Biomedical subjects

D A Osborn

Publications and source records attributed to D A Osborn.

At least 37 records · Page 2Linked to original sources

PubMed2000

Kinesthetic stimulation for treating apnea in preterm infants.

BACKGROUND: This section is under preparation and will be included in the next issue. OBJECTIVES: Main question: in preterm infants with apnea, does the use of kinesthetic stimulation lead to clinically important reductions in clinical apnea and bradycardia (>50% reduction in number of episodes), use of mechanical ventilation (IPPV) or continuous positive airways pressure (CPAP), and neurodevelopmental disability, without clinically important side effects. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register, MEDLINE, previous reviews including cross references, abstracts, conferences, symposia proceedings, expert informants, and journal handsearching mainly in the English language. SELECTION CRITERIA: All trials using random or quasi-random patient allocation in which kinesthetic stimulation in preterm infants was compared to placebo or no treatment for apnea of prematurity were included. DATA COLLECTION AND ANALYSIS: Standard methods of the Cochrane Collaboration and its Neonatal Review Group were used with separate evaluation of trial quality, data extraction by both authors and synthesis of data using relative risk and weighted mean difference. As all three trials were crossover trials, the data were extracted from all exposure periods and combined where appropriate. Measures of severity of apnea as well as the response to treatment were consistent with an evaluation of 'clinical apnea', as defined by the American Academy of Pediatrics (Nelson 1978). MAIN RESULTS: Three crossover studies (Korner 1978, Tuck 1982 and Jirapaet 1993) were identified that compared a form of kinesthetic stimulation to control for the treatment of apnea of prematurity. Clinically significant apnea: None of the three studies showed an important reduction (>50%) in clinical apnea. Using a lower threshold (>25%), the study by Korner 1978 found less apnea and bradycardia in infants receiving kinesthetic stimulation. Tuck 1982 demonstrated reductions in the frequencies of apneas (> 12 seconds) associated with bradycardia (< 100 bpm), apneas associated with hypoxia (TcP02 < 50 mmHg), and apneas requiring stimulation in infants on the rocking bed. Individual patient data were not available from the author to determine if there was an important reduction in clinical apnea. No outcome could be extracted from the study by Jirapaet 1993 that was consistent with the definition of clinically important apnea. Other events: No significant differences were found in the incidence of infants requiring resuscitation, IPPV, CPAP or respiratory stimulants whilst receiving treatment. Adverse events such as death, intraventricular hemorrhage and neurodevelopmental follow up were not reported. REVIEWER'S CONCLUSIONS: There is insufficient evidence to recommend kinesthetic stimulation as treatment for clinically significant apnea of prematurity. Previous reviews have suggested that kinesthetic stimulation is not effective at preventing apnea of prematurity (Henderson-Smart and Osborn 1998) and is not as effective as theophylline at treating clinically significant apnea of prematurity (Osborn and Henderson-Smart 1998).

Apnea↗

PubMed2000

Kinesthetic stimulation versus theophylline for apnea in preterm infants.

BACKGROUND: Apnea of prematurity may lead to hypoxemia and bradycardia requiring resuscitative measures being instituted. Many treatments have been used in infants with apnea of prematurity, such as theophylline. Kinesthetic stimulation, which uses various forms of oscillating mattress, might also prevent apnea without using a standard drug such as theophylline. OBJECTIVES: Main question: in preterm infants, how does kinesthetic stimulation compare with methylxanthine therapy in the treatment of apnea of prematurity. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register, MEDLINE, previous reviews including cross references, abstracts, conferences and symposia proceedings, expert informants and journal handsearching mainly in the English language. SELECTION CRITERIA: All trials using random or quasi-random patient allocation, in which kinesthetic stimulation was compared to methylxanthine therapy for apnea of prematurity, were eligible. No trials were excluded from the review that met these criteria. DATA COLLECTION AND ANALYSIS: Standard methods of the Cochrane Collaboration and its Neonatal Review Group were used with separate evaluation of trial quality, data extraction by both authors and synthesis of data using relative risk and weighted mean difference. MAIN RESULTS: A single small study of 20 infants (Saigal 1986) demonstrated a significant benefit to the infants receiving theophylline compared to those on an oscillating water bed in terms of mean rates of clinically important apnea (apnea > 14 seconds and bradycardia < 100, and cyanosis or receiving stimulation). There were no significant differences in adverse effects (death, sleep states, the Albert Einstein Neurobehavioural Index, adverse neurological outcomes, and the Bayley Mental Development Index at six and 12 months), although the infants on the OWB had a higher psychomotor index at six but not 12 months. There were some differences between the groups in incidence and severity of respiratory distress syndrome, and baseline apnea rates. REVIEWER'S CONCLUSIONS: The results of this review should be treated with caution. Theophylline has been shown in one small study to be superior to kinesthetic stimulation at treating clinically important apnea of prematurity. There are currently no clear research questions regarding the comparison of methylxanthines and kinesthetic stimulation to treat apnea of prematurity.

