Venous and Capillary Hematocrit in Newborn Infants and Placental Transfusion

Hematocrit values were measured on one hundred and eleven sets of capillary (from unwarmed and warmed heels) and venous blood samples obtained simultaneously during the first 5 days of life from 60 full term newborn infants, 40 of which the umbilical cords were clamped late, and 20 clamped early a t the time of birth. In the late clamped infants, the capillary hematocrits showed an initial rise during the first 6 hours of life seemingly due to fluid transudation in the capillary beds, followed by a fall a t 12 to 24 hours of age due to a subsequent fluid reabsorption into the vascular space in response to increasing circulatory demands in the visceral organs. In the early clamped infants, the capillary hematocrits remained stable during the first 6 hours, but a slight decline was observed a t 12 to 24 hours of age. The simultaneously measured venous hematocrits of both late and early clamped infants plotted against age revealed a strikingly similar pattern of alterations. A marked capillary venous hematocrit difference was observed in the late clamped infants and to a much lesser extent in the early clamped infants during the first 5 days of life, with the venous being lower than the capillary values. Warming the heels prior to capillary sampling improves the capillary venous hematocrit correlations in the late clamped infants and the improvement achieved by this procedure increases as the infant becomes older. In the early clamped infants heel warming produces relatively less effects because there was less capillary venous hematocrit discrepancy initially. In infants over 12 hours of age where venipuncture is difficult or inadvisable, capillary blood samples obtained from warmed heels could be used for hematocrit measurements. However, the hematoples do not exactly correspond with the venous values and the approximate venous reading could be estimated by using the regression lines derived from our samples, and their 95% confidence limit could be calculated from the appropriate formulas.     

SERUM LEVELS OF THYROTROPIN, THYROXINE AND TRIIODOTHYRONINE IN FULLTERM, SMALL-FOR-GESTATIONAL AGE AND PRETERM NEWBORN BABIES

Abstract. Simultaneous serum concentrations of TSH, total thyroxine (T₄) and triiodothyronine (T₃) were determined in 93 fullterm (FT), 37 small-for-gestational age (SGA) and 38 preterm (PT) babies with a postnatal age from 2 to 144 hours. In addition, TSH, T₄ and T₃ concentrations were measured in cord sera from 27 FT, 4 SGA and 5 PT babies and in venous blood from 20 mothers at delivery. Cord blood concentrations of TSH were higher and T₄ and T₃ concentrations were lower than seen in the mothers. Serum concentrations of TSH were high during the first day of life followed by a decline. There was no statistically significant difference between serum TSH concentrations of the three groups of newborns. On the 5th day of life no elevated serum TSH values were found in any of the groups (TSH<5mU/l). Serum concentrations of thyroid hormones increased after birth and reached maximum levels within 24 hours in all groups. The relative increases above cord level were of the same magnitude in the newborns: Two times for serum T₄ and six times for serum T₃. The thyroid hormone concentrations in blood samples from FT babies decreased from the second day of life, whereas in low birth weight newborns the decreases were more variable. The serum levels of T₄ and T₃ were significantly different in the three groups of newborns, the highest values were seen in FT and the lowest values in PT babies. In contrast, the ratios between molar serum concentrations of T₄ and T₃ were found to be highest in PT, lower in SGA and lowest in FT babies, approaching maternal values during the first week of life. The data are discussed with regard to hormone secretion, thyroxine-binding capacity and peripheral T₄ to T₃ conversion in the three groups of newborns. It is concluded that from day 5 after birth serum TSH determinations, alone or in combination with serum T₄, seem to be the method of choice in screening for congenital hypothyroidism.     

