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Fyfe KL, Odoi A, Yiallourou SR, Wong FY, Walker AM, Horne RS. Preterm Infants Exhibit Greater Variability in Cerebrovascular Control than Term Infants. Sleep 2015; 38:1411-21. [PMID: 25669192 PMCID: PMC4531409 DOI: 10.5665/sleep.4980] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 01/10/2015] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Sudden infant death syndrome (SIDS) remains an important cause of infant death, particularly among infants born preterm. Prone sleeping is the major risk factor for SIDS and this has recently been shown to alter cerebrovascular control in term infants. As preterm infants are at greater risk for SIDS than those born at term, we hypothesized that their cerebrovascular control in the prone position would be reduced compared to term infants. PATIENTS OR PARTICIPANTS There were 35 preterm (mean gestation 31.2 ± 0.4 w) and 17 term (mean gestation 40.1 ± 0.3 w) infants. DESIGN Infants underwent daytime polysomnography at 2-4 w, 2-3 mo, and 5-6 mo postterm age. Infants slept both prone and supine and were presented with cardiovascular challenges in the form of 15° head-up tilts (HUT). MEASUREMENTS AND RESULTS Cerebral tissue oxygenation index (TOI) was recorded using near-infrared spectroscopy (NIRO-200 spectrophotometer, Hamamatsu Photonics KK, Japan) and mean arterial pressure (MAP) was recorded using a Finometer cuff (Finapres Medical Systems, Amsterdam, The Netherlands). In the prone position TOI increased following the HUT (P < 0.05), whereas no change was seen in the supine position. The overall pattern of response was similar in both groups, but more variable in preterm than term infants (P < 0.05). CONCLUSIONS Cerebrovascular control differs between the prone and supine positions in preterm infants. Although overall the responses to head-up tilts were similar between term and preterm infants, greater variability of responses in preterm infants suggests persisting immaturity of their cerebrovascular control in the first year of life, which may contribute to their increased risk of sudden infant death syndrome.
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Affiliation(s)
- Karinna L. Fyfe
- The Ritchie Centre, Hudson Institute of Medical Research and Monash University, Melbourne, Victoria, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Alexsandria Odoi
- The Ritchie Centre, Hudson Institute of Medical Research and Monash University, Melbourne, Victoria, Australia
| | - Stephanie R. Yiallourou
- The Ritchie Centre, Hudson Institute of Medical Research and Monash University, Melbourne, Victoria, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Flora Y. Wong
- The Ritchie Centre, Hudson Institute of Medical Research and Monash University, Melbourne, Victoria, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
- Monash Newborn, Monash Medical Centre, Melbourne, Victoria, Australia
| | - Adrian M. Walker
- The Ritchie Centre, Hudson Institute of Medical Research and Monash University, Melbourne, Victoria, Australia
| | - Rosemary S.C. Horne
- The Ritchie Centre, Hudson Institute of Medical Research and Monash University, Melbourne, Victoria, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
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da Costa CS, Czosnyka M, Smielewski P, Mitra S, Stevenson GN, Austin T. Monitoring of Cerebrovascular Reactivity for Determination of Optimal Blood Pressure in Preterm Infants. J Pediatr 2015; 167:86-91. [PMID: 25891381 DOI: 10.1016/j.jpeds.2015.03.041] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 01/27/2015] [Accepted: 03/18/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To define levels of mean arterial blood pressure (MABP) where cerebrovascular reactivity is strongest in preterm infants (ie, optimal MABP, or MABPOPT) and correlate deviations from MABPOPT with mortality and intraventricular hemorrhage (IVH). STUDY DESIGN A total of 60 preterm infants born at median gestational age 26 ± 2 weeks (23 ± 2 to 32 ± 1) with indwelling arterial catheter were studied at a median 34 hours (range 5-228) of age. Tissue oxygenation heart rate (HR) reactivity index, which estimates cerebrovascular reactivity, was calculated as the moving correlation coefficient between slow waves of tissue oxygenation index, measured with near-infrared spectroscopy, and HR. MABPOPT was defined by dividing MABP into 2-mm Hg bins and averaging the tissue oxygenation HR reactivity index within those bins. A measurement of divergence from MABPOPT was calculated as the absolute difference between mean MABP and mean MABPOPT. RESULTS Individual MABPOPT was defined in 81% of the patients. A measurement of divergence from MABPOPT was greater in those patients who died (mean 4.2 mm Hg; 95% CI 3.33-4.96) compared with those who survived (mean 2.1 mm Hg; 95% CI 1.64-2.56), P = .013. Patients who had MABP lower than MABPOPT by 4 mm Hg or more had a greater rate of mortality (40%) than those with MABP close to or above MABPOPT (13%), P = .049. Patients with MABP greater than MABPOPT by 4 mm Hg had greater IVH scores, P = .042. CONCLUSIONS Continuous monitoring of cerebrovascular reactivity allows the determination of MABPOPT in preterm neonates. Significant deviation below MABPOPT was observed in infants who died. Deviation of MABP above optimal level was observed in infants who developed more severe IVH.
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Affiliation(s)
- Cristine Sortica da Costa
- Neonatal Unit, Rosie Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.
| | - Marek Czosnyka
- Department of Clinical Neurosciences, Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom; Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Peter Smielewski
- Department of Clinical Neurosciences, Academic Neurosurgical Unit, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Subhabrata Mitra
- Neonatal Unit, Elizabeth Garret Anderson Wing, University College London Hospital, London, United Kingdom
| | - Gordon N Stevenson
- Neonatal Unit, Rosie Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Topun Austin
- Neonatal Unit, Rosie Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
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Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping) improves systemic and cerebral oxygenation in preterm lambs. PLoS One 2015; 10:e0117504. [PMID: 25689406 PMCID: PMC4331493 DOI: 10.1371/journal.pone.0117504] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/26/2014] [Indexed: 11/23/2022] Open
Abstract
Background As measurement of arterial oxygen saturation (SpO2) is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known. Aim We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs. Methods Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2) were measured continuously in apnoeic preterm lambs (126±1 day gestation). Positive pressure ventilation was initiated either 1) prior to umbilical cord clamping, or 2) after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping. Results Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5–6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping. Conclusion The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.
