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Objective To study the differences in blood pressure readings between the auscultatory and oscillometric (Dinamap model 8100; Critikon, Tampa, Fla) methods. Design Survey of 2 blood pressure instruments. Setting Public schools. Participants Seven thousand two hundred eight schoolchildren aged 5 through 17 years. Main Outcome Measure Blood pressure levels. Results For all children combined , Dinamap systolic pressure readings were 10 mm Hg higher (95% confidence interval, −4 to 24 mm Hg) than the auscultatory systolic pressure readings. Dinamap diastolic pressure readings were 5 mm Hg higher (95% confidence interval, −14 to 23 mm Hg) than the auscultatory Korotkoff phase V diastolic pressure readings. Conclusion These findings preclude the interchange of readings by the 2 methods. Caution must be exercised in the diagnosis of hypertension when an automated device is used.

Acquired hemidiaphragmatic paralysis from phrenic nerve injury has been described in a variety of traumatic and surgical conditions, including birth trauma, neoplasms, and complications of thoracic surgery1and jugular venous cannulation.2,3We observed the case of an 8-year-old child in whom a temporary paralysis of the left hemidiaphragm developed from an empyema, with eventual resolution in 16 months. To our knowledge, empyema has not been reported as a cause for paralysis of the ipsilateral hemidiaphragm. Report of a Case.An 8-year-old boy presented to the emergency department with a traumatic puncture wound, 2 cm in length, to the left subscapular region after falling on a tree root earlier that evening. The initial evaluation revealed no foreign body in the chest wall, and the chest roentgenogram was without abnormalities. The patient's wound was treated by primary closure in the emergency department, without surgical exploration. The child returned to the

Relative sensitivities tp ouabain of atrial and ventricular muscles from 1-week and 4-month rabbits were compared in vitro. Ventricular muscles were also studied with prior treatment that minimized unphysiological, stimulation-induced release of norepinephrine (propanolol and/or reserpinization). Atrial and pretreated ventricular muscles from the newborn showed (a) higher sensitivity to ouabain and (b) the same "relative' positive inotropic effect (RPIE) when compared to those of the adult (RPIE is ouabain-induced inotropism relative to the maximal calcium-induced inotropism and represents ouabain-specific-inotropism). With no prior treatment, ventricular muscles from the newborn showed a nonsignificant tendency toward a lower sensitivity to ouabain and a significantly lower RPIE than those of the adult. These results suggest that under normal physiological conditions, the newborn myocardium may be more sensitive to ouabain than that of the adult.

Age-related changes in the response rabbit papillary muscles to isoproterenol and calcium were studied. Newborn rabbit papillary muscles were not only less sensitive to the inotropic effect of isoproterenol and calcium, but also produced significantly less maximal inotropic tension to these agents in comparison to the adult. The decreased response of newborn papillary to isoproterenol appears to be due to a combination of (a) decreased ability of papillary muscle to respond to calcium and (b) immaturity of isoproterenol-sensitive contractile mechanism. Differences in myocardial norepinephrine content do not appear to play an important role in the age-related difference in the response to isoproterenol and calcium.

Effects of prostaglandins (PGs) E1, E2, F2 alpha and I2 in a wide range of concentration were examined in mesenteric and cerebral arteries isolated from mature baboons. PGs E1, E2 and F2 alpha at low concentrations (10(-10) to 10(-7) M) elicited relaxation in helically cut strips of cerebral arteries precontracted with phenylephrine. In contrast, the PGs did not cause relaxation in the mesenteric artery. PGI2 (10(-9) to 10(-6) M) produced marked relaxation in both arteries. The EC25 for PGI2 in the mesenteric artery was significantly lower than that in the cerebral artery. During baseline conditions, cerebral arteries contracted in response to high concentrations (greater than 10(-7) M) of PGs E1, E2 and F2 alpha. In mesenteric arteries, a large contraction was induced by PGs F2 alpha and E2 but not by PGE1. Arachidonic acid (10(-6) M) produced an aspirin-inhibitable relaxation in both arteries to a similar extent, so that the vasodilator PG(s) formed in the two different arterial walls appear to exert a similar relaxant action. Thus, the baboon mesenteric artery was more sensitive to PGI2 for the relaxant effect than was the cerebral artery, while PGs F2 alpha, E1 and E2 caused only a contraction in the mesenteric artery but both relaxation and contraction in the cerebral artery.

