Intro to POCUS Lung Ultrasound Pt. 1

Transcript

• 00:03In this lecture we will
• 00:04review pediatric point of care
• 00:07lung ultrasound.
• 00:15In general, the approach to
• 00:17your patients will differ depending
• 00:18on the clinical picture and
• 00:20the presenting symptoms.
• 00:22The most common pathology you'll
• 00:24be looking for is the
• 00:25presence or absence of a
• 00:26pneumothorax,
• 00:27the presence or absence of
• 00:29a pleural effusion,
• 00:30the presence or absence of
• 00:32lung tissue consolidation
• 00:34or fluid filled alveolar spaces.
• 00:41So one common thread in
• 00:42pediatric patients is that they
• 00:44may not be too cooperative
• 00:45with your exam. They may
• 00:47be overly tired, fussy,
• 00:49irritable,
• 00:50arching their backs and bringing
• 00:51the scapula together so as
• 00:53to not expose the posterior
• 00:55lung field, or just simply
• 00:56trying to run away.
• 00:58Some potential tricks of the
• 01:00trade include engaging a caregiver
• 01:02so that the child feels
• 01:04more comfortable,
• 01:05having an infant or toddler
• 01:07give their parent a hug.
• 01:09This will provide both a
• 01:10sense of comfort and expose
• 01:11their back for a good
• 01:13lung examination.
• 01:14And finally, I would encourage
• 01:16distraction in whatever
• 01:18means possible.
• 01:20And yes, screen time is
• 01:22okay during a pediatric lung
• 01:23pocus.
• 01:29So to improve your patient
• 01:31cooperation and optimize your time
• 01:33performing lung pocus, you may
• 01:35consider
• 01:36getting some warm gel.
• 01:38This can be done with
• 01:39some relatively inexpensive
• 01:41commercially available products if you're
• 01:43using,
• 01:44typical
• 01:45gel
• 01:46tubes.
• 01:47If for some reason you
• 01:48happen to be using gel
• 01:49packets, a hack that I
• 01:50like to use is to
• 01:51put one or two in
• 01:52my pocket at the beginning
• 01:53of a shift and then
• 01:54have them at the ready
• 01:55when the timing is right.
• 01:57Now in terms of the
• 01:58transducer, your probe selection is
• 02:00gonna depend a lot on
• 02:01the question
• 02:07that you're trying to answer.
• 02:07In general, for younger patients
• 02:07and whom you're concerned mostly
• 02:07about pneumonia, a high frequency
• 02:09linear transducer is gonna provide
• 02:11excellent resolution.
• 02:13The linear transducer would be
• 02:15my choice as well for
• 02:16pneumothorax evaluation.
• 02:18That said, there are many
• 02:19instances where a low frequency
• 02:21curvilinear transducer
• 02:22will be an adequate choice,
• 02:25and I certainly would use
• 02:26this probe in my initial
• 02:27assessment for a pleural effusion.
• 02:33So when clinical concern exists
• 02:35for either pneumothorax
• 02:36or pneumonia,
• 02:38your probe of choice will
• 02:39be the high frequency
• 02:41linear transducer,
• 02:42and you will start by
• 02:43looking at the apex of
• 02:44the lung over the anterior
• 02:46lung fields.
• 02:48If clinical concerns exist for
• 02:50a pleural effusion,
• 02:52like would be the case
• 02:53in the context of trauma,
• 02:55then using a curvilinear probe
• 02:57to interrogate the lung basis
• 02:59would be my preferred initial
• 03:01approach.
• 03:04A pneumothorax
• 03:05occurs when air accumulates in
• 03:07the pleural space between the
• 03:08visceral and parietal pleura.
• 03:11The air buildup in this
• 03:12space, even when it is
• 03:13in small quantities,
• 03:16create visual changes on your
• 03:17ultrasound screen, which will help
• 03:19you make this diagnosis.
• 03:23For the evaluation of pneumothorax,
• 03:26the following steps should be
• 03:27followed.
• 03:28First, it is important to
• 03:30position the patient in the
• 03:31supine position.
• 03:32This will increase your overall
• 03:34sensitivity for small pneumothorax
• 03:36detection as air
• 03:38will rise to the top,
• 03:39and therefore, in a supine
• 03:40position, that pneumothorax will be
• 03:42present between the probe and
• 03:44the chest wall.
• 03:45Evaluation of the apex with
• 03:47a linear probe over the
• 03:48midclavicular
• 03:49line with the indicator to
• 03:50the head is the ideal
• 03:52starting point. You will look
• 03:53for signs of lung sliding.
