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Yamashiro SM, Iyer NP. Infant periodic breathing and apneic threshold. Physiol Rep 2024; 12:e15915. [PMID: 38243332 PMCID: PMC10799198 DOI: 10.14814/phy2.15915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 12/30/2023] [Accepted: 12/30/2023] [Indexed: 01/21/2024] Open
Abstract
A mathematical model was proposed to predict the role played by apneic threshold in periodic breathing in preterm infants. Prior models have mainly applied linear control theory which predicted instability but could not explain sustained periodic breathing. Apneic threshold to CO2 which has been postulated to play a major role in infant periodic breathing is a nonlinear effect and cannot be described by linear theory. Another previously unexplored nonlinear factor affecting instability is brain vascular volume change with CO2 which affects time delay to chemoreceptors. The current model explored the influences of apneic threshold, central and peripheral chemoreceptor gains, cardiac output, lung volume, and circulatory time delay on periodic breathing. Apneic threshold was found to play a major role in ventilatory responses to spontaneous sighs. Sighs led to apneic pauses followed by periods of periodic breathing with peripheral chemoreceptor CO2 gain, cardiac output, and lung volume were at reported normal levels. Apneic threshold when exceeded was observed to cause an asymmetry in the periodic breathing cycling and an increased periodic breathing frequency. Sighs in infants occur frequently enough to lead to repeated stimulation within the epoch duration of periodic breathing for a single sigh. Multiple sighs may then play a major role in promoting continuous periodic breathing in infants. Peripheral chemoreceptor gain estimated using endogenous CO2 led to validated predicted periodic breathing cycle duration as a function of age. Brain vascular volume increase with CO2 contributes to periodic breathing in very young (1-2 day old) preterm infants.
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Affiliation(s)
- Stanley M. Yamashiro
- Biomedical Engineering DepartmentUniversity of Southern CaliforniaLos AngelesCaliforniaUSA
| | - Narayan P. Iyer
- Fetal and Neonatal Institute, Div of Neonatology, CHLA Dept of Pediatrics, Keck School of MedicineLos AngelesCaliforniaUSA
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2
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Trachsel D, Erb TO, Hammer J, von Ungern‐Sternberg BS. Developmental respiratory physiology. Paediatr Anaesth 2022; 32:108-117. [PMID: 34877744 PMCID: PMC9135024 DOI: 10.1111/pan.14362] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/02/2021] [Accepted: 12/05/2021] [Indexed: 12/25/2022]
Abstract
Various developmental aspects of respiratory physiology put infants and young children at an increased risk of respiratory failure, which is associated with a higher rate of critical incidents during anesthesia. The immaturity of control of breathing in infants is reflected by prolonged central apneas and periodic breathing, and an increased risk of apneas after anesthesia. The physiology of the pediatric upper and lower airways is characterized by a higher flow resistance and airway collapsibility. The increased chest wall compliance and reduced gas exchange surface of the lungs reduce the pulmonary oxygen reserve vis-à-vis a higher metabolic oxygen demand, which causes more rapid oxygen desaturation when ventilation is compromised. This review describes the various developmental aspects of respiratory physiology and summarizes anesthetic implications.
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Affiliation(s)
- Daniel Trachsel
- Pediatric Intensive Care and PulmonologyUniversity Children’s Hospital of Basel UKBBBaselSwitzerland
| | - Thomas O. Erb
- Department AnesthesiologyUniversity Children’s Hospital of Basel UKBBBaselSwitzerland
| | - Jürg Hammer
- Pediatric Intensive Care and PulmonologyUniversity Children’s Hospital of Basel UKBBBaselSwitzerland
| | - Britta S. von Ungern‐Sternberg
- Department of Anaesthesia and Pain ManagementPerth Children’s HospitalPerthWAAustralia,Division of Emergency Medicine, Anaesthesia and Pain MedicineMedical SchoolThe University of Western AustraliaPerthWAAustralia,Perioperative Medicine TeamTelethon Kids InstitutePerthWAAustralia
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3
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Mammel D, Kemp J. Prematurity, the diagnosis of bronchopulmonary dysplasia, and maturation of ventilatory control. Pediatr Pulmonol 2021; 56:3533-3545. [PMID: 34042316 DOI: 10.1002/ppul.25519] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 11/10/2022]
Abstract
Infants born before 32 weeks gestational age and receiving respiratory support at 36 weeks postmenstrual age (PMA) are diagnosed with bronchopulmonary dysplasia (BPD). This label suggests that their need for supplemental oxygen (O2 ) is primarily due to acquired dysplasia of airways and airspaces, and that the supplemental O2 is treating residual parenchymal lung disease. However, emerging evidence suggests that immature ventilatory control may also contribute to the need for supplemental O2 at 36 weeks PMA. In all newborns, maturation of ventilatory control continues ex utero and is a plastic process. Among premature infants, supplemental O2 mitigates the hypoxemic effects of delayed maturation of ventilatory control, as well as reduces the duration and frequency of periodic breathing events. Nevertheless, prematurity is associated with altered and occasionally aberrant maturation of ventilatory control. Infants born prematurely, with or without a diagnosis of BPD, are more prone to long-lasting effects of dysfunctional ventilatory control. This review addresses normal and abnormal maturation of ventilatory control and suggests how aberrant maturation complicates assigning the diagnosis of BPD. Greater awareness of the interaction between parenchymal lung disease and delayed maturation of ventilatory control is essential to understanding why a given premature infant requires and is benefitting from supplemental O2 at 36 weeks PMA.
