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Gastrointestinal distention in infants
G A S T R O I N T E S T I N A L D I S T E N T I O N IN I N F A N T S ALEX GERBER, MAJOR, MC, U S A FORT I~IL:Eu KAN.
H E puzzling behavior of gastroingas has intrigued numerous investigators. Clinicians and laboratory workers have contributed equally to the voluminous literature on the problem of gaseous distention, but m a n y questions remain to be answered. These problems are primarily of interest to the surgeon who must deal with paralytic and mechanical ileus in his everyday practice, but there are additional facets of the problem which are interesting to the pediatrician. The three sources of gastrointestinal gas are: (a) food decomposition, (b) swallowed air, and (c) diffusion from the blood stream (Table I).
T testinal
FOOD DECOMPOSITION
The gaseous product of food decomposition is chiefly C02, especially in the i n f a n t whose food consists largely of carbohydrates. Because of the rapid emptying time of the infant stomach, this gas is formed mainly in the small intestine by the action of fermentative bacteria. As protein and roughage are added to the diet, other gases are formed as shown on Table I. It should be noted that cellulose breaks down in the large bowel due only to bacterial action, since the enzyme cellulase is not present in human beings. 1 Putrifactive bacteria acting on proteins form odoriferous gases. Milk is the p r i m a r y source of protein in newborn infants. B y far,
the largest amount of gas produced by food is CO~ which is readily absorbed by the intestinal tract. Nitrogen is not a product of food decomposition. SWALLOWED AIR
Animal experiments and clinical observations indicate that swallowed air may be considered the chief source of intestinal gas. 2-7 Wangensteen, ~ who with his co-workers has studied the problem extensively, states that 68 per cent of gastrointestinal gas is due to swallowed air. This concept does not fit the observed clinical facts according to Begg, 8 who claims that diffusion of gases from the blood stream is of more importance in distention. Abdominal films of infants normally reveal gas in the small bowel, but this finding in adults is usually abnormal. The explanation of this difference is obscure. In general, pediatricians feel that infants readi]y swallow air, and they admonish parents to " t a k e the bottle away as soon as it is emptied of milk lest the baby suck in a i r . " Bottle nipples, used as pacifiers, are stuffed with cotton for the same reason. Moreover, m a n y pediatricians feel that aerophagia is an important contributory cause of colic in infants2 -12 The explanation is that the h u n g r y or u n d e r f e d infant starts crying and sucks on anything available. Both of these acts allegedly initiate aerophagia and intestinaI distention. 67
68
THE
JOURNAL
OF
The resultant colic causes more crying and establishes a vicious cycle. It has also been contended that infants ingest air with each inspiration irrespective of the crying factor. Lcigh and Belton ~-8 passed a tube into
the infant's stomach and placed the free end under water. They found gas bubbling up through the water with each expiration, and they postulated air ingestion on inspiration due to a negative intragastric pressure.
TABLE GAS
CI~IEF
N~
PEDIATRICS
I
SOURCES
RE~[ARKS
I
(a) (b) (a) (b)
CQ
O~ H~ CH4 (marsh gas) IGS NH~ Indole Skatole
Swahowed air (N 2 ~ 79.02 vol. % ) Inert gas--never the end product Diffusion from blood of food decomposition Diffusion from blood Action of acid gastric contents on carbohydrates present in alkaline pancreatic and intestinal secretions (c) Kction of fermentative bacteria (c) In small intestine- bacillus bifidus, on carbohydrates etc. (d) Decomposition of cellulose (d) In large bowel: ce]lulose --> CO2 + f~;tty acids (a) Swallowed air (O~ ~ 20.94 vol. % ) ( b ) Diffusion from blood Formed only in large bowel by bacterial action since the enzyme From cellulose cellulase is not present in man Action of putrefactive bacteria on proteins
Odoriferous gases; last three are found only in traces
TABLE II
J
X-KAY EVIDENCE 0 F STOMAC~I GAS
2. 3.
12 da. 18 da. 18 da.
FILM 1 FASTING Moderate Moderate Moderate
4. 5. 6.
18 da. 21 da. i me.
7,
3 Ill0.
8. 9. 10.
CASE NO.
AGE
FILM 2 AFTER SUCKING ON EMPTY
~OTTLE
FILM
3 AFTER
DEGLUTITION
AMOUNT INGESTED
(C.C.)
Marked increase Marked increase No change
30 60 30
Minima[ Moderate Minimal
No change No change Minimal change No change No change No change
Marked increase Marked increase Moderate increase
45 30 15
3 me. 4 too. 5 me.
