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Biomedical subjects

R A Sherman

Publications and source records attributed to R A Sherman.

At least 55 records · Page 3Linked to original sources
PubMed1994

Reliability of an ambulatory electromyographic activity device for musculoskeletal pain disorders.

A number of investigators in recent years have called for the development of devices that can monitor surface EMG levels in individuals' normal environments for use with patients who suffer from disorders in which the etiology or maintenance of the pathology is presumed to be due at least in part to musculoskeletal dysfunction, such as low back pain, phantom limb pain and tension headache. This study examined the test-retest reliability of just such a device. Twenty-six healthy controls wore a lightweight (24 ounce) device which measured bilateral upper trapezius EMG, as well as peak and integral motion, for 5 consecutive days for up to 18 h each day. ANOVAs on the four measures revealed no difference between any of the four measures over the 5 days. Intra-class correlation coefficients for the two EMG variables across 5 days were both significant with alpha levels set at 0.01. The two EMG measures were highly correlated (r = 0.77); the two motion measures were also highly correlated (r = 0.60), but at a lower magnitude than EMG values; the relationship between EMG and motion was significant, but the magnitude of the between EMG motion correlations (0.26 and 0.35) were lower than the within EMG or motion ones. It was concluded that the test-retest reliability of the ambulatory monitoring device is within acceptable limits. Implications for the use of the device with musculoskeletal pain disorders--particularly headache--are discussed.

Adult↗
PubMed1994

Recirculation reassessed: the impact of blood flow rate and the low-flow method reevaluated.

The recognition that during hemodialysis the blood urea nitrogen level in a peripheral vein differs substantially from that in an artery has made invalid the conclusions of prior studies based on the standard (peripheral vein) means of calculating recirculation. The increase in recirculation associated with an increase in blood flow may be artifactual, as may the reported inaccuracy of the two-needle low blood flow technique for measuring recirculation. Using a stop-flow technique to measure recirculation, a study was performed to reassess these issues. Sixteen patients were each studied once within the first 30 minutes of a standard hemodialysis session (mean, 3.78 hour) at routine blood flow (mean, 419 mL/min) and at 200 mL/min. Dialyzer afferent and efferent blood line samples were obtained, as were afferent samples after sequential, rapid reductions in blood flow to 200, 50, and 0 mL/min. The final two samples were obtained within 30 seconds of reducing blood flow to less than 200 mL/min. Blood flow had a significant (P = 0.03) although clinically minor effect on recirculation (mean, 13.9% at 419 mL/min v 10.2% at 200 mL/min). The low blood flow technique yielded the same results as the stop flow technique (stop flow technique 13.9% v low blood flow technique 13.2% at 419 mL/min, P = 0.76). We conclude (1) that the increase in recirculation associated with increased blood flow is substantially less than has been reported previously and is minimal in a well-functioning access, and (2) that a modified low blood flow (50 mL/min) technique for measuring recirculation yields results equivalent to those obtained using the stop flow technique.

Adult↗
PubMed1994

Deficiencies in delivered hemodialysis therapy due to missed and shortened treatments.

The frequency of missed and shortened hemodialysis treatments was assessed in a randomly selected sample of 860 ESRD patients from 54 dialysis units. Data were collected for three sequential 4-week periods covering 28,108 treatments. During each of these 4-week periods, 5.1% to 7.6% of patients missed at least one treatment, 26.8% to 32.3% of patients had at least one shortened treatment, and 6.6% to 7.9% of patients missed 10% or more of their prescribed therapy. Over the entire 12-week period, 50% of patients had either missed or shortened treatments (or both). Missed and shortened treatments are prevalent enough to account for clinically important deficiencies in delivered dialysis for a significant number of patients.

Female↗
PubMed1994

The effect of dialyzer reuse on dialysis delivery.

