Christoph Janke

Intestinal ischaemia during cardiac arrest and resuscitation: comparative analysis of extracellular metabolites by microdialysis

Intestinal ischaemia is a major complication of shock syndromes causing translocation of bacteria and endotoxins and multiple organ failure in intensive care patients. The present study was designed to use microdialysis as a tool to monitor intestinal ischaemia after cardiac arrest and resuscitation in pigs. For this purpose, microdialysis probes were implanted in pig jejunal wall, peritoneum, skeletal muscle and brain, and interstitial fluid was obtained during circulatory arrest (induced by ventricular fibrillation) and after return of spontaneous circulation (ROSC). Cardiac arrest for 4 min caused a prolonged (60 min) reduction of blood flow in jejunal wall, muscle and brain as determined by the ethanol technique. This was accompanied by cellular damage in heart muscle and brain as indicated by increased levels of troponin-I and protein S-100, respectively. Plasma levels of glucose, lactate and choline were increased at 15-60 min following cardiac arrest. In contrast, cardiac arrest induced a rapid but variable decrease of interstitial glucose levels in all monitored organs; this decrease was followed by an increase over baseline during reperfusion. In the intestine, lactate, glutamate and choline levels were increased during ischaemia and reperfusion for 60-120 min; intestinal and peritoneal samples yielded parallel changes of lactate levels. Brain and muscle samples showed similar changes as in intestinum and peritoneum except for glutamate, which was increased in brain but not in muscle. We conclude that intestinal ischaemia occurs as a consequence of cardiac arrest and resuscitation and can be monitored by in vivo microdialysis. Comparative analysis by multi-site microdialysis reveals that the intestine is equally or even more sensitive to ischaemia than brain or muscle.

Bispectral Index Monitoring and Seizure Quality Optimization in Electroconvulsive Therapy

In ECT, the relative timing of seizure induction and anesthesia may critically impact on seizure quality when anesthetic agents with anticonvulsive properties such as barbiturates or propofol are used. Measuring the depth of anesthesia by bispectral index (BIS) monitoring and thereby identifying the optimal moment for seizure induction might enhance seizure quality.Seizures from 869 individual ECT -sessions with thiopental anesthetic from 118 patients were examined in this retrospective study. The associations of the BIS value at the moment of seizure induction with 7 established seizure parameters and with a novel model of seizure quality were tested by regression analyses.BIS value at induction correlated positively with seizure duration, central inhibition, coherence and maximal heart rate, but not with midictal amplitude. Higher seizure quality was related with a higher BIS value at the moment of seizure induction.The BIS value at seizure induction serves as an independent predictor of seizure quality, influencing most other established markers. BIS monitoring appears as a simple tool to identify the optimal moment for seizure induction.

Hypertonic-Hyperoncotic Solutions Reduce the Release of Cardiac Troponin I and S-100 After Successful Cardiopulmonary Resuscitation in Pigs

UNLABELLED In some patients, cardiopulmonary resuscitation (CPR) can revive spontaneous circulation (ROSC). However, neurological outcome often remains poor. Hypertonic-hyperoncotic solutions (HHS) have been shown to improve microvascular conductivity after regional and global ischemia. We investigated the effect of infusion of HHS in a porcine CPR model. Cardiac arrest was induced by ventricular fibrillation. Advanced cardiac life support was begun after 4 min of nonintervention and 1 min of basic life support. Upon ROSC, the animals randomly received 125 mL of either normal saline (placebo, n = 8) or 7.2% NaCl and 10% hydroxyethyl starch 200,000/0.5 (HHS, n = 7). Myocardial and cerebral damage were assessed by serum concentrations of cardiac troponin I and astroglial protein S-100, respectively, up to 240 min after ROSC. In all animals, the levels of cardiac troponin I and S-100 increased after ROSC (P < 0.01). This increase was significantly blunted in animals that received HHS instead of placebo. The use of HHS in the setting of CPR may provide a new option in reducing cell damage in postischemic myocardial and cerebral tissues. IMPLICATIONS Infusion of hypertonic-hyperoncotic solutions (HHS) after successful cardiopulmonary resuscitation in pigs significantly reduced the release of cardiac troponin I and cerebral protein S-100, which are sensitive and specific markers of cell damage. Treatment with HHS may provide a new option to improve the outcome of cardiopulmonary resuscitation.

