TITLE:
Comparative Study between Traditional Approach and Physico-Chemical Approach in Acid Base Disorders Interpretation in Critically Ill Patients
AUTHORS:
Atef Redwan, Rainer Gatz, Naglaa Hassan, Heba Matter, Adel Hammodi, Adel Attia
KEYWORDS:
Anion Gap; Base Excess; Bicarbonate; Strong Ion Gap; Total Weak Acids
JOURNAL NAME:
Open Journal of Respiratory Diseases,
Vol.3 No.4,
October
17,
2013
ABSTRACT: Objective: The traditional approach
for acid base interpretation is based on Handerson-Hasselbalch formula and includes Base
Excess (BE), bicarbonate (HCO3), albumin corrected
anion gap. The Physicochemical approach is centered on the Carbon Dioxide
tension (PCO2), the strong ion difference (SID), strong ion gap (SIG) = SID
apparent-SID effective and totally weak acids (Atot). The study aims to
compare between the traditional approach and the physicochemical approach in
acid base disorder interpretation. Design: Prospective
observational study in an adult Intensive Care Unit (ICU) recruiting six
hundred and sixty one patients. Methods: Arterial blood samples were analyzed to measure pH, PaCO2 sodium, potassium, chloride and lactate. Venous blood
samples were analyzed to measure ionized calcium, magnesium, phosphorous and albumin. These samples were interpreted by both techniques. Results: Normal HCO3 and BE were
detected by traditional approach in 49 cases of which SIG acidosis was detected
in 22 cases (46%) and Hyperchloremic acidosis was detected in 29 cases (60%) by
physicochemical method. SIG was elevated in 72 cases (58%) of 124 cases with
high anion gap acidosis. SIDeff and BE were strongly correlated, r = 0.8, p 0.0001,
while SIG and Albumin corrected Anion Gap (ALAG) were moderately correlated r =
0.56, p Conclusion: Both approaches are
important for interpretation of the acid base status. Traditional approach
identifies the diagnostic description without many calculations and detects body
compensatory response to acid base disorders. Physicochemical approach is essential
to identify the exact causation and the severity of the acid base disorders.