PubMed Health⌕ Search

Biomedical subjects

G Simbruner

Publications and source records attributed to G Simbruner.

At least 19 recordsLinked to original sources
PubMed2001

Methodological investigation of measuring nasopharyngeal temperature as noninvasive brain temperature analogue in the neonate.

OBJECTIVES: (a) To investigate in a newborn animal model whether nasopharyngeal temperature is more closely related to epidural brain temperature than rectal temperature and (b) to investigate in human neonates whether measurement of nasopharyngeal temperature is dependent on the measurement site and other conditions. DESIGN AND SETTING: (a) Animal experiment in newborn piglets, at an institute for surgical research. (b) Prospective study in human neonates, at a neonatal intensive care unit of a tertiary care university hospital. ANIMALS AND PATIENTS: (a) Nineteen tracheostomized ventilated newborn piglets. (b) Twenty-two spontaneously breathing human newborns nursed either in an incubator or a cot. MEASUREMENTS AND RESULTS: (a) In the piglets nasopharyngeal temperature (Tnasoph) measured at the nose-ear distance, defined as distance from the inner brim of the nostril to the tragus and inner rim of the meatus accusticus, most closely reflected epidural temperature (Tepidur) at the epidural surface (r2 = 0.89), followed by skin temperature at the temple, rectal temperature (Trectum) at 2 cm depth, and esophageal temperature (Tesoph) in the middle esophagus. Tnasoph did not significantly differ before and after tracheostomy. (b) In the newborns Tnasoph was significantly lower than Trectum. Measurements of Tnasoph at nose-ear distance within a feeding tube had a high precision and were unaffected by breathing or head turning. A nasopharyngeal probe was imaged by magnetic resonance imaging in four newborns of various body weight; its tip when inserted to a depth equal to nose-ear distance was anatomically closest to the brain base but separated from it by tissue layer 2.2 cm thick. CONCLUSIONS: Tnasoph measured at a position anatomically closest to the brain reflects epidural brain temperature more closely than Trectum. When measured at nose-ear distance it is unaffected by breathing or head turning. Measuring Tnasoph within a feeding tube and standardizing the measuring position is crucial for its use as brain temperature analogue.

Animals↗
PubMed2000

Effect of lung water content, manipulated by intratracheal furosemide, surfactant, or a mixture of both, on compliance and viscoelastic tissue forces in lung-lavaged newborn piglets.

OBJECTIVE: To study the impact of lung water content and its reduction by a topically applied diuretic on respiratory and lung tissue mechanics in comparison with surfactant administration in surfactant-deficient newborn piglets with lavage-induced lung injury. DESIGN: Controlled, randomized study. SETTING: Animal research facility. SUBJECTS: Newborn piglets. TREATMENT Piglets were surfactant depleted by lung lavage and, after a pretreatment period, randomly treated with intratracheal furosemide, furosemide and surfactant, or with surfactant alone. MEASUREMENTS AND MAIN RESULTS: Dynamic compliance (C(DYN)), static compliance (C(ST)), stress-adaptation pressures (P(DIFF)) and post mortem lung water content were determined. Static compliance in the furosemide-surfactant group was not significantly higher than in the surfactant group. At the end of the study, C(ST) did not differ between the three groups because C(ST) in the furosemide group had increased to values similar to those of the surfactant-containing treatment groups: C(ST) F+S: 0.73 +/- 0.2 mL/cm H2O/kg body weight (BW); C(ST) S: 0.61 +/- 0.11 mL/cm H2O/kg BW; and C(ST) F: 0.60 +/- 0.19 mL/cm H2O/kg BW). Compliance was inversely and P(DIFF) was directly correlated to lung water (LW) content (C(ST) vs. LW: r2 = .59, p = .001; C(DYN) vs. LW: r2 = .49, p = .006; P(DIFF) vs. LW: r2 = .37, p = .059), independent of the type of treatment. Changes in C(ST) and C(DYN) were inversely related to changes in P(DIFF). Intrapulmonary furosemide was more rapidly absorbed when administered to the surfactant-depleted lung alone compared with the mixture with surfactant, and intrapulmonary furosemide had a rapid systemic effect. CONCLUSION: Although the combination of surfactant with a diuretic failed to increase respiratory compliance to a significantly larger extent than surfactant alone, furosemide at the end of the study increased respiratory compliance to a level similar to surfactant-containing treatments. Lung water content and, to a lesser extent, the absence or presence of surfactant appeared to determine lung mechanics, and its impact on lung mechanics was similar to surfactant administration.

