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Biomedical subjects

G Rooth

Publications and source records attributed to G Rooth.

At least 19 recordsLinked to original sources
PubMed1994

Guidelines for blood sampling and measurement of pH and blood gas values in obstetrics. Based upon a workshop held in Zurich, Switzerland, March 19, 1993 by an Ad Hoc Committee.

Guidelines for the clinical indications for measuring pH and blood gas values in fetal blood, the procedures of blood sampling and measurement and some reference values for the evaluation of the data are given. They cover: prenatal sampling of blood from the umbilical vessels in conjunction with cordocentesis, intra partum sampling of fetal capillary blood by skin puncture of the presenting part, post partum sampling of blood from a clamped section of the umbilical cord and general analytical techniques.

Blood Gas Analysis↗
PubMed1992

The variability of cardiopulmonary adaptation to pregnancy at rest and during exercise.

OBJECTIVE: To examine the cardiopulmonary adaptation to normal pregnancy in sitting women during rest and bicycle exercise. DESIGN: A longitudinal study beginning early in pregnancy and ending 8-12 months after delivery. SETTING: University Hospital, Zurich, Switzerland. SUBJECTS: 20 women were monitored every second week during pregnancy from 8 to 14 weeks gestation, twice in the puerperium and twice 6-8 weeks and twice 8-12 months after delivery. All the women finished the study, but not all of them participated in every visit. MEASUREMENTS AND MAIN RESULTS: The results obtained 8-12 months after delivery are considered the non-pregnant data and are presented first so that any change in pregnancy will be more obvious. Values given below refer to the median except when stated otherwise. At rest: 1. Oxygen consumption increased significantly from a median of 182 ml/min in the non-pregnant state to 256 ml/min by 8-11 weeks gestation, and peaked at 300 ml/min at 32 weeks. At 6-8 weeks after delivery the value was 225 ml/min. 2. Oxygen consumption per kg increased significantly from 3.0 ml/min in the non-pregnant state to 4.3 ml/min by 8-11 weeks gestation and peaked at 5.0 ml/min soon after delivery. At 6-8 weeks after delivery the value was 3.4 ml/min. 3. Carbon dioxide production generally showed changes similar to those of oxygen consumption. 4. Respiratory quotient did not show any significant changes. 5. Ventilation increased from a median of 9.4 l/min in the non-pregnant state to 10.5 l/min by 8-11 weeks and then slowly increased to 12.6 l/min in late pregnancy. 6. Respiratory rate did not change significantly. 7. Tidal volume showed a median of 563 ml in the non-pregnant women and rose significantly to 632 ml in early pregnancy, peaking at 715 ml in late pregnancy. 8. Alveolar ventilation increased significantly from a non-pregnant value of 3.4 l/min to 6.2 l/min in early pregnancy, peaking at 6.7 l/min at term; 6-8 weeks after delivery the value was 4.5 l/min. 9. Ventilation equivalent for oxygen fell significantly from the median non-pregnant value of 52 to 42 in early pregnancy and remained at that level until 6-8 weeks after delivery when it was 44. 10. Ventilation equivalent for carbon dioxide showed similar changes to those for oxygen. 11. Alveolar carbon dioxide tension fell significantly from a median non-pregnant level of 4.6 kPa (34 mmHg) to 4.0 kPa (30 mmHg) in early pregnancy. It began to increase in the puerperium and was 4.3 kPa (33 mmHg) 6-8 weeks after delivery. 12. Mixed venous carbon dioxide tension fell significantly from a median of 5.9 kPa (44 mmHg) to 5.2 kPa (39 mmHg) during pregnancy. 13. Transcutaneous carbon dioxide tension decreased significantly in early pregnancy from 8.8 kPa (66 mmHg) in the non-pregnant women, and from 20 weeks gestation remained at 6.9 kPa (52 mmHg). 14. Transcutaneous oxygen tension showed a non-significant increase from 10.0 kPa (75 mmHg) in the non-pregnant women to 11.1 kPa (83 mmHg) during pregnancy. 15. Cardiac frequency increased gradually from a non-pregnant median of 80 b.p.m. to about 90 b.p.m. in the last 2 months of pregnancy. In the puerperium the median was 75 b.p.m. 16. Cardiac output increased significantly by almost 50% from the non-pregnancy level to that at 8-11 weeks gestation. 17. Cardiac output per kg also increased significantly by 50% from the non-pregnant level to that at 8-11 weeks gestation. From mid-pregnancy there was a gradual fall until delivery. 18. Stroke volume increased significantly from a median of 31 ml in the non-pregnant state to 51 ml in early pregnancy, and remained at this level until delivery. In the puerperium the stroke volume was 63 ml. 19. Oxygen pulse increased significantly from a median of 2.2 ml in the non-pregnant women to 3.1 ml in early pregnancy and remained at that level. 20. Individual curves.(ABSTRACT TRUNCATED AT 400 WORDS)

