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Ultrasonography is an established modality in medical imaging and is evermore entering clinical practice. This chapter provides an introduction to the principles of clinical ultrasonography. It describes the use of airway ultrasonography for identification of the cricothyroid membrane, the trachea and for confirming correct tracheal intubation. Bedside ultrasonography by the anaesthetist has a much higher success rate than palpation for identifying the cricothyroid membrane, especially in patients with neck pathology. It should be applied before initiation of airway management and not be delayed until airway problems are apparent. The role of lung ultrasonography for identification of normal ventilation and pathology is described. Gastric ultrasonography for assessing the starvation status of a patient is described.
Pulmonary embolism is a clinical condition with high mortality rates in all age groups. The treatment includes anticoagulation and fibrinolytic therapy, and clinical management is challenging in cases of bleeding diathesis. Sepsis-induced coagulopathy (SIC), which has been recently defined to cause disruption of coagulation cascade accompanied by organ dysfunctions, is regarded as a major cause of mortality. It is noteworthy that there is no decrease in fibrinogen levels, unlike disseminated intravascular coagulopathy (DIC). This study aimed to present the management of a 70-year-old female patient who was admitted to emergency department with atypical complaints and diagnosed with pulmonary embolism due to deep vein thrombosis and septic shock. The clinical success of fibrinolytic therapy following the administration of fresh frozen plasma (FFP), although the patient had elevated international normalized ratio (INR), is presented in this case report. Since elevated INR and thrombocytopenia, which are observed in SIC, are caused by the inhibition of fibrinolysis, fibrinolytic therapy can be a rational treatment choice considering the profit/loss rate.
Although the gross and microscopic pathology in rats infected with Angiostrongylus cantonensis has been well described, corresponding changes detected using diagnostic imaging modalities have not been reported. This work describes the cardiopulmonary changes in mature Wistar rats chronically infected with moderate burdens of A. cantonensis using radiology, computed tomography (CT), CT angiography, echocardiography, necropsy and histological examinations. Haematology and coagulation studies were also performed. Thoracic radiography, CT and CT angiography showed moderately severe alveolar pulmonary patterns mainly affecting caudal portions of the caudal lung lobes and associated dilatation of the caudal lobar pulmonary arteries. Presumptive worm profiles could be detected using echocardiography, with worms seen in the right ventricular outflow tract or straddling either the pulmonary and/or the tricuspid valves. Extensive, multifocal, coalescing dark areas and multiple pale foci affecting the caudal lung lobes were observed at necropsy. Histologically, these were composed of numerous large, confluent granulomas and fibrotic nodules. Adult worms were found predominantly in the mid- to distal pulmonary arteries. An inflammatory leukogram, hyperproteinaemia and hyperfibrinogenaemia were found in most rats. These findings provide a comparative model for A. cantonensis in its accidental hosts, such as humans and dogs. In addition, the pathological and imaging changes are comparable to those seen in dogs infected with Angiostrongylus vasorum, suggesting rats infected with A. cantonensis could be a model for dogs with A. vasorum infection.
Focused assessment with sonography for trauma (FAST) has been incorporated into the initial evaluation of trauma for decades. It is an important screening tool in the detection of intra-abdominal fluid. The objective of this study was to perform a systematic review of the use and accuracy of FAST as an imaging tool for blunt abdominal trauma in disaster/mass casualty settings. A systematic review of literature was conducted using key words and search terms. Two independent reviewers screened abstracts to determine inclusion using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). For studies passing QUADAS, a meta-analysis was performed calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). FAST results were compared with the gold standard, which was a combination of CT scan results, operative findings, and medical records of the clinical course. Initial database screening resulted in 133 articles, of which 21 were selected for QUADAS evaluation. Five studies passed QUADAS and were selected in the final meta-analysis, with a total of 4263 patients. The sensitivity of FAST was 92.1% (87.8–95.6), specificity 98.7% (96.0–99.9), PPV 90.7% (70.0–98.0), and NPV 98.8% (98.1–99.5) for the detection of intra-abdominal injury. In our meta-analysis, FAST was both sensitive and specific in the evaluation of trauma in the disaster setting.
