PubMed Health⌕ Search

Biomedical subjects

D J Henderson-Smart

Publications and source records attributed to D J Henderson-Smart.

At least 73 records · Page 4Linked to original sources
PubMed1997

Delayed umbilical cord clamping in preterm infants: a feasibility study.

OBJECTIVES: To assess: (i) the size of placental transfusion following a 30 s delay in cord clamping following vaginal and Caesarean births; and (ii) the feasibility of delaying cord clamping in the labour ward and particularly in the operating theatre. METHODS: Fourty-six infants born at 26-33 weeks gestation were randomized to having the umbilical cord clamped either immediately or 30 s after birth. The venous haematocrit was measured at 1 and at 4 h of age. RESULTS: There were trends towards higher mean haematocrits in the infants following delayed clamping, but these were not significant either at 1 h (55 +/- 7.7 vs 52.9 +/- 7) or at 4 h of age (55 +/- 7 vs 52.5 +/- 7). The trends were more marked in the infants born by Caesarean section, and in those born at 26-29 weeks gestation. CONCLUSIONS: A 30 s delay in cord clamping is feasible at both vaginal and Caesarean births, but does not lead to the predicted difference in infant haematocrit. Although physiological studies suggest that a placental transfusion of 15-20 mL/kg occurs within 30 s of delivery, these data suggest that future trials should either delay cord clamping for more than 30 s, or should alter the position of the infant in relation to the uterus in order to facilitate the transfusion. Delayed cord clamping is feasible at Caesarean section.

Blood Transfusion, Intrauterine↗
PubMed1997

Incidence of apnoea and bradycardia in preterm infants following DTPw and Hib immunization: a prospective study.

OBJECTIVE: To evaluate the incidence and severity of apnoea and bradycardia in hospitalized preterm infants following immunization at 2 months of age, and identify risk factors. METHODOLOGY: A prospective study of 98 preterm infants, of gestational age 24-31 weeks, immunized at approximately 2 months post natal age with diphtheria-tetanus-whole cell pertussis vaccine (DTPw) in the neonatal intensive care unit (NICU) at King George V Hospital Sydney. Half the infants also received Haemophilus influenzae type b conjugate vaccine (Hib) simultaneously. All infants were monitored for apnoea and bradycardia in the 24 h periods pre- and post immunization. RESULTS: Only one infant had apnoea and/or bradycardia pre-immunization compared with 17 post immunization. For 12 infants these events were brief, self-limiting and not associated with desaturations (oxygen saturation < 90%). However, for five infants (30%) these events were associated with oxygen desaturation and two of these infants required supplemental oxygen. The group that had apnoea and/or bradycardia and the group that did not were not significantly different in terms of gestational age, birth weight and other variables. Infants who received Hib together with DTPw were less likely to have apnoea and/or bradycardia than those given DTPw alone. CONCLUSION: When considering immunization for preterm infants, the benefits of early immunization must be balanced against the risk of apnoea and bradycardia. We recommend that the cardio-respiratory function of hospitalized infants born at less than 31 weeks gestation be monitored for 48 h post immunization.

Apnea↗
PubMed1997

Elective high-frequency oscillatory ventilation versus conventional ventilation in preterm infants with pulmonary dysfunction: systematic review and meta-analyses.

