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Biomedical subjects

H Korvenranta

Publications and source records attributed to H Korvenranta.

At least 19 recordsLinked to original sources
PubMed1992

The size and contractility of the gallbladder in infants.

The size of the gallbladder and the common bile duct as well as the contractility of the gallbladder were measured in infants under the age of 1 year. A total of 43 healthy infants were studied at their routine visit to the well-baby clinic at the ages of 6 weeks, 4 months, 8 months or 12 months. Gallbladder size was measured before and after a test meal. Fasting gallbladder size increased with the age of the infants. However, when the size was corrected for the infant's weight, no age-related variation was found. The contraction index (CI) was determined as a percentage decrement of planimetric gallbladder size from the initial size. The mean CI declined with age from 75% (+/- 27%) (mean (+/- SD)) at the age of 6 weeks to 24% (+/- 28%) at the age of 12 months. Overall CI varied from -44% to 100%. An increase in gallbladder size after the test meal was observed in 4 infants. Gallbladder volumes were also calculated, but two-dimensional measurements were regarded as more accurate in infants. A large variation was found in the size as well as in the contractility of the gallbladder in infants less than 1 year of age.

Common Bile Duct↗
PubMed1992

Information compression in dynamic radiological studies.

The large volumes of digital image data from radiological examinations demand further research and practical solutions in image compression before PACS solutions in large radiological departments are plausible. But another type of compression of image information is also possible, which has, in fact, been somewhat utilized already in analog form, but which has far better possibilities in the digital world. The number of essential images in dynamic X-ray, nuclear medicine, examinations etc. can be greatly reduced. These examinations producing image series are reviewed in terms of compression of information. 3-D displays are very useful in slice imaging, because they provide a means to see easier inside the human body than a number of slice images side by side. We also provide a new method, dynamic pulmonary imaging with digital fluoroscopy, as an example of the digital possibilities to compress a number of images into parametric images, numbers, histograms and curves. These processes also have other positive consequences information is transformed into a more easily perceptible form.

Diagnostic Imaging↗
PubMed1992

Atrial natriuretic peptide in the preterm infant. Lack of correlation with natriuresis and diuresis.

We assessed the relation of atrial natriuretic peptide (ANP) to renal function on postnatal day 2 and day 5 in preterm infants. Plasma ANP concentration was measured by radioimmunoassay in two groups of preterm infants: group 1, gestational age less than 30 weeks, n = 10; and group 2, gestational age 30-34 weeks, n = 11. The identity of the immunoreactivity as ANP-28 was confirmed by HPLC. Plasma ANP was significantly higher in group 1 than in group 2 on day 2 and day 5 (p < 0.01) and ANP concentration decreased by day 5 in both groups (group 1, p < 0.01; group 2, p < 0.02). The results showed no correlation between plasma ANP concentration and urinary sodium excretion or creatinine clearance, which may be due to a blunted renal response to ANP, but other factors may be involved also. We conclude that preterm infants are able to release large amounts of ANP, but a high plasma ANP concentration does not correlate directly with renal regulation of sodium and water balance.

Atrial Natriuretic Factor↗
PubMed1992

Sympathoadrenal activity in preterm infants during the first five days of life.

We measured plasma concentrations of epinephrine (E), norepinephrine (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), and 3,4-dihydroxyphenylglycol (DHPG) as well as urinary concentrations of metanephrine (M), normetanephrine (NM) and 3-methoxy-4-hydroxymandelic acid (MOMA) on day 2 and day 5 in preterm infants; gestational age less than 30 weeks (G less than 30; n = 16) and gestational age 30-34 weeks (G 30-34; n = 19). Concentrations of E (0.00-2.28 nmol/l) and NE (0.6-9.1 nmol/l) in plasma were much lower than those previously reported during preterm and term delivery. The E:NE ratio decreased from 1:10 on day 2 to 1:30 on day 5, and the M:NM ratio decreased from 1:4 on day 2 to 1:8 on day 5, indicating relatively higher catecholamine secretion from the adrenals than from the sympathetic nerve terminals in preterm infants during postnatal adaptation. Plasma concentrations of DOPAC and DHPG were significantly higher in G less than 30 than in G 30-34 (DOPAC, p = 0.0494; DHPG, p = 0.0092), probably relating to a low urinary excretion rate of catecholamine metabolites in infants in G less than 30. Plasma and urinary concentrations of catecholamines and their metabolites varied considerably, and no significant correlations to postnatal events could be demonstrated.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Renal function in preterm infants during the first five days of life: influence of maturation and early colloid treatment.

