Feasibility of Combined Doppler-ECG Assessment of Internal Jugular Veins.

A standardized combined Doppler-electrocardiography technique was developed for measurement of the triphasic waveform characteristics in the internal jugular vein. Flow velocities at the A, X, V and Y peaks, the RR interval and the PA and RX times were measured. From these the venous impedance index ([X-A]/X) and the ratios PA/RR and RX/RR were calculated. Six measurements were performed at three different locations by two ultrasonographers in 21 randomly selected pregnant and non-pregnant women. Statistical models proved the feasibility and reproducibility of this technique, with the highest concordance correlation coefficients in the right distal internal vein. Bootstrapping revealed that repeating the measurements more than four times would not significantly enhance the precision of the estimated mean. Concordance correlation coefficients for the venous impedance index, PA time and PA/RR ratio were >0.63 for all three locations, proving their possible use in ongoing and future studies, analogous to previous studies in kidney and liver.

Diagnosis of pheochromocytoma in a hemodialysis patient through measurement of plasma catecholamines.

We report the case of a patient on chronic hemodialysis treatment with paroxysms of severe arterial hypertension accompanied by tachycardia, pallor, sweating and tremor. Measurement of plasma catecholamines revealed norepinephrine level of 4625 pg/mL (reference range 191-225 pg/mL), epinephrine level of 1035 pg/mL (58-76 pg/mL) and dopamine level of 148 pg/mL (50-100 pg/mL). MRI showed a left adrenal mass of 2 cm. After the patient was started on an alpha-1 adrenergic receptor blocker, she underwent a left adrenalectomy. Anatomopathological examination confirmed the diagnosis of pheochromocytoma. Although urinary testing is not possible in anuric hemodialysis patients, diagnosis of pheochromocytoma can be made through measurement of plasma free metanephrines and/or plasma catecholamines.

Ten good reasons to practice ultrasound in critical care.

Over the past decade, critical care ultrasound has gained its place in the armamentarium of monitoring tools. A greater understanding of lung, abdominal, and vascular ultrasound plus easier access to portable machines have revolutionised the bedside assessment of our ICU patients. Because ultrasound is not only a diagnostic test, but can also be seen as a component of the physical exam, it has the potential to become the stethoscope of the 21st century. Critical care ultrasound is a combination of simple protocols, with lung ultrasound being a basic application, allowing assessment of urgent diagnoses in combination with therapeutic decisions. The LUCI (Lung Ultrasound in the Critically Ill) consists of the identification of ten signs: the bat sign (pleural line); lung sliding (seashore sign); the A-lines (horizontal artefact); the quad sign and sinusoid sign indicating pleural effusion; the fractal and tissue-like sign indicating lung consolidation; the B-lines and lung rockets indicating interstitial syndromes; abolished lung sliding with the stratosphere sign suggesting pneumothorax; and the lung point indicating pneumothorax. Two more signs, the lung pulse and the dynamic air bronchogram, are used to distinguish atelectasis from pneumonia. The BLUE protocol (Bedside Lung Ultrasound in Emergency) is a fast protocol (< 3 minutes), also including a vascular (venous) analysis allowing differential diagnosis in patients with acute respiratory failure. With this protocol, it becomes possible to differentiate between pulmonary oedema, pulmonary embolism, pneumonia, chronic obstructive pulmonary disease, asthma, and pneumothorax, each showing specific ultrasound patterns and profiles. The FALLS protocol (Fluid Administration Limited by Lung Sonography) adapts the BLUE protocol to be used in patients with acute circulatory failure. It makes a sequential search for obstructive, cardiogenic, hypovolemic, and distributive shock using simple real-time echocardiography in combination with lung ultrasound, with the appearance of B-lines considered to be the endpoint for fluid therapy. An advantage of lung ultrasound is that the patient is not exposed to radiation, and so the LUCI-FLR project (LUCI favouring limitation of radiation) can be unfolded in trauma patients. Although it has been practiced for 25 years, critical care ultrasound is a relatively young but expanding discipline and can be seen as the stethoscope of the modern intensivist. In this review, the usefulness and advantages of ultrasound in the critical care setting are discussed in ten points. The emphasis is on a holistic approach, with a central role for lung ultrasound.

