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Biomedical subjects

H R Gamsu

Publications and source records attributed to H R Gamsu.

At least 37 records · Page 2Linked to original sources

Randomized trial of umbilical arterial catheter position: clinical outcome.

In order to determine if umbilical arterial catheter position affects the incidence of necrotizing enterocolitis, clinical outcome was analysed in 308 infants whose umbilical arterial catheter had been randomly allocated to a high (n = 162) or a low (n = 146) position. Necrotizing enterocolitis was classified as suspected or confirmed; all renal, lower limb and local catheter complications were also recorded. High umbilical arterial catheters were in place for longer than low catheters, provided more samples and were removed as an emergency less often. Lower limb blanching and cyanosis were more common with low catheters. Eleven cases of confirmed necrotizing enterocolitis occurred in the "high" group and nine in the "low" group. One case of fatal aortic thrombosis was encountered in the high group. Positioning umbilical arterial catheters in a high position allowed longer functional use and did not increase the incidence of necrotizing enterocolitis.

Catheterization↗

Renal artery blood flow velocity in very low birthweight infants with intrauterine growth retardation.

Doppler ultrasound was used to measure left renal artery blood flow velocity and pulsatility index on the first, third, and seventh day of postnatal life in 18 very low birthweight small for gestational age (SGA) infants. The values were compared with those from 18 weight matched and 18 gestation matched controls. SGA infants had significantly lower blood flow velocity than their gestation matched controls throughout the first postnatal week (day 1: SGA 10 cm/s, controls 15 cm/s; day 7: SGA 17 cm/s, controls 28 cm/s). These data suggest that abnormalities of renal artery blood flow velocity persist after delivery in the SGA infant.

Blood Flow Velocity↗

Changes in cerebral artery blood flow velocity after intermittent cerebrospinal fluid drainage.

Doppler ultrasound was used to measure blood flow velocity in the anterior cerebral artery of six premature infants with posthaemorrhagic hydrocephalus, before and after intermittent cerebrospinal fluid (CSF) drainage, on 23 occasions. There was a significant increase in mean blood flow velocity after the drainage procedures (+5.6 cm/s, 95% confidence interval +2.9 to +8.3 cm/s), which was accompanied by a decrease in velocity waveform pulsatility. CSF pressure also fell significantly. In patients with posthaemorrhagic hydrocephalus, intermittent CSF drainage was associated with acute changes in cerebral haemodynamics.

Blood Flow Velocity↗

Vitamin A status in preterm and term infants at birth.

Vitamin A status was determined in infants born at term or prematurely to assess if vitamin A levels at birth were related to gestational age. Vitamin A levels were measured in cord blood samples from 13 infants born at term and in blood samples obtained within two hours of birth in 26 preterm infants (median gestational age 31 weeks, range 27-35). None of the preterm infants developed chronic lung disease. The vitamin A levels of the term infants (median 0.71 mumol/l, range 0.34 to 1.27) were significantly higher than those of infants born preterm (median 0.35 mumol/l, range 0.12 to 1.22), p < 0.01. Vitamin A levels correlated significantly with gestational age (vitamin A level = 0.024 gestational age (weeks) -0.23, r = 0.39, p < 0.02. We thus conclude that gestational age must be taken into account when interpreting vitamin A levels.

Chronic Disease↗

Antenatal diagnosis and outcome in hydrops fetalis.

The records of 15 cases of hydrops fetalis consecutively delivered at our institution were reviewed to determine the accuracy of antenatal diagnosis and whether antenatal diagnostic techniques yielded information useful in predicting outcome. All 15 cases were detected antenatally, five were due to rhesus haemolytic disease and 10 were non-immune hydrops. All the infants required active resuscitation. Ten infants eventually died, two had immune hydrops fetalis and 8 non-immune hydrops. Seven infants had pleural effusions, all had been detected antenatally. The presence of pleural effusions did not influence mortality. All structural abnormalities were accurately detected in those patients seen prior to labour and there were no survivors in the group of infants so affected. We conclude that the mortality of non-immune hydrops fetalis remains high and that antenatal diagnosis of this condition is accurate and provides useful prognostic information.

