Appropriate medication use in Dutch terminal care: study protocol of a multicentre stepped-wedge cluster randomized controlled trial (the AMUSE study).

BACKGROUND: Polypharmacy is common among patients with a limited life expectancy, even shortly before death. This is partly inevitable, because these patients often have multiple symptoms which need to be alleviated. However, the use of potentially inappropriate medications (PIMs) in these patients is also common. Although patients and relatives are often willing to deprescribe medication, physicians are sometimes reluctant due to the lack of evidence on appropriate medication management for patients in the last phase of life. The aim of the AMUSE study is to investigate whether the use of CDSS-OPTIMED, a software program that gives weekly personalized medication recommendations to attending physicians of patients with a limited life expectancy, improves patients' quality of life. METHODS: A multicentre stepped-wedge cluster randomized controlled trial will be conducted among patients with a life expectancy of three months or less. The stepped-wedge cluster design, where the clusters are the different study sites, involves sequential crossover of clusters from control to intervention until all clusters are exposed. In total, seven sites (4 hospitals, 2 general practices and 1 hospice from the Netherlands) will participate in this study. During the control period, patients will receive 'care as usual'. During the intervention period, CDSS-OPTIMED will be activated. CDSS-OPTIMED is a validated software program that analyses the use of medication based on a specific set of clinical rules for patients with a limited life expectancy. The software program will provide the attending physicians with weekly personalized medication recommendations. The primary outcome of this study is patients' quality of life two weeks after baseline assessment as measured by the EORTC QLQ-C15-PAL questionnaire, quality of life question. DISCUSSION: This will be the first study investigating the effect of weekly personalized medication recommendations to attending physicians on the quality of life of patients with a limited life expectancy. We hypothesize that the CDSS-OPTIMED intervention could lead to improved quality of life in patients with a life expectancy of three months or less. TRIAL REGISTRATION: This trial is registered at ClinicalTrials.gov (NCT05351281, Registration Date: April 11, 2022).

Medulloblastoma in adults: evaluation of the Dutch society for neuro-oncology treatment protocol.

PURPOSE: Medulloblastoma is a rare tumor in adults. The objective of this nationwide, multicenter study was to evaluate the toxicity and efficacy of the Dutch treatment protocol for adult medulloblastoma patients. METHODS: Adult medulloblastoma patients diagnosed between 2010 and 2018 were identified in the Dutch rare tumors registry or nationwide pathology database. Patients with intention to treat according to the national treatment protocol were included. Risk stratification was performed based on residual disease, histological subtype and extent of disease. All patients received postoperative radiotherapy [craniospinal axis 36 Gy/fossa posterior boost 19.8 Gy (14.4 Gy in case of metastases)]. High-risk patients received additional neoadjuvant (carboplatin-etoposide), concomitant (vincristine) and adjuvant chemotherapy (carboplatin-vincristine-cyclophosphamide) as far as feasible by toxicity. Methylation profiling, and additional next-generation sequencing in case of SHH-activated medulloblastomas, were performed. RESULTS: Forty-seven medulloblastoma patients were identified, of whom 32 were treated according to the protocol. Clinical information and tumor material was available for 28 and 20 patients, respectively. The histological variants were mainly classic (43%) and desmoplastic medulloblastoma (36%). Sixteen patients (57%) were considered standard-risk and 60% were SHH-activated medulloblastomas. Considerable treatment reductions and delays in treatment occurred due to especially hematological and neurotoxicity. Only one high-risk patient could complete all chemotherapy courses. 5-years progression-free survival (PFS) and overall survival (OS) for standard-risk patients appeared worse than for high-risk patients (PFS 69% vs. 90%, OS 81% vs. 90% respectively), although this wasn't statistically significant. CONCLUSION: Combined chemo-radiotherapy is a toxic regimen for adult medulloblastoma patients that may result in improved survival.

Effectiveness of the "Living with Cancer" peer self-management support program for persons with advanced cancer and their relatives: study protocol of a non-randomized stepped wedge study.

