Correlation of ominous fetal heart rate patterns and brain-specific creatine kinase

Creatine kinase isoenzyme analysis was performed on the cord blood of 125 infants who had undergone at least 30 minutes of intrapartum electronic fetal monitoring. The tracings were scored blindly according to severity of abnormal patterns, and the infants were grouped into ominous, intermediate, and normal scores. No differences were seen in creatine kinase MM or creatine kinase MB levels among the three groups. However, infants with ominous fetal heart rate patterns had higher creatine kinase BB levels and poorer outcome than infants with normal patterns.

Apnea associated with regurgitation in infants

To determine whether regurgitation might be a factor in the pathogenesis of apnea in certain infants, we compared the frequency of short and prolonged apnea immediately following regurgitation to that during control periods. Ten infants (nine preterm and one term) with histories of frequent regurgitation and also apneic spells were studied for 2 to 3 hours by monitoring nasal airflow, abdominal respiratory movements, electrocardiogram, pharyngeal pH, and pharyngeal pressure. In six of these infants additional observations were made without the intrapharyngeal recording devices. Fourty-four episodes of regurgitation were observed. Both prolonged apnea (P less than 0.05) and short apnea (P less than 0.01) occurred much more frequently during regurgitation than during the control period; however, the majority of prolonged apneic spells observed were unassociated with regurgitation. The increased frequency of apnea during regurgitation was not related to the presence of intrapharyngeal recording devices. Although nasal regurgitation was frequently associated with short apnea, no prolonged apnea was observed during the seven episodes of nasal regurgitation observed. The 14-fold increase in prolonged apnea frequency immediately following regurgitation supports the hypothesis for a causal relationship between apnea and regurgitation.

Spectral analysis of the EMG and diaphragmatic muscle fatigue during periodic breathing in infants

Periodic breathing occurs commonly in full-term and preterm infants. The mechanisms which switch breathing on and off within a cycle of periodic breathing are not certain. Since immature infants may experience diaphragmatic muscle fatigue, one potential switching mechanism is fatigue. Power spectra of the electromyogram, uncontaminated by the electrocardiograph artifact, were studied for evidence of diaphragmatic muscle fatigue during spontaneous periodic breathing in infants. A fall in the high-frequency (103-600 Hz) power and an increase in the low-frequency (23-47 Hz) power during periodic as compared with normal breathing would indicate fatigue. This effect was not observed in any of the infants studied. Hence, there is no evidence that periodic breathing is the result of diaphragmatic muscle fatigue. This finding suggests that the effect of drugs such as theophylline in eliminating periodic breathing may be unrelated to the fact that they also reduce fatigue.

Nonimmune hydrops fetalis--a rational attitude of management

A rational attitude of management of the nonimmune hydrops fetalis (NIHF) is stressed in order to achieve an optimal outcome of both the mother and the newborn. Of the two cases reported, both had an underlying cardiac condition. The first was due to rapid supraventricular tachyarrhythmia and responded favorably to intrauterine medication with digoxin and the subsequent delivery of a well baby. In the second case, cesarean section was performed unnecessarily for a fetal indication, since the hydropic infant died soon after birth from a severe cardiac malformation which was not unequivocally diagnosed prior to birth.

Neonatal cardiac output measurement using pulsed Doppler ultrasound

Recent developments in range-gated pulsed Doppler ultrasound velocimetry have offered a noninvasive technique for the quantitative measurement of blood flow and cardiac output that can be applied to the neonate and small infant. If used appropriately, pulsed Doppler ultrasound can be useful in clinical management of the ill neonate and can improve our understanding of cardiovascular physiology in both normal developmental and pathologic states.

Pediatric infections

The authors review the most commonly encountered and severe pediatric infections seen in the emergency room, concentrating on recognition and initial management of these infections.

