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Biomedical subjects

H Gamsu

Publications and source records attributed to H Gamsu.

At least 19 recordsLinked to original sources

Cerebral and renal artery blood flow velocity before and after birth.

OBJECTIVE: To document perinatal changes in cerebral and renal artery haemodynamics in premature growth-retarded and normal term infants. DESIGN: Longitudinal study of individual infants. Doppler ultrasound measurements of blood flow velocity (BFV) in the middle cerebral and renal arteries were obtained before delivery, soon after delivery and during the first week of postnatal life. SETTING: Teaching hospital obstetric and neonatal units. SUBJECTS: 13 severely growth retarded infants born at 28-36 weeks gestation, and eight normally grown infants born at term. RESULTS: In both groups, BFV in the cerebral artery was significantly lower in the first few hours after birth than in fetal life, but subsequently increased to reach pre-delivery values by the end of the first week. In contrast, BFV in the renal artery during the first postnatal day was not significantly different from fetal values, but it also increased during the subsequent week. In six of the preterm growth-retarded infants, fetal blood gases were measured in samples obtained by cordocentesis, and in these cases an increase in blood oxygen content at birth was documented. CONCLUSIONS: Cerebral artery BFV falls at birth and is relatively low during the time that premature infants are at the greatest risk of developing periventricular haemorrhage.

Blood Flow Velocity↗

The association between small size for gestational age and perinatal and neonatal death in a UK Regional Health Authority.

Confidential enquiry into stillbirth and death in infancy is a health service requirement in England, Wales and Northern Ireland. A confidential review of perinatal death has been conducted in South-East Thames Region since 1988. Data collected for this review are analysed here. Among the 1662 singleton deaths in the enquiry from 1988 to 1991, 530 (32%) babies were small for gestational age (SGA < 10th centile): 338 of these (64%) were < 3rd centile and the remainder were between 3rd-10th centile. Small size for gestational age was significantly associated with a previous SGA baby (P = 0.02), proteinuric hypertension (P = 0.001) and increased placental-birthweight ratio (P = 0.008). Only 135 (25%) SGA fetuses were identified antenatally and multiple logistic regression showed that antenatal detection was independently related to proteinuric hypertension [odds ratio (OR) = 2.47, 95% confidence interval (CI) 1.47-4.17, P = 0.001) and to being < 3rd centile rather than 3rd-10th centile (OR = 3.16, 95% CI 1.96-5.10, P = 0.001). Although confidential enquiries have been criticised for a lack of objectivity the study indicates how data from such an enquiry can increase knowledge of events influencing peri- and neonatal outcome allowing strategies to be devised to effect change.

Data Collection↗

Preterm prelabour amniorrhexis: intrauterine infection and interval between membrane rupture and delivery.

This study aimed to determine if fetal bacteraemia and amniotic fluid infection at the time of membrane rupture reduces the interval between membrane rupture and the onset of labour in pregnancies complicated by preterm prelabour amniorrhexis. Sixty nine pregnancies with preterm prelabour amniorrhexis at 12-36 weeks' gestation that were managed expectantly had spontaneous onset of labour. In all cases cordocentesis and amniocentesis were performed and fetal blood and amniotic fluid were cultured for aerobic and anaerobic bacteria. In the group with negative fetal blood and amniotic fluid cultures (group 1) the median interval from amniorrhexis to delivery was 41 days (range 1-161) and there was an inverse correlation between gestational age at amniorrhexis and delivery interval. In the group with negative fetal blood but positive amniotic fluid cultures (group 2) the median amniorrhexis to delivery interval was nine days (range 1-37), and in the group with positive fetal blood cultures (group 3) the interval was two days (range 1-5). These findings suggest that pregnancies complicated by preterm prelabour amniorrhexis and fetal bacteraemia undergo spontaneous labour within five days of membrane rupture, and if labour does not occur then infection is unlikely.

Amniotic Fluid↗

Vitamin A levels and feeding practice in neonates with and without chronic lung disease.

Infants with chronic lung disease (CLD) have been demonstrated to have low vitamin A levels. The aim of this study was to assess factors which influenced this association. Vitamin A levels of infants born at less than 32 weeks gestational age with and without CLD were determined and related to feeding practice. The infants with CLD had statistically significantly lower vitamin A levels on days 21 to 30 and days 31 to 40. From day 11 onwards, the median Vitamin A levels were less than 60% of the minimum acceptable level for a healthy child or adult. Infants with CLD required significantly longer mechanical ventilation and parenteral nutrition than controls and there was a significant positive correlation between duration of mechanical ventilation and parenteral nutrition (r = 0.83). Infants with CLD received significantly less vitamin A supplementation than the infants without CLD. Our results thus suggest that feeding practice explains the association of CLD and vitamin A deficiency in preterm infants.

Chronic Disease↗

Endoscopic examination of the neonatal larynx at extubation: a prospective study of variables associated with laryngeal damage.

