Quantitative Neuromuscular Monitoring in Clinical Practice: A Professional Practice Change Initiative.

BACKGROUND: Residual neuromuscular blockade can be avoided with quantitative neuromuscular monitoring. The authors embarked on a professional practice initiative to attain documented train-of-four ratios greater than or equal to 0.90 in all patients for improved patient outcomes through reducing residual paralysis. METHODS: The authors utilized equipment trials, educational videos, quantitative monitors in all anesthetizing locations, and electronic clinical decision support with real-time alerts, and initiated an ongoing professional practice metric. This was a retrospective assessment (2016 to 2020) of train-of-four ratios greater than or equal to 0.9 that were documented before extubation. Anesthesia records were manually reviewed for neuromuscular blockade management details. Medical charts of surgical patients who received a neuromuscular blocking drug were electronically searched for patient characteristics and outcomes. RESULTS: From pre- to postimplementation, more patients were assigned American Society of Anesthesiologists Physical Status III to V, fewer were inpatients, the rocuronium average dose was higher, and more patients had a prereversal train-of-four count less than 4. Manually reviewed anesthesia records (n = 2,807) had 2 of 172 (1%) cases with documentation of train-of-four ratios greater than or equal to 0.90 in November 2016, which was fewer than the cases in December 2020 (250 of 269 [93%]). Postimplementation (February 1, 2020, to December 31, 2020), sugammadex (650 of 935 [70%]), neostigmine (195 of 935 [21%]), and no reversal (90 of 935 [10%]) were used to attain train-of-four ratios greater than or equal to 0.90 in 856 of 935 (92%) of patients. In the electronically searched medical charts (n = 20,181), postimplementation inpatients had shorter postanesthesia care unit lengths of stay (7% difference; median [in min] [25th, 75th interquartile range], 73 [55, 102] to 68 [49, 95]; P < 0.001), pulmonary complications were less (43% difference; 94 of 4,138 [2.3%] to 23 of 1,817 [1.3%]; P = 0.010; -1.0% difference [95% CI, -1.7 to -0.3%]), and hospital length of stay was shorter (median [in days] [25th, 75th], 3 [2, 5] to 2 [1, 4]; P < 0.001). CONCLUSIONS: In this professional practice initiative, documentation of train-of-four ratios greater than or equal to 0.90 occurred for 93% of patients in a busy clinical practice. Return-of-strength documentation is an intermediate outcome, and only one of many factors contributing to patient outcomes.

Association of Use of Contract Nurses With Hospitalized Patient Pressure Injuries and Falls.

BACKGROUND: Hospital-acquired pressure injuries (HAPIs) and falls are outcomes sensitive to quality of nursing care. Use of contract (traveler) nurses varies among organizations, but there is little research on the effect of contract nurses on nurse-sensitive outcomes. OBJECTIVES: To explore the relationship between use of contract nurses and two key nurse-sensitive outcomes, HAPIs and falls. RESEARCH DESIGN: This was a cross-sectional study of unit-level nursing, patient, and hospital factors versus HAPIs and falls from a national nursing data consortium from 2015 to 2016. We used cluster analysis to identify similar units, and compared outcomes between clusters. SUBJECTS: 605 nursing units in 166 hospitals, 3.2 patients per nurse, and 5.3% contract nurses. MEASURES: Prevalence and incidence of HAPIs and number of falls, adjusted by patient days. RESULTS: For both prevalence and incidence of HAPIs, there was a statistically significant difference between the five independent cluster groups (p = .012 and p = .001, respectively). The cluster with the highest percentage of nurse travelers (>7%) had the highest HAPI prevalence (0.84%) and incidence (0.055 per 1,000 patient days) despite higher nurse staffing, compared to HAPI prevalence of 0.32% and incidence of 0.017 per 1,000 patient days in the cluster with the lowest percentage of nurse travelers (<2%). We did not identify a consistent relationship between use of contract nurses and falls. CONCLUSIONS: Use of contract nurses was associated with higher HAPI prevalence and incidence, independent of staffing levels. CLINICAL RELEVANCE: Our results suggest that institutions should either minimize the use of contract nurses, or engage in extensive training to confirm that contract nurses have understanding of the institutional practices around HAPIs.

