C Parsley

Women`s and Children`s Hospital, Tarndarnya, South Australia, Australia

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Publications (10)7.47 Total impact

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    ABSTRACT: Pulse oximetry is used extensively in hospital and home settings to measure arterial oxygen saturation (SpO2). Interpretation of the trend and range of SpO2 values observed in infants is currently limited by a lack of reference ranges using current devices, and may be augmented by development of cumulative frequency (CF) reference-curves. This study aims to provide reference oxygen saturation values from a prospective longitudinal cohort of healthy infants.
    Archives of disease in childhood. 07/2014;
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    ABSTRACT: Non-invasive monitoring of breathing is a holy grail in paediatric respiratory, neonatal and sleep medicine. Respiratory rate is a key marker for the surveillance of sick infants and children (1-3), while repeated infant apnoeic episodes are associated with an increased risk of apparent life-threatening events (4). In clinical pulse oximetry, the photoplethysmographic (pleth) signal is assessed mainly to infer the validity of measured arterial oxygen saturation. This article is protected by copyright. All rights reserved.
    Acta Paediatrica 01/2014; · 1.97 Impact Factor
  • The 24th Annual Scientific meeting of the Australasian Sleep Association and the Australasian Sleep Technologists Association, Darwin, Australia; 10/2012
  • Australian Biomedical Engineering Conference, Brisbane, Australia; 09/2012
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    ABSTRACT: This study characterises and describes the maturational evolution of the healthy infant sleep electroencephalogram (EEG) longitudinally from 2 weeks to 24 months of age, by means of power spectral analysis. A prospective cohort of 34 healthy infants underwent overnight polysomnography (PSG) at 2 weeks, and at 3, 6, 12 and 24 months of age. Sleep epochs were scored as Active Sleep (AS) and Quiet Sleep (QS) at 2 weeks of age and as Rapid Eye Movement (REM) and Non-REM (NREM) stages from 3 months onwards. Representative epochs were used to generate the EEG power spectra, from the central C3 derivation. These were analysed visually and quantitatively in AS/REM and QS/NREM sleep in the following bandwidths: delta (0.5-4 Hz); theta (4-8 Hz); alpha (8-11 Hz); sigma (11-15 Hz) and 0.5-25 Hz. Sleep EEG (central derivation) power spectra changed significantly in the different bandwidths as the infants matured. The emergence of a peak in the sigma bandwidth in NREM N2 sleep corresponded with the development of sleep spindles. Maturational changes were also seen in NREM N3 and in theta and alpha bandwidths in both AS/REM and QS/NREM. Sleep EEG power spectra characteristics in healthy infants evolve in keeping with maturation and neurodevelopmental milestones. This study provides an atlas of healthy infant sleep EEG in the early years of life, providing a basis for association with other neurodevelopmental measures and a normative dataset on which disease may be discriminated.
    Clinical neurophysiology: official journal of the International Federation of Clinical Neurophysiology 02/2011; 122(2):236-43. · 3.12 Impact Factor
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    ABSTRACT: In adults, ventilation is preferentially distributed towards the dependent lung. A reversal of the adult pattern has been observed in infants using radionuclide ventilation scanning. But these results have been obtained in infants and children with lung disease. In this study we investigate whether healthy infants have a similar reverse pattern of ventilation distribution. Measurement of regional ventilation distribution in healthy newborn infants during non-REM sleep in comparison to adults. Twenty-four healthy newborns and 13 adults were investigated with electrical impedance tomography (EIT) in supine and prone position. Regional ventilation distribution was assessed with profiles of relative impedance change. The phase lag between dependent and non-dependent ventilation was calculated as a measure of asynchronous ventilation. In newborns and adults the geometric center of ventilation was centrally located in the lung at 52.2 +/- 6.2% from anterior to posterior and at 50.5 +/- 14.7%, respectively. Using impedance profiles, ventilation was equally distributed to the dependent and non-dependent lung regions in newborns. Ventilation distribution in adults was similar. Phase lag characteristics of the impedance signal showed that infants had slower emptying of the dependent lung than adults. The speculated reverse pattern of regional ventilation distribution in healthy infants compared to adults could not be demonstrated. Gravity had little effect on ventilation distribution in both infants and adults measured in supine and prone position.
    Pediatric Pulmonology 09/2009; 44(9):851-8. · 2.38 Impact Factor
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    ABSTRACT: The prevalence of sudden infant death syndrome (SIDS) has been well studied and central sleep apnea is deemed as one of the possible causes. Current gold standard for its diagnosis is nocturnal polysomnography (PSG). However, this procedure is complex and generally needs to be performed in a sleep laboratory. Pulse transit time (PTT) shows its potential to indicate abrupt blood pressure (BP) changes during the occurrences of upper airway obstruction. The main objective of this study was to assess the capability of PTT to differentiate central respiratory events from tidal breathing in infants. This study involved 5 infants (4 male) with mean age of 7.8 months. 50 valid central respiratory events were randomly selected. These events were free from motion artifacts and pre-scored in the corresponding PSG studies by two blinded observers. PTT measurements from these events were then evaluated against the PSG scorings. Using a two-tailed F-test for variance, it was observed that central events differed from tidal breathing in a significant manner (p<0.05). Furthermore, PTT has showed its sensitivity to monitor marginal BP fluctuations during tidal breathing. Hence, the results herein suggest that PTT can be a valuable non-invasive technique to monitor central apneic events in sleeping infants.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2005; 3:2579-82.
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    ABSTRACT: Pulse transit time (PTT) is a non-invasive measure, defined as time taken for the pulse pressure waves to travel from the R-wave of electrocardiogram to a selected peripheral site. Baseline PTT value is known to be influenced by physiologic variables like heart rate (HR), blood pressure (BP) and arterial compliance (AC). However, few quantitative data are available describing the factors which can influence PTT measurements in a child during breathing. The aim of this study was to investigate the effects of changes in breathing efforts on PTT baseline and fluctuations. Two different inspiratory resistive loading (IRL) devices were used to simulate loaded breathing in order to induce these effects. It is known that HR can influence the normative PTT value however the effect of HR variability (HRV) is not well-studied. Two groups of 3 healthy children (≤12years) were recruited; one group with insignificant (p>0.05) HR changes during all test activities. Results showed that HRV is not the sole contributor to PTT variations and suggest that changes in other physiologic parameters are also equally important. Hence, monitoring PTT measurement can be indicative of these associated changes during tidal or increased breathing efforts in healthy children.
    Conference proceedings: ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference 01/2005; 7:7521-4.