Evolution of the occurrence of Tityus serrulatus (LUTZ & MELLO, 1992) in the state of Santa Catarina

BACKGROUND

Scorpions are a leading cause of envenomation in Brazil. The species Tityus serrulatus is associated with the most severe cases, especially in children. Despite not being endemic to the state of Santa Catarina, such occurrences have increased more than 500% in the state recently. Therefore, this study aimed to analyze the occurrence of envenomation by T. serrulatus, attended by the Center for Toxicological Information and Assistance of Santa Catarina.

METHODS

This was a retrospective and descriptive study of the occurrence of T. serrulatus, identified by the agency, from 2014 to 2021 in Santa Catarina, using data obtained by the BI-DATATOX system.

RESULTS

A total of 112 occurrences were classified as envenomation. Of these cases, 48.2% were recorded in the Itajaí Valley region and 33% in Greater Florianópolis. Men were involved in 59.8% of these, and the most common age group was 20-39 years (39.3%). Most envenomation occurred in urban areas (89.3%) under non-occupational circumstances (83%). Stings were more frequent on the hands (50.9%). Care was sought within 1 h after the event in 75.9% of the cases, and 94.6% were classified as mild.

CONCLUSIONS

Occurrence of envenomation involving T. serrulatus in Santa Catarina increased significantly during the study period. Most cases occurred in urbanized areas, which suggests that they might have been transported from other states, and it must be considered that, in the urban environment, scorpions find a large supply of food and shelter and a reduced number of specific predators, allied to parthenogenesis.

Sympathetic nervous system hyperactivity-induced oxidative stress promoting endothelial dysfunction is dependent on the NADPH oxidases/SGLT2 crosstalk: potential role in cardiogenic shock

Background

Hyperactivity of the sympathetic nervous system (SNS) promotes cardiac dysfunction, that can contribute to heart failure and even cardiogenic shock. Endothelial dysfunction associated with increased formation of reactive oxygen species (ROS) has been suggested to promote cardiac dysfunction and heart failure. Our previous results showed that SGLT2 and ROS derived from endothelial NADPH oxidases contribute to cardiac dysfunction.

Purpose

Therefore, this study examined whether cardiogenic shock and hyperactivation of the SNS involve NADPH oxidases and SGLT2 in the development of endothelial dysfunction using in vitro and in vivo approaches.

Methods

Peripheral blood from patients with cardiogenic shock and healthy controls was drawn by vein puncture into tubes containing sodium citrate. Cultured human microvascular endothelial cells (HMEC-1) were stimulated with either 100 nM of the β-adrenergic agonist isoproterenol or with heparinized (10 U/ml) patient plasma. Male wild-type mice and mice lacking the NADPH oxidase subunit p22phox in the endothelium (p22phox ecKO, 11-week-old) were treated with isoproterenol (100 mg/kg) for five consecutive days and sacrificed at day 14. ROS levels were assessed by dihydroethidium fluorescence, and the expression levels of target genes and proteins by RT-qPCR and Western blot, respectively. siRNA approaches were used to down-regulate the NADPH oxidase subunit p22phox or SGLT2.

Results

Exposure of HMEC-1 to either plasma from patients suffering from cardiogenic shock or isoproterenol stimulated the formation of ROS. ROS levels were reduced by N-acetylcysteine (an antioxidant) and silencing of p22phox, by empagliflozin (a selective SGLT2 inhibitor) and silencing of SGLT2 as well as by metoprolol (a beta1 adrenergic receptor antagonist) and ICI-118,551 (a beta2 adrenergic receptor antagonist). Cardiogenic shock patient plasma and isoproterenol upregulated the NADPH oxidase subunits p22phox and Nox4 as well as SGLT2. These responses were prevented by silencing of either p22phox or SGLT2, and by empagliflozin. In addition to improved cardiac function and blunted SGLT2 expression, p22phox ecKO mice were protected against isoproterenol-induced endothelial dysfunction and senescence, characterized by upregulation of eNOS, nitrotyrosine, VCAM-1 and p16 in the left ventricle.

Conclusion

SNS hyperactivity and cardiogenic shock-derived patient plasma cause a feed forward loop between NADPH oxidases and SGLT2, promoting pro-oxidant responses and endothelial dysfunction via activation of both beta1 and beta2 adrenergic receptors. The NADPH oxidase/SGLT2 crosstalk also contributes to SNS hyperactivity-induced senescence, cardiac and endothelial dysfunction. Thus, the endothelial NADPH oxidases/SGLT2 crosstalk appears to have a major role in cardiac diseases associated with SNS hyperactivity such as cardiogenic shock.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Deutsches Herzzentrum München

A miRNA derived from the 17/92 cluster is a novel player in programming pulmonary hypertension in response to gestational hypoxia via NADPH oxidases and the mTOR pathway

Background

Gestational hypoxia can lead to intrauterine growth restriction (IUGR) and programming of cardiovascular diseases in adulthood via different, although not completely understood, epigenetic mechanisms. We have previously shown that reactive oxygen species (ROS) derived from NADPH oxidases contribute to hypoxia induced pulmonary hypertension (PH). However, their role in disease programming by gestational hypoxia is not resolved.

Purpose

We aimed to elucidate the role of NADPH oxidases and redox sensitive miRNAs in the cardiovascular response of adult offspring to transient gestational hypoxia.

Methods

Wildtype (WT) and nmf333 mice, lacking a functional p22phox dependent NADPH oxidase, were exposed to gestational hypoxia from E10.5 to E11.5. Embryos and adult offspring were analyzed by functional, immunohistochemical and molecular methods including mRNA and miRNA profiling. miRNA mimics or inhibitors were applied in vivo and in vitro using embryoid bodies (EBs). Heart samples from patients with right heart disease associated with congenital heart disease (CHD) were used to validate target miRNA expression.

