Airway Management & Ventilation 1 PDF

The Institution of Excellence in Technical and Vocational Education and Training www.udst.edu.qa HSPA 2111 Airway Management and Ventilation Anatomy Physiology Airway assessment Oxygen administration Airway adjuncts This week in 2111… Airway...

The Institution of Excellence in Technical and Vocational Education and Training www.udst.edu.qa HSPA 2111 Airway Management and Ventilation Anatomy Physiology Airway assessment Oxygen administration Airway adjuncts This week in 2111… Airway Management & Ventilation Lecture Skill review and continued practice [OPA, NPA & Suctioning] Quiz #1 30 September 2:00 – 3:00 Function of the Respiratory System Brings in oxygen Eliminates carbon dioxide If interrupted, vital organs will not function properly Brain can survive for only 6 minutes or so without oxygen before permanent brain damage. Airway Anatomy – Upper Airway Location Function Pharynx (throat) Nasopharynx Inhalation Nasal cavity Trauma to the nasal cavity Turbinates Sinuses Nasal septum Oropharynx Forms the posterior portion of the oral cavity Bordered superiorly by the hard and soft palates, laterally by the cheeks, and inferiorly by the tongue 32 adult teeth Significant force is required to dislodge teeth  Oropharynx Tongue Large muscle attached to the mandible and hyoid bone Hyoid bone: small, horseshoe- shaped bone to which the jaw, epiglottis, and thyroid cartilage also attach Tongue has the tendency to fall back and occlude the posterior pharynx when the mandible relaxes. Oropharynx Palate Forms the roof of the mouth Separates the oropharynx and nasopharynx Hard palate: Anterior portion formed by the maxilla and palatine bones Soft palate: Posterior to the hard palate Adenoids Located on the posterior nasopharyngeal wall Lymphatic tissues that filter bacteria Tonsils: located in the posterior pharynx; help trap bacteria Adenoids and tonsils often become swollen and infected. Severe swelling of the tonsils can cause obstruction of the upper airway Oropharynx Uvula Soft-tissue structure Resembles a punching bag Located in the posterior aspect of the oral cavity, hanging just above the base of the tongue Epiglottis Superior border of the glottic opening Leaf-shaped cartilaginous flap Prevents food and liquid from entering the larynx during swallowing Vallecula Anatomic space or “pocket” Located between the base of the tongue and the epiglottis Important landmark for tracheal intubation Larynx Complex structure Formed by many independent cartilaginous structures Marks where the upper airway ends and the lower airway begins Thyroid cartilage Shield-shaped structure Formed by two plates that join in a V shape anteriorly Form the laryngeal prominence known as the Adam’s apple Suspended in place by the thyroid ligament Directly anterior to the glottic opening Larynx Cricoid cartilage (or cricoid ring) Lies inferiorly to the thyroid cartilage Forms the lowest portion of the larynx First ring of the trachea Only upper airway structure that forms a complete ring Cricothyroid membrane Between the thyroid and cricoid cartilages Site for emergency surgical and nonsurgical access to the airway Bordered laterally and inferiorly by the highly vascular thyroid gland You must locate the anatomic landmarks carefully when accessing the airway via this site. Larynx Glottis (or glottic opening) Space in between the vocal cords and the narrowest portion of the adult’s airway Airway patency is heavily dependent on adequate muscle tone. Vocal cords: lateral border of glottis; white bands of tough tissue partially separated at rest. During forceful inhalation, vocal cords open widely to provide minimum resistance to air flow. Larynx Laryngospasm Spasmodic closure of the vocal cords, which causes a partial or complete airway obstruction Reflex normally lasts a few seconds If persistent, can threaten the airway by preventing ventilation altogether Anatomy of the Lower Airway Function Exchanges oxygen and carbon dioxide Location Externally, it extends from the fourth cervical vertebra to the xiphoid process. Internally, it spans the glottis to the pulmonary capillary membrane. Anatomy of the Lower Airway Trachea Windpipe Conduit for air entry into the lungs Tubular structure Approximately 10 to 12 cm in length and consists of a series of C-shaped cartilaginous rings Begins immediately below the cricoid cartilage Descends anteriorly down the midline of the neck and chest to the level of the fifth or sixth thoracic vertebra Divides into the right and left main stem bronchi at the level of the carina  Anatomy of the Lower Airway Right bronchus Somewhat shorter and straighter than the left bronchus A tracheal tube inserted too far will often come to lie in the right main Hilum All of the blood vessels and the bronchi enter each lung at this spot. Lungs consist of the entire mass of tissue that includes the smaller bronchi, bronchioles, and alveoli. Anatomy of the Lower Airway Lungs Right lung has three lobes. Left lung has two lobes. Covered with a thin, slippery outer lining (visceral pleura) Parietal pleura: lines the inside of the thoracic cavity Small amount of fluid is found between the pleurae (decreases friction during breathing).  