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Affiliation(s)
- Daniel Mammel
- Department of Pediatrics, Division of Newborn Medicine, Washington University School of Medicine in Saint Louis, St. Louis, Missouri, USA
| | - James Kemp
- Department of Pediatrics, Allergy and Pulmonary Medicine, Division of Allergy, Immunology, and Pulmonary Medicine, Washington University School of Medicine in Saint Louis, St. Louis, Missouri, USA
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4
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Postnatal changes in O2 and CO2 sensitivity in rodents. Respir Physiol Neurobiol 2020; 272:103313. [DOI: 10.1016/j.resp.2019.103313] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 08/31/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023]
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5
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Sprenger RJ, Kim AB, Dzal YA, Milsom WK. Comparison of the CO2 ventilatory response through development in three rodent species: Effect of fossoriality. Respir Physiol Neurobiol 2019; 264:19-27. [DOI: 10.1016/j.resp.2019.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/27/2019] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
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6
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González-Castillo C, Muñoz-Ortiz E, Guzmán-Brambila C, Rojas-Mayorquín AE, Beltran-Parrazal L, Ortuño-Sahagún D, Morgado-Valle C. Differential Expression of Ion Channels in Adult and Neonatal Rat Ventral Respiratory Column. J Mol Neurosci 2017; 64:51-61. [DOI: 10.1007/s12031-017-1001-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/10/2017] [Indexed: 12/14/2022]
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7
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Orr JE, Malhotra A, Sands SA. Pathogenesis of central and complex sleep apnoea. Respirology 2016; 22:43-52. [PMID: 27797160 DOI: 10.1111/resp.12927] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/22/2016] [Accepted: 10/03/2016] [Indexed: 12/01/2022]
Abstract
Central sleep apnoea (CSA) - the temporary absence or diminution of ventilatory effort during sleep - is seen in a variety of forms including periodic breathing in infancy and healthy adults at altitude and Cheyne-Stokes respiration in heart failure. In most circumstances, the cyclic absence of effort is paradoxically a consequence of hypersensitive ventilatory chemoreflex responses to oppose changes in airflow, that is elevated loop gain, leading to overshoot/undershoot ventilatory oscillations. Considerable evidence illustrates overlap between CSA and obstructive sleep apnoea (OSA), including elevated loop gain in patients with OSA and the presence of pharyngeal narrowing during central apnoeas. Indeed, treatment of OSA, whether via continuous positive airway pressure (CPAP), tracheostomy or oral appliances, can reveal CSA, an occurrence referred to as complex sleep apnoea. Factors influencing loop gain include increased chemosensitivity (increased controller gain), reduced damping of blood gas levels (increased plant gain) and increased lung to chemoreceptor circulatory delay. Sleep-wake transitions and pharyngeal dilator muscle responses effectively raise the controller gain and therefore also contribute to total loop gain and overall instability. In some circumstances, for example apnoea of infancy and central congenital hypoventilation syndrome, central apnoeas are the consequence of ventilatory depression and defective ventilatory responses, that is low loop gain. The efficacy of available treatments for CSA can be explained in terms of their effects on loop gain, for example CPAP improves lung volume (plant gain), stimulants reduce the alveolar-inspired PCO2 difference and supplemental oxygen lowers chemosensitivity. Understanding the magnitude of loop gain and the mechanisms contributing to instability may facilitate personalized interventions for CSA.
