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F D Dykes

Publications and source records attributed to F D Dykes.

15 recordsLinked to original sources
PubMed1996

Intraventricular hemorrhage and high-frequency ventilation: a meta-analysis of prospective clinical trials.

OBJECTIVE: The association between high-frequency ventilation (HFV) and intraventricular hemorrhage (IVH) and periventricular leukomalacia (PVL) has been debated. PURPOSE: To determine if premature neonates treated with HFV are at greater risk for developing IVH and/or PVL than neonates treated with conventional ventilation, we completed a meta-analysis of all prospective randomized control trials comparing HFV and conventional ventilation in the management of respiratory distress syndrome. METHODS: The meta-analysis included nine studies comparing HFV and conventional ventilation in the management of preterm neonates. To summarize the data, we calculated the difference in absolute risk for IVH and PVL between neonates treated with HFV and those treated with standard ventilation. These differences were combined to determine an overall difference in the absolute risk and its confidence interval. We examined the effect of estimated gestational age, birth weight, surfactant, and age at study entry on the results. Because one trial (HIFI study) was much larger than the other studies, it dominated the analysis, so we evaluated the data with and without including data from the HIFI trial. RESULTS: The occurrences of IVH and PVL ranged from 14% to 47% and 5% to 16%, respectively. This variation may be explained by the difference in the populations of neonates treated. The meta-analysis showed that use of HFV was associated with an increased risk of PVL (odds ratio = 1.7 with a confidence interval of 1.06 to 2.74), but not IVH or severe (> or = grade 3) IVH. When the results of the HIFI study were excluded, there were no differences between HFV and conventional ventilation in the occurrence of IVH or PVL. CONCLUSIONS: The association between HFV and adverse neurologic outcomes is primarily influenced by the results of the HIFI trial. Meta-analysis of more recent studies does not confirm the findings of the HIFI trial and suggests that HFV is not associated with increased occurrence of IVH or PVL.

Cerebral Hemorrhage↗
PubMed1993

Extracorporeal membrane oxygenation service at Egleston: two years' experience.

Extracorporeal membrane oxygenation (ECMO) is a perfusion support procedure that has been used to treat more than 7,000 patients with life threatening cardiac and/or respiratory failure. After 6 months of training and preparation, an ECMO service was opened on January 2, 1991, in Egleston Children's Hospital at Emory University. During the first 2 years, 96 neonatal, 31 pediatric, and 8 cardiac patients have been referred for possible ECMO. Of these 135 patients, 21 had disqualifying conditions. Sixty-four were considered candidates for ECMO but were able to be supported using less invasive therapies; only one of these died. Fifty patients were treated with ECMO of whom 39 survived (78%). Survival rates for neonatal, pediatric, and cardiac cases as separate groups as well as for each diagnostic category within these groups compare favorably with those reported by the international ELSO Registry. Notable in this series is the fact that 26/35 neonatal patients and 7/10 pediatric patients were successfully supported using venovenous (VV) rather than venoarterial (VA) perfusion, with the major indication for venoarterial ECMO being inability to introduce the 14F venovenous catheter into the patient's internal jugular vein. No patient initially managed with VV ECMO required conversion to VA. It is anticipated that avoidance of carotid ligation along with other innovations, such as the impending commercial availability of heparin-coated ECMO circuits, will make ECMO a highly attractive and appropriate therapy for an increasing number of high risk neonatal and pediatric patients in our state and region.

Adolescent↗
PubMed1989

Posthemorrhagic hydrocephalus in high-risk preterm infants: natural history, management, and long-term outcome.

