ORCID Profile
0000-0003-0524-2642
Current Organisation
University of Tasmania
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Publisher: BMJ
Date: 15-09-2016
DOI: 10.1136/ARCHDISCHILD-2016-310650
Abstract: To assess the performance of a novel algorithm for automated oxygen control using a simulation of oxygenation founded on in vivo data from preterm infants. A proportional-integral-derivative (PID) control algorithm was enhanced by (i) compensation for the non-linear SpO Separate addition of each enhancing feature to the PID algorithm showed a benefit, but not with uniformly positive effects. The fully enhanced algorithm was optimal for the combination of targeting the desired SpO An enhanced PID algorithm was very effective for automated oxygen control in a simulation of oxygenation, and deserves clinical evaluation.
Publisher: IEEE
Date: 08-2010
Publisher: IEEE
Date: 12-2012
Publisher: Springer Science and Business Media LLC
Date: 20-02-2016
DOI: 10.1007/S10877-016-9847-3
Abstract: Automated control of inspired oxygen for newborn infants is an emerging technology, currently limited by reliance on a single input signal (oxygen saturation, SpO
Publisher: IEEE
Date: 10-2013
Publisher: IEEE
Date: 11-2014
Publisher: IEEE
Date: 04-2013
Publisher: Wiley
Date: 16-07-2019
DOI: 10.1002/PPUL.24451
Abstract: The factors influencing the severity of apnea-related hypoxemia and bradycardia are incompletely characterized, especially in infants receiving noninvasive respiratory support. To identify the frequency and predictors of physiological instability (hypoxemia-oxygen saturation (SpO Respiratory pause duration, derived from capsule pneumography, was measured in 30 preterm infants of gestation 30 (24-32) weeks [median (interquartile range)] receiving noninvasive respiratory support and supplemental oxygen. For identified pauses of 5 to 29 seconds duration, we measured the magnitude and duration of SpO In total, 17 105 isolated and 9180 clustered pauses were identified. Hypoxemia and bradycardia were more likely after longer duration and temporally-clustered pauses. However, the majority of such episodes occurred after 5 to 9 second pauses given their numerical preponderance, and short-lived pauses made a substantial contribution to physiological instability overall. Birth gestation, hemoglobin concentration, form of respiratory support, caffeine treatment, respiratory pause duration and temporal clustering were identified as predictors of instability. Brief respiratory pauses, especially when clustered, contribute substantially to hypoxemia and bradycardia in preterm infants.
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.JPEDS.2013.11.072
Abstract: The precision of oxygen saturation (SpO2) targeting in preterm infants on continuous positive airway pressure (CPAP) is incompletely characterized. We therefore evaluated SpO2 targeting in infants solely receiving CPAP, aiming to describe their SpO2 profile, to document the frequency of prolonged hyperoxia and hypoxia episodes and of fraction of inspired oxygen (FiO2) adjustments, and to explore the relationships with neonatal intensive care unit operational factors. Preterm infants <37 weeks' gestation in 2 neonatal intensive care units were studied if they were receiving CPAP and in supplemental oxygen at the beginning of each 24-hour recording. SpO2, heart rate, and FiO2 were recorded (s ling interval 1-2 seconds). We measured the proportion of time spent in predefined SpO2 ranges, the frequency of prolonged episodes (≥30 seconds) of SpO2 deviation, and the effect of operational factors including nurse-patient ratio. A total of 4034 usable hours of data were recorded from 45 infants of gestation 30 (27-32) weeks (median [IQR]). When requiring supplemental oxygen, infants were in the target SpO2 range (88%-92%) for only 31% (19%-39%) of total recording time, with 48 (6.9-90) episodes per 24 hours of severe hyperoxia (SpO2 ≥98%), and 9.0 (1.6-21) episodes per 24 hours of hypoxia (SpO2 <80%). An increased frequency of prolonged hyperoxia in supplemental oxygen was noted when nurses were each caring for more patients. Adjustments to FiO2 were made 25 (16-41) times per day. SpO2 targeting is challenging in preterm infants receiving CPAP support, with a high proportion of time spent outside the target range and frequent prolonged hypoxic and hyperoxic episodes.
