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Biomedical subjects

O Linderkamp

Publications and source records attributed to O Linderkamp.

At least 91 records · Page 5Linked to original sources
PubMed1995

Effect of Leboyer childbirth on cardiac output, cerebral and gastrointestinal blood flow velocities in full-term neonates.

The Leboyer birth method requires that the newly born infant is placed on the mother's abdomen and the cord is clamped when it stops pulsating. This investigation was done to study the effect of Leboyer childbirth on neonatal circulation during the first 5 days after birth. Hematocrit, blood viscosity, left and right ventricular output, and cerebral blood flow velocities in the arteria carotis interna, arteria cerebri anterior, and truncus coeliacus were studied in 15 full-term neonates with early (less than 10 seconds) cord clamping and 15 full-term neonates delivered according to Leboyer (cord clamping after 3 minutes) on day 1 (2 to 4 hours after birth) and day 5. The fetal placental blood volume decreased from 42 +/- 8 mL/kg (mean +/- SD) of neonatal body weight after early cord clamping to 19 +/- 7 mL/kg after Leboyer delivery. Neonatal blood volume, calculated from the fetal placental blood volume, was 32% higher in the Leboyer group compared with the early cord-clamped infants. In the infants with early cord clamping, hematocrit, and blood viscosity did not change significantly during the first 5 days. After Leboyer birth, the hematocrit rose from 0.51 +/- 0.05 in cord blood to 0.62 +/- 0.06 at 2 to 4 hours of age, thereby increasing blood viscosity by 32%. Stroke volume, heart rate, cardiac output, left-to-right shunt across the ductus arteriosus, and blood flow velocity in the truncus coeliacus were similar in both groups and did not change during the first 5 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1995

Pitfalls in respiratory monitoring of premature infants during kangaroo care.

The reliability of respiratory monitoring, using either chest or back electrodes, was studied in 13 preterm infants during kangaroo care (infant-parent skin to skin contact). In three out of four infants with chest electrodes both infant and parental respiration were clearly visible on pneumograms. In these infants apnoeic pauses were not registered because parental respiration was recorded as infant breathing. Bradycardia and oxygen saturation were, however, properly registered. In infants with electrodes placed on the back infant respiration was less superimposed by parental breathing. However, even in some of these infants parental respiration was visible in the pneumograms. It is concluded that during kangaroo care the electrodes should be placed on the back and monitoring should always include heart rate and oxygen saturation.

Apnea↗
PubMed1995

Effect of blood transfusion on cardiorespiratory abnormalities in preterm infants.

The effects of red blood cell transfusion on the incidences of apnoea, bradycardia, tachycardia and oxygen desaturation over periods of 72 hours before and after transfusion were assessed in 25 infants with a gestational age of < or = 32 weeks (mean (SEM) 29.2 (0.4) weeks, birthweight 1170 (73) g; postnatal age at transfusion 39 (4) days). During transfusion haemoglobin rose from 78 (2) g/l to 117 (2) g/l. Significant decreases were observed in daily frequencies of apnoeas longer than 15 seconds (median from 2.7 to 0.9 events a day), tachycardias of more than 200 beats per minute (from 34 to 25 events per day), bradycardias below 100 beats per minute (from 65 to 12 events per day) and 80 beats per minute (from 8.4 to 3.3 events per day). Oxygen saturation improved in 20 of the infants. Transfusion improves cardiorespiration in preterm infants for several days.

Apnea↗
PubMed1995

Lipid A binding to neonatal and adult red blood cells.

