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Kuypers K, Martherus T, Lamberska T, Dekker J, Hooper SB, Te Pas AB. Reflexes that impact spontaneous breathing of preterm infants at birth: a narrative review. Arch Dis Child Fetal Neonatal Ed 2020; 105:675-679. [PMID: 32350064 DOI: 10.1136/archdischild-2020-318915] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/17/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023]
Abstract
Some neural circuits within infants are not fully developed at birth, especially in preterm infants. Therefore, it is unclear whether reflexes that affect breathing may or may not be activated during the neonatal stabilisation at birth. Both sensory reflexes (eg, tactile stimulation) and non-invasive ventilation (NIV) can promote spontaneous breathing at birth, but the application of NIV can also compromise breathing by inducing facial reflexes that inhibit spontaneous breathing. Applying an interface could provoke the trigeminocardiac reflex (TCR) by stimulating the trigeminal nerve resulting in apnoea and a reduction in heart rate. Similarly, airflow within the nasopharynx can elicit the TCR and/or laryngeal chemoreflex (LCR), resulting in glottal closure and ineffective ventilation, whereas providing pressure via inflations could stimulate multiple receptors that affect breathing. Stimulating the fast adapting pulmonary receptors may activate Head's paradoxical reflex to stimulate spontaneous breathing. In contrast, stimulating the slow adapting pulmonary receptors or laryngeal receptors could induce the Hering-Breuer inflation reflex or LCR, respectively, and thereby inhibit spontaneous breathing. As clinicians are most often unaware that starting primary care might affect the breathing they intend to support, this narrative review summarises the currently available evidence on (vagally mediated) reflexes that might promote or inhibit spontaneous breathing at birth.
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Affiliation(s)
- Kristel Kuypers
- Neonatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tessa Martherus
- Neonatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tereza Lamberska
- Neonatology, General University Hospital in Prague, Prague, Czech Republic
| | - Janneke Dekker
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Arjan B Te Pas
- Neonatology, Leiden University Medical Center, Leiden, The Netherlands
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Caspers C, Cleveland S, Schipke JD. Diving reflex: can the time course of heart rate reduction be quantified? Scand J Med Sci Sports 2010; 21:18-31. [PMID: 21083770 DOI: 10.1111/j.1600-0838.2010.01246.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this meta-analysis of diving bradycardia in humans, we sought to quantify any heart rate (HR) reduction using a relatively simple mathematical function. Using the terms "diving reflex,""diving bradycardia,""diving response,""diving plus heart rate," databases were searched. Data from the studies were fitted using HR=c+aexp(-(t-t(0))/τ), where c is the final HR, a is the HR decrease, τ is the time constant of HR decay, and t(0) is the time delay. Of 890 studies, 220 were given closer scrutiny. Only eight of these provided data obtained under comparable conditions. Apneic facial immersion decreased HR with τ=10.4 s and in air alone it was less pronounced and slower (τ=16.2 s). The exponential function fitted the time course of HR decrease closely (r(2)>0.93). The fit was less adequate for apneic-exercising volunteers. During apnea both with and without face immersion, HR decreases along a monoexponential function with a characteristic time constant. HR decrease during exercise with and without face immersion could not readily be described with a simple function: the parasympathetic reaction was partially offset by some sympathetic activity. Thus, we succeeded in quantifying the early time course of diving bradycardia. It is concluded that the diving reflex is useful to diagnose the integrity of efferent cardiovascular autonomic pathways.