BACKGROUND: Persons with advanced cancer and their relatives experience physical, emotional, and psychosocial consequences of the illness. Most of the time, they must deal with these themselves. While peer self-management support programs may be helpful, there is little evidence on their value for this population. We present the research protocol of our SMART study that will evaluate the effectiveness of the "Living with Cancer" peer self-management support program, aimed at improving self-management behaviors, self-efficacy, and health-related quality of life of persons with advanced cancer and their relatives. METHODS: We will conduct a non-randomized stepped wedge study in the Netherlands. We will include 130 persons with advanced cancer and 32 relatives. Participants can choose to either start the program within 4 weeks after inclusion or after eight to 10 weeks. The "Living with Cancer" is a peer self-management support program, based on the Chronic Disease Self-Management Program. It consists of six 1,5 hours video-conferencing group meetings with eight to 12 participants, preceded by two or three preparatory audio clips with supportive text per session. The program has the following core components: the learning of self-management skills (action-planning, problem-solving, effective communication, and decision-making), discussing relevant themes (e.g. dealing with pain and fatigue, living with uncertainty, and future planning), and sharing experiences, knowledge, and best practices. The primary outcome for both persons with advanced cancer and relatives is self-management behavior assessed by the subscale "constructive attitudes and approaches" of the Health Education Impact Questionnaire. Secondary outcomes are other self-management behaviors, self-efficacy, health-related quality of life, symptoms, depression and anxiety, and loneliness. Participants complete an online questionnaire at baseline, and after eight and 16 weeks. After each session, they complete a logbook about their experiences. Group meetings will be video recorded. DISCUSSION: SMART aims to evaluate an innovative program building on an evidence-based self-management program. New features are its use for persons with advanced cancer, the inclusion of relatives, and the video-conferencing format for this population. The use of both quantitative and qualitative analyses will provide valuable insight into the effectiveness and value of this program. TRIAL REGISTRATION: This study was registered in the Dutch Trial Register on October 2021, identifier NL9806 .

The views of healthcare professionals on self-management of patients with advanced cancer: An interview study.

OBJECTIVES: Self-management of patients with advanced cancer is challenging. Although healthcare professionals may play a crucial role in supporting these patients, scant scientific attention has been paid to their perspectives. Therefore, we examined healthcare professionals' views on self-management and self-management support in this population. METHODS: We conducted qualitative interviews with 27 purposively sampled medical specialists (n = 6), nurse specialists (n = 6), general practitioners (n = 8) and homecare/ hospice nurses (n = 7) in the Netherlands. Transcripts were analysed using thematic analysis. RESULTS: Healthcare professionals experienced self-management of patients with advanced cancer to be diverse, dynamic and challenging. They adopted instructive, collaborative and advisory roles in self-management support for this population. Whereas some professionals preferred or inclined towards one role, others indicated to switch roles, depending on the situation. CONCLUSIONS: Just like patients with advanced cancer, healthcare professionals differ in their views and approaches regarding self-management and self-management support in this population. Therefore, instructive, collaborative and advisory self-management support roles will all be useful under certain circumstances. PRACTICE IMPLICATIONS: Healthcare professionals can support self-management by being aware of their own views and communicating these clearly to their patients and colleagues. Education in self-management support should include self-reflection skills and discuss the relation between self-management and professional care.

Feasibility and validity of a tool for identification of people with intellectual disabilities in need of palliative care (PALLI).

BACKGROUND: There is a need for a specific tool that supports healthcare professionals in timely identifying people with intellectual disabilities (ID) in need of palliative care. Therefore, we developed PALLI: a tool for screening deteriorating health, indicative of a limited life expectancy. AIMS: We evaluated feasibility, construct validity and predictive validity of PALLI. METHODS: 190 people with ID likely to be in need of palliative care were included. Physicians and daily care professionals (DCPs) completed PALLI and provided information on health outcomes at baseline, after 5-6 months and after 10-12 months. Linear Mixed Models and Generalized Linear Mixed Models were used to test validity. RESULTS: Feasibility was adequate: physicians and DCPs were able to answer most items with 'yes' or 'no' and within a short amount of time. Construct validity was promising: a higher PALLI score at baseline was related to a higher level of decline in health, a higher symptom burden, a lower quality of life and more ADL-dependency at baseline. Predictive validity: only a higher physician-reported PALLI score at baseline significantly increased risk of death within 12 months. CONCLUSIONS: PALLI shows promising feasibility and validity and has potential as a tool for timely identifying people with ID who may benefit from palliative care.

To be in pain (or not): a computer enables outpatients to inform their physician.

