Modification in ICU Design May Affect Delirium and Circadian Melatonin: A Proof of Concept Pilot Study.

OBJECTIVES: Nonpharmacologic delirium management is recommended by current guidelines, but studies on the impact of ICU design are still limited. The study's primary purpose was to determine if a multicomponent change in room design prevents ICU delirium. Second, the influence of lighting conditions on serum melatonin was assessed. DESIGN: Prospective observational cohort pilot study. SETTING: The new design concept was established in two two-bed ICU rooms of a university hospital. Besides modifications aimed at stress relief, it includes a new dynamic lighting system. PATIENTS: Seventy-four adult critically ill patients on mechanical ventilation with an expected ICU length of stay of at least 48 hours, treated in modified or standard rooms. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The clinical examination included a prospective assessment for depth of sedation, delirium, and pain every 8 hours using validated scores. Blood samples for serum melatonin profiles were collected every 4 hours for a maximum of three 24-hour periods. Seventy-four patients were included in the analysis. Seventy-six percent ( n = 28) of patients in the standard rooms developed delirium compared with 46% of patients ( n = 17) in the modified rooms ( p = 0.017). Patients in standard rooms (vs. modified rooms) had a 2.3-fold higher delirium severity (odds ratio = 2.292; 95% CI, 1.582-3.321; p < 0.0001). Light intensity, calculated using the measure of circadian effective irradiance, significantly influenced the course of serum melatonin ( p < 0.0001). Significant interactions ( p < 0.001) revealed that differences in serum melatonin between patients in standard and modified rooms were not the same over time but varied in specific periods of time. CONCLUSIONS: Modifications in ICU room design may influence the incidence and severity of delirium. Dedicated light therapy could potentially influence delirium outcomes by modulating circadian melatonin levels.

Concepts for exercise therapy in prehabilitation for elderly people with frailty or pre-frailty prior to elective surgery. A scoping review.

BACKGROUND: Frailty is a state of reduced functional capacities in older people that can be reversed through multimodal therapy concepts. The effect of preoperative prehabilitation on frailty has been examined, but the heterogeneity of exercise regimens has prevented conclusive evidence. This scoping review analyses prehabilitation interventions, particularly exercise methods, published in trials for prefrail and frail elderly patients. METHOD: We identified studies evaluating prehabilitation for frail elderly using the framework of Arksey and O'Malley. Five scientific databases were searched until March 2022. Articles were screened by two independent reviewers. Data extraction included, but was not limited to, study design, intervention protocol of the prehabilitation including exercise therapy and additional interventions, and safety of the reported exercise concepts. RESULTS: Nineteen studies were included, offering an insight into the utilized prehabilitation concepts for exercise. All study interventions were based around exercise programs, potentially with complementary interventions. Twelve studies based their exercise programs on a combination of endurance and strength training. Breathing exercises were prescribed in five studies, flexibility routines in five, and one study included balance training. Further interventions included nutritional counselling/supplementation in nine studies, smoking/alcohol cessation in five, in addition to two physiological and three medical/pharmaceutical interventions. DISCUSSION: Prehabilitation for the frail elderly is safe and feasible. The general concept of prehabiliation for frail patients is promising. An exercise program should focus on improving the patient's endurance and strength, considering the positive effects that can be provided by breathing exercises and other additional interventions, such as nutritional support or lifestyle counselling.

Intravenous vitamin C therapy in adult patients with sepsis: A rapid practice guideline.