Moderate Minimal Moderate Moderate
No No No No
Marked increase Marked increase Marked increase Slight increase
45 45 30 30
11.
9 me.
Moderate
No change
Moderate increase
240
12.
18 too.
Moderate
No change
Moderate increase
30
13.
6 yr.
Minimal
No change
Marked increase
].
change change change change
]20
~EMAI~KS
I n f a n t burped before third film was taken Fig. 1 Fig. 2 Note air ingested with only 15 e.c. of milk. Fig. 3
I n f a n t burped before third film was taken Infant burped before third film was taken Milk ingested in two minutes Fluid gulped down in eight seconds. Fig. 4
GERBER:
GASTROINTESTINAL DISTENTION IN INFANTS
SoverP 4 found that infants do not swallow air by sucking on an empty bottle or their fingers. He concluded from his clinical experiments and x-ray studies that infants only swallow air during the act of deglutition. These observations obviously are in conflict with the beliefs of a good m a n y pediatricians. To evaluate Soveri's work, roentgenological studies were carried out on patients from the newborn n u r s e r y and the pediatric ward. Thirteen subjeers were chosen ranging in age from 12 days to 6 years. A preliminary scout film of the abdomen was taken following four to eight hours of fasting. The flat film was repeated after t h i r t y minutes of sucking on an empty bottle; the frustrated, younger subjects cried lustily for a p a r t of this time. A third film was taken after an oral intake of 15 to 120 c.c. of milk. The results are tabulated in Table II. Figs. 1 to 4 are representative films. The findings indicate that, contrary to popular opinion, air is not easily swallowed by infants except during deglutition. The fihns i n v a r i a b l y revealed no change in the stomach gas pattern following t h i r t y minutes of sucking on an empty bottle, but the stomach routinely appeared filled with air a f t e r the ingestion of milk. I n a few instances, the infant b u r p e d the air out before the t h i r d film could be taken, and there was minimal demonstrable roentgenographic change. The subject apparently swallowed two to three times as much air as fluid. The stomach of an infant was visualized following the injection of 75 c.c. of air which showed a gas bubble coinp a r i n g in size to the gas shadow formed by ingesting 30 c.c. of milk (Fig. 5).
69
Another investigation conclusively demonstrated that the stomach gas was swallowed air rather than the result of food decomposition or diffusion. Three subjects were allowed to ingest a measured amount of fluid, and at a subsequent time the same amount of fluid was gavaged. Films taken following gavage of fluids did not reveal the characteristic air-filled stomach (Fig. 6). These findings confirm Soveri's investigations. 14 F r o m a theoretical standpoint, it is difficnR to conceive of air entering tile stomach of infants with each inspiration. is I f as little as 0.1 e.e. of air was ingested with each inspiration, an i n f a n t with a respiratory rate of 36 would ingest more t h a n 2,500 c.c. of air in each twenty-four-hour period, exclusive of air swallowed during feeding. Atmospheric air is 80 per cent nitrogen which is poorly absorbed by the intestinal ~ract, and swallowed air is largely passed as flatus25 Adults usually egest between 500 and 1,000 e.e. of flatus per day, and the gastrointestinal tract contains an average of 1,300 e.e. of gas a t any one time. 1~ The concept of continuous, inspiratory air swallowing in infants seems unreasonable in view of these figures. Gastric tubes were passed on three infants in the nursery, and the free ends were placed u n d e r water. In each instance there was an immediate bubbling of gas as the stomach emptied, since the intragastric pressure is a positive 8 to 13 em. of water as is the intraperitoneal pressure.16, 17 There was no f u r t h e r passage of gas through the water with expiration, and thus Leigh and Belton's is findings could not be confirmed.
70
THE
JOURNAL
OF
A.
PEDIATRICS
B.
C.
Fig, 1,--Case
4, I n f a n t a g e d 18 d a y s . on an empty bottle,
A, F a s t i n g film. B, A f t e r s u c k i n g f o r t h i r t y min~l~e~ C, A f t e r i n g e s t i o n o f 45 c,c, o f m i l k ,
GERBER:
GASTROINTESTINAL
A.
Fig. 2.~Case
5, I n f a n t a g e d 21 d a y s . on an empty bottle.
DISTENTION
IN
INFANTS
71
B.