BACKGROUND: In the outpatient oncology clinic, pain management is often inadequate. Incorporating a systematic pain management program into visits is likely to improve this. We implemented an integrated program, including a structured pain assessment, pain treatment protocol and patient education module. In the present study, we investigated whether this intervention improved pain control. PATIENTS AND METHODS: At seven oncology outpatient clinics, patients were asked to register their pain intensity on a touch screen computer. These scores were made available into their electronic medical records. Additionally, a hospital-wide treatment protocol for cancer-related pain and a patient education module were developed. A data warehouse system enabled us to extract patient data from the electronic medical record anonymously and to use them for analysis. The primary outcome of the study was the percentage of patients with moderate to severe pain [current pain (CPI), NRS > 4] measured during 2 weeks at the start and 6 months after implementation. As secondary outcomes, we studied the percentage of pain registrations in specific patient groups and the percentage of patients treated with a curative and a palliative intention with (moderate-severe) pain. Differences were tested with the χ(2) test. RESULTS: During the first 6 months, 3407 of the 4345 patients (78%) registered their pain intensity on the touch screen computer. The percentage of patients with moderate to severe CPI decreased 32% (P = 0.021): from 12.5% at start to 8.5% after 6 months. More patients in the palliative phase than in the curative phase of their disease registered their pain intensity (82% versus 75%, respectively, P < 0.005), and more patients in the palliative phase experienced moderate to severe pain (23% versus 14%, respectively, P < 0.001). CONCLUSION: Pain registration by patients themselves is feasible, provides insight into patients' pain intensity and may improve pain control in outpatients with cancer-related pain. CLINICAL TRIAL NUMBER: Because this is an innovation project and not a primary research project, it has no clinical trial number. The protocol and all materials involved were approved by the Institutional Review Board of the Erasmus MC (MEC-2009-324).

Elucidating the behavior of physical fatigue and mental fatigue in cancer patients: a review of the literature.

BACKGROUND: Although the multidimensional nature of cancer-related fatigue is widely accepted, it could be questioned whether fatigue dimensions are expressions of one symptom (multidimensional concept) or expressions of several phenomena that are all called fatigue but actually are separate symptoms (multiple-symptom concept). METHODS: Therefore, we investigated in this review whether physical fatigue and mental fatigue behave differently in cancer patients by studying their intensity in different stages of cancer, their changes in intensity during anti-tumor therapy, the variables to which they are related, and their changes in intensity by interventions on fatigue. RESULTS: In some studies, physical fatigue and mental fatigue behaved similarly: they were both more intense in cancer patients than in healthy controls, and sometimes, they had the same course during anti-tumor therapy, or both improved during an intervention. On the contrary, there were some studies suggesting that physical fatigue and mental fatigue behaved differently: physical fatigue seemed to be more prominent than mental fatigue in some stages of the disease trajectory; several studies reported changes in physical fatigue not accompanied by changes in mental fatigue during anti-tumor therapy or by interventions aimed to relieve fatigue; and physical fatigue and mental fatigue had different correlates. CONCLUSIONS: In conclusion, we found some studies in which physical fatigue and mental fatigue behaved differently. These findings might indicate that physical fatigue and mental fatigue are separate phenomena. To prove this multiple-symptom concept, studies on the pathophysiological mechanisms leading either to physical fatigue or to mental fatigue are urgently needed.

Higher doses of opioids in patients who need palliative sedation prior to death: cause or consequence?

BACKGROUND: Palliative sedation (PS) is necessary in a significant percentage of patients dying on an acute palliative care unit (PCU). Common indications are terminal restlessness, pain and dyspnoea. On our PCU, terminal restlessness was the main indication for PS but pain was the most prevalent symptom during admission. Because delirium is often drug induced in terminal cancer patients and opioids are amongst the most frequently implicated drugs, we hypothesised that the underlying pain problem and its treatment might have been related to the need for sedation. PATIENTS AND METHODS: To test this hypothesis, we did a retrospective analysis on the use of medication with potential cognitive side-effects, focusing on analgesics, in 68 patients who died on the PCU after PS and 89 patients who died without PS. RESULTS: Ultimately sedated patients used opioids in significantly higher doses; they were more often treated with a rotation to another opioid and with amitriptyline. The dose of opioids used at various time points between admission and death was strongly related to the probability of PS. CONCLUSIONS: Our findings support the hypothesis that, although pain was not the main indication for PS, pain and its treatment might have been primarily related to the need for palliative sedation in this patient cohort.

The Distress Thermometer assessed in women at risk of developing hereditary breast cancer.

