Intraoperative protective ventilation in patients undergoing major neurosurgical interventions: a randomized clinical trial.

BACKGROUND: Post-operative pulmonary complications (PPC) can develop in up to 13% of patients undergoing neurosurgical procedures and may adversely affect clinical outcome. The use of intraoperative lung protective ventilation (LPV) strategies, usually including the use of a low Vt, low PEEP and low plateau pressure, seem to reduce the risk of PPC and are strongly recommended in almost all surgical procedures. Nonetheless, feasibility of LPV strategies in neurosurgical patients are still debated because the use of low Vt during LPV might result in hypercapnia with detrimental effects on cerebrovascular physiology. Aim of our study was to determine whether LPV strategies would be feasible compared with a control group in adult patients undergoing cranial or spinal surgery. METHODS: This single-centre, pilot randomized clinical trial was conducted at the University Hospital "Maggiore della Carità" (Novara, Italy). Adult patients undergoing major cerebral or spinal neurosurgical interventions with risk index for pulmonary post-operative complications > 2 and not expected to need post-operative intensive care unit (ICU) admission were considered eligible. Patients were randomly assigned to either LPV (Vt = 6 ml/kg of ideal body weight (IBW), respiratory rate initially set at 16 breaths/min, PEEP at 5 cmH2O and application of a recruitment manoeuvre (RM) immediately after intubation and at every disconnection from the ventilator) or control treatment (Vt = 10 ml/kg of IBW, respiratory rate initially set at 6-8 breaths/min, no PEEP and no RM). Primary outcomes of the study were intraoperative adverse events, the level of cerebral tension at dura opening and the intraoperative control of PaCO2. Secondary outcomes were the rate of pulmonary and extrapulmonary complications, the number of unplanned ICU admissions, ICU and hospital lengths of stay and mortality. RESULTS: A total of 60 patients, 30 for each group, were randomized. During brain surgery, the number of episodes of intraoperative hypercapnia and grade of cerebral tension were similar between patients randomized to receive control or LPV strategies. No difference in the rate of intraoperative adverse events was found between groups. The rate of postoperative pulmonary and extrapulmonary complications and major clinical outcomes were similar between groups. CONCLUSIONS: LPV strategies in patients undergoing major neurosurgical intervention are feasible. Larger clinical trials are needed to assess their role in postoperative clinical outcome improvements. TRIAL REGISTRATION: registered on the Australian New Zealand Clinical Trial Registry ( www.anzctr.org.au ), registration number ACTRN12615000707561.

Evaluation of a new extraction platform in combination with molecular assays useful for monitoring immunosuppressed patients.

BACKGROUND: In the immunosuppressed, detection of viral reactivation at the earliest convenience and molecular monitoring are of paramount importance. Nucleic acid extraction has a major impact on the reliability of results obtained from molecular assays. OBJECTIVES: The aim of this study was to investigate the accuracy of the new EMAG® nucleic acid extraction platform and to compare the performance of the new platform to that of the standard NucliSENS® easyMAG® instrument in the routine clinical laboratory. STUDY DESIGN: For accuracy testing, reference material and for comparison studies, clinical specimens were used. In addition, a lab-flow analysis including estimation of hands-on time and that for automated extraction was performed. RESULTS: When accuracy was tested, all 89 results obtained were found to be concordant with the results expected. When 648 clinical results were compared, 85.7% were found to be within ±0.5 log10 unit, 9.5% between ±0.5 and ±1.0 log10 unit, and 4.8% more than ±1.0 log10 unit. The overall time required for nucleic acid extraction of 8 samples in parallel was 94 min for the fully automated extraction mode and 82 min for the partly automated mode with the new platform, and 73 min with the standard instrument. Hands-on time was found to be shorter with the new platform. CONCLUSIONS: The extraction performance of both platforms was found to be similar for EDTA whole blood, BAL, and urine specimens. The total turn-around time for nucleic acid extraction was found to be longer with the EMAG® platform, whereas hands-on time was reduced.

Analytical and clinical performance of a new molecular assay for Epstein-Barr virus DNA quantitation.

