Resuscitation of the term and preterm infant

[Telemedical support of feto-neonatal care in one region - Part II: Structural requirements and areas of application in neonatology]

Telemedical infrastructure for patient assessment, care and follow-up as well as interdisciplinary exchange can contribute to ensuring patient care that is close to home and meets the highest quality standards, even outside specialised centres. In neonatology, synchronous audio-visual communication across institutions has been used for many years, especially in the Anglo-American countries. Areas of application include extended neonatal primary care and resuscitation, specific diagnostic applications, e.g. ROP screening and echocardiography, as well as parental care, regular telemedical ward rounds and further training of medical staff, especially using simulation training. For the implementation of such telemedical infrastructures, certain organisational, medical-legal and technical requirements for hardware, software and structural and process organisation must be met. The concrete realisation of a telemedical infrastructure currently being implemented for the region of Eastern Saxony is demonstrated here using the example of the Saxony Center for feto/neonatal Health (SCFNH). Within the framework of feto-neonatal competence networks such as the SCFNH, the quality of medical care, patient safety and satisfaction in a region can be increased by means of a comprehensive, well-structured and established telemedical infrastructure.

Tactile stimulation in the delivery room: past, present, future. A systematic review

In current resuscitation guidelines, tactile stimulation is recommended for infants with insufficient respiratory efforts after birth. No recommendations are made regarding duration, onset, and method of stimulation. Neither is mentioned how tactile stimulation should be applied in relation to the gestational age. The aim was to review the physiological mechanisms of respiratory drive after birth and to identify and structure the current evidence on tactile stimulation during neonatal resuscitation. A systematic review of available data was performed using PubMed, covering the literature up to April 2021. Two independent investigators screened the extracted references and assessed their methodological quality. Six studies were included. Tactile stimulation management, including the onset of stimulation, overall duration, and methods as well as the effect on vital parameters was analyzed and systematically presented. Tactile stimulation varies widely between, as well as within different centers and no consensus exists which stimulation method is most effective. Some evidence shows that repetitive stimulation within the first minutes of resuscitation improves oxygenation. Further studies are warranted to optimize strategies to support spontaneous breathing after birth, assessing the effect of stimulating various body parts respectively within different gestational age groups.

Survey on currently applied interventions in neonatal resuscitation (SCIN): A study protocol

INTRODUCTION

Around 140 million children are born every year and post-natal transition is uncomplicated in the vast majority. However, around 5%-15% of neonates receive supportive interventions during transition. Recent data on the interventions used is scarce. More data on the frequencies with which these interventions are used is needed to evaluate neonatal resuscitation, guide recommendations and to generate hypotheses for further research. The following protocol describes an international, multicentre survey on the interventions currently applied during neonatal resuscitation.

OBJECTIVES

To determine the frequencies at which different supportive interventions recommended by European Resuscitation Council (ERC) guidelines for neonatal resuscitation are used. To compare the frequencies between hospitals and patient groups and to investigate possible factors influencing any differences found.

METHODS

Participating hospitals will collect data on all interventions performed during neonatal resuscitation over a period of 6 months. All hospitals providing perinatal care are eligible regardless of size and designated level of neonatal care. Every neonate requiring more interventions than basic drying and tactile stimulation during the first 30 min of life will be included. The targeted sample size is at least 4,000 neonates who receive interventions. After anonymization, the data is pooled in a common database and descriptive and statistical analysis is performed globally and in subgroups. Possible correlations will be investigated with phi coefficient and chi square testing.

ETHICS AND DISSEMINATION

Consent of the institutional review board of the Technical University Dresden was obtained for the local data collection under the number BO-EK-198042022. Additionally, approval of local ethical or institutional review boards will be obtained by the participating hospitals if required. Results will be published in peer-reviewed journals and presented at suitable scientific conferences.

Cardiorespiratory monitoring in the delivery room using transcutaneous electromyography

OBJECTIVE

To assess feasibility of transcutaneous electromyography of the diaphragm (dEMG) as a monitoring tool for vital signs and diaphragm activity in the delivery room (DR).

DESIGN

Prospective observational study.