Lipid A is responsible for the endotoxic activities of gram-negative bacteria. Binding of lipid A (50 micrograms/ml) to RBC was studied using a passive hemolysis test. RBC from adults, cord and venous RBC from full-term infants and RBC from preterm infants were studied. Lipid A sensitized RBC were hemolysed with anti-lipid A and guinea pig complement. Hemolysis was expressed as hemoglobin concentration (absorbance at 546 nm) in the supernatant after centrifugation. 50 micrograms/ml lipid A did not increase spontaneous hemolysis (< 3%) after 60 min of incubation in any of the four groups. The passive hemolysis test did not result in additional hemolysis (5%) of umbilical cord RBC. RBC of preterm infants showed a significant increase in hemolysis (24%) after 60 min of incubation. In RBC of full-term neonates, increased hemolysis (14 and 46%) was detected after 30 and 60 min of incubation. Adult RBC hemolysed stronger (26 and 64%) after 30 and 60 min than neonatal RBC. We conclude that lipid A binds less to neonatal RBC compared to adults.

Adult↗
PubMed1994

A controlled clinical trial of light and retinopathy of prematurity.

Bright continuous light has been implicated in the pathogenesis of retinopathy of prematurity. To investigate the influence of light on the incidence and severity of retinopathy of prematurity, we enrolled 127 preterm infants (birth weight < or = 1,500 g; gestational age < or = 32 weeks) in a controlled clinical study. Randomization was done separately for three birth-weight groups (< 1,000 g; 1,000 to 1,249 g; 1,250 to 1,500 g). The babies' eyes were patched all day and night from birth to a gestational age of 35 weeks. The infants in the control group were exposed to cycled lighting conditions (that is, reduced light level during the night). Of 62 infants with patched eyes, 26 (42%) developed retinopathy of prematurity. In the control group, 25 of 65 infants (39%) showed retinopathy of prematurity (P = .596). There were also no statistically significant differences in the incidences of retinopathy of prematurity in the birth-weight subgroups or in the severity of retinopathy of prematurity. Thus, patching of the eyes from birth to 35 weeks of postconceptional age does not decrease the risk of retinopathy of prematurity in preterm infants when compared to a control group exposed to cycled lighting conditions.

Female↗
PubMed1994

The effect of epoetin beta (recombinant human erythropoietin) on the need for transfusion in very-low-birth-weight infants. European Multicentre Erythropoietin Study Group.

BACKGROUND: Anemia of prematurity is characterized by low reticulocyte counts and inadequate erythropoietin response, for which many very-low-birth-weight infants receive multiple blood transfusions. We investigated whether early treatment of such infants with recombinant human erythropoietin would reduce their need for transfusions. METHODS: We performed a controlled, blinded trial in 241 infants with very low birth weights at 12 centers in six European countries. When three days old, the infants were randomly assigned either to the epoetin group or to the control group. Those in the epoetin group received 250 IU of epoetin beta per kilogram of body weight subcutaneously three times a week from day 3 to day 42 (for a total of 17 doses); those in the control group did not receive this drug. Infants in both groups received oral iron (2 mg per day) from day 14 onward. RESULTS: The control infants needed a mean of 1.25 transfusions each, as compared with 0.87 transfusion for epoetin-treated infants (P = 0.013). The median cumulative volume of blood transfused per kilogram per day was 0.41 ml in the control group (first quartile, 0 ml; third quartile, 0.8 ml) and 0.09 ml in the epoetin group (first quartile, 0 ml; third quartile, 0.8 ml) (P = 0.044). The rate of success, defined as an absence of need for transfusions and a hematocrit that never fell below 32 percent, was 4.1 percent in the control group and 27.5 percent in the epoetin group (P = 0.008). Epoetin was most beneficial in boys with birth weights of 1200 g or more and a base-line hematocrit of 48 percent or more. No toxic effects were observed in the epoetin group; as compared with the control group, the epoetin group had an increased incidence of septicemia (14 vs. 7 episodes, P not significant) and reduced weight gain (520 vs. 571 g, P = 0.02). CONCLUSIONS: Infants with very low birth weights have less need of transfusions if given epoetin beta during the first six weeks of life (250 IU per kilogram three times a week). We recommend early epoetin treatment for all such infants, but further studies of nutrition and iron supplementation during treatment are needed.

Anemia, Neonatal↗
PubMed1994

Cardiac output and cerebral blood flow velocity in small for gestational age infants during the first 5 days after birth.

