Respiratory Physiology | Methods for Diagnostic & Therapeutic Studies | Respiratory Problems in Critical Care
Base excess can be misleading in acute respiratory acidosis
S Kocsi, K Kiss*, B Szerdahelyi, Z Molnar
*Corresponding author: K Kiss
Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
F1000Posters 2011, 2: 333 (poster) [ENGLISH]
Poster [502.21 KB]
Presented at
31st International Symposium on Intensive Care and Emergency Medicine ISICEM 2011,
20 - 23 Mar 2011, P136
There are two primary schools in the interpretation of blood gas analysis: the Boston school and the Scandinavian school. As it’s known, actual HCO3-level is a metabolic parameter derived directly from the Henderson-Hasselbalch equation, meanwhile the base excess (BE) is an in vitro calculated value.
The aim of our study was to investigate the relationship between BE and bicarbonate in critically ill patients after admission to the Intensive Care Unit. In the present retrospective study arterial blood gas samples of 88 patients were analysed.
There was a strong, significant correlation between BE and HCO3 in the whole sample and also in patients with pCO2 higher than forty-five mmHg. In patients with elevated pCO2 we have created 2 groups, those, who 's pH was normal and those who were acidotic. Regarding the actual HCO3 with 2 diffeerent cut offs: it showed very good specificity and low sensitivity for respiratory acidosis. On the contrary BE indicated metabolic acidosis with very high sensitivity (false positive result) therefore it seems to be a poor metabolic indicator.
Our results give further evidence, that the HCO3 is a more reliable parameter as compared to the BE to analyse acid-base balance in acute circumstances, especially in acute respiratory acidosis.
No relevant conflicts of interest declared.
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