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Biomedical subjects

E Simmons

Publications and source records attributed to E Simmons.

At least 19 recordsLinked to original sources
PubMed1995

Does out-of-hospital EMS time affect trauma survival?

To determine if out-of-hospital emergency medical services (EMS) time intervals are associated with unexpected survival and death in urban major trauma, a retrospective review was conducted of major trauma cases entered into an urban trauma system by an EMS system during a one-year period. Patients with unexpected death or unexpected survival were identified using TRISS methodology. The EMS response, on-scene time, transport time, and total EMS out-of-hospital time intervals were compared for the two groups using the unpaired t test (two-tailed analysis). Of 848 major trauma cases, there were 13 (1.5%) unexpected survivors and 20 (2.4%) unexpected deaths. Of those patients with complete EMS times, the mean out-of-hospital response time interval was significantly shorter for the unexpected survivors (3.5 +/- 1.2 minutes v 5.9 +/- 4.3 minutes; P = .04). The mean EMS on-scene time interval (7.8 +/- 4.1 minutes v 11.6 +/- 6.5 minutes; P = .06) and the mean transport time interval (9.5 +/- 4.4 minutes v 11.7 +/- 4.0 minutes; P = .17) also favored the unexpected survivor group. Overall, the total EMS time interval was significantly shorter for unexpected survivors (20.8 +/- 5.2 minutes v 29.3 +/- 12.4 minutes; P = .02). It was concluded that a short overall out-of-hospital time interval may positively affect patient survival in selected urban major trauma patients.

Adolescent↗
PubMed1995

Paramedic injury severity perception can aid trauma triage.

STUDY OBJECTIVE: To compare information contained in standard out-of-hospital trauma triage criteria and standard criteria plus advanced emergency medical technician (EMT) injury severity perception for determination of patient need for trauma center evaluation. DESIGN: Prospective, observational cohort analysis of trauma triage by advanced EMTs. PARTICIPANTS: Out-of-hospital, geographically stratified statewide sample of patients injured in Oregon. RESULTS: Advanced EMTs provided patient information on demographics, physiologic parameters, injury anatomy and mechanism, premorbid conditions, EMT injury severity perception, and trauma system entry status. A four-point scale was used to grade the injury severity perception. Need for trauma center evaluation was defined as major surgery within 6 hours of hospital arrival, admission to the ICU, death in the hospital, or Injury Severity Scale score of 16 or more. The relative triage information gain with injury severity perception was assessed by use of logistic regression, tree-based models, and receiver operating characteristic (ROC) curves. Of 1,063 patients, 307 (28.9%) warranted trauma center evaluation. With logistic regression modeling, the following standard triage parameters were associated (P < .05) with the need for trauma center evaluation after inclusion of injury severity perception: systolic blood pressure less than 90 mm Hg, abnormal respiratory rate (less than 10 or more than 29), Glasgow Coma Scale score less than 13, penetrating injury (midthigh to head), two or more obvious proximal long-bone fractures, and fall of more than 20 feet. The two largest injury severity perception categories had the greatest odds ratios (20:1 and 167:1). ROC curve areas improved with injury severity perception (.88 versus .83 without; P < .0001). CONCLUSION: Standard out-of-hospital triage criteria benefit from inclusion of advanced EMT injury severity perception information.

Emergency Medical Technicians↗
PubMed1995

Intracity regional demographics of major trauma.