SETTING

Delivery room.

PATIENTS

Newborn infants requiring respiratory stabilisation after birth.

INTERVENTIONS

In addition to pulse oximetry (PO) and ECG, dEMG was measured with skin electrodes for 30 min after birth.

OUTCOME MEASURES

We assessed signal quality of dEMG and ECG recording, agreement between heart rate (HR) measured by dEMG and ECG or PO, time between sensor application and first HR read-out and agreement between respiratory rate (RR) measured with dEMG and ECG, compared with airway flow. Furthermore, we analysed peak, tonic and amplitude diaphragmatic activity from the dEMG-based respiratory waveform.

RESULTS

Thirty-three infants (gestational age: 31.7±2.8 weeks, birth weight: 1525±661 g) were included.18%±14% and 22%±21% of dEMG and ECG data showed poor quality, respectively. Monitoring HR with dEMG was fast (median 10 (IQR 10-11) s) and accurate (intraclass correlation coefficient (ICC) 0.92 and 0.82 compared with ECG and PO, respectively). RR monitoring with dEMG showed moderate (ICC 0.49) and ECG low (ICC 0.25) agreement with airway flow. Diaphragm activity started high with a decreasing trend in the first 15 min and subsequent stabilisation.

CONCLUSION

Monitoring vital signs with dEMG in the DR is feasible and fast. Diaphragm activity can be detected and described with dEMG, making dEMG promising for future DR studies.

Sustained Inflation Reduces Pulmonary Blood Flow during Resuscitation with an Intact Cord

The optimal timing of cord clamping in asphyxia is not known. Our aims were to determine the effect of ventilation (sustained inflation-SI vs. positive pressure ventilation-V) with early (ECC) or delayed cord clamping (DCC) in asphyxiated near-term lambs. We hypothesized that SI with DCC improves gas exchange and hemodynamics in near-term lambs with asphyxial bradycardia. A total of 28 lambs were asphyxiated to a mean blood pressure of 22 mmHg. Lambs were randomized based on the timing of cord clamping (ECC-immediate, DCC-60 s) and mode of initial ventilation into five groups: ECC + V, ECC + SI, DCC, DCC + V and DCC + SI. The magnitude of placental transfusion was assessed using biotinylated RBC. Though an asphyxial bradycardia model, 2-3 lambs in each group were arrested. There was no difference in primary outcomes, the time to reach baseline carotid blood flow (CBF), HR ≥ 100 bpm or MBP ≥ 40 mmHg. SI reduced pulmonary (PBF) and umbilical venous (UV) blood flow without affecting CBF or umbilical arterial blood flow. A significant reduction in PBF with SI persisted for a few minutes after birth. In our model of perinatal asphyxia, an initial SI breath increased airway pressure, and reduced PBF and UV return with an intact cord. Further clinical studies evaluating the timing of cord clamping and ventilation strategy in asphyxiated infants are warranted.

T-piece resuscitator or self-inflating bag during neonatal resuscitation: a scoping review

BACKGROUND

To identify the evidence for administering positive pressure ventilation (PPV) to infants at birth by either T-piece resuscitator (TPR) or self-inflating bag (SIB), and to determine whether a full systematic review (SR) is warranted.

METHODS

Guided by the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for scoping reviews, eligible studies included peer-reviewed human studies, prospectively or retrospectively comparing a TPR vs. SIB for administering PPV at birth. Databases searched were OVID Medline, PubMed, Embase and the Cochrane Central Register of Controlled Trials. Review Manager software was used for the data analysis.

RESULTS

Following electronic literature search and review, data from four eligible studies (3 RCT and 1 observational study), enrolling a total of 2889 patients, were included. Studies differed regarding the investigated populations, reported outcomes and came from different geographical areas. In particular for preterm infants, use of TPR for providing PPV may improve survival, result in fewer intubations at birth and decrease the incidence of bronchopulmonary dysplasia.

CONCLUSIONS

This scoping review identified two new studies with substantive new evidence, pointing towards improved survival, decreased bronchopulmonary dysplasia and fewer intubations at birth, in particular among preterm infants treated with TPR. Full SR of the literature is advised.

