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Tracheal fluid and respiratory distress
5 78
Abstracts
ter through the femoral vein up to the right atrium and manipulated the catheter through the foramen ovale and into the left atrium, and this was the site of the injection of the dye. Then we inserted an arterial catheter through one of the carotid arteries, and under fluoroscopic vision positioned the tip of the catheter so it was just above the aortic valve and proximal to the origin of the dnctus arteriosus. The curve was a sharp curve and no evidence of right or left shunting was demonstrated on the dye-dilution curves. DR. WEIDMAN. HOW much blood did you have to take out before the dye recirculated ? DR. HERNANDEZ. We took out about 20 to 25 c.c. of blood for dye-dilution curves after the determination was completed. We injected the Mood back into the ferns and tried not to exsanguinate it. DR. WEmMAN. Would withdrawal of 25 c.c. of blood change the cardiac output ? DR. HERNA,XDEZ. I don't think so the control groups showed the same features
16. Fetal and placental relationships in normal and intrauterine growthretarded infants M. K. Younoszai arad J. C. Haworth, Winnipeg, Man.. Canada. Eighty-five placentas of normal infants and 52 pIacentas of intrauterine growth-retarded infants were studied. All the infants were of more than 37 weeks' gestation. Placental weight, decidual surface area, thickness, and cord diameter were measured and the infant weight/placental weight ratio was calculated. In the growth-retarded infants, the mean placental weight, surface area, and cord diameter were significantly smaller compared with the normals. However, the mean thickness and infant weight/placental weight ratio were not significantly different. In the normal infants, infant weight showed a significant positive correlation with placental weight and decidual surface area. In the growth-retarded infants, there was not a significant correlation between infant and placental weight, but infant weight showed a significant positive correlation with placental area and a significant negative correlation with placental thickness. These results suggest that the area of placental attachment to the uterus is a most important determinant of infant weight. Furthermore, increased thickness of the placenta may have a growthretarding effect on the fetus. DISCUSSION DR. BERMAN, Chicago. What was the criterion for including a child in a study as an intrauterine growth-retarded infant? Was it birth weight? DR. YouxoszAr. It was birth weight that was under the tenth percentile on the Denver Growth Chart. DR. 0i-I, Chicago. I wonder if you have controlled the time of cord clamping at birth which could conceivably influence placental weight?
The Journal of Pediatrics April 1968
DR. YOUNOSZAI. In the first place, we have drained most of the blood from the placentas. It is the policy at our hospital that after birth the infant is held below the mother's perineum for a minute or two and the cord is clamped at that time. I think the cord clamping would be a relatively constant factor. Dm KERR, Madison. I must have missed one of your definitions of measurement. I would think that measuring the thickness of the placenta would be most difficult and would depend on which part of the cotyledonous surface thickness was being measured. In addition, as the thickness of the placenta tends to diminish toward the periphery, I think this would leave a fair range of error to be considered. Dm YOUNOSZAL I agree with you. We have estimated the mean thickness of the placenta by" dividing the volume by the surface area of the placenta. DR. ROaERTSON, Columbus. Could you tell me what the physiologic significance of thickness is? DR. YOUNOSZAI. I am afraid not.
17. Tracheal fluid and respiratory distress L. Fagan, St. Louis, Mo. Introduced by A. McElfresh, St. Louis, 2V[o. It has been demonstrated that tracheal fluid is different from amniotic fluid; is produced in the lungs, and flows proximally toward the pharynx where it is swallowed. Its role during adaptation from fetal to neonatal existence has not been elucidated. Data derived over 5 years from experiments on lambs delivered by section show that, if tracheal fluid is not removed prior to cord ligation, fetal adaptation to neonatal existence is severely hampered. This conclusion is based on the following data: (1) Fetal lung weights of lambs are more than twice those of neonatal lung weights (i.e., lung weights of lambs delivered vaginally and put to death at 24 hours). (2) Lung weights of lambs delivered by section are similar to fetal tung weights. (3) Lung weights of lambs delivered vaglnally are LESS than neonatal lung weights. (4) With twins delivered by section, removal by suctioning of tracheal fluid from one twin prior to cord ligation improved sm~'ival and lessened the severity of respiratory distress as compared with the nonsuctioned twin. (5) Breathing, i.e., respiratory movement, is not synonymous with ventilation, i.e., gas exchange at the alveolar-capillary membrane, if tracheal fluid is present. (6) Fetuses, delivered by section, spontaneously removed tracheal fluid if sufficient time was allowed to establish ventilation prior to cord ligation. DISCUSSION DR. KRIEaER, Detroit. Were the experimental conditions that prevailed, when the lambs were either suetioned or sham suctioned, equal with
