J Elstrodt

Universitair Medisch Centrum Groningen, Groningen, Groningen, Netherlands

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Publications (30)50.72 Total impact

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    ABSTRACT: Hemodynamic instability, mostly due to vertical lifting of the heart, is usually observed during beating-heart surgical procedures. However, some hemodynamic parameters, such as coronary blood flow, are not routinely measured. A digital computer model of the circulation able to simulate and analyze the effects of heart lifting and the Trendelenburg maneuver, and thus supply detailed hemodynamic information to the clinicians would provide a useful analytical tool. A lumped parameters model of the circulation was applied to both beta-blocked and not beta-blocked pigs. The results confirmed a drop of cardiac output and coronary flow during heart lifting and a rise of both variables after the Trendelenburg maneuver for beta-blocked animals. In not beta-blocked pigs, the analysis was more complex but the model reproduced experimental data and permitted coronary flow to be estimated. These results showed the feasibility of numerical simulation for specific circulatory conditions encountered during beating-heart surgery.
    Artificial Organs 02/2007; 31(1):73-9. · 1.96 Impact Factor
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    ABSTRACT: Cardiopulmonary bypass (CPB) is known to impair the integrity of the gastrointestinal tract. However, little is known about the movement behavior of the gastrointestinal tract during CPB. This study was aimed to assess the gastrointestinal motility with sonomicrometry, a distance measurement using ultrasound, in a porcine model of CPB. Twelve pigs weighing 70-112 kg were having a standard hypothermic CPB for 120 min either with the nonpulsatile flow (n = 6) or the pulsatile flow (n = 6). Before CPB, piezoelectric echo crystals were placed either along the longitudinal or the circular axis of the pylorus. Patterns of gut movement and the total sonomicrometric activity (TSA) were recorded at several time intervals during experiments as qualitative and quantitative parameters of gut motility. Results showed that the intact regular rhythmic pattern of gut movement was detected before CPB. This pattern changed little when CPB started, but it disappeared at 60 min when the body temperature lowered down to 32 degrees Celsius. During the same period, the TSA reduced significantly along the longitudinal as well as the circular directions of the pylorus. There was no significant difference between the nonpulsatile and pulsatile groups. Gut blood flow reduced significantly in both groups, but it was not associated with the reduced sonomicrometric activity. In conclusion, gastrointestinal motility during CPB can be measured qualitatively and quantitatively by sonomicrometry in a large animal model. Suppression of gut motility during CPB does not seem to be associated with the mode of perfusion but with the reduced body temperature during the hypothermic phase of CPB.
    Artificial Organs 08/2006; 30(7):548-53. · 1.96 Impact Factor
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    ABSTRACT: Donor shortage urges optimal use of all lungs available. Ex vivo lung perfusion (EVLP) is a method to evaluate lung function before implantation. EVLP was performed in pigs to evaluate lung function, using two different clinical non-heart-beating (NHS) donor protocols: flush perfusion and topical cooling after 1-h warm ischaemia (n = 5 each). Secondly, we investigated whether EVLP can be used for 6 h ex vivo machine preservation (n = 4). In comparison with topical cooling, flush perfusion preserved lung function better during EVLP. During 6 h normothermic EVLP, gas exchange remained stable; however, the pulmonary artery pressure and ventilation pressure showed a significant increase. EVLP is a reliable method for evaluation of lung graft function. Flush perfusion with Perfadex is preferred above topical cooling in NHB lung donation. Six-hour normothermic EVLP is feasible but should be further improved to make ex vivo machine preservation or treatment of lung grafts successful.
    Transplant International 08/2006; 19(7):589-93. · 3.16 Impact Factor
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    ABSTRACT: Current pulsatile pumps for cardiopulmonary bypass (CPB) are far from satisfactory because of the poor pulsatility. This study was undertaken to examine the efficiency of a novel pulsatile catheter pump on pulsatility and its effect on abdominal organ perfusion during CPB. Twelve pigs weighing 89+/-11 kg were randomly divided into a pulsatile group (n=6) and a non-pulsatile group (n=6). All animals had a CPB for 120 min, aorta clamped for 60 min, temperature down to 32 degrees C, and a perfusion flow of 60 ml/kg/min. In the pulsatile group, a 21 Fr intra-aortic pulsatile catheter, which was connected to a 40 mL membrane pump, was placed in the descending aorta and activated by a balloon pump driver during the first 90 minutes of CPB until aortic declamping. Hemodynamics, organ blood flow, body metabolism, and blood trauma were studied during experiments. Compared with the non-pulsatile group during CPB, the pulsatile group had a higher systolic blood pressure (p<0.01), higher mean arterial pressure (p<0.05), and higher blood flow to the superior mesenteric artery (p<0.05). The hemodynamic energy, indicated by the energy equivalent pressure (EEP) was higher in the gastrointestinal tract and kidney in the pulsatile group (p<0.01, p<0.01). Abdominal organ perfusion status, as indicated by SvO 2 in the inferior vena cava, was higher in the pulsatile group (p<0.05) 30 min after cessation of CPB. Hemolysis indicated by release of free hemoglobin during CPB was similar in the two groups. Applying the pulsatile catheter pump in the descending aorta is effective in supplying the pulsatile flow to the abdominal organs and results in improved abdominal organ perfusion during the ischemic phase of CPB.