Small for gestational age (SGA) infants are at an increased risk of neurologic handicap. Cardiac output and cerebral blood flow velocity (CBFV) were measured by pulsed Doppler sonography in 15 SGA infants and in 15 appropriate for gestational age (AGA) infants on days 1 and 5 after birth. The gestational age of both groups ranged from 32 to 40 weeks and averaged 37 weeks. Cardiac output was higher in the SGA infants than in the AGA infants on day 1 (314 +/- 62 vs. 275 +/- 36 ml/min/kg; P < 0.05), but similar in the SGA and AGA infants on day 5 (319 +/- 66 vs. 318 +/- 53 ml/min/kg). On day 1, both haematocrit (0.53 +/- 0.04 vs. 0.49 +/- 0.04 l/l; P < 0.05) and systemic red blood cell transport (169 +/- 35 vs. 136 +/- 24 ml/kg/min; P < 0.01) were higher in the SGA infants than in the AGA infants. Systemic red cell flow increased in the AGA infants from day 1 to day 5 (157 +/- 27 ml/min/kg; P < 0.05), but not in the SGA infants (166 +/- 39 ml/kg/min). Mean cerebral blood flow velocity (CBFV) was higher in the AGA infants than in the SGA infants on both days (P < 0.05). However, cerebral red blood cell transport (CBFV x haematocrit) was similar in both groups. We conclude that on day 1, systemic red blood cell transport is higher in SGA infants than in AGA infants due to increased cardiac output and haematocrit.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1994

Reactive hyperemia of skin microcirculation in septic neonates.

Reactive hyperemia after 1 min of arterial occlusion was studied in back, thigh and heel skin of 40 preterm and full-term neonates using laser Doppler flowmetry. Twelve infants had clinical signs of septicemia, but normal laboratory tests at the time of fluxmetry. However, CRP, leukocyte count and the ratio of immature to total neutrophils increased during the following days and septicemia was confirmed by positive blood cultures (septic group). Seven neonates with clinical signs of septicemia had developed neither positive blood cultures nor laboratory signs (non-septic group). Fifteen were healthy neonates. In the septic neonates, time to reach maximal hyperemia, maximum post-occlusive hyperemia and recovery time of skin perfusion were increased significantly in back and thigh skin and the heal skin temperature was decreased when compared to healthy neonates. Healthy and non-septic neonates showed no significant difference in any of the parameters. We conclude that altered reactive hyperemia in the skin may be an earlier sign of neonatal septicemia than laboratory tests.

Humans↗
PubMed1994

Effects of red cell transfusion on cardiac output and blood flow velocities in cerebral and gastrointestinal arteries in premature infants.

Anaemia may increase the risk of tissue hypoxia in preterm infants. The effect of transfusion on circulation was studied in 33 preterm infants with a mean (SD) gestational age of 29 (5) weeks (range 26-34), birth weight 1153 (390) g (range 520-1840), and postnatal age of 48 (21) days (range 19-100). Packed cell volume, blood viscosity (capillary viscometer), cardiac output, and cerebral blood flow velocities in the internal carotid artery, anterior cerebral artery, and coeliac trunk (Doppler ultrasound) were determined before and after transfusion of 10 ml/kg of packed red blood cells. Transfusion increased packed cell volume from a mean (SD) 0.27 (0.45) to 0.37 (0.48). Mean arterial blood pressure did not change while heart rate decreased significantly from 161 (14) l/min to 149 (12). Cardiac output decreased from 367 (93) ml/kg/min to 311 (74) due to decrease in stroke volume from 2.28 (0.57) ml/kg to 2.14 (0.46) and in heart rate. There was a significant increase in systemic red cell transport (cardiac output times packed cell volume) by 17%, systemic flow resistance (blood pressure to cardiac output ratio) by 23%, and blood viscosity by 33%. Vascular hindrance (flow resistance to blood viscosity ratio) did not change significantly, thereby suggesting that neither vasoconstriction nor vasodilation occurred with transfusion. After transfusion blood flow velocities decreased significantly in the anterior cerebral artery by 23%, in the internal carotid artery by 8%, and in the coeliac trunk by 12%. Red cell transport estimated as products of blood flow velocities times packed cell volume increased significantly by 25% in the internal carotid artery and by 21% in the coeliac trunk. These results indicate that red cell transfusion improved systemic oxygen transport as well as oxygen transport in the internal carotid artery and coeliac trunk.

