Acta Padiatr Scand 64: 253-256, 1975
SUBMAXIMAL BLOOD FLOW AND BLOOD VISCOSITY IN NEWBORN INFANTS GUDMUND BERGQVIST and ROLF ZETTERSTROM
ABSTRACT. Bergqvist, G . and Zetterstrom, R. (Department of Paediatrics, Karolinska Institutet, St Gotan's Children's Hospital, Stockholm, Sweden). Submaximal blood flow and blood viscosity in newborn infants. Acta Paediatr Scand, 63:253, 1974.-In newborn infants with varying hematocrit values the submaximal blood flow has been studied by the use of strain gauge plethysmography under standardized conditions. Submaximal flow was defined as the flow obtained after 4 minutes of suprasystolic occlusion. With increasing hematocrit there was a decreasing maximal flow. Capillary filtration coefficient seemed to decrease with increasing hematocrit. The relation between circulatory failure in newborns due to abnormaiij high hematocrit and low capacity to increase blood flow upon demand has been discussed.
KEY WORDS: Submaximal flow, blood viscosity, newborn infants, hematocrit, secondary polycythemia, pletysmography
In newborn infants there is a good correlation between blood viscosity and hematocrit, even if the viscosity increases much faster than the hematocrit (3). However, the resting muscular blood flow, as measured in the calf and foot, has been found to be unaltered by variations of blood viscosity and hematocrit (4). Even if the hematocrit is extremely high the resting flow remains normal. However, it is a w e l l h o w n fact that some newborn infants with high hematocrit (secondary polycythemia) develop symptoms of circulatory failurs (12, 15). If elevated blood viscosity is contributory, the hypothesis may be advanced that maximal flow is reduced although resting flow does not vary with the hemdocrit. T o elucidate this possibility the following study was made. This study has been s u p p ~ t e dby grants from Crown Princess Lovis; ' s Fou,idatioii for Child Health and Axel Tielman Foundation.
MATEKIAL AND METHODS All infants had normal deliveries with Apgar scores of 9 or 10 at I minute. Nothing abnormal was found during the first week of life. A. The babies of groups Al and A2 were included in a pilot study. A l : Ten I-day-old full-term infants with a mean birth weight of 3550 g (S.D. 495 g) and a mean gestational age of 40.4 weeks (S.D. 1.8 weeks). A2: Eleven 3-day-old infants with a mean birth weight of 3370 g (S.D. 710 g) and a mean gestational age of 39.5 weeks (S.D. 2.3 weeks). The range for gestational age for these pilot groups was 37 to 42 weeks. B. Fourteen I-day-old (20 to 36 hours) term infants with a mean birth weight of 3490 g (S.D. 410 g) and a mean gestational age of 39.9 weeks (S.D. 1.0 weeks). All infants had normal deliveries with Apgar scores of 9 or 10 at 1 minute and were regarded a s healthy. When the infants included in groups A l and A2 were studied they were, lying in ordinary cots with double blankets. Room te,mperature was 23.0"C and the temperature under the blankets at the skin 32.0"C. The infants belonging to group B were dressed and placed in an incubator at a temperature of 32.0"C. Most probably all of the babies examined were kept within the neutral temperature zone, where muscular blood flow (i.e. calf and foot) is reported to be stable (2). The infants in group B were examined 14-2 hours after feeding. Acfo Pzdiorr Scond 64
254
G. Bergyiist arid R. Zetterstriirii f h h
1-s Resting f
10
0
.
A
.
A A
a
* .a
a
A
.
A a.
A
50
55
60
65
venous
70
75
hematocrit
Fig. 1 . Relationships between hematocrit and the sub-
maximal/resting blood flow ratio in 21 newborn infants. Ten were 1 day old ( 0 )and eleven were 3 days old (A).
Maximal flow (i.e. submaximal flow) was measured in the calf and defined as the flow after 4 min of suprasystolic occlusion with a pressure of 150 to 200 mmHg and 5 to 10 sec after cessation of the occlusion. The usual occlusive pressure for flow measurements was 40 mmHg. The strain gauge was placed on the calf at the largest circumference. Capillary filtration coefficient (CFC) W R S measured in 9 of the babies included in group B prior to the determination of arterial blood pressure and maximal flow. The occlusive pressures were 20 or 30 mmHg and 40 mmHg. respectively. Precapillary resistance was assumed to be 80% (9, 14). CFC was also determined in the same way in another two healthy I-day old infants with body weight 3 490-3 720 g and venous hct 6 6 7 2 %. A strain gauge plethysmograph was used (7, 17) (LPM periquant 11). The technical aspects of this equipment have been described by Gutman (12) and Schreiber (16). Hematocrit was determined as in earlier studies (3).