This research communication aims to test the hypothesis that B-Mode, colour Doppler ultrasonographic measurements and characteristics can identify mastitis in dairy cows. A total of 102 lactating cows were divided into 3 groups: cows in which all mammary quarters were CMT-negative, cows with CMT-positive mammary quarters and cows with clinical mastitis in at least one quarter. Colour Doppler ultrasonography measurements of the supramammary lymph nodes revealed that distortion-type vascular morphology, the rate of type 4 vascular densities and the incidence of mixed-type vascular distributions were highest in the clinical mastitis group, whereas the frequency of avascularity in supramammary lymph nodes was highest in the CMT-negative group. All differences were significant. In conclusion, the use of B-mode and colour Doppler ultrasonographic measurements of the supramammary lymph nodes can provide useful information about the current condition of mastitis in cows, although its diagnostic potential remains to be determined.
A 6-year-old patient was diagnosed with an arteriovenous fistula in the neck region. Non-invasive three-dimensional imaging, including computed tomography and ultrasonography, was used for guidance of percutaneous closure of the fistula and evaluation of the final outcome.
Lung ultrasound has value in diagnosing dyspnea. The main objective of this study was to evaluate the accuracy of a modified lung ultrasound (MLUS) score to predict the severity of acute dyspnea in elderly patients.
This was an observational single-centre study including patients over age 64 admitted to the emergency department for acute dyspnea with hypoxia. Participants had an early lung ultrasound performed by a dedicated emergency physician, followed by the usual care by a team blinded to the lung ultrasound results. Patients were allocated by disposition to either a critical care (CC) group (patients who needed admission to the intensive care unit [ICU] and/or who died within 48 h) or a standard care group.
Among 137 patients analysed (mean age 79 ± 13 years, 74 [54%] women), 43 (31%) were categorized into the CC group. The time taken to obtain the MLUS was 30 ± 22 min. The area under the receiver operating characteristic curve of the MLUS for predicting the CC group was 0.97 (0.92–0.99; p < 0.01) with a cut-off set strictly above 17 for 93% sensitivity (81–99), 99% specificity (94–100), a positive predictive value of 98% (87–100), a negative predictive value of 97% (91–99), a positive likelihood ratio of 86, a negative likelihood ratio of 0.07, and a diagnostic accuracy of 97% (93–99). In a multivariate analysis, the MLUS was the only independent associated factor for the CC group.
An early lung ultrasound score can predict the need for ICU admission and/or death within 48 hours in elderly dyspneic patients.
Editor’s note: CJEM has partnered with a small group of selected journals of international emergency medicine societies to share from each a highlighted research study, as selected monthly by their editors. Our goals are to increase awareness of our readership to research developments in the international emergency medicine literature, promote collaboration among the selected international emergency medicine journals, and support the improvement of emergency medicine world-wide, as described in the WAME statement at http://www.wame.org/about/policy-statements#Promoting%20Global%20Health. Abstracts are reproduced as published in the respective participating journals and are not peer reviewed or edited by CJEM.
Point-of-Care Ultrasound (POCUS) has become an important diagnostic tool for hospital-based clinicians. This study assesses the role of POCUS at Pemberton Music Festival 2016 (Pemberton, British Columbia [BC], Canada), a remote mass gathering where physicians face limited resources, complex disposition decisions, and a dynamic clinical environment.
This study prospectively evaluated the impact of POCUS on patient diagnosis, management, and disposition based on the self-report of the study physicians. The authors hypothesized that having ultrasound available for use would aid in diagnostic and management decisions and would reduce the need to transfer patients off-site to other health care facilities, reducing impact on the acute health services in the host community.
A handheld ultrasound was available for use by physicians in the main medical tent. All participating physicians self-reported their training and comfort using POCUS. After each POCUS scan, physicians completed a survey and recorded the indication for use, scans performed, and impact on patient diagnosis, management, and disposition.