OBJECTIVES: The Distress Thermometer (DT) is a promising instrument to get insight into distress experienced by cancer patients. At our Family Cancer Clinic the DT, including an adapted problem list, was completed by 100 women at increased risk of developing hereditary breast cancer (mean age 45.2 years; SD: 10.5). Additionally, the women filled in either the Hospital Anxiety and Depression Scale as psychological component (n=48) or the somatic subscale of the Symptom Checklist-90 as somatic component (n=50) to identify associations with the DT-score. Further, the women filled in an evaluation form. RESULTS: The median score on the DT was 2 (range: 0-9). With regression analysis adjusted for age, the contribution of mood and somatic complaints, respectively, was investigated. The standardized regression coefficient for anxiety was 0.32 (ns), for depression 0.14 (ns) and for the somatic subscale 0.49 (p<0.001). The explained variance for anxiety and depression was 16%, and for somatic complaints 24%. The differences between the coefficients were not significant. Evaluation forms were returned by 73 women. In 50% of the cases, the physician had discussed the DT/problem list, which was appreciated by the majority of these women (80%). Sixty-two percent of the women would recommend the use of the DT for other patients. CONCLUSION: The use of the DT/problem list seems promising for the current population, and was appreciated by the majority of the women. As mood and somatic complaints did not differ significantly in explaining the experienced distress, other candidate factors need to be examined.

The pathogenesis of cancer related fatigue: could increased activity of pro-inflammatory cytokines be the common denominator?

Cancer related fatigue (CRF), defined as a persistent subjective sense of tiredness related to cancer or cancer treatment that interferes with daily functioning, is highly prevalent and probably the most underestimated and insufficiently treated complication in cancer patients. Therefore, unravelling the pathogenesis of CRF is of great importance allowing the identification of novel therapeutic targets. It is generally believed that the pathogenesis is multicausal, explaining why most therapeutic interventions directed towards only one potential causative factor are unsuccessful. In this regard, it is of interest that increased activity of pro-inflammatory cytokines might be a common denominator causing CRF. Detailed insight in the central role of increased activity of pro-inflammatory cytokines in CRF will hopefully offer an effective approach in the treatment of CRF by affecting a broad array of proposed causative factors such as anaemia, disturbances of the hypothalamic-pituitary-adrenal axis and altered brain serotonin metabolism.

Function of local networks in palliative care: a Dutch view.

BACKGROUND: Although network formation is considered an effective method of stimulating the integrated delivery of palliative care, scientific evidence on the usefulness of network formation is scarce. In 1998 the Ministry of Health of The Netherlands started a 5-year stimulation program on palliative care by founding and funding six regional Centres for the Development of Palliative Care. These centers were structured around pivotal organizations such as university hospitals and comprehensive cancer centers. As part of the stimulation program a locoregional network model was introduced within each center for the Development of Palliative Care to integrate palliative care services in the Dutch health care system. OBJECTIVE: We performed a study on network formation in the southwestern area of The Netherlands with 2.4 million inhabitants. The study aimed to answer the following questions: (1) how do networks in palliative care develop, which care providers participate and how do they function? (2) which are the achievements of the palliative care networks as perceived by their participants? (3) which are the success factors of the palliative care networks according to their participants and which factors predict the achievements? DESIGN: Between September 2000 and January 2004 eight local palliative care networks in the region of the Center for Development of Palliative Care-Rotterdam (southwestern area of The Netherlands) were closely followed to gain information on their characteristics and developmental course. MEASUREMENTS: At the start of the study semistructured interviews were held with the coordinators of the eight networks. The information from these interviews and from the network documents were used to constitute a questionnaire to assess the opinions and experiences of the network participants. RESULTS: According to the vast majority of responders, the most important reason to install the networks was the lack of integration between the existing local health care services. The networks were initiated to stimulate mutual collaboration, improve accessibility to health care services and increase the quality of these services. The most important achievements obtained by the palliative care networks were: increase in personal contacts between colleagues in a region, improved engagement and collaboration between participating organizations, enhanced insight in the health care provisions, joined initiatives for the development of new care products, and organization of patient-tailored care. Important success factors for the networks were deemed: fruitful mutual contacts, regular funding and the collective development of care products. By logistic regression analyses, the collective development of new care products and the organization of case discussions between caregivers from different health care services turned out to be the most important predictors for success of the palliative care networks. CONCLUSIONS: Projects that stimulate the communication between professionals appear to improve the mutual collaboration between individual participants and between the participating organizations, which consequently enhances the quality of palliative care.

Phase II study of first-line chemotherapy with temozolomide in recurrent oligodendroglial tumors: the European Organization for Research and Treatment of Cancer Brain Tumor Group Study 26971.