It is well documented that the reprocessing of dialyzers may reduce their solute clearance capabilities. However, the effect of dialyzer reuse has never been assessed in an uncontrolled clinical practice setting. We addressed this issue in a prospective 436-patient, 34-center study. All patients underwent formal urea kinetic modeling monthly, usually for 3 sequential months. Dialyzers were reprocessed and reused in the usual manner for each unit. As a result, urea kinetic modeling was performed in individual patients using dialyzers with differing numbers of prior uses. For each patient, Kt/V urea for the treatment using the dialyzer with the most reuses (mean, 13.8) was compared with that with the treatment using the dialyzer with the fewest reuses (mean, 3.8). The mean Kt/V delivered for high reuse treatments was significantly lower than that for low reuse treatments (1.05 v 1.10, P = 0.002). Prescribed Kt/V in high and low reuse treatments was identical. Individual centers appeared to differ substantially (P = 0.06) in the effect of reuse on delivered Kt/V. Of the 23 centers using formalin-based reprocessing, an average difference of > or = 0.12 (mean, 0.17) in Kt/V between high and low reuse treatments was seen in 10 centers. Dialyzer reprocessing significantly impairs dialysis delivery, an effect that may be related to the methods and procedures in individual dialysis centers.

Acetic Acid↗
PubMed1994

Stability of temperature asymmetries in reflex sympathetic dystrophy over time and changes in pain.

OBJECTIVE: To determine the clinical usefulness of skin temperature patterns for tracking reflex sympathetic dystrophy (RSD) by assessing (a) long-term relationships between changes in pain due to RSD and patterns of near surface blood flow and (b) relationships between site of pain and site of greatest asymmetries in near surface blood flow patterns. DESIGN: Multiple videothermographic evaluations of near surface blood flow patterns were performed on subjects diagnosed as having RSD. At each session, subjects filled in an outline of the body to show the location, intensity, and description of their pain. The thermograms were evaluated independently by two raters for location and intensity of pain, as well as location and degree of temperature asymmetries. SETTING: Two Army Medical Centers. SUBJECTS: Thirteen male and 16 female subjects were subsequently diagnosed as having RSD. OUTCOME MEASURES: Ratings of pain and videothermograms of the lower limbs were used as outcome measures. RESULTS: All but one subject were usually cooler on the most painful side by at least 0.5 degrees C. The amount of relative coolness was not proportional to pain intensity. There were no consistent overlaps between exact location of pain and greatest thermal asymmetry. Seven subjects were thermally symmetrical on at least one recording. Six subjects were warmer on the affected side on at least one recording. One subject was always warmer on the affected side. CONCLUSIONS: Videothermography is not an appropriate tool to use alone for either single session diagnosis or multi-session tracking of RSD.

Adolescent↗
PubMed1994

The peritoneal permeability and surface area index.

The value of the peritoneal equilibration test (PET)-derived dialysate-to-plasma creatinine ratio (D/Pcr) as a measure of the peritoneal membrane's diffusive characteristics is obscured by the major role of convection in determining this value, particularly for low transporters. A simple index, derived from PET data, may permit a more accurate clinical measure of peritoneal diffusion.

Creatinine↗
PubMed1994

Phantom limb pain. Mechanism-based management.

Clinically significant phantom limb pain occurs among a large minority of amputees. Most suffer at least occasional episodes. It is becoming increasingly apparent that although psychological factors are not important in the cause of phantom pain, a variety of physiologic problems related to the residual limb are critical to it. Referred pain, initiated by decreased blood flow and microspasms in the residual limb along with problems caused by prosthetics account for most of the phantom pain problems seen clinically. Some pain is referred to the phantom pain from other sites in the body such as the back. Treatments for phantom pain that are not based on recently elucidated physiologic mechanisms have proven to be ineffective for the vast majority and cannot be applied indiscriminantly with any hope of consistent success. Mechanism-based treatments related to specific symptoms can be effective when used appropriately. They include the use of peripheral vasodilators, muscle relaxants, and biofeedback to correct specific problems with blood flow and muscle tension in the residual limb.

Anxiety↗
PubMed1993

Racial differences in the delivery of hemodialysis.

