Mark Tracy

Mark Tracy
The University of Sydney · Discipline of Paediatrics and Child Health

PhD MSc (Epi) FRACP MBBS

About

124
Publications
16,273
Reads
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2,243
Citations
Introduction
Mark Tracy currently works at the Discipline of Paediatrics and Child Health, University of Sydney. Mark does research in Newborn Intensive Care Medicine in the following areas 1. resuscitation methods, devices and performance 2. perinatal epidemiology 3. NIRS cerebral blood flow in newborns 4. Mathematical modelling of NICU physiology using high resolution data
Additional affiliations
February 1998 - present
The University of Sydney
Position
  • Clinical Senior Lecturer

Publications

Publications (124)
Preprint
PurposeIn neonatal resuscitation, using a T-piece resuscitator (TPR) is used widely, however the evidence is limited for the use in infants born at term gestation. The aim of this study was to compare the positive end expiratory pressure (PEEP) and respiratory system resistance ( R rs) using TPR and self-inflating bag (SIB) in a cadaveric piglet mo...
Preprint
Purpose: Newborn mask ventilation technique requires skills, and effective resuscitation is essential for pulmonary gas exchange. The most effective compression to ventilation (C:V) ratio in newborn resuscitation is still contentious and there is no evidence of human data supporting the current 3:1 ratio. We aimed to study mask leak and respiratory...
Preprint
PurposeNewborn infant is particularly vulnerable around the time of birth and events during this period can have impact on survival and neurodevelopmental outcomes. Having trained personnel with familiar equipment is of paramount importance. We aimed to explore the neonatal training experience of birth attendants in New South Wales (NSW) and Austra...
Article
This review addresses regional oxygenation and perfusion changes for preterm infants and changes with body position, with or without head rotation. Future directions for improving neurodevelopmental and clinical outcomes are suggested. The MEDLINE, Embase and Scopus databases were searched up to July 2021. Fifteen out of 470 studies met the inclusi...
Article
Contemporary packed red blood cell transfusion practices in anaemic preterm infants are primarily based on measurement of haemoglobin or haematocrit. In neonatal intensive care units, most preterm infants receive at least one packed red cell transfusion as standard treatment for anaemia of prematurity. Clinicians are faced with a common question “a...
Article
Full-text available
Background: The administration of live microbiota (probiotic) via enteral route to preterm infants facilitates intestinal colonization with beneficial bacteria, resulting in competitive inhibition of the growth of pathogenic bacteria preventing gut microbiome dysbiosis. This dysbiosis is linked to the pathogenesis of necrotizing enterocolitis (NEC)...
Preprint
Abdominal auscultation is a convenient, safe and inexpensive method to assess bowel conditions, which is essential in neonatal care. It helps early detection of neonatal bowel dysfunctions and allows timely intervention. This paper presents a neonatal bowel sound detection method to assist the auscultation. Specifically, a Convolutional Neural Netw...
Article
Full-text available
Objectives We compared intrapartum interventions and outcomes for mothers, neonates and children up to 16 years, for induction of labour (IOL) versus spontaneous labour onset in uncomplicated term pregnancies with live births. Design We used population linked data from New South Wales, Australia (2001–2016) for healthy women giving birth at 37+0 t...
Article
Full-text available
Background: Resuscitation of infants using T-piece resuscitators (TPR) allow positive pressure ventilation with positive end-expiratory pressure (PEEP). The adjustable PEEP valve adds resistance to expiration and could contribute to inadvertent PEEP. The study indirectly investigated risk of inadvertent peep by determining expiratory time constants...
Article
Objectives: To evaluate cerebral oxygenation (cTOI) and cerebral perfusion in preterm infants in supine versus prone positions. Study design: Sixty preterm infants, born before 32 weeks gestation, were enrolled; 30 had bronchopulmonary dysplasia (BPD, defined as the need for respiratory support and/or supplemental oxygen at 36 weeks post menstru...
Article
Infant resuscitation devices used at birth must be capable of delivering adequate and consistent ventilation in a controlled and predictable manner to a wide patient weight range, and combinations of transitional lung states. Manual inflation resuscitation devices delivering positive pressure lung inflation at birth can be classified broadly into t...
