Guidelines for the treatment of severe sepsis and septic shock: hemodynamic resuscitation

Sepsis has a high incidence, mortality and cost and is the main cause of death in intensive care units. Early recognition and treatment have been clearly associated with a better prognosis. Establishing new guidelines is a fundamental step for improving treatment. Patients with clear signs of hypoperfusion should undergo hemodynamic optimization. This guideline addresses the main strategies in the literature that are clinically available.

Estimate of the economic impact of implementing an in hospital protocol for the early detection and treatment of severe sepsis in public and private hospitals in southern Brazil

OBJECTIVE

To analyze the economic impact of an early sepsis detection protocol in two general hospitals.

METHODS

We analyzed data collected from a prospective study of septic patients before and after the implementation of a protocol for early diagnosis of severe sepsis. We conducted a cost-effectiveness analysis comparing: mortality rate, cost of sepsis treatment and indirect costs attributed to years of productive life lost to premature death in both phases.

RESULTS

Two hundred seventeen patients were included, 102 in phase I and 115 in phase II. After protocol implementation, in private and public hospital, mortality rates decreased from 50% to 32.2% and from 67.6% to 41% (p < 0.05). The mean years of productive life lost due to sepsis decreased from 3.18 to 0.80 and 9.81 to 4.65 (p < 0.05), with a mean gain of 2.38 and 5.16 years of productive life, for each septic patient. Considering Brazilian gross domestic product per capita, estimated productivity loss due to sepsis decreased between 3.2 and 9.7 billion US dollars, varying based on the incidence of sepsis. Hospital costs were similar in both phases.

CONCLUSION

A protocol for early detection and treatment of in-hospital septic patients is highly cost-effective from a societal perspective.

Cardiogenic shock associated with subarachnoid hemorrhage

Systemic complications are frequent in subarachnoid hemorrhage patients. Among these complications, electrocardiographic abnormalities simulating ischemic cardiomyopathy may occur, possibly associated with myocardial dysfunction. This manuscript aims to report a case of subarachnoid hemorrhage associated with myocardial dysfunction and cardiogenic shock. A 45 years old woman was admitted with subarachnoid hemorrhage and coma, showing Glasgow scale = 7, Hunt-Hess = 5 and Fischer computed tomography classification = 3. On the second day, the patient underwent anterior cerebral communicant artery aneurysm embolization. The clinical evaluation revealed diffuse pulmonary infiltration, dyspnea and hypotension. Additional tests showed electrocardiographic lateral wall repolarization changes and elevated creatine kinase-MB fraction (36U/L). The cardiac index was 2.03 L/minute/m², Vascular systemic resistance was 3728 dynes.sec/cm². The non-responsiveness to volume demonstrated a cardiogenic shock pattern. The ventricular ejection fraction was 39%. The coronariography was normal, showing no obstructive lesions. Six days later the patient was removed from respiratory support and after eight days the dobutamine infusion was discontinued. The ejection fraction recovered up to 65%. Serial transcranial Doppler evaluations did not show vascular spasm. After ten days the patient was discharged from the intensive care unit. Patients with subarachnoid hemorrhage may be complicated with ventricular dysfunction and cardiogenic shock, increasing the cerebral ischemia risk. Diagnosis optimization and hemodynamic stabilization are essential to minimize the risk of cerebral vasospasm and ischemia.

Early detection strategy and mortality reduction in severe sepsis

OBJECTIVE

To evaluate the impact of implementing an institutional policy for detection of severe sepsis and septic shock.

METHODS

Study before (stage I), after (stage II) with prospective data collection in a 195 bed public hospital.. Stage I: Patients with severe sepsis or septic shock were included consecutively over 15 months and treated according to the Surviving Sepsis Campaign guidelines. Stage II: In the 10 subsequent months, patients with severe sepsis or septic shock were enrolled based on an active search for signs suggesting infection (SSI) in hospitalized patients. The two stages were compared for demographic variables, time needed for recognition of at least two signs suggesting infection (SSI-Δt), compliance to the bundles of 6 and 24 hours and mortality.