PURPOSE: Oligodendroglial tumors are chemotherapy-sensitive tumors, with two thirds of patients responding to combination chemotherapy with procarbazine, lomustine, and vincristine (PCV). Temozolomide (TMZ), a new alkylating and methylating agent, has demonstrated high response rates in patients with recurrent anaplastic astrocytoma. We investigated TMZ as first-line chemotherapy in recurrent oligodendroglial tumors (OD) and mixed oligoastrocytomas (OA) after surgery and radiation therapy. PATIENTS AND METHODS: In a prospective, nonrandomized, multicenter, phase II trial, patients were treated with 200 mg/m2 of TMZ on days 1 through 5 in 28-day cycles for 12 cycles. Patients with a recurrence after prior surgery and radiotherapy, and with measurable and enhancing disease on magnetic resonance imaging (MRI) were eligible for this study. Patients with large lesions and mass effect or with new clinical deficits were not eligible. Pathology and the MRI scans of all responding patients were centrally reviewed. RESULTS: Thirty-eight eligible patients were included. In three patients, pathology review did not confirm the presence of an OD or OA. TMZ was generally well tolerated. The most frequent side effects were hematologic; only one patient discontinued treatment for toxicity. In 20 (52.6%) of 38 patients (95% exact confidence interval, 35.8% to 69.0%), a complete (n = 10) or partial response to TMZ was observed. The median time to progression was 10.4 months for all patients and 13.2 months for responding patients. At 12 months from the start of treatment, 40% of patients were still free from progression. CONCLUSION: TMZ provides an excellent response rate with good tolerability in chemotherapy-naive patients with recurrent OD. A randomized phase III study comparing PCV with TMZ is warranted.

Second-line chemotherapy with temozolomide in recurrent oligodendroglioma after PCV (procarbazine, lomustine and vincristine) chemotherapy: EORTC Brain Tumor Group phase II study 26972.

BACKGROUND: Oligodendroglial tumors are chemosensitive, with two-thirds of patients responding to PCV combination chemotherapy with procarbazine, lomustine (CCNU) and vincristine. Temozolomide (TMZ), a new alkylating and methylating agent has shown high response rates in recurrent anaplastic astrocytoma. We investigated this drug in recurrent oligodendroglial tumors (OD) and mixed oligoastrocytomas (OA) after prior PCV chemotherapy and radiation therapy. PATIENTS AND METHODS: In a prospective non-randomized multicenter phase II trial patients were treated with TMZ 150 mg/m(2) on days 1-5 in cycles of 28 days for 12 cycles. Eligible patients had a recurrence after prior PCV chemotherapy, with measurable and enhancing disease as shown by magnetic resonance imaging. Pathology and all responses were centrally reviewed. RESULTS: Thirty-two eligible patients were included. In four patients the pathology review did not confirm the presence of an OD or OA. Twelve of 24 patients [50%, 95% confidence interval (CI) 29% to 71%] evaluable for response to first-line PCV chemotherapy had responded to PCV. Temozolomide was in general well tolerated; the most frequent side-effects were hematological. One patient discontinued treatment due to toxicity. In seven of 28 patients (25%, 95% CI 11% to 45%) with histologically confirmed OD an objective response to TMZ was observed. Median time to progression for responding patients was 8.0 months. After 6 and 12 months from the start of treatment, 29% and 11% of patients, respectively, were still free from progression. CONCLUSIONS: TMZ may be regarded as the preferred second-line treatment in OD after failure of PCV chemotherapy. Further studies on TMZ in OD are indicated.

Problem solving by telephone in palliative care: use of a predetermined assessment tool within a program of home care technology.

In the Rotterdam Cancer Institute, nurses from the palliative care unit take care of accessibility outside office hours for patients transferred home with technical equipment for symptoms control. The nurses use a predetermined assessment tool (PAT) for handling telephone calls. A retrospective evaluation on the registration forms used over the years 1997-1999 was performed to evaluate the telephone service. A total of 124 patients in need of technical support was transferred from the hospital during the study period: 52 in 1997, 33 in 1998, and 39 in 1999. Over the years, 157 calls were registered from 64 (52%) patients. In 1997, the majority of the calls (73%) came from the patient or the family. The frequency of calls from the general practitioner did not change, but calls from the district nurse increased from 12% in 1997 to 35% in 1998, and 48% in 1999. Professionals working in nursing homes have used the telephone service since 1998. The reasons for calling were pain (40%), symptoms other than pain (19%), technical problems (33%), general information and advice (6%), and logistic problems (2%). In 152 of the 157 telephone calls (97%), problems could be solved without admission. The mean time to answer a call was 16 minutes. The telephone service and the use of the PAT made it possible to solve 97% of problems without admission.

