Effect of isotonic and hypotonic fluid therapy on serum sodium: A Randomized Controlled Trial

There is little consensus about type of the maintenance fluid therapy and it’s effect on serum sodium in adults. Thus, this study was conducted to assess the effect of maintenance fluid therapy on serum sodium of hospitalized patients in intensive care unit. This randomized clinical trial was carried out on 64 patients aged 18-90 years hospitalized in intensive care unit (ICU) of Imam Sadjad and Shahid Beheshti hospitals, Yasuj, Iran in 2017. These patients were randomly allocated to take 2500-3000 milliliter of intravenous maintenance isotonic (0.9% saline) or hypotonic (0.45% saline) fluids daily. Blood and urine samples were taken to measure biochemical parameters before and 48 hours after intervention.  Data analyses were done by using SPSS 16 software via descriptive and analytic statistics. Twenty eight patients in 0.9% saline group (19 male and 9 female) and 32 patients in 0.45% saline (20 male and 12 female) completed the study. There was no significant difference between two groups in sodium (P=0.94), potassium (P=0.21), sugar (P=0.91), creatinine (P=0.21), Blood Urea Nitrogen (P=0.99), systolic (P=0.81) and diastolic (P=0.73) blood pressure, PH(P=0.27), bicarbonate(P=0.8), and urine specific gravity(P=0.73). Based on the results of this study, it was shown that administration of maintenance hypotonic fluids has been appropriate for the patients and will not face them with the risk of hyponautremia.