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G Simbruner

Publications and source records attributed to G Simbruner.

At least 37 records · Page 2Linked to original sources
PubMed1989

Comparison of two airway occlusion methods for determining the compliance of the respiratory system (Crs) in newborn infants.

We investigated 11 spontaneously newborn infants (birth weight 1400 to 3120 g) on their first day of life. Measuring inspired gas volume (VI) and the mouth pressure obtained at inspiratory airway occlusion (Pocc) we calculated the compliance of the respiratory system (Crs): a) by linear regression analysis of the VI/Pocc measurements obtained at various VI (Olinsky, et al., 1976) and b) as the mean of 3 endinspiratory VI/Pocc measurements (modified airway occlusion method (Simbruner et al., 1982). There was a close linear correlation between the Crs values obtained by both methods (r = 0.98, p less than 0.001; Crs(a) = 0.669 x Crs(b) + 0.428), indicating that the simpler modified airway occlusion method (b) may be used instead of the original method (a) for determining Crs on the first day of life in spontaneously breathing newborn infants.

Airway Resistance↗
PubMed1989

Heat flux from the head surface in healthy newborns and in newborns with cerebral pathology.

Scalp heat flux of fetuses during labor was shown to be related to metabolic and circulatory factors. We therefore investigated whether heat flux from the head of newborns was also related to cerebral pathology. Heat flux from the head was measured in three groups: Group A consisted of 7 newborn infants with micro- and/or hydrocephalus and with cerebral asphyxia, who were considered to have decreased heat flux from the head due to decreased heat production. Group B consisted of 3 newborn infants with hypoplastic left heart syndrome, who were considered to have increased heat flux from the head due to low cerebral blood flow and, thus, decreased heat convection from the brain. Group C consisted of 17 randomly selected healthy neonates, who served as controls. Heat flux from the head was measured by heat flux transducers attached to the skin of the forehead. The effective operative temperature in the incubator was measured with thermistors. The heat flux from the head of neonates with micro-and/or hydrocephalus and of neonates with cerebral asphyxia was distinctly below, the heat flux from the head of the neonates with hypoplastic left heart syndrome were above two standard deviations of the mean of the heat flux of healthy neonates. The results suggest that heat flux from the head is related to the metabolic or circulatory condition of the underlying brain.

Asphyxia Neonatorum↗
PubMed1989

Influence of tidal volume on the compliance of the respiratory system in mechanically ventilated newborn infants.

We measured the compliance of the respiratory system (Crs) at 4 different tidal volumes (VT = 2.5, 5.0, 7.5, 10.0 ml/kg) in 29 mechanically ventilated newborn infants and determined the VT associated with the highest Crs ("optimal" VT) and with the lowest Crs ("worst" VT). Crs depended on the VT in all newborn infants investigated. The "optimal" VT most frequently observed was 2.5 and 5.0 ml/kg and the "worst" VT most frequently observed was 2.5 and 10.0 ml/kg. Mean Crs at the "optimal" VT was 62.3% higher than at the "worst" VT. The "optimal" VT was lower (2.5 ml/kg) in newborn infants with controlled ventilation than in newborn infants with intermittent mandatory ventilation (5.0 ml/kg). We conclude that it may be useful to determine the VT associated with the highest Crs in order to avoid unnecessarily high inflation pressures for the mechanical ventilation of newborn infants. Further studies are needed to assess long-term effects of such a Crs guided respirator therapy.

Humans↗
PubMed1989

Cerebral blood flow in newborn infants with and without mechanical ventilation.

The influence of mechanical ventilation with low mean airway pressure (MAP) on cerebral blood flow (CBF) veolocity in newborn infants was assessed in fifteen ventilated infants by Duplex Doppler Sonography (Duplex DS). As a control, CBF velocities were examined in 15 age and weight matched non-ventilated infants. For quantitation, maximal systolic velocity, enddiastolic velocity and the semiquantitative Pourcelot index were determined as representative flow variables. There was no significant difference of these flow variables between ventilated and non-ventilated infants. The pH, pO2 and pCO2 did not differ significantly between the two groups and there was no correlation between the flow variables, pH, pO2, pCO2 or MAP. Mechanical ventilation with low MAP is not associated with adverse effects on cerebral hemodynamics in newborn infants when significant alterations of the blood gases are avoided.

Cerebral Arteries↗
PubMed1988

[External ventricle drainage in newborn infants with rapidly growing posthemorrhagic hydrocephalus].