The Circulatory and Respiratory Adaptation to Early and Late Cord Clamping in Newborn Infants

Time of first breath and frist cry, systolic blood pressure, pulse rate and respiratory rate of 32 newborn infants whose umbilical cords were clamped early and 30 whose cords were tied late after birth were studied. The early clamped infants breathed significantly sooner after birth than the late clamped infants, probably a result of anoxia due to severance of placental blood supply by immediate cord clamping. The indirectly measured sys- tolic blood pressure was significantly higher in the late clamped group of infants during the first 24 hours of life perhaps due to the difference in blood volumes between the two groups. This is further supported by a positive correlation found between systolic blood pressure and venous hematocrit during the first 4 hours of life. Pulse rate in the two groups of infants studied revealed no significant difference. The respiratory rate in the early clamped group of infants was significantly slower during the 1st to the 3rd hour of life when compared with the late clamped infants. No satisfactory explanation could be offered for this observation.     

Early versus late cord clamping: effects on peripheral blood flow and cardiac function in term infants

BACKGROUND: In the debate on the best cord clamping time in newborn infants, we hypothesized that late cord clamping enables an increased volemia due to blood transfer to the newborn from the placenta. AIM: To assess whether clamping time can affect limb perfusion and heart hemodynamics in a group of 22 healthy term newborn infants. STUDY DESIGN: A case-control study. SUBJECTS: Eleven early-clamped (at 30 s) vaginally-delivered newborn infants were compared with eleven late-clamped (at 4 min) newborns. OUTCOME MEASURES: The two groups were studied using near-infrared spectroscopy and M-mode echocardiography. RESULTS: Late cord clamping coincided with a higher hematocrit (median 62% versus 54%) and hemoglobin concentration (median 17.2 versus 15 g/dL), whilst there were no changes in bilirubin level. Echocardiography showed a larger end-diastolic left ventricle diameter (1.7 cm median value versus 1.5) coupled with unvaried shortening and ejection fraction values. There were no changes in calf blood flow, oxygen delivery, oxygen consumption or fractional oxygen extraction calculated from the NIRS measurements, or in foot perfusion index. CONCLUSIONS: Our results demonstrated that late cord clamping coincides with an increased placental transfusion, expressed by higher hematocrit and hemoglobin values, and larger left ventricle diameter at the end of the diastole, with no changes in peripheral perfusion or oxygen metabolism.     

Transthoracic Impedance: IV. Studies of the Infant During the First Two Hours of Life

The initial functional adaptation has been studied with the transthoracic impedance measuring technique in infants from 15 minutes to two hours of life. The series consists of 20 newborns with early and 20 with late clamping of the umbilical cord.
All infants showed a marked fall in basic impedance IZ, I between 15 and 30 minutes of age. From 45 to 75 minutes jZ, I was virtually unchanged, a t a level somewhat lower for the late-clamped group. During the second hour a rising IZ,/ was noted in the same group.
With the aid of a mathematical formula an extrapolation backwards from 15 minutes to the time of birth was made for lZol. The results obtained directly and after the extrapolation are discussed together with previous known facts about the adaptation process in animals and infants.
Main factors influencing IZ, I are air filling of the lungs, pulmonary blood volume and pulmonary interstitial fluid volume. The dynam-ic interplay between these variables during the first hours is discussed.
The results suggest a pronounced increase of pulmonary blood volume and pulmonary interstitial fluid volume during the first half hour of life, simultaneously with the establish-ment of a functional residual capacity of air in the lungs.
That infants with late clamping of the umbilical cord fall to a lower level of IZ,/ for the time period from 45 to 75 minutes is inter-preted as reflecting a larger pulmonary blood volume in combination with a smaller func-tional residual capacity as compared with the early-clamped group. A rise in IZ, I for late-clamped infants during the second hour of life points in the direction of an approximation between the two groups as pulmonary fluid and blood decreases and functional residual capacity increases in the late-clamped group. No significant changes in transthoracic impedance were found in a control group of newborns past the post-natal period of early adaptation to extra-uterine life.     

Neonatal hyperviscosity: I. Incidence.

