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Biomedical subjects

R A Sherman

Publications and source records attributed to R A Sherman.

At least 19 recordsLinked to original sources

Modifying the dialysis prescription to reduce intradialytic hypotension.

The dialysis prescription can have a substantial impact on the frequency of intradialytic hypotension (IDH). Plasma volume will decline to a greater extent when the ultrafiltration (UF) rate is rapid (high interdialytic weight gains and/or short treatment time), favoring IDH. The relationship of the target weight to the euvolemic weight determines the size of the interstitial fluid compartment, which is a major determinant of the rate of plasma refilling during UF. The higher the dialysate sodium, the smaller the decline in plasma volume for any given amount of UF. Use of a dialysate temperature that prevents a positive thermal balance during dialysis will allow peripheral vascular resistance to be maintained and minimize IDH. A higher ionized calcium during treatment facilitates an increase in cardiac output, a benefit that may be particularly notable in patients with depressed cardiac ejection fraction. Low dialysate magnesium, potassium, and bicarbonate may all favor IDH, although insufficient data are available for definitive conclusions. The choice of antihypertensive medication and the treatment schedule must be carefully considered in patients with IDH. The future integration of technology to monitor blood pressure, plasma volume, and thermal and sodium balance into a computer-based biofeedback system will very likely go a long way toward reducing the frequency of IDH.

Antihypertensive Agents↗

Maggot débridement therapy in outpatients.

OBJECTIVE: To identify the benefits, risks, and problems associated with outpatient maggot therapy. DESIGN: Descriptive case series, with survey. SETTING: Urban and rural clinics and homes. PARTICIPANTS: Seven caregivers with varying levels of formal health care training and 21 ambulatory patients (15 men, 6 women; average age, 63 yr) with nonhealing wounds. INTERVENTION: Maggot therapy. MAIN OUTCOME MEASURE: Therapists' opinions concerning clinical outcomes and the disadvantages of therapy. RESULTS: More than 95% of the therapists and 90% of their patients were satisfied with their outpatient maggot débridement therapy. Of the 8 patients who were advised to undergo amputation or major surgical débridement as an alternative to maggot débridement, only 3 required surgical resection (amputation) after maggot therapy. Maggot therapy completely or significantly débrided 18 (86%) of the wounds; 11 healed without any additional surgical procedures. There was anxiety about maggots escaping, but actual escapes were rare. Pain, reported by several patients, was controlled with oral analgesics. CONCLUSIONS: Outpatient maggot débridement is safe, effective, and acceptable to most patients, even when administered by nonphysicians. Maggot débridement is a valuable and rational treatment option for many ambulatory, home-bound, and extended care patients who have nonhealing wounds.

Adult↗

Tuberculosis tracking: determining the frequency of the booster effect in patients and staff.

BACKGROUND: Two-step tuberculin skin testing, which is recommended to exclude the booster effect as a cause of converting nonreactive skin test responses to reactive responses, can be expensive and logistically challenging. We studied the booster effect in our patients and staff to determine its frequency and to identify factors that might predict its occurrence. METHODS: Hospital staff members and long-term care patients were given 2-step Mantoux tests and evaluated prospectively. RESULTS: Of 619 staff members tested, the initial tuberculin response was reactive in 39 (6.3%). Of the 97 nonreactive staff members who presented for retesting 6 to 30 days later, 6 were now reactive (6.2%; [95% CI, 2.3%-11.8%]). Twelve (13.6%) of eighty-eight patients were tuberculin reactive on their initial skin test. Of the 37 nonreactive patients appropriately administered their second test, 2 (5.4%, [95% CI, 0.7-18.2%]) were tuberculin-reactive. Thirteen percent of tuberculin-reactive staff members and 16% of tuberculin-reactive patients were identified only after their second skin test. Foreign birth (P =.02) was associated with purified protein derivative response boosting in staff members; anemia was associated with boosting in patients (P =.05). CONCLUSIONS: Our results support 2-step skin testing of all new employees and patients who are likely to receive periodic retesting. In our population, age alone is an inadequate criterion for selecting candidates for retesting.