• 03:56If lung sliding happens to
• 03:57be absent, then you will
• 03:58want to slide the probe
• 03:59down the chest wall to
• 04:01get a general sense of
• 04:02how big of a pneumothorax
• 04:03you will be dealing with.
• 04:07So let's start by looking
• 04:08at the appearance of normal
• 04:10lung tissue
• 04:11as seen by ultrasound.
• 04:13As discussed, you will place
• 04:14the linear probe, we can
• 04:15get indicator to the head.
• 04:16If you look at the
• 04:18screenshot on the left, that
• 04:19indicator is represented by the
• 04:22pea.
• 04:23The ribs can be seen
• 04:24in cross section with posterior
• 04:26acoustic enhancement,
• 04:27and the goal here is
• 04:28for the pleura to be
• 04:29at the center of your
• 04:30screen.
• 04:31Note that the ultrasound machine
• 04:33is set on lung window
• 04:34setting, and this makes the
• 04:36pleura bright or echogenic.
• 04:38Right above the pleura and
• 04:40between the ribs, you will
• 04:41find your intercostal muscle.
• 04:43And again, the first echogenic
• 04:45line
• 04:46represents the pleural interface.
• 04:48Now on the video on
• 04:49the right, you can see
• 04:50that there is motion, movement,
• 04:53shimmering
• 04:54of the pleura, which represents
• 04:56normal sliding of the visceral
• 04:58and parietal components during typical
• 05:00respirations.
• 05:02In addition, you will see
• 05:03additional
• 05:04horizontal
• 05:06lines also echogenic, which we
• 05:08refer to as a lines.
• 05:10This is a normal reverberation
• 05:12artifact that is seen in
• 05:13healthy lung tissue. We will
• 05:15come back to these a
• 05:16lines at another point in
• 05:18this presentation.
• 05:21So when air collects between
• 05:23the visceral and parietal pleura,
• 05:25the lack of lung sliding
• 05:27that result will cause physiologic
• 05:29changes easily detectable by ultrasound.
• 05:35Your first assessment is going
• 05:37to be a careful visual
• 05:38assessment of the pleura. These
• 05:40images represent lung ultrasound findings
• 05:43of a patient with a
• 05:43right sided pneumothorax.
• 05:45Note the normal clip on
• 05:46the left. You can see
• 05:48normal lung sliding with appearance
• 05:50of shimmering or sometimes described
• 05:52as ants marching on a
• 05:54log,
• 05:55which represents normal motion between
• 05:57the visceral and parietal pleura.
• 05:59In contrast on the abnormal
• 06:00side, you can see that
• 06:01that pleura looks stuck together.
• 06:04There is no discrete motion
• 06:05that can be seen. In
• 06:07this case, the probe was
• 06:08placed in the mid axillary
• 06:09line around t four precisely
• 06:12where a chest tube or
• 06:13pigtail catheter would typically be
• 06:16placed.
• 06:19So to quantify the size
• 06:20of pneumothorax,
• 06:21you want to identify its
• 06:23transition
• 06:24zone, which many will refer
• 06:25to as lung point. During
• 06:27expiration,
• 06:28air tracking into the pleural
• 06:30space will expand, while inspiration
• 06:32leads to air accumulation
• 06:34within the lungs themselves.
• 06:36Depending on the size of
• 06:37the pneumothorax, you will be
• 06:38able to
• 06:39determine at what point in
• 06:40the thorax a pneumothorax
• 06:42meets
• 06:43and deposes aerated lung with
• 06:46preserved visceral and parietal pleural
• 06:48sliding.
• 06:49Lung point is the most
• 06:51specific ultrasound finding for pneumothorax
• 06:53and can be used to
• 06:54distinguish from other causes of
• 06:56abnormal lung sliding such as
• 06:58pleurodesis.
• 07:01In this video clip, you
• 07:03can see lung point being
• 07:04demonstrated.
• 07:05The pleura again is the
• 07:07echogenic line seen here between
• 07:08the ribs. On the left
• 07:10side of the screen, you
• 07:11can see motion, which represents
• 07:13movement between the visceral and
• 07:15parietal pleura, while on the
• 07:16right side of the screen,
• 07:18the pleural line is still
• 07:20consistent with a pneumothorax.
• 07:25Now finally, you can use
• 07:27m mode, which stands for
• 07:29motion mode, to confirm,
• 07:31your suspicion for the presence
• 07:32or absence of a pneumothorax.
• 07:34So here you drop the
• 07:36motion line over the center
• 07:37of the pleura,
• 07:39and this will split the
• 07:40screen and
• 07:41the bottom half will detect
• 07:42motion over time. So the
• 07:44same concept applies. When there
• 07:46is
• 07:47opposition and normal sliding between
• 07:49the visceral and parietal pleura,
• 07:51you will see a distinct
• 07:52transition
• 07:53as your ultrasound device is
• 07:54picking up this movement.