Anatomy of the Lower Airway Bronchus Divides into increasingly smaller bronchi Bronchioles: made of smooth muscle; dilate or constrict in response to various stimuli Smaller bronchioles branch into alveolar ducts that end at the alveola Alveoli Balloon-like clusters of single-layer air sacs Functional site for the exchange of oxygen and carbon dioxide exchange by simple diffusion between the alveoli and the pulmonary capillaries Surfactant: proteinaceous substance lining the alveoli; decreases surface tension and keeps them expanded Atelectasis: collapse of the alveoli Special Considerations: Anatomic Differences in the Child Pediatric Airway Differences Head and neck Nose breathers Epiglottis Cricoid cartilage Airway obstruction Geriatric Airway Differences Teeth – dentures Lessened airway and gag reflex Kyphosis Physiology of the Respiratory System The Respiratory Process Ventialtion – the process of moving air in and out of the lungs. Diffusion – oxygen moves from the aveoli to the bloodstream Perfusion – delivery of oxygen and nutrients to the tissues and organs by the circulatory system and removal of waste from the cells, organs and tissues  What is Breathing? Ventilation: The process of moving air in and out of the lungs Inspiration: (inhalation) The process of moving air into the lungs. Expiration: (exhalation) The process of moving air out of the lungs. The Respiratory Cycle A Respiratory Cycle is made up of one inspiration and one expiration. Inspiration: one third of the ventilation cycle Expiration: two thirds of the ventilation cycle Normal I:E Ratio is 1:2 A key component to understanding how we breathe is to understand Boyle’s Law regarding volume and pressure. Inhalation: This is an active process. Diaphragm contracts and flattens. The intercostal muscle contract as well. Chest cavity expands downwards and outwards, increasing the volume of the chest cavity and lungs. This increase in volume causes a decreases in pressure in the lungs, making it a lower pressure then outside the body. Air moves into the lungs (inhalation). Exhalation: This is a passive process. Diaphragm and intercostal muscles relax. This decreases the volume in the chest cavity and lungs. The decrease in volume causes an increase in pressure in the lungs, making it a higher pressure then outside the body. Air moves out of the lungs (exhalation). Respiration The process of exchanging oxygen and carbon dioxide Every living cell needs an uninterrupted supply of oxygen to carry out respiration. Metabolic processes that consume oxygen produce carbon dioxide that must be carried away and disposed of. External respiration (pulmonary respiration) Internal respiration (cellular respiration) Respiration… Diffusion Gas exchange in the body Process in which a gas moves from an area of higher concentration to an area of lower concentration Dissolved oxygen crosses the pulmonary capillary membrane and binds to the hemoglobin molecule of the red blood cell. Approximately 97% of the body’s total oxygen is bound to hemoglobin. Pulse oximetry measures the percentage of hemoglobin that is saturated with oxygen. Carbon dioxide is transported in the blood in the form of bicarbonate ions. Internal and External Respiration Regulation of Ventilation Body’s need for oxygen Dynamic Constantly changing Respiratory system must be able to accommodate those changes by altering the rate and depth of ventilation. Primarily regulated by the pH of the CSF Complex series of receptors and feedback loops that sense gas concentrations in the body fluids and send messages to the respiratory centre in the brain. Regulation of Ventilation cont. Neural control of ventilation Traced to the medulla Involuntary control of breathing originates in the brainstem (pons and medulla) Impulses descend through the spinal cord and can be overridden by voluntary control. Two types of motor nerves affect breathing: Phrenic nerve Intercostal nerve Respiratory rhythmicity center Hering-Breur reflex Apneustic center Pneumotaxic center Regulation of Ventilation cont. Chemical control of ventilation Chemoreceptors Carbon dioxide content monitors Central chemoreceptors Increase in acidity of the CSF causes increased rate and depth of breathing. Primary respiratory drive Hypoxic drive Regulation of Ventilation cont. Control of ventilation by other factors Body temperature Medications Hypoxia Acidosis Metabolic rate Tidal Volume VT Measure of the depth of breathing Volume of air that is inhaled or exhaled during a single respiratory cycle In average adult man: 5 to 7 mL/kg In infants and children: 6 to 8 mL/kg Inspiratory reserve volume: amount of air that can be inhaled in addition to the normal tidal volume (3,000 mL) In the adult, approximately one-third of the normal tidal volume remains in the upper airway passages. Dead space: any portion of the airway where air lingers, but does not contain air and therefore cannot participate in gas exchange Anatomic dead space: includes the trachea and larger bronchi, where residual gas may remain at the end of inhalation; approximately 150 mL in adult male Physiologic dead space: areas created by intrapulmonary obstructions or atelectasis Alveolar Volume Remaining volume of inhaled air Reaches the alveoli and participates in gas exchange Equal to tidal volume minus dead space volume Approximately 350 mL in adult male Minute Volume VM Amount of air that moves in and out of the respiratory tract per minute Minute alveolar volume is the amount of air that actually reaches the alveoli per minute and participates in gas exchange; determined by multiplying the tidal volume (minus dead space volume) by the respiratory rate Will increase if the tidal volume, the respiratory rate, or both increases Will decrease if the tidal volume, the respiratory rate, or both decreases As respirations become faster, they often become more shallow. Functual Residual Capacity Amount of air that can be forced from the lungs in a single exhalation Expiratory reserve volume: amount of air that is exhaled following normal exhalation; approximately 1,200 mL Residual volume: air that remains in the lungs after maximal exhalation; also approximately 1,200 mL in average adult male Fraction of Inspired Oxygen (FiO2) The percentage of oxygen in inhaled air Increases when supplemental oxygen is given to a patient Commonly documented as a decimal point