Abdomen (pas Obs) Flashcards
Type de sonde à utiliser?
curvilinéaire
Comment préparer l’edu avant de faire un scan?
Knobology
Dive the depth to centre relevant anatomy.
Recommended starting depth for beginners: 20 cm or machine maximum in adults. Initial depth for pediatric patients varies with age.
Beginners should always set the initial depth deep enough to avoid missing relevant anatomy. With experience, initial depth should be adjusted to account for patient body habitus.
Gain = mid-range.
System preset(s) = abdominal / FAST.
Comment préparer le pt avant le scan? prise et orientation de la sonde?
Patient positioning
Supine.
Patient draping
Males – Torso exposed. Females – Towels tucked into bra bilaterally in upper flank/lower axillae, bra possibly pulled up slightly as needed, abdomen exposed.
Probe orientation
Probe held parallel to the floor / stretcher with the beam directed towards the patient’s midline and the marker oriented towards the patient’s head.
Probe grip
Probe cradled, relaxed hand, probe held close to the probe face, one finger (2nd or 5th) against patient.
repère externe?
Posterior axillary line at level of xiphoid.
repère interne?
Kidney.
autres organes internes avoisinants?
Liver, spleen, kidney, lung, diaphragm, stomach.
Zone d’intérêt a/n des hypochondres?
Right upper quadrant: hepatorenal interface. Left upper quadrant: splenorenal interface and medial area caudal to the diaphragm (i.e. 6 o’clock to 9 o’clock).
Technique HCD?
In the right upper quadrant:
Start scan here.
In both the right and left upper quadrants:*
Start at the intersection of the posterior axillary line and the xiphoid process (i.e. external landmark) and move the probe in the posterior-anterior plane to find the clearest interface between the solid organ and the kidney. The best possible view of the interface is generated when the greatest possible portion of the kidney is seen, and where the kidney’s capsule is at its brightest. The probe is always kept parallel to the stretcher / floor in a longitudinal orientation.
Move the probe cephalad and caudad, in the longitudinal plane to explore the interface, again keeping the probe parallel to the floor / stretcher.
Movements along the longitudinal plane should result only in changes to the kidney’s position on the screen but not its size or shape.
The exploration of the interface in the longitudinal plane is done to achieve two goals. First, to determine the extent and size of the interface. Second, to find the best window(s) to interrogate the interface. Superior views of the interface are often achieved by solely moving the probe cephalad or caudal longitudinally. This can dramatically increase the portion of the interface that can be seen through one particular rib space.
Magnify the image to make the kidney as large as possible on the screen while keeping the spine visible medial (i.e. far field) to the kidney.
Sweep the interface, including the caudal tip of the solid organ(s), first posteriorly and then anteriorly, until the kidney disappears in both directions.
Appropriately utilize troubleshooting maneuvers to see the entire interface in both upper quadrants and the caudal tips of both solid organs.
The entire interface must be visualized and swept, using overlapping sweeps if needed, without any part of the interface being persistently obscured by rib shadows.
Technique HCG?
Start from the best possible view of the splenorenal interface. Then adjust probe location and orientation if needed, using a systematic troubleshooting algorithm, to visualize the medial aspect of the area caudal to the diaphragm (i.e., 6 o’clock to 9 o’clock).
This area must be swept first posteriorly and then anteriorly (or vice-versa) until the diaphragm disappears in both directions.
Comment contourner les côtes?
- Moving in the longitudinal plane: This is the primary troubleshooting maneuver to get around rib shadows and to allow the operator to find the best window to see the interface. This maneuver often involves sending the beam through multiple rib spaces, creating overlapping snapshots of the entire interface. A CPoCUS-IP must be adept at using this movement to assess the upper quadrants properly. This is often the only troubleshooting maneuver required.
- Probe rotation: The probe can be rotated until it is parallel to the ribs, to send the beam through a single intercostal space. This can allow the beam to avoid the ribs entirely. This is a very difficult maneuver, especially for beginners. It should only be attempted when one has become adept at rotation AND one has a relaxed probe grip. This type of grip results in good proprioceptive feedback, allowing the operator to “feel” the probe nestle into the intercostal space. The cephalad aspect of the probe is always rotated posteriorly. Sweeping is still done perpendicular to the beam, even though the probe is now rotated.