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Rhee CJ, Fraser CD, Kibler K, Easley RB, Andropoulos DB, Czosnyka M, Varsos GV, Smielewski P, Rusin CG, Brady KM, Kaiser JR. The ontogeny of cerebrovascular pressure autoregulation in premature infants. J Perinatol 2014; 34:926-31. [PMID: 25010225 PMCID: PMC4383263 DOI: 10.1038/jp.2014.122] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 04/01/2014] [Accepted: 05/16/2014] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To quantify cerebrovascular autoregulation as a function of gestational age (GA) and across the phases of the cardiac cycle. STUDY DESIGN The present study is a hypothesis-generating re-analysis of previously published data. Premature infants (n=179) with a GA range of 23 to 33 weeks were monitored with umbilical artery catheters and transcranial Doppler insonation of the middle cerebral artery for 1-h sessions over the first week of life. Autoregulation was quantified by three methods, as a moving correlation coefficient between: (1) systolic arterial blood pressure (ABP) and systolic cerebral blood flow (CBF) velocity (Sx); (2) mean ABP and mean CBF velocity (Mx); and (3) diastolic ABP and diastolic CBF velocity (Dx). Comparisons of individual and cohort cerebrovascular pressure autoregulation were made across GA for each aspect of the cardiac cycle. RESULTS Systolic, mean and diastolic ABP increased with GA (r=0.3, 0.4 and 0.4; P<0.0001). Systolic CBF velocity was pressure-passive in infants with the lowest GA, and Sx decreased with advancing GA (r=-0.3; P<0.001), indicating increased capacity for cerebral autoregulation during systole during development. By contrast, Dx was elevated, indicating dysautoregulation, in all subjects and showed minimal change with advancing GA (r=-0.06; P=0.05). Multivariate analysis confirmed that both GA (P<0.001) and 'effective cerebral perfusion pressure' (ABP minus critical closing pressure (CrCP); P<0.01) were associated with Sx. CONCLUSION Premature infants have low and usually pressure-passive diastolic CBF velocity. By contrast, the regulation of systolic CBF velocity by pressure autoregulation developed in this cohort between 23 and 33 weeks GA. Elevated effective cerebral perfusion pressure derived from the CrCP was associated with dysautoregulation.
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Affiliation(s)
- Christopher J. Rhee
- Department of Pediatrics, Section of Neonatology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | | | - Kathleen Kibler
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Ronald B. Easley
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Dean B. Andropoulos
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Marek Czosnyka
- Division of Neurosurgery, Addenbrooke’s Hospital, Cambridge University, Cambridge, England
| | - Georgios V. Varsos
- Division of Neurosurgery, Addenbrooke’s Hospital, Cambridge University, Cambridge, England
| | - Peter Smielewski
- Division of Neurosurgery, Addenbrooke’s Hospital, Cambridge University, Cambridge, England
| | - Craig G. Rusin
- Department of Cardiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Ken M. Brady
- Departments of Pediatrics and Anesthesiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Jeffrey R. Kaiser
- Departments of Pediatrics and Obstetrics and Gynecology, Section of Neonatology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
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Eriksen VR, Hahn GH, Greisen G. Dopamine therapy is associated with impaired cerebral autoregulation in preterm infants. Acta Paediatr 2014; 103:1221-6. [PMID: 25266994 DOI: 10.1111/apa.12817] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/27/2014] [Accepted: 09/24/2014] [Indexed: 11/29/2022]
Abstract
AIM Hypotension is a common problem in newborn infants and is associated with increased mortality and morbidity. Dopamine is the most commonly used antihypotensive drug therapy, but has never been shown to improve neurological outcomes. This study tested our hypothesis that dopamine affects cerebral autoregulation (CA). METHODS Near-infrared spectroscopy was used to measure the cerebral oxygenation index in 60 very preterm infants, and mean arterial blood pressure was monitored towards the end of their first day of life. Measurements were performed continuously for two to three hour periods. CA was quantified as the cerebral oximetry index (COx). RESULTS We treated 13 of the 60 infants (22%) with dopamine during the measurements. COx was higher in the dopamine group than the untreated group (0.41 ± 0.25 vs. 0.08 ± 0.25, p < 0.001). Blood pressure tended to be lower in the dopamine group, but the anticipated difference in cerebral oxygenation was not detected. The need for mechanical ventilation in the first day of life and incidences of mortality was higher in the dopamine group. CONCLUSION Dopamine therapy was associated with decreased CA in preterm infants. We were unable to determine whether dopamine directly impaired CA or was merely an indicator of illness.
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Affiliation(s)
- Vibeke R. Eriksen
- Department of Neonatology; Copenhagen University Hospital - Rigshospitalet; Copenhagen Denmark
| | - Gitte H. Hahn
- Department of Neonatology; Copenhagen University Hospital - Rigshospitalet; Copenhagen Denmark
- Department of Paediatrics; Copenhagen University Hospital - Herlev Hospital; Herlev Denmark
| | - Gorm Greisen
- Department of Neonatology; Copenhagen University Hospital - Rigshospitalet; Copenhagen Denmark
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Mitra S, Czosnyka M, Smielewski P, O'Reilly H, Brady K, Austin T. Heart rate passivity of cerebral tissue oxygenation is associated with predictors of poor outcome in preterm infants. Acta Paediatr 2014; 103:e374-82. [PMID: 24844816 DOI: 10.1111/apa.12696] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 03/02/2014] [Accepted: 05/15/2014] [Indexed: 11/30/2022]
Abstract
AIM Near-infrared spectroscopy (NIRS) and transcranial Doppler (TCD) allow non-invasive assessment of cerebral haemodynamics. We assessed cerebrovascular reactivity in preterm infants by investigating the relationship between NIRS- and TCD-derived indices and correlating them with severity of clinical illness. METHODS We recorded the NIRS-derived cerebral tissue oxygenation index (TOI) and TCD-derived flow velocity (Fv), along with other physiological variables. Moving correlation coefficients between measurements of cerebral perfusion (TOI, Fv) and heart rate were calculated. We presumed that positivity of these correlation coefficients - tissue oxygenation heart rate reactivity index (TOHRx) and flow velocity heart rate reactivity index (FvHRx) - would indicate a direct relationship between cerebral perfusion and cardiac output representing impaired cerebrovascular autoregulation. RESULTS We studied 31 preterm infants at a median age of 2 days, born at a median gestational age of 26 + 1 weeks. TOHRx was significantly correlated with gestational age (R = -0.57, p = 0.007), birth weight (R = -0.58, p = 0.006) and the Clinical Risk Index for Babies II (R = 0.55, p = 0.0014). TOHRx and FvHRx were significantly correlated (R = 0.39, p = 0.028). CONCLUSION Heart rate has a key influence on cerebral haemodynamics in preterm infants, and TOHRx may be of diagnostic value in identifying impaired cerebrovascular reactivity leading to adverse clinical outcome.
