Respiratory movements in the fetal guinea pig in utero.
Intrauterine respiratory movements in the fetal guinea pig were detected from about 0.6 of term by the use of chronically implanted tracheal and amniotic catheters. Three distinct patterns were seen: 1) "slow" breathing recurring at a rate of 1-8/min; 2) "rapid irregular" breathing in which episodes last a few seconds to 40 min and the frequency of breathing is high (greater than 0.5 HZ) (the respiratory movements are associated with negative tracheal pressures of of 0.5-20 Torr); and 3) "rapid regular" breathing which recurs in bursts lasting 0.6-6.8 min with a maximum incidence of 3/h. Inspiratory efforts in the range of 10-20 Torr were uniform during a single episode. All three types of respiratory activity were continued into first stage labor, both during and between contractions, but were absent during second stage labor.
D000818:Animals; D036861:Delivery, Obstetric; D005260:Female; D006168:Guinea Pigs; D007747:Labor Stage, First; D007748:Labor Stage, Second; D008168:Lung / Q000196:embryology* / Q000502:physiology; D009068:Movement; D011247:Pregnancy; D012119:Respiration; D013909:Thorax