Gastric emptying and gastro-oesophageal reflux in preterm infants.

Gastro-oesophageal reflux is common in preterm infants, but the role of gastric emptying as a causal factor has not been studied before. Gastric emptying was therefore measured in 19 healthy preterm infants (median gestational age 32 weeks) while concurrently measuring 24 hour lower oesophageal pH, using an antimony pH electrode, positioned manometrically. Real time ultrasonic images of the gastric antrum were obtained, and measurements of antral cross-sectional area (ACSA) were made immediately before a nasogastric feed and then during subsequent gastric emptying until ACSA returned to its pre-feed value. Half emptying time (50% delta ACSA) was calculated as the time taken for the ACSA to fall to half the maximal postprandial increment. Mean (SEM) reflux index for the group was 11.9 (2.0)%; number of reflux episodes per 24 hours: 15.4 (1.7); and number of reflux episodes longer than five minutes 5.5 (0.8). Average half emptying times for an individual infant were: median (range) 46 (18-105) minutes. There was no association between gastric emptying rates and any of the indices of gastro-oesophageal reflux, either during the entire 24 hour period for which the lower oesophageal pH was recorded, or in the postprandial periods after the feeds which were studied ultrasonically. Gastro-oesophageal reflux was also unrelated to feed volume and feed type. Asymptomatic gastro-oesophageal reflux is common in preterm infants, but gastric emptying time is not a determinant of it. Inappropriate relaxation of the lower oesophageal sphincter or abnormal oesophageal motility offer more plausible explanations.     

Dual pH probe monitoring versus single pH probe monitoring in infants on milk feeds: the impact on diagnosis.

OBJECTIVES: Oesophageal pH monitoring is the gold standard technique for the detection of gastro-oesophageal reflux in adults and children. A standard parameter used to define "abnormal" reflux is the percentage of recording time for which the gastric pH is < 4. This study investigated the relevance of this measure in infants on regular milk feeds whose gastric contents and refluxate will be neutral for most of the recording time. METHODS: Simultaneous oesophageal and gastric pH monitoring was carried out on all infants who were milk fed exclusively and admitted to hospital for suspected gastro-oesophageal reflux. In vitro studies were performed to establish the buffering capacities of the fruit juice, Dioralyte (a glucose electrolyte solution), breast milk, and milk formula feeds available on the paediatric wards. RESULTS: Complete sets of data were obtained from 30 babies with a mean age of 4 months. Gastric pH was 4 increased this value to 17.81 (2. 46)%. Using a cut off point of 10%, 11 of the 30 babies would have been diagnosed positive for reflux using the conventional method; however, recalculation by ignoring the time for which gastric pH was high doubled this to 22 positive for reflux. CONCLUSION: Combined oesophageal and gastric pH monitoring greatly increases the number of positive results from tests in infants on regular milk feeds.     

Simultaneous monitoring of gastric and oesophageal pH reveals limitations of conventional oesophageal pH monitoring in milk fed infants.

BACKGROUND: Monitoring oesophageal pH conventionally detects "acid reflux" (pH less than 4). The pH of the gastric contents determines whether or not reflux can be detected. AIM: To monitor gastric and oesophageal pH simultaneously in order to determine the effect of milk feeds on gastric pH and how this would influence interpretation of the oesophageal pH record. METHODS: Milk fed infants for whom oesophageal pH monitoring was requested underwent simultaneous gastric and oesophageal pH monitoring using a dual channel pH probe. RESULTS: Twenty of 24 records were technically satisfactory. Mean reflux index was 1.0%, range 0.0-4.0%. Gastric pH was less than 4 for 24.5% (range 0.6-69.1%) of the total time. The average time the gastric pH was greater than 4 after feeds was 130 minutes (range 29-212 minutes). The corrected reflux index (limited to the time the gastric pH was less than 4) was 2.6% (range 0.0-11.0%). CONCLUSION: The pH of the gastric contents may be greater than 4 for prolonged intervals, during which oesophageal pH monitoring using current criteria cannot detect reflux nor correlate it with clinical events. A low reflux index may reflect prolonged buffering of gastric acidity rather than the absence of reflux.     