[Treatment of pain in cancer with systemically administered opioids]. / Behandeling van pijn bij kanker met systemisch toegediende opioïden.

The World Health Organization guidelines for cancer pain relief have been proven efficacious in 90% of the patients with cancer pain. The patient's self-report of pain is the focus of treatment. When initiating treatment, controlled-release preparations of opioids are generally favoured, and are combined with immediate release morphine to prevent or treat 'breakthrough' pain and to enable the optimum opioid dosage to be calculated. (Breakthrough pain is a transient increase in pain in a patient who has stable, persistent pain treated with opioids.) In patients with an unfavourable balance between analgesia and side effects, the following strategies may be useful, together with appropriate treatment of the side effects: Sequential opioid trials (so-called opioid rotation) is an approach which is effective in 50-70% of the patients. Changing the route of opioid administration is successful in 70-95% of the patients. When selecting an invasive technique, continuous subcutaneous infusion is medically preferred. Spinal analgesia is an alternative. Knowledge of the relative potency of opioid drugs and of their biologic availability is needed to guide changes in drugs or routes of administration.

Flumazenil therapy for hepatic encephalopathy. A double-blind cross over study.

OBJECTIVES AND METHODS: Thirty-one patients with acute or chronic liver disease were included in the study to investigate the effect of flumazenil on hepatic encephalopathy. After screening for recent benzodiazepine use or non-hepatic causes of encephalopathy, 18 patients entered a double-blind cross-over study. The 13 remaining patients, most of them with renal failure or recent use of benzodiazepines, were given flumazenil in an open study. In the controlled study, flumazenil (1.0 mg) or placebo was given in a single injection on two separate days to study the immediate effect; half the patients received a continuous infusion of flumazenil (0.25 mg/h) or placebo for two 3-day periods to study a potential steady state effect. In the open study, a single bolus of flumazenil (1.0 mg) was given. RESULTS: In the controlled study, fifteen minutes after bolus injection, the clinical grade of hepatic encephalopathy decreased in 6 patients after injection of flumazenil, whereas a decrease was found in 2 after the placebo (P = 0.06). However, the EEG grade did not change in any of the patients, and the changes in the mean dominant frequency as measured by spectral analysis did not differ between flumazenil and the placebo. Furthermore, patients on flumazenil did not differ significantly from those on placebo during the infusion period. Subgroup analysis of underlying liver disease and the causes of encephalopathy revealed a trend for clinical improvement only in the patients with chronic liver disease, but without significant changes in the mean dominant frequency. In the open study, the clinical grade of encephalopathy decreased in 3 patients and, in contrast to the controlled study, the EEG also improved in 2 patients and the mean dominant frequency increased significantly. Responders had previously used benzodiazepines. CONCLUSION: Our study does not support a major therapeutic effect of flumazenil on hepatic encephalopathy.

Extracellular brain glutamate during acute liver failure and during acute hyperammonemia simulating acute liver failure: an experimental study based on in vivo brain dialysis.

Hyperammonemia is thought to be important in the pathogenesis of hepatic encephalopathy. However, the mechanism leading to ammonia toxicity is still not known. Since the metabolism of the most important excitatory neurotransmitter, glutamate, is closely linked to that of ammonia, it has been postulated that hyperammonemia lowers the availability of the neurotransmitter glutamate. To study this hypothesis, we used brain dialysis to measure glutamate levels in extracellular cerebral fluid from rabbits with acute ischemic liver failure or acute hyperammonemia. The basal glutamate concentration was found to be increased during both acute liver failure (start of experiments 4.9 +/- 1.7 mumol/l; end of experiments 9.5 +/- 2.1 mumol/l, n = 6, difference p < 0.05) and acute hyperammonemia (start of experiments 4.4 +/- 1.2 mumol/l; end of experiments 7.3 +/- 1.8 mumol/l, n = 7, difference p > 0.05) (mean +/- SEM). Both the veratridine- and the potassium-evoked glutamate release were increased during acute liver failure but appeared normal during hyperammonemia. We conclude that during acute liver failure and acute hyperammonemia in the rabbit there is no decreased glutamate availability in the extracellular space of the cortical brain; on the contrary, we found evidence for increased extracellular glutamate concentrations in the cortical brain, which were more pronounced in acute liver failure. Experimental hepatic encephalopathy is thus not due to cerebral glutamate deficiency.