Standard Ramp Research Articles

Physiologic Status of Oncology Patients Awaiting Abdominal Surgery

PURPOSE: Increasingly exercise training is being used as a non-pharmacologic therapeutic intervention to reduce the effects of both the disease and the treatment. While these patients benefit from exercise training, little is known about their physiologic status. Such information is needed to maximize the effectiveness of exercise training. Therefore, this study sought to determine the safety and feasibility of using cardiopulmonary exercise testing (CPET) application in an oncology patient population. METHODS: After receiving physician clearance, 130 subjects (100 males, 30 females) with abdominal, gastrointestinal and urinary tract tumors underwent a standard ramp bicycle ergometer CPET within two weeks of scheduled surgery. The exercise protocol sequentially entailed 3 min of quiet resting, 3 min of unloaded cycling, ramp protocol to peak exercise tolerance, and 3 min of recovery. Ramp rates (5-25 W/min) were individually chosen to achieve standard test durations of 8-12 min per patient. CPET parameters were analyzed by Harbor-UCLA standard methods. Tests were symptom limited. This protocol was approved by the UT MD Anderson Cancer Center Institutional Review Board. RESULTS: Subjects age (mean + SD) was 58.9 + 12.7 yrs. and their BMI was 29.0 + 6.25. Peak VO2 averaged 19.8 + 6.1 ml·kg−1·min−1 or 78.7% of predicted peak VO2. Heart rate (141 + 24 BPM) at peak work load (120 + 51 W) averaged 87% of age predicted peak heart rate. Mean respiratory exchange rate at peak VO2 was 1.2 + 0.1. No adverse events occurred during testing. CONCLUSIONS: This oncology patient population appears able to tolerate and safely complete a symptom limited CPET. Results suggest that this patient population is less fit than age-matched healthy individuals which may put them at greater risk for adverse surgical outcomes.

The Ramp Power Test: A Power Assessment During a Functional Task for Older Individuals

Power is critical to mobility and activities of daily living and is a key determinant of independence and falls prevention. Therefore, the quantification of power in older persons is critical. The power tests currently available are often expensive, potentially dangerous, and not reflective of everyday activities. We present a modification of an existing field test that uses ambulation up a standard access ramp to quantify functional power in older individuals. Three hundred sixty-three women and 157 men, aged 73.1 +/- 7.0 years, ambulated up a standard access ramp (1:12 rise/run ratio) as quickly as possible. Each person performed one practice and two timed trials. Comparisons with accepted power measures and reported patterns of change with aging supported the validity of the ramp power test. The test was found to be reliable across multiple trials and days. Pair-wise comparisons showed that for women the test was sensitive to differences in power output by half-decade, whereas for men it could distinguish between 9 of the 15 comparisons among age groups. Percentile scores are reported by half-decade for power in both genders. In > 1200 trials performed during this study, only one injury (a slightly strained hamstring) occurred. The ramp power test is valid and reliable and can safely distinguish power by half-decade in women and among the majority of age groups in men. Its safety, low cost, and ease of administration make it a feasible diagnostic tool to assess functional power levels in ambulatory older persons.

Training Induced Changes in Maximum Heart Rate

The present study aimed to examine maximum heart rate (HRmax) in elite athletes. 130 (68 male, 23.2 +/- 4.8 years, 62 female, 21.0 +/- 5.1 years) endurance trained athletes, 40 (24 male, 24.0 +/- 5.6 years, 16 female, 22.8 +/- 4.6 years) anaerobically trained athletes, and 95 (39 male, 24.8 +/- 4.8 years, 56 female, 23.0 +/- 4.8 years) sedentary participants entered the study. All participants undertook a standard ramp protocol to volitional exhaustion to establish HRmax. Significant differences in HRmax were identified due to mode of exercise (p < 0.001) and gender (p = 0.001). The mean HRmax for the three modes of exercise were; aerobic 190.3 (SEE = 0.66), anaerobic 190.1 (SEE = 1.12) and sedentary 194.8 (SEE = 0.73) beats . min (-1) estimated at the average age of 23.1 years. The slope parameter for age varied between genders, the beta slope for females being significantly more negative than male subjects (- 1.1 beats . min (-1) . year (-1) vs. - 0.55 beats . min (-1) . year (-1), respectively). The predictive HRmax equation for male athletes was HRmax = 202 - 0.55 x age, and for female athletes it was HRmax = 216 - 1.09 x age. HRmax is similar between aerobically and anaerobically trained athletes. HRmax is significantly lower in athletes compared with age matched sedentary counterparts. The mechanisms underlying the lower HRmax remain to be elucidated.

