Poor response to surfactant therapy in RDS-infant with early patent ductus arteriosus.

A prospective study was conducted to evaluate the effect (Alvofact by Boehringer Ingelheim) on oxygen and mean airway pressure (MAP) requirements and improvements in the alveolar-arterial partial pressure of oxygen gradient (A-a PO2 gradient) in 32 preterm infants with respiratory distress syndrome (RDS), 16 infants in each group. The diagnosis of PDA was made in the presence of hyperactive precordium and/or a systolic murmur heard at upper left sternal border and confirmed by echocardiography when available, or by autopsy. The mean birthweight (1180 vs 1079 g,p=0.35) and the mean age at receiving surfactant (5.5hr vs 7.8hr, p 0.234) of the two groups were not statistically different but the initial severity of RDS in infants with early PDA (Group 1) was more. In Group 1, improvements in oxygen requirements were significant at 1 hr after treatment (p=0.01) but became nonsiginificant at 24 hours (p=.06). Sustained improvements in A-a PO2 gradient were found at 48 hrs (p=0.012). Improvements in MAP were significant at day 14 after treatment (p=0.03). In infants without early PDA (Group 2), improvements in oxygen requirement were significant at 30 min after treatment (p=0.027). Improvements in MAP and A-a PO2 gradient were significant at 5 min after treatment. Improvements in A-a PO2 gradient appeared nonsignificant at 48 and 72 hours when PDA was present and subsequently appeared significant again at 96 hours when PDA was closed by indomethacin. Mortality was significantly reduced (11 vs 2, p=0.003) in Group 2. Because only 9 infants in Group 1 lived longer than 28 days trends suggested a lower incidence of bronchpulmonary dysplasia in Group 2 (7 in 9 vs 5 in 14, p=0.083). In conclusion, RDS-infants with PDA prior to surfactant therepy have poor and transient responses to surfactant and were associated with higher mortality and higher incidence of brochopulmonary dysplasia. Early closure of PDA may benefit these infants.

Measurements of the irradiance and the effect on environmental temperature of the Siriraj phototherapy lamp.

The Siriraj Phototherapy Lamp (SPL) was invented by the investigator to compensate for a similar, but expensive imported device and h low-efficiency locally-made device. The SPL irradiance and effect on environmental temperature were measured in this study. The device used six fluorescent bulbs of which zero to three were blue. The distance between the bulbs and the mattress was fully adjustable. The blue fluorescent bulb emitted a higher light intensity than the white. In both kinds of bulbs the intensity of light was higher in the center of the bulbs than at the periphery. The light intensity varied proportionately with the number of blue fluorescent bulbs, but inversely with the distance between the bulbs and the mattress. Lining the SPL with a white cloth increased the light intensity. This inverse relationship was also found between the environmental temperature near the mattress and the distance. Placing a plastic shield under the SPL reduced the radiant heat emitted by the bulbs to the mattress which resulted in a decrease of environmental temperatures by 2.3oC and 3.0oC at the distances of 45 and 30 cm, respectively.

Thermal effects of covering the single-wall infant incubator with a Blanket.

A cross-over study was conducted on the changes in the wall and air temperatures of the single-wall infant incubator, as well as infant abdominal skin and rectal temperatures, when the incubator is covered a blanket. Sixteen clinically stable infants being nursed in incubators, nine males and seven females with a mean birth weight of 1,905 g (rang 1,100 to 3,100 g) and a mean age at the time of study of 17.6 days (range 3 to 48 days), were randomly assigned to two orders of study conditions. Significant temperature increases were recorded when the incubator were covered, compared with periods without a blanket : 0.62oC for the abdominal skin incubator wall (p = 0.000); 0.57oC for the air temperature (p = 0.001); 0.11oC for the abdominal skin temperature (p = 0.002); and 0.12oC for the rectal temperature (p = 0.000). The study showed that covering the single-wall infant incubator with a blanket can prevent the incubator wall from heat loss by natural and forced convection, and the infant from heat loss by natural convection and radiation.