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Biomedical subjects

A B Gill

Publications and source records attributed to A B Gill.

16 recordsLinked to original sources

Consent for neonatal research.

Inherent to all medical research is respect for the rights of the individual. Neonatal research is made more complex by the issue of proxy consent. Obtaining valid informed consent for entry of an infant into a research project needs to deal with this complexity. New evidence on the role and responsibilities of parents in giving consent has implications for all clinical staff that are considering embarking on and/or recruiting infants in research projects. This review explores the issues around informed consent for neonatal research and provides a framework by which consent could be improved. It is to be hoped that such improvements to the process will increase recruitment of infants to research studies while enhancing the validity of the consent process.

Attitude to Health↗

Effectiveness of topical chlorhexidine powder as an alternative to hexachlorophane for the control of Staphylococcus aureus in neonates.

We routinely phage-type Staphylococcus aureus isolates from high-risk inpatients each week. This surveillance approach previously identified a five-year outbreak of a methicillin-susceptible S. aureus strain (MSSA, PT 53,85), which affected 202 babies on a regional neonatal unit. We previously reported this outbreak and the multiple staged infection control measures that were required to end it. These included strict emphasis on hand hygiene, environmental and staff surveillance sampling, application of topical triclosan solution and hexachlorophane powder, aseptic handling of a skin protectant material, and use of topical mupirocin for staff nasal carriers of the endemic MSSA strain and for babies colonized or infected with S. aureus. In summer 2000 topical hexachlorophane powder became unavailable and we therefore substituted topical 1% chlorhexidine powder as part of routine umbilical decontamination. We have continued prospective S. aureus surveillance for the past five years to monitor the effect of this practice change. We observed a continued decline in the numbers of monthly MSSA isolates from neonatal unit babies. Since the substitution of chlorhexidine for hexachlorophane, the median monthly number of MRSA isolates has been 0.5 (range 0-4). Only sporadic S. aureus PT 53,85 isolates were recovered. Control of S. aureus in our regional neonatal unit, in particular an endemic MSSA strain, was maintained when topical umbilical hexachlorophane powder was substituted with 1% chlorhexidine powder.

Administration, Topical↗

Perinatal transport: problems in neonatal intensive care capacity.

OBJECTIVE: To assess the quantity and nature of transfers within the Yorkshire perinatal service, with the aim of identifying suitable outcome measures for the assessment of future service improvements. DESIGN/SETTING: Collection of data on perinatal transfers from all neonatal and maternity units located in the Yorkshire region of the United Kingdom from May to November 2000. PATIENTS: Expectant mothers (in utero transfers) and neonates (ex utero transfers). INTERVENTIONS: None MAIN OUTCOME MEASURES: Quantification of in utero and ex utero transfers; the reasons for and resources required to support transfers; the nature of each transfer (acute, specialist, non-acute, into or out of region). RESULTS: In the period studied, there were 800 transfers (337 in utero; 463 ex utero); 306 transfers were "acute" (80% of transfers in utero), 214 because of specialist need, and 280 "non-acute". Some 37% of capacity transfers occurred from the two level 3 units in the region. Of 254 transfers out of the 14 neonatal units for intensive care, 44 (17.3%) were transferred to hospitals outside the normal neonatal commissioning boundaries. CONCLUSIONS: The study highlights a continuing apparent lack of capacity within the neonatal service in the Yorkshire region, resulting in considerable numbers of neonatal and maternal transfers.

England↗

Is it in a neonate's best interest to enter a randomised controlled trial?

Clinicians are required to act in the best interest of neonates. However, it is not obvious that entry into a randomised controlled trial (RCT) is in a neonate's best interest because such trials often involve additional onerous procedures (such as intramuscular injections) in return for which the neonate receives unproven treatment or a placebo. On the other hand, neonatology needs to develop its evidence base, and RCTs are central to this task. The solution posited here is based on two points. First, "best interest" is not equivalent to "the best possible interest" only to "best interest within a certain realm". The realm of deliberation when asking the title question is the neonate's health. Deliberating in this realm may involve the exclusion from consideration of some factors that might be thought relevant (such as parental wealth). Furthermore, circumstances may dictate the need to deliberate on other factors that might be thought irrelevant (such as health care resources). Second, deciding on a neonate's best interest does not involve "putting oneself in its shoes". Rather, it involves asking in what it has an interest, or stake. These will include some things in which we all, as human beings, have a stake, such as medical progress. Putting these two points together, in the realm of health the answer to whether RCT entry is in a neonate's best interest is usually very finely balanced. Where this is the case, it is reasonable to invoke a broader notion of best interest and include a broader range of elements in which the neonate has a stake, including medical progress. In this way RCT entry can, usually, be said to be in a neonate's best interest.

Child Advocacy↗

A five year outbreak of methicillin-susceptible Staphylococcus aureus phage type 53,85 in a regional neonatal unit.