Gastro-oesophageal reflux—Pathogenesis and clinical implications

Gastro-oesophageal reflux is a common phenomenon in young infants. Normally it will disappear during the first months of life. The most important antireflux mechanism is the lower oesophageal sphincter (LOS). Another main factor to prevent reflux is an adequate oesophageal clearance. The significance of the upper oesophageal sphincter (UOS) and gastric emptying as antireflux barriers has yet to be clarified. Primary or secondary impairment of physiological antiriflux factors may lead to a considerable number of clinical complications.Abbreviations GOR gastro-oesophageal reflux - LOS lower oesophageal sphincter - LOSP lower oesophageal sphincter pressure - UOS upper oesophageal sphincter     

Oesophageal pH monitoring and reflux oesophagitis in irritable infants

Acid reflux and/or oesophagitis may be responsible for inconsolable crying in infants. We evaluated prospectively the presence of acid reflux disease, oesophagitis and the accuracy of pH monitoring in the prediction of oesophagitis in a population of irritable infants. A 24-h oesophageal pH monitoring with a glass electrode and an upper gastro-intestinal tract endoscopy with grasp biopsies were performed in 60 irritable infants, aged 1 to 6 months, not responding to cows milk elimination. The 24-h oesophageal pH monitoring was considered abnormal in 40/60 (66%) babies and histological oesophagitis was present in 26/60 (43%). In the infants with histological oesophagitis, the reflux index (% of the investigation time with a pH <4.0) was >5% in 18/26 (69%). Histology of the oesophagus was normal in 22 of the 40 (55%) infants with an abnormal pH monitoring. The mean reflux index in the group with oesophagitis (12.20%) was significantly higher than in the group with normal histology (8.74) ( P =0.036), although there was an important overlap. The sensitivity and specificity to predict oesophagitis with a reflux index of 5.0% or more was 69.2 and 35.3, respectively. There was not a reflux index which could be related to a clinically useful sensitivity and specificity to predict oesophagitis. Conclusion:acid gastro-oesophageal reflux disease and/or histological oesophagitis were diagnosed in 66% and 43% of irritable infants, respectively. There was no relation between symptoms and abnormal pH metry or oesophagitis; however, the reflux index does not accurately predict oesophagitis and normal histology does not accurately exclude acid gastro-oesophageal reflux disease. Oesophageal pH monitoring and endoscopy provide additional information.Abbreviations GOR gastro-oesophageal reflux - RI reflux index     

Simultaneous monitoring of gastric and oesophageal pH reveals limitations of conventional oesophageal pH monitoring in milk fed infants

BACKGROUND—Monitoring oesophageal pH conventionally detects "acid reflux" (pH less than 4). The pH of the gastric contents determines whether or not reflux can be detected.AIM—To monitor gastric and oesophageal pH simultaneously in order to determine the effect of milk feeds on gastric pH and how this would influence interpretation of the oesophageal pH record.METHODS—Milk fed infants for whom oesophageal pH monitoring was requested underwent simultaneous gastric and oesophageal pH monitoring using a dual channel pH probe.RESULTS—Twenty of 24 records were technically satisfactory. Mean reflux index was 1.0%, range 0.0-4.0%. Gastric pH was less than 4for 24.5% (range 0.6-69.1%) of the total time. The average time the gastric pH was greater than 4 after feeds was 130 minutes (range 29-212 minutes). The corrected reflux index (limited to the time the gastric pH was less than 4) was 2.6% (range 0.0-11.0%).CONCLUSION—The pH of the gastric contents may be greater than 4 for prolonged intervals, during which oesophageal pH monitoring using current criteria cannot detect reflux nor correlate it with clinical events. A low reflux index may reflect prolonged buffering of gastric acidity rather than the absence of reflux.     

Clinical and pH-metric characteristics of gastro-oesophageal reflux secondary to cows' milk protein allergy.

AIMS: The primary aim was to assess whether there were differences in symptoms, laboratory data, and oesophageal pH-metry between infants with primary gastro-oesophageal reflux and those with reflux secondary to cows'' milk protein allergy (CMPA). PATIENTS AND METHODS: 96 infants (mean(SD) age 7.8(2.0) months) with either primary gastro-oesophageal reflux, reflux with CMPA, CMPA only, or none of these (controls) were studied. Symptoms, immunochemical data, and oesophageal pH were compared between the four groups and the effect of a cows'' milk protein-free diet on the severity of symptoms was also assessed. RESULTS: 14 out of 47(30%) infants with gastro-oesophageal reflux had CMPA. These infants had similar symptoms to those with primary gastro-oesophageal reflux but higher concentrations of total IgE and circulating eosinophils (p < 0.005) and IgG anti-beta lactoglobulin (p < 0.003). A progressive constant reduction in oesophageal pH at the end of a feed, which continued up to the next feed, was seen in 12 out of 14 patients with gastro-oesophageal reflux secondary to CMPA and in 24 of 25 infants with CMPA only. No infants with primary gastro-oesophageal reflux and none of the controls had this pattern. A cows'' milk protein-free diet was associated with a significant improvement in symptoms only in infants with gastro-oesophageal reflux with CMPA. CONCLUSION: A characteristic oesophageal pH pattern is useful in distinguishing infants with gastro-oesophageal reflux associated with CMPA.     

