Both extremes of arterial carbon dioxide pressure and the magnitude of fluctuations in arterial carbon dioxide pressure are associated with severe intraventricular hemorrhage in preterm infants

Capnography waveforms: basic interpretation in neonatal intensive care

End-tidal capnography can provide useful clinical information displayed on the ventilator screen or bedside monitor. It is important that clinicians can assess and utilise this information to assist in identifying underlying complications and pulmonary pathology. Sudden change or loss of the CO2 waveform can act as a safety measure in alerting clinicians of a dislodged or blocked endotracheal tube, considering the concurrent flow and volume waveforms. Visual pattern recognition by the clinicians of commonly seen waveform traces may act as an adjunct to other modes of ventilatory monitoring techniques. Waveforms traces can aid clinical management, help identify cases of ventilation asynchrony between the infant and the ventilator. We present some common clinical scenarios where tidal capnography can be useful in the timely identification of pulmonary complication and for practical troubleshooting at the cot-side.

Neuroprotective therapies in the NICU in preterm infants: present and future (Neonatal Neurocritical Care Series)

The survival of preterm infants has steadily improved thanks to advances in perinatal and neonatal intensive clinical care. The focus is now on finding ways to improve morbidities, especially neurological outcomes. Although antenatal steroids and magnesium for preterm infants have become routine therapies, studies have mainly demonstrated short-term benefits for antenatal steroid therapy but limited evidence for impact on long-term neurodevelopmental outcomes. Further advances in neuroprotective and neurorestorative therapies, improved neuromonitoring modalities to optimize recruitment in trials, and improved biomarkers to assess the response to treatment are essential. Among the most promising agents, multipotential stem cells, immunomodulation, and anti-inflammatory therapies can improve neural outcomes in preclinical studies and are the subject of considerable ongoing research. In the meantime, bundles of care protecting and nurturing the brain in the neonatal intensive care unit and beyond should be widely implemented in an effort to limit injury and promote neuroplasticity. IMPACT: With improved survival of preterm infants due to improved antenatal and neonatal care, our focus must now be to improve long-term neurological and neurodevelopmental outcomes. This review details the multifactorial pathogenesis of preterm brain injury and neuroprotective strategies in use at present, including antenatal care, seizure management and non-pharmacological NICU care. We discuss treatment strategies that are being evaluated as potential interventions to improve the neurodevelopmental outcomes of infants born prematurely.

Understanding improved neonatal ventilation trends in a regional transport service

AIM

Review changes in neonatal ventilation practice within our regional transport service, Embrace, identifying interventions with greatest impact on improved rates of normocapnia during transfer.

METHODS

Using internal transport databases and UK Neonatal Transport Group data submissions, we tracked local and national rates of ventilation and normocapnia. We correlated this with internal changes in practice, including introduction of new equipment, staffing changes, educational interventions and quality improvement projects.

RESULTS

Data demonstrated improvement in normocapnia rates benchmarked against national figures, which was not explained by changes in ventilation methods or rates, or by changes in availability of post-transfer gases. Greatest improvement was identified following introduction of transcutaneous CO2 monitoring and ventilators enabling volume-guided ventilation strategies. Additionally, although less quantifiable, educational and quality improvement interventions, and case review mechanisms were felt to be influential.

CONCLUSION

Volume guided ventilation and transcutaneous CO2 monitoring have had a positive influence on the maintenance of normocapnia during transfer at Embrace Transport Service, although introduction of new equipment still presents challenges which must be overcome. Recognising the significant impact of these technologies allows for ongoing financial, time and educational investment to emphasise their importance and ensure appropriate awareness of limitations and troubleshooting options, maximising their positive impact.

Hypercapnia Causes Injury of the Cerebral Cortex and Cognitive Deficits in Newborn Piglets

In critically ill newborns, exposure to hypercapnia (HC) is common and often accepted in neonatal intensive care units to prevent severe lung injury. However, as a "safe" range of arterial partial pressure of carbon dioxide levels in neonates has not been established, the potential impact of HC on the neurodevelopmental outcomes in these newborns remains a matter of concern. Here, in a newborn Yorkshire piglet model of either sex, we show that acute exposure to HC induced persistent cortical neuronal injury, associated cognitive and learning deficits, and long-term suppression of cortical electroencephalogram frequencies. HC induced a transient energy failure in cortical neurons, a persistent dysregulation of calcium-dependent proapoptotic signaling in the cerebral cortex, and activation of the apoptotic cascade, leading to nuclear deoxyribonucleic acid fragmentation. While neither 1 h of HC nor the rapid normalization of HC was associated with changes in cortical bioenergetics, rapid resuscitation resulted in a delayed onset of synaptosomal membrane lipid peroxidation, suggesting a dissociation between energy failure and the occurrence of synaptosomal lipid peroxidation. Even short durations of HC triggered biochemical responses at the subcellular level of the cortical neurons resulting in altered cortical activity and impaired neurobehavior. The deleterious effects of HC on the developing brain should be carefully considered as crucial elements of clinical decisions in the neonatal intensive care unit.

Tracking national neonatal transport activity and metrics using the UK Neonatal Transport Group dataset 2012-2021: a narrative review

There are no internationally agreed descriptors for categories of neonatal transports which facilitate comparisons between settings. To continually review and enhance neonatal transport care we need robust categories to develop benchmarks. This review aimed to report on the development and application of key measures across a national neonatal transport service. The UK Neonatal Transport Group (UK-NTG) developed a core dataset and benchmarks for transported infants and collected annual national data. Data were reported back to teams to allow benchmarking and improvements. From 2012 to 2021, the rate of UK neonatal transfers increased from 18 to 22/1000 live births despite a falling birth rate. Neonatal transfers on nitric oxide increased until 2016 before plateauing. The proportion of transport services able to provide high frequency oscillation and servo-controlled therapeutic hypothermia increased over the study period. High-flow nasal cannula oxygen use increased, becoming the most frequently used non-invasive respiratory support mode. For infants <27 weeks of gestational age, transfers for uplift of care in the first 3 days of life have fallen from 420 (2016) to 288 (2020/2021) and for lack of neonatal capacity from 24 (2016) to 2 (2020/2021). The rate of ventilated infants completing transfer with CO2 out of the benchmark range varied from 9% to 13% with marked variation between transport services' rates of hypocapnia (0-10%) and hypercapnia with acidosis (0-9%). The development of the UK-NTG dataset supports national tracking of activity and clinical trends allowing comparison of patient-focused benchmarks across teams.

Transcutaneous CO2 Monitoring in Extremely Low Birth Weight Premature Infants

Extremely low birth weight (ELBW) premature infants are particularly susceptible to hypocarbia and hypercarbia, which are associated with brain and lung morbidities. Transcutaneous CO2 (TcCO2) monitoring allows for continuous non-invasive CO2 monitoring during invasive and non-invasive ventilation and is becoming more popular in the NICU. We aimed to evaluate the correlation and agreement between CO2 levels measured by a TcCO2 monitor and blood gas CO2 (bgCO2) among ELBW infants. This was a prospective observational multicenter study. All infants < 1000 g admitted to the participating NICUs during the study period were monitored by a TcCO2 monitor, if available. For each bgCO2 measured, a simultaneous TcCO2 measurement was documented. In total, 1828 pairs of TcCO2-bgCO2 values of 94 infants were collected, with a median (IQR) gestational age of 26.4 (26.0, 28.3) weeks and birth weight of 800 (702, 900) g. A moderate correlation (Pearson: r = 0.64) and good agreement (bias (95% limits of agreement)):(2.9 [-11.8, 17.6] mmHg) were found between the TcCO2 and bgCO2 values in the 25-70 mmHg TcCO2 range. The correlation between the TcCO2 and bgCO2 trends was moderate. CO2 measurements by TcCO2 are in good agreement (bias < 5 mmHg) with bgCO2 among premature infants < 1000 g during the first week of life, regardless of day of life, ventilation mode (invasive/non-invasive), and sampling method (arterial/capillary/venous). However, wide limits of agreement and moderate correlation dictate the use of TcCO2 as a complementary tool to blood gas sampling, to assess CO2 levels and trends in individual patients.