A, F a s t i n g film. B , A f t e r s u c k i n g f o r t h i r t y G, A f t e r i n g e s t i o n o f 30 e,c, o f m i l k .
minutes
72
THE
J O U R N A L OF P E D I A T R I C S
C. F i g . 3 . - - C a s e 6, I n f a n t a g e d 1 m o n t h . on a n e m p t y bottle.
A, F a s t i n g film. B, A f t e r s u c k i n g f o r t h i r t y m i n u t e s G, A f t e r i n g e s t i o n of 15 e.c. of m i l k .
GERBER:
A.
GASTROINTESTINAL DISTENTION IN
INFANTS
73
B.
Fig'. 4 . - - C a s e 13. I n f a n t a g e d 6 y e a r s . A, F a s t i n g film. B, A f t e r s u c k i n g f o r t h i r t y m i n u t e s on a n e m p t y bottle. C, A f t e r i n g e s t i o n of 120 e.c, of w a t e r in a f e w g u l p s .
74
Fig.
THE
5.--Infant
aged
5 months. stomach.
J O U R N A L OF P E D I A T R I C S
A b d o m i n a l film f o l l o w i n g i n j e c t i o n of C o m p a r e w i t h F i g s . l, 2, 3, a n d 4.
75 c.e. of a i r
into
~~ Fi~
6.--Infant
a g e d 21 d a y s .
A~ A f t e r i n g e s t i o n of 30 c.c. of m i l k . c.c. of m i l k .
B, A f t e r g a r a g e of 30
GERBER: DIFFUSION
OF
GASTROINTESTINAL DISTENTION IN GASES
The role of diffusion in the development of distention has been adequately stressed. Diffusion of gases into and out of the gastrointestinal tract unquestionably occurs and apparently does so in a manner conforming to gas laws. Gas under different pressures on two sides of a semipermeable membrane will diffuse until equilibrium is established. That intestinal gases obey this
.4_.
INFANTS
75
Dunn and Thompson is obtained the same results in experiments with human beings. Anderson and Ringsted 7 brilliantly analyzed the problem Of ileus from a theoretical consideration of the gas lairs and by animal experimentation. They eoneluded that intestinal distention is due almost entirely to swallowed air. They also claim that the physical laws prohibit diffusion of gases into
~,
Fig. 7.--Child aged 8 years. A, A c u t e d i l a t a t i o n of s t o m a c h in a n a g i t a t e d child i o r o b a b l y d u e to a s y m p a t h e t i c r e s p o n s e . B , N o r m a l fihn of sa~zle p a t i e n t .
law was Shown by Mclver and associates. 1~ When air (C02 = 0.04 vol. per cent) was introduced into the stomaeh of experimental animals, CO2 diffused into the stomach until the concentration was equal to that of the blood (C02 ~ 5.3 vol. per cent). Conversely, when air with a high percentage of CO~ was introduced, CO2 diffused out of the stomach into the blood until equilibrium was established.
the intestines u n d e r the circumstances that pertain in intestinal distention. How does one explain gastrointestinal distention when swallowed air apparently is no factor ? Wangensteen and Rea 4 produced an intestinal obstruction in a series of dogs by ligation of the distal ileum. A n u m b e r of these animals were then subjected to esophagostomy with inversion of the distal end, thus excluding swallowed
76
THE JOURNAL OF PEDIATRICS
air from the intestinal tract. Two of these animals developed tremendous distention, more marked than any of the controls. The only explanation of this gas is diffusion, since the chief gaseous product of food fermentation is COs which is rapidly absorbed. I t is also difficult to explain acute gastric dilatation on the basis of swallowed air only. Fig. 7, A is an abdominal fihn of a fasting 8-year-old girl who became extremely agitated when told that she was to suck on a nipple bottle for t h i r t y minutes. The gastric dilatation evidently appeared in a matter of seconds. An abdominal film of the same subject, taken on another day when she was calm, is shown for comparison (Fig. 7, B). The sympathetic nervous system, which is predominantly inhibitory to the gastrointestinal tract, apparently played a role in this instance of gastric dilatation. Dragstedt ~9 has discussed the sympathetic and vagal factors in acute dilatation of the stomach. The role of the autonomie nervous system in the production of gastrointestinal distention is worthy of f u r t h e r investigation. Many questions concerning distention of the digestive tract remain unanswered. Despite the evidence that air swallowing takes place chiefly during deglutition, it has been shown that the newborn i n f a n t ' s stomach fills with air as soon as six minutes after birth, and subsequent films reveal the small and large intestine to be filled with gas. 2~ It seems to be conclusively established that the gas in the intestines of newborn infants is swallowed air, because no intestinal gas is found in a newborn infant with an esophageal atresia. No diffusion of gases can take place from the blood stream into the empty intestinal tract in accordance