Use of sodium nitroprusside in neonates: efficacy and safety

Sodium nitroprusside was administered to 58 neonates, including 11 with severe respiratory distress syndrome, 15 with persistent pulmonary hypertension of the newborn, 28 with clinical shock, three with systemic hypertension, and two with pulmonary hypoplasia, all refractory to conventional intensive therapy. Nitroprusside was infused at 0.2 to 6.0 micrograms/kg/min for periods of 10 minutes to 126 hours. Infants with severe respiratory distress syndrome had increased PaO2 and decreased PaCO2 or peak inspiratory pressure, and nearly all (82%) survived. Infants with persistent pulmonary hypertension of the newborn had variable responses; improvement did not correlate with survival, but survival (47%) was identical to that in an earlier series of infants given tolazoline. Infants in shock had improved perfusion, urine output, and serum bicarbonate levels, and these responses were significantly related to survival. Hypertension was controlled in all three hypertensive infants. Adverse effects were very uncommon. Toxic effects were not observed. Sodium nitroprusside is effective and can be used safely in circulatory disorders in the neonate.

Micromethod for bleeding time in the newborn

A new method of measuring bleeding time using an Autolet device is described. Normal ranges of bleeding time and volume of blood used in the test have been defined in a population including preterm babies. Abnormal values have been shown in newborns with a variety of problems, and an abnormality of bleeding time has been found to precede intraventricular haemorrhage.

Characterization of adenosine-induced respiratory depression in the preterm rabbit

The respiratory performance was studied after intraperitoneal administration of the adenosine agonists N6-phenyl-isopropyl-adenosine (PIA) and adenosine-5-ethylcarboxamide to preterm (gestational age 29-30 days) newborn halothane-anesthetized rabbits. Both agonists induced marked hypoventilation and irregular breathing by decreases in the breathing frequency as well as the tidal volume. Expiratory time was markedly prolonged, resulting in a decrease in the respiratory duty cycle (inspiratory time/total cycle duration). Analysis using the occluded-breath technique revealed that the adenosine analogues altered the time setting of the expiratory (inspiratory) neuronal circuits and lowered the inspiratory off-switch level, while inspiratory drive and the bulbopontine setting of the inspiratory phase were unaltered. The ventilatory response to CO2 was blunted after both adenosine analogues studied. Theophylline almost completely reversed the hypoventilation and irregular breathing seen after PIA injection. It is concluded that activation of central nervous adenosine receptors induced a marked respiratory depression in the preterm rabbit. Furthermore, our data imply that an overactivity of central adenosine mechanisms may have a pathophysiological significance for the irregular breathing or apnea of prematurity sometimes seen in the human neonate.

Carbonic acid dissociation constant (pK1) in critically ill newborns

In the Henderson-Hasselbalch equation, the apparent first dissociation constant for carbonic acid in plasma, pK1, is 6.10 +/- 0.01 (+/- SD) in healthy adults. In contrast, values for pK1 in sick adults and in sick infants and children have been reported to vary widely. Because of the far reaching implications of these findings, we repeated the measurements in 19 newborns in a neonatal intensive care unit. Two measurements were made in each infant, one while the infant was acutely ill and another after recovery. We found that neither the mean value nor the range of pK1 values was affected by the infants' clinical status. The values during the acute phase of the hospitalization (range, 6.01-6.12; mean +/- SD, 6.08 +/- 0.03) did not differ from those after recovery (6.02-6.17; 6.08 +/- 0.04). A second study was performed in order to see if the wide range of pK1 values seen in other studies might be the result of an unstable state accompanying acute changes in acid-base status similar to those that might be encountered in clinical situations. However, data in seven lambs showed no significant difference when pK1 before an acute alteration in acid-base status (6.10 +/- 0.04) was compared with that 10 min after (6.09 +/- 0.03). In newborn intensive care units, nomograms are used to calculate total CO2 from pH and PCO2 assuming a pK1 = 6.10. Our data support this practice.

Prolonged effects of maternal alcohol ingestion on the neonatal electroencephalogram

Newborn infants of mothers who drink heavily (greater than 2 oz alcohol per day) during pregnancy have been shown to have hypersynchrony of the EEG. The possibility that hypersynchrony is related to acute alcohol withdrawal was tested. Eleven preterm infants of mothers who drank heavily ("alcoholic") were studied at a postnatal age of 4 to 6 weeks using power spectral analysis of EEG signals. This group was compared with a control group with similar racial and socioeconomic status. In addition, a group of ten "healthy" preterm infants was compared with a carefully matched control group. Total power of the EEG during quiet, indeterminate and rapid eye movement (REM) sleep was 162%, 183%, and 188%, respectively, in the infants whose mothers were alcoholic when compared with their control infants or with the healthy preterm infants and their control infants. It is concluded that ingestion of alcohol during pregnancy may result in potentially serious prolonged effects on brain function of the offspring, even in the absence of dysmorphology.