Capillary hematocrits were performed on 790 infants during the first four hours after birth. These infants were delivered between August 8 and December 7, 1974, at the University of Colorado Medical Center, which is at an altitude of 1,061 m above sea level. When the capillary hematocrit was 7% or greater, venous hematocrit and blood viscosity were determined. Capillary hematocrits obtained from warmed heels in the first hour after birth were spuriously high and not consistently related to venous hematocrit. Venous polycythemia, defined as a hematocrit of 65% or greater, occurred in 4% of the newborn population. Hyperviscosity (greater than 2 SD above the mean for newborns) occurred in 5% of the newborn infants. At a venous hematocrit of 65% or greater, hyperviscosity was predictable, but some infants with venous hematocrits between 60% and 64% also had hyperviscosity of the blood. The incidence of polycythemia and hyperviscosity was further related to birth weight and gestational age. The infants who were small for gestational age were at highest risk of polycythemia and hyperviscosity, followed by infants who were large for gestational age. However, the greatest number of infants with hyperviscosity were term appropriate for gestational age. Preterm infants with gestational ages of less than 34 weeks were not affected.     

THE INFLUENCE OF DIFFERENT ENVIRONMENTAL TEMPERATURES ON PULMONARY GAS EXCHANGE and BLOOD GAS CHANGES AFTER BIRTH

Abstract. Tunell, R. (Department of Paediatrics, Karolinska Sjukhuset, Stockholm, Sweden). The influence of different environmental temperatures on pulmonary gas exchange and blood gas changes after birth. Acta Paediatr Scand, 64:57, 1975.–The oxygen uptake (V_o2) and respiratory exchange ratio (R) was determined during the first 20 min and at one and at 2 hours after birth in 16 healthy full-term newborn infants studied in different environmental temperatures. Arterial blood gases and acid-base balance were determined on repeated blood samples from the abdominal aorta. The infants were grouped in a “warm” group (n= 10) where efforts were made to avoid cooling after birth, and a “cold” group (n=6) where a decrease in rectal temperature to a mean value of 35.4^oC at 2 hours occurred. Irrespective of environmental temperature, V_o2 was approximately 10 ml/kg min during the first 8 min after birth, thereafter decreasing to about 6–7 ml/kg min. During the first 8 min the main increase in P_a02 occurred and about 2 ml/kg min of the V₀ was accounted for by changes in oxygen stores after birth. At 16–20 min and at 60 min after birth a negative relationship was found between V_o2 and P_ao2 During the period 8–120 min after birth a close relationship was found between V_o2 and the degree of muscular activity. Within 4–16 min after birth, R values above 1.0 were regularly found simultaneously with the main decrease in P_aco2. In infants kept “cold” a tendency to hyperventilate was found, probably elicited by cold stimuli. The rapid drop in deep body temperature regularly seen after birth could thus not be explained by a limited ability to increase pulmonary gas exchange. A high degree of evaporative heat loss, a relatively low “basal” metabolic rate and a limited response in “non-shivering thermogenesis” seem to be the main reasons for the heat loss after birth.     

Renal Function and Blood Volume in Newborn Infant Related to Placental Transfusion

Inulin and PAH clearances, urine flow, filtration fraction, electrolyte excretion and blood volume studies were performed on 43 term vaginally delivered female normal infants during the first 12 hours of life and 26 during the 2nd to the 5th day of age. The umbilical cords of 22 infants were clamped within 5 seconds after birth and in 47 infants, the cords were clamped after their arterial pulsation had stopped. Compared with the late clamped infants, the blood volume, red cell volume and venous hematocrit were lower in the early clamped infants during the first five days of life. The urine flow, glomerular filtration rate (GFR), PAH clearance and effective renal blood flow were also lower in the early clamped infants during the first 12 hours of life, presumably due to the lower blood volume and blood pressures. At 2-5 days of age, the urine flow, GFR, PAH clearance and effective renal blood flow were the same in both groups of infants in spite of persistent difference in blood volume. The early clamped infants apparently achieved renal adaptation through means other than blood volume compensation. Data on electrolyte metabolism suggest that the late clamped infants filtered and reabsorbed larger amount of sodium than the early clamped infants during the first 6 hours of life, accompanied by a greater urine flow. These findings were appropriately achieved by the kidney in the process of body fluid regulation in response to the vascular distension and fluid transudation resulting from placental blood transfusion at birth.     

