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Biomedical subjects

A Fast

Publications and source records attributed to A Fast.

46 records · Page 3Linked to original sources

The weight relieving walker-scooter (WRWS or Robi-Roller): a new walking aid for outdoor life.

Patients suffering from the restriction of their locomotor function due to disease of the weight-bearing joints or ischaemic intermittent claudication, but who are otherwise relatively healthy, are enabled to achieve a remarkable improvement in the quality of their lives by the use of a new weight-relieving walker-scooter. The device is described. Simple experiments using the walker-scooter are recorded. The importance of ambulation is stressed, and the place of various walking aids is discussed.

Humans↗

Reflex sweating in patients with spinal cord injury: a review.

Sweat glands derive their innervation from the sympathetic nervous system. The spinal sympathetic structures that are located in the intermediolateral areas extend from T1-L2 segments and are under the control of hypothalamic centers. Cord transection abolishes the supraspinal control of sudorimotor function. Since sympathetic innervation does not follow a clear segmental distribution, normal sweating may be preserved at a higher or lower level than skin sensation. Nonthermoregulatory reflex sweating is an indication of unchecked spinal cord facilitation and is precipitated by afferent stimuli from bladder, rectum, and various other sources. It is usually a manifestation of mass reflex or autonomic crisis and occurs particularly in cervical or high thoracic lesions. Transection below T8-T10 is not accompanied by reflex sweating. The phenomenon of thermal relfex sweating is controversial. Although some aspects of nonthermoregulatory reflex sweating are still unclear, proper immediate and continuing preventive management will reduce the incidence of this and other autonomic manifestations. Chemical sympathectomy should be a last resort in case of emergency or when the source of facilitation cannot be ascertained.

Autonomic Nervous System↗

Cardiopulmonary complications in multicentric reticulohistiocytosis. Report of a case.

Multicentric reticulohistiocytosis (MR) is a rare disease. Only recently was its systemic nature appreciated. It affects the skin, mucous membranes, joints, muscles, tendon sheaths, synovial membranes, bones, liver, kidney, lymph nodes, heart, and lungs. Our patient, a 50-year-old woman, had life-threatening cardiopulmonary complications of MR. The connection between the skin lesions, the arthritis, and the pathologic changes in the heart and lungs is still obscure.

Adult↗

Forces, moments, and accelerations acting on an unrestrained dummy during simulations of three wheelchair accidents.

To determine the magnitude and distribution of the forces, moments, and accelerations acting on an individual sitting in a wheelchair during three possible accidents occurring while negotiating a sidewalk curb, experimental trials were performed in a bioengineering laboratory using a 50th percentile Hybrid III dummy seated in a standard wheelchair. A ramp was designed with an adjustable incline to allow the wheelchair to reach the edge of a sidewalk height platform at the desired forward speed of 2.5 miles per hour (comfortable walking speed). The wheelchair velocity was monitored via an optical pickup. Three types of accidents were simulated: (1) a wheelchair hitting straight into a curb; (2) a wheelchair falling forward straight off a curb; (3) a wheelchair falling diagonally off a curb. Each experiment was repeated three times. Each run was photographed using high-speed cameras and videotaped from three perspectives: frontal, lateral, and overhead. The results were averaged and compared with published injury Assessment Values (IAV) and Head Injury Criteria (HIC). Of significance were the following results. In the straight into a curb experiments, the wheelchair remained upright and the dummy seated. Low magnitude forces (23-73 N), moments (1-12 Nm), and accelerations (0.2-1 G) were recorded at the neck and head. The HIC was low at 0.3. These results were of no clinical significance. In the straight off a curb experiments, properly attached footrests prevented the wheelchair from toppling over but did not prevent the dummy from falling off the wheelchair. Forces (187-4,176 N), moments (3-178 Nm), and accelerations (131-206 G) of great magnitude were recorded at the head and neck when the dummy fell off the wheelchair. These values were above IAV. The HIC was 960. In the diagonally off a curb experiments, both the wheelchair and the dummy fell sideways. High-magnitude forces (274-2,313 N), moments (4-110 Nm), and acceleration (140-236 G) were recorded in the head and neck regions. The HIC was 975. These values were close to IAV and may signify potential serious injuries.