We identified a 5-year outbreak of a methicillin-susceptible Staphylococcus aureus (MSSA) strain, affecting 202 babies on a neonatal unit, by routine weekly phage typing all S. aureus isolates. Multiple staged control measures including strict emphasis on hand hygiene, environmental and staff surveillance sampling, and application of topical hexachlorophane powder failed to end the outbreak. S. aureus PT 53,85 (SA5385) was found on opened packs of Stomahesive, used as a neonatal skin protectant. Only following the implementation of aseptic handling of Stomahesive, and the use of topical mupirocin for staff nasal carriers of SA5385, and for babies colonized or infected with S. aureus, did the isolation rate of SA5385 decline. DNA fingerprinting indicated that > or =, 95% of SA5385 isolates were clonal. In vitro death rates of SA5385 on Stomahesive with human serum were significantly lower than on Stomahesive alone (P = 0.04), and on cotton sheet with serum (P = 0.04), highlighting the potential of this material as a survival niche. Phage typing remains a valuable, inexpensive and simple method for monitoring nosocomial MSSA infection.

Bacteriophage Typing↗

Cardiac effects of short course dexamethasone in preterm infants.

AIM: To examine the incidence and natural history of left ventricular hypertrophy (LVH) associated with the shorter 2-3 week course of dexamethasone, now more usual, for chronic lung disease. METHOD: Thirty one infants, gestational age 23-34 (median 26) weeks, birthweight 500-2054 (median 815)g, received dexamethasone, starting at 0.4-0.6 mg/kg/day, at a median of 11 days of age (range 2-34), weaning over a period of 2-3 weeks. Eighteen preterm neonates were studied as controls over a similar time period. Serial echocardiographic measurements of end diastolic interventricular septum (IVSd) and left ventricular posterior wall (LVPWd) thicknesses were taken before, and up to 48 days after, starting dexamethasone. Maximum Doppler blood flow velocities from the left ventricular outflow tract (LVOT) were measured. RESULTS: Left ventricular hypertrophy (LVH) occurred in 29 babies (94%). Median hypertrophy of the IVSd in those receiving dexamethasone was 67% and LVPWd 56% of baseline measurements, significantly greater than control infants (p < 0.001). LVH appeared by a median of three days, peaking by a median of 10 days. All resolved by a median of 27 days. LVOT obstruction was not seen. There was no significant correlation with birthweight, gestation, blood pressure, or glucose tolerance. CONCLUSIONS: LVH developed in almost all preterm neonates receiving a 2-3 week course of dexamethasone, but was of little clinical importance and always resolved. Echocardiography is probably not required routinely in infants receiving such short course dexamethasone for chronic lung disease.

Anti-Inflammatory Agents↗

Reference ranges for cardiac dimensions and blood flow velocity in preterm infants.

AIM: To establish reference ranges for cardiac dimensions and Doppler measurements in preterm infants. METHODS: 79 infants of less than 34 weeks' gestation were examined by echocardiography on days 0, 7, and 28 after birth, to produce a set of reference ranges and to examine changes in these indices over the first month of life. The following dimensions were measured: interventricular septum, left ventricular posterior wall, left interventricular diameter at end systole and diastole, left atrium, and aortic root; Doppler measurements were made of maximum blood flow velocity (Vmax) through the pulmonary, aortic, mitral, and tricuspid valves. RESULTS: Reference ranges are given. Cardiac dimensions correlated well with gestation and birth weight but Vmax did not. There was a significant increase in measurements over time. The "normal" preterm infant also appeared to often have asymmetrical septal hypertrophy. Antenatal dexamethasone administration did not appear to affect the measurements. CONCLUSIONS: There is a close correlation with both gestation and birth weight for all physical measurements. Echocardiograms in preterm babies clearly differ from those in older children and adults.

Blood Flow Velocity↗

Raised pulmonary artery pressure in very low birthweight infants requiring supplemental oxygen at 36 weeks after conception.

This study aimed to investigate the changes in pulmonary artery pressure in infants with chronic lung disease who then developed prolonged oxygen dependency. The time to peak velocity: right ventricular ejection time (TPV:RVET) ratio calculated from the Doppler waveform, which correlates negatively with pulmonary artery pressure, was used. Thirty four infants with chronic lung disease were studied. At 36 weeks after conception 19 infants still required supplemental oxygen (POD group) and 16 infants were in air (controls). Over the first three weeks, there was a significant rise in the ratio in both groups, indicating a fall in pulmonary arterial pressure. From the third week onwards the ratio was significantly lower in the POD group. There was a significant rise in the ratio from four to 36 weeks after conception in the control group; the POD group showed a tendency towards a fall over the same time period. The requirement for supplemental oxygen almost mirrored the changes in the ratio in both groups but was not significantly different until the fifth week after birth. These data suggest that pulmonary arterial pressure has a significant role in the pathophysiology of prolonged oxygen dependency and may be important in the subsequent morbidity associated with this group of very low birthweight infants.

Blood Pressure↗

Echocardiographic assessment of cardiac function in shocked very low birthweight infants.