IMPACT

This scoping review identified studies comparing TPR vs. SIB for respiratory support of newborn infants previously not included in the International Liaison Committee on Resuscitation (ILCOR) recommendations. Our review found substantive new evidence highlighting that device choice may impact the outcomes of compromised newborn infants'. This scoping review stipulates the need for full SR and updated meta-analysis of studies investigating supportive equipment for stabilizing infants at birth in order to inform ILCOR treatment recommendations.

Mechanistic actions of oxygen and methylxanthines on respiratory neural control and for the treatment of neonatal apnea

Apnea remains one of the most concerning and prevalent respiratory disorders spanning all ages from infants (particularly those born preterm) to adults. Although the pathophysiological consequences of apnea are fairly well described, the neural mechanisms underlying the etiology of the different types of apnea (central, obstructive, and mixed) still remain incompletely understood. From a developmental perspective, however, research into the respiratory neural control system of immature animals has shed light on both central and peripheral neural pathways underlying apnea of prematurity (AOP), a highly prevalent respiratory disorder of preterm infants. Animal studies have also been fundamental in furthering our understanding of how clinical interventions (e.g. pharmacological and mechanical) exert their beneficial effects in the clinical treatment of apnea. Although current clinical interventions such as supplemental O₂ and positive pressure respiratory support are critically important for the infant in respiratory distress, they are not fully effective and can also come with unfortunate, unintended (and long-term) side-effects. In this review, we have chosen AOP as one of the most common clinical scenarios involving apnea to highlight the mechanistic basis behind how some of the interventions could be both beneficial and also deleterious to the respiratory neural control system. We have included a section on infants with critical congenital heart diseases (CCHD), in whom apnea can be a clinical concern due to treatment with prostaglandin, and who may benefit from some of the treatments used for AOP.

Devices used for stabilisation of newborn infants at birth

This review examines devices used during newborn stabilisation. Evidence for their use to optimise the thermal, respiratory and cardiovascular management in the delivery room is presented. Mechanisms of action and rationale of use are described, current developments are presented and areas of future research are highlighted.

Factors Affecting the Target Oxygen Saturation in the First Minutes of Life in Preterm Infants

BACKGROUND

The aim of this study was to describe the effect of factors on time to reach a pulse oxygen saturation (SpO2) level of 90% in preterm infants in the delivery room.

METHODS

Preterm (<35 gestational age) infants who did not require supplemental oxygen were included in the study. Continuous recordings were taken by pulse oximetry during the first 15 min of life.

RESULTS

Of 151 preterm infants, 79 (52.3%) were female and 126 (83.5%) were delivered by cesarean section. Target saturation level (≥90%) was achieved faster in preductal measurements. Mean times taken to have a preductal and postductal SpO2 level of 90% were significantly lower in preterm babies born by vaginal delivery, with umbilical arterial pH ≥ 7.20 and whose mothers were non-smokers during pregnancy.

CONCLUSIONS

Differences in achievement of target saturation level were influenced by multiple factors (birth way, probe location, maternal smoking and umbilical blood gas pH) in the delivery room during resuscitation of preterm babies.

Fetal Physiology and the Transition to Extrauterine Life

The physiology of the fetus is fundamentally different from the neonate, with both structural and functional distinctions. The fetus is well-adapted to the relatively hypoxemic intrauterine environment. The transition from intrauterine to extrauterine life requires rapid, complex, and well-orchestrated steps to ensure neonatal survival. This article explains the intrauterine physiology that allows the fetus to survive and then reviews the physiologic changes that occur during the transition to extrauterine life. Asphyxia fundamentally alters the physiology of transition and necessitates a thoughtful approach in the management of affected neonates.

Quality improvement project: implementing guidelines supporting noninvasive respiratory management for premature infants

PURPOSE

Based on research evidence, the purpose was to implement noninvasive approaches in the initial respiratory stabilization of preterm infants.

DESIGN

Quality improvement project.