Use of glycosylated hemoglobin as a screen for macrosomia in gestational diabetes

Glycosylated hemoglobin and blood sugar levels in the fasting state and two hours after oral 100 g glucose load were measured in 180 patients. Glycosylated hemoglobin was measured by cation exchange column chromatography, and blood sugar was measured by hexokinase reaction. Patients with an elevated postprandial and/or fasting blood sugar level (positive screen) subsequently underwent three-hour glucose tolerance test. The mean value of glycosylated hemoglobin in patients with a negative screen and normal hemoglobin was 6.17 +/- 0.61%; and the value for glycosylated hemoglobin in patients with class A diabetes and normal hemoglobin electrophoresis was 6.85 +/- 0.73% (P less than .001). A glycosylated hemoglobin value greater than 6.78 (mean + 1 SD) was considered elevated. Glycosylated hemoglobin values were elevated in 21 of 33 patients with gestational diabetes and in 27 of 147 patients with normal blood sugar levels. The sensitivity and specificity of glycosylated hemoglobin for the diagnosis of gestational diabetes were 63.6 and 81.6%, respectively. Fifty percent of patients with an initially elevated glycosylated hemoglobin value delivered macrosomic infants, whereas no patient with a normal glycosylated hemoglobin value had a macrosomic infant. An elevated glycosylated hemoglobin value may alert the obstetrician of a potentially elevated mean blood sugar level and may warrant aggressive management of gestational diabetes.

Congenital failure of hematopoiesis in the newborn infant

Hematopoietic stem cell cultures have greatly advanced our understanding of the physiology of blood production at its early stages and have facilitated the study of various factors that regulate cell differentiation and proliferation. With this understanding, the author discusses hematopoiesis, hematopoietic stem cells and assays for their study, and hematopoietic failure. This is followed by a discussion of different forms of bone marrow failure and guidelines for a rational basis for their therapy.

Clinical spectrum of neonatal apnoea in very low birthweight infants

This study quantifies apnoea and assesses the response to xanthine derivatives amongst 172 consecutively born, surviving very low birth weight (VLBW) infants, 136 appropriate weight for gestational age (AGA), 36 small for gestational age (SGA). All babies had electronic monitoring of heart and respiratory rates and nursing staff recorded episodes of apnoea (greater than 10 s), bradycardia (less than 100) and cyanosis. Only 42 (24.2%) babies had no episodes recorded. (25 AGA, 17 SGA). Sixty-four (37.2%) received active resuscitation on at least one occasion with six babies ventilated by bag and mask on more than 10 occasions. Apnoea had commenced by day 10 of life in all the babies who had apnoea and persisted beyond day 50 in only six; however four of these infants were still requiring active resuscitation. Apnoea had ceased by 37 weeks post-conceptual age in 88% and by 40 weeks in all but three babies. Risk factor analysis revealed a strong correlation (P less than 0.005) with lower gestational ages and birth weights, respiratory distress syndrome (RDS) and the problems associated with it, such as mechanical ventilation, patency of the ductus arteriosus (PDA) and chronic neonatal lung disease. A single, reversible cause for apnoea was rarely demonstrated. Care must be exercised with feeding, physiotherapy and suctioning the pharynx and trachea of 'at risk' infants. Xanthine derivatives were highly effective in decreasing the frequency of recurrent apnoea from a mean of 10.08 episodes one day before, to 1.83 two days after commencement of treatment.

Subclinical delta status in the newborn--an unfavorable prognostic sign

A hitherto undescribed, unusual EEG abnormality invariably associated with a poor prognosis was reported and was called subclinical delta status. It consisted of continuous discharges of high voltage monomorphic or polymorphic delta activity occurring diffusely but often asynchronously in all leads, without sleep cycles. These discharges when monomorphic may be confused with respiratory artefacts, and when polymorphic they may be mistaken for part of the background activity. Four neonates with this abnormality all had intracranial bleeding and were mechanically ventilated because of frequent apneic attacks. Staring or deviation of the eyes was frequently observed during the EEG recording. A small dose of intravenous diazepam temporarily abolished this activity. Three infants died and the other survived with neurological sequelae.