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Biomedical subjects

J P Wyllie

Publications and source records attributed to J P Wyllie.

12 recordsLinked to original sources
PubMed1999

Neonatal resuscitation--a practical assessment.

Current European neonatal resuscitation guidelines (Zideman et al. Resuscitation 1998;37:103-110) advocate cardiopulmonary resuscitation (CPR) at 120 compressions per minute in a ratio of 3:1. This is commonly interpreted as a net rate, thus requiring delivery of 40 breaths per minute, which is the upper end of the range of 30-40 breaths per minute suggested in the guidelines. At least one other interpretation is available, but the correct one is not specified. No studies have evaluated whether the rates inferred by the guidelines can be achieved. This study assesses the ability of trained hospital providers to fulfil these criteria in a simulated arrest scenario. A group of anaesthetists, paediatricians, midwives and neonatal nurses was asked to perform CPR either as single rescuers or in pairs, for 5 min, following European Resuscitation Council guidelines. Breaths and compressions delivered were measured by inductance plethysmography. The number of breaths delivered in the first and fifth minute of the scenario were measured, as well as the quality of delivered breaths. Of 33 single resuscitators, none were able to deliver 40 breaths per minute in either the first minute (range 11-34; median 20; interquartile range 14-26) or the fifth (13-35; 19; 15.25-26.5). Of 18 pairs of rescuers, four achieved 40 breaths per minute in the first minute (24-45; 33.5; 29.75-38.25) but only three of 17 were able to sustain this to the fifth minute (21-48; 35; 30.5 39). One pair did not complete 5 min of resuscitation. Single rescuers were unable to achieve the rate of CPR suggested by current guidelines. Only 22% of paired rescuers were able to achieve this standard in the first minute, falling to less than 20% by the fifth minute. We recommend modifying the guidelines to make them unambiguous and practicable, with the emphasis shifted onto the quality of compressions and ventilations, rather than quantity.

Cardiopulmonary Resuscitation↗
PubMed1999

Paediatric basic life support: a practical assessment.

Current European Resuscitation Council (ERC) guidelines for paediatric basic life support advocate delivery of 20 cycles/min at a compression rate of 100/min and a compression:ventilation ratio of 5:1 (Resuscitation 1997;34:115-27; Resuscitation 1998;37(2):97-100). We have evaluated whether cardiopulmonary resuscitation (CPR) can be delivered at this rate by hospital providers. We recruited 24 rescuers, all of whom had successfully completed a training course in paediatric life support. Each was asked to perform single rescuer CPR on a Resusci-Junior mannequin (Laerdal, Kent, UK) for 5 min, following the current ERC guidelines. Compressions and ventilations were recorded in real time by inductance plethysmography. Maintenance of the 5:1 ratio was ensured by investigator observation. Cycles of CPR in the first and fifth minutes of resuscitation were counted. The average duration of compression, ventilation and 'transfer time' spent between these two activities was calculated as a percentage of the average duration of a cycle of CPR. All 24 rescuers completed 5 min of resuscitation. Twenty-three of 24 were unable to deliver 20 cycles of CPR in either the first minute (range 8-27; median 11; interquartile range (IQR) 10-13.75) or in the fifth minute (8-26; 11.5; 10-13.75). The median (IQR) duration of a cycle of CPR was 5 s in the first and fifth minutes. Transfer time comprised 30% of total cycle time. In this study, over 95% of single rescuers trained in paediatric life support were unable to deliver 20 cycles of CPR/min. The guidelines make no allowance for time spent moving between compression and ventilation activity. Future consensus statements should take account of this transfer time. Any changes in recommendations should obviously be prospectively audited with Utstein-style reporting and studies of practicability.

Cardiopulmonary Resuscitation↗
PubMed1999

The natural history of ventricular septal defects.

AIMS: To correlate the size and position of isolated ventricular septal defects with closure rate in a cohort of children with mean follow up of more than six years. DESIGN: A birth cohort was identified using the northern region cardiac database. The following were noted from case notes: defect size, position, means of closure, and age at closure. RESULTS: 68 children were identified. 49 defects were small, 14 were moderate, and 5 were large. 13 cases required surgical closure, including 12 perimembranous defects. 35 defects closed spontaneously. Nine of the small muscular defects remained open and five of the small perimembranous defects remained open. The spontaneous closure rate for muscular defects was significantly greater than for perimembranous defects. Mean age of follow up for patients who still have defects is 76 months. CONCLUSIONS: The position of a ventricular septal defect is extremely relevant to its natural history. Perimembranous defects accounted for most of the moderate and large defects that required surgical intervention. After more than six years almost a third of all perimembranous and just over two thirds of all muscular defects closed spontaneously.

Child, Preschool↗
PubMed1999

Prevalence and clinical significance of cardiac murmurs in neonates.