14 newborn infants (birth weight: 1830 +/- 930 gms, gestational age 33 +/- 4 wks) (mean +/- SD) with rapidly progressive posthaemorrhagic hydrocephalus and increased intracranial pressure were treated by means of external ventricular drainage. Progression of hydrocephalus was arrested during the drainage period in each patient. The drainage was kept in place for 20 +/- 12 days, the longest drainage period being 48 days. 8 of 10 surviving patients showed recurrence of progressive ventricular dilatation, 5 required a ventriculoatrial and 3 a ventriculoperitoneal shunt. The other 2 infants required no further therapy. Implantation of a permanent shunt was performed at day 28 to 88 after delivery, at the time of implantation the weight of the infants was 2400 +/- 950 gms (lowest weight 1650 gms). Bacterial cultures of ventricular liquor were negative in 66 and positive in 7 instances. Clinical and biochemical evidence of ventriculitis was absent in all patients. 4 of the 14 patients died of causes unrelated to external ventricular drainage. 10 infants survived. 7 out of 10 survivors suffered from IVH 3; 6 subsequently showed normal neurological development and one was retarded. 3 patients with parenchymal lesions (2 patients: IVH 4, 1 patient: primarily intraparenchymal haemorrhage) had neurological handicaps. We consider external ventricular drainage to be an effective form of therapy in newborn infants with rapidly progressive posthaemorrhagic hydrocephalus and increased intracranial pressure because this treatment achieves prompt and sustained decrease in intraventricular pressure without complications.

Cerebral Hemorrhage↗
PubMed1988

Comparison between dynamic lung compliance and static compliance of the respiratory system in sick newborn infants.

We compared dynamic lung compliance (Cldyn) determined by the oesophageal balloon technique with static compliance of the respiratory system (Crs) determined by an airway occlusion technique in 10 newborn infants with various cardio-respiratory diseases. The correlation between the two variables was linear and statistically significant (r = 0.911, p less than 0.0003; Cldyn = 1.51.Crs-0.48). Crs varied significantly less than Cldyn (mean coefficient of variation 3.9 for Crs vs. 9.3 for Cldyn; t = 6.06, p less than 0.0002). Since Crs is closely related to lung compliance but a more reliable parameter and technically easier to assess, we recommend the assessment of Crs instead of Cldyn in clinical practice.

Female↗
PubMed1988

Respiratory compliance of healthy newborn infants measured by endinspiratory airway occlusion technique in the first hours of life.

The compliance of the respiratory system (Crs) has been measured by an airway occlusion technique in 78 healthy newborn infants [gestational age (GA) 36.2 +/- 2.9 weeks, range 28-41 weeks; birth weight (BW) 2.418 +/- 0.879 kg, range 0.830-4.350 kg; body height (BH) 45.2 +/- 4.4 cm, range 33-52 cm in the first 8 h after birth (206.2 +/- 100.8 min, range 45-480 min). The prediction equations were (Crs, ml/cm H2O): Crs = 0.087.GA -1.173 (r = 0.49, p less than 0.0001), Crs = 0.372.BW +1.067 (r = 0.62, p less than 0.0001), Crs = 0.076.BH -1.493 (r = 0.61, p less than 0.0001). The Crs values were very similar to the values measured in curarized newborn infants and quoted in the literature. There was only one newborn infant with a Crs of less than 1 ml/cm H2O (GA = 34 weeks, BW = 0.830 kg, BH = 33 cm, Crs = 0.909 ml/cm H2O).

Birth Weight↗
PubMed1987

[Can muscle relaxation prevent the development of pneumothorax in artificially ventilated newborn infants?].

A retrospective study was conducted on 37 ventilated newborn infants to find out whether muscle paralysis by pancuronium had prevented pneumothorax (pt) in those severely ill newborn infants. In the group of 21 newborns who developed pt, 17 (81%) had been paralyzed with pancuronium. In the group of 16 newborns without pt, 10 (61%) had received pancuronium (chi 2 = 1,568, ns). Thus, muscular paralysis had not prevented pt. Since the newborns in both groups were equally severely ill (mean compliance of the respiratory system 0.48 +/- 0.17 ml/cm H20 in the group with pt, 0.38 +/- 0.12 in the group without pt), we assume that pancuronium was unable to prevent pt in ventilated premature and full-term newborn infants. We therefore caution against the use of pancuronium as a paralytic drug known to have deleterious side effects.

Humans↗
PubMed1987

Scalp heat flux and its relationship to scalp blood pH of the fetus.

A method for directly assessing the metabolic rate of the fetus for optimal management of labor and delivery is still being studied. Since heat, an end product of metabolism, is dissipated from the fetal surface, we measured the heat flux from the fetal scalp and related it to the pH of fetal scalp blood, a measure of metabolism. In 25 human fetuses at risk of intrapartum hypoxia, after the membranes had ruptured and the cervix dilated to greater than 3 cm, we attached a heat flux transducer, a platelet of 2.5 cm diameter and 1 mm thickness, to the fetal scalp and recorded continuously the heat flux from then until delivery. We also obtained one sample of fetal scalp blood in all patients and two such samples in 13 patients for the analysis of pH. We found a significant correlation between heat flux measured immediately before the scalp blood sampling (presampling values) and the pH of fetal scalp blood (r = 0.736; n = 18 presampling values; p less than 0.001). Out of 13 fetuses with two scalp blood samples, the changes in the scalp heat flux paralleled changes in scalp blood pH in 11. We conclude that fetal scalp heat flux is related to the metabolic condition of the fetus. Measuring scalp heat flux during labor could be developed into a noninvasive method for a continuous and more direct assessment of the fetal metabolic rate.