In total, POCUS was used on 28 of the 686 patients treated in the main medical tent; POCUS was reported to narrow the differential diagnosis in 64% of cases and altered the working diagnosis in 21% of cases. Its use changed the management plan in 39% of patients. Its use was reported to reduce the burden on broader health care resource utilization in 46% of cases and prevented ambulance transport off-site in 32% of cases (nine cases in total). This corresponded to an absolute risk reduction of 1.3% for the percentage of patients transferred to hospital (PPTH; relative risk reduction of 53%).
Physicians reported that POCUS improved the diagnosis, management, and disposition of select patients at a remote, multi-day music festival. Also, POCUS reduced ambulance transfers off-site and reduced the perceived burden on broader health care utilization.
PragerR, SedgwickC, LundA, KimD, HoB, StachuraM, GutmanS. Prospective Evaluation of Point-of-Care Ultrasound at a Remote, Multi-Day Music Festival. Prehosp Disaster Med. 2018;33(5):484–489.
Left ventricular outflow tract pseudoaneurysms are a rare but life-threatening disorder, often caused by complications of cardiac surgery or myocardial infarction. We present a case report of a patient with no prior risk factors who presented with a six-month history of progressive exertional dyspnea, bilateral leg swelling and cough. Point-of-care ultrasound revealed an unexpected outpouching of the left ventricle. He was diagnosed with a left ventricular outflow tract pseudoaneurysm and subsequently went into cardiogenic shock secondary to extension of pseudoaneurysm causing extrinsic compression of the coronary arteries. The patient underwent successful emergency surgical repair and made a full recovery.
Diaphragm excursion method is unsuitable for diagnosis of diaphragm paralysis during positive pressure ventilation. We diagnosed diaphragm paralysis in a neonate, without interrupting positive pressure respiratory support after cardiac surgery, using the diaphragm thickness fraction, which could be evaluated during mechanical ventilation and was unaffected by bowel gases. The diaphragm thickness fraction method can help diagnose diaphragm dysfunction using only echography.
The imaging of stones in the salivary glands and ducts poses a challenge, even to experienced ultrasound examiners. This study investigated whether the ‘twinkling artefact’, which occurs at internal calcific foci during Doppler ultrasound examinations, is useful for detecting salivary gland stones.
In a model test, 20 salivary stones were analysed in vitro, via Doppler ultrasound, with regard to their representability and the triggering of the twinkling artefact. In a follow-up study, 28 patients with sialolithiasis and food-related large salivary gland swellings were examined, using both power and colour Doppler modes, with regard to the twinkling artefact. All ultrasound examinations were performed by an experienced examiner and retrospectively graded by two experienced sonographers.
All stones could reliably be detected using the twinkling artefact in the model test. Twenty-seven of 28 salivary stones (96 per cent) also showed twinkling in vivo, during patient assessment. The power Doppler mode showed a significantly higher intensity level of twinkling than the colour Doppler mode (p < 0.0001).
The twinkling artefact is a very reliable sign for the diagnosis of sialolithiasis. Power Doppler is superior to colour Doppler for detection of the twinkling artefact.
Long bone fractures (LBFs) are among the most frequent traumatic injuries seen in emergency departments. Reduction and immobilization is the most common form of treatment for displaced fractures. Point-of-care ultrasound (PoCUS) is a promising technique for diagnosing LBFs and assessing the success of reduction attempts. This article offers a comprehensive review of the use of PoCUS for the diagnosis and reduction of LBFs.
MEDLINE and EMBASE databases were searched through July 19, 2015.
We included prospective studies that assessed test characteristics of PoCUS in 1) the diagnosis or 2) the reduction of LBFs. The methodological quality of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.