The natural history, medical management, and outcome in infants with progressive posthemorrhagic hydrocephalus after intraventricular hemorrhage were studied prospectively. Infants with asymptomatic severe posthemorrhagic hydrocephalus were managed with a predetermined protocol. Outcome between groups at 1 to 2 years and at more than 3 years was compared. The natural history study, restricted to the inborn population, revealed that posthemorrhagic hydrocephalus developed in 53 of 409 infants with intraventricular hemorrhage. The progression of hydrocephalus either was arrested or regressed in 35 of 53 infants; progression to severe hydrocephalus occurred in 18 of 53 infants. The severe posthemorrhagic hydrocephalus was asymptomatic in 16 of 18 infants. The management and outcome study included both inborn and outborn infants. Of 50 infants, 12 had symptomatic severe hydrocephalus and 38 had asymptomatic severe hydrocephalus. The 16 infants managed with close observation were as likely to remain shunt free as the 22 infants managed with serial lumbar punctures. Of 38 infants, 20 were managed without shunts. At 3 to 6 years, the outcome of infants in the close observation group did not differ from that in the lumbar puncture group. Long-term outcome of infants with progression to asymptomatic severe hydrocephalus did not differ from that of infants in whom disease progression was arrested. Poor outcome in infants with intraventricular hemorrhage and subsequent posthemorrhagic hydrocephalus was related to severity of hemorrhage and gestational age at birth less than 30 weeks. Because long-term outcome of infants with severe hydrocephalus did not differ from that of infants in whom the progression of hydrocephalus was arrested or whose condition improved before hydrocephalus became severe, we currently attempt medical management of these infants.

Brain Damage, Chronic↗
PubMed1989

Heart rate variability analysis in full-term infants: spectral indices for study of neonatal cardiorespiratory control.

The heart rate and respirations of twenty healthy full-term infants between 30 and 60 h postnatal age were studied during quiet sleep with the objective of defining spectral indices which represent normal neonatal heart rate variability (HRV) characteristics. Total HRV power and the distribution of power across different frequency bands varied considerably among infants. Cluster analysis on the measured variables indicated that the population divided into two groups that represented significantly different patterns of HRV behavior. In one group (11 subjects), infants had lower breathing rates and HRV power in a band about the respiration frequency [respiratory sinus arrhythmia (RSA) band] was more than 20% of the total power (TP). Additionally, the ratio of low frequency band power to RSA band power was less than 4. The other group of neonates (nine subjects) had relatively higher breathing rates, RSA power less than 20% of total power, and low frequency to RSA power ratio greater than 4. Regression analysis of low frequency versus TP and RSA versus TP graphs gave strong support to the hypothesis that there were indeed two distinct patterns of HRV behavior. Separation of apparently normal neonates into two groups may be attributed partially to differences in respiratory rates and breathing patterns. However, it is possible that differences in the balance between sympathetic and parasympathetic nervous system control, perhaps related to autonomic maturation, also contribute to group separation. The indices developed from HRV spectral analysis in this investigation may be of value in the study of cardiorespiratory control in neonates.

Arrhythmia, Sinus↗
PubMed1986

Breath amplitude modulation of heart rate variability in normal full term neonates.

The relationship between heart rate variability and respiration patterns was investigated using spectral analysis techniques in nine full-term infants whose ages ranged from 39-75 h. All the infants were studied during sleep, although no attempt was made to classify rapid eye movement or nonrapid eye movement states prospectively. The data obtained were examined to determine which aspects of neonatal breathing patterns are correlated with heart rate variability. Three spectral regions of heart rate variability could be identified: a very low frequency region below 0.02 Hz; a low frequency region from 0.02-0.20 Hz; and a high frequency region above 0.20 Hz. The dominant heart rate variability activity in these neonates was seen in the very low and low frequency regions, with little activity in the high frequency regions. In contrast to older infants and adults, respiration and heart rate variability were not strongly related through a high frequency region respiratory sinus arrhythmia but rather through a breath amplitude sinus arrhythmia which occurs in the low frequency region of the spectrum. The prominent very low frequency activity and the low frequency activity ascribed to breath amplitude modulation may result from autonomic nervous system mediation of chemoregulation.

Arrhythmias, Cardiac↗
PubMed1983

Range-gated pulsed Doppler ultrasonographic evaluation of carotid arterial blood flow in small preterm infants with patent ductus arteriosus.

Range-gated pulsed Doppler (RGPD) ultrasonography was utilized to study the effect of a patent ductus arteriosus (PDA) on carotid arterial blood flow in small preterm infants. Carotid arterial flow velocity studies were performed on 23 preterm infants, sampling right and left carotid arteries. Studies on seven infants after PDA ligation and on seven who developed no evidence of PDA were used as controls. A strong relationship was demonstrated between diastolic reversal in the carotid arteries and PDA. The results of this study indicate that the RGPD flow velocity curve from the carotid artery is more sensitive than M-mode echocardiography or clinical examination in detecting PDA, and that PDA in small preterm infants is associated with a distinct abnormality in the carotid arterial flow pattern.