    The International journal of artificial organs 02/2005; 28(1):35-43. · 1.76 Impact Factor
  • Asaio Journal - ASAIO J. 01/2004; 50(2).
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    ABSTRACT: To investigate the feasibility of instrument-independent perfusion units for laser Doppler flowmetry, a comparison was performed of two commercial fiberoptic laser Doppler perfusion monitors measuring the same flux situation for two different types of probes. In vivo measurements were performed on the cortex of pig's kidney, with an ultrasonic arterial flow meter as reference. The flow was mainly varied by internal arterial constriction using a balloon catheter. For each probe, instruments are compared in terms of the ratio of laser Doppler flux and arterial flow. For a given probe, the flux-to-flow ratios of the two instruments show a linear mutual relationship for a wide variety of arterial flows and laser Doppler fluxes. In vitro measurements were performed on an aqueous suspension of polystyrene microspheres. For the probe with interfiber distance 500 microm the ratio of the in vivo fluxes appears to agree within 16% to the value found in vitro, while for the 250-microm probe a difference of 28% was found. For a wide range of fluxes, the in vivo flux values of one instrument can be translated into flux values for the other instrument, in spite of the instrumental differences. This enables the user to render experimental results independent of the specific instrument, thus facilitating multi-center studies.
    Microvascular Research 10/2003; 66(2):83-90. · 2.93 Impact Factor
  • Medical device technology 06/2001; 12(4):18-20.
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    ABSTRACT: One of the most important problems with ICD systems is infection. The aim of this study was an in vivo evaluation of the efficacy of defibrillator systems in terms of infection resistance. The polyurethane leads were coupled with heparin and loaded with the antibiotic gentamicin, while the PGs were modified to release gentamicin. Group I was comprised of 10 pigs implanted with either a standard or a modified system for 2 weeks; group II was implanted during 4 weeks. The lead was inserted into the heart wall via the jugular vein. The other end was subcutaneously tunneled to the armpit where the PG was positioned. A cocktail of Staphylococcus aureus and epidermidis was injected at the site of the PG. Evaluation was performed macroscopically, by taking bacterial swabs during explantation and by microscopic processing. The results showed that 3 out of 5 modified defibrillator-systems in group I and 1-2 out of 5 in group II were judged as noninfected, whereas all standard systems were infected. Infection rates of the remaining modified defibrillators showed variances, as found with the standards, from slight to moderate to high, to even high/severe in group II (1x standard and 1x modified). With the modified systems, this may be related to production of humoral factors by an intensified early tissue reaction, as indicated by a swelling at day 6 at the site of the PG. When infected, whether or not modified, usually only Staphylococcus aureus was present. Spreading of infection seemed to occur by inoculation via blood, for example, based on the observation that group II in general showed an increase in infected fibrotic overgrowth in the heart, while infectious problems were low in the jugular vein. It is concluded that the modification at short term shows enhanced infection resistance. An increased infection rate already at 4 weeks, however, indicates that the modification may not hold in the long run. Special attention is needed concerning the more intense early tissue reaction.
    Journal of Biomedical Materials Research 02/2001; 58(4):384-92.
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    ABSTRACT: The Pulsatile Catheter (PUCA) pump is a trans-arterial pulsatile ventricular assist device that can be used for short-term left ventricular support. The separate inflow and outflow valves in the first version of the device (PUCA-I) were replaced by a single inflow/outflow valve in the latest PUCA pump version (PUCA-II). The new combined valve was tested during in vitro (mock circulation) and in vivo experiments for valve leakage, flow resistance, and thrombus formation. During the in vitro experiments a maximum valve leakage of 6% during ejection and 21% during aspiration was found. The maximum flow resistance coefficient (K) was 4. The animal experiments demonstrated that the PUCA-II could be positioned within a few minutes into the left ventricle without X-ray guidance and without using a vascular graft. Thrombi were not found in the combined valve after total pump time of 3 hours, which proved the good washout of the valve. Initial experiments to position the pump in the right ventricle through the pulmonary artery were successful and contributed to the development of a new application for the device.