New evidence for seizure quality improvement by hyperoxia and mild hypocapnia.

Introduction Preoxygenation and hyperventilation (with oxygen) in electroconvulsive therapy (ECT) may improve not only safety but also seizure quality. Methods We retrospectively examined transcutaneous tissue partial pressure of oxygen (tcpO2) and carbon dioxide (tcpCO2) in 441 ECT sessions of 37 consecutive patients. All patients received standard face mask airway management. In parallel, seizure quality markers such as seizure duration, seizure amplitude, central inhibition, interhemispheric coherence, and sympathetic activation were documented and used to build up a seizure quality sum score. Results Mean (SD) tcpO2 was 289 (123) mm Hg and for tcpCO2 41 (11) mm Hg. A multivariate repeated measurement regression analysis revealed that the ratio of tcpO2/tcpCO2 had a significant influence on the seizure quality sum score (P = 0.033). Furthermore, a corresponding regression analysis with charge (“stimulation energy”) as a dependent variable showed a significant influence of tcpO2 (P = 0.019) and of tcpO2/tcpCO2 (P = 0.03), too. Conclusions We observed, in our typical clinical ECT sample of 37 patients, a significant and synergistic influence of tcpO2/tcpCO2 on seizure quality. Partial pressure of oxygen covaried with lower stimulation energy. The ratio tcpO2/tcpCO2 was associated with lower stimulation energy and still better seizure quality.

Preliminary evaluation of clinical outcome and safety of ketamine as an anesthetic for electroconvulsive therapy in schizophrenia

Abstract Objectives. Electroconvulsive therapy (ECT) is an effective and safe option in the treatment of affective disorders and schizophrenia. One parameter known to influence ECT treatment efficacy is the choice of narcotic, and ketamine has emerged as an interesting alternative to conventional anaesthetics like barbiturates since it does not negatively influence seizure threshold. However, due to the potential to provoke dissociative symptoms, ketamine anaesthesia is rather hesitantly used in schizophrenia patients for fear of causing disease exacerbation. Methods. We retrospectively investigated clinical outcome and safety in patients treated with ECT for schizophrenia and receiving ketamine anaesthesia, either exclusively or as switch from another narcotic and compared seizure parameters to a group of ECT-treated schizophrenia patients with thiopental anaesthesia. Results. In none of the six patients undergoing ECT with ketamine did we observe disease exacerbation, and except for one patient, all patients responded or remitted under ECT. A preliminary analysis of seizure parameters shows an association with longer seizures in patients exclusively receiving ketamine. Conclusions. While the small sample size and retrospective character are limitations of our study, our preliminary results nonetheless challenge wide-spread preconceptions about the use of ketamine in schizophrenia patients and encourage further research into the option of using ketamine anaesthesia for ECT.

Venlafaxin-associated post-ictal asystole during electroconvulsive therapy.

While post-stimulus asystoles occur quite often during electroconvulsive therapy (ECT) post-ictal or post-seizure sinus bradycardias or even asystoles are rare events. We report the case of an 82-year-old female patient with a current major depressive episode, who developed the rare event of a post-ictal asystole of 6 s and 4 ventricular escape beats during ECT. In the past this patient with a bipolar disorder and mild Alzheimers disease had already been frequently treated with ECT with good success and no adverse events. Relevant comedication was venlafaxin, quetiapine, donepezil and clonidine, anesthesia was performed with ketamine and succinylcholine. Concurrent medication was completely unchanged compared to previous ECT sessions with the exception of venlafaxine, presumably at high serum levels. In summary, in line with some already existing reports, we expect the noradrenergic action of venlafaxin to have contributed substantially to the post-ictal asystole and want to indicate that the combination of ECT and venlafaxin might be harmful--especially in the elderly population.