OBJECTIVES: To systematically review the evidence to determine whether the routine use of high-frequency oscillatory ventilation (HFOV) as compared with conventional ventilation (CV) is beneficial or harmful in preterm infants requiring mechanical ventilation for pulmonary failure principally due to respiratory distress syndrome. METHODS: All randomized controlled trials of elective HFOV versus CV in preterm infants <36 weeks' gestation with respiratory failure mainly attributable to respiratory distress syndrome were identified from the literature through a search of MEDLINE, EMBASE, Oxford database of Perinatal trials, and previous reviews including cross-references and abstracts. Meta-analyses using event rate ratios (ERR), event rate difference, and if significant, number needed-to-treat were calculated (95% confidence limits were used for all analyses). Two prespecified subgroup analyses were performed. RESULTS: Four published trials were included. Meta-analyses revealed the following ERR (95% confidence intervals) for HFOV versus CV: mortality at 28 to 30 days, 1.02 (0.76, 1.39); chronic lung disease (CLD) at 28 days, 0.86 (0.73, 1.01); mortality or CLD, 0.9 (0.80, 1. 01); air-leak syndromes, 1.13 (0.97, 1.33); mechanical ventilation at 28 days, 1.06 (0.84, 1.33); supplemental oxygen at discharge, 0. 59 (0.37, 0.92); intraventricular hemorrhage (IVH) all grades, 1.11 (0.95, 1.29); IVH (grades 3 or 4), 1.32 (1.01, 1.72); and periventricular leukomalacia, 1.39 (0.91, 2.13). In the subgroup of trials in which a high volume strategy (HVS) was used the ERR for CLD was 0.53 (0.36, 0.78); mortality or CLD, 0.56 (0.40, 0.77); supplemental oxygen at discharge, 0.57 (0.36, 0.92); IVH (all grades), 0.90 (0.61, 1.33); and IVH (grades 3 or 4), 0.84 (0.39, 1. 84). Results were similar to these for the trials using surfactant. One recent trial suggests that HFOV may reduce the cost of in-hospital care. CONCLUSIONS: The overall meta-analysis is dominated by the HIFI study, which was criticized for its methodology and surfactant was not used. Subsequent studies, most of which used HVS and/or surfactant, have shown benefits in measures of CLD without an increase in rates of IVH. Caution is warranted in interpreting these results because: 1) the treatment is not blinded and this could affect some outcomes; 2) except for one small trial postneonatal survival, lung function, and neurodevelopment have not been reported from HVS trials; and 3) the benefits and disadvantages have not been reported in infants born at different gestational ages or different birth weights. Importantly, results from groups experienced in the use of HFOV may not be readily generalizable.

Barotrauma↗
PubMed1996

The characteristics and frequency of augmented breaths during CO2-induced hyperpnoea of newborn infants.

1. Hypercapnic ventilatory responses of thirty-five full term infants aged 1-7 days were evaluated, and the characteristics and incidence of augmented breaths were determined. 2. According to the inspiratory airflow profile and tidal volume (VT), augmented breaths were categorized as 'type A' (biphasic, VT > or = 2 x control VT), or 'type M' (multiphasic, VT < 2 x control VT). 3. Steady-state inhalation of 2-4% CO2 resulted in a 3-fold increase in the frequency of augmented breaths after 8 min; 80 s rebreathing a mixture containing 5-6% CO2 resulted in a 20-fold increase in the frequency of these breaths. 4. During eupnoea, 85% of spontaneously occurring augmented breaths were type A. With increasing respiratory drive, there was a disproportionate increase in type M compared with type A breaths: after 80 s rebreathing, 86% of augmented breaths were type M and only 14% were type A. 5. These findings indicate that the hypercapnic hyperpnoea facilitates an inspiration-augmenting reflex in newborn infants. The significance of type M breaths is unclear; they appear to be characteristic of the newborn, and may represent the response of an immature respiratory system to load.

Carbon Dioxide↗
PubMed1996

Competency-based learning in neonatology.

An educational model integrating structured teaching with clinical experience, or clerkship, has been designed to enable students to learn the core knowledge, skills and attitudes necessary to care for the newborn. The programme is run for fifth year medical students as part of four, 9-week periods in Obstetrics and Gynaecology each year. A SCORPIO teaching session is held in week 1 to introduce students to the core competencies in the subject areas of newborn examination, breastfeeding, resuscitation, respiratory distress and anthropometry. Groups of four students rotate through each topic, which is conducted by a neonatologist or registrar in training. Eight problem-based learning sessions are held during weeks 2-9. Several students assess a clinical problem, identify learning issues and meet colleagues and a facilitator to share their learning experiences and resolve the problem. The clinical experience, or clerkship, is based in the neonatal nursery where 2-3 students spend a week consolidating their clinical and procedural skills. A study group was assessed at the end of the programme by an Objective Structured Clinical Examination (OSCE) and a Multiple Choice Questionnaire (MCQ). A control group did the same assessment in week 1. All students were asked to rate the educational value of the three learning methods on a 5-point Likert scale. The study group (n = 20) achieved a mean composite mark of 66% (SD 10%). This was significantly higher (P < 0.001) than that of the control group (n = 18), mean 45% (SD 7%). All students (100%) rated the educational value of SCORPIO as high or very high, and the comparative rating for problem-based learning and clerkship was 65%, respectively. The programme was enthusiastically received by the students and resulted in mastery of a range of core competencies necessary for care of the newborn.

Australia↗
PubMed1996

Chest radiograph abnormalities in very low birthweight survivors of chronic neonatal lung disease.

