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Biomedical subjects

J L Peacock

Publications and source records attributed to J L Peacock.

At least 19 recordsLinked to original sources
PubMed2006

Randomised trial of high frequency oscillatory ventilation or conventional ventilation in babies of gestational age 28 weeks or less: respiratory and neurological outcomes at 2 years.

BACKGROUND: The long term outcome of children entered into neonatal trials of high frequency oscillatory ventilation (HFOV) or conventional ventilation (CV) has been rarely studied. OBJECTIVE: To evaluate respiratory and neurodevelopmental outcomes for children entered into the United Kingdom Oscillation Study, which was designed to evaluate these outcomes. METHODS: Surviving infants were followed until 2 years of age corrected for prematurity. Study forms were completed by local paediatricians at routine assessments, and parents were asked to complete a validated neurodevelopmental questionnaire. RESULTS: Paediatricians' forms were returned for 73% of the 585 surviving infants. Respiratory symptoms were common in all infants, and 41% had received inhaled medication. Mode of ventilation had no effect on frequency of any symptoms. At 24 months of age, severe neurodevelopmental disability was present in 9% and other disabilities in 38% of children, but the prevalence of disability was similar in children who received HFOV or CV (relative risk 0.93; 95% confidence interval 0.74 to 1.16). The prevalence of disability did not vary by gestational age, but boys were more likely to have overall disability. Developmental scores were unaffected by mode of ventilation (relative risk 1.13; 95% confidence interval 0.78 to 1.63) and were lower in infants born before 26 weeks gestation compared with babies born at 26-28 weeks. CONCLUSIONS: Initial mode of ventilation in very preterm infants has no impact on respiratory or neurodevelopmental morbidity at 2 years. HFOV and CV appear equally effective for the early treatment of respiratory distress syndrome.

Child Development↗
PubMed2006

Respiratory function of very prematurely born infants at follow up: influence of sex.

OBJECTIVE: To test the hypothesis that male compared with female prematurely born infants would have worse lung function at follow up. DESIGN: Prospective follow up study. SETTING: Tertiary neonatal intensive care units PATIENTS: Seventy six infants, mean (SD) gestational age 26.4 (1.5) weeks, from the United Kingdom oscillation study. INTERVENTIONS: Lung function measurements at a corrected age of 1 year. MAIN OUTCOME MEASURES: Airways resistance (Raw) and functional residual capacity (FRC(pleth)) measured by whole body plethysmography, specific conductance (sGaw) calculated from Raw and FRC(pleth), and FRC measured by a helium gas dilution technique (FRC(He)). RESULTS: The 42 male infants differed significantly from the 34 female infants in having a lower birth weight for gestation, requiring more days of ventilation, and a greater proportion being oxygen dependent at 36 weeks postmenstrual age and discharge. Furthermore, mean Raw and FRC(pleth) were significantly higher and mean sGaw significantly lower. After adjustment for birth and current size differences, the sex differences in FRC(pleth) and sGaw were 15% and 26% respectively and remained significant. CONCLUSION: Lung function at follow up of prematurely born infants is influenced by sex.

Airway Resistance↗
PubMed2005

Plethysmograph and interrupter resistance measurements in prematurely born young children.

