ABSTRACT
Introduction .................................................................................................................................... 140 Body Fluid Compartments ............................................................................................................. 140 Effects of Starvation and Critical Illness on Fluid/Electrolyte Status............................................ 141 Requirements for Fluid and Electrolytes ....................................................................................... 141
Fluid .......................................................................................................................................... 141 Electrolytes ................................................................................................................................ 142
Fluid and Sodium Disorders .......................................................................................................... 144 Hyponatremia ............................................................................................................................ 144 Hypernatremia ........................................................................................................................... 144
Electrolyte Disorders ..................................................................................................................... 146 Potassium .................................................................................................................................. 146 Magnesium ................................................................................................................................ 147 Calcium ..................................................................................................................................... 148 Phosphorus ................................................................................................................................ 151
Acid-Base Disorders ..................................................................................................................... 153 Metabolic Acidosis .................................................................................................................... 154 Metabolic Alkalosis ................................................................................................................... 157 Respiratory Acidosis ................................................................................................................. 158 Respiratory Alkalosis ................................................................................................................ 159
Fluid and Electrolyte Issues in Critical Care ................................................................................. 159 Medication-Induced Electrolyte Disorders ............................................................................... 160 Parenteral Electrolyte Product Shortages .................................................................................. 160 Electrolyte Compatibility with EN or PN ................................................................................. 161
Patient Case .................................................................................................................................... 162 What Approach Should Be Taken for Proper Fluid/Electrolyte Management When Initiating Parenteral Nutrition? ...................................................................................................................... 163 Develop a Plan for Initiation, Monitoring, and Management of PN .............................................. 163 Summary ........................................................................................................................................ 163 References ...................................................................................................................................... 165
Critically ill patients manifest a multitude of uid, electrolyte, and acid-base disturbances. Nutrition support in the form of enteral tube feeding or parenteral nutrition (PN) may be associated with these disorders either by being a primary cause or by being the major mode of treatment. As such, the clinician providing nutrition support must know basic and advanced concepts of uid, electrolyte, and acid-base balance. The purpose of this chapter is to summarize the etiology, symptoms, and treatments of uid, electrolyte, and acid-base disorders commonly observed in the intensive care patient receiving nutrition support.