OBJECTIVE: To determine whether the neonatal chest radiograph (CXR) at 28 days in very low birthweight (VLBW) infants who develop chronic neonatal lung disease (CNLD) predicts oxygen therapy duration or CXR abnormalities in early childhood. Also, to assess the inter-observer reliability of the radiologists scoring the CXR. METHODOLOGY: Clinically well survivors of CNLD (n = 46) had neonatal CXR scored (mean age 28.5 days) and compared with current CXR (mean age 40 months). The CXR were scored independently and 'blindly' by two paediatric radiologists using a standardized scoring system (range 0-10). RESULTS: There was no correlation between neonatal CXR scores and current CXR scores for either radiologist. There was no association between CXR severity scores and duration of oxygen therapy for either neonatal or current CXR. Radiologist A scored the current CXR significantly more abnormal than radiologist B [medians (range): 3 (1-6) vs 1 (0-5), P < 0.001] with reasonable correlation (r = 0.593, P < 0.005) but worse than chance agreement (kappa = -0.034). The median scores for the neonatal CXR were similar [1.5 (0-8) vs 2 (0-8), P = 0.789] and again there was good correlation (r = 0.760, P < 0.0005) although poor individual agreement (kappa = 0.243) between radiologists. CONCLUSIONS: Follow-up CXR abnormalities in VLBW infants with CNLD are usually minor and are not predictive of the duration of oxygen therapy that will be required nor of the CXR appearance in early childhood. Considerable inter-observer variation exists in the interpretation of the CXR in CNLD.

Bronchopulmonary Dysplasia↗
PubMed1996

The effect of temperature on the ventilatory response to carbon dioxide in the neonatal rat.

The rectal temperature of newborn rats in the nest varies between 32 and 39 degrees C, depending on environmental temperature and the presence of the dam. Because rebreathing of CO2 occurs in the nest, experiments were carried out to examine the effects of body temperature on the ventilatory response (VR) to CO2 at different postnatal ages. The VR to 2 and 4% carbon dioxide was examined in rat pups by the body plethysmograph method whereas rectal temperature was manipulated to 32-33 degrees C, 36-37 degrees C, and 38-39 degrees C. At three different ages, 2-3 d, 5-6 d, and 8-9 d, rat pups had a VR to both concentrations of CO2 due, principally, to an increase in tidal volume (Vt). Ventilation (Vi) in air was highest at the lowest rectal temperature, and there was a significant, inverse correlation with temperature in the 2-3-d-old and 5-6-d-old rats. The VRs to 2 and 4% CO2 were significantly, inversely, related to body temperature in the youngest group. The direction of temperature modification also had a significant effect, because VRs to both 2 and 4% CO2 were significantly lower in rat pups which were being warmed compared with those being cooled.

Analysis of Variance↗
PubMed1995

Maternal and neonatal outcome of patients classified according to the Australasian Society for the Study of Hypertension in Pregnancy Consensus Statement.

OBJECTIVE: To outline the maternal and perinatal features and outcome of patients referred to a tertiary referral obstetric hospital for management of their hypertension. SETTING AND PATIENTS: 205 consecutive public patients admitted for assessment of hypertension (either full admission or day-stay) to King George V Hospital's Hypertension in Pregnancy Unit, between February 1993 and January 1994. DESIGN: A prospective study in which patients were classified according to the Australasian Society for the Study of Hypertension in Pregnancy (ASSHP) Consensus Statement classification. RESULTS: Of the 205 patients, 25% did not meet the criteria for pre-eclampsia or chronic hypertension, 33% had mild pre-eclampsia, 34% had severe pre-eclampsia and the remainder had chronic hypertension. The mean gestation at delivery for those with mild pre-eclampsia was 38.3 weeks and for severe pre-eclampsia 35.3 weeks. For the mild and severe groups respectively, the rate of elective delivery for raised blood pressure was 56% and 53%; for caesarean section, 17% and 61%; and for perinatal death, 2% and 4%. In the severe group, 49% had fetal problems and 25% required intravenous antihypertensives. CONCLUSIONS: The multisystem nature of pre-eclampsia makes comparison of management protocols difficult. Ongoing audit is needed of maternal and perinatal outcomes and features of disease in patients with hypertension in pregnancy under a universal classification. The ASSHP classification system successfully identifies patients who require more intensive management and intervention.

Chronic Disease↗
PubMed1995

A neonatal early discharge and home support programme: shifting care into the community.