BACKGROUND: Airways obstruction in premature infants is often assessed by plethysmography, which requires sedation. The interrupter (Rint) technique does not require sedation, but has rarely been examined in children under 2 years of age. OBJECTIVE: To compare Rint results with plethysmographic measurements of airway resistance (Raw) in prematurely born, young children. DESIGN: Prospective study. SETTING: Infant and Paediatric Lung Function Laboratories. PATIENTS: Thirty children with a median gestational age of 25-29 weeks and median postnatal age of 13 months. INTERVENTIONS AND MAIN OUTCOME MEASURES: The infants were sedated, airway resistance was measured by total body plethysmography (Raw), and Rint measurements were made using a MicroRint device. Further Raw and Rint measurements were made after salbutamol administration if the children remained asleep. RESULTS: Baseline measurements of Raw and Rint were obtained from 30 and 26 respectively of the children. Mean baseline Rint values were higher than mean baseline Raw results (3.45 v 2.84 kPa/l/s, p = 0.006). Limits of agreement for the mean difference between Rint and Raw were -1.52 to 2.74 kPa/l/s. Ten infants received salbutamol, after which the mean Rint result was 3.6 kPa/l/s and mean Raw was 3.1 kPa/l/s (limits of agreement -0.28 to 1.44 kPa/l/s). CONCLUSION: The poor agreement between Rint and Raw results suggests that Rint measurements cannot substitute for plethysmographic measurements in sedated prematurely born infants.

Airway Obstruction↗
PubMed2005

Changes in the emergency workload of the London Ambulance Service between 1989 and 1999.

OBJECTIVES: To examine changes in the emergency workload of the London Ambulance Service (LAS) between 1989 and 1999. METHODS: All emergency responses by the LAS during week 16 in each of 1989, 1996, and 1999 were studied. For each week, 999 call responses were analysed by time and day of call, and age/sex of the patient. Call response rates were calculated using age/sex census population estimates for London. Changes in call rates over time were calculated as rate ratios. RESULTS: Emergency responses increased from 6624 to 13 178 in the index weeks of 1989-1999. The ratio of response rates (1999/1989) was 1.91 (95% CI: 1.85 to 1.96). The proportion of out of hours calls increased significantly, from 68.8% in 1989 to 71.3% in 1999 (p = 0.0003). Response rates rose significantly more steeply for male patients than female patients from 1989 to 1999: rate ratio (95% CI); male patients 2.00 (1.91 to 2.08), female patients 1.69 (1.62 to 1.77), p<0.0001. Response rates varied by age in each of the three years investigated. Rates were consistently highest for patients aged 75 and above, and lowest for those aged 5-14. However, there was no evidence that call rates had increased disproportionately in any particular age group (p = 0.79). CONCLUSIONS: Demand for emergency ambulance services in London has doubled in a decade. This increase is similar for all age groups, with no evidence of a greater rise in demand among older people. Call rates have increased more steeply in men than in women. Demographic changes do not explain the observed increases in demand.

Adolescent↗
PubMed2004

Associations between perinatal interventions and hospital stillbirth rates and neonatal mortality.

BACKGROUND: Previous studies suggest that high risk and low birthweight babies have better outcomes if born in hospitals with level III neonatal intensive care units. Relations between obstetric care, particularly intrapartum interventions and perinatal outcomes, are less well understood, however. OBJECTIVE: To investigate effects of obstetric, paediatric, and demographic factors on rates of hospital stillbirths and neonatal mortality. METHODS: Cross sectional data on all 65 maternity units in all Thames Regions, 1994-1996, covering 540 834 live births and stillbirths. Hospital level analyses investigated associations between staffing rates (consultant/junior paediatricians, consultant/junior obstetricians, midwives), facilities (consultant obstetrician/anaesthetist sessions, delivery beds, special care baby unit, neonatal intensive care unit cots, etc), interventions (vaginal births, caesarean sections, forceps, epidurals, inductions, general anaesthetic), parental data (parity, maternal age, social class, deprivation, multiple births), and birthweight standardised stillbirth rates and neonatal mortality. RESULTS: Unifactorial analyses showed consistent negative associations between measures of obstetric intervention and stillbirth rates. Some measures of staffing, facilities, and parental data also showed significant associations. Scores for interventional, organisational, and parental variables were derived for multifactorial analysis to overcome the statistical problems caused by high intercorrelations between variables. A higher intervention score and higher number of consultant obstetricians per 1000 births were both independently and significantly associated with lower stillbirth rates. Organisational and parental factors were not significant after adjustment. Only Townsend deprivation score was significantly associated with neonatal mortality (positive correlation). CONCLUSIONS: Birthweight adjusted stillbirth rates were significantly lower in units that took a more interventionalist approach and in those with higher levels of consultant obstetric staffing. There were no apparent associations between neonatal death rates and the hospital factors measured here.

