Atrial arrhythmias and acute pericarditis triggered by bleach ingestion-associated oesophageal perforation: a case report

Background

Acute pericarditis due to oesophageal perforation and caustic injury is a rare presentation of bleach ingestion. Cardiac arrhythmias such as atrial fibrillation and atrial flutter have been associated with certain aetiologies of acute pericarditis. This case report presents a unique occurrence of acute pericarditis following bleach ingestion and intermittent atrial fibrillation and atrial flutter triggered by liquid intake.

Case summary

A 36-year-old male with no significant past medical history presented after attempted suicide by ingesting bleach. He had acute pericarditis resulting from caustic oesophageal perforation and extensive mediastinal injury. In the following days, he developed recurrent episodes of atrial fibrillation and atrial flutter following fluid intake, prompting treatment with metoprolol. On Day 5 of hospitalization, he underwent an oesophagogram and developed persistent atrial arrhythmia with haemodynamic instability requiring cardioversion. He underwent thoracoscopic surgery to address the oesophageal injury. A jejunostomy tube was placed and he had complete resolution of his recurrent atrial arrhythmia.

Discussion

This case highlights a rare presentation of atrial arrhythmias and acute pericarditis caused by corrosive oesophageal injury due to bleach ingestion. The effective management of such cases necessitates a co-ordinated approach, involving the collaboration of cardiothoracic surgeons, cardiologists, and critical care specialists, with the aim of enhancing patient outcomes and mitigating the life-threatening risks associated with oesophageal perforation and cardiac arrhythmias. Furthermore, this case underscores the imperative for further research to better understand the relationship between traumatic acute pericarditis and atrial arrhythmias, offering the potential for improved patient care in these intricate clinical scenarios.

Urban-rural differences in hypertension prevalence, blood pressure control, and systolic blood pressure levels

Higher rates of cardiovascular events have been observed among rural residents compared with urban. Hypertension and lack of blood pressure (BP) control are risk factors for cardiovascular events. We compared the prevalence of hypertension and controlled BP, and the distribution of systolic blood pressure (SBP), by urban-rural residence. Participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, a prospective cohort of Black and White adults aged ≥45 years, were categorized as either urban, large rural, or small-isolated rural, by using the Rural-Urban Commuting Area (RUCA) categorization B system. Oucomes were hypertension prevalence (BP ≥ 140/90 mmHg or antihypertensive use), BP control (BP < 140/90 among participants on antihypertensive medication), and the distribution of SBP. Counfounders were age, race, sex, antihypertensive medication use, and US Census Bureau division. The analysis included 26,133 participants (80.3% urban, 11.6% large-rural, 8.2% small-isolated rural). The unadjusted prevalence of hypertension was not different between groups. However, after adjustment, the odds of hypertension was higher among participants in the large rural group (odds ratio [OR] 1.17; 95% confidence interval [CI], 1.08-1.27) and small-isolated rural group (OR 1.19; 95% CI, 1.08-1.30), compared with the urban group. There was no evidence of an adjusted difference in BP control for those taking antihypertensive medications. Adjusted differences in SBP were greater for both rural groups, compared with urban, at the higher percentiles of SBP. Rural residence was associated with a higher adjusted odds of hypertension and higher SBP.

Cardiogenic shock in a woman with a mitochondrial cardiomyopathy: a case report

Background

Mitochondrial cardiomyopathy (MCM) is an alteration in cardiac structure and function caused by gene mutations or deletions affecting components of the mitochondrial respiratory chain. We report a case of MCM presenting as cardiogenic shock, ultimately requiring left ventricular assist device (LVAD) placement.

Case summary

A 35-year-old woman with chronic weakness and non-ischaemic cardiomyopathy, on home dobutamine, was referred to our institution for heart transplantation evaluation. She was admitted to the hospital for suspected cardiogenic shock after laboratory tests revealed a lactate level of 5.4 mmol/L (ref: 0.5-2.2 mmol/L). Her hospital course was complicated by persistently undulating lactate levels (0.2-8.6 mmol/L) that increased with exertion and did not correlate with mixed venous oxygen saturation measurements obtained from a pulmonary artery catheter. Electrodiagnostic testing demonstrated a proximal appendicular and axial myopathy. A left deltoid muscle biopsy was performed that demonstrated evidence of a mitochondrial disease on light and electron microscopy. Muscle genetic testing revealed two large-scale mitochondrial deoxyribonucleic acid sequence deletions, confirming the diagnosis of MCM. She subsequently underwent LVAD placement, which was complicated by significant right ventricular failure requiring early mechanical support. She was ultimately discharged home with chronic inotropic support.

Discussion

Mitochondrial cardiomyopathy in adults is a diagnostic and therapeutic challenge. Prompt diagnosis should be made in patients with unknown causes of heart failure via skeletal muscle histopathology guided by electrodiagnostic studies, and targeted genetic testing in affected tissue. Outcomes in adult MCM patients who receive an LVAD are unknown and warrant further investigation.

Percutaneous debulking of tricuspid valve endocarditis in severe COVID-19 pneumonia after prolonged venovenous extracorporeal membrane oxygenation with right-ventricular support: a case series

Background

Over the past 2 years, the utilization of venovenous extracorporeal membrane oxygenation (VV-ECMO) for the treatment of coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS) has increased. While supporting respiratory function, VV-ECMO requires large-bore indwelling venous cannulas, which risk bleeding and infections, including endocarditis.

Case summary

We describe two adults hospitalized for COVID-19 pneumonia who developed ARDS and right-ventricular failure, requiring VV-ECMO and ProtekDuo cannulation. After over 100 days with these devices, both patients developed tricuspid valve vegetations. Our first patient was decannulated from ECMO and discharged, but re-presented with a segmental pulmonary embolism and tricuspid mass. The Inari FlowTriver system was chosen to percutaneously remove both the tricuspid mass and pulmonary thromboembolism. Pathological examination of the mass demonstrated Candida albicans endocarditis in the setting of Candida fungemia. Our second patient developed a tricuspid valve vegetation which was also removed with the FlowTriever system. Pathological examination demonstrated endocarditis consistent with Pseudomonas aeruginosa in the setting of Pseudomonas bacteremia. Both patients experienced resolution of fungemia and bacteremia after percutaneous vegetation removal. After ECMO decannulation and percutaneous debulking, both patients experienced prolonged hospital stays for ventilator weaning and were eventually discharged with supplemental oxygen.

Discussion

VV-ECMO and right-ventricular support devices are invasive and create various risks, including bloodstream infection and infective endocarditis. Percutaneous debulking of valvular vegetations associated with these right-sided indwelling devices may be an effective means of infection source control. It is unclear whether prolonged use of VV-ECMO provides a mortality benefit in COVID-19 ARDS.