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Affiliation(s)
- C Caspers
- Research Group Experimental Surgery, University Hospital Düsseldorf, Düsseldorf, Germany
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Pretorius T, Gagnon DD, Giesbrecht GG. Core cooling and thermal responses during whole-head, facial, and dorsal immersion in 17 °C water. Appl Physiol Nutr Metab 2010; 35:627-34. [DOI: 10.1139/h10-057] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study isolated the effects of dorsal, facial, and whole-head immersion in 17 °C water on peripheral vasoconstriction and the rate of body core cooling. Seven male subjects were studied in thermoneutral air (∼28 °C). On 3 separate days, they lay prone or supine on a bed with their heads inserted through the side of an adjustable immersion tank. Following 10 min of baseline measurements, the water level was raised such that the water immersed the dorsum, face, or whole head, with the immersion period lasting 60 min. During the first 30 min, the core (esophageal) cooling rate increased from dorsum (0.29 ± 0.2 °C·h–1) to face (0.47 ± 0.1 °C·h–1) to whole head (0.69 ± 0.2 °C·h–1) (p < 0.001); cooling rates were similar during the final 30 min (mean, 0.16 ± 0.1 °C·h–1). During the first 30 min, fingertip blood flow (laser Doppler flux as percent of baseline) decreased faster in whole-head immersion (114 ± 52%·h–1) than in either facial (51 ± 47%·h–1) or dorsal (41 ± 55%·h–1) immersion (p < 0.03); rates of flow decrease were similar during minutes 30 to 60 (mean, 22.5 ± 19%·h–1). Total head heat loss over 60 min was significantly different between whole-head (120.5 ± 13 kJ), facial (86.8 ± 17 kJ), and dorsal (46.0 ± 11 kJ) immersion (p < 0.001). The rate of core cooling, relative to head heat loss, was similar in all conditions (mean, 0.0037 ± 0.001 °C·kJ–1). Although the whole head elicited a higher rate of vasoconstriction, the face did not elicit more vasoconstriction than the dorsum. Rather, the progressive increase in core cooling from dorsal to facial to whole-head immersion simply correlates with increased heat loss.
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Affiliation(s)
- Thea Pretorius
- Laboratory for Exercise and Environmental Medicine, Faculty of Kinesiology and Recreation Management, University of Manitoba, 211 Max Bell Centre, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Dominique D. Gagnon
- Laboratory for Exercise and Environmental Medicine, Faculty of Kinesiology and Recreation Management, University of Manitoba, 211 Max Bell Centre, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Gordon G. Giesbrecht
- Laboratory for Exercise and Environmental Medicine, Faculty of Kinesiology and Recreation Management, University of Manitoba, 211 Max Bell Centre, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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Cardiovascular time courses during prolonged immersed static apnoea. Eur J Appl Physiol 2010; 110:277-83. [DOI: 10.1007/s00421-010-1489-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2010] [Indexed: 11/27/2022]
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Andersson JPA, Linér MH, Jönsson H. Increased serum levels of the brain damage marker S100B after apnea in trained breath-hold divers: a study including respiratory and cardiovascular observations. J Appl Physiol (1985) 2009; 107:809-15. [DOI: 10.1152/japplphysiol.91434.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The concentration of the protein S100B in serum is used as a brain damage marker in various conditions. We wanted to investigate whether a voluntary, prolonged apnea in trained breath-hold divers resulted in an increase of S100B in serum. Nine trained breath-hold divers performed a protocol mimicking the procedures they use during breath-hold training and competition, including extensive preapneic hyperventilation and glossopharyngeal insufflation, in order to perform a maximum-duration apnea, i.e., “static apnea” (average: 335 s, range: 281–403 s). Arterial blood samples were collected and cardiovascular variables recorded. Arterial partial pressures of O2 and CO2 (PaO2 and PaCO2) were 128 Torr and 20 Torr, respectively, at the start of apnea. The degree of asphyxia at the end of apnea was considerable, with PaO2 and PaCO2 reaching 28 Torr and 45 Torr, respectively. The concentration of S100B in serum transiently increased from 0.066 μg/l at the start of apnea to 0.083 μg/l after the apnea ( P < 0.05). The increase in S100B is attributed to the asphyxia or to other physiological responses to apnea, for example, increased blood pressure, and probably indicates a temporary opening of the blood-brain barrier. It is not possible to conclude that the observed increase in S100B levels in serum after a maximal-duration apnea reflects a serious injury to the brain, although the results raise concerns considering negative long-term effects. At the least, the results indicate that prolonged, voluntary apnea affects the integrity of the central nervous system and do not preclude cumulative effects.
