Concepts of the Strong Ion Difference Applied to Large Volume Resuscitation

Abstract

Concepts of the strong ionThe alternate method of evaluating acid-base status difference applied to large volume resuscitation. J Intensive Care as a function of the strong ion difference, PaCO 2 , Med 2001;16:169-176. and other weak acids is important for patients re-The occurrence of acidosis following trauma or other clinical quiring rapid intravenous administration of large conditions that require large volumes of resuscitation fluid volumes of fluids. This system was developed and may be modified by manipulation of the physical chemistry published by Stewart [1] more than a decade ago properties of substances within plasma. These include the and has gained increasing popularity in multidiscistrong ion difference, modification of hydrogen ion production through control of alveolar ventilation, and protection/ plinary critical care. Reviews of this method of analprovision of protein and phosphate-based weak acids. An ysis and related controversies have been presented understanding of these principles as an alternative method at many levels of biochemical complexity in a varito analyze/anticipate acid-base abnormalities is important ety of clinical disorders [2-6]. during resuscitation. Loss of protein-based weak acids may It is our intent to relate this system of analysis to the often occur after trauma or other conditions requiring largevolume resuscitation. These losses may potentially be retrauma patient during initial resuscitation or other placed with albumin-based colloid solutions. Large quantities patients requiring similar emergent fluid therapy. An of normal saline should be avoided so as to avoid hyperchlorunderstanding of Stewart's approach allows the emia-induced metabolic acidosis. Ringer's lactate solution is physician to anticipate acid-base changes and perpreferred. Alveolar ventilation must be adjusted so as to haps ameliorate them through proper selection of eliminate further hydrogen ion production caused by hypercarbia. The serum base excess and/or hyperlactemia have resuscitation fluids and adjustments in mechanical only limited value in diagnosing acidosis and guiding resusciventilation. Recognizing the severe consequences tation. Current experimental data and reviews of this topic of any altered acid-base balance [7], we will primarwere obtained from a Medline literature search. In addition, ily emphasize acidosis(emia) as this is the more the personal experience and investigations of the authors common abnormality during such clinical situain critically ill and injured patients were used to formulate recommendations.

Treatment of acute non-anion gap metabolic acidosis

“…The non-anion gap metabolic acidosis arising from aggressive administration of sodium chloride-containing solutions during operative procedures [ 12 ], treatment of volume depletion [ 3 ] and shock states [ 3 ] is becoming increasingly more prevalent. Indeed, in one study involving 70 patients in an intensive care unit, almost 50% had a non-anion gap pattern produced in this fashion [ 9 , 20 ]. A non-anion gap metabolic acidosis can also be observed in patients with diabetic ketoacidosis or other high anion gap metabolic acidoses where the loss of organic anions (potential base) in the urine is replaced with administered sodium chloride [ 21 ].…”