ASSESSMENT OF ABNORMAL SKELETAL MUSCLE PERFUSION BY CONTRAST-ENHANCED ULTRASOUND WITH PARAMETRIC IMAGING IN RATS AFTER SEVERE INJURY, HEMORRHAGIC SHOCK, AND WHOLE BLOOD RESUSCITATION.

ABSTRACT: Background: After severe injury, optical measures of microvascular blood flow (MBF) decrease and do not normalize with resuscitation to normal blood pressure. These changes are associated with organ dysfunction, coagulopathy, and death. However, the pathophysiology is not well understood. Several possible pathways could also contribute to the development of trauma-induced coagulopathy (TIC). A small-animal model of trauma-related MBF derangement that persists after resuscitation and includes TIC would facilitate further study. Parametric contrast-enhanced ultrasound (CEUS) is particularly advantageous in this setting, because it noninvasively assesses MBF in large, deep vascular beds. We sought to develop such a model, measuring MBF with CEUS. Methods: Sixteen male Sprague-Dawley rats were anesthetized, ventilated, and cannulated. Rats were subjected to either no injury (sham group) or a standardized polytrauma and pressure-targeted arterial catheter hemorrhage with subsequent whole blood resuscitation (trauma group). At prespecified time points, CEUS measurements of uninjured quadriceps muscle, viscoelastic blood clot strength, and complete blood counts were taken. Results: After resuscitation, blood pressure normalized, but MBF decreased and remained low for the rest of the protocol. This was primarily driven by a decrease in blood volume with a relative sparing of blood velocity. Viscoelastic blood clot strength and platelet count also decreased and remained low throughout the protocol. Conclusion: We present a rat model of MBF derangement in uninjured skeletal muscle and coagulopathy after polytrauma that persists after resuscitation with whole blood to normal macrohemodynamics. Parametric CEUS analysis shows that this change is primarily due to microvascular obstruction. This platform can be used to develop a deeper understanding of this important process.

Cholecystitis and Cholangitis during Continuous Renal Replacement Therapy in a Patient with Retroperitoneal Hemorrhage Requiring Large Amounts of Contrast Medium for the Assessment and Intervention.

Intravenous use of contrast medium (CM), which may cause kidney dysfunction, is admissible for hemodialysis patients because of the efficient removal by hemodialysis. We herein report a 61-year-old woman on hemodialysis who suffered from cholecystitis and cholangitis after large-volume CM administration during continuous renal replacement therapy. After catheter ablation, she developed life-threatening retroperitoneal hemorrhage, which led to the use of 500 mL CM for 5 consecutive days. It should be kept in mind that excessive vicarious CM excretion in the biliary system may become a predisposing factor of cholecystitis and cholangitis in patients who frequently undergo radiological interventions and imaging.

Assessment of intramyocardial hemorrhage with dark-blood T2*-weighted cardiovascular magnetic resonance.

BACKGROUND: Intramyocardial hemorrhage (IMH) within myocardial infarction (MI) is associated with major adverse cardiovascular events. Bright-blood T2*-based cardiovascular magnetic resonance (CMR) has emerged as the reference standard for non-invasive IMH detection. Despite this, the dark-blood T2*-based CMR is becoming interchangeably used with bright-blood T2*-weighted CMR in both clinical and preclinical settings for IMH detection. To date however, the relative merits of dark-blood T2*-weighted with respect to bright-blood T2*-weighted CMR for IMH characterization has not been studied. We investigated the diagnostic capacity of dark-blood T2*-weighted CMR against bright-blood T2*-weighted CMR for IMH characterization in clinical and preclinical settings. MATERIALS AND METHODS: Hemorrhagic MI patients (n = 20) and canines (n = 11) were imaged in the acute and chronic phases at 1.5 and 3 T with dark- and bright-blood T2*-weighted CMR. Imaging characteristics (Relative signal-to-noise (SNR), Relative contrast-to-noise (CNR), IMH Extent) and diagnostic performance (sensitivity, specificity, accuracy, area-under-the-curve, and inter-observer variability) of dark-blood T2*-weighted CMR for IMH characterization were assessed relative to bright-blood T2*-weighted CMR. RESULTS: At both clinical and preclinical settings, compared to bright-blood T2*-weighted CMR, dark-blood T2*-weighted images had significantly lower SNR, CNR and reduced IMH extent (all p < 0.05). Dark-blood T2*-weighted CMR also demonstrated weaker sensitivity, specificity, accuracy, and inter-observer variability compared to bright-blood T2*-weighted CMR (all p < 0.05). These observations were consistent across infarct age and imaging field strengths. CONCLUSION: While IMH can be visible on dark-blood T2*-weighted CMR, the overall conspicuity of IMH is significantly reduced compared to that observed in bright-blood T2*-weighted images, across infarct age in clinical and preclinical settings at 1.5 and 3 T. Hence, bright-blood T2*-weighted CMR would be preferable for clinical use since dark-blood T2*-weighted CMR carries the potential to misclassify hemorrhagic MIs as non-hemorrhagic MIs.

