Effect of posture on respiratory function and drive in preterm infants prior to discharge.
Our objective was to determine the effect of posture on respiratory function and drive in prematurely born infants immediately prior to discharge. Twenty infants (6 oxygen-dependent), median gestational age 29 weeks (range, 25-32), were studied at a median postconceptional age (PCA) of 36 weeks (range, 33-39). On 2 successive days, infants were studied both supine and prone; each posture was maintained for 3 hr. The order on each day in which postures were studied was randomized between infants. At the end of each 3-hr period, tidal volume (Vt), inspiratory (Ti) and expiratory (Te) time, respiratory rate, and minute ventilation were measured. In addition, respiratory drive was assessed by measuring the pressure generated in the first 100 msec of an imposed airway occlusion (P(0.1)), and respiratory muscle strength was assessed by recording the maximum inspiratory pressure (Pimax) generated against an occlusion which was maintained for at least five breaths. Overall, tidal volume was higher (P < 0.05), but respiratory rate (P < 0.05), P(0.1) (P < 0.05), and Pimax (P < 0.05) were lower in the prone compared to the supine position. There were no significant differences in Ti or Te between the two postures. In oxygen-dependent infants only, minute volume was higher in the prone position (P < 0.05). In conclusion, posture-related differences in respiratory function are present in prematurely born infants studied prior to neonatal unit discharge.
Leipälä
J A
JA
Children Nationwide Regional Neonatal Intensive Care Centre, Golden Jubilee Wing 4th Floor, King's College Hospital, London SE5 9RS, UK.
Bhat
R Y
RY
Rafferty
G F
GF
Hannam
S
S
Greenough
A
A
D004328:Drive; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D010102:Oxygen Inhalation Therapy; D011187:Posture / Q000502:physiology*; D016684:Prone Position / Q000502:physiology; D012119:Respiration; D016683:Supine Position / Q000502:physiology; D013990:Tidal Volume