The cardiopulmonary exercise test is safe and reliable in elderly patients with chronic heart failure

To assess safety and feasibility of cardiopulmonary exercise test (CPX) in elderly patients with chronic heart failure (CHF) and left ventricular dysfunction. We analysed 395 cardiopulmonary exercise tests (CPXs) performed in 227 clinically stable patients with CHF [mean age 76 years, males 70%, mean New York Heart Association (NYHA) class 2.2 +/- 0.5] and impaired left ventricular function (mean ejection fraction 43 +/- 12%). Ninety-eight out of 395 CPXs (25%) were performed in patients older than 80 years. A standard bicycle exercise ramp protocol was used, with increments of 10 W/min. An expiratory exchange ratio (RER) >or= 1.05 at the peak of CPX was considered as the index of maximal exercise. Average workload was 65 +/- 23 W. No adverse reactions were observed, although one test was stopped for non-sustained ventricular tachycardia. The main reasons for stopping were exhaustion (50%), dyspnoea (30%), maximal predicted heart rate (17%), orthopaedic problems (2.5%) and significant ST segment depression (0.5%). In the overall cohort, 80% of patients achieved an RER >or= 1.05 and, in 56% of them, the RER was >or= 1.15. The anaerobic threshold (AT) was detectable in 80% of CPXs, and mean oxygen consumption (VO2) at AT was 9 +/- 6 ml/kg per min, whereas mean peak VO2 was 11 +/- 3 ml/kg per min. In the cohort of patients aged > 80 years, 71% reached an RER >or= 1.05 and 47% reached an RER >or= 1.15. In these older patients, AT was detectable in 68% of CPXs performed, and the mean peak VO2 was 10 +/- 3 ml/kg per min. In elderly patients with CHF, the CPX is safe, feasible and able to provide basic information for individual risk assessment. These findings potentially extend the indications of CPX, which is currently applied to selected middle-aged patients with CHF, to the elderly population.

Development and evaluation of an exact fan‐beam reconstruction algorithm using an equal weighting scheme via locally compensated filtered backprojection (LCFBP)

A novel exact fan-beam image reconstruction formula is presented and validated using both phantom data and clinical data. This algorithm takes the form of the standard ramp filtered backprojection (FBP) algorithm plus local compensation terms. This algorithm will be referred to as a locally compensated filtered backprojection (LCFBP). An equal weighting scheme is utilized in this algorithm in order to properly account for redundantly measured projection data. The algorithm has the desirable property of maintaining a mathematically exact result for: the full scan mode (2pi), the short scan mode (pi+ full fan angle), and the supershort scan mode [less than (pi+ full fan angle)]. Another desirable feature of this algorithm is that it is derivative-free. This feature is beneficial in preserving the spatial resolution of the reconstructed images. The third feature is that an equal weighting scheme has been utilized in the algorithm, thus the new algorithm has better noise properties than the standard filtered backprojection image reconstruction with a smooth weighting function. Both phantom data and clinical data were utilized to validate the algorithm and demonstrate the superior noise properties of the new algorithm.

車いす避難時の安全性の向上を目的とした多段型スロープの提案 その2 : 車いすによる昇降のしやすさを考慮した避難スロープの開発に関する研究

Experimental travel by wheelchair users were made to compare accessibility of normal ramps and two pieces of step-by-step ramps, and travelability on a long 1:20 gradient standard ramp. The results are as follows; 1) The travel estimation is affected by the difference of state of arms of wheelchair users. 2) Step-by-step ramps are more accessible and safer than normal ramps for wheelchair users. 3) Intermediate landings help decelerate downward travel speed. 4) It is difficult to travel up a long 1:20 gradient ramps, and dangerous to travel them down due to acceleration.

