Nap studies underestimate the incidence of gastroesophageal reflux.

Shorter nap (1 and 4 hr) pH studies inaccurately diagnosed gastroesophageal reflux (GER) in a group of infants evaluated for apparent life threatening events (ALTE) and recurrent apnea. Twenty-five infants with a postconceptional age of 42 +/- 8 SD weeks, were evaluated by 12-hr polysomnography (PSG). Prior to the start of the 12-hr study, a 1-hr Tuttle Test was performed. By means of the 12-hr study 11 infants were diagnosed as having GER while the Tuttle Test incorrectly diagnosed 6 infants, 5 as having no GER and 1 as having GER when no GER was present (P < 0.05). No differences in the amount of periodic breathing (PB) or apnea density (AD) were found between the two studies. In addition, the first 4 hr of the 12-hr PSG segment following the first feeding was evaluated separately. In the 4-hr segment, two of the infants were incorrectly diagnosed as not having GER. In this study, nap studies failed to diagnose all of the infants with GER. Therefore, we conclude that an infant cannot be accurately diagnosed as not having GER without prolonged pH recording.

Sudden infant death syndrome: an overview.

The diagnosis of sudden infant death syndrome (SIDS) depends on a thorough and complete autopsy. Many of the infants who die of SIDS have common findings. There are certain steps to be taken for prevention and diagnosis of SIDS. Further investigation of this syndrome still is necessary.

Compliance measurement in respiratory distress syndrome: the prediction of outcome.

Dynamic compliance (Cdyn) measurements within the first three days of life predicted survival in 60 preterm infants suffering from respiratory distress syndrome. Cdyn was measured in 47 survivors at 2.3 +/- 1.4 days of life and in 13 nonsurvivors on 2.7 +/- 1.7 days. All nonsurvivors died from respiratory failure within the first two weeks of life. Mean Cdyn of the survivors was 0.83 +/- 0.33 ml/cm H2O and of the nonsurvivors 0.35 +/- 0.19 ml/cm H2O (p less than 0.001). Cdyn values below 0.45 ml/cm H2O predicted 11 of 13 deaths in infants, and Cdyn measurements above this value predicted 45 of 47 survivals, with a specificity of 81% and a sensitivity of 89%. Eleven of the survivors, who subsequently developed bronchopulmonary dysplasia (BPD), had a mean Cdyn of 0.56 +/- 0.23 ml/cm H2O. When these infants were matched with infants of comparable weight without evidence of BPD, the BPD group had a significantly lower Cdyn (p less than 0.05). Cdyn measurements during the first three days of life are useful in predicting outcome of respiratory failure secondary to respiratory distress syndrome.

Ventilatory responses to carbon dioxide in infants at risk for sudden infant death syndrome.

We examined the ventilatory response to inhaled CO2 in 77 infants at postconceptional ages ranging from 31 to 50 wk, 43 of whom were also evaluated with a 12-h pneumocardiogram (PCG). Infants were tested after sedation with chloral hydrate, and monitored with ECG and transcutaneous oxygen and CO2 monitors. Sleep state was evaluated by visual inspection of the infant's behavior. Among the 43 infants examined with the PCG, 22 had abnormal PCGs. Of these, 27% had significantly (p less than .05) abnormal CO2 response slopes, compared to 9% of those with normal PCGs. Breathing frequency did not change after CO2 inhalation in 82% of the abnormal PCG and in 33% of the normal PCG groups.