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Heart rate and blood pressure time courses during prolonged dry apnoea in breath-hold divers. Eur J Appl Physiol 2008; 104:1-7. [DOI: 10.1007/s00421-008-0771-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2008] [Indexed: 10/22/2022]
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Abstract
The cold face test (CFT) evokes reflex bradycardia and pressor responses. Bradycardia has been used to assess vagal function. This study evaluated two aspects of physiology and clinical applicability of the pressor response. During constant monitoring of blood pressure (Finapres) and heart rate (EKG), CFT was induced by the application of three cold packs (0.5 degrees C) to the face for 1 min. Group 1: Latencies of systolic blood pressure (SBP) and heart rate (HR) response to the CFT were recorded in 10 normal subjects. Group 2: CFT was performed in eight normal subjects after cholinergic blockade with atropine (0.03 mg/kg body weight intravenously). Group 3: Four patients with baroreflex failure and five patients with pure autonomic failure were subjected to CFT. In Group 1, mean latency of CFT-induced SBP rise (mean +/- SD) (13.8 +/- 16.6 s) was longer than that of bradycardia (5.6 +/- 4.6 s). In Group 2, bradycardia was abolished in all subjects and SBP was unaffected after atropine administration. In Group 3, patients with baroreflex failure demonstrated normal HR and SBP responses to CFT. In the pure autonomic failure patients, bradycardia was absent and SBP response was either absent or subnormal. The adrenergic phase of the CFT is independent of the cholinergic phase (bradycardia) and baroreceptors. Rise in SBP is useful in evaluating the integrity of the efferent sympathetic pathway with baroreflex failure. Absence of SBP rise in response to the CFT may be of diagnostic value in detecting the sympathetic component of pure autonomic failure.
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Affiliation(s)
- Ramesh K Khurana
- The Union Memorial Hospital, 201 East University Parkway, Room 411, 33rd Street Building, Baltimore, MD 21218, USA.
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Wein J, Andersson JP, Erdéus J. Cardiac and ventilatory responses to apneic exercise. Eur J Appl Physiol 2007; 100:637-44. [PMID: 17661074 DOI: 10.1007/s00421-007-0411-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2007] [Indexed: 11/24/2022]
Abstract
This study was to elucidate the physiological effects of dynamic apneas, as performed as a discipline in breath-hold diving for recreational or competitive purposes. Therefore, cardiovascular and respiratory effects of apneas with simultaneously initiated exercise were investigated in ten trained breath-hold divers. They performed maximum duration apneas with face immersion (26 degrees C) under rest and exercise (40 W, 80 W and 120 W) on a cycle ergometer in the laboratory. Apneic time, heart rate (HR), mean arterial pressure (MAP), arterial oxygen saturation and O2 (.VO2) and CO2 exchange were measured. All end-apnea heart rates were lower than corresponding control values. Higher workloads increased the initial rise in HR and delayed the onset of bradycardia. After an initial drop, MAP rose to 150% of control towards the end of apnea. Apneic .VO2 was reduced by 25% during exercise and by 40% during resting apneas compared to eupneic control values. It was concluded that magnitude and time course of diving bradycardia depend on work intensity. Higher workloads delay the onset and attenuate HR reduction, presumably due to increased sympathetic activity. It was also found that apnea with simultaneously initiated exercise has an O2 conserving effect compared to eupneic exercise. Although aimed to be a realistic approach to breath-hold diving, the study has certain methodological limitations in terms of body-immersion (hydrostatic pressure effects) and body-cooling effects due to conduction of the experiments in a laboratory set-up.
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Affiliation(s)
- Jens Wein
- Department of Ecology, Biocentre Grindel, Hamburg University, Martin-Luther-King Platz 3, Hamburg, Germany.
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Abstract
The purpose of this review is to outline the physiological responses associated with the diving response, its functional significance, and its cardiorespiratory control. This review is separated into four major sections. Section one outlines the diving response and its physiology. Section two provides support for the hypothesis that the primary role of the diving response is the conservation of oxygen. The third section describes how the diving response is controlled and provides a model that illustrates the cardiorespiratory interaction. Finally, the fourth section illustrates potential adaptations that result after regular exposure to an asphyxic environment. The cardiovascular and endocrine responses associated with the diving response and apnea are bradycardia, vasoconstriction, and an increase in secretion of suprarenal catecholamines. These responses require the integration of both the cardiovascular system and the respiratory system. The primary role of the diving response is likely to conserve oxygen for sensitive brain and heart tissue and to lengthen the time before the onset of serious hypoxic damage. We suggest that future research should be focused towards understanding the role of altered ventilatory responses in human breath-hold athletes as well as in patients suffering from sleep-disordered breathing.
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Affiliation(s)
- G E Foster
- Health and Integrative Physiology Laboratory, School of Human Kinetics, University of British Columbia, Vancouver, BC, Canada
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