Article
This is an Australia New Zealand Neonatal Network (ANZNN) wide survey to identify current practice and guide future practice improvement for the use of laryngeal mask airway (LMA) during neonatal resuscitation. An online questionnaire containing 13 questions was sent out to all tertiary neonatal centres (n = 29 units) and neonatal transport units (...
Article
Background: Very low birthweight or preterm infants are at increased risk of adverse outcomes including sepsis, necrotising enterocolitis, and death. We assessed whether supplementing the enteral diet of very low-birthweight infants with lactoferrin, an antimicrobial protein, reduces all-cause mortality or major morbidity. Methods: We did a multic...
Article
Background T-piece resuscitators (TPRs) are used for primary newborn resuscitation in birthing and emergency rooms worldwide. A recent study has shown spikes in peak inflation pressure (PIP) over set values with two brands of TPRs inbuilt into infant warmer/resuscitation platforms. We aimed to compare delivered ventilation between two TPR drivers w...
Article
Background and Objectives In anaemic preterm infants who receive packed red blood cell (PRBC) transfusions, changes to mesenteric tissue oxygenation and perfusion have been reported using a restrictive haemoglobin (Hb)‐based threshold. We aimed to investigate changes to hepatic tissue oxygenation and abdominal blood flow after PRBC transfusion and...
Article
Background Very low birthweight or preterm infants are at increased risk of adverse outcomes including sepsis, necrotising enterocolitis, and death. We assessed whether supplementing the enteral diet of very low-birthweight infants with lactoferrin, an antimicrobial protein, reduces all-cause mortality or major morbidity. Methods We did a multicen...
Article
Aim: The use of umbilical arterial catheters (UACs) is a standard of care in monitoring critically unwell infants. Serious vascular complications are rare but when they do occur, they can be associated with significant morbidity, risking limb loss or even death. Near infra-red spectroscopy has the potential to monitor limb perfusion. Our study inv...
Article
Full-text available
Background: The measurement and interpretation of patient experience is a distinct dimension of health care quality. The Midwives @ New Group practice Options (M@NGO) randomized control trial of caseload midwifery compared with standard care among women regardless of risk reported both clinical and cost benefits. This study reports participants' p...
Article
Background: Red blood cell (RBC) transfusion is a standard treatment for anemia of prematurity. Cerebral tissue oxygenation and blood flow velocities improve when a restrictive transfusion threshold is followed, but little is known about the effect of practicing a liberal transfusion threshold on cerebral tissue oxygenation, cerebral blood flow ve...
Article
Aim To evaluate cerebral autoregulation changes in preterm infants receiving a loading dose of caffeine base. Methods In a cohort of 30 preterm infants, we extracted measures of cerebral autoregulation using time and frequency domain techniques to determine the correlation between mean arterial pressure (MAP) and tissue oxygenation index (TOI) sig...
Article
Full-text available
Aim A controlled bench test was undertaken to determine the performance variability among a range of neonatal self-inflating bags (SIB) compliant with current International Standards Organisation (ISO). Introduction Use of SIB to provide positive pressure ventilation during newborn resuscitation is a common emergency procedure. The United Nations...
Article
Full-text available
Introduction This review acquaints neonatal clinicians using point‐of‐care ultrasound with a range of pathological bowel ultrasound findings, with the aim to promote utility of this skill as a diagnostic assessment tool in diseased neonatal intestinal states. Overview A range of normal and pathological bowel ultrasound findings are illustrated wit...
Article
Background: The T-piece resuscitator (TPR) has seen increased use as a primary resuscitation device with newborns. Traditional TPR design uses a high resistance expiratory valve to produce PEEP/CPAP. A new TPR device which uses a dual flow ratio valve (fluidic flip) to produce PEEP/CPAP at resuscitation is now available (rPAP). We aimed to compare...
Article
Aim To evaluate the acute effect of intravenous caffeine on heart rate and blood pressure variability in preterm infants. Methods We extracted and compared linear and non‐linear features of heart rate and blood pressure variability at two timepoints: prior to and in the two hours following a loading dose of 10 mg/kg caffeine base. Results We stud...
Article
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Poor postnatal mental health is a major public health issue, and risk factors include experiencing adverse life events during pregnancy. We assessed whether midwifery group practice, compared to standard hospital care, would protect women from the negative impact of a sudden-onset flood on postnatal depression and anxiety. Women either received mid...