Radiological assessment of response and adverse events associated with novel systemic oncological therapies.

The last decade has seen a paradigm shift in medical oncology treatment with the rise of novel systemic agents, principally molecular targeted therapy and immunotherapy. These new groups of anti-cancer treatment have revolutionised the prognostic landscape for certain patient cohorts with advanced disease, and it is hoped that through ongoing extensive clinical research, significant survival benefits may be demonstrated in the majority of tumour types. However, radiological response assessment of these new agents has become more nuanced for radiologists, as the behaviour of both responding and progressing tumour burden can be more diverse than with conventional chemotherapy. Additionally, radiologists need to be aware of adverse events associated with these treatments as some side effects carry a high morbidity/mortality and may manifest radiologically before they become clinically apparent. This review discusses radiological response assessment and adverse events associated with these novel agents, which have become fundamental aspects of systemic oncological therapy.

Use of point-of-care ultrasound for the assessment of intravascular volume in five rural New Zealand hospitals.

INTRODUCTION: Measuring the diameter of the inferior vena cava (IVC) or the height of the jugular venous pressure (JVP) with point-of-care ultrasound (POCUS) is a practical alternative method for estimating a patient's intravascular volume in the rural setting. This study aims to determine whether or not POCUS of the IVC or JVP generates additional useful clinical information over and above routine physical examination in this context. METHODS: Twenty generalist physicians, working in five New Zealand rural hospitals, recorded their estimation of a patient's intravascular volume based on physical examination and then again after performing POCUS of the IVC or JVP, using a visual scale from 1 to 11. RESULTS: Data were available for 150 assessments. There was an only moderate agreement between the pre- and post-test findings (Spearman's correlation coefficient = 0.46). In 28% (42/150) of cases, the difference was four or more points on the scale, and therefore, had the potential to be clinically significant. CONCLUSION: In the rural context, POCUS provides new information that frequently alters the clinician's estimation of a patient's intravascular volume.

Résumé Introduction: La mesure du diamètre de la veine cave inférieure ou de la hauteur de la pression veineuse jugulaire à l'aide de l'échographie au point de service est une méthode pratique pour estimer le volume intravasculaire d'un patient en région rurale. Cette étude vise à déterminer si oui ou non l'échographie au point de service de la veine cave inférieure ou de la pression veineuse jugulaire génère un surcroît d'information clinique utile par rapport à l'examen physique de routine dans ce contexte. Méthodologie: Vingt médecins généralistes de 5 hôpitaux des régions rurales de la Nouvelle-Zélande ont noté sur une échelle visuelle de 1 à 11 leur estimation du volume intravasculaire des patients basée sur l'examen physique, puis après une échographie au point de service de la veine cave inférieure ou de la pression veineuse jugulaire. Résultats: Des données se rapportant à 150 évaluations étaient disponibles. La concordance entre les résultats d'avant le test et d'après le test n'était que modérée (coefficient de corrélation de Spearman = 0,46). Dans 28 % (42/150) des cas, la différence était de quatre points ou plus sur l'échelle et avait donc le potentiel d'être cliniquement significative. Conclusion: En contexte rural, l'échographie au point de service fournit de nouveaux renseignements qui altèrent fréquemment l'estimation du volume intravasculaire par le clinicien. Mots-clés: Échographie, évaluation du volume, point de service, rural, veine cave inférieure.