Risk of Postdischarge Bleeding From Dual Antiplatelet Therapy After Percutaneous Coronary Intervention Among US Black and White Adults

Background Dual antiplatelet therapy after percutaneous coronary intervention reduces myocardial infarctions but increases bleeding. The risk of bleeding may be higher among Black patients for unknown reasons. Bleeding risk scores have not been validated among Black patients. We assessed the difference in bleeding risk between Black and White patients along with the performance of the Predicting Bleeding Complications in Patients Undergoing Stent Implantation and Subsequent Dual Anti Platelet Therapy, Patterns of Nonadherence to Antiplatelet Regimens in Stented Patients, and Academic Research Consortium for High Bleeding Risk scores among both groups. Methods and Results This was a single-center prospective study of patients who underwent percutaneous coronary intervention (2014-2019) and were followed for 1 year. The outcome was postdischarge Bleeding Academic Research Consortium 2 to 5 bleeding. Incidence rates were reported. Cox proportional hazards models measured the effect of self-reported Black race on bleeding and determined the predictors of bleeding among 19 a priori variables. The 3 risk scores were assessed among Black and White patients separately using the Harrell concordance index. Of 1529 included patients, 342 (22.4%) self-reported as being Black race. Unadjusted bleeding rates were 22.7 per 100 person-years among Black patients versus 16.3 among White patients (hazard ratio, 1.41 [95% CI, 1.00-2.00], P=0.052). Predictors of bleeding were age, glomerular filtration rate <30 mL/min per 1.73 m2, prior bleeding, ticagrelor or prasugrel use, and anticoagulant use. Among Black and White patients, respectively, the C-indexes were the following: 0.644 versus 0.600 for Predicting Bleeding Complications in Patients Undergoing Stent Implantation and Subsequent Dual Anti Platelet Therapy (P<0.001 for both), 0.620 versus 0.612 for Patterns of Nonadherence to Antiplatelet Regimens in Stented Patients (P=0.003 and P<0.001, respectively), and 0.600 versus 0.598 for Academic Research Consortium for High Bleeding Risk (P=0.006 and P<0.001, respectively). Conclusions The risk of dual antiplatelet therapy-associated postdischarge Bleeding Academic Research Consortium 2 to 5 bleeding was not significantly different between self-reported Black and White patients. Bleeding risk scores performed similarly among both groups.

Establishing Care Post Discharge Following a Heart Failure Hospitalization in an Uninsured Heart Failure Population

Multidisciplinary interprofessional outpatient care improves mortality for patients with heart failure (HF) but is underutilized. We sought to identify factors associated with not establishing outpatient care among uninsured individuals with HF. We included uninsured individuals referred to an interprofessional clinic after a hospitalization with HF from 2016 to 2019. The primary outcome was establishing care, defined as presenting to clinic within 7 days of discharge from the hospital. We constructed multivariable adjusted logistic regression models to identify predictors of establishing care. A total of 698 uninsured individuals were referred, of whom 583 (84%) established care. Mean age was 49.5 ± 11 years, 15% were rural-dwelling, 59% were black, and 31% were female. Black participants who were rural-dwelling (adusted odds ratio [aOR] 0.07, 95% confidence interval [CI] 0.03 to 0.17) or reported alcohol use (aOR 0.32, 95% CI 0.16 to 0.64) had lower odds of establishing care. White participants who were rural-dwelling (aOR 2.63, 95% CI 1.17 to 5.90) had higher odds of establishing care. Uninsured black individuals with HF who live in rural communities or who are active alcohol users represent a group that is at high risk of not establishing outpatient follow-up after a hospitalization with HF. Efforts to reduce this disparity are warranted to improve health outcomes in this population.

Genetic European Ancestry and Incident Diabetes in Black Individuals: Insights From the SPRINT Trial

BACKGROUND

Black individuals have high incident diabetes risk, despite having paradoxically lower triglyceride and higher HDL (high-density lipoprotein) cholesterol levels. The basis of this is poorly understood. We evaluated the participants of SPRINT (Systolic Blood Pressure Intervention Trial) to assess the association of estimated European genetic ancestry with the risk of incident diabetes in self-identified Black individuals.

METHODS

Self-identified non-Hispanic Black SPRINT participants free of diabetes at baseline were included. Black participants were stratified into tertiles (T1-T3) of European ancestry proportions estimated using 106 biallelic ancestry informative genetic markers. The multivariable-adjusted association of European ancestry proportion with indices of baseline metabolic syndrome (ie, fasting plasma glucose, triglycerides, HDL cholesterol, body mass index, and blood pressure) was assessed. Multivariable-adjusted Cox regression determined the risk of incident diabetes (fasting plasma glucose ≥126 mg/dL or self-reported diabetes treatment) across tertiles of European ancestry proportion.

RESULTS

Among 2466 Black SPRINT participants, a higher European ancestry proportion was independently associated with higher baseline triglyceride and lower HDL cholesterol levels (P<0.001 for both). European ancestry proportion was not associated with baseline fasting plasma glucose, body mass index, and blood pressure (P>0.05). Compared with the first tertile, those in the second (hazard ratio, 0.64 [95% CI, 0.45-0.90]) and third tertiles (hazard ratio, 0.61 [95% CI, 0.44-0.89]) of the European ancestry proportion had a lower risk of incident diabetes. A 5% point higher European ancestry was associated with a 29% lower risk of incident diabetes (hazard ratio, 0.71 [95% CI, 0.55-0.93]). There was no evidence of a differential association between the European ancestry proportion tertiles and incident diabetes between those randomized to intensive versus standard blood pressure treatment.

CONCLUSIONS

The higher risk of incident diabetes in Black individuals may have genetic determinants in addition to adverse social factors. Further research may help understand the interplay between biological and social determinants of cardiometabolic health in Black individuals. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01206062.

Insulin Resistance and Cardiometabolic Risk Profile Among Nondiabetic American Young Adults: Insights From NHANES

BACKGROUND

The burden of insulin resistance (IR) among young American adults has not been previously assessed. We evaluated (1) the prevalence and trends of IR and cardiometabolic risk factors and (2) the association between measures of adiposity and IR among adults 18 to 44 years of age without diabetes and preexisting cardiovascular disease.

METHODS

Cross-sectional survey data from six consecutive National Health and Nutrition Examination Survey (2007-2008 to 2017-2018) cycles were analyzed. IR was defined by the homeostatic model assessment for IR (HOMA-IR) of ≥2.5. The temporal trends of IR, cardiometabolic risk factors, and the relationship between IR and measures of adiposity were assessed using multivariable-adjusted regression models.

RESULTS

Among 6247 young adults 18 to 44 years of age, the prevalence of IR was 44.8% (95% CI: 42.0%-47.6%) in 2007-2010 and 40.3% (95% CI: 36.4%-44.2%) in 2015-2018 (P for trend = 0.07). There was a modest association of HOMA-IR with higher body mass index (BMI), waist circumference, total lean fat mass, and total and localized fat mass (all Ps < 0.001). Participants with IR had a higher prevalence of hypertension [31.3% (95% CI: 29.2%-33.5%) vs 14.7% (95% CI: 13.2%-16.2%)], hypercholesterolemia [16.0% (95% CI: 12.4%-19.5%) vs 7.0% (95% CI: 5.8%-8.5%)], obesity [56.6% (95% CI: 53.9%-59.3%) vs 14.7% (95% CI: 13.0%-16.5%)], and poor physical activity levels [18.3% (95% CI: 16.4%-20.2%) vs 11.7% (95%CI: 10.3-13.1%)] compared to participants without IR (all Ps < 0.05).

CONCLUSIONS

Four-in-10 young American adults have IR, which occurs in a cluster with cardiometabolic risk factors. Nearly half of young adults with IR are nonobese. Screening efforts for IR irrespective of BMI may be required.