Clinical Decision Support: Opportunity or Armageddon?

OBJECTIVE. The objective of this article is to discuss clinical decision support (CDS) and the article by Palen and colleagues in this issue of AJR. CONCLUSION. The Palen et al. study provides strong evidence to date that CDS can lead to improvement in imaging appropriateness scores. However, the relevance of appropriateness scores in clinical practice is unknown and CDS is potentially highly disruptive to workflow, and therefore research into its true impact on clinical care is essential.

Changes in Provider Prescribing Patterns After Implementation of an Emergency Department Prescription Opioid Policy.

BACKGROUND: Prescription opioid-associated abuse and overdose is a significant cause of morbidity and mortality in the United States. Opioid prescriptions generated from emergency departments (EDs) nationwide have increased dramatically over the past 20 years, and opioid-related overdose deaths have become an epidemic, according to the Centers for Disease Control and Prevention. OBJECTIVE: Our aim was to determine the effectiveness of implementing a prescription policy for opioids on overall opioid prescribing patterns in a hospital ED. METHODS: The ED provider group of an academic, non-university-affiliated urban hospital with 23,000 annual patient visits agreed to opioid prescribing guidelines for chronic pain with the goal of limiting prescriptions that may be used for abuse or diversion. These guidelines were instituted in the ED through collaborative staff meetings and educational and training sessions. We used the electronic medical record to analyze the number and type of opioid discharge prescriptions during the study period from 2006-2014, before and after the prescribing guidelines were instituted in the ED. RESULTS: The number of patients discharged with a prescription for opioids decreased 39.6% (25.7% to 15.6%; absolute decrease 10.2%; 95% confidence interval [CI] 9.6-10.7; p < 0.001) after the intervention. The improvements were sustained 2.5 years after the intervention. Decreases were seen in all major opioids (hydrocodone, oxycodone, hydromorphone, and codeine). The number of pills per prescription also decreased 14.8%, from 19.5% to 16.6% (absolute decrease 2.9; 95% CI 2.6-3.1; p < 0.001). CONCLUSIONS: Implementation of an ED prescription opioid policy was associated with a significant reduction in total opioid prescriptions and in the number of pills per prescription.

Engaging Frontline Leaders and Staff in Real-Time Improvement.

BACKGROUND: The relationship of staff satisfaction and engagement to organizational success, along with the integral influence of frontline managers on this dimension, is well established in health care and other industries. To specifically address staff engagement, Virginia Mason Medical Center, an integrated, single-hospital health system, developed an approach that involved leaders, through the daily use of standard work for leaders, as well as staff, through a Lean-inspired staff idea system. METHODS: Kaizen Promotion Office (KPO) staff members established three guiding principles: (1) Staff engagement begins with leader engagement; (2) Integrate daily improve- ment (kaizen) as a habitual way of life not as an add-on; and (3) Create an environment in which staff feel psycho- logically safe and valued. Two design elements--Standard Work for Leaders (SWL) and Everyday Lean Ideas (ELIs) were implemented. RESULTS: For the emergency department (ED), an early adopter of the staff engagement work, the challenge was to apply the guiding principles to improve staff engagement while improving quality and patient and staff satisfaction, even as patient volumes were increasing. Daily huddles for the KPO staff members and weekly leader rounds are used to elicit staff ideas and foster ELIs in real time. Overall progress to date has been tracked in terms of staff satisfaction surveys, voluntary staff turnover, adoption of SWL, and testing and implementation of staff ideas. For example, voluntary turnover of ED staff decreased from 14.6% in 2011 to 7.5% in 2012, and 2.0% in 2013. Organizationwide, at least 800 staff ideas are in motion at any given time, with finished ones posted in an idea supermarket website. CONCLUSION: A leadership and staff engagement approach that focuses on SWL and on capturing staff ideas for daily problem solving and improvement can contribute to organization success and improve the quality of health care delivery.

The quality movement or making radiology fun again.

Quality can be seen as the link between what we do as radiologists and patient health. The radiology quality movement represents an opportunity for radiologists to have more direct influence on patient health, including the quality domains of safety, effectiveness, patient centeredness, timeliness, efficiency, and equitability. Focusing on quality allows emergency radiologists to extend outside of the confines of the reading room, thereby enhancing a rewarding and clinically relevant practice.