Spontaneous Retroperitoneal and Rectus Sheath Hemorrhage-Management, Risk Factors and Outcomes.

BACKGROUND: Spontaneous retroperitoneal and rectus sheath hemorrhage (SRRSH) is associated with high mortality in the literature, but studies on the subject are lacking. The objective of this study was to identify early predictors of the need for angiographic or surgical intervention (ASI) in patients with SRRSH and define risk factors for mortality. METHODS: We conducted a retrospective cohort study at a tertiary academic hospital. All patients with computed tomography-identified SRRSH between 2012 to 2017 were included. Exclusion criteria were age below 18 years, possible mechanical cause of SRRSH, aortic aneurysm rupture or dissection, and traumatic or iatrogenic sources of SRRSH. The primary outcome was the incidence of ASI and/or mortality. RESULTS: Of 100 patients included (median age 70 years, 52% males), 33% were transferred from another hospital, 82% patients were on therapeutic anticoagulation, and 90% had serious comorbidities. Overall mortality was 22%, but SRRSH-related mortality was only 6%. Sixteen patients underwent angiographic intervention (n = 10), surgical intervention (n = 5), or both (n = 1). Flank pain (OR 4.15, 95% CI 1.21-14.16, p = 0.023) and intravenous contrast extravasation (OR 3.89, 95% CI 1.23-12.27, p = 0.020) were independent predictors of ASI. Transfer from another hospital (OR 3.72, 95% CI 1.30-10.70, p = 0.015), age above 70 years (OR 4.24, 95% CI 1.25-14.32, p = 0.020), and systolic blood pressure below 110 mmHg at the time of diagnosis (OR 4.59, 95% CI 1.19-17.68, p = 0.027) were independent predictors of mortality. CONCLUSIONS: SRRSH is associated with high mortality but is typically not the direct cause. Most SRRSHs are self-limited and require no intervention. Pattern identification of ASI is hard.

A benchmark approach to hemorrhage risk management of cavernous malformations.

OBJECTIVE: Despite the low annual risk of hemorrhage associated with a cavernous malformation (CM) (0.6%-1.1% per year), the risk of rehemorrhage rate and severity of neurologic deficits is significantly higher; therefore, we aimed to evaluate the rupture risk of CMs depending on various factors. METHODS: We retrospectively analyzed medical records of all patients with CM admitted to our institution between 1999 and April 2016. Cavernoma volume, location of the lesion, existence of a developmental venous anomaly (DVA), number of cavernomas, and patient characteristics (sex, age, hypertension, and antithrombotic therapy) were assessed. RESULTS: One hundred fifty-four patients with CM were included; 89 (58%) ruptured CMs were identified. In statistical univariable analysis, the existence of a DVA was significantly higher in the ruptured cavernoma group (p < 0.001; odds ratio [OR] 4.6). A multivariable analysis of all included independent risk factors designated young age (<45 years) (p < 0.05; OR 2.2), infratentorial location (p < 0.01; OR 2.9), and existence of a DVA (p < 0.0001; OR 4.7) with significantly higher risk of rupture in our patient cohort. A separate analysis of these anatomical locations, supratentorial vs infratentorial, indicated that the existence of a DVA (p < 0.01; OR 4.16) in ruptured supratentorial cases and CM volume (≥1 cm3) (p < 0.0001; OR 3.5) in ruptured infratentorial cases were significant independent predictors for hemorrhage. CONCLUSIONS: Young age (<45 years), infratentorial location, and the presence of a DVA are associated with a higher hemorrhage risk. CM volume (≥1 cm3) and the existence of a DVA were independently in accordance with the anatomical location high risk factors for CM rupture.