• 07:56This is often referred to
• 07:57as a seashore
• 07:59sign, which is a good
• 08:00thing because most of us
• 08:01would rather be at the
• 08:02beach than listening to this
• 08:03lecture.
• 08:07In contrast, when a pneumothorax
• 08:08is present,
• 08:10your ultrasound cannot detect motion
• 08:12between the pleura. Therefore, the
• 08:14appearance of a barcode will
• 08:16be present,
• 08:17which is only fitting because
• 08:18the next steps are likely
• 08:20to add additional expenses to
• 08:22the health care system.
• 08:26So here we have a
• 08:27case of a fourteen year
• 08:28old with a spontaneous pneumothorax
• 08:31who was awoken up suddenly
• 08:32with some shortness of breath
• 08:34and chest pain.
• 08:35Ultrasound images of the apex
• 08:37are significant
• 08:38for absent lung sliding on
• 08:40the video clip. In addition,
• 08:42when m mode was applied,
• 08:43there was a positive barcode
• 08:45sign with straight horizontal lines
• 08:47above and below the pleura
• 08:49as no transition zone or
• 08:51lung point was seen. By
• 08:52ultrasound, this patient was triaged
• 08:54into the major treatment area
• 08:56where chest x rays thirty
• 08:58minutes later confirm the presence
• 09:00of a large right sided
• 09:02pneumothorax.
• 09:04Let us now shift gears
• 09:06and look at ultrasound for
• 09:07the detection of pleural effusion,
• 09:10be it simple fluid,
• 09:12complex fluid, or hemothorax.
• 09:18So for assessment of pleural
• 09:19effusion, you will want a
• 09:21curvilinear probe,
• 09:23which allows for greater tissue
• 09:25penetration.
• 09:26And you can do this
• 09:27in the supine position, again,
• 09:28with the indicator to the
• 09:29patient's head.
• 09:31Now here, you want to
• 09:32evaluate
• 09:33at the level of the
• 09:34diaphragm
• 09:35with a starting point roughly
• 09:37around the mid axillary line.
• 09:39You'll have to obtain views
• 09:41in both the right upper
• 09:41quadrant and the left upper
• 09:43quadrant for a complete exam.
• 09:45As an example, let's take
• 09:46a look at the images
• 09:47created in the left upper
• 09:49quadrant.
• 09:50The image produced should contain
• 09:52the following anatomy,
• 09:54ribs,
• 09:56spleen towards the top left
• 09:58of the screen,
• 09:59kidney towards the bottom right
• 10:01of the spleen,
• 10:02the diaphragm, which is a
• 10:04thin, curved, echogenic structure,
• 10:07which marks the transition zone
• 10:09between abdomen and lung. In
• 10:12normal circumstances,
• 10:13you will see mirror imaging
• 10:15or reflection of the spleen
• 10:16tissue
• 10:17flipped behind
• 10:19the diaphragm.
• 10:20However, when fluid collects at
• 10:23the costophonic
• 10:24angle,
• 10:25instead of spleen tissue reflected
• 10:26behind the diaphragm, you will
• 10:28now be able to detect
• 10:29a fluid collection,
• 10:31which will also make the
• 10:32thoracic spine more easy to
• 10:33identify.
• 10:38In this video clip, we
• 10:39can see normal appearance of
• 10:42anatomy in the left upper
• 10:43quadrant.
• 10:44The spleen is a relatively
• 10:46homogeneous
• 10:47structure, which appears in the
• 10:48middle of the screen.
• 10:49To the right of the
• 10:50screen and below the spleen,
• 10:52you will see the left
• 10:53kidney.
• 10:54The lungs will be above
• 10:56and to the left of
• 10:56the spleen and not visible
• 10:58on these images.
• 10:59The most important structure to
• 11:01note is the diaphragm,
• 11:03which will demarcate the area
• 11:04of the costropenic
• 11:05angle where fluid would build
• 11:07up should it be present.
• 11:09But in this case, we
• 11:10see mirror imaging and reflection
• 11:11of the spleen behind the
• 11:13diaphragm, which you would expect
• 11:15in normal circumstances.
• 11:20In this video clip, you
• 11:22can see a moderate sized
• 11:23portal diffusion by ultrasound with
• 11:25its corresponding chest x-ray.
• 11:27The fluid is accumulating above
• 11:29the liver and above the
• 11:30diaphragm.
• 11:31And in this instance, you
• 11:33can also see diseased lung
• 11:34tissue within the pleural effusion.