Using lean "automation with a human touch" to improve medication safety: a step closer to the "perfect dose".

BACKGROUND: Virginia Mason Medical Center (Seattle) employed the Lean concept of Jidoka (automation with a human touch) to plan for and deploy bar code medication administration (BCMA) to hospitalized patients. METHODS: Integrating BCMA technology into the nursing work flow with minimal disruption was accomplished using three steps ofJidoka: (1) assigning work to humans and machines on the basis of their differing abilities, (2) adapting machines to the human work flow, and (3) monitoring the human-machine interaction. Effectiveness of BCMA to both reinforce safe administration practices and reduce medication errors was measured using the Collaborative Alliance for Nursing Outcomes (CALNOC) Medication Administration Accuracy Quality Study methodology. Trained nurses observed a total of 16,149 medication doses for 3,617 patients in a three-year period. RESULTS: Following BCMA implementation, the number of safe practice violations decreased from 54.8 violations/100 doses (January 2010-September 2011) to 29.0 violations/100 doses (October 2011-December 2012), resulting in an absolute risk reduction of 25.8 violations/100 doses (95% confidence interval [CI]: 23.7, 27.9, p < .001). The number of medication errors decreased from 5.9 errors/100 doses at baseline to 3.0 errors/100 doses after BCMA implementation (absolute risk reduction: 2.9 errors/100 doses [95% CI: 2.2, 3.6,p < .001]). The number of unsafe administration practices (estimate, -5.481; standard error 1.133; p < .001; 95% CI: -7.702, -3.260) also decreased. CONCLUSION: As more hospitals respond to health information technology meaningful use incentives, thoughtful, methodical, and well-managed approaches to technology deployment are crucial. This work illustrates how Jidoka offers opportunities for a smooth transition to new technology.

Applying lean methods to improve quality and safety in surgical sterile instrument processing.

BACKGROUND: Surgical instrument processing is critical to safe, high-quality surgical care but has received little attention in the medical literature. Typical hospitals have inventories in the tens of thousands of surgical instruments organized into thousands of instrument sets. The use of these instruments for multiple procedures per day leads to millions of instrument sets being reprocessed yearly in a single hospital. Errors in the processing of sterile instruments may lead to increased operative times and costs, as well as potentially contributing to surgical infections and perioperative morbidity. METHODS: At Virginia Mason Medical Center (Seattle), a quality monitoring approach was developed to identify and categorize errors in sterile instrument processing, through use of a daily defect sheet. Lean methods were used to improve the quality of surgical instrument processing through redefining operator roles, alteration of the workspace, mistake-proofing, quality monitoring, staff training, and continuous feedback. To study the effectiveness of the quality improvement project, a before/after comparison of prospectively collected sterile processing error rates during a 37-month time frame was performed. RESULTS: Before the intervention, instrument processing errors occurred in 3.0% of surgical cases, decreasing to 1.5% at the final follow-up (p < .001). Improvements were observed in multiple categories of error types, particularly the assembly errors of packaging (from 0.66 to 0.24 errors per hundred cases, p = .004), and foreign objects (0.17 to 0.02 errors per hundred cases, p = .025). CONCLUSION: Surgical instrument processing errors are a barrier to the highest quality and safety in surgical care but are amenable to substantial improvement using Lean techniques.

Using lean to improve medication administration safety: in search of the "perfect dose".