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Affiliation(s)
- S Mitra
- Neonatal Unit; Rosie Hospital; Cambridge University Hospitals NHS Foundation Trust; Cambridge UK
| | - M Czosnyka
- Academic Neurosurgical Unit; Department of Neurosurgery; Addenbrooke's Hospital; University of Cambridge; Cambridge UK
| | - P Smielewski
- Academic Neurosurgical Unit; Department of Neurosurgery; Addenbrooke's Hospital; University of Cambridge; Cambridge UK
| | - H O'Reilly
- Neonatal Unit; Norfolk and Norwich University Hospitals NHS Foundation Trust; Norwich UK
| | - K Brady
- Department of Anesthesiology and Critical Care Medicine; John Hopkins University School of Medicine; Baltimore MD USA
| | - T Austin
- Neonatal Unit; Rosie Hospital; Cambridge University Hospitals NHS Foundation Trust; Cambridge UK
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Williams M, Lee JK. Intraoperative blood pressure and cerebral perfusion: strategies to clarify hemodynamic goals. Paediatr Anaesth 2014; 24:657-67. [PMID: 24725244 PMCID: PMC4154320 DOI: 10.1111/pan.12401] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2014] [Indexed: 01/24/2023]
Abstract
Blood pressure can vary considerably during anesthesia. If blood pressure falls outside the limits of cerebrovascular autoregulation, children can become at risk of cerebral ischemic or hyperemic injury. However, the blood pressure limits of autoregulation are unclear in infants and children, and these limits can shift after brain injury. This article will review autoregulation, considerations for the hemodynamic management of children with brain injuries, and research on autoregulation monitoring techniques.
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Affiliation(s)
- Monica Williams
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, USA
| | - Jennifer K. Lee
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, USA
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Polglase GR, Miller SL, Barton SK, Kluckow M, Gill AW, Hooper SB, Tolcos M. Respiratory support for premature neonates in the delivery room: effects on cardiovascular function and the development of brain injury. Pediatr Res 2014; 75:682-8. [PMID: 24614803 DOI: 10.1038/pr.2014.40] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 12/16/2013] [Indexed: 02/02/2023]
Abstract
The transition to newborn life in preterm infants is complicated by immature cardiovascular and respiratory systems. Consequently, preterm infants often require respiratory support immediately after birth. Although aeration of the lung underpins the circulatory transition at birth, positive pressure ventilation can adversely affect cardiorespiratory function during this vulnerable period, reducing pulmonary blood flow and left ventricular output. Furthermore, pulmonary volutrauma is known to initiate pulmonary inflammatory responses, resulting in remote systemic involvement. This review focuses on the downstream consequences of positive pressure ventilation, in particular, interactions between cardiovascular output and the initiation of a systemic inflammatory cascade, on the immature brain. Recent studies have highlighted that positive pressure ventilation strategies are precursors of cerebral injury, probably mediated through cerebral blood flow instability. The presence of, or initiation of, an inflammatory cascade accentuates adverse cerebral blood flow, in addition to being a direct source of brain injury. Importantly, the degree of brain injury is dependent on the nature of the initial ventilation strategy used.
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Affiliation(s)
- Graeme R Polglase
- 1] The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Samantha K Barton
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
| | - Martin Kluckow
- Department of Neonatalogy, Royal North Shore Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, The University of Western Australia, Western Australia, Australia
| | - Stuart B Hooper
- 1] The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia [2] Department of Obstetrics and Gynecology, Monash University, Clayton, Victoria, Australia
| | - Mary Tolcos
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
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Brew N, Walker D, Wong FY. Cerebral vascular regulation and brain injury in preterm infants. Am J Physiol Regul Integr Comp Physiol 2014; 306:R773-86. [PMID: 24647591 DOI: 10.1152/ajpregu.00487.2013] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebrovascular lesions, mainly germinal matrix hemorrhage and ischemic injury to the periventricular white matter, are major causes of adverse neurodevelopmental outcome in preterm infants. Cerebrovascular lesions and neuromorbidity increase with decreasing gestational age, with the white matter predominantly affected. Developmental immaturity in the cerebral circulation, including ongoing angiogenesis and vasoregulatory immaturity, plays a major role in the severity and pattern of preterm brain injury. Prevention of this injury requires insight into pathogenesis. Cerebral blood flow (CBF) is low in the preterm white matter, which also has blunted vasoreactivity compared with other brain regions. Vasoreactivity in the preterm brain to cerebral perfusion pressure, oxygen, carbon dioxide, and neuronal metabolism is also immature. This could be related to immaturity of both the vasculature and vasoactive signaling. Other pathologies arising from preterm birth and the neonatal intensive care environment itself may contribute to impaired vasoreactivity and ineffective CBF regulation, resulting in the marked variations in cerebral hemodynamics reported both within and between infants depending on their clinical condition. Many gaps exist in our understanding of how neonatal treatment procedures and medications have an impact on cerebral hemodynamics and preterm brain injury. Future research directions for neuroprotective strategies include establishing cotside, real-time clinical reference values for cerebral hemodynamics and vasoregulatory capacity and to demonstrate that these thresholds improve long-term outcomes for the preterm infant. In addition, stimulation of vascular development and repair with growth factor and cell-based therapies also hold promise.