Differences in the quality of medical care provided to black and white patients have been observed in the United States, but have not been studied in dialysis patients. We examined whether dialysis delivery, as measured by indirect determination of Kt/V, differs between black and white patients in New Jersey. Five hundred forty-four patients at 10 New Jersey dialysis units were randomly selected by the US Health Care Financing Administration as part of their Medical Case Review Study. Of these, 237 patients at eight units were classified as black or white and had urea kinetic data available. The mean Kt/V urea was higher for white than black patients at all facilities, averaging 1.03 for the 123 black patients and 1.20 for the 114 white patients (P = 0.0006). Black patients were 40% more likely than white patients to have a Kt/V less than 1.0 (45.6% of black patients v 32.5% of white patients, P = 0.038). Racial disparities in dialysis delivery exist, the causes and consequences of which need to be addressed.

Black or African American↗
PubMed1993

The measurement of dialysis access recirculation.

The measurement of dialysis access recirculation has important diagnostic implications. Recent recognition that its traditional means of measurement is fraught with the potential for substantially overestimating access recirculation requires that we alter current practice. Most of the potential error in the measurement can be overcome by using an arterial rather than a venous specimen for the "systemic" sample. For practical purposes, such a sample can be drawn from the dialysis afferent (arterial) line as long as it is done in a manner that minimizes both contamination by recirculated blood as well as the increase in blood urea nitrogen that occurs when the arteriovenous blood urea nitrogen gradient is dissipated by slowing or stopping dialysis.

Arteriovenous Shunt, Surgical↗
PubMed1993

The effect of interdialytic weight gain on predialysis blood pressure.

Interdialytic weight gain is believed to influence predialysis blood pressure. Since interdialytic weight gains vary among treatments for individual patients, blood pressure and weight gain data could be examined to determine how weight variations correlate with differences in blood pressure. Therefore, the quantitative effect on prehemodialysis blood pressure of typical interdialytic weight gains was prospectively studied in 19 nondiabetic patients on chronic hemodialysis. Over a mean of 23.6 treatments (range 17-25), the slope of each patient's prehemodialysis blood pressure versus excess weight (prehemodialysis weight minus baseline dry weight) was determined. The mean slope of the prehemodialysis mean blood pressure/excess weight regression line was 1.2 mm Hg/lb excess weight. No significant correlation was found between individual prehemodialysis blood pressure/excess weight slopes and patient age (r = 0.20), months on dialysis (r = 0.33), dry weight (r = 0.05), or mean excess weight (r = 0.19). Slopes did not differ for 3-day versus 2-day interdialytic intervals, hypertension-treated versus untreated patients, or men versus women. In 5 patients, individual prehemodialysis mean blood pressure/excess weight slopes were significantly greater than 0, averaging 2.4 mm Hg/lb excess weight (vs. 0.8 mm Hg/lb in the remaining patients). These 5 volume-responsive patients did not differ clinically from the 14 volume-resistant patients. The weight gains commonly observed in patients undergoing chronic hemodialysis have only a modest effect on prehemodialysis blood pressure in the majority of patients.

Adult↗
PubMed1992

Temporal relationships between changes in phantom limb pain intensity and changes in surface electromyogram of the residual limb.

Previous studies of relationships between surface EMG of the residual limb and phantom pain have not shown which changed first. Thus, predictive relationships could not be demonstrated. 24 male (20) and female (4) amputees between the ages of 33 and 71 who reported either burning (3), cramping (8), shocking-shooting-stabbing (6), or a combination of these descriptions of phantom pain (7) participated in one or two recording sessions. Raw surface EMG from the major muscles of the residual limb was recorded while subjects activated an event marker to indicate changes in pain. All eight subjects with cramping phantom pain reported changes in pain after the recording showed sharply demarcated increases in EMG. Subjects reporting either shocking-shooting or burning pain did not show any consistent relationships between EMG and pain. Three of the four subjects reporting experiencing both shocking-shooting and cramping phantom pain simultaneously during recordings showed changes in EMG preceding changes in pain. Sensations of cramping phantom pain were preceded by increases in muscle tension in the residual limb in almost every instance for each of our subjects showing changes in cramping phantom pain. Thus, changes in muscle tension in the residual limb are likely to either be causes or close intermediaries for the cause of cramping phantom pain but not necessarily of other common descriptors.

