Hemodilution and intravenous perflubron emulsion as an alternative to blood transfusion: effects on tissue oxygenation during profound hemodilution in anesthetized dogs

BACKGROUND: Intravenously administered perfluorocarbon (PFC) emulsions increase oxygen solubility in plasma. PFC might therefore temporarily replace red cells (RBCs) lost during intraoperative hemorrhage. In patients who have undergone hemodilution, the return of autologous blood may be delayed by the administration of PFC, and autologous RBCs may be saved for transfusion after surgical bleeding is stopped and PFC is cleared by the reticuloendothelial system. STUDY DESIGN AND METHODS: In 22 anesthetized, hemodiluted dogs (hemoglobin [Hb] 7 g/dL) breathing 100-percent O2, an intraoperative volume-compensated blood loss was simulated. The efficacy of three therapeutic regimens in maintaining tissue oxygenation was compared: 1) RBC group (n = 7): maintenance of a Hb > 7 g per dL by transfusion of autologous RBCs; 2) PFC group (n = 7): bolus application of a second-generation PFC emulsion (60% wt/vol perflubron) and further acute normovolemic hemodilution (ANH) to a Hb of 3 g per dL; and 3) control group (n = 7): further ANH alone to a Hb of 3 g per dL. Systemic and myocardial oxygenation status and tissue oxygenation were assessed. RESULTS: Autologous RBCs transfused to maintain a Hb of 7 g per dL preserved hemodynamics and tissue oxygenation during blood loss. In the PFC and control groups, heart rate and cardiac index increased significantly in response to further ANH. Tissue oxygenation was not different in the PFC and the RBC groups. Direct comparison of the PFC and control groups revealed better tissue oxygenation in the PFC group, as reflected by significantly higher mixed venous, coronary venous, and local tissue pO2 on liver and skeletal muscle. CONCLUSION: Bolus intravenous administration of 60- percent (wt/vol) perflubron emulsion and further hemodilution from a Hb of 7 g per dL to one of 3 g per dL were as effective as autologous RBC transfusion in maintaining tissue oxygenation during volume-compensated blood loss designed to mimic surgical bleeding.     

Antibiotic cycling to decrease bacterial antibiotic resistance: a 5-year experience on a bone marrow transplant unit

Multidrug-resistant pathogens have important effects on clinical outcomes. Antibiotic cycling is one approach to control anti-microbial resistance, but few studies have examined cycling in hematology-oncology units. Antibiotic cycling was implemented in January 1999 at our hematology-oncology unit, alternating piperacillin-tazobactam (pip-tazo) and cefepime in 3 months periods, until June 2004. Clinical isolates were compared in post- and pre-intervention periods and with the susceptibility among the solid organ transplant intensive care unit (TICU) isolates. The rate of Gram-negative isolates remained stable. Among Gram-negatives, susceptibility to cefepime and pip-tazo remained stable. There was an increase in Enterococcus spp. (P=0.007), and susceptibility to ampicillin and vancomycin decreased (odds ratio (OR): 0.04, 95% confidence interval (CI): 0.17-0.89 and OR: 0.23, 95% CI: 0.09-0.58). Compared with the TICU, there was increased susceptibility to pip-tazo and cefepime among enterics (OR: 7.32, 95% CI: 4.44-12.07 and OR: 8.82, 95% CI: 2.1-37.13) and Pseudomonas aeruginosa (OR: 4.27, 95% CI: 1.47-12.4 and OR: 4.61, 95% CI: 1.75-12.1) and decreased susceptibility to ampicillin and vancomycin among enterococci (OR: 0.44, 95% CI: 0.30-0.63 and OR: 0.38, 95% CI: 0.26-0.56). Cycling was associated with preserved antibiotic susceptibility among Gram-negatives, but with an increase in Enterococcus spp. and vancomycin and ampicillin resistance among enterococci.     

HIV-1 control after transient antiretroviral treatment initiated in primary infection: role of patient characteristics and effect of therapy

BACKGROUND: The occurrence of viral control after interruption of an antiretroviral treatment (ART) initiated during primary HIV-1 infection (PHI) is rare and the frequency and predictive factors of such a control are unknown. METHODS: Within the French ANRS PRIMO Cohort, 164 patients interrupted ART initiated during PHI. We compared patients whose viral load (VL) remained undetectable (<50 copies/ml) or low (50-500 copies/ml) 1 year after ART interruption to those who evidenced a rapid viral rebound. RESULTS: After ART interruption, VL remained undetectable for a median time of 4.5 years in 14 patients ('post-ART controllers') and low in another 14 patients for a median time of 1.5 years. Post-ART controllers also maintained higher CD4(+) T-cell counts compared to other patients. Female gender, a high CD4(+) T-cell count and low VL during PHI, and a high CD4(+) T-cell count and low HIV DNA levels at interruption, were associated with post-ART HIV control. Treatment characteristics did not differ between controllers and non-controllers. Post-ART controllers had lower specific CD8(+) T-cell frequencies and CD8(+) T-cell activation on ART and after ART interruption than non-controllers. CONCLUSIONS: Few patients maintain very low VL after interruption of treatment initiated during PHI. Early patient characteristics were the main factors of viral control, although early initiation of ART and the effect of ART on reservoir might contribute to control.