[PHYSIO]LEC_009_VENTILATION_AND_PATTERNS_OF_VENTILATORY_DYSFUNCTION.pdf

(009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 OUTLINE I. VENTILATON A. Goals of Ventilation II. LUNG VOLUME AND CAPACITIES III. PATTERNS OF VENTILATORY DYSFUNCTI...

(009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 OUTLINE I. VENTILATON A. Goals of Ventilation II. LUNG VOLUME AND CAPACITIES III. PATTERNS OF VENTILATORY DYSFUNCTION IV. TEST YOURSELF V. REFERENCES I. VENTILATION Ventilation- is the process by which air moves in Figure 1. Alveolar Ventilaton and out of the lung. Ventilation and pulmonary blood flow (perfusion) -are important components of gas exchange in the lung. -the major determinant of normal gas exchange and thus the level of PO2 and PCO2 in blood is the relationship between ventilation and perfusion. This relationship is called the V/Q ratio. How atmospheric air moves in (of the lungs) and out of the alveoli Elements needed for air ventilation to commence Atmospheric air: ambient air Thoracic pump: ventilatory organs or respiration organs Air conduit: process or passages of respiratory tract —> nostrils down to the respiratory bronichioles Alveoli : where the actual gas exchange occurs Figure 2. Relationship between frequency of breathing and Lung Volumes tidal volume which in turn affects the minute ventilation Minute Ventilation In ventilation: bare in mind more emphasis on MV = TV x RR carbon elimination rather than alveolar Where: oxygenation MV = minute ventilation ⚫ Alveolar ventilation begins with ambient air. TV = tidal volume ⚫ Ambient air- is a gas mixture composed of N2 RR = respiratory rate and O2, with minute quantities of CO2, argon, and inert gases. NV = 6.8 Lilter per minute ⚫ Three important gas laws govern ambient air (In a 60 kilogram man) and alveolar ventilation:Boyle’s law, Dalton’s law, and Henry’s law. A. Goals of Ventilation Alveolar Oxygenation Carbon Dioxide (CO2) Elimination RED – PDF/BOOK; BLUE – AUDIO; BLACK - PPT PREPARED AND EDITED BY: LIMBAUAN, J., LIVED, R., LOCQUIAO, C., LOPEZ, F., PADILLA, A., PADOLINA, J., PALAGANAS, B., PANG-AG, L  (009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 A. Boyle’s law- states that when temperature is constant, pressure (P) and volume (V) are inversely related (P1V1 = P2V2). B. Dalton’s law- states that the partial pressure of a gas in a gas mixture is the pressure that the gas would exert if it occupied the total volume of the mixture in the absence of the other components. C. Henry’s law- states that the concentration of a gas dissolved in a liquid is proportional to its partial pressure. Alveolar oxygenation more discussed in the process of gas exchange compared to Figure 3. Lung Volume and Capacities ventilation Blue colored balls will affect frequency, resultant changes in the minute ventilation II. LUNG VOLUME AND CAPACITIES is expected with changes in the Blue colored balls ⚫ Measurement of expiratory flow rates and Tidal volume is affected by white colored balls expiratory volumes is an important clinical tool for evaluating and monitoring respiratory IMPORTANCE: Any changes involving tidal diseases. The test results are displayed either volume in frequency will affect and alter the as a spirogram or as a flow-volume curve/ minute ventilation loop. IF THERE IS DECREASE OR INEFECTIVITY OF ⚫ Spirogram- displays the volume of gas MINUTE VENTILATION, CARBON DIOXIDE exhaled as a function of time and measures: ELIMINATION WILL BE AFFECTED 1. Forced vital capacity (FVC) 2. Forced expiratory volume in 1 second An increase in arterial PCO2 results in (FEV1), respiratory acidosis (pH 7.45). Hypercapnia is defined as (FEF25-75). an elevation in arterial PCO2, and it is secondary to inadequate alveolar ventilation ⚫ Flow-volume curve or loop- created by (hypoventilation) relative to CO2 production. displaying the instantaneous flow rate Conversely, hyperventilation occurs when during a forced maneuver as a function of alveolar ventilation exceeds CO2 production, the volume of gas. and it decreases arterial PCO2 (hypocapnia). -This instantaneous flow rate can be displayed both during exhalation (expiratory flow-volume curve) and during inspiration (inspiratory flow-volume curve). The flow-volume loop measures: (1) the Flow Volume Curve (2) Peak expiratory flow rate (PEFR)- the greatest flow rate achieved during the expiratory maneuver (3) multiple expiratory flow rates at various lung volumes. RED – PDF/BOOK; BLUE – AUDIO; BLACK - PPT PREPARED AND EDITED BY: LIMBAUAN, J., LIVED, R., LOCQUIAO, C., LOPEZ, F., PADILLA, A., PADOLINA, J., PALAGANAS, B., PANG-AG, L  (009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 ⚫ Imagine when we are breathing air gets in and ONLY CAPACITY THAT CANNOT BE MEASURED out of the lungs everytime we breathe ARE THOSE INVOLVING RESIDUAL VOLUME V: Volume (RV) C: Capacity Total Lung Capacity (TLC): Entirety of air in -RV volume can only be surmissed by inference the lungs in any given time Subdivided into: MEASURED BY INFERENCES: Vital Capacity (VC) Functional Residual Volume (FRC) o The total volume of air that is Vital Capacity (VC) exhaled during a maximal forced Total Lung Capacity (TLC) exhalation from TLC to RV is called the FVC (Force Vital Capacity). III. PATTERNS OF VENTILATORY FVC is equal to VC. DYSFUNCTION Residual Volume (RV) Tidal Volume (TV): volume of air that goes in INGREDIENTS FOR PROPER VENTILATION: and out of the lungs in a normal quite Thoracic pump must be efficient and effective breathing in expanding the alveoli Inspiratory Reserved Volume (IRV): Inhaled Airway should not be obstructed for the air beyond the Tidal Volume (TV) passage of air from the atmosphere down Expiratory Reserved Volume (ERV): to alveoli Exhaled air beyond the Tidal Volume (TV) ⚫ Disorders in ventilation: look in particular into Forced expiratory volume in 1 second carbon dioxide elimination rather than (FEV1)- volume of air that is exhaled in the oxygenation first second during the maneuver. Larger ⚫ Work of breathing- work required to than ERV. overcome the inherent mechanical Residual Volume (RV): remaining air that properties of the lung (i.e., elastic and flow- stays in the alveoli after forceful inspiration resistive forces) and to move both the or expiration lungs and the chest wall. Peak expiratory flow rate (PEFR)- the ⚫ Respiratory muscle fatigue- most common greatest flow rate achieved during the cause of respiratory failure, a process in expiratory maneuver which gas exchange is inadequate to meet the metabolic needs of the body REMEMBER: Lungs and alveolar sacs are not TWO PATTERNS OF VENTILATORY completely impede after each exhalation: there is DYSFUNCTION: an amount of air left in order to maintain (based on which ingredient is affected): inflatability = Residual Volume (RV) RESTRICTIVE DEFECT OBSTRUCTIVE DEFECT Capacities (C) : are combination of volume Inspiratory Capacity (IC) = Tidal Volume (TV) + Inspiratory Reserve Volume (IRC) IC = TV + IRV Functional Residual Capacity (FRC) = Residual Volume (RV) + Expiratory Reserved Volume (ERV) FRC = RV + ERV -All of the lung volumes can be measured either directly or indirectly RED – PDF/BOOK; BLUE – AUDIO; BLACK - PPT PREPARED AND EDITED BY: LIMBAUAN, J., LIVED, R., LOCQUIAO, C., LOPEZ, F., PADILLA, A., PADOLINA, J., PALAGANAS, B., PANG-AG, L  (009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 *RESTRICTIVE DEFECT: -Any disorder affecting PAINT or Thoracic pump wil present with ventilatory dysfunction. Inability to expand alveoli: entry of air from atmosphere down to alveoli will be affected RESTRICTIVE DEFECT DECREASE LUNG VOLUME o In restrictive lung diseases such as pulmonary fibrosis, lung compliance is decreased. Lung volumes are decreased, but flow rates are reasonably normal. *OBSTRUCTIVE DEFECT: Figure 4. Restrictive Defect: Defective Thoracic Pump Thoracic Pump*/Lungs: if thoracic pump is ineffective: there is ventilatory dysfunction Structures included as thoracic pump: ⮚ P = Pleura* o Obstructive lung disease have an increase in positive pleural pressure during exhalation because of the increase in resistance and the increased expiratory workload Figure 5. Obstructive Defect: Defective nasal passages, ⮚ A = Alveoli trachea, tracheobronchial tree, bronchiles, alveolie o In chronic bronchitis, accumulation of mucus and airway inflammation Defective Airways: conduit of air from cause the equal pressure point to nostrils down to alveoli move toward the alveolus, which Hindrance to free passage of air leads to premature airway closure OBSTRUCTIVE DEFECT and increases in RV, FRC, and DECREASE AIRFLOW (VOLUME/TIME) TLC o Airway Resistance- Differs in airways ⮚ I = Interstitium of different size. In moving from ⮚ N = Neuromuscular* the trachea toward the alveolus, o In the third trimester of pregnancy, individual airways become smaller the enlarged uterus increases while the number of airway intra-abdominal pressure and branches increases dramatically. restricts movement of the o The smallest airways contribute very diaphragm.This change in lung little to the overall total resistance volume results in decreased lung of the bronchial tree. compliance and increased