Sodium administration in critically ill patients in Australia and New Zealand: a multicentre point prevalence study

Inadvertent sodium administration in excess of recommended daily requirements has been reported during routine care of critically ill patients.

To determine the amount and sources of sodium administered in Australian and New Zealand intensive care units.

Prospective, observational, single-day, point prevalence survey conducted in 46 Australian and New Zealand ICUs on 21 September 2011. All patients present in ICU at 10 am and not receiving an oral diet on the study day were evaluated. Demographic data, ICU admission diagnosis, Acute Physiology and Chronic Health Evaluation (APACHE) II score and sources of sodium administration over the study day were recorded.

356 patients (64% male) were enrolled. Mean (SD) age and weight were 58.5 years (18.0 years) and 81.6 kg (24.0 kg), respectively. Mean ICU admission APACHE II score was 20 (SD, 8). Overall median (interquartile range [IQR]) sodium administration was 224.5 mmol (IQR, 144.9-367.6 mmol), or 2.8 mmol/kg (IQR, 1.6-4.7 mmol/kg). Among patients who were on Day 2-10 of their ICU admission on the study day, sodium sources and amounts administered were: i) maintenance or replacement intravenous (IV) infusions, 69.3mmol; 30.9% of all sodium sources; ii) IV fluid boluses, 36.5 mmol; 16.3%; iii) IV drug boluses, 27.6 mmol; 12.3%; iv) enteral nutrition, 26.5 mmol; 11.8%; v) IV drug infusions, 19.3 mmol; 8.6%; vi) IV flushes, 16.6mmol; 7.4%; vii) blood products, 13.5 mmol; 6%; viii) IV antimicrobials, 11.2mmol; 5%; and ix) parenteral nutrition, 4.3 mmol; 1.9%. Factors associated with sodium administration were site (P = 0.04), age (P < 0.001), administered fluid (P = 0.03) and day of ICU stay (P = 0.01) (multiple linear regression).

This point prevalence study suggests that sodium administration in excess of recommended daily requirements may be common in Australia and New Zealand ICUs. The main sodium source was IV maintenance fluids, followed by fluid boluses and drug boluses.