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Affiliation(s)
- Jeremy E Orr
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, La Jolla, California, USA
| | - Atul Malhotra
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, La Jolla, California, USA
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.,Department of Allergy Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, Melbourne, Victoria, Australia
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McDonald FB, Chandrasekharan K, Wilson RJA, Hasan SU. Cardiorespiratory control and cytokine profile in response to heat stress, hypoxia, and lipopolysaccharide (LPS) exposure during early neonatal period. Physiol Rep 2016; 4:4/2/e12688. [PMID: 26811056 PMCID: PMC4760388 DOI: 10.14814/phy2.12688] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Sudden infant death syndrome (SIDS) is one of the most common causes of postneonatal infant mortality in the developed world. An insufficient cardiorespiratory response to multiple environmental stressors (such as prone sleeping positioning, overwrapping, and infection), during a critical period of development in a vulnerable infant, may result in SIDS. However, the effect of multiple risk factors on cardiorespiratory responses has rarely been tested experimentally. Therefore, this study aimed to quantify the independent and possible interactive effects of infection, hyperthermia, and hypoxia on cardiorespiratory control in rats during the neonatal period. We hypothesized that lipopolysaccharide (LPS) administration will negatively impact cardiorespiratory responses to increased ambient temperature and hypoxia in neonatal rats. Sprague-Dawley neonatal rat pups were studied at postnatal day 6-8. Rats were examined at an ambient temperature of 33°C or 38°C. Within each group, rats were allocated to control, saline, or LPS (200 μg/kg) treatments. Cardiorespiratory and thermal responses were recorded and analyzed before, during, and after a hypoxic exposure (10% O2). Serum samples were taken at the end of each experiment to measure cytokine concentrations. LPS significantly increased cytokine concentrations (such as TNFα, IL-1β, MCP-1, and IL-10) compared to control. Our results do not support a three-way interaction between experimental factors on cardiorespiratory control. However, independently, heat stress decreased minute ventilation during normoxia and increased the hypoxic ventilatory response. Furthermore, LPS decreased hypoxia-induced tachycardia. Herein, we provide an extensive serum cytokine profile under various experimental conditions and new evidence that neonatal cardiorespiratory responses are adversely affected by dual interactions of environmental stress factors.
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Affiliation(s)
- Fiona B McDonald
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute & Alberta Children's Hospital Research Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Kumaran Chandrasekharan
- Fetal and Neonatal Physiology, Department of Pediatrics, Faculty of Medicine B271, Health Sciences Center, University of Calgary, Calgary, Alberta, Canada
| | - Richard J A Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute & Alberta Children's Hospital Research Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Shabih U Hasan
- Fetal and Neonatal Physiology, Department of Pediatrics, Faculty of Medicine B271, Health Sciences Center, University of Calgary, Calgary, Alberta, Canada
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A newborn tolerated severe hypercapnia during general anesthesia: a case report. J Med Case Rep 2015; 9:196. [PMID: 26364835 PMCID: PMC4568571 DOI: 10.1186/s13256-015-0685-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2015] [Accepted: 08/20/2015] [Indexed: 11/12/2022] Open
Abstract
Introduction Severe hypercapnia is a rare but harmful complication of general anesthesia. We report the case of a newborn who developed severe hypercapnia with unknown reasons during general anesthesia but recovered well. This report will advance our understanding about the causes of severe hypercapnia during anesthesia, the possible compensatory mechanisms and the characteristics of neonatal respiratory physiology and intracellular buffering systems. Case presentation A 21-day-old Chinese baby girl who had an incarcerated hernia received an emergent exploratory operation under general anesthesia. She developed severe hypercapnia during surgery for unclear reasons. Arterial blood gas revealed a PCO2 of 149mmHg. Troubleshooting and relevant measures were taken, but the level of CO2 did not decrease. In spite of the high level of PCO2, the newborn recovered well without any complications. Conclusions Neonates are vulnerable to hypercapnia during anesthesia for their characteristic respiratory physiology. Heat and moisture exchange should be used with caution in newborns under general anesthesia as it can increase dead space. Intracellular buffering systems play an important role in tolerating severe hypercapnia. Although this case raised a great challenge to the homeostatic mechanism of the body, measures should be taken to maintain PCO2 values around the clinically acceptable level.
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Abstract
Breathing movements have been demonstrated in the fetuses of every mammalian species investigated and are a critical component of normal fetal development. The classic sheep preparations instrumented for chronic fetal monitoring determined that fetal breathing movements (FBMs) occur in aggregates interspersed with long periods of quiescence that are strongly associated with neurophysiological state. The fetal sheep model also provided data regarding the neurochemical modulation of behavioral state and FBMs under a variety of in utero conditions. Subsequently, in vitro rodent models have been developed to advance our understanding of cellular, synaptic, network, and more detailed neuropharmacological aspects of perinatal respiratory neural control. This includes the ontogeny of the inspiratory rhythm generating center, the preBötzinger complex (preBötC), and the anatomical and functional development of phrenic motoneurons (PMNs) and diaphragm during the perinatal period. A variety of newborn animal models and studies of human infants have provided insights into age-dependent changes in state-dependent respiratory control, responses to hypoxia/hypercapnia and respiratory pathologies.
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Affiliation(s)
- John J Greer
- Department of Physiology, Centre for Neuroscience, Women and Children Health Research Institute, University of Alberta, Edmonton, Alberta, Canada.