Adaptation, Physiological↗
PubMed1989

Peer review through perinatal statistics.

The purpose here is to demonstrate that perinatal statistics serve as a powerful tool for peer review, thereby improving the standard of maternity care. These data were used as an instrument for peer review, first by comparing perinatal mortality between one country and another. More detailed statistics, rapidly fed back to the delivery units, acted as a strong inducement to practitioners at all levels who wanted to do at least as well as their neighbors. Examples are given from Sweden, Scotland and Germany.

Female↗
PubMed1987

Skin reactive hyperemia recorded by a combined TcPO2 and laser Doppler sensor.

The tcPO2 electrode used at 37 degrees C monitors changes in cutaneous PO2 which at this temperature is mainly determined by the changes in blood flow. Laser Doppler velocimetry (LDV) measures the product of red cell number times their velocity. A comparison of these methods for the detection of skin reactive hyperemia has been made with a combined tcPO2 and laser Doppler sensor. The two parameters increased and decreased in parallel, the tcPO2 signal being delayed 10-20 s compared to the LDV signal. A significant correlation between the two signals was obtained (r = 0.73-0.93). In contrast, no significant correlation existed between the postocclusive peaks of the two signals recorded in 12 duplicate experiments. Comparing the peak amplitudes from the repeated recordings the tcPO2 signal showed a higher correlation coefficient (r = 0.91) and smaller intercept than the LDV signal (r = 0.74). Both methods can be used for non-invasive recordings of skin reactive hyperemia. The tcPO2 signal at 37 degrees C reflects changes in blood flow of the most superficial capillaries and reactive hyperemia can be monitored with high reproducibility. Only this signal can be used for calculation of skin blood flow. The LDV signal conveys information of blood flow changes mainly of deeper dermal vascular beds and reacts virtually instantaneously, but is less reproducible.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Combined electronic fetal heart rate and fetal movement monitor--a preliminary report.

We have tested a new Doppler ultrasound apparatus which registers both fetal movements and fetal heart rate with a single transducer. To evaluate the reliability of the recognition of movements we also observed them simultaneously by real time ultrasound. In 20 patients with normal pregnancies between the 30th and 42nd week of gestation, taking the real time ultrasound as reference the positive predictive value was 0.93 and the sensitivity 0.94. Maternal hiccups or coughing were recorded as fetal movements. Neither gestational age, the amount of amniotic fluid or the position of the placenta influenced the recognition of movement; nor did fetal breathing, maternal breathing, speaking or laughing.

Female↗
PubMed1987

Consequences of asphyxia in surfactant deficiency.

Consequences of asphyxia in babies with surfactant deficiency are discussed. Several important points concerning transition from intra- to extrauterine life are underlined. In asphyxia large amounts of hypoxanthine are formed and in the postasphyxic period when high concentrations of oxygen are given large amounts of oxygen radicals are produced. Experimentally we have shown that such radicals produce lung engorgement, hemorrhage and edema. Further they inactivate surfactant. Oxygen radicals also reduce the lung compliance dramatically in animal experiments. Saline alone given intratracheally to animals ventilated artificially will also reduce lung compliance. It is therefore not recommended to give saline intratracheally as a placebo in surfactant trials.