BACKGROUND: This Rapid Practice Guideline provides an evidence-based recommendation to address the question: in adults with sepsis or septic shock, should we recommend using or not using intravenous vitamin C therapy? METHODS: The panel included 21 experts from 16 countries and used a strict policy for potential financial and intellectual conflicts of interest. Methodological support was provided by the Guidelines in Intensive Care, Development, and Evaluation (GUIDE) group. Based on an updated systematic review, and the grading of recommendations, assessment, development, and evaluation approach, we evaluated the certainty of evidence and developed recommendations using the evidence-to-decision framework. We conducted an electronic vote, requiring >80% agreement among the panel for a recommendation to be adopted. RESULTS: At longest follow-up, 90 days, intravenous vitamin C probably does not substantially impact (relative risk 1.05, 95% confidence interval [CI] 0.94 to 1.17; absolute risk difference 1.8%, 95% CI -2.2 to 6.2; 6 trials, n = 2148, moderate certainty). Effects of vitamin C on mortality at earlier timepoints was of low or very low certainty due to risk of bias of the included studies and significant heterogeneity between study results. Few adverse events were reported with the use of vitamin C. The panel did not identify any major differences in other outcomes, including duration of mechanical ventilation, ventilator free days, hospital or intensive care unit length of stay, acute kidney injury, need for renal replacement therapy. Vitamin C may result in a slight reduction in duration of vasopressor support (MD -18.9 h, 95% CI -26.5 to -11.4; 21 trials, n = 2661, low certainty); but may not reduce sequential organ failure assessment scores (MD -0.69, 95% CI -1.55 to 0.71; 24 trials, n = 4002, low certainty). The panel judged the undesirable consequences of using IV vitamin C to probably outweigh the desirable consequences, and therefore issued a conditional recommendation against using IV vitamin C therapy in sepsis. CONCLUSIONS: The panel suggests against use of intravenous vitamin C in adult patients with sepsis, beyond that of standard nutritional supplementation. Small and single center trials on this topic should be discouraged.

Circadian rhythm disruption in critically ill patients.

Patients admitted to the intensive care unit (ICU) are in need of continuous organ replacement strategies and specialized care, for example because of neurological dysfunction, cardio-pulmonary instability, liver or kidney failure, trauma, hemorrhagic or septic shock or even preterm birth. The 24-h nursing and care interventions provided to critically ill patients significantly limit resting and/or recovery phases. Consecutively, the patient's endogenous circadian rhythms are misaligned and disrupted, which in turn may interfere with their critical condition. A more thorough understanding of the complex interactions of circadian effectors and tissue-specific molecular clocks could therefore serve as potential means for enhancing personalized treatment in critically ill patients, conceivably restoring their circadian network and thus accelerating their physical and neurocognitive recovery. This review addresses the overarching issue of how circadian rhythms are affected and disturbed in critically ill newborns and adults in the ICU, and whether the conflicting external or environmental cues in the ICU environment further promote disruption and thus severity of illness. We direct special attention to the influence of cell-type specific molecular clocks on with severity of organ dysfunctions such as severity of brain dysfunction, pneumonia- or ventilator-associated lung inflammation, cardiovascular instability, liver and kidney failure, trauma, and septic shock. Finally, we address the potential of circadian rhythm stabilization to enhance and accelerate clinical recovery.

Presurgical diffusion metrics of the thalamus and thalamic nuclei in postoperative delirium: A prospective two-centre cohort study in older patients.

BACKGROUND: The thalamus seems to be important in the development of postoperative delirium (POD) as previously revealed by volumetric and diffusion magnetic resonance imaging. In this observational cohort study, we aimed to further investigate the impact of the microstructural integrity of the thalamus and thalamic nuclei on the incidence of POD by applying diffusion kurtosis imaging (DKI). METHODS: Older patients without dementia (≥65 years) who were scheduled for major elective surgery received preoperative DKI at two study centres. The DKI metrics fractional anisotropy (FA), mean diffusivity (MD), mean kurtosis (MK) and free water (FW) were calculated for the thalamus and - as secondary outcome - for eight predefined thalamic nuclei and regions. Low FA and MK and, conversely, high MD and FW, indicate aspects of microstructural abnormality. To assess patients' POD status, the Nursing Delirium Screening Scale (Nu-DESC), Richmond Agitation Sedation Scale (RASS), Confusion Assessment Method (CAM) and Confusion Assessment Method for the Intensive Care Unit score (CAM-ICU) and chart review were applied twice a day after surgery for the duration of seven days or until discharge. For each metric and each nucleus, logistic regression was performed to assess the risk of POD. RESULTS: This analysis included the diffusion scans of 325 patients, of whom 53 (16.3 %) developed POD. Independently of age, sex and study centre, thalamic MD was statistically significantly associated with POD [OR 1.65 per SD increment (95 %CI 1.17 - 2.34) p = 0.004]. FA (p = 0.84), MK (p = 0.41) and FW (p = 0.06) were not significantly associated with POD in the examined sample. Exploration of thalamic nuclei also indicated that only the MD in certain areas of the thalamus was associated with POD. MD was increased in bilateral hemispheres, pulvinar nuclei, mediodorsal nuclei and the left anterior nucleus. CONCLUSIONS: Microstructural abnormalities of the thalamus and thalamic nuclei, as reflected by increased MD, appear to predispose to POD. These findings affirm the thalamus as a region of interest in POD research.