Hybrid cardiac rehabilitation - The state of the science and the way forward

Cardiac rehabilitation (CR) improves exercise capacity and health-related quality of life (HRQoL) in a broad range of patients, including those with coronary artery disease, heart failure (HF), after heart valve surgery, and after heart transplantation. Unfortunately, in traditional center-based CR programs participation and adherence are low. A hybrid model of CR, combining center-based and home-based CR services, has been proposed and is currently being studied as a potential way to help bridge the participation gap, while maintaining the beneficial patient outcomes from CR. However, the ideal composition of a hybrid CR program has not been universally agreed upon. In the present review, we define hybrid CR as any combination of supervised center-based and monitored home-based exercise, where at least two of the core components of CR are addressed. Using this definition, we searched for studies comparing hybrid CR with: (1) traditional center-based CR among CAD patients, (2) usual care among CAD patients, and (3) usual care among HF patients. We found nine studies which fit both our definition and comparison groups. The structure of the hybrid CR programs differed for each study, but typically began with a center-based component lasting 2-11 weeks and transitioned to a home-based component lasting 10-22 weeks, with 3-5 exercise sessions per week composed of either walking (usually with a treadmill) or cycling for 25-35 min at 60-75% maximal heart rate. Patients recorded data from home exercise sessions, via either a digital heart rate monitor or accelerometer, into logbooks which were reviewed by a therapist at specified intervals (often via telephone). Counseling on risk factor management was predominantly provided during the center-based component. In these studies, hybrid CR led to similar short-term outcomes compared to traditional CR in patients with coronary artery disease (CAD), as well as increased adherence and reduced delivery costs. Compared with usual care, in patients with CAD, hybrid CR reduced cardiovascular events, and improved lipid profiles, exercise capacity, and HRQoL. In patients with HF, compared with usual care, hybrid CR improved physical function, exercise capacity, and HRQoL. Ongoing studies may clarify the combination of center-based and home-based CR which produces superior outcomes, and may also better define the role that technology should play in CR interventions.

Outcomes of Individuals With and Without Heart Failure Presenting With Acute Coronary Syndrome

Major adverse cardiac event (MACE) and bleeding risks following percutaneous coronary intervention (PCI) for acute coronary syndromes (ACS) are not well defined in individuals with heart failure (HF). We followed 1,145 individuals in the Pharmacogenomic Resource to improve Medication Effectiveness Genotype Guided Antiplatelet Therapy cohort for MACE and bleeding events following PCI for ACS. We constructed Cox proportional hazards models to compare MACE and bleeding in those with versus without HF, adjusting for sociodemographics, comorbidities, and medications. We also determined predictors of MACE and bleeding events in both groups. 370 (32%) individuals did and 775 (68%) did not have HF prior to PCI. Mean age was 61.7 ± 12.2 years, 31% were female, and 24% were African American. After a median follow-up of 0.78 years, individuals with HF had higher rates of MACE compared to those without HF (48 vs. 24 events per 100 person years) which remained significant after multivariable adjustment (hazard ratio [HR] 1.31, 95% confidence interval [CI] 1.00 to 1.72). Similarly, bleeding was higher in those with versus without HF (22 vs. 11 events per 100 person years), although this was no longer statistically significant after multivariable adjustment (HR 1.29, 95% CI 0.86 to 1.93). Diabetes and peripheral vascular disease were predictors of MACE, and end-stage renal disease was a predictor of bleeding among participants with HF. MACE risk is higher in individuals with versus without HF following PCI for ACS. However, the risk of bleeding, especially among those with end-stage renal disease , must be considered when determining post-PCI anticoagulant strategies.

Severe myocardial ischemia in a patient with diabetes mellitus and left bundle branch block

We present the case of a 69-year-old woman with diabetes mellitus, left bundle branch block, and obesity who develops cardiogenic shock after undergoing myocardial perfusion imaging and diagnostic left heart catheterization, but prior to coronary revascularization. This case highlights the risk of cardiac decompensation awaiting surgery in patients with multivessel coronary artery disease. It also emphasizes the subtleties involved in imaging patients with diabetes mellitus and left bundle branch block, as well as the risk of developing complete heart block in the setting of ischemia with underlying conduction disease.

Geographic Variation in Racial Disparities in Health and Coronavirus Disease-2019 (COVID-19) Mortality

Objective

To evaluate the race-stratified state-level prevalence of health determinants and the racial disparities in coronavirus disease 2019 (COVID-19) cumulative incidence and mortality in the United States.

Patients and Methods

The age-adjusted race-stratified prevalence of comorbidities (hypertension, diabetes, dyslipidemia, and obesity), preexisting medical conditions (pulmonary disease, heart disease, stroke, kidney disease, and malignant neoplasm), poor health behaviors (smoking, alcohol abuse, and physical inactivity), and adverse socioeconomic factors (education, household income, and health insurance) was computed in 435,139 American adult participants from the 2017 Behavioral Risk Factor Surveillance System survey. Correlation was assessed between health determinants and the race-stratified COVID-19 crude mortality rate and infection-fatality ratio computed from respective state public health departments in 47 states.

Results

Blacks had a higher prevalence of comorbidities (63.3%; 95% CI, 62.4% to 64.2% vs 55.1%; 95% CI, 54.7% to 55.5%) and adverse socioeconomic factors (47.0%; 95% CI, 46.0% to 47.9% vs 30.9%; 95% CI, 30.6% to 31.3%) than did whites. The prevalence of preexisting medical conditions was similar in blacks (30.4%; 95% CI, 28.8% to 32.1%) and whites (30.8%; 95% CI, 30.2% to 31.4%). The prevalence of poor health behaviors was higher in whites (57.2%; 95% CI, 56.3% to 58.0%) than in blacks (50.2%; 95% CI,46.2% to 54.2%). Comorbidities and adverse socioeconomic factors were highest in the southern region, and poor health behaviors were highest in the western region. The cumulative incidence rate (per 100,000 persons) was 3-fold higher in blacks (1546.4) than in whites (540.4). The crude mortality rate (per 100,000 persons) was 2-fold higher in blacks (83.2) than in whites (33.2). However, the infection-fatality ratio (per 100 cases) was similar in whites (6.2) and blacks (5.4). Within racial groups, the geographic distribution of health determinants did not correlate with the state-level COVID-19 mortality and infection-fatality ratio (P>.05 for all).

Conclusion

Racial disparities in COVID-19 are largely driven by the higher cumulative incidence of infection in blacks. There is a discordance between the geographic dispersion of COVID-19 mortality and the regional distribution of health determinants.

Massive pulmonary embolism in a COVID-19 patient: a case report

Background

Myocardial injury is associated with excess mortality in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, and the mechanisms of injury are diverse. Coagulopathy associated with this infection may have unique cardiovascular implications.

Case summary

We present a case of 62-year-old male who presented after experiencing syncope and cardiac arrest. Given the clinical presentation and electrocardiographic findings, there was concern for acute coronary syndrome. However, coronary angiogram did not reveal significant coronary obstruction. Due to the unclear nature of his presentation, a bedside echocardiogram was rapidly performed and was indicative of right ventricular strain. Due to these findings, a pulmonary angiogram was performed that revealed massive pulmonary embolism. He successfully underwent catheter-directed thrombolysis and, after a prolonged hospital stay, was discharged home on lifelong anticoagulation.

