Fluid and electrolytes in the clinical setting.

The understanding of fluid and electrolyte balance in the clinical setting is often poor and prescribing is usually left to the most junior member of the team [1, 2]. Fluid prescriptions, especially in the perioperative period, can be very variable, with patients sometimes receiving in excess of 5 liters water and 500 mmol sodium/day [1, 3]. The 1999 UK National Confidential Enquiry into Perioperative Deaths reported that 20% of the patients sampled had either poor documentation of fluid balance or had unrecognized or untreated fluid imbalance [4], leading to increased postoperative morbidity and mortality [4]. In this review some of the pathophysiological aspects of fluid balance will be discussed and some recent and a few classic studies described, particularly in the context of nutritional and metabolic care.