Robert Knopp

Accuracy of Standard Radiographic Views in Detecting Cervical Spine Fractures

Recent studies have challenged the accuracy of standard radiographs for detecting cervical spine injuries. We used thin-section tomography to determine the accuracy of the cross-table lateral view (CTLV) alone, and the three standard emergency department views (CTLV, anteroposterior, and open-mouth) together, for detecting acute cervical spine fractures. Seventy-one patients with blunt cervical spine injuries had thin-section tomography performed for the following indications: fracture, dislocation, or suspicious findings on standard radiographs; or persistent severe pain or neurologic deficit. Tomography detected acute fractures in 44 of the 71 patients. The CTLV had a sensitivity of 82%, specificity of 70%, and accuracy of 77% for detecting patients with fractures. The three standard views had a corresponding sensitivity, specificity, and accuracy of 93%, 71%, and 84%, respectively. Eight patients with fractures had the CTLV interpreted as normal, and three patients with fractures had all three standard views interpreted as normal. The use of thin-section tomography is recommended when there are suspicious radiographic or clinical findings suggesting a severe cervical spine injury.

Comparison of Five-View and Three-View Cervical Spine Series in the Evaluation of Patients With Cervical Trauma

The three-view trauma series has been the standard screening examination for patients with cervical spine trauma. We conducted a prospective study to determine if the addition of supine oblique views to the three-view series would improve detection of fractures, subluxations, dislocations, or locked facets. All patients over a two-year period with suspected cervical spine injury had a five-view series obtained (three-view series and supine oblique views), and selected high-risk patients underwent thin-section conventional tomography of the cervical spine. Films were interpreted separately by two radiologists and an emergency physician, and the tomography results were used as the gold standard for comparison. Thirty-three of 58 high-risk patients had one or more fractures, subluxation, or dislocation demonstrated on tomography. There were no fractures or dislocations detected on the five-view series that were not detected or suspected on the three-view series. In areas of the cervical spine reported to be better visualized by supine oblique views than three-view series, our results indicate that supine oblique views did not improve detection but did, in certain cases, allow more specific diagnosis of injuries. Our data do not support the routine use of supine oblique views in the initial radiographic evaluation of patients with cervical spine trauma.

Mechanism of injury and anatomic injury as criteria for prehospital trauma triage

Prehospital trauma triage should permit accurate identification and transport of patients with critical injuries to trauma centers without overloading these centers with patients having minor injuries. In most trauma systems a combination of physiologic criteria (Trauma Score [TS]), mechanisms of injury (MOI), and anatomic injury (AI) are used as prehospital trauma triage criteria. The purpose of our study was to assess the predictive value of specific MOI and AI in detecting critically injured trauma victims (Injury Severity Score [ISS] of more than 15) and determine the best combination of TS, MOI, and AI that produced the lowest percentage of undertriage and overtriage. Previous studies have examined only patients triaged to trauma centers; our study included all trauma patients regardless of destination. A total of 1,473 trauma patients was evaluated and transported by the emergency medical services system and studied prospectively during a nine-week period. Prehospital TS, specific MOI and AI, and final disposition and diagnosis were determined on all patients. The ISS was calculated on all hospital admissions. A total of 97 patients had an ISS of more than 15. Three hundred forty-one (23%) had one of the specific MOI studied; 102 (6.9%) had one of the specific AI studied. Four hundred twelve patients (28%) had at least one of the study MOI or AI.(ABSTRACT TRUNCATED AT 250 WORDS)

Endotracheal intubation of pediatric patients by paramedics

Although a number of studies have described endotracheal intubation of adult patients in the prehospital setting, there are few studies on prehospital endotracheal intubation of pediatric patients. The purposes of our study were to determine how frequently prehospital endotracheal intubation was used in pediatric cardiopulmonary arrests when a paramedic trained in endotracheal intubation was present, to determine the success rate and complications associated with the procedure in the field, and to compare resuscitation rates and outcome in patients with and without prehospital endotracheal intubation. Our retrospective study covered a 38-month period and included all prehospital victims of medical cardiopulmonary arrest under the age of 19 years. Data were collected from field assessment forms and validated by hospital charts, autopsy reports, coroners reports, death certificates, and emergency medical services central dispatch logs. Of 63 victims of medical cardiorespiratory arrest, 42 had intubating paramedics present at the scene. Twenty-eight of 42 patients (66%) had endotracheal intubation attempted. Eighteen of 28 attempts (64%) were successful, associated with a major complication rate of 7% (two of 28) and a minor complication rate of 39% (11 of 28). In patients less than 1 year old, only six of 16 (38%) had endotracheal intubation attempted and only three of six (50%) attempts were successful. Of the 18 patients who were intubated successfully before arrival at the hospital, nine (50%) survived to hospital admission and one (6%) survived to discharge. The remainder died in the emergency department.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood volume distribution in the Trendelenburg position