with the gas laws2, 7 The rapid appearance of intestinal gas in the newborn infant may be a phenomenom peculiar to the first few hours of life. Perhaps the superior esophageal constrictor of the newborn infant is not as efficient a pinchcock as it is later in infancy and allows more air swallowing than one normally expects. The answer to this question must await f u r t h e r studies on the pneumodynamics of the digestive tract. SUM~IARY
Gastrointestinal gas is produced from food decomposition, swallowed air, and diffusion from the blood stream as established in previous studies on the subject. The x-ray investigations presented here were carried out to f u r t h e r evaluate the role of swallowed air in gaseous distention. These studies indicate that air is swa]lowed mainly during deglutition; little, if any, air is ingested while crying or sucking as is popularly believed. The suggestion that i n f a n t s normally ingest air during each inspiration has not been confirmed, although air swallowing unquestionably occurs during the first few minutes of life. F u r t h e r investigation of the behavior of intestinal gases is indicated, particularly the role of the autonomic nervous system in the production of gastrointes~ tinal distention. REFERENCES 1. Johnson, ~I. H.: Bridges Dietetics for the Clinician, Philadelphia, 1949, L e a & Febiger, p. 110. 2. Fine, J., and Levenson, W. S.: Effect of ]~oods on Postoperative Distention, Am. J. Surg. 21: 184, 1933. 3. Itibbard, J., and Wangensteen, 0. I~I.: Character of the Gaseous Distention in Mechanical Obstruction of the Small Intestine, Proc. Soe. Exper. Biol. & Med. 31: 1063, 1934.
GERBER:
GASTROINTESTINAL DISTENTION IN INFANTS
4. Wangensteen, O. H., and t~ea, C. E.: The Distention Factor in Simple Intestinal Obstruction, Surgery 5: 327, ]939. 5. Mclver, M. A., Benedict, E. B., and Cline, J. W , J r . : Postoperative Gaseous Distention of the Intestines, Arch. Surg. 13: 588, 1926. 6. Maddock, W. G., Bell, J. L., and Tremaine~ M. J.: Gastrolntestinal Gas, Ann. Surg. 130: 512, 1949. 7. Anderson, K.~ and ]%iugsted, A.: Clinical and Experimental Investigations on Ilcus With Particular Reference to the Genesis of Intestinal Gas, Aeta chir. scandinav. 80: 475, 1943. 8. Begg, R. C.: A Rational Theory of Intestinal Distention and Its Urological Application, J. Urol. 59: 358, 1948. 9. Grulee, C. G., and Eley, R. C.: The Child in Health and Disease, Baltimore, 1948, Williams & Wilkins Co., p. 89. 10. Jeans, P. C., and Marriott, W . M . : Inf a n t Nutrition, ed. 4, St. Louis, 1947, The C. V. Mosby Co., p. 356. l l . Nelson, W . E . : Textbook of Pediatrics, ed. 5, Philadelphia, ]950, W. B. Saunders Co., p. 147. 12. Anderson, J. A.: B r e n n e m a n n ' s Practice of Pediatrics, Hagerstown, 1948~ W. F: Prior Co., vol. I~ chap. 27, p. 4.
77
13. Leigh, M. C., and Belton, M. K, : Pediatric Anaesthesia, New York, 1953~ Tile Macmillan Co., p. 16. 14. Soveri, V.: Der Verlauf der L u f t dureh den Verdaungskanal des Sauglings, Acta paediat. (supp. 3) 23: 1, 1939. 15. McIver, M. A., Redfield, A. C., and Benedict, E . B . : Gaseous Exchange Be~ tween the Blood and the Lumen of the Stomach aud Intestines, Am. J. Physiol. 76: 92, 1926. 16. Blair~ H. A., Dern, i%. J., and Bates, P. L.: The Measurement of the Volume of Air in the Digestive Tract, Am. J. Physioh 149: 688, 1947. 17. Drye, J.C.: Intraperitoneal Pressure in the I~Iuman~ Surg.~ Gynee. & Obst. 87: 472, 1948. 18. Duun, A. D., and Thompson, W.: The Carbon Dioxide and Oxygen Content of Stomach Gas in Normal Persons, Arch. Int. Med. 31: 1, 1923. 19. I)ragstedt, L. R.: Acute Dilatation of the Stomach, Lewis' Practice of Surgery. I-Iagerstown, 1950, W. F. Prior Co., vol. 6, chap. 10. 20. Paine, J. R., and Nessa, C . B . : Observations on the Distribution and T r a n s p o r t of Gas in the Gastrointestinal Tract of Infants and Young Children, Surgery Ii: 281, 1942.