RESULTS

We identified 124 patients with severe sepsis or septic shock, 68 in stage I and 56 in stage II. The demographic variables were similar in both stages. The Δt-SSI was 34 ± 54 hours in stage I and 7 ± 8.4 hours in stage II (p <0.001). There was no difference in compliance to the bundles. In parallel there was significant reduction of mortality rates at 28 days (54.4% versus 30%, p <0.02) and hospital (67.6% versus 41%, p <0.003).

CONCLUSION

The strategy used helped to identify early risk of sepsis and resulted in decreased mortality associated with severe sepsis and septic shock.

Potential drug interactions prevalence in intensive care units

OBJECTIVES

Drug interactions occur when effects and/or toxicity of a drug are affected by presence of another drug. They are usually unpredictable and undesirable. A study was conducted to verify the prevalence and clinical value of potential drug interactions in intensive care units

METHODS

All patients, of three intensive care units were included in a cross-sectional study, over a period of two months. Patients with less than a 2 days length of stay were excluded. Data were collected from twenty-four hour prescriptions and all possible paired combinations drug-drug were recorded. Prevalence and clinical value (significance) were checked at the end of follow-up.

RESULTS

One hundred and forty patients were analyzed, 67.1% presented with some significant potential drug interactions and of the 1069 prescriptions, 39.2% disclosed the same potential. Of 188 different potential drug interactions, 29 were considered highly significant. Univariate analysis showed that in the group with significant potential drug interactions a higher number of different drugs, drugs/day had been used, there were more prescribing physicians and extended stay in intensive care units. Adjusted to the multivariate logistic regression model, only the number of drugs/day correlated with increased risk of significant potential drug interaction (p = 0.0011) and, furthermore that use of more than 6 drugs/day increased relative risk by 9.8 times.

CONCLUSIONS

Critically ill patients are submitted to high risk of potential drug interactions and the number of drugs/day has a high positive predictive value for these interactions. Therefore, it is imperative that critical care physicians be constantly alert to recognize this problem and provide appropriate mechanisms for management, thereby reducing adverse outcomes.

Genotoxicity of N-nitrosodicyclohexylamine in V79 cells in the sister chromatid exchange test and the single cell gel assay

Dicyclohexylaminexnitrite is used in chemical formulations as an anti-corrosion agent. N-Nitrosodicyclohexylamine (N-NO-DCHA) can be formed by nitrosation from dicyclohexylamine during the application of these formulations. As most of the nitrosamines are genotoxic carcinogens, the genotoxic potential of N-NO-DCHA was investigated in V79 Chinese hamster cells in the single cell gel assay and the sister chromatid exchange (SCE) test. In addition, N-NO-DCHA cytotoxicity was determined in the neutral red assay. Neutral red uptake was suppressed up to 50% after 24 h incubation at a concentration of approximately 135 microM. In the single cell gel assay, a significantly elevated and dose-dependent induction of DNA lesions was detected in a concentration range from 5 microM to 100 microM (P<0.001). The use of proteinase K (1 mg/ml) in the lysing solution did not influence these results. In the SCE analysis, a significant induction of SCE was found at a minimum concentration of 5 microM N-NO-DCHA as well. A dose-dependent SCE induction could be detected up to the maximum concentration tested in the assay (100 microM). In conclusion, N-NO-DCHA is genotoxic in V79 cells in the single cell gel assay and the SCE test. With respect to human health hazard prevention, a substitution of dicyclohexylaminexnitrite in chemical formulations used to prevent corrosion is recommended.