Late permissive hypercapnia and respiratory stability among very preterm infants: a pilot randomised trial

OBJECTIVE

Determine if targeting higher transcutaneous carbon dioxide improves respiratory stability among very preterm infants on ventilatory support.

DESIGN

Single-centre pilot randomised clinical trial.

SETTING

The University of Alabama at Birmingham.

PATIENTS

Very preterm infants on ventilatory support after postnatal day 7.

INTERVENTIONS

Infants were randomised to two different transcutaneous carbon dioxide levels targeting 5 mm Hg (0.67 kPa) changes with four sessions each lasting 24 hours for 96 hours: baseline-increase-baseline-increase or baseline-decrease-baseline-decrease.

MAIN OUTCOME MEASURES

We collected cardiorespiratory data evaluating episodes of intermittent hypoxaemia (oxygen saturations (SpO2)<85% for ≥10 s), bradycardia (<100 bpm for ≥10 s), and cerebral and abdominal hypoxaemia on near-infrared spectroscopy.

RESULTS

We enrolled 25 infants with a gestational age of 24 w 6 d±11 d (mean±SD) and birth weight 645±142 g on postnatal day 14±3. Continuous transcutaneous carbon dioxide values (56.8±6.9 in the higher group vs 54.5±7.8 in the lower group; p=0.36) did not differ significantly between groups during the intervention days. There were no differences in intermittent hypoxaemia (126±64 vs 105±61 per 24 hours; p=0.30) or bradycardia (11±16 vs 15±23 per hour; p=0.89) episodes between groups. The proportion of time with SpO2<85%, SpO2<80%, cerebral hypoxaemia or abdominal hypoxaemia did not differ (all p>0.05). There was moderate negative correlation between mean transcutaneous carbon dioxide and bradycardia episodes (r=-0.56; p<0.001).

CONCLUSION

Targeting 5 mm Hg (0.67 kPa) changes in transcutaneous carbon dioxide did not improve respiratory stability among very preterm infants on ventilatory support but the intended carbon dioxide separation was difficult to achieve and maintain.

TRIAL REGISTRATION NUMBER

NCT03333161.

Perioperative anesthetic management of premature neonates weighing less than 1500 grams undergoing transcatheter PDA (TC-PDA) closure: An institutional anesthetic experience

Objectives

The aim of our study is to describe the various anesthetic techniques and intraoperative management used during transcatheter closure of hemodynamically significant PDAs in VLBW premature infants weighing less than 1.5 kg and their potential impact on postoperative outcomes using a retrospective chart review.

Design

A retrospective electronic medical chart review was performed in infants who underwent Transcatheter Patent Ductus Arteriosus (TC-PDA) closure at an academic institution between January 1, 2008 and October 4th 2019. Only premature patients with isolated PDA weighing less than 1500 g at the time of the procedure were included in the study.

Setting

Single Institutional Hospital.

Participants

Premature patients with isolated PDA weighing less than 1500 g at the time of the procedure.

Interventions

None.

Measurements and main results

Interprocedurally, there was no evidence of device embolization or clinically significant vascular obstruction on follow-up echocardiography, and inotropic or vasoactive infusions were not required. All patients survived and were discharged from the hospital after a mean of 86.4 ± 48.49 days (median 74, range 40-180) following initial admission to the NICU. At 7 post-operative days, freedom from ventilatory support reached 70% in all patients. Incidences of device embolization or clinically significant vascular obstruction were not noted on follow-up echocardiography.

Conclusions

Though our preliminary findings show promising outcomes following TC-PDA closure relative to traditional surgical approaches, further investigations with higher patient volume are needed to validate these promising observations.

Clinical Variables Associated With Grade III and IV Intraventricular Hemorrhage (IVH) in Preterm Infants Weighing Less Than 750 Grams

BACKGROUND

Despite innovative advances in neonatal medicine, intraventricular hemorrhage (IVH) continues to be a significant complication in neonatal intensive care units globally.

OBJECTIVE

The study aimed to discern the variables heightening the risk of severe IVH (Grade III and IV) in extremely premature infants weighing less than 750 grams. We postulated that a descending hematocrit (Hct) trend during the first week of life could serve as a predictive marker for the development of severe IVH in this vulnerable population.

METHODS

This retrospective case-control study encompassed infants weighing less than 750 grams at birth, diagnosed with Grade III and/or IV IVH, and born in a tertiary center from 2009 to 2014. A group of 17 infants with severe IVH was compared with 14 gestational age-matched controls. Acid-base status, glucose, fluid goal, urine output, and nutrient (caloric and protein) intake during the first four days of life were meticulously evaluated. Statistically significant variables from baseline data were further analyzed via univariable and multivariable logistic regression analyses, ensuring control for potential confounding variables.

RESULTS

The univariate logistic regression model delineated odds ratios (ORs) of 0.842 for day 2 average Hct (confidence interval [CI], 0.718-0.987) and 0.16 for urine output on day 3 (CI, 0.024-1.056), with the remaining six variables demonstrating no significant association. In the post-multivariable regression analysis, day 2 Hct was the only significant variable (OR, 0.731; 95% CI, 0.537-0.995; P=0.04). The receiver operating characteristic (ROC) curve analysis portrayed an area under the curve of 71% for the day 2 Hct variable.

CONCLUSION

The study revealed that a dip in Hct on day 2 of life augments the likelihood of Grade III and IV IVH among extremely premature infants with a birth weight of less than 750 grams. This insight amplifies our understanding of risk factors associated with severe IVH development in extremely preterm infants, potentially aiding in refining preventive strategies and optimizing clinical management and treatment of these affected infants.

Respiratory Management of the Preterm Infant: Supporting Evidence-Based Practice at the Bedside

Extremely preterm infants frequently require some form of respiratory assistance to facilitate the cardiopulmonary transition that occurs in the first hours of life. Current resuscitation guidelines identify as a primary determinant of overall newborn survival the establishment, immediately after birth, of adequate lung inflation and ventilation to ensure an adequate functional residual capacity. Any respiratory support provided, however, is an important contributing factor to the development of bronchopulmonary dysplasia. The risks correlated to invasive ventilatory techniques increase inversely with gestational age. Preterm infants are born at an early stage of lung development and are more susceptible to lung injury deriving from mechanical ventilation. Any approach aiming to reduce the global burden of preterm lung disease must implement lung-protective ventilation strategies that begin from the newborn’s first breaths in the delivery room. Neonatologists today must be able to manage both invasive and noninvasive forms of respiratory assistance to treat a spectrum of lung diseases ranging from acute to chronic conditions. We searched PubMed for articles on preterm infant respiratory assistance. Our narrative review provides an evidence-based overview on the respiratory management of preterm infants, especially in the acute phase of neonatal respiratory distress syndrome, starting from the delivery room and continuing in the neonatal intensive care unit, including a section regarding exogenous surfactant therapy.

Neuroprotection care bundle implementation is associated with improved long-term neurodevelopmental outcomes in extremely premature infants

OBJECTIVE

To study the impact of an evidence-based neuroprotection care (NPC) bundle on long-term neurodevelopmental impairment (NDI) in infants born extremely premature.