H E puzzling behavior of gastroingas has intrigued numerous investigators. Clinicians and laboratory workers have contributed equally to the voluminous literature on the problem of gaseous distention, but m a n y questions remain to be answered. These problems are primarily of interest to the surgeon who must deal with paralytic and mechanical ileus in his everyday practice, but there are additional facets of the problem which are interesting to the pediatrician. The three sources of gastrointestinal gas are: (a) food decomposition, (b) swallowed air, and (c) diffusion from the blood stream (Table I).
T testinal
FOOD DECOMPOSITION
The gaseous product of food decomposition is chiefly C02, especially in the i n f a n t whose food consists largely of carbohydrates. Because of the rapid emptying time of the infant stomach, this gas is formed mainly in the small intestine by the action of fermentative bacteria. As protein and roughage are added to the diet, other gases are formed as shown on Table I. It should be noted that cellulose breaks down in the large bowel due only to bacterial action, since the enzyme cellulase is not present in human beings. 1 Putrifactive bacteria acting on proteins form odoriferous gases. Milk is the p r i m a r y source of protein in newborn infants. B y far,
the largest amount of gas produced by food is CO~ which is readily absorbed by the intestinal tract. Nitrogen is not a product of food decomposition. SWALLOWED AIR
Animal experiments and clinical observations indicate that swallowed air may be considered the chief source of intestinal gas. 2-7 Wangensteen, ~ who with his co-workers has studied the problem extensively, states that 68 per cent of gastrointestinal gas is due to swallowed air. This concept does not fit the observed clinical facts according to Begg, 8 who claims that diffusion of gases from the blood stream is of more importance in distention. Abdominal films of infants normally reveal gas in the small bowel, but this finding in adults is usually abnormal. The explanation of this difference is obscure. In general, pediatricians feel that infants readi]y swallow air, and they admonish parents to " t a k e the bottle away as soon as it is emptied of milk lest the baby suck in a i r . " Bottle nipples, used as pacifiers, are stuffed with cotton for the same reason. Moreover, m a n y pediatricians feel that aerophagia is an important contributory cause of colic in infants2 -12 The explanation is that the h u n g r y or u n d e r f e d infant starts crying and sucks on anything available. Both of these acts allegedly initiate aerophagia and intestinaI distention. 67
68
THE
JOURNAL
OF
The resultant colic causes more crying and establishes a vicious cycle. It has also been contended that infants ingest air with each inspiration irrespective of the crying factor. Lcigh and Belton ~-8 passed a tube into
the infant's stomach and placed the free end under water. They found gas bubbling up through the water with each expiration, and they postulated air ingestion on inspiration due to a negative intragastric pressure.
TABLE GAS
CI~IEF
N~
PEDIATRICS
I
SOURCES
RE~[ARKS
I
(a) (b) (a) (b)
CQ
O~ H~ CH4 (marsh gas) IGS NH~ Indole Skatole
Swahowed air (N 2 ~ 79.02 vol. % ) Inert gas--never the end product Diffusion from blood of food decomposition Diffusion from blood Action of acid gastric contents on carbohydrates present in alkaline pancreatic and intestinal secretions (c) Kction of fermentative bacteria (c) In small intestine- bacillus bifidus, on carbohydrates etc. (d) Decomposition of cellulose (d) In large bowel: ce]lulose --> CO2 + f~;tty acids (a) Swallowed air (O~ ~ 20.94 vol. % ) ( b ) Diffusion from blood Formed only in large bowel by bacterial action since the enzyme From cellulose cellulase is not present in man Action of putrefactive bacteria on proteins
Odoriferous gases; last three are found only in traces
TABLE II
J
X-KAY EVIDENCE 0 F STOMAC~I GAS
2. 3.
12 da. 18 da. 18 da.
FILM 1 FASTING Moderate Moderate Moderate
4. 5. 6.
18 da. 21 da. i me.
7,
3 Ill0.
8. 9. 10.
CASE NO.
AGE
FILM 2 AFTER SUCKING ON EMPTY
~OTTLE
FILM
3 AFTER
DEGLUTITION
AMOUNT INGESTED
(C.C.)
Marked increase Marked increase No change
30 60 30
Minima[ Moderate Minimal
No change No change Minimal change No change No change No change
Marked increase Marked increase Moderate increase
45 30 15
3 me. 4 too. 5 me.
Moderate Minimal Moderate Moderate
No No No No
Marked increase Marked increase Marked increase Slight increase
45 45 30 30
11.
