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Biomedical subjects

W T Edwards

Publications and source records attributed to W T Edwards.

52 records · Page 3Linked to original sources
PubMed1989

Effects of physical activity on maternal plasma beta-endorphin levels and perception of labor pain.

Thirty-six women in their second or third pregnancies were studied in two groups (control and exercise) to determine whether plasma alpha-endorphin levels could be elevated by exercise conditioning during pregnancy. Aerobic training was performed on a bicycle ergometer. Both groups were monitored throughout pregnancy by frequent gynecologic examinations. During labor, both groups of women had pain perception assessment. Blood was sampled for levels of beta-endorphin, cortisol, human growth hormone, and prolactin. Plasma beta-endorphin was found elevated compared to controls in patients who exercised throughout pregnancy. This difference was maintained throughout labor and pain perception during labor was reduced in the patients who exercised. Cortisol, human growth hormone, and prolactin levels were lowered during labor for the exercise-conditioned patients. Exercise conditioning during pregnancy seems to be beneficial in reducing pain perception during labor (as determined by measurement of visual analog pain scales) and in reducing stress levels during labor.

Arm↗
PubMed1989

In vitro spinal arthrodesis implant mechanical testing protocols.

Mechanical testing protocols and test methods used to evaluate spinal implants have varied widely. Use of different test methods would not present a problem except that multicomponent mechanical systems, such as the spine and spinal implant constructs, yield different mechanical properties when subjected to different test methods. The goal of this article is to outline considerations specific to the mechanical assessment of spinal implants. With standard test methods and treatment of results, redundancy between testing programs will be reduced and comparison of results will be facilitated.

Biomechanical Phenomena↗
PubMed1987

Variation of lumbar spine stiffness with load.

Mechanical studies of the Functional Spinal Unit (FSU) in-vitro have shown that the slopes of the load-displacement curves increase with load. This nonlinearity implies that the stiffness of the FSU is not constant over the range of physiologic loads, and that measurements obtained for FSU specimens through the application of individual loads cannot be summed to predict the response of the specimens to combined loads. Both experimental and analytical methods were developed in the present study to better quantify the nonlinear FSU load-displacement response and to calculate the coupled stiffness of FSU specimens at combined states of load reflecting in-vivo conditions. Results referenced to the center of the vertebral body indicate that lumbar FSU specimens are stiffer in flexion than in extension, and that FSU specimens loaded in flexion are stiffer at high loads than at low loads. The importance of combined load testing and a nonlinear interpretation of load-displacement data is demonstrated.

Biomechanical Phenomena↗
PubMed1985

Prediction of vertebral body compressive fracture using quantitative computed tomography.

We performed quantitative computed tomography in vitro on the first and third lumbar vertebrae in human cadavera using a dibasic potassium phosphate phantom for calibration. The quantitative computed-tomography numbers exhibited a significant positive correlation (R2 = 0.89, p less than 0.0001) with direct measurements of the apparent density of the vertebral trabecular bone. We also conducted uniaxial compression tests to failure of the vertebral bodies after removal of the posterior elements, and found that vertebral compressive strength was also correlated at a high level of significance (R2 = 0.82, p less than 0.0001) with direct measurement of the trabecular apparent density. These findings suggested the possibility that the quantitative computed-tomography values might be directly predictive of vertebral compressive strength. However, when we correlated the quantitative computed-tomography values directly with vertebral compressive strength, the results (R2 = 0.46, p less than 0.061) were suggestive but not quite significant. All vertebral bodies failed by compression of the end-plate, suggesting only a modest structural role for the cortical shell under these loading conditions. This was confirmed by comparing the compressive load to failure of twenty additional pairs of vertebrae that were tested with and without an intact vertebral cortex. Removal of the cortex was associated with approximately 10 per cent reduction in vertebral load to failure.

Aged↗
PubMed1983

Multicenter clinical evaluation of long-term efficacy and safety of labetalol in treatment of hypertension.

