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Thứ Sáu, 28 tháng 9, 2012

SIÊU ÂM trong ICU

 
 
Discussion
Our study is unique in that it is a surveillance study of 125 consecutive patients whose evaluation entailed a global assessment encompassing clinical and ultrasound examination. Unlike previous works,2–6 it was performed to evaluate a protocol for head-to-toe ultrasound examination performed by a team of ICU physicians experienced in ultrasonography. Real-time ultrasound evaluation (within 12 h of admission) was done by the attending physician. The approach is based on the assumption that intensive care physicians with enough expertise can interpret sonographic images. Ultrasound training is not mandatory for ICU physicians in Italy, although proposals for graded competence have been advanced. Since 2000, the Society for Academic Emergency Medicine guidelines for physician training in emergency ultrasonography12 have informed the continuing medical education program of our ICU physicians. During their time in the course, physicians are required to perform 150 practice sections, including 60 heart, 10 chest, 60 abdomen, and 20 peripheral vein ultrasound examinations. After the course, the physicians receive 1 yr of tutored instruction. Drawn up in 2008, the ICU-sound protocol was tested for 6 months before entering daily clinical practice. Our data suggest that the protocol is not excessively time-consuming: a mean duration of 19.5 min to complete the scan is acceptable considering the protocol's complexity. Patient- and environment-related ultrasonography limitations had little influence on the majority of the ultrasound examinations in this study.
We used optic nerve sonography as an additional noninvasive diagnostic tool to detect increased intracranial pressure preceding emergency computed tomography or the decision to start invasive monitoring of intracranial pressure. Ultrasound examination revealed new findings of optic nerve sheath enlargement in six cases, in all of which computed tomography showed unknown intracranial hypertension, demonstrating the importance of this easy-to-perform ultrasound evaluation at admittance to a general ICU.
 
 
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Two cases of unknown deep venous thrombosis were identified, one an internal jugular vein thrombosis (fig. 1). Upper extremity venous thrombosis is thought to be quite rare, but a recent report found that 18% of all cases involve upper extremity thrombi. Patients in the ICU setting are especially vulnerable to developing upper extremity thrombosis, and the clinical symptoms associated with an upper-extremity clot are frequently absent because of the extensive collateral network. A combined strategy using echocardiography and venous ultrasonography is a reliable method for diagnosing pulmonary embolism at the bedside.
 
Pleural effusion is often encountered in ICU patients; the diagnosis relies mostly on an anteroposterior chest radiograph obtained at the bedside. Pleural ultrasonography, an alternative imaging modality, has been validated against chest computed tomography, the accepted reference for diagnostic methods to identify pleural disease. The prevalence of significant pleural effusions in a medical ICU varies widely from 8.4 to 62%. In our study, effusions (small effusions less than 200 ml were not considered) were found in 35/125 patients (28%), 20 (57.1%) of whom underwent drainage and thoracenthesis. The estimated drainage volume was obtained using the formula proposed by Balik et al. It has been recently shown, however, that this formula can underestimate the volume, whereas a multiplane approach can increase the accuracy of quantifying small and moderate pleural effusion. Although more time-consuming (10 min), an accurate evaluation of effusion volume is a critical element in deciding whether to perform thoracenthesis. And it becomes even more relevant when weaning is considered, because drainage may reduce the work of breathing and increase respiratory muscle efficiency. The decision to drain was based on our clinical practice (reduced chest wall compliance, difficult weaning, refractory hypodynamic circulatory states) or when ultrasound suggested an infectious effusion (homogeneous echogenicity, septation, fibrin strands, nodular pleural changes). Pleural effusion can cause dissociation between effective preload and cardiac filling pressures. Drainage may be effective in patients with refractory hypodynamic circulatory states, particularly when there is evidence for diastolic chamber collapse.
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Ultrasound examination was effective in evidencing the presence of anterior pneumothorax not detected by supine anteroposterior chest radiography (three cases). This finding holds clinical relevance, because during positive pressure ventilation a small pneumothorax may progress and cause hemodynamic instability. Ultrasound has proved to be more sensitive than anteroposterior chest radiography in the diagnosis of pneumothorax and can decrease the need for computed tomography for the diagnosis of occult pneumothorax. Lower lobe parenchymal consolidation without air bronchogram visualization can be difficult to distinguish from pleural effusion on an anteroposterior chest radiograph. Ultrasonography showing consolidation (with or without pleural effusion) can help in avoiding a possible mistake because of a misread chest radiograph (fig. 2).
 
