Neonatal Bradycardia Research Articles

Randomized Controlled Trial of Labetalol Versus Hydralazine, for Severe Hypertension in Obstetric Patients, at Tertiary Care Hospital of Karachi

Background: Blood pressure ≥160/110 mm Hg, is indication for urgent drug therapy in obstetric women, to prevent complications and deaths. There is limited data for comparison of Labetalol to Hydralazine in emergent treatment of severe pregnancy related hypertension. Methods: Randomized controlled trial, analyzed 184 women with severe hypertension at ≥28 weeks of pregnancy or within 72 hours after delivery, from October 2012 to September 2014. Ninety-two patients in each group received intravenous Labetalol or Hydralazine boluses, repeated every 10 or 20 minutes respectively (maximum 5 boluses). Outcome measures comprised blood pressure reduction <160/110 mm Hg, mean arterial pressure, severe persistent hypertension, number of boluses, maternal hypotension, tachycardia, adverse effect on fetal heart, still birth and neonatal bradycardia. Data was collected on a semi -structured proforma and analyzed through SPSS version 20. Numeric outcome measures were compared by Mann Whitney U test or independent sample t test according to normality distribution. Qualitative measures were compared by Chi square or Fisher’s exact test. Level of significance was <0.05 Results: There was no significant difference in reduction of systolic, diastolic blood pressure and severe persistent hypertension, between Labetalol and Hydralazine (p>0.05). Tachycardia, palpitation, headache, were significantly higher (p <0.05) in Hydralazine group. Adverse effects on fetal heart were not statistically significant. Numbers of boluses were significantly lower in labetalol group. Conclusion: Labetalol is equal to hydralazine in reducing severe pregnancy related hypertension. Maternal side effect profile of Labetalol is better, and it achieves blood pressure control with reduced boluses. Keywords: Pregnancy-induced hypertension, Hypertensive crisis, Labetalol, Hydralazine, Pregnancy, Preeclampsia, Antihypertensive agent.

Neonatal Lupus presenting with neonatal hemochromatosis-like liver disease that responded to steroids: a case report

BackgroundNeonatal lupus erythematosus is a rare multisystem autoimmune disorder that predominantly involves the heart with congenital heart block but can involve other organs including the liver. The disease results from passage of maternal autoantibodies to the fetus and manifests in various forms depending on the organ involved. Neonatal lupus liver disease manifestations range from benign elevation in aminotransferases to fatal hepatic insufficiency with iron deposition that does not respond to therapy. Only a handful of cases have been reported to date. The antibodies implicated are Sjogren Syndrome types A and B antibodies. Other non-specific autoantibodies can be positive as well such as antinuclear antibodies. Smooth muscle antibodies are classically considered specific to autoimmune hepatitis, and while they have been described in other chronic liver diseases, they have not been described in neonatal lupus liver disease. Herein we report a rare case of neonatal cholestasis due to neonatal lupus liver disease that presented with a positive smooth muscle antibodies in addition to a biochemical picture of neonatal hemochromatosis, with a remarkably elevated ferritin, that responded well to steroid therapy. Case presentationAn 8-day old full-term baby girl was referred to our center for evaluation of neonatal bradycardia and generalized jaundice that started in the first day of life. Prenatal history was significant for fetal bradycardia. Examination was unremarkable except for bradycardia and generalized jaundice. Laboratory findings included elevated alanine aminotransferase, aspartate aminotransferase, Alkaline Phosphatase, and total and direct bilirubin. Her ferritin was markedly elevated along with triglycerides. Sjogren syndrome antibodies were positive in addition to antinuclear and anti-smooth muscle antibodies. The diagnosis of cardiac neonatal lupus was given, and her liver disease was attributed to lupus despite the biochemical picture of neonatal hemochromatosis. She was started on oral prednisolone for which her liver function parameters showed a dramatic response and continued to be within the normal limits several weeks after discontinuation of steroids.ConclusionNeonatal lupus liver disease is a rare cause of neonatal cholestasis that can rarely present with neonatal hemochromatosis picture which unlike other causes of neonatal hemochromatosis can be reversed with steroid therapy.

Contemporary maternal and fetal outcomes in the treatment of LQTS during pregnancy: Is nadolol bad for the fetus?