BACKGROUND: At Virginia Mason Medical Center (Seattle), the Collaborative Alliance for Nursing Outcomes (CALNOC) Medication Administration Accuracy Quality Study was used in combination with Lean quality improvement efforts to address medication administration safety. METHODS: Lean interventions were targeted at improving the medication room layout, applying visual controls, and implementing nursing standard work. The interventions were designed to prevent medication administration errors through improving six safe practices: (1) comparing medication with medication administration record, (2) labeling medication, (3) checking two forms of patient identification, (4) explaining medication to patient, (5) charting medication immediately, and (6) protecting the process from distractions/interruptions. RESULTS: Trained nurse auditors observed 9,244 doses for 2,139 patients. Following the intervention, the number of safe-practice violations decreased from 83 violations/100 doses at baseline (January 2010-March 2010) to 42 violations/100 doses at final follow-up (July 2011-September 2011), resulting in an absolute risk reduction of 42 violations/100 doses (95% confidence interval [CI]: 35-48), p < .001). The number of medication administration errors decreased from 10.3 errors/100 doses at baseline to 2.8 errors/100 doses at final follow-up (absolute risk reduction: 7 violations/100 doses [95% CI: 5-10, p < .001]). The "perfect dose" score, reflecting compliance with all six safe practices and absence of any of the eight medication administration errors, improved from 37 in compliance/100 doses at baseline to 68 in compliance/100 doses at the final follow-up. CONCLUSION: Lean process improvements coupled with direct observation can contribute to substantial decreases in errors in nursing medication administration.

Feasibility and safety of a rapid-access transient ischemic attack clinic.

BACKGROUND: In the United States, patients with transient ischemic attacks (TIAs) are commonly admitted to the hospital despite evidence that low-risk TIA patients achieve improved outcomes at lower costs at specialized rapid-access TIA clinics (RATCs). LOCAL PROBLEM: All patients experiencing TIAs at a hospital system in the Pacific Northwest were being admitted to the hospital. This project aimed to implement an RATC to relocate care for low-risk TIA patients, showing feasibility and safety. METHODS: Following implementation of the RATC, a retrospective chart review was performed. Outcomes included days to RATC; days to magnetic resonance imaging (MRI); final diagnosis; stroke-related admissions and deaths within 90 days of the RATC visit. INTERVENTIONS: From 2016 to 2018, implementation of an RATC included patient triage tools; multidisciplinary collaboration between departments; a direct scheduling pathway; and emphasis on stroke prevention. RESULTS: Ninety-nine patients were evaluated in the RATC, 69% (69/99) were referred from the emergency department. Sixty-six percent of patients were seen in the TIA clinic in 2 days or less, 19% at 3 days, and 15% at 4 days or more. Mean days to TIA clinic was 2.5 days (SD 2.4). Mean days (SD) to MRI was 2.1 days (SD 2.3). Forty-eight percent (48/99) had a final diagnosis of probable TIA, followed by 32% (32/99) who had other diagnoses; 15% (15/99) migraine variant; 4% (4/99) with stroke. Two percent (2/99) of patients had a stroke-related admission within 90 days, another 2% (2/99) died of non-stroke-related causes within 90 days of the RATC visit. CONCLUSIONS: Utilization of RATCs is feasible and safe. Nurse practitioners are integral in delivering this innovative, cost-effective model of care.

Coupling Lean and Experience-Based Design for Measuring and Incorporating Patient Emotional Experience Into the Redesign of Health Care.

BACKGROUND AND OBJECTIVES: Incorporation of Lean into health care requires consideration of the patient and other customer experience of care as well as final health outcomes. We incorporate experience-based design (EBD) into our Lean management method to assess the experience of care, guide redesign of care processes, and assess the effectiveness of quality improvement on the care experience. Foundational to EBD is identification of "touch points," moments in the health care delivery process where a patient has a strong positive or negative emotional response that has the potential to alter the way patients feel about their overall care experience. METHODS: EBD proceeds sequentially from qualitative assessment of customer experience and touch points (through observations and interviews); semiquantitatively assessing the experience across many patients (through EBD questionnaires); engaging in codesign with patients (through improvement teams and events); and reassessing the care experience after improvement (through follow-up EBD questionnaires). The use of project-specific (EBD) emotion word questionnaires enables assessment of change over time. These EBD questionnaires are developed ad hoc for each care improvement effort, to reflect the specific high emotion touch points patients identify for that care process, and therefore pose unique validity and reliability challenges. We have previously validated a set of emotion words that form the library from which questionnaire designers select the relevant emotion word choices. In addition, to assess consistency of measurement in the absence of any improvement, we performed a repeated-measures study deploying the same EBD questionnaire to different groups of patients, separated by a 60-day interval in the absence of any quality improvement work. RESULTS: We apply EBD across the health care enterprise, including patients and family caregivers, as well as staff members. Examples where EBD has been incorporated into care redesign have included; outpatient care for pancreatic cancer patients; clinic visits in rheumatology; delirium care for hospital inpatients; and the orientation process for newly hired advanced practice providers. Our reliability data demonstrate that moderate differences in scores on the EBD questionnaire (up to 19 percentage points) may reflect random variability, but differences of greater magnitude reflect actual changes in the patient experience. CONCLUSIONS: In summary, experience-based design has promise as a methodology to incorporate patient experience within a Lean management structure. EBD can aid with health care redesign, defining the emotional touch points that are foundational to the experience of care, enabling targeting of quality improvement efforts, and assessing change.