STUDY DESIGN

An NPC bundle targeting predefined risk factors for acute brain injury in extremely preterm infants was implemented. We compared the incidence of composite outcome of death or severe neurodevelopmental impairment (sNDI) at 21 months adjusted age pre and post bundle implementation.

RESULTS

Adjusting for confounding factors, NPC bundle implementation associated with a significant reduction in death or sNDI (aOR, 0.34; 95% CI 0.17-0.68; P = 0.002), mortality (aOR, 0.31; 95% CI (0.12-0.79); P = 0.015), sNDI (aOR, 0.37; 95% CI: 0.12-0.94; P = 0.039), any motor, language, or cognitive composite score &lt;70 (aOR, 0.48; 95% CI: 0.26-0.90; P = 0.021).

CONCLUSION

Implementation of NPC bundle targeting predefined risk factors is associated with a reduction in mortality or sNDI in extremely preterm infants.

Differential regional cerebrovascular reactivity to end-tidal gas combinations commonly seen during anaesthesia: A blood oxygenation level-dependent MRI observational study in awake adult subjects

BACKGROUND

Regional cerebrovascular reactivity (rCVR) is highly variable in the human brain as measured by blood oxygenation level-dependent (BOLD) MRI to changes in both end-tidal CO 2 and O 2 .

OBJECTIVES

We examined awake participants under carefully controlled end-tidal gas concentrations to assess how regional CVR changes may present with end-tidal gas changes seen commonly with anaesthesia.

DESIGN

Observational study.

SETTING

Tertiary care centre, Winnipeg, Canada. The imaging for the study occurred in 2019.

SUBJECTS

Twelve healthy adult subjects.

INTERVENTIONS

Cerebral BOLD response was studied under two end-tidal gas paradigms. First end-tidal oxygen (ETO 2 ) maintained stable whereas ETCO 2 increased incrementally from hypocapnia to hypercapnia (CO 2 ramp); second ETCO 2 maintained stable whereas ETO 2 increased from normoxia to hyperoxia (O 2 ramp). BOLD images were modeled with end-tidal gas sequences split into two equal segments to examine regional CVR.

MAIN OUTCOME MEASURES

The voxel distribution comparing hypocapnia to mild hypercapnia and mild hyperoxia (mean F I O 2  = 0.3) to marked hyperoxia (mean F I O 2  = 0.7) were compared in a paired fashion ( P  < 0.005 to reach threshold for voxel display). Additionally, type analysis was conducted on CO 2 ramp data. This stratifies the BOLD response to the CO 2 ramp into four categories of CVR slope based on segmentation (type A; +/+slope: normal response, type B +/-, type C -/-: intracranial steal, type D -/+.) Types B to D represent altered responses to the CO 2 stimulus.

RESULTS

Differential regional responsiveness was seen for both end-tidal gases. Hypocapnic regional CVR was more marked than hypercapnic CVR in 0.3% of voxels examined ( P  < 0.005, paired comparison); the converse occurred in 2.3% of voxels. For O 2 , mild hyperoxia had more marked CVR in 0.2% of voxels compared with greater hyperoxia; the converse occurred in 0.5% of voxels. All subjects had altered regional CO 2 response based on Type Analysis ranging from 4 ± 2 to 7 ± 3% of voxels.

CONCLUSION

In awake subjects, regional differences and abnormalities in CVR were observed with changes in end-tidal gases common during the conduct of anaesthesia. On the basis of these findings, consideration could be given to minimising regional CVR fluctuations in patients-at-risk of neurological complications by tighter control of end-tidal gases near the individual's resting values.

Periventricular- intraventricular hemorrhage in the premature infant- A historical perspective

The objective of this chapter is to trace the evolution of intraventricular hemorrhage in the premature infant highlighting the importance of the germinal matrix, a critical role for cerebral blood flow changes in the genesis of hemorrhage, clinical factors that increase the bleeding risk, and potential preventative strategies. In 1976, neuropathological studies demonstrated capillary rupture within the germinal matrix as the precursor of hemorrhage. In 1980, introduction of cranial ultrasound facilitated diagnosis of intraventricular hemorrhage. In 1979, loss of cerebral autoregulation in sick newborn infants was demonstrated. In the 1980's, studies demonstrated the importance of intravascular factors in provoking hemorrhage. In 1983, the association of cerebral blood flow velocity fluctuations and subsequent hemorrhage was demonstrated. In 1994, antenatal steroids use to accelerate lung development was recommended. This was associated with an unanticipated reduction in hemorrhage. In the mid 1990's early indomethacin administration was associated with a reduction of severe hemorrhage.

Pathogenesis and prevention of intraventricular hemorrhage

Despite improvements in the mortality rates of preterm infants, rates of germinal matrix intraventricular hemorrhage (IVH) have remained static with an overall incidence of 25% in infants less than 32 weeks. The importance of the lesion relates primarily to the underlying injury to the developing brain and the associated long-term neurodevelopmental consequences. This clinical-orientated review focuses on the pathogenesis of IVH and discusses the evidence behind proposed prevention strategies.

Hypercapnia: An Added Culprit in Gray Matter Injury in Preterm Neonates

Over the last decade, there has been increased recognition of diverse forms of primary gray matter injury (GMI) in postpreterm neonates. In this study, we aimed to assess whether early neonatal hypercapnia in the preterm infant was associated with GMI on magnetic resonance imaging (MRI) at term equivalent age (TEA). All blood gases taken during the first 2 weeks of life were analyzed for hypercapnia. MRI was performed at TEA postpreterm infants using a unique neonatal MRI 1T scanner. The neonatal MRI scans were assessed using a standardized scoring system, the Kidokoro scoring system, a method used to assess abnormal brain metrics and the presence and severity of brain abnormalities. Subscores are assigned for different regions of the brain. Twenty-nine infants were studied, about half of whom had evidence of some gray matter abnormality. Fifteen of the infants were hypercapnic. The hypercapnic infants had significantly higher deep gray matter abnormality readings as compared with the nonhypercapnic infants (12 [11; 12] vs. 10 [8; 11], respectively; p = 0.0106). Correlations were observed between peak pCO₂ over the first 2 weeks of life and the overall gray matter abnormality score (GMAS) at TEA, and between the percentage of hypercapnic blood gases during the first 2 weeks of life and the GMAS. All of the infants in our population who had severe GMI at TEA were hypercapnic in the first 2 weeks of life. In conclusion, our data show a correlation between early hypercapnia in preterm neonates and GMI at TEA.

Closed-Loop Control of Arterial CO2 in Mechanical Ventilation of Neonates

During mechanical ventilation of the neonate the main goal is to stabilize respiratory function of the often premature lungs. Ventilating the patient without inflicting harm is then the subordinated next goal. Ideally the arterial partial pressure of CO₂ lays within a normocapnic range and fluctuations are kept minimal. By closely monitoring CO₂ and controlling ventilation parameters accordingly, CO₂ levels in the blood can be managed. We present an approach consisting of a cascaded controller for arterial CO₂ by approximating arterial partial pressure PaCO₂ from end-tidal PetCO₂. As a proof of concept, feasibility of the controller was first evaluated on a mathematical patient model and subsequently in-vivo in lamb experiments. The controller is able to regulate CO₂ into a normocapnic range in both setups with satisfactory stationarity within the target range. Estimation of the arterial partial pressure of CO₂ remains a critical aspect that needs to be further investigated. Clinical relevance-Closed-loop control of CO2 in mechanical ventilation aims to avoid PaC O2 extremes and to reduce fluctuations. Both are a relevant risk factors especially for neurological complications among preterm newborns.