Despite postmortem and clinical studies, the etiological factors that determine why only a proportion of intubated neonates develop subglottic stenosis remain unclear. This prospective study was initiated to identify factors that were associated with laryngeal abnormalities secondary to intubation. Thirty neonates were examined at extubation by two independent observers blinded to the neonate's ventilatory history. Thirty-six possible prognostic indicators were recorded for each neonate. After screening by univariate (chi 2) analysis, 10 indicators were selected for further analysis. Of these 10 selected only two indicators showed an association with the laryngeal appearance. Active neonates had significantly more abnormalities in the supraglottis (P = 0.004) than those who were quiescent. Younger neonates had more abnormalities in the glottis though the significance level was marginal (P = 0.056). Other prognostic indicators, including birthweight, gestational age, duration of intubation and frequency of intubation, were not significantly related to laryngeal appearance. This study supports the hypothesis that the etiology of laryngotracheal stenosis is multifactorial, and has identified two possible etiological factors: age and neonatal activity. Neonatal activity has not been identified previously as an etiological factor. The contribution of individual factors may vary from one neonatal unit to another, as a result of variation in intubation, ventilation and extubation policy. This could explain the inconsistency in etiological factors identified by previous studies. It is therefore not yet possible to recommend a standard technique for the ventilation of premature neonates that would further reduce the incidence of laryngotracheal stenosis.

Erythema↗

Gas trapping during high frequency positive pressure ventilation using conventional ventilators.

Inspiratory and expiratory volumes were measured in 51 preterm infants with respiratory distress syndrome (RDS), when comparing two ventilator rates, 60 and 120 breaths/min. Gas trapping was not demonstrated at rates of 60, but in 11 infants at 120 breaths/min and this was more common in the paralysed infants and those more mature than 31 weeks gestational age (P less than 0.05). The median change in functional residual capacity resulting from gas trapping was 3.8 ml/kg. We conclude rates of 120 breaths/min can be used in the majority of non-paralysed infants without gas trapping but should be avoided in paralysed infants more mature than 31 weeks.

High-Frequency Ventilation↗

Listeriosis revisited: the role of the obstetrician.

The clinical course and outcome is described of three pregnancies complicated by listeriosis encountered during a 6-month period. All three ended in preterm labour characterized by the passage of meconium by the fetus. Two babies died in the early neonatal period and the third survived with neurological handicap. Although the diagnosis of listeriosis was made only after delivery, all the mothers had a pyrexial illness before delivery. A high index of suspicion is needed for the early detection and prompt treatment of this life-threatening perinatal infection. Effective advice concerning prevention of listeriosis by avoidance of high-risk foods must be given to women during pregnancy.

Adult↗

Randomised controlled trial of two methods of weaning from high frequency positive pressure ventilation.

Forty preterm infants suffering from respiratory distress syndrome were entered into a randomised controlled trial to assess the importance of the length of inspiratory time during weaning from high frequency positive pressure ventilation (HFPPV). Two weaning regimes were compared: in one (group A) inspiratory time was limited to 0.5 seconds throughout weaning, in the other (group B) ventilator rate was reduced by increasing both inspiratory and expiratory time (inspiration:expiration ratio constant) until inspiratory time reached 1.0 seconds. At ventilator rates of 20 and 40 breaths/minute an acute comparison was made in all 40 infants of the two inspiratory times; despite the lower mean airway pressure associated with the shorter inspiratory time blood gases were maintained. There was no difference in the incidence of pneumothoraces or need for reventilation between the two regimens but infants in group A had a shorter duration of weaning. We conclude limitation of inspiratory time to 0.5 seconds during weaning from HFPPV is advantageous to preterm infants with respiratory distress syndrome.

Carbon Dioxide↗

Five-year follow-up study of extremely low-birthweight infants.

This study investigated whether extremely low-birthweight (ELBW) babies, who at two years had no major handicaps, were at higher risk for intellectual and socio-emotional problems at five years than a control group of children with normal birthweights. There were statistically significant differences between the two groups. The ELBW children were language-delayed, and more active and more intense in their behaviour. There was a tendency for the ELBW children to be lighter and shorter than the controls, but their mean head-circumference was significantly smaller. In general, however, if no serious neurological, neurosensory or cognitive impairment is found among ELBW children at two years, later cognitive and socio-emotional development is likely to be within the normal range.

Child↗

Mortality, morbidity, growth and development of babies weighing 501-1,000 grams and 1,001-1,500 grams at birth.