Adult↗
PubMed1992

Light chain nephropathy in a 19-month-old boy with AIDS.

A 19-month-old boy with AIDS developed clinically unexplainable proteinuria. Biopsied renal tissue was examined by light microscopy, transmission electron microscopy, and immunofluorescence. Findings included an increase of mesangial matrix with occasional nodular sclerosis, mesangial hypercellularity, and glomerular deposits of kappa and lambda light chains. There were deposits of kappa, but not lambda, light chains in the arteriolar walls, and around the tubular and interstitial capillary basement membranes. Quantitative urinary immunoelectrophoresis revealed an extremely high urinary concentration of kappa light chain. These changes are diagnostic of light chain nephropathy. The rarity of light chain nephropathy in childhood and its occurrence in a patient with AIDS make this case unusual.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Value of clinical screening for detection of asymptomatic hemodialysis vascular access stenoses.

Measurement of recirculation and intradialytic venous line pressures may aid in the detection of hemodialysis vascular access stenoses. The authors screened 29 consecutive asymptomatic patients for recirculation values exceeding 15% or venous pressures greater than 150 mmHg. All 13 patients requiring and agreeing to angiography on the basis of the screening protocol proved to have high-grade stenoses of their vascular access outflow or inflow. Asymptomatic vascular access pathology is common. High-risk asymptomatic populations may be detected by simple screening procedures.

Angiography↗
PubMed1991

Assessment of a two-needle technique for the measurement of recirculation during hemodialysis.

The definitive measurement of recirculation in a hemodialysis vascular access for hemodialysis requires a peripheral vein blood sample. A two-needle method that avoids this venipuncture by using an "arterial" line sample from the access under low-flow conditions has been recommended. However, this technique has never been assessed in patients with significant levels of recirculation. We compared this low-flow arterial (LFA) technique to the standard method of measuring recirculation in 15 consecutive patients with more than 15% recirculation (mean, 27.6%). We found that recirculation by this two-needle technique averaged 15.2% and that the technique was insufficiently sensitive to be of value in clinical practice.

Arm↗
PubMed1991

Rate-related recirculation: the effect of altering blood flow on dialyzer recirculation.

Increasing dialyzer blood flow to enhance the efficiency of dialysis has become commonplace. While it is recognized that this procedure may increase recirculation, the resulting extent of recirculation has not previously been examined. We studied 16 patients with various levels of recirculation and found it to average 8.5% at a blood flow of 50 mL/min, 14.9% at 200 mL/min, and 22.5% at 316 mL/min. This rate-related recirculation has a significant impact on dialyzer urea clearance and should be taken into account in the dialysis prescription.

Arteriovenous Shunt, Surgical↗
PubMed1991

Use of thermography for initial detection of early reflex sympathetic dystrophy.

Reflex sympathetic dystrophy is one of a complex of overlapping, sympathetically maintained pain syndromes which are usually initiated by a minor injury that resolves quickly but leaves behind a persistent pain that generalizes to much or all of the limb. The pathophysiology of reflex sympathetic dystrophy is reviewed to show that the pain is accompanied by cooling of the limb, beginning with the distal end and gradually progressing throughout. Thermography is shown to be an effective way to monitor near-surface blood flow in the limbs and to be sensitive to changes accompanying painful conditions. The usefulness of this technique for early detection of reflex sympathetic dystrophy is demonstrated and illustrated with several examples.

Adolescent↗
PubMed1991

Development of an ambulatory recorder for evaluation of muscle tension-related low back pain and fatigue in soldiers' normal environments.

We have developed an ambulatory recorder capable of monitoring low back muscle tension, trunk motion, and ratings of pain and fatigue. It weighs 22 ounces, fits into a canteen belt, and records every second for 18 hours. Eleven subjects wore the recorder during all walking hours for between 3 and 5 days. Six subjects had chronic low back pain due to muscle tension, three experienced low back pain after labor, and two had no pain. Movement and muscle tension correlated highly when subjects were pain free but not when they were in pain. Muscle tension increased before pain was experienced.

Back Pain↗