Monochorionic twins share a single placenta with intertwin vascular anastomoses, allowing the transfer of blood from one fetus to the other and vice versa. These anastomoses are the essential anatomical substrate for the development of several complications, including twin-twin transfusion syndrome (TTTS) and twin anemia-polycythemia sequence (TAPS). TTTS and TAPS are both chronic forms of fetofetal transfusion. TTTS is characterized by the twin oligopolyhydramnios sequence, whereas TAPS is characterized by large intertwin hemoglobin differences in the absence of amniotic fluid discordances. TAPS may occur spontaneously in up to 5% of monochorionic twins and may also develop after incomplete laser treatment in TTTS cases. This review focuses on the pathogenesis, incidence, diagnostic criteria, management options and outcome in TAPS. In addition, we propose a classification system for antenatal and postnatal TAPS.
Objective. The pathophysiology of meconium aspiration syndrome (MAS) is related not only to mechanical obstruction of the airways and chemical injury to the respiratory epithelium but also to surfactant inactivation by meconium. A randomized, controlled study was performed to determine whether high-dose surfactant therapy improves the pulmonary morbidity of term infants ventilated for MAS. Methods. Forty term infants receiving mechanical ventilation for MAS were enrolled in this trial, in which the infants in the study group (n = 20) received up to four doses of 150 mg (6 mL)/kg beractant (Survanta), instilled every 6 hours by continuous infusion for 20 minutes via a side hole endotracheal tube adapter, and the infants in the control group (n = 20) received 6 mL/kg air placebo. Results. Mean arterial-to-alveolar Po2 ratio values increased from 0.09 to 0.11 at 1 and 6 hours with a concomitant slight decrease in oxygenation index values from 23.7 to 19.7 at 1 hour and 20.7 at 6 hours after the first dose of surfactant. Oxygenation improved cumulatively after the second and third dose of surfactant, with mean arterial-to-alveolar Po2 ratios and oxygenation indices of 0.18 and 12.1 at 6 hours after the second dose of surfactant and 0.31 and 5.9 at 6 hours after the third dose of surfactant, eliminating the need for a fourth dose in any infant in the study group. After three doses of surfactant, persistent pulmonary hypertension had resolved in all but one of the infants in the study group versus none of the infants in the control group. No air leaks developed in any of the 20 infants in the study group after surfactant therapy, and only 1 infant required extracorporeal membrane oxygenation. Air leaks developed in 5 of the 20 infants in the control group, and 6 underwent extracorporeal poreal membrane oxygenation. The duration of mechanical ventilation, oxygen therapy, and admission was significantly shorter in the surfactant group than in the control group. Conclusion. Surfactant replacement therapy, if started within 6 hours after birth, improves oxygenation and reduces the incidence of air leaks, severity of pulmonary morbidity, and hospitalization time of term infants with MAS.
BACKGROUND. Initial ventilation strategy may play an important role in the development of bronchopulmonary dysplasia in very preterm infants. Early nasal continuous positive airway pressure is an accepted approach, but randomized clinical trials are lacking. Our aim was to determine whether early nasal continuous positive airway pressure, preceded by a sustained inflation, is more effective and less injurious in very preterm infants than conventional intervention.METHODS. Two hundred seven very preterm infants were assigned randomly in the delivery room to either a sustained inflation through a nasopharyngeal tube followed by early nasal continuous positive airway pressure (early functional residual capacity intervention) or repeated manual inflations with a self-inflating bag and mask followed by nasal continuous positive airway pressure, if necessary, after arrival at the NICU. The primary outcome measure was intubation <72 hours of age and bronchopulmonary dysplasia at 36 weeks was used as secondary outcome. This trial was registered as an early functional residual capacity intervention trial (ISRCTN 12757724).RESULTS. In the early functional residual capacity intervention group, fewer infants were intubated at 1 dose of surfactant, and the average duration of ventilatory support was less. Infants in the early functional residual capacity intervention group developed bronchopulmonary dysplasia less frequently.CONCLUSIONS. A sustained inflation followed by early nasal continuous positive airway pressure, delivered through a nasopharyngeal tube, is a more efficient strategy than repeated manual inflations with a self-inflating bag and mask followed by nasal continuous positive airway pressure on admission to the NICU.
1 February 2012 in American Journal of Obstetrics and Gynecology
To investigate the incidence and characteristics of cerebellar injury in a cohort of very preterm infants by using the mastoid fontanelle (MF) and posterior fontanelle (PF) approach in addition to routine cranial ultrasonography (US) through the anterior fontanelle (AF), with magnetic resonance (MR) imaging as the reference standard. The institutional review board approved this prospective study and informed consent was obtained. A cohort of 77 preterm infants (< 32 weeks) was examined with serial cranial US throughout the neonatal period by using the AF, PF, and MF views. MR imaging was performed around term-equivalent age in 59 of 77 infants. Sensitivity, specificity, positive predictive value, and negative predictive value of routine cranial US and cranial US with additional views were calculated. At cranial US performed through the MF, seven (9%) of 77 infants were identified to have posterior fossa hemorrhage. In only two of seven infants, the lesions were seen on routine AF views. The PF approach did not increase the detection rate of posterior fossa hemorrhage. MR images confirmed cranial US findings in all cases. MR images showed punctate hemorrhage in the cerebellum in six infants with normal cranial US findings. Among the 59 infants examined with both cranial US and MR imaging, cerebellar injury was diagnosed in 11 (19%). Cerebellar injury is a frequent finding in very preterm infants. Cranial US through the MF can demonstrate injury missed by using the routine AF approach. Punctate hemorrhagic lesions may remain undetected even when the MF approach is used; the prognostic implications of these smaller lesions need further attention.