Clinical and pH-metric characteristics of gastro-oesophageal reflux secondary to cows' milk protein allergy

AIMS: The primary aim was to assess whether there were differences in symptoms, laboratory data, and oesophageal pH-metry between infants with primary gastro-oesophageal reflux and those with reflux secondary to cows' milk protein allergy (CMPA). PATIENTS AND METHODS: 96 infants (mean(SD) age 7.8(2.0) months) with either primary gastro-oesophageal reflux, reflux with CMPA, CMPA only, or none of these (controls) were studied. Symptoms, immunochemical data, and oesophageal pH were compared between the four groups and the effect of a cows' milk protein-free diet on the severity of symptoms was also assessed. RESULTS: 14 out of 47(30%) infants with gastro-oesophageal reflux had CMPA. These infants had similar symptoms to those with primary gastro-oesophageal reflux but higher concentrations of total IgE and circulating eosinophils (p < 0.005) and IgG anti-beta lactoglobulin (p < 0.003). A progressive constant reduction in oesophageal pH at the end of a feed, which continued up to the next feed, was seen in 12 out of 14 patients with gastro-oesophageal reflux secondary to CMPA and in 24 of 25 infants with CMPA only. No infants with primary gastro-oesophageal reflux and none of the controls had this pattern. A cows' milk protein-free diet was associated with a significant improvement in symptoms only in infants with gastro-oesophageal reflux with CMPA. CONCLUSION: A characteristic oesophageal pH pattern is useful in distinguishing infants with gastro-oesophageal reflux associated with CMPA.     

Dual pH probe monitoring versus single pH probe monitoring in infants on milk feeds: the impact on diagnosis

OBJECTIVES—Oesophageal pH monitoring is the gold standard technique for the detection of gastro-oesophageal reflux in adults and children. A standard parameter used to define "abnormal" reflux is the percentage of recording time for which the gastric pH is < 4. This study investigated the relevance of this measure in infants on regular milk feeds whose gastric contents and refluxate will be neutral for most of the recording time.
METHODS—Simultaneous oesophageal and gastric pH monitoring was carried out on all infants who were milk fed exclusively and admitted to hospital for suspected gastro-oesophageal reflux. In vitro studies were performed to establish the buffering capacities of the fruit juice, Dioralyte (a glucose electrolyte solution), breast milk, and milk formula feeds available on the paediatric wards.
RESULTS—Complete sets of data were obtained from 30 babies with a mean age of 4 months. Gastric pH was ⩽ 4 for a mean (SEM) of 42.4(4.9)% of the recording time. The mean (SEM) percentage time that oesophageal pH was < 4 for the total recording period was 6.89(0.92)%. Recalculation of the percentage of time that the gastric pH was > 4 increased this value to 17.81 (2.46)%. Using a cut off point of 10%, 11 of the 30 babies would have been diagnosed positive for reflux using the conventional method; however, recalculation by ignoring the time for which gastric pH was high doubled this to 22 positive for reflux.
CONCLUSION—Combined oesophageal and gastric pH monitoring greatly increases the number of positive results from tests in infants on regular milk feeds.
     

Sleep phase and gastro-oesophageal reflux in infants at possible risk of SIDS.

The association between gastro-oesophageal reflux and sleep state in 24 infants with confirmed or suspected gastro-oesophageal reflux was studied by monitoring both the pH in the lower oesophagus and polygraphic tracings made during sleep at night. Gastro-oesophageal reflux during the night was confirmed in 20 infants. Three hundred and sixteen precipitous drops of more than one unit of pH were recorded during the studies, 186 during periods of wakefulness. Of 130 drops in pH during sleep, 62 (48%) began during active sleep and 62 during indeterminate sleep. Of the latter, 56 (90%) were associated with brief gross body movements. Only five of the drops in pH (4%) began during quiet sleep. Gastro-oesophageal reflux stopped during active sleep on 56 occasions (43%), in indeterminate sleep in 62 (47%), and in quiet sleep in 12 (9%). Episodes of gastro-oesophageal reflux starting or ending in quiet sleep were uncommon. The occurrence of gastro-oesophageal reflux during active sleep may partly explain why reflux during sleep is a risk factor for pulmonary disease.     