Apnea↗

PubMed2000

Thyroid hormone for preventing of neurodevelopmental impairment in preterm infants.

BACKGROUND: Observational studies have shown an association between transiently low thyroid hormone levels in preterm infants in the first weeks of life (transient hypothyroxemia) and an abnormal neurodevelopmental outcome. Thyroid hormone therapy might prevent this morbidity. OBJECTIVES: To assess whether thyroid hormone therapy in preterm infants without congenital hypothyroidism results in clinically important changes in neonatal and long term outcomes in terms of both benefits and harms. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register, MEDLINE, previous reviews including cross references, abstracts, conferences, symposia proceedings, expert informants and journal handsearching in the English language. SELECTION CRITERIA: All trials using random or quasi-random patient allocation, in which thyroid hormone therapy (either treatment or prophylaxis) was compared to a control in premature infants. DATA COLLECTION AND ANALYSIS: Primary clinical outcomes included measures of neurodevelopmental outcome and mortality. Assessment of trial quality, data extraction and synthesis of data, using relative risk (RR) and weighted mean difference (WMD), were performed using standard methods of the Cochrane Collaboration and its Neonatal Review Group. MAIN RESULTS: Eight studies were identified that compared thyroid hormone treatment to control. Four randomized or quasi-randomized studies met inclusion criteria (Chowdhry 1984, Amato 1989, van Wassenaer 1997 and Vanhole 1997). All studies enrolled preterm infants < 32 weeks gestation, but used different timing, dose and duration of treatment with thyroid hormones. Three studies used thyroxine, whereas Amato 1989 used triiodothyronine. Only two studies with neurodevelopmental follow-up were of good methodology (van Wassenaer 1997 and Vanhole 1997). All studies were of small size with the largest, van Wassenaer 1997, enrolling 200 infants. A lack of comparability of data (neurodevelopmental test or timing of follow-up) prevented meta-analytic pooling of the studies for neurodevelopmental outcomes. There was no significant difference in mortality to discharge (typical relative risk 0.74, 95% CI 0.44, 1.26) in infants who received thyroid hormone treatment compared to controls. In individual studies, no significant differences were found in neurodevelopmental outcomes including risk of abnormal neurological outcome, and Bayley Mental or Psychomotor Development Indices. No data were available for the incidences of cerebral palsy or sensorineural impairment. Fraction of inspired oxygen was lower in infants receiving triiodothyronine in one small quasi-randomized study (Amato 1989), but not in infants receiving thyroxine in a randomized study (Vanhole 1997). No other differences were found to suggest a reduced severity of respiratory distress syndrome in infants receiving early thyroid hormone therapy. REVIEWER'S CONCLUSIONS: This review does not support the use of thyroid hormones in preterm infants to reduce neonatal mortality, improve neurodevelopmental outcome or to reduce the severity of respiratory distress syndrome. The a posteriori subgroup analyses of data from one study (van Wassenaer 1997) which showed benefits in infants 24-25 weeks gestation should be treated with caution. The small number of infants included in trials incorporated in this review limits the power of the meta-analysis to detect clinically important differences in neonatal outcomes. Future trials should be of sufficient size to detect clinically important differences in neurodevelopmental outcomes. They should consider enrolling those infants most likely to benefit from thyroid hormone treatment such as infants born at less than 27 weeks gestation and use thyroid hormones as treatment instead of prophylaxis.