Article
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Background Spontaneous vaginal birth rates are decreasing worldwide, while cesarean delivery, instrumental births, and medical birth interventions are increasing. Emerging evidence suggests that birth interventions may have an effect on children's health. Therefore, the aim of our study was to examine the association between operative and medical b...
Article
Management and monitoring of infants within the neonatal intensive care unit (NICU) represents a unique challenge. It involves an array of life-threatening diseases, procedures with potentially lifelong impacts, co-morbidities associated with preterm birth and risk of infection from prolonged exposure to the hospital environment. With the integrati...
Article
Background International neonatal resuscitation guidelines recommend the use of laryngeal mask airway (LMA) with newborn infants (≥34 weeks’ gestation or >2 kg weight) when bag-mask ventilation (BMV) or tracheal intubation is unsuccessful. Previous publications do not allow broad LMA device comparison. Objective To compare delivered ventilation of...
Article
Full-text available
Objective To compare maternal and neonatal birth outcomes and morbidities associated with the intention to give birth in a freestanding primary level midwife-led maternity unit (PMU) or tertiary level obstetric-led maternity hospital (TMH) in Canterbury, Aotearoa/New Zealand. Design Prospective cohort study. Participants 407 women who intended to...
Article
Aim: The aim of this study was to compare mask leak with three different peak inspiratory pressure (PIP) settings during T-piece resuscitator (TPR; Neopuff) mask ventilation on a neonatal manikin model. Methods: Participants were neonatal unit staff members. They were instructed to provide mask ventilation with a TPR with three PIP settings (20,...
Article
Full-text available
Despite the decline in mortality rates of extremely preterm infants, intraventricular haemorrhage (IVH) remains common in survivors. The need for resuscitation and cardiorespiratory management, particularly within the first 24 hours of life, are important factors in the incidence and timing of IVH. Variability analyses of heart rate and blood press...
Article
Objective: to explore whether women allocated to caseload care characterise their midwife differently to those allocated to standard care. Design: multi-site unblinded, randomised, controlled, parallel-group trial. Setting: the study was conducted in two metropolitan teaching hospitals across two Australian cities. Population: women of all o...
Article
Background: the viability of freestanding midwifery units in Australia is restricted, due to concerns over their safety, particularly for women and babies who, require transfer. Aim: to compare the maternal and neonatal birth outcomes of women who planned, to give birth at freestanding midwifery units and subsequently, transferred to a tertiary...
Article
Background: Manual resuscitation devices for infants and newborns must be able to provide adequate ventilation in a safe and consistent manner across a wide range of patient sizes (0.5-10 kg) and differing clinical states. There are little comparative data assessing biomechanical performance of common infant manual resuscitation devices across the...
Article
Introduction: Amniotic fluid lactate research is based on the hypothesis that a relationship exists between fatigued uterine muscles and raised concentrations of the metabolite lactate, which is excreted into the amniotic fluid during labor. To assess potentially confounding effects of lactate producing organisms on amniotic fluid lactate measurem...
Article
Background The T-piece resuscitator (TPR) is in common use worldwide to deliver positive pressure ventilation during resuscitation of infants <10 kg. Ease of use, ability to provide positive end-expiratory pressure (PEEP), availability of devices inbuilt into resuscitaires and cheaper disposable options have increased its popularity as a first-line...
Article
Neonatal endotracheal intubation is commonly accompanied by significant disturbances in physiological parameters. The procedure is often poorly tolerated, and multiple attempts are commonly required before the airway is secured. Adverse physiological effects include hypoxemia, bradycardia, hypertension, elevation in intracranial pressure and possib...
Article
Full-text available
Background: Non-invasive continuous positive airways pressure is commonly a primary respiratory therapy delivered via multi-purpose ventilators in premature newborns. Expiratory limb occlusion due to water accumulation or 'rainout' from gas humidification is a frequent issue. A case of expiratory limb occlusion due to rainout causing unexpected an...
Article
Background The self-inflating bag (SIB) is the most common device used to resuscitate newborn infants worldwide. Delivering positive end-expiratory pressure (PEEP) may be important in infant resuscitation and limited research using one brand (Laerdal) SIB has led to international guidelines stating SIBs ‘often deliver inconsistent positive end-expi...
Article
Full-text available
Background There is worldwide debate regarding the appropriateness and safety of different birthplaces for well women. The Evaluating Maternity Units (EMU) study’s primary objective was to compare clinical outcomes for well women intending to give birth in either a tertiary level maternity hospital or a freestanding primary level maternity unit. Li...