Publisher: IEEE
Date: 08-2011
Publisher: EJournal Publishing
Date: 2013
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2007
Publisher: S. Karger AG
Date: 11-11-2015
DOI: 10.1159/000440642
Abstract: b i Background: /i /b Oxygen saturation (SpO sub /sub ) targeting in the preterm infant may be improved with a better understanding of the SpO sub /sub responses to changes in inspired oxygen (FiO sub /sub ). b i Objective: /i /b We investigated the first-order FiO sub /sub -SpO sub /sub relationship, aiming to quantify the parameters governing that relationship, the influences on these parameters and their variability. b i Methods: /i /b In recordings of FiO sub /sub and SpO sub /sub from preterm infants on continuous positive airway pressure and supplemental oxygen, we identified unique FiO sub /sub adjustments and mapped the subsequent SpO sub /sub responses. For responses identified as first-order, the delay, time constant and gain parameters were determined. Clinical and physiological predictors of these parameters were sought in regression analysis, and intra- and inter-subject variability was evaluated. b i Results: /i /b In 3,788 h of available data from 47 infants at 31 (28-33) post-menstrual weeks [median (interquartile range)], we identified 993 unique FiO sub /sub adjustments followed by a first-order SpO sub /sub response. All response parameters differed between FiO sub /sub increments and decrements, with increments having a shorter delay, longer time constant and higher gain [2.9 (1.7-4.8) vs. 1.3 (0.58-2.6), p 0.05]. Gain was also higher in less mature infants and in the setting of recent SpO sub /sub instability, and was diminished with increasing severity of lung dysfunction. Intra-subject variability in all parameters was prominent. b i Conclusions: /i /b First-order SpO sub /sub responses show variable gain, influenced by the direction of FiO sub /sub adjustment and the severity of lung disease, as well as substantial intra-subject parameter variability. These findings should be taken into account in adjustment of FiO sub /sub for SpO sub /sub targeting in preterm infants.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2016
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 28-07-2017
DOI: 10.1007/S10916-017-0782-8
Abstract: Imaging systems have applications in patient respiratory monitoring but with limited application in neonatal intensive care units (NICU). In this paper we propose an algorithm to automatically detect the torso in an image of a preterm infant during non-invasive respiratory monitoring. The algorithm uses normalised cut to segment each image into clusters, followed by two fuzzy inference systems to detect the nappy and torso. Our dataset comprised overhead images of 16 preterm infants in a NICU, with uncontrolled illumination, and encompassing variations in poses, presence of medical equipment and clutter in the background. The algorithm successfully identified the torso region for 15 of the 16 images, with a high agreement between the detected torso and the torso identified by clinical experts.
Publisher: BMJ
Date: 08-06-2015
DOI: 10.1136/ARCHDISCHILD-2014-308108
Abstract: Oxygen saturation (SpO2) signal dropout leaves caregivers without a reliable measure to guide oxygen therapy. We studied SpO2 dropout in preterm infants on continuous positive airway pressure, noting the SpO2 values at signal loss and recovery and thus the resultant change in SpO2, and the factors influencing this parameter. In 32 infants of median gestation 26 weeks, a total of 3932 SpO2 dropout episodes were identified (1.1 episodes/h). In the episodes overall, SpO2 decreased by 1.1%, with the SpO2 change influenced by starting SpO2 (negative correlation), but not dropout duration. For episodes starting in hypoxia (SpO2 <85%), SpO2 recovered at a median of 3.2% higher than at SpO2 dropout, with a downward trajectory in a quarter of cases. We conclude that after signal dropout SpO2 generally recovers in a relative normoxic range. Blind FiO2 adjustments are thus unlikely to be of benefit during most SpO2 dropout episodes.
Publisher: IOP Publishing
Date: 29-05-2014
DOI: 10.1088/0967-3334/35/7/1425
Abstract: In this paper an investigation of the gain, delay, and time-constant parameters of the transfer function describing the relation between fraction of inspired oxygen (FiO2) and oxygen saturation in the blood (SpO2) in preterm infants is presented. The parameters were estimated following FiO2 adjustments and goodness of fit was used to assess the validity of the model when using an assumed first-order transfer function. For responses identified to be first-order, the estimated parameters were then clustered to identify areas where they tended to be concentrated. Each group described an operating region of the transfer function thus, predicting the right operating region could potentially assist a range-based robust inspired oxygen controller to provide more optimal control by adapting itself to different clusters. Accordingly, the s les were assigned labels based on their cluster associations and 14 features available at the time of each adjustment were used as inputs to an artificial neural network to classify the clustered s les. The validity study suggested that 37% of the adjustments were followed by first-order responses. Prediction studies on the first-order responses indicated that the clusters could be predicted with an average accuracy of 64% when the parameters were ided into two groups.
Publisher: IEEE
Date: 11-2015
Publisher: Elsevier BV
Date: 07-2016
Publisher: IEEE
Date: 04-2013
Publisher: BMJ
Date: 29-08-2016
DOI: 10.1136/ARCHDISCHILD-2016-310647
Abstract: To evaluate the performance of a novel rapidly responsive proportional-integral-derivative (PID) algorithm for automated oxygen control in preterm infants with respiratory insufficiency. Interventional study of a 4-hour period of automated oxygen control compared with combined data from two flanking periods of manual control (4 hours each). Neonatal intensive care unit. Preterm infants (n=20) on non-invasive respiratory support and supplemental oxygen, with oxygen saturation (SpO Automated oxygen control using a standalone device, receiving SpO Proportion of time in the SpO Automated oxygen control resulted in more time in the target range or above in air (manual 56 (48-63)% vs automated 81 (76-90)%, p 0.05). The novel PID algorithm was very effective for automated oxygen control in preterm infants, and deserves further investigation.
Publisher: Wiley
Date: 02-09-2016
DOI: 10.1002/CTA.2127
Publisher: Elsevier BV
Date: 04-2008
No related grants have been discovered for Timothy Gale.