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Biomedical subjects

T Steen

Publications and source records attributed to T Steen.

At least 19 recordsLinked to original sources
PubMed2004

Ibuprofen vs. acetaminophen vs. ibuprofen and acetaminophen after arthroscopically assisted anterior cruciate ligament reconstruction.

BACKGROUND AND OBJECTIVE: The analgesic potency of non-steroidal anti-inflammatory drugs and acetaminophen are still being debated. We have assessed the relative analgesic effect of ibuprofen, acetaminophen or the combination of both after orthopaedic surgery. METHODS: Sixty-one ASA I patients, scheduled for an elective anterior cruciate ligament reconstruction under general anaesthesia were randomized, in a double blind fashion, into one of three groups. The ibuprofen group (n = 17) received ibuprofen 800 mg orally 1 h before operation and again at 6 and 12 h after the initial dose. The acetaminophen group (n = 20) received of acetaminophen 1 g orally at the same time intervals. The combination group (n = 24) received both ibuprofen 800 mg and acetaminophen 1 g. Surgery was performed under general anaesthesia with propofol and fentanyl for induction and maintenance with propofol and nitrous oxide in oxygen. The patients were monitored for 24 h thereafter, and the following variables were assessed: pain by visual analogue and verbal scales, need for rescue intravenous opioid analgesia (i.e. ketobemidone) and adverse events. RESULTS: The ibuprofen group and the combination group experienced significantly less pain during the first 6 h after surgery than the acetaminophen group using the visual analogue and the verbal scales. The acetaminophen group also had a significantly higher average consumption of opioids during the first 6 and 24 h. There were no significant differences between the ibuprofen group and the combination group in respect of experienced pain or consumption of rescue analgesia. The incidence of side-effects, postoperative haemoglobin concentration and renal function, judged by creatinine clearance, were identical between the groups. CONCLUSION: Ibuprofen 800 mg thrice daily reduced pain to a greater degree than acetaminophen 1 g thrice daily, after anterior cruciate ligament reconstruction under general anaesthesia. The combination of acetaminophen and ibuprofen did not provide any superior analgesic effect.

Acetaminophen↗
PubMed2002

High-dose diclofenac for postoperative analgesia after elective caesarean section in regional anaesthesia.

Although the use of non-steroidal anti-inflammatory drugs (NSAIDs) is well established in the postoperative setting, their use after caesarean sections is still controversial. In a randomised, double-blinded, placebo controlled study we have estimated the opioid-sparing effect of diclofenac suppositories after elective caesarean sections in spinal anaesthesia. Eighty-two women ASA class I or II scheduled for caesarean section were randomised to receive either diclofenac suppositories 100 mg or placebo every 12 h after the operation. The diclofenac group (n = 40) consumed significantly less morphine in the postoperative period (14.0 +/- 1.5 mg in 32 h) compared with the placebo group (21.5 +/- 1.6 mg in 32 h, P < 0.05). The average level of postoperative pain as estimated by a visual analogue scale (VAS) and a verbal scale tended to be lower in the diclofenac group, but this was not significant. There were no differences in demographic data, perioperative bleeding, side-effects or discharge time between the groups. Diclofenac suppositories 100 mg given twice daily after caesarean section are opioid sparing.

Clinical Trial↗
PubMed2002

The use of cognitive methods in analyzing clinicians' task behavior.

To ensure the acceptance and routine use of information systems in healthcare tight coupling is required between the work practices of potential endusers and the systems functionalities and presentation of these functionalities via the user interface. The application of methods from cognitive engineering during requirement analysis may contribute to the support of healthcare work practice by computer systems. We applied the think aloud method in combination with video analysis during the requirement analysis phase in designing a user interface for a patient information retrieval system. These methods provided a detailed insight in the information needs of physicians and the way in which they search through this information in preparing a patient visit. Using these insights in endusers work practices in the early phase of user interface development may lead to a better fit between physicians' work practices and the supporting computer system.

Ambulatory Care Facilities↗
PubMed2002

Cognitive engineering in interface design.

Today, many medical information systems are not satisfactory to their users. To ensure ultimate acceptance of health care information systems asks for systems that map on health care workers' tasks and on their cognitive processes in performing these tasks. The development of human-oriented computer interfaces requires insight in users' information needs and information processing in view of the tasks that will be computer-supported. Cognitive engineering aims at understanding the fundamental principles behind human activities that are relevant in designing a system that supports these activities. The application of cognitive engineering methods may therefore contribute to computer systems that fit better in health care working practices. We used cognitive engineering methods in designing a user interface for a physicians' workstation to support them in preparing their patient screening. The information needs and information search strategies of 4 physicians were revealed by systematic analyses of verbal protocols and video's while they successively worked through 10 paper-based patient records in preparing their patient visits. The results of these analyses were used as input for the design of a conceptual higher-order model that represents both the information needs and information search strategy of these physicians. Based on this higher-order conceptual model, we developed paper-mock ups and a first prototype of the user interface. The physicians will evaluate this prototype in the next phase of the project.