METABOLIC EFFECTS OF OBSTETRIC REGIONAL ANALGESIA AND OF ASPHYXIA IN THE NEWBORN INFANT DURING THE FIRST TWO HOURS AFTER BIRTH: III. Adjustment of Arterial Blood Gases and Acid-base Balance

Abstract. S. Swanström and L.-E. Bratteby. (Perinatal Research Unit, Department of Paediatrics and Unit of Paediatric Physiology, Department of Clinical Physiology, University Hospital, Uppsala, Sweden). Metabolic effects of obstetric regional analgesia and of asphyxia in the newborn infant during the first two hours after birth. III. Adjustment of arterial blood gases and acid-base balance. Acta Paediatr Scand, 70: 811, 1981.-Effects of obstetric regional analgesia and of asphyxia on the arterial blood gases and acid-base balance in the first two hours after birth were investigated in 85 newborn infants divided into a control group, an asphyxia group and a continuous epidural, an intermittent epidural and a paracer-vical + pudendal block group. Lidocaine was the drug used in the analgesia groups. In the asphyxia group the metabolic acidosis decreased and pH was normalized to the level of the control group between 10 and 30 min after birth. During this period in the asphyxia group Pa_o2 was higher than and Pa_co2 similar to the corresponding control values. Compared with the control group, in the regional analgesia groups the metabolic acidosis tended to be less extensive and Pa_o2 higher, whereas Pa_co2 was similar. A lower packed red cell volume in the asphyxia and in the regional analgesia groups, probably due to differences in placental transfusion, may have had influence on the results. Within the regional analgesia groups infants with hyperglycemia showed signs of an increased metabolic acidosis while infants with hypoglycemia had low base deficit and lactate values supporting the assumtion that neonatal blood glucose concentration may reflect perinatal distress.     

A study of blood glucose level in the newborn—From birth to 7 days

Summary Blood sugar values have been determined by the method of Sharmaet al. in three groups of newborns viz., normal, small for date and preterm. The values in small for date babies were significantly different from normal ones. The small for date babies showed the lowest mean blood glucose value of 32 mg percent at age 13 to 18 hours and preterm newborns also had a mean value of 31.8 mg percent at the same age. The rate of fall of blood glucose was faster in small for date neonates. Males had slightly less blood glucose values than females and birth weight as such had no significant effect on blood glucose value. Preterm babies had a group mean value of 39.8 mg percent as compared to 47.2 mg percent in term babies. The mean blood glucose value was higher by a factor of 1.6 mg percent in femoral vein blood as compared to a heel prick sample. From the Department of Paediatrics and Biochemistry, Medical College, Kanpur.     

极低出生体重儿生后一天酸碱平衡状态及其影响因素

目的 探讨极低出生体重儿(VLBWI)生后1 d内酸碱改变及其影响因素。方法 回顾性分析66例VLBWI生后1 d的酸碱改变情况.按不同酸碱紊乱类型及有无并发症进行分组分析酸碱改变情况及其主要影响因素。结果①酸碱紊乱类型以呼吸性酸中毒+代谢性酸中毒(33.3％)或单纯呼吸性酸中毒(30.3％)为主;②合并肺疾病组的血气分析结果与肺外合并症组之间存在明显差异(P<0.05),窒息组代谢性酸中毒发生率为68.4％;③无并发症组中不同胎龄、不同出生体重、不同时龄的血气结果比较均无统计学差异(P>0.05)。结论极低出生体重儿生后1 d酸碱改变类型以呼吸性酸中毒+代谢性酸中毒及单纯呼吸性酸中毒为主;主要受肺内合并症及出生窒息影响,与胎龄、出生体重及时龄关系不明显;对重症酸碱平衡紊乱早期进行诊断与治疗效果较为满意。     

