Methemoglobin formation in children with congenital heart disease treated with inhaled nitric oxide after cardiac surgery

OBJECTIVE

Inhaled nitric oxide (NO) is used as a therapy of pulmonary hypertension in children after cardiac surgery. Hemoglobin binds to NO with great affinity and forms methemoglobin by oxidation in the erythrocyte. Once produced, methemoglobin is unable to transport and unload oxygen in the tissues. The amount of available hemoglobin in the body for oxygen transport is thereby reduced. Anemia, acidosis, respiratory compromise and cardiac disease may render patients more susceptible than expected for a given methemoglobin level. The goal of the present study was to review the cumulative effect of inhaled NO on methemoglobin formation in critically ill children. We therefore looked for methemoglobin levels in children with congenital heart disease after cardiac surgery who were treated with inhaled NO in a range of 5-40 ppm.

METHODS

We retrospectively reviewed the medical charts of 38 children with congenital heart disease after cardiac surgery. We extracted demographic data and physiological measurements at the following time points: (1) T0 = before starting inhaled NO therapy, (2) T1 = 24 h after the beginning of inhaled NO therapy, (3) T2 = half-time therapy, (4) T3 = end of therapy, (5) T4 = 24 h after finishing inhaled NO therapy.

RESULTS

The median duration of inhaled NO therapy was 5.5 days (interquartile range 6, range 2-29), NO concentrations at T1 and T2 were 16 ppm (10, 5-40) and 12.5 ppm (12.3, 2-40), respectively. The median cumulative dose of inhaled NO was 1699 ppm (2313, 193-7018). Methemoglobin levels increased moderately, but significantly, during therapy ( T0 vs T1 p<0.05 and T0 vs T2 p<0.001). The highest methemoglobin level measured was 3.9%. Methemoglobin levels correlated positively with the inhaled NO doses applied at T1 ( r(2)=0.8376; p<0.01) and at T2 ( r(2)=0.8945; p<0.01). At T1 the methemoglobin level correlated negatively with the T1 blood pH value. The overall mortality rate was 13.2% (5 of 38 study patients died). There was no significant difference in methemoglobin levels between survivors and non-survivors.

CONCLUSION

We conclude from our data that the use of inhaled NO therapy for children with congenital heart disease after cardiac surgery in the described range of 5-40 ppm, resulting in a maximum of 4% methemoglobin blood level, is feasible and safe. However, we recommend the use of the minimal effective dose of inhaled NO and continuous monitoring of methemoglobin levels, especially in cases of anemia or sepsis in critically ill children.

Left atrial appendage emptying velocity does not predict postoperative atrial fibrillation in patients undergoing cardiopulmonary bypass

BACKGROUND

Atrial fibrillation is a common complication of cardio-pulmonary bypass and improved pre-operative risk assessment could help guide prophylactic therapy. This study examined whether reduced left atrial appendage flow velocities measured by transoesophageal echocardiography pre-operatively in patients in sinus rhythm predicted development of postoperative atrial fibrillation.

METHODS AND RESULTS

All patients who underwent transoesophageal echocardiography for clinical indications with measurements of left atrial appendage velocities within twelve months prior to cardio-pulmonary bypass were retrospectively identified. Postoperative records were reviewed and the patients divided into two groups based on the presence or absence of clinically significant atrial fibrillation during hospitalization following cardio-pulmonary bypass. Thirty-six patients (mean age 61.1 +/- 14.8 years, 18M/18F) were included in the study. The overall incidence of atrial fibrillation in the cohort was 17/36 patients (47%). Mean left atrial appendage emptying velocity was 50.8 +/- 23.3 cm/s2 (range 26-119) in the patients with sinus rhythm only and 41.5 +/- 16.7 cm/s2 (range 16-76), in the patients with postoperative atrial fibrillation (P=ns).

CONCLUSIONS

In our patient population there was no significant difference in left atrial appendage emptying velocity measured by transoesophageal echocardiography in patients with and without postoperative atrial fibrillation. Pre-operative measurement of left atrial appendage emptying velocity cannot be relied upon to risk stratify patients prior to cardio-pulmonary bypass.

