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Quantitative thermal sensory and pain threshold testing (QST) was performed in 29 adult healthy volunteers (mean age 24.2 +/- 2.7 years; range: 18-29 years; 20 females, 9 males) using the Thermal Sensory Analyser TSA-II (Medoc Advanced Medical Systems, Ramat Yishai, Israel, and Minneapolis, Minnesota, USA) before and after laser needle acupuncture and placebo stimulation, respectively. Significant (p < or = 0,001; t-test) gender-specific differences were seen on cold pain threshold analysis. No significant changes in parameters of thermal sensory and pain thresholds were found before and after laser needle or placebo stimulation at acupuncture points for acute pain. However, a trend towards change in the median value of cold pain sensation after laser needle stimulation (p = 0.479; paired t-test; n.s.) was seen within the group of healthy females. The influence of stimulation of acupuncture points for chronic pain on the various parameters needs to be clarified in future studies.

In an experimental animal study (Sus scrofa domesticus) we investigated the effects of the new technique of laser needle stimulation (wavelength: 685 nm; energy density: 4.6 kJ/cm2 per point; application duration: 20 min). The results revealed changes in microcirculatory parameters of the skin resulting in an increase in blood flow. However, the quality and intensity of the laser light did not induce micromorphological alterations in the skin.

Near-infrared spectroscopy (NIRO 300, Hamamatsu Photonics, Japan) was used to monitor human cerebral function in the central region during manual acupuncture needle stimulation of the large intestine 4 (LI.4) point in 16 adult volunteers (9 females, 7 males; mean age 23.9 +/- 6.0 (SD) years, range 19-45 years). We found a significant (p < 0.001) decrease in oxyhaemoglobin after needle insertion and stimulation (duration 20 sec.), accompanied by an increase (p = 0.003) in deoxyhaemoglobin. A repeat stimulation showed similar effects. Cytochrome oxidase aa3 remained unchanged during stimulation. The results demonstrate that near-infrared spectroscopy may be a noninvasive method of measuring regional changes in cerebral haemodynamics resulting from peripheral acupuncture stimulation.

Continuous microcirculation monitoring of the right foot was carried out for the first time in a 62-year-old patient with cryoglobulinaemia prior to, during and after manual needle insertion at Jie Xi(St.41) acupuncture point using a new method of laser Doppler perfusion imaging (PIMII, Lisca AB, Linköping, Sweden). In addition to visual inspection, changes in mean perfusion were also used as evaluation parameters. Our results suggest that the new biomedical technique of laser Doppler imaging is a useful method for monitoring the effects of acupuncture on the peripheral microcirculation.

For the first time, we have studied the effects of manual acupuncture and of laser puncture on cerebral oxygenation in three healthy male volunteers using transcranial near-infrared spectroscopy (NIRO 300, Hamamatsu Photonics, Japan). The results indicate that acupuncture of specific acupuncture points leads to an increase in oxygenated haemoglobin and in the tissue oxygenation index. However, needling and laser puncture at placebo points does not produce the same effect on cerebral oxygenation. This fact provides further proof of specific quantifiable effects of acupuncture on the brain.

Using infrared thermography, the present study evaluated the effects of changes in peripheral perfusion occurring during the initial phase of manual acupuncture (Nei Guan, Qu Chi) under standardised conditions. Thermographic recordings (AGEMA 570 PRO, Flir Systems Inc., Portland, USA) were used to assess superficial changes in temperature in the hands of 6 normal subjects (mean age 33.3 +/- 7.5 years, 3 females, 3 males). Baseline status, acupuncture needling and stimulation were analysed in a single session under controlled conditions (24 degrees C ambient temperature). In all subjects a significant (p = 0.015) short-term cooling effect on superficial hand temperature occurred following needle placement. Thereafter, acupuncture stimulation produced different generalised long-lasting effects. In three subjects a warming effect was seen (increase > 2 degrees C) while in the other three subjects the temperature decreased in all fingers and in the wrist.

Acupuncture has been used for over 5,000 years and a large body of evidence exists. Transcranial Doppler (TCD) ultrasound, introduced more than a decade ago, has evolved into a dynamic, reliable, reproducible and practical diagnostic tool. In this study we describe simultaneous and continuous TCD monitoring of the supratrochlear and middle cerebral arteries in two patients with ophthalmologic diseases undergoing computer-controlled acupuncture (CCA). During eye acupuncture scheme there was a significant increase in the mean bloodflow velocity (vm) of the A. supratrochlearis (+39% patient 1; +15% patient 2; p < 0.001, t-test) in both patients. The effect was still evident after the needles were removed. There was a smaller increase (+4% and +3%; n.s.) of vm in the A. cerebri media. These results suggest that eye acupuncture could have a specific effect on intra- and extracerebral arteries. CCA might improve the quality of acupuncture.

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.

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.

Since its introduction into the clinical setting at the beginning of the 'eighties, transcranial Doppler sonography (TCD) has gained increasing acceptance as a non-invasive neuromonitoring technique. The ability of TCD to detect embolic particles within the cerebral blood vessels has been the subject of intensive investigation in recent years. In the present paper, a new method for the detection of emboli (multirange principle), intra-operatively during a neurosurgical intervention in a 35-year-old patient with a tumour in the posterior fossa and an open foramen ovale, is described for the first time. The method opens up new possibilities for the intra-operative management and the rapid assessment and diagnosis of paradoxical cerebral embolism.

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.

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.

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.

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.

In the present paper, experience with the detection of burst suppression in the pEEG is described. The possibilities and limitations of the method during monitoring of anaesthesia under real conditions are discussed.

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.

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.

