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Results for “Measurement”

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At least 217 records · Page 12Linked to original sources

PubMed1994

Measurement of respiratory mechanics in a mechanically ventilated infant lung simulator: effects of variations in the frequency response of the flow measurement system.

The frequency responses of systems used to measure flow and pressure in ventilated infants may differ, and hence affect estimates of resistance and compliance. We estimated resistance and compliance in 16 ventilated mechanical lung models using linear regression while varying the frequency response of the flow measurement system. Lung models comprised combinations of four sections of tubing and four bottles filled with steel wool. The cut-off frequencies of a filter in the flow measurement system were chosen to yield time delays of 0, +/-3, +/-6, and +/-9 ms relative to the pressure signal. When the phase lags in the measurement systems were not equal at 10 Hz, a bias in resistance approximately (relative delay) x (elastance) ensued. The bias in the resistance estimate when resistance is 5 Pa ml-1 s and compliance is 2 ml kPa-1 is approximately 28% per ms of delay mismatch. Time-shifting the flow data to eliminate the phase discrepancy reduced the resistance bias by 85%. The residual resistance bias was assumed to be due to inappropriate amplitude response. Compliance measurements were affected by less than 8% and less than 2% after time correction of the flow data. Pressure and flow signals must be synchronized to within 1 ms at 10 Hz and the amplitude responses of the measurement systems must be adequate for reliable resistance measurement.

Adult↗

PubMed2000

Screening for osteoporosis using easily obtainable biometrical data: diagnostic accuracy of measured, self-reported and recalled BMI, and related costs of bone mineral density measurements.

The aims of the present study were: to determine the diagnostic accuracy of objectively measured, self-reported and recalled body mass index (BMI) for osteoporosis and osteopenia; to determine the diagnostic costs, in terms of bone mineral density (BMD) measurements, per osteoporotic or osteopenic patient detected, using different BMI tests; and to determine the extent to which the results can be used within the framework of the current screening program for breast cancer in The Netherlands. Within the framework of a cross-sectional study on the prevalence of osteoporosis in the south of The Netherlands, 1155 postmenopausal women aged 50-80 years were asked for their present height and their weight at age 20-30 years. Subsequently their actual weight, height and BMD of the lumbar spine (DXA) were measured. The BMD cutoff was 0.800 g/cm2 for osteoporosis and 0.970 g/cm2 for low BMD (osteoporosis + osteopenia). After receiver operating characteristic analysis, age was cut off at 60 years and BMI at 27 kg/m2. Diagnostic accuracies of objectively measured, self-reported and recalled BMI were evaluated using predictive values (PV) and odds ratios. The resulting 'true positive' and 'false positive' rates were used to calculate diagnostic costs (i.e., DXA) for each osteoporotic patient or low-BMD patient detected. The prevalence of osteoporosis in the study population was 25%, that of low BMD 65%. Only the age-BMI tests 'age > or = 60, BMI < or = 27' showed PVs for osteoporosis (31-41%) and for low BMD (71-81%) that were higher than the prior probabilities for these conditions. Related odds ratios were 2.14-3.18 (osteoporosis) and 1.87-3.04 (low BMD). The objective BMI test detected 50% of the osteoporotic patients. Using the self-reported BMI test and the recalled BMI test, detection rates increased to 55% and 69%, respectively. Concomitant costs per osteoporotic patient detected rose by 24%. Detection of patients with a low BMD increased from 38% for objective BMI and 42% for self-reported BMI to 60% for recalled BMI. Related costs increased by 11%. If all women over 50 years of age (irrespective of their BMI) were to be referred for BMD measurement, costs per osteoporotic patient or low-BMD patient detected would be 304 and 116 Euros, respectively. Only in women over 60 years does a BMI below 27 kg/m2 provide a better prediction of the presence of osteoporosis or low BMD than could be expected solely on the basis of the relevant prevalences in postmenopausal women aged 50-80 years. If the use of BMI for the detection of osteoporotic or low-BMD patients is still considered, measuring weight and just asking for a person's height will do. Although age and BMI are the strongest risk factors for osteoporosis, they are of less significance when used for screening the population for osteoporosis. More research is needed before age and BMI can be included in any screening program. As regards practical considerations alone, measurements of BMD could be implemented within the screening program for breast cancer.