Blood Flow Velocity↗
PubMed1994

Effects of polycythaemia and haemodilution on circulation in neonates.

Haemodilution in nine neonates resulted in significant mean (SEM) decrease of packed cell volume (0.67 (0.01) to 0.55 (0.01)) and increases in cardiac output (250 (16) to 308 (25) ml/min/kg) and blood flow velocities of the internal carotid artery and the coeliac artery (+20%). However, red cell flows in the aorta, carotid and coeliac arteries did not change during haemodilution, thereby indicating that haemodilution did not improve oxygen transport.

Blood Flow Velocity↗
PubMed1994

Blood transfusion in late anemia of prematurity: effect on oxygen consumption, heart rate, and weight gain in otherwise healthy infants.

BACKGROUND: In premature infants there is no universally accepted definition of anemia requiring transfusion. We designed the present investigation to study the effects of red blood cell transfusion (based on simple transfusion rules) on weight gain, energy metabolism, and heart rate in otherwise healthy preterm infants. PATIENTS AND METHODS: We measured oxygen consumption (VO2), respiratory quotient (RQ) and energy expenditure (EE) by 4-hour indirect calorimetry, and assessed weight gain over 7 days and heart rate in 12 infants with late anemia of prematurity before and after red blood cell transfusion (10 ml/kg). At the time of transfusion, postmenstrual age was 38 +/- 1 weeks (mean +/- SEM), body weight 2.14 +/- 0.13 kg, and hemoglobin concentration 7.7 +/- 0.3 g/dl (range: 5.5-9.2). RESULTS: Red blood cell transfusion increased the hemoglobin concentration by 3.8 +/- 0.5 g/dl, but had no significant effect on weight gain (15.4 +/- 2.4 vs. 13.8 +/- 1.8 g/kg/day), VO2 (8.7 +/- 0.3 vs. 8.7 +/- 0.3 ml/kg/min), minimal VO2 (7.2 +/- 0.3 vs. 7.7 +/- 0.4 ml/kg/min), RQ (0.96 +/- 0.02 vs. 0.95 +/- 0.02), EE (50 +/- 2 vs. 51 +/- 2 kcal/kg/day), and heart rate (160 +/- 3 vs. 158 +/- 3 min-1). CONCLUSION: We conclude that oxygen supply and energy metabolism were not compromised in the anemic preterm infants at the time of red blood cell transfusion.

Anemia, Neonatal↗
PubMed1993

The effect of Leboyer delivery on blood viscosity and other hemorheologic parameters in term neonates.

OBJECTIVE: This study was done to compare postnatal alterations in blood viscosity, hematocrit value, plasma viscosity, red blood cell aggregation, and red blood cell deformability in term neonates undergoing both early umbilical cord clamping and delivery according to the Leboyer method. STUDY DESIGN: The umbilical cords of 15 healthy, term infants were clamped within 10 seconds of birth (early cord clamping), and 15 infants delivered according to the Leboyer method were placed on the mother's abdomen, and the umbilical cords were clamped 3 minutes after birth. Hemorheologic parameters were studied in umbilical cord blood at 2 hours, 24 hours, and 5 days from the time of delivery. RESULTS: The residual fetal placental blood volume decreased from 45 +/- 8 ml/kg (x +/- SD) after early cord clamping to 25 +/- 5 ml/kg after delivery by the Leboyer method. After Leboyer-method delivery, the hematocrit value rose from 48% +/- 5% at birth to 58% +/- 6% 2 hours after delivery, 56% +/- 7% at 24 hours, and 54% +/- 8% after 5 days. Blood viscosity in the Leboyer-method group increased by 32% within the first 2 hours but did not change significantly during the following 5 days. Plasma viscosity, red blood cell aggregation, and red blood cell deformability were not affected by the mode of cord clamping. CONCLUSIONS: Delivery by the Leboyer method leads to a significant increase in blood viscosity as a result of increasing hematocrit value, whereas other hemorheologic parameters are similar to those of infants with early cord clamping.