We measured the influence of maturation and early freshly frozen plasma infusion (FFP) on renal function (day 2 and day 5) in preterm infants in intensive care; they were divided into two groups, those with gestational ages less than 30 weeks (G less than 30) and those with gestational ages of 30-34 weeks (G 30-34). A total of 35 infants was studied. The infants were randomly assigned to one of two treatment groups, one receiving FFP, the other not, yielding four study groups; G less than 30 and no FFP (8 infants), G less than 30 and FFP (8 infants), G 30-34 and no FFP (9 infants) and G 30-34 and FFP (10 infants). The infants in the two FFP groups received FFP 10 ml/kg on days 1-3. FFP did not significantly influence creatinine clearance (CCr) or the urinary sodium excretion rate either in G less than 30 or G 30-34. CCr was significantly lower (p less than 0.001) and fractional urinary sodium excretion significantly higher (p less than 0.002) in infants of G less than 30 than in infants of G 30-34. Infants of G less than 30 had significantly higher plasma potassium concentrations (p less than 0.01) than infants of G 30-34. Despite the low CCr and the high urinary sodium excretion rate, infants of G less than 30 had stable fluid and electrolyte balance.

Aging↗
PubMed1991

Extracellular volume in preterm infants: influence of gestational age and colloids.

We assessed the effect of fresh frozen plasma (FFP) on extracellular volume (ECV) during the first few days of life in two groups of preterm infants, group 1 (gestational age less than 30 weeks) and group 2 (gestational age 30-34 weeks). The infants were randomly assigned to one of two treatment groups, one receiving FFP, the other not; group 1 infants receiving no treatment (n = 8) and group 1 infants receiving FFP (n = 11), and group 2 infants receiving no treatment (n = 9) and group 2 receiving FFP (n = 10). FFP was given at a dose of 10 ml/kg daily during a two-hour period for the first three days of life. ECV was measured on day 1 before FFP was given and on day 4 by the distribution of bromide. There was a significant correlation between birth weight and initial ECV (r = 0.85, P less than 0.001). In group 1 ECV was significantly higher than in group 2 (P less than 0.02). In group 1 receiving no treatment mean weight loss and mean decrease in ECV were equal (84 g/kg and 78 ml/kg, respectively), but no correlation between the two parameters could be found (r = 0.68, P = 0.06). In the other study groups, mean weight loss was higher than mean decrease in ECV, with no correlation between weight loss and change in ECV.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Grading of left-to-right shunting ductus arteriosus in neonates with bedside pulsed Doppler ultrasound.

A nonimaging pulsed Doppler technique was used to grade the magnitude of flow in left-to-right shunting ductus arteriosus. The results were compared with those obtained with a color Doppler flow mapping technique. The correlation between the grading results by these two methods was 0.91 (p less than 0.01). To determine hemodynamic influence of left-to-right shunting ductal flow, simultaneous measurements of Doppler-derived cardiac output were done. Results showed significantly higher cardiac output in infants with grade III shunting than in infants with grade 0 and grade I shunting. The nonimaging pulsed Doppler ultrasound technique used in the present study proved to be a clinically useful and accurate grading system of left-to-right shunting at the ductal level. The simple grading system with nonimaging Doppler is a valuable adjunct to the color Doppler flow mapping technique. It allows a regular evaluation of ductal flow as well as cardiac output.

Cardiac Output↗
PubMed1991

Effect of ventilatory strategy on cardiac output during high frequency jet ventilation.