Age Factors↗

Wound myiasis in urban and suburban United States.

BACKGROUND: The epidemiologic characteristics of human myiasis in the United States remain undefined. OBJECTIVE: To describe the most common clinical conditions associated with human myiasis and the causative maggot species. METHODS: Multicenter, prospective observational study of urban and suburban patients who were infested with maggots. RESULTS: Forty-two cases of US-acquired myiasis were collected from 20 participating centers. Most infestations occurred within preexisting wounds. No cases of tissue invasion were recorded. Host age averaged 60 years, with a male-female ratio of 5.5:1. Homelessness, alcoholism, and peripheral vascular disease were frequent cofactors. Two patients (5%) were hospitalized at the time of their infestation. The most common species was Phaenicia sericata (green blowfly; family: Calliphoridae). Other blowflies, flesh flies (Sarcophagidae), and humpbacked flies (Phoridae) also were identified. In 6 cases, 2 coinfesting species were identified. CONCLUSIONS: Results of this prospective study of myiasis differ significantly from those of our analysis of previously published reports and suggest that most cases of human myiasis are caused by noninvasive blowflies laying eggs in preexisting wounds. Five percent of infestations were nosocomially acquired and not necessarily associated with patient neglect.

Adult↗

Medicinal maggots: an ancient remedy for some contemporary afflictions.

Certain fly larvae can infest corpses or the wounds of live hosts. Those which are least invasive on live hosts have been used therapeutically, to remove dead tissue from wounds, and promote healing. This medicinal use of maggots is increasing around the world, due to its efficacy, safety and simplicity. Given our low cultural esteem for maggots, the increasing use and popularity of maggot therapy is evidence of its utility. Maggot therapy has successfully treated many types of chronic wounds, but much clinical and basic research is needed still. In this review, the biology of myiasis and the history of maggot therapy are presented, the current status of our understanding and clinical use of medicinal maggots is discussed, and opportunities for future research and applications are proposed.

Animals↗

Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique.

UNLABELLED: Measuring total body water in peritoneal dialysis patients using an ethanol dilution technique. BACKGROUND: The accuracy with which total body water (TBW) is estimated is a direct determinant of the reliability of Kt/V urea measurements in peritoneal dialysis (PD) patients. Ethanol dilution has been previously shown to be a reliable measure of TBW. Advances in breath alcohol technology make this a feasible clinical tool. METHODS: We gave 19 fasting chronic PD patients 0.3 g/kg of ethanol (EtOH) orally on two separate occasions. Breath alcohol concentrations (BrACs), determined by dual-beam infrared analysis, were recorded at baseline and periodically thereafter until BrACs were less than 0.01%. The TBW was then determined by standard pharmacokinetic techniques. RESULTS: TBW measurements were reproducible, with a mean between-run difference of -0.004 liter/kg (95% limits of agreement -0.040 to 0. 032 by Bland-Altman). The Watson equations tended to underestimate TBW, with a mean difference (EtOH - Watson) of +3.0 liters (SD 4.0 liters, P = 0.004) and a mean absolute difference of 4.1 liters (SD 2.7 liters, range -4.4 to 9.5 liters). Kt/V was calculated from dialysate and urine collection, using V as determined from TBW estimates from EtOH and Watson. The mean Kt/V(EtOH) was 2.31 (SD 0. 50) compared with 2.46 (SD 0.52) using Watson. The mean absolute difference between the two Kt/V estimates was 0.26 (SD 0.20, range -0.87 to 0.57), with Kt/V overestimated by Watson in 14 patients. EtOH was well tolerated, and the procedure was completed in about four hours. CONCLUSIONS: Measuring V by the BrAC technique does not require blood sampling, is reliable, and is reproducible. It is a potentially useful method for a periodic determination of volume that may allow for more accurate Kt/V measurement in PD patients.

Administration, Oral↗

Treatment of migraine with pulsing electromagnetic fields: a double-blind, placebo-controlled study.