The long-term efficacy and safety of labetalol, an antihypertensive agent with combined beta- and alpha-blocking activity, were evaluated alone (number = 193) and in combination with a diuretic (number = 144) in an open-label multicenter trial of 337 hypertensive patients aged 21 to 75 years, including initially 205 (61 percent) men and 219 (65 percent) Caucasians. There were 219 (65 percent) mild, 85 (25 percent) moderate, and 33 (10 percent) severe hypertensive patients. Labetalol (100 to 1,200 mg twice a day) alone or in combination with a diuretic reduced the mean standing blood pressure by 13/11 and 25/16 mm Hg to 135/88 and 130/91 mm Hg, respectively (p less than 0.01), and supine blood pressure by 6/7 and 18/13 mm Hg to 141/86 and 138/90 mm Hg (p less than 0.01), respectively. Blood pressure reductions observed at one month were maintained after one year; 206 (62 percent) patients had 10 mm Hg or greater reductions and 184 (56 percent) patients were maintained at diastolic blood pressures less than 90 mm Hg. Most frequently reported drug-related side effects included fatigue (14 percent), dizziness (12 percent), nausea (11 percent), nasal stuffiness (8 percent), headache (4 percent), and male sexual dysfunction (14 percent). Side effects were generally of mild to moderate intensity and often transient. In addition, in 27 (8 percent) patients reversible asymptomatic transaminase elevations to greater than twice normal developed at some time during the study. In 13 (4 percent) patients these alterations resolved during continued labetalol therapy, but in five (2 percent) patients these marked elevations led to discontinuation of the drug. A total of 32 (9.5 percent) patients were terminated prematurely due to side effects (most commonly genitourinary or gastrointestinal) possibly attributable to the drug. These findings indicate that labetalol with or without a diuretic is a potentially effective, safe, and relatively well-tolerated long-term antihypertensive therapy.

Adult↗
PubMedDate not supplied

Anesthesia-assisted procedures in a burn intensive care unit procedure room: benefits and complications.

A retrospective review of 109 procedures was performed to evaluate the safety and efficacy of anesthesiologist-administered anesthesia in the burn intensive care unit treatment room. Intraprocedural and postprocedural complications, impact on patient activity, and nutritional goals were evaluated. The review suggested that these procedures can be performed safely with appropriate supervision and monitoring without detrimental effects on patient activity level or nutritional status.

Adult↗
PubMedDate not supplied

A comparison of oral transmucosal fentanyl citrate and oral hydromorphone for inpatient pediatric burn wound care analgesia.

The ideal oral wound care analgesic for children should be palatable, provide potent analgesia of rapid onset and short duration, and require minimal, yet appropriate, monitoring. With use of a double-blinded crossover design, we compared the efficacy and safety of oral transmucosal fentanyl citrate (OTFC) (approximately 10 micrograms/kg) with the efficacy and safety of oral hydromorphone (60 micrograms/kg) in 14 pediatric inpatients (ages 4 to 17 years) undergoing daily burn wound care in a ward setting. Pulse oximetry, vital signs, side effects, patient pain scores, and observer scores for cooperation, anxiety, and sedation were recorded. Pulse oximetry, vital signs, cooperation, sedation, incidence of nausea or vomiting, and the amount of time it took to resume normal activities were similar in both treatment groups. OTFC resulted in improved pain scores before wound care and improved anxiolysis during wound care, but at other points it was similar in effect to hydromorphone. We conclude that OTFC is a safe and effective analgesic, that it may provide minor improvements in analgesia and anxiolysis compared with hydromorphone, and that it offers a palatable alternative route of opioid administration without intravenous access for wound care procedures in children.

Administration, Oral↗
PubMedDate not supplied

Facial trauma and 3-D reconstructive imaging: insufficiencies and correctives.

PURPOSE: To address the clinical relevance of and optimal technique for 3-D CT imaging of facial trauma. METHODS: Bioengineered cadaveric models were developed to enhance the concepts of LeFort. Diverse CT imaging techniques were applied to obtain optimal data sets for processing on various 3-D workstations. The fidelity of the 3-D reconstructions was determined by comparison with photographs of the cadaveric models. Optimized 3-D images were then used in conjunction with the initial 2-D data sets to assess whether additional accuracy was contributed by the 3-D images in the evaluation of modeled facial fractures. RESULTS: Image definition was heavily dependent upon the specific 3-D reconstruction algorithm and the processor utilized. Orbital fractures were best imaged when 1- to 1.5-mm coronal sections were processed on an advanced 3-D workstation. The 3-D CT images resulted in additional accuracy in the 2-D CT evaluation of facial fractures in 29% of trials. CONCLUSIONS: We believe that bioengineered models of facial trauma--matched with appropriate CT scanning parameters--facilitate graphically reliable 3-D reconstructive imaging. 3-D reconstructions can improve accuracy in the 2-D CT evaluation of facial trauma.

Algorithms↗