Discussion

The impact of coronavirus disease-2019 (COVID-19) on the cardiovascular system has been prominent and multifaceted. COVID-19 can have wide-ranging effects on the cardiovascular system due to coagulopathy with resultant venous and arterial thrombo-embolism. Due to the critical condition of many patients affected by COVID-19, imaging for thrombo-embolic events is often delayed. With the use of bedside echocardiogram, observation of right ventricular strain may be critical in raising suspicion for pulmonary embolism, especially when atypical features are noted on electrocardiogram.

Stress-Induced Cardiomyopathy Precipitated by COVID-19 and Influenza A Coinfection

Myocardial injury is associated with excess mortality in severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infections, but the mechanisms of injury are diverse. We describe a case of stress-induced cardiomyopathy in the setting of SARS-CoV-2 and influenza A coinfection. (Level of Difficulty: Intermediate.)

A Case of Heart Failure in a Patient With Systemic Lupus Erythematosus

Patients with systemic lupus erythematosus (SLE) can present with multiple cardiovascular pathologies, including pulmonary hypertension, valvular disease, pericarditis, myocarditis, and premature atherosclerosis. SLE medications can also cause cardiovascular side effects. We present a patient who developed a severe cardiomyopathy secondary to the hydroxychloroquine prescribed to treat her SLE. (Level of Difficulty: Beginner.).

[Optimization of criteria for activation of trauma teams : Avoidance of overtriage and undertriage]

INTRODUCTION

Severely injured patients are supposed to be admitted to hospital via the trauma room. Appropriate criteria are contained in the S3 guidelines on the treatment of patients with severe/multiple injuries (S3-GL); however, some of these criteria require scarce hospital resources while the patients then often clinically present as uninjured. There are tendencies to streamline the trauma team activation criteria (TTAC); however, additional undertriage must be avoided. A study group of the emergency, intensive care medicine and treatment of the severely injured section (NIS) is in the process of optimizing the TTAC for the German trauma system.

MATERIAL AND METHODS

In order to solve the objective the following multi-step approach is necessary: a) definition of patients who potentially benefit from TTA, b) verification of the definition in the TraumaRegister DGU® (TR-DGU), c) carrying out a prospective, multicenter study in order to determine overtriage and undertriage, thereby validating the activation criteria and d) revision of the current TTAC.

RESULTS

This article summarizes the consensus criteria of the group assumed to be capable of identifying patients who potentially benefit from TTA. These criteria are used to test if TTA was justified in a specific case; however, as the TTCA of the S3-GL are not fully incorporated into the TR-DGU dataset and because cases must also be considered which were not subject to trauma room treatment and therefore were not included in the TR-DGU, it is necessary to perform a prospective full survey of all individuals in order to be able to measure overtriage and undertriage.

CONCLUSION

Currently, the TR-DGU can only provide limited evidence on the quality of the TTAC recommended in Germany. This problem has been recognized and will be solved by conducting a prospective DGU-supported study, the results of which can be used to improve the TR-DGU dataset in order to enable further considerations on the quality of care (e. g. composition and size of the trauma team).

[Disseminated nocardiosis : Diagnostic challenge]

Nocardiosis is a rarely found bacterial infection in Europe which can particularly affect immunocompromized patients. Localized infections of the dermis and lungs, as well as disseminated infections can be observed. Suspicion of nocardiosis should be reported to the microbiological laboratory so that goal-directed molecular genetic techniques and extended cultivation can be implemented for identification of the causative agent. A multitude of antibiotics can be used for successful therapy but the duration of therapy must be extended over 6-12 months. The mortality of disseminated infections ranges between 15-85% depending on the underlying immune status of the patient. The polymorphic appearance of nocardiosis is described based on the case of an intensive care patient.

Multicenter assessment of CSF-phosphorylated tau for the prediction of conversion of MCI

BACKGROUND

The measurement of hyperphosphorylated tau (p-tau) in CSF has been proposed as a biomarker candidate for the prediction of Alzheimer disease (AD) in patients with mild cognitive impairment (MCI). However, a standard quantitative criterion of p-tau has not been evaluated.

OBJECTIVE

To assess in a multicenter study the predictive accuracy of an a priori defined criterion of tau phosphorylated at threonine 231 (p-tau(231)) for the prediction of conversion from MCI to AD during a short-term observation interval.

METHODS

The study included 43 MCI converters, 45 stable MCI (average follow-up interval = 1.5 years), and 57 healthy controls (at baseline only). Subjects were recruited at four international expert sites in a retrospective study design. Cox regression models stratified according to center were used to predict conversion status. Bootstrapped 95% CIs of classification accuracy were computed.

RESULTS

Levels of p-tau(231) were a significant predictor of conversion (B = 0.026, p = 0.001), independent of age, gender, Mini-Mental State Examination, and ApoE genotype. For an a priori-defined cutoff point (27.32 pg/mL), sensitivity ranged between 66.7 and 100% and specificity between 66.7 and 77.8% among centers. The bootstrapped mean percentage of correctly classified cases was 79.95% (95% CI = 79.9 to 80.00%). Post hoc defined cutoff values yielded a mean bootstrapped classification accuracy of 80.45% (95% CI = 80.24 to 80.76%).

CONCLUSIONS

An a priori defined cutoff value of p-tau(231) yields relatively stable results across centers, suggesting a good feasibility of a standard criterion of p-tau(231) for the prediction of Alzheimer disease.

Blutungen während der Schwangerschaft

Hemorrhaging during pregnancy is often fulminant and life-threatening for mother and child. Of maternal deaths occurring during pregnancy, 25% are caused by hemorrhaging. All physicians involved in the interdisciplinary treatment of hemorrhaging during pregnancy need to be familiar with the specific pathophysiology of hemostatic changes during pregnancy, e.g. elevated hemostatic capacity, reduced anti-coagulation activity and severe alterations of the fibrinolysis system. Therapists must be able to perform a consequent, goal-directed interdisciplinary approach to prevent adverse maternal and fetal outcomes. The major issues of therapy are causal obstetric treatment of the bleeding, early detection and therapy of hyperfibrinolysis, optimization of fibrinogen and platelet levels and knowledge of the possibilities of a targeted coagulation therapy.

Durch Thrombelastographie gesteuertes perioperatives Gerinnungsmanagement

Uncontrolled bleeding is one of the main reasons for a lethal outcome of severe trauma. Loss, consumption and dilution of clotting factors and platelets induce a complex acquired coagulopathy. Beside surgical control of bleeding, early and precise coagulation therapy is essential for successful treatment. We report on a patient whose life-threatening bleeding and perioperative coagulopathy after a knife injury to the aorta was successfully treated by surgical control of the bleeding and subsequent targeted coagulation therapy with factor concentrates and fresh-frozen plasma. The coagulopathy was diagnosed and managed by means of bed-side thrombelastography.

