Name: optic nerve sheath point of care ultrasound: image acquisition
Uploaded: 2023-08-18T13:50:00
Description: Watch this Scientific Journal Video about Optic Nerve Sheath Point of Care Ultrasound: Image Acquisition at JoVE.com

This effort was partially sponsored by the US Government under Other Transactions (W81XWH-15-9-0001/W81XWH-19-9-0015) and the Medical Technology Enterprise Consortium (MTEC) under 19-08-MuLTI-0079.

This procedure is in accordance with the ethical standards of the institutional committee on human experimentation and with the Helsinki Declaration of 1975. Ultrasound is considered minimal risk procedure, so written consent from the patient is not required.
1. Probe selection
NOTE: ONSD POCUS can be performed with a multitude of different transducers. To evaluate abnormalities in suspected cases of increased ICP, choose a linear high-frequency (5-14...

<ol>
	<li>Hansen, H. C., Helmke, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+the+optic+nerve+sheath+response+to+changing+cerebrospinal+fluid+pressure:+ultrasound+findings+during+intrathecal+infusion+tests.">Validation of the optic nerve sheath response to changing cerebrospinal fluid pressure: ultrasound findings during intrathecal infusion tests.</a> Journal of Neurosurgery. 87 (1), 34-40 (1997).</li><li>Bauerle, J., Lochner, P., Kaps, M., Nedelmann, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-+and+interobsever+reliability+of+sonographic+assessment+of+the+optic+nerve+sheath+diameter+in+healthy+adults.">Intra- and interobsever reliability of sonographic assessment of the optic nerve sheath diameter in healthy adults.</a> Journal of Neuroimaging. 22 (1), 42-45 (2012).</li><li>Lochner, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-+and+interobserver+reliability+of+transorbital+sonographic+assessment+of+the+optic+nerve+sheath+diameter+and+optic+nerve+diameter+in+healthy+adults.">Intra- and interobserver reliability of transorbital sonographic assessment of the optic nerve sheath diameter and optic nerve diameter in healthy adults.</a> Journal of Ultrasound. 19 (1), 41-45 (2016).</li><li>Shokoohi, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optic+nerve+sheath+diameter+measured+by+point-of-care+ultrasound+and+MRI.">Optic nerve sheath diameter measured by point-of-care ultrasound and MRI.</a> Journal of Neuroimaging. 30 (6), 793-799 (2020).</li><li>Montorfano, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mean+value+of+B-mode+optic+nerve+sheath+diameter+as+an+indicator+of+increased+intracranial+pressure:+A+systematic+review+and+meta-analysis.">Mean value of B-mode optic nerve sheath diameter as an indicator of increased intracranial pressure: A systematic review and meta-analysis.</a> The Ultrasound Journal. 13 (1), 35 (2021).</li><li>Jeon, J. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correlation+of+optic+nerve+sheath+diameter+with+directly+measured+intracranial+pressure+in+Korean+adults+using+bedside+ultrasonography.">Correlation of optic nerve sheath diameter with directly measured intracranial pressure in Korean adults using bedside ultrasonography.</a> PLoS One. 12 (9), e0183170 (2017).</li><li>Maissan, I. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonographic+measured+optic+nerve+sheath+diameter+as+an+accurate+and+quick+monitor+for+changes+in+intracranial+pressure.">Ultrasonographic measured optic nerve sheath diameter as an accurate and quick monitor for changes in intracranial pressure.</a> Journal of Neurosurgery. 123 (3), 743-747 (2015).</li><li>Sedwick, L. A., Burde, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Unilateral+and+asymmetric+optic+disk+swelling+with+intracranial+abnormalities.">Unilateral and asymmetric optic disk swelling with intracranial abnormalities.</a> American Journal of Ophthalmology. 96 (4), 484-487 (1983).</li><li>Chen, L. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasonic+measurement+of+optic+nerve+sheath+diameter:+a+non-invasive+surrogate+approach+for+dynamic,+real-time+evaluation+of+intracranial+pressure.">Ultrasonic measurement of optic nerve sheath diameter: a non-invasive surrogate approach for dynamic, real-time evaluation of intracranial pressure.</a> British Journal of Ophthalmology. 103 (4), 437-441 (2019).</li><li>Copetti, R., Cattarossi, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optic+nerve+ultrasound:+artifacts+and+real+images.">Optic nerve ultrasound: artifacts and real images.</a> Intensive Care Medicine. 35 (8), 1488-1489 (2009).</li><li>Aspide, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+proposal+for+a+new+protocol+for+sonographic+assessment+of+the+optic+nerve+sheath+diameter:+The+CLOSED+protocol.">A proposal for a new protocol for sonographic assessment of the optic nerve sheath diameter: The CLOSED protocol.</a> Neurocrit Care. 32 (1), 327-332 (2020).</li><li>Robba, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound+non-invasive+measurement+of+intracranial+pressure+in+neurointensive+care:+A+prospective+observational+study.">Ultrasound non-invasive measurement of intracranial pressure in neurointensive care: A prospective observational study.</a> PLoS Medicine. 14 (7), e1002356 (2017).</li><li>Anas, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transorbital+sonographic+measurement+of+normal+optic+sheath+nerve+diameter+in+Nigerian+adult+population.">Transorbital sonographic measurement of normal optic sheath nerve diameter in Nigerian adult population.</a> The Malaysian Journal of Medical Sciences. 21 (5), 24-29 (2014).</li></ol>