Cognition↗
PubMed2000

[Are physicians' examinations required for driving licences correct?].

73 consecutive medical certificates for granting driving licenses were examined. The certificates were given on standard forms with yes/no tick boxes. They were used by the Norwegian Board of Health in handling appeals against rejected applications for exemption from the health requirements for driving licenses. Two of the 73 certificates contained incorrect statements about the applicants' medical conditions. A further two were incomplete with regard to medical facts known to the issuing physician, whereas the remaining 69 certificates gave correct information about the health of the applicant. The conclusion as to whether the applicant fulfilled the health requirements was correctly stated in 30 certificates (41%). 22 certificates (30%) wrongly concluded that the requirements were met, and 21 (29%) lacked a conclusion. The health requirements are printed on the certificate form along with a note to remind the physician to adhere to them. We conclude that even in official medical certificates with yes/no tick boxes, physicians may be reluctant to give conclusions they understand will not benefit their patients.

Automobile Driver Examination↗
PubMed2000

Does ketamine have preemptive effects in women undergoing abdominal hysterectomy procedures?

UNLABELLED: Ketamine may produce "preemptive" analgesia when administered before surgically induced trauma. Therefore, we hypothesized that pre- versus postincisional administration of ketamine would improve pain control after abdominal hysterectomy procedures. Eighty-nine patients were randomly assigned to one of three treatment groups according to a placebo-controlled, double-blinded protocol: Group 1 (placebo) received saline 0.04 mL/kg IV immediately before and after surgery; Group 2 (preincision), received ketamine 0.4 mg/kg IV before skin incision and saline at the end of the operation; and Group 3 (postincision), received saline before skin incision, and ketamine 0.4 mg/kg IV was given after skin closure. The general anesthetic technique was standardized in all three treatment groups. During the first postoperative hour, Group 3 experienced significantly less pain than Groups 1 and 2, as assessed by using both visual analog and verbal rating scales. There were no significant differences between Groups 1 and 2 with respect to pain scores, postoperative opioid analgesic requirements, and incidence of postoperative nausea and vomiting. We conclude that a single dose of ketamine 0.4 mg/kg IV fails to produce preemptive analgesic effects. IMPLICATIONS: Even though ketamine 0.4 mg/kg IV has short-lasting acute analgesic effects, it failed to produce a preemptive effect when given before abdominal hysterectomy procedures.

Adult↗
PubMed1997

Temperature guided radiofrequency catheter ablation of myocardium: comparison of catheter tip and tissue temperatures in vitro.

Temperature monitoring during RF ablation has been proposed as a means of controlling the creation of the lesion. However, in vivo studies have shown poor correlation between lesion size and catheter tip temperature. Thus, we hypothesized a difference between catheter tip and tissue temperatures during RF catheter ablation, and that this difference may depend on flow passing the ablation site, tip electrode length, and catheter-tissue orientation. In vitro studies were performed using four different ablation catheters (tip electrode length: 2, 4, or 6 mm) with a thermistor or a thermocouple as temperature sensor. Set temperature was 70 degrees C and pulse duration was 30 seconds. Pieces of porcine left ventricle were immersed in a bath of isotonic saline-dextrose solution at 37 degrees C. The ablation catheters were positioned perpendicularly, obliquely, or parallel to the endocardium. A temperature sensor was inserted from the epicardial side and positioned 1 mm beneath the catheter-tissue interface. Experiments were made with a flow of 200 mL/min passing the ablation site or with no flow. The catheter tip and tissue temperatures differed significantly (P < 0.0001) during ablation. This difference increased with time, with flow passing the ablation site, with the length of the tip electrode, and when the catheter was positioned perpendicularly or obliquely to the endocardium as compared to the parallel catheter-tissue orientation (P < 0.05). In conclusion, the tissue temperature may far exceed the catheter tip temperature, and intramyocardial superheating resulting in steam formation and popping may occur despite a relatively low catheter tip temperature.

Animals↗
PubMed1996

[Health hazards when using snuff].

Snuff taking produces a white to yellowish, wrinkled lesion of the oral mucosa at the site where the quid is placed. The lesion is reversible, and only rarely exhibits dysplasia. Gingival recession and loss of attachment may occur in conjunction with the mucosal lesion. The risk of oral cancer varies greatly among the different published studies, from a relative risk of 48 to no increase in risk at all. Case control studies have found no association between oral tobacco and bladder cancer, whereas cigarette smoking carries a relative risk of about two. There appears to be no evidence for an association between oral snuff and cancer in general when the analysis takes into account confounders such as occupation, smoking and alcohol. The epidemiological evidence for an association with cardiovascular disease is contradictory. Snuff may probably cause hypertension, and one large study has reported a relative risk of 2 for dying of ischaemic heart disease. Biochemical evidence disfavors the hypothesis that snuff is atherogenic. In conclusion, the health hazards of oral moist snuff seem modest, and very much smaller than those of cigarette smoking.