Adult↗
PubMed1987

[Relation between pulsed and continuous Doppler velocimetry of the anterior cerebral artery in newborn infants].

Continuous wave (cw) and pulsed wave (pw) Doppler velocimetry are both used to measure blood flow velocity in cerebral arteries. We examined whether data obtained with the two methods are interchangeable and equally useful for clinical application. We studied 20 infants at an age between 1 day and 2 1/2 months and a body weight between 1.2 and 3.4 kg. Cw Doppler measurements were performed using an Angiomatic (Medimatic) and pw measurements using a Mark 600 Duplex Scanner (ATL). We applied both methods within an interval as short as possible. For the data analysis the pulsatility index (PI) was used, a parameter fairly independent of the emission angle. PI was 0.66 +/- 0.06 (mean +/- SD) using the cw and 0.8 +/- 0.08 using the pw method. The linear correlation between the pulsatility indices obtained with the cw and the pw method respectively was statistically significant (r = 0.53, n = 20, p less than 0.0025), the variation around the regression line rather large. The slope of the regression line differed significantly from that of the identity line (y = 0.391x + 0.54). Therefore the PI values obtained with the two methods are not interchangable and require to be judged according to normal values. Both methods, however, yield PI values which correlate and can thus be equally used. The choice of the method rather depends on the goal to be achieved. The pw method seems to be more suitable for precise momentaneous descriptions and the cw method for continuous monitoring of cerebral blood flow.

Blood Flow Velocity↗
PubMed1986

Digoxin levels in the serum of healthy neonates.

The possible existence of a chemical substance with cross-reactivity to digoxin antibodies in the neonatal serum or plasma was investigated in this study. Our data show that in contrast to previous reports, the levels of a "digoxin-like substance" in the serum or plasma of healthy newborns are negligible and probably would not affect the reliability of digoxin radioimmunoassay tests.

Cross Reactions↗
PubMed1986

Inadvertent positive end-expiratory pressure in mechanically ventilated newborn infants: detection and effect on lung mechanics and gas exchange.

During mechanical ventilation, inadvertent positive end-expiratory pressure (PEEP) can have deleterious effects, including decreasing lung compliance and alveolar ventilation. To detect and quantitate inadvertent PEEP in 10 preterm neonates receiving mechanical ventilation, we clamped the connection between the endotracheal tube and the respirator at end-expiration and, after about 5 seconds, measured the airway pressure resulting from the trapped gas that emptied into the airways and the measuring system. To study the effect of decreasing inadvertent PEEP on lung mechanics and gas exchange, we measured the compliance of the respiratory system and blood gases. Inadvertent PEEP greater than 1 cm H2O was detected in 19 of 29 measurements. Decreasing inadvertent PEEP by lengthening the expiratory time increased the compliance of the respiratory system (r = -0.74, n = 10, P less than 0.02). Decreasing inadvertent PEEP by greater than 1 cm H2O (mean 2.1 +/- 0.8 cm H2O) in six newborn infants increased respiratory compliance from 0.57 +/- 0.09 to 0.73 +/- 0.13 ml/cm H2O, or approximately 30%, and lowered Pco2 from 40.6 +/- 14.4 to 38.2 +/- 14.1 mm Hg despite a reduction in the level of ventilation set on the respirator. Knowing the amount of inadvertent PEEP and its effects can help improve mechanical ventilation in newborn infants.

Carbon Dioxide↗
PubMed1986

[Ambroxol in comparison with betamethasone for the stimulation of antepartal lung maturity. A clinical double-blind study].

Stimulation of the surfactant production in fetal cells by ambroxol (metabolite VIII of bromhexine) has been investigated in human and animal experiments. There are no contraindications for the prenatal use of ambroxol, which is also well tolerated in high dose. Therefore the 1st Department of Obstetrics and Gynecology in Vienna took part in a multicentric clinical trial, where the allocation between cortisone and ambroxol was randomised in a double blind fashion. The 1st Department included 34 women between 30 and 36 weeks of pregnancy with premature labour or indicated premature induction. Amniotic fluid samples were taken by amniocentesis before therapy to prove lung immaturity by measurement of the L/S ratio and the dynamic surface tension. Following doses were used for this clinical trial group A: 1,000 mg ambroxol in 500 ml 5% glucose infusion i.v. daily from day 1 to day 5 and 2 ml placebo-injection i.m. on day 1 and day 2, group B: 8 mg Betamethasone i.m. on day 1 and day 2 and 500 ml 5% glucose infusion with a placebo daily from day 1 to day 5. The patients were treated at least 3 days; in all cases amniotic fluid samples were taken after therapy, to examine the L/S ratio and the dynamic surface tension. 29 women of the 34 fulfilled the above criteria, 15 in group A and 14 in group B (1 twin pregnancy). With the pretreatment parameters of lung maturity being similar in both groups ambroxol was found to lead to a marked but not significant improvement of the L/S ratio and the surface tension.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambroxol↗