Thirty studies met inclusion criteria (n=3,506; overall fracture rate 48.0%). Test characteristics of PoCUS for the diagnosis of LBFs were as follows: sensitivity 64.7%–100%, specificity 79.2%–100%, positive likelihood ratio (LR) 3.11–infinity, and negative LR zero–0.45. Sensitivity and specificity for the adequate reduction of LBFs with PoCUS were 94%–100% and 56%–100%, respectively. PoCUS diagnosis of pediatric forearm fractures in 10 studies showed a pooled sensitivity of 93.1% (95% confidence interval [CI], 87.2%–96.4%) and specificity of 92.9% (95% CI, 86.6%–96.4%), and PoCUS diagnosis of adult ankle fractures in four studies showed a pooled sensitivity of 89.5% (95% CI, 77.0%–95.6%) and specificity of 94.2% (95% CI, 86.1%–97.7%).
PoCUS demonstrates good diagnostic accuracy in all LBFs studied, especially in pooled results of diagnosis of pediatric forearm and adult ankle fractures. PoCUS is an appropriate adjunct to plain radiographs for LBFs.
Recent studies have suggested an association between vitamin D and non-alcoholic fatty liver disease (NAFLD); however, some results are subject to debate. This study was carried out to evaluate the correlation between NAFLD and vitamin D in men and women in East China. The data were obtained from a cross-sectional study that focused on the health and metabolic status of adults in sixteen areas of East China. According to ultrasonic assessments, the patients were divided into normal and NAFLD groups. Demographic characteristics and biochemical measurements were obtained. Binary logistic regression analysis was used to explore the association. In total, 5066 subjects were enrolled, and 2193 (43·3 %) were diagnosed with NAFLD; 84·56 % of the subjects showed vitamin D deficiency. Subjects with high vitamin D levels had a lower prevalence of NAFLD, particularly male subjects. Within the highest quartile of vitamin D levels, the prevalence of NAFLD was 40·8 %, whereas the lowest quartile of vitamin D levels showed a prevalence of 62·2 %, which was unchanged in women across the vitamin D levels. Binary logistic analysis showed that decreased vitamin D levels were associated with an increased risk of NAFLD (OR 1·54; 95 % CI 1·26, 1·88). This study suggests that vitamin D levels are significantly associated with NAFLD and that vitamin D acts as an independent factor for NAFLD prevalence, particularly in males in East China. Vitamin D interventional treatment might be a new target for controlling NAFLD; elucidating the mechanism requires further research.
Very few effective field methods are available for accurate, non-invasive estimation of skeletal muscle volume (SMV) and mass in children. We aimed to develop regression-based prediction equations for SMV, using ultrasonography, in Japanese prepubertal children, and to assess the validity of these equations. In total, 145 healthy Japanese prepubertal children aged 6–12 years were randomly divided into two groups: the model development group (sixty boys, thirty-seven girls) and the validation group (twenty-nine boys, nineteen girls). Reference data in the form of contiguous MRI with 1-cm slice thickness were obtained from the first cervical vertebra to the ankle joints. The SMV was calculated by the summation of digitised cross-sectional areas. Muscle thickness was measured using B-mode ultrasonography at nine sites in different regions. In the model development group, strong, statistically significant correlations were observed between the site-matched SMV (total, arms, trunk, thigh and lower legs) measured by MRI and the muscle thickness×height measures obtained by ultrasonography, for both boys and girls. When these SMV prediction equations were applied to the validation groups, the measured total and regional SMV were also very similar to the values predicted for boys and girls, respectively. With the exception of the trunk region in girls, the Bland–Altman analysis for the validation group did not indicate any bias for either boys or girls. These results suggest that ultrasonography-derived prediction equations for boys and girls are useful for the estimation of total and regional SMV.
Bilateral retinal detachments are a rare complication of preeclampsia. We present a case report of a patient with an unknown pregnancy who presented with acute bilateral vision loss and elevated blood pressure. Point-of-care ocular ultrasound revealed bilateral retinal detachments. She was diagnosed with severe preeclampsia and taken for an urgent caesarean section with the delivery of a 26-week-old infant.
This study aimed to investigate the prevalence and clinical significance of solitary thyroid nodules in patients who underwent thyroid surgery.
