1.1 Regarding fluid and electrolyte homeostasis in a child:

Normal maintenance requirement in a child weighing 20 kg is 1.5 litre/day

A fluid deficit of 50ml/kg produces a body weight loss of 10%

Hypotension is a useful sign, which indicates moderate dehydration

Normal maintenance needs of sodium are 5-6mmol/kg/day

The characteristic metabolic abnormality in a child with pyloric stenosis is hyperkalaemic hypochloraemic metabolic alkalosis