Presurgical Thalamus Volume in Postoperative Delirium: A Longitudinal Observational Cohort Study in Older Patients.

BACKGROUND: Previous studies suggest a role of the thalamus in cognitive function, while others implicate it as a central effect site of anesthetics. Yet, its role in postoperative neurocognition in the aging brain remains uncertain. We used presurgical thalamic volume as a functional indicator and determined its association with postoperative delirium (POD). METHODS: For this study, 301 older adults (aged ≥65) without dementia and scheduled for surgery were enrolled. Before surgery, participants underwent magnetic resonance imaging (MRI). Thalamus volume was segmented using Freesurfer (Version 5.3.). Participants were screened for POD twice a day until discharge or for a maximum of 7 days. POD was defined as a positive screening on ≥1 of 4 validated instruments: Richmond Agitation Sedation Scale (RASS), Nursing Delirium Screening Scale (Nu-DESC), Confusion Assessment Method (CAM), and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) score. A logistic regression associated thalamus volume with POD with adjustment for age, global brain atrophy, and physical status according to the American Society of Anesthesiologists (ASA) classification. RESULTS: In this cohort, 44 participants (14.6%) were diagnosed with POD. Independently of age, global brain atrophy, and physical status score, a higher preoperative thalamus volume was associated with a reduced odds of POD (odds ratio per 1-cm3 increment; 0.73 [95% confidence interval (CI), 0.58-0.92]; P = .008). CONCLUSIONS: A larger thalamus volume was associated with reduced odds of POD. Thus, the thalamus marks a region of interest in POD in the aging brain. These findings may help to understand the neuronal basis of POD.

[Light Therapy for Prevention of Delirium in Critically Ill Patients: What's the Evidence?] / Lichttherapie zur Delirprävention bei Intensivpatienten: Was sagt die Evidenz?

Circadian dysrhythmia affects the majority of ICU patients and has far-reaching effects on organ functioning. At the level of the central nervous system, circadian misalignment facilitates executive cognitive dysfunction and the development of ICU delirium. The pathophysiological mechanisms, especially in the cohort of critically ill patients, appear to be complex, multilayered and far from understood. Results from preliminary research indicate that multidimensional, patient-specific chronotherapeutic concepts developed specifically for the ICU setting may help improve the healing process of patients. Circadian lighting therapy might be a promising intervention in this context.

The role of simulated-experience and descriptive formats on perceiving risks of strong opioids: A randomized controlled trial with chronic noncancer pain patients.

OBJECTIVES: Opioid prescription rates worldwide suggest miscalibrated risk perceptions among those who prescribe, dispense, and take opioids. Findings from cognitive science show that risk perceptions can differ systematically depending on whether people learn about risks by description or experience. We investigated the effects of descriptive and simulated experience risk formats on patients' risk perceptions and behavior regarding long-term strong opioid use. METHODS: 300 German patients with chronic noncancer pain were randomly assigned in an exploratory randomized controlled trial to either a descriptive format (fact box) or a simulated experience format (interactive simulation). Primary endpoints were subjective and objective risk perceptions and intended intake behavior. RESULTS: Both formats significantly improved patients' objective risk perception; patients who saw the fact box estimated some outcomes more accurately (p = .031). Formats were equally effective in improving patients' subjective risk perception in terms of opioids' harms; however, patients receiving the simulation showed a greater reduction and termination of their opioid intake (p = .030) and a higher uptake of alternative therapies. CONCLUSIONS: Descriptive and simulated experience risk formats improve risk perceptions and behavior regarding potent but highly risky drugs. PRACTICE IMPLICATIONS: To eliminate risky behavior, simulated experience formats may be superior to descriptive formats.

Perioperative Management of Alcohol Withdrawal Syndrome.

