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| 3. |
- Jensen, Steen, et al.
(författare)
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On-line computerized vectorcardiography monitoring of myocardial ischemia during coronary angioplasty : comparison with 12-lead electrocardiography
- 1994
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Ingår i: Coron Artery Dis. ; 5:6, s. 507-14
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: With new interventions minimizing ischemic myocardial injury, accurate and reliable techniques for the detection and continuous monitoring of myocardial ischemia are essential. We compared two techniques used for the detection of myocardial ischemia during coronary angioplasty: on-line computerized vectorcardiographic (cVCG) monitoring and the standard electrocardiography (ECG) leads or the complete 12-lead ECG. METHODS: Thirty patients scheduled for routine angioplasty were included in the study. cVCG was recorded continuously. The electrodes were placed according to the lead system described by Frank and connected to a computerized system for on-line vectorcardiography. A 12-lead ECG was recorded simultaneously. The absolute variable spatial ST vector magnitude (ST-VM) and the relative variable spatial ST change vector magnitude (STC-VM) were calculated and compared with the standard 12-lead ECG for the detection of ischemia. RESULTS: The sum of deviation in ST segment in all 12 standard ECG leads correlated closely with STC-VM, irrespective of which artery was occluded. STC-VM indicated ischemia during the first balloon inflation in 87% of the patients and demonstrated ischemia in more patients than the standard 12-lead ECG. Myocardial ischemia was not demonstrated by ST-VM in five out of 26 patients with ischemia according to STC-VM. In these cases, mainly directional vector changes and fewer changes in magnitude were observed. CONCLUSION: Compared with 12-lead ECG, on-line cVCG is a more sensitive method of detecting myocardial ischemia during coronary angioplasty and the reading is easier and faster. Our results support STC-VM > or = 0.050 mV as the criterion for ischemia during angioplasty; ST-VM should be applied together with STC-VM.
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| 4. |
- Ahrne, Göran, et al.
(författare)
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Between Organizations
- 1994
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Ingår i: Social organizations. - London : Sage Publications. - 0803989202
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Akselsson, Roland, et al.
(författare)
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Fysikaliska faktorer
- 1994
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Ingår i: Arbete Människa Teknik. - 9175224143 ; , s. 45-113
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Edin, Benoni B, et al.
(författare)
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Independent control of human finger-tip forces at individual digits during precision lifting.
- 1992
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Ingår i: Journal of Physiology. - 0022-3751 .- 1469-7793. ; 450, s. 547-64
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Tidskriftsartikel (refereegranskat)abstract
- 1. Subjects lifted an object with two parallel vertical grip surfaces and a low centre of gravity using the precision grip between the tips of the thumb and index finger. The friction between the object and the digits was varied independently at each digit by changing the contact surfaces between lifts. 2. With equal frictional conditions at the two grip surfaces, the finger-tip forces were about equal at the two digits, i.e. similar vertical lifting forces and grip forces were used. With different frictions, the digit touching the most slippery surface exerted less vertical lifting force than the digit in contact with the rougher surface. Thus, the safety margins against slips were similar at the two digits whether they made contact with surfaces of similar or different friction. 3. During digital nerve block, large and variable safety margins were employed, i.e. the finger-tip forces did not reflect the surface conditions. Slips occurred more frequently than under normal conditions (14% of all trials with nerve block, <5% during normal conditions), and they only occasionally elicited compensatory adjustments of the finger-tip forces and then at prolonged latencies. 4. The partitioning of the vertical lifting force between the digits was thus dependent on digital afferent inputs and resulted from active automatic regulation and not just from the mechanics of the task. 5. The safety margin employed at a particular digit was mainly determined by the frictional conditions encountered by the digit, and to a lesser degree by the surface condition at the same digit in the previous lift (anticipatory control), but was barely influenced by the surface condition at the other digit. 6. It was concluded that the finger-tip forces were independently controlled for each digit according to a 'non-slip strategy'. The findings suggest that the force distribution among the digits represents a digit-specific lower-level neural control establishing a stable grasp. This control relies on digit-specific afferent inputs and somatosensory memory information. It is apparently subordinated to a higher-level control that is related to the total vertical lifting and normal forces required by the lifting task and the relevant physical properties of the manipulated object.
