ADVANCED ASSESSMENT Respiratory System ONTARIO BASE HOSPITAL GROUP QUIT BASE HOSPITAL GROUP ADVANCED ASSESSMENT Respiratory System Instructor Notes by: Rob Theriault EMCA, RCT(Adv.), CCP(F) Donna L.Smith AEMCA, ACP 2007 Ontario Base Hospital Group

ADVANCED ASSESSMENT Respiratory System AUTHOR(S) Mike Muir AEMCA, ACP, BHSc Paramedic Program Manager Grey-Bruce-Huron Paramedic Base Hospital Grey Bruce Health Services, Owen Sound Kevin McNab AEMCA, ACP Quality Assurance Manager Huron County EMS References- Emergency Medicine REVIEWERS/CONTRIBUTORS Rob Theriault EMCA, RCT(Adv.), CCP(F) Peel Region Base Hospital Donna L. Smith AEMCA,ACP Hamilton Base Hospital 2007 Ontario Base Hospital Group

Respiratory System CONSISTS OF: Upper Respiratory Tract   CONSISTS OF: Upper Respiratory Tract Lower Respiratory Tract Instructor Notes: Discuss anatomical dead space vs. gas exchanging regions

Functions Route for air exchange Warms and moistens air Traps/filters particles (nares) Supply of oxygen Removal of carbon dioxide Removal of other wastes Instructor Notes: Tie in the relevance of IV therapy for patients requiring hydration because of problems with tenacious mucous in the lungs (e.g. asthmatics, COPD, etc) Add however that this is a long term goal in the hospital setting and that in most cases, IV therapy is not indicated for mild to moderate asthma exacerbations.

Upper Respiratory Tract Nasal Cavity and Sinuses Pharynx Larynx Trachea Instructor Notes: May be worth introducing concept of Sellick Maneuver on this slide. BURP – Back, UP, Right, Pressure – Pressure on the Adam’s Apple used in Intubation to align axis from mouth to Vocal cords.

Upper Respiratory Tract Purpose Warms Moistens Filters Conveys air to the lower Respiratory Tract What about an intubated patient? Instructor Notes: Discuss the consequences of intubation to the air passages and lungs – e.g. dry O2 delivered, mechanisms for moistening air, clearing particles (nares), etc. bypassed when an ETT is in place.

Upper Respiratory Tract Nasal Cavity Instructor Notes: Consider mentioning the turbinates as this is a good illustration - risk of epistaxis with insertion of nasal ETT (less likely with nasopharyngeal airway). Describe how the floor of the nose is flat/straight and this is why we insert either a nasopharyngeal or nasotracheal tube straight in – as opposed to upward and along the inner curvature of the nose. Describe the cribiform plate and the risk associated with inserting an airway of other device in the nare in the presence of a facial smash.

Upper Respiratory Tract Nasal Sinuses Instructor Notes:

Upper Respiratory Tract Pharynx Instructor Notes:

Upper Respiratory Tract Larynx Level C3-> C6 Extends from hyoid bone to lower border of cricoid (made up of cartilage, joined by ligaments, lined with mucous membrane) 4 Major Cartilages Epiglottis, Thyroid, Arytenoid, Cricoid Instructor Notes: touch on the Sellick maneuver here again from the different anatomical view Describe tracheal rings – i.e. semi-lunar shape & vulnerability for A/E obstruction caused by large FBO in esophagus; especially in children. The rings are open in the back, therefore an obstruction in the esophagus can actually impede the trachea, if large enough.

Upper Respiratory Tract Trachea C6 To T5 From Cricoid to Carina (10cm) First ring only solid one of trachea 16-20 horseshoe shaped cartilages Ciliated columnar epithelium Bifurcates at carina Instructor Notes: consider adding a clinical caveat (verbal) about the cough reflex centre at the carina and the expected response to deep suctioning when PCP works with an ACP. The cough reflex is refered to as the “Honey Spot” when nasally intubating, as it is one of the best indicators that you are sitting at the cords with the tube.