The effect of exposure to pulsing electromagnetic fields on migraine activity was evaluated by having 42 subjects (34 women and 8 men), who met the International Headache Society's criteria for migraine, participate in a double-blind, placebo-controlled study. Each subject kept a 1-month, pretreatment, baseline log of headache activity prior to being randomized to having either actual or placebo pulsing electromagnetic fields applied to their inner thighs for 1 hour per day, 5 days per week, for 2 weeks. After exposure, all subjects kept the log for at least 1 follow-up month. During the first month of follow-up, 73% of those receiving actual exposure reported decreased headaches (45% good decrease, 14% excellent decrease) compared to half of those receiving the placebo (15% worse, 20% good, 0% excellent). Ten of the 22 subjects who had actual exposure received 2 additional weeks of actual exposure after their initial 1-month follow-up. All showed decreased headache activity (50% good, 38% excellent). Thirteen subjects from the actual exposure group elected not to receive additional exposure. Twelve of them showed decreased headache activity by the second month (29% good, 43% excellent). Eight of the subjects in the placebo group elected to receive 2 weeks of actual exposure after the initial 1-month follow-up with 75% showing decreased headache activity (38% good, 38% excellent). In conclusion, exposure of the inner thighs to pulsing electromagnetic fields for at least 3 weeks is an effective, short-term intervention for migraine, but not tension headaches.

Adult↗

Abnormal eating behaviors in military women.

PURPOSE: The purpose of this study was to evaluate the prevalence of abnormal eating behaviors in women on active duty in the Army. METHODS: A total of 423 female soldiers from the general population on active duty volunteered to participate in this study. They completed the Eating Disorder Inventory (EDI) questionnaire. Each questionnaire was screened and any woman on active duty practicing abnormal eating behaviors (criteria set up by the authors) underwent an interview. A diagnosis, using DSM IV criteria, of one of the following was determined from the interview: 1) No eating disorder, (2) Anorexia nervosa, 3) Bulimia nervosa, 4) binge eating disorder, 5a) Eating disorder NOS, and 5b) Situational eating disorder. A situational eating disorder was defined as any abnormal eating behaviors consistent with an eating disorder NOS that was practiced intermittently and in response to external pressures associated with significant distress, such as military weigh-ins or army physical fitness testing (APFT). RESULTS: Of the 423 women on active duty who participated, 33.6% (N = 142) met the questionnaire screening criteria for being "at risk" for abnormal eating behaviors and underwent an interview. Of the 142 women interviewed, 33 (8%) women were diagnosed with an eating disorder. The women with eating disorders exercised, felt dissatisfied with their weight, and felt significantly more pressure about their weight than the women without eating disorders. In addition, they also had significantly greater scores on the Drive for Thinness (DT), Bulemia (B), and Body Dissatisfaction (BD) subscales, and the total EDI scores for both the 8 and 11 subscales. CONCLUSION: In the women on active duty in the Army studied, there was an 8% prevalence of eating disorders.

Adolescent↗

Utilization of prostheses among US veterans with traumatic amputation: a pilot survey.

No random surveys have been done to determine how effectively veterans with amputation can utilize their prostheses, and only one limited survey has been done of Scandinavians' use of lower-limb prostheses. A pilot survey of prosthetic problems was sent to all 170 US veteran soldiers who had traumatic amputations over the last 10 years, whose addresses could be supplied by the VA, and whose medical synopses showed them to be otherwise healthy when leaving the military. This subpopulation was selected as a "best case" group: those most likely to be active, young, and healthy enough to use their prostheses, as well as close enough to the military and veterans medical systems to get adequate treatment. If they have problems, the rest of the veterans with amputation, relatively older and more debilitated, are very likely to have far worse problems. Although only 45 responded (26%), all had significant problems using their prostheses for work. Most problems were related to the attachment method. Even if all nonrespondents were problem free, at least a quarter had very significant problems using their prostheses. This means that there are significant problems with current methods for attaching prostheses that need to be addressed. The first step should be a large survey of veterans with amputation to get an accurate assessment of the extent of prosthesis-related problems.

Amputation Stumps↗

Delusions of ocular parasitosis.

