This tutorial covers the topic Hyperchloremic Acidosis (HCA). HCA is the only cause of "normal" anion gap metabolic acidosis and is almost always caused, in clinical practice, by excessive intravenous administration of isotonic saline (NaCl 0.9%) solution, most commonly as part of a diabetic ketoacidosis (DKA) "protocol". In the tutorial I explain that HCA is caused by a reduction in the Na-Cl strong ion difference (SID). The acidosis associated with NaCl 0.9% is more complex that merely a rise in plasma Chloride. Other serum electrolytes, Albumin and Hemoglobin are diluted - and this has an alkalinizing effect. Other resuscitation fluids have different impacts on acid base.
Hyperchloremia is also a feature of Renal Tubular Acidosis (RTA), various other nephropathies, the administration of acetazolamide and other drugs, and following surgical transplantation of the ureters into the small bowel,
If renal function is normal, and the Chloride level is lower than 125mmol/L, then the patient's kidneys will resolve the problem over 36 to 48 hours. If the Chloride is very high, acidosis will persist, particularly in patients with poor renal function, and Sodium Bicarbonate infusions may be warranted.
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Description
00:08 Introduction
01:49 Clinical Scenario 1 - DKA with acidosis that has not resolved
04:04 Mechanism of Hyperchloremic Acidosis
04:40 Strong Cations vs Strong Anions
07:08 Sodium to Chloride Ratio
07:44 Rules of Thumb regarding Anions
08:25 Clinical Scenario 2 - Perioperative Patient who receives 3L of NaCl 0.9%
10:00 Iatrogenic Hyperchloremic Acidosis
11:09 Impact of Saline on ECF Electrolytes and Proteins
12:09 The Anion Gap Revisited
17:09 Impact of Resuscitation Fluids on Plasma Electrolyte Concentrations (and Acid Base)
20:54 Other Mechanisms of Hyperchloremic Acidosis
24:09 Clinical Scenario 1 - Resolved - management of hyperchloremic acidosis
26:33 The Story Equation (Na-Cl)-35 = 0
27:21 Review