 
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Lung sonography is a useful aid in differentiating cardiogenic respiratory failure from acute airflow limitation, consolidation, pleural effusion, or pulmonary embolism. In our study, the diagnostic efficacy of lung ultrasound to differentiate dyspneic patients is well represented. Lung ultrasound pointed out 55 new findings, enabling us to differentiate the etiologic diagnosis in patients with a generic admitting diagnosis of acute respiratory insufficiency. Combining the data from lung sonography and echocardiography can enhance the diagnostic accuracy in differentiating respiratory insufficiency (fig. 3).
 
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In a previous study, transthoracic echocardiography performed by intensivists provided new information and changed management in 37% of critical patients and added useful information to an additional 47% of patients, but did not alter immediate treatment. In our study, echocardiography revealed 53 new findings, leading to changes in therapy in 11/125 patients. These data confirm the importance of transthoracic echocardiography in ICU patients.
 
Abdominal examination evidenced 20 new pathologic findings and induced changes in therapy in 3/125 cases. The presence of the classic signs of acute acalculous cholecystitis at ultrasound examination, together with clinical data, enabled us to identify the origin of sepsis of unknown etiology (fig. 4). In our study, new ultrasound abnormalities were most often detected in patients with septic shock, followed by those with acute cardiac decompensation. This is not surprising, as these patients have multiple organ failure. ICU mortality was higher, but not statistically significant, in patients with two or more pathologic findings compared with patients without any findings. Mortality generally depends on the specific type of the most life-threatening abnormality, along with many other factors unrelated to ultrasound findings. Of note is that patients with no ultrasonographic pathologic findings had a better prognosis.
 
We plan to extend the ICU-sound protocol to include other diagnostic tools: transcranial Doppler and positive end-expiratory pressure-induced lung recruitment. Recent reports have shown, in fact, that lung reaeration can be assessed by ultrasound. It is rapid and repeatable at the bedside, does not require sedation and paralysis, and can be used to analyze dependent and not-dependent lung regions. Patients with acute lung injury, the adult respiratory distress syndrome, and pulmonary edema may benefit from ultrasound monitoring of positive end-expiratory pressure-induced reaeration; however, a limitation is that lung hyperinflation cannot be assessed.
 
Study Limitations
 
There is a potential for bias, as the operators in this study were not blinded to the patient's clinical picture, which is difficult to entirely eliminate in any use of ultrasound. The study relied only on transthoracic echocardiography; therefore, the true prevalence of cardiac ultrasound abnormalities may have been underestimated. Also, the prevalence of pleural effusion may have been underestimated with the use of a formula, which has been shown inadequate to quantify small and moderate effusions. An evaluation of the usefulness of a head-to-toe versus a focused examination was beyond the scope of this study. The major finding of this study is the discovery of a high prevalence of unsuspected clinical abnormalities in ICU patients. Ultrasound examination permitted us to modify the diagnosis and to improve the treatment, with prompt changes in therapeutic strategy. Patient- and environment-related sonography limitations had little influence on the majority of the examinations. The test can be performed by the attending ICU physician, with minimal risk of overuse or misinterpretation. Moreover, ultrasound use in the ICU could be optimized by making ultrasonography a routine part of intensive care training during residency. In experienced hands, rapid global assessment of critical patients at ICU admittance under this ultrasound protocol holds potential for improving healthcare quality.
 
 

Thứ Năm, 27 tháng 9, 2012

M-mode SONOGRAPHY and FETAL ARRHYTHMIAS


o        © 2012 by the American Institute of Ultrasound in Medicine

SIÊU ÂM ĐIỀU TRỊ VIÊM GÂN VÔI HOÁ CHÓP XOAY


Sonographically Guided Lavage Aspiration Technique
 

The patient is positioned such that the calcification to be treated is well visualized and amenable to needle placement and that both the patient and physician will be comfortable throughout the procedure. Depending on the

calcification location, particularly within the supraspinatus tendon and deep to the overlying acromion process of the scapula, it may be necessary to experiment with various armpositions of the patient to achieve this goal. Generally, the procedure is performed with the patient in the lateral decubitus or supine position for supraspinatus and infraspinatus calcification and in the supine position if the subscapularis tendon is the target.