Female↗

Vitamin A levels at birth of high risk preterm infants.

Vitamin A levels were measured shortly after birth in preterm infants at high risk of developing chronic lung disease (CLD). Eleven infants, median gestational age 24 weeks, developed CLD. Their results were compared to 11 infants who, although they required mechanical ventilation for at least 48 hours, did not develop CLD. The median gestational age of this latter group was 30 weeks (range 27-35). The median vitamin A level of the infants who developed CLD was 0.62 umol/l (range 0.41-0.95), which was significantly higher than the median level of the infants who did not develop CLD, which was 0.36 umol/l (range 0.13-0.89). We conclude preterm infants who develop CLD are not predisposed to develop that complication by low vitamin A levels at birth.

Chronic Disease↗

Neonatal complications of extreme prematurity in mechanically ventilated infants.

Previous data have suggested that neonatal complications amongst preterm ventilated infants increase with decreasing gestational age and thus are likely to be greatest among ventilated infants of less than 28 weeks gestational age. The aim of this study was to test that hypothesis, thus we report the neonatal complications of 175 extremely preterm mechanically ventilated infants (gestational age less than or equal to 28 weeks). Of the infants 152 were ventilated because of respiratory distress syndrome (RDS) or respiratory distress of severe prematurity, 41% of these infants died. Amongst infants with RDS or respiratory distress of extreme prematurity, mortality was significantly increased in infants of gestational age less than or equal to 24 weeks and birth weight less than or equal to 1000 g. In this group 20% developed a pneumothorax, and mortality was inversely related to gestational age. In infants with RDS, 43% developed a periventricular haemorrhage and 37% were still oxygen-dependent at 28 days of age; neither of these complications was significantly related to birth weight or gestational age. Of infants with RDS 38% developed a patent ductus arteriosus and 16% developed retinopathy of prematurity. These data suggest that even amongst very immature infants there has been an impressive reduction in the neonatal complications of mechanical ventilation.

Gestational Age↗

Ventilatory requirements for respiratory distress syndrome in small-for-gestational-age infants.

Neonatal ventilatory requirements and outcome were examined in 135 very preterm, small-for-gestational age (SGA) infants to determine whether fetal growth retardation protects against severe respiratory distress syndrome (RDS) in very immature infants. Their results were compared to those from gestational age- and gender-matched controls. Although there was no significant difference in the median duration of mechanical ventilation between the two groups, more SGA infants required ventilation and were ventilated because of RDS. In a subgroup also matched for mode of delivery, there was no significant difference between the proportion of SGA infants requiring mechanical ventilation for RDS compared to their matched controls. The mortality was greater in the SGA group. We conclude that fetal growth retardation does not protect against severe RDS.

Birth Weight↗

Dexamethasone and hypertension in preterm infants.

The magnitude and duration of the effect of dexamethasone on systolic blood pressure has been examined in 13 very preterm infants (median gestational age 25 weeks). All had chronic lung disease (CLD). To exclude any effect of CLD on blood pressure each infant acted as his or her own control. Systolic blood pressure increased in all infants (P less than 0.01) and remained elevated for at least 48h following cessation of therapy. The median maximum increase in blood pressure was 24 mmHg (range 13-49 mmHg) and occurred on day 4 (median, range 2-10) of treatment. One infant developed hypertensive encephalopathy. These results demonstrate the need to monitor infants with CLD throughout steroid therapy and preferably for some days after it has ceased.

Chronic Disease↗

Nosocomial bacterial infections in very low birth weight infants.

The occurrence of congenital and nosocomial bacterial septicaemia has been documented by identifying the number of positive blood cultures by reviewing the laboratory and clinical records of 394 very low birth weight infants who were consecutively admitted to a neonatal intensive care unit over a 40-month period. The incidence of congenital septicaemia was 6% and of nosocomial septicaemia 17%. The commonest causes of congenital infection were Streptococcus agalactiae Staphylococcus epidermidis and Enterococcus faecalis (each in 18% of cases). The commonest cause of nosocomial infection was S. epidermidis (51% of cases), except in infants of birth weight less than 750 g. Risk factors for nosocomial infection were extremely low birth weight, very preterm birth and prolonged ventilation. Nosocomial infection was associated with significantly lengthened hospital admission.