Acceleration↗

Forces, moments, and acceleration acting on a restrained dummy during simulation of three possible accidents involving a wheelchair negotiating a curb: comparison between lap belt and four-point belt.

The objective of this study was to determine the effect of two types of restraining belts (lap belt and a four-point belt) on an instrumented dummy during three situations: wheelchair hitting straight into curb (SIC); wheelchair falling straight off a curb (SOC); wheelchair falling diagonally off a curb (DOC). A fully instrumented (50th percentile Hybrid III) dummy was seated in a standard wheelchair and restrained with one of the belts. The wheelchair rolled down a ramp reaching a platform at 2.4 miles per hour (comfortable walking speed). Three types of experiments were performed: SIC, SOC, DOC. Each experiment was repeated at least three times. Forces, moments, and acceleration were monitored and recorded via 48 sensors placed at the head, spine, and limbs. All experiments were videotaped and photographed. The data were averaged and compared with standards that have been previously established in car crash testing and with data recently obtained in a similar study using a nonrestrained dummy. Our results showed that in the SIC experiments, low magnitude forces, moments, and acceleration of no clinical significance were recorded with both types of belts. The wheelchair remained upright and the dummy safely seated. In the SOC experiments, the two belts prevented the dummy's ejection from the chair and, thus, have been effective in lowering the forces, moments, and acceleration and preventing significant injuries to the head and neck regions. In the DOC experiments, the lap belt proved to be somewhat more effective than the four-point belt in lowering the extension forces at the upper neck and the moments at the lower neck below injury levels. It also kept the head injury criteria well below injury level. We postulate that the four-point belt was less effective because of its more extensive body fixation, which leads to concentration of moments and forces at the head and lower neck regions. The results of this study show that restraining systems can enhance the safety of wheelchair occupants in certain incidents. It has been demonstrated that the lap belt is as effective as the four-point belt system in SIC and SOC incidents. In DOC falls, neither belt could prevent falls and trauma to the head and neck region. The lap belt, however, was somewhat superior. We recommend that wheelchairs be equipped with a lap belt and patients be encouraged to buckle-up while using the wheelchair outdoors.

Acceleration↗

One step forward and two steps back: the dangers of walking backwards in therapy.

Walking backwards has been used in therapy to improve balance and gait. There has not been any systematic investigation into the effectiveness or safety of walking backwards. We present two cases in which walking backwards during physical therapy resulted in a fall and considerable morbidity. The only clear indication for treatment by walking backwards should be a task-specific need to do so, and only then if adequate safety can be assured.

Accidental Falls↗

Nocturnal low back pain in pregnancy: polysomnographic correlates.

Thirteen women in late stages of pregnancy underwent a polysomnographic study. Eight women (61%) complained of mild nocturnal back pain or back discomfort. Five women (39%) did not complain of nocturnal back pain. The two groups did not differ in total bed time, total sleep time, sleep latency, and wake after sleep onset (WASO). A significant decrease in rapid eye movement (REM) sleep and an increase in stage 2 were observed in the pain group. The same group had a statistically significant decrease in the basal O2 saturation level. The pain group also spent a longer time sleeping in the supine position. We hypothesize that a prolonged stay in the supine position leads to obstruction of the vena cava. In the presence of inadequate collateral circulation, increased pressure and venostasis in combination with a decrease in basal oxygen saturation may lead to hypoxemia, compromise the metabolic supply of the neural structures, and result in pain. It appears, therefore, that the vascular system plays an important role in the pathogenesis of pain. The role played by the disturbed sleep architecture in the production of pain remains to be established. It is possible that the changes observed in sleep architecture result from pain rather than contribute to pain production.

Adult↗