BACKGROUND: In the perioperative course, alcohol withdrawal syndrome (AWS) can occur in any setting, especially in aero-digestive and acute trauma surgery. Challenging issues are the overlap of other forms of delirium in perioperative and intensive care settings as well as general anesthesia masking the onset of withdrawal symptoms. In contrast to other etiologies of delirium, the pathophysiology and thus treatment strategy of AWS is different: the key point is the tolerance to GABAergic molecules of alcohol-dependent subjects resulting in central nervous hyperactivity once the effect of alcohol or other GABA-stimulating agents is decreased. SUMMARY: Despite limitations due to insufficient accuracy of self-reporting questionnaires and limited feasibility in emergency settings, the AUDIT and the shortened AUDIT-C are the standard tools for detection of alcohol use disorders (AUD), as well as predicting AWS risk and severity in approximately half of these AUD patients. The most important risk factors for AWS are a high blood alcohol concentration at hospital admission, AWS episodes in medical history, and lack of control of alcohol use. Patients considered at risk for severe AWS must be treated with prophylactic medication before the onset of symptoms. Thiamine supplementation is required for all malnourished alcohol-dependent patients. Writing down alcohol-related diagnoses in the medical records requires the patient's presumed consent after shared decision-making. These reports should remain strictly confidential if the patient desires. Psychological support for the perioperative period as well as the following course should be offered to all AUD patients including support in short- and long-term detoxification. Alternative diagnoses must be ruled out with no timely delay, especially if fever and coma are the leading symptoms. The backbone of AWS therapy is the symptom-triggered administration of intravenous benzodiazepines (BZO) in escalating doses until the aimed revised Clinical Institute Withdrawal Assessment for Alcohol Scale (CIWA-Ar) or Richmond Agitation-Sedation Scale (RASS) score is achieved. Clonidine, dexmedetomidine, baclofen, ketamine, and neuroleptics may be used as symptom-orientated adjuncts. The therapeutic administration of ethanol or clomethiazole is considered to be harmful in critically ill patients after the onset of AWS. General supportive and intensive care including high-dose thiamine supplementation are mandatory in severe AWS cases. The timely differential diagnosis of delirium is important - and AWS is a diagnosis of exclusion - because BZO are strongly recommended for AWS patients but may not be the treatment of choice in other etiologies of delirium. KEY MESSAGES: Screening for AWS risk factors should be integrated in the preoperative and emergency assessment. Other severe diagnoses must be ruled out before the diagnosis of AWS can be established. Preventive treatment should be given to high-risk patients scoring positive for AUD and for patients with a lack of alcohol use control. The principles of AWS therapy are symptom-orientated doses of BZO and as adjuncts α2-agonists, neuroleptics, and others guided by repeated reassessment with validated tools and thiamine administration. Length of stay and morbidity are reduced if AWS therapy is symptom-orientated and protocol-based.

[Perioperative Neurocognitive Disorders - Postoperative Prevention Strategies]. / Wie können postoperativ ein Delir und eine neurokognitive Störung verhindert werden?

Postoperative delirium (POD) is a common and serious complication after surgery. It is associated with increased morbidity and mortality as well as neurocognitive disorder and associated loss of autonomy and increased need for care. As professionals, it is our duty to treat our patients in a holistic individual concept with the aim to reintegrate our patients into their home and social environment afterwards. In addition to preoperative and intraoperative interventions, postoperative prevention is of particular importance. This article focuses on non-pharmacological prevention strategies to avoid postoperative delirium and neurocognitive disorder in postoperative inpatient care. It is based on the "Evidence-based and consensus-based guideline on postoperative delirium". Thus, risk factors are addressed and non-pharmacological strategies are presented, which include reorientation, mobilization and nutritional support. Interprofessional cooperation plays just as important a role as the implementation of the listed preventive measures. Finally, the modified Hospital Elder Life Program is presented, which presents and applies preventive measures as a system-oriented and interdisciplinary concept, which "prevents functional decline and allows older adults to return home at the maximal level of independence". From our point of view, the training of a professional delirium team is a future-oriented complementary measure in the treatment concept of Perioperative Neurocognitive Disorders (PND), which finds its justification as an interface in the treatment of high-risk patients.

Association between potassium concentrations, variability and supplementation, and in-hospital mortality in ICU patients: a retrospective analysis.

