The cardiothoracic ratio in AGA and SGA very low birth weight newborn infants.

BACKGROUND: Cardiothoracic (CT) ratio is a common measurement used to assess heart size in chest radiographs of pediatric patients, but no recent studies have analyzed the standards for CT ratios in very low birth weight (VLBW) infants. OBJECTIVE: The aim of this study was to provide improved standards for CT ratios measured from chest radiographs of VLBW (<1500 g) infants, and to compare CT ratios between small for gestational age (SGA) and appropriate for gestational age (AGA) infants in this population. DESIGN/METHODS: Among VLBW infants admitted to the Jacobi Medical Center NICU from 2002 to 2004, CT ratios were calculated from anteroposterior supine chest radiographs taken of 54 VLBW infants (18 SGA and 36 AGA group-matched on the basis of birthweight and sex) during the first 24 h of life. RESULTS: There were no significant differences between the two groups with respect to birthweight, sex, 1-min Apgar score, 5-min Apgar score, intubation status and degree of inspiration. Median GA of the SGA infants was significantly greater than the AGA infants (30 and 27 weeks, respectively; P<0.001). CT ratios among SGA infants were significantly larger than those among AGAs. Using the widest internal width of the bony thorax, the mean CT ratio among SGA and AGA infants was 0.523 and 0.479, respectively (P=0.00102). CONCLUSIONS: VLBW SGA infants have larger CT ratios than VLBW AGA infants, suggesting that existing standards for normal CT ratios may be inappropriate for use among SGA infants.

The effects of intrauterine cocaine exposure on the respiratory status of the very low birth weight infant.

OBJECTIVES: This study examined the effects of intrauterine cocaine exposure on very low birth weight infants with respect to their surfactant requirement and need for ventilatory support. STUDY DESIGN: A retrospective cohort study was conducted on infants with birth weight between 750 and 1500 g admitted to the neonatal intensive care unit between January 1992 and January 1995. RESULTS: Of the 149 infants studied, 48 infants were exposed only to cocaine and 101 infants had no drug exposure. There were no significant differences between the two groups for gestational age, sex, abruptio placenta, prolonged rupture of membranes, and antenatal steroid usage. The cocaine-exposed group had a significantly greater birth weight (1190 vs. 1109, p<0.02), less prenatal care (48% vs. 14%, p<0.00007), older maternal age (30 vs. 24, p<0.00002), more black race (79% vs. 57%, p<0.01), and more rapid plasma reagin (RPR) positivity (25% vs. 2%, p<0.00006). There were no significant differences in median APGAR scores, or incidence of necrotizing enterocolitis, retinopathy of prematurity (ROP), intraventricular hemorrhage (IVH), and bronchopulmonary dysplasia (BPD) between the two groups. Cocaine-exposed infants received surfactant treatment less often (73% vs. 48%, p<0.0035), received fewer mean doses of surfactant (0.4 vs. 10.0, p<0.0014), and were intubated less frequently (44% vs. 65%, p<0.012). There was no significant difference between groups for intubation at 24 and 48 hours and for the development of bronchopulmonary dysplasia. CONCLUSION: Perinatal cocaine exposure appears to have some significant short-term effects on the need for surfactant replacement therapy and need for initial intubation in respiratory distress syndrome (RDS) but no overall effect on the development of BPD.

Aerosolized pentamidine for prophylaxis of Pneumocystis carinii pneumonia in infants with human immunodeficiency virus infection.

