Transient respiratory difficulty following cesarian delivery

Inhaled epinephrine for the treatment of transient tachypnea of the newborn

OBJECTIVE

Infants with transient tachypnea of the newborn (TTN) have relatively low levels of epinephrine, which is known to mediate fetal lung fluid absorption. Providing exogenous epinephrine could be a valuable diagnostic and therapeutic intervention for this common condition. Our primary objective was to determine if inhaled racemic epinephrine is safe for the treatment of TTN. Our secondary objective was to determine its efficacy.

STUDY DESIGN

We conducted a randomized, blinded, placebo-controlled pilot trial. Inhaled racemic epinephrine or placebo was administered to 20 newborns with TTN. Physiologic variables of cardiopulmonary function were measured during and after treatment.

RESULT

No infant in either the treatment or control arm experienced an adverse event, including tachycardia or hypertension. We did not detect a difference between the two groups regarding rate of resolution of tachypnea.

CONCLUSION

We did not observe any adverse effects of inhaled racemic epinephrine when administered for the treatment of TTN. Larger studies are necessary to determine efficacy.

Randomised controlled trial of effect of terbutaline before elective caesarean section on postnatal respiration and glucose homeostasis

AIM

To determine if terbutaline given to mothers before elective caesarean section facilitates neonatal respiration and metabolism.

METHODS

A randomised controlled trial of 25 full term infants delivered by elective caesarean section was conducted. The mothers received a continuous infusion of terbutaline or saline 120-0 minutes before birth. Umbilical artery blood was collected at birth and analysed for blood gases and catecholamines. The lung function of each infant was assessed two hours after birth, and blood pressure, heart rate, blood glucose and body temperature were monitored until 24 hours of age.

RESULTS

The infants of the treated mothers (n = 13) had significantly higher dynamic lung compliance (p < 0.001), lower airway resistance (p < 0.001), and respiratory frequency than control infants (n = 12). Blood glucose and adrenaline concentrations were significantly higher in the treated group (p = 0.0014 and p < 0.01). None of these infants had any clinical respiratory difficulties; there were two cases of transient tachypnoea in the control group. No negative side effects due to the terbutaline treatment were seen among the infants. The mothers felt no discomfort caused by the terbutaline infusion, although they bled more during surgery (p = 0.03).

CONCLUSION

Stimulation of the beta adrenoceptors in utero with terbutaline infusion to the mothers promotes neonatal respiratory and metabolic adaptation after elective caesarean section.

Catecholamine abnormalities in transient tachypnoea of the premature newborn

The aim of the present study was to assess if there was an association between low catecholamine levels at birth in the premature infant and the development of TTN. Blood samples were collected at delivery from the umbilical artery of all preterm infants with a gestational age less than 36 weeks for determination of pH and catecholamine levels (noradrenaline and adrenaline). Amongst non-asphyxiated infants only, cord pH greater than 7.25 and/or Apgar score greater than 7 at five minutes, catecholamine levels were compared between the 10 infants who developed transient tachypnoea of the newborn (TTN) and 13 controls of a similar gestational age range (31-35 weeks) who developed no respiratory distress in the neonatal period. Infants who developed TTN were more often delivered without labour, 8 of 10 compared to 2 of 13 controls (p less than 0.01). There were no significant differences in adrenaline levels between the two groups. Noradrenaline levels, however, were significantly lower in the infants who developed TTN, being a median of 3.1 nmol/l (range 1.07-5.85 nmol/l) compared to a median of 6.4 nmol/l (range 2.38-22.83) in the controls (p less than 0.01). Infants who were delivered following labour had significantly elevated noradrenaline levels compared those delivered without labour (elective delivery) (p less than 0.05). These results suggest that low noradrenaline levels in preterm infants may explain the association in this group of TTN and "elective" delivery.