Upper Respiratory Tract Trachea Instructor Notes:

Lower Respiratory Tract Right and Left main stem bronchi Secondary Bronchi Tertiary Bronchi Bronchioles Terminal Bronchioles Respiratory Bronchioles Alveolar Ducts Alveolar Sacs Alveoli Instructor Notes:

Lower Respiratory Tract Bronchial Tree Right Mainstem 5 cm long/ large caliber Shorter more vertical (25 degree angle) Foreign body obstruction Left Mainstem Longer than 5 cm 45 degree angle Instructor Notes: discuss incidence of right Mainstem intubation and the reason why it is important to correct. If intubation tube is passed into the Right Mainstem Bronchus and into the lung and left there, there will be No ventilation into the left lung, therefore compromising the patients outcome due to hypoxia, from hypoventilation.

Lower Respiratory Tract Alveolus Instructor Notes: describe the risk of IV fluid therapy - i.e. increased hydrostatic pressure can lead to fluid movement into the alveoli describe the size of the surface area across which oxygen diffuses (70 square meter) and that we can provide interventions that help to reverse conditions that diminish the size of the area of diffusion - e.g. ventilation for patients with pulmonary edema, ventolin for bronchospasm, ventilation of respiratory depression in overdose, etc.

Lungs Lobes Right Upper Lobe Left Upper Lobe Right Middle Lobe Instructor Notes: discuss aucultation technique and rationale – if patient has considerable adipose tissue in chest region, consider going to the back as you may be able to auscultate breath sounds much easier. You will also be able to get a better look at the patients respiratory efforts. add that A/E may appear to be diminished at the right base compared to the left and this is because, although not depicted well in this diagram, the liver raises the right hemidiaphragm. Left Lower Lobe Right Lower Lobe

Lungs Pleura Instructor Notes: Vertebrae Bronchus Lungs Visceral Pleura Parietal Pleura Heart Instructor Notes: Pleura, the sack that protects the lung tissue from other organs, bony structures ( Ribs)

Lungs Thoracic Cavity Instructor Notes:

Mechanics of Ventilation Pressure Gradient Alveolar  Atmosphere Atmosphere  Alveolar Instructor Notes:

Mechanics of Ventilation Inspiration  Thoracic Cage  3 mmHg Alveolar Pressure Exhalation  Thoracic Cage Passive Process Instructor Notes: The diaphram is the most important muscle in the respiratory cycle. On inspiration, the diaphragm contracts and drops down causing a vacuum which makes the chest expand and causes air to rush in. In Expiration, the diaphragm relaxes again and moves back up therefore pushing air out of the lungs. In knowing this concept, we now have a better understanding of why people in respiratory distress must be assessed completely… Look test included…we can assess how hard they are working to breath, which should be a passive function, instead of a Working process! Note muscle use, position they are sitting in, ability to speak ( # of Words), anxiety level…

Mechanics of Ventilation Accessory Muscles Inspiration Sternocleidomastoids Scalenes Trapezius Exhalation Internal Intercostals Abdominals Instructor Notes: May be worth reinforcing the importance of looking up the signs and symptoms and precipitating factors in the history and physical appearance for COPD as many patients with COPD are aware that they have some sort of lung disease but unaware that it’s a COPD.

Amount of pressure required to expand the lungs Pulmonary Compliance Amount of pressure required to expand the lungs Decrease Compliance Increased Compliance Instructor Notes: Compliance refers to the ability for the lungs to expand to let all of the air in that is coming in… decreased compliance = COPD, any lung disease where lung tissue has been destroyed.

Pulmonary Compliance Surface Tension pressure exerted on alveolus due to cohesive forces of water molecules What stops the lungs from collapsing? Instructor Notes: Discuss how surfactant is analogous to detergent – e.g. if you place your have in a sink full of water and shake it vigorously, bubbles will form and quickly burst as the surface tension in water bubbles is high. If you add detergent (analogous to surfactant), the water tension decreases significantly. Hence the reason bubbles remain expanded much longer Consider discussing RDS in premature newborns from the lack of surfactant (I.e. mechanism of alveolar collapse and fluid movement into the lower airways) Discuss the negative pressure within the alveolus which has a suctioning effect and tends to draw fluid toward itself. This suction-like effect is offset by the greater Oncotic pressure within the pulmonary vasculature which tends to keep fluid within the vessels. Tie in the concept that IV therapy can increase hydrostatic pressure within the lungs to the point that exceeds Oncotic pressure resulting in fluid seepage into the pulmonary interstitium and eventually the alveoli

Mechanical Work of Breathing Key Terms Tidal Volume (TV or VT) Functional Residual Capacity (FRC) Total Lung Capacity Forced Vital Capacity 02 Consumption Normal Breathing – 5% Severe States – 25% Instructor Notes: Describe the term “Functional Residual Capacity” and tie it into the risk of auto-PEEP when assisted ventilation doesn’t allow for sufficient exhalation Auto Peeping refers to putting increased resistance on expired gases, by purse lipped breathing…this actually helps to keep the alveoli open for the next breath… these patients usually have Emphysema – Bad lung tissue… sticky and once the alveoli become too sticky with excess mucos, harder to expand when allowed to collapse completely.