Probability of malignancy for lesions detected on breast MRI: a predictive model incorporating BI-RADS imaging features and patient characteristics.

OBJECTIVES: To predict the probability of malignancy for MRI-detected breast lesions with a multivariate model incorporating patient and lesion characteristics. METHODS: Retrospective review of 2565 breast MR examinations from 1/03-11/06. BI-RADS 3, 4 and 5 lesions initially detected on MRI for new cancer or high-risk screening were included and outcomes determined by imaging, biopsy or tumor registry linkage. Variables were indication for MRI, age, lesion size, BI-RADS lesion type and kinetics. Associations with malignancy were assessed using generalized estimating equations and lesion probabilities of malignancy were calculated. RESULTS: 855 lesions (155 malignant, 700 benign) were included. Strongest associations with malignancy were for kinetics (washout versus persistent; OR 4.2, 95% CI 2.5-7.1) and clinical indication (new cancer versus high-risk screening; OR 3.0, 95% CI 1.7-5.1). Also significant were age > = 50 years, size > = 10 mm and lesion-type mass. The most predictive model (AUC 0.70) incorporated indication, size and kinetics. The highest probability of malignancy (41.1%) was for lesions on MRI for new cancer, > = 10 mm with washout. The lowest (1.2%) was for lesions on high-risk screening, <10 mm with persistent kinetics. CONCLUSIONS: A multivariate model shows promise as a decision support tool in predicting malignancy for MRI-detected breast lesions.

Opportunistic Screening of Patients for Hepatic Steatosis: Clinical Follow-Up and Diagnostic Yield.

PURPOSE: Hepatic steatosis is a common incidental finding on abdominal imaging that is not always reported or recognized as having clinical significance. Because of its association with liver disease, cirrhosis, and diabetes, the aim of this study was to bring attention to this finding and provide clinical guidance to referring clinicians by inserting standardized text into radiology reports of patients with incidentally detected hepatic steatosis. METHODS: Patients with incidentally discovered hepatic steatosis on abdominal ultrasound or CT had standard text inserted into the impression sections of their diagnostic imaging reports. A total of 1,256 patients whose reports were tagged between April 2016 and September 2017 were retrospectively identified and their electronic medical records reviewed to determine subsequent acknowledgment in the medical record or clinical action in response to the tagged report. Information regarding patient demographics, the type of provider who ordered the examination, and the acuity of the examination results was also recorded. RESULTS: Acknowledgment and subsequent clinical action were more likely in patients whose examinations was ordered by primary care providers, whose examination results were not urgent, and who were in the ultrasound group. The overall diagnostic yield in patients who underwent clinical evaluation was nonalcoholic fatty liver disease in 70%, nonalcoholic steatohepatitis in 6%, and alcoholic hepatitis in 17%. CONCLUSIONS: Opportunistic screening for incidental hepatic steatosis on abdominal CT and ultrasound is feasible, with substantial yield for patients with clinically important entities including nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.

Using Lean tools to improve the efficiency of awake fibreoptic intubation setup.

