Birgit Steuernagel

Cerebral autoregulation during whole-body hypothermia and hyperthermia stimulus

The purpose of the study contained herein was to investigate the effects of old traditional physiotherapeutic treatments on cerebral autoregulation. Treatment consisted of complete body immersion in cold or warm water baths. Fifteen volunteers were investigated by means of transcranial Doppler sonography and a servo-controlled noninvasive device for blood pressure measuring. One group of 8 volunteers (mean age, 27.2+/-3.5 yr; gender, 3 females/5 males) was subjected to cold baths of 22 degrees C for 20 min Another group of 7 volunteers (mean age, 52.1+/-8.5 yr; gender, 4 females/3 males) took hyperthermic baths at rising water temperatures from 36 degrees to 42 degrees C, increased by 1 degree C every 5 min. Each volunteer in both groups underwent autoregulation tests two to four times before, during, and after the thermic bath. Dynamic autoregulation was measured by the response of cerebral blood flow velocity to a transient decrease of the mean arterial blood pressure, induced by rapid deflation of thigh cuffs. The autoregulation index, i.e., a measure of the speed of change of cerebral autoregulation, was used to quantify the response. Further parameters were core temperature, blood pressure (mm Hg) and CO2et. During hypothermic baths, core temperature decreased by 0.3 degrees C (P = 0.001), measured between preliminary phase and the end of the bath; the autoregulation index decreased significantly (P < 0.05) from 5.3 before the bath to 4.25 during the bath. During hyperthermic baths, the autoregulation index increased from 6.0 to 7.5 and 8.9 (P < 0.001), with an increase of core temperature of 0.4 degrees C. The main cerebral autoregulation system is dependent on changes of core temperature, provoked by hypothermic or hyperthermic whole-body thermostimulus. Application of hyperthermic baths increased the autoregulation index, and hypothermic baths decreased the autoregulation index. Further studies are needed to prove the positive effects of thermo-stimulating water applications on cerebral hemodynamics in patients with cerebral diseases.

External stimuli in the form of vibratory massage after heart or lung transplantation.

Manual vibratory massage is part of the preventive physiotherapeutic activities performed in intensive care units. The vibratory massage can be performed manually or as electrovibratory massage. The manual massage is a fast rhythmical vibration performed by the arm and shoulder muscles of the masseur and transferred to the patients thorax by the hand. The hand of the masseur has to achieve a tremor with a frequency of 8 to 11 tremors/s. The aim of the pilot study was to examine the influence of manual vibratory massage on the pulmonary function of postoperative patients who were receiving mechanical ventilation, with special interest being focused on pulmonary ventilation and perfusion and cerebral blood flow velocity. Manual vibratory massage was performed postoperatively in the intensive care unit on eight patients: three patients had undergone heart transplantation, three had undergone lung transplantation, and two had undergone coronary artery bypass grafting (mean age, 53.6+/-8 yr). With the aid of continuous monitoring, we examined the changes of the respiration parameters and the cerebral blood flow velocity (measured by transcranial Doppler sonography). The vibratory massage was performed with a frequency of 8 to 10 vibrations/s for 15 min, 7.5 min on each side of the thorax, starting from the lower costal arch and progressing to the upper thoracic aperture. For 10 min before, during, and 10 min after the massage, the parameters of peripheral oxygen saturation, central venous pressure, mean arterial pressure, heart rate, lung resistance and compliance, tidal volume, respiration rate, and cerebral blood flow velocity were recorded at 2-min intervals. Moreover, before and after vibratory massage, arterial blood gases were determined. In four of the eight patients, it was possible to determine pulmonary arterial pressure, pulmonary capillary wedge pressure, as well as pulmonary vascular resistance. During the vibratory massage, we could prove a significant increase of the mean tidal volume by 30% (P = 0.008). The percutaneous oxygen saturation significantly increased also, from 92 to 93.6% (P = 0.002). Central venous pressure significantly decreased by 11% (P = 0.04), and pulmonary vessel resistance was reduced by 18.3% (P = 0.001). The pulmonary resistance decreased from 10.5 to 9.2 H2O/l/s (P < 0.05) by the end of the observation period. Cerebral blood flow velocity showed no significant change. Vibratory massage seems to improve pulmonary mechanism and perfusion, thus, reducing ventilation perfusion mismatch and increasing oxygen saturation.