Adenine Nucleotides↗
PubMed1987

Transcutaneous oxygen monitors are reliable indicators of arterial oxygen tension (if used correctly).

The following recommendations should always be kept in mind: Each new transcutaneous equipment, or modification of equipment, must be adequately tested in vivo as well as in vitro. The users must have basic understanding of the principles and the major requirements for applying the tcPO2 technique. Calibration procedures must be carefully adhered to according to the manufacturer's instruction. The temperature of the electrode must be kept at 44 degrees C for premature infants and at 44 degrees or 45 degrees C for term infants if the clinical aim is to estimate arterial PO2 levels. Resetting of the electrode must then be done every two hours. For sick infants, this may be needed more frequently. Whenever there is cause to compare tcPO2 values with arterial ones, the latter must be obtained from an appropriate vessel. Great care must be taken when drawing and analyzing blood for PO2. The infant should not be crying. Significantly lower transcutaneous PO2 values than arterial PO2 values are due to either one or several of the errors indicated above or to an insufficient circulation under the electrode. In recent years, technical or clinical errors seem to have become more and more common. Thereby the technique has unjustly fallen into disrepute. Insufficient circulation under the electrode rarely occurs in the newborn infant and then only in those who are in overt shock.

Arteries↗
PubMed1985

Detection of exercise-induced lactic acidosis using transcutaneous carbon dioxide.

Transcutaneous PCO2 (PtcCO2) measurements were used to monitor changes in systemic lactate levels during exercise. PtcCO2 increased in all 17 male volunteers, and this increase was significantly correlated with increases in measured plasma lactate concentration. In six volunteers, the PtcCO2 increase was greatest during the last minutes of work, indicating rapid lactic acid elimination from the muscles. In these six subjects, the rate of this increase also correlated significantly with the lactate increase. This technique is potentially of interest for detecting fatigue in athletes and for monitoring lactoacidosis as an indicator of circulatory impairment in shock patients.

Acidosis↗
PubMed1985

Estimation of the "normal" growth of Swedish infants at term. Preliminary report.

Using the Swedish Medical Birth Registry for 1983 the birthweights were studied from the 38th to the 42nd week of gestation. Several criteria were used in order to retain a "normal" population of infants without signs of pathology. The mothers all negated smoking. Of about 93 000 livebirths roughly 10% fulfilled the criteria. Both in the infants who were the first-born child (n = 5.640) and in those who were the second-born child (n = 3.599) there was a successively higher mean birthweight for each completed week until 41 weeks. After that a graph connecting the mean values showed a significant flattening.

Birth Order↗
PubMed1985

Anaerobic skin metabolism in healthy men estimated with transcutaneous PCO2 electrode.

It is shown how the anaerobic energy production of the skin may be calculated from a transcutaneous PCO2 curve obtained at 37 degrees C during arterial occlusion. Thirty healthy volunteers were studied three times. The inter-individual differences in estimated ATP production were highly significant, but the intra-individual ones were not. The grand mean of the triplicate experiments of all the 30 subjects was an ATP production rate of 0.33 mmol X l-1 X min-1. Assuming no initial metabolic acidosis or alkalosis, the estimated mean extracellular fluid pH was 7.33 before and 7.26 after 4 min of stasis.

Adenosine Triphosphate↗
PubMed1985

Neonatal oxygen-cardiorespirograms.