Absorptiometry, Photon↗

PubMed2001

Routine measurements of left and right ventricular output by gated blood pool emission tomography in comparison with thermodilution measurements: a preliminary study.

The aim of this preliminary study was to evaluate the accuracy of left and right ventricular output computed from a semi-automatic processing of tomographic radionuclide ventriculography data (TRVG) in comparison with the conventional thermodilution method. Twenty patients with various heart diseases were prospectively included in the study. Thermodilution and TRVG acquisitions were carried out on the same day for all patients. Analysis of gated blood pool slices was performed using a watershed-based segmentation algorithm. Right and left ventricular output measured by TRVG correlated well with the measurements obtained with thermodilution (r = 0.94 and 0.91 with SEE = 0.38 and 0.46 l/min, respectively, P < 0.001). The limits of agreement for TRVG and thermodilution measurements were -0.78-1.20 l/min for the left ventricle and -0.34-1.16 l/min for the right ventricle. No significant difference was found between the results of TRVG and thermodilution with respect to left ventricular output (P = 0.09). A small but significant difference was found between right ventricular output measured by TRVG and both left ventricular output measured by TRVG (mean difference = 0.17 l/min, P = 0.04) and thermodilution-derived cardiac output (mean difference = 0.41 l/min, P = 0.0001). It is concluded that the watershed-based semi-automatic segmentation of TRVG slices provides non-invasive measurements of right and left ventricular output and stroke volumes at equilibrium, in routine clinical settings. Further studies are necessary to check whether the accuracy of these measurements is good enough to permit correct assessment of intracardiac shunts.

Adult↗

PubMed2002

Isometric strength measurement for muscle weakness in cancer patients: reproducibility of isometric muscle strength measurements with a hand-held pull-gauge dynamometer in cancer patients.

Our aim was to determine several indexes of reproducibility for strength measurements with a hand-held pull-gauge dynamometer (MFB50K) in cancer patients. Two independent testers performed repeated measurements of maximal isometric elbow and knee strength. The measurements were gathered in a convenience sample of 40 patients (27 men, age 20-72 years) with various types and stages of cancer. These patients were recruited from the medical oncology clinic of a university hospital. The Pearson product moment correlation coefficient, the intraclass correlation coefficient (ICC), the standard error of measurement (SEM) and its associated 95% confidence interval, the smallest detectable difference (SDD) and the limits of agreement were determined as outcome measures for reproducibility. The results for the Pearson product moment correlation and the ICC were 0.90 for elbow and 0.96 for knee extension strength. The results in terms of the SDDs were 29.4 newton (N) for elbow and 54.8 N for knee strength. The limits of agreement for elbow strength were -21.7 N and 38.5 N (mean 8.4 N). For knee strength the limits of agreement were -49.8 N and 59.8 N (mean 5 N). The Pearson product moment correlation and the ICC suggested good reproducibility. However, the more informative indices of reproducibility, i.e. the SEM and the SDD, showed relatively large measurement error between the testers. Therefore, the current use of the MFB50K for the measurement of muscle strength is not supported in cancer patients.

Adult↗

PubMed2006

Measuring health-related quality of life in bipolar disorder: relationship of the EuroQol (EQ-5D) to condition-specific measures.

