Cardiac asystoles in preterm infants: are these a risk factor for SIDS? - abstract

In spite of significant advances in perinatal/neonatal care, preterm infants remain at high risk for unexplained death in infancy. Using continous documented monitoring as a predischarge screen for persistance of apneas and bradycardias in preterm infants (mean GA 30.5 weeks) prior to hospital discharge, 21 of 332 infants (6.3 per cent) had asystolic events defined as cardiac pauses > 3 seconds. All affected infants had a history of O2 desaturation < 85 per cent and/or colour change in the weeks prior to event monitor screening. Concurrent 72-hour Holter monitoring confirmed sinus pauses of 3 - 10 seconds. Echocardiogram revealed pulmonary artery branch stenosis in 9 of the 21 infants, but no other structural abnormalities. Gastroesophageal reflux was diagnosed by pH probe and/or Milk-Scan in all 21 infants; clinical symptoms improved after specific therapy but asystoles and bradycardias persisted. All infants were followed with home monitoring until asystole-free for 2 months. Asystoles decreased with age: with a mean of 33.7 events/wk at 36 wks post-conceptional age, 24.7 at 47 wks and only 1 infant had asystolic events beyond 58 weeks. Pacemakers were recommended in 3 infants, but only placed in one. None of the infants died. Conclusion: asystolic events occur in preterm infants without significant anatomical cardiac abnormalities and can be diagnosed by continuous documented monitoring. Resolution occurs spontaneously, but long-term cardiology follow-up is necessary to determine later outcome and complications. The significance of these events and their relationship to sudden death in infancy need to be explored (AU)

True apenas as a first symptom of viral upper respiratory tract infection in preterm infants on home documented event monitors - abstract

Between January, 1992 and September, 1994 all preterm infants followed in the Neonatal High-risk Follow-up Clinic were prospectively evaluated for apneas and/or bradycardias associated with upper respiratory tract infection (URI). 52 infants (mean post-conceptional age 39.2 weeks) had increased apneas with URI. All infants had nasal stuffiness; dry cough was present in 10 (19 percent) and 12 (23 percent) had low grade fever, 16 (31 percent) slept more and had to be awakened for feeds. Respiratory syncytial virus (RSV) antigen was negative in 40; 12 were RSV positive. All bacterial cultures were negative. Hospitalization was necessary in 23 infants (5 with RSV and 19 without RSV). The 9 infants on xanthine therapy had therapeutic levels. The onset of apneas and bradycardias was abrupt, apneas (by report and monitor data) preceded parental suspicion of URI. Monitor data showed 0-5 apneas > 20 sec. per during URI. In addition, 22 percent of infants demonstrated bradycardias with heart rates < 80 minute with URI. Continous pulse oximetry on hospitalized infants showed baseline levels of 93-98 percent with frequent desaturations as low as 78 percent, requiring O 2 supplementation in 14 infants and Xanthine therapy in 16. None of the infants expired. Ex-preterm infants on home monitoring for persistence of apnea of prematurity may be at a high risk for severe apneas and bradycardias with viral upper respiratory infection, and require close surveillance whenever exposed. The relationship of this to SIDS/ALTE needs to be investigated (AU)

Newer methods of managing respiratory failure in the newborn - abstract

In spite of the technological advances in neonatal ventilation support over the past two decades, about 30-40 percent of term newborns with severe meconium aspiration syndrome (MAS) and/or persistent pulmonary hypertension of the newborn, succumb in spite of aggressive ventilatory management. The use of Extracorporeal Membrane Oxygenation (ECMO) for infants with severe MAS or PPHN in intractable respiratory failure has significantly changed their outcome. Criteria for placing infants on ECMO included: A) Acute deterioration pa0[2] <50 (AaD02 > 630) x 2 hours or pH <7.15 x 2 hours; or B) Lack of Improvement pa0[2] <60 (AaD0>620) x 8 hours pH <7.2 x 8 hours. Mean ventilation settings prior to initiation of ECMO. Fc0[2] 1.0 Inv 101ñ22.7 PIP 46.8ñq.9 PEEP 4.5ñ1.6 with mean blood gases pH 7.38ñ0.21 Pa0[2] 34.5ñ14.5 Pc0[2] 41.5ñ19.8. Between February 1986 and October 1987, 55 infants were placed on ECMO for a mean time of 84.3ñ47.8 hours. Fifty-three (96.3 percent) infants survived the procedure and were successfully decannulated, 4 infants expired after coming off ECMO support, leaving an overall survival rate of 89.1 percent (AU)