Biomedical subjects

D Henderson-Smart

Publications and source records attributed to D Henderson-Smart.

At least 19 recordsLinked to original sources

PubMed2006

Prenatal predictors of mortality in very preterm infants cared for in the Australian and New Zealand Neonatal Network.

AIM: To identify antenatal and perinatal risk factors for in-hospital mortality of babies born within the Australian and New Zealand Neonatal Network (ANZNN). METHODS: Data were collected prospectively as part of the ongoing audit of high-risk infants (birth weight <1500 g or gestation <32 weeks) admitted to all level III neonatal units in Australia and New Zealand. Antenatal and intrapartum factors to 1 min of age were examined in 11 498 infants with gestational age >24 weeks. Risk and protective factors for mortality were derived from logistic regression models fitted to 1998-9 data and validated on 2000-1 data. RESULTS: For the whole cohort of infants born between 1998 and 2001, prematurity was the dominant risk factor, infants born at 25 weeks having 32 times greater odds of death than infants born at 31 weeks. Low birth weight for gestational age also had a dose-response effect: the more growth restricted the infant the greater the risk of mortality; infants below the 3rd centile had eight times greater odds of death than those between the 25th and 75th centiles. Male sex was also a significant risk factor (odds ratio (OR) 1.55, 95% confidence interval (CI) 1.31 to 1.82). Maternal hypertension in pregnancy was protective (OR 0.46, 95% CI 0.36 to 0.50). The predictive model for mortality had an area under the receiver operating characteristic curve of 0.82. CONCLUSIONS: Risk of mortality can be predicted with good accuracy with factors up to the 1 min Apgar score. By using gestation rather than birth weight as the main indicator of maturity, these data confirm that weight for gestational age is an independent risk factor for mortality.

Australasia↗

PubMed2005

Altered dietary salt for preventing pre-eclampsia, and its complications.

BACKGROUND: In the past, women have been advised that lowering their salt intake might reduce their risk of developing pre-eclampsia. Although this practice has largely ceased, it remains important to assess the evidence about possible effects of altered dietary salt intake during pregnancy. OBJECTIVES: The objective of this review was to assess the effects of altered dietary salt during pregnancy on the risk of developing pre-eclampsia and its complications. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group Trials Register (8 April 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1, 2005), and EMBASE (2002 to May 2005). SELECTION CRITERIA: Randomised trials evaluating either reduced or increased dietary salt intake during pregnancy. DATA COLLECTION AND ANALYSIS: Two review authors selected trials for inclusion and extracted data independently. Data were entered on Review Manager software for analysis, and double-checked for accuracy. MAIN RESULTS: Two trials were included, with 603 women. Both compared advice to reduce dietary salt intake with advice to continue a normal diet. The confidence intervals were wide and crossed the no-effect line for all the reported outcomes, including pre-eclampsia (relative risk 1.11, 95% confidence interval 0.46 to 2.66). In other words, there was insufficient evidence for reliable conclusions about the effects of advice to reduce dietary salt. AUTHORS' CONCLUSIONS: In the absence of evidence that advice to alter salt intake during pregnancy has any beneficial effect for prevention of pre-eclampsia or any other outcome, salt consumption during pregnancy should remain a matter of personal preference.

Diet, Sodium-Restricted↗

PubMed2004

Doxapram treatment for apnea in preterm infants.