BACKGROUND: Serum potassium concentrations are commonly between 3.5 and 5.0 mmol/l. Standardised protocols for potassium range and supplementation in the ICU are lacking. The purpose of this retrospective analysis of ICU patients was to investigate potassium concentrations, variability and supplementation, and their association with in-hospital mortality. METHODS: ICU patients ≥ 18 years, with ≥ 2 serum potassium values, treated at the Charité - Universitätsmedizin Berlin between 2006 and 2018 were eligible for inclusion. We categorised into groups of mean potassium concentrations: < 3.0, 3.0-3.5, > 3.5-4.0, > 4.0-4.5, > 4.5-5.0, > 5.0-5.5, > 5.5 mmol/l and potassium variability: 1st, 2nd and ≥ 3rd standard deviation (SD). We analysed the association between the particular groups and in-hospital mortality and performed binary logistic regression analysis. Survival curves were performed according to Kaplan-Meier and tested by Log-Rank. In a subanalysis, the association between potassium supplementation and in-hospital mortality was investigated. RESULTS: In 53,248 ICU patients with 1,337,742 potassium values, the lowest mortality (3.7%) was observed in patients with mean potassium concentrations between > 3.5 and 4.0 mmol/l and a low potassium variability within the 1st SD. Binary logistic regression confirmed these results. In a subanalysis of 22,406 ICU patients (ICU admission: 2013-2018), 12,892 (57.5%) received oral and/or intravenous potassium supplementation. Potassium supplementation was associated with an increase in in-hospital mortality in potassium categories from > 3.5 to 4.5 mmol/l and in the 1st, 2nd and ≥ 3rd SD (p < 0.001 each). CONCLUSIONS: ICU patients may benefit from a target range between 3.5 and 4.0 mmol/l and a minimal potassium variability. Clear potassium target ranges have to be determined. Criteria for widely applied potassium supplementation should be critically discussed. Trial registration German Clinical Trials Register, DRKS00016411. Retrospectively registered 11 January 2019, http://www.drks.de/DRKS00016411.

[Why and How Should I Assess Frailty? A Guide for the Preoperative Anesthesia Clinic]. / Warum und wie sollte ich Frailty erfassen? ­ ein Ansatz für die Anästhesieambulanz.

Introduction: Frailty is a condition of decreased physiological reserves seen in approx. one third of elderly anesthesiological patients, and affecting many aspects of treatment as well as outcome. Although there are over 60 measurement instruments, frailty assessment is still poorly implemented. Understanding why and how to assess frailty is key to its implementation in preoperative anesthesia clinics. Method: After presenting the impact of perioperative frailty and the benefits of an early diagnosis on health related quality of life, we present an overview of the most important tools that can be used in the preoperative frailty assessment. Results: Early diagnosis offer several optimization opportunities for the perioperative period. The most efficient frailty assessment tools are presented and discussed, including physical, cognitive, and psychosocial aspects. Conclusion: Frailty assessments vary immensely in terms of required time, equipment, and expertise. We recommend at least one test for each domain of frailty, so as to obtain a more holistic view of the patient's physiological reserve. The implementation of an adequate and consistent preoperative frailty assessment has the potential to improve patient safety as well as short and long term outcomes.

Acetylcholinesterase inhibitors reduce neuroinflammation and -degeneration in the cortex and hippocampus of a surgery stress rat model.

Exogenous stress like tissue damage and pathogen invasion during surgical trauma could lead to a peripheral inflammatory response and induce neuroinflammation, which can result in postoperative cognitive dysfunction (POCD). The cholinergic anti-inflammatory pathway is a neurohumoral mechanism that plays a prominent role by suppressing the inflammatory response. Treatments with acetylcholinesterase inhibitors enhance cholinergic transmission and may therefore act as a potential approach to prevent neuroinflammation. In the presence or absence of acetylcholinesterase inhibitors, adult Wistar rats underwent surgery alone or were additionally treated with lipopolysaccharide (LPS). Physostigmine, which can overcome the blood-brain barrier or neostigmine acting only peripheral, served as acetylcholinesterase inhibitors. The expression of pro- and anti-inflammatory cytokines in the cortex, hippocampus, spleen and plasma was measured after 1 h, 24 h, 3 d and 7 d using Real-Time PCR, western blot analysis or cytometric bead array (CBA). Fluoro-Jade B staining of brain slices was employed to elucidate neurodegeneration. The activity of acetylcholinesterase was estimated using a spectrofluorometric method. Surgery accompanied by LPS-treatment led to increased IL-1beta gene and protein upregulation in the cortex and hippocampus but was significantly reduced by physostigmine and neostigmine. Furthermore, surgery in combination with LPS-treatment caused increased protein expression of IL-1, TNF-alpha and IL-10 in the spleen and plasma. Physostigmine and neostigmine significantly decreased the protein expression of IL-1 and TNF-alpha. Neuronal degeneration and the activity of acetylcholinesterase were elevated after surgery with LPS-treatment and reduced by physostigmine and neostigmine. Along with LPS-treatment, acetylcholinesterase inhibitors reduce the pro-inflammatory response as well as neurodegeneration after surgery in the cortex and hippocampus. This combination may represent a tool to break the pathogenesis of POCD.

