ATI Acid Base Imbalances Chapter 45

ATI Chap. 45 starts on next page after this review: HYPOXIA is low oxygen at the tissue/cellular level. HYPOXEMIA is low oxygen in the blood. From Lewis et al., 2017, p. 1594: • The INITIAL stage of shock occurs at a cellular level [due to hypoxia]. Metabolism at the cellular level changes from aerobic to anaerobic, causing lactic acid buildup. • Lactic acid ("lactate") buildup due to hypoxia is an early sign of shock. Think back to the Jordan Smith case study from last week: Lactate was an initial lab test to assess for and rule out shock (especially septic shock). • In the FINAL stage of shock (refractory stage), the patient demonstrates profound hypotension & hypoxemia. Where does LACTIC ACID come from? • Normal process: Aerobic metabolism. • Crisis: In shock, cells lose blood flow (and thus lose O2 delivery) • Abnormal process: anaerobic metabolism • Waste product generated: LACTIC ACID FYI on A&P (note: we will not be testing on this level of detail below)... Aerobic metabolism • glucose + oxygen = 36 ATP • utilizes Krebs cycle & electron chain Anaerboic metabolism ••glucose [no oxygen] = 2 ATP + lactic acid glycolysis only, no Krebs cycle or electron chain