Background: Travellers infected with Schistosoma spp. might be pauci- or even asymptomatic on first presentation. Therefore, schistosomiasis may remain undiagnosed in this population. Active... Show moreBackground: Travellers infected with Schistosoma spp. might be pauci- or even asymptomatic on first presentation. Therefore, schistosomiasis may remain undiagnosed in this population. Active infection, as evidenced by the presence of the tissue-dwelling worm, can be demonstrated via the detection of adult worm-derived circulating anodic antigen (CAA) utilising a robust well-described lateral flow-(LF) based test applying background-free up-converting reporter particles (UCP). In this prospective study, we assessed the diagnostic value of serum and urine UCP-LF CAA test in comparison with two Schistosoma-specific serological assays detecting antibodies against adult worm antigen-immuno fluorescence assay (AWA-IFA) and against soluble egg antigen-enzyme-linked immunosorbent assay (SEA-ELISA) antigens in travellers.Methods: Samples were collected from 106 Dutch travellers who reported freshwater contact in sub-Saharan Africa and who were recruited up to 2 years after return. Subjects were asked to complete a detailed questionnaire on travel history, water contact, signs and symptoms compatible with schistosomiasis.Results: Two travellers were positive by serum CAA and an additional one by urine CAA. A total of 22/106 (21%) samples were antibody positive by AWA-IFA and 9/106 (9%) by SEA-ELISA. At follow-up 6 weeks and 6 months after praziquantel treatment, all seropositives remained antibody positive whereas CAA was cleared. Seropositivity could not be predicted by the type of fresh water-related activity, country visited or symptoms reported.Conclusion: The low number of UCP-LF CAA positives suggests that in travellers, active infections often do not establish or have very low worm burden. Based on our high seroconversion rates, we conclude that the AWA-IFA assay is the most sensitive test to detect schistosome exposure. Given the lack of predictive symptoms or risk factors, we recommend schistosomiasis screening at least by serology in all travellers with reported freshwater contact in high-endemic areas. Show less
OBJECTIVE\nWe studied the variable effects of norepinephrine infusion on cardiac output in postoperative cardiac surgical patients in whom norepinephrine increased mean arterial pressure. We... Show moreOBJECTIVE\nWe studied the variable effects of norepinephrine infusion on cardiac output in postoperative cardiac surgical patients in whom norepinephrine increased mean arterial pressure. We hypothesized that the directional change in cardiac output would be determined by baseline cardiac function, as quantified by stroke volume variation, and the subsequent changes in mean systemic filling pressure and vasomotor tone.\nDESIGN\nIntervention study.\nSETTING\nICU of a university hospital.\nPATIENTS\nSixteen mechanically ventilated postoperative cardiac surgery patients.\nINTERVENTIONS\nInspiratory holds were performed at baseline-1, during increased norepinephrine infusion, and baseline-2 conditions.\nMEASUREMENTS AND MAIN RESULTS\nWe measured mean arterial pressure, heart rate, central venous pressure, cardiac output, stroke volume variation and, with use of inspiratory hold maneuvers, mean systemic filling pressure, then calculated resistance for venous return and systemic vascular resistance. Increasing norepinephrine by 0.04 ± 0.02 μg·kg·min increased mean arterial pressure 20 mm Hg in all patients. Cardiac output decreased in ten and increased in six patients. In all patients mean systemic filling pressure, systemic vascular resistance and resistance for venous return increased and stroke volume variation decreased. Resistance for venous return and systemic vascular resistance increased more (p = 0.019 and p = 0.002) in the patients with a cardiac output decrease. Heart rate decreased in the patients with a cardiac output decrease (p = 0.002) and was unchanged in the patients with a cardiac output increase. Baseline stroke volume variation was higher in those in whom cardiac output increased (14.4 ± 4.2% vs. 9.1 ± 2.4%, p = 0.012). Stroke volume variation >8.7% predicted the increase in cardiac output to norepinephrine (area under the receiver operating characteristic curve 0.900).\nCONCLUSIONS\nThe change in cardiac output induced by norepinephrine is determined by the balance of volume recruitment (increase in mean systemic filling pressure), change in resistance for venous return, and baseline heart function. Furthermore, the response of cardiac output on norepinephrine can be predicted by baseline stroke volume variation. Show less
Mean systemic filling pressure (Pmsf)is defined as the pressure in the blood vessels during cardiac arrest. Pmsf is an important determinant for venous return to the heart and thus for cardiac... Show moreMean systemic filling pressure (Pmsf)is defined as the pressure in the blood vessels during cardiac arrest. Pmsf is an important determinant for venous return to the heart and thus for cardiac output. This thesis describes a method to measure Pmsf at the bedside in intensive care patients and describes the clinical significance of Pmsf in the intensive care Show less
OBJECTIVE We present a new physiological model that discriminated between changes in the systemic arterial and venous circulation. To test our model, we studied the effects of dobutamine and... Show moreOBJECTIVE We present a new physiological model that discriminated between changes in the systemic arterial and venous circulation. To test our model, we studied the effects of dobutamine and hypovolemia in intact pentabarbital-anesthetized piglets. METHODS Aorta pressure (Pao), central venous pressure (Pcv), mean systemic filling pressure (Pmsf) and cardiac output (CO), were measured in 10 piglets, before, during and after dobutamine infusion (6 µg kg⁻¹ min⁻¹), as well as during hypovolemia (-10 mL kg⁻¹), and after fluid resuscitation to normovolemia. Venous (Rv) and total systemic (Rsys) resistance were determined from Pao, Pcv, Pmsf and CO. The quotient of Rv/Rsys was used to determine the predominant location of vascular changes (i.e. vasoconstriction or dilatation on either venous or arterial side). RESULTS Administration of dobutamine increased heart rate and CO, whereas it decreased Pmsf, Rsys, Rv and Rv/Rsys. The decrease in Rv was significantly greater than Rsys. Pao and Pcv did not change. Hypovolemia decreased CO, Pcv, Pmsf, Rv and Rv/Rsys, but kept Rsys constant and increased heart rate. CONCLUSIONS Hypovolemia and dobutamine differentially alter Pmsf, Rsys, Rv and Rv/Rsys ratio. The increase in CO during dobutamine infusion was attributed to the combined increased cardiac function and decreased Rv. The decrease in CO with hypovolemia was due to a decreased Pmsf but was partly compensated for by a decrease in Rv tending to preserve venous return and thus CO. Show less
