Comparison of test characteristics of urine dipstick and urinalysis at various test cutoff points.

STUDY OBJECTIVE: We compare the test characteristics of urine dipstick and urinalysis at various test cutoff points in women presenting to emergency departments and an intermediate care center with symptoms of urinary tract infection. METHODS: This was a prospective, observational study of adult women presenting to 1 of 2 community hospital EDs or an intermediate care center with dysuria, urgency, or urinary frequency on history, or suprapubic or costovertebral angle tenderness on examination. Patients who had taken antibiotics in the past 72 hours, had indwelling Foley catheters, symptomatic vaginal discharge, diabetes mellitus, immunodeficiency disorders, or were unable to provide a reliable history were excluded. The patient's clean-catch or catheterized urine specimen was tested immediately by a nurse using a Multistix 9 SG reagent strip. A second aliquot was sent within 1 hour of collection to the hospital laboratory, where a semiautomated microscopic urinalysis and a urine culture were performed. A positive urine culture was defined as more than 100,000 colonies of 1 or 2 uropathogenic bacteria per mL of urine at 48 hours. Dipstick and urinalysis data were compared with urine culture results. Sensitivity, specificity, and predictive values were calculated at various definitions of a positive test, or "test cutoff points," for combinations of leukocyte esterase, nitrite, and blood on dipstick and for RBCs and WBCs on urinalyses. The probability of an erroneous decision to withhold treatment on the basis of a negative test result was defined as "undertreatment," or 1 minus the negative predictive value. "Overtreatment" was defined as 1 minus the positive predictive value. RESULTS: Three hundred forty-three patients were enrolled in this study. Twelve patients were withdrawn because of missing laboratory results. Forty-six percent (152/331) of patients had positive urine cultures. If urine dipstick results are defined as positive when leukocyte esterase or nitrite is positive or blood is more than trace, the overtreatment rate is 47% (156/331) and the undertreatment rate is 13% (43/331). If urinalysis results are defined as positive when WBCs are more than 3 per high-power field or RBCs are more than 5 per high-power field, the overtreatment rate is 44% (146/331) and the undertreatment rate is 11% (36/331). Matched pairs of test characteristics were identified when the analysis was repeated using more than 10,000 colonies per mL as a positive culture. CONCLUSION: In this patient population, similar overtreatment and undertreatment rates were identified for various test cutoff points for urine dipstick tests and urinalysis. Although a urine dipstick may be equivalent to a urinalysis for the diagnosis of urinary tract infection, the limitations in the diagnostic accuracy of both tests should be incorporated into medical decisionmaking.

Comparison of ambulance dispatch protocols for nontraumatic abdominal pain.

STUDY OBJECTIVE: To compare rates of undertriage and overtriage of six ambulance dispatch protocols for the presenting complaint of nontraumatic abdominal pain, and to identify the optimal protocol. DESIGN: Retrospective prehospital and emergency department chart review to classify patients' conditions as "emergency" or "nonemergency." Utility analysis was used to identify the preferred protocol and monetary cost-effectiveness analysis to identify the least expensive protocol. SETTING: County emergency medical services (EMS) system with five receiving hospitals serving a mainly urban population of approximately 350,000. PARTICIPANTS: Records of 902 patients who called 911 for nontraumatic abdominal pain were reviewed; patients not transported were excluded. Twenty-seven county EMS medical directors completed questionnaires. RESULTS: Six ambulance dispatch protocols for nontraumatic abdominal pain were developed: indiscriminate-dispatch, four selective protocols, and no-dispatch. A dichotomous classification system was derived prospectively from the prehospital and medical records of patients who had activated the EMS system before the study period to define "emergency" and "nonemergency" conditions associated with nontraumatic abdominal pain. Emergency criteria identified patients with conditions requiring medical treatment within 1 hour. Reviewers determined, for each patient, whether an ambulance would have been dispatched by each of the protocols. Undertriage and overtriage rates were calculated for each protocol. County EMS medical directors assigned utility values to four potential outcomes of ambulance dispatch by the direct scaling method. The outcomes comprised correct and incorrect decisions to dispatch ambulances to patients with and without emergencies. The protocols were compared by decision analysis. A cost analysis was also performed, using an estimated marginal cost per transport of $302. Sensitivity analysis demonstrated the effect of varying the cost of an undertriage error and the cost per response. Of the 788 patients included in the study, 7.8% had conditions defined as emergencies. The four selective ambulance dispatch protocols had overtriage rates ranging from 10% to 51% and undertriage rates of 4% to 7%. None of the protocols was proven superior on the basis of the medical directors' assignment of utility values. The marginal cost of dispatching advanced life support ambulances to all patients with this complaint was $3,838 per emergency. CONCLUSION: The majority of patients with nontraumatic abdominal pain who requested ambulance transport during the study period did not have conditions that were classified as emergencies. In the study model, if an undertriage error costs more than $3,674, indiscriminate ambulance dispatch is the least expensive protocol, and if an undertriage error costs less than $3,674, no ambulance dispatch is the least expensive strategy.

