CHANGING PATTERNS OF RESPIRATION IN NEWBORN INFANTS

[摘要] The respiratory activity of quiet and sleeping healthy infants has been studied by pneumographic tracings and by clinical observations. Four successive stages of respiration have been described through which all healthy, full term newborn infants pass.The first stage is concerned with the establishment of postnatal respirations and lasts for a few minutes following birth.The second stage lasts from several hours to a day or more. Respiratory activity is characterized by a wide range of rates, a regular rhythm and a single respiratory pattern, to which the term "synchronous" has been given. The term is based on the fact that all parts of the chest and abdomen expand and contract together in an easy, smooth and regular fashion. Any signs of chest retraction indicate that the infant either is not well or has passed into the third stage.The third stage lasts several days or weeks. Infants in this stage exhibit rapidly fluctuating rates, variable rhythms and a wide variety of respiratory patterns. Two of the common patterns seen in this stage have been given the terms "simple retraction" and "see-saw." In simple retraction the lower end of the sternum and adjacent costal margins are pulled inwards as the abdomen and upper chest expand. In "see-saw" breathing the whole anterior chest wall is pulled inwards and downwards as the abdomen expands. There is much shifting back and forth from one pattern to another.The fourth stage begins several weeks after birth and is characterized by a return to more stable rhythms and respiratory patterns. All previous bizarre patterns have disappeared leaving "synchronous" and "simple retraction" as the only patterns of breathing.The same four stages of respiration have been identified in a small group of surviving premature infants.Knowledge of these stages has made it possible to give a more accurate prognosis during the first 24 hours of life on the infant's chances for survival The absence of retraction during stage 2 has been associated with an excellent prognosis for the infant. The presence of any degree of retraction in the first 24 hours of life, except as it may occur in the first few minutes after birth, has been associated with serious illnesses in the infants in the small series of cases observed to date.Factors which might explain the presence of stages 2, 3 and 4 have been explored only partially. One of the factors involved in the change from stages 2 to 3 is the increasing vigor of diaphragmatic contractions.

[学科分类] 儿科学