The Trendelenburg position is used frequently in treating hypotensive patients. It is believed that placing patients in the Trendelenburg position causes an autotransfusion of blood to the central circulation. No published studies document the volume of blood displaced centrally. In our study ten volunteers were placed in the Trendelenburg position. Blood volumes were determined from body surface area, and radionuclide scanning was used to determine blood volume distribution. Placing normovolemic volunteers in the Trendelenburg resulted in a 1.8% (median) displacement of the total volume centrally. The autotransfusion of blood produced by the Trendelenburg position is small and is unlikely to have an important clinical effect.

Blood Volume Displacement with Inflation of Antishock Trousers

Eleven healthy male volunteers were studied to determine the amount of blood displaced by the inflation of the antishock trousers (AST) at pressures of 40 and 100 mm Hg. Radioisotope scans were used to determine the blood volume distribution and the change in the volume of distribution with inflation of the AST. The volunteers were then phlebotomized approximately one liter of blood and the study was repeated. Less than 5% of the total blood volume was displaced with inflation of the AST. It is unlikely that the clinical improvement seen with inflation of the AST in hypovolemic shock is due to autotransfusion of blood alone.

Use of the tilt test in measuring acute blood loss

We undertook to determine the accuracy of the tilt test in detecting acute blood loss. One hundred volunteers were phlebotomized a specific amount of blood (Group I, 450 cc; Group II, 1,000 cc in 500 cc increments). Orthostatic vital signs were recorded at timed intervals comparing the supine to sitting and supine to standing techniques. Using the criteria of pulse increase greater than or equal to 30/min or severe symptoms, the supine to standing test accurately distinguished 1,000 cc blood loss from no blood loss in our population. The major value of the tilt test is detecting blood loss of 1,000 cc or more.

Recommendations for Evaluation of the Acutely Injured Cervical Spine: A Clinical Radiologic Algorithm

A clinical radiologic algorithm is presented for the evaluation of the acutely injured cervical spine. Available radiologic techniques are described. An attempt is made to match the clinical indicators of injury to the appropriate level of radiologic investigation, thus maximizing the efficacy of the work-up.

Prehospital patients refusing care

In summary, many of the complex medicolegal and ethical issues surrounding the prehospital patient who refuses all or part of the care offered by the EMS system have been reviewed. The best outcome can be achieved using a sliding scale of capacity and a conservative approach to treatment rather than releasing the patient at the scene. Finally, the roles of collateral history, inquiries as to the origin of the patients refusal of care, direct physician interaction with the patient, a spirit of creativity and compromise in dealing with the patient, meticulous documentation, and policy issues have been discussed.

Urine sampling in ambulatory women: Midstream clean-catch versus catheterization

We conducted a study to determine if there were any significant differences in urinalyses or urine cultures obtained by midstream clean-catch (MSCC) urine sampling in comparison with in-and-out catheterization (CATH). One hundred five women with symptoms suggestive of a urinary tract infection were studied prospectively. Each woman had a MSCC urine sample obtained initially, followed by a CATH sample. The MSCC and CATH urine samples were analyzed and compared for urine culture, leukocyte esterase, nitrites, microscopic bacteriuria, and pyuria. Of the 105 patients, 42 (40%) had a culture-proven urinary tract infection. The concordance rates between MSCC and CATH urine cultures, nitrites, leukocyte esterase, significant microscopic bacteriuria, and pyuria were 96%, 94%, 93%, 90%, and 90%, respectively. There were no statistically significant differences between MSCC and CATH sensitivities, specificities, or positive or negative predictive values for any urinalysis variable (leukocyte esterase, nitrites, significant microscopic bacteriuria, or pyuria). We conclude that if proper MSCC technique is used, the differences between MSCC and CATH urinalyses or urine cultures do not appear to be significant in the majority of ambulatory women without active vaginal bleeding who present with symptoms suggestive of a urinary tract infection.