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  • 1
    ISSN: 1619-7089
    Schlagwort(e): Myocardial infarction ; Technetium-99m sestamibi ; Dobutamine stress echocardiography ; Coronary anatomy ; Viability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Rest technetium-99m sestamibi single-photon emission tomography (SPET) has been shown to under-estimate viability in some patients with chronic ischaemic myocardial dysfunction. The present study was designed to appraise the value of99mTc-sestamibi as a viability tracer in patients with a recent myocardial infarction and to determine factors that might influence its accuracy in assessing infarct size. Therefore, rest99mTc-sestamibi SPET, low-dose dobutamines stress echocardiography and quantitative coronary angiography were performed in 51 patients with a recent myocardial infarction. Perfusion activity and regional wall motion were scored semi-quantitatively using the same segmental division of the left ventricle. Assessment of99mTc-sestamibi uptake as a marker of viability was performed by comparing a binary uptake score (viable=〉50% vs necrotic =≤50% of the maximal tracer activity) with a binary wall motion classification during low-dose dobutamine infusion (viable=normal/hypokinetic vs necrotic=akinetic/dyskinetic). Infarct size, expressed as the number of segments with evidence of necrotic tissue, was significantly greater in the scintigraphic study than in the echocardiographic study (2.8±1.5 vs 2.2±1.3,P=0.006). This overestimation of infarct size by99mTc-sestamibi was present only in patients with a severe infarct-related stenosis (% diameter stenosis ≽65%–100%) and particularly those with “late” reperfusion therapy (time delay ≽180 min). In patients without a severe infarct-related stenosis,99mTc-sestamibi was able to accurately distinguish viable from necrotic segments. Thus, rest99mTc-sestamibi scintigraphy early after acute myocardial infarction may underestimate residual viability within the infarct region, particularly in patients with low flow state coronary anatomy, as a result of a severe infarct-related stenosis and/or late reperfusion therapy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1619-7089
    Schlagwort(e): Jeopardized myocardium ; Adenosine ; Technetium-99m sestamibi ; Stenosis severity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract This study investigated the value of technetium-99m sestarnibi scintigraphy in identifying patients at risk for post-infarct ischaemia (=jeopardized myocardium), especially within the reperfused infarct region. In 51 patients with a recent (〈I month) myocardial infarction, adenosine99mTc-sestamibi single-photon emission tomography (SPET) and dobutamine stress echocardiography (DSE) were performed and correlated with the presence of significant coronary artery stenosis [% diameter stenosis (DS) 〉50%] on quantitative coronary angiography. Regional perfusion activity was analysed semiquantitatively (score 0–4) on a 13-segment left ventricular model. DSE was used for the estimation of the infarct size (low-dose DSE) and for concomitant evaluation of ischaemia (high-dose DSE). A reversible perfusion defect within the infarct region was observed in 20 of the 37 patients with a significant infarct-related lesion (sensitivity of 54%) and only in one patient without a significant infarct-related lesion (specificity of 93%). Further analysis revealed that the scintigraphic assessment of jeopardized myocardium was fairly good in patients with a moderate (DS 51%–64%) infarct-related stenosis but was inadequate in patients with a severe (DS≥65%) infarct-related stenosis (sensitivity of 80% vs 36%,P〈0.01), while the echocardiographic detection of ischaemia was not influenced by stenosis severity (sensitivity of 73% in both subgroups). This scintigraphic under-estimation of jeopardized myocardium was mainly related to a severely impaired myocardial perfusion under baseline conditions, as was evidenced by a significantly more severe rest perfusion score in the infarct region in patients with a severe stenosis as compared to those with a moderate stenosis (average score: 1.5±0.7 vs 2.1±0.6,P〈0.01), while infarct size on echocardiography was similar for both subgroups. It may be concluded that early after an acute myocardial infarction, adenosine99mTc-sestamibi SPET may underestimate reperfused but still jeopardized myocardium, particularly in patients with a severe infarct-related stenosis. In these patients the evaluation of the ischaemic burden on rest-stress scintigraphy is hampered by the presence of a severely impaired myocardial perfusion in resting conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1619-7089
    Schlagwort(e): Key words: Jeopardized myocardium ; Adenosine ; Technetium-99m sestamibi ; Stenosis severity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. This study investigated the value of technetium-99m sestamibi scintigraphy in identifying patients at risk for post-infarct ischaemia (=jeopardized myocardium), especially within the reperfused infarct region. In 51 patients with a recent (〈1 month) myocardial infarction, adenosine 99mTc-sestamibi single-photon emission tomography (SPET) and dobutamine stress echocardiography (DSE) were performed and correlated with the presence of significant coronary artery stenosis [% diameter stenosis (DS) 〉50%] on quantitative coronary angiography. Regional perfusion activity was analysed semi-quantitatively (score 0–4) on a 13-segment left ventricular model. DSE was used for the estimation of the infarct size (low-dose DSE) and for concomitant evaluation of ischaemia (high-dose DSE). A reversible perfusion defect within the infarct region was observed in 20 of the 37 patients with a significant infarct-related lesion (sensitivity of 54%) and only in one patient without a significant infarct-related lesion (specificity of 93%). Further analysis revealed that the scintigraphic assessment of jeopardized myocardium was fairly good in patients with a moderate (DS 51%–64%) infarct-related stenosis but was inadequate in patients with a severe (DS≥65%) infarct-related stenosis (sensitivity of 80% vs 36%, P〈0.01), while the echocardiographic detection of ischaemia was not influenced by stenosis severity (sensitivity of 73% in both subgroups). This scintigraphic underestimation of jeopardized myocardium was mainly related to a severely impaired myocardial perfusion under baseline conditions, as was evidenced by a significantly more severe rest perfusion score in the infarct region in patients with a severe stenosis as compared to those with a moderate stenosis (average score: 1.5±0.7 vs 2.1±0.6, P〈0.01), while infarct size on echocardiography was similar for both subgroups. It may be concluded that early after an acute myocardial infarction, adenosine 99mTc-sestamibi SPET may underestimate reperfused but still jeopardized myocardium, particularly in patients with a severe infarct-related stenosis. In these patients the evaluation of the ischaemic burden on rest-stress scintigraphy is hampered by the presence of a severely impaired myocardial perfusion in resting conditions.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of clinical monitoring and computing 12 (1995), S. 21-24 