β-Blocker therapy, specifically nadolol, is the recommended treatment for long QT syndrome (LQTS). Previous studies assessing maternal and fetal outcomes were published before the nadolol era. The purpose of this study was to examine contemporary maternal and fetal outcomes in the treatment of LQTS during pregnancy. We queried the Inherited Arrhythmia Database at Cleveland Clinic and identified all pregnant patients with LQTS from January 2001 through January 2020. Collected data included use and timing of β-blockers, maternal arrhythmic events, fetal growth restriction, neonatal hypoglycemia, and bradycardia. Among 68 live-birth pregnancies in 31 women with LQTS (mean age 29 ± 5.9 years; mean corrected QT interval 468 ± 39 ms), there were 5 arrhythmic events in 4 mothers. All arrhythmic events occurred in the postpartum period, and there were no arrhythmic events in patients taking β-blockers. In patients diagnosed with LQTS and treated with β-blockers (n = 27 [41%]), nadolol was the most commonly prescribed agent throughout pregnancy and the postpartum period (n = 16 [60%]). The rate of intrauterine growth restriction was not significantly different in fetuses exposed to β-blockers vs unexposed (P = .08). In the postnatal period, hypoglycemia was not seen and 1 patient in the exposure group had bradycardia. Arrhythmic events were only seen in the postpartum period in those not treated with β-blockers. Events occurred as late as 9 months postpartum. β-Blocker therapy, specifically nadolol, was not associated with a higher incidence of intrauterine growth restriction. Moreover, neonatal bradycardia was rare and hypoglycemia was not observed.

The Risk for Neonatal Hypoglycemia and Bradycardia after Beta-Blocker Use during Pregnancy or Lactation: A Systematic Review and Meta-Analysis

Beta-blockers are often used during pregnancy to treat cardiovascular diseases. The described neonatal side effects of maternal beta-blocker use are hypoglycemia and bradycardia, but the evidence base for these is yet to be evaluated comprehensively. Hence, this systematic review and meta-analysis was performed to evaluate the potential increased risk for hypoglycemia and bradycardia in neonates exposed to beta-blockers in utero or during lactation. A systematic search of English-language human studies was conducted until 21 April 2021. Both observational studies and randomized controlled trials investigating hypoglycemia and/or bradycardia in neonates following beta-blocker exposure during pregnancy and lactation were included. All articles were screened by two authors independently and eligible studies were included. Pair-wise and proportion-based meta-analysis was conducted and the certainty of evidence (CoE) was performed by standard methodologies. Of the 1.043 screened articles, 55 were included in this systematic review. Our meta-analysis showed a probable risk of hypoglycemia (CoE—Moderate) and possible risk of bradycardia (CoE—Low) in neonates upon fetal beta-blocker exposure. Therefore, we suggest the monitoring of glucose levels in exposed neonates until 24 h after birth. Due to the limited clinical implication, monitoring of the heart rate could be considered for 24 h. We call for future studies to substantiate our findings.

Risk for neonatal hypoglycaemia and bradycardia after beta-blocker use during pregnancy or lactation: a systematic review and meta-analysis protocol

IntroductionBeta-blockers are often used during pregnancy to treat diseases such as pre-existing hypertension, arrhythmias or pregnancy-related hypertension. Since beta-blockers are able to cross the placenta and can pass into breast...

Perinatal Transmission and Clinical Outcomes of Neonates Born to SARS-CoV-2-Positive Mothers.

BackgroundThe aim of the study was to investigate the clinical outcomes and rate of virus detection in neonates born to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive mothers.MethodsThis prospective study included neonates born to SARS-CoV-2-positive mothers, documenting their viral polymerase chain reaction results and clinical outcomes.ResultsOf the 130 neonates born to 122 SARS-CoV-2-positive mothers, 12% tested positive. Most (62%) neonates were delivered via cesarean section at an average gestational age of 36 weeks, with a birth weight of 2,900 g. Only 38% neonates required admission. SARS-CoV-2-positive infants were born at a significantly lower gestational age; had a significantly lower birth weight; and had significantly higher admission rates, surfactant therapy, and bradycardia than SARS-CoV-2-negative infants. There was no significant difference in mortality rates.ConclusionThis study documents perinatal transmission of SARS-CoV-2. It reports for the first time the occurrence of neonatal bradycardia as a complication of maternal SARS-CoV-2 infection. Despite that, neonates born to SARS-CoV-2-positive mothers had relatively good short-term outcomes.