Developmental Disabilities↗

PubMed2000

Targeted early rescue surfactant in ventilated preterm infants using the click test.

OBJECTIVE: To determine whether use of the click test, a rapid bedside test of surfactant function, results in earlier and more appropriate surfactant administration in ventilated preterm infants than does usual early rescue treatment. STUDY DESIGN: Ventilated preterm infants (n = 126) with inspired oxygen >/=25% and mean airway pressure >/=7 cm H(2)O were randomized in gestational strata (<28 weeks and 28-36 weeks) to have surfactant therapy determined by the click test or by usual clinical and chest radiograph criteria. The treatment group had the click test performed on a tracheal aspirate as soon as possible after intubation and, if negative or equivocal (surfactant deficient), surfactant was given. The control group had surfactant given as soon as possible based on clinical and chest radiograph diagnoses of respiratory distress syndrome. RESULTS: In infants of <28 weeks' gestation, use of the click test resulted in significantly earlier surfactant therapy (median time: 50 vs 159 minutes) and a reduction in the number of infants receiving surfactant (48% vs 79%). In infants of 28 to 36 weeks' gestation, there was no difference in time to surfactant (median time: 300 vs 268 minutes) or in the number of infants receiving surfactant. Neonatal morbidity and mortality were similar in click test and control groups. CONCLUSIONS: Use of the click test in ventilated, extremely premature infants results in significantly earlier and more appropriately targeted administration of surfactant than does early rescue therapy based on clinical and radiograph criteria. A randomized trial of targeted early rescue surfactant therapy versus prophylactic surfactant therapy in infants of <28 weeks' gestation is warranted. The click test has the potential to improve clinical outcomes and reduce costs.

Diagnostic Techniques, Respiratory System↗

PubMed1999

Radiofrequency catheter ablation in a haemodynamically compromised premature neonate with hydrops fetalis.

A preterm infant was born at 35 weeks gestation after failed antenatal antiarrhythmic therapy. The infant had an incessant supraventricular tachycardia, impaired ventricular function and hypotension and failed to respond to adenosine, cardioversion and intravenous amiodarone. After resuscitation from cardiovascular collapse, a successful radiofrequency catheter ablation (RFA) of a left free wall atrioventricular pathway was performed at 24 h of age without extracorporeal support. The infant is normal on follow up at 12 months of age. Whilst most fetal and neonatal supraventricular tachyarrhythmias respond to antiarrhythmic medications and RFA is not required, this is the earliest RFA to be performed on a premature infant when antiarrhythmics have failed.

Catheter Ablation↗

PubMed1999

T and Tk antigen activation in necrotising enterocolitis: manifestations, severity of illness, and effectiveness of testing.

AIMS: To determine if T or Tk antigen activation is associated with different and more severe manifestations of illness in infants with necrotising enterocolitis (NEC); and if a policy of testing infants with suspected sepsis or NEC for T and Tk antigen activation is effective. METHODS: A case-control study of infants with confirmed NEC, born after the introduction of screening, was undertaken:17 activated infants were compared with 28 non-activated controls, matched for gestation and weight. A historical control study compared the outcome of infants before and after the introduction of testing. RESULTS: Of 201 infants with confirmed NEC, 27 were T or Tk antigen activated-10 (9%) before and 17 (19%) after the introduction of testing. T or Tk antigen activated infants had a significantly higher mortality (35% vs 7%); more frequent (71% vs 21%) and severe haemolysis, hyperkalaemia, renal impairment, acidosis; and they received more colloid for resuscitation. While only known activated infants in both time periods were managed with the use of low titre T antibody blood products, there was a significant increase in mortality (odds ratios 2.6; 95% CI 1.2, 5.6) and incidence of surgery (OR 2.7; 1.5, 4.9) after the introduction of testing. The increased mortality (OR 2.6; 0.8, 5.2) and incidence of surgery (OR 1.8; 0.9, 3.7) were no longer significant after adjustment for several perinatal risk factors. CONCLUSIONS: In a retrospective case-control study, routine testing of at risk infants increased the detection rate of T and Tk antigen activation. The use of low titre T plasma products in these patients did not reduce mortality compared with historical controls. A randomised controlled trial of testing in at risk infants, or of the use of low titre T plasma products in babies with NEC and T activation, is warranted.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed1998