The myocardium of the neonate has incomplete sympathetic innervation and decreased sensitivity to cardiotonic agents. It is not known whether the neonatal myocardium exhibits the tendency to develop reserpine-induced supersensitivity to cardiotonic agents. Using isolated ventricular muscles from 1-week-old and adult rabbits, concentration-response relationships of inotropic tension to isoproterenol, ouabain, norepinephrine and calcium were determined with and without reserpine pretreatment. Ventricular muscles from the newborn animals exhibited the same degree of reserpine-induced supersensitivity to isoproterenol and ouabain as that seen in the adult animals. Although the newborn demonstrated reserpine-induced supersensitivity to calcium, the adult did not. Neither age group demonstrated reserpine-induced supersensitivity to norepinephrine. These findings indicate that newborn animals are capable of producing reserpine-induced supersensitivity, despite the immaturity of their cardiac sympathetic innervation, contractile machinery and beta-adrenergic mechanisms. These results also indicate the non-selective nature of reserpine-induced supersensitivity.

Effects of varying temperature (26, 32, 38 degrees C) on age-related differences in inotropic and chronotropic sensitivities were investigated on electrically stimulated left atria and spontaneously beating right atria isolated from newborn and adult rabbits. Adult tissue had significantly greater sensitivity (low ED50) than newborn tissues to isoproterenol-induced inotropic responses at 26 and 32 degrees C (p less than 0.01), but not at 38 degrees C. The chronotropic sensitivity of adult tissues was significantly greater than the newborn at 26 degrees C (p less than 0.01), but not different at 32 or 38 degrees C. It is concluded that age-related differences in inotropic and chronotropic responses in vitro are more pronounced at low temperatures and tend to disappear at physiological temperatures.

Indirect BP measurement was obtained in the right upper arm in 219 healthy newborn infants with the Dinamap monitor and was compared with values obtained from the calf to establish normative BP values and to help establish a diagnosis of hypertension and coarctation of the aorta in the newborn. There were 174 Mexican-Americans (79.5%), 33 whites (15.0%), and 12 blacks (5.5%). The width of the BP cuff was selected to be 0.4 to 0.5 times the circumference of the extremities. Three supine position readings of BPs and heart rate were obtained from each site and were averaged for statistical analyses. Mean arm BP values (±SD) of the neonate less than 36 hours of age were 62.6±6.9/38.9± 5.7 mm Hg (48.0±6.2 mm Hg). Neonates older than 36 hours had slightly but significantly (P

To find whether effects of adrenergic and cholinergic agents on cerebral artery were dependent on maturity, we examined responses of isolated cerebral artery strips harvested from premature, term newborn and adult baboons. Although cerebral arteries from many species are only mildly sensitive to norepinephrine, we found the perinatal cerebral arteries to be quite responsive to the amine. Cerebral arteries from premature and newborn baboons were significantly (P less than 0.001) more sensitive to norepinephrine than were arteries from adults; medium effective concentration (EC50) for norepinephrine were 3 X 10(-8), 6 X 10(-8) and 32 X 10(-8)M for prematures, newborns and adults, respectively. Arteries showed a similar age-dependence in the sensitivity of the response to phenylephrine, an alpha 1-adrenoceptor agonist. EC50 values for KC1 did not differ among groups, nor did the maximum response to norepinephrine. Arteries from premature and newborn baboons showed marked contractile response to acetylcholine (maximum tensions 5.9 +/- 0.6 and 6.4 +/- 0.8 g/mm2, respectively), whereas arteries from adult baboons showed little response (0.6 +/- 0.1 g/mm2). Arteries from premature and newborn animals showed a more marked relaxation response to isoproterenol than did arteries from adult animals; the degree of relaxation from an induced contraction was 63% (premature), 72% (newborn) and 10% (adult). There was no age-dependence in the relaxation response to sodium nitrite. We conclude that the events coupling alpha 1, beta or muscarinic receptor activation with cerebral arterial contraction or relaxation are more effective in perinatal than in adult baboons.