Cross Infection↗

Congenital bacterial sepsis in very preterm infants.

The results of body fluid and surface cultures from 148 preterm infants less than 33 weeks gestational age obtained routinely on admission to a neonatal intensive care unit were reviewed. The aim was to determine the occurrence of congenital bacterial sepsis in this population and to examine whether surface cultures yielded information helpful in management. Gastric aspirate and umbilical, nasal and ear swabs were cultured and the results were compared to those of blood cultures. Nine infants (5.4%) had congenital bacterial sepsis diagnosed by positive blood cultures. Only the results of microscopy of gastric aspirate were available within hours of birth and before the results of blood culture. Microscopy of gastric aspirate, demonstrating pus cells, alone had a sensitivity of 0.86 in predicting congenital sepsis but a specificity of 0.49; the specificity, however, rose to 0.80 if both organisms and pus cells were observed on microscopy. Thus, only this combination was a useful pre-indicator of congenital sepsis. In infants who did not develop septicaemia, treatment was modified only if Streptococcus agalactiae was cultured from surface sites; in all such cases, the organism was grown from the ear swab. Our results demonstrate that congenital bacterial sepsis is common amongst very preterm infants admitted for neonatal intensive care but routine screening of surface cultures should be restricted to an ear swab only.

Bacterial Infections↗

Randomised controlled trial of colloid infusions in hypotensive preterm infants.

Colloid infusions are often given to treat hypotension in preterm infants. The aim of this work was to assess whether it was the amount of protein or the volume of the colloid infused which accounted for the observed increase in blood pressure. Sixty preterm infants were randomised (20 in each group) to receive 5 ml/kg 20% albumin, 15 ml/kg fresh frozen plasma, or 15 ml/kg 4.5% albumin. All infusions were given at a rate of 5 ml/kg/hour in addition to maintenance fluids. The infants were randomised when hypotensive (systolic blood pressure less than 40 mm Hg for two hours). There was no significant difference in the blood pressure of the three groups before or one hour after beginning the infusion. The mean increase in blood pressure one hour after completing the infusion, however, was significantly lower in infants receiving 20% albumin: 9% compared with 17% in the group receiving 4.5% albumin, and 19% in the group receiving fresh frozen plasma. It is concluded that the volume infused rather than albumin load is important in producing a sustained increase in blood pressure.

Albumins↗

Superior mesenteric artery blood flow velocity in necrotising enterocolitis.

Doppler measurements of blood flow velocity were obtained from the superior mesenteric artery (SMA), coeliac axis, and anterior cerebral artery (ACA) of 19 infants with suspected necrotising enterocolitis, which was classified as confirmed (n = 9) or unconfirmed (n = 8). Infants with confirmed disease were compared with controls who were either enterally fed or who were receiving intravenous fluids. SMA velocity was significantly higher in the infants with confirmed necrotising enterocolitis (36.5 cm/s) than in unfed controls (20.4 cm/s) or infants with unconfirmed enterocolitis (19.6 cm/s). Three infants with confirmed disease had data from before the onset of symptoms. One had low SMA velocity on the first day of life, and one showed no increase in SMA velocity after enteral feeds were started. SMA velocity is increased when infants develop symptoms of necrotising enterocolitis, suggesting that total gut ischaemia is not present at the time that the disease is clinically apparent, although it may precede the onset of symptoms and play a part in the pathogenesis of the disorder.

Blood Flow Velocity↗

Complement activation in neonatal infection.

To investigate the usefulness of indices of complement activation in the diagnosis of infections in the neonatal period, activation products C4d, Ba, and C3d were measured in 42 babies with a putative diagnosis of infection based on clinical/laboratory criteria, and compared with conventional clinical and haematological criteria of infection and with C reactive protein. The diagnosis of sepsis was confirmed by culture and identification of organisms in 17. Fourteen babies in whom infection was not suspected formed the control group. In babies with proved infection, concentrations of the fragments C4d, Ba, and C3d were higher than in babies with suspected infection in whom microbiological tests were negative, and concentrations of Ba and C3d were higher than in controls. C reactive protein and the platelet count were not significantly different in babies with proved infection and those with negative microbiological tests, but in the latter, C reactive protein concentrations were higher than in controls. Of the indices studied, high concentrations of Ba predicted microbiologically proved infection with the highest sensitivity (47.1%) and specificity (92.0%). Ba thus seems to be useful as an early indicator of infection in the neonatal period.