Use of oxygen therapy during labour and acid-base status in the newborn

The effect of supplemental maternal oxygen therapy on acid-base status has for years been a subject of controversies. There is still no general agreement about oxygen administration in pregnancy or in labour. Many clinicians believe that in normal pregnancy maternal oxygen treatment has merely negligible, if any, influence on the foetus. Maternal oxygen therapy has frequently been suggested when oxygen supply to the foetus was insufficient, viz. in antepartum or intrapartum hypoxia. The aim of this study was to determine whether a brief maternal hyperoxygenation during caesarean section or during the second stage of normal delivery affects cord blood acid-base status measured at birth. Patients with uneventful term pregnancy admitted to the delivery room in spontaneous labour or indicated for elective caesarean section were matched and prospectively ascribed to the control or treatment group. The latter received 60% oxygen for ca. 10 min at 15 L/min by a face mask. We studied 41 normal term infants of healthy mothers (24 from caesarean sections, the remaining 17 delivered vaginally). The control group consisted of normal newborns chosen according to the same criteria except that their mothers had no oxygen supplementation. Immediately after delivery, umbilical cord paired blood samples were drawn. Arterial and venous specimens were analysed for blood gases and acid-base balance parameters. Statistical analysis assisted by computer software was performed using Mann-Whitney U test. A p value < 0.05 was considered significant. All tested parameters related to the acid-base status and blood gases were similar in the treatment and control groups. Concluding, a short period of maternal hyperoxygenation either in the second stage of vaginal spontaneous delivery or during caesarean section did not affect umbilical cord blood acid-base status measured at birth.     

Comparison of Two Phototherapy Methods (Prophylactic vs Therapeutic) for Management of Hyperbilirubinemia in Very Low Birth Weight Newborns

Objective

Preterm and low birth weight (LBW) infants are at greater risk of developing bilirubin-associated brain damage compared with term infants. Certainly, phototherapy, if used appropriately, is capable of controlling the bilirubin levels in LBW infants; but there is not a unique phototherapy treatment strategy in LBW infants. This study was designed to compare the prophylactic phototherapy and late treatment of jaundiced newborns weighing 1000-1500 grams.

Methods

Sixty newborns with birth weight 1000–1500 g were studied. They were divided into two groups: the “Prophylactic” group, in which phototherapy started within six hours after birth and continued for at least 96 hours, and the "Treatment" group, which received phototherapy when indicated according to birth weight and suspended when bilirubin level fell below 50% of bilirubin level for blood exchange. Mean value of daily transcutaneous bilirubin (TCB), duration of phototherapy, the need for blood exchange, and the highest TCB value in both groups were analyzed.

Findings

In the prophylactic group, the highest daily mean rate of TCB was 7.71±1.84 mg/dl, which happened on the third day. In the treatment group, it was 8.74±1.72 mg/dl on the fourth day after birth. The TCB values in prophylactic group were significantly less than those of the treatment group only on the fourth and fifth days after birth (P<0.001). Although the median duration of phototherapy in the treatment group was shorter than that of the prophylactic group (137.60±57.39 vs 168.71±88.01 hours, respectively), this difference was not statistically significant. Only one neonate needed blood exchange in the treatment group.

Conclusion

The prophylactic phototherapy treatment for babies weighing 1000–1500 g significantly decreases bilirubin levels on the fourth and fifth days after birth but the clinical course of hyperbilirubinemia does not alter in LBW infant, as indicated by the non-significant change in the duration of phototherapy.     