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11
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MacLean JE, Tan S, Fitzgerald DA, Waters KA. Assessing ventilatory control in infants at high risk of sleep disordered breathing: a study of infants with cleft lip and/or palate. Pediatr Pulmonol 2013; 48:265-73. [PMID: 22528960 DOI: 10.1002/ppul.22568] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 04/01/2012] [Indexed: 11/10/2022]
Abstract
Neonatal exposure to intermittent hypoxia results in altered ventilatory response to subsequent hypoxia in animal models. The effect of similar exposure in human infants is unknown. Our objective was to determine the impact of sleep disordered breathing (SDB) in early infancy on ventilatory response in infants. We recruited consecutive infants with cleft lip and/or palate (CL/P) to undergo ventilatory response testing using exposure to a hypoxic (15% O(2) ) gas mixture during sleep. This population is at high risk of SDB because of smaller airway caliber and abnormal palatal muscle attachments predisposing them to airway obstruction of ranging severity from birth. Ventilatory responses were compared between infants with a low apnea-hypopnea index (AHI; AHI < 15 events/hr) and a high AHI (AHI ≥ 15 events/hr). Testing was successfully completed in 22 of 23 infants who underwent testing at 4.4 ± 4.8 months. Infants with high AHI had lower weight z-scores, higher number of oxygen desaturation events during sleep, but similar oxygen saturation (S(p) O(2) ) nadir compared to infants with low AHI. The pattern of ventilatory response to hypoxia differed between the two groups; infants with high AHI had an earlier ventilatory decline and a blunted maximal ventilatory response to hypoxia. Infants with a high AHI use a different strategy to augment ventilation in response to hypoxia; while infants with a low AHI initially increased respiratory rate, tidal volume was the first parameter to increase in infants with high AHI. These results demonstrate that SDB in infancy is associated with altered ventilatory response to hypoxia.
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Affiliation(s)
- Joanna E MacLean
- Division of Respiratory Medicine, Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
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12
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Taylor BE, Brundage CM. Chronic, but not acute, ethanol exposure impairs central hypercapnic ventilatory drive in bullfrog tadpoles. Respir Physiol Neurobiol 2013; 185:533-42. [DOI: 10.1016/j.resp.2012.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 10/29/2012] [Accepted: 11/12/2012] [Indexed: 11/25/2022]
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13
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Abstract
Experimental and clinical data indicate that ventilator strategies with permissive hypercapnia may reduce lung injury by a variety of mechanisms. Seven randomized controlled trials in preterm neonates suggest that permissive hypercapnia started early, before the initiation of mechanical ventilation (in conjunction with continuous positive airway pressure), followed by prolonged permissive hypercapnia if mechanical ventilation is needed is an alternative to early ventilation and surfactant. Permissive hypercapnia may improve pulmonary outcomes and survival.
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Affiliation(s)
- Julie Ryu
- Department of Pediatrics, Rady Children's Hospital, University of California San Diego, 9500 Gilman Drive, MC 0735, La Jolla, CA 92093, USA
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14
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Edwards BA, Sands SA, Berger PJ. Postnatal maturation of breathing stability and loop gain: the role of carotid chemoreceptor development. Respir Physiol Neurobiol 2012; 185:144-55. [PMID: 22705011 DOI: 10.1016/j.resp.2012.06.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/16/2012] [Accepted: 06/01/2012] [Indexed: 11/17/2022]
Abstract
Any general model of respiratory control must explain a puzzling array of breathing patterns that are observed during the course of a lifetime. Particular challenges are to understand why periodic breathing is rarely seen in the first few days after birth, reaches a peak at 2-4 weeks postnatal age, and disappears by 6 months, why it is prevalent in preterm infants, and why it reappears in adults at altitude or with heart failure. In this review we use the concept of loop gain to obtain quantitative insight into the genesis of unstable breathing patterns with a particular focus on how changes in carotid body function could underlie the age-related dependence of periodic breathing.
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Affiliation(s)
- Bradley A Edwards
- Division of Sleep Medicine, Brigham and Women's Hospital & Harvard Medical School, Boston, MA, USA.
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15
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Abstract
Most abnormalities of ventilatory control in infants are due to immaturity or abnormal development of ventilatory control. This includes a broad range, from rare disorders like congenital central hypoventilation syndrome to common problems such as apnoea of prematurity. Development of the ventilatory control system, including central respiratory rhythmogenesis and central and peripheral chemoreception, begins early in gestation and continues for weeks or months after birth. Development of the neural components of central rhythmogenesis and their highly complex interconnectivity results from complex, timing-sensitive interactions between patterning and other genes, transcription factors and neurotrophic factors. At birth, nearly all aspects of ventilatory control remain immature, especially in preterm infants; and postnatal maturation can be altered by hypoxia, toxins and other stressors. Clinical care may be greatly enhanced by increased awareness of ventilatory control maturation and related disorders.