Animals↗
PubMed1999

Induced brain hypothermia in asphyxiated human newborn infants: a retrospective chart analysis of physiological and adverse effects.

OBJECTIVE: To assess the physiological effects and adverse side-effects of induced hypothermia in asphyxiated newborn infants as a base for future controlled, randomized trials. DESIGN: Retrospective chart analysis with historical controls. SETTING: Tertiary neonatal intensive care unit of the University of Cape Town, South Africa. PATIENTS: Twenty-one asphyxiated newborns treated with induced hypothermia between September 1997 and February 1998 were compared to 15 asphyxiated newborn infants admitted during March to August 1997. The two groups of infants did not differ in patient characteristics or severity of asphyxia (comparison group vs hypothermia group: Apgar at 5 min 5.3 +/- 3.1 vs 5.2 +/- 2.3; base deficit 15.6 +/- 6.3 vs 11.5 +/- 7.2 and Thompson neurological score 10.1 +/- 4.0 vs 9.1 +/- 3.6). INTERVENTIONS: Hypothermia was induced by placing a cap formed from coolpacks, at a temperature of about 10 degrees C, around the head of asphyxiated newborn infants to maintain the nasopharyngeal temperature between 34 and 35 degrees C. Hypothermia was maintained for 3 days. MEASUREMENTS AND RESULTS: In the comparison group 4/15 infants died and in the hypothermia group 4/21 died. Hypothermia was induced at a median of 6.0 h (range 45 min to 53 h) post-partum, maintained for an average of 80 h (median 77.5 h, range 22 to 185 h) and resulted in an average nasopharyngeal temperature of 34.6 +/- 0.5 degrees C. Hypothermia reduced abdominal skin temperature from 36.3 +/- 0.5 degrees C to 35.1 +/- 0.35 degrees C (p = 0.0001), heart rate from 139 +/- 21 to 121 +/- 13 beats/min (p < 0.0001) and respiratory rate from 67 +/- 11 to 56 +/- 9 breaths/min (p = 0.005). Neither episodes of bradycardia nor dysrhythmias, apnea, clinical signs of bleeding diathesis in the hypothermia group nor differences in the frequency of hypoglycaemia and urinary output, blood in urine or tracheal secretion between the two groups were observed. In the survivors the neurological score, assessed at day 2 and day 5, fell from 10.9 +/- 3.5 to 8.1 +/- 4.5 in the hypothermia group and rose from 8.1 +/- 2. 5 to 9.0 +/- 3.1 in the comparison group (p = 0.003). CONCLUSIONS: Adverse effects of mild hypothermia induced for 3 days in asphyxiated newborns were significantly less than expected from previous reports on neonates with accidental hypothermia.

Apgar Score↗
PubMed1998

Interleukin-1 receptor antagonist and interleukin-6 for early diagnosis of neonatal sepsis 2 days before clinical manifestation.