To ensure efficient computer-based cerebral monitoring in the ICU and during anaesthesia, sophisticated and sometimes expensive equipment is needed. It is thus all the more important that the clinician should have a good understanding and knowledge of the various methods involved, the origins of the different signals and their relationships, and of the possibilities of artefacts occurring, if the information that this equipment is capable of providing is to be fully and properly utilized. The present paper describes a number of new techniques of cerebral monitoring, and their successful application in the intensive care unit and the operating theatre.

Laser Doppler flowmetry (LDF) is a noninvasive method to study the microcirculation. We studied the feasibility of the clinical use of LDF in the intensive care unit by continuously recording different LDF parameters during the cessation of cerebral and cardiocirculatory function. The LDF-Conc (concentration of red blood cells) reflected biological phenomena correlated with the heart rate and microvibration that could not be detected with conventional means (systemic blood pressure, peripheral oxygen saturation).

Near infrared spectroscopy is a non-invasive method of calculating changes in cerebral oxygenation. We have now evaluated a new near infrared spectroscope, the NIRO-500 (Hamamatsu Photonics, Japan), in an intensive care unit setting. The influence of extracerebral and intracerebral physical-technical, physiological and pathophysiological parameters was investigated. The results showed that the method is very sensitive to changes in oxygenation and perfusion in the cerebral vasculature. However, the influence of other factors can be considerable and not always easy to detect and interpret.

Regional cerebral oxygen saturation (rSO2) was studied in 15 healthy volunteers aged between 23 and 53 years (mean age: 34.2 +/- 8.7 years) and in 17 intensive care patients (mean age: 37.2 +/- 18.6 years; range 17-70). An infrared spectroscopy technique (INVOS 3100, Somanetics Co.) was used. The results were analysed in terms of age, heart rate, temperature at the recording site, blood pressure and peripheral oxygen saturation. The mean +/- SD of rSO2 was 69.4% +/- 7.0% in the healthy volunteers and 66.4% +/- 7.4% in intensive care patients (65.3% +/- 6.2% in 7 patients with a cerebral lesion, 67.1% +/- 8.4% in 10 patients with no cerebral lesion). Individual examples are presented to show that infrared spectroscopy is a useful non-invasive method of investigating cerebral oxygenation. However, regional pathological-anatomical limitations of the technique, and possible extracerebral artefacts make necessary a critical interpretation of the rSO2 values.

Heart rate variability and thoracal respiratory movements were examined in two babies aged six months during eight hour polysomnographic recordings. Computer-assisted analysis in the time and frequency domain were performed to investigate the mechanisms underlying cardiorespiratory control. Coherence and phase relation between cardiac cycles and respiration were investigated in detail. Both methods demonstrated that during quiet sleep (stage 3/4), the cardiorespiratory coupling was significantly increased as compared to active sleep (REM sleep).

The effects of orthotopic heart transplantation on spontaneous fluctuations of the respiration rate and heart rate were studied with a computer-assisted system for neurovegetative monitoring in 22 patients (mean age +/- SD: 48.7 +/- 9.4 years) 19.5 +/- 14.4 months after transplantation. The control group consisted of 12 healthy volunteers (mean age +/- SD: 38.7 +/- 6.6 years). The mean (+/- SE) respiratory rate was higher in the transplantation group than in the control group (17.7 +/- 0.8/min vs. 14.6 +/- 1.1 breaths/min, P < 0.2). The mean variability of the respiratory rate was smaller in the transplant patients than in the controls (3.7 +/- 0.3 vs. 2.8 +/- 0.4, P < 0.2). The heart rate variability coefficient in the patients after transplantation was lower than that in the controls (1.3 +/- 0.1% vs. 6.9 +/- 0.5%, P < 0.001). Spectral analysis of heart rate variability showed a smaller decrease of variability of respiration (P < 0.05) than of blood pressure regulation (P < 0.001) or of the angiotensin-renin system (P < 0.001). A separate group of 7 transplant patients (mean age 51.0 +/- 7.7 years) had activated cardiac pacemakers and thus no spontaneous physiologic heart rate oscillations. The variability of the respiratory rate in these patients was lower than in the other 22 transplant patients (1.8 +/- 0.2 vs. 3.7 +/- 0.3, P < 0.001). The data provided by multiparametric neurovegetative monitoring support the evaluation of complex regulatory mechanisms of respiratory and cardiovascular function and their adaptability after orthotopic heart transplantation.

Polysomnographic recordings were made in 10 healthy male adult subjects (mean age 25.1 +/- 2.8 years). Parameters were obtained from continuous non-invasive measurement of blood pressure and from heart rate spectra analysed both in the waking state and during sleep (stage 4). The total heart rate variability (mean +/- SE) was not significantly diminished (p < 0.2; paired t-test) during stage 4 sleep (6.2 +/- 0.5%) as compared with the waking state (7.1 +/- 0.5%). The relative heart rate variability coefficient within the frequency band HRV-II ((3-9)/min) was, however, significantly higher (p < 0.001) during slow-wave sleep (0.55 +/- 0.04) than during wakefulness (0.34 +/- 0.04). This fact is in accordance with results concerning an estimated value of the baroreflex sensitivity, which was also significantly higher (p < 0.001) during sleep stage 4 (7.0 +/- 0.8 ms/mmHg vs. 10.4 +/- 1.4 mmHg).

Simultaneous continuous recording and processing of evoked potentials, various cardiovascular, and respiratory signals was realized with the aid of a PC-controlled monitoring system. The system is at present used for monitoring patients in intensive care units, during neurosurgical interventions and for sleep investigations in infants.

A computerized, PC-based system is introduced for sleep monitoring in infants. The system is capable of digitizing and storing 22 physiological variables over a whole-night sleep period. The preprocessed data can be displayed on a single page; further processing can be done on the digitally stored data.