examined on the first or second day, i.e. 30 to 36 hours after birth. Correlation analysis of the hematocrit/flow ratio shows this to be significant @. A[,rti Ptrcdicctr S t , < i n d ,60: 278. 1971. 3 . Bergqvist. G . : Viscosity of the blood in the newborn infant. Act0 Paediatr Sctrnd. 63: 858, 1974. 4 . Bergqvist, G . & Zetterstriim, R.: Blood viscosity and peripheral circulation in newborn infants. A(,ftc P i r ~ diotr Scund, 63: 865, 1974. 5 Bollinger, A . & Luthy. E.: Blood viscoxity a n d blood flow in the human forearm. H c h . hlcd Ac,ftr. 34: fasc 3: 255. 1968. 6 Celander. 0.: Blood flow in the foot and calf of the newborn. Arta Paediair Scand, 49: 488. 1960. 7 Celander. 0. & Thunell. G.: The mercury in rubber strain gauge for instrument3 of blood pressure and peripheral circulation i n the newborn infants. Ac,tir Ptrrdicrtr Sc(rnr1, SO: 505. 1961. 8 Celander. 0. & Mirild, K.: Reactive hypereria in the foot and calf of the newborn infant. Acitr P t r ~ dicrir S t a n d . 51: 554. 1962. 9 - Regional circulation and capillary filtration in rclation !o capi!!ary exctazge in the foot and calf Arta Padiatr Scand 64
256 G . Bergqvist and R . Zetterstrom
10. I I.
I?.
13. 14.
15.
of the newborn infant. Acttr Puediatr Scund, 51: 385, 1962. Dintenfass, L.: Blood microrheology. Butterworths, London, I97 1. Fouron. J. C. & Hkbert, F.: The circulatory effects of hematocrit variations in normovolemic newborn lambs. J Pctiintr. 82: 995, 1973. Gross, G. P., H a t h w a y , W. E. & McCaughey, H. R.: Hyperviscosity in the neonate. J Pediatr, 817: 1004, 1973. Gutman, J . : Moderne Geratetechnik fur Venenverschlussplethysrnografie. HerzlKreisl, 3: 365, 1971. Kjellmer, I . : The effect of exercise of the vascular bed of skeletal muscle. ActLi Physiol Scand, 62: 18, 1964. Kontras, S . B.: Polycythemia and hyperviscosity
Actu Pzdiutr Scund 64
syndromes in infants and children. Pediutr CIin North A m , 19: 919, 1972. 16. Schreiber, H.: Die Venenverschluss-pletysmographie in der Fachpraxis. Medicinal marktlarta medicotechnics, 18: 37, 1970. 17. Whitney, R. J.: The measurement of volume chaqges in human limbs. J Physiol (London), 121: 1, 1953.
Submitted March 22, 1974 Accepted March 22, 1974 (G. B.) Dept. of Paediatrics S:t Goran’s Sjukhus Box 12500 S-1 12 81 Stockholm Sweden
SUBMAXIMAL BLOOD FLOW AND BLOOD VISCOSITY IN NEWBORN INFANTS GUDMUND BERGQVIST and ROLF ZETTERSTROM
ABSTRACT. Bergqvist, G . and Zetterstrom, R. (Department of Paediatrics, Karolinska Institutet, St Gotan's Children's Hospital, Stockholm, Sweden). Submaximal blood flow and blood viscosity in newborn infants. Acta Paediatr Scand, 63:253, 1974.-In newborn infants with varying hematocrit values the submaximal blood flow has been studied by the use of strain gauge plethysmography under standardized conditions. Submaximal flow was defined as the flow obtained after 4 minutes of suprasystolic occlusion. With increasing hematocrit there was a decreasing maximal flow. Capillary filtration coefficient seemed to decrease with increasing hematocrit. The relation between circulatory failure in newborns due to abnormaiij high hematocrit and low capacity to increase blood flow upon demand has been discussed.
KEY WORDS: Submaximal flow, blood viscosity, newborn infants, hematocrit, secondary polycythemia, pletysmography
In newborn infants there is a good correlation between blood viscosity and hematocrit, even if the viscosity increases much faster than the hematocrit (3). However, the resting muscular blood flow, as measured in the calf and foot, has been found to be unaltered by variations of blood viscosity and hematocrit (4). Even if the hematocrit is extremely high the resting flow remains normal. However, it is a w e l l h o w n fact that some newborn infants with high hematocrit (secondary polycythemia) develop symptoms of circulatory failurs (12, 15). If elevated blood viscosity is contributory, the hypothesis may be advanced that maximal flow is reduced although resting flow does not vary with the hemdocrit. T o elucidate this possibility the following study was made. This study has been s u p p ~ t e dby grants from Crown Princess Lovis; ' s Fou,idatioii for Child Health and Axel Tielman Foundation.
