Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++Figure 43-1. Normal CapnogramGraphic Jump LocationView Full Size|Favorite Figure|Download Slide (.ppt)(I) Anatomic dead space.(II) Transition from anatomic dead space to alveolar plateau.(III) Alveolar plateau (typically slight upward slope).Reproduced from Longnecker DE, Brown DL, Newman MF, Zapol WM. Anesthesiology. Figure 31-7. Available at: http://www.accessanesthesiology.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved. ++ Healthy lungs: 2–3 mm Hg awake, 5–8 mm Hg anesthetizedCOPD: up to 10 mm Hg awake, 15–20 mm Hg anesthetizedFurther increased by heat/moisture exchangerFurther increased by V/Q mismatch: PE, hypovolemia, lateral position ++Table Graphic Jump LocationFavorite Table | Download (.pdf) | PrintCauses of Acute Changes in CapnogramExponential decreaseIncreased dead space (suspect PE or arrest)Sudden drop to zeroLikely circuit disconnectGradual decrease but not to zeroLeakage or partial obstruction of airwayAir embolism, PEDrop in CO: hypovolemia, IVC cross-clampingDecrease in metabolic rate: hypothermia, deep anesthesiaGradual increaseProlapse of expiratory valve or decreased minute ventilationSudden increaseRelease of tourniquet, aortic unclamping, MH ++Figure 43-2. Changes in Capnogram in Different Disease StatesGraphic Jump LocationView Full Size|Favorite Figure|Download Slide (.ppt)(A) A normal capnograph demonstrating the three phases of expiration: phase I—dead space; phase II—mixture of dead space and alveolar gas; phase III—alveolar gas plateau. (B) Capnograph of a patient with severe chronic obstructive pulmonary disease. No plateau is reached before the next inspiration. The gradient between end-tidal CO2 and arterial CO2 is increased. (C) Depression during phase III indicates spontaneous respiratory effort. (D) Failure of the inspired CO2 to return to zero may represent an incompetent expiratory valve or exhausted CO2 absorbent. (E) The persistence of exhaled gas during part of the inspiratory cycle signals the presence of an incompetent inspiratory valve. Reproduced from Morgan GE, Mikhail MS, Murray MJ. Clinical Anesthesiology. 4th ed. Figure 6-25. Available at: http://www.accessmedicine.com. Copyright © The McGraw-Hill Companies, Inc. All rights reserved. ++1. Swedlow DB. Capnometry and capnography: the anesthesia disaster early warning system. Semin Anesth. 1986;3:194–205.++2. West JB. Respiratory Physiology: The Essentials. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2000. ++3. Berengo A, Cutillo A. Single-breath analysis of carbon dioxide concentration records. J Appl Physiol. 1961;16:522–530. GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. Access My Subscription GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessAnesthesiology 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessAnesthesiology Full Site: One-Year Individual Subscription $995 USD Buy Now View All Subscription Options