AIM: To determine the prevalence and clinical significance of murmurs detected during routine neonatal examination. METHODS: In a two year prospective study, 7204 newborn babies underwent routine examination by senior house officers. All those with murmurs underwent echocardiographic examination. All babies presenting later in infancy were also identified, to ascertain the total prevalence of congenital heart disease in infancy. RESULTS: Murmurs were detected in 46 babies (0.6%) of whom 25 had a cardiac malformation. The most common diagnosis was a ventricular septal defect, although four babies had asymptomatic left heart outflow obstruction. A further 32 infants from the same birth cohort had a normal neonatal examination but were found to have a cardiac malformation before 12 months of age. CONCLUSIONS: The neonatal examination detects only 44% of cardiac malformations which present in infancy. If a murmur is heard there is a 54% chance of there being an underlying cardiac malformation. Parents and professionals should be aware that a normal neonatal examination does not preclude a clinically significant cardiac malformation. The detection of a murmur should prompt early referral to a paediatric cardiologist for diagnosis or appropriate reassurance.

Echocardiography↗
PubMed1997

Strategies for antenatal detection of Down's syndrome.

AIM: To predict the effect of maternal serum screening and fetal echocardiography on the birth prevalence of Down's syndrome. METHODS: The outcome of all Down's syndrome pregnancies in the Northern Health Region between 1985 and 1991 was retrospectively ascertained. The number and outcome of all Down's syndrome pregnancies were used to define a theoretical population which would exist in the absence of screening. Published reports were used to predict the effects of screening strategies. RESULTS: Down's syndrome was identified in 412 pregnancies of which 315 (76%) resulted in live birth. A theoretical population with no antenatal screening would be expected to produce 31 stillbirths and 381 (92%) live births affected by Down's syndrome. In the same population a programme of maternal serum screening and fetal echocardiography would lead to 155 and 14 terminations, respectively, and when combined, would reduce affected live births to 229 (56%). CONCLUSIONS: Even if maternal serum screening and fetal echocardiography achieve their predicted potential, around half of all pregnancies affected by Down's syndrome will result in live born babies.

Adult↗
PubMed1996

Natural history of trisomy 18.

It has been suggested that survival in babies with trisomy 18 may be better than previously recognised, and that cardiac surgery may be justified. A population based study spanning seven years in one English health region is presented. The fetal prevalence at 18 weeks was 1 in 4274 and birth prevalence 1 in 8333 live births. Trisomy 18 was detected antenatally in 43% of cases, but almost 90% of those born without a diagnosis were known to be growth retarded in utero. More than 50% of liveborn infants were delivered by caesarean section. The median survival of those born alive was 3 days with no babies living longer than one year. Cardiac malformations were not universal but were present in more than 87% of those for whom there were data. However, in only three cases were cardiac problems implicated in the death of the infants. Cardiac surgery is not likely to improve the survival of infants with trisomy 18 and at present cannot be justified. The most common mode of death was central apnoea.

Adult↗
PubMed1994

Natural history of trisomy 13.

The poor prognosis of patients with trisomy 13 has long been accepted and has been ascribed to brain and heart malformations. It has been suggested, however, that the long term survival is better than was previously thought and that cardiac surgery may be justified. This population based study reviews the incidence, antenatal diagnosis, spectrum of survival from congenital heart disease, and mode of death for patients with trisomy 13 in the Northern Health Region from 1985 to 1992. There was an observed prevalence at birth of 0.049/1000 live births and an expected prevalence, allowing for antenatal diagnosis, of 0.077. None of the cardiac lesions found would cause early death. The median survival in this series was four days; the longest survival was 3.5 months. The principal mode of death was apnoea in 14 of 16 children, irrespective of the presence of a cranial abnormality. In the light of these findings, cardiac surgery cannot be justified in patients with trisomy 13.

Adult↗
PubMed1987

Marrow repopulation in mice treated with busulphan or isopropyl methane sulphonate and bone marrow.

By using karyotypic analysis of female mice treated with busulphan or isopropyl methane sulphonate (IMS), and injected with male bone marrow the donor contribution to both total marrow cellularity and spleen colony forming cells (CFU-S) was assessed for up to 6 months after transplant. In the mice treated with busulphan the marrow cells yielded metaphases of which between 40% and 83% were of donor type. Between 60% and 97% of metaphases in spleen colonies formed in irradiated mice were of donor type during the 24-week study period. In contrast, mice prepared for the transplant with IMS showed no cells of donor type at any time after transplant, neither did they possess CFU-S of donor type. We were therefore led to conclude that the donor cells made no contribution to longterm engraftment in mice prepared with IMS, whilst in those prepared with busulphan they were the predominantly active haemopoietic cells. These results are consistent with a model of haemopoiesis in which the most primitive cells reside in a 'niche' where they are resistant to the effects of IMS but susceptible to the action of busulphan. Busulphan may vacate some niches to allow engraftment by transplanted marrow, whilst IMS yields no unoccupied niches for grafted cells to occupy, and cannot therefore lead to a stable chimaerism.

Alkylating Agents↗