UNLABELLED: Generic utility measures of health-related quality of life provide an independent net valuation of health states. They are increasingly used with condition-specific outcome measures in assessing treatments. In Bipolar Disorder, a few studies indicate poorer quality of life for depressed vs. euthymic patients. A single study suggests mania is less negative than depression. This analysis examines the relationship of one such scale, the EuroQol (EQ-5D), to objective and subjective measures of depression and mania in 221 Bipolar subjects, recently or still in an episode of illness. RESULTS: Depressed patients showed a very poor quality of life (median EQ-5D Index score 0.41). Index and Visual Analogue scores improved significantly as level of depression decreased (Jonckheere-Terpstra test p<0.001). Both scores were significantly negatively related to all depression measures. Patients reported problems across all areas of life covered by the EQ-5D. No such relationships were observed between EQ-5D scores and mania measures, though all mania measures were inter-related. However, the range of mania shown was quite restricted. CONCLUSIONS: The EQ-5D is a useful measure of quality of life for Bipolar patients suffering from depression. Conclusions about the role of the EQ-5D in mania are restricted by the limited range of mania observed.

Adult↗

PubMed1989

Measurement of left ventricular ejection fraction and volumes with three-dimensional reconstructed transesophageal ultrasound scans: comparison to radionuclide and thermal dilution measurements.

A transesophageal, ultrasonic cardiac imaging probe was built that incorporated a mechanism for changing the angle of the imaging plane of a conventional phased array in a precise and known manner. This probe was used to acquire an angular spatial sequence of two-dimensional images of the left ventricular cavity over a series of cardiac cycles by sweeping the imaging plane through it stepwise. The endocardial borders of these images were manually outlined off-line and the application of a three-dimensional reconstruction algorithm was then used to compute the left ventricular end-diastolic and end-systolic volumes and ejection fraction. A study was conducted with seven anesthesized dogs to compare ultrasonic determinations by this method with determinations and measurements made using radionuclide and thermal dilution methods. Comparison of 33 ejection fractions, measured by the ultrasonic volume method and by the gated blood pool radionuclide approach, yielded a correlation coefficient of 0.87 and a standard error of the estimate of 5.7% measured over a range of 10% to 58% (average, 40%). Comparison of the ultrasonically measured volumes with those calculated from stroke volume (derived from thermal dilution cardiac output measurement) and ejection fraction (measured by radionuclide technique) produced a correlation coefficient of 0.92 and a standard error of the estimate of 10.3 mL over a range of 18 to 130 mL (average, 56 mL). The accuracy of volume and ejection fraction measurements with this new ultrasonic method seems comparable to that of other currently used clinical approaches such as radionuclide and angiography.

Animals↗

PubMed2005

Carotid stenosis measurement on colour Doppler ultrasound: agreement of ECST, NASCET and CCA methods applied to ultrasound with intra-arterial angiographic stenosis measurement.

PURPOSE: Carotid stenosis is usually determined on Doppler ultrasound from velocity readings. We wondered if angiography-style stenosis measurements applied to ultrasound images improved accuracy over velocity readings alone, and if so, which measure correlated best with angiography. MATERIALS AND METHODS: We studied prospectively patients undergoing colour Doppler ultrasound (CDU) for TIA or minor stroke. Those with 50%+ symptomatic internal carotid artery (ICA) stenosis had intra-arterial angiography (IAA). We measured peak systolic ICA velocity, and from the ultrasound image, the minimal residual lumen, the original lumen (ECST), ICA diameter distal (NASCET) and CCA diameter proximal (CCA method) to the stenosis. The IAAs were measured by ECST, NASCET and CCA methods also, blind to CDU. RESULTS: Amongst 164 patients (328 arteries), on CDU the ECST, NASCET and CCA stenosis measures were similarly related to each other (ECST = 0.54 NASCET + 46) as on IAA (ECST = 0.6 NASCET + 40). Agreement between CDU- and IAA-measured stenosis was similar for ECST (r = 0.51), and CCA (r = 0.48) methods, and slightly worse for NASCET (r = 0.41). Adding IAA-style stenosis to the peak systolic ICA velocity did not improve agreement with IAA over peak systolic velocity alone. CONCLUSION: Angiography-style stenosis measures have similar inter-relationships when applied to CDU, but do not improve accuracy of ultrasound over peak systolic ICA velocity alone.

