Table 3.

Summary of studies comparing the prognostic power of the traditional and Stewart's approacha

Author/Year (ref)Study DesignPatient PopulationClinical and Laboratory MeasurementsEnd Point(s)ResultsComments
Balasubramany et al.(33), 1999Retrospective pediatric ICUn = 255 patients with simultaneous measurements of acid-base parametersBE, AG, BEua,b LactateIn-hospital mortalityBEua (ROC 0.79) performed better than AG (0.64), and lactate level (0.63), BE (0.53)BEua is used instead of SIG AGc not reported
Rocktaeschel et al.(36), 2003Retrospective adult ICUn = 300 patients with simultaneous measurements of acid-base parametersBE, AG, AGc, BEua,b lactate, APACHE IILactate level and in- hospital mortalityBE, BEua, AG good predictor of lactate >5 but not mortality ROC BEua 0.64, AGc 0.67, BD 0.59, and AG 0.66 APACHE II best predictor of mortalityBEua used instead of SIG
Hatherill et al.(37), 2003Prospective observational pediatric ICUn = 46 children with shockBE, AG, SIG, Lactate, PIMICU mortalityOnly ROC for lactate (0.83) and PIM (0.71) are significantOverall mortality in this cohort 35%
Kaplan and Kellum (38), 2004Retrospective observational surgical ICUn = 282 vascular trauma patientsBD, AG, SID, SIG, ISI, lactate28-d mortalitypH, BD, lactate, AG, SID, SIG predict survival; SIG, AG with ROC 0.99Single measurement in emergency department; AGc not reported
Martin et al.(32), 2005Retrospective surgical ICUn = 2152, laboratory tests in 427 trauma patientsBD, AG, AGc, SIDa, SIDe, SIG, BEua, ISILactate level and mortalityAGc and SIG best predicted lactate level ROC for AGc 0.68 and BEua 0.70 best predicted mortalityIn univariate, age and ISI and most acid-base parameters predictor of mortality
Gunnerson et al.(39), 2008Retrospective observational medical and surgical ICUn = 851 suspected lactic acidosis; other tests done within 4 hSID, SIG, lactate, BE, AGc, ageIn hospital mortalityIn logistic regression analysis, lactate and SIG as well as age and serum phosphate predicted mortality; good correlation between SIG and AGcAGc for albumin as well as lactate
Kaplan et al.(40), 2008Prospective surgical ICUn = 78 consecutive patients with major traumaSBE, AG, AGc, SIG, lactate28-d mortalityROC for SIG 0.959 greater than for AGc of 0.8628-d mortality 33%
  • a ICU, intensive care unit; ISI, injury severity score; PIM, pediatric index mortality; ROC, receiver operator characteristic curve.

  • b BEua is base excess corrected for water content as well as chloride, albumin, and Pco2 and reflects changes in BE as a result of presence of abnormal anion. This correlates closely with SIG. For details of the calculation, please refer to reference (33).