Computed tomography-guided renal tumor biopsies: tumor imaging features affecting sample adequacy.

OBJECTIVE: The aim of this study was to derive a model that predicts when a computed tomography (CT)-guided renal tumor biopsy will be diagnostic based on the tumor's unenhanced imaging characteristics. METHODS: The CT images used to guide percutaneous biopsy and the pathology reports of 276 consecutive patients undergoing renal tumor biopsy were retrospectively reviewed. The effect of tumor size, growth pattern, location, and CT attenuation on the diagnostic biopsy rate was assessed using univariate and multivariate techniques. A model was derived using logistic regression, and its discrimination was evaluated using receiver operator characteristic curves. RESULTS: The diagnostic rate for all masses was 76.8% (212/276). Univariate and multivariate analyses revealed that increasing size and solid tumor attenuation were associated with diagnostic biopsies. The model demonstrates a discrimination of 0.71. CONCLUSIONS: The likelihood of a diagnostic biopsy of a solid tumor smaller than 1 cm and of any cystic tumor is significantly less than for larger solid renal tumors. The predictive model demonstrates moderate discrimination.

Computed tomographic angiography for the diagnosis of blunt carotid/vertebral artery injury: a note of caution.

OBJECTIVE: Computed tomographic angiography (CTA) by 16-channel multidetector scanner is increasingly replacing conventional digital subtraction angiography (DSA) for diagnosing or excluding blunt carotid/vertebral injuries (BCVI). To date there has been only 1 study in which all patients received both examinations. That study reported a high accuracy for 16-detector CTA. The current prospective parallel comparative study aims at validating this high accuracy and examining the rates of evaluability of CTA performed with a 16-detector scanner with image reconstruction by modern imaging software. METHODS: Patients at risk for BCVI (facial/cervical-spinal fractures; unexplained neurologic deficit; anisocoria; lateral neck soft tissue injury; clinical suspicion) underwent both CTA (16-channel multidetector scanner) and DSA. Results of the 2 studies and the clinical course were prospectively recorded. RESULTS: During the 40-month study period ending March 2007, approximately 7000 blunt trauma patients were evaluated and of these 119 (1.7%) consecutive patients meeting inclusion criteria were screened by CTA. Ninety-two patients underwent confirmatory DSA. Twenty-three (22%) DSA identified 26 BCVI (vertebral, 13; carotid, 13). Among these 23 CTAs, 17 identified 19 BCVIs (vertebral, 10; carotid, 9) (true positives), and 6 failed to identify 7 BCVIs (vertebral, 3; carotid, 4) (false negatives). Sixty-nine of the 92 DSA were normal. Of these 69 CTAs, 10 were falsely suspicious for 11 BCVIs (vertebral, 7; carotid, 4) (false positives), and 56 were normal (true negatives). The remaining 3 CTAs were nonevaluable (mistimed contrast, 1; streak artifact, 2). Sixteen of 89 (18%) evaluable CTAs, were suboptimal (mistimed contrast, 9; streak artifacts, 4; motion artifact, 2; body habitus, 1). Excluding the 3 nonevaluable CTAs, the sensitivity, specificity, positive and negative predictive values of CTA for diagnosing or excluding BCVI were 74%, 86%, 65%, and 90% respectively. One patient with grade II carotid artery injuries (by CTA and DSA) on antiplatelet agent developed stroke related to carotid artery injuries. CONCLUSIONS: Current CTA technology cannot reliably diagnose or exclude BCVI. Twenty percent of CTAs are either nonevaluable or suboptimal. Until more data are available and the technique is standardized, the current trend towards using CTA to screen for and/or diagnose these rare but potentially devastating injuries is dangerous.

Placement of intracranial pressure monitors: are "normal" coagulation parameters necessary?

INTRODUCTION: Patients with head injuries frequently have abnormal coagulation studies. Monitoring intracranial pressure (ICP) in head injured patients is common practice, but no best practice guidelines exist for coagulation parameters for ICP monitor placement. PURPOSE: To test the hypothesis that hemorrhagic complication rates from ICP monitor placement are low and that the use of FFP to correct coagulation parameters to "normal" is not indicated. METHODS: Retrospective review of all patients admitted to a Level I trauma center over a 3 year period, who underwent fiberoptic intraparenchymal ICP monitoring was undertaken. Inclusion criteria were coagulation studies (prothrombin time (PT), partial thromboplastin time (PTT), international normalized ratio (INR), platelet count) before ICP monitor placement and head CT scans to assess for hemorrhage before and after monitor placement. Data collected included age, Glasgow coma score (GCS), head region abbreviated injury score (H_AIS), time to ICP monitor placement, complications and outcomes. RESULTS: From 8/1/00 through 7/31/03, 5163 trauma patients were admitted, and 157 met inclusion criteria. Patients were stratified by INR, at the time of ICP placement as normal (0.8-1.2, 103 patients), borderline (1.3-1.6, 42 patients) and increased (>/=1.7, 12 patients). There was no difference between the groups in age, gender or H_AIS. Twenty two patients had component therapy to correct coagulopathy before ICP insertion, but 10 had INRs in the borderline group and 12 remained with INRs >/=1.7. Eleven patients had platelet counts 50,000-100,000 at ICP monitor placement, despite platelet transfusions. Time from admission to ICP monitor placement was significantly longer in patients who received component therapy (19.2 +/- 19.7 hours versus 8.8 +/- 13.9 hours, p < 0.002). Three patients had clinically insignificant, petechial hemorrhages (1.9%); one in each group, with INRs of 1.2, 1.3, and 2.5, respectively. CONCLUSIONS: In patients with INR

Are automated blood pressure measurements accurate in trauma patients?

BACKGROUND: Automated blood pressure (BP) determinations by oscillometry are reported to be as accurate as invasive monitoring for systolic pressures as low as 80 mm Hg. Automated BP devices are widely used by prehospital providers and in hospital operating rooms, emergency departments, and intensive care units, although the accuracy of automated BP has not been demonstrated in trauma patients. We hypothesized that automated BP is less accurate than manual BP in trauma patients. The purpose of this study was to determine the accuracy of automated BP versus manual BP in trauma patients. METHODS: A retrospective review of patients who met trauma activation criteria admitted to a Level I trauma center over a 30-month period was conducted. Patients were included if both manual BP and automated BP were measured within 5 minutes of admission. Additional data collected included Injury Severity Score, base deficit, and emergency department resuscitation volume. Statistical analysis was performed using paired t test, chi2, and linear regression analysis. Significance was attributed to a value of p < 0.05. RESULTS: From January 2000 through June 2002, 388 patients met inclusion criteria. Patients were grouped by manual BP levels: group 1, BP < or = 90 mm Hg (n = 92); group 2, BP 91-110 mm Hg (n = 119); and group 3, BP > or = 110 mm Hg (n = 177). The mean automated BP measurements were significantly higher than the manual measurements in groups 1 and 2 (26 and 16 mm Hg, respectively; p < 0.001). Of the 92 patients with manual BP < or = 90, 45 (49%) had automated BP > or = 100. The base deficit (-5, -3, and -2 for groups 1, 2, and 3, respectively; p < 0.01), Injury Severity Score (30, 25, and 18; p < 0.01), and volume of resuscitative fluid and blood (p < 0.001) all decreased with higher BP group. CONCLUSION: Injury severity, degree of acidosis, and resuscitation volume were more accurately reflected by manual BP. Automated BP determinations were consistently higher than manual BP, particularly in hypotensive patients. Automated BP devices should not be used for field or hospital triage decisions. Manual BP determinations should be used until systolic blood pressure is consistently > or = 110 mm Hg.