Airway Anatomy, assessment and Difficult Airway.pptx

This PPT contains detailed anatomy of Airway, airway Assessment and Difficult airway

1. Anatomy of the Airway, Airway Assessment, and Difficult Airway Dr. Vipul Jaiswal / Dr. Farzeen Qureshi Wockhardt Hospital

2. INTRODUCTION * The airway is the pathway for air to enter the lungs, essential for life. * Understanding its anatomy and assessment is crucial for healthcare professionals. * A difficult airway poses a significant challenge in patient care.

3. The Airway system is made of Upper Airway and Lower Airway Upper airways Nose: The nostrils where air enters the body Sinuses: Air passages in the head Pharynx: A tube that connects the mouth and nose to the larynx and esophagus Larynx: Also known as the voice box, this is located in the neck and protects the lower airway Lower airways Trachea: Also known as the windpipe, this is a hollow tube that moves air to the lungs Bronchi: Large tubes that branch off from the trachea and move air to the lungs Bronchioles: Smaller tubes that branch off from the bronchi and move air to the alveoli Alveoli: Tiny sacs in the lungs where oxygen and carbon dioxide are exchanged

4. Blood Supply and Lymphatics of Upper Airway The upper airways receive blood supply from various branches of the external carotid artery and drain into the internal jugular. The naso and oropharynx also receive blood supply from the facial artery branch of the external carotid via the tonsillar artery. The venous drainage of these structures is via the pharyngeal plexus into the internal jugular vein. The lymphatic drainage is through various lymphatic plexuses of the neck surrounding the internal jugular vessels.

5. Blood Supply and Lymphatics of Lower Airway T he lower airways receive blood flow from two sources: the pulmonary circulation and the bronchial circulation. The pulmonary circulation provides blood from the heart for oxygenation through the right and left pulmonary arteries which follow a branching structure similar to that of the airways themselves. This blood returns as oxygenated blood through the pulmonary veins which follow an independently branching structure to return to the right ventricle. Bronchial circulation provides oxygenated blood to the airway structures themselves. These arteries arise independently from the systemic circulation. The two left bronchial arteries emerge from the thoracic aorta; whereas, the right bronchial artery arises either from one of the superior posterior intercostal arteries or a common trunk with the left superior bronchial artery. These provide nutrition and oxygen to tissues as far as the end of the conducting airways where they anastomose with the pulmonary circulation

6. The bronchial veins are only present near the lung hilum which drain blood from the trachea, and bronchi drain into the azygos vein on the right and either the accessory hemiazygos veins or the intercostal vessels on the left. Pulmonary veins drain the more distal circulation where a small amount of deoxygenated blood makes a minimal impact on the saturation of the returning blood. Lymphatic drainage of the lower airways is through the deep lymphatic plexuses of the pulmonary lymphatic plexuses. These drain to the superior and inferior tracheobronchial lymph nodes bilaterally and then to the right and left ducts connecting to the venous angles, usually directly but on the left, this may converge with the thoracic duct first. Paratracheal nodes drain lymph from the trachea directly into the right and left lymphatic ducts.

7. Nerve Supply Innervation of the pharynx is via cranial nerves VII, IX, X, and XII. The larynx is supplied by the vagus (cranial nerve X) by the superior laryngeal branch directly and the clinically important recurrent laryngeal branch. The lower airways receive parasympathetic fibers from the vagus, some of which are afferent sensory nerves that transmit cough sensations from specialized J receptors in the mucosa as well as stretch receptors from the bronchial muscles and inter-alveolar connective tissues. The efferent fibers of the vagus cause broncho-constriction and secretion from the glandular tissues in the airways. The efferent sympathetic fibers cause bronchodilation by inhibiting the activity of the smooth muscles of the airways.

8. CLINICAL SIGNIFICANCE The importance of the upper airway assessment is paramount in both emergency and anesthetic scenarios. The cricoid cartilage is important both as a clinical landmark and also as the only complete cartilage ring within the upper airway used during cricoid pressure maneuvers. The narrowest portion of the upper airway is the cricoid cartilage in children; therefore, cricothyroidotomy is not recommended in children younger than the age of eight. As children grow and mature, the glottic opening becomes the most narrow point in the airway, and therefore, the most likely point of obstruction and allows bypass by the insertion of a cricothyroidotomy airway.