Angiography↗

PubMed2005

Validity and responsiveness of the patient evaluation measure as an outcome measure for carpal tunnel syndrome.

The aim of this study was to assess the validity of the Patient Evaluation Measure questionnaire (PEM) as an outcome measure in carpal tunnel syndrome. The PEM was compared to the DASH questionnaire and to objective measurements of hand function. We also compared its responsiveness to changes following carpal tunnel release with that of the DASH score. Twenty-four patients completed the PEM and DASH questionnaires before and 3 months after open carpal tunnel release. Grip strength, static two-point discrimination and the nine-hole peg test were measured. There was a significant correlation between individual items of the PEM and the objective measures. There was also strong correlation between PEM and DASH scores. The PEM showed a greater responsiveness to change (effect size 0.97) than the DASH score (effect size 0.49). The PEM correlates well with objective measures of hand function and the DASH score when used in carpal tunnel syndrome. It is more responsive to change than the DASH score. It is very simple to complete and score and is an appropriate and practical outcome measure in carpal tunnel syndrome.

Adult↗

PubMed2026

Sensor-based measures of knee brace adherence have low agreement with self-report methods: A multi-measure study among knee osteoarthritis patients.

OBJECTIVE: To explore agreement between self-report and objectively measured adherence to brace wearing by patients with knee osteoarthritis. METHOD: A single-arm observational analysis nested within the PROP OA randomised controlled trial (ISRCTN28555470). Of 237 adults with symptomatic knee osteoarthritis randomised to brace treatment, 60 were included in this sub-study investigating three different methods of assessing knee brace wear time over 26 weeks: 1. Self-report questionnaires (SRQ) at 12 weeks and 26 weeks; 2. Short message service (SMS) questions (days worn in past week, typical hours per day when worn) administered from week 1 to week 24; 3. A skin temperature sensor embedded in the brace, sampling every 10 min for 26 weeks. The presence and reason for the sensor were concealed from participants. The estimated proportion of participants meeting "minimum brace use", defined a priori as ≥1 h on ≥2 days in past week, was described for each measurement method, overall and by brace type (unloader, neutral). For temperature sensor measurements, time spent above 24°C and time spent above 25°C were used. Agreement between the measures was summarised by percentage agreement and kappa (ĸ). RESULTS: The estimated proportions of participants meeting "minimum brace use" at 12 weeks were 83% (SRQ), 83% (SMS), 60% and 58% (temperature sensor, 24°C and 25°C thresholds, respectively). At 26 weeks, the corresponding estimates reduced to 72%, 71% (SMS at 24 weeks), 43% and 37%. Sensor data suggested the sharpest decline in brace use occurred within the first 12 weeks. Agreement between self-report measures was higher than between self-report measures and sensor (SRQ vs SMS at 12 weeks: 92% agreement, ĸ=0.67 (95%CI: 0.34, 1.00); SRQ vs Sensor at 12 weeks: 74%, 0.35 (0.10, 0.60); SMS vs Sens at 12 weeks: 76%, 0.36 (0.05, 0.66). Agreement between all measurement methods reduced at 26 weeks. CONCLUSIONS: This novel use of a temperature sensor to monitor brace adherence in knee osteoarthritis indicates that self-report adherence substantially overestimates knee brace wearing time, with implications for clinical trials and practice.

Humans↗

PubMed1998

Performance-based and self-assessed measures of visual function as related to history of falls, hip fractures, and measured gait time. The Beaver Dam Eye Study.