Veränderung kognitiver Hirnleistungen im Alter durch Kneipp-Anwendungen

Changes of Cognitive Brain Functions in the Elderly by Kneipp Therapy Introduction: Pharmacological and nonpharmacological treatment of brain syndrome is multifarious. Until now, plain external applications of physical stimuli, as used daily in geriatric care, were not explored regarding their influence on cognitive brain function.The aim of this randomized cross-over study was to examine the influence of dermatoreceptive stimuli on cognitive brain function of healty geriatric volunteers. Methods: 24 healthy volunteers (23 women, 1 man) were randomized into 2 groups (cross-over design). Group A (mean age ± SD: 68.8 ± 6.2 years) was treated according to the following regime: at first a 10–12 °C cold stimulus for 10 s (a so-called Kneipp face shower) and afterwards a cold wet pack of 10–12 °C at the neck for 1 min. Group B (age 69.8 ± 5.3 years) was subjected to an identical procedure but with warm thermoindifferent temperatures of 34–36 °C. After 1 week the two groups were interchanged. The parameters of interest were the critical flicker frequency (CFF) and the latencies of the event-related P300 potentials of the visually evoked potentials (VEP), which can be considered the electroencephalographic substrate of the cognitive functional ability. The CFFs and the P300 latencies and amplitudes were measured directly before and 10 min after the application of the above-mentioned stimuli. Furthermore, the CFFs were recorded a second and third time 30 and 60 min later. Results: Following application of cold-water stimuli, the CFF increased from (mean ± SE) 32.55 ± 0.44 s-1 to 33.06 ± 0.44 s-1 (p = 0.003) 10 min after the stimulus. 30 min later the CFF was still elevated at 32.95 ± 0.47 s-1 (p = 0.043). The P300 latencies decreased by 4.8% (p < 0.001) after cold-water application from 266.5 ± 5.28 to 253.7 ± 4.22 ms. After warm stimuli they increased from 258.69 ± 3.71 to 266.17 ± 5.03 ms (p = 0.01). The P300 amplitudes were elevated by 5% only with the cold stimuli (p = 0.004). Conclusion: Cold water applied locally to face and neck region is able to provoke significant improvements of cognitive abilities.

Zerebrale Hämodynamik während der Implantation von Kardioverter-Defibrillator-Systemen