9 me.
Moderate
No change
Moderate increase
240
12.
18 too.
Moderate
No change
Moderate increase
30
13.
6 yr.
Minimal
No change
Marked increase
].
change change change change
]20
~EMAI~KS
I n f a n t burped before third film was taken Fig. 1 Fig. 2 Note air ingested with only 15 e.c. of milk. Fig. 3
I n f a n t burped before third film was taken Infant burped before third film was taken Milk ingested in two minutes Fluid gulped down in eight seconds. Fig. 4
GERBER:
GASTROINTESTINAL DISTENTION IN INFANTS
SoverP 4 found that infants do not swallow air by sucking on an empty bottle or their fingers. He concluded from his clinical experiments and x-ray studies that infants only swallow air during the act of deglutition. These observations obviously are in conflict with the beliefs of a good m a n y pediatricians. To evaluate Soveri's work, roentgenological studies were carried out on patients from the newborn n u r s e r y and the pediatric ward. Thirteen subjeers were chosen ranging in age from 12 days to 6 years. A preliminary scout film of the abdomen was taken following four to eight hours of fasting. The flat film was repeated after t h i r t y minutes of sucking on an empty bottle; the frustrated, younger subjects cried lustily for a p a r t of this time. A third film was taken after an oral intake of 15 to 120 c.c. of milk. The results are tabulated in Table II. Figs. 1 to 4 are representative films. The findings indicate that, contrary to popular opinion, air is not easily swallowed by infants except during deglutition. The fihns i n v a r i a b l y revealed no change in the stomach gas pattern following t h i r t y minutes of sucking on an empty bottle, but the stomach routinely appeared filled with air a f t e r the ingestion of milk. I n a few instances, the infant b u r p e d the air out before the t h i r d film could be taken, and there was minimal demonstrable roentgenographic change. The subject apparently swallowed two to three times as much air as fluid. The stomach of an infant was visualized following the injection of 75 c.c. of air which showed a gas bubble coinp a r i n g in size to the gas shadow formed by ingesting 30 c.c. of milk (Fig. 5).
69
Another investigation conclusively demonstrated that the stomach gas was swallowed air rather than the result of food decomposition or diffusion. Three subjects were allowed to ingest a measured amount of fluid, and at a subsequent time the same amount of fluid was gavaged. Films taken following gavage of fluids did not reveal the characteristic air-filled stomach (Fig. 6). These findings confirm Soveri's investigations. 14 F r o m a theoretical standpoint, it is difficnR to conceive of air entering tile stomach of infants with each inspiration. is I f as little as 0.1 e.e. of air was ingested with each inspiration, an i n f a n t with a respiratory rate of 36 would ingest more t h a n 2,500 c.c. of air in each twenty-four-hour period, exclusive of air swallowed during feeding. Atmospheric air is 80 per cent nitrogen which is poorly absorbed by the intestinal ~ract, and swallowed air is largely passed as flatus25 Adults usually egest between 500 and 1,000 e.e. of flatus per day, and the gastrointestinal tract contains an average of 1,300 e.e. of gas a t any one time. 1~ The concept of continuous, inspiratory air swallowing in infants seems unreasonable in view of these figures. Gastric tubes were passed on three infants in the nursery, and the free ends were placed u n d e r water. In each instance there was an immediate bubbling of gas as the stomach emptied, since the intragastric pressure is a positive 8 to 13 em. of water as is the intraperitoneal pressure.16, 17 There was no f u r t h e r passage of gas through the water with expiration, and thus Leigh and Belton's is findings could not be confirmed.
70
THE
JOURNAL
OF
A.
PEDIATRICS
B.
C.
Fig, 1,--Case
4, I n f a n t a g e d 18 d a y s . on an empty bottle,
A, F a s t i n g film. B, A f t e r s u c k i n g f o r t h i r t y min~l~e~ C, A f t e r i n g e s t i o n o f 45 c,c, o f m i l k ,
GERBER:
GASTROINTESTINAL
A.
Fig. 2.~Case
5, I n f a n t a g e d 21 d a y s . on an empty bottle.
DISTENTION
IN
INFANTS
71
B.
A, F a s t i n g film. B , A f t e r s u c k i n g f o r t h i r t y G, A f t e r i n g e s t i o n o f 30 e,c, o f m i l k .
minutes
72
THE
J O U R N A L OF P E D I A T R I C S
C. F i g . 3 . - - C a s e 6, I n f a n t a g e d 1 m o n t h . on a n e m p t y bottle.
A, F a s t i n g film. B, A f t e r s u c k i n g f o r t h i r t y m i n u t e s G, A f t e r i n g e s t i o n of 15 e.c. of m i l k .