Study of the relationship between regional cerebral saturation and pCO2 changes during mechanical ventilation to evaluate modifications in cerebral perfusion in a newborn piglet model

Near-infrared spectroscopy (NIRS) could be a useful continuous, non-invasive technique for monitoring the effect of partial pressure of carbon dioxide (PaCO₂) fluctuations in the cerebral circulation during ventilation. The aim of this study was to examine the efficacy of NIRS to detect acute changes in cerebral blood flow following PaCO₂ fluctuations after confirming the autoregulation physiology in piglets. Fourteen piglets (<72 h of life) were studied. Mean arterial blood pressure, oxygen saturation, pH, glycemia, hemoglobin, electrolytes, and temperature were monitored. Eight animals were used to evaluate brain autoregulation, assessing superior cava vein Doppler as a proxy of cerebral blood flow changing mean arterial blood pressure. Another 6 animals were used to assess hypercapnia generated by decreasing ventilatory settings and complementary CO₂ through the ventilator circuit and hypocapnia due to increasing ventilatory settings. Cerebral blood flow was determined by jugular vein blood flow by Doppler and continuously monitored with NIRS. A decrease in PaCO₂ was observed after hyperventilation (47.6±2.4 to 29.0±4.9 mmHg). An increase in PaCO₂ was observed after hypoventilation (48.5±5.5 to 90.4±25.1 mmHg). A decrease in cerebral blood flow after hyperventilation (21.8±10.4 to 15.1±11.0 mL/min) and an increase after hypoventilation (23.4±8.4 to 38.3±10.5 mL/min) were detected by Doppler ultrasound. A significant correlation was found between cerebral oxygenation and Doppler-derived parameters of blood flow and PaCO₂. Although cerebral NIRS monitoring is mainly used to detect changes in regional brain oxygenation, modifications in cerebral blood flow following experimental PaCO₂ changes were detected in newborn piglets when no other important variables were modified.

A Quality Improvement Bundle to Improve Outcomes in Extremely Preterm Infants in the First Week

OBJECTIVES

Our objective with this quality improvement initiative was to reduce rates of severe intracranial hemorrhage (ICH) or death in the first week after birth among extremely preterm infants.

METHODS

The quality improvement initiative was conducted from April 2014 to September 2020 at the University of Alabama at Birmingham's NICU. All actively treated inborn extremely preterm infants without congenital anomalies from 22 + 0/7 to 27 + 6/7 weeks' gestation with a birth weight ≥400 g were included. The primary outcome was severe ICH or death in the first 7 days after birth. Balancing measures included rates of acute kidney injury and spontaneous intestinal perforation. Outcome and process measure data were analyzed by using p-charts.

RESULTS

We studied 820 infants with a mean gestational age of 25 + 3/7 weeks and median birth weight of 744 g. The rate of severe ICH or death in the first week after birth decreased from the baseline rate of 27.4% to 15.0%. The rate of severe ICH decreased from a baseline rate of 16.4% to 10.0%. Special cause variation in the rate of severe ICH or death in the first week after birth was observed corresponding with improvement in carbon dioxide and pH targeting, compliance with delayed cord clamping, and expanded use of indomethacin prophylaxis.

CONCLUSIONS

Implementation of a bundle of evidence-based potentially better practices by using specific electronic order sets was associated with a lower rate of severe ICH or death in the first week among extremely preterm infants.

Modes of ventilation for pediatric patients under anesthesia: A Pro/Con conversation

The development of sophisticated modes of ventilation for pediatric patients undergoing anesthesia is ongoing; what remains a challenge for the pediatric anesthesiologist is thoughtful selection of the mode(s) of ventilation for a particular patient in the context of the surgical procedure and the goals of the anesthetic. This article provides some historical accounting of a variety of modes of ventilation, defines the terminology of modern ventilatory modes, and reviews in detail the benefits and pitfalls of the specific modes of ventilation and their applicability to the practice of pediatric anesthesiology. In an attempt to debate the Pros and Cons of different modes of ventilation, and to finally resolve the debate "spontaneous vs. controlled ventilation," we share with you a thoughtful conversation of the continuum of modes of ventilation and their applicability to our pediatric anesthesia population.

Carbon dioxide levels in neonates: what are safe parameters?

There is no consensus on the optimal pCO₂ levels in the newborn. We reviewed the effects of hypercapnia and hypocapnia and existing carbon dioxide thresholds in neonates. A systematic review was conducted in accordance with the PRISMA statement and MOOSE guidelines. Two hundred and ninety-nine studies were screened and 37 studies included. Covidence online software was employed to streamline relevant articles. Hypocapnia was associated with predominantly neurological side effects while hypercapnia was linked with neurological, respiratory and gastrointestinal outcomes and Retinpathy of prematurity (ROP). Permissive hypercapnia did not decrease periventricular leukomalacia (PVL), ROP, hydrocephalus or air leaks. As safe pCO₂ ranges were not explicitly concluded in the studies chosen, it was indirectly extrapolated with reference to pCO₂ levels that were found to increase the risk of neonatal disease. Although PaCO₂ ranges were reported from 2.6 to 8.7 kPa (19.5-64.3 mmHg) in both term and preterm infants, there are little data on the safety of these ranges. For permissive hypercapnia, parameters described for bronchopulmonary dysplasia (BPD; PaCO₂ 6.0-7.3 kPa: 45.0-54.8 mmHg) and congenital diaphragmatic hernia (CDH; PaCO₂ ≤ 8.7 kPa: ≤65.3 mmHg) were identified. Contradictory findings on the effectiveness of permissive hypercapnia highlight the need for further data on appropriate CO₂ parameters and correlation with outcomes. IMPACT: There is no consensus on the optimal pCO₂ levels in the newborn. There is no consensus on the effectiveness of permissive hypercapnia in neonates. A safe range of pCO₂ of 5-7 kPa was inferred following systematic review.

Feasibility of portable capnometer for mechanically ventilated preterm infants in the delivery room

This study aimed to determine whether a specific portable capnometer (EMMA™) can facilitate the maintenance of an appropriate partial pressure of arterial carbon dioxide (PaCO₂) in intubated preterm infants in the delivery room. This study included preterm infants with a gestational age of 26 + 0 to 31 + 6 weeks who required intubation in the delivery room. We prospectively identified 40 infants who underwent the EMMA™ monitoring intervention group and 43 infants who did not undergo monitoring (historical control group). PaCO₂ was evaluated either at admission in the neonatal intensive care unit or at 2 h after birth. The proportion of infants with an appropriate PaCO₂ (35-60 mmHg) was greater in the intervention group than in the control group (80% vs. 42%; p = 0.001). There were no significant differences in the rate of accidental extubation (5.0% vs. 7.0%, p = 1.00) or in the proportion of infants with an appropriate PaCO₂ among infants whose birth weight was < 1000 g (54% vs. 40%, p = 0.49). However, among infants whose birth weight was ≥ 1000 g, the PaCO₂ tended to be more appropriate in the intervention group than in the control group (93% vs. 44%; p < 0.001).Conclusion: The EMMA™ facilitated the maintenance of an appropriate PaCO₂ for mechanically ventilated preterm infants, especially infants with birth weight ≥1000 g, in the delivery room. What is Known: • An inappropriate partial pressure of arterial carbon dioxide has been associated with intraventricular hemorrhage in preterm infants. • There is a need to appropriately control the partial pressure of arterial carbon dioxide in preterm infants. What is New: • This is the first report regarding the feasibility of a portable capnometer, the EMMA™, in the delivery room. • The EMMA™ may be considered a feasible monitoring device in the delivery room for intubated preterm infants, especially infants with birth weight ≥1000 g.