Surfactant therapy in infants and children: three years experience in a pediatric intensive care unit

Despite the established success of surfactant application in neonates, the use of surfactant in older children is still a matter of discussion. We hypothesized that surfactant application in children with acute respiratory distress syndrome (ARDS) secondary to a pulmonary or systemic disease or after cardiac surgery improves pulmonary function. We also asked whether repeated treatment could further improve pulmonary function. To answer these questions, we measured oxygenation index (OI) and hypoxemia score after the first and after a second application of surfactant (50-100 mg/kg body wt) at least 24 h later. We enrolled 19 children (older than 4 weeks) for a retrospective chart review study, and six of them underwent cardiac surgery. Demographic data were extracted. OI and hypoxemia score were estimated before and 2 and 24 h after surfactant application. Lung injury score was calculated before and 24 h after surfactant application. Outcome measures included survival, duration of mechanical ventilation, and pediatric ICU and hospital stay. The median patient age was 9.0 (quarter percentile 3.7/25) months. The median weight was 8.4 (4.1/11.5) kg. The median lung injury score before the first surfactant application was 2.3 (2.3/2.6). Hospital duration and pediatric ICU stay for all patients was 31.0 (20.0/49.5) days and 27.0 (15.5/32.5) days, respectively. The duration of mechanical ventilation was 24.0 (18.5/31.0) days. The overall mortality was 53%. Twenty-four hours after the first surfactant application, pulmonary function significantly improved. The median OI was 14 (5.5/26) before and 7 (4.5/14.5) 24 h after surfactant application (P= 0.027). The hypoxemia score was 91.7 (69.9/154.2) before and 148.4 (99.2/167.6) 24 h after surfactant application (P = 0.0026). Seven children received a second application, which did not further improve pulmonary function. The lung injury score was not influenced by either surfactant application. We conclude that a single surfactant application improves pulmonary function in children with ARDS. A second application of surfactant showed no further benefit. Outcome was not affected in our study population.

Monocyte phagocytosis as a reliable parameter for predicting early-onset sepsis in very low birthweight infants

BACKGROUND

Septic complications lead to a high mortality rate in very low birthweight infants (VLBWI). Therefore, prognostic markers for the development of sepsis attach importance to start an efficient therapy as early as possible.

AIMS

Functional and phenotypical variables of blood monocytes in the cord and peripheral blood were investigated to evaluate the parameters for predicting early-onset and late-onset sepsis (nosocomial infections).

STUDY DESIGN

In a prospective study, 25 VLBWI were investigated.

METHODS

In the cord blood taken immediately after birth, the capacity of the monocytes to phagocytose non-opsonized E. coli bacteria by flow cytometry and the ex-vivo production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta and IL-6 (enzyme-linked immunoassay (ELISA)) after lipopolysaccharide (LPS) stimulation were measured. At the third day, the HLA-DR expression on the monocytes (flow cytometry) and the LPS-induced cytokine production were measured from the peripheral blood.

RESULTS

Five VLBWI already developed early septic complications after 24-72 h, while the other three infants had late-onset sepsis 10-18 days after birth. The prognostic significance for early-onset sepsis was highest for the decreased monocyte phagocytic capacity (sensitivity and specificity: 100%) and for the LPS-induced formation of TNF-alpha and IL-1 beta in cord blood. Moreover, in septic VLBWI, the HLA-DR expression on the monocytes was lowered on day 3 after birth. The prognostic significance for late-onset sepsis was highest for TNF-alpha and IL-1 beta levels in the peripheral blood on the third day after birth.

CONCLUSIONS

The determination of phagocytosis in the cord blood seems to be a reliable parameter for predicting early-onset sepsis and offers the possibility for a forward start of an antibiotic therapy.