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Affiliation(s)
- Nadine Brew
- The Ritchie Centre, Monash Institute of Medical Research-Prince Henry's Institute, Melbourne, Clayton, Victoria, Australia; and
| | - David Walker
- The Ritchie Centre, Monash Institute of Medical Research-Prince Henry's Institute, Melbourne, Clayton, Victoria, Australia; and Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Flora Y Wong
- The Ritchie Centre, Monash Institute of Medical Research-Prince Henry's Institute, Melbourne, Clayton, Victoria, Australia; and Monash Newborn, Monash Medical Centre, Melbourne, Victoria, Australia; and Department of Pediatrics, Monash University, Melbourne, Victoria, Australia
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Verhagen EA, Hummel LA, Bos AF, Kooi EM. Near-infrared spectroscopy to detect absence of cerebrovascular autoregulation in preterm infants. Clin Neurophysiol 2014; 125:47-52. [DOI: 10.1016/j.clinph.2013.07.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 05/23/2013] [Accepted: 07/03/2013] [Indexed: 11/28/2022]
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Chakkarapani E, Dingley J, Aquilina K, Osredkar D, Liu X, Thoresen M. Effects of xenon and hypothermia on cerebrovascular pressure reactivity in newborn global hypoxic-ischemic pig model. J Cereb Blood Flow Metab 2013; 33:1752-60. [PMID: 23899927 PMCID: PMC3824173 DOI: 10.1038/jcbfm.2013.123] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/22/2013] [Accepted: 07/01/2013] [Indexed: 12/29/2022]
Abstract
Autoregulation of cerebral perfusion is impaired in hypoxic-ischemic encephalopathy. We investigated whether cerebrovascular pressure reactivity (PRx), an element of cerebral autoregulation that is calculated as a moving correlation coefficient between averages of intracranial and mean arterial blood pressure (MABP) with values between -1 and +1, is impaired during and after a hypoxic-ischemic insult (HI) in newborn pigs. Associations between end-tidal CO2, seizures, neuropathology, and PRx were investigated. The effect of hypothermia (HT) and Xenon (Xe) on PRx was studied. Pigs were randomized to Sham, and after HI to normothermia (NT), HT, Xe or xenon hypothermia (XeHT). We defined PRx >0.2 as peak and negative PRx as preserved. Neuropathology scores after 72 hours of survival was grouped as 'severe' or 'mild.' Secondary PRx peak during recovery, predictive of severe neuropathology and associated with insult severity (P=0.05), was delayed in HT (11.5 hours) than in NT (6.5 hours) groups. Seizures were associated with impaired PRx in NT pigs (P=0.0002), but not in the HT/XeHT pigs. PRx was preserved during normocapnia and impaired during hypocapnia. Xenon abolished the secondary PRx peak, increased (mean (95% confidence interval (CI)) MABP (6.5 (3.8, 9.4) mm Hg) and cerebral perfusion pressure (5.9 (2.9, 8.9) mm Hg) and preserved the PRx (regression coefficient, -0.098 (95% CI (-0.18, -0.01)), independent of the insult severity.
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Howlett JA, Northington FJ, Gilmore MM, Tekes A, Huisman TA, Parkinson C, Chung SE, Jennings JM, Jamrogowicz JJ, Larson AC, Lehmann CU, Jackson E, Brady KM, Koehler RC, Lee JK. Cerebrovascular autoregulation and neurologic injury in neonatal hypoxic-ischemic encephalopathy. Pediatr Res 2013; 74:525-35. [PMID: 23942555 PMCID: PMC3954983 DOI: 10.1038/pr.2013.132] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 01/31/2013] [Indexed: 12/12/2022]
Abstract
BACKGROUND Neonates with hypoxic-ischemic encephalopathy (HIE) are at risk of cerebral blood flow dysregulation. Our objective was to describe the relationship between autoregulation and neurologic injury in HIE. METHODS Neonates with HIE had autoregulation monitoring with the hemoglobin volume index (HVx) during therapeutic hypothermia, rewarming, and the first 6 h of normothermia. The 5-mm Hg range of mean arterial blood pressure (MAP) with best vasoreactivity (MAPOPT) was identified. The percentage of time spent with MAP below MAPOPT and deviation in MAP from MAPOPT were measured. Neonates received brain magnetic resonance imaging (MRI) 3-7 d after treatment. MRIs were coded as no, mild, or moderate/severe injury in five regions. RESULTS HVx identified MAPOPT in 79% (19/24), 77% (17/22), and 86% (18/21) of the neonates during hypothermia, rewarming, and normothermia, respectively. Neonates with moderate/severe injury in paracentral gyri, white matter, basal ganglia, and thalamus spent a greater proportion of time with MAP below MAPOPT during rewarming than neonates with no or mild injury. Neonates with moderate/severe injury in paracentral gyri, basal ganglia, and thalamus had greater MAP deviation below MAPOPT during rewarming than neonates without injury. CONCLUSION Maintaining MAP within or above MAPOPT may reduce the risk of neurologic injuries in neonatal HIE.