Genotoxic effects of N-nitrosodicyclohexylamine in isolated human lymphocytes

Dicyclohexylamine x nitrite is classified as an "experimental equivocal tumorigenic agent" by the National Toxicology Program. Since no genotoxic effects of the substance itself are known, the reported tumorigenic potential of dicyclohexylamine x nitrite could be due to generation of N-nitrosodicyclohexylamine (N-NO-DCHA), which occurs under conditions of use and can be detected in foils that contain dicyclohexylamine x nitrite. Therefore, we investigated possible mutagenic properties of N-NO-DCHA in the Ames test and the cytokinesis-block micronucleus assay with human lymphocytes. Since N-NO-DCHA is not commercially available, the substance was synthesized and purified by thin-layer chromatography. Identity was confirmed by gas chromatography/mass spectroscopy (GC/MS) and 1H- and 13C-NMR. More than 97% purity was achieved. Stability and availability in the solvent were checked by GC/MS. N-NO-DCHA induced micronuclei in isolated human lymphocytes at a dose range of 15-100 micrograms/ml (= 71.4-476.2 microM), exceeding the base rate significantly at one or two nontoxic concentrations in four out of six experiments. For the Ames test, arochlor-1254-, beta-naphthoflavone/phenobarbital- and pyrazole-induced S9-fractions were used with Salmonella typhimurium TA100, TA1535, TA98 and TA104. No effects were seen in the Ames test, with the exception of microcolony induction at doses higher than 250 micrograms (= 1.2 mmol) N-NO-DCHA/plate using TA104 and 20% arochlor-1254 induced S9 at pH 6.5. In conclusion, N-NO-DCHA was negative in the Ames test using TA98, TA100 and TA1535, inconclusive using TA104, and weakly genotoxic in the in vitro micronucleus test with isolated human lymphocytes. With regard to the tumorigenicity of the majority of nitrosamines, our data underline the necessity of further studies on possible genotoxic effects of N-NO-DCHA.

Mutagenicity of N-nitrosodiethylamine in the Ames test with S. typhimurium TA1535 is due to volatile metabolites and is not dependent on cytochrome P4502E1 induction

N-Nitrosodiethylamine (NDEA) is carcinogenic in all investigated animal species at relatively low dosages. No threshold has been detected for these carcinogenic effects. The substance has been extensively investigated in various in vitro systems, revealing only weak mutagenicity at relatively high dosages. We reinvestigated NDEA in the Ames test with Salmonella typhimurium TA1535 to establish appropriate modifications of the standard Ames test protocol, to achieve a dose-dependent mutagenic response at a reasonably low dose range. Two main modifications were evaluated. Since the metabolism of dialkylnitrosamines is postulated to be mainly dependent on cytochrome P4502E1, a pyrazole-induced rat liver S9 was applied. The second modification involved a gastight preincubation, since metabolites of NDEA might evaporate from the incubation mixture. Cytochrome P4502E1 induction in Wistar rats was achieved by pyrazole treatment. For comparison, a rat liver S9-fraction produced by beta-naphtoflavone/phenobarbital induction was used. N-Nitrosopyrrolidine served as positive control for pyrazole-induced S9-mix with TA1535. NDEA showed no mutagenic response under all test conditions in the presence of pyrazole-induced S9-mix. A strong mutagenic response, exceeding the base rate up to 15-fold at a dose range of 25-1000 microg/plate, was observed using beta-naphtoflavone/phenobarbital-induced S9-mix, gastight preincubation and TA1535. In conclusion the Ames test with gastight preincubation can be useful for the testing of volatile compounds or substances leading to gaseous metabolites. The weak response of NDEA in the Ames test observed previously seems mainly to be due to the volatile character of its mutagenic metabolites. Our results do not support the hypothesis that cytochrome P4502E1 is a major toxifying enzyme for the formation of Ames-test-positive metabolites from NDEA.

Homozygous gene deletions of the glutathione S-transferases M1 and T1 are associated with thimerosal sensitization

OBJECTIVE

Thimerosal is an important preservative in vaccines and ophthalmologic preparations. The substance is known to be a type IV sensitizing agent. High sensitization rates were observed in contact-allergic patients and in health care workers who had been exposed to thimerosal-preserved vaccines. There is evidence for the involvement of the glutathione system in the metabolism of thimerosal or its decomposition products (organomercury alkyl compounds). Thus detoxification by polymorphically expressed glutathione S-transferases such as GSTT1 and GSTM1 might have a protective effect against sensitization by these substances.

