Ebook Marino’s the ICU book (4/E): Part 2
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: Ebook Marino’s the ICU book (4/E): Part 2
Ebook Marino’s the ICU book (4/E): Part 2
ACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpli Ebook Marino’s the ICU book (4/E): Part 2icity, and distrust it.Alfred North WhiteheadManaging ICU patients without a working knowledge of acid-base disorders is like trying to clap your hands when you have none; i.e., it simply can't be done. This chapter presents a structured approach to the identification of acid-base disorders based on Ebook Marino’s the ICU book (4/E): Part 2 the traditional relationships between the pH, PCƠ2, and bicarbonate (HCO3) concentration in plasma. Also included is a section on the evaluation of mEbook Marino’s the ICU book (4/E): Part 2
etabolic acidosis using the anion gap and a measurement known as the "gap-gap." Alternative approaches to acid-base analysis, such as the "Stewart metACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpli Ebook Marino’s the ICU book (4/E): Part 2s.BASIC CONCEPTSHydrogen Ion Concentration and pHThe hydrogen ion concentration [H+] in aqueous solutions is traditionally expressed by the pH, which apparently means the power of hydrogen, and is a logarithmic function of the [H+]; i.e.,pH-log- log ỊH4-](31.1)The physiological range of pH and corre Ebook Marino’s the ICU book (4/E): Part 2sponding [H+] is shown in Table 31.1. The normal pH of plasma is indicated as 7.40, which corresponds to a [H+] of 40 nEq/L.Features of the pHThe relaEbook Marino’s the ICU book (4/E): Part 2
tionships in Table 31.1 illustrate 3 unfortunate features of the pH: (a) it is a dimensionless number, which has no relevance in chemical or physiologACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpli Ebook Marino’s the ICU book (4/E): Part 2as the pH decreases, the changes in [H+] become gradually larger with each change in pH. This means that changes in pH will have different implications for acid-base balance at different points along the pH spectrum. Although it is unlikely that the pH will be abandoned, it is not a representative m Ebook Marino’s the ICU book (4/E): Part 2easure of the acid-base events in the body.able 31.1 pH and Hydrogen Ion ConceE pH(H-J (nEq/14pH[H-] (nEq/L)G.91.2GI 7 440 I71007.5327.1807.6257.2647.Ebook Marino’s the ICU book (4/E): Part 2
720Z.3boZ.816Hydrogen Ions as a Trace ElementAlso evident in Table 31.1 is the fact that [H+] is expressed as nanoequivalents per liter (nEq/L). One nACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpli Ebook Marino’s the ICU book (4/E): Part 2s in extracellular fluid (sodium and chloride), whose concentration is expressed in mEq/L. This gives hydrogen ions the status of a trace element. How can such a small quantity of an ion have all the effects attributed to acidosis and alkalosis? Other trace elements certainly have important biologic Ebook Marino’s the ICU book (4/E): Part 2al effects, but it is also possible that changes in the [H+] are just one of several physicochemical changes that are taking place in the extracellulaEbook Marino’s the ICU book (4/E): Part 2
r fluid. This would explain why the same degree of acidosis is more life-threatening in lactic acidosis than in ketoacidosis (as described in the nextACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpli Ebook Marino’s the ICU book (4/E): Part 2H +] in extracellular fluid is determined by the balance between the partial pressure of carbon dioxide (PCO2) and the concentration of bicarbonate (HCO3) in the fluid. This relationship is expressed as follows (1):[H*l - 24 X (PCOj/HCQO-31.2The PCO2/HCO3 ratio identifies the primary acid-base disor Ebook Marino’s the ICU book (4/E): Part 2ders and secondary responses, which are shown in Table 31.2.Primary Acid-Base DisordersAccording to equation 31.2, a change in either the PCO2 or theEbook Marino’s the ICU book (4/E): Part 2
HCO3 will cause a change in the [H+] of extracellular fluid. When a change in PCO2 is responsible for a change in [H+], the condition is called a respACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpli Ebook Marino’s the ICU book (4/E): Part 2 responsible for a change in [H+], the condition is called a metabolic acid-base disorder: a decrease in HCO3 is a metabolic acidosis, and an increase in HCO3 is a metabolic alkalosis.able 31.2 Primary Acid-Base Disorders and Secoỉ AIH‘1 = APCO2/AHCO3Primary DisorderPrimary ChangeSecondary Response1 Ebook Marino’s the ICU book (4/E): Part 2Respiratory AddoslsĨPCQítHCOgRespiratory AlkalosisiPCOjÌHCO3Metabolic AcidosisÌHCO3iPCOgACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpliACID-BASE DISORDERSLife is a struggle, not against sin, not against money power... but against hydrogen ions.H.L. MenckenACID-BASE ANALYSISSeek simpliGọi ngay
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