Emerging predictors of femoral artery occlusion after pediatric cardiac catheterization

The Objective was to review the prevalence of femoral artery occlusion (FAO) after cardiac catheterization in children up to 12 years old from two centers in China and identify its related risk factors. After collecting clinical data from patients who had undergone pediatric cardiac catheterization, univariate and multivariate analysis were used to evaluate the correlations between FAO and clinical factors, including sex, age, height, weight, sheath size, operation time, therapeutic strategy, sheath/age, sheath/height and sheath/weight. The ROC curve was also used to assess the influence of risk factors to predict FAO. FAO occurred in 19 (0.9%) out of 2,084 children following cardiac catheterization. Patients with younger age, lower height, longer operation time, electrophysiological (EP) diagnosis or/and therapy for arrhythmias, higher Sheath/Age, higher Sheath/Height and higher Sheath/Weight ratios had higher risk for FAO compared to their respective control groups (p < 0.05). In the multivariate analysis, sheath/age and operation time were independent risk factors for FAO. Patients with operation time > 77.5 min or sheath/age > 0.5334 had a significantly higher risk for FAO. Operation time and sheath/age were confirmed as significant and independent risk factors associated with FAO. Operation time > 77.5 min and sheath/age > 0.5334 could effectively predict high risk of FAO after pediatric cardiac catheterization.

Novel Trilaminar Polymeric Antiadhesion Membrane Prevents Postoperative Pericardial Adhesion

BACKGROUND

Postoperative pericardial adhesion formation is a prominent cause of morbidity and death in cardiovascular surgery, but there is still no ideal prevention method, especially in redo cases. This study investigated a novel antiadhesion trilaminar polymeric film compared with the Gore PRECLUDE Pericardial Membrane (W. L. Gore & Associates, Flagstaff, AZ) and a negative control.

METHODS

Our novel trilaminar membrane is composed of polyvinyl alcohol (PVA) and carboxymethylcellulose (CMC). An established pericardial adhesion rabbit model was used to test the property of the membrane. After sternotomy, a portion of pericardium was resected and the epicardium was abraded. Rabbits (n = 24) were randomly assigned to 3 groups: control group, no trilaminar membrane or expanded polytetrafluoroethylene (ePTFE); ePTFE group, or trilaminar membrane group (PVA-CMC group). Evaluation of adhesion formation was performed by resternotomy 4 weeks after the operation.

RESULTS

The degree of tissue adhesion surrounding the heart in the PVA-CMC group was significantly less than in the control (P < .01) and ePTFE (P < .05) groups. The inflammation score in group PVA-CMC was significantly lower than that in the ePTFE (P < .01) and control (P < .01) groups. The fibrosis score was significantly lower in group PVA-CMC than that in the ePTFE (P < .05) and control (P < .01) groups.

CONCLUSIONS

The novel trilaminar membrane effectively reduced postoperative pericardial adhesions. The placement of the trilaminar membrane at the time of sternal closure provides a novel combination to minimize the extent and severity of pericardial adhesions while providing a physical barrier between the sternum and the cardiac structures.

The modified ‘no touch’ technique in the antegrade endovascular approach for left common carotid artery ostial stenosis stenting

Background

Open surgery and the retrograde endovascular approach via the distal left common carotid artery (LCCA) have some limitations in LCCA ostial stenosis treatment. The ‘no touch’ technique used in the renal artery was modified for this situation.

Methods

Fifteen selective LCCA stenosis patients were treated by the modified ‘no touch’ technique in the antegrade endovascular approach from March 2013 to March 2016. Thirteen underwent the transfemoral approach and the other two had the transbrachial approach due to a ‘bovine aortic arch’. Distal embolic protection devices were used in all cases. Follow-up included a neurological examination, carotid duplex scan, and office interview. Mean follow-up time was 18.2±11.5 months.

Results

The initial technical success rate was 100%. The average procedure time was 84.0±16.3 min. There were no procedure-related deaths. No clinical neurological complications occurred during the in-hospital stay. No incidence of death or major stroke occurred during the follow-up period; 6.7% (1/15) of patients had a contralateral minor stroke, 66.7% (4/6) of symptomatic patients were relieved of initial symptoms, and the rest showed improvement. No patient developed new ipsilateral neurological symptoms and no in-stent restenosis occurred during the follow-up period. These results were confirmed by ultrasound.

Conclusions

The modified ‘no touch’ antegrade endovascular technique is a feasible method for treating LCCA ostial lesions with a satisfactory initial success rate, acceptable procedure time, and comparable mid- and long-term results. This technique could be considered as a complementary option for LCCA ostial stenosis in addition to open surgery and the retrograde endovascular approach.

