R S Pildes

Failure of phototherapy to reduce serum bilirubin in newborn infants

P H o T O T H ~. g A V Y is effective in lowering the serum bi l i rubln concentra t ion in many low-bir th-weight infants wi th physiologic or id iopa th ic j a u n d i c e ? -~ Serum bi l i rubin values may be decreased in both Caucas ian and Negro newborn in fan t sJ Pho to the rapy has also been repor ted to lower serum bi l i rubin concentrat ions in hemolyt ic disease due to A B O incompat ibi l i ty . 7 T h e purpose of this repor t is to call attent ion to a group of newborn infants who d id not show a significant clinical response to pho to the rapy and were therefore considered pho to the rapy failures. As this was no t a control led study, r igid cr i ter ia were not used to de te rmine the ind ica t ion for photo therapy. I n general , the decision was based on the clinical history, serum bi l i rubin values above 12 rag. pe r 100 ml., and ind iv idua l evaluat ion of each patient, F ive infants, born a t Cook County Hospi ta l , were exposed to eight 40 wa t t b lue fluorescent lights, 5 and 3 infants, born at Univers i ty of Ill inois Hospi ta l , were exposed to eight 20 wa t t Vi ta l i te f luorescent lights. Pho to the rapy was in t e rmi t t en t as previously repor ted. 5

Plasma glucose changes in preterm infants during oral theophylline therapy.

no longer available, reabsorption of the reconverted bilirubin would presumably occur; this might account for the marked rebound observed in the three infants requiring repeat phototherapy. It is difficult, however, to explain the less pronounced rebound that occurred in the two infants in the post-phototherapy period; perhaps the increasing maturity of the liver, with improved conjugation, is a factor in reducing the post-phototherapy rebound. In the infants with low intestinal obstruction, the response to phototherapy and the subsequent rebound were hardly different from that of infants without obstruction. 6 The propulsion of photoisomers into the large gut might again be a significant factor in determining this particular form of response.

Plasma amino acids in low-birth-weight infants treated with intravenous amino acid infusion.

Concentrations of plasma amino acids were determined using a ‘semimicro’ method with ion exchange chromatography in low-birth-weight infants with or without intravenous amino acid infusion. There were

130 ECHOCARDIOGRAPHY (ECHO) STUDIES IN INFANTS OF DIABETIC MOTHERS (IDM)

Abnormal cardiac findings detected by echo in IDM have been emphasized but there is scant information of incidence, severity or pathogenesis. Thus, a prospective controlled study of 30 IDM and concurrent 36 normal newborns (N) was undertaken. There were no significant differences in mean ±S.E. birth wt. or gest. age of the IDM (3590±125g, 36.9±1.6 wk) compared to N (3383±899g, 39. 6±3.7wk). There were 17 Class A, 13 insulin dependent IDM. Respiratory distress (RDS) was seen in 9, hypoglycemia (H) in 9 and polycythemia (P) in 9 IDM. Echos (85) were done at 24-72 hr and/or 5-7 d. Findings at 24-72 hr. are listed:Left vent. function, estimated from % shortening (ΔD) of LVD was depressed *p<.01 in IDM but were similar to N(26.8±1.3 vs 27. 9±1.4 respectively)at 5-7 d . No differences were seen between IDM and N in any of the other factors including LV-PEP or RV-PEP. Class of diabetes, RDS, H or P did not influence echo findings. Thus, echo abnormalities were limited to transient and mild depression of LV function as judged by % shortening.

1483 FUROSEMIDE (F) ANTAGONISM OF INDOMETHACIN (I) EFFECT ON RENAL FUNCTION

To evaluate if (F) would prevent the adverse renal effects of I.V.(I), 9 premature infants with PDA were randomized into 2 groups; 4 received 1(0.3mg/kg) alone and 5, I and F (lmg/kg I.V.) simultaneously. There were no slg. differences between the groups in B.W.(mean±S.D, 1179±456 vs 1021±282gm), gest,age(31.3±2.2 vs 29.5±1.9wks), postn. age (9.0±2.9 vs 11.6±0.5d.), clinical cardiovascular status, pH, F102, pO2 and pCO2.Three in I and 4 in I+F responded with closure of PDA. There were no sig. differences in renal function between the groups. However, when compared with baseline, sig. decreases in urine output, GFR and C-H2O were seen when I was used alone but not when I+F were given simultaneously. The addition of F did not affect FeNa. These changes suggest that F may be useful in preventing oliguria by overriding the action of I.

1358 BLUE LIGHT (BL) VS. WHITE LIGHT (WL) ON BILIRUBIN PHOTODEGEADATION (PD) IN VITRO

BL is considered more efficient than WL in bilirubin PD because of the greater energy output at the λ of maximal absorption for bilirubin. However, bilirubin PD using BL and WL with similar irradiance (I) has not been studied. Since PD is dose related to I in vivo, it was hypothesized that BL and WL with similar I should have the same effect on bilirubin PD. Olympic bili-lites were used with 8-20W duro-test vita-lite for WL and 8-20W F20T12/BB for BL. Sealed heparinized microhematocrit tubes with pre-exchange plasma samples were placed under light with I varying from 0.9-10.2 μw/cm2/nm for 4 hrs. I was measured in the range of 425-475 nm using the Olympic bilimeter. The pH, albumin, and temp. of the samples under both light sources were similar. The % PD of bilirubin is shown below. The mean I in comparison groups was the same.This study indicates that WL with similar I as BL is more effective at lower I in bilirubin PD. These findings suggest that wavelengths other than those found in BL also contribute to bilirubin PD.