Frischplasma und Faktorenkonzentrate zur Therapie der perioperativen Koagulopathie

Acquired, perioperative coagulopathy often develops due to acute bleeding. In the case of primarily healthy patients with normal bone marrow and liver functions, a lack of coagulation factors initiates coagulopathy before secondary thrombopenia arises. Replacement of coagulation factors can be performed by infusion of fresh plasma (single donor or pooled plasma) or concentrates of clotting factors. Fresh plasma as well as concentrates of clotting factors available in German-speaking countries are of high quality and fulfil all safety standards. Undesirable side-effects due to transmission of infections and immunological reactions are--in all probability--more uncommon for virus-inactivated plasma and clotting factors than for single donor plasma. In contrast, thromboembolic complications are unlikely when using fresh frozen plasma, because it contains a balanced ratio of pro-coagulatory and anti-coagulatory factors. For virus-inactivated pooled plasma and concentrates of clotting factors, sporadic reports of thromboembolic events have been published. Concentrates of clotting factors can be stored easily and are rapidly prepared for use. In contrast, fresh frozen plasma has to be thawed before application leading to a significant delay in the schedule. During activated hemostasis, the half-life of clotting factors is significantly reduced in comparison to a stable physiological situation. In the case of perioperative coagulopathy higher dosages of fresh plasma and clotting factors than those recommended in published guidelines are often necessary for successful treatment. When using fresh plasma for coagulation therapy the resulting volume load must be considered. In conclusion, a modern concept of perioperative coagulation management should include fresh plasma as well as concentrates of clotting factors. The anesthetist should be familiar with the available components and be able to consider and adapt them to the individual situation.

[Safety of plasma-derived factor concentrates: an example of pharmacovigilance with fibrinogen and factor XIII-concentrate]

Elaborate measures for donor selection and the production of clotting factor concentrates have led to a high safety standard of these products. A multimodal approach to eliminate unwanted contents has been established by strict screening of possible donors and various inactivation procedures within the production process. The systematic registration of adverse events shows very few allergic and nonallergic reactions to plasma derived clotting factor concentrates. In none of the registered cases transmission of infections could be verified. The worldwide registration of such adverse events is not yet sufficiently established, since adequate structures are lacking in some countries. According to estimates, far less than half of occurring adverse events are registered in Germany. A European solution in the form of an official register is about to be introduced.

Sicherheit von Faktorenkonzentraten aus Plasma

Aufwändige Maßnahmen zur Spenderauswahl und Herstellung von Gerinnungsfaktorenkonzentraten haben inzwischen zu einem sehr hohen Sicherheitsstandard dieser Präparate geführt. Dabei wird sowohl bei der Spenderauswahl durch hohe Selektion als auch beim Herstellungsprozess durch verschiedene Inaktivierungsverfahren eine multimodale Vorgehensweise zur Elimination unerwünschter Inhaltsstoffe angewendet. Die systematische Erfassung von unerwünschten Arzneimittelwirkungen zeigt in den vergangenen Jahren eine sehr geringe Zahl an allergischen und nicht allergischen Reaktionen auf Gerinnungsfaktorkonzentrate aus Plasma. Die Übertragung von Infektionen konnte bis jetzt in keinem Fall sicher nachgewiesen werden. Die weltweite Registrierung solcher Nebenwirkungen ist noch nicht ausreichend umgesetzt, da in einigen Ländern entsprechende Strukturen fehlen. Schätzungen zufolge werden in Deutschland weit weniger als die Hälfte der unerwünschten Arzneimittelwirkungen gemeldet. Eine europaweite Lösung in Form eines behördlich geführten Registers soll eingeführt werden.

Safety of plasma-derived factor concentrates

Elaborate measures for donor selection and the production of clotting factor concentrates have led to a high safety standard of these products. A multimodal approach to eliminate unwanted contents has been established by strict screening of possible donors and various inactivation procedures within the production process. The systematic registration of adverse events shows very few allergic and nonallergic reactions to plasma derived clotting factor concentrates. In none of the registered cases transmission of infections could be verified. The worldwide registration of such adverse events is not yet sufficiently established, since adequate structures are lacking in some countries. According to estimates, far less than half of occurring adverse events are registered in Germany. A European solution in the form of an official register is about to be introduced.

[High dose fibrinogen administration for acute therapy of coagulopathy during massive perioperative transfusion]

During acute and severe perioperative bleeding a coagulopathy due to depletion, consumption and dilution of clotting factors and thrombocytes may occur. Diagnosis and therapy of such a coagulopathy should take place immediately. We report two cases of acute coagulopathy during perioperative bleeding and massive transfusion, which were treated successfully by administration of high dose fibrinogen concentrate. Diagnosis and treatment control were performed by thrombelastography.

[Frequency of intervention and risk factors in monitored anesthesia care in ophthalmic surgery -- a retrospective analysis]

BACKGROUND

Patients for ophthalmic surgery have an average age of 70 - 75 years and frequently suffer from cardiopulmonary disease. Despite the fact that only local anesthesia is applied, these patients often receive monitored anesthesia care. Aims of this study were to determine the frequency of drug interventions during monitored anesthesia care and to identify risk factors for treatment.

PATIENTS AND METHODS

In a retrospective study, preoperative history and anaesthetic records of 404 patients who had received monitored anesthesia care in a university hospital were analyzed for patient data, preoperative diagnoses and intraoperative anesthesiological interventions.

RESULTS

Patients were 70 +/- 12 years old and had a high co-morbidity (63 % ASA-classification 3), especially an increased cardiopulmonary risk. 50 % of all patients received a drug intervention. 41 % were given an antihypertonic agent intraoperatively and 17 % received other forms of drug treatment (e. g. insulin therapy, infusion of electrolytes, antiemetics). In 2,5 % of the cases severe cardiovascular complications occurred which needed treatment (severe arrhythmias, hypertensive crisis, severe hypotension with need for catecholamine therapy). The two parameters "arterial hypertension" (54 % intervention frequency vs. 35 % without arterial hypertension) and the surgical procedure of "pars plana vitrectomy" (58 % intervention frequency vs. 41 % for cataract surgery) were associated with a significantly increased frequency for intraoperative interventions.

CONCLUSIONS

The high intervention frequency for a variety of complications, especially of cardiovascular nature, advises the presence of a physician during ophthalmic operations who is trained to control such emergency situations.

Sevoflurane but not isoflurane can reduce prostacyclin production of endothelial cells

BACKGROUND AND OBJECTIVE

Little is known about the interaction of newer volatile anaesthetics with endothelial eicosanoid production. Sevoflurane may possibly reduce prostacyclin formation. Thus, we compared the influences of sevoflurane and isoflurane on endothelial prostacyclin production.

METHODS

Production of prostacyclin of human umbilical vein endothelial cells was measured by the ELISA technique under basal conditions and after stimulation with calcium ionophore A 23187 10 micromol or histamine 0.1 micromol in the absence and presence of 1 and 2 minimal alveolar concentrations (MAC) of sevoflurane or isoflurane.

RESULTS

The basal production of prostacyclin was unaffected by the volatile anaesthetics. Stimulation of endothelial cells increased prostacyclin formation 3-5-fold. Sevoflurane at 2 MAC, but not at 1 MAC, could reduce stimulated prostacyclin production by about half (P < 0.05). Isoflurane had no inhibitory effect. Inhibition of cyclo-oxygenase function by acetylsalicylic acid abolished the induced burst of prostacyclin formation completely.

CONCLUSIONS

Sevoflurane, but not isoflurane, can reduce stimulated endothelial prostacyclin production in a concentration-dependent manner. Because at least 2 MAC of sevoflurane were required, this effect should be of minor importance under clinical conditions of balanced anaesthesia.