The contribution of abnormal cardiac function to hypotension and metabolic acidosis, which affect approximately 40% of ventilated very low birthweight infants in the first 24 hours after birth was assessed using M mode, two dimensional, and Doppler echocardiography in 75 very low birthweight infants during the first few hours after birth. Thirty four infants whose blood pressure was less than the 10th centile or who had a metabolic acidosis in the first 24 hours were compared with 41 who showed neither feature. The median shortening fraction was significantly lower in the hypotensive/acidotic (shocked) group than in the controls. In 16 of 34 (47%) shocked infants left ventricular contractility and output were significantly worse than in the control subjects. One and five minute Apgar scores were also significantly lower in the shock group when compared with controls. Cardiac dysfunction was an important feature in the shocked very low birthweight infants. It is speculated that volume expansion may not always be the most appropriate first line treatment for such infants.

Acidosis↗

Pulmonary artery pressure changes in the very low birthweight infant developing chronic lung disease.

Pulmonary artery pressure may be estimated non-invasively in the premature newborn infant because of its negative correlation with the time to peak velocity:right ventricular ejection time (TPV:RVET) ratio calculated from the pulmonary artery Doppler waveform. We studied 54 very low birthweight infants on days 1, 2, 3, 7, 14, 21, and 28 after birth. Thirty four infants developed chronic lung disease (CLD). Twenty did not and acted as controls. After correcting the TPV:RVET ratio for heart rate (TPV:RVET(c)), during the first 14 days the TPV:RVET(c) ratio rose progressively in both groups suggesting a fall in pulmonary artery pressure. This occurred at a significantly slower rate in the CLD group. From days 14 to 28 there was a significant fall in the ratio in the CLD group only, suggesting an increase in pulmonary artery pressure. Using CLD as the end point, a TPV:RVET(c) ratio < 0.54 on day 7 had a predictive value of 78% (sensitivity 73%, specificity 65%). This rose to a predictive value of 97% (sensitivity 88%, specificity 95%) on day 28. The non-invasive assessment of pulmonary artery pressure may be useful in the early clinical management of the very low birthweight infant at risk of developing CLD.

Blood Flow Velocity↗

Randomised controlled trial of plasma protein fraction versus dopamine in hypotensive very low birthweight infants.

Around 20% of very low birthweight infants admitted to a neonatal intensive care unit become hypotensive within 24 hours of their admission. Standard treatment is either expansion of the circulating volume by the infusion of plasma protein fraction or by using dopamine to improve cardiac function. The purpose of this study was to investigate by a randomised controlled trial which was the most appropriate treatment. Thirty nine infants were randomised to receive either plasma protein fraction or dopamine as first line treatment if they became hypotensive within 24 hours of admission to the neonatal intensive care unit. Seventeen of 19 (89%) infants responded to dopamine, whereas only 9/20 (45%) responded to plasma protein fraction. The median dose of dopamine needed to increase the blood pressure to at least the 10th centile was 7.5 micrograms/kg/min and was infused for a median duration of 18 hours. These observations suggest that dopamine should be used earlier in the treatment of these infants than has previously been recommended.

Blood Proteins↗

Randomised trial of routine versus selective paralysis during ventilation for neonatal respiratory distress syndrome.

The strategy of non-selective neuromuscular paralysis was compared with that of synchronised (fast rate) ventilation and selective paralysis in infants receiving mechanical ventilation for respiratory distress syndrome with chronic lung disease as the primary outcome measure. One hundred and ninety three infants weighing under 2000 g were randomly allocated to receive either pancuronium during mechanical ventilation in the acute phase of respiratory distress syndrome (non-selective group) or synchronised ventilation (initial ventilatory rate at or above that of the infant's) (selective group). Infants in the selective group received pancuronium if they were consistently expiring during the inspiratory phase of the ventilator cycle. There was no significant difference between the groups with respect to birth weight, gestation, and sex distribution. There was no significant difference between the group with respect to death (selective 19%, non-selective 16%), pneumothorax (selective 14%, non-selective 14%), chronic lung disease (selective 49%), non-selective 47%), and oxygen dependency at 36 weeks' postmenstrual age (selective 32%, non-selective 39%). Routine paralysis of ventilated infants has potential complications that may be avoided by using synchronised ventilation. As the latter is not associated with an increased incidence of long term respiratory complications, it is concluded that it is the optimum strategy of the two for ventilating infants with respiratory distress syndrome.

Chronic Disease↗

Effects of transfusion in anemia of prematurity.

The authors aimed to test the hypothesis that blood transfusions depress hematopoiesis in healthy infants with anemia of prematurity (AOP). They also set out to find markers that predict recovery from AOP. Thirty-nine premature babies underwent weekly and post-transfusion measurements of hemoglobin concentrations, reticulocyte counts (RCC), and erythropoietin levels (EPO). RCC and EPO dropped significantly 7 days after a blood transfusion but had normalized after 14 days. Elevated RCC or EPO levels were not predictive of an increase in hemoglobin. Postnatal HbFg/dL was higher in babies who had received transfusions. The authors conclude that blood transfusions depress erythropoiesis in infants with AOP and stimulate HbF synthesis but this effect is not sustained. Reticulocyte counts and erythropoietin levels are unhelpful in predicting recovery from AOP.

Anemia, Neonatal↗