 

A high-resolution linear probe (10–17 MHz) is used for this procedure, as the target calcification is usually very superficial. A 25-gauge needle is used for local anesthesia, and a 16- to 18-gauge needle is generally used for the lavage aspiration. Although some authors have advocated a smaller needle size (22 gauge), 20 in this author’s experience, a larger needle allows a faster andmore complete evacuation of calcium. Although others also advocate a 2-needle approach, and excellent results have been achieved with this method, this author has not found that approach to substantially improve calcium removal or to decrease the procedure time.
 
A recent study of 462 patients suggests that warming the lavage fluid may help improve dissolution of calcium and shorten the procedure time, which may prove to further optimize this technique.

However, this large study did not show a significant difference in patient outcomes as determined by visual analog scale scores between the two groups.

In preparation for the lavage aspiration, a series of syringes are prepared (3–6, depending on the size of the calcification) containing a mixture of saline and an anesthetic. This author favors a blend of 70% sterile saline and 30% lidocaine, 1%. A syringe containing an additional anesthetic (0.25% bupivacaine HCl) and cortisone (triamcinolone acetonide or methylprednisolone acetate) is also prepared for the subacromial-subdeltoid bursal injection that concludes the procedure, with the bupivacaine providing relief of postprocedure discomfort for several hours.

Continuous sonographic visualization of the calcification and needle is necessary throughout the procedure.

A liberal amount of anesthetic is administered subcutaneously, within the deeper soft tissues and within the subacromial-subdeltoid bursa, being sure that no air is introduced into the soft tissues or adjacent subacromial-subdeltoid bursa, extending from the skin entry site to themargin of the calcification along the expected path of lavage needle placement. If air is injected and is superficial to the target calcification, particularly within the subacromial-subdeltoid bursa, the calcification may be entirely obscured, and the proceduremay need to be postponed until the air is resorbed, which may take several days. With appropriate local anesthetic administration, the procedure is generally well tolerated with only mild discomfort. With continuous sonographic visualization, the 16- or 18-gauge needle is advanced into the epicenter of the calcific focus with a single puncture (Figure 3). Using the syringes filled with the anesthetic/saline  mixture noted above, intermittent plunger pressure and release are performed until a cavity forms within the focus of calcification (Figure 4). At this point, swirling of echogenic material (calcium) will be seen within the cavity, and with plunger release, this calcific material will decompress into the syringe. If more than a single puncture is made into the lesion, the lavage material may decompress through this additional hole in the calcific focus, and the yield of calcium removed will be diminished.
 

As large amounts of calcium fill the syringe, exchange is made for new clear syringes until no further calcification may be removed. The calcific material removed will be seen to layer within the dependent portion of the syringe (Figure 5). At this point in the procedure, any remaining calcification along the wall of the original focus is fenestrated using the needle. If additional foci of calcification are present, these are treated in the same manner. At the conclusion of this process, any remaining calcium fragments too small for lavage are also fenestrated with the needle. Finally, the mixture of anesthetic and corticosteroid described above is injected into the adjacent subacromial-subdeltoid bursa, which will provide considerable pain relief over the next several weeks to months as additional calcific material decompresses into the bursa from the involved rotator cuff tendon.
 
 
 

Although follow-up radiographs are not routinely obtained, they may show a rapid and marked decrease in the amount of calcification remaining within the tendon. In patients with recurrent or residual pain after therapy, subsequent sonographic examinations may be performed to assess the degree of calcification within the tendon or subacromial-subdeltoid bursa. Patients in this group may often be effectively treated with a sonographically guided bursal cortisone and anesthetic injection.

 

Conclusions

Calcific tendinosis of the rotator cuff is a commonly diagnosed entity that is responsible for a great deal of patient pain and limitation of mobility. Although radiographs remain the mainstay of initial calcium visualization and diagnosis, sonography can localize the calcification to the specific tendon involved, assess the entire rotator cuff for tears or tendinosis, and also evaluate the adjacent biceps tendon and subacromial-subdeltoid bursa for concomitant abnormalities. Finally, diagnostic sonography provides the means by which this condition can be safely treated by the percutaneous technique described above. This technique quickly removes and fragments the problematic calcification with a low incidence of complications, and multiple studies have shown an excellent clinical response in most patients. Lavage aspiration with sonographic guidance has thus become the optimal modality for effective treatment of this painful condition.