OBJECTIVE: The purpose of the study is to report relationships between visual function parameters and falls, hip fractures, and gait time in adults. DESIGN: Population-based study. PARTICIPANTS: The 3722 persons who participated in the 5-year follow-up of the Beaver Dam Eye Study cohort. MAIN OUTCOME MEASURES: The visual functions measured at the examination were best-corrected visual acuity, current binocular acuity, near acuity, contrast sensitivity, and visual threshold to light. Information on falls and hip fractures was obtained by structured interview. Gait time was measured by standardized protocol. RESULTS: History of falls and hip fractures increased with age, as did time to walk a measured course. Falls were more commonly reported for all persons who had poorer visual function, although not all relationships were significant in persons less than 60 years of age. In persons 60 years of age and older, hip fractures after the age of 40 were significantly related to all measures of visual function. Time to walk a measured course was significantly related to all measures of visual function. CONCLUSIONS: These data indicate a consistent relationship between falls, fractures, gait time, and visual functions. Longitudinal data are necessary to accurately determine temporal relationships and to determine the likelihood of a causal association. In the interim, these data suggest that improving visual function may have benefits such as decreased traumatic events and improved mobility.

Accidental Falls↗

PubMed2001

Automated edge-detection technique for measurement of brachial artery reactivity: a comparison of concordance with manual measurements.

Concerns have been raised about the reproducibility of brachial artery reactivity (BAR), because subjective decisions regarding the location of interfaces may influence the measurement of very small changes in lumen diameter. We studied 120 consecutive patients with BAR to address if an automated technique could be applied, and if experience influenced reproducibility between two observers, one experienced and one inexperienced. Digital cineloops were measured automatically, using software that measures the leading edge of the endothelium and tracks this in sequential frames and also manually, where a set of three point-to-point measurements were averaged. There was a high correlation between automated and manual techniques for both observers, although less variability was present with expert readers. The limits of agreement overall for interobserver concordance were 0.13 +/- 0.65 mm for the manual and 0.03 +/- 0.74 mm for the automated measurement. For intraobserver concordance, the limits of agreement were - 0.07 +/- 0.38 mm for observer 1 and - 0.16 +/- 0.55 mm for observer 2. We concluded that BAR measurements were highly concordant between observers, although more concordant using the automated method, and that experience does affect concordance. Care must be taken to ensure that the same segments are measured between observers and serially.

Automation↗

PubMed2002

Comparison of the responsiveness of the Barthel Index and the motor component of the Functional Independence Measure in stroke: the impact of using different methods for measuring responsiveness.

Two disability measures frequently used to assess the effects of interventions on stroke recovery are the Barthel Index (BI) and the motor component of the Functional Independence Measure (FIM Instrument). This study compared multiple measures of responsiveness of these instruments to stroke recovery between 1 and 3 months. Data on a 1- to 3-month change in the Instruments were obtained for 372 subjects who improved or maintained function on the modified Rankin Scale (MRS), using a subset of 459 eligible patients with confirmed stroke as defined by WHO criteria recruited from 12 participating hospitals in the Greater Kansas City area. Subjects were excluded because of death, early withdrawal from the study, missing MRS, or outcome data (57) decline on MRS (26), or inability to improve on MRS (4). Techniques used to assess responsiveness were: area under the ROC curve, Guyatt's effect size, paired t-statistics, standardized response mean, Kazis effect size, and mixed model adjusted t-statistic. The FIM Instrument and BI show little difference in responsiveness to change. The different responsiveness measures are generally consistent with this conclusion, with no measure clearly superior to the others. Large differences in the responsiveness measures were obtained within an instrument depending on the populations used (changers only or both changers and those who maintained function). Results also suggest responsiveness assessments are likely to be affected by time frame and phase of rehabilitation over which the responsiveness of a measure is determined.

Activities of Daily Living↗

PubMed2004

Atomic force microscopy colloid-probe measurements with explicit measurement of particle-solid separation.