AN ADL-RELATED METHOD FOR ASSESSING POWER OUTPUT IN SENIORS

Power is essential in performing activities of daily living (ADL). Power decreases during the aging process, but few tests exist that assess power in relationship to function, i.e., tasks performed during ADLs. PURPOSE To establish a functionally appropriate method for determining power output in older persons. METHOD 347 female and 156 male subjects aged 73.1±7.0 years participated in the study. Power output was determined by a modified Margaria-Kalamen test requiring subjects to move as fast as possible up a standard access ramp (1:12 rise). Subjects performed 1 practice and 2 timed trials. RESULTS Pair-wise comparisons between half-decade age groups revealed significant differences in power output among groups at the adjusted alpha level of p =.0017. These differences were detected among all groups that differed in age by at least 5 years. Results allowed percentile scores to be developed by half-decade for both genders. CONCLUSION Our results suggest that this modification of the ramp Margaria-Kalamen power test is able to quantify and distinguish ADL-related power by half-decade in both genders of older individuals.

Estimating the parameters of aerobic function during exercise using an exponentially increasing work rate protocol.

A new exercise protocol has been proposed, with respect to cardiopulmonary exercise testing, which starts at a low work rate (WR) and increases exponentially by a standard percentage of the previous work rate every minute: the test is termed STEEP (standardised exponential exercise protocol). The potential advantage of this protocol is that it can accommodate a wide range of subjects, since it allows a maximum to be attained with a relatively narrow variation of tolerance time, regardless of subjects exercise capacity. To date, only the VO2max has been compared with that from the current standard ramp protocol. The ramp, however, also allows other important parameters of aerobic function to be estimated: the anaerobic threshold (AT); the response time constant; and delta VO2/delta WR. The aim of this study was, therefore, to clarify whether these aerobic parameters can be readily discerned from the responses to the STEEP protocol both from a theoretical and practical viewpoint. As a result of theoretical considerations, we demonstrated that the VO2 time constant and delta VO2/delta WR may not both be estimated uniquely. As a practical expedient, a procedure was proposed for estimating the parameter analogues. The preliminary results for six subjects between the STEEP and ramp protocols showed consistent positive correlation for VO2max (r = 0.997) and AT-VO2 (r = 0.980), whereas the correlation for the VO2 time constant and delta VO2/delta WR were not significant. Further study is needed to clarify the reason(s) for the discrepancies both from a theoretical and practical viewpoint.

A method for the determination of mechanical parameters in a porous elastically deformable medium : applications to biological soft tissues

A further approach has been tentatively envisaged for the determination of the mechanical parameters characterizing the unsteady behaviour of soft biological tissues considered as porous, elastically deformable media, saturated with a viscous fluid. If the two solid and fluid phases are incompressible, the parameters to be determined are : the drained Young’s modulus and Poisson’s ratio, the permeability of the porous solid structure and the dynamic viscosity of the interstitial fluid. Standard ramp–relaxation tests have been performed in order to investigate the time evolution of the force acting upon tissular discoïdal samples subjected to unconfined compressive strains, under controlled environmental conditions. For moderate compressive strains, such a response in resultant force, characterizing a stress diffusion phenomenon within the medium, can be analyzed using a spectral decomposition with orthogonal eigenvectors. Such an analysis reveals that the overall response is defined by its asymptotic behaviour during both compression and relaxation phases, leading to the evaluation of the Young’s modulus and Poisson’s ratio. Moreover, the determination of the relaxation time leads to the evaluation of the specific permeability of the structure—the dynamic viscosity of the fluid being already known. A few examples of experimental tests data, involving both rubber foam, myocardium tissue in passive state and fibroblastic biological collagenic gels, are presented here in order to illustrate and validate such a rheological methodology. Particular attention is paid to the relations between the poroelastic behaviour and microstructural parameters of the material, with an emphasis on possible nonlinear effects arising from these very deformable media.