Aspirin, but not the more selective cyclooxygenase (COX)-2 inhibitors meloxicam and SC 58125, aggravates postischaemic cardiac dysfunction, independent of COX function

Inhibition of cyclooxygenase (COX) might favour non-enzymatic formation of cardiodepressive isoprostanes from arachidonic acid by radicals generated during reperfusion. This could explain deleterious effects of acetylsalicylic acid (ASA) on cardiac function. We examined the influence of COX inhibition on myocardial function after low-flow ischaemia and reperfusion, employing either ASA (100 micromol/l), the partially selective COX-2 inhibitor meloxicam (0.3 micromol/l and 3.0 micromol/l), or the highly selective COX-2 inhibitor SC 58125 (1.0 micromol/l and 3.0 microgmol/l). Isolated, buffer-perfused guinea pig hearts, performing pressure-volume work before and after consecutive low-flow ischaemia and reperfusion, were used for the study. Measurement of coronary and aortic flow, ejection time and heart rate served to calculate external heart work (EHW), before and after ischaemia. Additionally, release of prostacyclin and thromboxane A2, production of lactate, consumption of pyruvate and tissue concentration of the isoprostane 8-iso-PGF2alpha were measured. ASA significantly reduced recovery of EHW (46+/-18% vs. 82+/-15% for controls), whereas meloxicam and SC 58125 did not (64+/-15% and 74+/-13% recovery, respectively). Paradoxically, ASA increased reactive hyperaemia and consumption of pyruvate in the early reperfusion phase in comparison to all other groups, while lactate production did not differ. Prostacyclin production did not increase during reperfusion and was not significantly different between groups at any time point. In contrast, thromboxane A2 release increased about fivefold in the 2nd min of reperfusion under control conditions and in the presence of SC 58125, but was inhibited by ASA and by meloxicam in both concentrations. Isoprostane content of heart tissue was not detectably influenced under the mild reperfusion conditions used here. We conclude that ASA can aggravate postischaemic cardiac dysfunction, independent of COX inhibition. The deleterious effect in the present model might be due to uncoupling of mitochondrial oxidative phosphorylation rather than to direct effects of reduced eicosanoid release or radical induced formation of isoprostanes.

Nonuniform behavior of intravenous anesthetics on postischemic adhesion of neutrophils in the guinea pig heart

Adhesion of polymorphonuclear neutrophils (PMN) to the coronary endothelium is a crucial step in the development of ischemic myocardial injury. We tested the possible effects of six widely used IV anesthetics on non- and postischemic coronary adhesion of PMN in isolated perfused guinea pig hearts. Hearts (n = 5-11/group) were perfused under conditions of constant coronary flow. After 15 min global warm ischemia, PMN (10(6)) were infused in the second minute of reperfusion. The number of cells reemerging in the coronary effluent within 2 min was expressed as a percentage of the total number of administered PMN. Anesthetics were given 20 min before ischemia and during reperfusion. In addition, the ability of the drugs to influence the oxidative burst reaction of PMN was assessed by measuring luminol-enhanced chemiluminescence in response to 0.1 microM N-formyl-L-methionyl-L-leucyl-L-phenylalanine. Under nonischemic conditions, 26.3% +/- 0.5% of the injected PMN did not acutely reemerge from the coronary system. Subjecting the hearts to ischemia augmented retention to 40.0% +/- 1.6% (P < 0.05). This postischemic stimulation of adhesion was fully prevented by ketamine (10 microM: 22.8% +/- 1.6%, 20 microM: 26.6% +/- 0.7%), thiopental (25 microM: 24.0% +/- 1.7%, 50 microM: 24.0% +/- 1.4%), and midazolam (1.5 microM: 29.0% +/- 0.9%, 3 microM: 26.4% +/- 1.4%). Propofol also inhibited the augmented postischemic retention at 25 microM (28.7% +/- 2.4%). However, 50 microM propofol, etomidate (0.5 and 1 microM), and fentanyl (1 microM) all had no effect. Only thiopental reduced the nonischemic adhesion value (14.0% +/- 3.7%). This may be linked to the direct antioxidative action of thiopental (50% reduction in oxidative burst activity). Whereas ketamine, midazolam, and propofol did not significantly influence oxidant production by PMN, etomidate and the lipid solvent Intralipid enhanced the burst reaction. This activating effect of the lipid component could explain the biphasic behavior of propofol emulsion. Despite some possible differences in efficacy, several IV anesthetics may protect the heart from PMN-mediated reperfusion injury.

IMPLICATIONS

Ketamine, thiopental, and midazolam, but not etomodate or fentanyl, reduce postischemic adhesion of neutrophils in the coronary system of isolated perfused guinea pig hearts, suggesting a role in mitigating myocardial reperfusion injury.

Development of a knowledge-base for automatic monitoring of renal function of intensive care patients over time

Renal dysfunction is a major problem in the management of critically ill patients. Monitoring of renal parameters over time is a prerequisite for detection of any significant deterioration of kidney function. Thus, we developed a knowledge-base for the dynamic monitoring of renal function of critically ill patients. A database with renal parameters of 750 intensive care patients was analyzed for distribution of parameters within predefined intervals of the creatinine clearance. Additionally, a subgroup of 11 patients with (quite) normal renal function over 11 days was selected and the daily variability of renal parameters was analyzed. An interdisciplinary expert team selected a set of nine clinically relevant renal parameters and formulated, on the basis of the data analysis and the parameter set, eight definitions of renal function, which represent four levels of renal performance. These definitions were arranged into an hierarchical structure, considering only clinically relevant changes of renal function. A change from one functional state to another inside of 2 days indicates a relevant alteration of renal function. Monitoring of time courses can additionally be performed by statistical analysis of the daily variability of parameters and comparison with their 'normal' variability. Moreover, rules were established for the plausibility check of results and interpretations of single parameters and parameter sets formulated.

Endothelial function and hemostasis

The vascular endothelium influences not only the three classically interacting components of hemostasis: the vessel, the blood platelets and the clotting and fibrinolytic systems of plasma, but also the natural sequelae: inflammation and tissue repair. Two principal modes of endothelial behaviour may be differentiated, best defined as an anti- and a prothrombotic state. Under physiological conditions endothelium mediates vascular dilatation (formation of NO, PGI2, adenosine, hyperpolarizing factor), prevents platelet adhesion and activation (production of adenosine, NO and PGI2, removal of ADP), blocks thrombin formation (tissue factor pathway inhibitor, activation of protein C via thrombomodulin, activation of antithrombin III) and mitigates fibrin deposition (t- and scuplasminogen activator production). Adhesion and transmigration of inflammatory leukocytes are attenuated, e.g. by NO and IL-10, and oxygen radicals are efficiently scavenged (urate, NO, glutathione, SOD). When the endothelium is physically disrupted or functionally perturbed by postischemic reperfusion, acute and chronic inflammation, atherosclerosis, diabetes and chronic arterial hypertension, then completely opposing actions pertain. This prothrombotic, proinflammatory state is characterised by vaso-constriction, platelet and leukocyte activation and adhesion (externalization, expression and upregulation of von Willebrand factor, platelet activating factor, P-selectin, ICAM-1, IL-8, MCP-1, TNF alpha, etc.), promotion of thrombin formation, coagulation and fibrin deposition at the vascular wall (expression of tissue factor, PAI-1, phosphatidyl serine, etc.) and, in platelet-leukocyte coaggregates, additional inflammatory interactions via attachment of platelet CD40-ligand to endothelial, monocyte and B-cell CD40. Since thrombin formation and inflammatory stimulation set the stage for later tissue repair, complete abolition of such endothelial responses cannot be the goal of clinical interventions aimed at limiting procoagulatory, prothrombotic actions of a dysfunctional vascular endothelium.