Results

Transient gestational hypoxia was sufficient to induce IUGR in embryos and pulmonary hypertension (PH) characterized by right ventricular hypertrophy, increased right ventricular pressure and pulmonary vascular remodeling in adult offspring from WT mice while p22phox-deficient nmf333 mice were protected. Cardiac mRNA and miRNA profiling followed by qPCR validation identified several single miRNAs derived from the 17/92 miRNA cluster as downregulated by gestational hypoxia and NADPH oxidases in embryos and adult offspring hearts. In vitro analyses using EBs validated a single miRNA from this cluster to be sufficient to induce cardiac differentiation in response to hypoxia and p22phox, and target analyses identified the mTOR pathway as dysregulated. Treatment with an inhibitor targeting this miRNA was sufficient to induce PH in adult mice, while treating offspring derived from gestational hypoxia pregnancies with an miRNA mimic prevented the development of PH in the adult and dysregulation of the mTOR pathway. Importantly, expression of this single miRNA from the miRNA 17/92 cluster was negatively correlated to right ventricular pressure in CHD patients.

Conclusions

In this study, we demonstrate that gestational hypoxia programs PH in adulthood by upregulating NADPH oxidases and downregulating miRNAs derived from the 17/92 cluster subsequently affecting the mTOR pathway. Since dysregulation of a single miRNA from this cluster induced not only PH but was also associated with right ventricular pressure in CHD patients, these findings might open novel options for diagnosis, prevention and treatment of right heart disease.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): DZHK (German Centre for Cardiovascular Research)

Endothelial NADPH oxidases protect against sympathetic nervous system hyperactivity-induced cardiac dysfunction and remodeling in mice: contribution of SGLT2

Background

NADPH oxidase-derived reactive oxygen species (ROS) contribute to cardiac dysfunction, often characterized by coronary microvascular dysfunction, an inflammatory response and cardiomyocyte hypertrophy. Hyperactivity of the sympathetic nervous system (SNS) induces oxidative stress, promoting cardiac dysfunction and the development of heart failure. Selective inhibitors of sodium-glucose co-transporter 2 (SGLT2), have shown remarkable cardioprotective effects in clinical studies. Recently, SGLT2 inhibitors have been reported to prevent endothelial dysfunction and pro-inflammatory responses in endothelial cells in response to angiotensin II involving NADPH oxidases.

Purpose

Therefore, the aim of the study was to determine whether endothelial NADPH oxidases promote SNS-induced cardiac dysfunction and to clarify the role of SGLT2.

Methods

Male wild-type mice and mice lacking the NADPH oxidase subunit p22phox in the endothelium (p22phox ecKO, 11-week-old) were treated with isoproterenol (100 mg/kg) for five consecutive days and sacrificed at day 14. Hemodynamic measurements of left (LV) and right (RV) ventricles were performed by a transthoracic approach. Heart tissue sections were stained with Sirius red to evaluate fibrosis and wheat germ agglutinin to assess cardiomyocyte size. Cultured human microvascular endothelial cells (HMEC-1) were stimulated with 100 nM isoproterenol and ROS levels were assessed by dihydroethidium fluorescence. The expression level of target genes and proteins was assessed by quantitative real-time PCR and Western blot, respectively. siRNA approaches were used to down-regulate either the NADPH oxidase subunit p22phox or SGLT2.

Results

The isoproterenol treatment increased LV and RV systolic pressures in wild-type mice but not in p22phox ecKO mice. p22phox ecKO mice were protected against isoproterenol-induced fibrosis, cardiac remodeling characterized by upregulation of mRNA levels of ANP, BNP and β-MHC, and pulmonary congestion. LV remodeling was associated with upregulation of the NADPH oxidase subunits p22phox, Nox2, and Nox4 as well as of SGLT2 in wild-type mice, however no such effects were observed in p22phox ecKO mice. Exposure of HMEC-1 to isoproterenol stimulated the formation of ROS and caused an upregulation of p22phox and SGLT2 protein levels in a time- and concentration-dependent manner. No such effects were observed following silencing of either p22phox or SGLT2, or use of a selective SGLT2 inhibitor.

Conclusion

Deletion of the NADPH oxidase subunit p22phox in the endothelium protected against SNS hyperactivity induced LV cardiac dysfunction and remodeling, and prevented upregulation of SGLT2. Since depletion of SGLT2 prevented the pro-oxidant response to isoproterenol in endothelial cells, the endothelial NADPH oxidase/SGLT2 pathway seems to have a prominent role in promoting cardiac remodeling and dysfunction in SNS hyperactivity.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Deutsches Herzzentrum München

Technical note: Assessment of an alternative technique for measuring body temperature in pigs

Core body temperature (CBT) is one of the main vital signs that is used to evaluate the health status of pigs. The most common and feasible method for assessing CBT in pigs is rectal temperature (RT). Obtaining RT is stressful for animals, may generate inaccurate results, and has the risk of spreading disease. Infrared imaging (IR) thermography of the body of pigs may be a safer and less stressful alternative to RT. The objective of the current study was to evaluate the efficacy of using IR as an alternative for monitoring CBT in pigs. Twenty-three gilts (30.5 ± 5.62 kg BW) were housed in metabolism crates in an environmentally controlled facility and fed an 860 g/d grower diet. After 4 d of adaptation, the febrile response was induced by intramuscular injection of lipopolysaccharide (LPS; 25 µg/kg BW). Each pig's body temperature was recorded at 0, 2, 4, 6, 8, 10, and 24 h after LPS challenge using the following 3 methods: 1) RT, 2) IR of the eye and ear, and 3) CBT using an orally administered digital temperature sensor. Statistical analysis was performed in a completely randomized design in SAS using Mixed, Correlation, and Regression procedures. Relative to time 0 h, LPS increased the eye temperature, CBT, and RT by 0.92, 1.32, and 1.48°C, respectively ( < 0.01), but had no significant effect on ear temperature. Eye temperature, RT, and CBT, but not ear temperature, were highly correlated ( ≥ 0.96) during the course of the study ( < 0.01). Estimated regression parameters (α and β) for predicting CBT using eye temperature were -28.2 ± 8.70 and 1.76 ± 0.221, respectively, and for RT were -24.5 ± 7.69 and 1.65 ± 0.196, respectively ( ≥ 0.96; 95% confidence interval). Collectively, these results indicated a strong relationship between eye temperature, RT, and CBT in pigs. Therefore, IR of the eye can be used as a precise, noncontact alternative to RT measurements for monitoring CBT in swine.

