Pediatr Surg Int (1995) 10:519-522 © Springer-Verlag 1995

Madeleine Montgomery • Bj6rn Frenckner Ulla Freyschuss • Wigher Mortensson

Esophageal atresia Long-term-follow-up of respiratory function, maximal working capacity, and esophageal function

Accepted: 25 January 1995

A b s t r a c t Respiratory complications such as recurrent as- piration, infections, and gastroesophageal reflux are com- mon in children who have been treated for esophageal atresia (EA). Some of these children later present abnormal respiratory function. In this study, we compared two groups of children with repaired EA, each consisting of 9 patients (age 8 -21 years). Group I comprised children who had only had minor respiratory complications before the age of 4 years, whereas group II included children who had had severe respiratory complications such as aspiration and pneumonia that continued after that age. The follow-up included esophagography, spirometry, working capacity, and esophageal pH-monitoring. There was no difference between the two groups concerning results in pH-monitor- ing. Three patients in group II had been treated with antireflux surgery at a younger age. Esophageal function was disturbed, with dysmotility in both groups, but dys- function was more severe in patients in group II. Symptoms of asthma or bronchitis occurred in 7 patients equally distributed between the groups. There was a significant difference in spirometry results: patients in group II showed more obstructive as well as restrictive changes. There was no difference in maximal working capacity between the two groups. Capillary blood gases were normal in both groups, indicating that the spirometric changes were without sig- nificant importance.

K e y w o r d s Esophageal atresia • Respiratory function •

Working capacity

.Madeleine Montgomery (~) • Bj6rn Frenckner Department of Paediatric Surgery, St G6ran's/Karolinska Hospital, S-11281 Stockholm, Sweden

Ulla Freyschuss Department of Clinical Physiology, Huddinge Hospital, S-14186 Huddinge, Sweden

Wigher Mortensson Department of Paediatric Radiology, St G6ran's/Karolinska Hospital, S-11281 Stockholm, Sweden

Introduction

Respiratory complications are common in children who have been treated for esophageal atresia (EA) [2, 5 -7 ] . During the neonatal period aspiration, postoperative com- plications, and ventilator treatment may be etiologic fac- tors; later gastroesophageal reflux (GER) recurrent aspira- tion, and recurrent respiratory infections (RTI) occur in these patients, some of whom may later present abnormal lung function [1, 6, 8]. It is not entirely clear what the risk factors are and what role GER plays. Some authors have stated that incompetence of the lower esophageal sphincter (LES) with GER is a significant risk factor [13, 16]. Others have found that children with repaired EA who have suffered from attacks of pneumonia before the age of 4 years later show mild lung damage [6], and emphasize the importance of early lung damage as a cause of later lung function abnormalities.

The aim of this study was to evaluate the long-term results in patients treated for EA with regard to respiratory function, esophageal function, and occurrence of GER, to study the relationship between occurrence of severe respi- ratory complications in early life and subsequent reduced lung function, and to examine the maximal working capac- ity (MWC) and alveolar gas exchange during strenuous physical exercise.

Materials and methods

During the years 1971-1984, 89 patients were treated for EA at St G6ran's Children's Hospital and Karolinska Hospital in Stockholm. The overall survival was 91%. The clinical material has recently been described in detail [10]. All patients treated with an esophageal anastomosis and still living in the Stockholm area were included in the study. Tbxee patients with other severe malformations or diseases were excluded, as were another 3 with esophageal replacements. Altogether, 20 patients were asked to participate in the study, of whom 18 agreed (12 boys and 6 gifts). The median age was 14 years (range 8-21 years), the median gestational age 40 weeks (range 32-42). Two patients were born prematurely (week 32). The

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study was performed with the approval of the Ethics Committee of the hospital. Informed consent was obtained from patients and parents.

The medical records were reviewed focusing on previous respira- tory complications and symptoms of reflux; patients were divided into two groups. All had had respiratory complications such as recurrent RTIs during the first years of life. Group I comprised 9 children who had only had mild symptoms of RTI that did not persist after the age of 4 years. Group II included 9 patients who had had more severe symptoms (obstructive bronchitis, pneumonia, or aspiration) that continued after that age. The time of postoperative ventilator ta'eatment was short in both groups (median < 1 day). Only 1 patient (one in group 2 who was premature) had had long-term ventilator treatment (38 days). The patients answered a questionnaire concerning their present health, previous or present symptoms of respiratory or swal- lowing difficulties, and subjective physical capacity. Their weight and height were measured.

Radiologic examination of the esophagus included fluoroscopic evaluation of morphology and motility. The degree of stricture of the anastomosis was estimated as grade 0 to 3 (grade 3 representing the most severe). Evaluation of esophageal function was based upon the presence of peristaltic activity, segmental or diffuse spasm, dilatation of the upper or lower esophageal segment, delayed emptying, remnants of contrast material in the proximal esophagus, and the risk of spillover. The different variables were given arbitrary scores related to severity and a total score was calculated for each patient to represent the esophageal function.