Adolescent↗
PubMed2003

Electrical treatment of tibial non-union: a prospective, randomised, double-blind trial.

Electrical stimulation in the treatment of bony non-union has been used in different forms for many years. However, there is still a lot of uncertainty about its efficacy. We, therefore, undertook a prospective, randomised, double-blind trial to try and determine its effect. Over a period of 5 years, 34 consecutive patients with a tibial non-union met our "criteria for inclusion". Each patient had an oblique fibular osteotomy, followed by a unilateral external fixator. They were then randomly allocated one of two machines. Group 1, the active group, received electrical stimulation from an active machine. Group 2, the dummy group, had an identical machine but without any current passing through the active coils. They were then followed up for 6 months and evaluated clinically and radiologically for bony union. Unfortunately, there was by chance, an imbalance in smoking habit between the two groups. The union rate in the subgroup that smoked was 75% (6/8) in the active group as compared to 46% (6/13) in the dummy group. The active group of non-smokers had 100% (10/10) union rate, compared to 67% (2/3) in the dummy group. Overall 24 out of the 34 patients progressed to union. Out of 18, 16 (89%) in the active group showed bony union as compared to 8/16 (50%) in the dummy. There was, thus, a statistically significant positive association between tibial union and electrical stimulation (odds ratio 8, 95% CI: 1.5-41, P=0.02).

Adolescent↗
PubMed2003

Hostile Hartlepool and genteel Guildford: hostility and health in 10 English towns.

Research from the USA suggests that cities with high mortality rates have high levels of hostility. Our aim was to replicate this research in English towns. A telephone questionnaire, based on the Cook-Medley hostility scale, was administered to random samples of adults in 10 English towns: five with high standardized mortality ratios (SMR) and five with low SMRs. The point estimate for the age-sex-weighted mean hostility score of high SMR towns was higher than that of low SMR towns (mean difference 0.2). However, the 95% confidence interval on the estimate included no difference between the two groups (-0.3-0.8). Our study does not confirm beyond doubt the findings of earlier research in the USA.

Adult↗
PubMed2003

Frequent wheeze at follow up of very preterm infants: which factors are predictive?

OBJECTIVE: To determine if chest radiograph appearance at 28 days or 36 weeks postmenstrual age (PMA) can predict recurrent wheeze or cough at follow up in prematurely born infants more effectively than readily available clinical data. DESIGN: Chest radiographs of infants entered into the UKOS trial, who had had a chest radiograph at 28 days and 36 weeks PMA and completed six months of follow up, were assessed for the presence of fibrosis, interstitial shadows, cystic elements, and hyperinflation. At 6 months of corrected age, the occurrence and frequency of wheeze and cough since discharge were determined using a symptom questionnaire. PATIENTS: A total of 185 infants with a median gestational age of 26 (range 23-28) weeks. RESULTS: Thirty seven infants wheezed more than once a week, compared with the rest of the cohort. These infants had significantly higher chest radiograph scores at 28 days (p = 0.020) and 36 weeks PMA (p = 0.005), with significantly higher scores at 28 days for fibrosis (p = 0.017) and at 36 weeks PMA for fibrosis (p = 0.001) and cystic elements (p = 0.0007). They had also been ventilated for longer (p = 0.013). Forty four infants coughed more than once a week; they did not differ significantly from the rest of the cohort. An abnormal chest radiograph score at 36 weeks PMA had the largest area under the receiver operator characteristic curve with regard to prediction of frequent wheeze. CONCLUSION: An abnormal chest radiograph appearance at 36 weeks PMA predicts frequent wheeze at follow up and appears to be a better predictor than readily available clinical data.