Chest Compressions for Bradycardia during Neonatal Resuscitation-Do We Have Evidence?

The International Liaison Committee on Resuscitation (ILCOR) recommends the initiation of chest compressions (CC) during neonatal resuscitation after 30 s of effective ventilation if the infant remains bradycardic (defined as a heart rate less than 60 bpm). The CC are performed during bradycardia to optimize organ perfusion, especially to the heart and brain. Among adults and children undergoing cardiopulmonary resuscitation (CPR), CC is indicated only for pulselessness or poor perfusion. Neonates have a healthy heart that attempts to preserve coronary and cerebral perfusion during bradycardia secondary to asphyxia. Ventilation of the lungs is the key step during neonatal resuscitation, improving gas exchange and enhancing cerebral and cardiac blood flow by changes in intrathoracic pressure. Compressing the chest 90 times per minute without synchrony with innate cardiac activity during neonatal bradycardia is not based on evidence and could potentially be harmful. Although there are no studies evaluating outcomes in neonates, a recent pediatric study in a hospital setting showed that when CC were initiated during pulseless bradycardia, a third of the patients went into complete arrest, with poor survival at discharge. Ventilation-only protocols such as helping babies breathe are effective in reducing mortality and stillbirths in low-resource settings. In a situation of complete cardiac arrest, CC reinitiates pulmonary flow and supports gas exchange. However, the benefit/harm of performing asynchronous CC during bradycardia as part of neonatal resuscitation remains unknown.

Gene-environment interactions in antisocial behavior are mediated by early-life 5-HT2A receptor activation

The ontogeny of antisocial behavior (ASB) is rooted in complex gene-environment (G×E) interactions. The best-characterized of these interplays occurs between: a) low-activity alleles of the gene encoding monoamine oxidase A (MAOA), the main serotonin-degrading enzyme; and b) child maltreatment. The purpose of this study was to develop the first animal model of this G×E interaction, to help understand the neurobiological mechanisms of ASB and identify novel targets for its therapy. Maoa hypomorphic transgenic mice were exposed to an early-life stress regimen consisting of maternal separation and daily intraperitoneal saline injections and were then compared with their wild-type and non-stressed controls for ASB-related neurobehavioral phenotypes. Maoa hypomorphic mice subjected to stress from postnatal day (PND) 1 through 7 – but not during the second postnatal week - developed overt aggression, social deficits and abnormal stress responses from the fourth week onwards. On PND 8, these mice exhibited low resting heart rate - a well-established premorbid sign of ASB – and a significant and selective up-regulation of serotonin 5-HT2A receptors in the prefrontal cortex. Notably, both aggression and neonatal bradycardia were rescued by the 5-HT2 receptor antagonist ketanserin (1–3 mg kg−1, IP), as well as the selective 5-HT2A receptor blocker MDL-100,907 (volinanserin, 0.1–0.3 mg kg−1, IP) throughout the first postnatal week. These findings provide the first evidence of a molecular basis of G×E interactions in ASB and point to early-life 5-HT2A receptor activation as a key mechanism for the ontogeny of this condition.This article is part of the Special Issue entitled ‘The neuropharmacology of social behavior: from bench to bedside’.

Erythromycin and Reflux Events in Premature Neonates: A Randomized Clinical Trial.

Gastroesophageal reflux disease (GERD) in premature neonates may manifest as apnea, bradycardia, growth failure, aspiration, or feeding intolerance. Erythromycin ethylsuccinate (EES), is often used as a pro-kinetic in the management of GERD, despite lack of evidence or safety from randomized controlled trials. We sought to study the efficacy of enteral EES at a dose of 50 mg · kg · day in decreasing the frequency of gastroesophageal reflux events as determined by pH-multichannel intraluminal impedance (pH-MII) monitoring. In a randomized, double-blind, placebo-controlled trial, eligible premature neonates with clinical signs of GERD underwent 24-hour pH-MII monitoring. If >5 reflux events were identified on pH-MII, then subjects were randomized to receive either EES or placebo. Repeat 24-hour pH-MII was performed on day 7 of study treatment and compared to initial pH-MII. Forty-three premature neonates were enrolled. Of those, 31 neonates were randomized, 15 to EES and 16 to placebo with a median (IQR) pretreatment total reflux events per 24 hours of 23 (16-40) and 29 (12-40), respectively. Day 7 total events per 24 hours decreased by 4 events in the EES group to 19 (15-33) and by 10 events in the placebo group to 19 (11-26) (P = 0.09). There were no differences in pretreatment and day 7 acidic and nonacidic reflux, proximal reflux, total or percent reflux time, median or longest bolus clearance time, or nurse-reported apnea events between groups. Enteral EES did not decrease reflux events on 24-hour pH-MII at the dose studied. Therefore, it may be ineffective in the treatment of GERD in premature neonates.