Analysis of Immunological, Viral, Genetic, and Environmental Factors That Might Be Associated with Decreased Susceptibility to HIV Infection in Serodiscordant Couples in Florianópolis, Southern Brazil

Individuals who have been exposed to human immunodeficiency virus (HIV) and have not been infected might possess natural resistance mechanisms. An understanding of the sociodemographic and immunological conditions that influence resistance to HIV is a challenge, and very little is known about the role of intrinsic antiviral factors that restrict HIV infection. The aim of this study was to analyze potential factors responsible for resistance to HIV infection in serodiscordant couples by comparing HIV-exposed seronegative individuals (HESN) to HIV-seropositive individuals treated with antiretroviral therapy (HIV-ART) along with healthy controls (HC). The results revealed one HLA-B*27 and two HLA-B*57 individuals among the HESN; a CCR5Δ32 heterozygous deletion was observed in one serodiscordant couple, while the homozygous genotype for this variant was not observed. There were no differences in the basal mRNA expression of APOBEC3G, CFLAR, TRIM5α, LEDGF/p75, BST-2, or SAMHD1 in CD4(+) T lymphocyte- and monocyte-enriched populations among the three groups, and lower HBD-3 concentrations were observed in saliva from HIV-ART compared to HESN and HC. The most prevalent HIV-1 subtype was C or C-containing recombinant forms. Six HIV-ART individuals and one HIV-ART individual were infected with the R5 HIV and X4 HIV strains, respectively. The ability to control infection or delay disease progression is probably defined by a balance between viral and host factors, and further evaluation should be performed in larger cohorts. Our data suggest that susceptibility to HIV infection varies among individuals and strengthens the multifactorial characteristics underlying the resistance mechanisms in HIV.

HIV infection and antiretroviral therapy lead to unfolded protein response activation

Background

The unfolded protein response (UPR) is one of the pathways triggered to ensure quality control of the proteins assembled in the endoplasmic reticulum (ER) when cell homeostasis is compromised. This mechanism is primarily composed of three transmembrane proteins serving as stress sensors: PKR-like ER kinase (PERK), activating transcription factor 6 (ATF6), and inositol-requiring enzyme 1 (IRE1). These three proteins’ synergic action elicits translation and transcriptional downstream pathways, leading to less protein production and activating genes that encode important proteins in folding processes, including chaperones. Previous reports showed that viruses have evolved mechanisms to curtail or customize this UPR signaling for their own benefit. However, HIV infection’s effect on the UPR has scarcely been investigated.

Methods

This work investigated UPR modulation by HIV infection by assessing UPR-related protein expression under in vitro and in vivo conditions via Western blotting. Antiretroviral (ARV) drugs’ influence on this stress response was also considered.

Results

In in vitro and in vivo analyses, our results confirm that HIV infection activates stress-response components and that ARV therapy contributes to changes in the UPR’s activation profile.

Conclusions

This is the first report showing UPR-related protein expression in HIV target cells derived directly from HIV-infected patients receiving different ARV therapies. Thus, two mechanisms may occur simultaneously: interference by HIV itself and the ARV drugs’ pharmacological effects as UPR activators. New evidence of how HIV modulates the UPR to enhance its own replication and secure infection success is also presented.

Electronic supplementary material

The online version of this article (doi:10.1186/s12985-015-0298-0) contains supplementary material, which is available to authorized users.

Changes in the prevalence, incidence and residual risk for HIV and hepatitis C virus in Southern Brazilian blood donors since the implementation of NAT screening

INTRODUCTION

Previous studies have shown high residual risk of transfusing a blood donation contaminated by human immunodeficiency virus (HIV) or hepatitis C virus (HCV) in Brazil and motivated the development of a Brazilian platform for simultaneous detection of both viruses by nucleic acid amplification test (NAT) denominated HIV/HCV Bio-Manguinhos/Fundação Oswaldo Cruz (FIOCRUZ). The objective of this study was to verify seroprevalence, incidence and residual risk for both viruses before and after the implementation of NAT.

METHODS

Over 700,000 blood samples from all blood banks in the southern Brazilian State of Santa Catarina were analyzed during the period between January 2007 and July 2013.

RESULTS

Compared with the period preceding the NAT screening, HIV prevalence increased from 1.38 to 1.58 per 1,000 donors, HIV incidence rate increased from 1.22 to 1.35 per 1,000 donor-years, and HIV residual risk dropped almost 2.5 times during the NAT period. For HCV, seroprevalence increased from 1.22 to 1.35 per 1,000 donors, incidence dropped from 0.12 to 0.06 per 1,000 donor-years, and residual risk decreased more than 3 times after the NAT implementation.

CONCLUSIONS

NAT reduced the duration of the immunologic window for HIV and HCV, thus corresponding to approximately 2.5- and 3-fold respective residual risk reductions.

Syphilis seroprevalence estimates of Santa Catarina blood donors in 2010

INTRODUCTION

Knowledge of blood donor characteristics is essential to better guide clinical and serological screening for hemotherapy. The objective of this study was to determine the syphilis seroprevalence and the associated factors of blood donors in the State of Santa Catarina, Brazil.

METHODS

This population-based study from the State of Santa Catarina used information obtained from blood donation records. We analyzed 83,396 blood donor records generated from donors who were considered eligible to donate between January and August 2010. The aim of the study was to estimate the syphilis seroprevalence and its relationship with educational level, age, gender, geographical region and having donated blood in the past 12 months. We used descriptive analyses and a Poisson regression to calculate the prevalence ratios for the variables of interest.

RESULTS

We found a 0.14% overall seroprevalence and significant differences among the following: first-time blood donors (0.19%) versus repeat donors (0.03% to 0.08%); low educational levels (0.30%) versus medium and high educational levels (0.08% to 0.19%); and donors who did not report their residence (0.88%) or age (6.94%) versus those who did. Increased syphilis seroprevalence was also significantly associated with increased age.

CONCLUSION

High syphilis seroprevalence was associated with lower educational level, age, first-time donation and the failure to provide age or residence information.