It has been shown that the sensitivity to isoproterenol of myocardial inotropic response increases with growth in rabbits. In the present study we attempted to delineate the biochemical mechanisms involved in this maturation-related change. We investigated cyclic AMP generation and protein kinase activation by isoproterenol in the ventricular myocardium of rabbits aged 1 day, 1 week, and 1 month. In contrast to an increase in inotropic response, both the sensitivity to isoproterenol of cyclic AMP generation and the sensitivity to exogenous cyclic AMP of protein kinase activation decreased with maturation from 1 day to 1 month of age. ED50 of isoproterenol (mean +/- SE) on cyclic AMP generation in myocardial slices was 1.83 +/- 0.42 x 10(-7) M for 1-day-old, 3.70 +/- 0.61 x 10(-7) M for 1-week-old, and 8.32 +/- 1.20 x 10(-7) M for 1-month-old rabbits. Likewise, the ED50 of isoproterenol on adenylate cyclase activation was 0.65 +/- 0.11 x 10(-7) M, 2.04 +/- 0.32 x 10(-7), and 15.2 +/- 2.5 x 10(-7) M in 1-day, 1-week- and 1-month-old rabbits, respectively. The ED50 of cyclic AMP on protein kinase activation was 1.50 +/- 0.64 x 10(-8) M for 1-day-old and 7.08 +/- 1.52 x 10(-8) M for 1-month-old rabbits. This apparent discrepancy between inotropic response and biochemical response in the sensitivity to isoproterenol indicates that the biochemical mechanism of the maturation-related change in inotropic response was at a step or steps distal to protein kinase activation.

Accurate blood pressure determination is crucial in the management of critically ill infants and children, in detecting secondary hypertension amenable to surgical correction, and in the early detection of essential hypertension. However, the pediatric literature consists of contradictory methodology and extreme variations in the «limits of normal». An indirect blood pressure measuring device requires validation against a direct arterial pressure

An echocardiographic technique (V scan) for confirming the diagnosis of double-outlet right ventricle is described. The technique demonstrates a frequent pathologic feature of double-outlet right ventricle, ie, origin in both great arteries side by side and anterior to the ventricular septum. The V scan offers greater diagnostic accuracy than the mere demonstration of mitral-semilunar valvular discontinuity.

Sphygmomanometric indirect blood pressure readings on the arm were compared to direct blood pressure readings from the radial and pedal arteries in pediatric patients. The direct systolic pressure in the pedal arteries was significantly (p less than 0.001) greater (25.1 +/- 12.3 mm Hg) than the indirect arm systolic pressure. The direct systolic pressure from the radial artery was identical to the indirect systolic arm pressure. Although there were no statistical differences between direct and indirect diastolic pressures, correlations for diastolic pressures were relatively poor. These data indicate that (1) there is a significant and unpredictable amplification of systolic pressure in the pedal arteries which may result in erroneous diagnosis of hypertension or jeopardize early detection of circulatory shock, (2) indirect blood pressure measurement with the recommended cuff width (125% of arm diameter or 40% of arm circumference) accurately reflects direct systolic pressure in the radial artery, and (3) indirect blood pressure measurement gives a relatively poor prediction of direct diastolic pressures.

A new entity of right aortic arch with isolation of the left innominate artery is described in a three-day-old boy with complete endocardial cushion defect. Embryologically, this type of anomaly will result if the interruption of the embryonic left aortic arch occurs at two sites, one between the left ductus arteriosus and the descending aorta and the other between the ascending aorta and the left common carotid artery. Absence of pulse in the left arm and on the left side of the neck strongly suggests this anomaly. The aortogram and pulmonary arteriogram may confirm the diagnosis of this anomaly during life.

Congenital levojuxtaposition of the right atrial appendage is a rare malformation most commonly associated with a transposition of the great arteries. We report a case of levojuxtaposition of the right atrial appendage associated with a persistent truncus arteriosus, type 4. Juxtaposition of the atrial appendage is a sign of severe cyanotic congenital heart disease, and this is best diagnosed by a selective right atriogram or superior venacavogram.

A successful two-stage surgical repair of tetralogy of Fallot with absent pulmonary valve is reported. A newborn with hyperinflated lungs and tachypnea underwent pulmonary artery banding and an aortopulmonary artery shunt, which reversed the air trapping. A successful corrective operation was performed at 28 months of age, and the patient remains asymptomatic at 44 months of age. We believe that infants with signs of tracheobronchial compression should undergo pulmonary artery banding, with or without a Blalock-Taussig shunt, to relieve airway compression by the pulsatile, aneurysmal pulmonary arteries. Corrective operation can be delayed.

