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Biomedical subjects

G Litscher

Publications and source records attributed to G Litscher.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effects of acupuncture on the oxygenation of cerebral tissue.

Monitoring of regional cerebral oxygen saturation (r. cereb. O2 satn.) was carried out continuously in 12 healthy subjects (mean age 35.2 +/- 4.4 years; range 26-41 years; 4 women, 8 men), prior to, during and following acupuncture. Measurements were obtained with the INVOS 3100 cerebral oximeter (Somanetics Corp., Troy, USA). In addition new robotic transcranial Doppler sonography (TCD) probes enabling three-dimensional imaging of the middle cerebral artery by the use of multi-scan techniques were used simultaneously. The results showed small increases in r. cereb. O2 satn. mean values (69.9% before, 70.3% during and 70.2% after acupuncture) and a significant (p < 0.01; ANOVA, Tukey test) increase in mean bloodflow velocity during acupuncture measured simultaneously at different depths within the right middle cerebral artery. There are reports in the literature about the effects of acupuncture on the oxygenation of cerebral tissue in a study with animals. An increase in the cerebral oxygen saturation could be registered with the help of microelectrodes in the cortex. This is parallel evidence to the present results with near infrared spectroscopy and transcranial Doppler sonography. Quantifiable changes in the physiological effects of acupuncture may contribute to improved acceptance of this unconventional complementary medical procedure.

Acupuncture Therapy↗
PubMed1998

A multifunctional helmet for noninvasive neuromonitoring.

Simultaneous and continuous recording and processing of different noninvasive neuromonitoring parameters were carried out, including spontaneous and evoked bioelectrical brain activities obtained by new "active electrodes," transcranial Doppler sonographic measurements using robotic probes, a multiscan principle for three-dimensional transcranial Doppler imaging, and recording of near-infrared spectroscopic data. The recording and processing were carried out over periods of some hours with a new recording technique integrated in a helmet construction.

Brain↗
PubMed1998

Transcranial optical spectroscopy--A comparison of the TOS 96 and INVOS 3100 cerebral oximeters.

We evaluated two user-friendly, commercially available transcranial cerebral oximeters (TOS 96, Tostec, Tokyo, Japan and INVOS 3100, Somanetics, Troy, USA) for use in adults. We compared the absolute values (%) of regional cerebral oxygen saturation (rSO2) from 108 measurements in 54 healthy volunteers (31 women, mean age 35.8 +/- 16.3 years and 23 men, mean age 35.4 +/- 9.2 years). The mean rSO2 values obtained by the TOS 96 and INVOS 3100 systems were 72.3 +/- 8.4 % and 72.6 +/- 7.2% respectively. Significant differences (p < 0.01) were found between females and males with the INVOS equipment. The study shows that anatomical (thickness of the skull) and technical (calibration) aspects have to be taken into consideration when interpreting absolute rSO2 values.

Adult↗
PubMed1998

[The artificial heart and neuromonitoring? Technical and clinical aspects].

There is a steady progress in the development of artificial heart and circulatory assist devices. There is also no doubt that further advances in energy systems, materials, and electronics will provide for smaller and more reliable electrically driven blood pumps, but the present engineering design appears to be adequate to provide devices satisfactory for initial clinical use. Due to problems in the availability of suitable donor hearts, the concept of replacing the natural heart with an artificial heart as a "bridge to transplantation" has gained attention in recent years. The present paper shows technical and clinical aspects of multivariable electrophysiologic neuromonitoring in a patient with an artificial heart assist device in the intensive care unit. The data (EEG, 40 Hz brain oscillations, brainstem auditory- and somatosensory evoked potentials) are discussed with respect to the influence of the artificial heart on their quality and reliability. Reasons for artifacts and problems of interpretation are shown.

Artifacts↗
PubMed1998

Robotic transcranial Doppler sonography probes and acupuncture.