Blood Flow Velocity↗
PubMed1983

Relationship between pressure passivity and subependymal/intraventricular hemorrhage as assessed by pulsed Doppler ultrasound.

A prospective study was undertaken using a range-gated, pulsed Doppler velocimeter to study flowpressure relationships in the anterior cerebral artery. Serial velocity and pressure studies were performed with each infant serving as his or her own control. The hypothesis tested was that ill preterm infants sustaining subependymal/intraventricular hemorrhage would have absent autoregulation. The hypothesis has been tested in 88 studies on 32 infants. Of 32 infants studied, 15 were judged to be pressure passive; nine of these children bled. The other 17 infants were not pressure passive; eight of these children bled (P greater than .05). From these studies, it may be concluded that the pressure passive state is not the final common link in the genesis of subependymal/intravertricular hemorrhage. Pulsed Doppler ultrasound may provide an extremely useful noninvasive technique for studying both the arterial and venous sides of the cerebral circulation.

Blood Flow Velocity↗
PubMed1980

Intraventricular hemorrhage in the high-risk preterm infant: incidence and outcome.

To determine the incidence of subependymal (SEH) or intraventricular hemorrhage (IVH) and its short-term outcome, infants of less than 35 weeks' gestation who required intensive care were evaluated and computerized tomographic scans obtained. If the scans showed blood, serial scans were followed until the hemorrhage had resolved and ventricle size was stable. Hemorrhage was quantitated; Seventy-seven of 191 (40.3%) infants were shown to have SEH, IVH, or both; 22 of them (28%) died, and hemorrhage was thought to be the primary cause of death in 17. Fifty-five survivors (71%) with SEH, IVH, or a combination of the two had serial follow-up scans. Six had SEH alone; 49 had IVH. Severe progressive hydrocephalus developed in 12 (22%) infants. Thirty-seven (75.5%) die not show progressive hydrocephalus. The degree of hemorrhage in these 37 was mild in 14, moderate in 13, and marked in 10. Of those with progressive hydrocephalus, hemorrhage was marked in 8 and moderate in 4. Hydrocephalus resolved spontaneously in 4 of the 12. Medical treatment (repeated lumbar punctures) was successful in 3, but failed in 4. Hydrocephalus was managed by shunt surgery in 5. This study revealed that the quantity of blood is prognostically important with regard to both survival (p less than 0.001) and development of progressive hydrocephalus (p less than 0.05). Furthermore, hydrocephalus, even if progressive, may not necessitate surgical management;

Cerebral Hemorrhage↗
PubMed1980

Intraventricular hemorrhage: a prospective evaluation of etiopathogenesis.

In a study population of 151 newborn infants less than 35 weeks gestation, who required intensive care for more than 24 hours, clinical and biochemical factors associated with the presence of intraventricular hemorrhage (IVH) were prospectively evaluated. The diagnosis of IVH was confirmed by computed tomography, ventricular tap, or autopsy. Alveolar rupture was highly correlated with the presence of IVH. Other factors associated with IVH were: hypoxemia, hypercarbia, mechanical ventilation, peak inflation presser > 25 cm H2O, inspiratory to expiratory ratio > 1:1, patent ductus arteriosus, bicarbonate administration after the first day of life, volume expansion in the first day of life, hypotension, stages III and IV hyaline membrane disease, and intrauterine growth retardation. Early bicarbonate administration (first day), sodium administration > 8 mEq/kg/day, acidosis and birth weight less than or equal to 1,200 gm were associated with IVH only in the infants who died with IVH. Factors not associated with IVH were Apgar less than or equal to 5 at one and five minutes, birth weight, gestational age, male sex, osmolality greater than or equal to 300, serum sodium greater than or equal to 150, hypothermia, continuous distending pressure > 6 cm H2O, positive end-expiratory pressure > 5 cm H2O, outborn birth, obstetric trauma, or coagulopathy. Certain therapeutic interventions may lead to an increase incidence of intracerebral hemorrhage in the high-risk preterm infant.

Cerebral Hemorrhage↗