Impact of a “Brain Protection Bundle” in Reducing Severe Intraventricular Hemorrhage in Preterm Infants <30 Weeks GA: A Retrospective Single Centre Study

Background: despite advances in perinatal care, periventricular/intraventricular hemorrhage (IVH) continues to remain high in neonatal intensive care units (NICUs) worldwide. Studies have demonstrated the benefits of implementing interventions during the antenatal period, stabilization after birth (golden hour management) and postnatally in the first 72 h to reduce the incidence of IVH. Objective: to compare the incidence of severe intraventricular hemorrhage (IVH ≥ Grade III) before and after implementation of a “brain protection bundle” in preterm infants <30 weeks GA. Study design: a pre- and post-implementation retrospective cohort study to compare the incidence of severe IVH following execution of a “brain protection bundle for the first 72 h from 2015 to 2018. Demographics, management practices at birth and in the NICU, cranial ultrasound results and short-term morbidities were compared. Results: a total of 189 and 215 infants were included in the pre- and post-implementation phase, respectively. No difference in the incidence of severe IVH (6.9% vs. 9.8%, p = 0.37) was observed on the first cranial scan performed after 72 h of age. Conclusion: the implementation of a “brain protection bundle” was not effective in reducing the incidence of severe IVH within the first 72 h of life in our centre.

Carbon dioxide monitoring in the newborn infant

Carbon dioxide (CO₂ ) monitoring is vital during mechanical ventilation of newborn infants, as morbidity increases when CO₂ levels are inappropriate. Our aim was to review the uses and limitations of such noninvasive monitoring methods. Colorimetry is primarily utilized during resuscitation to determine whether successful intubation has occurred. False negative and positive results can however lead to delays in detecting tracheal versus esophageal intubation. Transcutaneous carbon dioxide sensors have limited use during resuscitation, but can be utilized to provide continuous trend data during on-going ventilation. End-tidal capnography can provide clinicians with quantitative end-tidal CO₂ (EtCO₂ ) values and a continuous real-time capnogram waveform trace. These devices are becoming more widely accepted for use in the neonatal population as the new devices are lightweight with minimal additional dead space. Nevertheless, they have been reported to have variable accuracy when compared to arterial CO₂ measurements, however, divergence of results may be related to disease severity rather than technological limitations. During resuscitation EtCO₂ can be detected by capnography more rapidly than by colorimetry. Furthermore, capnography can be currently utilized in neonatal research settings to determine the physiological dead space and ventilation inhomogeneity, and thus has potential to be beneficial to clinical care. In conclusion, novel modes of noninvasive carbon dioxide monitoring can be safely and reliably utilized in newborn infants during mechanical ventilation. Future randomized trials should aim to address which device provides the most optimal form of monitoring in different clinical contexts.

Effect of electrode temperature on measurements of transcutaneous carbon dioxide partial pressure and oxygen partial pressure in very low birth weight infants

OBJECTIVES

To evaluate the accuracy and safety of measurements of transcutaneous carbon dioxide partial pressure (TcPCO₂) and transcutaneous oxygen partial pressure (TcPO₂) at electrode temperatures lower than the value used in clinical practice in very low birth weight infants.

METHODS

A total of 45 very low birth weight infants were enrolled. TcPCO₂ and TcPO₂ measurements were performed in these infants. Two transcutaneous monitors were placed simultaneously for each subject. One electrode was set and maintained at 42℃ used in clinical practice for neonates (control group), and the other was successively set at 38℃, 39℃, 40°C, and 41℃ (experimental group). The paired t-test was used to compare the measurement results between the groups. A Pearson correlation analysis was used to analyze the correlation between the measurement results of the experimental group and control group, and between the measurement results of experimental group and arterial blood gas parameters.

RESULTS

There was no significant difference in TcPCO₂ between each experimental subgroup (38-41℃) and the control group. TcPCO₂ in each experimental subgroup (38-41℃) was strongly positively correlated with TcPCO₂ in the control group (r>0.9, P<0.05) and arterial carbon dioxide partial pressure (r>0.8, P<0.05). There were significant differences in TcPO₂ between each experimental subgroup (38-41℃) and the control group (P<0.05), but TcPO₂ in each experimental subgroup (38-41℃) was positively correlated with TcPO₂ in the control group (r=0.493-0.574, P<0.05) and arterial oxygen partial pressure (r=0.324-0.399, P<0.05). No skin injury occurred during transcutaneous measurements at all electrode temperatures.

CONCLUSIONS

Lower electrode temperatures (38-41℃) can accurately measure blood carbon dioxide partial pressure in very low birth weight infants, and thus can be used to replace the electrode temperature of 42°C. Transcutaneous measurements at the lower electrode temperatures may be helpful for understanding the changing trend of blood oxygen partial pressure.

End-tidal capnography monitoring in infants ventilated on the neonatal intensive care unit

OBJECTIVE

To assess whether end-tidal capnography (EtCO2) monitoring reduced the magnitude of difference in carbon dioxide (CO2) levels and the number of blood gases in ventilated infants.

STUDY DESIGN

A case-control study of a prospective cohort (n = 36) with capnography monitoring and matched historical controls (n = 36).

RESULT

The infants had a median gestational age of 31.6 weeks. A reduction in the highest CO2 level on day 1 after birth was observed after the introduction of EtCO2 monitoring (p = 0.043). There was also a reduction in the magnitude of difference in CO2 levels on days 1 (p = 0.002) and 4 (p = 0.049) after birth. There was no significant difference in the number of blood gases.

CONCLUSION

Continuous end-tidal capnography monitoring in ventilated infants was associated with a reduction in the degree of the magnitude of difference in CO2 levels and highest level of CO2 on the first day after birth.

Transcutaneous carbon dioxide pattern and trend over time in preterm infants

BACKGROUND

Chronic lung disease remains a burden for extremely preterm infants. The changes in ventilation over time and optimal ventilatory management remains unknown. Newer, non-invasive technologies provide insight into these patterns.

METHODS

This single-center prospective cohort study enrolled infants ≤32 0/7 weeks. We obtained epochs of transcutaneous carbon dioxide (TcCO₂) measurements twice each week to describe the pattern of hypercarbia throughout their hospitalization.

RESULTS

Patterns of hypercarbia varied based on birth gestational age and post-menstrual age (PMA) (p = 0.03), regardless of respiratory support. Infants receiving the most respiratory support had values 16-21 mmHg higher than those on room air (p < 0.001). Infants born at the youngest gestational ages had the greatest total change but the rate of change was slower (p = 0.049) compared to infants born at later gestational ages. All infants had TcCO₂ values stabilize by 31-33 weeks PMA, when values were not significantly different compared to discharge. No rebound was observed when infants weaned off invasive support.

CONCLUSIONS

Hypercarbia improves as infants approached 31-33 weeks PMA. Hypercarbia was the highest in the most immature infants and improved with age and growth despite weaning respiratory support.

IMPACT

This study describes the evolution of hypercarbia as very preterm infants grow and develop. The pattern of ventilation is significantly different depending on the gestational age at birth and post-menstrual age. Average transcutaneous carbon dioxide (TCO₂) decreased over time as infants became more mature despite weaning respiratory support. This improvement was most significant in infants born at the lowest gestational ages.

Non-invasive carbon dioxide monitoring in neonates: methods, benefits, and pitfalls

Wide fluctuations in partial pressure of carbon dioxide (PaCO₂) can potentially be associated with neurological and lung injury in neonates. Blood gas measurement is the gold standard for assessing gas exchange but is intermittent, invasive, and contributes to iatrogenic blood loss. Non-invasive carbon dioxide (CO₂) monitoring has become ubiquitous in anesthesia and critical care and is being increasingly used in neonates. Two common methods of non-invasive CO₂ monitoring are end-tidal and transcutaneous. A colorimetric CO₂ detector (a modified end-tidal CO₂ detector) is recommended by the International Liaison Committee on Resuscitation (ILCOR) and the American Academy of Pediatrics to confirm endotracheal tube placement. Continuous CO₂ monitoring is helpful in trending PaCO₂ in critically ill neonates on respiratory support and can potentially lead to early detection and minimization of fluctuations in PaCO₂. This review includes a description of the various types of CO₂ monitoring and their applications, benefits, and limitations in neonates.