BACKGROUND: Recurrent apnea is common in preterm infants, particularly at very early gestational ages. These episodes of loss of effective breathing can lead to hypoxemia and bradycardia which may be severe enough to require resuscitation including use of positive pressure ventilation. Doxapram has been used to stimulate breathing and so prevent apnea and its consequences. OBJECTIVES: In preterm infants with recurrent apnea, does treatment with Doxapram lead to a clinically important reduction in apnea and use of intermittent positive airways pressure (IPPV), without clinically important side effects? SEARCH STRATEGY: Searches were made of the Oxford Database of Perinatal trials, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2004), MEDLINE from 1966 - June 2004, EMBASE from 1980 - June 2001, CINAHL from 1982- June 2004. Text words 'doxapram', 'apnea or apnoea' and the MeSH term 'infant, premature' were used. Previous reviews including cross references, abstracts from conferences and symposia proceedings were also examined. Abstracts of the Society for Pediatric Research were searched from 1996 - 2004 inclusive. SELECTION CRITERIA: All trials utilising random or quasi-random patient allocation, in which doxapram was used for the treatment of apnea in preterm infants were included. DATA COLLECTION AND ANALYSIS: Each author evaluated the papers for quality and inclusion criteria. Independent data extraction was carried out. MAIN RESULTS: Only one trial, which randomized 11 infants to intravenous doxapram and 10 infants to placebo, was found. There were fewer treatment failures after 48 hours in the group of preterm infants treated with doxapram (4/11) compared with the group treated with placebo (8/10). The wide confidence intervals made this result non-significant [RR 0.45 (0.20, 1.05)]. Only one infant, who was from the placebo group, was given IPPV. Of the seven responders by 48 hours in the group of 11 who received doxapram, five failed to respond between 48 hours and seven days after commencement of therapy. This gives a late failure rate of 9/11, similar to the short term failure rate in the placebo group of 8/10. It is not possible to evaluate the late responses of all those in the placebo group since they crossed over to a treatment arm. REVIEWERS' CONCLUSIONS: Although intravenous Doxapram might reduce apnea within the first 48 hours of treatment, there are insufficient data to evaluate the precision of this result or to assess potential adverse effects. No long term outcomes have been measured. Further studies are needed to determine the role of this treatment in clinical practice.

Aminophylline↗

PubMed2004

High dose caffeine citrate for extubation of preterm infants: a randomised controlled trial.

OBJECTIVE: To compare two dosing regimens for caffeine citrate in the periextubation period for neonates born at less than 30 weeks gestation in terms of successful extubation and adverse effects. DESIGN: A multicentre, randomised, double blind, clinical trial. SETTING: Four tertiary neonatal units within Australia. PATIENTS: Infants born less than 30 weeks gestation ventilated for more than 48 hours. INTERVENTIONS: Two dosing regimens of caffeine citrate (20 v 5 mg/kg/day) for periextubation management. Treatment started 24 hours before a planned extubation or within six hours of an unplanned extubation. MAIN OUTCOME MEASURE: Failure to extubate within 48 hours of caffeine loading or reintubation and ventilation or doxapram within seven days of caffeine loading. RESULTS: A total of 234 neonates were enrolled. A significant reduction in failure to extubate was shown for the 20 mg/kg/day dosing group (15.0% v 29.8%; relative risk 0.51; 95% confidence interval (CI) 0.31 to 0.85; number needed to treat 7 (95% CI 4 to 24)). A significant difference in duration of mechanical ventilation was shown for infants of less than 28 weeks gestation receiving the high dose of caffeine (mean (SD) days 14.4 (11.1) v 22.1 (17.1); p = 0.01). No difference in adverse effects was detected in terms of mortality, major neonatal morbidity, death, or severe disability or general quotient at 12 months. CONCLUSIONS: This trial shows short term benefits for a 20 mg/kg/day dosing regimen of caffeine citrate for neonates born at less than 30 weeks gestation in the periextubation period, without evidence of harm in the first year of life.

Caffeine↗

PubMed2003

Magnesium sulphate versus diazepam for eclampsia.

BACKGROUND: Eclampsia, the occurrence of a convulsion in association with pre-eclampsia, remains a rare but serious complication of pregnancy. A number of different anticonvulsants are used to control eclamptic fits and to prevent further fits. OBJECTIVES: The objective of this review was to assess the effects of magnesium sulphate compared with diazepam when used for the care of women with eclampsia. Magnesium sulphate is compared with phenytoin and with lytic cocktail in other Cochrane reviews. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth trials register (28 November 2002) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4, 2002). SELECTION CRITERIA: Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with diazepam for women with a clinical diagnosis of eclampsia. DATA COLLECTION AND ANALYSIS: Both reviewers assessed and extracted data. MAIN RESULTS: Seven trials involving 1441 women are included. Most of the data are from trials of good quality. Magnesium sulphate is associated with a reduction in maternal death when compared to diazepam (six trials 1336 women; relative risk (RR) 0.59, 95% confidence interval (CI) 0.37 to 0.94). There is also a substantial reduction in the risk recurrence of further fits (seven trials 1441 women; RR 0.44, 95% CI 0.34 to 0.57). There were few differences in any other measures of outcome, except for fewer Apgar scores less than seven at five minutes (two trials 597 babies; RR 0.72, 95% CI 0.55 to 0.94) and fewer babies with a length of stay in special care baby unit more than seven days (three trials 631 babies; RR 0.66, 95% CI 0.46 to 0.95) associated with magnesium sulphate. REVIEWER'S CONCLUSIONS: Magnesium sulphate appears to be substantially more effective than diazepam for treatment of eclampsia.