SAMPLE

One hundred fourteen infants admitted to the neonatal intensive care nursery (NICN) from January 1, 2012 to May 31, 2012 served as a historical control group. Ninety-four infants admitted from January 1, 2013 to May 31, 2013 served as the intervention group.

RESULTS

After implementation of the quality improvement initiative, there was a statistically significant increase in the rate of using continuous positive airway pressure (CPAP ) by 65.3 percent for initial respiratory stabilization of preterm infants.

Neonatal resuscitation adhering to oxygen saturation guidelines in asphyxiated lambs with meconium aspiration

BACKGROUND

The Neonatal Resuscitation Program (NRP) recommends upper and lower limits of preductal saturations (SpO2) extrapolated from studies in infants resuscitated in room air. These limits have not been validated in asphyxia and lung disease.

METHODS

Seven control term lambs delivered by cesarean section were ventilated with 21% O2. Thirty lambs with asphyxia with meconium aspiration were randomly assigned to resuscitation with 21% O2 (n = 6), 100% O2 (n = 6), or initiation with 21% O2 followed by variable FIO2 to maintain NRP target SpO2 ranges (n = 18). Hemodynamic and ventilation parameters were recorded for 15 min.

RESULTS

Control lambs maintained preductal SpO2 near the lower limit of NRP target range. Asphyxiated lambs had low SpO2 (38 ± 2%), low arterial pH (6.99 ± 0.01), and high PaCO2 (96 ± 7 mm Hg) at birth. Resuscitation with 21% O2 resulted in SpO2 values below the target range with low pulmonary blood flow (Qp) compared to variable FIO2 group. The increase in PaO2 and Qp with variable FIO2 resuscitation was similar to control lambs.

CONCLUSION

Maintaining SpO2 as recommended by NRP by actively adjusting inspired O2 leads to effective oxygenation and higher Qp in asphyxiated lambs with lung disease. Our findings support the current NRP SpO2 guidelines for O2 supplementation during resuscitation of an asphyxiated neonate.

Cardiorespiratory Monitoring during Neonatal Resuscitation for Direct Feedback and Audit

Neonatal resuscitation is one of the most frequently performed procedures, and it is often successful if the ventilation applied is adequate. Over the last decade, interest in seeking objectivity in evaluating the infant's condition at birth or the adequacy and effect of the interventions applied has markedly increased. Clinical parameters such as heart rate, color, and chest excursions are difficult to interpret and can be very subjective and subtle. The use of ECG, pulse oximetry, capnography, and respiratory function monitoring can add objectivity to the clinical assessment. These physiological parameters, with or without the combination of video recordings, can not only be used directly to guide care but also be used later for audit and teaching purposes. Further studies are needed to investigate whether this will improve the quality of delivery room management. In this narrative review, we will give an update of the current developments in monitoring neonatal resuscitation.

Delivery room management of extremely low birth weight infants in Italy: comparison between academic and non-academic birth centres

OBJECTIVE

International Guidelines provide a standardised approach to newborn resuscitation in the DR and, in their most recent versions, recommendations dedicated to management of ELBWI were progressively increased. It is expected that introduction in clinical practice and dissemination of the most recent evidence should be more consistent in academic than in non-academic hospitals. The aim of the study was to compare adherence to the International Guidelines and consistency of practice in delivery room management of extremely low birth weight infants between academic and non-academic institutions.

METHODS

A questionnaire was sent to the directors of all Italian level III centres between April and August 2012.

RESULTS

There was a 92% (n = 98/107) response rate. Apart from polyethylene wrapping to optimise thermal control, perinatal management approach was comparable between academic and non-academic centres.

CONCLUSIONS

There were minor differences in management of extremely low birth weight infants between Italian academic and non-academic institutions, apart from thermal management. Although there was a good, overall adherence to the International Guidelines for Neonatal Resuscitation, temperature management was not in accordance with official recommendations and every effort has to be done to improve this aspect.

Effects of chest compressions on cardiovascular and cerebral hemodynamics in asphyxiated near-term lambs

BACKGROUND

Chest compressions (CC) and adrenaline administration are recommended in asphyxiated newborns with persistent bradycardia despite effective ventilation. The effects of CC on cerebral blood flow in newborns at birth are unknown. Our aim was to determine the effects of CC, with or without adrenaline administration, on the return of spontaneous circulation, carotid blood flow (CBF), and carotid arterial pressure (CAP) in asphyxiated near-term lambs.