Neuroprotection Care Bundle Implementation to Decrease Acute Brain Injury in Preterm Infants

BACKGROUND

We assessed the impact of an evidence-based neuroprotection care bundle on the risk of brain injury in extremely preterm infants.

METHODS

We implemented a neuroprotection care bundle consisting of a combination of neuroprotection interventions such as minimal handling, midline head position, deferred cord clamping, and protocolization of hemodynamic and respiratory managements. These interventions targeted risk factors for acute brain injury in extremely preterm infants (born at gestational age less than 29 weeks) during the first three days of birth. Implementation occurred in a stepwise manner, including care bundle development by a multidisciplinary care team based on previous evidence and experience, standardization of outcome assessment tools, and education. We compared the incidence of the composite outcome of acute preterm brain injury or death preimplementation and postimplementation.

RESULTS

Neuroprotection care bundle implementation associated with a significant reduction in acute brain injury risk factors such as the use of inotropes (24% before, 7% after, P value < 0.001) and fluid boluses (37% before, 19% after, P value < 0.001), pneumothorax (5% before, 2% after, P value = 0.002), and opioid use (19% before, 7% after, P value < 0.001). Adjusting for confounding factors, the neuroprotection care bundle significantly reduced death or severe brain injury (adjusted odds ratio, 0.34; 95% confidence interval, 0.20 to 0.59; P value < 0.001) and severe brain injury (adjusted odds ratio, 0.31; 95% confidence interval, 0.17 to 0.58; P < 0.001).

CONCLUSIONS

Implementation of neuroprotection care bundle targeting predefined risk factors is feasible and effective in reducing acute brain injury in extremely preterm infants.

Is Anesthesia Bad for the Brain? Current Knowledge on the Impact of Anesthetics on the Developing Brain

There are compelling preclinical data that common general anesthetics cause increased neuroapoptosis in juvenile animals. Retrospective studies demonstrate that young children exposed to anesthesia have school difficulties, which could be caused by anesthetic neurotoxicity, perioperative hemodynamic and homeostatic instability, underlying morbidity, or the neuroinflammatory effects of surgical trauma. Unnecessary procedures should be avoided. Baseline measures of blood pressure are important in determining perioperative blood pressure goals. Inadvertent hypocapnia or moderate hypercapnia and hyperoxia or hypoxia should be avoided. Pediatric patients should be maintained in a normothermic, euglycemic state with neutral positioning. Improving outcomes of infants and children requires the collaboration of anesthesiologists, surgeons, pediatricians and neonatologists.

Assessment of sidestream end-tidal capnography in ventilated infants on the neonatal unit

OBJECTIVES

Continuous monitoring of carbon dioxide (CO₂ ) levels can be achieved by capnography. Our aims were to compare the performance of a sidestream capnograph with a low dead space and sampling rate to a mainstream device and evaluate whether its results correlated with arterial/capillary CO₂ levels in infants with different respiratory disease severities.

WORKING HYPOTHESES

End-tidal carbon dioxide (EtCO₂ ) results by sidestream and mainstream capnography would correlate, but the divergence of EtCO₂ and CO₂ results would occur in more severe lung disease.

STUDY DESIGN

Prospective cohort study.

PATIENT-SUBJECT SELECTION

Fifty infants with a median (interquartile range) gestational age of 31.1 (27.1-37.4) weeks and birth weight of 1.37 (0.76-2.95) kg.

METHODOLOGY

Concurrent measurements of EtCO₂ in ventilated infants were made using a new Microstream sidestream device and a mainstream capnograph (gold standard). Results from both devices were compared with arterial or capillary CO₂ levels. The ratio of dead space to tidal volume (Vd/Vt) was calculated to assess respiratory disease severity.

RESULTS

The mean difference between the concurrent measurements of EtCO₂ was -0.54 ± 0.67 kPa (95% agreement levels - 1.86 to 0.77 kPa), the correlation between the two was r = .85 (P < .001). Sidestream capnography results correlated better with partial pressure of CO₂ (PCO₂ ) levels in infants with less (Vd/Vt < 0.35; r²  = .66, P < .001) rather than more severe (Vd/Vt > 0.35; r²  = .33, P = .01) lung disease.

CONCLUSIONS

The sidestream capnography performed similarly to the mainstream capnography. The poorer correlation of EtCO₂ to PCO₂ levels in infants with severe respiratory disease should highlight to clinicians increased ventilation-perfusion mismatch.

Beyond Anesthesia Toxicity: Anesthetic Considerations to Lessen the Risk of Neonatal Neurological Injury

Infants who undergo surgical procedures in the first few months of life are at a higher risk of death or subsequent neurodevelopmental abnormalities. Although the pathogenesis of these outcomes is multifactorial, an understanding of the nature and pathogenesis of brain injury in these infants may assist the anesthesiologist in consideration of their day-to-day practice to minimize such risks. This review will summarize the main types of brain injury in preterm and term infants and their key pathways. In addition, the review will address key potential pathogenic pathways that may be modifiable including intraoperative hypotension, hypocapnia, hyperoxia or hypoxia, hypoglycemia, and hyperthermia. Each of these conditions may increase the risk of perioperative neurological injury, but their long-term ramifications are unclear.

N-BiPAP vs n-CPAP in term neonate with respiratory distress syndrome

BACKGROUND

Non-invasive respiratory ventilation has greatly improved the evolution of respiratory distress in neonates, especially for preterm infants, but few studies have investigated the use of non-invasive ventilation (NIV) in term infants. It is useful for neonatologists and nurses to identify the optimal ventilation strategy in terms of effectiveness for this group of newborns. The aim of our study was to investigate what type of respiratory support between nasal Continuous Positive Airway Pressure (nCPAP) or nasal Biphasic Positive Airway Pressure (nBiPAP) is more effective in term neonates with RDS.

METHODS

Our study was a retrospective observational study of 78 full term neonates who were admitted to the NICU at S. Bambino Hospital from December 2015 to December 2016 for respiratory distress at birth. All patients underwent non-invasive ventilation by nCPAP or nBiPAP were included. Oxygen saturations and vital signs were monitored continuously. We evaluated blood gas analysis parameters before treatment and after 1 h of ventilation.

RESULTS

During the study period, there were 78 full term newborns admitted in our NICU for neonatal distress who were treated with nCPAP ore nBIPAP ventilation. In nBiPAP patients, we noticed a statistically significant reduction in PaCO2 levels and FiO2 requirement with respect to nCPAP patients, after 1 h of ventilation with a simultaneous significant increase of pH and PaO2 levels. There was no difference in the length of NIV and hospital stay. Among nCPAP patients, two were then intubated and one developed a pneumothorax.

CONCLUSION

The results of our study showed that an early BiPAP ventilation on RDS is the more efficient NIV because it improves CO2 removal and reduces FiO2 requirement in comparison to nCPAP. Future studies can clarify if early BiPAP ventilation on RDS is the more efficient of NIV.