Quantitation of EBV DNA has been shown to be a useful tool to identify and monitor patients with immunosuppression and high risk for EBV-associated disease. In this study, the analytical and clinical performance of the new Realquality RS-EBV Kit (AB Analitica, Padova, Italy) was investigated. The clinical performance was compared to that of the EBV R-gene (bioMerieux, Varilhes, France) assay. When the accuracy of the new assay was tested, all results except of one were found to be within ±0.5log10 unit of the expected panel results. Determination of linearity showed a quasilinear curve, the between day imprecision ranged from 18% to 88% and the within run imprecision from 16% to 53%. When 96 clinical EDTA whole blood samples were tested, 77 concordant and 19 discordant results were obtained. When the results for the 69 samples quantifiable with both assays were compared, the new assay revealed a mean 0.31log10 unit higher measurement. The new assay proved to be suitable for the detection and quantitation of EBV DNA in EDTA whole blood in the routine diagnostic laboratory. The variation between quantitative results obtained by the assays used in this study reinforces the use of calibrators traceable to the existing international WHO standard making different assays better comparable.

Genotype impact on HCV RNA levels determined with the VERSANT HCV RNA 1.0 assay (kPCR).

BACKGROUND: Accurate quantitation of hepatitis C virus (HCV) RNA is mandatory for the management of anti-HCV therapy. OBJECTIVES: The genotype-dependent performance of the new commercially available VERSANT HCV RNA 1.0 Assay (kPCR) and the COBAS AmpliPrep/COBAS TaqMan HCV Quantitative Test, version 2.0 was investigated. STUDY DESIGN: The molecular assays for quantitation of HCV RNA were performed according to the manufacturer's package insert instructions. HCV genotypes/subtypes/isolates, and mutations in the 5'NCR were detected by direct sequencing. RESULTS: When members of a worldwide HCV performance panel including HCV subtypes 1a, 1b, 2a, 3b, and 4a were tested with the Siemens assay and the results were compared with those obtained by the Roche assay, the mean log10 unit differences for members containing HCV subtypes 1a, 1b, 3b, and 4a were found to be within ±0.5 log(10) units. For the panel member containing HCV subtype 2a, the HCV RNA concentration was found to be >0.5 log(10) units lower with the Siemens assay. When clinical samples were tested, the HCV RNA concentration of all samples containing HCV subtype 2a were found to be >0.5 log(10) units lower with the Siemens assay while that of certain HCV subtype 3a and 4a isolates were found to be >1.0 log(10) units lower. CONCLUSION: The VERSANT HCV RNA 1.0 Assay substantially underestimates HCV RNA concentrations in HCV subtype 2a samples and in HCV subtype 3a and 4a samples containing certain isolates. This may be caused by mismatches with the target sequences due to the primer and/or probe design.

Increase of HCV RNA concentration during hemodialysis treatment in patients with chronic hepatitis C.

BACKGROUND: In hemodialysis (HD) patients, a decrease of serum HCV RNA concentration during HD has been reported. OBJECTIVES: To evaluate the effect of two different extracorporeal blood treatments, HD and hemodiafiltration (HDF), on HCV RNA concentration under standardized conditions. STUDY DESIGN: Eleven chronic HD patients with chronic hepatitis C (CHC) and thirty-three non-uremic patients with CHC as controls were studied. Blood samples were collected at baseline (t=0 min), 30 min (t=30), and 180 min (t=180) after start of HD or HDF. HCV RNA concentrations were determined by a real-time PCR assay. Values obtained 30 min and 180 min after start of HD or HDF were adjusted according to the ultrafiltration-induced hemoconcentration. RESULTS: Baseline HCV RNA concentrations were found to be similar in dialysis patients and controls (2.9E+06 vs. 5.8E+06 IU/ml). After adjustment for hemoconcentration, no significant differences of HCV RNA concentrations were observed when HD versus HDF treatments and blood samples collected pre versus those collected post membrane were compared. Adjusted HCV RNA concentrations increased by 13% (not significant) at 30 min and by 56% (p<0.001) at 180 min after start of HD or HDF. Inhibitory effects on PCR through heparin and uremic toxins could be excluded. CONCLUSIONS: In contrast to recent publications, a significant increase of serum HCV RNA within 180 min after start of HD or HDF was observed. Changes in serum HCV RNA concentration are independent from HD and HDF procedures, dialysis membrane, heparin concentration, and uremic toxins.