PURPOSE: To describe four cases of delusions of parasitosis in which self-inflicted ocular trauma occurred. Delusions of parasitosis is a somatic delusional disorder in which patients have the irrational belief that their bodies are infested by parasites or other infectious organisms. Self-inflicted trauma can result from attempts to eliminate the supposed infestation. METHODS: We reviewed the case histories of four patients (one male, three females, 35 to 45 years of age) who presented with complaints of ocular infestation but had no evidence of infectious ocular disease. The characteristics of these cases were compared with the features of delusions of parasitosis. RESULTS: All patients maintained their beliefs regarding infestation, despite extensive clinical and laboratory investigations that found no evidence of infectious diseases. Self-inflicted eye injury, associated with attempts to eliminate the infestation, occurred in each case. CONCLUSIONS: The cases presented in this report are consistent with a diagnosis of delusions of parasitosis. The eye can be a principal focus of attention in this disorder, which may lead to vision loss caused by self-inflicted injury.

Adult↗

Initial exploration of pulsing electromagnetic fields for treatment of migraine.

Two studies were conducted during which 23 patients with chronic migraine were exposed to pulsing electromagnetic fields over the inner thigh. In an open study, 11 subjects kept a 2-week headache log before and after 2 to 3 weeks of exposure to pulsing electromagnetic fields for 1 hour per day, 5 days per week. The number of headaches per week decreased from 4.03 during the baseline period to 0.43 during the initial 2-week follow-up period and to 0.14 during the extended follow-up which averaged 8.1 months. In a double-blind study, 9 subjects kept a 3-week log of headache activity and were randomly assigned to receive 2 weeks of real or placebo pulsing electromagnetic field exposures as described above. They were subsequently switched to 2 weeks of the other mode, after which they kept a final 3-week log. Three additional subjects in the blind study inadvertently received half-power pulsing electromagnetic field exposures. The 6 subjects exposed to the actual device first showed a change in headache activity from 3.32 per week to 0.58 per week. The 3 subjects exposed to only half the dose showed no change in headache activity. Large controlled studies should be performed to determine whether this intervention is actually effective.

Adult↗

Pharmacokinetics of intraperitoneal fluconazole during continuous cycling peritoneal dialysis.

OBJECTIVE: To investigate the pharmacokinetic characteristics of intraperitoneal fluconazole in patients undergoing continuous cycling peritoneal dialysis (CCPD). DESIGN: Prospective, nonrandomized, single-dose, open-label study. PARTICIPANTS: Five noninfected volunteer CCPD patients. INTERVENTIONS: Patients received a single dose of intraperitoneal fluconazole 200 mg during their long daytime dwell. Blood samples were collected before and 1, 3, 6, 12 (end of first dwell), 24 (after overnight cycling), 48, 72, 96, and 120 hours after dosing. Used dialysate was collected throughout the study. Unless the patient was anuric, urine was collected for the first 48 hours. MAIN OUTCOME MEASURE: Fluconazole concentrations were assayed by gas-liquid chromatography. Pharmacokinetic parameters were calculated using standard noncompartmental techniques. RESULTS: The bioavailability of intraperitoneal fluconazole was 96% +/- 2% over a 12-hour dwell, absorption half-life was 2.5 +/- 1.2 hours, serum elimination half-life was 71.65 +/- 12.76 hours, and volume of distribution was 0.66 +/- 0.13 L/kg. Peritoneal clearance was 5.96 +/- 0.93 mL/min and proportional to total dialysate volume. Renal clearance was proportional to renal creatinine clearance. CONCLUSIONS: Current treatment guidelines for fungal peritonitis suggest fluconazole 200 mg intraperitoneally every 24 hours. Our data suggest that this dose, administered every 48 hours, is more than sufficient to maintain serum and peritoneal concentrations above the minimum inhibitory concentration for most Candida spp. Other factors, such as residual renal function and dialysis prescription, may also need to be considered.

Adult↗

Simplified measurement of intra-access pressure.