Radionuclide diagnosis of infradiaphragmatic total anomalous pulmonary venous drainage

We hypothesized that infradiaphagmatic total anomalous pulmonary venous drainage (ITAPVD), because of its unique physiology, could be diagnosed with radionuclide angiography. Seven neonates with severe respiratory distress were injected intravenously with 3 mCi technetium-99m pertechnetate. In each of four neonates demonstrated to have ITAPVD by pulmonary angiography, nuclide recirculation through the right atrium occurred 3-6 s after initial passage. In addition, direct visualization of the anomalous common pulmonary trunk with nuclide as a "tail" below the diaphragm was obvious in the third infant studied. This prompted review of the first two infants with ITAPVD; in retrospect the anomalous trunk was also visualized with nuclide in both of these infants. All three were injected via the upper extremity. In the fourth ITAPVD infant, nuclide was injected via the lower extremity. In that infant, preferential streaming of the inferior vena caval flow and nuclide across the foramen ovale into the left heart led to simultaneous opacification of anomalous trunk and descending aorta, obscuring the "tail" sign.

The effect of a neonatal telecardiology system on respiratory therapy in very low birthweight infants

Factors in the U.S. healthcare system have shifted the site of care of many newborns to hospitals where subspecialty services are unavailable. This study examines whether a more rapid turn-around of echocardiogram interpretations and availability of interactive video during neonatal consultations reduces the morbidity of very low birthweight (VLBW) infants. The two groups (n = 21 and n = 28) were similar on the basis of known risk factors. A composite index of respiratory therapy intensivity and duration was used to measure the utilization of respiratory therapies. The index was similar in both groups, 89.6 +/- 12.6 before versus 89.5 +/- 13.0 with telemedicine. These results show little evidence of a reduction in RT utilization.

Effects of long-term infusion of prostacyclin (epoprostenol) on echocardiographic measures of right ventricular structure and function in primary pulmonary hypertension. Primary Pulmonary Hypertension Study Group

BACKGROUND

Right heart failure is an important cause of morbidity and mortality in primary pulmonary hypertension. In a recent prospective, randomized study of severely symptomatic patients, treatment with prostacyclin (epoprostenol) produced improvements in hemodynamics, quality of life, and survival. This article describes the echocardiographic characteristics of participants in this trial; the relationship of echocardiographic variables to hemodynamic parameters, exercise capacity, and quality of life; and the echocardiographic changes associated with prostacyclin therapy.

METHODS AND RESULTS

The 81 patients enrolled in this multicenter trial were randomized to treatment with a long-term infusion of prostacyclin in addition to conventional therapy (n = 41) or conventional therapy alone (n = 40) for 12 weeks. Echocardiograms and assessments of hemodynamics, exercise capacity, and quality of life were performed before and after the treatment phase. On baseline evaluation, patients had marked right ventricular dilatation and dysfunction, abnormal septal curvature, and significant tricuspid regurgitation with a high regurgitant velocity. Pericardial effusions were common. More pronounced abnormalities in right heart structure and function were associated with higher pulmonary arterial and mean right atrial pressures, lower cardiac index, and impaired exercise capacity but had no predictable relationship to quality-of-life indicators. The 12-week infusion of prostacyclin had beneficial effects on right ventricular size, curvature of the interventricular septum, and maximal tricuspid regurgitant jet velocity.

CONCLUSIONS

The echocardiographic manifestations of severe primary pulmonary hypertension reflect abnormalities in hemodynamics and exercise capacity. Prostacyclin has beneficial effects on right heart structure and function that may contribute to the clinical improvement and prolonged survival observed with this drug.

Effect size and experimental power analysis in a paediatric cardiology telemedicine system

A telemedicine system was installed between the University of North Carolina Hospitals and the New Hanover Regional Medical Center. It allowed the transmission of neonatal echocardiograms for immediate reporting. During a six-month study period the system was used for the interpretation of 110 echocardiograms from 48 babies. There were 38 babies studied in a retrospective control period. Hospital length of stay decreased by an average of six days in the telemedicine group, representing an annual saving of some $1.3 million. However, these apparent differences were not significant (P = 0.2) and a power analysis suggested that a sample size of some 600 would have been necessary.

A comparison of continuous intravenous epoprostenol (prostacyclin) with conventional therapy for primary pulmonary hypertension

BACKGROUND

Primary pulmonary hypertension is a progressive disease for which no treatment has been shown in a prospective, randomized trial to improve survival.

METHODS

We conducted a 12-week prospective, randomized, multicenter open trial comparing the effects of the continuous intravenous infusion of epoprostenol (formerly called prostacyclin) plus conventional therapy with those of conventional therapy alone in 81 patients with severe primary pulmonary hypertension (New York Heart Association functional class III or IV).

RESULTS

Exercise capacity was improved in the 41 patients treated with epoprostenol (median distance walked in six minutes, 362 m at 12 weeks vs. 315 m at base line), but it decreased in the 40 patients treated with conventional therapy alone (204 m at 12 weeks vs. 270 m at base line; P < 0.002 for the comparison of the treatment groups). Indexes of the quality of life were improved only in the epoprostenol group (P < 0.01). Hemodynamics improved at 12 weeks in the epoprostenol-treated patients. The changes in mean pulmonary-artery pressure for the epoprostenol and control groups were -8 percent and +3 percent, respectively (difference in mean change, -6.7 mm Hg; 95 percent confidence interval, -10.7 to -2.6 mm Hg; P < 0.002), and the mean changes in pulmonary vascular resistance for the epoprostenol and control groups were -21 percent and +9 percent, respectively (difference in mean change, -4.9 mm Hg/liter/min; 95 percent confidence interval, -7.6 to -2.3 mm Hg/liter/min; P < 0.001). Eight patients died during the study, all of whom had been randomly assigned to conventional therapy (P = 0.003). Serious complications included four episodes of catheter-related sepsis and one thrombotic event.