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Affiliation(s)
- Jessica A. Howlett
- Department of Pediatrics, Division of Neonatology, Johns Hopkins University School of Medicine (JHU), Baltimore, MD,Neurosciences Intensive Care Nursery Program, JHU
| | - Frances J. Northington
- Department of Pediatrics, Division of Neonatology, Johns Hopkins University School of Medicine (JHU), Baltimore, MD,Neurosciences Intensive Care Nursery Program, JHU
| | - Maureen M. Gilmore
- Department of Pediatrics, Division of Neonatology, Johns Hopkins University School of Medicine (JHU), Baltimore, MD,Neurosciences Intensive Care Nursery Program, JHU
| | - Aylin Tekes
- Neurosciences Intensive Care Nursery Program, JHU,Department of Radiology, Division of Pediatric Radiology, JHU
| | - Thierry A.G.M. Huisman
- Neurosciences Intensive Care Nursery Program, JHU,Department of Radiology, Division of Pediatric Radiology, JHU
| | - Charlamaine Parkinson
- Department of Pediatrics, Division of Neonatology, Johns Hopkins University School of Medicine (JHU), Baltimore, MD,Neurosciences Intensive Care Nursery Program, JHU
| | - Shang-En Chung
- Department of Pediatrics, Division of General Pediatrics and Adolescent Medicine, JHU,Center for Child and Community Health Research (CCHR), JHU
| | - Jacky M. Jennings
- Department of Pediatrics, Division of General Pediatrics and Adolescent Medicine, JHU,Center for Child and Community Health Research (CCHR), JHU
| | | | - Abby C. Larson
- Department of Anesthesiology and Critical Care Medicine, JHU
| | - Christoph U. Lehmann
- Department of Pediatrics, Division of Neonatology, Johns Hopkins University School of Medicine (JHU), Baltimore, MD
| | - Eric Jackson
- Department of Anesthesiology and Critical Care Medicine, JHU
| | - Ken M. Brady
- Department of Anesthesiology, Texas Children’s Hospital, Houston, TX
| | | | - Jennifer K. Lee
- Neurosciences Intensive Care Nursery Program, JHU,Department of Anesthesiology and Critical Care Medicine, JHU
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The development of cardiovascular and cerebral vascular control in preterm infants. Sleep Med Rev 2013; 18:299-310. [PMID: 23907095 DOI: 10.1016/j.smrv.2013.06.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 06/20/2013] [Accepted: 06/25/2013] [Indexed: 11/21/2022]
Abstract
Over the past three decades there has been a steady increase in the incidence of preterm birth. The worldwide rate of preterm birth is estimated to be 9.6% of all births, a total of almost 13 million births annually. Preterm birth is associated with a range of adverse cardiovascular and central nervous system outcomes, which may be attributed to altered development of these systems following preterm birth. Preterm birth has a considerable impact on cardiovascular parameters with preterm infants displaying higher heart rates and reduced blood pressure when compared to term born infants at matched ages. Furthermore, premature infants have altered autonomic control of cardiovascular parameters which manifests as abnormalities in heart rate variability and baroreflex mediated control of heart rate and blood pressure. As a result, systemic cardiovascular parameters can be unstable following preterm birth which may place stress on the neonatal brain. The brain of a preterm infant is particularly vulnerable to these fluctuations due to immature cerebral haemodynamics. Preterm infants, particularly those who are very preterm or unwell, display fluctuating pressure-passivity between systemic blood pressure and cerebral blood flow representing a considerably increased risk of cerebral haemorrhage or hypoxia. This is further compounded by immaturity of cerebral blood flow-metabolism coupling, which means increased metabolic demand cannot adequately be met by increased cerebral blood flow. It has been suggested that adverse long-term outcomes following preterm birth may occur as a result of exposure to physiological stress either in-utero or early in infancy.
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Stewart A, Tekes A, Huisman TA, Jennings JM, Allen MC, Northington FJ, Everett AD, Graham EM. Glial fibrillary acidic protein as a biomarker for periventricular white matter injury. Am J Obstet Gynecol 2013; 209:27.e1-7. [PMID: 23467054 DOI: 10.1016/j.ajog.2013.02.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 01/28/2013] [Accepted: 02/27/2013] [Indexed: 10/27/2022]
Abstract
OBJECTIVE Periventricular white matter injury (PWMI), a precursor of cerebral palsy, traditionally is not diagnosed until 6 weeks of life by head ultrasound scanning. We sought to determine whether early neonatal glial fibrillary acidic protein (GFAP) levels could identify PWMI in low birthweight (<2500 g) infants. STUDY DESIGN Each case with PWMI on head ultrasound scanning at 6 weeks of life from April 2009 to April 2011 was matched by gestational age and mode of delivery to 2 subsequent neonates with a normal head ultrasound scan. GFAP was measured in cord blood at birth, at neonatal intensive care unit admission, and on days 1-4 of life. RESULTS During this 2-year period, 21 cases with PWMI with gestational age 27.4 ± 3.3 weeks were compared with 42 control infants. The incidence of cesarean delivery was 61.9% in both groups. GFAP was not significantly different in cord blood or at neonatal intensive care unit admission but was significantly elevated on day 1 (median, 5-95%; 0, 0-0.98 ng/mL cases; 0, 0-0.06 ng/mL control infants; P = .03), day 2 (0, 0-1.21 ng/mL; 0, 0-0.05 ng/mL, respectively; P = .02), day 3 (0.05, 0-0.33 ng/mL; 0, 0-0.04 ng/mL, respectively; P = .004), and day 4 (0.02, 0-1.03 ng/mL; 0, 0-0.05 ng/mL, respectively; P < .001). The odds of the development of PWMI significantly increased with increasing levels of GFAP from day 1-4 of life when adjustment was made for preeclampsia, antenatal steroid administration, and neonatal chronic lung disease. CONCLUSION The ability to predict PWMI with a blood test for GFAP shortly after birth opens the possibility for rapid identification of infants for early intervention and provides a benchmark for the qualification of new therapies to improve neurodevelopmental outcomes.