Treatment of toxoplasmosis in pregnancy: concentrations of spiramycin and neospiramycin in maternal serum and amniotic fluid

Toxoplasma infection during pregnancy is widely treated with oral spiramycin to reduce the risk of congenital toxoplasmosis in the infant. Failures of therapy have been observed, however. In this study, a sensitive high-performance liquid chromatography technique was used to measure concentrations of spiramycin and neospiramycin, one of the major metabolites of spiramycin, in maternal serum and amniotic fluid. Samples were obtained from 18 women who underwent amniocentesis for polymerase chain reaction (PCR) diagnosis of fetal infection 5-109 days following the prescription of spiramycin therapy (3 g/day). Concentrations of spiramycin and neospiramycin in both serum and amniotic fluid were highly variable, ranging from nondetectable values to 1 microg/ml. None of the concentrations measured were within the range reported to inhibit growth of the parasite in vitro. Consistent with previous reports, part of the observed variability in maternal and fetal drug concentrations could be explained by individual differences in several pharmacokinetic parameters: intestinal absorption, tissue distribution, cellular uptake, metabolism, transfer across the placenta, drug accumulation in fetal tissue, and maternal and fetal drug elimination. The heterogeneity of the data could also be related to differences in patient compliance with the medication prescribed. By addressing factors that could impair adequate treatment of toxoplasmosis during pregnancy, the data presented call for a larger-scale controlled study to determine individual and diurnal variations in maternal drug levels, patient compliance, and outcomes of the offspring. The activity of neospiramycin against Toxoplasma gondii should be assessed.

Neonatal and pediatric extracorporeal membrane oxygenation using nonocclusive blood pumps: the Vienna experience

Neonatal and pediatric extracorporeal membrane oxygenation (ECMO) is carried out commonly using occlusive blood pumps. Centrifugal pumps provide simple and safe technology for transportation on ECMO. The assistence respiratoire extra corporelle (AREC) system enables single needle venovenous ECMO for infants. We report on our experience with neonatal and pediatric ECMO treatments using nonocclusive blood pumps. One-hundred forty-six ECMO treatments were performed for cardiac, neonatal, and pediatric indications in 54, 19, and 27% of cases. Centrifugal pumps were used in 99, and the AREC system in 42 cases. Hospital mortality was estimated retrospectively and influence of type of pump, type of ECMO belonging to indication group, and lactate at ECMO installation were estimated. Irreversible organ failure leading to ECMO termination was investigated within groups of indications. Survival (recent 50 ECMO treatments) was 80, 70, 43, and 30% after meconium aspiration syndrome, acute respiratory distress syndrome, cardiac surgery, and prolonged resuscitation. Lactate exceeding 100 mg/dl at ECMO installation predicted significantly worse outcome. Cerebral damage was the main reason for ECMO termination in all but persistent circulatory failure in the cardiac group. Myocardial recovery resulted in all except 2 cardiac cases. Nonocclusive blood pumps can be used safely in neonatal and pediatric ECMO. Early installation may improve outcome markedly. In cardiac cases results of surgery should be thoroughly investigated on the table before ECMO installation to prevent hopeless ECMO treatments.

[Opiate addiction in gravidity - consequences for the newborn. Results of an interdisciplinary treatment concept]

AIMS

To evaluate the outcome of infants of drug dependent mothers (IDM) after establishing an interdisciplinary attention concept at the University Hospital in Vienna. To compare the influence of different maintenance agents on neonatal morbidity.

PATIENTS AND METHODS

All newborns of opiate dependent mothers were prospectively included from III 1995 to IX 1999. The following data were collected: maintenance agent (methadone, slow release morphine, buprenorphine), infectious status, demographic data, congenital malformations, perinatal complications, as well as incidence and duration of the neonatal abstinence syndrome (NAS). Medical treatment with phenobarbital (1995 - 96) or morphine hydrochloride (MoHCl) (1997 - 99), respectively, was indicated when Finnegan score exceeded 10.