STUDY OBJECTIVE: The aim was to study the effects of changes in ventilation variables on cardiac function during high frequency jet ventilation. DESIGN: Controlled changes in mean airway pressure (2-10 cm H2O), tidal volume (4 and 8 ml), and frequency (4-8 Hz) were used to assess the effects of ventilatory variables on cardiac output in cats with normal and reduced lung compliance during high frequency jet ventilation. Cardiac output was continuously measured with an electromagnetic flow probe placed around the aorta. Respiratory compliance was reduced by lung lavage. EXPERIMENTAL MATERIAL: Seven anaesthetised adults cats, weight 3.0(SEM 0.2) kg, were used in the study. MEASUREMENTS AND MAIN RESULTS: Cardiac output fell as mean airway pressure was raised from 2 to 10 cm H2O at all frequencies and tidal volumes. At identical levels of minute ventilation and mean airway pressure, cardiac output was improved with combinations of smaller tidal volumes and higher frequencies. Reducing respiratory compliance by lung lavage dampened the effect of mean airway pressure on cardiac output, but maintained the relationship between ventilatory variables observed before lavage. CONCLUSION: At identical settings of minute ventilation and mean airway pressure, cardiac output may be improved with smaller tidal volumes during high frequency jet ventilation.

Airway Resistance↗
PubMed1989

Cardiovascular effects of high-frequency oscillatory and jet ventilation.

To determine the effects of mean airway pressure on hemodynamics during high-frequency ventilation, we ventilated five cats (wt 2.8 +/- 0.6 kg) using both HFOV (frequencies 3 to 20 Hz) and HFJV (frequencies 4 to 8 Hz) at Paw values ranging from 2 to 12 cm H2O. Combinations of frequency and tidal volume that maintained normocapnia were employed in random order before and after reduction of static compliance of the respiratory system by lung lavage. Heart rate was comparable during both modes of high-frequency ventilation. During both HFOV and HFJV, the cardiac output decreased and PVR increased in normal and surfactant-deficient cats as Paw was elevated (all p less than 0.01, ANOVA). For both HFOV and HFJV linear regression of Paw and cardiac output yielded comparable slopes and y-intercepts. Lung lavage reduced the effect of Paw but did not eliminate it. Changes in ventilatory frequency did not affect cardiac output or PVR. We conclude that the interaction between high-frequency ventilation and cardiovascular function is largely determined by Paw and compliance and is independent of ventilator frequency and the type of ventilator used.

Animals↗
PubMed1988

Fetal and neonatal mortality of small-for-gestational age infants. A 15-year study of 381 cases.

Fetal and neonatal mortality of small-for-gestational age (SGA) infants in 1968-1982 were studied in the region of the University Central Hospital of Turku, Finland. During the study period, there were 254 fetal and 127 neonatal deaths in SGA infants. The fetal mortality rate of SGA infants declined from 49.9/1000 to 14.0/1000. The neonatal mortality rate of SGA infants declined from 23.8/1000 to 8.3/1000. The severely SGA infants with a birth weight below the 2.5th percentile had three times higher neonatal mortality rates than SGA infants with a birth weight between the 2.5th and the 10th percentiles. The main causes of fetal deaths were maternal diseases, placental and cord complications and fetal malnutrition, even though there was a decline in all these groups. Malformations remained the main cause of neonatal death during the study period, while there was a decline in deaths due to asphyxia and respiratory distress syndrome (RDS). The high mortality rates of SGA infants emphasize the need for early diagnosis and special attention during pregnancy, delivery and the neonatal period.

Birth Weight↗
PubMed1988

High Doppler-derived cardiac output in the cerebral arteriovenous fistula measured by pulsed Doppler ultrasound.

Cerebral arteriovenous fistula may cause a significant increase in cardiac output. So far, the right ventricular output measurement with conventional cardiac output methods has been difficult in newborn infants because of the shunts through the foramen ovale and patent ductus arteriosus. This difficulty can be avoided by measuring left ventricular output with the pulsed Doppler ultrasound method. In our case, the patient was a newborn infant with large patent ductus arteriosus and an arteriovenous malformation of the great cerebral vein of Galen. The malformation was found by noticing a loud murmur from the infant's head. The diagnosis was later confirmed by ultrasound scanning and a computer tomography. Left ventricular output was enormous with values from 740 to 830 ml/min/kg, when the normal value for the newborn infant at this age is 260 ml/min/kg. Because of constant cardiac failure, the malformation was operated on. The infant died of cardiac failure during this operation. An enormous left ventricle output in an infant with arteriovenous fistula and patent ductus arteriosus predisposes to cardiac failure. The Doppler ultrasound method in newborn infants seems to be a useful tool to determine cardiac function.