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Affiliation(s)
- John L Carroll
- University of Arkansas for Medical Sciences, Department of Pediatrics, Division of Pulmonary Medicine, Arkansas Children's Hospital, Little Rock, Arkansas 72212, USA.
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16
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Teppema LJ, Dahan A. The Ventilatory Response to Hypoxia in Mammals: Mechanisms, Measurement, and Analysis. Physiol Rev 2010; 90:675-754. [DOI: 10.1152/physrev.00012.2009] [Citation(s) in RCA: 257] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The respiratory response to hypoxia in mammals develops from an inhibition of breathing movements in utero into a sustained increase in ventilation in the adult. This ventilatory response to hypoxia (HVR) in mammals is the subject of this review. The period immediately after birth contains a critical time window in which environmental factors can cause long-term changes in the structural and functional properties of the respiratory system, resulting in an altered HVR phenotype. Both neonatal chronic and chronic intermittent hypoxia, but also chronic hyperoxia, can induce such plastic changes, the nature of which depends on the time pattern and duration of the exposure (acute or chronic, episodic or not, etc.). At adult age, exposure to chronic hypoxic paradigms induces adjustments in the HVR that seem reversible when the respiratory system is fully matured. These changes are orchestrated by transcription factors of which hypoxia-inducible factor 1 has been identified as the master regulator. We discuss the mechanisms underlying the HVR and its adaptations to chronic changes in ambient oxygen concentration, with emphasis on the carotid bodies that contain oxygen sensors and initiate the response, and on the contribution of central neurotransmitters and brain stem regions. We also briefly summarize the techniques used in small animals and in humans to measure the HVR and discuss the specific difficulties encountered in its measurement and analysis.
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Affiliation(s)
- Luc J. Teppema
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Albert Dahan
- Department of Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands
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Edwards BA, Sands SA, Skuza EM, Brodecky V, Stockx EM, Wilkinson MH, Berger PJ. Maturation of respiratory control and the propensity for breathing instability in a sheep model. J Appl Physiol (1985) 2009; 107:1463-71. [DOI: 10.1152/japplphysiol.00587.2009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Limited evidence suggests that the ventilatory interaction between O2 and CO2 is additive after birth and becomes multiplicative with postnatal development. Such a switch may be linked to the propensity for periodic breathing (PB) in infancy. To test this idea, we characterized the maturation of the respiratory controller and its effect on breathing stability in ∼10-day-old lambs and 6-mo-old sheep. We measured 1) carotid body sensitivity via dynamic ventilatory responses to step changes in O2 and CO2, 2) steady-state ventilatory sensitivity to CO2 under hypoxic and hyperoxic conditions, 3) the dependence of the apneic threshold on arterial Po2, and 4) the effect of hypoxic or hypercapnic gas inhalation during induced PB. Stability of the system was assessed using surrogate measures of loop gain. Peripheral sensitivity to O2 was higher in newborn than in older animals ( P < 0.05), but peripheral CO2 sensitivity was unchanged. Central CO2 sensitivity was reduced with age, but the slopes of the ventilatory responses to CO2 were the same in hypoxia and hyperoxia. Reduced arterial Po2 caused a leftward shift in the apneic threshold at both ages. Inspiration of hypoxic gas during PB immediately halted PB, whereas hypercapnia stopped PB only after one or two further PB cycles. We conclude that the controller in the sheep remains additive over the first 6 mo of life. Our results also show that the loop gain of the respiratory control system is reduced with age, possibly as a result of a reduction of peripheral O2 sensitivity.