RESULTS

88 neonates (38 females/50 males) with a median gestational age of 39 weeks were included, 18 (20.5 %) were born prematurely. The median birthweight was 2905 g, 24 (27.3 %) infants were small for date (< 10th percentile), 15 (17 %) microcephalic. The malformation incidence was 7.4 %. 63 (72 %) of all newborns had to be treated due to abstinence syndrome: in the methadone group 76 %, in the morphine group 93 %, but in the buprenorphine group 19 % only (p < 0.01). Median duration of withdrawal was 15.1 days (d) with significant difference after antenatal buprenorphine exposure compared to methadone and morphine exposure (8.3 d versus 15 d and 16.5 d respectively). In neonates treated with phenobarbital duration of NAS was 17.6 d, whereas NAS in infants with MoHCl therapy lasted 12.8 d (p < 0.05).

CONCLUSION

Incidence and duration of NAS after buprenorphine exposure was significantly lower than after methadone and morphine exposure. Withdrawal time under morphin-hydrochloride therapy was reduced by one third compared to treatment with phenobarbital.

Position dependent changes of cerebral blood flow velocities in premature infants

The supine or prone positioning of infants has been a cause of much controversy. Recently it has been postulated that the position dependent hypoperfusion of the brainstem represents a possible cause of sudden infant death. To demonstrate position dependency and maturational changes of cerebral perfusion in premature newborn infants we investigated cerebral blood flow velocities (CBFV) in the main supratentorial and brainstem cerebral arteries. Measurements of CBFV were done with transfontanellar colour-coded Doppler sonography in the internal carotid artery (ICA), basilar artery (BA), and vertebral artery (VA) in the prone (head centered-baseline) and supine positions (maximal rotation to both sides) in 23 premature infants aged between 3-5 days of life. We performed follow-up measurements in 17 infants 7-10 days later and in 16 infants at the corrected age of 1 month. There was no difference in mean CBFVs between the prone and supine position at the first investigation. At the third investigation, CBFVs were significantly higher in the supine compared to the prone position. The CBFVs of the ICA were higher than in the BA and VA. This difference was not influenced by the body position but increased with post-natal age more in the VA (159%) than in the BA (129%) and ICA (128%). Position dependency was not seen in the ICA perfusion. In the prone position, five infants showed an incomplete steal effect in the contralateral VA. There was no significant side difference in the CBFVs of the ICA and VA, but in the resistance indices in the VA (left > right).

CONCLUSION

in premature newborns, position dependent changes of cerebral blood flow velocity develop with maturation and are most pronounced in the vertebrobasilar system. These changes are possibly due to compression of the vertebral artery by neck movement and suggest an individual risk of brainstem perfusion deficits that may be aggravated with age and head rotation in a prone position.

Evaluation of the Cerebral Function Monitor as a tool for neurophysiological surveillance in neonatal intensive care patients

BACKGROUND

Cerebral function in critically ill infants is difficult to assess and would certainly require continuous monitoring. Therefore, this study was performed to evaluate the Cerebral Function Monitor (CFM) as a tool for continuous neurophysiological surveillance in the Neonatal Intensive Care Unit (NICU).

PATIENTS

A total of 40 neurological risk neonates were included in the study. They were classified on the basis of their primary diagnoses as infants with clinically manifest seizures, suspected seizure activity, intracranial hemorrhage (ICH) and hypoxic-ischemic encephalopathy (HIE). A group of 20 neurologically normal (preterm and full-term) infants served as controls.

RESULTS AND CONCLUSION

All patients with seizures showed pathologic patterns in both the CFM and the conventional EEG tracings. The patients with ICH showed depressed amplitudes, an increase in discontinuous activity, and a high incidence of seizure activity. The patients with HIE were characterized by depressed activities correlating with the severity of the pathology. Our results indicate that the CFM is a very helpful tool for neurophysiological surveillance in high-risk neonates.