The influence of microvascular injury on native T1 and T2* relaxation values after acute myocardial infarction: implications for non-contrast-enhanced infarct assessment.

OBJECTIVES: Native T1 mapping and late gadolinium enhancement (LGE) imaging offer detailed characterisation of the myocardium after acute myocardial infarction (AMI). We evaluated the effects of microvascular injury (MVI) and intramyocardial haemorrhage on local T1 and T2* values in patients with a reperfused AMI. METHODS: Forty-three patients after reperfused AMI underwent cardiovascular magnetic resonance imaging (CMR) at 4 [3-5] days, including native MOLLI T1 and T2* mapping, STIR, cine imaging and LGE. T1 and T2* values were determined in LGE-defined regions of interest: the MI core incorporating MVI when present, the core-adjacent MI border zone (without any areas of MVI), and remote myocardium. RESULTS: Average T1 in the MI core was higher than in the MI border zone and remote myocardium. However, in the 20 (47%) patients with MVI, MI core T1 was lower than in patients without MVI (MVI 1048±78ms, no MVI 1111±89ms, p=0.02). MI core T2* was significantly lower in patients with MVI than in those without (MVI 20 [18-23]ms, no MVI 31 [26-39]ms, p<0.001). CONCLUSION: The presence of MVI profoundly affects MOLLI-measured native T1 values. T2* mapping suggested that this may be the result of intramyocardial haemorrhage. These findings have important implications for the interpretation of native T1 values shortly after AMI. KEY POINTS: • Microvascular injury after acute myocardial infarction affects local T1 and T2* values. • Infarct zone T1 values are lower if microvascular injury is present. • T2* mapping suggests that low infarct T1 values are likely haemorrhage. • T1 and T2* values are complimentary for correctly assessing post-infarct myocardium.

Focused assessment with sonography for trauma (FAST) versus multidetector computed tomography in hemodynamically unstable emergency patients. / ¿Eco-FAST o tomografía computarizada multidetectora en el paciente hemodinámicamente inestable tras traumatismo de urgencias?

This critically appraised topic (CAT) study aims to evaluate the quality and extent of the scientific evidence that supports the use of focused assessment with sonography for trauma (FAST) versus multidetector computed tomography (MDCT) in hemodynamically unstable trauma patients in the emergency room. An efficient search of the literature yielded several recent articles with a high level of evidence. The CAT study concludes that FAST is an acceptable initial imaging test in hemodynamically unstable patients, although its performance is limited in certain circumstances. The decision whether to use MDCT should be determined by evaluating the patient's degree of instability and the distance to the MDCT scanner. Nevertheless, few articles address the question of the distance to MDCT scanners in emergency departments.

Comparison of elastography, contrast-enhanced ultrasonography, and computed tomography for assessment of lesion margin after radiofrequency ablation in livers of healthy dogs.

OBJECTIVE To assess by use of various diagnostic imaging modalities acute changes in livers of healthy dogs after radiofrequency ablation (RFA) and determine the capability of each imaging modality to monitor ablation lesion changes. ANIMALS 6 healthy Beagles. PROCEDURES 12 ablation lesions were created in the liver of the dogs (2 lesions/dog). Ablation lesions were evaluated by use of conventional ultrasonography, strain elastography, and contrast-enhanced ultrasonography immediately after (time 0), 30 to 60 minutes after, and 3 days after RFA, and by use of CT 30 minutes and 3 days after RFA. Three dogs were euthanized shortly after RFA, and the other 3 dogs were euthanized on day 3. Lesion size measured by each imaging modality was compared with necropsy findings. RESULTS Immediately after RFA, clear margins were more visible with elastography and contrast-enhanced ultrasonography than with conventional ultrasonography, which had acoustic shadowing. On triphasic contrast CT, the ablation zone, which indicated necrosis and hemorrhage, was not enhanced and could be measured. Marked enhancement of the periablation rim was observed during the venous phase and was identified as granulation tissue. Size of the ablation area measured on enhanced CT images was strongly correlated with actual lesion size. CONCLUSIONS AND CLINICAL RELEVANCE For dogs of this study, CT was the most reliable method for lesion size determination. Although ultrasonographic imaging measurements underestimated lesion size, all modalities could be used to provide additional real-time guidance for RFA procedures of the liver as well as for other RFA procedures.