METHODS

To address this question, a case control study was conducted, including 91 Central European individuals with a positive patch-test reaction to thimerosal. This population was compared with 169 healthy controls and additionally with 114 individuals affected by an allergy against para-substituted aryl compounds. The latter population was included in order to test whether possible associations were due to substance-specific effects, or were a general feature connected with type IV immunological diseases. Homozygous deletions of GSTT1 and GSTM1 were determined by polymerase chain reaction.

RESULTS

Glutathione S-transferase M1 deficiency was significantly more frequent among patients sensitized to thimerosal (65.9%, P = 0.013) compared with the healthy control group (49.1%) and the "para-compound" group (48%, P = 0.034). Glutathione S-transferase T1 deficiency in the thimerosal/mercury group (19.8%) was barely elevated versus healthy controls (16.0%) and the "para-compound" group (14.0%). The combined deletion (GSTT1-/GSTM1-) was markedly more frequent among thimerosal-sensitized patients than in healthy controls (17.6% vs. 6.5%, P = 0.0093) and in the "para-compound" group (17.6% vs. 6.1%, P =0.014), revealing a synergistic effect of these enzyme deficiencies (healthy controls vs. thimerosal GSTM1 negative individuals, OR = 2.0 [CI = 1.2-3.4], GSTT1-, OR = 1.2 [CI = 0.70-2.1], GSTM1/T1-, OR = 3.1 [CI = 1.4-6.5]).

CONCLUSIONS

Since the glutathione-dependent system was repeatedly shown to be involved in the metabolism of thimerosal decomposition products, the observed association may be of functional relevance.

Health complaints and immunological markers of exposure to bioaerosols among biowaste collectors and compost workers

OBJECTIVES

In a cross sectional study, work related health complaints and diseases of 58 compost workers and 53 biowaste collectors were investigated and compared with 40 control subjects. Levels of specific IgG antibodies to moulds and bacteria were measured as immunological markers of exposure to bioaerosols.

METHODS

With a standardised protocol, the participants of the study were interviewed for work related symptoms, conditions of exposure to bioaerosols at their workplaces, exposure to bioaerosols from other sources, atopic diseases, and smoking habits. They were clinically examined by physicians specialised in occupational medicine. Also, concentrations of specific IgG antibodies against antigens of moulds and actinomycetes occurring regularly at these workplaces were measured and compared with the health complaints of the workers.

RESULTS

Compost workers had significantly more symptoms and diseases of the airways (p=0.003) and the skin (p=0.02) than the control subjects. Health complaints of biowaste collectors did not differ significantly from those of the control group. Subjects with atopic diseases were underrepresented in the compost workers (p=0.003). Significantly increased antibody concentrations against fungi and actinomycetes were measured in workers at composting plants. The concentrations in biowaste collectors did not differ significantly from those in the control subjects. A significant association between the diseases and increased antibody concentrations were found in the compost workers.

CONCLUSION

The high exposure to bioaerosols of compost workers is significantly associated with a higher frequency of health complaints and diseases as well as higher concentrations of specific antibodies against moulds and actinomycetes. A healthy worker effect is indicated by the underrepresentation of atopic diseases among the compost workers compared with biowaste collectors and the control group.

N-acetyltransferase 1 and 2 polymorphisms in para-substituted arylamine-induced contact allergy

