There is a narrow difference between the therapeutic and toxic ranges of cardiac glycosides. The availability in the past decade of radioimmunoassays for accurate measurement of these glycosides has resulted in an improved understanding of their pharmacokinetics and clinical use. Despite these advances, however, digitalis toxicity is still a common problem in infants and children.

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Increased levels of urinary β₂-microglobulin (β₂M) have been used as a marker of proximal tubular dysfunction in human neonates. To assess the value of β₂M in the detection of early stages of tubular damage caused by gentamicin, renal handling of β₂M was studied sequentially in 18 gentamicin-treated neonates with idiopathic respiratory distress syndrome (mean birth weight 1,781 g, mean gestational age 33.7 weeks) during the first 7 days of life. These data were compared with those obtained from 10 control infants matched for gestational and postnatal ages. In addition, follow-up studies of renal function were conducted in 14 of 18 study infants 1 week after termination of therapy, on day 14 postpartum. The ( ± SD) fractional tubular excretion of β₂M (FEβ₂M) tended to decrease significantly in the control infants from 10.3 ± 1% on day 1 to 6.5 ± 0.8% on day 7 postpartum (p < 0.05). In infants treated with gentamicin, the mean FEβ₂M rose from 10.5 ± 2% on day 1 to 17.1 ± 1%on day 7 (p < 0.01), followed by a decrease to 8.2 ± 0.5% over the next 7 days (p < 0.001). Compared with the control infants, values for the infants receiving gentamicin were significantly higher on postpartum days 3,5, and 7 (p < 0.001). No significant differences in serum creatinine, creatinine clearance, or fractional tubular excretion of sodium were observed between the two groups during the study period. These results suggest that administration of gentamicin with a penicillin antibiotic to preterm infants with idiopathic respiratory distress syndrome is associated with increased FEβ₂M and that the FEβ₂M may serve as a useful indicator of tubular dysfunction in infants treated with gentamicin.

Continuous monitoring of v i t a l s i g n s , e . g . temperature, blood pressure, heart and r e s p i r a t i o n r a t e s , and E C G , f o r the care of c r i t i c a l l y s i c k infants has become an established hospital routine. W e have compared various non-invasive and invasive continuous Pa02 monitors with a r t e r i a l blood Pa02 levels and find t h a t there i s a considerable c o r r e l a t i o n between the values obtained by d i f f e r e n t procedures. Continuous monitoring procedures permit b e t t e r evaluation of the p a t i e n t than skin c o l o r , ECG monitoring o r c l i n i c a l observation.I t s immediate a v a i l a b i l i t y a t bedside and the capacity t o detect i r r e g u l a r i t y in oxygen supply i s of major c l i n i c a l advantage. These devices help in preventing t h e e f f e c t s of hyperoxemia and hypoxemia. S t a b i l i z a t i o n of s i c k infants can be achieved rapidly without repeated a r t e r i a l blood sampling f o r Pa02 determinations. The r e s u l t s suggest t h a t these continuous Pa02 monitors (invasive o r non-invasive) may be a b l e t o eliminate or minimize conditions l i k e bronchopulmonary dysplasia, r e t r o l e n t a l f i b r o p l a s i a and brain damage due t o lack of oxygen during neonatal development. INTRAUTERINE FETAL RESUSCITATION WITH TERBUTALINENer esh A. Te a n i , Uma L. Verma, S amali Chatter ee.1451 Spo:. by P l a t i n J. Collipp. NassavlCty Med C t r , i l t h S c i C t r , SUNY a t Stony Brook, Dept. of Ob/Gyn, East Meadow, NY Cases of i n t r a p a r t a l f e t a l d i s t r e s s from any cause s u s t a i n f u r t h e r hypoxia during u t e r i n e contractions due t o t h e concomit a n t reduction i n u t e r i n e blood flow during u t e r i n e a c t i v i t y . Therapeutic reduction of u t e r i n e a c t i v i t y should, t h e r e f o r e , res u l t i n recovery of f e t a l h e a r t r a t e (FHR) and f e t a l a c i d o s i s , and t h e b i r t h of a neonate i n a b e t t e r s t a t e of owgenation and acid-base balance. Towards t h i s , t e r b u t a l i n e 250 Ug subcutaneously was i n j e c t e d i n p a t i e n t s with evidence of f e t a l d i s t r e s s . A l l 1 1 p a t i e n t s showed ominous FHR changes. I n 2 of t h e s e , f e t a l s c a l p blood pH (FSB-pH) was not t e c h n i c a l l y possible. I n 2 , t h e FSB-pH was b 7.25. The remaining 7 p a t i e n t s showed FSB-pH 4 7.25.Results: Where adequate FHR t r a c e was a v a i l a b l e , 9/10 pat i e n t s showed marked reduction t o cessation of u t e r i n e a c t i v i t y , and complete o r p a r t i a l recovery of ominous FHR changes. FSB-pH was compared t o t h e mid-point of t h e umbilical vein and a r t e r y pH's. I n t h e 2 cases where t h e o r i g i n a l FSB-pH was b 7.25, no change was seen. However, i n cases with FSB-pH 5 7.25, a s i gn i f i c a n t improvement from a mean of 7.180 + .038 t o 7.270 2 .066 (P = 4 .005) was seen. No major s i d e e f f e d s were noted. ST of AP l i p . e x t . meas...

To determine the effect of dialysate osmolarity on peritoneal dialysis drug transfer, peritoneal dialysis clearances of theophylline, phenobarbital, and tobramycin were determined in 10 rabbits using dialysate containing 1.5 and 4.25% glucose. Urea and creatinine clearances were also obtained for comparison. Under similar dialysis conditions, the peritoneal clearances of the three drugs remained unchanged for the two types of dialysate. In contrast, the peritoneal clearances of urea and creatinine were significantly higher with the use of 4.25 % glucose dialysate (p < 0.001). Thus, peritoneal dialysis clearances of theophylline, phenobarbital and tobramycin are not significantly affected by hypertonicity-induced ultrafiltration during acute peritioneal dialysis.