GERBER:
A.
GASTROINTESTINAL DISTENTION IN
INFANTS
73
B.
Fig'. 4 . - - C a s e 13. I n f a n t a g e d 6 y e a r s . A, F a s t i n g film. B, A f t e r s u c k i n g f o r t h i r t y m i n u t e s on a n e m p t y bottle. C, A f t e r i n g e s t i o n of 120 e.c, of w a t e r in a f e w g u l p s .
74
Fig.
THE
5.--Infant
aged
5 months. stomach.
J O U R N A L OF P E D I A T R I C S
A b d o m i n a l film f o l l o w i n g i n j e c t i o n of C o m p a r e w i t h F i g s . l, 2, 3, a n d 4.
75 c.e. of a i r
into
~~ Fi~
6.--Infant
a g e d 21 d a y s .
A~ A f t e r i n g e s t i o n of 30 c.c. of m i l k . c.c. of m i l k .
B, A f t e r g a r a g e of 30
GERBER: DIFFUSION
OF
GASTROINTESTINAL DISTENTION IN GASES
The role of diffusion in the development of distention has been adequately stressed. Diffusion of gases into and out of the gastrointestinal tract unquestionably occurs and apparently does so in a manner conforming to gas laws. Gas under different pressures on two sides of a semipermeable membrane will diffuse until equilibrium is established. That intestinal gases obey this
.4_.
INFANTS
75
Dunn and Thompson is obtained the same results in experiments with human beings. Anderson and Ringsted 7 brilliantly analyzed the problem Of ileus from a theoretical consideration of the gas lairs and by animal experimentation. They eoneluded that intestinal distention is due almost entirely to swallowed air. They also claim that the physical laws prohibit diffusion of gases into
~,
Fig. 7.--Child aged 8 years. A, A c u t e d i l a t a t i o n of s t o m a c h in a n a g i t a t e d child i o r o b a b l y d u e to a s y m p a t h e t i c r e s p o n s e . B , N o r m a l fihn of sa~zle p a t i e n t .
law was Shown by Mclver and associates. 1~ When air (C02 = 0.04 vol. per cent) was introduced into the stomaeh of experimental animals, CO2 diffused into the stomach until the concentration was equal to that of the blood (C02 ~ 5.3 vol. per cent). Conversely, when air with a high percentage of CO~ was introduced, CO2 diffused out of the stomach into the blood until equilibrium was established.
the intestines u n d e r the circumstances that pertain in intestinal distention. How does one explain gastrointestinal distention when swallowed air apparently is no factor ? Wangensteen and Rea 4 produced an intestinal obstruction in a series of dogs by ligation of the distal ileum. A n u m b e r of these animals were then subjected to esophagostomy with inversion of the distal end, thus excluding swallowed
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THE JOURNAL OF PEDIATRICS
air from the intestinal tract. Two of these animals developed tremendous distention, more marked than any of the controls. The only explanation of this gas is diffusion, since the chief gaseous product of food fermentation is COs which is rapidly absorbed. I t is also difficult to explain acute gastric dilatation on the basis of swallowed air only. Fig. 7, A is an abdominal fihn of a fasting 8-year-old girl who became extremely agitated when told that she was to suck on a nipple bottle for t h i r t y minutes. The gastric dilatation evidently appeared in a matter of seconds. An abdominal film of the same subject, taken on another day when she was calm, is shown for comparison (Fig. 7, B). The sympathetic nervous system, which is predominantly inhibitory to the gastrointestinal tract, apparently played a role in this instance of gastric dilatation. Dragstedt ~9 has discussed the sympathetic and vagal factors in acute dilatation of the stomach. The role of the autonomie nervous system in the production of gastrointestinal distention is worthy of f u r t h e r investigation. Many questions concerning distention of the digestive tract remain unanswered. Despite the evidence that air swallowing takes place chiefly during deglutition, it has been shown that the newborn i n f a n t ' s stomach fills with air as soon as six minutes after birth, and subsequent films reveal the small and large intestine to be filled with gas. 2~ It seems to be conclusively established that the gas in the intestines of newborn infants is swallowed air, because no intestinal gas is found in a newborn infant with an esophageal atresia. No diffusion of gases can take place from the blood stream into the empty intestinal tract in accordance