End-tidal carbon dioxide levels during resuscitation and carbon dioxide levels in the immediate neonatal period and intraventricular haemorrhage

Abnormal levels of end-tidal carbon dioxide (EtCO₂) during resuscitation in the delivery suite are associated with intraventricular haemorrhage (IVH) development. Our aim was to determine whether carbon dioxide (CO₂) levels in the first 3 days after birth reflected abnormal EtCO₂ levels in the delivery suite, and hence, a prolonged rather than an early insult resulted in IVH. In addition, we determined if greater EtCO₂level fluctuations during resuscitation occurred in infants who developed IVH. EtCO₂ levels during delivery suite resuscitation and CO₂ levels on the neonatal unit were evaluated in 58 infants (median gestational age 27.3 weeks). Delta EtCO₂ was the difference between the highest and lowest level of EtCO₂. Thirteen infants developed a grade 3-4 IVH (severe group). There were no significant differences in CO₂ levels between those who did and did not develop an IVH (or severe IVH) on the NICU. The delta EtCO₂ during resuscitation differed between infants with any IVH (6.2 (5.4-7.5) kPa) or no IVH (3.8 (2.7-4.3) kPA) (p < 0.001) after adjusting for differences in gestational age. Delta EtCO₂ levels gave an area under the ROC curve of 0.940 for prediction of IVH.Conclusion: The results emphasize the importance of monitoring EtCO₂ levels in the delivery suite.What is Known:• Abnormal levels of carbon dioxide (CO₂) in the first few days after birth and abnormal end-tidal CO₂levels (EtCO₂) levels during resuscitation are associated in preterm infants with the risk of developing intraventricular haemorrhage (IVH).What is New:• There were no significant differences in NICU CO₂levels between those who developed an IVH or no IVH.• There was a poor correlation between delivery suite ETCO₂levels and NICU CO₂levels.• Large fluctuations in EtCO₂during resuscitation in the delivery suite were highly predictive of IVH development in preterm infants.

Metabolic acidosis rather than hypo/hypercapnia in the first 72 hours of life associated with intraventricular hemorrhage in preterm neonates

Aim: Safe limits of arterial partial pressure of carbon dioxide (PaCO₂) and acidosis in premature infants are not well defined. Both respiratory and systemic illness along with center-specific ventilation strategies contribute to PaCO₂ fluctuations and acid-base imbalances during the critical time period of first 72 h of life. This study evaluated the association between early blood gas parameters and intraventricular hemorrhage (IVH) in preterm infants.Methods: This retrospective observational study included neonates with a gestational age (GA) of ≤29 wks, who had at least 7 blood gas analysis done within the first 72 h of life. By adjusting for known variables that predispose to IVH, multivariable logistic regression analysis was used to study the association of PaCO₂ and acid-base measures with the risk of IVH.Results: Between 2013-2016, among 272 neonates who met inclusion criteria and were assessed for IVH on cranial ultrasound within first week of life, 101 neonates [mean GA of 25 ± 1.5 wks] had IVH and 171 neonates [mean GA of 25 ± 1.6 wks] had normal scans. After adjustment for confounding variables, higher values of maximum lactate (OR = 1.18, 95% CI = 1.1-1.3, p < .0001) and maximum base deficit (OR = 1.19, 95% CI = 1.1-1.2, p < .0001) within 72 h of life increased the likelihood of any grade of IVH. However, time-weighted average PaCO₂, maximum and minimum PaCO₂ had no statistically significant effect on the risk of IVH. The relationship remained unchanged even when moderate-severe IVH was considered as the primary outcome.Conclusion: Severe metabolic acidosis rather than hypo/hypercapnia during the first 72 h of life was associated with higher odds of IVH in infants born at ≤29 wks of gestation. Future studies determining levels of PaCO₂ that is safe for premature brain would need to control for the metabolic component of acidosis.

Continuous Noninvasive Carbon Dioxide Monitoring in Neonates: From Theory to Standard of Care

Ventilatory support may affect the short- and long-term neurologic and respiratory morbidities of preterm infants. Ongoing monitoring of oxygenation and ventilation and control of adequate levels of oxygen, pressures, and volumes can decrease the incidence of such adverse outcomes. Use of pulse oximetry became a standard of care for titrating oxygen delivery, but continuous noninvasive monitoring of carbon dioxide (CO₂) is not routinely used in NICUs. Continuous monitoring of CO₂ level may be crucial because hypocarbia and hypercarbia in extremely preterm infants are associated with lung and brain morbidities, specifically bronchopulmonary dysplasia, intraventricular hemorrhage, and cystic periventricular leukomalacia. It is shown that continuous monitoring of CO₂ levels helps in maintaining stable CO₂ values within an accepted target range. Continuous monitoring of CO₂ levels can be used in the delivery room, during transport, and in infants receiving invasive or noninvasive respiratory support in the NICU. It is logical to hypothesize that this will result in better outcome for extremely preterm infants. In this article, we review the different noninvasive CO₂ monitoring alternatives and devices, their advantages and disadvantages, and the available clinical data supporting or negating their use as a standard of care in NICUs.

Neuroprotection from acute brain injury in preterm infants

Infants born at ≤32⁺⁶ weeks gestation are at higher risk for intracranial ischemic and hemorrhagic injuries, which often occur in the first 72 hours postbirth. Antenatal strategies to reduce the incidence of acute brain injuries include administering maternal corticosteroids and prompt antibiotic treatment for chorioamnionitis. Perinatal strategies include delivery within a tertiary centre, delayed cord clamping, and preventing hypothermia. Postnatal strategies include empiric treatment with antibiotics when chorioamnionitis is suspected, the cautious use of inotropes, the avoidance of blood PCO2 fluctuation, and neutral head positioning. Clinicians should be aware of the policies and procedures that, especially when combined, can provide neuroprotection for preterm infants.

Beneficial Effects of Remifentanil Against Excitotoxic Brain Damage in Newborn Mice

Background: Remifentanil, a synthetic opioid used for analgesia during cesarean sections, has been shown in ex vivo experiments to exert anti-apoptotic activity on immature mice brains. The present study aimed to characterize the impact of remifentanil on brain lesions using an in vivo model of excitotoxic neonatal brain injury. Methods: Postnatal day 2 (P2) mice received three intraperitoneal injections of remifentanil (500 ng/g over a 10-min period) or saline just before an intracortical injection of ibotenate (10 μg). Cerebral reactive oxygen species (ROS) production, cell death, in situ labeling of cortical caspase activity, astrogliosis, inflammation mediators, and lesion size were determined at various time points after ibotenate injection. Finally, behavioral tests were performed until P18. Results: In the injured neonatal brain, remifentanil significantly decreased ROS production, cortical caspase activity, DNA fragmentation, interleukin-1β levels, and reactive astrogliosis. At P7, the sizes of the ibotenate-induced lesions were significantly reduced by remifentanil treatment. Performance on negative geotaxis (P6-8) and grasping reflex (P10-12) tests was improved in the remifentanil group. At P18, a sex specificity was noticed; remifentanil-treated females spent more time in the open field center than did the controls, suggesting less anxiety in young female mice. Conclusions: In vivo exposure to remifentanil exerts a beneficial effect against excitotoxicity on the developing mouse brain, which is associated with a reduction in the size of ibotenate-induced brain lesion as well as prevention of some behavioral deficits in young mice. The long-term effect of neonatal exposure to remifentanil should be investigated.

Preterm brain injury: Germinal matrix-intraventricular hemorrhage and post-hemorrhagic ventricular dilatation

Germinal matrix hemorrhage and intraventricular hemorrhages (GMH-IVH) remain a common and clinically significant problem in preterm infants, particularly extremely preterm infants. A large GMH-IVH is often complicated by posthemorrhagic ventricular dilation (PHVD) or parenchymal hemorrhagic infarction and is associated with an increased risk of adverse neurologic sequelae. The widespread use of cranial ultrasonography since the early 1980s has shown a gradual decrease in the incidence of GMH-IVH and has helped with the identification of antenatal and perinatal risk factors and timing of the lesion. The increased use of magnetic resonance imaging (MRI) has contributed to more detailed visualization of the site and extent of the GMH-IVH. In addition, MRI has contributed to the awareness of associated white matter changes as well as associated cerebellar hemorrhages. Although GMH-IVH and PHVD still cannot be prevented, cerebrospinal fluid drainage initiated in the early stage of PHVD development seems to be associated with a better neurodevelopmental outcome. Further studies are underway to improve treatment strategies for PHVD and to potentially prevent and repair GMH-IVH and PHVD and associated brain injury. This chapter discusses the pathogenesis, incidence, risk factors, and management, including preventive measures, of GHM-IVH and PHVD.