BACKGROUND: Neonatal sepsis is a common and life-threatening disorder, particularly among preterm infants. Early initiation of antibiotic therapy is frequently delayed because the first clinical signs of sepsis are non-specific and there are no reliable early laboratory indicators. We investigated the time course of expression and the prognostic power of the early inflammatory mediators interleukin-1 receptor antagonist (IL-1ra), interleukin-6 (IL-6), and circulating intercellular adhesion molecule-1 (cICAM-1) before clinical diagnosis of sepsis. METHODS: In a prospective multicentre study, we monitored 182 very-low-birthweight infants in six intensive-care units for occurrence of sepsis. During routine or clinically indicated blood sampling, an additional sample was collected for measurement of IL-1ra, IL-6, cICAM-1, and C-reactive protein (CRP). Infants were grouped into those with proven sepsis, no infection, or unclassified. The mean study duration was 34 days. Whenever sepsis occurred, a study period of 10 days was defined: day 0 was the day of clinical diagnosis of sepsis; days -4 to -1 were the 4 days before diagnosis; days +1 to +5 were the 5 days after. We compared the concentrations of the immune mediators during the 10-day study period with group-specific baseline values from before day -4. FINDINGS: 101 infants were included in the analysis: 21 with proven sepsis, 20 with no infection, and 60 unclassified. We excluded 57 because of incomplete datasets and 24 who had early-onset sepsis. IL-1ra and IL-6 increased significantly 2 days before diagnosis of sepsis; maximum median increases within the study period were 15-fold for IL-1ra and 12-fold for IL-6. The diagnostic sensitivities of IL-1ra, IL-6, and CRP concentrations on day 0 of diagnosis were 93%, 86%, and 43%, respectively; corresponding values on day -1 were 64%, 57%, and 18%. The specificities of IL-1ra, IL-6, and CRP concentrations were 92%, 83%, and 93%. cICAM-1 had a specificity of only 64%. INTERPRETATION: IL-1ra and IL-6 are superior to cICAM-1 and CRP as predictors of sepsis 1 or more days before clinical diagnosis. Ad-hoc measurement of these cytokines could allow earlier initiation of antibiotic therapy with corresponding improvement in outcome in very-low-birthweight infants with sepsis.

Austria↗
PubMed1997

Intratracheal furosemide in infants after cardiac surgery: its effects on lung mechanics and urinary output, and its levels in plasma and tracheal aspirate.

OBJECTIVE: Recent studies have suggested direct pulmonary effects of furosemide in asthmatics and infants with bronchopulmonary dysplasia. We tested the hypothesis that intratracheally administered furosemide also increases respiratory compliance in children after cardiac surgery, and investigated whether furosemide has a topical and/or systemic action. STUDY DESIGN: Prospective study with intra-individual control. In twelve infants and toddlers (age: 10 +/- 8 months, weight: 6.9 +/- 3 kg) mechanically ventilated for compromised lung mechanics after cardiac surgery, 0.5 mg/kg furosemide was intratracheally administered to the lungs. Lung mechanics were serially assessed using a computerised system (Sensormedics 2600) during a 2 h control and 2 h intervention period. Urine output was measured by an indwelling bladder catheter and levels of furosemide were determined in blood and tracheal aspirates. RESULTS: Static compliance improved within 30 min in all patients, reached a maximum of 44 (20-85)% above baseline and remained improved throughout the study (p < 0.05). An immediate, short and significant diuretic effect of intratracheally applied furosemide was observed. Furosemide levels 1 h after intervention were 795 ng/ml in the blood and 431 micrograms/ml (i.e. 1000-fold higher) in the tracheal aspirate. Changes in compliance were correlated only to urine output values over the 2 h (r = 0.82, p = 0.044, n = 9) after furosemide administration. CONCLUSION: We conclude that intratracheally applied furosemide improves static compliance in infants and toddlers with compromised lung mechanics after cardiac surgery. We demonstrated that furosemide is absorbed from the lung and has a systemic effect within 15 min after its intratracheal instillation.

Administration, Topical↗
PubMed1995

Quasistatic volume-pressure curve to predict the effects of positive end-expiratory pressure on lung mechanics and gas exchange in neonates ventilated for respiratory distress syndrome.

The shape of the volume-pressure (V/P) curve indicates alveolar collapse if it is convex to the pressure axis and indicates overdistension if it is concave. Positive end-expiratory pressure (PEEP) should either improve or decrease compliance and oxygenation in neonates ventilated for respiratory distress syndrome (RDS), depending on predominance of either alveolar collapse or overdistension. To test this hypothesis, we determined quasistatic V/P curves in 13 preterm neonates and characterized their shape by an alveolar distension index (ADI) at PEEP levels of 2, 4, and 6 cm H2O. We calculated the ADI dividing the V/P ratio at a low tidal volume by the V/P ratio at a high tidal volume. This ADI was then related to the effect of PEEP changes on respiratory compliance and alveolar to arterial oxygen tension difference (AaDO2). ADI was assumed to indicate alveolar collapse if less than 1 and overdistension if more than 1. An increased PEEP in neonates with alveolar collapse (ADI less than 1) decreased AaDO2 more (12 vs 10 mm Hg/cm PEEP, not significant) and decreased compliance less (3 vs 17%/cm PEEP; P < 0.05) than in those neonates with alveolar overdistension (ADI more than 1). Conversely, a decreased PEEP in neonates with alveolar overdistension increased compliance more (19 vs 5%; not significant) and increased AaDO2 less (7 vs 26 mm Hg; P < .01) than in those with alveolar collapse. AaDO2 and compliance changes after PEEP alterations were significantly correlated to the ADI before PEEP alterations (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1994

Brain temperature discriminates between neonates with damaged, hypoperfused, and normal brains.

