Nursing 105

Essentials of Nursing Study Guide

©2018 Achieve Page 76 of 160 3.8 Pulmonary Volumes and Capacities Tidal Volume (TV) Amount of air inhaled or exhaled in one breath during quiet breathing (≈500 mL) Inspiratory Reserve Volume (IRV) Amount of air in excess of tidal volume that can be inhaled with maximum effort (≈3000 mL) Expiratory Reserve Volume (ERV) Amount of air in excess of tidal volume that can be exhaled with maximum effort (≈1200 mL) Residual Volume (RV) Amount of air remaining in the lungs after maximum expiration; the amount of air that can never be voluntarily exhaled (≈1300 mL) Vital Vapacity (VC) Amount of air that can be forcefully exhaled following a maximum inspiration (≈4700 mL) VC = ERV + TV + IRV Inspiratory Vapacity (IC) Maximum amount of air that can be inhaled following a normal expiration (≈3500 mL) IC = TV + IRV Functional Residual Capacity (FRC) Amount of air remaining in the lungs following a normal expiration (≈2500 mL) FRC = RV + ERV Total Lung Capacity Maximum amount of air in the lungs at the end of a maximum inspiration (≈6000 mL) TLC = RV + VC 3.9 Arterial Blood Gases ABG’s are performed to evaluate acid-base balance and oxygenation. ABG’s are a more accurate reflection of gas exchange. This procedure is performed only by specially trained lab or nursing staff due to the risk for hemorrhage after puncture. Direct pressure must be applied to the puncture site for 5-10 minutes to prevent adverse side effects. The normal blood pH range is 7.35 to 7.45. In order for normal metabolism to take place, the body must maintain this narrow range at all times. When the pH is below 7.35, the blood is said to be acidic . Changes in body system functions that occur in an acidic state include a decrease in the force of cardiac contractions, a decrease in the vascular response to catecholamines, and a diminished response to the effects and actions of certain medications.