Introduction: There has been increasing evidence of detrimental effects of cumulative positive fluid
balance in critically ill patients. The postulated mechanism of harm is the development of interstitial
oedema, with resultant increase morbidity and mortality. We aim to assess the impact of positive fluid
balance within the first 48 hours on mortality in our local ICU population. Methods: This was a secondary
analysis of a single centre, prospective observational study. All ICU patients more than 18 years were
screened for inclusion in the study. Admission of less than 48 hours, post-elective surgery and ICU
readmission were excluded. Cumulative fluid balance either as volume or percentage of body weight from
admission was calculated over 6, 24 and 48 hour period from ICU admission. Results: A total of 143 patients
were recruited, of these 33 died. There were higher cumulative fluid balances at 6, 24 and 48 hours in nonsurvivors
compared to survivors. However, after adjusted for severity of illness, APACHE II Score, they were
not predictive of mortality. Sensitivity analysis on sub-cohort of patients with acute kidney injury (AKI)
showed only an actual 48-hour cumulative fluid balance was independently predictive of mortality (1.21
(1.03 to 1.42)). Conclusions: Cumulative fluid balance was not independently predictive of mortality in a
heterogenous group of critically ill patients. However, in subcohort of patients with AKI, a 48-hour
cumulative fluid balance was independently predictive of mortality. An additional tile is thus added to the
mosaic of findings on the impact of fluid balance in a hetergenous group of critically ill patients, and in subcohort
of AKI patients.