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Affiliation(s)
- Bradley A. Edwards
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
| | - Scott A. Sands
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
| | - Elizabeth M. Skuza
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
| | - Vojta Brodecky
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
| | - Elaine M. Stockx
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
| | - Malcolm H. Wilkinson
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
| | - Philip J. Berger
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Monash Medical Centre, Clayton, Australia
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18
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Increased peripheral chemosensitivity via dopaminergic manipulation promotes respiratory instability in lambs. Respir Physiol Neurobiol 2008; 164:419-28. [DOI: 10.1016/j.resp.2008.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/03/2008] [Accepted: 09/03/2008] [Indexed: 12/20/2022]
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Hibbs AM, Johnson NL, Rosen CL, Kirchner HL, Martin R, Storfer-Isser A, Redline S. Prenatal and neonatal risk factors for sleep disordered breathing in school-aged children born preterm. J Pediatr 2008; 153:176-82. [PMID: 18534222 PMCID: PMC2753386 DOI: 10.1016/j.jpeds.2008.01.040] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 11/09/2007] [Accepted: 01/30/2008] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Previously published data from the Cleveland Children's Sleep and Health Study demonstrated that preterm infants are especially vulnerable both to sleep disordered breathing (SDB) and its neurocognitive sequelae at age 8 to 11 years. In this analysis, we aimed to identify the components of the neonatal medical history associated with childhood SDB among children born prematurely. STUDY DESIGN This analysis focuses on the 383 children in the population-based cohort from the Cleveland Children's Sleep and Health Study who were born <37 weeks gestational age and who had technically acceptable sleep studies performed at ages 8 to 11 years (92% of all preterm children). Logistic regression was used to evaluate the associations between candidate perinatal and neonatal risk factors and the presence of childhood SDB by sleep study. RESULTS Twenty-eight preterm children (7.3%) met the definition for SDB at age 8 to 11 years. Having a single mother and mild maternal preeclampsia were strongly associated with SDB in unadjusted and race-adjusted models. Unadjusted analyses also identified xanthine use and cardiopulmonary resuscitation or intubation in the delivery room as potential risk-factors for SDB. We did not find a significant link between traditional markers of severity of neonatal illness-such as gestational age, birth weight, intraventricular hemorrhage, bronchopulmonary dysplasia, or duration of ventilation-and childhood SDB at school age. CONCLUSIONS These results represent a first step in identifying prenatal and neonatal characteristics that place preterm infants at higher risk for childhood SDB. The strong association between mild preeclampsia and childhood SDB underscores the importance of research aimed at understanding in utero risk factors for neurorespiratory development.
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Affiliation(s)
- Anna Maria Hibbs
- Department of Pediatrics, Rainbow Babies and Children's Hospital, Case Western Reserve University, Cleveland, OH 44106-6010, USA.
| | - Nathan L Johnson
- Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Danville, PA
| | - Carol L Rosen
- Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Danville, PA
| | - H Lester Kirchner
- Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Danville, PA.,Geisinger Center for Health Research, Danville, PA
| | - Richard Martin
- Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Danville, PA
| | - Amy Storfer-Isser
- Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Danville, PA
| | - Susan Redline
- Department of Pediatrics, Rainbow Babies and Children’s Hospital, Case Western Reserve University, Danville, PA
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Wilkinson MH, Skuza EM, Rennie GC, Sands SA, Yiallourou SR, Horne RSC, Berger PJ. Postnatal development of periodic breathing cycle duration in term and preterm infants. Pediatr Res 2007; 62:331-6. [PMID: 17622961 DOI: 10.1203/pdr.0b013e3180db29e5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Previous studies of the maturation of periodic breathing cycle duration (PCD) with postnatal age in infants have yielded conflicting results. PCD is reported to fall in term infants over the first 6 mo postnatally, whereas in preterm infants PCD is reported either not to change or to fall. Contrary to measured values, use of a theoretical respiratory control model predicts PCD should increase with postnatal age. We re-examined this issue in a longitudinal study of 17 term and 22 preterm infants. PCD decreased exponentially from birth in both groups, reaching a plateau between 4 and 6 mo of age. In preterm infants, PCD fell from a mean of 18.3 s to 9.8 s [95% confidence interval (CI) is +/- 3.2 s]. In term infants, PCD fell from 15.4 s to 10.1 s (95% CI is +/- 3.1 s). The higher PCD at birth in preterm infants, and the similar PCD value at 6 mo in the two groups, suggest a more rapid maturation of PCD in preterm infants. This study confirms that PCD declines after birth. The disagreement between our data and theoretical predictions of PCD may point to important differences between the respiratory controller of the infant and adult.
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Affiliation(s)
- Malcolm H Wilkinson
- Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash University, Clayton, Victoria, 3168, Australia.
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Xu F, Zhuang J, Wang R, Seagrave JC, March TH. Blunted ventilatory response to hypoxia/hypercapnia in mice with cigarette smoke-induced emphysema. Respir Physiol Neurobiol 2007; 158:5-13. [PMID: 17531548 PMCID: PMC2703296 DOI: 10.1016/j.resp.2007.04.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/05/2007] [Accepted: 04/05/2007] [Indexed: 11/25/2022]
Abstract
It has been reported that the degree of emphysema induced by chronic cigarette smoke (CS) is greater in female C3H/HeN mice as compared to other mouse strains. We hypothesized that these mice would develop the similar major characteristics seen in hypercapnic patients with chronic obstructive pulmonary disease (COPD), including emphysema, pulmonary inflammation, hypercapnia/hypoxemia, rapid breathing, and attenuated ventilatory response (AVR). Mice were exposed either to CS or filtered air (FA) for 16 weeks. After exposure, arterial blood gases and minute ventilation were measured before and during chemical challenges in anesthetized and spontaneously breathing mice. We found that as compared to FA, CS exposure caused emphysema and pulmonary inflammation associated with: (1) hypercapnia and hypoxemia, (2) rapid breathing, and (3) AVR to 25 breaths of pure N(2), 5% CO(2) alone, and 5% CO(2) coupled with 10% O(2). The similarity of these pathophysiological characteristics between our mouse model and COPD patients suggests that this model could be effectively applied to study COPD pathophysiology, especially central mechanisms of the AVR genesis.