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Batton B, Li L, Newman NS, Das A, Watterberg KL, Yoder BA, Faix RG, Laughon MM, Stoll BJ, Van Meurs KP, Carlo WA, Poindexter BB, Bell EF, Sánchez PJ, Ehrenkranz RA, Goldberg RN, Laptook AR, Kennedy KA, Frantz ID, Shankaran S, Schibler K, Higgins RD, Walsh MC. Use of antihypotensive therapies in extremely preterm infants. Pediatrics 2013; 131:e1865-73. [PMID: 23650301 PMCID: PMC3666108 DOI: 10.1542/peds.2012-2779] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To investigate the relationships among blood pressure (BP) values, antihypotensive therapies, and in-hospital outcomes to identify a BP threshold below which antihypotensive therapies may be beneficial. METHODS Prospective observational study of infants 23(0/7) to 26(6/7) weeks' gestational age. Hourly BP values and antihypotensive therapy use in the first 24 hours were recorded. Low BP was investigated by using 15 definitions. Outcomes were examined by using regression analysis controlling for gestational age, the number of low BP values, and illness severity. RESULTS Of 367 infants enrolled, 203 (55%) received at least 1 antihypotensive therapy. Treated infants were more likely to have low BP by any definition (P < .001), but for the 15 definitions of low BP investigated, therapy was not prescribed to 3% to 49% of infants with low BP and, paradoxically, was administered to 28% to 41% of infants without low BP. Treated infants were more likely than untreated infants to develop severe retinopathy of prematurity (15% vs 8%, P = .03) or severe intraventricular hemorrhage (22% vs 11%, P < .01) and less likely to survive (67% vs 78%, P = .02). However, with regression analysis, there were no significant differences between groups in survival or in-hospital morbidity rates. CONCLUSIONS Factors other than BP contributed to the decision to use antihypotensive therapies. Infant outcomes were not improved with antihypotensive therapy for any of the 15 definitions of low BP investigated.
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Affiliation(s)
- Beau Batton
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
| | - Lei Li
- Statistics & Epidemiology Unit, RTI International, Research Triangle Park, North Carolina
| | - Nancy S. Newman
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
| | - Abhik Das
- Statistics & Epidemiology Unit, RTI International, Rockville, Maryland
| | | | - Bradley A. Yoder
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Roger G. Faix
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Matthew M. Laughon
- Department of Pediatrics, University of North Carolina, Chapel Hill, North Carolina
| | - Barbara J. Stoll
- Department of Pediatrics, Emory University School of Medicine & Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Krisa P. Van Meurs
- Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California
| | - Waldemar A. Carlo
- Division of Neonatology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Brenda B. Poindexter
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Edward F. Bell
- Department of Pediatrics, University of Iowa, Iowa City, Iowa
| | - Pablo J. Sánchez
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Richard A. Ehrenkranz
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut
| | | | - Abbot R. Laptook
- Department of Pediatrics, Women & Infants’ Hospital, Brown University, Providence, Rhode Island
| | - Kathleen A. Kennedy
- Department of Pediatrics, University of Texas Medical School at Houston, Houston, Texas
| | - Ivan D. Frantz
- Division of Newborn Medicine, Department of Pediatrics, Floating Hospital for Children, Tufts Medical Center, Boston, Massachusetts
| | - Seetha Shankaran
- Department of Pediatrics, Wayne State University, Detroit, Michigan
| | - Kurt Schibler
- Department of Pediatrics, Cincinnati Children’s Hospital Medical Center & University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Rosemary D. Higgins
- Eunice Kennedy Shriver National Institute of Child Health & Human Development, National Institutes of Health, Bethesda, Maryland
| | - Michele C. Walsh
- Department of Pediatrics, Rainbow Babies & Children’s Hospital, Case Western Reserve University, Cleveland, Ohio
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Lee JK, Williams M, Jennings JM, Jamrogowicz JL, Larson AC, Jordan LC, Heitmiller ES, Hogue CW, Ahn ES. Cerebrovascular autoregulation in pediatric moyamoya disease. Paediatr Anaesth 2013; 23:547-56. [PMID: 23506446 PMCID: PMC3648623 DOI: 10.1111/pan.12140] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/29/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND Moyamoya syndrome carries a high risk of cerebral ischemia, and impaired cerebrovascular autoregulation may play a critical role. Autoregulation indices derived from near-infrared spectroscopy (NIRS) may clarify hemodynamic goals that conform to the limits of autoregulation. OBJECTIVES The aims of this pilot study were to determine whether the NIRS-derived indices could identify blood pressure ranges that optimize autoregulation and whether autoregulatory function differs between anatomic sides in patients with unilateral vasculopathy. METHODS Pediatric patients undergoing indirect surgical revascularization for moyamoya were enrolled sequentially. NIRS-derived autoregulation indices, the cerebral oximetry index (COx) and the hemoglobin volume index (HVx), were calculated intraoperatively and postoperatively to measure autoregulatory function. The 5-mmHg ranges of optimal mean arterial blood pressure (MAPOPT ) with best autoregulation and the lower limit of autoregulation (LLA) were identified. RESULTS Of seven enrolled patients (aged 2-16 years), six had intraoperative and postoperative autoregulation monitoring and one had only intraoperative monitoring. Intraoperative MAPOPT was identified in six (86%) of seven patients with median values of 60-80 mmHg. Intraoperative LLA was identified in three (43%) patients with median values of 55-65 mmHg. Postoperative MAPOPT was identified in six (100%) of six patients with median values of 70-90 mmHg. Patients with unilateral disease had higher intraoperative HVx (P = 0.012) on side vasculopathy. CONCLUSIONS NIRS-derived indices may identify hemodynamic goals that optimize autoregulation in pediatric moyamoya.
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Affiliation(s)
- Jennifer K. Lee
- Dept. of Anesthesiology and Critical Care Medicine, Division of Pediatric Anesthesia, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Monica Williams
- Dept. of Anesthesiology and Critical Care Medicine, Division of Pediatric Anesthesia, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jacky M. Jennings
- The Bloomberg School of Public Health, Baltimore, MD, and The Dept. of Pediatrics, The Johns Hopkins University School of Medicine, USA
| | - Jessica L. Jamrogowicz
- Dept. of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Abby C. Larson
- Dept. of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lori C. Jordan
- Dept. of Neurology, Vanderbilt University, Nashville, TN, USA
| | - Eugenie S. Heitmiller
- Dept. of Anesthesiology and Critical Care Medicine, Division of Pediatric Anesthesia, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Charles W. Hogue
- Dept. of Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Edward S. Ahn
- Dept. of Neurosurgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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The consequences of chorioamnionitis: preterm birth and effects on development. J Pregnancy 2013; 2013:412831. [PMID: 23533760 PMCID: PMC3606792 DOI: 10.1155/2013/412831] [Citation(s) in RCA: 179] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 01/28/2013] [Accepted: 02/10/2013] [Indexed: 11/18/2022] Open
Abstract
Preterm birth is a major cause of perinatal mortality and long-term morbidity. Chorioamnionitis is a common cause of preterm birth. Clinical chorioamnionitis, characterised by maternal fever, leukocytosis, tachycardia, uterine tenderness, and preterm rupture of membranes, is less common than subclinical/histologic chorioamnionitis, which is asymptomatic and defined by inflammation of the chorion, amnion, and placenta. Chorioamnionitis is often associated with a fetal inflammatory response. The fetal inflammatory response syndrome (FIRS) is defined by increased systemic inflammatory cytokine concentrations, funisitis, and fetal vasculitis. Clinical and epidemiological studies have demonstrated that FIRS leads to poor cardiorespiratory, neurological, and renal outcomes. These observations are further supported by experimental studies that have improved our understanding of the mechanisms responsible for these outcomes. This paper outlines clinical and experimental studies that have improved our current understanding of the mechanisms responsible for chorioamnionitis-induced preterm birth and explores the cellular and physiological mechanisms underlying poor cardiorespiratory, neural, retinal, and renal outcomes observed in preterm infants exposed to chorioamnionitis.