CONCLUSIONS

As compared with conventional therapy, the continuous intravenous infusion of epoprostenol produced symptomatic and hemodynamic improvement, as well as improved survival in patients with severe primary pulmonary hypertension.

Pre- and postnatal effects of chronic maternal hypoxia on substance-P immunoreactivity in rabbit brainstem regions

The effect of chronic maternal hypoxia on substance-P immunoreactivity (SPI) was examined in brainstem regions of fetal (gestational day E-28), neonatal (postnatal days 3, 7, 14, 21), and adult rabbits. Time-dated pregnant rabbit does were housed in environmental chambers at gestational day E-10. Between E-14 and E-28, the pregnant does were separated into two groups. Group 1, the control group, breathed 21% O2/79% N2 and group 2 the hypoxia-exposed group, breathed 12-14% O2/86-88% N2. Sacrifice occurred at various days depending on the experimental paradigm. On gestational day E-28, 6 pregnant animals were delivered by hysterotomy and the pups were immediately sacrificed. On and after gestational day E-28, the remaining 12 pregnant animals breathed room air. These animals delivered spontaneously between E-30 and E-32 and the pups remained with their mothers until sacrifice. On postnatal days 3, 7, 14, and 21, SPI was measured by radioimmunoassay in the colliculi (fetal animals), superior and inferior colliculi (postnatal analysis), pons and medulla (both groups). In both prenatally normoxia- and hypoxia-exposed animals, SPI was highest in the medulla, intermediate in the pons and lowest in the colliculi. SPI increased with development. Chronic maternal hypoxia did not alter the caudal-rostral profile nor did it alter the maturational increase in SPI. However, chronic maternal hypoxia increased SPI in prenatal animals and decreased SPI in postnatal animals at 14 and 21 days of life but not in postnatal 3- and 7-day-old animals. These data support the concept that regional differences exist in basal SPI within the brainstem of fetal and neonatal animals, and that maternal hypoxia has both immediate and long-term effects on brainstem SPI.

Synthetic surfactant for rescue treatment of respiratory distress syndrome in premature infants weighing from 700 to 1350 grams: impact on hospital resource use and charges

To determine the impact of the use of synthetic surfactant on hospital resource use and charges, we analyzed the economic data from a multicenter, randomized, placebo-controlled clinical trial of synthetic surfactant in infants with neonatal respiratory distress syndrome and birth weights between 700 and 1350 gm. Two 5 ml/kg doses of a synthetic surfactant (Exosurf Neonatal) or air placebo were administered to 419 infants who were receiving mechanical ventilation and had an arterial/alveolar oxygen tension ratio < 0.22. In addition to the clinical endpoints for safety and efficacy, data were collected on length of hospital stay, days in the neonatal intensive care unit, days of mechanical ventilation, days of oxygen supplementation, and hospital charges until the infant reached 1 year adjusted age. Growth and development of infants who received synthetic surfactant therapy in the study and survived to 1 year adjusted age were equivalent to those of the survivors in the air placebo group. For 1-year survivors, synthetic surfactant reduced the average length of stay at the different levels of care needed during the hospitalization such as neonatal intensive care unit days, days of mechanical ventilation, and days of oxygen supplementation. For nonsurvivors, synthetic surfactant increased the average length of stay, especially at more intense levels of care. Total hospital charges for the initial hospitalization and through 1 year adjusted age for a hypothetic cohort of 100 infants treated with synthetic surfactant were, on average, the same as those for a comparable cohort of infants in the air placebo group. These results indicate that rescue therapy with synthetic surfactant in infants with respiratory distress syndrome and birth weights from 700 to 1350 gm can result in significantly improved survival without significant increases in hospital charges.

Effect of different surfactants on pulmonary group B streptococcal infection in premature rabbits

OBJECTIVES

To evaluate the effects of different surfactants on pulmonary infection with group B streptococci in premature rabbits and to examine the effects of different surfactants on pulmonary alveolar macrophage function of newborn rabbits.

MODEL

Preterm and term rabbit pups.

METHODS

Rabbit pups were infected with GBS aerosols followed by intratracheal administration of either calf lung surfactant extract, minced porcine lung surfactant (Curosurf), synthetic surfactant (Exosurf Neonatal), minced bovine lung surfactant (Survanta), human amniotic fluid-derived surfactant, rabbit surfactant, saline vehicle, or no treatment. Intrapulmonary clearance of GBS was determined by comparing bacterial counts in left lungs cultured immediately after aerosol infection with similarly infected lungs analyzed 4 hours after surfactant therapy. Phagocytosis of streptococci was ascertained by microscopic examination of the right lungs fixed in situ at 4 hours. For comparison, an in vitro method was used to measure growth of GBS in the different surfactants.

