Breathing Patterns in Preterm and Term Infants Immediately After Birth

Abstract

There is limited data describing how preterm and term infants breathe spontaneously immediately after birth. We studied spontaneously breathing infants Ն29 wk immediately after birth. Airway flow and tidal volume were measured for 90 s using a hot wire anemometer attached to a facemask. Twelve preterm and 13 term infants had recordings suitable for analysis. The median (interquartile range) proportion of expiratory braking was very high in both groups (preterm 90 ͓74 -99͔ vs. term 87 ͓74 -94͔%; NS). Crying pattern was the predominant breathing pattern for both groups (62 ͓36 -77͔% vs. 64 ͓46 -79͔%; NS). Preterm infants showed a higher incidence of expiratory hold pattern (9 ͓4 -17͔% vs. 2 ͓0 -6͔%; p ϭ 0.02). Both groups had large tidal volumes (6.7 ͓3.9͔ vs. 6.5 ͓4.1͔ mL/kg), high peak inspiratory flows (5.7 ͓3.8͔ vs. 8.0 ͓5͔ L/min), lower peak expiratory flow (3.6 ͓2.4͔ vs. 4.8 ͓3.2͔ L/min), short inspiration time (0.31 ͓0.13͔ vs. 0.32 ͓0.16͔ s) and long expiration time (0.93 ͓0.64͔ vs. 1.14 ͓0.86͔ s). Directly after birth, both preterm and term infants frequently brake their expiration, mostly by crying. Preterm infants use significantly more expiratory breath holds to defend their lung volume. (Pediatr Res 65: 352-356, 2009)

Clinical Controversies in Aerosol Therapy for Infants and Children

“…Infants who are distressed or crying have larger and more variable V T , shorter inspiratory times, higher inspiratory flows, more prolonged expiratory times, and greater airway obstruction than at rest. 45,46 These factors may result in aerosolized drug depositing on the face and upper airways or being swallowed and absorbed into the gastrointestinal tract. Several investigators have evaluated drug delivery in infants at rest and under emotional distress.…”

Establishing lung gas volumes at birth: interaction between positive end-expiratory pressures and tidal volumes in preterm rabbits

“…In human neonates, V T s of 6.4 (4.1) ml/kg have been observed in term infants and Establishing lung gas volumes at birth Articles 6.7 (3.9) ml/kg in preterm infants, although it is unlikely that the very first breaths after birth were recorded in this study (29). In a separate study of babies receiving continuous positive airway pressure at birth, a variety of different respiratory patterns were observed with V T ranging from mean (SD) 3.1 (1.7) to 7.5 (4.2) ml/kg (30).…”

“…Although an arbitrary range of 4-8 ml/kg is considered to be the optimal V T range to target when ventilating preterm human infants, a recent study has demonstrated that many of the volumes delivered during resuscitation are inadvertently well outside this range (33). It is clear that some spontaneous breathing infants initiate tidal breathing exceeding 8 ml/kg (29,30). In newborn rabbits, V T reduces as aeration occurs (19).…”

A practical guide to neonatal volume guarantee ventilation

“…16 Forced expiration, 'splinting' and episodes with low tidal volume Babies can actively expire and then tighten their abdominal muscles so hard such that they prevent gas entering the lungs during an inflation; often termed 'splinting'. 54 Forced expiration and splinting cause hypoxemic episodes due to low lung volume and low V T delivery, 55 causing 'ETT obstructed' and 'low tidal volume' alarms ( Figure 6). A higher Pmax setting (for example, 35 cm H 2 O) may allow the ventilator to increase the PIP and overcome the obstruction more quickly.…”

“…55,56 Diaphragmatic braking Diaphragmatic braking causes an early interruption in expiratory flow ( Figure 7) and is sometimes associated with a small inspiration as the diaphragm contracts. 15,54 If this occurs within the 0.2 s refractory period of the ventilator an inflation is not triggered. However, the VG software underestimates the expired V T by incorrectly interpreting the small initial expired V T as the total expired V T , and increases the PIP for the next inflation.…”