectivity avoids cardiac excitation 

Anticholinergics  Ex. Ipratropium  Quarternary ammonium compounds (do not enter blood stream when inhaled)  Block cGMP production -> less Ach -> low cholinergic tone, less bronchoconstriction 

Steroids  Inhaled (Fluticasone, Budesonide)  Systemic (glucocorticoids)  Increases production of inflammatory mediators, leading to bronchodilation 

Leukotriene Modifiers  Ex Montelukast (Singulair)  Blocks leukotriene D4 in lungs -> no smooth muscle constriction 

Mast Cell Stabilizers  I.e Cromolyn  Blocks histamine release and cytokines for exercise and allergen induced asthma  Possible role in Calcium inhibition 

Immunoglobulin E Blockers  Monoclonal antibodies (omalizumab [Xolair])  Prevent crosslinking of antibodies and downstream effects  Block release of histamine, leukotrienes,tryptase, inflammatory cytokines, 

Lung Transplantation INDICATIONS 1. COPD 2. Interstitial lung disease 3. Cystic Fibrosis 4. Primary pulmonary hypertension 

Contraindications ABSOLUTE  Untreatable dysfunction of another major organ (Heart, liver, kidney)  Malignancy within 2 years  Psychiatric disorder or noncopliant behavior  Substance addiction  Chronic active Hep B or C, or HIV  Significant chest or spinal deformity  Noncurable chronic extrapulmonary infection RELATIVE  Age >65  Unstable condition (shock, ECMO)  Limited functional status  Severe obesity  Severe/symptomatic osteoporosis  Colonization with highly resistant or virulent bacteria, fungi, or mycobacteria 

Lung Transplant Variations  Single Lung  Bilateral Sequential (Double) Lung  Combined Heart-Lung  Living-related Lobar Transplant 

Anesthetic Technique  Double Lumen Ett  Invasive Monitors  A-Line, PA catheter, TEE  +/- CPB  +/- ECMO  Respiratory support  Inhaled Agents for Pulmonary Hypertension  Inhaled Nitric Oxide  Inhaled Epoprostenol 

Double Lumen ETTs  Lets Examine! 

Specific Considerations COPD  Hypotension on induction (positive pressure ventilation) CYSTIC FIBROSIS  Difficult ventilation  Slower Inspiratory phase and high pressures  Thick secretions PULMONARY HYPERTENSION  Hemodynamic collapse on induction  Right heart dysfunction PULMONARY FIBROSIS  Poor tolerance of OLV