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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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Ali K, Rosser T, Bhat R, Wolff K, Hannam S, Rafferty GF, Greenough A. Antenatal smoking and substance-misuse, infant and newborn response to hypoxia. Pediatr Pulmonol 2017; 52:650-655. [PMID: 27723956 DOI: 10.1002/ppul.23620] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 11/10/2022]
Abstract
OBJECTIVES To determine at the peak age for sudden infant death syndrome (SIDS) the ventilatory response to hypoxia of infants whose mothers substance misused in pregnancy (SM infants), or smoked during pregnancy (S mothers) and controls whose mothers neither substance misused or smoked. In addition, we compared the ventilatory response to hypoxia during the neonatal period and peak age of SIDS. WORKING HYPOTHESIS Infants of S or SM mothers compared to control infants would have a poorer ventilatory response to hypoxia at the peak age of SIDS. STUDY DESIGN Prospective, observational study. PATIENT-SUBJECT SELECTION Twelve S; 12 SM and 11 control infants were assessed at 6-12 weeks of age and in the neonatal period. METHODOLOGY Changes in minute volume, oxygen saturation, heart rate, and end tidal carbon dioxide levels on switching from breathing room air to 15% oxygen were assessed. Maternal and infant urine samples were tested for cotinine, cannabinoids, opiates, amphetamines, methadone, cocaine, and benzodiazepines. RESULTS The S and SM infants had a greater decline in minute volume (P = 0.037, P = 0.016, respectively) and oxygen saturation (P = 0.031) compared to controls. In all groups, the magnitude of decline in minute volume in response to hypoxia was higher in the neonatal period compared to at 6-12 weeks (P < 0.001). CONCLUSIONS Both maternal substance misuse and smoking were associated with an impaired response to a hypoxic challenge at the peak age for SIDS. The hypoxic ventilatory decline was more marked in the neonatal period compared to the peak age for SIDS indicating a maturational effect. Pediatr Pulmonol. 2017;52:650-655. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Kamal Ali
- Neonatal Intensive Care Unit, King's College Hospital NHS Foundation Trust, London, United Kingdom
| | - Thomas Rosser
- Division of Asthma, Allergy and Lung Biology, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, United Kingdom
| | - Ravindra Bhat
- Neonatal Intensive Care Unit, King's College Hospital NHS Foundation Trust, London, United Kingdom
| | - Kim Wolff
- Addiction Sciences Unit, King's College London, London, United Kingdom
| | - Simon Hannam
- Division of Asthma, Allergy and Lung Biology, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, United Kingdom
| | - Gerrard F Rafferty
- Division of Asthma, Allergy and Lung Biology, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, United Kingdom
| | - Anne Greenough
- Neonatal Intensive Care Unit, King's College Hospital NHS Foundation Trust, London, United Kingdom.,Division of Asthma, Allergy and Lung Biology, MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, King's College London, London, United Kingdom.,National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London, London, United Kingdom
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DeHaan KL, Seton C, Fitzgerald DA, Waters KA, MacLean JE. Polysomnography for the diagnosis of sleep disordered breathing in children under 2 years of age. Pediatr Pulmonol 2015; 50:1346-53. [PMID: 25777054 PMCID: PMC6680200 DOI: 10.1002/ppul.23169] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 01/03/2015] [Accepted: 01/21/2015] [Indexed: 11/09/2022]
Abstract
OBJECTIVES To describe clinical polysomnography (PSG) results, sleep physicians' diagnosis, and treatment of sleep disorder breathing in children less than 2 years of age. STUDY DESIGN Retrospective clinical chart review at a pediatric tertiary care center, pediatric sleep laboratory. SUBJECT SELECTION Children less than 2 years of age who underwent clinical PSG over a 3-year period. METHODOLOGY PSG results and physician interpretations were identified for inclusions. Children were excluded if either PSG results or physician interpretations were unavailable for review. Infants were classified in three age groups for comparison: <6 months, 6-12 months, and >12 months. RESULTS Matched records were available for 233 PSGs undertaken at a mean age 11.1 ± 7.0 months; 31% were <6 months, 23% were 6-12 months, and 46% were 12-24 months of age. Infants <6 months showed significant differences on sleep parameters and respiratory indicators compared to other groups. Compared to physician sleep disordered breathing (SDB) classification, current pediatric apnea-hypopnea index (AHI)-based SDB severity classification overestimated SDB severity. Age and obstructive-mixed AHI (OMAHI) were most closely associated with physician identification of SDB. CONCLUSION Children <6 months of age appear to represent a distinct group with respect to PSG. Experienced sleep physicians appear to incorporate age and respiratory event frequently when determining the presence of SDB. Further information about clinical significance of apnea in infancy is required, assisted by identification of factors that sleep physicians use to identify SDB in children <6 months of age.