SummaryThe purpose of this study was to determine whether acute hypoxia in vitro or chronic hypobaria alter the response of pulmonary artery smooth muscle to vasoactive substances proposed as mediators of hypoxic pulmonary vasoconstriction. Dose response curves to PGF2α, A-II, EPI, NE, and 5-HT were obtained on helical strips of pulmonary artery and thoracic aorta from normal and chronically hypobaric (one-half atmosphere for 2 weeks) rats, under the conditions of high and low oxygen tension in the tissue bath. Chronic hypobaria increased the reactivity of pulmonary artery to PGF2α and decreased it to A-II when compared to normal rats. Acute hypoxia did not change the reactivity of pulmonary artery to any of the agents tested. Similar changes were not observed in aorta.

In dog mesenteric arteries, nialamide (10(-5) M), a monoamine oxidase inhibitor, potentiated contractile response to tyramine but not to noradrenaline or transmural electrical stimulation (TES). Bretylium, desipramine or prior reserpinization inhibited the potentiating action of nialamide on the tyramine-induced contraction. Contractions induced by octopamine were not reduced by prior reserpinization. In the coronary artery, relaxing responses to tyramine were potentiated but those to noradrenaline and TES were not potentiated by nialamide. In the cerebral artery, nialamide failed to potentiate tyramine-induced contraction. The functional role of intraneuronal monoamine oxidase in sympathomimetic effects is discussed.

Prostaglandin E2 (PGE2) and its antagonists were tested for their effects on the chronotropic responses induced by electrical stimulation of autonomic nerve fibers in the isolated, spontaneously beating, rabbit sino-atrial node. PGE2 (8 × 10−7M) almost completely blocked positive chronotropic responses induced by stimulation of intrandal sympathetic fibers at low frequencies (2 – 5 Hz), while it had no effect at high frequencies of stimulation (20 – 100 Hz). Negative chronotropic responses induced by stimulation of intranodal parasympathetic fibers were only slightly and insignificantly reduced by PGE2 at low frequencies (2 – 20 Hz), and were increased at high frequencies (50 – 100 Hz). Three prostaglandin antagonists, polyphloretin phosphate (PPP), 7-oxa-13-prostynoic acid (EC-I-148) and 1-acetyl-2-(8-chloro-10,11-dihydrodibenz(b,f)(1,4)oxazepine-10-carbonyl) hydrazine (SC-19220), failed to antagonize the inhibitory effects of PGE2 on the chronotropic response induced by stimulation of intranodal fibers in the isolated sino-atrial node.

Cooling of isolated guinea pig tracheal smooth muscle from 38 to 28 degrees C over 2.25 min produced a transient contraction followed by sustained relaxation. The cooling-induced contraction was blocked either by pretreatment with ouabain at concentrations of 10(-5) M or greater or by substitution of normal physiological salt solution with K-free solution. In contrast, the contractile response to cooling was not inhibited by pretreatment with phentolamine (10(-5) M), atropine (10(-5) M), tetrodotoxin (3 X 10(-7) M), diphenhydramine (10(-5) M), cromolyn sodium (10(-3) M), indomethacin (3 X 10(-7) M), nifedipine (10(-7) M), or verapamil (3 X 10(-6) M). Addition of NaHCO3 to the bath during cooling, preventing a change in pH of the physiological salt solution, did not affect the cooling-induced contraction. It is concluded that cooling of isolated guinea pig trachea produces a transient ouabain-sensitive contraction, and that the data suggest the contraction is mediated by inhibition of Na-K-ATPase in the smooth muscle rather than through neuronal stimulation or chemical mediator release.