Total lung capacity (TLC), vital capacity (VC), functional residual capacity (FRC), and residual volume (RV) were determined by the helium dilution method using a closed spirometer system (Jaeger). Ventilatory capacity expressed as forced expiratory volume in 1.0 s (FEV 1.0) was measured by a pneumotachograph (AS 600, Minato). Values were compared to control data from normal Swedish children and adolescents [3, 12, 14]. The patients performed an exercise test to measure the MWC on an electrodynamically braked bicycle ergometer (Siemens-Elema, Sweden) starting with 1.0 W/kg body weight with a stepwise increase (0.5 W) of loads until exhaustion. Each load was maintained for 4 min. The heart rate was obtained by continuous electrocardiographic (6 precordial electrodes) monitoring. Capillary blood gases (pO2, pCO2, pH, base excess) were analyzed in blood samples obtained by finger-prick at rest and immediately after ex- ercise.

Esophageal manometry was performed using a permanently per- fused (0.5 ml/min) trilumen catheter to study motility and determine the position of the LES. pH-monitoring was performed using an ambulatory system (Synectics AB, Stockholm). A monocrystant anti- mony pH-electrode connected to a portable unit was used. The electrode was placed 5 cm above the cardia, which was previously located by manometry. Registration was performed during 24 h. Reflux was defined as a drop of pH below 4 [17]. The registered parameters were: number of reflux episodes, number of episodes longer than 5 min, longest reflux episode, and total time in percent with pH below 4, the so-called reflux index (RI).

The Wilcoxon-Mann-Whitney test and Fisher's exact test were used for statistical analysis. P < 0.05 was considered significant.

Results

Weight and height were within normal limits in all patients (within mean + / - 2 SD of normal Swedish children) [4], with no differences between the two groups. One-half of the patients had some degree of swallowing difficulties (Table 1). Symptoms of reflux such as heartburn or sub- sternal pain also occurred in one-half of the patients (Table 1). There was no difference between groups in the occurrence of these symptoms. Seven patients had asthma or bronchitis (3 in group I, 4 in group II); asthma and allergy occurred in 2 of these. Two patients were receiving

Table 1 Current symptoms in 18 patients with repaired esophageal atresia (ages 8-12 years)

Never Occasionally Often

Swallowing difficulty 9 7 2

Heartburn, regurgitation 9 9

Asthma or bronchitis 11 5 2

Recurrent respiratory 15 3 infections

Table 2 Results of barium esophagography in 15 patients with repaired esophageal atresia

Group 1 Group 2 Total (n = 9) (n = 6)

Dysmotility Mild 5 3 Moderate 4 Severe 3

Degree of stricture in anastomosis

0 (no stricture) 6 2 I (O > 16 ram) 1 3

II (O 8-16 mm) 1 1 III(O <Smm) 1

Total function score Median 7 (2-13)

Median 12.5 (6-15)

continuous medical treatment for their asthma, while the rest had intermittent treatment. Recurrent RTIs had been common earlier in most patients, but at follow-up only 3 had recurrent infections or pneumonias. Two of the patients were smokers (1 in each group). Most patients estimated their own physical capacity to be good. However, there was a difference between the two groups: in group 1 all but 1 patient (8/9) said they had as good a physical capacity as their friends of the same age, while in group 2 the figure was only 4/9 patients. The rest considered their physical fitness to be slightly reduced.

Barium esophagography was performed in 15 patients. It showed dysmotility or aperistalsis in all cases (Table 2), but only one-half of the patients experienced swallowing diffi- culties (Table 1). The degree of stricture at site of the anastomosis is shown in Table 2. One patient, a 21-year-old girl, had a severe anastomotic stricture (7 mm); she had significant swallowing problems. Seven children in group 1 and all in group 2 had various degrees of dilation of the proximal esophageal segment. Retention of contrast mate- rial in the upper segment occurred in most children in group 1 and all in group 2. The amount of remnants was significantly larger in group 2. The total scores of esoph- ageal function are shown in Table 2.

pH-monitoring was performed in 13 of the 18 patients. It showed reflux (RI > 5%) in 3 (2 in group 1, 1 in group 2); the rest had normal results. There was no significant difference between the two groups in the registered para- meters (Table 3); esophageal manometry showed disturbed motility in all cases. Three of the patients in group 2 had

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160

140

I _ _ - . I

120

lOO

% of predicted 80 value

60

20

Fig. 1 Results of spirometry in 18 patients with repaired esophageal atresia, % of predicted value for age group (medians, 75th percentile; RV residual volume, FRC functional residual capacity, VC vital capacity, TLC total lung capacity, FEVI.O forced expiratory volume a t l s )

had an antireflux operation at 3 - 5 years of age; none of the patients in group 1 had been operated upon for reflux.

In group 1 one-half of the patients (4/9) had normal spirometry results. One patient in group 1 had signs of obstructive airway disease, whereas 4 had slight restriction. In group 2 all patients but 1 (8/9) had abnormal results. Seven patients in group 2 had a decreased FEV 1.0, indicating obstructive airway disease, whereas 6 had signs of restrictive disease. Figure 1 shows the spirometry results expressed in percent of predicted value for age group [14, 17] in the two groups. There was a significant difference between the groups with regard to FEV 1.0, RV, and the ratio RV/TLC.

