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Biomedical subjects

C P Barnett

Publications and source records attributed to C P Barnett.

10 recordsLinked to original sources
PubMed2002

Mechanisms of gastro-oesophageal reflux in preterm and term infants with reflux disease.

BACKGROUND: Transient lower oesophageal sphincter relaxation (TLOSR) is the predominant mechanism of gastro-oesophageal reflux (GOR) in healthy infants but the mechanisms of GOR in infants with GOR disease (GORD) are poorly understood. AIMS: To measure the occurrence of TLOSR, GOR, and gastric emptying (GE) rate in preterm and term infants with GORD. PATIENTS: Thirty six infants were studied and grouped as normals or GORD based on a routine clinical assessment and confirmation of an assessment of GORD by reflux symptom charts and oesophageal pH monitoring. METHODS: A micromanometric assembly incorporating a micro pH electrode recorded oesophageal motility and pH. GE rate was determined using the (13)C-octanoic acid breath test. RESULTS: TLOSR was the predominant mechanism of GOR, triggering 50-100% of GOR episodes (median 91.5%). Abdominothoracic straining significantly increased the occurrence of GOR in association with TLOSR. In infants with GORD, the number of TLOSRs overall was similar to normals but the proportion of TLOSRs accompanied by acid GOR was significantly higher than in normals (16.5% v 5.7%, respectively; p<0.001). Infants with GORD had a similar GE rate to normals. CONCLUSIONS: In infant GORD, acid reflux associated TLOSRs are abnormally common and likely to be a major contributing factor to the pathophysiology of GORD. Infants with GORD do not have delayed GE.

Analysis of Variance↗
PubMed2001

Effect of cisapride on gastric emptying in premature infants with feed intolerance.

OBJECTIVE: To assess the effect of cisapride on gastric emptying and gastro-oesophageal reflux (GOR) symptoms in preterm infants with feed intolerance. METHODS: Sixteen preterm infants (gestational age 24-35 weeks) with feed intolerance were enrolled in the study. Infants were randomized to receive 7 days of cisapride 0.2 mg/kg four times a day, immediately followed by 7 days of placebo or vice versa. Gastric emptying was measured using the [13C]-octanoic acid breath test prior to study entry and repeated on day 5, 6 or 7 after randomization and 5, 6 or 7 days after crossover. The symptoms of GOR were monitored during the study period using a standardized reflux chart. Weight was recorded daily. RESULTS: There was no change in gastric emptying in infants prescribed cisapride (gastric half-emptying time (t1/2) 31.9 +/- 4.7 vs 34.2 +/- 3.9 min for placebo vs cisapride, respectively; P = 0.65). Infants on cisapride had slower growth and there was no change in reflux symptoms. CONCLUSIONS: The use of cisapride in preterm infants with feed intolerance cannot be recommended.

Breath Tests↗
PubMed2001

Characterization of anorectal pressure and the anorectal inhibitory reflex in healthy preterm and term infants.

OBJECTIVES: To evaluate anorectal motor function in healthy premature and term infants with the use of micromanometric techniques. STUDY DESIGN: Anorectal manometry was performed in 22 healthy neonates (9 female) with a mean postmenstrual age of 32 weeks (range, 30 to 38 weeks) with a micromanometric anorectal assembly (od 2.0 mm). The assembly incorporated a 2-cm-long sleeve sensor for measurement of resting anal sphincter pressures and relaxation, and 4 sideholes recorded anal and rectal pressures. Rectal distension was performed with a latex balloon or direct air insufflation to elicit the anorectal inhibitory reflex (AR). RESULTS: The mean anal sphincter pressure, rectal pressure, and rhythmic wave frequency were 40 mm Hg (range, 7 to 65 mm Hg), 11 mm Hg (range, 1 to 27 mm Hg), and 10/min (range, 8 to 14/min), respectively. A normal AR could be elicited in 21 of the 22 infants studied. CONCLUSION: An anorectal micromanometric sleeve catheter is suitable for use in evaluating anorectal pressures in preterm and term neonates. Insufflation of air without the use of a balloon to elicit the AR is reliable and suitable for use in infants <34 weeks. Premature infants older than 30 weeks' postmenstrual age have normal anorectal pressures and a normal AR.

Anal Canal↗
PubMed2000

Behavior and gastroesophageal reflux in the premature neonate.

