M G Coulthard. Will changing maintenance intravenous fluid from 0.18% to 0.45% saline do more harm than good? Arch Dis Child 2008;93:335–40. On page 338 of this article (column 1, paragraph 2, line 6) hypernatraemic should read hyponatraemic. In Box 2, (section “Infusing N/2 + 20 mmol/l potassium”) 102 should be 51, and 6.8 should be 3.4. In Box 2 (section “Infusing NS + 20 mmol/l potassium”) 372 should be 186, and 24.8 should be 12.4.