- Spontaneous patient respirations: The natural respirations of the patient will often move the interface out from under rib shadows. Interrogation of certain portions of the interface can often be achieved by timing sweeps with these movements.
- Varying patient respirations: The operator may ask the patient to take a deep breath in or out to move the interface out from under rib shadows. This maneuver should not be used as the primary method of generating an optimal view of the interface as it may not be possible to vary patient respiration. Patients with significant thoracic or abdominal trauma may have considerable pain and splinting, not allowing them to take a deep breath. Other patients may not be able to follow requests to vary respirations due to head injury, intoxication or other significant distracting injuries.
5 étapes pour bien scanner HCG?
Diaphragm in the left upper quadrant (LUQ):
To produce a determinate image, a CPoCUS-IP must be able to visualize the medial aspect of the area caudal to the diaphragm (i.e. 6 o’clock to 9 o’clock).
The diaphragm can be quite difficult to image adequately in the LUQ. A methodical troubleshooting algorithm is required to overcome any challenges. To be an efficient scanner, these steps should be followed in order.
Step 1: Find the best view of the interface / kidney. This step is the foundation of all other troubleshooting maneuvers for finding the diaphragm and should never be skipped.
Using the systemic approach outlined in the technique section, it is imperative that a CPoCUS-IP first find the best possible view of the interface. This will be the point at which the greatest possible portion of the kidney is seen, and where the kidney’s capsule is at its brightest.
This step is the foundation of all other troubleshooting maneuvers for finding the diaphragm and should never be skipped.
An adequate portion of the diaphragm often becomes visible solely by using this maneuver. If this is the case, the diaphragm should be swept until it disappears in both directions. Otherwise the operator should move to the next step.
Step 2: Moving cephalad in the longitudinal plane. If the entire medial aspect of the diaphragm (6 o’clock to 9 o’clock) is not seen after Step 1 is performed, the probe should be moved in the longitudinal plane towards the patient’s head.
It is important that this only be done after performing Step 1 well.
Sweep the diaphragm if adequately visualized. If not, move to the next step.
Step 3: Probe rotation. If the entire medial aspect of the diaphragm (6 o’clock to 9 o’clock) is not seen after performing Steps 1 and 2 in sequence, the probe should be rotated. This is done to slip the beam through intercostal spaces AND to align the beam with the diaphragm (which attaches to the spine obliquely).
As with probe rotation to overcome rib shadows, this maneuver is difficult and best performed with a relaxed hand, optimizing proprioceptive feedback.
Sweep the diaphragm, with rotation maintained, if adequately visualized. If not, move to the next step.
Step 4: Sliding anteriorly & sweeping posteriorly (OR moving posteriorly and sweeping anteriorly). If not enough diaphragm is visible after performing the first three steps in sequence (best view of the interface, moving cephalad and probe rotation), the operator should move the probe anteriorly one or two intercostal spaces and then sweep the probe back posteriorly.
Alternatively, the operator can move the probe posteriorly one or two intercostal spaces and then sweep the probe back anteriorly.
These maneuvers should be done with the probe in the same orientation as at the end of step 3 (i.e. rotated). The goal is to improve the acoustic window provided by the spleen AND to align the ultrasound beam with the obliquely positioned diaphragm.
Sweep the diaphragm, with rotation maintained, if adequately visualized. If not, move to the next step.
Step 5: Moving caudad and heeling through the spleen. If not enough diaphragm is visible after performing the first four steps in sequence, the operator should move the probe back to the starting position achieved in step 1. The probe should then be moved caudally in the longitudinal plane AND heeled cephalad, directing the ultrasound beam up through the spleen towards the patient’s head.
This maneuver is usually not as effective as the first 4 steps and therefore should be attempted last.
Trucs pour scanner les organes ‘‘caudaux’’
Caudal tips of the solid organs:
All assessments of the upper quadrants should include sweeping the caudal tips of both the liver and the spleen. Disappearance of the kidney, posteriorly and anteriorly, is used as the end-point for these sweeps.