Gingiva↗
PubMed1995

A new color M-mode index of diastolic filling compared with radionuclide ventriculography.

We correlated the new diastolic index 'delay of apical peak velocity', as measured by colour M-mode Doppler, with radionuclide ventriculographic indices of ventricular function. Thirty-seven patients with coronary artery disease participated in the prospective and blinded study, which included repeated acquisitions to determine the effect of realigning the Doppler sample beam. In multiple regression, neither peak filling rate, left ventricular phase histogram width nor ejection fraction were statistically significantly related to delay of apical peak velocity. The standard deviation of the differences between duplicate colour M-mode acquisitions corresponded to half the reference range of the index. We conclude that in this blinded investigation, the new Doppler index did not provide information about ventricular function equivalent to radionuclide ventriculography. The index may be significantly influenced by sample beam position.

Aged↗
PubMed1995

Reproducibility of the 14C urea breath test repeated after 1 week.

OBJECTIVES: The aim of this study was to determine the numerical and categorical reproducibility of the 14C urea breath test in a routine clinical setting. BACKGROUND: The 14C urea breath test is used for diagnosis of Helicobacter pylori infection and is regarded by some centers as the gold standard. METHODS: In 140 referrals, duplicate tests were performed 1 wk apart. Eighteen patients were excluded because they had taken antibiotics or had changed medication that could influence the gastric urease activity between the tests. RESULTS: The limits of agreement between the repeated tests were 45-234%. Hence, the numerical result of a repeated test was 95% likely to differ from the first with a factor of approximately two or less. However, when patients were classified as "positive" or "negative" according to our previously determined cut-off limit, only three patients were discordantly classified by the two tests. The observed agreement between the tests was 98%, and the chance-corrected proportional agreement (kappa) was 95%, which is far better than that reported for the histological diagnosis of gastric H. pylori infection. CONCLUSION: The diagnostic reproducibility of the urea breath test was very good.

Adolescent↗
PubMed1994

Visual assessment of intra ventricular flow from colour M-mode Doppler images.

Left intra ventricular filling was studied by colour M-mode Doppler ultrasound to determine whether the flow pattern can be assessed visually, and explore its relation to left ventricular (LV) function. Patients with coronary artery disease (CAD) or dilated cardiomyopathy (DCM) were divided into three groups according to angiographically evaluated LV function. The groups were compared with a control group of 54 healthy volunteers. The mitral to apical delay of early diastolic flow was qualitatively assessed from printed colour M-mode images, twice by four independent observers blinded to the subject's status. The repeatability of the assessments as determined by the kappa statistic was good intra observer (kappa = 0.75) and moderate inter observer (kappa = 0.53). The CAD-group with angiographically normal LV function (n = 25) had flow patterns resembling those observed in the control group. The group with ejection fraction (EF) < 50% (n = 19) had flow patterns clearly different from the control group. Patients with regional wall motion abnormality (RWMA) but EF > 50% (n = 16) exhibited flow patterns intermediate between the control and the low EF group. Among the 50 CAD patients there was a negative correlation between EF and the presence of delay of apical peak velocity (Spearman's rs = -0.62, p < 0.0001). A visible delay of apical peak velocity had a sensitivity towards DCM of 83% and specificity of 75%. The sensitivity towards CAD with either RWMA or low EF was 55% and the specificity 75%. In conclusion, visual assessment of intra ventricular flow patterns was feasible and allowed discrimination between normal and diseased ventricles.

Adult↗
PubMed1994

Repeatability of colour M-mode Doppler measurements of left ventricular filling.

We investigated the repeatability of two recently reported colour M-mode Doppler measures of left ventricular diastolic function. 'Delay of peak velocity' is the time interval from peak velocity of early filling at the mitral tip level to peak velocity in the apical region. The 'velocity of flow propagation' is the speed of the mitral to apical spread of the early diastolic filling. Two examiners independently and blindly made measurements by both methods on 32 digital recordings twice, using custom software. Inter- and intra-observer repeatability were given in terms of limits of agreement, where 1 denotes perfect agreement. Limits of intra-observer agreement were 0.72-1.43 for measurements of 'delay of peak velocity', and 0.39-2.28 for 'velocity of flow propagation'. Limits of inter-observer agreement were 0.68-1.42 and 0.19-2.04 respectively. The correlation between the methods was weak (r = 0.45), suggesting that they may detect different properties of early diastole. We suggest that the reliability of the methods may be improved by replicate measurements performed blindly. There are reasons to express the velocity of flow propagation on a logarithmic scale.