The present study shows with a sophisticated quantitative method a change in blood flow velocity in a cerebral artery in response to acupuncture. Monitoring of transcranial Doppler sonography (TCD) was examined in 12 healthy volunteers (mean age: 35.2+/-4.4 years; 26-41 years; 4 female, 8 male) before, during and after acupuncture. In all persons the same unspecific scheme of acupuncture with a "general increase of Qi-energy" was used. The measurements were performed with new robotic TCD-probes allowing three-dimensional imaging by using multi-scan methods. The results showed a significant (p < 0.01; ANOVA; Tukey test) increase in mean blood flow velocity, which was measured at different depths of the right middle cerebral artery. Quantitative determination of the physiological effects during acupuncture can lead to a better acceptance of this unconventional complementary medical method.

Acupuncture Therapy↗
PubMed1997

Inflammatory reactions of the skin caused by adhesive EEG electrodes.

The correct choice of electrodes for neurophysiologic monitoring is one of the unsolved problems in clinical practice and scientific research. In addition to the familiar electrodes, i.e., cup (silver-/silver-chloride, gold) and needle electrodes, adhesive electrodes (e.g., Zipprep electrodes) have been offered for rapid application and accurate signal recording. This case report indicates that adhesive electrodes can lead to superficial lesions of the skin or inflammatory infiltration.

Adhesives↗
PubMed1997

Transcranial cerebral oximetry in the hyperbaric environment.

Continuous monitoring of dynamic changes of transcranial regional cerebral oxygenation (rSO2) was performed in 7 healthy volunteers (mean age 40.9 +/- 12.6 years; range 25-62 years) during normo- and hyperbaric oxygenation (HBO at 2.5 and at 1.95 ATA) using an INVOS 3100 cerebral oximeter. A significant change between HBO and control phase could be found in rSO2, alterations (p < 0.05; ANOVA, Tukey test). The results suggest that the calculation of rSO2 may be a useful method to monitor changes of oxygen saturation under hyperbaric conditions. However, the absolute quantification of rSO2 is useless at the moment and needs further investigation.

Adult↗
PubMed1997

Transcranial cerebral oximetry--is it clinically useless at this moment to interpret absolute values obtained by the INVOS 3100 cerebral oximeter?

Dynamic changes of regional cerebral oxygenation (rSO2) were measured simultaneously to laser Doppler flowmetry in a 35-year-old female during cerebral aneurysm surgery. In addition, to demonstrate the uselessness of the absolute values obtained by the INVOS 3100, cerebral oximeter readings from a pumpkin ("Styrian Cucurbita") are demonstrated. The results of the present study and of other reports discussed in this paper demonstrate that the INVOS 3100 cerebral oximeter should not be used at this moment as a measure reflecting absolute rSO2 values. However, it seems to be relevant that the INVOS 3100 system can monitor the dynamic changes in rSO2, although limitations have to be taken into consideration.

Adult↗
PubMed1997

[Laser Doppler data analysis during interstitial laser thermotherapy with magnetic resonance control within the scope of an animal experiment study].

The aim of the present study was to investigate, using laser Doppler (LD) flowmetry, the phases immediately prior to and following experimental, neurosurgical laser therapy in animals. Two statistical models obtained on the basis of discriminant analysis are described. These models should enable the user to classify the sets of parameters calculated from the LD signals. With both models which contain 3 and 5 parameters, respectively. 100% discrimination of the two phases was attained. The usefulness of the models could be validated by results obtained with other models.

Animals↗
PubMed1997

[Transcranial Doppler ultrasound--robotics-controlled transducers for quantifying the effect of acupuncture].

Transcranial Doppler Sonography (TCD) monitoring was carried out in 12 healthy subjects (mean age: 35.2 +/- 4.4 years; range: 26-41 years; 4 women, 8 men), prior to, during and following acupuncture. In all subjects an identical acupuncture scheme with a "general increase in Qi energy" setting was employed. Measurements were obtained with new robotic TCD probes enabling three-dimensional imaging of the middle cerebral artery by the use of the multi-scan technique. The results showed a significant (p < 0.01; ANOVA; Tukey test) increase in mean bloodflow velocity measured simultaneously at different depths within the right middle cerebral artery. Quantifiable changes in the physiological effects of acupuncture may contribute to improved acceptance of this unconventional complementary medical procedure.