Aerosolized pentamidine is widely used in adult patients with human immunodeficiency virus as both prophylaxis and therapy for Pneumocystis carinii pneumonia. The aim of this study was to evaluate the safety of a monthly regimen of aerosolized pentamidine in human immunodeficiency virus-infected infants. Seven human immunodeficiency virus-infected infants, ages 3.5 to 11 months, were given a total of 45 monthly treatments of aerosolized pentamidine. The infant's dose of pentamidine was based on an adult dosage of 300 to 600 mg/month, adjusted for minute ventilation and weight. There were no discernible clinical side effects in 62% (28 of 45) of the treatments. Observed toxicity included mild to moderate coughing, mild wheeze and transient arterial desaturation as measured by pulse oximetry. Pulmonary function data revealed an increased tidal volume (P < 0.005) and an increased pulmonary resistance (P < 0.02) post-pentamidine treatment. Urinary pentamidine concentrations were obtained and pentamidine was detected in all tested samples suggesting pulmonary deposition and systemic absorption. In conclusion aerosolized pentamidine appears to be a relatively safe, well-tolerated treatment in infants, with side effects similar to those seen in adults.

Human immunodeficiency virus seropositivity in critically ill neonates in the south Bronx.

Cord blood was anonymously screened to determine the prevalence of human immunodeficiency virus (HIV) seropositivity in neonates admitted to the neonatal intensive care unit (NICU) at the Bronx Lebanon Hospital Center, located in the South Bronx. We speculated that factors leading to admission to the NICU such as low birth weight, prematurity and being small for gestational age would also be associated with an increased prevalence of HIV seropositivity. During the study period the prevalence of HIV seropositivity was 11.6% in the NICU population. There was no significant difference in maternal age, gravidity, race and sex in HIV-seropositive vs. HIV-seronegative newborns. There was a significantly increased incidence of maternal drug use (P less than 0.01), babies small for gestational age (P less than 0.005) and microcephaly (P less than 0.02) in seropositive vs. seronegative NICU babies. The results of this study suggest that the NICU population may comprise a significant number of infants of HIV-infected mothers.

Ventilation-perfusion abnormalities in the preterm infant with hyaline membrane disease: a two-compartment model of the neonatal lung.

Arterial-alveolar differences for oxygen, carbon dioxide, and nitrogen were measured in 7 non-distressed preterm infants and 21 ventilator-dependent preterm infants with hyaline membrane disease. The preterm infants with hyaline membrane disease had a significantly lower average arterial pH (7.34 vs. 7.44; P less than 0.001), and significantly higher arterial-alveolar differences for oxygen (286 mm Hg vs. 34 mm Hg; P less than 0.005) and nitrogen (118 mm Hg vs. 7 mm Hg; P less than 0.005). Both groups had elevated arterial-alveolar differences for PCO2 (9 mm Hg in infants with hyaline membrane disease, 5 mm Hg in nondistressed infants; P less than 0.2). When acute changes in mean airway pressure were produced in 14 distressed infants, arterial-alveolar CO2 and N2 differences moved in opposite directions in 11 infants. This observation suggests that changes in mean airway pressure do not acutely recruit atelectatic alveoli, but cause redistribution of ventilation within alveoli already ventilated.

Discrepancies between transcutaneous and end-tidal carbon dioxide monitoring in the critically ill neonate with respiratory distress syndrome.

PaCO2, transcutaneous PCO2 (PtcCO2), and end-tidal PCO2 (PetCO2) measurements were studied in 12 critically ill neonates. PtcCO2 was measured using a combination CO2/O2 sensor during the routine care of these patients. End-tidal sidestream sampling was performed during blood gas measurement as dictated by the patient's clinical condition. There was a linear correlation between PtcCO2 and PaCO2 (n = 51, r = .71, slope = 0.90). PetCO2 and PaCO2 did not correlate as well (n = 51, r = .52, slope = 0.42). Acidosis negatively affected the correlation between PtcCO2 and PaCO2. When pH was greater than 7.30, r = .75 and slope = 1.28 (n = 38), whereas when pH was less than 7.30, r = .62 and slope = 0.73 (n = 13). The presence or absence of a metabolic acidosis did not have a significant effect on the slopes obtained. PtcCO2 monitoring using combined sensors is a useful and practical means of monitoring in the neonatal ICU, although acidosis affects the ability to correlate transcutaneous and arterial values. End-tidal sidestream measurements are not as clinically useful because they vary due to different ventilation/perfusion relationships in the sick neonate.