    The International journal of artificial organs 11/2000; 23(10):697-702. · 1.76 Impact Factor
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    ABSTRACT: The goal of the present study was to develop a large animal model of acute ischemic left ventricular heart failure (LVHF) that can be used to assess the influence of the PUCA pump on the heart and circulatory system under realistic conditions. We tested the hypothesis that mild stenosis of the coronary artery in combination with mild ventricular pacing induces an acute heart failure condition, whereas the separate phenomena themselves do not lead to impaired heart function. Mean aortic pressure (AoP), left ventricular end-diastolic pressure (LVEDP), stroke volume (SV) and myocardial systolic shortening (MSS) were compared 30 minutes after a pacemaker (PM) induced tachycardia in anaesthetized sheep (n=3) without and with +/- 50% stenosis of the proximal LCx. All parameters measured restored to basic levels when stenosis was absent. When the LCx was partially occluded, mild PM-induced tachycardia resulted in decreased AoP (P=0.045) as well as in decreased SV (P=0.048); the LVEDP remained high (P=0.002). Also the recovery of MSS was impaired when stenosis was present (P=0. 002). These values indicate that acute heart failure conditions were present. The technique used proved to be safe and allowed fine-tuning of the demand ischemia by adapting heart frequency to the required heart failure conditions. The model can be used to study the effect of LV mechanical support during acute heart failure conditions.
    The International journal of artificial organs 06/2000; 23(5):325-30. · 1.76 Impact Factor
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    ABSTRACT: The pulsatile catheter (PUCA) pump, a left ventricular assist device, was tested during acute experiments in calves using asynchronous and ECG-synchronous assist modes. The aim of the study is to compare ECG-synchronous and asynchronous assist and to find the optimal driving mode for the PUCA pump with respect to left ventricular myocardial oxygen consumption (LV MVO2), pump flow, and coronary flow. LV MVO2 decreased significantly during the asynchronous (from 7.77 to 6.46 ml/min/100 g) as well as during the ECG-synchronous mode (from 8.88 to 7.84 ml/min/100 g). The pump flow was highest during the ECG-synchronous assist (2.94 L/min), followed by the asynchronous assist (2.79 L/min). The peak coronary flow depended strongly on pump ejection timing and showed the best flow patterns during the ECG-synchronous assist. We concluded that for PUCA pump support both asynchronous and ECG-synchronous assists significantly reduce LV MVO2 and that the pump flow generated is enough to maintain the systemic circulation. However, we find the ECG-synchronous mode preferable because this mode optimizes coronary flow patterns at the same time.
    Artificial Organs 01/2000; 23(12):1117-22. · 1.96 Impact Factor
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    ABSTRACT: To determine, in a rat model of fat malabsorption, the potency of the carbon 13-labeled mixed triglyceride ((13)C-MTG) breath test as a noninvasive, patient-friendly replacement for classic fat balance studies. Study design: Comparison of the percentage of fat absorption, detected by fat balance, with the (13)CO(2) recovery of the (13)C-MTG breath test in rats fed high-fat chow and varying amounts of the lipase inhibitor, orlistat (0, 50, 200, and 800 mg per kilogram of chow), for 5 days. On orlistat administration, total fat absorption decreased from 80.2% +/- 2.2% to 32.8% +/- 3.7% (mean +/- SEM, 0 mg and 800 mg of orlistat per kilogram of chow, respectively; P <.001). Correspondingly, breath (13)CO(2) recovery from (13)C-MTG at 6 hours decreased from 84.5% +/- 7.8% to 42.0% +/- 1.5% of the dose (0 mg and 800 mg of orlistat per kilogram of chow, respectively; P <.001). The 6-hour recovery of breath (13)CO(2) appeared to be highly correlated with the percentage of fat absorption (r = 0.88, P <.001). In rats with fat absorption higher than 70%, however, the coefficient of variation of the (13)C-MTG breath test was 3-fold larger than that of the fat balance. The (13)C-MTG breath test could potentially replace the fat balance method for comparing fat absorption efficacy between groups. Yet, a considerable interindividual variation of the (13)C-MTG breath test under conditions of relatively mild fat malabsorption does not support its application for diagnostic purposes in individuals.