Age Factors↗
PubMed2003

Acute effects of winter air pollution on respiratory function in schoolchildren in southern England.

AIM: To investigate the acute health effects of winter outdoor air pollution (nitrogen dioxide (NO(2)), ozone (O(3)), sulphur dioxide (SO(2)), sulphate (SO(4)(2-)),and particles (PM(10))) on schoolchildren in an area of southern England where levels of SO(2) had been reported to be high. METHODS: A total of 179 children, aged 7-13, from three schools (two urban and one rural location), were included. Peak expiratory flow rate (PEFR) and presence or absence of upper respiratory infections were recorded on 63 school days from 1 November 1996 to 14 February 1997. Air pollution and meteorological data were taken from monitors at each school site. The analysis regressed daily PEFR on pollutant level adjusting for confounders and serial correlation and calculated a weighted pooled estimate of effect overall for each pollutant. In addition, large decrements in PEFR were analysed as a binary outcome. Same day, lag 1, lag 2, and a five day average of pollutant levels were used. RESULTS: There were no clear effects of any pollutant on mean PEFR. In addition, we analysed large PEFR decrements (a binary outcome), observing consistent negative associations with NO(2), SO(4)(2-), and PM(10), although few lag/pollutant combinations were significant: odds ratios (95% CI) for five day average effect: NO(2) 24 h average 1.043 (1.000 to 1.089), SO(4)(2-) 1.090 (0.898 to 1.322), PM(10) 1.037 (0.992 to 1.084). The observed effects of PM(10) (only) were stronger in wheezy children (1.114 (1.057 to 1.174)). There were no consistent negative associations between large decrements and ozone or SO(2). CONCLUSIONS: There is no strong evidence for acute effects of winter outdoor air pollution on mean PEFR overall in this area, but there is evidence for negative effects on large PEFR decrements.

Adolescent↗
PubMed2002

Adjusted mortality rates: a tool for creating more meaningful league tables for stillbirth and infant mortality rates.

A number of problems associated with league tables of performance indicators have been discussed in the literature. This paper attempts to address these problems for stillbirth and infant mortality rates in order to produce meaningful and useful information for the government, general public and health professionals. Composite stillbirth and infant mortality rates, low birth-weight and very low birth-weight rates were determined for the 100 English Health Authorities for 1996-1997. Townsend deprivation scores for these districts were also obtained. The mortality rates were adjusted by multiple regression for very low birth-weight and Townsend score separately and together. Confidence intervals were calculated for the dual-adjusted rates. Almost 60% of the variability in mortality rates were explained by Townsend score and very low birth-weight rates together. Adjusted league tables showed how the individual and combined predictors affect the individual mortality rates for each Health Authority. There was considerable overlap in the confidence intervals for the adjusted rates although there were a few Health Authorities whose mortality rates were clearly below most others. We conclude that fairer and more useful information is provided by geographically based league tables which give both crude rates and rates adjusted for single and multiple predictor variables. The inclusion of confidence intervals aids interpretation of annual random variations and knowledge of differences in the effects of the individual predictors enables better resource targeting.

England↗
PubMed2002

Airway resistance estimation by best fit analysis in very premature infants.

Plethysmographic measurement of airway resistance (R(aw)) has been determined by single-point analysis, usually at 50% of maximum inspiratory flow (MIF). Computer-assisted (best fit) analysis, however, allows R(aw) to be calculated by applying a regression line to any portion of the plethysmograph pressure-flow loop. We determined whether the results of best fit analysis using a computer program, sampling at 200 Hz, were influenced by the portion of the inspiratory loop analysed and if best fit or single-point analysis gave more reproducible results. Twenty infants of median gestational age 26 (range 24-28) weeks, were studied at a median age of 12 (12-14) months corrected for prematurity. R(aw) was calculated by best fit analysis between 0 and 33% MIF, 0 and 50% MIF and 0 and 67% MIF and single-point analysis at 50% of MIF. Similar mean R(aw) values were obtained by best fit analysis between 0 and 33% MIF (2.79 kPa/(l/s)) and 0 and 50% MIF (3.01 kPa/(l/s)) and single-point analysis at 50% MIF (2.86 kPa/(l/s)), but best fit analysis between 0 and 67% gave higher results (3.60 kPa/(l/s)), p < 0.0001. Within the linear portion of the inspiratory loop, the mean intrasubject coefficient of variation was lowest for best fit analysis between 0 and 50% MIF. Best fit computerized analysis between 0 and 50% MIF is recommended as the analysis of choice.