BACKGROUND: Awake fibreoptic intubation is a complex advanced airway technique used by anaesthesiologists in the management of a difficult airway. The time to setup this important procedure can be significant which may dissuade its use by some providers. In our institution, the awake intubation setup process was highly variable and error prone. METHODS: We deployed Lean methods to improve the efficiency and accuracy of the awake fibreoptic intubation setup process. A 2-day improvement event with a multidisciplinary team addressed the setup process, tested solutions and created standard work documents. Twenty awake fibreoptic intubation simulations were conducted before and after the intervention to quantify gains in setup efficiency and error reduction. RESULTS: Variability in the setup process, including clinical locations visited, was reduced through creating a standardised process. The average time to for an awake fibreoptic intubation setup was reduced by approximately 50%, from 23 min to 11 min (p<0.001). In addition, awake fibreoptic intubation equipment set out without error increased in the postintervention simulations from 59% to 85% (p=0.003). CONCLUSION: Using Lean tools, we were able to make the setup of awake fibreoptic intubation not only more efficient, but also more accurate. A similar methodological approach may have value for other complex anaesthesia procedures.

MRI and muscle enzymes do not support the diagnosis of local anesthetic myotoxicity: a descriptive case series.

BACKGROUND: The presence of thigh muscle edema as characterized by increased signal intensity on MRI has been used to support the diagnosis of presumed local anesthetic-induced myotoxicity reported after total knee arthroplasty (TKA) with continuous adductor canal block (CACB). However, neither postoperative baseline imaging appearance nor muscle enzyme values have been described in conjunction with this clinical scenario. Thus, the usefulness of MRI or enzymatic biomarkers of muscle injury for supporting the diagnosis of local anesthetic myotoxicity is unknown. METHODS: This descriptive case series documents postoperative MRI appearance of the ipsilateral upper leg, plus preoperative and postoperative creatine phosphokinase and aldolase values in volunteer patients who underwent uncomplicated TKA with CACB. RESULTS: In 27 volunteer patients with no postsurgical evidence of clinically relevant myotoxicity, anterior thigh muscle edema was universally evident on imaging (n=12) and muscle enzyme values (n=19) were normal or only slightly elevated. CONCLUSIONS: The non-specificity of these findings suggests that MRI and near normal muscle enzyme levels are of limited diagnostic value when there is clinical suspicion of local anesthetic myotoxicity in the setting of TKA with CACB. TRIAL REGISTRATION NUMBER: NCT04821245.

The Relationship Between Medicare Outpatient Efficiency Measure OP8 and Lumbar MRI Utilization.

INTRODUCTION: Quality-based reporting and payment are predicated on using valid metrics. We sought to determine the relationship between widely used lumbar imaging quality metric OP8 and underlying quality as measured through actual utilization of lumbar MRI. METHODS: We performed a multi-institutional cross-sectional study using hospital-level billing data from a major commercial insurance company, including 23 Washington State hospitals from July 1, 2014, to June 30, 2015, with more than 25 eligible visits. For each hospital, we determined the OP8 score using the CMS published specifications. We calculated actual utilization rate from the proportion of patients visiting primary care (internal medicine or family medicine, including physicians, nurse practitioners, and physician assistants) for uncomplicated low back pain who underwent lumbar MRI. For both measures, patients under age 18 or with complicated conditions (eg, infection, cancer, inflammatory arthropathy) were excluded. OP8 scores and utilization were compared using linear regression and correlation coefficients. RESULTS: Hospital scores ranged from 28.0% to 55.3% on OP8 and from 0.7% to 4.2% on MRI utilization (with lower scores indicating better performance). There was no association between score on OP8 and actual utilization of lumbar MRI across hospitals in Washington State (attributable risk 0.00016, 95% confidence interval: -0.00026, 0.00059, P = .43). DISCUSSION: Widely used imaging efficiency measure OP8 does not correlate with actual utilization of lumbar MRI. Better OP8 scores reflect use of antecedent conservative therapy regardless of whether MRI is overutilized. OP8 scores may be worse for institutions with aggressive control of inappropriate imaging.

Therapeutic impact of CT of the appendix in a community hospital emergency department.