airway resistance in otherwise healthy Factors that contribute to airway resistance: women. o Airway mucus, edema, and ⮚ T = Thoracic cage contraction of bronchial smooth RED – PDF/BOOK; BLUE – AUDIO; BLACK - PPT PREPARED AND EDITED BY: LIMBAUAN, J., LIVED, R., LOCQUIAO, C., LOPEZ, F., PADILLA, A., PADOLINA, J., PALAGANAS, B., PANG-AG, L  (009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 muscle, all of which decrease the IV. TEST YOURSELF caliber of the airways o Increase gas density results in 1. Tidal volume is increase in airway resistance. (this a. total volume breathed in each minute increase can cause problems for b. volume breathed in each breath individuals with asthma and c. unaffected by the frequency of breathing obstructive pulmonary disease). o Breathing a low-density gas such as 2. True regarding Expiratory Reserve Volume an oxygen-helium mixture results a. maximal amount of air that can be exhaled in a decrease in airway resistance from the lungs after a normal expiration and has been exploited in the b. very small and NOT important in normal treatment of status asthmaticus. respiration c. kept at low volume so that the vast bulk of Neurohumoral Regulation of Airway the alveolar gas can be replaced with fresh Resistance air during the next inspiration ○ Stimulation of efferent vagal fibers- increased airway resistance and 3. True regarding Residual Volume decreased anatomical dead space a. mostly found in the anatomical dead space ○ Stimulation of sympathetic nerves b. volume of the gas left in the respiratory and release of NE- inh airway system after exhaling maximally constriction c. makes no contribution in maintaining the patency of the alveoli and terminal airways ○ Reflex stimulation of vagus nerve by inhalation of smoke, dust, cold air, 4. True about Vital Lung Capacity or other irritants- result in airway a. measure of the maximum volume of gas in constriction and coughing the respiratory system that can be ○ Histamine, acetylcholine, exchanged with each breath thromboxane A2, prostaglandin F2, b. measure of the amount of gas normally and leukotrienes (LTB4, LTC4, and exchanged with each breath LTD4)- released by resident cells (e.g., c. measure of the amount of gas that is vital to mast cells, airway epithelial cells) retain in the respiratory system at the end of and recruited cells (e.g., expiration neutrophils, eosinophils) in response to various triggers such 5. True about Inspiratory Reserved Volume as allergens and viral a. inspired air beyond the tidal volume infections.These cause constriction b. amount of inspired air beyond the total lung and increase in airway resistance capacity c. amount of air that is needed to be inspired ○ Methacholine- used to diagnose airway hyperresponsiveness 6. Total Lung Capacity (TLC): a. is a measure of the volume of gas in the respiratory system at the end of a maximal inspiration. b. increases as the frequency of breathing increases. c.is constant in amount from person to person. 7. In the respiratory system, the major difference between a volume and a capacity is that: a. a capacity is the sum of at least two volumes. b. a volume is the sum of at least two capacities. c. their units are different. RED – PDF/BOOK; BLUE – AUDIO; BLACK - PPT PREPARED AND EDITED BY: LIMBAUAN, J., LIVED, R., LOCQUIAO, C., LOPEZ, F., PADILLA, A., PADOLINA, J., PALAGANAS, B., PANG-AG, L  (009) VENTILATION & PATTERNS OF VENTILATORY DYSFUNCTION DR. DOMINETTA S. GONZALO| 11/24/2020 8. Forced Expired Volume in one second (FEV1): a. has the units of liters per minute. b. is the same whatever the starting volume in the airways. c. provides a measure of the resistance of the airways to flow. 9. During normal resting respiration, in the same breath: a. the volume of the exhaled gas exceeds that of the inhaled gas. b. the temperature of the exhaled gas is the same as that of the inhaled gas. c. the water content of the exhaled gas is that same as that of the inhaled gas. 10. These are related to obstructive defect in ventilatory dysfunction except: a. Decreased airflow due to mucus or edema b. Results in the hindrance of free passage of air c. Thoracic pump is ineffective resulting in the inability of alveoli to expand ANSWERS: 1.) B; 2.) A; 3.) B; 4.) A; 5.) A; 6.) A.; 7.) A; 8.) C; 9.) A; 10.) C. V. REFERENCES Koeppen, B. and Staton, B. (2010). Berne and Levy Physiology (6th ed.). Philadelphia: Mosby Elsevier RED – PDF/BOOK; BLUE – AUDIO; BLACK - PPT PREPARED AND EDITED BY: LIMBAUAN, J., LIVED, R., LOCQUIAO, C., LOPEZ, F., PADILLA, A., PADOLINA, J., PALAGANAS, B., PANG-AG, L