Zusammenfassung□ GrundproblematikBei der Implantation von automatischen implantierbaren Kardioverter-Defibrillatoren (ICD) muß zur Ermittlung der Funktion und der optimalen Reizschwelle Kammerflimmern induziert werden, das einen Kreislaufstillstand und somit auch ein Sistieren der Hirndurchblutung verursacht. Ziel der vorliegenden Studie war es, bei induziertem Kammerflimmern die Veränderungen der zerebralen Blutflußgeschwindigkeit (CBFV(MCA)) in Abhängigkeit von der Länge der Fibrillationszeit und der Ausgangshöhe der CBFV(MCA) zu untersuchen.□ Patienten und Methodik60 induzierte Episoden von Kammerflimmern wurden bei neun Patienten (53,5±8 Jahre alt) während der ICD-Implantation untersucht. Zusätzlich zum anästhesiologischen Monitoring wurde zur Messung der zerebralen Blutflußgeschwindigkeit die transkranielle Doppler-Sonographie (TCD) in der Arteria cerebri media (MCA) eingesetzt. Die Dauer der Fibrillation sowie die Höhe und Dauer der CBFV(MCA)-Erhöhung in der postdefibrillatorischen Phase wurde einer Korrelationsrechnung und linearen Regression unterzogen. Außerdem wurde untersucht, ob systematische Unterschiede zwischen den verschiedenen Episoden eines Patienten bestehen (Zeittrend), wozu jeweils fünf aufeinanderfolgende Episoden verglichen wurden.□ ErgebnisseWir fanden bei allen Episoden in der postdefibrillatorischen Phase eine Hyperperfusion, das heißt ein Zeitintervall, in dem die Meßwerte der CBFV über dem vor der Fibrillation gemessenen Ausgangswert lagen. Für die Hyperperfusionsdauer ergab sich eine signifikante Abhängigkeit von der Fibrillationszeit (r=0,57; p<0,001). Die Regressionsgleichung lautet: Hyperperfusionsdauer=11,1+1,22×Fibrillationszeit. Die Hyperperfusionshöhe, das heißt die maximale CBFV nach Defibrillation, steigt mit der CBFV(MCA) vor der Fibrillation signifikant an (r=0,88; p<0,001), wobei die Regressionsgleichung lautet: Hyperperfusionshöhe=6,11+1,22×CBFV vor Fibrillation. Die Hyperperfusionsdauer wird nicht von der maximalen CBFV(MCA) nach der Defibrillation beeinflußt (r=0,08; p=0,52). Es ergaben sich keine signifikanten Unterschiede zwischen den verschiedenen Episoden eines Patienten hinsichtlich der Hyperperfusionsdauer und der maximalen CBFV nach Defibrillation.□ SchlußfolgerungNach einer induzierten ventrikulären Fibrillation ist immer eine reaktive zerebrale Hyperperfusion zu erwarten. Die Höhe der CBFV nach Defibrillation ist von der Höhe der CBFV vor der Fibrillation abhängig und verhält sich annähernd proportional zu dieser. Die Hyperperfusionsdauer (im Mittel 25,8±10,4 s) zeigt bei den von uns gemessenen Fibrillationszeiten (12±4,8 s) eine lineare Abhängigkeit von der Fibrillationsdauer. Dies gibt einen Hinweis darauf, daß es sich hier um Fibrillationszeiten handelt, bei denen sich die zerebrale Autoregulation und andere zerebrale Regulationsmechanismen reaktiv kompensierend auf die zerebrale Blutflußgeschwindigkeit auswirken. Ob der Hirnstoffwechsel ein ähnliches Verhalten zeigt wie die CBFV, ist Gegenstand weiterer Untersuchungen.Abstract□ ObjectiveDuring ICD-implantation it is necessary to prove the function and to determine the optimal threshold by means of induced ventricular fibrillation (VF). Provoked cardiac arrests cause a circulatory stop of the cerebral perfusion. Our aim was to examine the changes of cerebral blood flow velocity (CBFV(MCA)) after induced VF depending on the duration of fibrillation and prior values of CBFV(MCA).□ Patients and MethodsSixty induced episodes of VF in 9 patients (mean age±SD 53.5±8 years) were examined during ICD-implantation. Beside the standardized anaesthesiological monitoring, transcranial Doppler sonography was used to record the cerebral blood flow velocity in the middle cerebri artery CBFV(MCA). The duration of the fibrillation-period and the range and duration of the CBFV increase during the post defibrillation-period were correlated. Additionally, we examined whether systematic differences existed between the episodes of each patient (time-trend) by means of 5 following episodes of a patient.□ ResultsDuring all episodes of VF a hyperperfusion was present, that means a time intervall showing increased values of CBFV(MCA), compared to the values present before VF. The duration of hyperperfusion depended significantly on the fibrillation time (r=0,57; p<0,001). The equation of regression is: hyperperfusion time =11,1+1,22×fibrillation time. The amount of hyperperfusion, that means the maximal CBFV after defibrillation, increased significantly with CBFV(MCA) before VF (correlation=0,88; p<0,001). The equation of regression is: hyperperfusion height=6,11+1,22×CBFV(MCA) before VF. The duration of hyperperfusion is not influenced by the maximal CBFV(MCA) after defibrillation (r=0,08; p=0,52). In the examined patients no significant differences in the hyperperfusion time and maximal CBFV(MCA) after defibrillation between the episodes were found.□ ConclusionAfter induced VF you always have to expect a reactive cerebral hyperperfusion. The amount of increase of CBFV after defibrillation depends on the prior values of CBFV before fibrillation and shows a nearly proportional relation to these. The duration of hyperperfusion shows a linear dependency on VF-times. This may show that we had VF-times, in which the cerebral autoregulation and other cerebral physiological reactions compensate the drop of the CBFV(MCA) during VF in the postfibrillation time. In further studies will be examined if there are similar changes in the cerebral metabolism as in CBFV(MCA).

