Lachmann B, Grossmann G, Nilsson R, Robertson B
Respir Physiol. 1979 Dec;38(3):283-302. doi: 10.1016/0034-5687(79)90055-0.
Rabbit neonates were tracheotomized on day 27--30 of gestation, and lung mechanics during spontaneous ventilation was registered with a fluid-filled esophagus catheter for pressure recording and a pneumotachograph connected to the tracheal cannula via a Fleisch tube. The first breath of all neonates had a very long inspiratory phase (less than or equal to 1.12 sec), with insufflation pressures amounting to 42 cm H2O in the mature animals. The expiration phase of the first breath was usually 'passive', i.e. there was no positive expiratory esophagus pressure. In animals delivered on day 27--28 there was, as a rule, no difference between inspiratory and expiratory tidal volume during the first few breaths, whereas such difference was regularly registered in mature animals; this phenomenon probably corresponds to the establishment of FRC. Dynamic lung compliance increased with both gestational and postnatal age, up to 60 min after delivery. Shortly after birth, pulmonary resistance was higher in immature animals than in fullterm ones, but at later intervals, there was no difference between survivors of various gestational age.
在妊娠第27至30天对新生兔进行气管切开术，通过一根用于压力记录的充满液体的食管导管和一个经弗莱施管连接到气管插管的呼吸流速仪，记录自主通气时的肺力学。所有新生兔的第一次呼吸吸气相都非常长（小于或等于1.12秒），成熟动物的充气压力达42厘米水柱。第一次呼吸的呼气相通常是“被动的”，即食管没有正呼气压力。在妊娠第27至28天出生的动物中，通常在最初几次呼吸时吸气潮气量和呼气潮气量没有差异，而在成熟动物中这种差异是经常记录到的；这种现象可能与功能残气量的建立相对应。动态肺顺应性随胎龄和出生后年龄增加，直至出生后60分钟。出生后不久，未成熟动物的肺阻力高于足月动物，但在随后的时间段，不同胎龄的存活者之间没有差异。