Airway Resistance↗
PubMed2001

Detection of mutated K12-ras in histologically negative lymph nodes as an indicator of poor prognosis in stage II colorectal cancer.

Stage II colorectal carcinoma is characterized by negative lymph node pathology as determined by conventional microscopic examination. These patients generally do not receive adjuvant therapy although 20%-30% will die from metastatic disease. To determine whether K-ras mutations at codon 12 could be used as a sensitive indicator of occult lymph node metastasis in stage II colon carcinoma, a retrospective study was performed using restriction endonuclease-mediated selective polymerase chain reaction (REMS-PCR) amplification. Of 106 colonic tumors analyzed, 46 were identified as positive for a K12-ras mutation in the primary tumor. Multiple lymph node samples from 38 of these 46 patients were examined by a sensitive nested PCR protocol for the presence of a K12-ras mutation. Of these 38 patients, 14 had 1 or more positive lymph nodes by PCR (37%) and 24 were negative for the mutation (63%). Of the 14 patients with a K12-ras mutation detected in lymph nodes, 8 died of the disease within 5 years (57%) compared to only 4 of the 24 patients with ras-negative lymph nodes (17%). The difference in time to death from disease, stratified using K12-ras status of lymph nodes, was statistically significant (P = 0.036; log-rank test). These results suggest K-ras mutation status of lymph nodes in patients with stage II colon cancer might identify a subgroup of patients who are more likely to develop recurrent and/or metastatic disease and benefit from adjuvant therapy. Larger studies are indicated to determine whether detection of K-ras mutation positivity in histologically negative lymph nodes portends a poor prognosis and to determine whether more aggressive use of adjuvant therapy is warranted.

Adenocarcinoma↗
PubMed2000

A randomized, controlled, parallel-group clinical trial comparing multilayer bandaging followed by hosiery versus hosiery alone in the treatment of patients with lymphedema of the limb.

BACKGROUND: Multilayered, low stretch bandages (MLB) combined with exercises, skin care, and manual lymphatic drainage therapy are recommended as an intensive phase of treatment for lymphedema patients. The relative efficacy of each of the components of this comprehensive treatment program have not been determined. This study aimed to compare the effect of multilayer bandaging as an initial phase of lymphedema treatment followed by elastic hosiery versus hosiery alone. METHODS: A randomized, controlled, parallel-group trial was undertaken in the setting of the Lymphedema Clinic, The Royal Marsden Hospital, London. Ninety women with unilateral lymphedema (of the upper or lower limbs) were enrolled in the study. The interventions consisted of 18 days of multilayer bandaging followed by elastic hosiery or hosiery alone, each for a total period of 24 weeks. The main outcome measure was the percentage reduction in excess limb volume. RESULTS: The reduction in limb volume by MLB followed by hosiery was approximately double that from hosiery alone and was sustained over the 24-week period. The mean overall percentage reduction at 24 weeks was 31% (n = 32) for MLB versus 15.8% (n = 46) for hosiery alone, for a mean difference of 15. 2% (95% confidence interval, 6.2-24.2) (P = 0.001). CONCLUSIONS: Multilayer bandaging as an initial phase of treatment for lymphedema patients, followed by hosiery, achieves greater and more sustained limb volume reduction than hosiery alone.

Adult↗
PubMed2000

Which is the best deprivation predictor of foetal and infant mortality rates?