    Journal of Pediatrics 11/1999; 135(4):444-50. · 4.04 Impact Factor
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    ABSTRACT: Purpose. The feasibility of hyperthermic isolated limb perfusion (HILP) with tumor necrosis factor-alpha (TNFalpha ) and cisplatin for the management of osteosarcoma was studied in the canine model.Methods. During seven perfusions in six healthy mongrel dogs (weight 32+/-2 kg) technical aspects of HILP under mild hyperthermia (39- 40) were studied. In five experiments HILP was performed with TNFalpha alone (0.5 mg/l extremity volume), and in two experiments TNFalpha was combined with cisplatin (25 mg/l extremity volume). During the perfusions physiological parameters were monitored and TNFalpha and total cisplatin concentrations were determined.Results. Perfusion conditions (pH, PCO(2) , PO(2), flow and pressure) remained within physiological ranges.Three dogs died within 24 h despite a sublethal systemic concentration of TNFalpha that leaked from the perfusion circuit. Three dogs were terminated; one dog after the second experiment in accordance with Dutch ethical rules; one dog showed an invagination of the small bowel resulting in an ileus; one dog because of necrosis of the perfused limb.Conclusions. This feasibility study in healthy dogs demonstrated that HILP with TNFalpha and cisplatin was associated with a high mortality rate and does not allow us to treat dogs with spontaneous osteosarcoma with TNFalpha and cisplatin HILP. Therefore, an alternative model should be used in the search for the ideal combination of perfusion agents for limb sparing treatment in human osteosarcoma.
    Sarcoma 01/1999; 3(2):89-94.
  • European Journal of Gastroenterology & Hepatology - EUR J GASTROENTEROL HEPATOL. 01/1998; 10(12).
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    ABSTRACT: The pulsatile catheter (PUCA) pump is an intraventricular blood pump that can be introduced into the left ventricular cavity through a superficial artery (transarterially) or directly through the thoracic aorta during open chest conditions. When positioned, the pump aspirates blood from the left ventricle and transports it into the ascending aorta. A pneumatic driving system allows the blood to be ejected in early diastole of every second or third heart beat. The main goal of this study was to develop an easy, fast, safe surgical introduction technique. Four different means of catheter introduction were tested in 20 acute open chest experiments with calves: introduction without any guidance at all, introduction by x-ray guidance only, introduction using a guide wire plus x-ray guidance, and introduction using a guiding pressure catheter. Introducing the PUCA pump catheter into the left ventricular cavity using a pigtail guiding pressure catheter proved to be easy. The large bore pump catheter followed the guiding catheter and passed the aortic valve well. The position of the PUCA pump could be monitored from the pressure patterns derived from the guiding catheter.
    Artificial Organs 06/1997; 21(5):425-7. · 1.96 Impact Factor
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    ABSTRACT: The blood compatibility of ventricular assist devices developed by the Helmholtz Institute Aachen (HA-VAD's) was tested on calves. Seven calves received a non-coated HIA-VAD (control) and three a Bioline heparin coated device. The circulatory support of these HIA-VAD's lasted one week. Mechanical blood cell trauma estimated by hematocrit (Hct), hemoglobin (total Hb) and free plasma hemoglobin (free Hb) levels did not differ in either group. All HIA-VAD's in the control group remained thrombus free, except on one occasion when an inflow cannula was obstructed by a thrombus located in the tip. After circulatory support, the animals in this group seemed clinically healthy. However, thrombus formation was observed in the three heparin coated HIA-VAD's. One animal in this group died from complications after re-operation for pneumothorax on the fifth day of support, whereas the other two animals seemed clinically healthy. In these three animals, a strong decrease in platelet numbers was measured even after 24 hours of support which recovered after 72 hours. This decrease in platelet numbers was associated with a lower degree of platelet aggregation ability stimulated by ADP (p < 0.05). Fibrin(ogen) degradation products (FDP) increased significantly immediately after the implantation procedure (p < 0.05). Fibrinogen levels initially decreased during the implantation procedure, but increased thereafter in both groups. The FDP levels remained high in this group, although the FDP levels in both groups were decreased after the implantation procedure. The ex vivo measured circulating heparin levels were lower in the heparin coated HIV-VAD group despite the equally administrated heparin doses in both animal groups. No differences were measured in either group with regard to white blood cell (WBC) numbers and complement hemolytic activity (CH50). Despite these hemostatic changes, no mechanical trauma could be demonstrated after seven days of circulatory support.