Case report of a haemovigilance investigation using phylogenetic analysis of HIV-1 in Brazil

OBJECTIVES

The aim of this work is to provide the first report of a transfusion-acquired HIV-1 infection and to verify transmission from the donor to the recipients using phylogenetic analysis of HIV-1 DNA sequences in a Brazilian blood bank.

BACKGROUND

Although haemovigilance procedures based on phylogenetic analysis of HIV have been reported in several countries, this type of study has yet to be conducted in Latin America.

MATERIALS AND METHODS

Upon identifying a HIV-1-positive repeat blood donor by enzyme immunoassay (EIA) blood screening, all recipients of the donor's previous donation were identified and tested for HIV-1 by EIA, nucleic acid amplification test and HIV-1 DNA sequencing and phylogenetic analysis.

RESULTS

One of the recipients tested positive for HIV-1. The phylogenetic analysis showed a high genetic similarity among the viruses, thus supporting the hypothesis of transmission from the donor to the recipient.

CONCLUSIONS

Phylogenetic analysis of HIV-1 DNA sequences has been a decisive tool in verifying suspected transmission of the virus from blood donor to recipient in Brazil.

Comparison of epidemiological methods for estimation of hepatitis B incidence and residual risk for blood donors in southern Brazil

Background and Objective. The objective of this work was to compare three methods for estimating hepatitis B virus (HBV) incidence and residual risk. Methods. Computerized blood donor records in southern Brazil were examined for the period 2004–2006. The methods for estimating HBV incidence included stand-alone HBsAg, HBsAg yield method, and an extension of the latter which added recent anti-HBc seroconversions as incident HBV cases. Results. HBV incidences for the above methods were 9.91, 20.09, and 22.93 per 100000 repeat donors, respectively. In the same order, corresponding residual risks were 1 : 62482, 1 : 30821, and 1 : 47559, respectively. First-time donors had 52 higher HBV incidence compared to repeat donors. Conclusion. Although the three methods compared produced overlapping 95% confidence intervals, their variation was considerably lower for the method which included recent anti-HBc seroconversions. First-time donors are primary cause for concern regarding HBV transmission via blood transfusion in southern Brazil.

Effectiveness of DNA-recombinant anti-hepatitis B vaccines in blood donors: a cohort study

Background

Although various studies have demonstrated efficacy of DNA-recombinant anti-hepatitis B vaccines, their effectiveness in health care settings has not been researched adequately. This gap is particularly visible for blood donors, a group of significant importance in the reduction of transfusion-transmitted hepatitis B.

Methods

This is a double cohort study of 1411 repeat blood donors during the period 1998–2002, involving a vaccinated and an unvaccinated cohort, with matching of the two in terms of sex, age and residence. Average follow-up was 3.17 person-years. The outcome measure was infection with hepatitis B virus (HBV), defined by testing positive on serologic markers HBsAg or anti-HBC. All blood donors were from the blood bank in Joaçaba, federal state of Santa Catarina, Brazil.

Results

The cohorts did not differ significantly regarding sex, age and marital status but the vaccinated cohort had higher mean number of blood donations and higher proportion of those residing in the county capital Joaçaba. Hepatitis B incidences per 1000 person-years were zero among vaccinated and 2,33 among non-vaccinated, resulting in 100% vaccine effectiveness with 95% confidence interval from 30,1% to 100%. The number of vaccinated persons necessary to avoid one HBV infection in blood donors was estimated at 429 with 95% confidence interval from 217 to 21422.

Conclusion

The results showed very high effectiveness of DNA-recombinant anti-HBV vaccines in blood donors. Its considerable variation in this study is likely due to the limited follow-up and the influence of confounding factors normally balanced out in efficacy clinical trials.

[Effectiveness of recombinant DNA vaccines against hepatitis B in blood donors in an endemic region of South Brazil]

The objective of this work was to estimate the effectiveness of DNA recombinant anti-HBV vaccines in a retrospective cohort study of 1,012 Brazilian blood donors who completed the vaccination schedule (3 doses + booster of antibody titer < 10IU/L) during the period 1998-2002. The results showed that seroconversion rates were significantly lower among the donors whose antibody titers was measured six months after completing the vaccination scheme and among older donors, particularly those aged over 50. Overall vaccine effectiveness was 88.7%, ranging from 80.6% in the oldest (50 years or over) to 91.4% among the youngest (18-30 years) donors. The booster regimen was effective at reducing the percentage of non-responders. We conclude that vaccine effectiveness was significantly better in younger blood donors and that the anti-HBs testing interval influenced the vaccine effectiveness.

The use of a bronchial blocker compared with a double-lumen tube for single-lung ventilation during minimally invasive direct coronary artery bypass surgery

OBJECTIVE

To investigate whether a bronchial blocker (BB) placed through a routinely used single-lumen tube (SLT) to achieve 1-lung ventilation is appropriate in patients undergoing a minimally invasive direct coronary artery bypass (MIDCAB) operation.

DESIGN

Clinical trial.

SETTING

University hospital.

PARTICIPANTS

Patients scheduled for elective MIDCAB operation (n = 159).

INTERVENTIONS

Group A was treated with a left-sided double-lumen tube (DLT) and served as the control group. Group B was intubated with a routinely used SLT in combination with a BB.

MEASUREMENTS AND MAIN RESULTS

The following data were collected: (1) time required for placement of each tube, (2) ventilation pressures, (3) lung compliance, (4) dislocations of the DLT or BB, (5) effectiveness of lung collapse, and (6) PaO(2) and fraction of inspired oxygen. In 4 patients (4%) of group B, the BB could not be placed within an acceptable time so that 155 patients (50 patients in group A, 105 patients in group B) were statistically analyzed. Statistically significant differences during 1-lung ventilation were found for peak and mean inspiratory pressure (p < 0.001 and p < 0.05), dynamic and static lung compliance (p < 0.05), and dynamic lung compliance change (p < 0.01). No statistical significance was found for intubation time (p > 0.05) and PaO(2) and fraction of inspired oxygen (p > 0.05). Lung collapse was insufficient in 1 patient of group A (2%) and in 2 patients of group B (2%).

CONCLUSION

To achieve 1-lung ventilation during a MIDCAB procedure, the use of a BB combined with an SLT is an appropriate technique as an alternative to the commonly used DLT.