Summary The foregoing discussion leads to several general conclusions regarding the use of digoxin in the pediatric patient. First, pharmacokinetic studies indicate that somewhat higher doses are required in the infant to attain the same serum levels as in the adult. Important sources for this difference appear to be more rapid body clearance of digoxin and larger volume of distribution in the infant. Second, higher serum digoxin levels are not indicated on the basis of decreased myocardial uptake of digoxin in the infant. Tissue uptake of digoxin, as indicated by myocardium/serum digoxin ratios, is higher in infants and children than in adults. Third, according to results of animal studies, the inotropic sensitivity to digoxin in the young is probably greater—certainly not less—than in the adult. This is opposite to a commonly held view that the immature heart is less sensitive to cardiac glycosides and therefore requires higher serum levels for a therapeutic effect. Rather, the infant has decreased sensitivity of the conduction system to digitalis toxicity, and healthy myocardium less prone to arrhythmia than the adult. Therefore the infant may tolerate, but does not require, higher serum levels of digoxin. Fourth, high levels of serum digoxin (>2 ng/ml) are not associated with greater inotropic effects in the pediatric patient. The higher dosages of digoxin are, instead, associated with greater frequency of toxic effects, especially in infants receiving concomittent diuretic therapy. Therefore, a digoxin dosage recommendation is presented, that will result in mean serum digoxin levels of 1.1 to 1.7 ng/ml. Fifth, the classic ECG signs of digoxin toxicity derive from reactions in adult hearts with coronary artery disease and do not apply to immature or healthy cardiac tissue. In the pediatric patient a common first sign of digoxin toxicity is a prolongation of the PR interval, whereas in most adults it is an increased frequency of arrhythmias. Cautious practice would include digoxin doses aimed at moderate serum levels (1.0 to 2.0 ng/ml), ECG monitoring, especially during digitalization, and avoidance of hypokalemia. Clinical status and presence or absence of ECG signs of toxicity are as good guides to dosage as are frequent serum level determinations in infants older than 2 months. In newborn or premature infants, who have immature digoxin elimination mechanisms, frequent serum level determinations are necessary.

1. 1. Maturation-related changes in alpha- and beta-adrenergic mechanisms of the aorta were investigated in 1 day, 1 week, 1 month and 4 month old rabbits and guinea-pigs. 2. 2. Aortic strips from newborn rabbits were equally as sensitive to phenylephrine as strips from the older rabbits. 3. 3. Aortic strips from newborn rabbits did not relax as well in response to isoproterenol as did the strips from adult rabbits, although relaxation to sodium nitrite was comparable in both groups. 4. 4. Aortic strips from 4 month old guinea-pigs had less sensitivity to phenylephrine than did the three younger age groups. 5. 5. Relaxing ability of newborn guinea-pig aorta to isoproterenol and sodium nitrite was equal to that of adult guinea-pig aorta.

Helically cut strips of thoracic aorta and main pulmonary artery from rabbits of varying age were examined for their ability to relax with cumulative doses of isoproterenol (ISO) and sodium nitrite (NaNO2) in the presence of appropriate blocker(s) in isolated tissue baths. The baths contained Kreb's solution maintained at 37°C and oxygenated with 95% O2  5% CO2. The vessels were preconstricted with 3 × 10−6M 5-hydroxytryptamine (5HT) which produced approximately 95–100% of maximal contraction to the drug. The relaxation induced by ISO or NaNO2 was expressed as a percent of contraction produced by this dose of 5HT. The magnitudes of percent relaxation produced by 1 × 10−3M NaNO2 were the same for all age groups, but those produced by ISO were significantly less in the 1–2 day and 7–10 day groups than in the 1 month and 4–5 month groups in both the aorta and pulmonary artery (p < 0.01). These findings indicate that the beta-adrenergic receptor function in the aorta and pulmonary artery of the newborn rabbit is not fully developed but it matures with age.

Blood flow was measured with a mercury-in-rubber straingauge plethysmograph in the utilized and intact extrem­ ity during and 24 hours after uncomplicated (with no clinical signs of vascular insufficiency) percutaneous right and left cardiac catheterization in 20 children. In this group, there was a significant decrease of the flow in the utilized extremity after entry into the artery, with the flow returning to normal within 24 hours after the pro­ cedure. Flow was markedly reduced in the utilized ex­ tremity of a child who developed thrombosis of the femoral artery after catheterization. Seven additional children were studied one to four years after retrograde catheterization. In this group the flows in utilized and intact extremities were equal at rest and with reactive hyperemia. It is concluded that uncomplicated transfemoral percutaneous cardiac catheterization in children does not impair the blood flow in the limbs. r F , he percutaneous technique has become increasA ingly popular as a means of cardiac catheter­ ization in children and even in infants since it was introduced by Seldinger 1 in 1953.2 To our knowl­ edge, the effects of this technique on blood flow in the limbs during and after catheterization in chil­ dren have not been reported. Recently, Vyden et al3 reported the effects of transfemoral catheteriza­ tion on blood flow to the lower extremity in 20 adult patients using pneumoplethysmographic studies and concluded that arterial catheterization causes a significant decrease of blood flow in the catheterized extremity lasting at least 24 hours. The purpose of our study was to determine whether percutaneous arterial catheterization in children causes significant changes in blood flow in the limbs during and immediately after catheter­ ization and on a long-term basis. Plethysmographic measurements of blood flow in both utilized and intact extremities during and after transfemoral percutaneous right and left cardiac catheterization were obtained in 20 children. In an additional seven children, studies of flow were done one to four years after retrograde catheterization. MATERIALS AND METHODS