Sevoflurane and isoflurane do not enhance the pre- and postischemic eicosanoid production in guinea pig hearts

Eicosanoids and volatile anesthetics can influence cardiac reperfusion injury. Accordingly, we analyzed the effects of sevoflurane and isoflurane applied in clinically relevant concentrations on the myocardial production of prostacyclin and thromboxane A2 (TxA2) and on heart function. Isolated guinea pig hearts, perfused with crystalloid buffer, performed pressure-volume work. Between two working phases, hearts were subjected to 15 min of global ischemia followed by reperfusion. The hearts received no anesthetic, 1 minimum alveolar anesthetic concentration (MAC) isoflurane (1.2 vol%), or 0.5 and 1 MAC sevoflurane (1 vol% and 2 vol%), either only preischemically or pre- and postischemically. In additional groups, cyclooxygenase function was examined by an infusion of 1 microM arachidonic acid (AA) in the absence and presence of sevoflurane. The variables measured included the myocardial production of prostacyclin, TxA2 and lactate, consumption of pyruvate, coronary perfusion pressure, and the tissue level of isoprostane 8-iso-PGF2alpha. External heart work, determined pre- and postischemically, served to assess recovery of heart function. Volatile anesthetics had no impact on postischemic recovery of myocardial function (50%-60% recovery), perfusion pressure, lactate production, or isoprostane content. Release of prostacyclin and TxA2 was increased in the early reperfusion phase 5-8- and 2-4-fold, respectively, indicating enhanced AA liberation. Isoflurane and sevoflurane did not augment the eicosanoid release. Only 2 vol% sevoflurane applied during reperfusion prevented the increased eicosanoid formation in this phase. Infusion of AA increased prostacyclin production approximately 200-fold under all conditions, decreased pyruvate consumption irreversibly, and markedly attenuated postischemic heart work (25% recovery). None of these effects were mitigated by 2 vol% sevoflurane. In conclusion, only sevoflurane at 2 vol% attenuated the increased liberation of AA during reperfusion. Decreased eicosanoid formation had no effect on myocardial recovery in our experimental setting while excess AA was deleterious. Because eicosanoids influence intravascular platelet and leukocyte adhesion and activation, sevoflurane may have effects in reperfused tissues beyond those of isoflurane.

IMPLICATIONS

In an isolated guinea pig heart model, myocardial eicosanoid release was not increased by isoflurane or sevoflurane, either before or after ischemia. Sevoflurane (2 vol%) but not isoflurane attenuated the increased release of eicosanoids during reperfusion.

Ketamine does not inhibit inflammatory responses of cultured human endothelial cells but reduces chemotactic activation of neutrophils

BACKGROUND

Ketamine is a widely used general anaesthetic, which has been reported to inhibit neutrophil function and neutrophil-endothelial interaction. To date, however, it is unknown whether ketamine has any direct effects on endothelial cells with respect to inflammation. Therefore, we investigated the influence of varying concentrations of ketamine (0.5, 1, and 3 microM) on the endothelial expression of cytokines and adhesion molecules with relevance for inflammation.

METHODS

Cultured human umbilical vein endothelial cells were stimulated with tumor necrosis factor alpha (TNFalpha, 2.5 ng/ml) for 4 h in the absence or presence of ketamine. The adhesion molecules ICAM-1 and E-selectin on the endothelial cells were measured by flow cytometry. Release of the proinflammatory cytokines IL-6 and IL-8 by endothelial cells was quantified by ELISA. The acute effect of ketamine on leukocyte activation by the supernatant of endothelial cells pre-stimulated with TNFalpha (4 h) was tested by flow cytometric measurement of CD11b, a leukocyte activation marker, after 15 min of coincubation.

RESULTS

TNFalpha caused dramatic upregulation of both adhesion molecules (15-fold and 5-fold vs. control for ELAM-1 and ICAM-1, respectively) and of both cytokines (500-fold and 1.8-fold for IL-6 and IL-8, respectively). No concentration of ketamine employed in our study had any effect on these inflammatory parameters. However, activation of leukocytes by supernatant of TNFalpha-conditioned endothelial cells (70% increase of CD11b) was attenuated by coincubation of the PMN with 0.5 and 5 microM ketamine (47% and 44% increase, respectively).

CONCLUSION

These data suggest that ketamine exerts its antiinflammatory actions primarily via inhibition of leukocyte reactivity. Indeed, no inhibition of endothelial responses was detectable in our study.

Sevoflurane and isoflurane protect the reperfused guinea pig heart by reducing postischemic adhesion of polymorphonuclear neutrophils

BACKGROUND

Polymorphonuclear neutrophils (PMNs) contribute to reperfusion injury. Because volatile anesthetics can reduce PMN adhesion in the reperfused, nonworking heart, the authors analyzed whether this action of volatile anesthetics affects cardiac performance after ischemia and reperfusion and further clarified the underlying mechanism.

METHODS

Isolated guinea pig hearts perfused with crystalloid buffer and performing pressure-volume work were used. Hearts were subjected to 15 min global ischemia and 20 min reperfusion. In the intervention groups an intracoronary bolus of 3 x 10(6) PMNs was applied in the second min of reperfusion, either in the absence or presence of 0.5 or 1 minimum alveolar concentration sevoflurane or isoflurane. The number of sequestered PMNs was calculated from the difference between coronary input and output (coronary effluent) of PMNs. Performance of external heart work, determined pre- and postischemically, served as criterion for recovery of myocardial function. Additionally, the expression of the integrin CD11b on the cell surface of PMN was measured before and after coronary passage.

RESULTS

Injection of PMN in the reperfusion phase, but not under nonischemic conditions, reduced recovery of external heart work significantly (from 55+/-7% to 19+/-11%). Addition of sevoflurane or isoflurane in concentrations of 0.5 and 1 minimum alveolar concentration to the perfusate reduced postischemic PMN adhesion from 36+/-8% to basal values (20+/-7%) and prevented decline of cardiac function. CD11b expression on PMNs increased significantly during postischemic coronary passage under control conditions. Again, both anesthetics in both concentrations inhibited that activation.

CONCLUSIONS

Volatile anesthetics reduce PMN adhesion in the reperfused coronary system and thereby preserve cardiac function. Reduced expression of the adhesion molecule CD11b on PMNs in the presence of sevoflurane or isoflurane is, at least in part, responsible for the cardioprotective effect.