Thứ Hai, 24 tháng 9, 2012

NHÂN CA VỠ TÁ TRÀNG tại MEDIC: VAI TRÒ CHẨN ĐOÁN và THEO DÕI của SIÊU ÂM


A traumatic duodenal hematoma (DH) is an unusual event, occurring mainly in children and young individuals, with a male predominance in both age groups. Furthermore, it can be a diagnostic challenge because of unreliable history, nonspecific signs and symptoms, delayed appearance, and the duodenum’s retroperitoneal location.1,2
Sonography is considered a reliable screening tool for blunt abdominal trauma (BAT)3,4; however, since the beginning of the last decade, only a small number of reported DH cases5–,8 have been described by sonography.

Discussion

Accurate diagnosis is essential for proper treatment of a DH. The clinical appearance and findings including abdominal pain, vomiting, tenderness, and a palpable mass can be nonspecific, accompanied by unremarkable laboratory test results.6,8
Blunt abdominal trauma, sometimes minor, is the leading cause of DHs, which occur in approximately four fifths of patients.9,10 Bleeding disorders, Henoch-Schönlein purpura, anticoagulation therapy, alcoholism, pancreatitis, tumors, duodenal ulcers, and local or iatrogenic factors are other implicative causes.7,10–,13

Most hematomas resolve spontaneously without permanent changes. Treatment may be surgical or conservative using nasogastric suction and adequate parenteral nutrition. Expectant treatment of an isolated DH is generally preferred. Failure of conservative treatment is considered when there is no evidence of partial resolution after 5 days or complete resolution after 10 days or in cases of perforation, indicating surgical treatment.14

All pictures extracted from http://cai.md.chula.ac.th/lesson/atlas/T/page1t.html
 

An upper GI series was for many years the only diagnostic tool for DHs before the advent of CT, which has been established as the examination of choice for duodenal injuries, especially in disclosing complications such as perforation and abscesses.15 However, CT was found to be diagnostic in 60% of patients with duodenal perforation.1

 
 

Various sonographic patterns have been described in DHs: (1) a duodenal wall thickening with hypoechogenicity16; (2) a duodenum-related mass of variable echogenicity, depending on the age of the hematoma7; and (3) a prevertebral cystic lesion simulating a pancreatic pseudocyst.6 This variability may reflect the difficulty in distinguishing the origin of small retroperitoneal lesions proximal to the bowel wall in the upper abdomen because of the enteric gas component and also the different characteristics of a hematoma depending on its age. Color-coded imaging has been shown to be helpful in differentiating a spontaneous DH from an intestinal mass.8
Sonography may be the first examination performed in a patient with epigastric abdominal pain or a palpable abdominal mass,8 and it is useful to be familiar with this uncommon entity. In BAT, sonography can additionally show associated lesions, including pancreatic traumatic pseudocysts and parenchymal lacerations, or a small amount of ascites caused by peritoneal blood or pancreatic fluid.17

In conclusion, sonography may play a primary role, both in the diagnosis and the monitoring of DHs, when conservative treatment is attempted. Computed tomography may be reserved for inconclusive cases.

*          © 2004 by the American Institute of Ultrasound in Medicine

Thứ Sáu, 21 tháng 9, 2012

NHÂN CA BUDD-CHIARI SYNDROME tại MEDIC

BUDD-CHIARI SYNDROME [BCS]

@ MEDIC:
Female patient 25yo from Vinh long province had been diagnosed hepatosplenomegaly with unknown cause from 2004 in many hospitals. Ultrasound detected IVC underdiaphramatic stenosis, big caudate lobe and big spleen and liver with coase pattern due to regenerative nodules. 
MDCT 64 disclosed a web into IVC and collateral circulations and hepatosplenomegaly. So it was a case of  BUDD-CHIARI Syndrome due to MOVC (membraneous obtruction of inferior vena cava). The female patient remains well after an bridging operation to connect subrenal IVC to right subclavian vein.
 
 
@ BUDD-CHIARI SYNDROME [BCS]: ULTRASOUND
 

An enlarged caudate lobe, hepatomegaly, lack of visualization of the hepatic veins, a compressed IVC, enlarged intrahepatic collaterals, splenomegaly, and ascites are conventional sonographic findings in patients with BCS. In some instances, an enlarged caudate lobe vein ( > 3 mm) can be seen draining directly into the IVC, a spider-web appearance of hepatic veins or replacement of the hepatic vein by a fibrous, echogenic cord. Ultrasound may also show that the stenotic IVC, especially in the intrahepatic segment, is associated with an enlarged caudate lobe. In some chronic cases, large regenerative nodules that may simulate carcinoma may be present. On Doppler evaluation, patients with BCS may present with enlarged hepatic veins with no flow signal or with reversed flow. The identifcation of collateral vessels with drainage into the subcapsular or intercostal veins is a highly sensitive and specifc feature for the diagnosis of BCS.