METHODS

Asphyxia was induced in near-term lambs by clamping the umbilical cord and delaying ventilation onset until spontaneous circulation ceased. Lambs were then resuscitated by positive pressure ventilation along with CC followed by adrenaline administration. CAP and CBF were continuously recorded.

RESULTS

Mean CAP did not increase significantly during CC and only increased following adrenaline administration. CC did not increase mean CBF but increased CBF amplitude due to increased peak flow and the onset of retrograde flow during diastole. Adrenaline increased mean CBF from 1 ± 2 to 15 ± 5 ml/kg/min and abolished retrograde diastolic CBF, leading to the return in spontaneous circulation.

CONCLUSION

We conclude that CC with adrenaline administration was required to increase CBF and restore spontaneous circulation in asphyxiated lambs. Low CBF and retrograde diastolic CBF during CC indicate hypoperfusion to the brain.

Managing preterm infants in the first minutes of life

Premature infants often experience difficulties adapting to postnatal life. The most relevant ones are related to establishing an adult type cardiorespiratory circulation and acquiring hemodynamic stability, aerating the lung and attaining a functional residual capacity, performing an adequate gas exchange and switching to an oxygen enriched metabolism, and keeping an adequate body temperature. In recent years a body of evidence supports a trend towards gentle management in the delivery room aiming to reduce damage especially to the lungs in the so-called first golden minutes. Herewith, we describe and update four of the most relevant interventions performed in the delivery room: delayed cord clamping, non-invasive ventilation, individualized oxygen supplementation, and maintaining an adequate body temperature so as to avoid hyperthermia and/or hypothermia.

Metabolic adaptation and neuroprotection differ in the retina and choroid in a piglet model of acute postnatal hypoxia

BACKGROUND

Hypoxic-ischemic insults to the neonatal brain may cause neurodevelopmental disorders. Vulnerability of different areas of the neural tissue to hypoxic-ischemic stress might be explained by either heterogeneous sensitivity to oxygen or neuroprotective capability. Our understanding of regional heterogeneity is still incomplete in terms of metabolic reconfiguration and/or activation of neuroprotective mechanisms.

METHODS

We studied, by western blotting, reverse-transcriptase PCR, and tandem mass spectrometry, the response of retina and choroid at protein, gene, and metabolic levels during hypoxia in a piglet model of acute postnatal hypoxia.

RESULTS

We evidenced a metabolic shift towards glycolysis in choroid after hypoxia while retina experienced a dramatic energy stress with decreased mitochondrial metabolites. Hypoxia-inducible transcription factor-1α (HIF-1α) was not stabilized in retina during hypoxia, supported by a deficient signaling from v-akt murine thymoma viral oncogene (AKT) and ERK1/2, and unchanged glutathione redox status. In retina, but not in choroid, phosphorylation of p65 (NF-κB) and increased transcription of target genes may have a major role during hypoxic stress.

CONCLUSION

We showed that the retina engages a distinct pattern of signaling and transcriptional events than observed in the choroid. Retina and choroid may reflect regional sensitivity to hypoxia. While prolonged and intense hypoxia may jeopardize retinal cell survival, choroid sets up a different pattern of response, which promotes adaptation to these adverse conditions.

Delivery room management of extremely low birthweight infants shows marked geographical variations in Italy

AIM

To evaluate any geographical variations in practice and adherence to international guidelines for early delivery room management of extremely low birthweight (ELBW) infants in the North, Centre and South of Italy.

METHODS

A questionnaire was sent to all 107 directors of Italian level III centres between April and August 2012.