Hypertonic-hyperoncotic solutions decrease cardiac troponin I concentrations in peripheral blood in a porcine ischemia-reperfusion model

In this study we addressed the question of whether the measurement of cardiac Troponin I (cTnI) is able to reflect beneficial effects of hypertonic-hyperoncotic solutions after transient cardiac arrest. Ten pigs were anaesthetized and cardiac arrest was induced by electric fibrillation. After 5 minutes of global ischemia, cardiac arrest was reversed by electric defibrillation. Upon return of spontaneous circulation 5 animals received hypertonic-hyperoncotic solutions (10% Hydroxyethylstarch 200/0.5 and 7.2% NaCl). The other animals received equivalent volumes of physiological saline. We observed that cTnI serum levels of animals treated with hypertonic-hyperoncotic solutions were significantly lower than those treated with saline. We conclude that hypertonic-hyperoncotic solutions may have cardioprotective effects.

Cardiac troponin I and cardiac troponin T increases in pigs during ischemia-reperfusion damage.

In this study we addressed the question of whether the measurement of cardiac Troponin T (cTnT) and cardiac Troponin I (cTnI) is able to detect myocardial cell damage in an ischemia-reperfusion model in pigs. To answer the question 3 pigs were anaesthesized and a cardiac arrest was induced by electric fibrillation. After 5 minutes of global ischemia the cardiac arrest was reversed by electric defibrillation until normal perfusion was restored. We could clearly demonstrate an increase of cTnT and cTnI 30 minutes after reperfusion indicating myocardial injury during ischemia and subsequent reperfusion. The cTnT as well as the cTnI serum levels increased till 180 minutes after reperfusion. This ischemia-reperfusion injury is likely induced by oxygen radicals generated during hypoxia and subsequent reperfusion We conclude from our first results that troponin measurements with commercial available test kits may also reflect myocardial cell damage in pigs as it was recently demonstrated in rats. Further studies are needed for correlation of troponin serum levels and histopathological damage in this model especially if it is used to test beneficial or toxicological effects of radical neutralizing drugs.

Electroconvulsive therapy selectively enhances amyloid β 1–42 in the cerebrospinal fluid of patients with major depression: A prospective pilot study

A complex interplay between β-amyloid (Aβ), Alzheimer׳s disease (AD) and major depression disorder (MDD) suggests that patients with MDD have an altered cerebral Aβ metabolism and an increased risk of developing AD. In order to elucidate the relationship between antidepressant treatment and Aβ metabolism in humans, we performed a study on Aβ peptides in the cerebrospinal fluid (CSF) in patients with MDD during electroconvulsive therapy (ECT) as an effective antidepressant treatment. We measured the levels of Aβ1-42, Aβ1-40 and of tau proteins in the CSF in 12 patients with MDD before and after a course of ECT. Aβ1-42 was significantly elevated after the ECT treatment compared to baseline, whereas no difference was found for other peptides and proteins such as Aβ1-40, Aβ ratio, total tau protein or its phosphorylated form. The most salient finding was, that the increase of Aβ1-42 after ECT was found in all patients with clinical response to the treatment, but not in those who did not respond. The number of ECT sessions of each responding patient correlated with the increase of Aβ1-42 in the CSF. Our data point towards to a specific antidepressant mechanism which is not based on a general increase of Aβ, but seems to involve merely Aβ1-42, the isoform with highest amyloidogenic potential. We present the first study in humans demonstrating an isolated mobilization of Aβ1-42 in the CSF of patients with depression who respond to an ECT treatment.

Management of severe postictal agitation after electroconvulsive therapy with bispectrum electroencephalogram index monitoring: a case report.

Abstract Postictal agitation (PIA) with possible severe implications occurs in approximately 10% of electroconvulsive therapy (ECT) sessions. The pathomechanism is not well understood, and suggested treatments are empirical based. We report a case of repetitive (47/57 sessions [83%]) severe PIA after ECT in a case with severe depression. If the minimal bispectrum EEG index (BIS) value, meaning the deepest level of sedation of the thiopental narcosis dropped below 50, PIA occurred in only 9.1%. Bispectral index (BIS) monitoring made prediction and prevention of PIA possible to some degree. Postictal agitation might occur in vulnerable patients when initial depth of anesthesia is too light.