tailieunhanh - The little ICU handbook (Second edition): Part 2

(BQ) Continued part 1, part 2 of the document The little ICU handbook (Second edition) has contents: Acid-Base analysis, organic acidoses, metabolic alkalosis, acute kidney injury, abdominal infections, abdominal infections, abdominal infections, nutritional requirements, parenteral nutrition, antimicrobial therapy,. and other contents. Invite you to refer. | Chapter 23 Acid-Base Analysis This chapter describes how to identify acid-base disorders using the pH PCO2 and bicarbonate HCO3 concentration in blood. Included are a simple rules for the identification of primary secondary and mixed acid-base disorders b formulas for determining the expected acid-base changes for each of the primary acid-base disorders and c a description of the anion gap and how it is used. I. ACID-BASE BALANCE According to traditional concepts of acid-base physiology the hydrogen ion H concentration in extracellular fluid is determined by the balance between the partial pressure of carbon dioxide PCO2 and the bicarbonate HCO3 concentration 1 H k X PCO2 HCO3 k is a proportionality constant . This means that all acid-base disorders are defined by two variables PCO2 and HCO3. This is shown in Table . A. Types of Acid-Base Disorders 1. A respiratory acid-base disorder is a change in H that is a direct result of a change in PCO2. According to Equation an increase in PCO2 will increase the H and produce a respiratory acidosis while a decrease in PCO2 will decrease the H and produce a respiratory alkalosis. 2. A metabolic acid-base disorder is a change in H that is a direct result of a change in HCO3. Equation predicts that an increase in HCO3 will decrease the H and produce a metabolic alkalosis while a decrease in HCO3 will increase the H and produce a metabolic acidosis. 3. Acid base disorders can be primary the principal disturbance or secondary an additional disturbance . Table Acid-Base Disorders and Compensatory Responses A H A PCO2 A HCO3 Ac id-Base Disorder Primary Change Compensatory Response Respiratory Acidosis tPCOj t HCOa Respiratory Alkalosis 4 PCO2 IHCOJ Metabolic Acidosis hcò3 ịpco2 Metabolic Alkalosis HCCy tPCO2 B. Compensatory Responses 1. Compensatory responses are designed to limit the change in H concentration produced by the primary acid-base disorder. This is accomplished by changing the secondary .