Anticonvulsants↗

PubMed2001

Antiplatelet drugs for prevention of pre-eclampsia and its consequences: systematic review.

OBJECTIVE: To assess the effectiveness and safety of antiplatelet drugs for prevention of pre-eclampsia and its consequences. DESIGN: Systematic review. DATA SOURCES: Register of trials maintained by Cochrane Pregnancy and Childbirth Group, Cochrane Controlled Trials Register, and Embase. INCLUDED STUDIES: Randomised trials involving women at risk of pre-eclampsia, and its complications, allocated to antiplatelet drug(s) versus placebo or no antiplatelet drug. MAIN OUTCOME MEASURES: Pre-eclampsia, preterm birth, fetal or neonatal death, and small for gestational age baby. Studies were assessed for quality of concealment of allocation and losses to follow up. RESULTS: 39 trials (30 563 women) were included, and 45 trials (>3000 women) excluded. Use of antiplatelet drugs was associated with a 15% reduction in the risk of pre-eclampsia (32 trials, 29 331 women; relative risk 0.85, 95% confidence interval 0.78 to 0.92; number needed to treat 100, 59 to 167). There was also an 8% reduction in the risk of preterm birth (23 trials, 28 268 women; 0.92, 0.88 to 0.97; 72, 44 to 200), and a 14% reduction in the risk of fetal or neonatal death (30 trials, 30 093 women; 0.86, 0.75 to 0.98; 250, 125 to >10 000) for women allocated antiplatelet drugs. Small for gestational age babies were reported in 25 trials (20 349 women), with no overall difference between the groups (relative risk 0.92, 0.84 to 1.01). There were no significant differences in other measures of outcome. CONCLUSIONS: Antiplatelet drugs, largely low dose aspirin, have small to moderate benefits when used for prevention of pre-eclampsia.

Aspirin↗

PubMed2001

Differences and trends in obstetric interventions at term among urban and rural women in New South Wales: 1990-1997.

The aim of this study was to compare the management of term births among rural and urban women, including the effect of indigenous status and out-of-area-birth for rural women. Data were obtained from the NSW Midwives Data Collection (MDC), on 619,298 women who gave birth to a live, singleton infant at term (37-45 weeks gestation) from 1 January 1990 to 31 December 1997. Compared with urban non-indigenous women, rural women and indigenous women had lower rates of obstetric interventions both before birth (induction of labour, planned Caesarean section and epidural) and at the time of birth (Caesarean after labour, instrumental delivery and episiotomy). This was especially true for rural women giving birth in the their local area. The differing pregnancy risk profile of rural women did not explain the differences in intervention rates but differences were partly explained by higher rates of epidural anaesthesia in urban areas.

Adult↗

PubMed2001

Recent advances in the design and performance of research assistants.

Every laboratory needs personnel who work 24 hours a day 7 days a week, are efficient, obedient, capable of showing initiative, insightful and affable. Our experience of laboratory workers tells us that there is an immense way to go to achieve these goals. Having tired of the normal, Darwinian approach, a project has been initiated to achieve these ends through genetic technologies.

Humans↗

PubMed2000

Magnesium sulphate versus diazepam for eclampsia.

BACKGROUND: A number of different anticonvulsants are used to control eclamptic fits and to prevent future seizures. OBJECTIVES: The objective of this review was to assess the effects of magnesium sulphate compared with diazepam when used for the care of women with eclampsia. Magnesium sulphate is compared with phenytoin and with lytic cocktail (in preparation) in other Cochrane reviews. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth trials register and the Cochrane Controlled Trials Register, 1999 Issue 3. SELECTION CRITERIA: Randomised trials comparing magnesium sulphate (intravenous or intramuscular administration) with diazepam for women with a clinical diagnosis of eclampsia. DATA COLLECTION AND ANALYSIS: Trial quality was assessed and data extraction was done by the two reviewers. MAIN RESULTS: Five trials involving 1236 women were included. Most of these trials were of good quality. Magnesium sulphate was associated with a substantial reduction in the recurrence of convulsions, when compared to diazepam (relative risk 0.45, 95% confidence interval 0.35 to 0.58). Maternal mortality was also reduced, although this difference was borderline for statistical significance (relative risk 0.60, 95% CI 0.36-1.00). There are no differences in any other measures of outcome, except for fewer Apgar scores <7 at five minutes (relative risk 0.72, 95% CI 0.55-0.94) and in length of stay in SCBU >7 days (relative risk 0. 66, 95% CI 0.46-0.95) associated with magnesium sulphate. REVIEWER'S CONCLUSIONS: Magnesium sulphate appears to be substantially more effective than diazepam for treatment of eclampsia.