Gastro-oesophageal reflux in infants

Forty bottle-fed babies, 4–12 weeks old, with clinical gastro-oesophageal reflux were studied. Continuous 24 h oesophageal pH monitoring in a prone position demonstrated a gastro-oesophageal reflux with all of the following parameters: reflux index, duration of the longest reflux episode, number of reflux episodes in 24 h, number of reflux episodes >5 min in 24 h. Positional therapy (prone-antitrendelenburg position), applied to all infants, resulted in a normalization of these parameters in ten of them. The remaining 30 infants were treated with milk-thickening agents, as recommended by Carre. Nearly all (N=25) showed an important clinical improvement. A third pH monitoring was performed after 10–14 days of treatment. In six infants the results were completely within normal ranges. In 24 infants a decrease in the number of reflux episodes was demonstrated, with a comparable reflux index and number of long lasting reflux episodes. The duration of the longest reflux episode however increased significantly (P<0.001). Drugs (domperidone, Gaviscon) added to the milk-thickening agents in these 24 children, led to normalization of pH tracings. Clinical symptoms were less severe or disappeared in all infants but one. We conclude that if positional therapy (prone-antitrendelenburg) does not correct gastro-oesophageal reflux in infants, pharmacological treatment should be applied. Milk-thickening agents alone can be effective in individual cases but should be prescribed with care as they can lead to more occult gastro-oesophageal reflux with episodes of longer duration, increasing the risk of oesophagitis or respiratory distress.Abbreviation GOR gastro-oesophageal reflux     

Oral ranitidine and duration of gastric pH >4.0 in infants with persisting reflux symptoms

BACKGROUND: Ranitidine is a drug commonly used in pathological gastro-oesophageal reflux (GOR) in infants. Non-responsiveness has been reported. Data regarding the effect of ranitidine on oesophageal acid exposure and reduction of gastric acid secretion are limited in this age group. OBJECTIVE: To evaluate oesophageal acid exposure, reduction of gastric acid secretion and histology of oesophageal biopsies in infants who clinically do not respond to oral ranitidine. PATIENTS AND DESIGN: 103 infants (mean age 3.3 +/- 1.8 mo) with persisting symptoms of reflux despite administration of ranitidine, prescribed previously by a referring physician, at a mean (SD) dose of 9.4 (+/- 3.3) mg/kg/d for at least 2 wk (mean 30 d), were submitted to a 24-h pH study and oesophageal biopsy (90/103 patients). RESULTS: Histological oesophagitis was present in 21/90 (23%). The oesophageal reflux index (RI) was >5% and >10% in 21/103 (20%) and 6/103 (6%) infants, respectively. Gastric pH was >4.0 during <50%, >50%, >75% and >90% of the duration of pH monitoring in 33/103 (32%), 70/103 (68%), 22/103 (21%) and 7/103 (7%), respectively. By simple regression analysis, the dosage of ranitidine correlated with the oesophageal RI (r = 0.21; p = 0.05), but not with the duration of time gastric pH was >4.0 (r = 0.09; p = 0.39). Histological oesophagitis did not correlate with ranitidine dosage, duration of treatment, duration gastric pH was >4.0 and oesophageal reflux index. CONCLUSION: Some infants presenting with symptoms assumed to be GOR and acid related fail to respond to acid suppression with ranitidine, either because they need better acid suppression or because the symptoms are not acid related.     

Postural drainage and gastro-oesophageal reflux in infants with cystic fibrosis

Gastro-oesophageal reflux is increased in cystic fibrosis and it is possible that postural drainage techniques may exacerbate reflux, potentially resulting in aspiration and further impairment of pulmonary function. AIM: To evaluate the effects of physiotherapy with head down tilt (standard physiotherapy, SPT) on gastroesophageal reflux and to compare this with physiotherapy without head down tilt (modified physiotherapy, MPT). METHOD: Twenty (mean age 2.1 months) infants with cystic fibrosis underwent 30 hour oesophageal pH monitoring during which SPT and MPT were carried out for two sessions each on consecutive days. RESULTS: The number of reflux episodes per hour, but not their duration, was significantly increased during SPT compared with MPT (SPT 2.5 (0.4) v MPT 1.6 (0.3), p = 0.007) and to background (1.1 (0.)1, p = 0.0005). Fractional reflux time was also increased during SPT (11.7 (2.6)%) compared with background (6.9 (1.3)%) p = 0.03) but not compared with MPT (10.7 (2.7)%). There was no significant difference between MPT and background for number of reflux episodes, their duration, or fractional reflux time. CONCLUSIONS: SPT, but not MPT, was associated with a significant increase in gastro-oesophageal reflux in infants with cystic fibrosis.     