Blood Viscosity↗
PubMed1993

Age dependency of red blood cell deformability and density: studies in transient erythroblastopenia of childhood.

Several investigators have demonstrated that red blood cell (RBC) deformability decreases progressively with increasing cell density and proposed that reduction in deformability plays a role in the senescence process of normal RBCs. Transient erythroblastopenia of childhood (TEC) results from temporary cessation of erythropoiesis. Since no new RBCs are produced for some time, the circulating RBCs are relatively old. RBS density (phthalate-oil method) and RBC deformability (RBC elongation in a counter-rotating rheoscope) were studied in seven children with TEC and in 10 control children. The mean values of MCHC, RBC density and RBC deformation were not significantly different between TEC and control children. Compared to controls, the frequency distribution of RBC density in TEC was slightly shifted to higher values. The percentage of RBCs with extremely low densities (< 1.090 g/ml) was 0.9 +/- 1.2% in the patients and 5.6 +/- 2.3% in the controls (P < 0.001). The percentage of RBCs with high density (> 1.106 g/ml) was 6.4 +/- 2.1% in the patients and 4.9 +/- 1.8% in the controls (P > 0.10). The reduction of RBCs with low density in TEC suggests that RBCs with low density are relatively young. Since the percentage of RBCs with high density increased only slightly in TEC, we conclude that only a fraction of dense RBCs is old. In TEC, the frequency distribution of RBC elongation was slightly shifted to lower values. 5% of the RBCs studied in the control children had RBC elongation values above 0.39 (TEC 1.2%) and 5% had elongation values below 0.16 (TEC 6.7%). Thus, only a small fraction of highly deformable RBCs was diminished in TEC. These data suggest that a decrease in deformability is not a significant part of the normal ageing process of human RBCs.

Child, Preschool↗
PubMed1993

Short-term effects of blood transfusion on blood volume and resting peripheral blood flow in preterm infants.

The effects of blood transfusion on cardiac output and blood pressure are variable, but resting peripheral blood flow (RPBF) may be a sensitive indicator of changes in blood volume. The purpose of this investigation was to study the effects of red cell transfusion on blood volume (Evans blue), blood pressure, RPBF in the leg (strain-gauge plethysmography) and blood viscosity (cone-plate viscometer) in preterm infants during the first week after birth. Fourteen infants with mean +/- SD birth weight of 1658 +/- 429 g, gestational age 33 +/- 3 weeks and postnatal age 64 +/- 40 h received 18 +/- 4 ml/kg of packed red cells (red cells 11 +/- 2 ml/kg, plasma 7 +/- 1 ml/kg) because their hematocrit was less than 0.45 l/1. Mean blood volume before transfusion was 88 +/- 15 ml/kg. The increase in blood volume (9 +/- 4 ml/kg) measured 4 to 6 h after transfusion was smaller than the transfused volume (18 +/- 4 ml/kg), due to a shift of plasma to the extravascular space. The plasma shift increased with increasing pretransfusion blood volume (r = 0.70; p = 0.007). Red cell transfusion caused an increase in RPBF by 25% (p < 0.01), whereas systolic blood pressure (BP) increased by only 12%. Peripheral resistance (R = BP/RPBF) decreased by 9% (p < 0.01). Blood viscosity (eta) increased by 21% (p < 0.001) and vascular hindrance (R/eta) decreased by 24% (p < 0.001), indicating vasodilatation of limb arteries. The increase in RPBF and the decrease in hindrance were particularly pronounced in infants with high pretransfusion blood volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1993

Systolic blood pressure and blood volume in preterm infants.