During the five-year period, January 1980 to December 1984, 149 babies of extremely low birthweight (ELBW; 501-1,000 g) and 296 of very low birthweight (VLBW; 1,001-1,500 g) were admitted to King's College Hospital, Neonatal Intensive Care Unit. The survival rates were 51.7% and 82.8% respectively. There were more peri- and postnatal problems in the ELBW babies than the VLBW babies and these differences were highly significant. All surviving babies born between January 1980 and December 1982 were followed up until aged two. The ELBW children had a higher incidence of neuro-developmental sequelae than those of VLBW especially when both major and minor problems were considered. Their developmental quotients were lower at one and two years. Significantly more ELBW children were of short stature and low weight (less than 3rd centile). By two years of age the differences between ELBW and VLBW children in stature and mean DQ had lessened.

Child Development↗

Doppler studies in the growth retarded fetus and prediction of neonatal necrotising enterocolitis, haemorrhage, and neonatal morbidity.

In 82 consecutive cases of intrauterine growth retardation managed by established criteria fetal Doppler studies identified 29 fetuses with absence of end diastolic frequencies in the fetal aorta. These same fetuses were significantly more growth retarded (p less than 0.001) and had an earlier gestational age at delivery (p less than 0.001) than those with end diastolic frequencies present. A subgroup of these cases was analysed in more detail to examine the prognostic value of this phenomenon for the neonate. Two groups of neonates of equivalent gestational age and with a birth weight below 2000 g were compared. There were 26 neonates with absent end diastolic frequencies (group 1) and 20 with end diastolic frequencies (group 2) in the fetal aorta. Those in group 1 were more likely to suffer perinatal death (p less than 0.05), necrotising enterocolitis (p less than 0.01), and haemorrhage (p less than 0.05). Only 4 (15%) of the babies in group 1 had an uncomplicated neonatal period compared with 15 (75%) in group 2 (p less than 0.001). The circulatory changes identified in these cases may provide a more sensitive measure of critical fetal compromise than current techniques and thus allow the clinician to deliver the fetus before irreversible tissue damage has occurred.

Adult↗

Comparison of different rates of artificial ventilation in preterm neonates with respiratory distress syndrome.

The effectiveness of three different ventilator rates of artificial ventilation (30, 60 and 120/min) was studied in 32 preterm infants, all of whom were suffering from the Respiratory Distress Syndrome (16 were paralysed). Ventilator pressures, I:E ratio and MAP were kept constant at each rate. Increase in rate from 30 to 60 and to 120/min was well tolerated and not associated with episodes of hypotension. The only significant improvement in oxygenation was amongst the non-paralysed infants and at a rate of 120/min (p less than 0.01) this was associated with synchronous respiration. Two different ventilators were used in the study and a significant change in PaCO2 (reduction) occurred only in non-paralysed infants ventilated at a rate of 120/min by Sechrist ventilators (p less than 0.05). This difference may be a direct reflection of differences in ventilator performance at fast rates.

Airway Resistance↗

Synchronous respiration: which ventilator rate is best?

Twenty-four infants were ventilated through a series of rates (30, 60 and 120/min), to determine which rate was most successful in provoking synchronous respiration. Their spontaneous respiratory rate was also documented during a temporary disconnection from the ventilator: respiratory rate and gestational age were significantly correlated (r = -0.85). Seventeen infants showed synchronous respiration at a ventilator rate of 120/min and 4 at 60/min. Of the remaining 3 infants, 2 only showed synchrony if ventilated at their own spontaneous respiratory frequency (between 60-75/min) and 1 infant was asynchronous at all rates including her own spontaneous respiratory frequency. The 17 infants synchronous at a ventilator rate of 120/min were significantly less mature (p less than 0.01) and had a faster spontaneous respiratory rate (p less than 0.01) than the 6 infants synchronous at ventilator rates of 60-75/min.

Airway Resistance↗

Prognosis of the very low birthweight baby in relation to gender.

The effects of gender on mortality and morbidity of all neonates weighing less than 1500 g admitted to King's College Hospital Neonatal Intensive Care Unit during 1980-82 (n = 271) were examined. Very low birthweight boys had a significantly higher mortality and more postnatal complications than girls. The higher incidence of respiratory distress syndrome and pulmonary interstitial emphysema in boys was associated with increased mortality in the first year. Surviving boys had significantly more problems, including lower Apgar scores at five minutes, more frequent apnoeic attacks and bradycardic episodes, transient tachypnoea, neonatal anaemia, and lower blood calcium and phosphate concentrations. Surviving children were followed up at 1 and 2 years of age. Development of boys at 1 year was significantly delayed compared with girls in all fields save locomotor. Although at 2 years some of the differences had diminished, those in language and personal social skills were more pronounced. More than twice as many boys as girls had major neurodevelopmental disorders.

Child Development↗

Chlamydia trachomatis as a cause of neonatal conjunctivitis.

Chlamydia trachomatis was identified in 37 of 73 consecutive neonates with purulent conjunctivitis, including four delivered by caesarean section with intact membranes. Most (28/37) presented in the first week. Infection was significantly associated with referral from the community. Genital C. trachomatis infection was present in 13 of 35 parents of affected infants.

Chlamydia trachomatis↗