Fundoplication in preterm infants with gastro-oesophageal reflux

Gastro-oesophageal reflux in preterm infants may result in recurrent pulmonary insult due to aspiration of gastric contents, and intractable obstructive apnoea. Fundoplication is effective in controlling reflux when medical management has failed. Our experience between 1981 and 1990 was reviewed to assess the efficacy of early surgery in the management of 11 such infants. The infants had a median gestational age of 29 weeks and a median birthweight of 1032 g. Nine infants had fundoplication for recurrent aspiration pneumonitis and two for intractable apnoea. The median age at the time of surgery was 100 days and the median weight of the infants was 2640 g. Nine infants were oxygen dependent and two were still ventilated at the time of surgery. The operative procedure was well tolerated by 10 of the 11 infants. Surgery failed to control reflux in two infants, although good control was obtained in the one who had subsequent surgery. Three infants required prolonged ventilation postoperatively; two of them died later from pulmonary failure. The median time to discharge was 24 days (8-113 days). All infants with intractable apnoea were cured by surgery. Fundoplication is an effective method of management when used early in the treatment of chronic gastro-oesophageal reflux in preterm infants. There is minimal morbidity from the surgical procedure.     

Prone and left lateral positioning reduce gastro-oesophageal reflux in preterm infants.

AIM: To examine the effect of body position on clinically significant gastro-oesophageal reflux (GOR) in preterm infants. METHODS: Eighteen preterm infants with clinically significant GOR were studied prospectively using 24 hour lower oesophageal pH monitoring. Infants were nursed in three positions (prone, left, and right lateral) for 8 hours in each position, with the order randomly assigned. Data were analysed using analysis of covariance. RESULTS: The median (range) reflux index (RI) for the group was 13.8% (5.8-40. 4). There was no significant difference in the mean time spent in each position. RI (mean % (SEM)) was significantly less in prone (6. 3 (1.7)) and left lateral positions (11.0 (2.2)), when compared with the right lateral position (29.4 (3.2)); p<0.001. The mean (SEM) longest episodes (mins) of GOR were reduced by prone and left positions (8.6 (2.2) and 10.0 (2.4), respectively) compared with the right position (26.0 (3.9)); p<0.001. The mean (SE) number of episodes was reduced by prone (15.4 (2.8)) and left (24.6 (3.5)) positions when compared with right (41.6 (4.6)) (p<0.001). CONCLUSIONS: Prone and left lateral positions significantly reduce the severity of GOR, by reducing the number of episodes and the duration of the longest episodes. Such positioning offers a useful adjunct to the treatment in hospital of preterm infants with gastro-oesophageal reflux.     

Management of gastro-oesophageal reflux.

Parental reassurance and thickened feeds are the only requirements in the management of infants with reflux when this is the sole detectable gastro-oesophageal abnormality. In view of the strong propensity for spontaneous clinical resolution and the excellent results achieved by conservative management, infants with reflux due to a partial thoracic stomach (hiatal hernia) uncomplicated by a stricture should be treated in the first instance by postural therapy, with or without thickened feeds and supplements of antacids, domperidone, and cimetidine. Those showing no response after an adequate period of conservative treatment should have an antireflux operation. The Belsey MK IV type of fundoplication is preferred. Only an exceptional patient will require to be treated surgically before 12 months of age. The same surgical antireflux procedure, combined with oesophageal dilatations as necessary, is the treatment of choice for patients with a partial thoracic stomach complicated by a reflux oesophageal stricture. A similar treatment regimen should be followed for patients with reflux after repair of an oesophageal atresia. Surgical correction is mandatory for all infants with reflux due to a large combined hiatal hernia.     