Acupuncture Therapy↗
PubMed1997

Brain-stem auditory evoked potential monitoring. The increase of the stimulus artifact in the development of brain death: a biological phenomenon?

Brain-stem auditory evoked potentials (BAEPs) were recorded in 12 dead subjects (mean age, 72.6 +/- 14.8 years), 30.6 +/- 19.5 hours (range 9-70) after abolished systemic circulation. Death was due to cardiac failure (n = 10), intracerebral hemorrhage (n = 1) and larynx cancer (n = 1). The presence and amplitude of the stimulus artifact were evaluated. The mean (+/- SD) amplitudes of the stimulus artifact was 0.03 +/- 0.02 microV on the left side and 0.01 +/- 0.02 microV on the right side. These findings in accordance with previous studies on comatose patients and brain dead subjects confirm that the increase of the stimulus artifact in the development of brain death, in spite of stimulation with alternating polarity, seems to reflect a biological phenomenon which is not found in dead subjects after complete cessation of systemic circulation.

Aged↗
PubMed1997

Drug induced double peak waveforms in the N20-component of somatosensory evoked potentials.

The double peak waveform of the N20 component of the early somatosensory evoked potentials is a rare finding. In the present paper we investigated 9 patients (mean age +/- SD: 31.3 +/- 11.3 years; range 18-52 years) with the phenomenon of the two subcomponents of the primary cortical complex, after stimulation of the median nerve in a retrospective analysis. The results of the heterogenous patient group showed that the generation of the second subcomponent is not pathognomonic for patients with severe head injury, that it could be reversible and that pharmacological induced effects are presumably responsible for this phenomenon.

Adolescent↗
PubMed1996

Cerebral oximetry in dead subjects.

Near-infrared spectroscopy is a technique used to monitor cerebral oxygenation. To validate the method, we measured regional oxygen saturation (rSo2) in the brains of 18 dead subjects (mean age, 74.4 +/- 14.6 years) 19.8 +/- 18.2 h (range, 1-73) after cessation of systemic circulation, and in 15 healthy probands (mean age, 34.2 +/- 8.7 years) with an INVOS 3100 cerebral oximeter. The mean (+/-SD) rSo2 in the dead subjects was 51.0 +/- 26.8% [range, 6-88%; left, 48.4 +/- 28.0% (n = 21); right, 54.4 +/- 25.7% (n = 16)]. The mean rSo2 in the control group was 68.4 +/- 5.2% (range, 60-76%; left, 68.1 +/- 5.0%; right, 68.7 +/- 5.6%). After removal of the brain at autopsy in five of the dead subjects, the rSo2 was 73.4 +/- 13.3% (15 measurements). Six of 18 of the dead subjects had values above the lowest values found in the healthy adults (> or = 60%). These findings raise concerns about the validity of cerebral rSo2 data in adults obtained by the INVOS 3100 system.

Adult↗
PubMed1996

[Neurophysiologic signal recording. New technical and general practice aspects of EEG recording electrodes].

The problem of electrode selection for neurophysiological monitoring, whether for routine clinical applications or special scientific research, still remains to be resolved. In addition to the classical types of electrode-cup (silver/silver chloride or gold) or needle electrodes, new self adhesive electrodes (e.g. zipprep electrodes) for rapid application and reliable recording have recently come onto the market. However, this electrode type can lead to superficial lesions of the skin or inflammatory infiltration, which so far have not been investigated. New developments in the field of cortex electrodes and so-called active electrodes are additionally discussed.

Cerebral Cortex↗
PubMed1996

[Laser Doppler flowmetry--experiences from intensive care medicine].

Laser Doppler flowmetry makes it possible to determine the status of the microcirculation with the aid of a non-invasive procedure. The present article describes the use in two ICU patients of Doppler laser flowmetry to effect a qualitative and quantitative evaluation of the side effects that may occur when using various stimulation procedures.

Adult↗