Brain temperature depends on the balance of cerebral heat production and heat loss via cerebral circulation and head surface. We investigated whether brain temperature and heat loss via the head surface differed in neonates with abnormal cerebral metabolism or circulation. We measured the core temperature of the head noninvasively by the zero-gradient method, skin temperature of the head, the heat flux from the head, and esophageal and operative environmental temperature in seven healthy neonates, seven neonates with cerebral damage, and two neonates with cerebral hypoperfusion caused by an incurable congenital heart disease. Cerebral blood flow velocity in the anterior cerebral artery and systemic blood pressure were also measured. Brain temperature profile was measured in two premature infants with external ventricular drainage. Core temperature of the head, considered to represent brain temperature, was up to 1.5 degree C higher in infants with cerebral hypoperfusion than in normal neonates. The core temperature of the head was higher than the esophageal temperature in all except two infants with the most severe cerebral damage. The difference between core temperature of the head and esophageal temperature was 0.72 +/- 0.12 degree C in normal neonates, 0.16 +/- 0.4 degree C in infants with cerebral damage, and ranged from 0.9 to 1.2 degree C in infants with cerebral hypoperfusion. The relationship of core of the head to esophageal temperature discriminated between all 16 newborn infants according to their brain pathologic condition, except one infant with a mild ischemic-hypoxic encephalopathy. In conclusion, brain temperature depends on cerebral perfusion and level of brain injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1993

Respiratory compliance assessed from chest expansion and inflation pressure in ventilated neonates.

We evaluated a bedside method of assessing respiratory compliance from chest expansion, which is judged by eye and classified into three tidal volume categories, and from the inflation pressure read on the respirator's manometer. Compliance assessed by this method was compared with the compliance measured by the injection technique in 45 randomly chosen newborns ventilated for various diseases. The compliance assessed from chest expansion and inflation pressure correlated significantly with the measured compliance (r = 0.86, p < 0.001). Interobserver reliability was acceptable for clinical practice and improved within 6 months of training (weighted kappa = 0.67 versus 0.86). Within ten individuals, changes of compliance assessed by this method were also significantly correlated with those of measured compliance (r = 0.85, p < 0.01). This method, termed "optical compliance," is instantaneously and always available for all patients on ventilators without any additional apparatus and thus might improve the assessment of respiratory function in routine care and emergency situations.

Humans↗
PubMed1993

[Monosymptomatic familial Mediterranean fever as the cause of fever of unknown origin].

A previously healthy 2 year old female child developed fever of unknown origin recurring in monthly cycles. The periodic fever attacks, family history and ethnologic criteria were in agreement with familial mediterranean fever, although further more major symptoms were missing. It was highly unusual to find repeatedly raised levels of angiotensin I converting enzyme, a finding previously not described in literature. Excluding any other differential diagnosis by intensive investigations, together with a positive metaraminol provocation test, the diagnosis of a rare, monosymptomatic variant of familial mediterranean fever was proposed. Amyloidosis was excluded by rectal biopsy. Monosymptomatic familial mediterranean fever is very seldom. We suggest to measure routinely angiotensin I converting enzyme for further evaluation of our findings.

Child, Preschool↗
PubMed1991

Scalp heat flux in postmature and in growth-retarded fetuses.