Analysis of Variance↗

Randomised trial of umbilical arterial catheter position: Doppler ultrasound findings.

Umbilical arterial catheters (UAC) were randomly assigned in 69 infants to a high (n = 36) or to a low (n = 33) position. Serial Doppler ultrasound measurements of blood flow velocity in their superior mesenteric arteries, coeliac axis, renal arteries, and anterior cerebral arteries were then obtained. There were no differences in blood flow velocity between high and low UAC groups on days 1, 3, and 7. At 2 weeks, those infants with a high UAC still in place had significantly higher velocities in the mesenteric artery than those infants who had no catheter in place. Infants with high UACs remaining in place for more than 7 days were found to have an increase in abdominal distension and tenderness, whereas this was not the case for those with low UACs. Catheter position has no effect on visceral blood flow if the UAC stays in place for one week or less, whereas prolonged use of a high UAC may alter intestinal blood flow and increase the incidence of abdominal symptoms.

Blood Flow Velocity↗

Salbutamol infusion to treat neonatal hyperkalaemia.

Salbutamol infusion, 4 micrograms/kg in 5 ml of water infused for 20 minutes, was given to treat hyperkalaemia (potassium level > 6.0 mmol/l) in 10 critically ill preterm infants (median gestational age 26 weeks). Seven infants had acute renal failure, two had persistent metabolic acidosis without renal failure and the remaining infant had a combination of acute renal failure and persistent metabolic acidosis. No infant developed a tachycardia or became hyperglycaemic in response to the infusion. Seven of the 10 infants ultimately died but this was at a mean of 9 days following the infusion and as a consequence of complications due to their extreme prematurity or major congenital abnormality. In response to the infusion the potassium level fell in 7 infants with acute renal failure by a median of 1.1 mmol/l (range 0.7-1.8) at one hour but in the three infants with a persistent metabolic acidosis, the potassium level continued to rise. We conclude that salbutamol infusion achieves, without side-effects, at least a temporary reduction in hyperkalaemia in preterm infants with renal failure, but not metabolic acidosis. Its effect is of sufficient duration to allow ample time for definitive therapy to be instituted and thus may be a useful alternative for infants in whom the possible hypoglycaemic side-effects of glucose and insulin should be avoided.

Acidosis↗

Home oxygen therapy following neonatal intensive care.

In a 12-month period 28 of 164 consecutive very low birthweight (VLBW) infants receiving intensive care within 48 h of birth at King's College Hospital developed chronic lung disease, (oxygen dependence beyond 28 days of age). Fifteen of the 28 infants were eligible for home oxygen therapy, but this was only practical, because of home circumstances, in 8 infants (4.9%). These 8 infants received home oxygen therapy. One further infant, born at term and suffering from pulmonary hypoplasia was also discharged home on oxygen therapy. Two infants subsequently required readmission due to a deterioration in their respiratory status and died. Three others required re-admissions (total duration 32 days) for respiratory problems. The median duration of home oxygen therapy was 17 weeks (range 4-486 days). We conclude that home oxygen therapy is needed by only a very small number of preterm infants and is appropriate for only a proportion of them. Parents need to be counselled carefully regarding the possibility that the need for oxygen might be protracted.

Home Nursing↗

Inflating pressures for effective resuscitation of preterm infants.

The magnitude of inflating pressure necessary for effective resuscitation was examined in 70 preterm infants. The median pressure to cause adequate chest wall expansion was 22.8 cmH2O; no infant required a peak inflating pressure greater than 30 cmH2O. No further increase in inflation pressure was used during resuscitation and the median 5- and 10-min Apgar scores were 8 and 9, respectively.

Humans↗