9. The trachea is the most anterior structure of the neck except for where the thyroid covers it. This means that it can be accessed to provide an airway in both emergencies (cricothyroidotomy) and elective procedures (tracheotomy). The trachea should align with the sternal notch. If this alignment deviates, it can indicate a lung or mediastinal pathology. The right, main bronchus is shorter, wider, and vertically aligned, and this means it is the most common site for aspiration, both in a foreign body aspiration and during the occurrence of an aspiration pneumonitis causing right lower lobe consolidation. In clinical assessment of the lower airways, through auscultation and by the presence of "wheezing" as turbulent airflow generates a musical noise, airway narrowing through edema or bronchoconstriction can be detected

10. AIRWAY ASSESSMENT * Purpose: To determine the patency and potential difficulties in managing the airway. * Methods:    * Visual Inspection: Looking for obstructions, deformities, or signs of distress.    * Auscultation: Listening for breath sounds.    * Patient History: Asking about previous airway issues, allergies, or medical conditions.    * Physical Examination: Assessing the Mallampati score, thyromental distance, and neck mobility.

11. MALLAMPATTI CLASSIFICATION * A visual assessment of the oropharynx to predict the difficulty of intubation. * Class I: Visualization of the soft palate, uvula, and pillars. * Class II: Visualization of the soft palate and uvula. * Class III: Visualization of the soft palate base of the uvula. * Class IV: Only the hard palate is visible.

12. THYROMENTAL DISTANCE * The distance between the thyroid cartilage and the mentum (chin). * A shorter distance may indicate a difficult airway.

13. ASSESSMENT OF CERVICAL AND ATLANTOOCCIPITAL JOINT Laryngoscopic view becomes easier when the neck is flexed on the chest by 25-35° and the a-o joint is well extended (85°). This is called the "snif-fing" or the "Magill's position." Assess the first move-ment by asking the patient to touch his manubrium sternii with his chin. If done, this assures neck flexion of 25-30°. Following this, ask the patient to look at the ceiling without raising eyebrows to test the a-o joint function. DELIKAN’s Test

14. ASSESSMENT OF TEMPORO-MANDIBULAR JOINT . Ask the patient to open his mouth wide and place his three fingers (index, middle and ring) in the opening. If done, this is >5 cm and is adequate for direct laryngo-scopy. . Place index finger in front of the tragus and the thumb in front of the lower part of the mastoid process behind the ear. Ask the patient to open his mouth wide. As the condyle of the mandible slides forward, the index finger in front of the tragus can be indented in its space and the thumb-can feel the sliding of the condyle. This sug-gests good sliding function of mandible (subluxation of the lower jaw).

15. ASSESSMENT OF MANDIBULAR SPACE 1) Thyromental distance: This is the distance between the thyroid notch and mental symphysis when the neck is fully extended. 26.5 cm: No problem with laryngoscopy and intu-bation. 6.0-6.5 cm: Without other concomitant anatomical problems, laryngoscopy and intubation are difficult but possible. <60 cm: Laryngoscopy may be impossible

16. 2) Hyomental distance: This is the distance between the mentum and hyoid bone. It is graded as: Grade I : >6.0 cm Grade II : 4.0-6.0 cm Grade III: <4.0 cr Grade III hyomental distane is usually associated with impossible laryngoscopy and intubation. 3) Length of mandible: If used alone, it does not have much predictive value. In addition, assessment using a measuring tape is usually influenced by the rater's er-ror. Nevertheless, a horizontal length of mandible of at least 9 cm should guarantee easy intubation.

17. ASSESSMENT FOR QUALITY OF GLOTTIC OPENING Modified Cormack and Lehane Grading

18. UPPER LIP BITE TEST Class I: Lower incisors can bite the upper lip above the vermilion line. Class II: Lower incisors can bite the upper lip below the vermilion line. Class III: Lower incisors cannot bite the upper lip.

19. DIFFICULT AIRWAY * A clinical situation where a trained healthcare provider experiences difficulty with:    * Face mask ventilation    * Laryngoscopy    * Endotracheal intubation

20. Causes of Difficult Airway * Anatomical Factors: Obesity, short neck, large tongue, receding mandible. * Pathological Factors: Trauma, infection, tumors, congenital abnormalities. * Patient-Related Factors: Previous difficult intubation, sleep apnea, morbid obesity.

21. Management of Difficult Airway * Early Recognition: Anticipate potential difficulties. * Preparation: Have alternative equipment and personnel available. * Techniques: Use appropriate techniques such as:    * Alternative airway devices: Laryngeal mask airway (LMA), video laryngoscope.    * Awake intubation: For anticipated difficult intubation.    * Surgical airway: Cricothyroidotomy or tracheostomy in extreme cases.

22. Laryngeal Mask Airway Video Laryngoscope

23. Cricothyroidectomy Tracheostomy