Blood volume and systolic blood pressure (SBP) were measured in 43 preterm infants. Mean (SD) blood volume was 83 (19) ml/kg (range 48-119) and SBP 50 (9) mm Hg (range 34-69), showing a significant overall relationship. Blood volume in infants with SBP > 60 mm Hg (110 (6) ml/kg) was significantly higher than in infants with SBP 40-60 mm Hg (78 (16) ml/kg) and in infants with SBP < 40 mm Hg (75 (10) ml/kg). In conclusion, SBP is of limited value in detecting hypovolaemia in very low birthweight infants.

Blood Pressure↗
PubMed1993

Complement activation in newborn infants with early onset infection.

The complement system is an important element in host defense. Quantitative deficiencies of total hemolytic complement activity and decreased C3 levels were reported in sera from normal neonates. However, little is known about complement activation products in the newborn. In a prospective study, complement activation products were determined in 32 healthy term neonates, in 41 neonates with colonization of their mothers, in 15 colonized neonates, and in 10 neonates with early onset infection. In all newborns, EDTA plasma was obtained within the first 6 h of life. The anaphylatoxin C3a-desArg was determined with a novel ELISA using an MAb reacting with a neoepitope of C3a-desArg. C3bBbP (alternative pathway convertase) and C1rsC1-inactivator (activation product of classical pathway) were measured with double-sandwich ELISA. C3 was determined by radial immunodiffusion. Plasma concentrations of C3a-desArg were similar in healthy term neonates and healthy adults, whereas diminished C3 levels were observed in the newborn infants. There were no significant differences between healthy neonates, neonates with colonized mothers, and colonized neonates. In neonates with infection, a significant elevation of C3a-desArg was found at the onset of the disease, resulting from alternative pathway activation. In contrast, the C1rsC1-inactivator complex showed no significant differences among healthy, colonized, and infected neonates. The anaphylatoxin C3a mediates inflammatory reactions such as vasodilatation and an increase in microvascular permeability and might therefore play an important role in severe neonatal infection.

Complement Activation↗
PubMed1993

Fåhraeus and Fåhreaus-Lindqvist effects for neonatal and adult red blood cell suspensions.

In blood vessels with diameters less than 500 microns, both the hematocrit and viscosity decrease with decreasing tube diameter [Fåhraeus effect (FE) and Fåhraeus-Lindqvist effect (FLE)]. Because both effects may be influenced by red blood cell (RBC) volume and osmolality, the effects of RBC type and suspending medium osmolality (216, 294, and 473 mosmol/kg) on tube hematocrit (HT) and relative viscosity (eta r) in narrow tubes (32 to 145 microns diameter) were studied for 0.40 L/L (40%) hematocrit suspensions of human neonatal and adult RBC in buffer. Osmolality of 473 mosmol/kg caused shrinkage of RBC by 20% so that neonatal RBC assume the volume of adult RBC in isotonic buffer. The FLE and FE were present for both neonatal and adult RBC suspensions regardless of osmolality. The viscosity reduction when going from a 145- to a 32-microns tube was greatest for the hypertonic neonatal and adult RBC: changes were -44% (473 mosmol/kg) and -31% (294 mosmol/kg) for neonatal RBC, and -39% (473 mosmol/kg), -34% (294 mosmol/kg), and -21% (216 mosmol/kg) for adult RBC. The eta r were significantly lower (7% on average) for isotonic neonatal RBC compared with adult cells in 32-microns (p < 0.025), 46-microns, and 146-microns tubes (p < 0.001). In contrast, HT and thus the FE were less affected by RBC type or osmolality (only 13% change over entire range of osmolality and diameter): relative HT values were systematically lower (p < 0.02), and the FE greater, for isotonic neonatal versus adult RBC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