OBJECTIVE: The Neonatal Early Discharge and Family Support Programme (NEDP) was an initiative aimed at providing extended care for families whose infants had required neonatal special care, thereby allowing earlier discharge. METHODOLOGY: Two groups of families were examined; one before and one after the instigation of the NEDP. Hospital and community service usage and psychosocial effects were examined. RESULTS: Families who received support were able to be discharged earlier and rooming-in was unnecessary as support was provided at home. Visits to family doctors for mothercraft issues were less frequent. Transport of babies from the Level 3 nursery to other nurseries in order to be closer to home was also provided by the nursing team, saving on ambulance costs and freeing their time for emergencies. There was no increase in maternal anxiety and infants were less difficult in the patient group. CONCLUSIONS: NEDP and family support programme is a worthwhile extension of neonatal intensive care.

Case-Control Studies↗
PubMed1994

Brainstem auditory evoked response development in preterm and term baboons (Papio hamadryas).

Brainstem auditory evoked responses were recorded longitudinally from 11 neonatal baboons (Papio hamadryas), 6 of which were preterm. Recordings were made in unsedated animals from day 161 to day 362 after conception (term = 182 days). The pattern of development of both waveform morphology and of wave latency was consistent with that seen in the human neonate, with a rapid maturation of the response during the perinatal period, and then a slower development to adult values. Brainstem conduction time was measured from the wave I to wave IV interval, and this demonstrated a similar pattern, with a rapid decrease in latency up to term, and then decreasing more slowly to reach adult values by 4 months of age in the baboon.

Aging↗
PubMed1994

The reproducibility of the response of the human newborn to CO2 measured by rebreathing and steady-state methods.

The ventilatory response (VR) of the full-term newborn to CO2 was studied during quiet sleep using rebreathing and steady-state methods. Rebreathing responses were obtained under normoxic (fractional inspired oxygen concentration, Fi,O2 = 0.21) and hyperoxic (Fi,O2 = 0.4) conditions. Ten infants were tested three to five times using each of the two rebreathing protocols and the results averaged. Overall, there was no significant difference between either the mean variability (coefficient of variation) or slope of the VR measured under normoxic and hyperoxic conditions. Four infants were studied using a steady-state technique. There was marked test-to-test variability in VRs measured by this method. The results appear to indicate that the variability of the VR of the newborn to CO2 is not a result of chemoreflex changes in ventilation elicited in response to fluctuations in arterial PO2.

Behavior↗
PubMed1994

Predictive value of umbilical artery pH in preterm infants.

Compared with term infants, little information is available about the usefulness of the umbilical artery pH in relation to outcome in extremely preterm infants. This prospective study evaluates the relation between umbilical artery pH (UapH), Apgar scores, perinatal events, and outcome in infants born at less than 32 weeks' gestation. Six hundred and twenty three infants of < 32 weeks' gestation were studied. The median UapH was 7.25, with a range of 6.78-7.49. A low UapH was significantly associated with male sex, hyaline membrane disease, grade 3 or 4 intraventricular haemorrhage, and neonatal death. It was also associated with lower birth weight and lower birthweight centile. The relations between the UapH and outcomes of neonatal death, cerebral palsy, and developmental quotient at 1 year, and other perinatal risk factors were then examined using multiple logistic regression. After adjusting for other risk factors, UapH was not significantly associated with any outcome. In contrast, a low one minute Apgar (< 4) remained a significant risk factor, with odds ratios of 2.7 (95% confidence interval (CI) 1.5 to 5.2) for neonatal death and 3.8 (95% CI 1.4 to 10.4) for cerebral palsy.

Apgar Score↗
PubMed1992

A review of chest physiotherapy in neonatal intensive care units in Australia.

Clinical techniques and protocols for chest physiotherapy vary greatly from one Neonatal Intensive Care Unit to another. In 1988 a questionnaire designed to investigate differing techniques used was distributed to Neonatal Intensive Care Units (NICU) around Australia. Fourteen of the 15 questionnaires were completed and returned. The results revealed that the methods of chest treatment and the indicators for commencing chest treatment were similar throughout NICU. Both physiotherapists and nursing staff played a role in the performance of chest treatment in all but one unit where it was the responsibility of nursing staff. However, the area in which there was most variability between NICU was the individual treatment protocols employed pre- and postextubation of the neonate. A review of literature over the past 10 years also demonstrates variability in chest physiotherapy. It was concluded that further well-controlled studies with larger sample sizes are needed to validate the use of chest physiotherapy for the neonate, especially in relation to the techniques and specific protocols employed.

Australia↗