STUDY OBJECTIVE: To report intracity, regional trauma, geographic, and demographic factors affecting risk of major intentional versus nonintentional trauma. DESIGN: One-year retrospective analysis of trauma-registry and census-tract databases. SETTING: Urban trauma system with patient entry by emergency medical services personnel. PARTICIPANTS: Major trauma cases grouped by presumed intent to injure. INTERVENTIONS: We examined age- and sex-adjusted trauma rates for seven geographic intracity regions (comprising of 144 census tracts) to identify associations with population density, median household income, and race data. Rates and risk factors for intentional versus nonintentional trauma were compared. RESULTS: Two hundred fifty-seven intentional and 575 nonintentional major trauma system cases were identified. Both intentional (relative risk [RR], 7.0; 95% CI, 5.1 to 9.7) and nonintentional (RR, 2.7; CI, 2.3 to 3.3) injury populations were predominately male. Intentional-trauma victims were disproportionately nonwhite (RR, 4.1; CI, 3.2 to 5.1). The 15- to 24-year-old (RR, 20.3; CI, 16.7 to 24.6) and 25- to 34-year-old (RR, 15.3; CI, 12.7 to 18.4) age groups were more likely to sustain intentional trauma than the 0- to 14-year-old age group. Regional differences in occurrence rates were most pronounced for intentional trauma; 52% of all intentional traumas occurred within a small area of 14 census tracts. Residents in low median income households were more commonly subject to intentional injury. CONCLUSION: Different demographic features affect intentional and nonintentional major trauma in Portland, Oregon. These features can be used to guide emergency medical services planning and injury-prevention measures.

Accidents, Traffic↗
PubMed1995

A new porous surface modification technology for peritoneal dialysis catheters as an exit-site cuff to reduce exit-site infections.

Catheter exit-site infection continues to be a more common morbid event in patients undergoing peritoneal dialysis. Previous attempts to place a biointegration material at the next site have failed to reduce infection rates. This study reports the use of an innovative microporous silicone material placed as a cuff around the catheter at the exit site. The porous material has a pore-sized distribution that stimulates and facilitates capillary ingrowth into the pores. This capillary ingrowth prevents scar tissue formation, increases blood supply, and theoretically improves the immunological competence of the tissue at the vulnerable exit site. Twenty-five test catheters (12 using standard exit-site creation and 13 using the Moncrief-Popovich implantation technique) were implanted in a canine model. The exit-site infection rate in a canine model without the microporous material was 100% at 2 months. The corresponding results with the microporous material was 40% at 2 months. The majority of the test catheters showed progressive drying and healing at the exit site. Sixty percent of the catheters healed quickly and remained infection-free. Biointegration of the microporous material at the exit-site was demonstrated. Several exit site infections with the test catheters treated only with local therapy (without systemic or topical antibiotics) demonstrated progressive healing and secondary adequate biointegration. Because of these encouraging results, human studies were initiated, with the first human implant occurring in August, 1994. A 10-patient project is planned for the next year.

Animals↗
PubMed1993

Catheter obstruction with omental wrap stimulated by dialysate exposure.

A new implantation technique and catheter design (Moncrief-Popovich Catheter) were tested in the continuous ambulatory peritoneal dialysis (CAPD) dog model. With this technique the catheter distal (external) segment was implanted in a subcutaneous tunnel for 4-6 weeks. Therefore, no irrigation of exposure to dialysate was present. Secondary exteriorization and irrigation (CAPD exchanges) demonstrated no episodes of primary catheter obstruction. Fifteen mongrel female dogs had 30 catheters implanted; 2 catheters simultaneously in each dog. One catheter was implanted with the interabdominal segments in the pelvis and the second interabdominal segment directed upward in direct contact with the omentum. Following initial irrigation, all catheters were patent, but within 24-48 hours all upwardly directed catheters were obstructed. Nine of the 15 downwardly directed catheters became obstructed by omentum wrapping around the catheter within 5 days. Preliminary studies have failed to demonstrate the cause of this "omental stimulation," which occurs with peritoneal contact with fresh dialysate. Possible explanations include pH, osmolality, flow direction, volume, vasodilator effect of osmols or lactate, and glucose, among others. This effect needs study, and this model would allow evaluation of improvements in the biocompatibility of dialysis fluids.

Animals↗
PubMed1993

Reduction in peritonitis incidence in continuous ambulatory peritoneal dialysis with a new catheter and implantation technique.