Volume 72
Abstracts 5 7 9
Number 4
respect to respiratory efforts and swallowing? You seem to equate tracheal with alveolar fluid, and assume that the major portion of it exits through the trachea. Do you envision that tracheal suction will remove alveolar fluid ? DR. t~AGAN. Your first question concerns a comparison of respiratory effort and swallowing between the two groups. Obviously, the onset of respirations after cord clamping is important. Asphyxia will vary depending if onset of respirations is 1 minute or 5 minutes. We have measured the onset of respirations and the number of respirations but not the effectiveness of these respirations. Therefore, we can compare the two groups only by onset and number of initial respirations. There was no difference in these when the two groups were compared. Your second question concerns the important point of swallowing. This fluid, obviously, if it has to get out of the air spaces, either goes back to the lung tissue where it came from or out through the glottis and is swallowed. We have measured swallowing in every one of our experiments. There is definitely a correlation with better survival when there are more acts of swallowing, although the amount swallowed has not been quantitated. I do not know whether the fluid produced in the lungs originates at the alveolar level or from higher up. I do envision that it comes from the alveolar level. Obviously, we do not suction much fluid beyond the accessibility of the catheter. However, this accessible fluid seems to be important at the time of birth as demonstrated by our experiments. DR. OH, Chicago. Are the lambs delivered at term ? This is not the place to discuss the merits of early and late cord clamping but I wonder if you would apply your experiment to term vaginal deliveries in relation to timing of cord clamping? DR. FAOAN. In vaginal deliveries ? DR. OH. Yes. In the study we did in Stockholm (Acta pedlar, scandinav. 55: 17, 1966), the first breath occurred sooner when the cord was clamped early. The lung compliance, which reflects the mechanical property of the lung is greater in early-clamped infants than in lateclamped groups (Pediatrics 40: 6, 1966). DR. FAGAN. The cesarean-sectioned lambs were delivered between 142 to 145 days and we considered them to be at term. Our vaginally delivered lambs obviously were at term. All of the fetuses delivered vaginally were breathing before we could clamp the cord. In most cases, I do not think one can attend the full-term vaginally delivered lamb and clamp the cord before it is breathing. Furthermore, at vaginal deliveries of full-term fetuses, I do not think it makes much difference when the cord is clamped. I do think, however, that when we are dealing with cesarean sections, with premature births, or with precipitate deliveries, i.e., those not undergoing compression of the chest during delivery, it might make a very large difference.
18. The physiologic significance o/ grunting respiration J. H. Knelson, W. F. Howatt, and G. R. DeMuth, Ann Arbor, Mich. Grunting respiration is seen in a variety of clinical entities and is especially prominent in such pediatric problems as the respiratory distress syndrome and pneumonia. The "grunt" in grunting respiration occurs when the epiglottis is relaxed following an end-inspiratory pause. An experimental preparation was devised to study the physiologic significance of this particular respiratory pattern. Healthy, adult dogs were anesthetized, given a continuous succinylcholine infusion, and ventilated through a tracheostomy with a piston respirator. A solenoid valve permitted us to shift from the normal end-expiratory pause to an end-inspiratory pause of equal duration without changing respiratory rate or tidal volume. We compared the effects of the normal and abnormal respiratory pattern on arterial pO:, pCO.~, pH, and mean expired COz. These studies were carried out at varying levels of minute ventilation in 11 healthy dogs and in 5 dogs with kerosene pneumonitis. The experimental pneumonitis was induced with intravenous injection of kerosene which is rapidly excreted by the lungs, causing relatively reproducible lesions. Dogs with pneumonia and those without demonstrated a significant improvement in oxygenation and the elimination of CO.o when the grunting pattern of respiration was substituted for the normal one. T h e degree of improvement was directly related to the degree of hypoventilation in both normal and abnormal. These studies indicate that, in animals with experimental pneumonitls and in those with normal lungs, a clear-cut physiologic advantage is seen when the pattern of respiration is shifted from normal to one simulating grunting respiration. DISCUSSION DR. T~trRSTON, St. Loub. Have you investigated the effectiveness of the terminal "gasp" with respect to normal inspiration? DR. KNELSOX. NO, we have not.
I9. Benefit o/ early vs. late feeding
o/
intrauterine [etally malnourished (IUM) in/ants W . O h , I. F. R a b o r , P. Y. K . W u , a n d
J.
M e t c o f f , C h i c a g o , Ill.