Postural drainage and gastro-oesophageal reflux in infants with cystic fibrosis

Accepted 8 November 1996
Gastro-oesophageal reflux is increased in cystic fibrosis and it is possible that postural drainage techniques may exacerbate reflux, potentially resulting in aspiration and further impairment of pulmonary function.
AIM—To evaluate the effects of physiotherapy with head down tilt (standard physiotherapy, SPT) on gastro-oesophageal reflux and to compare this with physiotherapy without head down tilt (modified physiotherapy, MPT).
METHOD—Twenty (mean age 2.1 months) infants with cystic fibrosis underwent 30 hour oesophageal pH monitoring during which SPT and MPT were carried out for two sessions each on consecutive days.
RESULTS—The number of reflux episodes per hour, but not their duration, was significantly increased during SPT compared with MPT (SPT 2.5 (0.4) v MPT 1.6 (0.3), p = 0.007) and to background (1.1 (0.)1, p = 0.0005). Fractional reflux time was also increased during SPT (11.7 (2.6)%) compared with background (6.9 (1.3)%, p = 0.03) but not compared with MPT (10.7 (2.7)%). There was no significant difference between MPT and background for number of reflux episodes, their duration, or fractional reflux time.
CONCLUSION—SPT, but not MPT, was associated with a significant increase in gastro-oesophageal reflux in infants with cystic fibrosis.

     

Gastric emptying with gastro-oesophageal reflux.

The time taken for gastric emptying of a liquid (milk) or a semi-liquid (pudding) meal was evaluated in 477 infants and children. These patients were referred for suspected gastro-oesophageal reflux and underwent gastro-oesophageal scintigraphy, prolonged oesophageal pH study, manometric evaluation of the lower oesophageal sphincter pressure, and fibreoptic endoscopy. No difference in gastric emptying was observed in children aged under 3 years, regardless of the presence or absence of the gastro-oesophageal reflux, the pressure of the lower oesophageal sphincter, or the presence of oesophagitis. In children over 6 years, however, gastric emptying was significantly delayed in those presenting with reflux compared with those without reflux; in children over 3 years there was slower gastric emptying in those with a decreased lower oesophageal sphincter pressure compared with those with higher pressure and in those with overt oesophagitis compared with those without oesophagitis. This study suggests that gastro-oesophageal reflux is more severe in childhood than in infancy, probably due to more complex motor disorders affecting the gastric fundus as well as lower oesophageal sphincter function.     

Effects of formula feeding on gastric acidity time and oesophageal pH monitoring data

Gastro-oesophageal reflux (GOR) occurs mainly during postcibal (PC) periods. The duration of PC gastric acidity and the incidence of GOR were analysed in 11 asymptomatic premature infants. GOR was studied during PC periods of 120 min and also during the following 120 min defined as fasting (FT) periods. These infants were subjected to simultaneous continuous gastric and oesophageal pH monitoring using a double-blind crossover technique. Two formulae with different fat contents (2.6 vs 3.6 g/100 ml) and different carbohydrate concentrations (8.1 vs 7.3 g/100 ml; malto-dextrin 2.8 vs 1.9 g/100 ml) were given. Gastric acidity (pH<4) in the PC periods lasted significantly (P<0.001) longer (68 min±10) with the low fat/high malto-dextrin formula versus 43 min±11 with the high fat/low malto-dextrin formula. Oesophageal pH monitoring data were within normal limits for the total investigation time in all infants. During PC periods acid GOR was detected more frequently in the group with a low fat formula. More PC GOR was recorded when the gastric acidity time was longer.Abbreviations F1 formula 1 - F2 formula 2 - FT fasting - GOR gastro-oesophageal reflux - PC postcibal     

Observations on gastro-oesophageal reflux,central apnoea and heart rate in infants

Respiratory movements and heart rate were monitored continuously during the course of 2 h radionuclide studies to detect gastro-oesophageal reflux (GOR) in 22 infants following a milk feed. Twenty infants had GOR, to upper oesophageal/pharyngeal level in 19, and 17 had central apnoea between 3 and 15s. Prolonged central apnoea (greater than 20s) was not observed. Bradycardia, defined as a heart rate less than 80 beats/min for 10s or more, was observed in only 1 infant who did not have GOR. No correlation was found between the number or duration of reflux episodes and the frequency of respiratory pauses between 3 and 17s. When data from individual infants were examined a possible temporal relation between the occurrence of GOR and central apnoea was seen in only two infants; in each case, detailed examination suggested that apnoea was more closely associated with sleep than with GOR. Although the respiratory monitoring system did not include airflow sensors, the almost complete absence of bradycardia suggested that prolonged obstructive apnoeas did not occur. We conclude that any relation between GOR and central apnoeas less than 15 s is not of a direct cause/effect nature.