RESULTS

Preterm animals had a sixfold increase in pulmonary bacterial growth compared with a slight decrease in intrapulmonary GBS in term animals when all were delivered by cesarean section (p < 0.05). In premature rabbits, GBS proliferation was lowest in animals treated with Exosurf Neonatal and highest in animals receiving Curosurf and human amniotic fluid-derived surfactant (p < 0.05). None of the surfactants promoted accelerated growth of GBS in comparison with control animals. Similar growth of GBS was seen in in vitro cultures. Intrapulmonary phagocytosis of GBS in premature pups was not altered by any of the surfactants. In term rabbit pups, the following measures of macrophage population kinetics remained normal at 1 and 24 hours after surfactant administration: viability, cell numbers based on lung lavage, and in vivo incorporation of thymidine.

CONCLUSIONS

Surfactants used in clinical practice do not accelerate the in vivo growth of group B streptococci in the lungs of preterm rabbits. Some surfactants inhibit streptococcal proliferation. The effects of different surfactants are not explained by changes in macrophage function.

Economic outcomes of colfosceril palmitate rescue therapy in infants weighing 1250g or more with respiratory distress syndrome: results from a randomised trial

An analysis of the economic data from a multicentre, randomised, placebo-controlled clinical trial of colfosceril palmitate in infants with neonatal respiratory distress syndrome (NRDS) and birthweights of 1250g or more is presented. Two 5 ml/kg (67.5 mg/kg) doses of a synthetic surfactant (colfosceril palmitate) or air placebo were administered to 1237 infants who were receiving mechanical ventilation and had an arterial/alveolar oxygen tension ratio of less than 0.22. In addition to the clinical end-points for safety and efficacy, data were collected on length of hospital stay, days in the neonatal intensive care unit, days on mechanical ventilation, days on oxygen, and hospital charges until the child reached 1-year adjusted age. One-year adjusted age is attained when the time elapsed since birth is equal to 365 days plus the number of days of prematurity. Rescue treatment with synthetic surfactant therapy has been shown to reduce the incidence of complications of NRDS. Growth and development of infants who received colfosceril palmitate therapy in the study and survived to 1-year adjusted age were equivalent to those of the survivors in the air placebo group. For the cohort of treated infants, colfosceril palmitate reduced the average length of stay at 2 levels of care needed during both the initial hospitalisation (a reduction of 8 days overall and 5 days in intensive care) and all first year hospitalisations (a reduction of 9 days overall and 5 days in intensive care). Total hospital charges for the initial hospitalisation and through 1-year adjusted age for a hypothetical cohort of 100 infants treated with colfosceril palmitate were less than those for a comparable cohort in the air placebo group. The results would, therefore, suggest that rescue therapy with colfosceril palmitate in infants with NRDS and birthweights over 1250g can result in substantial reductions in hospital resource utilisation and charges in addition to the clinical benefits associated with its use.

Survival in primary pulmonary hypertension with long-term continuous intravenous prostacyclin

OBJECTIVE

To evaluate the effects of long-term-intravenous infusion of prostacyclin on exercise capacity, hemodynamics, and survival in patients with primary pulmonary hypertension.

DESIGN

Open, multicenter, uncontrolled trial.

SETTING

Four referral centers.

PATIENTS

18 patients with primary pulmonary hypertension: 1 New York Heart Association (NYHA) class II patient, 13 NYHA class III patients, and 4 NYHA class IV patients.

INTERVENTIONS

Continuous intravenous prostacyclin administered by portable infusion pumps. All patients were treated with anticoagulant agents.

MEASUREMENTS AND MAIN RESULTS

With the 6-minute walk used to evaluate exercise capacity, patients could walk on average more than 100 meters farther after prostacyclin therapy was initiated (distance at 6 months, 370 +/- 119 meters compared with 264 +/- 160 meters at baseline; P < 0.001; distance at 18 months, 408 +/- 138 meters; P = 0.02 compared with baseline). Hemodynamics were improved at 6 months: The cardiac index increased 18% (95% CI, 0.1% to 36.7%; P = 0.02), and mean pulmonary artery pressure and total pulmonary resistance decreased 9% (CI, 1.4% to 15.7%; P = 0.03) and 26% (CI, 6.1% to 46.3%; P = 0.02), respectively, compared with baseline. The improvements in cardiac index and total pulmonary resistance were maintained at 12 months (27% increase [CI, 1.3% to 51.9%; P = 0.05] and 32% decrease [CI, 9.7% to 53.6%; P = 0.02] compared with baseline, respectively). Survival was improved in NYHA class III and IV patients who received continuous prostacyclin (n = 17; follow-up, 37 to 69 months) when compared with historical controls who received standard therapy (National Institutes of Health Primary Pulmonary Hypertension Registry, n = 31, P = 0.045). Kaplan-Meier estimates of 1-, 2-, and 3-year survival rates for the patients treated with prostacyclin were 86.9%, 72.4%, and 63.3%, respectively, compared with 77.4%, 51.6%, and 40.6% for the historical control group (hazard ratio, 2.9 [CI, 1.0 to 8.0; P = 0.045]). Serious complications attributable to the drug and delivery system included two deaths and seven episodes of nonfatal sepsis in three patients.