The biochemical effects of early versus late feeding were evaluated in 28 intrauterine fetally malnourished ( I U M ) infants. The criteria for I U M include: (1) birth weight below the tenth percentile of Colorado's growth chart, (2) body length longer for weight, and (3) signs of dysmaturity described by Clifford (Adv. Pediat. 9: 13, 1957). In I3 I U M infants weighing more than 2,040 grams at birth, the blood-glucose levels, acid-base status, and serum calcium and
Abstracts
ter through the femoral vein up to the right atrium and manipulated the catheter through the foramen ovale and into the left atrium, and this was the site of the injection of the dye. Then we inserted an arterial catheter through one of the carotid arteries, and under fluoroscopic vision positioned the tip of the catheter so it was just above the aortic valve and proximal to the origin of the dnctus arteriosus. The curve was a sharp curve and no evidence of right or left shunting was demonstrated on the dye-dilution curves. DR. WEIDMAN. HOW much blood did you have to take out before the dye recirculated ? DR. HERNANDEZ. We took out about 20 to 25 c.c. of blood for dye-dilution curves after the determination was completed. We injected the Mood back into the ferns and tried not to exsanguinate it. DR. WEmMAN. Would withdrawal of 25 c.c. of blood change the cardiac output ? DR. HERNA,XDEZ. I don't think so the control groups showed the same features
16. Fetal and placental relationships in normal and intrauterine growthretarded infants M. K. Younoszai arad J. C. Haworth, Winnipeg, Man.. Canada. Eighty-five placentas of normal infants and 52 pIacentas of intrauterine growth-retarded infants were studied. All the infants were of more than 37 weeks' gestation. Placental weight, decidual surface area, thickness, and cord diameter were measured and the infant weight/placental weight ratio was calculated. In the growth-retarded infants, the mean placental weight, surface area, and cord diameter were significantly smaller compared with the normals. However, the mean thickness and infant weight/placental weight ratio were not significantly different. In the normal infants, infant weight showed a significant positive correlation with placental weight and decidual surface area. In the growth-retarded infants, there was not a significant correlation between infant and placental weight, but infant weight showed a significant positive correlation with placental area and a significant negative correlation with placental thickness. These results suggest that the area of placental attachment to the uterus is a most important determinant of infant weight. Furthermore, increased thickness of the placenta may have a growthretarding effect on the fetus. DISCUSSION DR. BERMAN, Chicago. What was the criterion for including a child in a study as an intrauterine growth-retarded infant? Was it birth weight? DR. YouxoszAr. It was birth weight that was under the tenth percentile on the Denver Growth Chart. DR. 0i-I, Chicago. I wonder if you have controlled the time of cord clamping at birth which could conceivably influence placental weight?
The Journal of Pediatrics April 1968
DR. YOUNOSZAI. In the first place, we have drained most of the blood from the placentas. It is the policy at our hospital that after birth the infant is held below the mother's perineum for a minute or two and the cord is clamped at that time. I think the cord clamping would be a relatively constant factor. Dm KERR, Madison. I must have missed one of your definitions of measurement. I would think that measuring the thickness of the placenta would be most difficult and would depend on which part of the cotyledonous surface thickness was being measured. In addition, as the thickness of the placenta tends to diminish toward the periphery, I think this would leave a fair range of error to be considered. Dm YOUNOSZAL I agree with you. We have estimated the mean thickness of the placenta by" dividing the volume by the surface area of the placenta. DR. ROaERTSON, Columbus. Could you tell me what the physiologic significance of thickness is? DR. YOUNOSZAI. I am afraid not.
17. Tracheal fluid and respiratory distress L. Fagan, St. Louis, Mo. Introduced by A. McElfresh, St. Louis, 2V[o. It has been demonstrated that tracheal fluid is different from amniotic fluid; is produced in the lungs, and flows proximally toward the pharynx where it is swallowed. Its role during adaptation from fetal to neonatal existence has not been elucidated. Data derived over 5 years from experiments on lambs delivered by section show that, if tracheal fluid is not removed prior to cord ligation, fetal adaptation to neonatal existence is severely hampered. This conclusion is based on the following data: (1) Fetal lung weights of lambs are more than twice those of neonatal lung weights (i.e., lung weights of lambs delivered vaginally and put to death at 24 hours). (2) Lung weights of lambs delivered by section are similar to fetal tung weights. (3) Lung weights of lambs delivered vaglnally are LESS than neonatal lung weights. (4) With twins delivered by section, removal by suctioning of tracheal fluid from one twin prior to cord ligation improved sm~'ival and lessened the severity of respiratory distress as compared with the nonsuctioned twin. (5) Breathing, i.e., respiratory movement, is not synonymous with ventilation, i.e., gas exchange at the alveolar-capillary membrane, if tracheal fluid is present. (6) Fetuses, delivered by section, spontaneously removed tracheal fluid if sufficient time was allowed to establish ventilation prior to cord ligation. DISCUSSION DR. KRIEaER, Detroit. Were the experimental conditions that prevailed, when the lambs were either suetioned or sham suctioned, equal with