Ecological comparison of the risks of mother-to-child transmission and clinical manifestations of congenital toxoplasmosis according to prenatal treatment protocol

We compared the relative risks of mother-to-child transmission of Toxoplasma gondii and clinical manifestations due to congenital toxoplasmosis associated with intensive prenatal treatment in Lyon and Austria, short term treatment in 51% of Dutch women, and no treatment in Danish women. For each cohort, relative risks were standardized for gestation at seroconversion. In total, 856 mother-child pairs were studied: 549 in Lyon, 133 in Austria, 123 in Denmark and 51 in The Netherlands. The relative risk for mother-to-child transmission compared to Lyon was 1.24 (95% CI: 0.88, 1.59) in Austria; 0.59 (0.41, 0.81) in Denmark; and 0.65 (0.37, 1.01) in The Netherlands. Relative risks for clinical manifestations compared with Lyon (adjusted for follow-up to age 3 years) were: Austria 0.19 (0.04, 0.51); Denmark 0.60 (0.13, 1.08); and The Netherlands 1.46 (0.51, 2.72). There was no clear evidence that the risk of transmission or of clinical manifestations was lowest in centres with the most intensive prenatal treatment.

Survival after intrauterine myocardial infarction: noninvasive assessment of myocardial perfusion with 99mTc-Sestamibi scintigraphy

Survival after severe intrauterine myocardial infarction has not been reported previously. We describe the course of a neonate with a structurally normal heart, who presented with cardiogenic shock at birth due to intrauterine myocardial infarction with a huge ventricular aneurysm. Myocardial perfusion was assessed noninvasively by means of 99mTc-Sestamibi, a radiopharmaceutical agent recently introduced in nuclear cardiology to avoid repeated coronary angiography. The patient survived with improved cardiac function and normal neurodevelopmental outcome.

Ethnic differences in the frequency of the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene in healthy Israeli populations

Hyperhomocysteinemia is an independent risk factor for arteriosclerotic vascular disease. It can result from deficiencies of co-factors required for homocysteine metabolism and/or from genetic disorders of its metabolism. The association between the C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene and vascular disease is controversial, and may be affected by ethnic origin. A unique feature of the Israeli population is its ethnic diversity. The aim of this study was to study the frequency of the C677T MTHFR mutation in healthy Israeli ethnic groups. The frequency of the mutation was determined in 897 young healthy Jewish and Muslim Arab Israelis of eight different ethnic groups. Marked ethnic differences in the frequency of mutant homozygotes were found, ranging from 2% in Yemenite Jews, 4% in Sephardic Jews, 9% in Oriental Jews, 10% in Muslim Arabs, 16% in North African Jews, and 19% in Ashkenazi Jews. The frequency of mutant homozygotes was significantly higher in Ashkenazi Jews compared to Yemenites Oriental Jews, Sephardic Jews, and Muslim Arabs (chi2 = 12.35p < 0.001, chi2 = 8.17p = 0.004, chi2 = 6.04p = 0.01, chi2 = 6.54 p = 0.01, respectively). Our findings demonstrate the need for matching ethnic background in patients and controls when studying the association between the C677T MTHFR mutation and any disease.

A pulsatile pneumatically driven neonatal extracorporeal membrane oxygenation system using neck vessel cannulas tested with neonatal mock circulation

In posthypoxic circulatory failure, pulsatility of flow generated by mechanical support devices significantly influences outcome. Pneumatically driven assist devices can create highly pulsatile flow, but need large graft cannulas implanted by thoracotomy in children and neonates. Emergency application is therefore hindered. We conducted an in vitro study using neonatal mock circulation (NMC) to test whether an extracorporeal membrane oxygenation (ECMO) system driven by a commercially available pneumatic assist device also can be operated through commonly used neonatal neck vessel cannulas. Using the pneumatically operated Medos ventricular assist device (VAD) 10 ml ventricle along with the Jostra M8/HEC40 oxygenator/heat exchanger, a neonatal ECMO system was assembled and connected to the NMC by means of commercially available neonatal neck vessel cannulas. Effective ECMO flow, combined circulation flow, and circulation pressures were measured during various working settings (ventricle driving pressures [systolic/diastolic (mbar)]: low: +100/-25, moderate: +200/-50, high: +300/-99) and loading conditions (device working against 0, 50, and 100% native circulation flow). Additionally, maximum possible ECMO flow through various sizes of neonatal ECMO cannulas and resulting pressure gradients were assessed. High pressure settings were necessary to achieve 100 ml/kg/min pulsatile circulation flow in case of zero native circulation. With residual 30% native circulation flow, 100 ml/kg/min pulsatile circulation flow could be established by moderate pressure settings. Low preload or high systemic vascular resistance reduced ECMO flow markedly. We concluded that in the described setting a pneumatically driven neonatal ECMO system could be operated even through commonly used neonatal neck vessel cannulas. It was necessary to accept partial emptying of the artificial ventricle and tapering of driving pressures with increasing native circulation.