BACKGROUND: The belief that behavioral observations assist in the clinical diagnosis of gastroesophageal reflux (GER) disease in premature neonates has not been formally tested. The purpose of this study was to determine whether esophageal acidification was associated with a recognizable pattern of behavioral changes in these infants. METHODS: The behavior of 14 healthy premature infants was recorded by a video camera while esophageal pH was simultaneously monitored. For each of 20 acid GER episodes recorded, a 10-minute video epoch, encompassing the onset of acid GER and lasting at least 4 minutes after the onset of GER, was examined. Two independent observers each scored reflux-associated epochs of "general" infant behavior and behavior previously shown to be indicative of reflux in normal term infants. RESULTS: The occurrence of esophageal acidification due to reflux did not significantly alter scores for general behavior. Infants frequently demonstrated reflux-specific behavior, including discomfort, head retraction, and mouthing; however, none of these behavioral patterns was temporally associated with the occurrence of acid GER. CONCLUSIONS: These data indicate that reflux-specific behavioral criteria, established in older term infants, may be inappropriate as diagnostic criteria for GER in premature neonates and may lead to the unnecessary use of antireflux therapy.

Behavior↗
PubMed1999

Characterization of esophageal body and lower esophageal sphincter motor function in the very premature neonate.

OBJECTIVES: To characterize esophageal body and lower esophageal sphincter (LES) motor function in very premature infants. STUDY DESIGN: Esophageal manometry was performed in 12 very premature infants of 26 to 33 weeks' postmenstrual age (PMA) (body weights of 610-1360 g). Esophageal motor patterns were recorded for 30 minutes with a perfused micromanometric sleeve assembly (outer diameter, 2.0 mm). RESULTS: Esophageal pressure waves triggered by dry swallows were predominantly (84%) peristaltic in propagation sequence. All infants showed tonic LES contraction; the mean resting LES pressure (LESP) for individual infants ranged from 5.0 +/- 4.1 mm Hg to 20.0 +/- 4.8 mm Hg. In all infants the LES relaxed (duration, 5.8 +/- 3.0 seconds; nadir pressure, 1.8 +/- 2.6 mm Hg) in response to pharyngeal swallows. Transient LES relaxations (TLESRs) (duration, 21.7 +/- 8.7 seconds; nadir pressure, 0.1 +/- 1.8 mm Hg) occurred on average 2.6 +/- 1.6 times per study; 86% of these relaxations triggered esophageal body common cavity events known to be associated with gastroesophageal reflux. CONCLUSIONS: Esophageal motor function is well developed in very premature infants. Our data also suggest that TLESR is the predominant mechanism of reflux in these babies.

Esophagogastric Junction↗
PubMed1999

Lower esophageal sphincter position in premature infants cannot be correctly estimated with current formulas.

OBJECTIVES: Strobel's formula (Esophageal length = 5 + 0.252 x Height) is frequently used as a guide for determining the distance from the nares to the lower esophageal sphincter (LES) in term infants. The aim of this study was to examine this relationship in premature infants. STUDY DESIGN: The distance from nares to LES was manometrically determined in 156 premature infants (26-40 weeks' postmenstrual age; body weights of 610-3050 g). The ability of body weight, height (body length), head circumference, and postmenstrual age to predict the manometrically determined LES position was evaluated with linear and non-linear regression analyses. RESULTS: Body weight and body length were the most predictive of distance from nares to LES (r(2) = 0.848 and 0.802, respectively). These relationships were non-linear and, in the case of body length, deviated substantially from Strobel's model. CONCLUSIONS: In premature neonates, a different formula is needed for prediction of the distance between nares and LES than that applied to term infants and children.

Anthropometry↗
PubMed1997

Clinicopathological correlations in postasphyxial organ damage: a donor organ perspective.

OBJECTIVES: 1) To assess pathology in the heart, kidneys, lungs, liver, and intestine in babies dying of postasphyxial hypoxic ischemic encephalopathy (HIE), and their suitability for organ transplantation. 2) To analyze the correlation between in vivo clinical markers of collateral organ damage and autopsy findings. STUDY DESIGN: Retrospective cohort study of 58 infants who died of postasphyxial HIE and had autopsies during 1985 to 1994. Collateral organ damage was evaluated clinically and pathologically, and the results compared. RESULTS: Severe pathological changes were observed in 6% to 62% of the five organs studied; 59% of the four major organs had either minor or no pathology. The sensitivity of the clinical predictors ranged from 69% to 100%, and specificity from 50% to 97%. CONCLUSIONS: The organs of newborns dying of severe HIE may be suitable for use as donor organs; predictions of their suitability were most accurate for liver, kidney, and lungs, and least accurate for the heart.

Asphyxia Neonatorum↗