See CDUS in Budd-Chiari Syndrome
và   SIÊU ÂM BUDD-CHIARI SYNDROME

Thứ Năm, 20 tháng 9, 2012

TẮC LỆ ĐẠO Ở THAI NHI

BS JASMINE THANH XUÂN
Khoa Siêu âm Medic TPHCM.

- Thuật ngữ : Dacryocystocele: tắc lệ đạo.
- Lệ đạo là hệ thống đường dẫn nước mắt đi từ vùng hồ lệ đến khe mũi dưới, bao gồm: điểm lệ, lệ quản, túi lệ, ống lệ mũi. Bình thường, nước mắt được tiết ra từ các tuyến lệ, sau khi đã làm ướt bề mặt nhãn cầu, phần còn lại sẽ đổ vào điểm lệ, vào lệ quản, túi lệ, qua ống lệ mũi và đổ ra ngách mũi phía dưới. Khi có bệnh lý ở đường lệ, nước mắt sẽ bị ứ đọng và gây chảy nước mắt, đôi khi kèm theo mủ và nhầy.
- Lệ đạo ở thai nhi vốn là một ống đặc, chỉ trở nên rỗng ở những tháng cuối. Khi sinh ra, đa số trẻ có lệ đạo đã thông suốt để thực hiện chức năng dẫn lưu nước mắt; nhưng ở một số trẻ, quá trình tạo ống vẫn tiếp tục sau đó 1-2 tuần.
Tuyến lệ bình thường và hình Tắc lệ đạo (sơ đồ). Nguồn : Visual Art @ 2007. The University of Texas. M.D. Anderson Cancer Center.

- Tắc lệ đạo có thể phát hiện được trong thời kỳ mang thai bằng siêu âm khảo sát vùng quanh nhãn cầu.
- Khảo sát hình thái học thai nhi ở 3 tháng giữa cần thiết phải cắt ngang qua hai nhãn cầu, cho phép đánh giá nhãn cầu xa nhau, gần nhau… gợi ý các bất thường về nhiễm sắc thể.
- Chiều dài đường nối liền hai thuỷ tinh thể (tính bằng đơn vị mm) sẽ tương ứng với tuổi thai tính theo tuần.
- Ví dụ : Thai nhi 22 tuần , đường nối ngang tâm hai thuỷ tinh thể sẽ tương ứng 22mm.
- Một số máy siêu âm chuyên về khảo sát thai sẽ cho biết tuổi thai nhi (tính bằng tuần) khi đo đường kính bờ ngoài hai hốc mắt (OOD = Outer Orbicular Diameter).

Minh hoạ : tuổi thai 22 tuần 1 ngày được tính bằng cách đo OOD.

 
Hình minh hoạ : đường cắt khảo sát quanh hốc mắt phải thai nhi, cho thấy một cấu trúc dạng nang echo trống giống nhãn cầu nhưng kích thước nhỏ hơn, gợi ý túi dịch ( túi lệ) trong tắc lệ đạo thai nhi.
Hình tái tạo 3D: trên thai nhi này cho thấy rõ nét dưới khoé mắt phải có cấu trúc giống hình giọt nước mắt lớn (gợi ý tắc túi lệ thai nhi).

- Thai nhi được khảo sát sau đó 6 tuần, không còn thấy hình ảnh túi echo trống nằm sát dưới nhãn cầu phải nữa. Điều này cho thấy lệ đạo thai nhi là một ống đặc, và rỗng ở những tháng cuối. Do đó nước mắt đã được lưu thông xuống ngách mũi dưới.


Hình minh hoạ một trường hợp khác cho thấy sau sanh có hình ảnh tắc lệ đạo bên Trái.
Nguồn : Internet.
- Tóm lại , tắc lệ đạo bẩm sinh có thể phát hiện từ trong thời kỳ bào thai bằng cách siêu âm khảo sát kỹ hai nhãn cầu. Đường cắt ngang hai nhãn cầu để tính tuổi thai cho thấy cấu trúc dạng nang echo trống sát dưới nhãn cầu gợi ý có tắc lệ đạo. Tắc có thể thoáng qua ở những tháng đầu thai kỳ, sau đó sẽ tự biến mất, hoặc kéo dài đến sau sanh 1- 2 tuần hay nhiều tháng sau sanh.