Effect of PaCO2 variation on standard base excess value in critically ill patients.
OBJECTIVE
The aim of this study was to investigate the impact of acute Paco(2) temporal variation on the standard base excess (SBE) value in critically ill patients.


METHODS
A total of 265 patients were prospectively observed; 158 were allocated to the modeling group, and 107 were allocated to the validation group. Two models were developed in the modeling group (one including and one excluding Paco(2) as a variable determinant of SBE), and both were tested in the validation group.


RESULTS
In the modeling group, the mathematical model including SIDai, SIG, l-lactate, albumin, phosphate, and Paco(2) had a predictive superiority in comparison with the model without Paco(2) (R(2) = 0.978 and 0.916, respectively). In the validation group, the results were confirmed with significant F change statistics (R(2) change = 0.059, P < .001) between the model with and without Paco(2). A high correlation (R = 0.99, P < .001) and agreement (bias = -0.25 mEq/L, limits of agreement 95% = -0.72 to 0.22 mEq/L) were found between the model-predicted SBE value and the SBE calculated using the Van Slyke equation.


CONCLUSIONS
Acute Paco(2) temporal variation is related to SBE changes in critically ill patients.
Emergency Department, Intensive Care Unit, Hospital das Clínicas, University of São Paulo Medical School, São Paulo 0563010, Brazil. mpark@uol.com.br
Marcelo
M
Park
Alexandre Toledo
AT
Maciel
Danilo Teixeira
DT
Noritomi
Luciano Cesar
LC
Pontes de Azevedo
Leandro Utino
LU
Taniguchi
Luiz Monteiro
LM
da Cruz Neto
D000136:Acid-Base Equilibrium; D000137:Acid-Base Imbalance / Q000097:blood*; D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000097:blood*; D016638:Critical Illness; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010710:Phosphates / Q000097:blood; D011446:Prospective Studies; D015203:Reproducibility of Results; D012709:Serum Albumin / Q000032:analysis
D010710:Phosphates; D012709:Serum Albumin; D002245:Carbon Dioxide; D019344:Lactic Acid