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| 8. |
- Hamberg, Katarina, et al.
(författare)
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Scientific rigor in qualitative research : examples from a study of women´s health
- 1994
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Ingår i: Family Practice. - : Oxford University Press. - 0263-2136 .- 1460-2229. ; 11, s. 176-181
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Tidskriftsartikel (refereegranskat)abstract
- The increase in qualitative research in family medicine raises a demand for critical discussions about design, methods and conclusions. This article shows how scientific claims for truthful findings and neutrality can be assessed. Established concepts such as validity, reliability, objectivity and generalization cannot be used in qualitative research. Alternative criteria for scientific rigour, initially introduced by Lincoln and Guba, are presented: credibility, dependability, confirmability and transferability. These criteria have been applied to a research project, a qualitative study with in-depth interviews with female patients suffering from chronic pain in the locomotor system. The interview data were analysed on the basis of grounded theory. The proposed indicators for scientific rigour were shown to be useful when applied to the research project. Several examples are given. Difficulties in the use of the alternative criteria are also discussed.
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| 9. |
- Hohner, Per, et al.
(författare)
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Anaesthesia for abdominal vascular surgery in patients with coronary artery disease (CAD), Part I : Isoflurane produces dose-dependent coronary vasodilation
- 1994
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Ingår i: Acta Anaesthesiol Scand. ; 38:8, s. 780-92
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Tidskriftsartikel (refereegranskat)abstract
- The effects of anaesthesia for major abdominal vascular surgery on coronary flow regulation and mechanisms of myocardial ischaemia were studied in 56 patients with CAD, using a randomized, partly double-blinded protocol. After induction with fentanyl (3 micrograms.kg-1) and thiopentone (2-4 mg.kg-1) and tracheal intubation, principal anaesthetics were nitrous oxide/oxygen (60/40) with isoflurane (n = 20), halothane (n = 19) or fentanyl (15-20 micrograms.kg-1) (n = 17). Conventional invasive techniques and coronary venous retrograde thermodilution were used to assess systemic and coronary haemodynamics. Coronary vascular resistance was estimated from myocardial oxygen extraction. Myocardial ischaemia was diagnosed by 12-lead ECG and/or anterior wall motion abnormalities by cardiokymography and/or myocardial lactate production. When adjustment of anaesthetic dose was insufficient for haemodynamic control, i.v. phenylephrine and nitroglycerine were administered to treat hypotension and hypertension or cardiac failure respectively. Measurements were performed at four specific intervals; awake, before surgery and 10 and 30 min after abdominal incision. Comparable changes of systemic haemodynamics and myocardial oxygen consumption were observed in the three groups. Coronary vasodilation was evidenced in isoflurane patients only and was linearly dose-dependent (P < 0.001). Partial Least Squares Projections to Latent Structures modelling with cross validation confirmed this dose-dependency and ruled out a clinically measurable influence by intervention drugs or simultaneous systemic haemodynamic abnormalities. The incidence of myocardial ischaemia during anaesthesia and surgery was comparable in the three groups (35, 37 and 24%, respectively) and there was an association with systemic haemodynamic aberrations in 19 of the 27 ischaemic episodes. In contrast to ischaemic halothane and fentanyl patients, isoflurane patients with ischaemia had significantly lower myocardial oxygen extraction (P = 0.008 and P = 0.001, respectively), indicating that the oxygen extraction reserve was not utilized in a normal way during ischaemia.
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| 10. |
- Johannesson, Magnus, et al.
(författare)
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Willingness to pay for antihypertensive therapy - further results
- 1993
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Ingår i: Journal of health economics. - 1879-1646 .- 0167-6296. ; 12:1, s. 95-108
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Tidskriftsartikel (refereegranskat)abstract
- A measurement experiment regarding willingness to pay for antihypertensive therapy is reported. A new type of binary willingness to pay question is used, that allows for different degrees of certainty with respect to the responses. Mean willingness to pay is derived from a simple expected utility model and estimated using maximum likelihood methods. The estimated parameters are highly significant, with predicted signs, and imply a mean willingness to pay of about SEK 800 ($130) per month. The explanatory power of the equation that only includes 'certain' yes/no responses is, as expected, much higher than that of the equation where only 'uncertain' responses are included.
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