S(+)-ketamine, but not R(-)-ketamine, reduces postischemic adherence of neutrophils in the coronary system of isolated guinea pig hearts

Polymorphonuclear neutrophils (PMN) play a crucial role in the initiation of reperfusion injury. In a previous study, we found that ketamine reduced the postischemic adherence of PMN to the intact coronary system of isolated guinea pig hearts. Because ketamine is a racemic mixture (1:1) of two optical enantiomers, we looked for possible differences in action between the stereoisomers. Seventy-six guinea pig hearts were perfused in the "Langendorff" mode under conditions of constant flow (5 mL/min) using modified Krebs-Henseleit buffer. After 15 min of global warm ischemia, freshly isolated human PMN (10(6)) were infused as a bolus into the coronary system during the second minute of reperfusion. PMN adhesion was expressed as the numeric difference between PMN recovered in the effluent and those applied. Series A hearts received 5 microM S(+), 5 microM R(-), or 10 microM racemic ketamine starting 20 min before ischemia and during reperfusion. In Series B hearts, 10 microM nitro-L-arginine, an inhibitor of NO synthase, was added to the perfusate. In Series C, PMN were preincubated for 15 min with 5 microM S(+)- or R(-)-ketamine. Coronary vascular leak was assessed by measuring the rate of formation of transudate on the epicardial surface. Ischemia/reperfusion without anesthetics increased coronary PMN adherence from 25.5% +/-2.3% (basal) to 35.3%+/-1.5% of the number applied. S(+)-ketamine reduced postischemic adherence in each series (A, 25.5%+/-5.1%; B, 22.5%+/-1.7%; C, 25.3%+/-7.7%), as did racemate (A, 26.4%+/-3.7%). Although 5 microM R(-)-ketamine had no effect on adhesion (A, 30.5%+/-6.7%; B, 34.3%+/-5.1%; C, 34.3%+/-4.3%), it significantly increased vascular leak in the presence of NOLAG. These findings indicate stereoselective differences in biological action between the two ketamine isomers: S(+)-ketamine inhibited PMN adherence, R(-)-ketamine worsened coronary vascular leak in reperfused isolated hearts.

IMPLICATIONS

In this study, we demonstrated stereoselective differences in the biologic action of the two ketamine isomers in an animal model of myocardial ischemia. Polymorphonuclear neutrophil adherence to the coronary vasculature after ischemia was inhibited by S(+)-ketamine, whereas R(-)-ketamine increased coronary vascular fluid leak.

The volatile anesthetic sevoflurane mitigates cardiodepressive effects of platelets in reperfused hearts

Adherent platelets in the coronary system can impair cardiac pump function. The volatile anesthetics sevoflurane, halothane, and isoflurane have been shown to reduce platelet adhesion. Additionally, an inhibitory effect on platelet cyclo-oxygenase-dependent formation of thromboxane A2 (TxA2) has been proposed for sevoflurane. Therefore, we analyzed the influence of sevoflurane on cardiac performance and TxA2 production after intracoronary application of platelets in isolated guinea pig hearts. Isolated guinea pig hearts perfused with Krebs-Henseleit buffer and performing pressure-volume work were employed. We compromised myocardial function by subjecting hearts to ischemia (20 min low-flow plus 10 min stopped-flow) and reperfusion. During low-flow perfusion the coronary endothelium was stimulated by thrombin prior to and during infusion of a bolus of 10(8) washed human platelets. Intervention groups contained either sevoflurane in a concentration being equivalent to 1 MAC in the platelet suspension or in the perfusate or 1 microM SQ29,548 (an isoprostane- and thromboxane-receptor antagonist) in the perfusate. The parameter external heart work (EHW), determined pre- and postischemically, served as criterion for loss of myocardial function. Additionally, formation of transudate and the production of TxA2 were measured during the reperfusion phase. Coronary perfusion pressure and myocardial production of lactate and consumption of pyruvate were also determined. Adherent platelets significantly enhanced loss of EHW after ischemia and reperfusion, but strongly attenuated coronary vascular leak. Sevoflurane reduced platelet adhesion when applied to the perfusate, but not when given only to the platelet suspension. However, platelets pretreated with sevoflurane lost their cardiodepressive effects, as did platelets in hearts treated with SQ29,548. Surprisingly, TxA2 formation in hearts was not different after platelet application in comparison to the ischemia control group but was significantly reduced when sevoflurane was applied to the perfusate. Neither metabolic parameters, coronary perfusion pressure, vascular leak nor glycoprotein expression of platelets were influenced by sevoflurane.

CONCLUSIONS

1) Pretreatment of hearts with sevoflurane reduces intracoronary platelet adhesion, most likely via an endothelial mechanism. 2) Pretreatment of platelets with sevoflurane does not reduce platelet adhesion, but nevertheless averts cardiodepressive effects derived from or generated by adherent platelets. 3) Transudate formation of hearts during reperfusion was reduced after platelet application, independent of the adherence of platelets.

[Attitude towards physician-assisted suicide among German doctors. A representative survey of the medical district association of Würzburg]

BACKGROUND AND OBJECTIVE

The widespread legalization of "physician assisted suicide" (PAS) in The Netherlands and comparable tendencies in other European countries have given rise to discussions of this topic in Germany. This questionnaire was undertaken because of the dearth of previous informative studies in Germany.

SUBJECTS AND METHODS

Among all registered practicing doctors in the medical district of Würzburg (n = 1821) a randomly selected group of 150 (males and females) was asked to participate in a personal interview-enquiry about active and passive euthanasia. 93 (62%, 32% women, 61% men) agreed: 44.1% were doctors working in a hospital, 45.2% worked in their own practice, the others worked elsewhere or (3) were retired. All specialties and medical activities were represented. About 40% were general practitioners or worked in internal medicine.

RESULTS

81.7% of the group were against active PAS. All rejected it for non-moribund patients.

CONCLUSIONS

The results of this study differ from similar enquiries in other countries in demonstrating a relatively strong rejection of active assistance in patient-suicide. Those German specialists who would most likely be confronted with this problem (e.g. neurologists, intensivists, anaesthetists, oncologists) tended towards a greater readiness to agree to physician-assisted suicide. A dialogue between doctors in different specialties is an urgent requirement and should be intensively pursued.

Volatile anaesthetics reduce adhesion of blood platelets under low-flow conditions in the coronary system of isolated guinea pig hearts

BACKGROUND

Inhibitory effects of volatile anaesthetics on platelet aggregation have been demonstrated in several studies. However, the influence of volatile anaesthetics on intracoronary platelet adhesion has not been elucidated so far.

METHODS

Isolated hearts of guinea pigs were perfused with buffer in the absence or presence of volatile anaesthetics (0.5 and 1 MAC) at constant coronary flow rates of 5 ml/min for 25 min, then 1 ml/min for 30 min and again 5 ml/min for 10 min. Before, during and after low-flow perfusion, a bolus of human platelets was applied into the coronary system. To simulate thrombogenic conditions, 0.3 U/ml human thrombin was infused during low-flow perfusion and reperfusion. The number of platelets sequestered to the endothelium was calculated from the difference between coronary in- and output of platelets. The myocardial production of lactate and consumption of pyruvate and coronary perfusion pressure were also determined.

RESULTS

At a flow rate of 5 ml/min only about 3% of the applied platelets did not emerge from the coronary system, in any group. In contrast, 13.1 +/- 1.2% (mean +/- SEM) of infused platelets became adherent in low-flow perfusion in the control group without anaesthetic. The adherence was reduced with each 1 MAC isoflurane (to 6.2 +/- 1.2%), sevoflurane (to 4.4 +/- 0.9%) or halothane (to 3.2 +/- 1.5%) (each P < 0.05 vs. control). Volatile anaesthetic, 0.5 MAC, did not inhibit platelet adhesion to a statistically significant extent in any case. Perfusion pressure and metabolic parameters were not statistically different between the control and the hearts exposed to anaesthetics.

CONCLUSION

Volatile anaesthetics in a concentration of 1 MAC can reduce the adhesion of platelets in the coronary system under reduced flow conditions. This action does not arise from vasodilation or inhibition of ischaemic stress.