ABSTRACT

• To estimate the normal anal canal pressure in neonates, anal manometry was performed in 46 normal babies less than 6 days of age. Twenty-eight of the subjects were boys and 18 girls. All the subjects passed meconium within 24 hours after birth. Birth weights were above 2.4 kg. There were no sexual differences in birth weight, birth height, gestational age, postnatal age, or Apgar score (p<0.05). The mean manometry values were; anal sphincter length 18.6± 3.9 mm, high pressure zone (HPZ) 9.2 ± 3.6 mm, vector volume 2027.2 ± 2440.7 mmHg2cm, maximum pressure 42.3 ± 17.4 mmHg, and position of the maximum pressure 6.0 ± 22.4 mm. Only the HPZ of boys was longer than those of girls (p=0.005). In squeezing state, HPZ and the position of maximun pressure were not changed from resting state. HPZ, vector volume, and maximum pressure in boys were higher than those in girls. As the birth weight increased, the anal sphincter length (p=0.001) and the HPZ increased (p=0.047). The resting pressures of the anal canal were evaluated in three portions; /23 upper portion, 12.8± 8.6mmHg, middle portion, 20.3 ± 10.8mmHg, and lower portion, 26.1 ± 12.9 mmHg. These normal values may serve as guidelines for the evaluation, diagnosis and treatment of neonatal anal diseases.
• Keywords: Anorectal manometry; Neonate; Pressure profile; Resting pressure