Biallelic SCN10A mutations in neuromuscular disease and epileptic encephalopathy.

ObjectivesTwo consanguineous families, one of Sudanese ethnicity presenting progressive neuromuscular disease, severe cognitive impairment, muscle weakness, upper motor neuron lesion, anhydrosis, facial dysmorphism, and recurrent seizures and the other of Egyptian ethnicity presenting with neonatal hypotonia, bradycardia, and recurrent seizures, were evaluated for the causative gene mutation.Methods and ResultsHomozygosity mapping and whole exome sequencing (WES) identified damaging homozygous variants in SCN10A, namely c.4514C>T; p.Thr1505Met in the first family and c.4735C>T; p.Arg1579* in the second family. A third family, of Western European descent, included a child with febrile infection‐related epilepsy syndrome (FIRES) who also had compound heterozygous missense mutations in SCN10A, namely, c.3482T>C; p.Met1161Thr and c.4709C>A; p.Thr1570Lys. A search for SCN10A variants in three consortia datasets (EuroEPINOMICS, Epi4K/EPGP, Autism/dbGaP) identified an additional five individuals with compound heterozygous variants. A Hispanic male with infantile spasms [c.2842G>C; p.Val948Leu and c.1453C>T; p.Arg485Cys], and a Caucasian female with Lennox–Gastaut syndrome [c.1529C>T; p.Pro510Leu and c.4984G>A; p.Gly1662Ser] in the epilepsy databases and three in the autism databases with [c.4009T>A; p.Ser1337Thr and c.1141A>G; p.Ile381Val], [c.2972C>T; p.Pro991Leu and c.2470C>T; p.His824Tyr], and [c.4009T>A; p.Ser1337Thr and c.2052G>A; p.Met684Ile].Interpretation SCN10A is a member of the voltage‐gated sodium channel (VGSC) gene family. Sodium channels are responsible for the instigation and proliferation of action potentials in central and peripheral nervous systems. Heterozygous mutations in VGSC genes cause a wide range of epileptic and peripheral nervous system disorders. This report presents autosomal recessive mutations in SCN10A that may be linked to epilepsy‐related phenotypes, Lennox–Gastaut syndrome, infantile spasms, and Autism Spectrum Disorder.

A Model Practice Template for Hydrotherapy in Labor and Birth.

A Model Practice Template for Hydrotherapy in Labor and Birth.

Late Pregnancy β Blocker Exposure and Risks of Neonatal Hypoglycemia and Bradycardia.

β blockers are widely used in the treatment of hypertensive disorders during pregnancy. These medications cross the placenta and may cause physiologic changes in neonates exposed in utero. We sought to define the risks of neonatal hypoglycemia and bradycardia associated with maternal exposure to β blockers at the time of delivery in a large, nationwide cohort of Medicaid beneficiaries. We used a cohort of 2 292 116 completed pregnancies linked to liveborn infants of Medicaid-enrolled women from 2003 to 2007. We examined the risks of neonatal hypoglycemia and neonatal bradycardia associated with maternal exposure to β blockers at the time of delivery. Propensity score matching was used to control for potential confounders including maternal demographics, obstetric and medical conditions, and exposure to other medications. There were 10 585 (0.5%) pregnancies exposed to β blockers at the time of delivery. The risk of neonatal hypoglycemia was 4.3% in the β blocker-exposed neonates versus 1.2% in the unexposed; the risk of neonatal bradycardia was 1.6% in the exposed versus 0.5% in the unexposed. After controlling for confounders, risk remained elevated for both neonatal hypoglycemia and bradycardia among exposed pregnancies versus unexposed (adjusted odds ratio, 1.68, 95% confidence interval, 1.50-1.89 and adjusted odds ratio, 1.29, 95% confidence interval, 1.07-1.55, respectively). Our findings suggest that neonates born to mothers exposed to β blockers in late pregnancy, including labetalol, are at elevated risk for neonatal hypoglycemia and bradycardia.