Successful implementation of an intracranial hemorrhage (ICH) bundle in reducing severe ICH: a quality improvement project

OBJECTIVE

Our specific, measurable, attainable, relevant, and time-limited (SMART) aim was to reduce the incidence of severe intracranial hemorrhage (ICH) among preterm infants born <30 weeks' gestation from a baseline of 24% (January 2012-December 2013) to a long-term average of 11% by December 2015.

STUDY DESIGN

We instituted an ICH bundle consisting of elements of the "golden hour" (delayed cord clamping, optimized cardiopulmonary resuscitation, improved thermoregulation) and provision of cluster care in the neonatal intensive care unit (NICU). We identified key drivers to achieve our SMART aims, and implemented quality improvement (QI) cycles: initiation of the ICH bundle, education of NICU staff, and emphasis on sustained adherence. We excluded infants born outside our facility and those with congenital anomalies.

RESULTS

Using statistical process control analysis (p-chart), the ICH bundle was associated with successful reduction in severe ICH (grade 3-4) in our NICU from a prebundle rate of 24% (January 2012-December 2013) to a sustained reduction over the next 4 years to an average rate of 9.7% by December 2017. Results during 2016-2017 showed a sustained improvement beyond the goal for 2014-2015. Over the same interval, there was improvement in admission temperatures [median 36.1 °C (interquartile range: 35.3-36.7 °C) vs. 37.1 °C (36.8-37.5 °C), p < 0.01] and a decrease in mortality rate [pre: 16/117 (14%) vs. post: 16/281 (6%), P < 0.01].

CONCLUSION

Our multidisciplinary QI initiative decreased severe ICH in our institution from a baseline rate of 24% to a lower rate of 9.7% over the ensuing 4 years. Intensive focus on sustained implementation of an ICH bundle protocol consisting of improved delivery room management, thermoregulation, and clustered care in the NICU was temporally associated with a clinically significant reduction in severe ICH.

Relationship of resuscitation, respiratory function monitoring data and outcomes in preterm infants

Intraventricular haemorrhage (IVH) and bronchopulmonary dysplasia (BPD) are major complications of premature birth. We tested the hypotheses that prematurely born infants who developed an IVH or BPD would have high expiratory tidal volumes (V_TE) (V_TE > 6 ml/kg) and/or low-end tidal carbon dioxide (ETCO₂) levels (ETCO₂ levels < 4.5 kPa) as recorded by respiratory function monitoring or hyperoxia (oxygen saturation (SaO₂) > 95%) during resuscitation in the delivery suite. Seventy infants, median gestational age 27 weeks (range 23-33), were assessed; 31 developed an IVH and 43 developed BPD. Analysis was undertaken of 31,548 inflations. The duration of resuscitation did not differ significantly between the groups. Those who developed an IVH compared to those who did not had a greater number of inflations with a high V_TE and a low ETCO₂, which remained significant after correcting for differences in gestational age and birth weight between groups (p = 0.019). Differences between infants who did and did not develop BPD were not significant after correcting for differences in gestational age and birth weight. There were no significant differences in the duration of hyperoxia between the groups.Conclusions: Avoidance of high tidal volumes and hypocarbia in the delivery suite might reduce IVH development. What is known • Hypocarbia on the neonatal unit is associated with the development of intraventricular haemorrhage (IVH) and bronchopulmonary dysplasia (BPD). What is new • Infants who developed an IVH compared to those who did not had significantly more inflations with high expiratory tidal volumes and low ETCO₂s.

Big Data in Neonatal Health Care: Big Reach, Big Reward?

Analog-to-digital data conversion has created massive amounts of historical and real-time health care data. Costs associated with neonatal health issues are high. Big data use in the neonatal intensive care unit has the potential to facilitate earlier detection of clinical deterioration, expedite application of efficient clinical decision-making algorithms based on real-time and historical data mining, and yield significant cost-savings.

Synchronized Oscillations of Arterial Oxygen Saturation, Cerebral Tissue Oxygenation and Heart Rate in Preterm Neonates: Investigation of Long-Term Measurements with Multiple Einstein's Cross Wavelet Analysis

BACKGROUND

In preterm neonates, the cardiovascular and cerebral vascular control is immature, making the brain vulnerable to an increased incidence of hypoxic and hyperoxic episodes.

AIM

The aim of the study was to apply the recently developed multiple Einstein's cross wavelet analysis (MECWA) to quantify the coupling of fluctuations of peripherally measured arterial oxygen saturation (SpO₂), cerebral tissue oxygen saturation (StO₂) and heart rate (HR).

METHODS

Two long-term measurements on preterm neonates with a gestational age at birth of 26.4 and 26.8 weeks and a postnatal age of 2.1 and 3.9 weeks were analyzed. MECWA was applied to SpO₂, StO₂ and HR.

RESULTS

MECWA showed that the fluctuations of SpO₂, StO₂ and HR were synchronized in the low-frequency range with periods of ~1 h and ~0.5 h. The amplitudes of the synchronization frequencies were dependent on the individual neonate.

DISCUSSION

MECWA is a useful novel tool to assess the coupling of physiological signals. The parameters determined by MECWA seem to be related to the chronobiological processes, as well as constant regulations of the cardiovascular and cerebral perfusion state.

CONCLUSION

MECWA was able to identify long-term synchronization of the cardiovascular and cerebral perfusion state in preterm neonates with periods of ~1 h and ~0.5 h.

Does prolonged severe hypercapnia interfere with normal cerebrovascular function in piglets?

BACKGROUND

Hypercapnia causes cerebral vasodilation and increased cerebral blood flow (CBF). During prolonged hypercapnia it is unknown whether cerebral vasodilation persists and whether cerebrovascular function is preserved. We investigated the effects of prolonged severe hypercapnia on pial arteriolar diameters (PAD) and cerebrovascular reactivity to vasodilators and vasoconstrictors.

METHODS

Piglets were anesthetized, intubated and ventilated. Closed cranial windows were implanted to measure PAD. Changes in PAD were documented during hypercapnia (PaCO₂ 75-80 mm Hg). Cerebrovascular reactivity was documented during normocapnia and at 30, 60, and 120 min of hypercapnia.

RESULTS

Cerebral vasodilation to hypercapnia was sustained over 120 min. Cerebrovascular responses to vasodilators and vasoconstrictors were preserved during hypercapnia. During hypercapnia, vasodilatory responses to second vasodilators were similar to normocapnia, while exposure to vasoconstrictors caused significant vasoconstriction.

CONCLUSIONS

Prolonged severe hypercapnia causes sustained vasodilation of pial arteriolar diameters indicative of hyperperfusion. During hypercapnia, cerebral vascular responses to vasodilators and vasoconstrictors were preserved, suggesting that cerebral vascular function remained intact. Of note, cerebral vessels during hypercapnia were capable of further dilation when exposed to additional cerebral vasodilators and, significant vasoconstriction when exposed to vasoconstrictors. Extrapolating these findings to infants, we suggest that severe hypercapnia should be avoided, because it could cause/increase cerebrovascular injury.