Echocardiography, Doppler↗
PubMed1994

Repeatability of measurements of pulmonary venous flow indices.

We investigated the measurement repeatability of four pulmonary venous flow indices. The indices were measured on 45 anonymised, transthoracic Doppler recordings of adequate technical quality. Measurements were taken by two independent observers, and repeated after 10 days. Plus/minus the repeatability coefficient, which was used to quantify repeatability, gives the 95% probability limits for random variation between repeated measurements. The index D-diff, which is the difference in duration of the pulmonary venous flow reversal during atrial systole and the transmitral A-wave, had repeatability coefficients of 50 and 57 ms intra- and inter-observer. For the fraction of antegrade pulmonary venous flow during ventricular systole, the coefficients were 12 and 13 percentage points, but improved to 6 and 7 among the high-quality recordings. The retrograde pulmonary venous flow during atrial systole as a fraction of the antegrade flow, had coefficients of 5 percentage points both intra- and inter-observer. The coefficient for the peak velocity of retrograde pulmonary venous flow was 0.05 m/s intra- and inter-observer. Thus, the systolic fraction was the only index that showed a satisfactory repeatability. We suggest that if the other indices are used, measurements should be taken by a blinded observer to avoid observer bias.

Analysis of Variance↗
PubMed1994

Filling of a model left ventricle studied by colour M mode Doppler.

OBJECTIVE: It has been proposed that the early diastolic flow pattern inside the left ventricle reflects ventricular diastolic function. The flow pattern often divides into two phases towards the apex. The aim of this study was to examine the hydrodynamic nature of this phenomenon. METHODS: A rubber balloon representing the ventricle was connected to a reservoir representing the atrium, both filled with anticoagulated blood. Rigid "mitral" orifices 20 mm long and 15-40 mm in diameter were used. Surrounding the ventricle was a water filled chamber to which suction could be applied. The colour M mode Doppler sample beam coincided with the ventricular long axis. Colour M mode measures velocity at multiple sites along the beam simultaneously. The timing and magnitude of the velocities were analysed digitally. The filling was also qualitatively studied by ultrasonic two dimensional sector scanning. RESULTS: At the start of the filling, blood moved simultaneously at all levels, behaving as a fluid column. This was denoted "phase I". A flow wave then propagated from the mitral orifice towards the apex, called "phase II". This was found to represent a ring vortex, with blood velocities twice its propagation velocity [ratio 2.1(SEM 0.016)]. The ratio between the velocity time integrals of phase II and phase I decreased progressively from 51(15) to 0.41(0.14) when mitral orifice diameter was increased in 5 mm steps from 15 mm to 40 mm (p < 0.001). The propagation velocity correlated strongly with peak transmitral blood velocity, r = 0.95, p < 0.001. The flow patterns resembled patterns recorded in patients. CONCLUSIONS: The two phases of the filling pattern represented the motion of a blood column and the propagation of a ring vortex, respectively. Mitral orifice size determined which phase dominated the flow pattern.

Animals↗
PubMed1994

Influence of heart rate and left atrial pressure on pulmonary venous flow pattern in dogs.

In six open-chest anesthetized dogs we investigated the effect of heart rate (HR) on the relationship between left atrial pressure (LAP) and pulmonary venous flow (QPV). QPV was measured by ultrasonic transit time during volume loading and right atrial pacing. Consistent with previous studies, we found a negative correlation between LAP and mean flow rate during atrial systole divided by mean flow rate in the R-R interval. However, this relationship was shifted upward by tachycardia. The QPV maximum amplitude divided by mean flow rate in the R-R interval increased with loading but decreased with tachycardia. mean flow rate during ventricular systole divided by mean flow rate during the R-R interval increased with both loading and tachycardia. Regression coefficients for HR and LAP as predictors of these indexes were all significantly different from zero (P = 0.0001). We conclude that HR significantly influences the relationship between the QPV pattern and LAP. This could be a limitation of the pulmonary venous flow pattern as an indicator of left ventricular diastolic function.

Animals↗
PubMed1993

[Atrial fibrillation during pregnancy].

Atrial fibrillation in pregnancy is rare and, when encountered, appears mainly as a secondary phenomenon to congenital or valvular heart disease. Increased risk of thromboembolism or detrimental influence on the foetus makes rapid treatment essential. Conventional treatment with digitalis glycosides, verapamil and beta-blockers is safe, as shown in a 32 year-old pregnant woman without known heart disease. Synchronized direct current countershock also appears to be safe in cases resistant to drug therapy.

Adult↗