To those used to intermittent blood sampling, intermittent viewing of ECG, or intermittent counting of heart and respiratory rates, the rapid changes in these variables, as revealed when monitored continuously, must come as a surprise. These rapid changes are found even in quiet, healthy infants. Because of this variability and the diagnostic significance of each single variable, the potential of these variables can be utilized only if they are continuously recorded. It is like studying movement from a videorecording instead of from a couple of photographs taken at different intervals. Knowing normal levels and the trend of changes in all the variables, it becomes easier and more accurate to predict significant clinical changes than before. Or, in M. E. Avery's words, "Those of us who have used continuous monitors would not like to return to the era of sporadic sampling of information."

Electrocardiography↗
PubMed1983

Some effects of maternal pethidine administration on the newborn.

The effects of maternal pethidine administration (100 mg intramuscularly) were investigated in 150 infants at 1-2 h after birth, 95 infants whose mothers had not received pethidine served as a control group. Pethidine administration showed no effect on pH or PCO2 of cord blood and neonatal arterial blood at 1-2 h after birth if the time interval between pethidine administration and delivery was less than or equal to 1 h. However, when the interval was greater than 1 h: umbilical vein blood PCO2 was higher; neonatal arterial blood PCO2 was higher; neonatal baseline heart rate was higher, although long-term variability was similar; the percentage time spent crying was considerably reduced compared with the corresponding values in the control group. The long-term effects of pethidine are unknown but the adverse neonatal factors particularly if the time interval between administration of the drug and delivery is greater than 1 h should be kept in mind.

Carbon Dioxide↗
PubMed1982

Maternal hypoxaemia during labor.

A review is given covering four different series of studies revealing maternal hypoxaemia during labour, in spite of normal maternal heart and lung function. The previous Swedish use of 100% nitrous oxide inhalation during contractions lead to serious maternal hypoxaemia. The use of pethidine in combination with hyperventilation during the contractions leads to long respiratory pauses and maternal hypoxaemia in between the contractions. Excessive hyperventilation during the contractions may in itself lead to a so called hyperventilation-hypoventilation syndrome with maternal hypoxaemia. Finally excessive sustained pushing with maximal effort and no ventilation also leads to maternal hypoxaemia. Thus maternal hypoxaemia, although largely unknown is not too infrequent and is mainly of iatrogenic origin. Proper knowledge should suffice for prevention.

Carbon Dioxide↗
PubMed1981

Distribution of observed patterns in fetal transcutaneous oxygen tension.

The interaction between intrauterine pressure, fetal heart rate, and fetal transcutaneous oxygen tension (tcPO2) may be classified into 10 pattern types. Eight of them indicate the reduction in fetal tcPO2 caused by uterine contractions and by fetal heart rate decelerations. Two pattern types show the effect of stasis and of pressure resulting in decreased fetal tcPO2. In 32 recordings from Uppsala, Sweden, and 11 from Zurich, Switzerland, 1,161 contractions were analyzed. A similar distribution of the patterns was found in the two hospitals in uncomplicated deliveries in the first stage of labor. In 15% of the contractions in the first stage of labor, fetal tcPO2 was affected by stasis or pressure, whereas this occurred in 48% of the 265 contractions in the second stage of labor. Thus, in most instances, fetal tcPO2 should be expected to give reliable information in the first stage, whereas the stasis and the pressure pattern must be recognized for the evaluation of fetal tcPO2 in the second stage of labor.

Female↗
PubMed1981

Early reduction of vascular reactivity in diabetic children detected by transcutaneous oxygen electrode.

Reactive hyperaemia in the skin was monitored by transcutaneous measurement of PO2 (tcPO2) (using electrode temperatures of 35 and 37 degrees C) in 13 well controlled diabetic children without clinical signs of vascular disease, and in healthy peers matched for age and sex. The tcPO2 increase was smaller in 12 of the 13 diabetic children than in individual controls. Taking the lower limit of the 95% confidence interval of the increases for the healthy children as a cut-off point, only 4 of the 13 diabetic children had values overlapping into the range of non-diabetics at 37 degrees C. This non-invasive technique, demonstrating a reduced postischaemic response in a group of well controlled diabetic children, may become a useful method for the early detection of diabetic microvascular disorders.

Adolescent↗