OBJECTIVE: The purpose of this study was to prospectively evaluate the therapeutic impact of CT of the appendix in a community hospital. SUBJECTS AND METHODS: For each of 100 consecutive adult patients who presented to a community hospital emergency department from August 2006 to November 2006 and underwent CT of the appendix, the proposed treatment plan and the likelihood of appendicitis were recorded before CT and were compared with the actual treatment after CT. The primary outcome assessed was change in patient management after CT. The percentage likelihood of appendicitis, whether patient disposition changed after CT, and the presence or absence of appendicitis were examined. The accuracy of CT was also calculated. RESULTS: The treatment plans of the emergency clinicians changed in 29 patients (29%). Appendicitis was ruled out on the basis of CT findings in 50% (9/18) of patients when appendicitis was considered probable and in 60% (3/5) when appendicitis was considered very likely. When appendicitis was considered unlikely, appendicitis was ruled out by CT in 100% (20/20) of patients. CT of the appendix was shown to have high sensitivity (94%), specificity (100%), positive predictive value (100%), negative predictive value (99%), and accuracy (99%). CONCLUSION: CT of the appendix had an important therapeutic impact on patients presenting to a community hospital emergency department. The data suggest that CT can be withheld in patients in whom emergency clinicians rate the likelihood of appendicitis as unlikely but that CT findings are often of benefit even when appendicitis is judged to be very likely.

Multidetector computed tomography pulmonary angiography: does arm position affect pulmonary artery enhancement?

OBJECTIVE: To evaluate whether arm position affects pulmonary artery enhancement in computed tomographic pulmonary angiography (CTPA). METHODS: Study protocol had local ethics committee approval. Eighty-six patients who received 16 detector row CTPA for suspected pulmonary embolism were scanned with their contrast-injected arm resting at their side and compared with 94 patients who were scanned with both arms resting above their head. Two radiologists assessed pulmonary artery enhancement with a region-of-interest measurement of the main pulmonary artery density, scored the degree of beam-hardening artifact arising from the superior vena cava (SVC) and from the dependent arm that crossed the pulmonary arteries (1 = no artifact, 5 = artery obscured), and measured the degree of central venous compression of the injected veins at the thoracic inlet. A 2-tailed t test was performed to compare pulmonary artery density and central venous compression. RESULTS: There was no difference in pulmonary artery enhancement between the 2 arm positions. Mean density of contrast in the main pulmonary artery was 329 Hounsfield units (HU) (95% confidence interval (CI), 310-350) in the arm-down group, compared with 325 HU (95% CI, 306-346) in the arm-up group (P = 0.65). Greater compression of the central veins occurred in the arm-up group (48.5%; 95% CI, 42.3%-54.8%) than in the arm-down group (22.3%; 95% CI, 16.8%-27.8%) (P < 0.05). There was also more beam hardening arising from contrast in the SVC in the arm-up group (P < 0.0001). CONCLUSIONS: Arm position does not affect pulmonary arterial enhancement during CTPA. There was greater central venous compression and more beam-hardening artifact arising from the SVC when the arm was held above the head.

Indeterminate CT angiography in blunt thoracic trauma: is CT angiography enough?

OBJECTIVE: The primary objective of our study was to determine whether catheter angiography is needed to exclude aortic and intrathoracic great vessel injury when CT angiography (CTA) findings are indeterminate (mediastinal hematoma without direct evidence of aortic or intrathoracic great vessel injury). The secondary objective was to devise a classification scheme for mediastinal hematomas. MATERIALS AND METHODS: This study is a retrospective analysis of patients presenting with blunt trauma over 4.5 years at a level 1 trauma center. Indeterminate CTA findings in patients with blunt injury were identified through a database search of imaging reports. CTA findings and final outcomes, including catheter angiography and clinicopathologic records, were reviewed independently by blinded observers. RESULTS: One hundred seven patients (age range, 11-88 years) met the inclusion criteria. Seventy-two (age range, 15-88 years) had a reference standard of subsequent catheter angiography, and 35 subjects (age range, 11-87 years) did not undergo catheter angiography and therefore had a reference standard of clinicopathologic review. No subjects with isolated mediastinal hematoma on CTA had aortic or intrathoracic great vessel injury, for a positive predictive value of 0% (95% CI, 0-0.028). Using our proposed classification scheme, we found a direct correlation between the percentage of cases that underwent catheter angiography and hematoma severity. CONCLUSION: When CTA is indeterminate in blunt thoracic trauma, conventional angiography is unlikely to show an aortic or intrathoracic great vessel injury and may be unnecessary. A grading system for mediastinal hematomas could help triage patients to conventional angiography when further imaging is desired.