CONCLUSIONS

Continuous intravenous prostacyclin resulted in sustained clinical and hemodynamic improvement and probably in improved survival in patients with severe primary pulmonary hypertension. Despite potentially serious complications, long-term prostacyclin may be especially helpful in seriously ill patients awaiting transplantation.

Pulmonary mechanics and energetics in preterm infants who had respiratory distress syndrome treated with synthetic surfactant

Pulmonary mechanics and energetics were determined in 32 neonates with respiratory distress syndrome, who were randomly assigned to receive treatment with an exogenous synthetic surfactant, Exosurf Neonatal, or air placebo. Pulmonary mechanics were measured before and 2 hours after surfactant (n = 13) or air placebo (n = 19) treatment, then longitudinally at 24, 48, and 72 hours after treatment, and again at 7, 14, and 28 days of age. There were no significant differences in the values for pulmonary mechanics or energetics 2 hours after the first dose of surfactant. Improvement in pulmonary mechanics was apparent 24 hours after surfactant treatment, when dynamic compliance was 36% greater than in the placebo group (p less than 0.03). Lung compliance values were also higher in surfactant-treated infants 48 and 72 hours after treatment, with a maximal increase of 64% at 7 days of age (p less than 0.03). Surfactant treatment also caused a significant decrease in total pulmonary resistance at 48 and 72 hours after initial treatment and at 14 days of age (p less than 0.04). Similarly, a decrease in flow-resistive work of breathing was demonstrated 24, 48, and 72 hours after surfactant treatment. At 28 days of age, pulmonary mechanics were not different in the two groups. We conclude that beneficial effects of surfactant on pulmonary mechanics were not apparent 2 hours after dosing but were evident 24 hours after dosing and persisted for the first 7 to 14 days of life.

Reduced mortality in small premature infants treated at birth with a single dose of synthetic surfactant

A randomized controlled trial of Exosurf Neonatal, a synthetic exogenous surfactant, was performed. Exosurf was given to premature infants weighing 700-1350 g, by instillation down the endotracheal tube during mechanical ventilation, within 1 h of birth. Control infants were treated with air. Dose administration was performed in secrecy by clinicians who maintained the blind for 2 years. A total of 109 infants received air and 109 received Exosurf; 19 infants with congenital pneumonia or major malformations were excluded from the primary efficacy analysis. By the age of 28 days there were 14 deaths in the air group and 4 deaths in the Exosurf group, a 69% reduction with Exosurf (P = 0.020). Survival without bronchopulmonary dysplasia at the age of 28 days was significantly improved by 15% (P = 0.050). By the age of 1 year post-term there were 19 deaths in the air group and 10 deaths in the Exosurf group, a 42% reduction with Exosurf (P = 0.104). There were no significant changes in the incidence of bronchopulmonary dysplasia, pulmonary air leaks, intraventricular haemorrhage, patent ductus arteriosus, necrotizing enterocolitis or infection. The reduction in mortality indicates important results in high risk premature infants treated soon after birth with a single dose of Exosurf.

Prostaglandins and control of breathing in newborn piglets

To investigate the possible role of prostaglandins in regulation of postnatal breathing, phrenic neural activity (PMO) was recorded as an index of breathing in 42 anesthetized, paralyzed piglets less than 30 days of age (weight 2.4 +/- 0.2 kg, age 9.9 +/- 1.5 days) who were mechanically ventilated with 100% O2 at a fixed tidal volume (8-10 ml/kg). End-tidal CO2 was held constant by an electronic servocontroller which adjusted ventilator rate; ventilator rate was monitored as an index of CO2 production. Rectal temperature was maintained at 39.0 +/- 0.2 degrees C. The effects on PMO of intravenous and brain ventricular injections of NaCl and agents active in the prostaglandin cascade were compared. Intravenous (0.25-1.0 mg/kg, n = 9) and brain (5-33 micrograms/kg, n = 6) indomethacin, a cyclooxygenase inhibitor, doubled PMO within 30 min. Intravenous (1-10 micrograms/kg, n = 6) and brain (1-40 micrograms/kg, n = 6) prostaglandin E1 inhibited PMO by one-half at 10 and 30 min.

Chronic maternal hypoxia. Effect of mid-gestational maternal hypoxia on methionine-enkephalin concentrations within pre- and postnatal rabbit brainstem regions