Serum growth-promoting activity measured as [3H]thymidine incorporation into human activated lymphocytes and serum transferrin levels in newborns and mothers

Serum growth-promoting activity measured as [3H]thymidine incorporation into human activated lymphocytes and serum transferrin levels were measured during the perinatal period in newborns and mothers. Both thymidine activity (TA) and transferrin levels were significantly increased at the time of delivery in mothers compared to control women, and there was a progressive return to control levels in the first 5 postpartum days. A significant correlation was found between TA and placental weight. In the newborns, TA was low in cord blood after vaginal delivery but not in the cord blood from babies born by cesarean section. In premature newborns, TA was lower than in full term newborns. In all newborns during the first 24 postnatal hours, there was an increase in TA with levels rising above adult control values: levels in cord blood were positively correlated with birth weight but not with thymidine activity. These data afford complementary insights into the humoral controls of growth in newborn infants.     

Neonatal hypothyroxinemia

Serum thyroxine (T₄) and thyroid stimulating hormone (TSH) were estimated in 25 well term and 30 well preterm neonates in blood samples collected from cord blood and subsequently at 24 hours and 72 hours of age. Cord blood serum T₄ concentration was higher in term than preterm babies. Reverse pattern was observed for serum TSH concentration. Both serum T₄ and TSH showed a rise at 24 hours and a fall at 72 hours of age. None of the neonates had primary hypothyroidism. The incidence of transient hypothyraxinemia in term babies was 4% at birth, nil at 24 hours, and 16% at 72 hours of age. The corresponding values for preterm babies were 63.3%, 3.3% and 23.3%.     

Pituitary-thyroid responsiveness to thyrotropin-releasing hormone in preterm and small-for-gestational age newborns.

A dose of 40 microgram TRH was injected intravenously in 12 preterm (PT) and 15 small-for-gestational age (SGA) babies (with advanced gestational ages) between 5 and 167 hours after birth. Serum-thyrotropin (TSH) was measured prior to and 30 and 180 min after TRH; serum-thyroxine (T4) and serum-triiodothyronine (T3) were measured prior to and 180 min after TRH. The percentage increase in serum-TSH in PT and SGA babies was comparable to that of fullterm newborns. The serum-TSH 30 min after TRH in SGA newborns was significantly correlated to basal TSH values, such a correlation could not be shown in the preterms. One SGA and four PT babies had a repeat TRH-test performed later in infancy: In all but one PT with a gestational age of 27 weeks the TSH rise was lower than in the neonatal period. The thyroid hormone responses after TRH were similar in the two groups of babies. The percentage increase above basal levels were: Median serum-T3 increase about 46% and median serum-T4 increase about 14%. It is concluded that in low-birth-weight newborn babies the pituitary TSH response to exogenous TRH was like that detected in fullterm newborns and more pronounced that later in infancy. The effect of endogenous TSH as measured by thyroid hormone increases was of the same magnitude as observed in fullterms and in adults.     

Plasma hypoxanthine and xanthine levels in the early newborn period in problem-free preterm babies and those with idiopathic respiratory distress syndrome

The use of hypoxanthine measurements for quantitative monitoring of intrauterine asphyxia is generally accepted. A high level in blood or in CSF is a consequence of tissue hypoxia. Hypoxanthine and xanthine were measured by selective high pressure liquid chromatography in mature newborns, in healthy, symptom-free preterm babies, and in preterm babies affected by idiopathic respiratory distress syndrome. The measurements were carried out from peripheral venous blood within three hours after birth and at the age of 48-72 hours. In mature newborns the mean hypoxanthine level was 11.10 mumol/l in the early determinations, and 8.45 mumol/l in the second set of measurements. In unaffected prematures there were significantly higher levels, and the highest values (44.22 +/- 15.13 mumol/l) were encountered in premature babies subsequently dying of severe hypoxia. Xanthine showed a similar course. In addition to establishing normal values for prematures we desired to clarify the changes in the levels of purine metabolites during idiopathic respiratory distress and their prognostic value. Hypoxanthine and xanthine levels were found to be informative in postnatal hypoxia, especially together with other parameters.     