Interobserver reliability of the click test: a rapid bedside test to determine surfactant function.

OBJECTIVE: To determine the interobserver reliability of the click test, a rapid bedside test of surfactant function. METHODOLOGY: One hundred samples (48 amniotic fluid, 28 gastric aspirates, 24 tracheal aspirates) were obtained from pregnant women, term and preterm infants managed at two perinatal centres. Gestational ages of the pregnancies or infants at time of sampling ranged from 24 to 40 weeks (mean +/- s.d.: 31+/-5). The click test was performed independently by two observers, with differing levels of experience, and blinded to each other's results. Interobserver reliability was determined for samples classified as negative (no clicking bubbles), equivocal (a few clicking bubbles seen after 2 min of looking), and positive (clicking bubbles seen easily on first look). As negative and equivocal test results suggest surfactant dysfunction, these results were also combined to provide a dichotomised result. RESULTS: For samples classified as negative, equivocal and positive the interobserver agreement was 0.83, with agreement beyond chance shown by a quadratic weighted Kappa of 0.74 (95% CI = 0.62-0.86). When negative and equivocal results were combined, the simple Kappa was 0.73 (95% CI = 0.59-0.87). CONCLUSIONS: The click test has a high level of interobserver reliability. It is rapid, simple, accurate and able to be taught to medical and nursing staff with appropriate training. It has many potential applications including the prediction of fetal lung maturity in women with premature rupture of membranes, and in term and preterm infants who require the bedside testing of surfactant function.

Amniotic Fluid↗

PubMed1996

Spontaneous cryptosporidiosis in captive white-tailed deer (Odocoileus virginianus).

In August 1994, cryptosporidiosis was diagnosed in a diarrheic fawn from a captive white-tailed deer (Odocoileus virginianus) herd maintained for research purposes at The University of Georgia's Warnell School of Forest Resources in Athens, Georgia (USA). From June through August 1995, 11 captive female white-tailed deer were housed in individual barn stalls where they gave birth to 18 fawns. Feces collected at 2 or 3 day intervals from the 18 neonatal fawns for at least 21 days and from 11 adult females once from 1 to 30 days before fawns were born and on three to 12 occasions after their birth were examined for oocysts of Cryptosporidium spp. Feces from all animals appeared normal throughout the period of examination. Oocysts morphologically indistinguishable from those of Cryptosporidium parvum were detected intermittently in the feces of one adult female from 1 to 25 days after parturition and in the feces of her fawn from 11 to 22 days of age. Oocysts also were detected intermittently in feces from twin fawns from 9 to 20 days of age, but not from their mother. Oocysts from deer were infectious for neonatal mice as determined histologically, and for calves as determined by clinical signs and excretion of oocysts.

Animals↗

PubMed1977

Morphology and the natural history of cribriform adenocarcinoma (adenoid cystic carcinoma).

Forty-three examples of cribriform adenocarcinoma (adenoid cystic carcinoma) of mixed glandular origin are reported. Structural studies emphasise the classical cribriform pattern which indicates the capacity of this neoplasm to behave as both an epithelial and a connective tissue type tumour. In terms of survival, it does not appear to be an malignant as other forms of carcinoma arising in similar anatomical locations. The five-year crude survival rate (56%) compares favourably with that of other carcinomas of the palate and paranasal sinuses. A recurrence rate of the order of 20% may persist up to 10 years after primary treatment, and while this is not inimical to longer survival there is clearly a high morbidity.

Adult↗

PubMed1970