Effect of empirical treatment with moxifloxacin and meropenem vs meropenem on sepsis-related organ dysfunction in patients with severe sepsis: a randomized trial.

CONTEXT: Early appropriate antimicrobial therapy leads to lower mortality rates associated with severe sepsis. The role of empirical combination therapy comprising at least 2 antibiotics of different mechanisms remains controversial. OBJECTIVE: To compare the effect of moxifloxacin and meropenem with the effect of meropenem alone on sepsis-related organ dysfunction. DESIGN, SETTING, AND PATIENTS: A randomized, open-label, parallel-group trial of 600 patients who fulfilled criteria for severe sepsis or septic shock (n = 298 for monotherapy and n = 302 for combination therapy). The trial was performed at 44 intensive care units in Germany from October 16, 2007, to March 23, 2010. The number of evaluable patients was 273 in the monotherapy group and 278 in the combination therapy group. INTERVENTIONS: Intravenous meropenem (1 g every 8 hours) and moxifloxacin (400 mg every 24 hours) or meropenem alone. The intervention was recommended for 7 days and up to a maximum of 14 days after randomization or until discharge from the intensive care unit or death, whichever occurred first. MAIN OUTCOME MEASURE: Degree of organ failure (mean of daily total Sequential Organ Failure Assessment [SOFA] scores over 14 days; score range: 0-24 points with higher scores indicating worse organ failure); secondary outcome: 28-day and 90-day all-cause mortality. Survivors were followed up for 90 days. RESULTS: Among 551 evaluable patients, there was no statistically significant difference in mean SOFA score between the meropenem and moxifloxacin group (8.3 points; 95% CI, 7.8-8.8 points) and the meropenem alone group (7.9 points; 95% CI, 7.5-8.4 points) (P = .36). The rates for 28-day and 90-day mortality also were not statistically significantly different. By day 28, there were 66 deaths (23.9%; 95% CI, 19.0%-29.4%) in the combination therapy group compared with 59 deaths (21.9%; 95% CI, 17.1%-27.4%) in the monotherapy group (P = .58). By day 90, there were 96 deaths (35.3%; 95% CI, 29.6%-41.3%) in the combination therapy group compared with 84 deaths (32.1%; 95% CI, 26.5%-38.1%) in the monotherapy group (P = .43). CONCLUSION: Among adult patients with severe sepsis, treatment with combined meropenem and moxifloxacin compared with meropenem alone did not result in less organ failure. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00534287.

[Emergency caesarean section and interdisciplinary emergency concepts for the delivery room - "What to do if it is urgent?"]. / Notsectio und interdisziplinäre Notfallkonzepte im Kreißsaal - "Und wenn es schnell gehen soll?"

Resolute and rapid action in obstetric emergencies is essential for the child and/or maternal survival. Therefore emergency caesarean section and the emergency actions for peripartal haemorrhage, shoulder dystocia, fetal bradycardia, hypertension and embolism should be interdisciplinarily coordinated. Interdisciplinary emergency concepts for the major complications could help to optimise their therapy taking structural conditions and legal requirements into account. Emergency concepts should include the alarm- procedure, communication, logistics, the priority steps in therapy as well as the analysis of the passed obstetric emergency. A regular interdisciplinary training of the major obstetric emergencies may help to avoid unnecessary loss of time.

Psychophysiological responses in patients with fibromyalgia syndrome.

Physical and emotional stress and altered reactivity of the autonomic nervous system have been implicated in the development and maintenance of fibromyalgia syndrome (FMS). This study investigated blood pressure, heart rate (HR), skin conductance levels (SCL), and surface electromyograms (EMG) from the trapezius muscle in 30 FMS patients and 30 age- and sex-matched healthy controls (HCs). All measures were continuously recorded during baseline (BL), social conflict, mental arithmetic, and relaxation tasks. The FMS patients showed significantly higher stress ratings and self-reported stress responses. Baseline EMG levels were significantly lower, and BL HR was significantly elevated. During both stress tasks, HR reactivity was significantly lower, and SCL reactivity was significantly higher in the FMS group. This pattern of low BL muscle tension and high BL HR, along with low HR and high SCL reactivity to stress, is discrepant to other chronic pain syndromes and suggests unique psychophysiological features associated with FMS. Several potential mechanisms for these psychophysiological responses are discussed.