Thyroid function in healthy Thai neonates.

OBJECTIVES: To construct a normative data for serum thyroxine (T4), free T4 (FT4), triiodothyronine (T3) and thyrotropin (TSH) in Thai neonates. STUDY DESIGN: A cross-sectional study of 275 healthy full-term neonates was conducted. Blood samples were obtained from umbilical cords of the neonates and from heel pads of infants aged 1-30 days. Hormone measurements included serum T4, FT4, T3 and TSH. RESULTS: Mean serum T4 and FT4 levels rapidly increased after delivery to the maximum level at 1-3 days of age. Thereafter, they declined to a steady state level within 2-4 weeks. Mean serum T3 level was very low at birth. The concentration increased 3-5 times and reached a steady state levels within 1 week. In contrast, mean serum TSH declined from birth and the level at 1-3 days of age was slightly less than that of the cord blood. It changed little after 3 days of age. Previous studies have shown a transient TSH surge in the first 24-48 hour of life. TSH surge was not apparent in our study because samples were not obtained from infants < 24 hours old. Therefore, if TSH is measured for screening of congenital hypothyroidism, samples should be obtained from umbilical cord or infants aged > 48 hours. CONCLUSIONS: This study provides the normative data for thyroid function tests in Thai full-term neonates. These data are useful for detection and verification of hypothyroidism in a screening program for congenital hypothyroidism.

Neonatal polycythemia: effects of partial exchange transfusion using fresh frozen plasma, Haemaccel and normal saline.

BACKGROUND: Neonatal polycythemia remains a significant clinical problem in Thailand. Partial exchanges transfusion (PET) with fresh frozen plasma (FFP) has been the mainstay of management for this condition in Thailand. Since FFP is difficult to find in certain areas and can cause concerns of transfusion related diseases, this study was undertaken to investigate the possibility of using plasma substitute and normal saline (NSS) for PET in the newborn infant with polycythemia. OBJECTIVE: 1. To compare the rate and duration of decrease of venous hematocrit (Hct) before and after PET with FFP, Haemaccel and NSS. 2. To compare any complications from using FFP, Haemaccel and NSS such as coagulation defect, electrolytes change, etc. in PET. METHODS AND SUBJECTS: A randomized prospective trial was conducted in Neonatal Unit, Department of Pediatrics, Ramathibodi Hospital. The first phase of study: July 1, 1993 to June 30, 1994: randomized prospective trial using FFP or Haemaccel for PET in 26 newborn infants with polycythemia. The second phase of study: July 1, 1994 to June 30, 1995: consecutive enrollment trial using NSS for PET in 38 consecutive newborn infants with polycythemia. RESULTS: There was significant decrease in Hct in both groups after PET but there was no statistically significant difference in the rate of decrease of Hct. There was no significant difference in biochemical profiles in both groups of infants 24 hours after PET. In the NSS group, there was significant decrease of Hct level after PET. There was no significant change of biochemical profiles and coagulation activity in these patients 24 hours after exchange transfusion. There were 2 patients with complications related to umbilical venous catheter and PET. CONCLUSION: Haemaccel and NSS can be safely used for PET to treat neonatal polycythemia. However, the attending physician should be aware of possible complications related to umbilical venous catheterization and PET.

Indomethacin prophylaxis for patent ductus arteriosus (PDA) in infants with a birth weight of less than 1250 grams.

BACKGROUND: Very low birth weight (VLBW, less than 1500 g) and extremely low birth weight infants (ELBW, less than 1000 g) are the premature infants that are most likely to develop symptomatic PDA. Intravenous indomethacin has proven effective in prevention of PDA in many prospective trials. This strategy will be a useful adjunctive therapy for premature infants in Thailand. OBJECTIVE: To answer the following questions: 1. Will multiple doses of intravenous indomethacin, given to VLBW infants within the first day of life, effectively prevent the occurrence of symptomatic PDA? Are there any side effects or complications? 2. Will this strategy be more beneficial in ELBW? METHODS AND SUBJECTS: The study included thirty VLBW infants born at Ramathibodi Hospital, with birth weights ranging from 630 to 1230 g. They were randomized into 2 groups of 15 infants each. One group received 3 doses of intravenous indomethacin at the dosage of 0.2 mg/kg initially and then 0.1 mg/kg every 12 hours for 2 more doses; the second group received a placebo. The study was performed by a double blind control. RESULTS: Sixteen infants developed symptomatic PDA, 4 in the indomethacin group and 12 in the placebo group. The decrease in incidence of PDA is statistically significant. But when the data was analyzed separately for the VLBW and ELBW groups. The effects were only significantly different in ELBW but not yet significant in the VLBW group. There was a statistically significant difference in the incidence of severe intraventricular hemorrhage (IVH) (grade 3 or higher) in the ELBW infants. CONCLUSION: Intravenous indomethacin therapy given to VLBW infants with a birth weight of less than 1250 g decreased incidence of symptomatic PDA with no significant permanent side effects. The effect was markedly noticeable in ELBW infants. Incidence of severe IVH was also markedly decreased in the ELBW infants who received indomethacin.