Dose-response relationship of propofol on mid-latency auditory evoked potentials (MLAEP) in cardiac surgery

BACKGROUND

Propofol-sufentanil anaesthesia has become popular during cardiac surgery for its titrability and short recovery time. Avoidance of awareness is a major goal during cardiac surgery. We therefore investigated the dose-response relationship of propofol and cortical responses (mid-latency auditory evoked potentials, MLAEP).

METHODS

One hundred patients undergoing cardiac surgery were investigated. Basic anaesthesia was performed with sufentanil (4.5 microg kg(-1) h(-1)) / flunitrazepam (9 microg kg(-1) h(-1)) infusion (control group); the other groups received in addition a loading dose of propofol 2 mg kg(-1) and a maintainance infusion of 1-3.5 mg kg(-1) h(-1). MLAEP were evaluated by using Pa/Nb-amplitudes and Nb-latencies. Haemodynamics were monitored by ECG, arterial blood pressure and cardiac function with pulmonary artery catheterization.

RESULTS

In the control group, median amplitude of MLAEP decreased by 50% with a wide range, but were detectable in >90% of patients throughout surgery. Propofol suppressed amplitude Pa/Nb of MLAEP dose dependently. With 3.5 mg kg(-1) h(-1) amplitudes disappeared in >40% of patients throughout cardiac surgery. Median Nb-latencies increased in the control group from 44 to a range from 50 to 60 ms. In groups with propofol >2 mg kg(-1) h(-1), Nb-latencies, detectable in the patients without complete suppression of MLAEP, increased to median 60 ms. Haemodynamic parameters and cardiac function did not differ among the groups. The use of vasopressors was not increased even with the highest propofol dose used.

CONCLUSION

The dose-response effect of propofol on auditory evoked potentials reveals that combining a loading dose of 2 mg kg-1 with a consecutive infusion of 3.5 mg kg(-1) h(-1) significantly suppresses MLAEP during cardiac surgery. Thus, auditory information may not be processed and awareness with recall becomes unlikely.

[Robotic surgery--surgical and anesthesiologic implications]

Because of the restricted freedom of movement inherent in endoscopic standard instruments wholly endoscopic heart surgery has not been possible up to now. The development of such techniques was especially hindered by the rib cage. Now the precision which is imperative for bypass surgery or valve reconstruction is made possible by telemanipulator systems. Preconditions for this method are cardiopulmonary bypass-techniques which allow a cardioplegic cardiac arrest with closed chest and extensive hemodynamic monitoring which enables the anesthesiologist to make exact diagnoses without having a direct view on the heart. After an extensive experimental phase a telemanipulation system is successfully in use since May 1998 in the Cardiac Center in Leipzig.

Computer aided monitor-data processing (CAMP). A landmark for unbiased gauging of anaesthetic courses?

A computer aided monitor-data processing system (CAMP-System) was developed in order to get a consistent and comprehensive database which can very precisely reflect intra-operative haemodynamic courses. The goal of the present study was to introduce a new method to scan and to gauge haemodynamic courses and to demonstrate its superiority over the traditional way of data processing based on a handwritten anaesthesia protocol.

METHODS

The computerized system was applied to a study which was designed to investigate the influence of ketanserin (K) vs. urapidil (U) on haemodynamic stability during cardiac operations. Twenty male patients scheduled for myocardial revascularization received either 20 mg K or 30 mg U. Heart rate, central venous, arterial and pulmonary artery pressures were measured and on-line recorded every 20 seconds by the computer record system. In the handwritten protocol these variables were registered at eight pre-defined time points. Computerized data processing (including artifact depletion and data condensation) was compared to the results evaluated from the handwritten protocol.

RESULTS

While the only significant differences in the handwritten protocol were slightly higher values of pulmonary artery pressures in group K, the computer analysis revealed a number of further differences. Higher maximum and a less stable time course of HR in group K in the pre-bypass phase and lower mean and standard deviation of MAP during cardiopulmonary bypass.

CONCLUSION

Computerized data processing including automatic artifact suppression and data condensation was able to reveal differences in the course of haemodynamic variables that cannot be detected in a conventional handwritten protocol.

Intraoperative monitoring with somatosensory evoked potentials in carotid artery surgery--less reliable in patients with preoperative neurologic deficiency?

BACKGROUND

In a retrospective analysis of intraoperative somatosensory evoked potential (SEP) results during carotid artery surgery we found some cases with postoperative neurologic deficits, surprisingly without significant SEP changes.

METHODS

Median nerve SEP were monitored as usual. Indication for selective shunting was a complete loss of amplitude N20/P25 in the first period of the investigation, later on a 50% reduction, or a prolongation of the central conduction time (CCT) of about 1.5 ms after cross-clamping. Anaesthesia was maintained with isoflurane in N2O/O2, fentanyl and atracurium.

RESULTS

Over a 3-year period 146 patients were monitored. Indications were: transient ischaemic attacks (TIA) (n=51), stroke (n=23), stroke with residuals (n=39), asymptomatical stenosis (n=29), subclavian steal syndrome (n=4). Twenty-four patients received an intraluminal shunt following SEP alterations. Postoperatively, 5 patients (3.4%) had symptoms of intraoperative brain ischaemia (stroke n=2, TIA n=3), 4 of them showing only minor intraoperative SEP alterations; 1 received a shunt because of CCT prolongation. Four of these 5 patients had cerebral neurologic deficiency preoperatively.

CONCLUSION

Since some authors have found a 100% sensitivity of intraoperative SEP, it is remarkable, that 1 patient with postoperative stroke and 3 patients with TIA had no significant SEP changes intraoperatively. We suppose there was an association with preoperative neurological deficits resulting from previous strokes. In such cases, regional critical ischaemia may apparently occur outside the sensory pathway monitored with SEP.