Anticonvulsants↗

PubMed2000

Reduced salt intake compared to normal dietary salt, or high intake, in pregnancy.

BACKGROUND: In the past women have been advised that lowering their salt intake might reduce their risk of pre-eclampsia. Although this practice has largely ceased, it remains important to assess the evidence about possible effects of advice to alter dietary salt intake during pregnancy. OBJECTIVES: The objective of this review was to assess the effects of dietary advice to alter salt intake compared to continuing a normal diet, on the risk of pre-eclampsia and its consequences. SEARCH STRATEGY: We searched the register of trials maintained and updated by the Cochrane Pregnancy and Childbirth Group, and the Cochrane Controlled Trials Register Disc Issue 4, 1998. SELECTION CRITERIA: Studies were included if they were randomised trials of advice to either reduce or to increase dietary salt during pregnancy. DATA COLLECTION AND ANALYSIS: All data were extracted independently by both reviewers. MAIN RESULTS: Two trials were included, with 603 women. They compared advice about a low salt diet with no dietary advice. The confidence intervals for all of the outcomes reported were wide, and cross the no effect line. This includes pre-eclampsia (relative risk 1.11, 95% confidence interval 0.46 to 2.66). Even when taken together, these trials are insufficient to provide reliable information about the effects of advice on salt restriction during normal pregnancy. None of the trials included women with pre-eclampsia, so this review provides no reliable information about changes in salt intake for treatment of pre-eclampsia. REVIEWER'S CONCLUSIONS: Salt consumption during pregnancy should remain a matter of personal preference.

Female↗

PubMed2000

Antenatal transfer of rural women to perinatal centres. High Risk Obstetric and Perinatal Advisory Working Group.

The aim of this study was to describe antenatal transfers of rural women to perinatal centres, and among transferred women, to assess the use of selected evidence-based therapies and determine the predictors of preterm and imminent births. The clinical records of rural women antenatally transferred to perinatal centres in NSW and the ACT during 1997-1998 were reviewed. Of 453 rural antenatal transfers, 408 (90%) were emergency transfers. Increasing remoteness was associated with increased rates of antenatal transfer but not with a lower probability of giving birth. Of all transferred women, 64% delivered; 58% of preterm transfers delivered preterm and of those delivering preterm, 76% delivered within 7 days. Although the main reason for antenatal transfer was the possibility of preterm birth, women presenting with preterm contractions only were less likely to deliver preterm (OR = 0.2, 95% CI 0.1-0.4) or < or = 7 days (OR = 0.3, 95% CI 0.2-0.5) than women with any other presenting symptoms. The overall usage of effective interventions (antenatal steroids, antibiotics for PPROM and beta-mimetic tocolysis to delay birth) among antenatally transferred rural women was high, but there is room for increased uptake prior to transfer.

Adult↗

PubMed2000

Term breech birth in New South Wales, 1990-1997.

Data on 636,708 women delivering a singleton infant of gestational age > or =37 weeks in NSW from 1 January 1990 to 31 December 1997 were used to examine trends in breech births at term and the mode of delivery. From 1990 to 1997, although the crude rate of breech births at term remained stable at 3.4%, the adjusted odds ratio for breech birth compared with cephalic birth decreased over time. Among live breech births, the crude rate of vaginal breech birth declined from 29.4% to 19.7%, with an attendant increase in elective Caesarean sections from 49.1% to 58.4%. Most of this increase was at 38 and 39 weeks gestation. There was no change in the perinatal mortality rate among breech births during the study period. Despite increasing maternal age, the adjusted odds of a breech birth at term decreased over time. This could be due to offsetting factors, such as increased use of external cephalic version. If the decrease in vaginal breech birth continues, it may lead to the skills for this procedure being lost.

Adult↗

PubMed1999

Small fetal size: a risk factor for breech birth at term.