Effect of intravenous iron supplementation on erythropoiesis in erythropoietin-treated premature infants

OBJECTIVE

To test the efficacy and safety of combining intravenous iron in amounts approximating the in utero iron accretion rate and the postnatal iron loss with erythropoietin (EPO) in very low birth weight (VLBW) infants.

METHODS

A prospective, controlled, randomized, unmasked trial lasting 21 days was performed in 29 clinically stable VLBW infants <31 weeks' gestation and <1300 g birth weight not treated with red blood cell transfusions during the study period. Mean (+/- standard error of the mean) age at study entry was 23 +/- 2.9 days. After a 3-day run-in baseline period in which all participants received oral supplements of 9 mg/kg/day of iron polymaltose complex (IPC), participants were randomized to receive 18 days of treatment with: 1) oral IPC alone (oral iron group); 2) 300 U of recombinant human EPO (r-HuEPO) kg/day and daily oral IPC (EPO + oral iron group); 3) 2 mg/kg/day of intravenous iron sucrose, r-HuEPO, and oral iron (intravenous iron + EPO group). To assess efficacy of the 3 treatments, serial blood samples were analyzed for hemoglobin (Hb), hematocrit (Hct), reticulocyte count, red blood cell indices and plasma levels of transferrin, transferrin receptor (TfR), ferritin, and iron. Oxidant injury was assessed before and after treatment by plasma and urine levels of malondialdehyde (MDA) and o-tyrosine.

RESULTS

At the end of treatment, Hb, Hct, reticulocyte count, and plasma TfR were markedly higher in both of the EPO-treated groups, compared with the oral iron group. At study exit a trend toward increasing Hb and Hct levels and significantly higher reticulocyte counts were observed in the intravenous iron + EPO group, compared with the EPO + oral iron group. During treatment, plasma ferritin levels increased significantly in the intravenous iron + EPO group and decreased significantly in the other 2 groups. By the end of treatment, ferritin levels were significantly higher in the intravenous iron + EPO group compared with the other 2 groups. Although plasma and urine MDA or o-tyrosine did not differ among the 3 groups, plasma MDA was significantly greater in the subgroup of intravenous iron + EPO participants sampled at the end of the 2-hour parenteral iron infusion, compared with values observed immediately before and after parenteral iron-dosing.

CONCLUSIONS

In stable VLBW infants receiving EPO treatment, parenteral supplementation with 2 mg/kg/day of iron sucrose results in a small, but significant, augmentation of erythropoiesis beyond that of r-HuEPO and enteral iron alone. However, to reduce the potential adverse effects of parenteral iron/kg/day on increasing plasma ferritin levels and on causing oxidative injury, we suggest that the parenteral iron dose used should be reduced and/or the time of infusion extended to maintain a serum iron concentration below the total iron-binding capacity.