We examined the effect of chronic maternal hypoxia on methionine-enkephalin concentrations in fetal (gestational day E-28) and neonatal (postnatal days 3, 7, 21) brainstem regions. Pregnant rabbits were housed in environmental chambers at gestational day E-10. Between E-14 and E-28 the pregnant rabbits were separated into two groups. Group I were controls (C) and breathed 21% O2/79% N2 and group II, hypoxia (H), breathed 12-14% O2/86-88% N2. Sacrifice occurred at various days depending on the experimental paridigm. On gestational day E-28, the first group of 6 pregnant animals (3 C, 3 H) were delivered by hysterotomy and the pups were immediately sacrificed. On and after gestational day E-28, the remaining 12 pregnant animals breathed room air. These animals delivered spontaneously between 30 and 32 days of gestation. The pups remained with their mothers until sacrifice. On postnatal days 3, 7, or 21, methionine-enkephalin was measured by radioimmunoassay in the colliculi (fetal animals), superior and inferior colliculi (postnatal animals), pons and medulla (both groups). In both normoxia-exposed and hypoxia-exposed animals, methionine-enkephalin was highest in the medulla, intermediate in the pons, and lowest in the colliculi. Chronic maternal hypoxia significantly increased the methionine-enkephalin concentration in the pons of E-28 fetuses (p less than 0.02). Levels were increased in the medulla as well but these did not reach significance (p = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Prostacyclin and PGE1 treatment of pulmonary hypertension

Prostacyclin and PGE1 show promise in treatment of many forms of pulmonary hypertension. Their clinical use can be expected to increase as their pulmonary vasodilating effects become better known. There is as yet no unequivocal reason to choose one agent over the other, but several observations suggest that prostacyclin will eventually be preferred. First, prostacyclin appears to have a shorter half-life (1 to 2 min), which means that any drug-induced adverse effects will disappear more quickly. Although it is commonly said that up to 80% of PGE1 is metabolized with one passage through the lungs, in one study 34% of intravenously administered radiolabeled PGE1 remained in the bloodstream 20 min after administration. Second, prostacyclin causes less severe and less prolonged rebound platelet activation after discontinuation. Third, prostacyclin has been shown to reduce resting pulmonary vascular tone and hypoxic pulmonary vasoconstriction in virtually every published study in every species tested at every stage of development (fetal, newborn, and adult life); results with PGE1, although very impressive, have been less consistent. Nevertheless, there is little doubt that PGE1 is a powerful pulmonary vasodilator in most clinical situations complicated by pulmonary hypertension. Further, PGE1 is available for clinical use, while prostacyclin remains an investigational drug. Thus, it is likely that PGE1 will become the "nitroprusside" of the lesser circuit for intensive care use, a position PGE1 will hold alone at least until prostacyclin becomes available. Chronic infusions of prostacyclin may prove particularly useful in patients with primary pulmonary hypertension awaiting heart-lung transplantation. Eventually, orally available prostacyclin and PGE1 analogs will offer a new therapeutic avenue in many diseases complicated by chronic pulmonary hypertension.

Radionuclide diagnosis of anomalous origin of the right pulmonary artery from the ascending aorta (so-called hemitruncus)

A 5-week-old infant presented with signs of severe congestive heart failure and pulmonary hypertension. Injection of technetium-99m pertechnetate demonstrated anomalous perfusion of the right lung. Subsequently, anomalous origin of the right pulmonary artery from the ascending aorta was proven at cardiac catheterization and repaired. Repeat injection of radionuclide 1 week postoperatively demonstrated normal flow to the right lung.

Childhood traumatic infarction causing left ventricular aneurysm: diagnosis by two-dimensional echocardiography

After being struck by an automobile, a 9 year old boy developed transient right bundle branch block followed by electrocardiographic changes of inferior wall myocardial infarction and an increase of serum cardiac enzymes. Two-dimensional echocardiography demonstrated a prominent septal aneurysm. Subsequent cardiac catheterization confirmed septal aneurysm and demonstrated an additional inferior aneurysm. Six weeks after the accident, resection of the inferior aneurysm was performed. At 1 year follow-up study, residual septal aneurysm and cardiomegaly are present, but the boy is asymptomatic.

Structural cardiovascular abnormalities presenting as persistent pulmonary hypertension of the newborn

Among the many causes of PPHN may be numbered several cardiovascular malformations. This article introduces the concept of PPHN due to congenital heart disease, illustrates each of the five categories of congenital heart disease that present as PPHN, and outlines noninvasive approaches for diagnosis of congenital heart disease in infants with PPHN.

Clinical manifestations of congenital syphilitic hepatitis: implications for pathogenesis

To study the clinical course and biochemical features of congenital syphilitic hepatitis, the records of all 22 pediatric patients admitted to North Carolina Memorial Hospital between 1969 and 1979 with a positive maternal, cord blood, or serum VDRL were reviewed. Of the seven infants identified with symptomatic congenital syphilis, five had clinical and biochemical evidence of liver dysfunction. All five were jaundiced (peak bilirubin ranged from 8.4 to 29.8 mg/dl, in each case greater than 40% conjugated). Peak transaminase elevation ranged from seven to 150 times normal. Serum glutamic-oxaloacetic transaminase exceeded serum glutamic-pyruvic transaminase in each infant, the difference ranging to 7,400 U. The onset of illness did not occur until after treatment had been initiated in two of these five cases. Liver dysfunction increased with treatment in all four infants with serial enzyme determinations. Liver dysfunction also persisted for more than 6 weeks after adequate treatment in two cases. Liver biopsy 5 weeks after treatment in another infant showed giant cell hepatitis. These observations suggest that treatment can potentiate liver dysfunction in congenital syphilis and that viable treponemes are not necessarily essential in the pathogenesis of the hepatitis.