Postterm and growth-retarded fetuses share a common problem which can be characterized by a discrepancy between the supply of oxygen and nutrients to, and the demand of the fetus. But, this "insufficient" placental exchange function may also extend to and affect its thermal homeostasis; e.g. when the capacity of convective (placenta) pathways is shifted towards conductive (surface) pathways for heat loss. Therefore, fetal scalp heat flux measurements, where heat serves as an intrinsic tracer for metabolic activity and placental exchange function, promised a new kind of information. In 81 pregnant women during labor we measured fetal scalp heat flux by means of an heat flux transducer attached to the fetal head and after the cervix had dilated to 3 cm. In the healthy fetuses we found a positive linear relationship between scalp heat flux and different anthropometric variables such as body length (r = 0.432, n = 65, P less than 0.01), head circumference and gestational age. In comparison, postmature and growth-retarded fetuses showed higher heat flux values than appropriately grown fetuses of the same length head size and gestational age. Moreover, in those fetuses scalp heat flux decreased by approximately 4 watt/m2 during the second stage and differed in this regard from the control group who showed stable values during labor and delivery. We conclude that scalp heat flux measurements may indicate disturbances of placental exchange before acute hypoxia occurs.

Adult↗
PubMed1990

Comparison of bedside methods to assess lung mechanics in ventilated neonates: inflation pressure, amount of ventilation and optical compliance versus measured compliance.

Compliance of the respiratory system (CRS) is rarely measured in the critically ill neonate. Instead, inflation pressure (dP), amount of ventilation (dPxfr) and optical CRS are used as indirect parameters to characterize lung mechanics. In 30 randomly chosen newborns ventilated for various causes we investigated which of these bedside methods most accurately represents the compliance of the respiratory system. The correlation coefficient was much higher for the optically determined compliance (r = 0.91) than for the amount of ventilation (r = 0.67) or the inflation pressure alone (r = 0.46) versus the measured static compliance of the respiratory system.

Heart Defects, Congenital↗
PubMed1990

[Heat flux measurements of the fetal scalp and cardiotocography in predicting acidosis states sub partu--a comparison of 2 methods].

Although the efficacy of electronic foetal heart rate (FHR) monitoring and intermittent scalp blood sampling is well established, these methods still result in a considerable number of false positive and negative predictions. Consequently, methods, which improve the accuracy of prediction, are still under study. Heat flux measurements from the foetal scalp have been shown to relate to the metabolic condition of the foetus during delivery. In this study, we investigated the predictive power of measuring scalp heat flux and monitoring the FHR electronically, and the combination of both. In 136 foetuses the scalp heat flux was measured by means of a heat flux transducer, 2.5 cm in diameter, attached to the foetal scalp after the cervix had dilated to greater than 2.5 cm. Heat flux was regarded as abnormal, if the heat flux was less than 10 w/m2 or greater than 21 w/m2, or fell by more than 20% of its initial value during the last 30 min before delivery. FHR tracings were considered abnormal, if they resulted in therapeutic consequences like oxygen mask for the mother, scalp blood sampling or immediate operative delivery. Foetuses were considered acidotic, if their pH in the arterial cord blood was less than 7.20. Accuracy of prediction was described by appropriate parameters. The scalp heat flux method resulted in a higher specificity (80.4% vs. 72.5%), positive predictive value (59.2% vs. 51.7%), and overall accuracy (82% vs. 77%) than FHR monitoring. Sensitivity of FHR monitoring was slightly higher than the one of heat flux method (88.2% vs 85.3%). Combining both methods resulted in a sensitivity of 100% thus detecting all acidotic foetuses, but specificity fell to 62%.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗
PubMed1990

[The school child carrying heavy burdens].

In 163 Viennese pupils in standard 1 to 8, the weight of the schoolbag, the bodyweight and the ratio of these two parameters were examined in order to describe the amount of burden carried by those children. The results were: 1. The weight of the schoolbag war 4.0 kg (range 1 to 9 kg). 2. The pupils carried a schoolbag weighing on the average 10%, in standard 2 about 15% and in standard 8 about 6% of their bodyweight. 3. In every 6th pupil, the weight of the schoolbag constituted more than 15% of the bodyweight. 4. In analogy to pupils in standard 2, adults with a body weight of 70 kg would have to carry a weight of up to 17.5 kg to their working place. 5. While pupils have to carry a burden between 10 and 25% of their bodyweight, adults were carrying only between 1 and 10% of their bodyweight to work. We conclude that pupils are carrying daily a heavy burden in form of a schoolbag and adults apparently don't care about it.

Body Weight↗