RESULTS

There was a 92% (n = 98) response rate. A polyethylene bag/wrap was used by 54 centres (55.1%), with the highest rate in Northern Italy (77.5%) and the lowest rate in Southern (37.7%) areas. In Northern regions, one centre (2.5%) said it used oxygen concentrations >40% to initiate positive pressure ventilation in ELBW infants. These proportions were higher in the Central (14.3%) and Southern (16.2%) areas. A T-piece device for positive pressure ventilation was more frequently available in the Northern (95%) units than in those in the Central (66.7%) and Southern (69.4%) regions. A median of 13% (IQR: 5%-30%) of ELBW infants received chest compressions at birth in Italy: 5%, 18% and 22% in Northern, Central and Southern units, respectively.

CONCLUSION

In Italy, delivery room management of ELBW infants showed marked geographical variations. Implementation of national training programmes could increase adherence to the guidelines and reduce such discordance.

Functional impairment of the auditory pathway after perinatal asphyxia and the short-term effect of perinatal propofol anesthesia in lambs

BACKGROUND

Sensorineural hearing loss (SNHL) is a common feature in the postasphyxial syndrome in newborns. Several anesthetic drugs have been proposed to attenuate secondary neuronal injury elicited by hypoxia-ischemia. We hypothesized that propofol anesthesia reduces auditory impairment after perinatal asphyxia in comparison with isoflurane.

METHODS

Twenty-three pregnant ewes were randomized to propofol or isoflurane anesthesia and sedation. The lambs underwent in utero umbilical cord occlusion (isoflurane n = 5; propofol n = 7) and were compared with sham-treated animals (isoflurane n = 5; propofol n = 6) at a gestational age of 133 d. For 8 h after delivery by cesarean section, repeated auditory brainstem responses (ABRs) were recorded to obtain hearing thresholds, peak amplitudes, latencies, and interpeak latencies.

RESULTS

Significantly elevated mean thresholds, diminished amplitudes, and elevated latencies were observed in the asphyxia group relative to the control group through the observation period. Comparison of anesthetic treatment in the asphyxia group revealed a significantly lower elevation in threshold and less impairment in the ABR amplitudes and latencies during propofol anesthesia as compared with isoflurane anesthesia.

CONCLUSION

Our results support the hypothesis that anesthesia with propofol has a preventive effect on the functional changes to the auditory pathway in the event of perinatal asphyxia.

Metabolomic Analysis of the Effect of Postnatal Hypoxia on the Retina in a Newly Born Piglet Model

The availability of reliable biomarkers of brain injury secondary to birth asphyxia could substantially improve clinical grading, therapeutic intervention strategies, and prognosis. In this study, changes in the metabolome of retinal tissue caused by profound hypoxia in an established neonatal piglet model were investigated using an ultra performance liquid chromatography - quadrupole time of flight mass spectrometry (UPLC-QTOFMS) untargeted metabolomic approach, which included Partial Least Squares - Discriminant Analysis (PLSDA) multivariate data analysis. The initial identification of a set of discriminant metabolites from UPLC-QTOFMS data was confirmed by target UPLC-MS/MS and allowed the selection of endogenous CDP-choline as a promising candidate biomarker for hypoxia-derived brain damage assessing intensity of retinal hypoxia. Results from this study will foster further research on CDP-choline changes occurring during resuscitation.

A multi-parameter system for use in neonatal resuscitation research and training

Training staff in the resuscitation of neonates is an essential skill; resuscitation efficacy is difficult to quantify but critical to infant survival. Objective assessments of the efficacy of training methods, resuscitation techniques and devices have used concurrent measurements of air flow and air pressure in commercially available manikins. This system also simultaneously measures the force transmitted through the manikin head during simulated resuscitation, as applying excessive force may be deleterious to newborn infants. The overall accuracy of the force plate over the range 0-5 kg was 0.5%; the output was linear; the frequency response sufficiently high and there was no evidence of hysteresis. This system enables comparison of staff groups, resuscitation techniques and devices in an accurate and reproducible manner. Its use could improve training by offering a means of objective performance feedback through a range of parameters. Evaluation of clinical practice may also result in direct patient benefit.