Long-term arterial adaptation to high blood flow in the feeding artery of vascular access for hemodialysis.

PURPOSE: Arteries continuously respond to changing tissue demands and to hemodynamic conditions by altering their diameter and wall structure. The relatively slow dilatation of the feeding artery of vascular accesses continues at least two years after access creation with a continuous decrease in wall shear rate (WSR), which however, remains highly supra-physiological. The aim of this study was to test the hypothesis that after a longer time period the WSR returns to its baseline value. METHODS: In a cross-sectional study patients with arteriovenous fistulae were classified into four groups according to the access vintage (from new access to accesses older than six years). The WSR, cross-sectional area, and mean circumferential wall stress were measured and compared between groups. RESULTS: WSR decreased from group 1 (fistula < ninety days old) to group 4 (fistulae > six years old) with a concomitant increase in internal diameter. Patients with the oldest access had normal WSR values (compared to the contralateral brachial artery) and the largest internal diameter of the feeding artery. In diabetic patients the absolute values of WSR were higher and internal diameter was lower compared to nondiabetic patients. CONCLUSIONS: Brachial artery WSR is normal in accesses older than six years with an increased internal diameter and wall cross-sectional area as compared to "younger" accesses. This suggests a process of vascular remodeling with an increase in vascular wall mass and normalization of WSR to physiologic values at the price of increased mean cross-sectional wall stress.

Establishing the learning curve for a tunneled dialysis catheter placement.

PURPOSE: To determine how many procedures a surgical trainee requires before they are able to place a tunneled double-lumen dialysis catheter safely on their own. METHODS: Surgical trainees unfamiliar with the procedure received a pre-operative briefing in which we explained 1) why, how, and in what particular order each operational step should be executed and 2) what the possible pitfalls/complications are. Next, an experienced surgeon demonstrated the procedure with the trainee scrubbed-in as their assistant. The trainee then performed all successive procedures, while the supervising surgeon acted as a silent observer and intervened only when an error was made. We recorded all errors as well as near misses and noted if they were severe, recurrent or unanticipated. At least three procedures were required but training was continued until less than three errors were made. RESULTS: Ten trainees were included in the study. On average, a trainee made 11.9 mistakes during 3.4 procedures in a time span of 28.2 days. Only three trainees performed their last procedure flawlessly. The number of errors decreased exponentially from the first procedure onwards (P<.001). A statistically significant correlation was found between the number of mistakes and the number of days since the last procedure (P<.035). Unanticipated errors most frequently involved erroneous fluoroscopy interpretation, flushing with blood-contaminated saline, and incorrect volume injection for the heparin lock. CONCLUSIONS: A theoretically well-prepared surgical trainee should be able to perform the placement of a tunneled dialysis catheter safely after four procedures. Training is more efficient when procedures follow each other quickly.

Hemodialysis vascular access ultrasonography: tips, tricks, pitfalls and a quiz.

Duplex ultrasonography (DU) is a useful tool to optimize vascular access care in hemodialysis patients. However, the professional training of most healthcare workers caring for dialysis patients does not routinely include the teaching of DU (in this setting), thus limiting its use. The aim of this article is to provide some practical tips, tricks and potential pitfalls of this technique, both to the trainee ultrasonographer and to the healthcare worker already applying this technique in practice. The topics covered are 1) basic ultrasound principles (physics, machines and transducers), 2) the modes needed in vascular access DU in combination with the respective ways to optimize image quality, and 3) the assessment of access flow, stenosis and access induced ischemia by ultrasonography. This is done in the format of a quiz with 12 questions and answers.

Burkholderia pseudomallei sepsis presenting with pericardial effusion and tamponade.

Severe septicaemia secondary to melioidosis carries a high mortality. Although melioidosis can involve most tissues and organs, pericardial involvement is rare. We report a 40-yearold woman with melioidosis with pericardial involvement but no contiguous pulmonary involvement. She developed acute pericardial tamponade but was successfully treated with surgery and medical therapy. This is the first case in Australia or New Zealand of melioid sepsis presenting with pericarditis and subsequent cardiac tamponade. We review the literature on cardiac involvement in melioidosis.