Respiration Part 1 PDF

Respiration Part 1 Dr. Rita DelloStritto, PhD NURS 4043 Movement of O2 and CO2 Primary function of the Lungs Exchange of Oxygen and Carbon Dioxide Inhale Oxygen – from the atmosphere - 21% O2 Concentration Transferred via arteries to cells Exhale Carbon Dioxid...

Respiration Part 1 Dr. Rita DelloStritto, PhD NURS 4043 Movement of O2 and CO2 Primary function of the Lungs Exchange of Oxygen and Carbon Dioxide Inhale Oxygen – from the atmosphere - 21% O2 Concentration Transferred via arteries to cells Exhale Carbon Dioxide – from the body/cells Transferred to lungs from veins CO2 ≈ 35 – 45 Exchange occurs at the Alveolar level;  Tissue Exchange (A) Diffusion of oxygen from a tissue capillary into a tissue cell. (B) Diffusion of carbon dioxide from a tissue cell into a tissue capillary. Oxygen Transportation Dissolved in Diffuses across the capillary membrane into cell  bound O2 to Plasma – release from the Hemoglobin into the PaO2 plasma and diffuse into cells Bound to Hemoglobin Most common way of transportation – O2% Oxyhemoglobin Dissociation Curve A – Shifts to left  Hgb  affinity for O2 B – Normal Curve C – Shifts to Right  Hgb  affinity for O2 Key Points for Dissociation Curve The steep lower portion shows that the ability of The flat upper portion Plots the relationship the peripheral tissues to shows that the between dissolved withdraw large amounts saturation of Hgb oxygen and hemoglobin- of oxygen from the Hgb remains high even as the bound oxygen. with only a small change PaO2 declines. in PaO2. A shift to the right A shift to the left indicates indicates a lower O2% level for any given a higher O2% for any PaO2 and O2 delivery at given PaO2, but oxygen the tissue level is delivery to the tissues is enhanced. impaired. Diagnostic Procedures  Bronchoscopy Fiberoptic visualization of the bronchioles Diagnostic Wash Biopsy FB removal Patient is sedated Thoracentesis Removal of fluid from the plural space Diagnostic tests of fluid Infection Cancer Pneumonia Etc.  4 Components Lung Volume Mechanics of Breathing Diffusion Arterial Blood Gases Pulmonary Note: Rarely are all 4 done for critically ill Function Tests See Table 18.6 Lung Volumes and Capacities The amount of air exhaled during the Tidal relaxation phase of respiration. Volume Normal ≈ 500 ml Minute Volume/ Ventilation = VT x Resp (VT) Rate Maximum amount of air that can be Vital exhaled after maximal inhalation Capacity Normal = 4600 – 4800 ml 10 – 15 ml/kg minimal to wean from (VC) vent  Dynamic vs Static Compliance How easy it is to inflate the lungs Dynamic Compliance – 46 – 66 Static Compliance – 57 – 85 ml/cm H2O ml/cm H2O Measured during breathing Measured when lungs are at cycle rest   decrease lung compliance Decreased with decrease in Airway resistance lung compliance Increased Secretions Pneumothrax Bronchial Spasms Atelectasis Pulm. Edema Chest Wall Restrictions Ventilation vs Perfusion Perfusion – Blood Ventilation – the reaching/perfusing Ventilation/ act of breathing in the lungs  Gas Perfusion Match an out Exchange The gas inhaled and reaches Normal – V/Q Alveoli = Blood ration 1:1 Perfusing the Lungs V/Q Mismatch Causes Prevention of Gas getting to Alveoli (Ventilation) Examples? Reduced perfusion (blood) to the Alveoli Examples? V/Q Mismatch Ventilation Issues Hypoventilation Decrease O2 to Alveoli/minute Results in Increased PaCO2 Decreased PaO2 V/Q Mismatch Perfusion Issues Intrapulmonary Shunting Deoxygenated blood returns to left heart Physiological shunt = small amount of blood not exchanging at alveoli Pathological shunt = large amount of blood not exchanging at alveoli   PaO2 Pulmonary Shunt (Ventilation) vs Dead Space (Perfusion) Questions?