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Affiliation(s)
- F Xu
- Pathophysiology Program, Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM 87108, USA.
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Davis SE, Solhied G, Castillo M, Dwinell M, Brozoski D, Forster HV. Postnatal developmental changes in CO2 sensitivity in rats. J Appl Physiol (1985) 2006; 101:1097-103. [PMID: 16794027 DOI: 10.1152/japplphysiol.00378.2006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ventilatory sensitivity to CO2 in awake adult Brown Norway (BN) rats is 50–75% lower than in adult Sprague-Dawley (SD) and salt-sensitive Dahl S (SS) rats. The purpose of the present study was to test the hypothesis that this difference would be apparent during the development of CO2 sensitivity. Four litters of each strain were divided into four groups such that rats were exposed to 7% inspired CO2 for 5 min in a plethysmograph every third day from postnatal day (P) 0 to P21 and again on P29 and P30. From P0 to P14, CO2 exposure increased pulmonary ventilation (V̇e) by 25–50% in the BN and SD strains and between 25 to over 200% in the SS strain. In all strains beginning around P15, the response to CO2 increased progressively reaching a peak at P19–21 when V̇e during hypercapnia was 175–225% above eucapnia. There were minimal changes in CO2 sensitivity between P21 and P30, and at both ages there were minimal between-strain differences. At P30, the response to CO2 in the SS and SD strains was near the adult response, but the response in the BN rats was 100% greater at P30 than in adults. We conclude that 1) CO2-sensing mechanisms, and/or mechanisms downstream from the chemoreceptors, change dramatically at the age in rats when other physiological systems are also maturing (∼P15), and 2) there is a high degree of age-dependent plasticity in CO2 sensitivity in rats, which differs between strains.
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Affiliation(s)
- S E Davis
- Department of Physiology, Medical College of Wisconsin and Zablocki Veterans Affairs Medical Center, Milwaukee, USA
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Baldwin DN, Pillow JJ, Stocks J, Frey U. Lung-function tests in neonates and infants with chronic lung disease: tidal breathing and respiratory control. Pediatr Pulmonol 2006; 41:391-419. [PMID: 16555264 DOI: 10.1002/ppul.20400] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This paper is the fourth in a series of reviews that will summarize available data and critically discuss the potential role of lung-function testing in infants with acute neonatal respiratory disorders and chronic lung disease of infancy. The current paper addresses information derived from tidal breathing measurements within the framework outlined in the introductory paper of this series, with particular reference to how these measurements inform on control of breathing. Infants with acute and chronic respiratory illness demonstrate differences in tidal breathing and its control that are of clinical consequence and can be measured objectively. The increased incidence of significant apnea in preterm infants and infants with chronic lung disease, together with the reportedly increased risk of sudden unexplained death within the latter group, suggests that control of breathing is affected by both maturation and disease. Clinical observations are supported by formal comparison of tidal breathing parameters and control of breathing indices in the research setting.
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Affiliation(s)
- David N Baldwin
- Centre for Child Health Research and Telethon Institute for Child Health Research, University of Western Australia, Perth, Western Australia, Australia.
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Putnam RW, Conrad SC, Gdovin MJ, Erlichman JS, Leiter JC. Neonatal maturation of the hypercapnic ventilatory response and central neural CO2 chemosensitivity. Respir Physiol Neurobiol 2005; 149:165-79. [PMID: 15876557 PMCID: PMC1255969 DOI: 10.1016/j.resp.2005.03.004] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2005] [Revised: 03/22/2005] [Accepted: 03/24/2005] [Indexed: 11/16/2022]
Abstract
The ventilatory response to CO2 changes as a function of neonatal development. In rats, a ventilatory response to CO2 is present in the first 5 days of life, but this ventilatory response to CO2 wanes and reaches its lowest point around postnatal day 8. Subsequently, the ventilatory response to CO2 rises towards adult levels. Similar patterns in the ventilatory response to CO2 are seen in some other species, although some animals do not exhibit all of these phases. Different developmental patterns of the ventilatory response to CO2 may be related to the state of development of the animal at birth. The triphasic pattern of responsiveness (early decline, a nadir, and subsequent achievement of adult levels of responsiveness) may arise from the development of several processes, including central neural mechanisms, gas exchange, the neuromuscular junction, respiratory muscles and respiratory mechanics. We only discuss central neural mechanisms here, including altered CO2 sensitivity of neurons among the various sites of central CO2 chemosensitivity, changes in astrocytic function during development, the maturation of electrical and chemical synaptic mechanisms (both inhibitory and excitatory mechanisms) or changes in the integration of chemosensory information originating from peripheral and multiple central CO2 chemosensory sites. Among these central processes, the maturation of synaptic mechanisms seems most important and the relative maturation of synaptic processes may also determine how plastic the response to CO2 is at any particular age.