Detection and management of foreign bodies in soft tissue.

The discovery and management of foreign bodies in soft tissue are challenging problems for emergency physicians. History, physical examination, and thorough wound exploration serve as the screening test for the presence of foreign bodies. Various radiographic studies can be performed to confirm the diagnosis, to identify the object's composition and shape, and to determine its approximate location in the tissues. Once the object is discovered, the clinician must weigh the potential harm of the foreign body in its current location against the risks of attempting removal.

Effect of povidone-iodine and saline soaking on bacterial counts in acute, traumatic, contaminated wounds.

It is common practice to soak acute traumatic wounds in dilute povidone-iodine solution before definitive wound cleaning and debridement. The effectiveness of soaking wounds is unknown. Using quantitative wound bacterial counts as a measure of efficacy, we compared wounds soaked in 1% povidone-iodine solution or in normal saline with wounds receiving no treatment. Adult patients were eligible for the study if they were seen in the emergency department with visibly contaminated traumatic wounds within 12 hours of injury. Patients were excluded if they refused consent, were allergic to iodine, or had taken antibiotics within five days; if the wound did not require debridement; if the wound had been previously cleaned; or if subsequent cultures were sterile. Thirty-three heavily contaminated acute traumatic wounds in 29 patients were included in the study. Wounds were randomly assigned to one of three groups. Tissue samples were taken before and after a ten-minute period of soaking in either povidone-iodine or saline; controls were covered with gauze during the ten-minute period. The mean bacterial count per gram of tissue decreased 6.4 x 10(5) (standard deviation, 1.68 x 10(6)) after no soak, increased 3.39 x 10(7) (1.05 x 10(8)) after saline soak, and decreased 9.19 x 10(6) (1.72 x 10(7)) after povidone-iodine soak. Wounds with counts of less than 10(5) bacteria/g tissue are unlikely to become infected. Multiple regression analysis was used to analyze the changes in bacterial count after treatment as a function of experimental group and initial bacterial count. There was no significant difference between the control and povidone-iodine groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Soft tissue foreign bodies.

Foreign bodies embedded in soft tissue can cause toxic and allergic reactions, inflammation, or infection, but the severity of these complications varies widely. Removal can be difficult and time consuming, and the potential damage to tissues caused by the procedure must be weighed against the risk posed by a particular foreign body. Plain and mammographic radiography, xeroradiography, computed tomography, and ultrasonography can be used to detect foreign bodies suspected during clinical evaluation. The exact position of an object buried in soft tissue is difficult to determine using two-dimensional imaging techniques. Surface markers, multiple-projection radiographs, wire grids, fluoroscopy, or stereotaxic devices may help to locate it. Not all foreign bodies are discovered during the initial patient encounter; several signs reveal the presence of a retained foreign body in a wound.

Use of antibiotics in the initial management of soft tissue hand wounds.

A prospective, randomized study was undertaken to determine the efficacy of prophylactic antibiotics in the treatment of various types of soft tissue hand wounds. A total of 394 patients were randomly assigned to one of two treatment groups, those receiving cephalexin (250 mg orally q.i.d. x 5 days), and the control group receiving no antibiotic. Patients were followed closely during the healing phase of their wounds. There was no statistical difference in the incidence of infection in the two groups.