990 HYPERGLYCEMIA IN STRESSED SMALL PREMATURES

The metabolic responses to a constant glucose infusion (4.3±.2 mg/kg/min) were measured in 30 prematures, 700-1559g. The study included 18 stressed infants who needed assisted ventilation (Grp A) and 12 controls (Grp B). Plasma samples for glucose, insulin, cortisol, and glycerol were obtained from cord blood, just prior to glucose infusion at 2.1±.2 hr (mean ± S.E.) and 5.5±.4 and 25.6±1.0 hr after start of glucose infusion. Metabolic responses were similar in both groups in the cord and preinfusion samples. In the first post-infusion sample, glucose (p<.01), cortisol (p<.05), and glycerol (p<.01) were higher in A than in B. Insulin values correlated with glucose values (p<.001) and I/G were not significantly different between A and B. Hyperglycemia (plasma glucose >145mg/dl) was seen in 10 of A and 1 of B infants (p<.025). Infants in A who became hyperglycemic in the first post-infusion sample (Grp A1) were then compared with stressed euglycemic infants (Grp A2). Insulin levels were higher (42.2±13.9 VS 9.4±2.5μU/ml, p<.05), glycerol levels similar (8.6±1.6 VS 8.8±1.4mg/dl), but cortisol levels lower (15.3±4.2 VS 28.0±2.4μg/dl, p<.05) in A1 than A2 infants. There was no difference in mortality between A1 and A2 infants; stress, rather than hyperglycemia was related to mortality. In summary, cortisol and glycerol responses were higher in stressed neonates. However, hyperglycemia in stressed infants could not be attributed to any of the metabolic factors evaluated.

1038 REDUCTION OF INSENSIBLE WATER LOSS (IWL) IN PREMATURES UNDER RADIANT WARMERS

Excessive IWL is a well known complication in prematures placed under radiant warmers. A controlled study was therefore undertaken to determine if a plastic dome would be useful in minimizing IWL. Twenty-nine AGA healthy infants with gest. age of 30.9±0.4 wks (mean±S.E.) birth wt. 1.4±.03kg and postnatal age of 8.7±2.1 days were studied. IWL was determined from insensible wt. loss measured on a Potter Bed Balance scale. Water losses from urine and stool were prevented by attaching a plastic pouch to the perineum. IWL was measured under 2 conditions in the same infant: with heat shield (Grp A) and without heat shield (Grp B). Each study period extended for 3 hrs after 30 min. of stabilization. The studies were done in an infra-red radiant warmer (Ohio) with servo-control set at skin temp. of 36.5°C. Skin, rectal, ambient temp. RR, HR and wt. loss were monitored and recorded every 30 min. Total IWL was significantly lower (p<.01) in Grp A as compared with Grp B infants (1.76±.24 vs 2.74±.3 g/kg/hr). RR, HR and skin temp. were similar in both groups. Ambient temp. was higher (p< .01) in Grp A, 34.6±.25°C. than in Grp B, 30.6±.26°C.; rectal temp. was lower (p<.01) in Grp A, 36.7±.13°C. than in Grp B, 37.2±.l°C. The lower IWL of Grp A infants may be due to a smaller skin-air ambient temp. gradient in Grp A than in Grp B. The shield may also alter air flow pattern, resulting in an insulating layer of saturated air over the baby which reduces evaporation from the skin.

PREDICTION OF OUTCOME OF MECONIUM ASPIRATION SYNDROME (MAS) BY ROENTGENOGRAMS

Chest x-rays are helpful in confirming the diagnosis of MAS. In this study, x-rays were evaluated as potential prognosticating tools for predicting the outcome. Eighty infants were studied retrospectively. Initial (0-12hrs) x-ray findings were tabulated without knowledge of clinical outcome. Twenty-five infants needed assisted ventilation; 14 died. X-ray findings were associated with: infiltration in 62 infants, hyperinflation 37, air leaks 25, cardiomegaly 17, segmental or lobar consolidation or atelectasis (C/A) 44. Respiratory failure and mortality were significantly higher (p<.001) in infants who had C/A than in those who showed other x-ray findings (23/44vs2/36; 13/44vsl/36). Pneumothorax was also associated with a higher (p<.05) incidence of respiratory failure but was not related to outcome. Although infants who had C/A had similar gestational age and Apgar score compared to those without C/A, they showed significant differences in initial RDS score (5.3+0.3vs3.9+0.3) and blood gases (Mean±S.E.).From this study, it appears that the initial chest film is of value in predicting outcome and that MAS may be divided into two groups; those associated with C/A having a worse prognosis than those without C/A.