Profile of acid-base disturbances in an intensive care unit of Fortaleza, Ceará, Brazil

Introduction: Acid ? base disturbances are entities caused by the deregulation of the concentration of bicarbonate ions, the concentration of hydrogen ions and the partial pressure of carbon dioxide in the blood. These disturbances modify most cell fuctions when present, damaging the proper functioning of organs. Methods: Transversal study based upon data collected from medical records of patients in ICU as seen from August 1 to December 31, 2013 at the Dr. José Frota Institute in Fortaleza, Ceará. The variables studied were: age, sex, cause of ICU admission, pH, HCO3-, pO2, pCO2, glomerular filtration rate (GFR), serum concentratrion of potassium and magnesium and serum levels of creatinine and hemoglobin. The chi-square and Fisher exact test were used to compare the proportions according to the number of cases. For quantitative variables, the analysis of variance (ANOVA) was used and the Kruskal-Wallis test if the Bartlett test presented p<0.05. Results: The most frequent disorders were primary respiratory alkalosis with 33 (38.4%) cases, 30 (34.9%) of metabolic alkalosis, 13 (15.1%) of metabolic acidosis, 7 (8.2%) did not present acid-base disorders and respiratory acidosis 3 (3.5%). Patients admitted with TBI had respiratory alkalosis as the most common primary disorder, followed by metabolic alkalosis, 16 (47.0%) and 13 (38.2%), respectively. The main disturbances mixed respiratory alkalosis with metabolic alkalosis and respiratory alkalosis with metabolic alkalosis found in 15.12% of patients in each of these combinations. Comparative evaluation of the means of the variables between groups of primary disorders were older (p=0.047), anion gap (p=0.037) and bicarbonate (p=0.013), with a statistically significant relationship. Conclusion: Patients who have suffered traumatic brain injury presented as primary disorder more common the respiratory alkalosis and the metabolic alkalosis. Ionic disturbances related to potassium and magnesium showed no statistically significant relationship when related to the acid-basic disturbances