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Rhee CJ, Kibler KK, Brady KM, Everett AD, Graham EM, Andropoulos DB, Easley RB. Detection of neurologic injury using vascular reactivity monitoring and glial fibrillary acidic protein. Pediatrics 2013; 131:e950-4. [PMID: 23420921 DOI: 10.1542/peds.2012-1702] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
New noninvasive methods for monitoring cerebrovascular pressure reactivity coupled with a blood-based assay for brain-specific injury in preterm infants could allow early diagnosis of brain injury and set the stage for improved timing and effectiveness of interventions. Using an adaptation of near-infrared spectroscopy, we report a case of a very low birth weight infant undergoing hemoglobin volume index monitoring as a measure of cerebrovascular pressure reactivity. During the monitoring period, this infant demonstrated significant disturbances in cerebrovascular pressure reactivity that coincided with elevation of serum glial fibrillary acidic protein and new findings of brain injury on head ultrasound. This case report demonstrates the potential of emerging noninvasive monitoring methods to assist in both detection and therapeutic management to improve neurologic outcomes of the very low birth weight neonate.
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Affiliation(s)
- Christopher J Rhee
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, Houston, TX 77030, USA.
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Bhatt S, Alison BJ, Wallace EM, Crossley KJ, Gill AW, Kluckow M, te Pas AB, Morley CJ, Polglase GR, Hooper SB. Delaying cord clamping until ventilation onset improves cardiovascular function at birth in preterm lambs. J Physiol 2013; 591:2113-26. [PMID: 23401615 DOI: 10.1113/jphysiol.2012.250084] [Citation(s) in RCA: 299] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Delayed cord clamping improves circulatory stability in preterm infants at birth, but the underlying physiology is unclear. We investigated the effects of umbilical cord clamping, before and after ventilation onset, on cardiovascular function at birth. Prenatal surgery was performed on lambs (123 days) to implant catheters into the pulmonary and carotid arteries and probes to measure pulmonary (PBF), carotid (CaBF) and ductus arteriosus blood flows. Lambs were delivered at 126 ± 1 days and: (1) the umbilical cord was clamped at delivery and ventilation was delayed for about 2 min (Clamp 1st; n = 6), and (2) umbilical cord clamping was delayed for 3-4 min, until after ventilation was established (Vent 1st; n = 6). All lambs were subsequently ventilated for 30 min. In Clamp 1st lambs, cord clamping rapidly (within four heartbeats), but transiently, increased pulmonary and carotid arterial pressures (by ∼30%) and CaBF (from 30.2 ± 5.6 to 40.1 ± 4.6 ml min(-1) kg(-1)), which then decreased again within 30-60 s. Following ventilation onset, these parameters rapidly increased again. In Clamp 1st lambs, cord clamping reduced heart rate (by ∼40%) and right ventricular output (RVO; from 114.6 ± 14.4 to 38.8 ± 9.7 ml min(-1) kg(-1)), which were restored by ventilation. In Vent 1st lambs, cord clamping reduced RVO from 153.5 ± 3.8 to 119.2 ± 10.6 ml min(-1) kg(-1), did not affect heart rates and resulted in stable blood flows and pressures during transition. Delaying cord clamping for 3-4 min until after ventilation is established improves cardiovascular function by increasing pulmonary blood flow before the cord is clamped. As a result, cardiac output remains stable, leading to a smoother cardiovascular transition throughout the early newborn period.
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Affiliation(s)
- Sasmira Bhatt
- Ritchie Centre, Monash Institute of Medical Research, Monash University, Clayton, Victoria, Australia
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Rhee CJ, Kibler KK, Easley RB, Andropoulos DB, Czosnyka M, Smielewski P, Brady KM. Renovascular reactivity measured by near-infrared spectroscopy. J Appl Physiol (1985) 2012; 113:307-14. [DOI: 10.1152/japplphysiol.00024.2012] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypotension and shock are risk factors for death, renal insufficiency, and stroke in preterm neonates. Goal-directed neonatal hemodynamic management lacks end-organ monitoring strategies to assess the adequacy of perfusion. Our aim is to develop a clinically viable, continuous metric of renovascular reactivity to gauge renal perfusion during shock. We present the renovascular reactivity index (RVx), which quantifies passivity of renal blood volume to spontaneous changes in arterial blood pressure. We tested the ability of the RVx to detect reductions in renal blood flow. Hemorrhagic shock was induced in 10 piglets. The RVx was monitored as a correlation between slow waves of arterial blood pressure and relative total hemoglobin (rTHb) obtained with reflectance near-infrared spectroscopy (NIRS) over the kidney. The RVx was compared with laser-Doppler measurements of red blood cell flux, and renal laser-Doppler measurements were compared with cerebral laser-Doppler measurements. Renal blood flow decreased to 75%, 50%, and 25% of baseline at perfusion pressures of 60, 45, and 40 mmHg, respectively, whereas in the brain these decrements occurred at pressures of 30, 25, and 15 mmHg, respectively. The RVx compared favorably to the renal laser-Doppler data. Areas under the receiver operator characteristic curves using renal blood flow thresholds of 50% and 25% of baseline were 0.85 (95% CI, 0.83–0.87) and 0.90 (95% CI, 0.88–0.92). Renovascular autoregulation can be monitored and is impaired in advance of cerebrovascular autoregulation during hemorrhagic shock.
