ABSTRACT. Chronic hypoxemia is associated with a decreased growth rate and a decreased rate of cell division. In lambs with experimental cyanotic heart disease, the gain in body mass was decreased. In this study, we determined to what extent the lower body mass in these lambs was related to alterations in body fluid compartment volumes, specifically whether intracellular volume was decreased. Therefore, fluid compartment volumes were studied in nine lambs, after 3 to 4 wk of experimental cyanotic heart disease, and in 13 control lambs. Hypoxemic lambs had a lower arterial oxygen saturation (65 + 11 versus 91 2 2%, p < 0.001) and a higher Hb concentration (142 + 16 versus 101 + 8 g.L-', p < 0.001). The lower body mass in hypoxemic lambs (10.5 + 2.3 versus 13.0 + 2.8 kg) could be mainly accounted for by a decrease in intracellular water volume (4.7 + 1.3 versus 6.6 + 1.5 L, p < 0.01). Total body water (753 + 27 versus 780 + 40 mL.kg-') and extracellular water volume (307 + 25 versus 277 f 15 mL.kg-') in hypoxemic lambs were not significantly different from those in control lambs, but intracellular water volume was decreased (445 + 27 versus 501 + 35 mL.kg-', p < 0.01). The ratio of extracellular to intracellular water volume was higher in hypoxemic lambs (0.69 + 0.10 versus 0.55 2 0.04, p < 0.01). Blood volume was increased in hypoxemic lambs (121 + 29 versus 79 + 15 m L kg-', p < 0.01), mainly due to an increased total red cell volume (48 + 12 versus 22 + 8 mL. kg-',p < 0.001). We conclude that the lower body mass in hypoxemic lambs is mainly related to a lower intracellular water volume. These results and the increased ratio of extracellular to intracellular water volume can be explained by assuming a decreased growth of the intracellular compartment. In addition, a part of the (decreased) growth in hypoxemic lambs must be expended on increased erythropoiesis. (Pediatr Res 33: 267-272, 1993) Abbreviations V,,, extracellular water volume Vi,, intracellular water volume D20, deuteriumoxide i.m., intramuscularly Congenital heart disease is often associated with a decreased growth rate, characterized by a decreased gain in body mass and length (1-3). It seems to affect children with cyanotic heart disease more than children with noncyanotic heart disease (1-3). In young experimental animals exposed to various forms of chronic hypoxemia, a decreased body mass is a common finding (4-8). Based on studies in rats and mice, it has been suggested that a decreased rate of cell division is responsible for the growth retardation (4, 5).The volumes of body fluid compartments change during growth. Both V,, and V,, increase, but per-unit body mass total water and V,, decrease and Vi, increases (9, 10). This can in part be explained by a relatively faster growth of the intracellular compartment (9, 11). In chronic hypoxemia, therefore, body fluid compartment volumes may be altered by the effects of decreased growth.Another factor that may affect fluid compartment volumes is the effect of chronic hypoxemia on blood volume. Blood ...

Neonates are known to regulate CO by changlng HR.Little i s known on changes of stroke volume in slck 1nfants.We measured CO.SV.HR and mean arterlal blood pressure (BP) by Dopplersonography In 40 slck Infants before(A.8) and after (AT, BT) therapy.(A):low CO due to resplratory problems(n=16).(B): hlgh CO due to PDA(n=25). (C) and (D): Normal lnfants(n=40) matched for GA(control).in (A) SV was low and not compensated by a high HR. BP was normal.The rlse of CO after treatment(A1) was due to a rise In SV.In (8) SV was hlgh and normalized after ductus closure (BT), BP was low and 1ncreased.HR dld not change. Conclusion: Neonates with low CO and low preload do not compensate low SV by increasing the HR. Preterm infants can Increase their SV above normal levels if preload is high and afterload is low. CO Cardiac output ( C O ) i n 1 2 i n f a n t s of d i a b e t i c mothers ( I DMs)and i n 20 normal neonates (control group) was estimated evalua t i n g blood velocity i n ascending a o r t a , using a gatedpulsedDopp1 -ervelocimeter with a 5MHz transducer positionated i n the suprasternal nocth. C O (mL/min/Kg)was calculated from the equation: CO=SV. HR, where SV=stroke volume (mL/Kg) and HR = h e a r t r a t e (bpm). Ventricular s e p t a l hypertrophy (IVDS>0.35cm) was found i n 5 of 12 IDMs, but i n none control group. In the group with IVDS >0.35cm, C O and SV were reduced a t comparable HR. Reduced C O i n IOMs with hypertrophic cardiomyopathy was r e l a t e d t o lower SV, due t o decreased l e f t ventricular compliance and limited pre-load. IDMs IDMs IVOS > 0 . 3 5 1 1~~~ < 0.35 P HEMODYNAMIC EFFECTS OF SUBMAXIMAL TREADMILL EXERCISE124 INLAMeswwANmRTop-YsHm(s).JWC Gratama, M Dalinghaus, JJ Meuzelaar, JH Kcers, AM Gerding, M Moncha, JRG Kuipers. Depts of P e d i a t r i c Cardiology and Tkoracic surgery, University Hospital, Groningen, Netherlands. W e showed t h a t S lambs a t r e s t could maintain t h e i r systemic blccd flow (SBF) a t t h e expense of a n increased h e a r t r a t e (HR). Therefore we wondered whether a diminished reserve i n H R would l i m i t t h e S lamts t o perform strenuous exercise. We s t u d i e d 6 7-week-old l a n h ( 1 2 t l kg; mean2SD) with a Goretex @ g r a f t between a o r t a (ao) and pulmonary a r t e r y (pa) (PBF: SBF r a t i o =3).Six lambs without g r a f t served as controls (C). Variables were recorded a t t h e end of a 10 min treadmill run a t 75% of predetermined VO2= h r r i n g exercise HR increased more i n C (108223 t o 239t31 bpm) than i n S lamts (169t32 t o 238t32). Total l e f t v e n t r i c u l a r s t r o k e volume (SVIV) d i d not change i n both groups (5: 2.020. 3 t o 2. 0t0. 3; C: 1. 120. 3 t o 1. 1t0. 1 ml/kg), but t h e f r a c t i o n of t o t a l q, through t h e shunt decreased p e r h e a r t beat s o t h a t t h e f r a c t i o n contributing t o SBF ( e f f e c t i v e SVlv) increased s i g n i f i c a n t l y (5: 0. 720. 2 t o 0. 920. 3). This enabled S l a m b t o increase SBF (118220 t o 216t40 ml/min/kg) t o such an e x t e n t t...