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Affiliation(s)
- Robert W Putnam
- Department of Anatomy and Physiology, Wright State University School of Medicine, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA.
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Gaultier C, Gallego J. Development of respiratory control: Evolving concepts and perspectives. Respir Physiol Neurobiol 2005; 149:3-15. [PMID: 15941676 DOI: 10.1016/j.resp.2005.04.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 04/22/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
The mechanisms underlying respiratory system immaturity in newborns have been investigated, both in vivo and in vitro, in humans and in animals. Immaturity affects breathing rhythmicity and its modulation by suprapontine influences and by afferents from central and peripheral chemoreceptors. Recent research has moved from bedside tools to sophisticated technologies, bringing new insights into the plasticity and genetics of respiratory control development. Genetic research has benefited from investigations of newborn mice having targeted deletions of genes involved in respiratory control. Genetic variability may govern the normal programming of development and the processes underlying adaptation to homeostasis disturbances induced by prenatal and postnatal insults. Studies of plasticity have emphasized the role of neurotrophic factors. Improvements in our understanding of the mechanistic effects of these factors should lead to new neuroprotective strategies for infants at risk for early respiratory control disturbances, such as apnoeas of prematurity, sudden infant death syndrome and congenital central hypoventilation syndrome.
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Affiliation(s)
- Claude Gaultier
- Service de Physiologie, Hôpital Robert Debré, 48 Boulevard Serurier, 75019 Paris, France.
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Cohen G, Katz-Salamon M. Development of chemoreceptor responses in infants. Respir Physiol Neurobiol 2005; 149:233-42. [PMID: 16203216 DOI: 10.1016/j.resp.2005.02.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2004] [Revised: 02/15/2005] [Accepted: 02/17/2005] [Indexed: 11/26/2022]
Abstract
This paper is devoted to the field of chemoreception and its role in the control of breathing in infants. We use "chemoreception" to refer to the capacity to sense and process changes in P(O2) and P(CO2), and also to react to these changes by adjusting ventilation in order to maintain homeostasis. Functional chemoreceptors are not essential to commence or even to sustain breathing efforts immediately at or after birth; the intense brain activation, which occurs at birth, is sufficient. Over subsequent days to weeks, however, this "neurogenic" drive weakens and drive from the chemoreceptors becomes critical for generating and maintaining a normal breathing rhythm. Failure of the chemoreceptors to develop normally, consequently, becomes an important underlying cause of breathing dysfunction, particularly during sleep. The paper deals with the methods available to study chemoreception in newborn infants and provide an overview of the early postnatal changes and interactions, which influence breathing at rest and under stress. The latter may be described in terms of the threshold and strength as well as the delay/speed with which ventilation changes in response to chemical stimulation. We conclude with a survey of disorders associated with chemoreceptor deficits in infancy.
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Affiliation(s)
- Gary Cohen
- Department of Woman and Child Health, Neonatal Unit, Karolinska Institute, Stockholm, Sweden
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Abstract
PURPOSE OF REVIEW Respiratory control disorders such as apnea of prematurity, apparent life-threatening events, sudden infant death syndrome, and central hypoventilation are relatively frequent conditions in the pediatric age range and are associated with substantial morbidity and mortality. The explosion of technological breakthroughs in biology and medicine has facilitated our understanding of the fundamental mechanisms that govern the development of brain regions underlying respiratory control functions. RECENT FINDINGS Recent critically important discoveries encompass the identification of neurons that constitute the central respiratory rhythm generator in the brainstem, the conceptual framework allowing for many neurons located in multiple strategic regions within the brain to coordinate central chemosensitivity, the discovery of long-term and short-term plasticity in hypoxic ventilatory regulation, and the recent uncovering of specific gene mutations in children affected with congenital central hypoventilation syndrome. SUMMARY While the developmental aspects of control breathing are only now being actively explored in the context of our current understanding, it is likely that such efforts will yield important novel approaches to the clinical and pharmacologic management of these disorders in the near future.
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Affiliation(s)
- David Gozal
- Kosair Children's Hospital Research Institute, and Department of Pediatrics, University of Louisville, Kentucky 40202, USA.
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