The role of left ventricular deformation in the assessment of microvascular obstruction and intramyocardial haemorrhage.

In the setting of acute ST-elevation myocardial infarction (STEMI), it remains unclear which strain parameter most strongly correlates with microvascular obstruction (MVO) or intramyocardial haemorrhage (IMH). We aimed to investigate the association of MVO, IMH and convalescent left ventricular (LV) remodelling with strain parameters measured with cardiovascular magnetic resonance (CMR). Forty-three patients with reperfused STEMI and 10 age and gender matched healthy controls underwent CMR within 3-days and at 3-months following reperfused STEMI. Cine, T2-weighted, T2*-imaging and late gadolinium enhancement (LGE) imaging were performed. Infarct size, MVO and IMH were quantified. Peak global longitudinal strain (GLS), global radial strain (GRS), global circumferential strain (GCS) and their strain rates were derived by feature tracking analysis of LV short-axis, 4-chamber and 2-chamber cines. All 43 patients and ten controls completed the baseline scan and 34 patients completed 3-month scans. In multivariate regression, GLS demonstrated the strongest association with MVO or IMH (beta = 0.53, p < 0.001). The optimal cut-off value for GLS was -13.7% for the detection of MVO or IMH (sensitivity 76% and specificity 77.8%). At follow up, 17% (n = 6) of patients had adverse LV remodeling (defined as an absolute increase of LV end-diastolic/end-systolic volumes >20%). Baseline GLS also demonstrated the strongest diagnostic performance in predicting adverse LV remodelling (AUC = 0.79; 95% CI 0.60-0.98; p = 0.03). Post-reperfused STEMI, baseline GLS was most closely associated with the presence of MVO or IMH. Baseline GLS was more strongly associated with adverse LV remodelling than other CMR parameters.

Visual Assessment of the Intensity and Pattern of T1 Hyperintensity on MRI to Differentiate Hemorrhagic Renal Cysts From Renal Cell Carcinoma.

OBJECTIVE: The purpose of this study was to apply a visual assessment of the intensity and pattern of T1 hyperintensity at MRI to differentiate hemorrhagic renal cysts from renal cell carcinoma (RCC). MATERIALS AND METHODS: A total of 144 T1-hyperintense renal lesions (62 cysts, all showing no enhancement on subtracted contrast-enhanced images and either 2-year stability or unenhanced CT density > 70 HU, and 82 histologically confirmed RCCs) in 144 patients were included. Two radiologists independently characterized qualitative features of the T1 hyperintensity in each lesion on unenhanced T1-weighted images. An additional radiologist placed ROIs to measure lesions' T1 signal intensity normalized to that of the psoas muscle. Chi-square and unpaired t tests were performed to compare the pattern of T1 hyperintensity between groups. RESULTS: The T1 hyperintensity was considered marked in 62.9% of cysts and 17.1% of RCCs for reader 1 and in 46.8% of cysts and 8.5% of RCCs for reader 2 (p < 0.001). The T1 hyperintensity exhibited a diffusely homogeneous distribution in 88.7% of cysts and 7.3% of RCCs for reader 1 and in 72.6% of cysts and 4.9% of RCCs for reader 2 (p < 0.001). The combination of both diffusely homogeneous distribution and marked degree of T1 hyperintensity achieved sensitivities of 40.3-56.5%, specificities of 97.6-98.8%, and accuracies of 73.6-79.9% for the diagnosis of T1-hyperintense cysts. The two cases of RCC exhibiting this imaging pattern for at least one reader were both papillary RCCs. Normalized signal intensity was 2.39 ± 0.99 in T1-hyperintense cysts versus 2.12 ± 0.84 in T1-hyperintense RCCs (p = 0.088). CONCLUSION: Diffuse T1 hyperintensity, particularly when marked, strongly indicates a hemorrhagic cyst rather than an RCC. Deferral of follow-up imaging may be considered when this imaging appearance is encountered at unenhanced MRI.