OBJECTIVE: To examine fetal size as a risk factor for breech birth at term. METHODS: Singleton breech or cephalic births of gestational age > or = 37 weeks in New South Wales (NSW), Australia from 1990 to 1996 were analyzed. Birthweight percentile was used as a measure of fetal size at the time of birth. Factors associated with breech birth at term were analyzed using logistic regression. RESULTS: There were 18914 singleton breech and 540164 cephalic births in the study period. The important independent predictors of breech birth at term were advancing maternal age, primiparity, female sex and small size for gestational age. Infants < 10th percentile had an adjusted odds ratio of 1.33 (95% CI 1.28-1.38) for breech birth at term compared with 25th-75th percentile infants. CONCLUSIONS: Breech birth at term was associated with smaller fetal size for gestational age. This was shown directly through an association with birthweight-for-gestational-age percentiles and indirectly through association with female sex, primiparous birth and congenital anomalies.

Adult↗

PubMed1999

Trends in births at and beyond term: evidence of a change?

OBJECTIVE: To examine trends in the distribution of births at and beyond term in New South Wales and in particular, to determine whether any changes are associated with changes in the obstetric practices of induction and elective caesarean section. DESIGN: Cross-sectional analytic study. SETTING: New South Wales, Australia. POPULATION: All 540,162 women delivering a singleton cephalic-presenting infant of gestational age > or = 37 weeks from 1 January 1990 to 31 December 1996. METHODS: Data were obtained from the New South Wales midwives data collection, a population-based surveillance system covering all births in New South Wales. The data were analysed to examine changes over time and associations between gestational age, maternal factors and onset of labour. MAIN OUTCOME MEASURES: Induction of labour and elective caesarean section rates. RESULTS: From 1990 to 1996 there was a significant decrease in births reported as 40 weeks of gestation, from 35,670 (46.3%) to 30,651 (40.3%). These declines were offset by significant increases in births at 38 and 39 weeks. Births > or = 42 weeks declined from 3321 (4.6%) to 2132 (2.8%). The decline in prolonged pregnancies was associated with increasing induction rates at 41 weeks. The re-distribution of some births from 40 to 38-39 weeks was associated with increasing rates of elective caesarean sections and induction at 38 and 39 weeks, and increasing maternal age. CONCLUSIONS: Clinicians appear to be implementing the recommendations of randomised controlled trials to offer induction after 41 weeks of gestation. However the trend of performing elective caesarean sections at earlier gestational ages may be unnecessarily putting some infants at increased risk of respiratory morbidity.

Adult↗

PubMed1999

Post-extubation prophylactic nasal continuous positive airway pressure in preterm infants: systematic review and meta-analysis.

OBJECTIVES: To determine whether management with nasal continuous positive airway pressure (NCPAP) in preterm infants having their endotracheal tube removed following a period of intermittent positive pressure ventilation (IPPV), leads to an increased proportion remaining free of additional ventilatory support, compared to extubation directly to headbox oxygen. METHODOLOGY: Search Strategy - Searches were made of the Oxford Database of Perinatal Trials, Medline, abstracts of conferences and symposia proceedings, expert informants, journal hand searching mainly in the English language and expert informant searches in the Japanese language. Selection criteria - All trials utilising random or quasi-random patient allocation, in which NCPAP (delivered by any method) was compared with headbox oxygen for postextubation care were included. Methodological quality was assessed independently by the two authors. Data collection and analysis - Data were extracted independently by the two authors. Meta-analysis using event rate ratios (ERRs) and event rate differences (ERDs) was performed using Revman 3.0 statistical software. Prespecified subgroup analysis to determine the impact of different levels of NCPAP and use of aminophylline were also performed using the same package. Similar analysis to investigate the effect of postnatal age on outcomes of interest was also undertaken. RESULTS: Nasal CPAP, when applied to preterm infants being extubated following IPPV, reduces the incidence of adverse clinical events (apnoea, respiratory acidosis and increased oxygen requirements) indicating the need for additional ventilatory support. This result is both statistically significant and clinically important; ERR, 0.62 (0.49, 0.79) and ERD, - 0.175 (- 0.256, - 0.095). A trend towards reduction in the incidence of oxygen dependency at 28 days of age is also seen in the group extubated to NCPAP; ERR, 0.86 (0.67, 1.10) and ERD, - 0.069 (- 0.177, 0.039). CONCLUSION: Nasal CPAP is effective in preventing failure of extubation in preterm infants following a period of endotracheal intubation and IPPV. Further definition of the patient gestational age and weight groups to whom these results apply is required. Optimal levels of NCPAP as well as methods of administration remain to be determined.

Aminophylline↗

PubMed1997

A comparison of the ventilatory response of sleeping newborn lambs to step and progressive hypoxaemia.