Wirkungen kinetischer Stimuli auf die zerebrale Hämodynamik und den zerebralen Stoffwechsel am Beispiel von aktiven und passiv ausgeführten Bewegungen

Effects of Active and Passive Movement Stimuli on Cerebral Hemodynamics and the Cerebral Metabolism Introduction: In contrast to the well-examined cardiovascular changes during movement stimuli, up to now changes of cerebral hemodynamics and cerebral metabolism have rarely been studied. We investigated the question if active and passive movement stimuli cause changes in the cerebral hemodynamics and the cerebral metabolism. Method: Active and passive repetitive movement stimuli on 14 volunteers (8 females, 6 males, age 35 ± 8 years) were examined. As a parameter of cerebral hemodynamics the mean and the peak blood flow velocity (mCBFVMCA, pCBFVMCA) in the middle cerebral artery (MCA) were recorded by transcranial Doppler sonography. At the same time the noninvasive blood pressure (Penaz method) and the CO2 expiration concentration were investigated on 8 volunteers of the collective. As cerebral metabolic parameters we examined in 4 volunteers additionally the cerebral respiratory chain enzyme cytochrome aa3 (ccytaa3) and the cerebral oxygen saturation (cHbO2) by the transcranial near infrared spectroscopy. With each volunteer 4 measurement series were carried out with a special active and passive exercise program for the right upper as well as the right lower extremity. Each measurement series was formed according to the evoked flow test (R. Aaslid): Exercises were carried out for 20 s, followed by a break of 20 s; this was repeated 10 times for each series. Results: During active exercises of the right lower extremity we found an increase of 13.6% (p < 0.001) of pCBFVMCA and an increase of 3.8% (p = 0.003) of mCBFVMCA. During passive exercises of the lower extremity the increases ran up to 12.3% (p < 0.001) for pCBFVMCA and 3.4% (p = 0.004) for mCBFVMCA. The increases of pCBFVMCA came up to 12.5% (p < 0.001) at active exercises of the right upper extremity, those of mCBFVMCA to 3.5% (p = 0.15). During passive exercises of the upper extremity the pCBFVMCA increased by 12.2% (p < 0.001) and the mCBFVMCA by 4.6% (p = 0.007). Significant increases of ccytaa3 were measured during active exercises of the upper extremity (1.6%; p = 0.04) and of the lower extremity (2.7%, p = 0.007). We also found an increase of ccytaa3 during passive exercises of the upper extremity (1.5%, p = 0.04). Significant changes of cHbO2 were measured with 2.5% (p < 0.05) at active exercises of the lower extremity. Conclusion: These studies show that active as well as passive clinical exercises cause an increase of cerebral blood flow velocity. We attribute the increase of cerebral hemodynamics and cerebral metabolism to cerebral activation and autoregulative mechanisms.

Literaturübersicht zu aktuellen Forschungsergebnissen zum positiven Effekt von Bewegungstherapie bei chronischer Herzinsuffizienz

