Critically ill patient

Any history of renal insufficiency, renal disease, or elevated creatinine

Any history of intestinal anatomic abnormality (i.e. anal stenosis, anal surgery, bowel obstruction, hirschprung's disease)

An inability to self-report pain

Presence of gastrostomy or jejunostomy tube

Any history of gastrointestinal dysmotility

Inability to read or speak English or Spanish

A Trial of Three Types of Enemas Used to Treat Functional Constipation in Children