Neurotransmitters and biphasic respiratory response to hypoxia

Recent work from this laboratory (J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 55:483-488, 1983) has shown that the biphasic respiratory response to hypoxia in piglets is due to changing central neural respiratory output. To test the hypothesis that either adenosine or opiatelike neurotransmitters mediate the failure to sustain hyperpnea in response to hypoxia, 12 piglets were studied at a mean age of 2.9 +/- 0.4 days (range 2-6 days). Animals were anesthetized, paralyzed, and ventilated using a servo-controlled system that maintained end-tidal CO2 constant. Electrical activity of the phrenic nerve was recorded as the index of breathing. An initial experimental trial of 6 min ventilation with 15% O2 was performed in all 12 piglets. Thereafter all 12 piglets were treated with aminophylline (n = 6), naloxone (n = 3), or naltrexone (n = 3) and again subjected to 15% O2. During initial exposure to hypoxia there was an initial increase in phrenic activity that was not sustained. During recovery ventilation with 100% O2, phrenic activity transiently declined below the base-line level and then gradually returned. Subsequent intravenous administration of aminophylline, naloxone, or naltrexone caused base-line phrenic activity to increase. Thereafter repeat exposures to 15% O2 were carried out. During these posttreatment trials of hypoxia, phrenic activity further increased, but the hyperventilation was again not sustained. These findings suggest it is unlikely that either adenosine or mu-endorphin neurotransmitters are the primary mediators of the biphasic response to hypoxia in newborns.

Central neural respiratory response to carotid sinus nerve stimulation in newborns

During exposure to hypoxia newborns hypoventilate following a brief period of hyperventilation. Failure of integration of the afferent signals from peripheral O2 chemoreceptors due to immaturity of the central respiratory centers could explain this paradoxical respiratory response. To test this hypothesis we have utilized anesthetized, paralyzed, mechanically ventilated newborn piglets and lambs (less than 11 days) and old piglets (19-35 days). The vagus nerves were cut in each animal. Respiratory activity was quantified by integration of phrenic neural activity. A carotid sinus nerve (CSN) was isolated and electrically stimulated for periods of 1-6 min. In all three groups of animals respiratory activity was continuously elevated throughout the period of CSN stimulation. After CSN stimulation respiratory activity immediately declined about 25% from the stimulated value. Thereafter respiratory activity declined in an exponential fashion toward the initial control level of respiratory activity. The time constant of this latter decay was 84.2 s in the young piglets, 83.2 s in the old piglets, and 63.0 s in the lambs. These results indicate that the respiratory centers of newborn piglets and lambs can maintain integration of continuous afferent CSN activity. Further, the respiratory afterdischarge that follows CSN stimulus cessation is similar to that of adults. These studies indicate that, during periods of O2 sufficiency, the central respiratory centers of newborns respond in a qualitatively similar manner to CSN stimulation as do adult cats.

Cerebral arteriovenous malformation presenting as persistent fetal circulation. Diagnosis by cross-sectional echo

Two infants with cerebral arteriovenous malformation (CAVM), both initially seen with persistent fetal circulation, were studied with cross-sectional echo. The descending aorta, which is dilated in infants with CAVM, was identified in the subxiphoid four-chamber and short-axis views in both infants. In both infants the arteriovenous malformation was readily identified by cross-sectional echo as a lucency within the brain. Pulsation of the cranial lucency was noted in one infant, but only still frames from the head echo were preserved in the other infant, and pulsation was not commented on in that case.

Infradiaphragmatic total anomalous pulmonary venous drainage: new diagnostic, physiologic, and surgical considerations

Numerous diagnostic pitfalls were noted among 6 infants with infradiaphragmatic total anomalous pulmonary venous drainage, including prolonged moderate respiratory distress in 2 infants, normal cardiac examination in 2, normal electrocardiograms in 2, arterial PO2 in excess of 100 torr in 3 cases, right radial/umbilical arterial PO2 gradients consistent with significant right-to-left ductal shunting in 2 of 4 cases, misleading M-mode echocardiography in 2 of 4 cases, and missed diagnosis at initial cardiac catheterization despite pulmonary angiography in 1 case. Helpful radiographic features included small heart, congested lungs, and pleural effusions in all 6 cases, and visualization of the anomalous trunk overlying the liver on slightly rotated abdominal flat plates in both cases so examined. Bedside umbilical venous catheterization was pathognomonic in 3 cases and suggestive of the diagnosis in the fourth case. Cross-sectional echocardiography was diagnostic in the 1 case in which it was employed. Intraoperative and postoperative pulmonary hypertension led to the demise of the 4 infants who survived long enough to undergo surgery. In addition to early diagnosis, measures to insure maximal decompression of the pulmonary circuit at surgery should improve survival.