Effects of enoximone on right-ventricular function in patients with impaired myocardial performance

The effects of an enoximone monotherapy on left-ventricular and especially on right-ventricular haemodynamics were investigated in fourteen patients with impaired left-ventricular function secondary to coronary artery disease. Anaesthesia was induced and maintained with fentanyl and flunitrazepam. After reaching steady state, a bolus of 0.5 mg/kg enoximone was administered, followed by an infusion of 0.5 microgram/kg/min. Besides the common haemodynamic parameters particulary the right-ventricular ejection fraction (RVEF) was measured using a special thermodilution technique. The predefined time points were: before administration of enoximone (baseline) and 5 min, 10 min, 15 min, 20 min, and 30 min after bolus injection of enoximone. Compared to the baseline the maximum effects of enoximone were a 28% increase of cardiac index accompanied by a 39% decline of systemic vascular resistance and an unchanged left-ventricular stroke-work index. While central venous pressure and mean pulmonary artery pressure remained unchanged. RVEF (+20%) and right-ventricular stroke-work index (+30%) were significantly augmented, augmented, indicating improved right-ventricular performance. No adverse effects of the enoximone administration were observed perioperatively. We conclude that an enoximone monotherapy is beneficial for patients with impaired myocardial function undergoing cardiac surgery.

[Online recording of monitor data. The artifact problem]

Increasing numbers of monitors at the anaesthesiologist's workplace, providing more than 20 different parameters of the patient's condition, have already made it impossible to record all the values in a handwritten form. Consequently, this most common method of record-keeping must be incomplete and inaccurate. In recent years computerised data-acquisition systems have been introduced into clinical practice in order to produce more reliable records. But after a 7-year experience in the use of such a system in cardiac anaesthesia, we have recognised certain problems that remain to be solved before automated record-keeping will achieve wider acceptance. The first is the handling problem, which was discussed in a previous paper. The second major problem is the appearance of artifacts, caused mainly by mechanical manipulations during the operation. In this paper, 300 courses of anaesthesia that were recorded online during different cardiac surgery procedures were examined and the incidence as well as the kind of artifacts occurring were evaluated. Algorithms were developed for each haemodynamic parameter to suppress these artifacts automatically by a subsequent analysing process; the efficiency of that "artifact filter" was validated in 35 of the 300 cases. Based on more than 30,000 values for each parameter, the incidence of artifacts was 3%-7%. However, only 0.1%-0.5% of the artifacts could not be eliminated by the filter. The method described here provided acceptable graphic printouts of the most important haemodynamic parameters (Figs. 1b and 2b) and would also be suitable to serve as an input filter for automatically running anaesthesia data-examination processes, which are currently being developed in our clinic.

The influence of ketanserin or urapidil on haemodynamics, stress response and kidney function during operations for myocardial revascularisation

The study was performed to investigate the different effects of ketanserin and urapidil on haemodynamics, kidney function and plasma catecholamine and aldosterone levels. Forty male patients scheduled for myocardial revascularisation were assigned at random to two groups: group K received ketanserin, group U received urapidil. Anaesthesia consisted of fentanyl, flunitrazepam and pancuronium. Haemodynamic variables were evaluated at eight predefined time points of the operation. Creatinine and free-water clearance as well as plasma levels of adrenaline, noradrenaline and aldosterone were measured in three different periods of the operation. While the groups showed no clinically relevant differences in the haemodynamic variables and the hormone plasma concentrations, the creatinine clearance in group K was slightly increased in the period after cardiopulmonary bypass. Both ketanserin and urapidil prevented hypertension even in the presence of elevated catecholamine plasma levels during and after cardiopulmonary bypass.

Bicaval versus atrial anastomoses in cardiac transplantation. Right atrial dimension and tricuspid valve function at rest and during exercise up to thirty-six months after transplantation

Conventional cardiac transplantation with atrial anastomoses alters atrial integrity, geometry, and possibly function. Theoretically, this may also contribute to the development of tricuspid insufficiency that is frequently observed after the operation. Thus more anatomic transplantation techniques using bicaval anastomoses were recently introduced into clinical practice. Knowledge of their efficacy, however, is scarce. Therefore right atrial size and tricuspid valve function were compared in patients with bicaval (group A) and standard atrial (group B) anastomoses in a randomized, prospective study. The results of this echocardiographic study at rest and exercise in 18 patients (bicaval n = 8; atrial n = 10) on the average 28 months after transplantation are presented. The right atrial dimension was comparable between group A patients and control subjects and larger in group B patients (p < 0.05). The incidence of tricuspid regurgitation was not different between the two groups at rest, but it was at exercise (50 watts of workload) (p < 0.05). This study suggests that up to 36 months after cardiac transplantation the technique of bicaval in contrast to atrial anastomoses preserves right atrial size and reduces tricuspid regurgitation during exercise. Whether this leads to improved hemodynamics and increased exercise capacity remains to be evaluated in a larger series of patients.

Effects of amrinone on left and right ventricular function in patients with impaired myocardial performance during general anaesthesia

We have studied the effects of amrinone on left and right ventricular haemodynamics in patients with impaired ventricular performance caused by coronary artery disease. Anaesthesia was achieved with fentanyl, flunitrazepam and pancuronium. After reaching steady state, a bolus dose of amrinone 0.5 mg kg-1 was administered followed by an infusion of 1 mg kg-1 h-1. Right ventricular ejection fraction (RVEF) and other haemodynamic variables were evaluated at six times: before, 5, 10, 15, 20 and 30 min after bolus administration of amrinone. Amrinone led to a 23% increase in cardiac index resulting mainly from reduction in afterload. While central venous pressure and mean pulmonary artery pressure remained unchanged, RVEF increased by 28%. This effect may be interpreted as an improvement in right ventricular performance.

