OBJECTIVE: Stewart's strong ion theory quantifies unmeasured tissue acids produced following hypoxia or hypoperfusion, by calculation of the strong ion gap. Our study objectives were as follows: a) to determine the 24-hr profile of the strong ion gap following cardiopulmonary bypass surgery; and b) to compare the prognostic value in terms of intensive care unit mortality of this variable with blood lactate. DESIGN: Prospective, observational study. SETTING: Tertiary pediatric intensive care unit. PATIENTS: Eighty-five children following surgery for congenital heart disease. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Arterial blood samples for lactate and strong ion gap calculation were obtained at intensive care unit admission and at 24 hrs. A raised strong ion gap (>3 mEq/L) was present in 41.1% and 51.7% of admission and 24-hr samples, respectively, being elevated at both time points in 30.5%. Both the strong ion gap and lactate increased with surgical complexity, but neither was correlated with length of bypass (r = .13 and -.02) or aortic cross-clamp (r = .13 and .10). The crude mortality was 5.8% (5/85). Four of the five deaths were associated with a persistently elevated strong ion gap, in contrast to two with ongoing hyperlactatemia (>2 mmol/L). The admission strong ion gap (cutoff, >3.2 mEq/L) was superior to lactate (cutoff, >3.0 mmol/L) as a mortality predictor (area under receiver operating characteristic curve of 0.85 [95% confidence interval, 0.74-0.95] vs. 0.71 [95% confidence interval, 0.44-0.98], respectively). CONCLUSIONS: An elevated strong ion gap occurs commonly following bypass surgery and appears to be superior to lactate as a mortality predictor.
OBJECTIVE: Stewart's strong ion theory quantifies unmeasured tissue acids produced following hypoxia or hypoperfusion, by calculation of the strong ion gap. Our study objectives were as follows: a) to determine the 24-hr profile of the strong ion gap following cardiopulmonary bypass surgery; and b) to compare the prognostic value in terms of intensive care unit mortality of this variable with blood lactate. DESIGN: Prospective, observational study. SETTING: Tertiary pediatric intensive care unit. PATIENTS: Eighty-five children following surgery for congenital heart disease. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Arterial blood samples for lactate and strong ion gap calculation were obtained at intensive care unit admission and at 24 hrs. A raised strong ion gap (>3 mEq/L) was present in 41.1% and 51.7% of admission and 24-hr samples, respectively, being elevated at both time points in 30.5%. Both the strong ion gap and lactate increased with surgical complexity, but neither was correlated with length of bypass (r = .13 and -.02) or aortic cross-clamp (r = .13 and .10). The crude mortality was 5.8% (5/85). Four of the five deaths were associated with a persistently elevated strong ion gap, in contrast to two with ongoing hyperlactatemia (>2 mmol/L). The admission strong ion gap (cutoff, >3.2 mEq/L) was superior to lactate (cutoff, >3.0 mmol/L) as a mortality predictor (area under receiver operating characteristic curve of 0.85 [95% confidence interval, 0.74-0.95] vs. 0.71 [95% confidence interval, 0.44-0.98], respectively). CONCLUSIONS: An elevated strong ion gap occurs commonly following bypass surgery and appears to be superior to lactate as a mortality predictor.
Authors: Mark Hatherill; Shamiel Salie; Zainab Waggie; John Lawrenson; John Hewitson; Louis Reynolds; Andrew Argent Journal: Intensive Care Med Date: 2007-03-22 Impact factor: 17.440
Authors: Diego E Gomez; Jeanne Lofstedt; Luis G Arroyo; Maureen Wichtel; Tammy Muirhead; Henri Stämpfli; J Trenton McClure Journal: Can Vet J Date: 2017-10 Impact factor: 1.008