We describe the use of evanescent wave scattering to measure the separation between the surface of a solid and a particle that is attached to an atomic force microscope (AFM) cantilever. Termed evanescent wave atomic force microscopy, our approach involves measuring the intensity of the light scattered from an evanescent field formed by the total internal reflection of a laser beam at a solid/fluid interface. In a conventional AFM "colloid probe" measurement, this separation must be inferred from an examination of the surface forces. Direct measurement of this separation with an evanescent wave atomic force microscope (EW-AFM) removes some ambiguity in the surface force measurement and, in addition, allows new types of measurements. For example, the force can be monitored at a constant separation. Our evanescent scattering apparatus is essentially identical to that used in total internal reflection microscopy (TIRM), except that we collect the light that scatters back into the incident medium, because the AFM partly obscures the forward scattered light (i.e., light scattered into the transmitted region). Compared to a conventional TIRM measurement, where the particle moves freely, attaching the particle to the cantilever in an EW-AFM gives much greater control of the particle position.

Journal Article↗

PubMed1997

Resonance frequency measurements of implant stability in vivo. A cross-sectional and longitudinal study of resonance frequency measurements on implants in the edentulous and partially dentate maxilla.

The aim of this investigation was to evaluate the use of resonance frequency measurements in the clinical measurement of implant stability. Resonance frequency measurements are undertaken by measuring the response of a small transducer attached to an implant fixture or abutment. Two groups of patients were selected for study. Group A comprised 9 patients who had a total of 56 implants placed. Resonance frequency measurements were made at fixture installation and repeated 8 months later at abutment connection. The resonance frequency of the implant/transducer system increased for 50 out of the 56 implants from a mean value of 7473 Hz +/- 127 Hz (P < 0.05) to a mean of 7915 Hz +/- 112 Hz (P < 0.05). Two implants had failed to integrate and the resonance frequency of these had fallen. Group B comprised 9 patients who had been provided with fixed prostheses and had a total of 52 implants placed. They were examined 5 years after fixture placement and the prostheses removed. All implants were judged clinically to be osseointegrated. The level of the marginal bone around each implant was calculated by measuring the number of exposed threads on intraoral periapical radiographs and added to the length of each abutment to give a value termed the effective implant length (EIL). Measurements indicated a correlation (R = -0.78, P < 0.01) between EIL and resonance frequency. The results support the hypothesis that the resonance frequency of an implant/transducer system is related to the height of the implant not surrounded by bone and the stability of the implant/tissue interface as determined by the absence of clinical mobility.

Aged↗

PubMed1990

A non-invasive method of measuring concentrations of rubidium in rat skeletal muscle in vivo by 87Rb nuclear magnetic resonance spectroscopy: implications for the measurement of cation transport activity in vivo.

1. We have used n.m.r. spectroscopy to measure rubidium concentrations in the skeletal muscle of live intact rats. Using a 1.9 T superconducting magnet and an ear-phone coil tuned to both protons (1H) and rubidium (87Rb), it was possible to make measurements of both tissue rubidium content and water content, and from these measurements to obtain the rubidium concentration. 2. The n.m.r. estimate of rubidium concentration in muscle in vivo was found to be a constant 31% (SEM 4%) of that estimated by flame atomic absorption spectroscopy in an extract of excised muscle. This is close to the predicted theoretical n.m.r. visibility of 33%. The visibility was constant for muscle rubidium concentrations ranging between 10 and 34 mmol/l. 3. Rubidium concentration measurement by this method is unaffected by variations in sample geometry, sample volume, tissue conductivity, coil tuning and amplifier gain. 4. By using this method to measure changes in tissue rubidium concentration with time in the same animal, it should now be possible to assess the activity of ion transport systems, such as sodium- and potassium-activated adenosine triphosphatase in vivo, by measuring the rates of change of tissue rubidium concentrations during the administration of rubidium salts. 5. This method could also be used to measure the absolute concentration of any n.m.r.-visible nucleus and could be applied to man.

Animals↗

PubMed2001

Forearm blood flow measurements using computerized R-wave triggered strain-gauge venous occlusion plethysmography: unilateral vs. bilateral measurements.