Central Nervous System Control Chemo Receptors                   Central Peripheral Instructor Notes: Discuss sensitivity to high CO2 levels Discuss desensitization to CO2 with chronic CO2 retainers Discuss hypoxic drive

Ventilation Perfusion Ratio Ventilation (V): amount of air that moves in or out of the mouth Minute Ventilation: # of breaths/min X volume of each breath 12 breaths/min x 500ml = 6000 ml (6L) Perfusion (Q): Flow of blood through lungs lungs are perfused with 6L blood per min V = 6L Ventilation = 1 Q 6L Perfusion Instructor Notes: Discuss concept that V/Q is never a perfect “1” With each breath, the ratio between ventilation and perfusion change. These changes are in reaction to changes within the body from breath to breath depending on the demands put on the body at any given moment…anything that affects this balance(disease,exercise,illness…) will alter the ventilation perfusion ratio. This will be discussed again in Oxygenation presentation.

V/Q Mismatch V/Q < 1 = decreased ventilation  V = Asthma, COPD, pulmonary edema or any other condition that interferes with the movement of air to the gas exchanging areas of the lungs V/Q > 1 = absence or    in perfusion in areas of the lungs  Q = Pulmonary Embolism, any shock state where the lungs are significantly hypoperfused Instructor Notes: In a decreased ventilation state – there is not enough air getting in to the alveoli…therefore upsetting the balance. In a decreased perfusion state - there has been an interruption in the transport system to get the oxygen away from the lung tissue and to the body(bleeding,shock…)

V/Q Ratios V/Q = 1 V/Q > 1 V/Q <1 Respiratory Volume = 6 l/m Blood Flow = 6 l/m V/Q = 1 Respiratory Volume < 6 l/m Respiratory Volume = 6 l/m Instructor Notes: Blood Flow = 6 l/m Blood Flow < 6 l/m V/Q > 1 V/Q <1

Instructor Notes:

Intrapulmonary Shunting Area of lung with decreased ventilation (V/Q < 1) will not have fully saturated hemoglobin ex. Hb 75% saturated. This blood will mix with blood that is fully saturated ex. 98%. Mixing of this blood is the shunt Outcome is circulated blood being sat of 88.5 % Instructor Notes:

Oxygen Transport 1.5 % O2 Dissolved in blood plasma 98.5 % bound to hemoglobin (Oxyhemoglobin) PaO2 determines SA02 Approx 25 % O2 utilized Each molecule of hemoglobin is fully saturated when 4 iron sites have oxygen molecules. Harder for first to bind than others Instructor Notes:

Common Respiratory Illnesses Asthma – Disease of the Upper airway,resulting in constriction, which is heard as Wheezing. Emphysema – disease process that affects the smaller airways, Bronchioles,Alveoli. ++ mucos production Bronchitis – Recurrent disease process that affects the larger airways. Instructor Notes:

Hypoxia Lack of sufficient O2 to allow proper functioning of the brain and other tissues Treatment of Hypoxia takes highest precedence in the treatment of any patient 7 Causes 1. Decreased FiO2 Halon Gas (eats O2) Methane Gas (displaces O2) Altitude Airway Obstruction Instructor Notes: If in doubt, put an 0xygen mask on the patient.

Hypoxia 2. Mechanical Cord Transection C.V.A- Tumor Drug Overdose Flail Chest Pneumothorax 3. Lung Disorders COPD (Emphysema, Chronic Bronchitis) Asthma Lack of Surfactant Pneumonia Instructor Notes: in addition, a pneumothorax need not be a “tension” to cause hypoxia

Hypoxia 4. Membrane Pathology that thickens membrane e.g. Interstitial Edema 5. Cardiac Output Pathology that decreases cardiac output M.I, Infection, Fast / Slow Heart Rate 6. Hemoglobin Lack of RBC’s(anemia) How well it binds with oxygen (carbon monoxide poisoning 7. Cell Histotoxic Hypoxia (cyanide poisoning) Instructor Notes:

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