• To establish whether there is a difference between infants and adults in the relationship of serum levels of digoxin to dosage or the ratio of myocardial to serum digoxin levels, the concentrations of digoxin in right atrial appendage (RAA) and serum were measured in 12 infants and 17 adults undergoing open heart surgery. Although the daily digoxin dose per weight for the infants was significantly greater than that for adults, there was no difference in the serum digoxin levels for the two groups. We found, however, a considerable difference in myocardial digoxin levels. The RAA digoxin levels were 211.8 ± 72.1 ng/g of wet weight in infants and 35.1 ± 7.7 ng/g of wet weight in adults. Similarly, the RAA-serum digoxin ratio was much higher in infants (149 ± 30) than in adults (28 ± 5). These data indicate discrepancies between infants and adults in the pharmacokinetics of digoxin, especially with respect to myocardial uptake. ( Am J Dis Child 1982;136:418-420)

We compared laser-Doppler velocimetry with plethysmographically determined changes in skin blood flow (SkBF) in five studies on four men. Increments in SkBF were induced by raising whole-body skin temperature to 39 degrees C for 50–70 min. We found laser-Doppler blood flow (LDF) to correlate well with total forearm blood flow (FBF) within each study (r = 0.94–0.98), but the relationship varied among studies. Thus the slopes for the LDF vs. FBF relationship varied from 40 to 122 mV X ml-1 X 100 ml X min. The value for LDF at zero FBF, extrapolated from the regression relationships, ranged from 246 to 599 mV above the value for LDF set with the probe on a stationary object. The value for LDF when blood flow to the arm was mechanically occluded ranged from 110 to 230 mV. In a second series, we measured the LDF values from six sites on forearms of each of four normothermic men. There was marked regional variation, with 1.8- to 5.7-fold ranges in LDF within a given subject. Values for LDF during occlusion of the forearm were more consistent within and between subjects. Thus LDF appears to provide a good indicator of the response pattern of SkBF from the region of illuminated skin. However, variability in the relationship to total SkBF (probably arising from variation in the number of perfused capillaries in the small volume of tissue) and uncertainties in the value of LDF at zero SkBF make quantitative use difficult.

1. Maturation-related changes in the response of atrial myocardium to beta-adrenergic stimulation were investigated in 1-day, 1-week, 1-month and 4-month old rabbits and guinea pigs. 2. A trial myocardium of 1-day and 1-week old rabbits were significantly less sensitive to isoproterenol than the two older groups. No such relationship was found with atrial myocardium of the guinea pig. 3. Isoproterenol-sensitive inotropic effect was also maturation-related in rabbit atrial myocardium, being significantly less in the 1 day and 1 week groups than the two older groups, while no such relationship was found in the guinea pig.

• We measured blood pressure (BP) and heart rate in 1554 healthy infants and children aged 2 weeks to 5 years using an oscillometric device, to establish normative values in this age group. The BP cuff width was selected to be 40% to 50% of the circumference of the upper arm. Triplicate measurements of BP and heart rate were obtained in the waiting room of pediatricians' offices and well-baby clinics before the patients were examined by the physician or nurse. Three readings were possible in 87% of the infants less than 3 years of age and in all children 3 years of age and older. The average BP value (systolic/diastolic [mean]) increased rapidly from the 2- to 3-week value of 78/47(59) mm Hg to the 1- to 5-month value of 95/60(74) mm Hg. No subsequent increase in BP occurred until 2 years of age (96/56 [71] mm Hg) when systolic and mean pressures started to increase at an average annual rate of 2 mm Hg for systolic pressure and 1 mm Hg for mean pressure until reaching the 5-year value of 104/58 (75) mm Hg. Diastolic pressure did not increase from 1 month to 5 years of age. Heart rate decreased with increasing age from the 2- to 3-week value of 153 to the 5-year value of 97 beats per minute. There was no difference in BP and heart rate values between boys and girls or among ethnic groups over the age ranges studied. Considering the high success rate in obtaining BPs in infants and small children, it appears that BP should be determined routinely, regardless of the age of the patients, when an oscillometric device is available. ( AJDC . 1989;143:860-864)