MATEKIAL AND METHODS All infants had normal deliveries with Apgar scores of 9 or 10 at I minute. Nothing abnormal was found during the first week of life. A. The babies of groups Al and A2 were included in a pilot study. A l : Ten I-day-old full-term infants with a mean birth weight of 3550 g (S.D. 495 g) and a mean gestational age of 40.4 weeks (S.D. 1.8 weeks). A2: Eleven 3-day-old infants with a mean birth weight of 3370 g (S.D. 710 g) and a mean gestational age of 39.5 weeks (S.D. 2.3 weeks). The range for gestational age for these pilot groups was 37 to 42 weeks. B. Fourteen I-day-old (20 to 36 hours) term infants with a mean birth weight of 3490 g (S.D. 410 g) and a mean gestational age of 39.9 weeks (S.D. 1.0 weeks). All infants had normal deliveries with Apgar scores of 9 or 10 at 1 minute and were regarded a s healthy. When the infants included in groups A l and A2 were studied they were, lying in ordinary cots with double blankets. Room te,mperature was 23.0"C and the temperature under the blankets at the skin 32.0"C. The infants belonging to group B were dressed and placed in an incubator at a temperature of 32.0"C. Most probably all of the babies examined were kept within the neutral temperature zone, where muscular blood flow (i.e. calf and foot) is reported to be stable (2). The infants in group B were examined 14-2 hours after feeding. Acfo Pzdiorr Scond 64
254
G. Bergyiist arid R. Zetterstriirii f h h
1-s Resting f
10
0
.
A
.
A A
a
* .a
a
A
.
A a.
A
50
55
60
65
venous
70
75
hematocrit
Fig. 1 . Relationships between hematocrit and the sub-
maximal/resting blood flow ratio in 21 newborn infants. Ten were 1 day old ( 0 )and eleven were 3 days old (A).
Maximal flow (i.e. submaximal flow) was measured in the calf and defined as the flow after 4 min of suprasystolic occlusion with a pressure of 150 to 200 mmHg and 5 to 10 sec after cessation of the occlusion. The usual occlusive pressure for flow measurements was 40 mmHg. The strain gauge was placed on the calf at the largest circumference. Capillary filtration coefficient (CFC) W R S measured in 9 of the babies included in group B prior to the determination of arterial blood pressure and maximal flow. The occlusive pressures were 20 or 30 mmHg and 40 mmHg. respectively. Precapillary resistance was assumed to be 80% (9, 14). CFC was also determined in the same way in another two healthy I-day old infants with body weight 3 490-3 720 g and venous hct 6 6 7 2 %. A strain gauge plethysmograph was used (7, 17) (LPM periquant 11). The technical aspects of this equipment have been described by Gutman (12) and Schreiber (16). Hematocrit was determined as in earlier studies (3).
examined on the first or second day, i.e. 30 to 36 hours after birth. Correlation analysis of the hematocrit/flow ratio shows this to be significant @. A[,rti Ptrcdicctr S t , < i n d ,60: 278. 1971. 3 . Bergqvist. G . : Viscosity of the blood in the newborn infant. Act0 Paediatr Sctrnd. 63: 858, 1974. 4 . Bergqvist, G . & Zetterstriim, R.: Blood viscosity and peripheral circulation in newborn infants. A(,ftc P i r ~ diotr Scund, 63: 865, 1974. 5 Bollinger, A . & Luthy. E.: Blood viscoxity a n d blood flow in the human forearm. H c h . hlcd Ac,ftr. 34: fasc 3: 255. 1968. 6 Celander. 0.: Blood flow in the foot and calf of the newborn. Arta Paediair Scand, 49: 488. 1960. 7 Celander. 0. & Thunell. G.: The mercury in rubber strain gauge for instrument3 of blood pressure and peripheral circulation i n the newborn infants. Ac,tir Ptrrdicrtr Sc(rnr1, SO: 505. 1961. 8 Celander. 0. & Mirild, K.: Reactive hypereria in the foot and calf of the newborn infant. Acitr P t r ~ dicrir S t a n d . 51: 554. 1962. 9 - Regional circulation and capillary filtration in rclation !o capi!!ary exctazge in the foot and calf Arta Padiatr Scand 64
256 G . Bergqvist and R . Zetterstrom
10. I I.
I?.
13. 14.
15.
of the newborn infant. Acttr Puediatr Scund, 51: 385, 1962. Dintenfass, L.: Blood microrheology. Butterworths, London, I97 1. Fouron. J. C. & Hkbert, F.: The circulatory effects of hematocrit variations in normovolemic newborn lambs. J Pctiintr. 82: 995, 1973. Gross, G. P., H a t h w a y , W. E. & McCaughey, H. R.: Hyperviscosity in the neonate. J Pediatr, 817: 1004, 1973. Gutman, J . : Moderne Geratetechnik fur Venenverschlussplethysrnografie. HerzlKreisl, 3: 365, 1971. Kjellmer, I . : The effect of exercise of the vascular bed of skeletal muscle. ActLi Physiol Scand, 62: 18, 1964. Kontras, S . B.: Polycythemia and hyperviscosity
Actu Pzdiutr Scund 64
syndromes in infants and children. Pediutr CIin North A m , 19: 919, 1972. 16. Schreiber, H.: Die Venenverschluss-pletysmographie in der Fachpraxis. Medicinal marktlarta medicotechnics, 18: 37, 1970. 17. Whitney, R. J.: The measurement of volume chaqges in human limbs. J Physiol (London), 121: 1, 1953.
Submitted March 22, 1974 Accepted March 22, 1974 (G. B.) Dept. of Paediatrics S:t Goran’s Sjukhus Box 12500 S-1 12 81 Stockholm Sweden