Review of Literature on Results of the Latest Research on the Positive Effect of Exercise Therapy in Chronic Heart Insufficiency Scientific investigations indicate similarities in the pathophysiology of heart insufficiency and that of physical inactivity: similar changes in peripheral hemodynamics (increased peripheral vascular resistance, worsening of oxygen utilization during exercise), in autonomic control (activation of neurohumoral compensatory mechanisms, e.g. the renin-angiotensin system, overactivation of the sympathicus, reduction of vagal tonus, reduced pressosensitivity), in functional activity (reduced exercise tolerance and reduced maximum oxygen uptake), in skeletal muscle (decrease in mass, changes in structure), and in the psychological state (reduction in activity and feeling of well-being). In several, although small-scale studies it could be shown that patients with advanced left ventricular failure were able to take part in training programs without experiencing any ill effects, and that there was a positive shift in the usual typical effects of physical training, such as increase of heart rate, change in respiratory frequency, and maximum oxygen uptake. It could be shown that exercise therapy can result in a shift in the balance between the sympathetic and the parasympathetic tonus in the low- and high-frequency maxima of the R-R interval variability. The pre-training general predominance of the sympathetic tonus over the vagal tonus was changed dramatically by the training, leading to a predominance of the vagal tonus. Recent controlled studies with a randomized and controlled cross-over design and the application of a training program which was carried out regularly and independently have confirmed the positive effect of aerobic fitness training in cases of heart disease. At the end of the exercise phase, the patients experienced a significant improvement of the symptoms of left ventricular failure and of their capacity for exercise; furthermore, the training altered parts of the neurohumoral activation, which count as the main factors in the progression and death rate of patients with chronic cardiac disease.

Zerebrale Hämodynamik bei Kohlendioxidapplikationen

Cerebral Hemodynamics in Carbon Dioxide Applications Introduction: We compare the effect of carbon dioxide (CO2) dry and wet applications on cerebral hemodynamics. Methods: On 22 volunteers measurements were taken during CO2 application. 10 probands were examined in CO2 wet application (1,100–1,300 mg/l) and 12 probands in CO2 dry application (500 g in a 800 l bathtub). The cerebral blood flow velocity (CBFV) in the middle cerebri artery (MCA) was measured as a parameter of cerebral hemodynamics by means of transcranial doppler sonography. Furthermore were recorded CO2 expiratory concentration (CO2et), blood pressure, and sublingual temperature. Results: At CO2 wet application the CBFV increased during therapy phase by 15% (p = 0.001), parallel to the rise of the CO2et by 18% (p = 0.01). During CO2 dry application CBFV decreased by 11% (p = 0.007), body temperature increased significantly by 0.2 °C. Conclusion: CO2 applications have influence on cerebral hemodynamics. Assuming constant diameters of the great brain vessels, CO2 wet application shows a raising and CO2 dry application a reducing influence on cerebral blood flow. This influence will attain therapeutic relevance.

Pilot-Senffussbad-Studie unter besonderer Berücksichtigung der zerebralen Blutflussgeschwindigkeit

Pilot Study on Mustard Footbaths Especially Considering Cerebral Blood Flow VelocityIntroduction: Mustard, especially Sinapis nigra, has been known as medicinal plant since former times and was considered as ‘sucking out’ and ‘brain purifying’. Later Hufeland used mustard seeds chiefly for external applications in form of baths, plasters, and compresses H. Krauss described the use of Sinapis nigra for asthmatical troubles and different forms of cephalgia. Objective: The pilot study presented here starts from the hypothesis that footbaths with Sinapis nigra cause changes in cerebral blood flow velocity (CBFV). Methods: We measured CBFV in the Arteria cerebri media by means of transcranial Doppler sonography, furthermore arterial blood pressure (ABP), carbon dioxide expiratory concentration (CO2ex), respiratory frequency, arterial oxygen saturation (SaO2), digital pulse, and body temperature. The verum group and the comparative group consisted of 5 healthy probands each (3 male, 2 female, mean age 27.5 years). Results: The application of footbaths with black mustard showed a significant reduction of CBFV (5.5–8%) in comparison to pure-water foot baths. Till now this change of CBFV cannot be explained, as neither ABP nor CO2ex changed. Conclusion: There initial examinations can give an indication of the mode of action of footbaths with Sinapis nigra, in accordance with the experience of physicians and patients using this form of application for chronical cephalgias. Further studies with a larger number of patients and probands will give more information on the observed physiological changes.