• 11:36An additional important finding is
• 11:38the thoracic spine sign,
• 11:41which can only be visualized
• 11:43when there's enough fluid present
• 11:44between the ultrasound probe and
• 11:46the thoracic vertebral body that
• 11:48allows for sufficient ultrasound transmission
• 11:51to reach and be reflected
• 11:53by the thoracic spine.
• 11:55This is a key finding
• 11:57to look for when diagnosing
• 11:58pleural effusions
• 12:00or hemothorax in the setting
• 12:02of trauma.
• 12:06In this video clip, we
• 12:07can see a large postoperative
• 12:09pleural effusion in a three
• 12:11year old who has status
• 12:12post liver transplantation.
• 12:14You can clearly make out
• 12:15a thoracic spine sign and
• 12:18see lung tissue movement within
• 12:20this large fluid collection.
• 12:25In this case, we can
• 12:27see a massive
• 12:29left sided
• 12:30paranemonic effusion
• 12:32in an eight year old
• 12:33who was eventually diagnosed with
• 12:35pneumonia
• 12:36caused by group a strep,
• 12:38which grew out of her
• 12:39thoracentesis
• 12:40fluid.
• 12:44In contrast, smaller pleural effusions
• 12:46may be more subtle to
• 12:47pick up, especially when a
• 12:49coexisting pneumonia is present.
• 12:51In this example, we have
• 12:53an eleven year old with
• 12:54a right lower lobe pneumonia
• 12:55as seen by X-ray.
• 12:57In this particular ultrasound, there's
• 12:59only a small area that
• 13:01appears hypoechoic
• 13:03with a visible spine sign
• 13:04just deep to this collection.
• 13:06Lung hepatization is present, so
• 13:08this ultrasound would be diagnostic
• 13:10for pneumonia with a small,
• 13:11nondrainable pleural effusion.
• 13:14In this next example, we
• 13:15have a twelve year old
• 13:16with right lower lobe pneumonia.
• 13:18The costophrenic angle does have
• 13:20a blunted appearance on chest
• 13:21x-ray, making a diagnosis of
• 13:23effusion difficult.
• 13:25However, ultrasound evaluation of this
• 13:27area reveals
• 13:28hepatization
• 13:29and bronchograms, which are consistent
• 13:31with infiltrate alone, and there's
• 13:32no secondary pleural effusion to
• 13:34be seen.
• 13:35Let's take a moment to
• 13:36look at these two ultrasound
• 13:38clips side by side so
• 13:39you can appreciate the difference
• 13:41between no effusion
• 13:43and a small effusion.
• 13:52Here you can see a
• 13:53rather complex complex pleural effusion
• 13:55with internal septations and honeycomb
• 13:57like appearance.
• 13:59Note at the bottom of
• 14:01the screen that the thoracic
• 14:03spine can be clearly visualized.
• 14:08Now if you happen to
• 14:10be using a linear probe
• 14:11to assess for pneumothorax
• 14:14or a pediatric pneumonia, you
• 14:15should be able to detect
• 14:16pleural effusion should it be
• 14:18present.
• 14:19And the appearance of fluid
• 14:20within the visceral and parietal
• 14:22pleura will give you a
• 14:24much different image than if
• 14:25that potential space was occupied
• 14:28by air.
• 14:30So let's take a look
• 14:31at this clip with the
• 14:32pleural effusion as seen by
• 14:34a linear probe. First, we'll
• 14:35make note of the ribs,
• 14:36which are superficial bony structures
• 14:38that should be bright or
• 14:39echogenic, but also cast a
• 14:41shadow.
• 14:42The pleural effusion will displace
• 14:44the pleura posteriorly.
• 14:45And in this case, we
• 14:46lose our normal sonographic lung
• 14:48architecture as there is no
• 14:50reverberation
• 14:51a line artifacts to be
• 14:52seen.
• 14:53So the pleural effusion here
• 14:55can be detected as an
• 14:56anechoic fluid collection that is
• 14:58below the ribs but in
• 15:00front of the lungs.
• 15:04And in this example, we
• 15:05can see a pleural effusion
• 15:07filling in the left costophrenic
• 15:09angle.
• 15:10With the linear probe, you
• 15:12can actually see tremendous resolution
• 15:14of the diaphragm and note
• 15:16that it has a double
• 15:17line appearance as the muscle
• 15:19is found between the parietal
• 15:21pleura and the lying of
• 15:22the peritoneum.
• 15:23Due to the poor penetration
• 15:25available with a linear probe,
• 15:27we cannot reliably assess for
• 15:29mirror imaging artifact
• 15:31nor for the presence of
• 15:32a thoracic spine sign.