The most critical steps of this protocol are ensuring the correct settings are used, such as ophthalmic or small parts, to minimize the energy transmitted to the eye. Additionally, ensuring that the optic nerve and not a blooming artifact is being measured is important.
Within diagnostic POCUS, the evaluation of the ONSD is well-suited to investigating patients with traumatic brain injury to evaluate if there is increased ICP. Although invasive intracranial monitoring remains the gold standard...

The goal of this protocol is to allow bedside providers to rapidly evaluate patients for intracranial hypertension in a non-invasive fashion using point-of-care ultrasound. In recent years, bedside decision-making and treatment have been augmented by the emergence of point-of-care ultrasound (POCUS). POCUS involves the use of ultrasound for diagnostic or procedural guidance by a patient&#39;s primary treatment provider. This article focuses on the diagnostic POCUS of the optic nerve sheath.
The rationale behind this technique is that the optic nerve and sheath communicate with the central nervous system. Specifically, the subarachnoid space extends from inside the skull around the optic nerve. Thus, when the intracranial pressure increases, the optic nerve sheath increases in size. It has been shown in studies with magnetic resonance imaging (MRI) and computed tomography (CT) that the optic nerve does not change in size with increased ICP, but the optic nerve sheath does. The vitreous of the eye provides excellent transmission of sound waves, resulting in the optic nerve being clearly visible as a hypoechoic structure inserted on the posterior eye, with the sheath visible around it. For these reasons, ultrasound of the optic nerve sheath has been used to detect elevated ICP, thus allowing the diagnosis of potentially life-threatening instances of increased ICP1.
However, despite its clinical significance, the proficiency of physicians in using ONSD POCUS is variable2,3, which limits the appropriate use of this modality4. This study aims to describe a time-efficient yet thorough image acquisition protocol for diagnostic ONSD POCUS and to illustrate the abnormal findings commonly found in clinical practice. Multiple imaging protocols have been described in the literature, and they present variations in the structural interpretation, ultrasound settings, marker placement, and scan technique5. Different marker points have varying sensitivity to changes in ICP, and the placement affects the ability to distinguish between patients with normal and high ICP. For these reasons, in this paper, we outline a standard technique to obtain optic nerve sheath images and measure them consistently.
Differences in the measurement location and technique have resulted in widely different thresholds of what is considered to be an abnormal optic nerve sheath5,6. In a recent meta-analysis, the average ONSD for patients without intracranial hypertension was 4.1 mm, and the average ONSD for those with increased ICP was 5.6 mm. A generally accepted threshold for a dilated ONSD is 5.5 mm, but a change in ONSD from a normal baseline is much more predictive if a baseline is available. In the context of severe TBI, the ONSD of both eyes seems to change together7.&#160;There are some individual cases of increased ONSD on one side, but this is rare8.
There are additional challenges in the measurement of ONSD in the severe traumatic brain injury (TBI) population. Patients with severe TBI (defined as having a Glasgow coma score of &#60;8) are not alert enough to follow commands. This means a different approach is required to measure the nerve in this population compared to in patients being evaluated in an ophthalmology office in an elective fashion for neuritis. An A-scan can be used to measure the optic nerve in a cooperative patient that can hold their eye still for a length of time, but this is not a useful technique in TBI patients, so a B-scan is the standard technique (see step 2.7 below).
The use of this method and protocol should be considered for patients for whom there are concerns regarding intracranial hypertension but who do not have an intracranial monitor in place. Specific patient populations that may benefit are trauma patients with a clinical concern for traumatic brain injury in the prehospital or emergency room setting. Additionally, patients in the ICU with a sudden change in neurologic status are good candidates for ONSD POCUS.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Butterfly iQ+ with USB-C 2.0</td>
			<td>Butterfly</td>
			<td>n/a</td>
			<td>Used to obtain one of the images</td>
		</tr>
		<tr>
			<td>Clarius L7HD Portable Ultrasound Machine</td>
			<td>Clarius</td>
			<td>n/a</td>
			<td>Used to obtain one of the images</td>
		</tr>
		<tr>
			<td>Ultrasound Gel</td>
			<td>Parker</td>
			<td>n/a</td>
			<td>Used to obtain all images</td>
		</tr>
		<tr>
			<td>Transparent dressing</td>
			<td>3M</td>
			<td>9534HP</td>
			<td>Used to protect eye</td>
		</tr>
	</tbody>
</table>