1. Slight variations in the rate at which hypoxaemia develops may significantly alter the ventilatory response (VR) elicited. Here we have developed a technique to compare the VRs elicited from sleeping newborn lambs by specific (step versus progressive), short-duration (< or = 5 min) episodes of hypoxaemia. The results may help us understand the limitations of using tests which deliver poorly defined stimuli to evaluate the postnatal development of the oxygen chemoreflex. 2. The VRs of five lambs elicited by a 5 min step or progressive reduction in the arterial oxygen saturation (Sa,O2) during quiet sleep were compared. Minute ventilation (V1, face mask) and Sa,O2 (pulse oximeter) were measured continuously. Alternate step (Sa,O2 reduced to 80-85% within 60 s and maintained for a further 4 min) and progressive tests (progressive reduction in Sa,O2 to 80% over 5 min) were administered daily between postnatal days 2-14. 3. There was a significant difference between the mean VR to step versus progressive hypoxaemia. The VR to a step challenge was biphasic (delta Vi = +32 +/- 5% at 1 min and -1 +/- 4% at 5 min; mean +/- S.E.M.). Progressive hypoxaemia elicited a more subdued but sustained hyperpnoea (delta Vi = +11 +/- 2% at 1 min and +11 +/- 4% at 5 min). The difference between these two response profiles was statistically significant (P < 0.001). 4. Mean responses of lambs aged < or = 5 days (4 +/- 0.2 days) and > or = 9 days (10 +/- 0.3 days) were also compared. There was an upward shift in the position of step and progressive response curves of older lambs, reflecting primarily the increased vigour of the initial hyperpnoea elicited by step (delta Vi at 1 min = +20 +/- 4% at 4 days vs. +40 +/- 11% at 10 days) as well as progressive (delta Vi at 1 min = +6 +/- 2% at 4 days vs. +17 +/- 5% at 10 days) hypoxaemia. 5. Qualitatively different VRs may be elicited from the newborn, depending upon the specific hypoxaemic profile administered. Therefore, to evaluate the significance of VRs elicited in response to classical, steady-state hypoxia at different postnatal ages properly, the stimulus must be accurately described.

Aging↗

PubMed1997

Ventilatory response of the newborn infant to mild hypoxia.

The transition from an immature (biphasic) to a mature (sustained hyperpneic) response to a brief period of sustained hypoxia is believed to be well advanced by postnatal day 10 for newborn infants. However, a review of the supporting evidence convinced us that this issue warranted further, more systematic investigation. Seven healthy term infants aged 2 days to 8 weeks were studied. The ventilatory response (VR) elicited by 5 min breathing of 15% O2 was measured during quiet sleep. Arterial SaO2 (pulse oximeter) and minute ventilation (expressed as a change from control, delta V'i) were measured continuously. Infants were wrapped in their usual bedding and slept in open cots at room temperature (23 degrees-25 degrees). Infants aged 2-3 days exhibited predominantely a sustained hypopnea during the period of hypoxia (delta V'i = -2% at 1 min, -13% at 5 min). At 8 weeks of age, the mean response was typically biphasic (delta V'i = +9% at 1 min, -4% at 5 min). This age-related difference between responses was statistically significant (two-way ANOVA by time and age-group; interaction P < 0.05). These data reveal that term infants studied under ambient conditions during defined quiet sleep may exhibit an immature VR to mild, sustained hypoxia for at least 2 months after birth. This suggests that postnatal development of the O2 chemoreflex is slower than previously thought.

Aging↗

PubMed1996

Improved outcomes following the introduction of surfactant to an Australian neonatal unit.

OBJECTIVE: To study the impact of the introduction of artificial surfactant therapy for hyaline membrane disease (HMD) in an Australian neonatal intensive care unit. METHODOLOGY: Infants < 32 weeks gestation admitted between June 1991 and Dec 1993 who received treatment with artificial surfactant were compared with infants admitted during the preceding 30 months who would have been candidates for such treatment. RESULTS: For treated infants with gestations in the range 24-27 weeks, there was a significant reduction in neonatal death (adjusted odds ratio 0.28) and a significant increase in the incidence of chronic lung disease (CLD) (adjusted odds ratio 3.4). With gestations in the range 28-31 weeks, there was no significant change in neonatal death or CLD, but there was a significant reduction in incidence of pneumothorax (adjusted odds ratio 0.32). CONCLUSIONS: A reduced incidence of pneumothorax and neonatal death following the introduction of artificial surfactant therapy was readily demonstrable in the Australian setting.

Australia↗