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Affiliation(s)
- Kristie L DeHaan
- Department of Paediatrics, Division of Respiratory Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Chris Seton
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Dominic A Fitzgerald
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.,Discipline of Paediatrics and Child Health, University of Sydney, Sydney, New South Wales, Australia
| | - Karen A Waters
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.,Discipline of Paediatrics and Child Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Physiology, University of Sydney, Sydney, New South Wales, Australia
| | - Joanna E MacLean
- Department of Paediatrics, Division of Respiratory Medicine, University of Alberta, Edmonton, Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, Alberta, Canada
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MacLean JE, Fitzgerald DA, Waters KA. Developmental changes in sleep and breathing across infancy and childhood. Paediatr Respir Rev 2015; 16:276-84. [PMID: 26364005 DOI: 10.1016/j.prrv.2015.08.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 08/06/2015] [Indexed: 11/24/2022]
Abstract
Sleep and breathing are physiological processes that begin in utero and undergo progressive change. While the major period of change for both sleep and breathing occurs during the months after birth, considered a period of vulnerability, more subtle changes continue to occur throughout childhood. The systems that control sleep and breathing develop separately, but sleep represents an activity state during which breathing and breathing control is significantly altered. Infants and young children may spend up to 12 hours a day sleeping; therefore, the effects of sleep on breathing are fundamental to understanding both processes in childhood. This review summarizes the current literature relevant to understanding the normal development of sleep and breathing across infancy and childhood.
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Affiliation(s)
- Joanna E MacLean
- Division of Respiratory Medicine, Department of Pediatrics, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada; Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia.
| | - Dominic A Fitzgerald
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Karen A Waters
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Australia; Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia
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Abstract
During the first year of life and particularly the first 6 months autonomic control of the cardio-respiratory system is still undergoing maturation and infants are at risk of cardio-respiratory instability. These instabilities are most marked during sleep, which is important as infants spend the majority of each 24 hours in sleep. Sleep state has a marked effect on the cardio-respiratory system with instabilities being more common in active sleep compared to quiet sleep. Responses to hypoxia are also immature during infancy and may make young infants more vulnerable to cardio-respiratory instability. It has been proposed that an inability to respond appropriately to a life threatening event underpins the Sudden Infant Death Syndrome (SIDS). The major risk factors for SIDS, prone sleeping and maternal smoking, both impair cardio-respiratory control in normal healthy term infants.
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Affiliation(s)
- Rosemary S C Horne
- The Ritchie Centre, Monash Institute of Medical Research, Monash University, Level 5, Monash Medical Centre, 246 Clayton Rd, Clayton, Victoria, Australia 3168.