Pleural effusion in the first days of life: a prospective study

In a thirty-month prospective study pleural effusions were found on chest radiographs in 33 of 1482 newborns admitted to intensive care units. Congenital heart disease was the most common cause, accounting for eleven cases. Meconium aspiration was the most common respiratory disease associated with neonatal pleural effusion. Infants whose effusions were first noted after the second day of life were likely to have heart disease (p = 0.02). Infants with moderate or large effusions were unlikely to have heart disease (p = 0.04). Prolonged pleural effusion was associated with a prolonged need for supplemental oxygen. Survivors whose effusions lasted three or more days were at increased risk for needing supplemental oxygen for more than twenty-one days (p = 0.07). The overall mortality was 48 percent (sixteen of thirty-three infants died).

Maternal lithium and neonatal Ebstein's anomaly: evaluation with cross-sectional echocardiography

Cross-sectional echocardiography was used to evaluate two neonates whose mothers ingested lithium during pregnancy. In one infant, Ebstein's anomaly of the tricuspid valve was identified. In the other infant cross-sectional echocardiography provided reassurance that the infant did not have Ebstein's anomaly. Cross-sectional echocardiographic screening of newborns exposed to lithium during gestation can provide highly accurate, noninvasive assessment of the presence or absence of lithium-induced cardiac malformations.

Radionuclide diagnosis of cerebrospino-pericardial communication after ventriculoatrial catheter placement for hydrocephalus

A 1-month-old male child with a previously placed ventriculoatrial catheter presented with severe cardiorespiratory distress secondary to cardiac tamponade. A cerebrospino-pericardial communication from right atrial perforation by the catheter was diagnosed quickly and easily by a radionuclide injection of the proximal shunt reservoir.

Interaction of excitatory and inhibitory respiratory afterdischarge mechanisms in piglets

Afferent inputs to the central neuronal networks responsible for respiratory control can have effects on respiratory output that persist even after cessation of the original stimulus. In adults, carotid sinus nerve (CSN) stimulation activates a central excitatory mechanism which causes prolonged elevation of respiratory output. In newborns, superior laryngeal nerve (SLN) stimulation activates a central inhibitory mechanism which causes prolonged inhibition of respiratory output. The present study was designed to confirm that CSN stimulation in newborns also activates a long-acting central excitatory mechanism and to determine in what way the long-acting excitatory and inhibitory mechanisms interact. Anesthetized, paralyzed, and vagotomized piglets (2-30 days) were studied. Integrated phrenic nerve activity was determined before, during, and after stimulus trials consisting of CSN and SLN stimulation alone or following trials of sequential or simultaneous CSN and SLN stimulation. Respiratory output following CSN stimulation remained elevated and only gradually declined to the base-line value. Respiratory output following SLN stimulation remained depressed and only gradually recovered to the base-line value. One minute after cessation of the sequential trials, the respiratory output was intermediate between that of CSN or SLN stimulation alone at equivalent poststimulus times. We conclude that the central neural mechanisms which mediate the persistent poststimulus effects of CSN and SLN stimulation are independent but that they interact for a prolonged period following simultaneous or sequential activation. In infants, this interaction may effect respiratory stability during episodes of central or obstructive apnea and hypoxia.

Central origin of biphasic breathing pattern during hypoxia in newborns

The ventilatory response to moderate hypoxia of both animal and human newborns differs significantly from that of adults. The newborn response is characterized by transient hyperpnea followed by return of ventilation toward or below the control level and even apnea. To determine whether central respiratory control mechanisms are affected by hypoxia in newborns, we used an anesthetized, paralyzed, mechanically ventilated piglet model in which the vagus nerves were cut. Respiratory activity was determined by measuring electrical activity of a cut phrenic nerve. During a 6-min continuous exposure to 15% O2 as the inspired gas, 11 piglets increased their respiratory output to 181 +/- 38% of the control value within 2.5 min. However, by the 6th min the average respiratory output had declined to 104 +/- 25% of the control. During the exposure to hypoxia, the servo-controlled ventilator frequency (an index of CO2 flux to the lungs) was persistently greater than control (28.0 +/- 1.0 vs. 30.5 +/- 1.4 cycles/min; P less than 0.01). These data indicate that the newborn's characteristic breathing response to hypoxia is due to failure of central neural respiratory control mechanisms. Paralysis, constant end-tidal PCO2, and increased ventilator rate during hypoxia exclude changes in pulmonary mechanics or decreased metabolic rate as explanations of the paradoxical decline in respiratory output.

Developmental aspects of the effect of naloxone on control of breathing in piglets

The respiratory effects of a stereospecific opiate antagonist, naloxone, were studied in two groups of paralyzed and vagotomized piglets who were servoventilated on 100% oxygen. Phrenic neural activity was used as the index of respiratory output. In 7 piglets less than 10 days of age naloxone infusion caused phrenic minute output to increase 122 +/- 36% (P less than 0.01). This change was accounted for by a significant increase only in peak phrenic activity, the neural equivalent of tidal volume. Frequency did not change significantly. In 7 piglets 20-34 days of age naloxone infusion caused phrenic minute output to increase 54 +/- 12% (P less than 0.025). Both peak phrenic activity and frequency were significantly increased. The increase in respiratory output observed in the younger piglets was significantly greater than that of the older piglets (P less than 0.05). These findings indicate that endogenous endorphins have a significant, though changing, role in control of breathing in the developing piglet.