THE EFFECT OF ALTERING RAMP RATE ON THE DETERMINATION OF LACTATE MINIMUM IN CYCLISTS

1738 Several studies have shown that the determination of the lactate minimum point (Lacmin, Tegtbur et al., 1993) is greatly influenced by the starting exercise intensity. No studies to date have investigated the effect of altering the ramp rate of the Lacmin test. Eight male racing cyclists (mean±SD: age, 27±2 yrs; height, 1.81±0.04 m; body mass, 72.9±1.6 kg; ˙VO2max, 5.32±0.13 l·min-1; maximum power output (MPO) 452.75±11.83 W) volunteered to participate. To create a lactate preload subjects completed a standard ramp maximal test, using their own bicycles on a windload simulator -`Kingcycle' - (to determine ˙VO2max and MPO) followed by a 5 min recovery period at ≈75 W. Starting at 60% MPO subjects then completed three tests in a random order on separate days: 3 and 6 W·min-1 ramp protocols to determine the Lacmin, and a control condition for which the starting intensity was maintained throughout. During these tests˙VO2 was measured continuously, heart rate every 5s, with mixed capillary finger tip blood samples taken every min for [lactate] determination. Results from the three tests revealed that blood [lactate] values declined curvilinearly at the same rate (by ≈54%, ΔLac 5.50±1.24mM) in the first 5 min of the Lacmin test. The 3 W·min-1 ramp resulted in significantly (p<0.05) lower power at the Lacmin point, compared with the 6 W·min-1 ramp(304.8±25.6 vs 313.0±27.2 W). These observations suggest that the decline in blood lactate concentration was time and not intensity dependent and that the ramp rate does affect the determination of the Lacmin point in cyclists.

Analyzing the Ultimate Capacity of a Precast Segmental Box Girder Bridge

The second State Expressway System (SES) in Bangkok, Thailand includes about 32km of elevated roadway. The precast concrete segmental part of this roadway consists of about 1130 box girder spans of lengths 24.9m to 48.8m. Because of the large investment involved, it was cost-effective to produce a prototype test span, to confirm the adequacy of the design. This paper compares the full-scale destructive test of the span with an analytical analysis of its performance. The test span was designed according to the 1983 AASHTO Standard Specifications and the 1989 AASHTO Guide Specifications for Segmental Bridges. A live load was used, with an overload provision of 27.8t trucks at 11.15m spacing occupying one lane. The span corresponded to the SES standard two-lane ramp; it was 45.25m long, with a 14-segment 10.2m wide deck. Its longitudinal tendons were external, and deviated at three locations within the span. Steel billets were used to induce test loading. Before the test span's ultimate loading, a computer program was run to estimate the span's ultimate behaviour. The paper describes the girder behaviour and the flexural strength analysis. The unbonded computer model adequately predicted the test span's ultimate capacity, and made various other predictions about the span's failure.

Small scale isothermal age technique to determine exothermic onset temperatures

With the increased focus on safety in the chemical industry, there is a greater demand for reliable information as to exothermic onset temperatures before the scale-up of any process. The Small Scale Isothermal Age (SSIA) test is an isothermal DSC technique in which reusable metal crucibles are used to accurately determine exothermic onset temperatures. A typical solid sample, 50–75 mg, is held isothermally at a preset temperature for an extended period of time, usually 12–16h. The aged sample is then run at a standard heat-up ramp to determine any decrease in the size of the original exotherm relative to the unaged sample. The same DSC cell, metal crucible, heat-up rate and sample weight are used to determine the exotherm size in both the unaged and aged sample. The SSIA technique is applicable to both solids and liquids and has the advantages of: i) small sample size, (ii) handling of compounds in which exothermic activity is accompanied by large pressure increases without damaging experimental equipment, (iii) accurate determination of exothermic onset temperature, (iv) ease of experimental set-up, (v) ease of data interpretation, and (vi) rapid experimental turn-around time. The determination of the exothermic onset temperature using the small scale isothermal age technique will be presented and results compared to data obtained using standard and small dewar techniques.

A wavelet-based method for multiscale tomographic reconstruction

The authors represent the standard ramp filter operator of the filtered-back-projection (FBP) reconstruction in different bases composed of Haar and Daubechies compactly supported wavelets. The resulting multiscale representation of the ramp-filter matrix operator is approximately diagonal. The accuracy of this diagonal approximation becomes better as wavelets with larger numbers of vanishing moments are used. This wavelet-based representation enables the authors to formulate a multiscale tomographic reconstruction technique in which the object is reconstructed at multiple scales or resolutions. A complete reconstruction is obtained by combining the reconstructions at different scales. The authors' multiscale reconstruction technique has the same computational complexity as the FBP reconstruction method. It differs from other multiscale reconstruction techniques in that (1) the object is defined through a one-dimensional multiscale transformation of the projection domain, and (2) the authors explicitly account for noise in the projection data by calculating maximum a posteriori probability (MAP) multiscale reconstruction estimates based on a chosen fractal prior on the multiscale object coefficients. The computational complexity of this maximum a posteriori probability (MAP) solution is also the same as that of the FBP reconstruction. This result is in contrast to commonly used methods of statistical regularization, which result in computationally intensive optimization algorithms.