Sensitization to arylamines such as p-phenylenediamine is frequently diagnosed in patients with allergic contact dermatitis. Reactive metabolites of p-phenylenediamine might be produced in the skin by O-acetylation of N-hydroxylamines catalysed by local N-acetyltransferases (NATs). In this study, we tested whether genetic polymorphisms of NATs, which are known to affect enzyme activity, may influence the susceptibility to para-substituted arylamine-induced contact eczema. Using polymerase chain reaction and restriction enzyme analysis, the distribution of polymorphisms of NAT1 and NAT2 was investigated in 88 patients sensitized to para-substituted aryl compounds and 123 healthy controls. NAT2 rapid acetylators, i.e. carriers of the NAT2*4 wild-type allele, were more common in the contact allergy (44%) than in the healthy control group [30%; P = 0.042, odds ratio 1.9 (95% confidence interval, CI 1. 05-3.27)]. Slow acetylators carrying the NAT2*5b/2*6a genotype were significantly less frequent among patients [13% vs. 38% in controls; P = 0.009, odds ratio 0.39 (95% CI 0.19-0.78)]. The carriage rate of the NAT1*10 allele, which is supposed to encode for a rapid NAT1 phenotype, was not significantly different between patients and controls [43% vs. 36%; odds ratio 1.5 (95% CI 0.88-2.68)]. Interactions between NAT2*4 and NAT1*10 were suggested by the increased frequency of the NAT2*4/NAT1*10 haplotype in patients (27%) compared with controls [15%; P = 0.039, odds ratio 2.1 (95% CI 1.04-4.04)]. As the NAT1 and NAT2 encoding genes are located in close proximity on chromosome 8p22, the latter finding could at least partly be due to genetic linkage. In fact, a linkage disequilibrium between NAT2*4 and NAT1*10 was observed in the contact allergy (P = 0.0025) and in the control group (P = 0.042). Our data indicate an association between the NAT2*4/NAT1*10 haplotype and contact sensitization to para-substituted aryl compounds. Therefore, acetylation may either enhance contact sensitization or NAT2*4 and NAT1*10 might be linked to an unknown susceptibility factor.

Genotype and phenotype of N-acetyltransferase 2 (NAT2) polymorphism in patients with contact allergy

We investigated whether patients with contact allergy differed from non-contact-allergic, non-atopic controls with regard to genotype and phenotype of the polymorphic enzyme N-acetyltransferase 2 (NAT2). 55 contact-allergic patients recruited from the Information Network of Departments of Dermatology (IVDK) were compared to 85 controls from among local health care personnel. NAT2 activity was calculated from HPLC analysis of the ratio of the caffeine metabolites 5-acetylamino-6-formylamino-3-methyluracil (AFMU) and 1-methylxanthine (1MX) in the urine. NAT2 genotype was determined by polymerase chain reaction (PCR). A statistically significantly increased proportion of rapid acetylators was found in contact-allergic patients. This may have 2 possible implications: acetylation may enhance contact sensitization; or NAT2 status may be a genetic marker for contact sensitizability.

Bacterial mutagenicity of 2-chloro-1,3-butadiene (chloroprene) caused by decomposition products

Since the literature on genotoxicity of 2-chloro-1,3-butadiene (chloroprene) is controversial, the mutagenicity of this compound was reinvestigated with respect to its chemical stability. Because of the volatility of chloroprene, Ames tests with S. typhimurium TA 100 were carried out with gas-tight preincubation. Propylene oxide, a volatile direct mutagen, served as a positive control. Benzo[a]pyrene was used as a control for an indirect mutagen. Using this experimental regimen, freshly distilled chloroprene was not mutagenic. However, a mutagenic effect occurred linearly with increasing age of the chloroprene distillates. Aged chloroprene gave the same positive results whether preincubation was gas-tight or not. Analysis by gas chromatography (GC) revealed several decomposition products in aged chloroprene distillates. The direct mutagenicity towards TA 100 correlated with the integrated amounts of four of these substances; these substances always occurred in the same relative ratio. When chloroprene was kept under anaerobic conditions, products occurred with time which were partly different from those obtained under aerobic conditions. The direct mutagenicity of anaerobically aged chloroprene was only weak, but the mutagenic effect was enhanced about two- to threefold by addition of S9 mix. Partial identification of chloroprene decomposition products was done by gas chromatography-mass spectrometry (GC-MS): major byproducts of chloroprene, probably responsible for mutagenic properties of aged chloroprene samples, were cyclic chloroprene dimers.