The differential for hyperdynamic LV function is broad, including deranged metabolic states, infectious states, inflammatory states, and hypovolemia. Liberally providing IV fluids for hyperdynamic hearts may not correct some of these states and may drive iatrogenic volume overload which can carry a range of complications including lung injury, impaired mobility, and organ dysfunction. Combining the clinical picture, IVC status and lung profile should be combined with determination of hyperdynamic LV function to facilitate decision-making with regards to IV fluids and beyond.
Other than cardiogenic pulmonary edema, bilateral B-line pattern can be compatible with pneumonia, ARDS, interstitial lung disease and other conditions. Assessments of the pleural line, pulmonary parenchyma (including presence or absence of C-pattern), distribution of B-lines, cardiac status, and – of course – clinical status can help narrow down the etiology.
While more challenging to acquire accurately, cardiac output calculations incorporating LVOT diameter, HR, and LVOT VTI assessments take out complicating factors such as mitral regurgitation which can skew LVEF.
Other lung ultrasound findings, such as absence of A-lines, hepatization, and ill-defined margins are some of the other of findings that can help support a diagnosis of pneumonia over atelectasis.
Other signs are supportive as well, such as plankton sign (swirling debris in the pleural fluid that appear with respiratory motion). As well, complicated fluid may not always be anechoic but can be hyperechoic as well. Another useful finding is the hematocrit sign (demonstrating settling of fluid with increased echogenicity at the dependent area of the effusion where coagulated cells and other debris gather as a result of gravity)
Slowing down the video clip during image interpretation can reveal underlying sluggish hearts. When slowing down the video clip, subjective assessments in addition to endocardial wall excursion, endocardial thickening and EPSS should be applied.
Based on the natural axis of how the heart sits in the thoracic cavity, often if easy parasternal views are obtainable, the heart is sitting in a more superior and transverse orientation. This may mean that subcostal views will be more challenging in the same patient. The same goes for more inferior, longitudinally positioned hearts. Some patients of course have a panel of beautiful views but this “law” does help the junior ultrasonographer with trusting the skill development process.
As well, rather than just adjusting the depth, modulating the sector width to encompass the heart but not entrap it can also help appraise relevant pathology at hand. Also sometimes hearts can be cut off axis which can over- or under-estimate cavitary size – rotating, tilting, and rocking movements as appropriate can help obtain a more comprehensive set of views after which the most accurate picture can be selected.
It is especially fraught with peril to use IVC assessments in the spontaneously breathing patients to help make these decisions. Perhaps one applicable area of IVC assessment is in passively ventilated patients – distensibility >18% can support a strategy of volume resuscitation, combined with other parameters of course. Otherwise, IVC diameters at the extremes can be helpful – skinny IVCs with large respiratory variation can support plans for fluid resuscitation and plethoric IVCs with little-no respiratory variation should raise caution.
The purpose of this rotation is to familiarize the learner with the applications and indications for critical care ultrasound while also participating in the daily care of the critically ill patients at LHSC’s Critical Care Trauma Centre (CCTC).
A combination of online and offline supervised scanning, e-learning and portfolio development will enable the motivated participant to achieve foundational skills in this explosive field of medicine.
Based on the framework described in the internationally endorsed consensus on critical care ultrasound content and competence, this rotation will focus on:
-Basic critical care echocardiography
-Pleural and lung ultrasonography
-Basic abdominal sonography
-Vascular sonography for procedural guidance
Interested residents at LHSC may contact Rob Arntfield (through his assistant here) for further information. Both local trainees and those from other centres in Canada may participate in this novel elective rotation.
The objectives of this rotation are here for your browsing.
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