Pulmonary hemodynamics and vascular reactivity in asphyxiated term lambs resuscitated with 21 and 100% oxygen

An increase in oxygen tension is an important factor in decreasing pulmonary vascular resistance (PVR) at birth. Birth asphyxia results in acidosis and increased PVR. We determined the effect of resuscitation with 21 vs. 100% O(2) on pulmonary hemodynamics, pulmonary arterial (PA) reactivity, and oxidant stress in a lamb model of in utero asphyxia. Term fetal lambs were acutely asphyxiated by intrauterine umbilical cord occlusion for 10 min resulting in acidosis (pH 6.96 ± 0.05 and Pco(2) 103 ± 5 Torr), bradycardia, systemic hypotension, and increased PVR. Lambs were treated with 30 min of resuscitation with 21% or 100% O(2) (n = 6 each). Pa(O(2)) was significantly elevated with 100% O(2) resuscitation compared with 21% O(2) (430 ± 38 vs. 64 ± 8 Torr), but changes in pH and Pa(CO(2)) were similar. The 100% O(2) induced greater increase in pulmonary blood flow and decrease in PVR at 1 min of life, but subsequent values were similar to 21% O(2) group between 2 and 30 min of life. Oxygen uptake from the lung and systemic oxygen extraction was similar between the two groups. Pulmonary arteries showed increased staining for superoxide anions and increased contractility to norepinephrine following resuscitation with 100% O(2). The increased PA contractility induced by 100% O(2) was reversed by scavenging superoxide anions with superoxide dismutase and catalase. We conclude that resuscitation of asphyxiated lambs with 100% O(2) increases Pa(O(2)) but does not improve lung oxygen uptake, decrease PVR at 30 min, or increase systemic oxygen extraction ratios. Furthermore, 100% O(2) also induces oxidative stress and increases PA contractility. These findings support the new neonatal resuscitation guidelines recommending 21% O(2) for initial resuscitation of asphyxiated neonates.

Recent advances in pediatric anesthesia

Writing about advances in a field of medicine normally includes some pride about progress which one was witness to or even a participant in. The younger one is, the more enthusiastically every advance is lauded and welcomed. This is human nature and nothing to be complained about. However, when anesthesiologists, having worked and struggled in the field of pediatric anesthesia for about 40 years, look back to past advances, a more realistic, even painful picture comes to mind. There was a price which a considerable number of patients had to pay for progress, ruined health or even death. This experience of decades of practice is rarely presented in the literature but should not be forgotten when we proudly remember advances in pediatric anesthesia.

Short- and long-term behavioral effects of exposure to 21%, 40% and 100% oxygen after perinatal hypoxia-ischemia in the rat

Until recently, supplementation with 100% oxygen was standard therapy for newborns who required resuscitation at birth or suffered later hypoxic-ischemic events. Exposure to high concentrations of oxygen, however, may worsen oxidative stress induced by ischemic injury. In this study we investigated the short- and long-term behavioral outcomes in rats that had undergone hypoxic-ischemic brain injury on postnatal day 7, followed by 2h exposure to 21%, 40%, or 100% oxygen, compared to normal controls. There were no differences in the development of walking, head lifting and righting reflexes from postnatal days 9 to 15. Cliff avoidance showed some abnormal responses in the H21 animals. From postnatal days 28 to 56, three tests of sensorimotor coordination were performed weekly: ledged tapered beam, cylinder, and bilateral tactile stimulation. The ledged tapered beam test without prior training of animals was sensitive to injury, but did not distinguish between treatment groups. The cylinder test showed a greater use of the unimpaired limb in female 21% and 40% oxygen groups compared to controls. Performance in both cylinder and the beam tests showed a correlation with the degree of brain injury. The bilateral tactile stimulation test showed that the male 21% oxygen groups had worse sensory asymmetry than male 40% or 100% oxygen groups, but was not statistically significantly different from controls. We thus found a minor benefit to post-hypoxia-ischemic treatment with 100% and 40% oxygen compared to 21% in one test of early motor skills. Our results for long-term sensorimotor behavior, however, showed conflicting results, however, as males treated with 40% or 100% oxygen had less sensory asymmetry (better performance) in the bilateral tactile stimulation test than males treated with 21% oxygen, while females had impaired motor performance in the cylinder test with both 21% and 40% oxygen.