The influence of echocardiography on the n m h r of cardiaccatheterizations(CC) performed prior to cardiac surgery was assessed in a retrospective analysis canparing two 12 month periods(Jan. The extent to which body fluid volumes change as a consequence of chronic hypoxemia is not exactly known. Therefore we measured extracellular and plasma volumes in 5 chronically hypoxemic lambs. Before the 10th day of life we placed an inflatable balloon around the pulmonary artery, performed an atrial septostomy and inserted catheters.0n days 3-4 after surgery the balloonwas gradually inflated. In another 7 lambs only catheters were placed. At 5 weeks of age the lambs were studied. We used single injections of ferrocyanide and Evans blue to measure extracellular and plasma volumes, respectively.-The hypoxemic lambs had a lower aortic oxygen saturation (69+9 (SD) vs 92+2%, p<0.01), and a higher hemoglobin concentration (142t17 vs-97210 9.1-1, p<0.001) and hematocrit (4325 vs 29+6%, p<0.01). Total extracellular fluid volume (320231 vs 27357 mlkg-1, pc0.01) and blood volume (134~33 vs 80212 ml.kg-1, p<0.05) were increased in hypoxemic lambs. This was also true for plasma volume (81+22 vs 58+5 ml.kg-1) and interstitial fluid volume (238+29 vs-215218 mi.kg-I), although these differences did not reach statistical significance.These results show that total extracellular fluid volume and blood volume are both increased in hypoxic lambs, and that total hemoglobin mass is even more increased than the hemoglobin concentration would lead us to expect. This study examines the relationship of A N P to right and left atrial pressures, intracardiac shunts and compares patients with congenital heart disease (N = 11) to a group of normal children (N = 34). During cardiac cath, right and left atrial ANP levels, lntracardlac pressures, and cardiac output were measured and shunt and direction of the shunt were calculated. All ANP results (RIA technique) are in pg/ml (mean2 SD). Of the 11 children, 4 had no intracardiac shunting, 5 had left to right shunts and 2 had right to left shunts. Right and left atrial ANP levels were significantly (p (.005) elevated when compared to the normal control (6.5 + 4 . 9 ) . Right atrial ANP (103.9~98.0) was not different from left zrial ANP (101.6+95.4). T H E R O L E OF ATRIALSeven children with elevated right atrial pressures (RAP2 9 mm Hg) had higher A N P levels than 5 children without elevated RAP (154.9~ 106.5 vs. 42.6238.0, p< .03). .In patients without shunts (N = 4) R A P and ANP levels were highly correlated (R = 0.930). Left atrial A N P levels were also highly correlated with R A P (R = 0.945). Children with intracardiac shunts had poor correlation between A N P and atrial pressures but significantly (p <.05) higher A N P in the right atrium (166.42 111.5, N = 5) than patients without shunt (40.9 + 24.6, N = 4 ) . CONCLIJSION: These unique data indicate that ANT in children is: (1) primarily produced in the right atrium and is correlated with RAP, (2) elevated in congenital heart disease, and (3) ...

F.R.G. Neonates are known to regulate CO by changlng HR.Little i s known on changes of stroke volume in slck 1nfants.We measured CO.SV.HR and mean arterlal blood pressure (BP) by Dopplersonography In 40 slck Infants before(A.8) and after (AT, BT) therapy.(A):low CO due to resplratory problems(n=16).(B): hlgh CO due to PDA(n=25). (C) and (D): Normal lnfants(n=40) matched for GA(control).in (A) SV was low and not compensated by a high HR. BP