Evaluation of dyspnea of unknown etiology in HIV patients with cardiopulmonary exercise testing and cardiovascular magnetic resonance imaging.

AIM: Human Immunodeficiency Virus (HIV) patients commonly experience dyspnea for which an immediate cause may not be always apparent. In this prospective cohort study of HIV patients with exercise limitation, we use cardiopulmonary exercise testing (CPET) coupled with exercise cardiovascular magnetic resonance (CMR) to elucidate etiologies of dyspnea. METHODS AND RESULTS: Thirty-four HIV patients on antiretroviral therapy with dyspnea and exercise limitation (49.7 years, 65% male, mean absolute CD4 count 700) underwent comprehensive evaluation with combined rest and maximal exercise treadmill CMR and CPET. The overall mean oxygen consumption (VO2) peak was reduced at 23.2 ± 6.9 ml/kg/min with 20 patients (58.8% of overall cohort) achieving a respiratory exchange ratio > 1. The ventilatory efficiency (VE)/VCO2 slope was elevated at 36 ± 7.92, while ventilatory reserve (VE: maximal voluntary ventilation (MVV)) was within normal limits. The mean absolute right ventricular (RV) and left ventricular (LV) contractile reserves were preserved at 9.0% ± 11.2 and 9.4% ± 9.4, respectively. The average resting and post-exercise mean average pulmonary artery velocities were 12.2 ± 3.9 cm/s and 18.9 ± 8.3 respectively, which suggested lack of exercise induced pulmonary artery hypertension (PAH). LV but not RV delayed enhancement were identified in five patients. Correlation analysis found no relationship between peak VO2 measures of contractile RV or LV reserve, but LV and RV stroke volume correlated with PET CO2 (p = 0.02, p = 0.03). CONCLUSION: Well treated patients with HIV appear to have conserved RV and LV function, contractile reserve and no evidence of exercise induced PAH. However, we found evidence of impaired ventilation suggesting a non-cardiopulmonary etiology for dyspnea.

Transfusion practices for treatment of dogs undergoing splenectomy for splenic masses: 542 cases (2001-2012).

OBJECTIVE: To describe transfusion practices for treatment of dogs undergoing splenectomy for splenic masses. DESIGN: Retrospective case series. ANIMALS: 542 client-owned dogs. PROCEDURES: Medical records of dogs that underwent splenectomy for splenic masses at 2 referral institutions were reviewed. Variables of interest were compared between dogs that did and did not undergo transfusion. Multiple logistic regression analysis was performed to assess associations of transfusion with death during hospitalization and with 30- and 180-day survival rates. RESULTS: Transfusions were administered to 240 of 542 (44%) dogs; packed RBCs were the most frequently administered blood product. On admission, dogs that subsequently received transfusions had higher mean illness severity score, heart rate, respiratory rate, blood lactate concentration, and prothrombin time, with lower mean PCV, platelet count, serum total solids and albumin concentrations, and base deficit than dogs that did not receive transfusions. Hemoperitoneum and malignancy, especially hemangiosarcoma, were more common in the transfusion group. Overall, 500 of 542 (92%) dogs survived to discharge. Dogs that received transfusions had higher odds of death or euthanasia while hospitalized and lower odds of surviving to 30 or 180 days after hospital discharge than dogs that did not. CONCLUSIONS AND CLINICAL RELEVANCE: Evidence of shock, anemia, and hypocoagulability were apparent triggers for the decision to perform blood transfusion in dogs undergoing splenectomy for splenic masses and were likely attributable to hemoperitoneum and related hypovolemia. Dogs undergoing transfusion more commonly had malignant disease and had greater odds of poor long-term outcome, compared with dogs that did not undergo transfusion.

Miniaturisation and simplification of solid-state proton activity sensors for non-aqueous media and ionic liquids.

This work is the further development of the previous pH (effective) sensor work where a biologically derived proton-active redox centre - riboflavin (RFN) - was entrapped into a vapour phase polymerised poly(3,4-ethylenedioxythiophene) film and ferrocene (Fc) dissolved in the sample solution was used as an internal reference redox couple. Here, we report a disposable solid state pH (effective) sensor where we successfully incorporated both RFN and Fc into a single solid state electrode. The electrodes were then used for pH (effective) sensing where water is not required. The system was further miniaturised and simplified from a 3 electrode to a 2 electrode setup with the working electrode area being as small as 0.09 mm(2). The sensors show the ability to measure pH (effective) in both aqueous and non-aqueous media including ionic liquids (ILs) regardless of their hydrophobicity. This is an important step towards the ability to customise ILs or non-aqueous media with suitable proton activity (PA) for various applications e.g. customised ILs for biotechnological applications such as protein preservation and customised media for PA dependent reactions such as catalytic reactions.