Recurrent episodes of peritonitis with the same organism cultured at the catheter exit site suggest that early tunnel colonization is associated with a transfer of these organisms through the catheter tunnel directly from the skin into the peritoneal cavity. In this instance the catheter has failed in its fundamental design to establish and maintain a bacteriological barrier. A three-part study was conducted using the Moncrief-Popovich catheter and implantation technique. The first part of the study included 59 patients who used standard spike exchange systems with this new catheter and implantation technique. A reduction in the incidence of peritonitis occurred in the continuous ambulatory peritoneal dialysis (CAPD) program at the Austin Diagnostic Clinic. The previous peritonitis incidence was 1 every 9 patient-months. This study had 1 every 29 patient-months with 530 patient-months of experience. The second part of the study had 79 patients. All except 11 used disconnect exchange systems. There was a total of 482 patient-months of experience with 1 episode every 27 patient-months. Those using the disconnect systems (86%) had 1 episode every 32 patient-months. The third part of the study included microscopic studies of 12 excised catheters. Three were known to be contaminated. The examiners identified those catheters that were free or nearly free of biofilm on the catheter segment between the two cuffs. It is concluded that biofilm analysis and reduction in peritonitis incidence supports the theory that the new catheter and implantation technique form an improved bacteriological barrier in the access for peritoneal dialysis.

Catheterization↗
PubMed1992

Patella alta and recurrent dislocation of the patella.

Fifteen knees were treated with a surgical technique designed for recurrent patellar dislocations when associated with patella alta. The average number of patellar dislocations preoperatively was 12, and the determination of patella alta was made using the technique described by Insall and Salvati, which is a ratio of the length of the patellar tendon to the longest diagonal length of the patella. The normal value for this ratio is 1.02 plus or minus 20%. The average preoperative ratio in this study was 1.58 (range, 1.2-2.1), which changed to 1.08 (range, 0.99-1.14) by the time of follow-up examination. The surgical technique used involves transposing the patellar tendon insertion distally without any medialization or recessing and allows for good bone contact for healing, secure fixation, and immediate postoperative motion. There were no recurrences of patellar dislocation postoperatively and few complications. Only one patient complained of anterior knee pain in the follow-up period. This technique is thought to give good results when it is used specifically for recurrent patellar dislocations associated with patella alta.

Adolescent↗
PubMed1989

Immunoregulatory activity in supernatants from cultures of normal human trophoblast cells of the first trimester.

Supernatants from isolated trophoblast cell cultures (trophoblastic fluid) derived from first-trimester human placentas were assessed for immunoregulatory activity. Trophoblastic fluid at different days of culture consistently inhibited the blast transformation of allogenic lymphocytes. This suppressor effect had no apparent correlation with biosynthesis of human chorionic gonadotropin by trophoblast cells, since this hormone was secreted into the culture fluid only for the initial 3 days. However, the culture fluids of such purified trophoblast cells contained an immunosuppressive factor, pregnancy-associated plasma protein A, which was measurable throughout the culture period of 8 days. The presence of pregnancy-associated plasma protein A in significant amounts in trophoblastic fluid collected at daily intervals indicated a continuous secretion ability of pregnancy-associated plasma protein A by trophoblast cells in culture parallel to the suppressive immunoregulatory effect of the fluid. Such immunosuppressive effect was absent in the culture fluids of control BeWo malignant trophoblast cells; the BeWo cell culture fluids had markedly reduced levels of pregnancy-associated plasma protein A. The culture supernatant of normal trophoblast cells of placentas from first-trimester pregnancy activated in vitro the generation of a population of suppressor lymphocytes. This effect is generally considered responsible for immunologic tolerance. Therefore demonstration of immunosuppressive effects and the presence of relatively high levels of pregnancy-associated plasma protein A in trophoblastic fluid indicate that such proteins secreted by the trophoblast cells may be important in the local immunoregulatory processes of the fetal allograft.

Cells, Cultured↗