Blood Flow Velocity↗
PubMed1988

Developmental outcome of 519 small-for-gestational age children at the age of two years.

At the age of two years developmental outcome of 519 small-for-gestational age (SGA) children and 3375 control children was studied in southwestern Finland. A modification of the Denver Developmental Screening Test was used for follow-up. A significantly higher number of developmental abnormalities was found in SGA children than in the control children at the age of two years. Significant differences were found in walking, manual performance and comprehension between SGA and control children. Asphyxia was the only perinatal complication associated with later developmental abnormalities in SGA infants. Term SGA infants had a significantly higher frequency of developmental delays than term appropriate-for-gestational age (AGA) infants. In preterm infants no difference was found between SGA and AGA infants. Poor head growth during the first two years of life was an important risk factor for later developmental abnormality in SGA infants.

Child Development↗
PubMed1988

Impairment of hemodynamics with increasing mean airway pressure during high-frequency oscillatory ventilation.

We investigated the effects of changes in mean airway pressure (Paw), oscillatory frequency and lung compliance on cardiac output (CO) and pulmonary vascular resistance in seven adult cats (3.0 +/- 0.6 kg) during high-frequency oscillatory ventilation (HFOV). The cats were anesthetized with chloralose and urethane and ventilated with a high-frequency oscillator at Paw of 4, 8, 12, and 16 cm H2O and frequencies of 3, 6, 12, 16, and 20 Hz. Saline lavage was used to reduce lung compliance. CO was continuously recorded with an electromagnetic flow probe placed around the aorta and pulmonary vascular resistance was calculated from left atrial and pulmonary artery pressures. Lung lavage reduced static compliance of the respiratory system but did not change CO during pressure-limited ventilation. During HFOV, CO was higher in animals after lung lavage at each Paw. As Paw was raised from 4 to 16 cm H2O during HFOV, CO decreased from 133 +/- 36 to 87 +/- 31 ml/min kg in animals with normal lungs and decreased from 153 +/- 33 to 107 +/- 19 ml/min kg after lung lavage (both p less than 0.001). Increasing Paw was also associated with an increase in pulmonary vascular resistance both before and after lung lavage (both p less than 0.005). Changes in frequency did not significantly alter CO or pulmonary vascular resistance. We conclude that the interaction between the heart and lungs during HFOV is largely mediated by Paw and compliance of the respiratory system. Furthermore, regardless of the degree of lung compliance, cardiac function may be impaired during HFOV as Paw is elevated.

Animals↗
PubMed1987

Childhood bacterial meningitis: initial symptoms and signs related to age, and reasons for consulting a physician.

The relationship of symptoms and signs to age and the reasons for consulting a physician were analyzed in 110 cases of culture-proven childhood bacterial meningitis. H. influenzae caused 74, meningococci 28, pneumococci 6 and streptococci 2 of the cases. Apart from fever (present in 94%), the most common symptoms according to age were as follows: 1-5 months: irritability (85%), 6-11 months: impaired consciousness (79%), 12 months or more: vomiting (82%) and neck rigidity (78%). Absence of neck rigidity at diagnosis was associated with young age (less than 12 months, P less than 0.001) and, in older children, to a short duration of symptoms (P less than 0.01) but not to the degree of CSF pleocytosis. Symptoms of meningitis caused by H. influenzae differed from those of meningococcal meningitis. Meningitis should be suspected in irritable or lethargic febrile children despite absence of neck rigidity. Fever and vomiting were the most frequent reasons for consulting a physician (60% and 31%, respectively). Despite the frequency and alarming character of irritability, impaired consciousness and neck rigidity, their presence led infrequently to a consultation (6%, 22% and 3%, respectively). Parental ignorance of such symptoms or of their importance may cause treatment delay, despite readily available medical services.