    ISSN: 1573-2614
    Schlagwort(e): monitoring ; physiologic ; human factors ; display ; head-up ; private eye
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Medizin
    Notizen: Abstract To solve the problem of monitoring the patient during administration of anesthesia, a commercially available headup display (HUD) was evaluated during one day of surgery at the Ohio State University Hospitals. This monitor is mounted on a headband worn by the anesthesiologist. It projects a monochrome image of monitor data directly into one eye. Eleven anesthesiologists tested the device. Most users were able to adjust to the monitor in about fifteen minutes. Nine of the testers expressed a desire to evaluate the monitor further. Their major complaints were that the connecting cable between the HUD and its computer was too short, the resolution of the monitor was inadequate, and the data on the screen were not organized in a familiar way. If these problems could be corrected, most users believed that this HUD could be a valuable tool to aid the anesthesiologist in the operating room.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of clinical monitoring and computing 14 (1998), S. 89-94 
    ISSN: 1573-2614
    Schlagwort(e): Anesthesia ; automatic ; recordkeeping ; medical records ; computers ; human factors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Medizin
    Notizen: Abstract Objective. To install and successfully use early commercial automatic anesthesia recordkeepers, the Diatek Arkive “Organizer” units, in the operating rooms at a major university medical center. Methods. Because of the history of previous academic attempts at automatic anesthesia recordkeeping, the units were installed on a “surprise” basis, with hardly any discussion of the devices beforehand. Results. The devices themselves had a number of minor difficulties at the start, most of which were promptly corrected. Eventually the units were in use in all non-cardiac general operating rooms. At one point, usage reached over 90% of possible cases. Continued opposition to the device on the part of certain individuals, coupled with the obsolescence of the present devices in light of new technology, led to the eventual abandonment of the system and removal of the devices from service. Discussion. Total resistance to the new devices on the part of a few vocal faculty members was a major factor in the ultimate downfall of the system. The method of introduction, and especially the lack of involvement of faculty, residents, surgeons, operating room personnel, hospital computer personnel, and the hospital administration in the installation also played a role in the failure of the system. Lack of a workable training mechanism for new residents prevented that user group from rapidly gaining comfort with the systems.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Journal of clinical monitoring and computing 16 (2000), S. 541-546 
    ISSN: 1573-2614
    Schlagwort(e): Alarms ; alarm sounds ; human factors ; medical devices ; monitoring ; medical ; music ; standardization ; national standards ; international standards
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of clinical monitoring and computing 15 (1999), S. 57-61 
    ISSN: 1573-2614
    Schlagwort(e): Equipment ; monitoring ; anesthesia, inhalational ; anesthetics, volatile ; halothane ; enflurane ; isoflurane ; vaporizer ; key-filling systems ; mixture ; errors ; human factors
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Informatik , Medizin
    Notizen: Abstract The creation of agent mixtures from the addition of the wrong agent to a vaporizer might pose a risk to the patient. Patient injury would be more likely if the anesthesia gas monitor displayed erroneous concentration values. Conventional inhalation agent monitors do not necessarily distinguish anesthetic agents. Some modern monitors have that ability but its clinical significance has not been determined. We wanted to simulate such an erroneous mixture in a laboratory setup. Six comparisons were made. Isoflurane, Enflurane, and Halothane vaporizers were first filled with the correct agent. They were run at 5 liters/minute fresh oxygen flow at a vaporizer dial setting of 5% until it reached the “refill” line. Then, one of two incorrect agents was added to the “full” line. Thereafter, the vaporizer continued at the same flow and the same dial setting until it was exhausted. Vaporizer output was recorded or calculated by using three methods of measurement: mass spectrometry, conventional infrared analysis (at 3.3 micrometer wave length), and piezoelectric crystal analysis. Additional calculations were used to estimate measurements that could not be made because of lack of available equipment. In a Halothane vaporizer: Enflurane added – not a significant problem; Isoflurane added – not a significant problem. In an Isoflurane vaporizer: Halothane added – not a significant problem; Enflurane added – not a significant problem. In an Enflurane vaporizer: Isoflurane added – not a significant problem; Halothane added – The sum of the delivered Halothane MAC and the delivered Enflurane MAC was twice the expected Enflurane MAC output from vaporizer, with conventional agent monitor reading which showed decreasing agent concentration. Patient injury could be more likely in this last case. In this last case and in all cases, piezoelectric crystal monitoring correctly displayed the sum of the two agent concentrations in volumes percent. Automatic agent identification can identify erroneous agents.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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