Technical improvement for anorectal manometry in newborns.

A modification of the anorectal manometric technique has been devised to improve its accuracy in 31 low-weight newborn and premature infants. The characteristics of the probes used allowed long recording sessions without any sedation of patients. The pressure records fit well the classically accepted requisites. All recordings showed spontaneous fluctuating waves and increased mean pressure in the aboral direction. The anorectal reflex was observed in all cases. Clear reflex waves were recorded in the most caudal third of the anal canal. In this zone the recording showed more distinct features with respect to fluctuation and relaxation waves than those located in more proximal parts. The validity of this technique is unquestionable from the view of the reliability of the recordings independent of the weight, gestational age, and birth age of the infants.