Assessment of Hemophilic Arthropathy by Ultrasound: Where Do We Stand?

Joint hemorrhages represent the most common type of bleeding episode in persons with hemophilia, and recurrent hemarthrosis triggers chronic arthropathy, which is the most frequent chronic complication in these patients. In recent years, in the frame of a comprehensive care approach, a growing attention has been given to the periodic assessment of the joint status in hemophilia patients with the aim to identify early arthropathic changes and to prevent the development of a clinically overt arthropathy. Besides clinical examination, X-ray and magnetic resonance imaging (MRI) are currently used to evaluate joint status and to monitor the disease progression in hemophilia. Considering the limitations of X-ray and MRI, growing interest has been given to ultrasound (US) as a possible tool to assess joint status and identify early arthropathic changes in hemophilia patients. In the present review, we summarize major literature evidence on the use of joint US for the evaluation of markers of disease activity (joint effusion and synovial hypertrophy) and of degenerative damages (osteochondral changes) in patients with hemophilia. On the whole, being able to identify the presence of intra- or extra-articular fluid, US examination is the fastest and most reliable technique to identify acute conditions, such as hemarthrosis. In addition, the information on joint involvement provided by US in the patient follow-up may influence treatment decisions on a personalized basis. The use of US as part of a routine clinical examination by hemophilia experts may optimize the diagnostic workflow, avoiding additional costs and long waiting lists for patients referred to imaging departments. In the frame of a comprehensive care approach, US might represent a strategy to early detect and monitor synovial hypertrophy and osteochondral changes in hemophilia, thus extending the clinical examination and helping identify joints to be studied with a second-level examination such as MRI.

The Face, Content, and Construct Validity Assessment of a Focused Assessment in Sonography for Trauma Simulator.

OBJECTIVE: Hemorrhage identification in trauma care is a major priority. Focused assessment in sonography for trauma (FAST) offers a rapid, reliable means of detecting torso bleeding. The aims of this study were to conduct a face, content, and construct validity assessment of a FAST simulator and establish a rigorous assessment tool. DESIGN: Participants were requested to perform a FAST scan and state if any abnormality was found in each region. Metrics evaluated included time, errors, and missed targets. Accuracy of images obtained was assessed by 2 independent radiologists. Experts completed a face and content validity questionnaire at the end of the study. SETTING: The study took place in the simulation suite within the Academic Surgical Unit of the Department of Surgery and Cancer. PARTICIPANTS: Novices had no prior experience with ultrasound, intermediates had less than 6 months experience with fewer than 50 FAST scans performed, and experts had more than 1 year of experience with greater than 100 FAST scans performed. There were 31 participants: 11 experts, 10 intermediates, and 10 novices. RESULTS: The face and content validity questionnaire scored high marks across all categories and achieved an overall median realism score of 8 ± 1.5 on a Likert scale. Experts performed the FAST scan faster with more accuracy and fewer errors than other cohorts (p < 0.001). Both the novices and intermediates were the slowest, least accurate, and either missed or made the most errors when scanning the lung bases and spleen. CONCLUSIONS: This study has established the face, content, and construct validities of a FAST simulator, which could be used to accelerate training for novices. Additionally, it has demonstrated a rigorous method for FAST assessment, which has proven to be effective and in doing so addressed some of the criticisms leveled against it.

Do women with pain and bleeding in early pregnancy require a vaginal speculum examination as part of their assessment?