PITUITARY-THYROID RESPONSIVENESS TO THYROTROPIN-RELEASING HORMONE IN PRETERM AND SMALL-FOR-GESTATIONAL AGE NEWBORNS

Abstract. A dose of 40 μg TRH was injected intravenously in 12 preterm (PT) and 15 small-for-gestational age (SGA) babies (with advanced gestational ages) between 5 and 167 hours after birth. Serum-thyrotropin (TSH) was measured prior to and 30 and 180 min after TRH; serum-thyroxine (T₄) and serum-triiodothyronine (T₃) were measured prior to and 180 min after TRH. The percentage increase in serum-TSH in PT and SGA babies was comparable to that of fullterm newborns. The serum-TSH 30 min after TRH in SGA newborns was significantly correlated to basal TSH values, such a correlation could not be shown in the preterms. One SGA and four PT babies had a repeat TRH-test performed later in infancy: In all but one PT with a gestational age of 27 weeks the TSH rise was lower than in the neonatal period. The thyroid hormone responses after TRH were similar in the two groups of babies. The percentage increase above basal levels were: Median serum-T₃ increase about 46% and median serum-T₄ increase about 14%. It is concluded that in low-birth-weight newborn babies the pituitary TSH response to exogenous TRH was like that detected in fullterm newborns and more pronounced than later in infancy. The effect of endogenous TSH as measured by thyroid hormone increases was of the same magnitude as observed in fullterms and in adults.     

Blood gas values in clamped and unclamped umbilical cord at birth

AimTo determine the reliability of the cord blood gas analysis on the unclamped cord compared to the standard technique of sampling on double clamped cord.Study designProspective observational study conducted on 46 singleton neonates vaginally delivered at term. Matched pairs of umbilical artery and vein blood samples were collected from unclamped cord within 90 s after birth and from the same cord after clamping, with the clamping occurring immediately after the first blood collection. A blood gas analysis was performed on each collected sample.Outcome measuresArterial and venous blood samples were analyzed for pH, PO₂, pCO₂, SaO₂, hemoglobin concentration (ctHb) and base excess (BE). The values were compared between the two groups (clamped vs unclamped) using a Wilcoxon test.ResultsNo significant difference was found in pH, PO₂, pCO₂, SaO₂ and ctHb values on arterial blood between unclamped and clamped cord. The only significant difference was related to BE (p < 0.001). For the venous blood, the values of pH, PO₂, pCO₂ were comparable between unclamped and clamped cord, while the values of SaO₂, ctHb and BE were significantly different (p < 0.05).ConclusionNo significant difference was found in almost all the arterial blood gas parameters and in the main venous blood gas parameters between unclamped and clamped cord. Sampling of cord blood for gas analysis may be performed on the unclamped cord right after birth without reducing the accuracy of the analysis.     

Untersuchungen zur postpartalen Süre-Basensituation Frühgeborener

Summary The influence of postnatal acid-base disregulations on the postnatal adaption of premature infants is evaluated. In 1385 serial measurements the pH, base-excess and pCO₂ of arterialized capillary blood were studied by use of the Astrup micromethod. From 50 normal prematures data were collected during the first 10, on the 15th and 30th day of life. In the absence of pulmonary complications even low weight prematures are able to compensate the metabolic component of the acidosis. Furthermore the influence of birthweight and abnormal delivery on the postnatal acid-base balance is reported. A severe disturbance of postnatal homeotasis can be assumed, if, two hours after birth, the pH in capillary blood is below 7,20, the pCO₂ above 80 Torr, and the baseexcess below — 15meq/l.

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Auszugsweise vorgetragen auf der 3. Jahrestagung der Österreichischen Gesellschaft für Kinderheilkunde, Wien, 8.–10. 10. 1965.