A solid-phase technique for preparation of no-carrier-added technetium-99m radiopharmaceuticals: application to the streptavidin/biotin system

A high effective specific activity (HESA) formulation of a biotin-containing (99m)Tc ligand [RP488: dimethyl-Gly-Ser-Cys(Acm)-Lys(Biotin)-Gly] conveniently prepared from solid phase was compared to a typical low effective specific activity (LESA) solution formulation to demonstrate improved targeting to streptavidin in an in vitro assay and in an in vivo rat model. RP488 was coupled to a maleimide-functionalized polyethylene glycol resin via a thiol ether linkage and labeled with (99m)Tc-gluconate at room temperature, followed by elution of the HESA (99m)Tc-RP488 in saline (minimum specific activity approximately 1000 TBq/mmol by amino acid analysis). Both HESA and LESA (99m)Tc-RP488 labeled at > 90% purity. In vitro, HESA (99m)Tc-RP488 incubated with streptavidin-agarose was bound quantitatively, but there was competition from addition of increasing amounts of cold RP488. In rats, radiotracer uptake was evident at the site of implantation of streptavidin-agarose beads for the HESA dose, less uptake of low effective specific activity (LESA) material, and no appreciable uptake in the control rats of the LESA or HESA dose. The target-to-background ratio for HESA (99m)Tc-RP488 was 5.4 times that of the control. The solid-phase technology offers a convenient way to prepare high specific activity receptor-targeting (99m)Tc radiopharmaceuticals.

Preterm infants with low immunoglobulin G levels have increased risk of neonatal sepsis but do not benefit from prophylactic immunoglobulin G

OBJECTIVE

In a prospective, randomized, placebo-controlled, multicenter study, we evaluated the prevention of neonatal infections with intravenous immunoglobulin G (IVIgG) prophylaxis for preterm infants (gestational age <33 weeks) with umbilical cord blood IgG levels < or =4 g/L.

STUDY DESIGN

Intravenous IgG or placebo (albumin), 1 g/kg body weight, was given on days 0, 3, 7, 14, and 21 to 81 infants with umbilical cord blood IgG levels < or =4 g/L: (1) IVIgG group, n = 40, mean (SD) gestational age 27.5 (2.2) weeks and birth weight 1.06 (0.39) kg; (2) placebo group, n = 41, mean (SD) gestational age 27.7 (2.5) weeks and birth weight 1.13 (0.38) kg. Infants with umbilical cord blood IgG levels >4 g/L (n = 238) served as a separate comparison group. Neonatal infections according to European Society of Pediatric Infectious Disease criteria were monitored until 28 days of life.

RESULTS

Infants with IgG levels < or =4 g/L at birth who received IVIgG had no significant reduction in infectious episodes or mortality rate when compared with those given placebo. However, infants with a serum concentration of IgG >4 g/L at birth had significantly fewer infectious episodes (culture-proven sepsis) than infants with low serum concentrations of IgG (< or =4 g/L) when compared at the same gestational ages (26 to 29 weeks, P <.003).

CONCLUSIONS

Prophylactic immunotherapy with IVIgG did not improve the immune competence in preterm infants with low serum IgG concentrations at birth. We speculate that a spontaneously high serum IgG concentration at birth reflects placenta function and is an indicator of a more mature immune system capable of protecting the preterm infant against severe neonatal infections.

Transvenous pacemaker leads do not worsen tricuspid regurgitation: a prospective echocardiographic study

Limited prospective data are available regarding the influence of pacemaker leads on tricuspid valve function. To examine the true incidence of these complications, 35 patients were prospectively examined by two-dimensional and Doppler echocardiography before and after implantation of either a permanent pacemaker or an automatic implantable cardioverter-defibrillator. Of the 35 patients imaged preoperatively, the amount of tricuspid regurgitation (TR) was judged as normal or trivial in 15 (43%), mild in 10 (29%), moderate in 8 (23%), and severe in 2 (6%). Following electrode implantation, TR was noted to be normal or trivial in 13 (38%), mild in 15 (48%), moderate in 6 (17%) and severe in 1 (3%). We conclude that implantation of permanent right ventricular electrodes is not usually associated with an acute worsening of tricuspid regurgitation in most patients.

Positive atrial inotropic effect of dofetilide after cardioversion of atrial fibrillation or flutter

The pure class III agent dofetilide was evaluated to determine its effect on atrial function after cardioversion of atrial fibrillation or flutter. Compared with placebo, dofetilide-treated patients had evidence of better atrial function after cardioversion, indicating that this agent has a positive atrial inotropic effect during the period of postcardioversion atrial stunning.