[Computer-aided anesthesia monitoring. Experiences with the use of three systems in heart surgery]

Basic monitoring in cardiac anaesthesia embraces at least 19 different parameters of haemodynamics and blood gas analysis. In special cases additional measurements may be desirable, providing a total of up to 44 variables displayed on various monitors, as depicted in Fig. 2. The recording of such an amount of data is only feasible with automated recording systems. Therefore, in the past 6 years we have introduced three different computer systems to our cardiac anaesthesia workplaces. The experiences in their handling are reported. MATERIAL AND METHOD. Three systems were investigated: (1) System S 4000 (Siemens, Germany), based on a central processor unit (PDP 11, DEC, Japan) connected with 20 bedside input/output terminals and Sirecust 404a monitors (Siemens). The system collected the data in a ring buffer with a capacity for about 24-48 h. (2) Patient Care Manager (PCM; Siemens, Germany), a single workplace system based on an IBM-compatible personal computer (PC) with the operating system environment DOS 5.0/Windows 3.0. In our test configuration it was connected with a Sirecust 1281 monitor (Siemens). (3) Monitor-Data-Manager (MDM) (our own development). This single workplace system is also based on an IBM-compatible PC running under DOS and was connected to four different monitors used in our cardiac surgery operating theatre (Fig. 2). A second computer (Sirecust S 425, Siemens) served as an interface between the two 404 monitors (not featuring a serial output like RS 232) and the PC. The self-developed program for that interface was memory resistant and executable with three key presses when the anaesthetic record was started. The three systems were compared with regard to their ease of use, function and practicability. RESULTS. System S 4000: Because of the older system architecture, the response time to key inputs was fairly long and the menu structure somewhat uncomfortable. A major drawback was the limited data buffer capacity and the lack of a long-term storage medium as well as the lack of compatibility with the industry standard for PCs. Software interfaces to other companies' monitors were not implemented, limiting the system to the Sirecust 404 devices. Patient-Care-Manager: The user interface is a Windows 3.0 application representing an up-to-date graphical environment. Unfortunately some Windows features were not fully used, e.g. the free positioning and sizing of graphic windows and the color options. Drug inputs were somewhat long-winded, limiting the system's suitability for the operating theatre. The main disadvantage, however, was the lack of interfaces to monitors other than those from Siemens. Monitor Data Manager: The system was designed to sample data from all monitors operating in our hospital's heart surgery department. Each parameter was displayed in a digital form to get close control over the recorded data (Fig. 1b); additionally calculated values like total peripheral resistance or oxygen demand could be drawn from a separate window. Furthermore, key inputs were reduced to minimum, making drug inputs faster than the hand-written protocol. The ease of performing calculations of continuous drug infusions (from microgram/kg/min to ml/h pump speed) was particularly appreciated by the users. Since the data were saved as an ASCII file, they could easily be imported by any spreadsheet like Lotus 1-2-3 or Excel, providing the whole variety of their graphical presentation or calculation features. Because of the high sampling rate (3 min), even short-lasting drug effects could be registered, making the system favourable for scientific studies. CONCLUSION. Automated monitor data record systems are considered to be a prerequisite not only for research in anaesthesia but also for quality assurance. A basic requirement for wide acceptance in clinical practice is a user interface that provides fast and convenient key inputs as well as further information about parameters not displayed on other monitors. In our h

[The potential dependence of the effect of bupivacaine and ropivacaine on the heart. In-vitro studies on the effect of local anesthetics on the force of contraction and the action potential in left guinea pig atria]

The cardiotoxicity of long acting local anaesthetics is still a matter of controversy. Therefore, the effects of bupivacaine and ropivacaine on cardiac contractility and electrophysiologic parameters were evaluated in the presence of different extracellular potassium concentrations. METHODS. In strips from left atria of guinea pigs action potentials were induced to obtain cumulative dose response curves for bupivacaine (racemic mixture) and ropivacaine (S-enantiomer). Effects on force of contraction and parameters of the action potential (especially maximum upstroke velocity, dV/dtmax, as an indirect measure of fast sodium channel function) were compared for low (2.7 mM) and high (8.7 mM) extracellular K+ concentrations (n = 7-8). RESULTS. At low K+ concentration, bupivacaine and ropivacaine depressed force of contraction and dV/dtmax in a dose-dependent manner. At higher local anaesthetic concentrations, action potential amplitude decreased and action potential duration was prolonged. There was no influence on the resting membrane potential (Tables 2, 3). At high K+ concentration, both local anaesthetics induced effects similar to those observed with low K+, but the dose-response curves for contractility and dV/dtmax were shifted leftward. The EC50 of bupivacaine for the negative inotropic effect and, analogously, for dV/dtmax was approximately 10 times lower. Similar results were observed for ropivacaine (Figs. 1, 2). CONCLUSION. This study confirms the dependence of the cardiodepressive effects of bupivacaine on the extracellular K+ concentration (i.e. membrane potential). The present investigation shows a similar dependence for the effects of ropivacaine, a new long-lasting local anaesthetic. Our results concerning the potential dependency of dV/dtmax depression are compatible with the binding of bupivacaine to the inactivated state of the sodium channel protein preferentially (modulated receptor hypothesis). Thus accumulation of block will occur if stimulation frequency is in an appropriate range. Though we found striking analogies between potential dependency of dV/dtmax depression and negative inotropic effect, there is no firm evidence that the sodium channel block by bupivacaine or ropivacaine substantially participates in the latter effect. An influence on other ionic channels such as the calcium channel remains to be evaluated.

[The neuropathy of the autonomic nervous system. An additional anesthetic risk in diabetes mellitus]