    The International journal of artificial organs 02/1997; 20(1):43-50. · 1.76 Impact Factor
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    ABSTRACT: A novel ventricular assist device (HIA-EMLVAD-AT1, Helmholtz Institute Aachen-Electromechanical Left Ventricular Assist Device-Animal Test Version 1), driven by a uniformly and unidirectionally rotating actuator and a patented hypocycloidic pusherplate displacement gear unit, was developed and tested in an acute animal experiment. The excellent free filling behavior of the pump chamber with a stroke volume of 65 ml is obtained by a 2:3 ejection-filling time relationship. The uniform motor rotation facilitates simple sensorless pre and afterload detection by motor current analysis. In contrast to common apical cannulation, the inlet cannula was placed via the left atrium through the mitral valve into the left ventricle. This connection mode is preferable for left ventricular recovery and preservation. Left atrial, left ventricular, and aortic pressure curves, as well as pulmonary artery flow data, were obtained. The data show very effective unloading of the natural ventricle and demonstrate the feasibility of this novel assist device. Directions for further improvement of technical features were also identified.
    ASAIO Journal 01/1997; 43(4):360-2. · 1.49 Impact Factor
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    ABSTRACT: Helmholtz Ventricular Assist Devices (VAD) are pneumatically driven polyurethane membrane pumps with various volumes. The pumps are placed paracorporeally and connected with commercially available cannulas between the left atrium and aorta (left ventricular assist device) and/or right atrium and pulmonary artery (right ventricular assist device, bi-ventricular assist device). The pumps can be driven with a stand-alone driving system or with a Helmholtz IABP-console interface. Seventeen animal experiments (on calves) with Helmholtz VAD's were performed to evaluate experimental protocols, to optimize surgical techniques, and to improve design and manufacturing techniques. Blood chemistry and cell counts demonstrated that the tested HIA-70 produces low mechanical blood damage. In the course of the animal experiments the Helmholtz VAD's were made totally transparent, whereby they became easy to de-air, efficient, and affordable.
    The Thoracic and Cardiovascular Surgeon 07/1994; 42(3):136-40. · 0.93 Impact Factor
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    ABSTRACT: Transmission pulse oximetry is used for monitoring in many clinical settings. However, for fetal monitoring during labor and in situations with poor peripheral perfusion, transmission pulse oximetry cannot be used. Therefore, we developed a reflectance pulse oximeter, which uses the relative intensity changes of the reflected red and infrared light (red/infrared ratio) to measure the arterial oxygen saturation. The performance of the reflectance pulse oximeter was studied in acute experiments in fetal lambs. By stepwise reduction of the inspired oxygen concentration of the ewe, measurements were done at the fetal scalp at various arterial oxygen saturation levels (17-82%). Reflectance pulse oximeter readings were averaged over periods of 15 s and compared with simultaneously taken fetal arterial blood samples. A calibration curve for the relationship between red/infrared ratio and arterial oxygen saturation was obtained from 53 measurements in four fetal lambs, by linear regression analysis [red/infrared = 4.088-(0.038.SaO2), r = 0.96]. In these experiments, the pulse oximeter showed a precision of 4.7% oxygen saturation around the calibration curve, with a 95% confidence interval of +/- 9.4%.
    Pediatric Research 04/1992; 31(3):266-9. · 2.67 Impact Factor
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    ABSTRACT: The ideal tracheal prosthesis has to permit complete incorporation by epithelialization of the luminal surface. This is not possible with the currently available impermeable solid silicone tube. The authors developed a reinforced, porous polyurethane tubular prosthesis which has the potential for complete incorporation. However, because these prostheses are implanted in a contamined area such as the airway, they all become infected. In order to prevent infection, the authors evaluated the effect of omental wrapping in guinea pigs. The authors' tubular prosthesis was implanted subcutaneously in the abdominal area with the ends open to the air. Ten prostheses were wrapped with omentum and 10 prostheses were not. In 4 weeks, all control prostheses were infected and marsupialized. All the wrapped prostheses remained in place and were macroscopically not infected. Microscopically, all wrapped prostheses were well vascularized and were incorporated by granulation tissue, which did not occur in the prostheses of the control group. From these results the authors conclude that omental wrapping would be an effective way to prevent infection of porous tracheal prostheses in an open-to-the-air situation, and allow rapid tissue ingrowth and incorporation in the host.
    ASAIO transactions / American Society for Artificial Internal Organs 01/1990; 36(3):M438-40.

Publication Stats

168 Citations
50.72 Total Impact Points

Institutions

  • 1992–2007
    • Universitair Medisch Centrum Groningen
      Groningen, Groningen, Netherlands
  • 1987–2005
    • University of Groningen
      • • Centre for Biomedical Technology
      • • Department of Biomedical Engineering
      Groningen, Province of Groningen, Netherlands
  • 2003
    • Universiteit Twente
      Enschede, Overijssel, Netherlands
  • 1990
    • Kyoto Prefectural University of Medicine
      Kioto, Kyōto, Japan