978-65 Exercise Forearm Vascular Responses in Patients Studied 7 Days After Myocardial Infarction

We have reported that exercise hypotension in patients with ischaemic heart disease may be due to abnormal vasodilation, Whilst exercise hypotension is not common in post infarction patients, we hypothesised that forearm vascular responses may commonly be abnormal. We assessed the frequency of abnormal forearm vascular responses in an unselected group of patients studied 7 days post myocardial infarction and the association with exercise blood pressure (BP) responses and with baroreceptor gain. Forty consecutive consenting patients (36 male 4 female age 33–74 mean 56.2 years) were studied 7 days post myocardial infarction and were compared with 20 healthy controls (14 male 6 female age 44–69 mean 56.2 years). All subjects underwent assessment of changes in forearm vascular resistance (FVR) by venous occlusion plethysmography during semi erect exercise, BP recordings during erect treadmill exercise, and baroreceptor gain assessed by the change in RR interval per unit change in blood pressure induced by phenylephrine (standard phenylephrine ramp method). (expressed as mean ± SD): FVR increased during exercise by 41 ± 67% in patients versus 124 ± 110% in controls (p = 0,001), and fell in 12 patients. Using an increase of 15% (one standard deviation below the mean for the controls) as the cut off for normality, 15 patients exhibited abnormal exercise vascular responses. Exercise hypotension was demonstrated in 4 patients all of whom had abnormal forearm vascular responses. Baroreceptor gain was lower in patients with abnormal forearm vascular responses than those with normal forearm vascular responses (24 ± 62, msec/mmHg vs 73 ± 67 msec/mmHg, p = 0.04). Impaired forearm vasoconstriction or vasodilation during leg exercise is common in patients studied 7 days post MI, even in patients without exercise hypotension and is associated with low baroreceptor gain. Exercise hypotension may only result in patients with abnormal forearm vascular responses, if they are unable to augment cardiac output. The absence of exercise hypotension in the majority of these patients implies a vigorous cardiac output response

The clearance rate of exercise-elevated blood lactate following physical training.

In this paper, previous studies regarding the effect of physical training on the disappearance rate of blood La during recovery after strenuous exercise have been briefly summarized. The results of our own recent study of this problem have also been added. It may be concluded that there is some evidence for an improved lactate metabolic clearance rate resulting from physical training in human subjects, when the degradation rate is estimated from serial blood samples taken during a standard ramp ergometer test to exhaustion during each week of a training/detraining sequence. This beneficial effect of training, however, may also be influenced by the initial physical status of the subject and the nature of the training program.

Effects of changes in preoptic temperature on stretch response of muscle spindle endings in the cat's soleus muscle.

The effects of changing the temperature in the preoptic region on the stretch responses of primary and secondary endings of the muscle spindle in the soleus muscle was investigated in urethane anesthetized cats. The local temperature of the preoptic region was controlled by implanting water perfused thermodes (32-42.5 degrees C). A standard ramp and hold stretch stimulus was repeatedly applied to the soleus muscle during changes of preoptic temperature from normal to hypo- or hyperthermic values. During each stretch the instantaneous firing rate was recorded and the static firing frequency and the dynamic index were electronically determined according to Crowe and Matthews (1964). Of a total of 76 investigated muscle spindle afferents, the stretch responses of 49 (65%) were altered by changing preoptic temperature. The static stretch response was increased in all cases during cooling, whereas during preoptic heating the static stretch response increased in about half of the afferents and decreased in the rest. Increase in the static stretch response during both cooling and heating was usually combined with the appearance of spontaneous discharges at rest. With regard to the static stretch response, primary and secondary muscle spindle endings responded similarly to cooling and heating. Two types of preoptic temperature effects on the stretch responses of primary endings were observed. In the majority of afferents only the static stretch response was augmented during cooling, whereas the peak response was little changed resulting in a decrease of the dynamic index ('static' response type).(ABSTRACT TRUNCATED AT 250 WORDS)