Cumulative responses to prostaglandins E1 (PGE1), E2 (PGE2), F1α(PGF1α), and F2α (PGF2α) were obtained on isolated human umbilical arteries and veins. All four prostaglandins produced contractions. PGF2α was the most active prostaglandin on umbilical arteries, while PGE2 and PGF2α were equiactive and more potent than PGE1 or PGF1α on umbilical veins. 5-Hydroxytryptamine (5-HT) was at least 100 times more potent than the prostaglandins. SC-19220, a prostaglandin antagonist, in a high concentration was found to moderately antagonize the vasoactive effect of PGE2 and to slightly antagonize contractions to 5-HT. Also, propylene glycol, the solvent for SC-19220, was observed to antagonize contractions to both PGE2 and 5-HT, thereby indicating that solvent controls are necessary when evaluating compounds such as SC-19220.

Intra-arterial pressure in the brachial artery was compared with that in the femoral artery in children. There were no significant differences in systolic, diastolic, or mean pressures. The average auscultatory systolic pressure in the arm, obtained with a cuff 20% wider than the limb, was identical to the average direct systolic pressure in the brachial and femoral arteries. The auscultatory systolic pressure in the leg, using the same criterion for cuff width, was 11 mm Hg higher than the direct pressures. The discrepancy could represent (1) a systematic error in cuff size of inadequate width or length or (2) additional systolic amplification between the femoral and popliteal arteries. Since the femoral pressure is widely used in cardiac catheterization, this pressure is suggested as the standard for calibrating auscultatory technics. For leg blood pressure measurements a cuff at least 25% wider than the average leg diameter and long enough to encircle the limb is recommended.

We report a case of cor triatriatum in a 4-year-old girl on whom precise anatomic diagnosis was made preoperatively by cardiac catheterization and angiocardiography. The anomalous septum was removed through successful surgery. The condition had been diagnosed two years earlier as pulmonary hypertension secondary to a ventricular septal defect, in spite of a high pulmonary artery wedge pressure (PAWP). We emphasize the importance of the PAWP in separating pulmonary venous hypertension from other forms of pulmonary hypertension since this subgroup is usually operable and even curable if surgery is performed before irreversible pulmonary vascular changes occur. In spite of the small risk, we feel that angiocardiographic studies are necessary to demonstrate the anomalous septum.

To the Editor.— Recently the National Heart, Lung, and Blood Institute Task Force on Blood Pressure Control in Children published revised normal BP standards and guidelines for children.1 I welcome this effort, as reliable normative data have been unavailable but are prerequisite for the early detection of hypertension and its proper treatment. The guidelines published by the Task Force for the detection of hypertension, the diagnostic evaluation, follow-up laboratory testing, and treatment are, in my opinion, excellent.

Prostaglandin (PG) E1 is used in neonates with certain cyanotic congenital heart defects to maintain patency of the ductus arteriosus, but its effects on cerebral blood flow are not well known. Vasodilator response (expressed as % of 10−4M papaverine-induced relaxation) and vasoconstrictor response (as % of 30 mM KC1-induced contraction) to PGs were examined in helical strips of cerebral arteries isolated from premature (0.75 gestation), full term newborn and adult baboons. PGs I2, E1, E2 and F2α at low concentrations of 10−10 to 10−8M produced a vasodilation in the arteries from all age groups. Maximum vasodilator responses to PGI2 were similar between adult and newborn arteries (95-100%). Vasodilator response to PGE1 was much greater in newborn than adult arteries; adult arteries relaxed to 20±9% (N=8) at 10−9M PGE1 and contracted above the baseline at 10−8M, whereas newborn arteries relaxed to 53±7% at 10−9M and 74±8% at 10−8M (N=7). Similarly greater relaxation was found in newborn than adult arteries with PGE2 and PGF2α. No significant difference was found between premature and newborn arteries in relaxation response to all 4 PGs. PGs E1, E2 and F2α at concentrations of 10−8M or greater produced a marked contraction in adult arteries, but small or no contractions in premature and newborn arteries. The results indicate that the cerebral arteries of premature and newborn baboons are more responsive to vasodilator actions, but less responsive to vasoconstrictor actions of PGs than adult arteries.