optic nerve sheath point of care ultrasound: image acquisition

The goal of this protocol is to develop a standardized method for acquiring images of the optic nerve sheath and measuring the optic nerve sheath diameter (ONSD). Diagnostic ultrasound of the ONSD to detect intracranial hypertension has traditionally faced many problems because of methodologic discrepancies. Due to inconsistencies in the measuring techniques, the potential for ONSD to become a non-invasive bedside monitoring tool for ICP has been hampered. However, establishing a transparent, consistent methodology for measuring the ONSD would support its use as a valid and reliable method of identifying intracranial hypertension. This is important as it has both high sensitivity and specificity in acute care settings. This narrative review describes ONSD POCUS image acquisition, including patient positioning, transducer selection, probe placement, the acquisition sequence, and image optimization. Further, visual aids are provided to assist in real-time during image acquisition. This method should be considered for patients for whom there are concerns regarding intracranial hypertension but who do not have an intracranial monitor in place.

There are several findings that can be seen on the POCUS of the optic nerve sheath and several pitfalls that can occur in the measurements. As can be seen in Figure 5, the nerve typically heads back from the eye at an angle when the eye is in a neutral position. In patients undergoing elective ultrasound of the eye for optic neuritis, for example, the patient is typically asked to move the eye and straighten the nerve to facilitate the measurement of the diameter along the axis of the nerve....

Watch this Scientific Journal Video about Optic Nerve Sheath Point of Care Ultrasound: Image Acquisition at JoVE.com

Optic Nerve Sheath Point of Care Ultrasound: Image Acquisition

Point-of-care ultrasound (POCUS) of the optic nerve sheath diameter (ONSD) has been shown to be useful in identifying patients with increased intracranial pressure (ICP). However, the non-standardized technique for this POCUS has hampered its use. We present a standardized image acquisition protocol for use in the acute care setting.

The goal of this protocol is to develop a standardized method for acquiring images of the optic nerve sheath and measuring the optic nerve sheath diameter ...

Point of Care Ultrasound of the Optic Neuro Sheath Diameter is a useful technique in identifying patients with elevated intracranial pressure. It can be used outside of an ICU because it does not require any invasive techniques, so it can be used in the emergency room or potentially even in the pre-hospital setting. This technique can be used immediately upon the patient's arrival and is easily repeatable.However, the lack of standardization has hampered its widespread use. Here, we present a standardized acquisition protocol. This technique is targeted to patients with severe traumatic brain injury.It can help determine if there is elevated intracranial pressures, which may require specific therapies. To begin, press the select scanner tab on an ultrasound machine and select a linear high frequency probe. Allow the probe to connect wirelessly.For setting up the ultrasound, go to applications and choose ocular or small parts. Check the frequency of the scanner. Set the depth to four centimeters for adult patients.Adjust the depth by scrolling up or down on the touch screen. Set the focal zone to 2.5 centimeters. Check the mechanical index and thermal index.Set the video capture length to at least four seconds. Then select the mode as B mode, and select two dimensional gray scale ultrasound. Patients that are candidates for this procedure are those with concern for intracranial hypertension, such as those with severe traumatic brain injury.Exclude patients with ocular trauma. Position the patient in the default position with the head of the bed at 30 degrees. To perform the scan, apply the ultrasound gel to cover the length of the transducer.Close the patient's eyelid and use a transparent film dressing to hold it closed to prevent corneal abrasion or eye damage. Position the probe for the transverse view over the pupil. Center the probe over the pupil and sweep or fan it over the eye.The globe will be hypoechoic with a distinct transition visible at the back of the eye. Identify the optic nerve as a linear hypoechoic structure posterior to the globe. The sheath will be visible as a hypoechoic boundary of the nerve.Attempt to obtain a view with the nerve headed directly posterior from the back of the eye. Ensure the nerve is visible three millimeters posterior to the globe. Once the adequate view is acquired, take a video of the optic nerve sheath.Then scroll back on the video until the maximum diameter of the optic nerve sheath is seen. Alternatively, press the freeze button when at the maximum ONSD, and use the review slider to ensure that the maximum ONSD has been captured. To measure the nerve, press the annotation button, select the distance caliper.Using the caliper function, measure three millimeters posterior from where the optic nerve attaches to the retina. Press the distance caliper again and measure the outermost lateral borders of the optic nerve sheath. Save the annotated image by pressing the save button on the bottom right of the screen.To obtain a sagittal view, center the probe on the eye. Follow the same steps. As for the transverse view, obtain an adequate image and measure the ONSD.When taking measurements, when the eye is in a neutral position, the nerve typically heads back at an angle. Patients can be requested to move the eye so that the nerve is headed straight back. In cases where commands cannot be followed, for example, in patients with traumatic brain injury, the nerve will head back at an angle.It is recommended to measure along the axis of the nerve if it does not head straight back. It is also essential to be aware of potential pitfalls such as mistaking the optic nerve for its sheath, or not using settings or probes with sufficient resolution to distinguish the sheath and nerve. Also, acoustic artifacts like blooming can create interference and misreading.A blooming artifact from structures on the posterior eye shows that there is no rounded nerve head, no sheath, and the shadow appears very rectangular. Whereas when the optic nerve and sheath are visible, the rounded head of the nerve and the sheath are clearly seen. A common struggle in Point Of Care Ultrasound for the Optic Nerve Sheath Diameter is finding the nerve on a sweep.This can be mitigated by gently rocking the probe back and forth until it comes into view, and by angling the probe slightly towards the midline. Additional to this technique, you can also use color flow doppler to help identify the optic nerve. This can help differentiate it from other artifacts that may be present in the image.