Neuromodulation of Limb Proprioceptive Afferents Decreases Apnea of Prematurity and Accompanying Intermittent Hypoxia and Bradycardia.

BackgroundApnea of Prematurity (AOP) is common, affecting the majority of infants born at <34 weeks gestational age. Apnea and periodic breathing are accompanied by intermittent hypoxia (IH). Animal and human studies demonstrate that IH exposure contributes to multiple pathologies, including retinopathy of prematurity (ROP), injury to sympathetic ganglia regulating cardiovascular action, impaired pancreatic islet cell and bone development, cerebellar injury, and neurodevelopmental disabilities. Current standard of care for AOP/IH includes prone positioning, positive pressure ventilation, and methylxanthine therapy; these interventions are inadequate, and not optimal for early development.ObjectiveThe objective is to support breathing in premature infants by using a simple, non-invasive vibratory device placed over limb proprioceptor fibers, an intervention using the principle that limb movements trigger reflexive facilitation of breathing.MethodsPremature infants (23–34 wks gestational age), with clinical evidence of AOP/IH episodes were enrolled 1 week after birth. Caffeine treatment was not a reason for exclusion. Small vibration devices were placed on one hand and one foot and activated in 6 hour ON/OFF sequences for a total of 24 hours. Heart rate, respiratory rate, oxygen saturation (SpO2), and breathing pauses were continuously collected.ResultsFewer respiratory pauses occurred during vibration periods, relative to baseline (p<0.005). Significantly fewer SpO2 declines occurred with vibration (p<0.05), relative to control periods. Significantly fewer bradycardic events occurred during vibration periods, relative to no vibration periods (p<0.05).ConclusionsIn premature neonates, limb proprioceptive stimulation, simulating limb movement, reduces breathing pauses and IH episodes, and lowers the number of bradycardic events that accompany aberrant breathing episodes. This low-cost neuromodulatory procedure has the potential to provide a non-invasive intervention to reduce apnea, bradycardia and intermittent hypoxia in premature neonates.Trial RegistrationClinicalTrials.gov NCT02641249

Evaluation and management of bradycardia in neonates and children.

Early diagnosis and appropriate management are critical in many cases in order to prevent sudden death, and this review critically assesses our current practice for evaluation and management of bradycardia in neonates and children. Bradycardia is defined as a heart rate below the lowest normal value for age. Age related changes in the anatomy and physiology of infants and children produce normal ranges for electrocardiogram features that differ from adults and vary with age. Pediatric bradycardia most commonly manifests as sinus bradycardia, junctional bradycardia, or atrioventricular block. Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause. Bradycardia may occur in a structurally normal heart or in association with congenital heart disease. Genetic variants in multiple genes have been described. Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia. Early diagnosis and appropriate management are critical in order to prevent sudden death.

Comparative Study of Efficacy and Safety of Intravenous Labetalol and Intravenous Hydralazine in managing Hypertensive Emergencies in Pregnancy

ABSTRACT Objectives Evaluation of efficacy and safety of intravenous labetalol and intravenous hydralazine in managing hypertensive emergency in pregnancy. Study design An open, randomized comparison of intravenous labetatol vs intravenous hydralazine was conducted in 100 pregnant women presenting with hypertensive emergency during pregnancy. Materials and methods: Inclusion criteria Women with severe hypertension in pregnancy at 34 weeks of gestation or more, i.e., systolic BP ≥160 mm Hg or diastolic BP ≥ 110 mm Hg with or without proteinuria either in labor or not in labor. Results The antihypertensive efficacy of both the drugs was found to be comparable. The primary outcome in terms of BP control was achieved in both the groups. There were four treatment failures in labetalol group and none in hydralazine group. No significant difference was observed in maternal and fetal outcomes. Palpitation and tachycardia occurred significantly more often in patients treated with hydralazine. Bradycardia was significantly more frequent in labetalol group. The neonatal outcomes were similar per group. Conclusion The randomized clinical trial showed that labetalol and hydralazine fulfil the criteria required for an antihypertensive drug to treat severe hypertension in pregnancy. Hydralazine has its side effects like palpitation, headache, oliguria, dizziness, muscle cramps, and nasal congestion, which mimic symptoms of deteriorating pre-eclampsia. Labetalol has a better side effect profile, but specific concerns have been raised about the risk of neonatal bradycardia. How to cite this article Singh R, Singh S, Singh S, Agarwal M, Anand S, Yadav NK. Comparative Study of Efficacy and Safety of Intravenous Labetalol and Intravenous Hydralazine in managing Hypertensive Emergencies in Pregnancy. J South Asian Feder Obst Gynae 2016;8(3):185-188.