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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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Darnall RA, Schneider RW, Tobia CM, Zemel BM. Arousal from sleep in response to intermittent hypoxia in rat pups is modulated by medullary raphe GABAergic mechanisms. Am J Physiol Regul Integr Comp Physiol 2011; 302:R551-60. [PMID: 22160541 DOI: 10.1152/ajpregu.00506.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Arousal is an important defense against hypoxia during sleep. Rat pups exhibit progressive arousal impairment (habituation) with multiple hypoxia exposures. The mechanisms are unknown. The medullary raphe (MR) is involved in autonomic functions, including sleep, and receives abundant GABAergic inputs. We hypothesized that inhibiting MR neurons with muscimol, a GABA(A) receptor agonist, or preventing GABA reuptake with nipecotic acid, would impair arousal and enhance arousal habituation and that blocking GABA(A) receptors with bicuculline would enhance arousal and attenuate habituation. Postnatal day 15 (P15) to P25 rat pups were briefly anesthetized, and microinjections with aCSF, muscimol, bicuculline, or nipecotic acid were made into the MR. After a ∼30-min recovery, pups were exposed to four 3-min episodes of hypoxia separated by 6 min of normoxia. The time to arousal from the onset of hypoxia (latency) was determined for each trial. Latency progressively increased across trials (habituation) in all groups. The overall latency was greater after muscimol and nipecotic acid compared with aCSF, bicuculline, or noninjected controls. Arousal habituation was reduced after bicuculline compared with aCSF, muscimol, nipecotic acid, or noninjected pups. Increases in latency were mirrored by decreases in chamber [O2] and oxyhemoglobin saturation. Heart rate increased during hypoxia and was greatest in muscimol-injected pups. Our results indicate that the MR plays an important, not previously described, role in arousal and arousal habituation during hypoxia and that these phenomena are modulated by GABAergic mechanisms. Arousal habituation may contribute to sudden infant death syndrome, which is associated with MR serotonergic and GABAergic receptor dysfunction.
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Affiliation(s)
- Robert A Darnall
- Department of Pediatrics, Dartmouth Medical School, Lebanon, NH 03756, USA.
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Darnall RA, McWilliams S, Schneider RW, Tobia CM. Reversible blunting of arousal from sleep in response to intermittent hypoxia in the developing rat. J Appl Physiol (1985) 2010; 109:1686-96. [PMID: 20930126 PMCID: PMC3006406 DOI: 10.1152/japplphysiol.00076.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Accepted: 10/05/2010] [Indexed: 11/22/2022] Open
Abstract
Arousal is an important survival mechanism when infants are confronted with hypoxia during sleep. Many sudden infant death syndrome (SIDS) infants are exposed to repeated episodes of hypoxia before death and have impaired arousal mechanisms. We hypothesized that repeated exposures to hypoxia would cause a progressive blunting of arousal, and that a reversal of this process would occur if the hypoxia was terminated at the time of arousal. P5 (postnatal age of 5 days), P15, and P25 rat pups were exposed to either eight trials of hypoxia (3 min 5% O(2) alternating with room air) (group A), or three hypoxia trials as in group A, followed by five trials in which hypoxia was terminated at arousal (group B). In both groups A and B, latency increased over the first four trials of hypoxia, but reversed in group B animals during trials 5-8. Progressive arousal blunting was more pronounced in the older pups. The effects of intermittent hypoxia on heart rate also depended on age. In the older pups, heart rate increased with each hypoxia exposure. In the P5 pups, however, heart rate decreased during hypoxia and did not return to baseline between exposures, resulting in a progressive fall of baseline values over successive hypoxia exposures. In the group B animals, heart rate changes during trials 1-4 also reversed during trials 5-8. We conclude that exposure to repeated episodes of hypoxia can cause progressive blunting of arousal, which is reversible by altering the exposure times to hypoxia and the period of recovery between hypoxia exposures.
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Affiliation(s)
- R A Darnall
- Department of Pediatrics, Dartmouth School of Medicine, Lebanon, New Hampshire, USA.
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Arousal response to hypoxia in newborns: Insights from animal models. Biol Psychol 2010; 84:39-45. [DOI: 10.1016/j.biopsycho.2009.12.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 11/30/2009] [Accepted: 12/02/2009] [Indexed: 11/24/2022]
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