Adolescent↗
PubMed1987

Carbon dioxide elimination during high-frequency jet ventilation.

The effects of frequency, tidal volume, and inadvertent positive end-expiratory pressure (PEEP) on CO2 elimination were studied in rabbits during high-frequency jet ventilation by measuring CO2 concentration of expired gas using a mass spectrometer. Increasing tidal volume augmented CO2 elimination (P less than 0.01 to 0.001) at each frequency, but when larger tidal volumes were associated with high inadvertent PEEP, CO2 elimination decreased despite the increase in minute ventilation. For constant minute ventilation, CO2 elimination decreased with increasing frequencies. Occurrence of inadvertent PEEP was related to increases in both frequency and tidal volume. If PEEP was controlled, no decrease in CO2 elimination was observed at the larger tidal volume. When PEEP was controlled, changes in tidal volume explained 67.1% to 95.4% of the variance in CO2 elimination not attributable to frequency. Frequency explained very little additional variance (0.1% to 13.8%). CO2 elimination comparable to estimated CO2 production occurred when tidal volumes equal to or smaller than the equipment dead space were used. We conclude that although tidal volume has a greater effect than frequency on CO2 elimination, mechanisms of gas exchange other than bulk gas transport occur during high-frequency jet ventilation.

Analysis of Variance↗
PubMed1987

Water, sodium and acid-base balance in premature infants: therapeutical aspects.

One of the main targets of fluid therapy in premature infants is to avoid variations in osmolality, which mainly means providing a stable sodium, glucose, and acid-base balance. Water, sodium, and acid-base balance were measured in 20 infants appropriate-for-gestational age with a gestational age less than or equal to 34 weeks. The infants were randomly assigned to one of two treatment groups. Fluid intake was restricted and air humidity in the incubator was high in order to minimize insensible water loss. Sodium intake in Group 1 was 2 mmol/kg/day and consisted of sodium chloride. Sodium intake in Group 2 was 4 mmol/kg/day and consisted of both sodium chloride and acetate. Weight loss was appropriate in both groups. In the high sodium intake group there was a tendency towards a more stable plasma sodium concentration than in the low sodium intake group. The use of sodium acetate was efficient and practical as normal acid-base balance was maintained. The protocol with restricted fluid intake (1st day 50 ml/kg, 2nd day 70 ml/kg, 3rd day 90 ml/kg, and 4th day 110 ml/kg), high air humidity, a sodium supply of 3 to 4 mmol/kg/day, and a slow correction of metabolic acidosis with sodium acetate, yields suitable guidelines in planning fluid and electrolyte therapy in premature infants less than or equal to 34 weeks' gestation.

Body Weight↗
PubMed1987

Growth of 519 small for gestational age infants during the first two years of life.

The physical growth of 519 small for gestational age infants (SGA), with a birth weight below the 10th percentile on our own growth curve, born in the region of University Central Hospital of Turku during the period June 1, 1981-May 31, 1982, was studied. The study population consists of 4,517 term, appropriate for gestational age (AGA) infants, 488 term SGA infants, 320 preterm AGA infants and 31 preterm SGA infants. The degree of intrauterine growth retardation (IUGR) seemed to have an effect on physical growth in term SGA infants. Those term SGA infants with a low Ponderal Index (PI) (type II) were taller and had a larger head circumference at the age of 24 months than term SGA infants with adequate PI (type I). Among the preterm SGA infants the degree of IUGR seemed to have no effect on later growth. Smoking is still one of the main risk factors associated with poor intrauterine growth. In this study we also found that smoking has an effect on later growth; the children of smoking mothers were smaller than those of non-smoking mothers in the AGA group. Among the SGA infants the infants of non-smoking mothers were bigger than those of smoking mothers. This difference could be explained by other factors associated with SGA. We found that in spite of the catch-up growth during the first months, 26% of the severely SGA infants (birth weight below the 2.5th percentile) still had a weight below the 2.5th percentile at the age of 24 months.

Birth Weight↗