English

Most common cause of bradycardia in newborn is sinus bradycardia due to hypoxia and acidosis. Complete Congenital Heart block (CCHB)is a rare cause of neonatal bradycardia. We are here with reporting a rare case of NLE, which presented with birth asphyxia and bradycardia, not responding to resuscitation. The baby had CHB with cardiogenic shock and was initially stabilized

A rare cause of neonatal bradycardia: Blocked atrial bigeminal beat

Bradycardia is defined as a heart rate below the lowest normal value adjusted for age. It is caused by intrinsic dysfunction, injury to the heart’s conduction system or by extrinsic factors acting on a normal heart and its conduction system (1). Premature atrial contractions (PACs), are a rare cause of bradycardia. A slow heart rate may occur in that the sinus node discharges a PAC that’s blocked before causing the atria to contract (2,3). Herein, we report a newborn with frequent premature atrial contractions in bigeminal pattern. The bradycardiac patient with bradycardia was successfully treated with propafenone. Herein, we present the case of a 10-day-old infant that was referred to our department for bradycardia. A female neonate of 3100 gr and Apgar score of 8/10 at 1/5 minutes was born by normal spontaneous vaginal delivery at 39. gestational weeks. Her physical examination was normal except bradycardia. Pulse rate was 72 bpm, and blood pressure was 68/32 mmHg. Careful review of her electrocardiogram (ECG) revealed that closely coupled bigeminy PACs were blocked at the atrioventricular junction, mimicking severe sinus bradycardia (Figure 1). No significant abnormalities were found on her echocardiogram, and laboratory test results (complete blood count, biochemical panel and brain natriuretic peptide) were normal. Holter ECG monitoring showed a sinus rhythm with very frequent blocked atrial bigeminy, and short runs of atrial tachycardia. Mean heart rate was 83 bpm, while the minimal, and maximal heart rates was 63 bpm, and 98 bpm, respectively. An antiarrhythmic medication (propranolol) was started without any improvement in the antiarrhytmic control. This treatment was stopped and therapy with propafenone (300 mg/m2/d) was initiat-

Actocardiographic Analysis of Fetal Hypoxia Detected by the Bradycardia, Loss of Fetal Heart Rate Acceleration, and Long Term Variability

Aims: To clarify the mechanism of hypoxic Fetal Heart Rate (FHR) by the actocardio-gram. Methods: Hypoxic rabbit heart rate and PaO 2 were studied. Long Term FHR Variability (LTV) was studied in physiologic sinusoidal FHR and anencephalic fetus, the acceleration in hypoxia, and by its electronic simulation and adult heart rate. Results: Anencephalic neonatal bradycardia was caused by the excitation of remained medulla oblongata. Rabbit's bradycardia was parallel to PaO 2 bunder 50 mm Hg, which disappeared after urethane anesthesia. Human fetal bradycardia was caused by the hypoxia, because fetal PaO2 is less than 50 mm Hg. FHR acceleration was evoked in the midbrain by the large fetal movement bursts, and minor movements evoked LTV. Physiological sinusoidal FHR was a particular form of LTV. Triangular acceleration was simulated by the electronic integral circuit, and by the triangular heart rate in adult exercises. Fetal outcome was correlated to the acceleration duration. Hypoxia damaged fetal brain in nonreactive FHR, loosing acceleration, and advanced hypoxia further damaged brain a few days after the loss of acceleration, showing the loss of LTV and bradycardia. The loss of LTV which was confirmed by the frequency power spectrum was rare, but its brain damage was as severe as the apnea of anencephalic neonate, which lost cerebral respiratory center. Conclusion: Hypoxic bradycardia was evoked by the excited medulla oblongata in the decreased PaO 2 , which was lower than 50 mm Hg. The hypoxia damaged fetus in fetal bradycardia, the losses of acceleration and LTV, in relation to fetal movements.