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Affiliation(s)
- Christopher J. Rhee
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital/Baylor College of Medicine, Houston, Texas
| | - Kathleen K. Kibler
- Departments of Anesthesiology, Critical Care Medicine, and Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, Texas
| | - R. Blaine Easley
- Departments of Anesthesiology, Critical Care Medicine, and Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, Texas
| | - Dean B. Andropoulos
- Departments of Anesthesiology, Critical Care Medicine, and Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, Texas
| | - Marek Czosnyka
- Department of Academic Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Peter Smielewski
- Department of Academic Neurosurgery, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Ken M. Brady
- Departments of Anesthesiology, Critical Care Medicine, and Pediatrics, Texas Children's Hospital/Baylor College of Medicine, Houston, Texas
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Cerebral autoregulation in the first day after preterm birth: no evidence of association with systemic inflammation. Pediatr Res 2012; 71:253-60. [PMID: 22278187 DOI: 10.1038/pr.2011.46] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Both systemic inflammation and impaired cerebral autoregulation (CA) have been associated with brain injury in preterm infants. We hypothesized that impaired CA represents a hemodynamic link between inflammation and brain injury. RESULTS Neither fetal vasculitis nor interleukin-6 (IL-6) affected CA significantly. A high level of IL-6 was associated with hypotension (P = 0.03) irrespective of dopamine therapy. The magnitude of impairment in CA increased with decreasing mean arterial blood pressure (MAP) (P = 0.02). No significant associations were found between these parameters and either intraventricular hemorrhage (IVH) (n = 10) or neonatal mortality (n = 8). DISCUSSION In conclusion, postnatal inflammation was weakly associated with arterial hypotension, and hypotension was weakly associated with impaired autoregulation. There was no direct association, however, between autoregulation and antenatal or postnatal signs of inflammation. METHODS In our study, 60 infants (mean (±SD) of gestational age (GA) 27 (±1.3) wk) underwent continuous recording of MAP and cerebral oxygenation index (OI) by means of near-infrared spectroscopy (NIRS) for 2.3 ± 0.5 h, starting 18 ± 9 h after birth. Coherence and transfer function gain between MAP and OI represented the presence and degree of impairment of CA, respectively. We considered fetal vasculitis (placenta histology) to be an antenatal marker of inflammation, and used the level of IL-6 in blood, measured at 18 ± 10 h after birth, as a postnatal marker of inflammation. Definition of hypotension was MAP (mm Hg) ≤ GA (wk).
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Lee JK, Yang ZJ, Wang B, Larson AC, Jamrogowicz JL, Kulikowicz E, Kibler KK, Mytar JO, Carter EL, Burman HT, Brady KM, Smielewski P, Czosnyka M, Koehler RC, Shaffner DH. Noninvasive autoregulation monitoring in a swine model of pediatric cardiac arrest. Anesth Analg 2012; 114:825-36. [PMID: 22314692 DOI: 10.1213/ane.0b013e31824762d5] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Cerebrovascular autoregulation after resuscitation has not been well studied in an experimental model of pediatric cardiac arrest. Furthermore, developing noninvasive methods of monitoring autoregulation using near-infrared spectroscopy (NIRS) would be clinically useful in guiding neuroprotective hemodynamic management after pediatric cardiac arrest. We tested the hypotheses that the lower limit of autoregulation (LLA) would shift to a higher arterial blood pressure between 1 and 2 days of recovery after cardiac arrest and that the LLA would be detected by NIRS-derived indices of autoregulation in a swine model of pediatric cardiac arrest. We also tested the hypothesis that autoregulation with hypertension would be impaired after cardiac arrest. METHODS Data on LLA were obtained from neonatal piglets that had undergone hypoxic-asphyxic cardiac arrest and recovery for 1 day (n = 8) or 2 days (n = 8), or that had undergone sham surgery with 2 days of recovery (n = 8). Autoregulation with hypertension was examined in a separate cohort of piglets that underwent hypoxic-asphyxic cardiac arrest (n = 5) or sham surgery (n = 5) with 2 days of recovery. After the recovery period, piglets were reanesthetized, and autoregulation was monitored by standard laser-Doppler flowmetry and autoregulation indices derived from NIRS (the cerebral oximetry [COx] and hemoglobin volume [HVx] indices). The LLA was determined by decreasing blood pressure through inflation of a balloon catheter in the inferior vena cava. Autoregulation during hypertension was evaluated by inflation of an aortic balloon catheter. RESULTS The LLAs were similar between sham-operated piglets and piglets that recovered for 1 or 2 days after arrest. The NIRS-derived indices accurately detected the LLA determined by laser-Doppler flowmetry. The area under the curve of the receiver operator characteristic curve for cerebral oximetry index was 0.91 at 1 day and 0.92 at 2 days after arrest. The area under the curve for hemoglobin volume index was 0.92 and 0.89 at the respective time points. During induced hypertension, the static rate of autoregulation, defined as the percentage change in cerebrovascular resistance divided by the percentage change in cerebral perfusion pressure, was not different between postarrest and sham-operated piglets. At 2 days recovery from arrest, piglets exhibited neurobehavioral deficits and histologic neuronal injury. CONCLUSIONS In a swine model of pediatric hypoxic-asphyxic cardiac arrest with confirmed brain damage, the LLA did not differ 1 and 2 days after resuscitation. The NIRS-derived indices accurately detected the LLA in comparison with laser-Doppler flow measurements at those time points. Autoregulation remained functional during hypertension.
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Affiliation(s)
- Jennifer K Lee
- Department of Pediatric Anesthesiology and Critical Care Medicine, Johns Hopkins University, Blalock 904, 600 N. Wolfe Street, Baltimore, MD 21287, USA.
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