with the gas laws2, 7 The rapid appearance of intestinal gas in the newborn infant may be a phenomenom peculiar to the first few hours of life. Perhaps the superior esophageal constrictor of the newborn infant is not as efficient a pinchcock as it is later in infancy and allows more air swallowing than one normally expects. The answer to this question must await f u r t h e r studies on the pneumodynamics of the digestive tract. SUM~IARY
Gastrointestinal gas is produced from food decomposition, swallowed air, and diffusion from the blood stream as established in previous studies on the subject. The x-ray investigations presented here were carried out to f u r t h e r evaluate the role of swallowed air in gaseous distention. These studies indicate that air is swa]lowed mainly during deglutition; little, if any, air is ingested while crying or sucking as is popularly believed. The suggestion that i n f a n t s normally ingest air during each inspiration has not been confirmed, although air swallowing unquestionably occurs during the first few minutes of life. F u r t h e r investigation of the behavior of intestinal gases is indicated, particularly the role of the autonomic nervous system in the production of gastrointes~ tinal distention. REFERENCES 1. Johnson, ~I. H.: Bridges Dietetics for the Clinician, Philadelphia, 1949, L e a & Febiger, p. 110. 2. Fine, J., and Levenson, W. S.: Effect of ]~oods on Postoperative Distention, Am. J. Surg. 21: 184, 1933. 3. Itibbard, J., and Wangensteen, 0. I~I.: Character of the Gaseous Distention in Mechanical Obstruction of the Small Intestine, Proc. Soe. Exper. Biol. & Med. 31: 1063, 1934.
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GASTROINTESTINAL DISTENTION IN INFANTS
4. Wangensteen, O. H., and t~ea, C. E.: The Distention Factor in Simple Intestinal Obstruction, Surgery 5: 327, ]939. 5. Mclver, M. A., Benedict, E. B., and Cline, J. W , J r . : Postoperative Gaseous Distention of the Intestines, Arch. Surg. 13: 588, 1926. 6. Maddock, W. G., Bell, J. L., and Tremaine~ M. J.: Gastrolntestinal Gas, Ann. Surg. 130: 512, 1949. 7. Anderson, K.~ and ]%iugsted, A.: Clinical and Experimental Investigations on Ilcus With Particular Reference to the Genesis of Intestinal Gas, Aeta chir. scandinav. 80: 475, 1943. 8. Begg, R. C.: A Rational Theory of Intestinal Distention and Its Urological Application, J. Urol. 59: 358, 1948. 9. Grulee, C. G., and Eley, R. C.: The Child in Health and Disease, Baltimore, 1948, Williams & Wilkins Co., p. 89. 10. Jeans, P. C., and Marriott, W . M . : Inf a n t Nutrition, ed. 4, St. Louis, 1947, The C. V. Mosby Co., p. 356. l l . Nelson, W . E . : Textbook of Pediatrics, ed. 5, Philadelphia, ]950, W. B. Saunders Co., p. 147. 12. Anderson, J. A.: B r e n n e m a n n ' s Practice of Pediatrics, Hagerstown, 1948~ W. F: Prior Co., vol. I~ chap. 27, p. 4.
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13. Leigh, M. C., and Belton, M. K, : Pediatric Anaesthesia, New York, 1953~ Tile Macmillan Co., p. 16. 14. Soveri, V.: Der Verlauf der L u f t dureh den Verdaungskanal des Sauglings, Acta paediat. (supp. 3) 23: 1, 1939. 15. McIver, M. A., Redfield, A. C., and Benedict, E . B . : Gaseous Exchange Be~ tween the Blood and the Lumen of the Stomach aud Intestines, Am. J. Physiol. 76: 92, 1926. 16. Blair~ H. A., Dern, i%. J., and Bates, P. L.: The Measurement of the Volume of Air in the Digestive Tract, Am. J. Physioh 149: 688, 1947. 17. Drye, J.C.: Intraperitoneal Pressure in the I~Iuman~ Surg.~ Gynee. & Obst. 87: 472, 1948. 18. Duun, A. D., and Thompson, W.: The Carbon Dioxide and Oxygen Content of Stomach Gas in Normal Persons, Arch. Int. Med. 31: 1, 1923. 19. I)ragstedt, L. R.: Acute Dilatation of the Stomach, Lewis' Practice of Surgery. I-Iagerstown, 1950, W. F. Prior Co., vol. 6, chap. 10. 20. Paine, J. R., and Nessa, C . B . : Observations on the Distribution and T r a n s p o r t of Gas in the Gastrointestinal Tract of Infants and Young Children, Surgery Ii: 281, 1942.