Fluid replacement in diabetic ketoacidosis is critically important. Over-hydration can lead to life-threatening cerebral oedema, while under-hydration can lead to under-perfusion of vital organs. Estimating degree of dehydration is not easy. Recent guidelines assume 7–10% dehydration unless the patient is haemodynamically unstable. A Canadian study calculated degree of dehydration of 39 patients in 42 episodes of diabetic ketoacidosis from their weight at admission and on discharge, then compared degree of dehydration with clinical signs, biochemistry and fluids given. All patients recovered within 24 h using a uniform regimen of 10 m/kg boluses of 0.9% saline repeated until haemodynamically stable. The median degree of dehydration at presentation was 5.7% (25th–75th centiles, 3.8–8.3%). The degree of dehydration did not correlate with clinical signs, biochemical parameters, volume of fluid given per kilogram (see Figure) or rapidity of recovery. The authors recommended a relatively restrictive fluid regimen, to avoid cerebral oedema, unless the patient is haemodynamically unstable.
Reviewer: David Isaacs, Children's Hospital at Westmead, email@example.com