Effect of hypoxic myocardial injury on neonatal cerebral hemodynamics and brain tissue oxygen saturation

Objective To investigate the effect of neonatal hypoxic myocardial injury and bradycardia on cerebral hemodynamics and brain tissue regional oxygen saturation (rSO2),and to provide patho-physiological evidence for treatment of neonatal hypoxic-ischemic encephalopathy (HIE) in acute phase.Methods Ninety nine full-term newborns admitted into Department of Neonatology,Peking University First Hospital from December,2005 to December,2008 were enrolled in this study.There were 18 newborns with both myocardial injury and HIE (group 1),31 newborns with HIE but without myocardial injury (group 2) and 50 cases of neonatal jaundice (control group).From 3 to 7 days after birth,Doppler ultrasound was used to measure systolic velocity (Vs),diastolic velocity (Vd) and resistance index (RI) of the anterior cerebral artery; and brain tissue rSO2 was detected by near infrared spectroscopy.The differences among groups were compared by variance analysis and LSD test.Brain tissue rSO2 before and after treatment of 20 newborns with bradycardia for various causes were detected and the difference was compared by paired t test.Results (1) Vs of group 1,group 2 and the control group was (19.35±5.13),(29.35±4.28) and (32.62±7.47) cm/s respectively; Vd was (6.43±2.98),(11.21±3.16) and (11.50±3.03) cm/s; RI was 0.68±0.10,0.62±0.03 and 0.64±0.06; brain tissue rSO2 was (52.4± 2.8)％,(54.6±3.1)％ and (62.1±1.9)％.There were significant differences among the three group(F=29.999,19.393,5.283 and 137.952,P＜0.01).Vs,Vd and rSO2 of group 1 were lower than that of group 2 and the control group (P＜0.05).RI of group 1 was higher than that of group 2 and the control group (P＜0.05).Vs and rSO2 of group 2 were lower than that of control group,but there were no differences between the two groups in Vd and RI.(2) The brain tissue rSO2 of newborns with bradycardia after treatment was higher than that before treatment [(58.7±4.6)％ vs (50.9±3.2)％,t=6.239,P＜0.01].Conclusions The disturbance of cerebral hemodynamics and cerebral oxygenation in HIE newborns are aggravated by hypoxic myocardial injury.Stable heart rate might be very important to early treatment for HIE. Key words: Anoxia; Cardiomyopathies; Bradycardia; Hemodynamics; Hypoxia-ischemia,brain; Oxygen

Closed versus Open Endotracheal Suctioning in Extremely Low-Birth-Weight Neonates: A Randomized, Crossover Trial

Background: Endotracheal suctioning, which is frequently necessary in mechanically ventilated patients, might cause complications, especially in patients with compromised lung function such as extremely low-birth-weight (ELBW) neonates. Objectives: To investigate whether closed endotracheal suctioning (CS) reduces the frequency of hypoxemia and bradycardia in ELBW neonates compared to open suctioning (OS). Methods: In a randomized, crossover trial, 15 ventilated ELBW neonates (mean birth weight 655 g) underwent suctioning with both techniques. Data on oxygen saturation (Sp<smlcap>o</smlcap>₂), heart rate (HR), arterial blood pressure, arterial blood gases, duration of the suctioning procedure and recovery time were collected. Statistical analysis was done using the SPSS t test for paired samples. Results: The mean frequency of hypoxemia <85% was significantly decreased (p = 0.012) during CS (0.5) versus OS (1.1). The mean minimum Sp<smlcap>o</smlcap>₂ was significantly higher (p = 0.012) during CS (87%) compared to OS (84%), and a significantly less steep drop in mean Sp<smlcap>o</smlcap>₂ (p = 0.007) (CS: –5%, OS: –8%) was found. Mean arterial P<smlcap>o</smlcap>₂ (p = 0.035; CS: 59 mm Hg, OS: 53 mm Hg) and mean oxygenation ratio (p = 0.016; CS: 197, OS: 171) were significantly higher after CS. No significant differences were found in HR, incidence or duration of bradycardia, recovery time, arterial blood pressure, duration of suctioning, number of complications, or duration of hypoxemia. Conclusion: CS was superior to OS on oxygenation values. To prove its overall superiority, further research is required. So, in this group of patients, CS should currently be administered on an individual basis.