Abdomen (pelvis) Flashcards
type de sonde?
curvilinéaire
Préparation de la sonde préscan
Knobology
Dive the depth to centre relevant anatomy.
Recommended starting depth for beginners: 15 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 / OB.
Préparation du pt et prise/orientation de la sonde?
Patient positioning
Supine.
Patient draping
Abdomen exposed from umbilicus down, towel covering waist.
Probe orientation
Longitudinal – Probe held perpendicular to the floor / stretcher with the beam directed towards the patient’s back and the probe marker oriented towards the patient’s head.
Transverse – Probe held perpendicular to the floor / stretcher with the beam directed towards the patient’s back and the probe marker oriented towards patient right.
Probe grip
Longitudinal – Probe held softly between thumb and 2-3 fingers close to the probe face, one to two fingers on patient to enhance proprioception.
Repère externe
Midline just cephalad to symphysis pubis.
Repère interne?
vessie
Anatomie pertinente de cette zone?
Bladder, uterus, vagina, prostate and seminal vesicles, rectum.
Zone d’intérêt?
Females – Vesico- and recto-uterine space.
Males – Rectovesical space.
Techniques (femme)?
Female pelvis:
Longitudinal approach:
Place the probe just cephalad to the symphysis pubis. Identify the bladder. Heel and toe the probe as needed to place the bladder on screen right. Slide the probe from side to side to find/center the uterus at the point where its image is largest and clearest.
Recognize that the vesico-uterine space is between the uterus and the bladder (i.e., anterior to the uterus) and that the recto-uterine space is between the uterus and the rectum (i.e. posterior to the uterus). Free fluid can appear in both locations in the female pelvis.
Sweep from left to right, looking anteriorly and posterior to the uterus (i.e. in the vesico-uterine and recto-uterine spaces) until the uterus completely disappears in both directions.
Transverse approach:
Place the probe just cephalad to the symphysis pubis. Identify the bladder. Sweep the probe caudad to the level of the vagina. This is the starting point for this scan.
Sweep slowly cephalad from the vagina, looking anteriorly and posterior to the uterus (i.e. in the vesico-uterine and recto-uterine spaces) until the uterus completely disappears.
TEchnique (homme)?
Male pelvis:
Longitudinal approach:
Place the probe just above the symphysis pubis. Identify the bladder, prostate (if visible), rectum and seminal vesicles.
Recognize that the recto-vesicular space is posterior to the bladder but cephalad to the seminal vesicles. This is where free fluid would appear in the male pelvis.
Sweep this area slowly from left to right, looking posterior to the bladder for free fluid, until the bladder disappears in both directions
Transverse approach:
Place the probe just cephalad to the symphysis pubis. Identify the bladder. Sweep caudad until you identify the prostate / rectum. Sweep slightly cephalad to find the seminal vesicles. This is the starting point for this scan.
Slowly sweep cephalad from the seminal vesicles, looking posterior to the bladder for free fluid, until the bladder completely disappears.
Truc si la zone d’intérêt n’est pas visible?
If the entire area of interest is not visible:
- Ensure probe is placed right against symphysis pubis.
- Press and hold to displace bowel gas.
- Slide the probe off centre and heel / toe back (in transverse view) or sweep back (in longitudinal view). In situations where the uterus is not midline AND obscured by overlying bowel, the probe is moved AWAY from the uterus and angled back through the bladder. This movement optimizes the use of the bladder as an acoustic window and effectively looks around the bowel gas.
- Fill the bladder. Intravenous fluids are recommended if filling the patient’s bladder is required. Oral fluids are contraindicated as this takes more time and should be avoided in patients who have potential surgical conditions. The use of catheters for installation of fluids followed by clamping may be considered in the setting of trauma, provided no signs of urethral injury are present (blood at the meatus, high-riding prostate, pelvic instability, etc.).
Piège interprétation de l’image?
Pitfalls (Image interpretation)
Misidentifying the seminal vesicles as free fluid.
Misidentifying the prostate as free fluid.
Pièges générations d’images?
Pitfalls (Image generation)
Sweeping too quickly.
Starting the scan in the transverse plane. All pelvic scans should start in the longitudinal plane as this makes pelvic anatomy easy to recognize, even when the bladder is not optimally filled.
Placing the probe too far cephalad. The probe must always be placed initially right against the symphysis pubis to use the bladder as an acoustic window and avoid gas scatter.
Inadequate sweeping (i.e. not sweeping until the uterus in women or bladder in men disappears completely).
Sweeping too far caudad in the transverse view (i.e. past the level of the vagina or prostate).
Not moving far enough from side to side to find the uterus.
Pièges intégration clinique?
Pitfalls (Clinical integration)
Assuming that all pelvic free fluid is acute blood. Free fluid in the pelvis can be a normal variant in both males and females. The finding of free pelvic fluid must always be placed within the clinical context.
Assuming that fluid in the pelvis is only physiologic. Even though free pelvic fluid is quite common, its presence should not be assumed to be benign. Scans should always be repeated. The upper quadrants should be interrogated and other imaging such as CT scanning should be performed based on the clinical context. Any free pelvic fluid should be considered acute blood until proven otherwise if it is suspected to be increasing in volume, if it fills both the recto-uterine and vesico-uterine spaces in women (i.e. the fluid surrounds the uterus) or if it is also present in the upper quadrants.
Autres trucs?
Always place the probe just cephalad to (or on) the symphysis pubis.
Placing the patient in reverse Trendelenburg position may make pelvic free fluid more visible.
Turning the gain down to compensate for acoustic enhancement caused by a full bladder will often prevent ‘wash out’ of a small amount of free pelvic fluid.
Pelvic fluid may sometimes only be visible lateral to the bladder when scanning in the transverse plane. Evaluating each side of the bladder separately will decrease the probability of missing this fluid.
Always ensure the male pelvis is being scanned at right angles to the bladder in the longitudinal plane. If the probe is angled towards the feet then the prostate and seminal vesicles may appear to be in the peritoneal cavity, increasing the chance they may be mistaken for free fluid.
Scan négatif? (femme et homme?)
Negative scan for pelvic free fluid:
Females: Adequate visualization and complete sweep of the vesico-uterine and the recto-uterine spaces in both the longitudinal and transverse planes, without evidence of free pelvic fluid.
Males: Adequate visualization and complete sweep of the recto-vesical space (which requires an adequately filled bladder and identification of the seminal vesicles) in both the longitudinal and transverse planes, without evidence of free pelvic fluid.