This study investigates which, if any, population-based indicator of deprivation best predicts foetal and infant mortality rates in England. For the year 1995, the deprivation levels of 364 English Local Authorities were compared; using the three commonly used indicators, Jarman score, Townsend score and percentage unemployed. The predictive value of these for stillbirth, neonatal and infant mortality rates was then calculated. The three deprivation indicators were highly inter-correlated (r=0.866-0.924). For each mortality rate, the correlation with deprivation did not differ significantly for the three indicators of deprivation. We conclude, when comparing these outcomes in different areas of England, that any of the three deprivation indicators may be used to adjust for deprivation.

England↗
PubMed2000

Doppler ultrasound of the maternal uterine arteries: disappearance of abnormal waveforms and relation to birthweight and pregnancy outcome.

BACKGROUND: To assess whether the gestation at which abnormal uterine artery waveforms disappear is related to birthweight and complications of pregnancy. METHODS: A prospective study of outcome of pregnancy after a uterine artery Doppler screening program set in an inner city teaching hospital. One thousand five hundred and twenty-four consecutive women attending the Obstetric Department for a routine anomaly scan at between 19 and 21 weeks gestation had maternal uterine arteries assessed using color wave Doppler. Those women in whom the flow was deemed abnormal were recalled for a further scan at 24-26 weeks gestation. The main outcome measures were birthweight, gestation at delivery and incidence of pre eclampsia. RESULTS: The women in whom the uterine artery blood flow was normal at 20 weeks had babies with significantly higher mean birthweight than those who normalized between 20 and 24-26 weeks gestation ('late normalizers') after adjustment for confounding factors; gestational age, maternal height, parity, ethnic group and smoking (mean difference=173 g, 95% confidence intervals 42 to 303 g). CONCLUSIONS: The timing of trophoblast invasion, as reflected by abnormal uterine artery waveforms, may have an effect on birthweight.

Adult↗
PubMed1999

Who calls 999 and why? A survey of the emergency workload of the London Ambulance Service.

BACKGROUND: In 1996-97 there were 623,000 emergency (999) calls made to the London Ambulance Service (LAS) and this represents a 30% increase over the previous five years. The reasons for this increase, which is also observed nationally, remain unknown. It has been suggested that some callers may be using the 999 service "inappropriately" but no data are available from the ambulance service. OBJECTIVE: To describe the workload of the emergency ambulance service in London with specific reference to the nature and characteristics of 999 calls, to determine who dials 999 and why, and to establish the number and types of calls that could most appropriately be dealt with by other agencies. DESIGN: A one week census of all emergency calls responded to by the LAS. SETTING: Sixty eight LAS stations. METHODS: Collation of all routine LAS incident forms (LA4) including the classification of the crews' free text description of the incident. This was supplemented by a detailed workload questionnaire for 25% of calls. RESULTS: There were 10,921 calls responded to from 29 April to 5 May 1996. The census showed that the daily number of calls was highest on Saturday and lowest on Wednesday with about half being made during normal general practitioner (GP) working hours. Half of all calls were for women and one third were for people aged > or = 65. Accidents were the commonest type of incident (24%). The remainder comprised various medical conditions such as respiratory, cardiac, and obstetric problems. In 1.5% of calls there was no illness, injury, or assistance required and 5% were for "general assistance" and mostly concerned people aged > or = 65. The workload survey indicated that two thirds of incidents occurred at home and 70% of callers had not tried to contact a GP before dialing 999. In the professional opinion of the responding crew, 60% of calls required a 999 response, with the remainder thought more appropriately dealt with by other services such as primary care, psychiatric services, and social services. CONCLUSIONS: This study suggests that while the majority of 999 calls were "appropriate", part of the 999 workload could be dealt with by other services. More research is required to clarify why people contact the 999 service for non-emergency incidents and also to establish the views of GPs and other agencies as to the role and function of the IAS.

Emergency Medical Service Communication Systems↗