AIMS: To investigate whether a vaginal speculum examination (VSE) prior to a transvaginal scan (TVS) alters the diagnosis or management of women who complain of bleeding in early pregnancy. METHODS: A prospective study. Women were asked to describe their bleeding as heavy, moderate or light and to consent to VSE prior to TVS. TVS was performed to obtain a final diagnosis of pregnancy outcome. RESULTS: 221 consecutive women were included in the study. In 14.5% (n = 32) complaining of heavy bleeding, blood was seen in all but two VSE and 84% (n = 27) had a miscarriage diagnosed by TVS. Products of conception were removed in 18.8% (n = 6), but this did not alter the subsequent immediate management of any cases. 65.2% (n = 144) of women complained of light bleeding, blood was seen on VSE in 53% (n = 77). Of these women, 25% (n = 19) of those where blood was seen had a miscarriage, compared to 6% (n = 4) of women where blood was not seen. A cervical ectropion was visualised in 11.7% (n = 26) and 2.3% (n = 5) had a cervical polyp. No other clinically significant pathology was detected. CONCLUSION: The amount of bleeding reported by women in early pregnancy relates well with VSE findings. Performing a VSE did not alter the subsequent management of these patients. This study demonstrates that routine objective assessment of blood by a clinician performing VSE prior to a TVS is unnecessary.

Utility of simultaneous interventional radiology and operative surgery in a dedicated suite for seriously injured patients.

PURPOSE OF REVIEW: In recent years, combined interventional radiology and operative suites have been proposed and are now becoming operational in select trauma centres. Given the infancy of this technology, this review aims to review the rationale, benefits and challenges of hybrid suites in the management of seriously injured patients. RECENT FINDINGS: No specific studies exist that investigate outcomes within hybrid trauma suites. Endovascular and interventional radiology techniques have been successfully employed in thoracic, abdominal, pelvic and extremity trauma. Although the association between delayed haemorrhage control and poorer patient outcomes is intuitive, most supporting scientific data are outdated. The hybrid suite model offers the potential to expedite haemorrhage control through synergistic operative, interventional radiology and resuscitative platforms. Maximizing the utility of these suites requires trained multidisciplinary teams, ergonomic and workplace considerations, as well as a fundamental paradigm shift of trauma care. This often translates into a more damage-control orientated philosophy. SUMMARY: Hybrid suites offer tremendous potential to expedite haemorrhage control in trauma patients. Outcome evaluations from trauma units that currently have operational hybrid suites are required to establish clearer guidelines and criteria for patient management.

Purposeful variable selection and stratification to impute missing Focused Assessment with Sonography for Trauma data in trauma research.

BACKGROUND: The Focused Assessment with Sonography for Trauma (FAST) examination is an important variable in many retrospective trauma studies. The purpose of this study was to devise an imputation method to overcome missing data for the FAST examination. Owing to variability in patients' injuries and trauma care, these data are unlikely to be missing completely at random, raising concern for validity when analyses exclude patients with missing values. METHODS: Imputation was conducted under a less restrictive, more plausible missing-at-random assumption. Patients with missing FAST examinations had available data on alternate, clinically relevant elements that were strongly associated with FAST results in complete cases, especially when considered jointly. Subjects with missing data (32.7%) were divided into eight mutually exclusive groups based on selected variables that both described the injury and were associated with missing FAST values. Additional variables were selected within each group to classify missing FAST values as positive or negative, and correct FAST examination classification based on these variables was determined for patients with nonmissing FAST values. RESULTS: Severe head/neck injury (odds ratio [OR], 2.04), severe extremity injury (OR, 4.03), severe abdominal injury (OR, 1.94), no injury (OR, 1.94), other abdominal injury (OR, 0.47), other head/neck injury (OR, 0.57), and other extremity injury (OR, 0.45) groups had significant ORs for missing data; the other group's OR was not significant (OR, 0.84). All 407 missing FAST values were imputed, with 109 classified as positive. Correct classification of nonmissing FAST results using the alternate variables was 87.2%. CONCLUSION: Purposeful imputation for missing FAST examinations based on interactions among selected variables assessed by simple stratification may be a useful adjunct to sensitivity analysis in the evaluation of imputation strategies under different missing data mechanisms. This approach has the potential for widespread application in clinical and translational research, and validation is warranted.