Article
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to examine the transfers from primary maternity units to a tertiary hospital in New Zealand by describing the frequency, timing, reasons and outcomes of those who had antenatal or pre-admission birthplace plan changes, and transfers in labour or postnatally. mixed methods prospective (concurrent) cohort study, which analysed transfer and clinical o...
Article
Adolescent pregnancy is associated with adverse outcomes including preterm birth, admission to the neonatal intensive care unit, low birth weight infants, and artificial feeding. To determine if caseload midwifery or young women's clinic are associated with improved perinatal outcomes when compared to standard care. A retrospective cohort study. A...
Article
Full-text available
The level of lactate in amniotic fluid may provide useful clinical information when assessing whether a woman in labour is experiencing labour dystocia. If so, a rapid, reliable method to assess the concentration of amniotic fluid lactate at the bedside will be required in order to be clinically relevant. To assess efficacy, we compared the hand he...
Article
Full-text available
Background Women at low risk of pregnancy complications benefi t from continuity of midwifery care, but no trial evidence exists for women with identifi ed risk factors. We aimed to assess the clinical and cost outcomes of caseload midwifery care for women irrespective of risk factors.
Article
Full-text available
Objective To compare maternal and neonatal birth outcomes and morbidities associated with the intention to give birth in two freestanding midwifery units and two tertiary-level maternity units in New South Wales, Australia. Design Prospective cohort study. Participants 494 women who intended to give birth at freestanding midwifery units and 3157 wo...
Article
Full-text available
Objectives To examine the rates of obstetric intervention and associated perinatal mortality and morbidity in the first 28 days among low-risk women giving birth in private and public hospitals in NSW (2000–2008). Design Linked data population-based retrospective cohort study involving five data sets. Setting New South Wales, Australia. Participant...
Chapter
This is the protocol for a review and there is no abstract. The objectives are as follows: To determine the safety and efficacy of different cutaneous antisepsis regimens for prevention of sepsis in newborn infants. Planned subgroup comparisons would include term infants and preterm infants, as well as various types of intravenous access.
Article
Full-text available
In many countries midwives act as the main providers of care for women throughout pregnancy, labour and birth. In our large public teaching hospital in Australia we restructured the way midwifery care is offered and introduced caseload midwifery for one third of women booked at the hospital. We then compared the costs and birth outcomes associated...
Article
Full-text available
To determine changes in respiratory mechanics when chest compressions are added to mask ventilation, as recommended by the International Liaison Committee On Resuscitation (ILCOR) guidelines for newborn infants. Using a Laerdal Advanced Life Support leak-free baby manikin and a 240 mL self-inflating bag, 58 neonatal staff members were randomly pair...
Conference Paper
Full-text available
Methods Abstract Objectives Results Conclusions The primary aim of this study was to compare these devices with in terms of their effect on PEEP and Raw normally compliant (equivalent to term gestation) and poorly compliant lungs (preterm gestation) T-piece device is widely used to deliver PEEP in preterm infants and increasingly being used for ter...
Article
Background Women at low risk of pregnancy complications benefi t from continuity of midwifery care, but no trial evidence exists for women with identifi ed risk factors. We aimed to assess the clinical and cost outcomes of caseload midwifery care for women irrespective of risk factors.
Article
Full-text available
Women at low risk of pregnancy complications benefit from continuity of midwifery care, but no trial evidence exists for women with identified risk factors. We aimed to assess the clinical and cost outcomes of caseload midwifery care for women irrespective of risk factors. In this unblinded, randomised, controlled, parallel-group trial, pregnant wo...
Article
Full-text available
This study investigated whether arterial blood pressure waveform analysis could be useful for estimating left ventricular outflow (LVO) and total peripheral resistance (TPR) in preterm infants. A cohort of 27 infants were studied, with 89 measurements of left ventricular outflow (LVO) using Doppler echocardiography and arterial pressure using cathe...
Article
Full-text available
Very preterm infants are at high risk of death and serious permanent brain damage, as occurs with intraventricular hemorrhage (IVH). Detrended fluctuation analysis (DFA) that quantifies the fractal correlation properties of physiological signals has been proposed as a potential method for clinical risk assessment. This study examined whether DFA of...