The MWC was estimated as normal in 8/17 patients (within 2 SD ) [11]. The median maximal load was 2.5 W/ kg body weight (range 1.7-4.1 W/kg). The median value for boys was 2.6 W/kg (1.9-4.1) , for girls 2.3 W/kg (1.7-2.7) . There was no significant difference between groups 1 and 2 (Table 4). Capillary blood gases immedi- ately after maximal exercise were within normal ranges in all patients. Resting capillary gases, due to the sampling site, are less reliable and will thus not be commented upon. There was an increase in p02 after work in both groups, which was significantly higher in group 1 than group 2 (Table 4).

Discussion

In accordance with previous studies [1, 6, 8] this study showed that spirometric abnormalities were common in patients who had been treated for EA. More than one-half of our patients showed signs of obstructive as well as restrictive airway disease. The effects of such volume/ flow disturbances on alveolar gas exchange in connection with maximal exercise performance have to our knowledge not been investigated previously. A respiratory restriction of exercise capacity would have important bearings on social life, choice of profession, and even lifetime prog-

nosis. The MWC was decreased in some patients compared to normal Swedish children [11]. The ordinary increase in capillary p02 after maximal work indicated that the spiro- metric changes were without significant importance on gas exchange at a high ventilatory load.

To evaluate the importance of respiratory complications early in childhood, the patients had been divided into two groups. It was primarily the group who had had respiratory complications in early childhood who later showed respi- ratory malfunction. There was a significant decrease in FEV 1.0 and an increase in RV in this group of patients. This obstructive pattern of spirometric data did not seem to affect the working capacity: the patients in group 2 who had had respiratory complications had the same physical work- ing capacity as the other group. Capillary blood gases were normal in both groups. The less marked increase in capil- lary p02 in group 2, although within normal limits, is an observation that might indicate less optimal oxygen trans- port and less efficient diffusion capacity due to distribution of inhaled gas.

Neonatal ventilator treatment may cause later obstruc- tive airway disease [15]. The majority of the patients in this study had only had a short period of postoperative venti- lator treatment. This treatment alone cannot explain the respiratory dysfunction that was seen in patients in group 2.

Table 3 Results of 24-h pH-monitoring in 13 patients with repaired esophageal atresia: medians (ranges) in each group

Group 1 (n = 8) Group 2 (n = 5)

Number of reflux episodes 33.5 (5-53) 33 (10-41)

Reflux episodes > 5 min 0 (0-10) 1 (0-7)

Longest reflux episode 3.5 (1-144) 7 (3-46) (rain)

Reflux index 2.4% (0.5-27.6%) 2.2% (1.5-11.1%)

Table 4 Maximal working capacity, capillary blood gases at rest and immediately after maximal work, medians (ranges) in each group

Group 1 (n = 9) Group 2 (n = 9)

76% (61-108) 71% (56-89) Maximal working capacity (% of expected value for age and sex)

Maximal heart rate

P02 at rest (kPa)

P02 after work (kPa)

PC0a at rest (kPa)

PC02 after work (kPa)

Base excess at rest (mmogl)

Base excess after work (mmol/1)

186 (160-205) 174 (165a-197)

9.8 (8.4-11.3) 9.0 (7.7-12)

13.0 (11.9-16.7) 11.3 (10.8-12.9)

5.1 (4.9-5.6) 5.5 (4.6-6.1)

4.4 (3.9-5.0) 5.0 (4.4-6.0)

-1,0 (-1.7-0) 0.1 (-1.6-1)

-8 (-13.8--2) -4.8 (-7.2--1)

a This patient developed more marked airway obstruction during exercise

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This study showed no relationship between the presence of GER at the follow-up examination and decreased pul- monary function. However, esophageal pH-monitoring was performed in only 13 of 18 patients (8/9 patients in group 1, 5/9 in group 2). The incidence of reflux may be higher at a younger age; in a previous study [9] we found reflux in 50% of patients with repaired EA before the age of 1 year. In this study, 3 of the patients in group 2 had undergone antireflux surgery, but none in group 1 had been operated upon for reflux. This suggested that reflux earlier in life might have been contributing to the reduced respiratory function of these patients.

Some previous studies have indicated a relationship between GER and abnormal pulmonary function [13, 16]; others have found no such relationship [6]. Disturbed motility of the esophagus with recurrent aspiration could be a more important factor. We found that patients in group 2 with respiratory complications had more severe esophageal dysfunction with more retention of contrast material in the dilated upper esophagus, which might constitute a risk of aspiration and subsequent respiratory dysfunction.

In summary, many of the patients were symptom-free or had only minor complaints. However, there was consider- able morbidity in terms of asthma and obstructive bron- chitis. Dysphagia was common but was usually a minor problem, although all patients who had undergone fluoro- scopy and manometry showed disturbed motility. Mild symptoms of GER occurred occasionally in one-half of the patients, but most showed normal pH-monitoring re- sults. There was no relationship between the present occur- rence of reflux and pulmonary dysfunction. Patients with aspiration and other respiratory complications early in life showed decreased respiratory function. The physical work- ing capacity did not seem to be affected.

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