[Usefulness of acid-base and electrolyte balance in acute gastroenteritis]

Blood analysis blood is frequently requested for evaluating patients with acute gastroenteritis who come to our emergency department, but there are few studies that determine its real usefulness in the management of these patients.

a) To determine the reasons why paediatricians request laboratory tests in patients with acute gastroenteritis; b) to establish the type and frequency of laboratory abnormalities found in these patients; c) to evaluate the ability of paediatricians to predict laboratory abnormalities in children with acute gastroenteritis from the history and physical examination; d) to assess the frequency with which these laboratory findings change the initial management of the patient, and e) to determine whether there is an association between clinical and analytical results, and length of hospital stay.

Over a period of 4 months, children between 3 months and 18 years with symptomatic acute gastroenteritis seen in the emergency department and had laboratory tests requested by the paediatrician were included.

Of the 4,172 children seen with acute gastroenteritis, 163 patients who had laboratory tests done were included in the study. The most common reason for requests was clinical suspicion of dehydration in 67.5 %. Abnormal results were seen in 77.9 % of cases, mainly metabolic acidosis (72.4 %). The sensitivity analysis to predict an analytical abnormality was 64.6 % with a specificity of 61.1 %. Electrolyte disorders caused a change in the initial management in 12.3 % of patients, with 85.3 % of patients requiring hospital admission; bicarbonate, sodium, creatinine and urea values correlated with a hospital stay of more or less 24 hours.

History and physical examination have limitations in predicting the presence of clinically significant electrolyte abnormalities in patients without clinical signs of dehydration or mild dehydration. Some laboratory tests correlate well with the length of patient stay in hospital.