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The effect of blood hematocrit (HCT) on a noninvasive flow estimation algorithm was examined in a centrifugal implantable rotary blood pump (iRBP) used for ventricular assistance. An average flow estimator, based on three parameters, input electrical power, pump speed, and HCT, was developed. Data were collected in a mock loop under steady flow conditions(More)
We describe a three-stage mass spectrometer inlet system suitable for use in operating theatres and evidence of its performance in delay and response times to step changes in oxygen and halothane concentrations. At 55 m and a sampled gas flow of 100mlmin-1, the inlet imposed a delay of 21s and prolonged the 10-90% response to 310ms for oxygen and 510ms for(More)
We describe a 40-yr-old woman who received inhaled nitric oxide (NO) as a therapeutic bridge to heart-lung transplantation for end-stage primary pulmonary hypertension. After 10 yr of increasing disability, the patient presented in October 1993 with severe dyspnea, right ventricular angina, and syncope. As predicted by a prior vasodilator trial,(More)
From the moment of creation to the moment of death, the heart works tirelessly to circulate blood, being a critical organ to sustain life. As a non-stopping pumping machine, it operates continuously to pump blood through our bodies to supply all cells with oxygen and necessary nutrients. When the heart fails, the supplement of blood to the body's organs to(More)
Responses of four rotary blood pumps (Incor, Heartmate II, Heartware, and Duraheart) at a single speed setting to changes in preload and afterload were assessed using the human left ventricle as a benchmark for comparison. Data for the rotary pumps were derived from pressure flow relations reported in the literature while the natural heart was characterized(More)
We propose a dynamical model for mean inlet pressure estimation in an implantable rotary blood pump during the diastolic period. Non-invasive measurements of pump impeller rotational speed (ω), motor power (P), and pulse width modulation signal acquired from the pump controller were used as inputs to the model. The model was validated over a wide range of(More)
In this paper, firstly, we propose a linear time-variant (LTV) model to estimate the mean pulsatile flow (Q<inf>p</inf>) in an implantable rotary blood pump (RBP). Non-invasive measurement of mean pulse-width modulation (PWM) signal acquired from the pump controller was used as an input to estimate the mean pulsatility index of pump rotational speed(More)
This multicenter study examines in detail the spontaneous increase in pump flow at fixed speed that occurs in exercise. Eight patients implanted with the VentrAssist rotary blood pump were subjected to maximal and submaximal cycle ergometry studies, the latter being completed with patients supine and monitored with right heart catheter and echocardiography.(More)
RATIONALE The efficacy of veno-venous extracorporeal membrane oxygenation is limited by the phenomenon of recirculation, which is difficult to quantify. Existing measurement techniques using readily available equipment are unsatisfactory. OBJECTIVES 1) To compare the accuracy of measurements of recirculation made using equations comparing blood oxygen(More)