A retrospective review was performed of the case notes of all adult patients who underwent thyroid surgery from January 2003 to December 2009. All patients with solitary thyroid nodules identified by ultrasonography were included.
In total, 225 patients underwent thyroid surgery. The prevalence of solitary thyroid nodules was 27.1 per cent (61 out of 225 patients). Seventy-two per cent of patients were women and the mean age at presentation was 52 ± 16 years. In all, 75.4 per cent of solitary nodules had neoplastic pathology and the malignancy rate was 34.4 per cent. The sensitivity and specificity of fine needle aspiration cytology for neoplasm detection were 73.9 per cent and 80.0 per cent, respectively. There was no association between the various ultrasonography parameters and malignancy risk (p > 0.05).
Solitary thyroid nodules should be investigated thoroughly with a high index of suspicion because there is a high probability (34.0 per cent) of malignancy.
Objective of the study was to record, by means of ultrasonographic examination, changes occurring during lactogenesis in the udder of healthy ewes and of ewes with pregnancy toxaemia. The work was carried out in 28 ewes, 16 with pregnancy toxaemia (group A) and 12 healthy controls (group B). B-mode and Doppler ultrasonographic examination of the udder of ewes was performed. During the last month of pregnancy, grey-scale intensity values of mammary parenchyma in group A were significantly greater than in group B (P = 0·007), as was also the progressive increase in grey-scale intensity values in both groups (P < 0·001). Blood mammary input was significantly greater in ewes of group B than in ewes of group A (P < 0·05), as was also the progressive increase in blood input in both groups (P < 0·001). Further, differences between the two groups were identified in pulsatility index (P = 0·007) and in mean blood velocity (P = 0·036), but only during the last fortnight of pregnancy. After lambing, grey-scale values decreased sharply compared to those in pregnancy (P < 0·01), whilst blood input, pulsatility index and mean blood velocity continued the same trend as at the last stage of pregnancy, with differences between the two groups still prevalent (P < 0·05). There was a reverse correlation between grey-scale intensity values and milk quantities (P < 0·035) and a correlation between blood input and milk quantities (P < 0·07). The progressive increase in the diameter of the external pudendal artery was significant (P < 0·001), but no significant differences were evident between the two groups (P > 0·35). Differences between group A and group B in all other haemodynamic parameters studied were not significant, neither throughout the last month of pregnancy (P > 0·25), nor during the first week of lactation (P > 0·06). However, their progressive changes during the last month of pregnancy were significant (P < 0·02).
Determining which patients with ureterolithiasis are likely to require urologic intervention is a common challenge in the emergency department (ED). The objective was to determine if normal renal sonogram could identify low-risk renal colic patients, who were defined as not requiring urologic intervention within 90 days of their initial ED visit and can be managed conservatively.
This was a prospective cohort study involving adult patients presenting to the EDs of a tertiary care centre with suspected renal colic over a 20-month period. Renal ultrasonography (US) was performed in the diagnostic imaging department by trained ultrasonographers, and the results were categorized into four mutually exclusive groups: normal, suggestive of ureterolithiasis, visualized ureteric stone, or findings unrelated to urolithiasis. Electronic medical records were reviewed to determine if patients received urologic intervention within 90 days of their ED visit.
Of 610 patients enrolled, 341 (55.9%) had US for suspected renal colic. Of those, 105 (30.8%) were classified as normal; none of these patients underwent urologic intervention within 90 days of their ED visit. Ninety (26.4%) US results were classified as suggestive, and nine (10%) patients received urologic intervention. A total of 139 (40.8%) US results were classified as visualized ureteric stone, and 34 (24.5%) patients had urologic intervention. Seven (2.1%) US results were classified as findings unrelated to urolithiasis, and none of these patients required urologic intervention. The rate of urologic intervention was significantly lower in those with normal US results (p<0.001) than in those with abnormal findings.
A normal renal sonogram predicts a low likelihood for urologic intervention within 90 days for adult ED patients with suspected renal colic.