Volume 72
Abstracts 5 7 9
Number 4
respect to respiratory efforts and swallowing? You seem to equate tracheal with alveolar fluid, and assume that the major portion of it exits through the trachea. Do you envision that tracheal suction will remove alveolar fluid ? DR. t~AGAN. Your first question concerns a comparison of respiratory effort and swallowing between the two groups. Obviously, the onset of respirations after cord clamping is important. Asphyxia will vary depending if onset of respirations is 1 minute or 5 minutes. We have measured the onset of respirations and the number of respirations but not the effectiveness of these respirations. Therefore, we can compare the two groups only by onset and number of initial respirations. There was no difference in these when the two groups were compared. Your second question concerns the important point of swallowing. This fluid, obviously, if it has to get out of the air spaces, either goes back to the lung tissue where it came from or out through the glottis and is swallowed. We have measured swallowing in every one of our experiments. There is definitely a correlation with better survival when there are more acts of swallowing, although the amount swallowed has not been quantitated. I do not know whether the fluid produced in the lungs originates at the alveolar level or from higher up. I do envision that it comes from the alveolar level. Obviously, we do not suction much fluid beyond the accessibility of the catheter. However, this accessible fluid seems to be important at the time of birth as demonstrated by our experiments. DR. OH, Chicago. Are the lambs delivered at term ? This is not the place to discuss the merits of early and late cord clamping but I wonder if you would apply your experiment to term vaginal deliveries in relation to timing of cord clamping? DR. FAOAN. In vaginal deliveries ? DR. OH. Yes. In the study we did in Stockholm (Acta pedlar, scandinav. 55: 17, 1966), the first breath occurred sooner when the cord was clamped early. The lung compliance, which reflects the mechanical property of the lung is greater in early-clamped infants than in lateclamped groups (Pediatrics 40: 6, 1966). DR. FAGAN. The cesarean-sectioned lambs were delivered between 142 to 145 days and we considered them to be at term. Our vaginally delivered lambs obviously were at term. All of the fetuses delivered vaginally were breathing before we could clamp the cord. In most cases, I do not think one can attend the full-term vaginally delivered lamb and clamp the cord before it is breathing. Furthermore, at vaginal deliveries of full-term fetuses, I do not think it makes much difference when the cord is clamped. I do think, however, that when we are dealing with cesarean sections, with premature births, or with precipitate deliveries, i.e., those not undergoing compression of the chest during delivery, it might make a very large difference.
18. The physiologic significance o/ grunting respiration J. H. Knelson, W. F. Howatt, and G. R. DeMuth, Ann Arbor, Mich. Grunting respiration is seen in a variety of clinical entities and is especially prominent in such pediatric problems as the respiratory distress syndrome and pneumonia. The "grunt" in grunting respiration occurs when the epiglottis is relaxed following an end-inspiratory pause. An experimental preparation was devised to study the physiologic significance of this particular respiratory pattern. Healthy, adult dogs were anesthetized, given a continuous succinylcholine infusion, and ventilated through a tracheostomy with a piston respirator. A solenoid valve permitted us to shift from the normal end-expiratory pause to an end-inspiratory pause of equal duration without changing respiratory rate or tidal volume. We compared the effects of the normal and abnormal respiratory pattern on arterial pO:, pCO.~, pH, and mean expired COz. These studies were carried out at varying levels of minute ventilation in 11 healthy dogs and in 5 dogs with kerosene pneumonitis. The experimental pneumonitis was induced with intravenous injection of kerosene which is rapidly excreted by the lungs, causing relatively reproducible lesions. Dogs with pneumonia and those without demonstrated a significant improvement in oxygenation and the elimination of CO.o when the grunting pattern of respiration was substituted for the normal one. T h e degree of improvement was directly related to the degree of hypoventilation in both normal and abnormal. These studies indicate that, in animals with experimental pneumonitls and in those with normal lungs, a clear-cut physiologic advantage is seen when the pattern of respiration is shifted from normal to one simulating grunting respiration. DISCUSSION DR. T~trRSTON, St. Loub. Have you investigated the effectiveness of the terminal "gasp" with respect to normal inspiration? DR. KNELSOX. NO, we have not.
I9. Benefit o/ early vs. late feeding
o/
intrauterine [etally malnourished (IUM) in/ants W . O h , I. F. R a b o r , P. Y. K . W u , a n d
J.
M e t c o f f , C h i c a g o , Ill.
The biochemical effects of early versus late feeding were evaluated in 28 intrauterine fetally malnourished ( I U M ) infants. The criteria for I U M include: (1) birth weight below the tenth percentile of Colorado's growth chart, (2) body length longer for weight, and (3) signs of dysmaturity described by Clifford (Adv. Pediat. 9: 13, 1957). In I3 I U M infants weighing more than 2,040 grams at birth, the blood-glucose levels, acid-base status, and serum calcium and