Some 20-40% of diabetics suffer from an autonomic neuropathy. This complication of diabetes mellitus impairs the regulation and the reflexes of the cardiovascular system. This study compares the cardiovascular characteristics of diabetics and nondiabetic control patients. METHODS. 21 patients (11 diabetics, 10 nondiabetics) undergoing ophthalmic surgery were investigated. They were tested preoperatively for autonomic cardiovascular dysfunction by application of four established tests. These were: heart rate responses to the Valsalva maneuver, deep breathing and standing up (30/15 test) and the Schellong test. The anaesthesia was induced with fentanyl (0.1 mg), etomidate (2.5 mg/kg) and succinyl choline (1.5 mg) and maintained with oxygen/nitrous oxide (1.4:3 l/min) and isoflurane (0.2-0.8 vol%). Blood pressure and heart rate were automatically measured every minute during induction of anaesthesia and every 3 min during anaesthesia. Additionally the heart rate response to 0.5 mg atropine i.v. was evaluated. RESULTS. The autonomic function tests revealed pathologic reactions in all diabetics (two early, six definitive, three severe) and none in controls. Remarkable cardiovascular events occurred exclusively in the diabetic group, especially during induction of anaesthesia. The systolic blood pressure (SAP) increased in diabetics from a preinduction value of 150 mmHg (median, range 105-205 mmHg) to a maximum of 200 mmHg (160-250 mmHg) after intubation, in controls from 130 (100-150 mmHg) to 170 (110-190 mmHg). Following this peak, SAP fell in diabetics to 120 mmHg (80-160 mmHg), in controls to 110 (100-140 mmHg). Two diabetics had to be treated because of an SAP exceeding 220 mmHg, two other diabetics because of an SAP below 80 mmHg. After atropine administration the heart rate of diabetics showed a median increase of 15% (range 0-40%). In four diabetics, however, the increase was less than 10%. In control patients the increase was 50% (40-80%). All patients with severe cardiovascular reactions during induction of anaesthesia and with heart rate elevation following atropine of less than 10% had a definite or severe neuropathy of the autonomic nervous system revealed by the tests. DISCUSSION. In the only slightly stressful ophthalmic surgery, remarkable events were noted particularly during the induction of anaesthesia. The critical decreases and increases of SAP might be related to the autonomic dysfunction, because of the hypersensitivity of a partly damaged autonomic nervous system or its impaired function. This led to a loss of heart rate variation and adequate blood vessel tone. The severe cardiovascular reactions always went along with clearly pathologic findings in the tests performed. Normal test results in diabetics implied normal cardiovascular reactions, as could be observed in nondiabetics. CONCLUSION. Abnormal cardiovascular reactions in diabetics must be kept in mind. The simple tests specified here can identify such predisposed patients.

Time course of dimension and function of the autologous pulmonary root in the aortic position

Although the autologous, fully vital, and compatible pulmonary root theoretically offers the prospect of an ideal aortic valve substitute, this type of replacement is performed in only a few centers. Major concern relates to the fate of root dimension and function in the systemic circulation and is largely unknown. To investigate the fate of the aortic root, we conducted echocardiographic examinations of eight freestanding pulmonary roots used for aortic valve replacement in adults. The studies were performed at discharge from the hospital and up to 21 months (mean 12.5 +/- 6.6 months) after the operation, as well as in 26 matched control subjects. There were no significant differences between the first and second postoperative studies regarding the root diameter (mean 26.6 +/- 2.1 mm and 27.6 +/- 2.6 mm, respectively), which was within control limits, the maximum transvalvular pressure gradient (mean 4.6 +/- 1.2 mm Hg and 6.6 +/- 2.1 mm Hg, respectively), the maximum leaflet separation (mean 22.1 +/- 1.4 mm and 22.1 +/- 1.8 mm, respectively), and the degree of insufficiency. At the first study, grade I aortic regurgitation was found in four patients and grade I-II in one patient. Regurgitation increased slightly in one patient with an abnormal leaflet. In three patients primary grade I regurgitation disappeared. These data suggest that the pulmonary root in the aortic position can withstand systemic circulation without changes in dimension and function for up to 21 months. Furthermore, some evidence is provided to indicate that in certain cases the viable autograft may adapt to systemic pressure, as indicated by the disappearance of primary regurgitation.

[Nifedipine versus nitroglycerin in aortocoronary bypass surgery. The effect on hemodynamics, kidney function and homologous blood requirement]

Even during adequate general anesthesia, hypertension is a common phenomenon in patients undergoing aortocoronary bypass grafting (CABG). In such cases application of vasodilators is recommended in order to decrease myocardial oxygen consumption. This study was performed to compare two commonly used substances, i.e., nitrates and nifedipine, with regard to their influence on hemodynamics, renal blood flow, kidney function, and the requirement for homologous blood transfusions. METHODS. Forty-four patients gave their informed consent to the study. They were randomly divided into 2 groups: group 1 received nitroglycerin (3.0 micrograms/kg.min), group 2 nifedipine (Adalat, 0.5 microgram/kg.min) in order to prevent hypertension in the phase before onset of cardiopulmonary bypass (CPB). Anesthesia was induced by etomidate and succinylcholine and maintained as a modified neuroleptanalgesia with fentanyl (up to 50 micrograms/kg), midazolam (0.3 mg/kg.h), and pancuronium (0.1 mg/kg). Systolic blood pressure was kept within the range of 120-160 mm Hg; in case of higher values boluses of either 0.25 mg nitroglycerin or 0.5 mg nifedipine were administered. Cardiac index, stroke volume index, rate-pressure product, intrapulmonary shunt, and pulmonary and total peripheral resistances were evaluated at five predefined points: (1) after induction of anesthesia; (2) before incision; (3) before cannulating the aorta; (4) after decannulating the aorta; and (5) at the end of operation. Creatinine and free-water clearances as well as sodium and potassium excretion were calculated for three phases of the operation: (A) induction of anesthesia--onset of CPB; (B) during CPB; and (C) end of CPB--end of operation. CPB was performed using a membrane oxygenator (Sorin 51) and a nonpulsatile blood flow of 2.5 1/min.m2, which was reduced during mild hypothermia of 30-32 degrees C to 1.7 l/min.m2. Mean arterial pressure in both groups was kept at approximately 70 mm Hg. In case of lower pressures norepinephrine (50-100 micrograms/bolus) was administered; higher pressures were treated as described above. Volume substitution was performed initially by 500 ml hydroxyethyl starch and continued, if necessary, by homologous blood or 5% human albumin in order to keep the hematocrit greater than 30 in the phases before and after CPB. RESULTS. Group 2 showed significantly higher values of cardiac index and stroke volume index at point 3 while the rate-pressure product was clearly lower, indicating better myocardial performance and lower oxygen consumption than in group 1. Creatinine and free-water clearances in all three phases did not differ. However, sodium excretion during CPB was significantly higher in the nifedipine group while potassium excretion showed no differences. The average requirement for blood and blood substitutes was lower in group 2, but the difference could not be confirmed statistically because of the large dispersion of values. Nevertheless, 4 patients in the nifedipine group but no patient in group 1 did not need homologous blood transfusion. CONCLUSION. In comparison to nitrates, nifedipine showed some advantages in the treatment of hypertension during CABG: (1) it provided better myocardial performance; (2) it had a more reliable but not too long-lasting effect on elevated total peripherial resistance, leading to better hemodynamic stability; and (3) by not affecting the capacitance vessels it may necessitate fewer homologous blood transfusions.