A physicochemical approach to acid-base balance in critically ill trauma patients minimizes errors and reduces inappropriate plasma volume expansion.
BACKGROUND
This study assesses if a physicochemical (PC) approach to acid-base balance improves the accuracy of acid-base diagnosis, and reduces inappropriate fluid loading.


METHODS
Hundred consecutive patients with trauma admitted to a surgical intensive care unit at a level I trauma center were prospectively analyzed. Demographics, acid-base data and diagnoses, and interventions were collected. Patients were cared for by one physician using a PC approach, or four using conventional (CONV) acid-base balance techniques. The diagnoses and interventions made by CONV physicians were reviewed by the PC physician for accuracy and appropriateness using PC techniques. Data are mean +/- SD or percents; p values reflect PC evaluation of CONV analysis.


RESULTS
There were 50 PC patients and 50 CONV. There were no differences in age (p = 0.13), injury severity score (p = 0.21), number of operations (p = 0.87), transfusions (p = 0.87), or survival (p = 0.15). CONV missed 12 diagnoses of metabolic acidosis (p = 0.03), 10 of hyperchloremic metabolic acidosis (p = 0.003), 11 metabolic alkalosis (p = 0.02), and 19 tertiary disorders (p < 0.001). CONV missed 38 diagnoses of increased unmeasured ions (p < 0.001). PC normalized their acid-base balance sooner than CONV (3.3 days +/- 3.4 days vs. 8.3 days +/- 7.4 days, p < 0.01).


CONCLUSIONS
A PC approach improves acid-base diagnosis accuracy. CONV often miss acidosis (particularly those because of hyperchloremia), alkalosis, and tertiary disorders. Inappropriate volume loading follows in the wake of misinterpretation of increased base deficit using CONV and is avoided using PC. PC-directed therapy normalizes acid-base balance more rapidly than CONV.
Department of Surgery, Section of Trauma, Surgical Critical Care and Surgical Emergencies, Yale University School of Medicine, New Haven, Connecticut 06518, USA. lewis.kaplan@yale.edu
Lewis J
LJ
Kaplan
Nora Ham-Ting
NH
Cheung
Linda
L
Maerz
Felix
F
Lui
Kevin
K
Schuster
Gina
G
Luckianow
Kimberly
K
Davis
D000063:Accidents, Traffic; D000137:Acid-Base Imbalance / Q000175:diagnosis*; D000328:Adult; D000838:Anions / Q000097:blood; D001784:Blood Gas Analysis; D055598:Chemical Phenomena; D016638:Critical Illness; D003663:Decision Trees; D005440:Fluid Therapy; D006801:Humans; D007362:Intensive Care Units; D008875:Middle Aged; D010953:Plasma Volume; D014947:Wounds and Injuries / Q000503:physiopathology / Q000628:therapy; D014948:Wounds, Gunshot
D000838:Anions