Mark Tracy

The University of Sydney · Discipline of Paediatrics and Child Health

Introduction Assessment of bowel health in ill preterm infants is essential to prevent and diagnose early potentially life-threatening intestinal conditions such as necrotizing enterocolitis. Auscultation of bowel sounds helps assess peristalsis and is an essential component of this assessment. Aim We aim to compare conventional bowel sound auscul...

Background: Respiratory function monitors (RFM) have been used extensively in manikin and infant studies yet have not become the standard of training. We report the outcomes of a new portable, lightweight resuscitation monitor (Juno) designed to show mask leak and deflation tidal volume to assist in positive pressure ventilation (PPV) competency tr...

Background: Newborn resuscitation guidelines recommend positive pressure ventilation (PPV) for newborns who do not establish effective spontaneous breathing after birth. T-piece resuscitator systems are commonly used in high-resource settings and can additionally provide positive end-expiratory pressure (PEEP). Short expiratory time, high resistan...

Objective To describe the neonatal training experience of birth attendants in New South Wales (NSW) and Australian Capital Territory (ACT) and explore the variations in respiratory management and equipment use at birth. Methods We contacted 119 nontertiary units in NSW/ACT by a written survey followed by telephone contact. A set questionnaire was...

Emergency research studies are high-stakes studies that are usually performed on the sickest patients, where many patients or guardians have no opportunity to provide full informed consent prior to participation. Many emergency studies self-select healthier patients who can be informed ahead of time about the study process. Unfortunately, results f...

This review describes the sonographic appearances of the neonatal bowel in Necrotising enterocolitis. It compares these findings to those seen in midgut-Volvulus, obstructive intestinal conditions such as milk-curd obstruction, and slow gut motility in preterm infants on continuous positive airway pressure (CPAP)-CPAP belly syndrome. Point-of-care...

Introduction: Low pressure nasal continuous positive airway pressure (nCPAP) has long been the mainstay of non-invasive respiratory support for preterm neonates, at a constant distending pressure of 5-8 cmH2O. When traditional nCPAP pressures are insufficient, other modes including nasal intermittent positive pressure ventilation (NIPPV) are used....

Background Mask leak and airway obstruction are common with mask ventilation in newborn infants, leading to suboptimal ventilation. We aimed to perform a pilot study measuring respiratory mechanics during one-person and two-person mask ventilation in preterm infants at birth. Methods Infants less than 30 weeks’ gestation were eligible for the stud...

Background With the impact of over two centuries of colonisation in Australia, First Nations families experience a disproportionate burden of adverse pregnancy and birthing outcomes. First Nations mothers are 3–5 times more likely than other mothers to experience maternal mortality; babies are 2–3 times more likely to be born preterm, low birth wei...

Aim Estimation of end-tidal carbon dioxide (EtCO2) with capnography can guide mask ventilation in infants born at less than 30 weeks of gestation. Chemical sensitive colorimetric devices to detect CO2 are widely used at resuscitation. We aimed to quantify EtCO2 in the first breaths following initiation of mask ventilation at birth and correlated ne...

Introduction In neonatal resuscitation, T-piece resuscitator (TPR) are used widely, but the evidence is limited for their use in infants born at term gestation. The aim of this study was to compare the delivered positive end expiratory pressure (PEEP) and respiratory system resistance ( R rs) using TPR and self-inflating bag (SIB) in a cadaveric pi...

For the care of neonatal infants, abdominal auscultation is considered a safe, convenient, and inexpensive method to monitor bowel conditions. With the help of early automated detection of bowel dysfunction, neonatologists could create a diagnosis plan for early intervention. In this paper, a novel technique is proposed for automated peristalsis so...

A firm concept of time is essential for establishing causality in a clinical setting. Review of critical incidents and generation of study hypotheses require a robust understanding of the sequence of events but conducting such work can be problematic when timestamps are recorded by independent and unsynchronized clocks. Most clinical models implici...

Purpose In 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 (Rrs) using TPR and self-inflating bag (SIB) in a cadaveric piglet mod...

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...

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...

Purpose Newborn 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 Austr...

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...

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...

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...

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)...

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...

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...

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...

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...

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...

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 (...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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,...

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...

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...

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...

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...

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...

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...

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...

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...

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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...

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...

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...

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...

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...

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.

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...

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...