The measurement of intra-access pressure (P[IA]) normalized by mean arterial BP (MAP) helps detect venous outlet stenosis and correlates with access blood flow. However, general use of P(IA)/MAP is limited by time and special equipment costs. Bernoulli's equation relates differences between P(IA) (recorded by an external transducer as PT) and the venous drip chamber pressure, PDC; at zero flow, the difference in height (deltaH) between the measuring sites and fluid density determines the pressure deltaPH = P(IA) - P(DC) Therefore, P(DC) and PT measurements were correlated at six different dialysis units, each using one of three different dialysis delivery systems machines. Both dynamic (i.e., with blood flow) and static pressures were measured. Changes in mean BP, zero calibration errors, and hydrostatic height between the transducer and drip chamber accounted for 90% of the variance in P(DC), with deltaPH = -1.6 + 0.74 deltaH (r = 0.88, P < 0.001). The major determinants of static P(IA)/MAP were access type and venous outflow abnormalities. In grafts, flow averaged 555 +/- 45 ml/min for P(IA)/MAP > 0.5 and 1229 +/- 112 ml/min for P(IA)/MAP < 0.5. DeltaPH varied from 9.4 to 17.4 mmHg among the six centers and was related to deltaH between the drip chamber and the armrest of the dialysis chair. Concordance between values of P(IA)/MAP calculated from PT and from P(DC) + deltaPH was excellent. It is concluded that static P(DC) measurements corrected by an appropriate deltaPH can be used to prospectively monitor hemodialysis access grafts for stenosis.

Arteriovenous Shunt, Surgical↗

Pharmacokinetics of vancomycin when administered during high flux hemodialysis.

This study was undertaken to evaluate the pharmacokinetics of relatively high-dose vancomycin when administered during high-flux hemodialysis using a polysulfone membrane (F-80, Fresenius). Five noninfected, anuric patients received a single dose of 25 mg/kg of vancomycin infused during hemodialysis at a rate of one gram per hour and timed such that the end of the infusion coincided with the end of dialysis. Blood samples were drawn during the infusion, up to six hours after the end of dialysis and then prior to the next three dialysis treatments. Spent dialysate was collected during the infusion. Samples were analyzed using the EMIT assay. The percent of vancomycin lost during the first dialysis session ranged from 39.1 to 55.1% (mean, 45.7+/-6.4). The concentration of vancomycin at 6 hours after hemodialysis ranged from 18.2 to 45.1 mg/L (mean, 29.6+/-10.0 mg/l). Dialysis clearance ranged from 96.1 to 158.1 ml/min (mean, 130.7 +/-30.0 ml/min). One week after dosing, serum concentrations ranged from 8.14 mg/l to 10.1 mg/l (mean, 9.0+/-1.0 mg/l). This study suggests than an initial dose of 25 mg/kg of vancomycin, given during high-flux dialysis, may provide adequate serum concentrations in anuric hemodialysis patients for up to seven days. This dosing scheme reduces inconvenience to the patient and staff, and potentially can reduce nursing costs associated with post-dialysis administration; its cost is minimal. At this point, subsequent dosing is best determined by therapeutic drug monitoring.

Adult↗

Recirculation, urea disequilibrium, and dialysis efficiency: peripheral arteriovenous versus central venovenous vascular access.

When accurate, non-urea-based methods of measuring recirculation are used, recirculation is usually absent in arteriovenous (AV) accesses. When urea-based methods are used to measure recirculation in AV accesses, falsely elevated recirculation rates are common. These errors are due to AV and venovenous disequilibrium (peripheral vein method), delayed systemic sampling (two-needle methods), and errors in urea measurement (all methods). The literature suggests that recirculation in central venovenous (CV) catheters is approximately 5%. The methods used for these determinations have all been urea based. However, there are few theoretical problems in using urea-based measurements for measuring recirculation in this setting, making it more likely that these values are accurate. When hemodialysis via CV and AV accesses are compared, equilibrated Kt/V values differ significantly for the same single-pool Kt/V when 15-second postdialysis blood urea nitrogen values are used for modeling, but differ minimally when 2-minute postdialysis samples are used. The impact of transient retrograde blood flow in the superior vena cava on recirculation and whether dialysis efficiency is influenced by the exact site of CV catheter placement (superior vena cava v right atrium) is uncertain.

Blood Circulation↗