We report a case of recurrence of the ventricular shunt as a result of bacterial endocarditis more than seven years after the surgical correction of tetralogy of Fallot (TOF) that was treated successfully with an intravenous antimicrobial alone. Report of a Case .—This 13-year-old boy had corrective surgery for TOF at the age of 6. The ventricular septal defect (VSD) was closed with a Teflon patch and the right ventricular outflow tract was resected. A widely split second heart sound and a grade 2/6 pulmonary ejection murmur were present. A regurgitant murmur of a VSD was not described on five clinic visits postoperatively. Complete right bundle branch block was present on the ECG and roentgenograms demonstrated a normal heart size and vascularity. The patient was admitted to a local hospital with history of fever and shaking chills of ten days' duration. Five consecutive blood cultures were positive for Staphylococcus aureus

Responses of cerebral arteries to certain vasoactive agents are known to be different from those of extracerebral arteries. We compared vasoconstrictor response to norepinephrine (NE) and vasodilator response to isoproterenol (ISO) between strips of baboon cerebral (CAs) and mesenteric (MAs) arteries and among premature (0.75 gestation), full term newborn and adult baboons for each artery.

Myocardial response to beta-adrenergic stimulation, isoproterenol(ISO), was evaluated in 1 day, 1 week, 1 month and 4 months old rabbits by measuring maximal developed tension(MDT), ED50 and cyclic AMP(cAMP) production. Isolated electrically stimulated (2/sec) atrial strips were studied. The ratio of MDT to ISO and CaCl2(Ca) increased progressively with age: 45.3 ± 2.7%, 61.1 ± 2.6%, 70.1 ± 2.3%, and 89.1 ± 1.5% (p < 0.05). This ISO/Ca ratio normalizes the data for the increase in muscle mass with age. ED50 values for Ca were the same for the 4 age groups. ED50 for ISO progressively decreased from 1 day to 1 month of age: 74.3 ± 13.1, 31.9 ± 9.2, 5.5 ± 0.8, × 10−9M (p < 0.05), but there was no difference between 1 month and 4 months old (5.6 ± 0.8, × 10−9M) groups. These findings indicate that newborn myocardium has a decreased sensitivity to ISO and a relatively less MDT to ISO as well. The mechanism of this decreased responsiveness to ISO was evaluated by measuring cAMP production in response to ISO. Myocardial slices were incubated for 5 min in Krebs-Ringer's buffer with/without 10−6M ISO. In contrast to the decreased tension response shown above there was a greater increase in cAMP production in newborn than adult myocardium: Δ10.0 ± 0.08, Δ5.3 ± 0.09, Δ1.2 ± 0.2, and Δ1.7 ± 0.3 pmol/mg tissue (p < 0.05). These findings suggest that the difference in responsiveness to ISO of newborn and adult myocardium is in the step(s) distal to cAMP production and proximal to Ca-contractile element interaction.

Sir .—A recent article in the October 1987 issue of AJDC by Wareham et al 1 demonstrated wide 95% prediction intervals (17 to 21 mm Hg) for systolic, diastolic, and mean blood pressures (BPs) as recorded by an oscillometric BP monitoring system (Dinamap 1846) in premature newborns and advised cautious interpretation of the Dinamap BP readings in this age group. It is an interesting finding in the presence of a number of articles confirming the accuracy of Dinamap BP measurements in full-term neonates (references 2 through 7) 1 and in infants and children aged 1 month through 16 years. 2 In fact, we have found the Dinamap method to be a better predictor of intra-arterial BP than the conventional auscultatory readings obtained by research nurses. 2 However, on close inspection of our data, we find a trend of diminished accuracy of the Dinamap readings when arterial pressures were in the