If the caudal tip of either solid organ is not visualized adequately, the following maneuvers may help:
1. Slide the probe caudally along the longitudinal plane.
- Slide the probe anteriorly. If the caudal tip of the solid organ is not clearly seen (especially when the patient has a large amount of perinephric fat), moving the probe 1 or 2 cm anteriorly may improve the image. Once visualization of the caudal tip is optimized with this maneuver, it should be swept until the kidney disappears in both directions. Please note that this maneuver may initially impair the ability to see the kidney but can be considered acceptable if the kidney reappears while sweeping posteriorly.
- Rotate the probe. If the caudal tip is still not visible after moving anteriorly (or if the image of the kidney is lost), the probe can be rotated, whether or not there is a rib shadow at the caudal tip. Once the caudal tip is visualized it is swept while maintaining probe rotation. As with probe rotation to overcome rib shadows, this maneuver is difficult and best performed with a relaxed hand, optimizing proprioceptive feedback.
Pièges de l’interprétation de l’image?
Pitfalls (Image interpretation)
Attempting to interpret a part of the interface that has a rib shadow persistently obscuring it.
Mistaking perinephric fat for free fluid.
Mistaking clotted blood for perinephric fat.
Mistaking a blood vessel for free fluid.
Mistaking ascites for blood.
Mistaking free urine for blood
Mistaking peritoneal dialysate for blood.
Mistaking intraluminal bowel fluid for blood.
Mistaking the stomach wall for the diaphragm in the LUQ.
Pièges de la génération d’image?
Sweeping too quickly.
Probe marker oriented incorrectly (i.e. caudally).
Starting the scan too anteriorly.
Not finding the point at which the greatest possible portion of the kidney is seen, and where the kidney’s capsule is at its brightest.
Gripping the probe too tightly.
Holding the probe incorrectly.
Moving the probe in more than one plane at a time (i.e. moving anteriorly or posteriorly while attempting to move only longitudinally).
Following the contour(s) of the patient. This happens when the probe is held perpendicular to the patient rather than parallel to the floor while moving anteriorly or posteriorly. It can also occur when moving longitudinally if the operator heels or toes the probe rather than keeping the centre of the probe against the body.
Dropping the handle of probe (often occurs when reaching across the patient’s body to scan the opposite upper quadrant).
Moving the probe face while sweeping (i.e. ‘painting’).
Over-rotating the probe.
Rotating in the wrong direction.
Getting ‘gassed out’ by the stomach in the LUQ. If the probe moves or sweeps too anteriorly in LUQ, the interface often be obscured by stomach gas.
Attempting to move around ribs by heeling the probe and not sliding the probe in the longitudinal plane.
Using troubleshooting techniques in the wrong sequence. This is especially true for the diaphragm maneuvers, which must be done in the correct order.
Pièges de l’intégration clinique?
Pitfalls (Clinical integration)
Assuming that the absence of free fluid in an acute trauma patient rules out solid organ, hollow viscus, or vascular injury. The absence of visible free fluid only rules out significant hemoperitoneum (greater than 250 ml of fluid) at one specific moment in time. The clinical impression of the treating clinician must always supersede any PoCUS finding.
Declaring a negative scan in patients who have had multiple prior surgeries (i.e. the ‘battlefield abdomen’). Free fluid can be sequestered away from areas accessible by PoCUS due to scar tissue. If no free fluid is visible in such patients, the scan must be documented as indeterminate.
Relying on a negative scan in a trauma patient whose presentation is delayed. After several hours, fresh blood can become clotted and more echogenic. This blood might be mistaken for perinephric fat or missed entirely due to its similarity to solid organ tissue density.
Not repeating negative scans in high risk patients. A negative upper quadrant scan may become positive in a short time. Serial scans are very valuable.
Assuming that free fluid is always blood. Free intraperitoneal fluid can be caused by numerous pathologies other than bleeding from trauma (e.g. ascites from liver or ovarian disease). The clinical context of the patient should mandate what PoCUS scans are performed and how PoCUS findings are integrated into the diagnostic algorithm. The presence of a positive finding must be treated as a single data point within the entire diagnostic impression of the treating clinician.