The human forearm is a well established model to study local vascular reactivity in humans in vivo, using strain-gauge venous occlusion plethysmography to measure blood flow and changes in blood flow in the forearm. To reduce the intra-individual variability of the forearm blood flow (FBF), it has been advocated that simultaneous measurements of contralateral forearm blood flow is obligatory. Therefore, the use of the calculated forearm ratio (FR) is recommended instead of using the actual FBF. In the present study we compared the intra-individual variability of forearm blood flow measurements and the forearm ratio, by using computerized R-wave triggered strain-gauge venous occlusion plethysmography, to test if bilateral expression of measurements is better than unilateral. Results were obtained in eight volunteers. Intra-arterial infused sodium nitroprusside induced a dose dependent increase in forearm blood flow and a dose dependent increase in the calculated forearm ratio. Intra-arterial infused norepinephrine induced a dose dependent decrease in forearm blood flow and a dose dependent decrease in the calculated forearm ratio. The differences between the variation coefficients of the forearm blood flow measurements and the calculated forearm ratio were different. These results support our hypothesis that by using a computerized, R-wave triggered system for unilateral forearm blood flow measurement is a more reliable outcome than the calculated forearm ratio derived from bilateral measurements.

Adult↗

PubMed2004

Measuring cardiac output in one-lung ventilation: a comparison of pulmonary artery and transpulmonary aortic measurements in pigs.

OBJECTIVE: The agreement between cardiac output measurements via pulmonary artery thermodilution (CO[PA]) and transpulmonary aortic thermodilution (CO[AT]) during one-lung ventilation was studied. DESIGN: Animal study with repeated simultaneous measurements comparing 2 cardiac output measurement techniques. SETTING: Experimental animal facility of a university department. PARTICIPANTS: Forty-eight female pigs (26-42 kg). INTERVENTIONS: The pigs were anesthetized, tracheally intubated, and mechanically ventilated. After placement of an aortic thermistor catheter via the femoral artery and a pulmonary artery catheter, a double-lumen tube was placed via tracheotomy. During one-lung ventilation in each animal, 3 measurements with pulmonary artery thermodilution and transpulmonary aortic thermodilution were performed in different hemodynamic states. Both thermistors were connected to 1 computer system, and 144 simultaneous cardiac output measurements were analyzed. MEASUREMENTS AND MAIN RESULTS: Linear regression analyses revealed a close relationship between the 2 methods: CO(AT) = 0.81 CO(PA) + 1.04 (L/min) (r = 0.96, p < 0.0001). Bland-Altman analysis showed that CO(AT) was slightly higher than the CO(PA) with a bias of 0.2 +/- 0.5 L/min. However, in higher CO states, an inversion of this relationship was found, possibly because of indicator loss and recirculation. CONCLUSIONS: The pulmonary artery thermodilution and the transpulmonary aortic thermodilution techniques both accurately measure cardiac output during one-lung ventilation.

Animals↗

PubMed2000

The measurement properties of fitness measures and health status for persons with spinal cord injuries.

OBJECTIVE: To assess the measurement properties of measures used to evaluate fitness and health status in the spinal cord injury (SCI) population. DESIGN: Inception cohort assessed during standardized exercise protocols at admission, discharge, and 8-week follow-up from a SCI rehabilitation program. SETTING: Urban tertiary care hospital. PATIENTS: One hundred two patients with SCI. RESULTS: Measures at higher levels of physical exertion generally showed higher stability between test and retest. Resting measures, blood lactates, and respiratory exchange ratios were not stable. Heart rate, blood pressure, lactate levels, ventilation rates, and activities of daily living measures did not reflect the construct of aerobic fitness. The use of ratings of perceived exertion to predict heart rate was found to be inaccurate in the SCI population. CONCLUSION: Power output and VO2 at maximal workload, and ratings of perceived exertion at a standard workload demonstrated stability and sensitivity to therapeutic change, indicating acceptable measurement properties for the assessment of aerobic fitness in SCI patients. Some other commonly used measures can be used with less confidence.

Adult↗