optic-nerve-sheath-point-of-care-ultrasound-image-acquisition

Research

JoVE Journal

Medicine

Image Acquisition using Portable Sonography for Emergency Airway Management

With its increasing popularity and accessibility, portable ultrasonography has been rapidly adapted not only to improve the perioperative care of patients, but also to address the potential benefits of employing ultrasound in airway management. The benefits of point of care ultrasound (POCUS) include its portability, the speed at which it can be utilized, and its lack of invasiveness or exposure of the patient to radiation of other imaging modalities.
Two primary indications for airway POCUS include confirmation of endotracheal intubation and identification of the cricothyroid membrane in the event a surgical airway is required. In this article, the technique of using ultrasound to confirm endotracheal intubation and the relevant anatomy is described, along with the associated ultrasonographic images. In addition, identification of the anatomy of the cricothyroid membrane and the ultrasonographic acquisition of appropriate images to perform this procedure are reviewed.
Future advances include utilizing airway POCUS to identify patient characteristics that might indicate difficult airway management. Traditional bedside clinical exams have, at best, fair predictive values. The addition of ultrasonographic airway assessment has the potential to improve this predictive accuracy. This article describes the use of POCUS for airway management, and initial evidence suggests that this has improved the diagnostic accuracy of predicting a difficult airway. Given that one of the limitations of airway POCUS is that it requires a skilled sonographer, and image analysis can be operator dependent, this paper will provide recommendations to standardize the technical aspects of airway ultrasonography and promote further research utilizing sonography in airway management. The goal of this protocol is to educate researchers and medical health professionals and to advance the research in the field of airway POCUS.

Point of care ultrasound (POCUS) is increasingly being utilized in airway management. Presented here are some clinical utilities of POCUS, including differentiating endotracheal and esophageal intubation, identification of the cricothyroid membrane in the event a surgical airway is required, and measuring anterior neck soft tissue to predict difficult airway management.

With its increasing popularity and accessibility, portable ultrasonography has been rapidly adapted not only to improve the perioperative care of ...

Point-Of-Care Ultrasound Screening for Proximal Lower Extremity Deep Venous Thrombosis

Acute lower extremity deep venous thrombosis (DVT) is a serious vascular disorder that requires accurate and early diagnosis to prevent life-threatening sequelae. While whole leg compression ultrasound with color and spectral Doppler is commonly performed in radiology and vascular labs, point-of-care ultrasound (POCUS) is becoming more common in the acute care setting. Providers appropriately trained in focused POCUS can perform a rapid bedside examination with high sensitivity and specificity in critically ill patients. This paper describes a simplified yet validated approach to POCUS by describing a three-zone protocol for lower extremity DVT POCUS image acquisition. The protocol explains the steps in obtaining vascular images at six compression points in the lower extremity. Beginning at the level of the proximal thigh and moving distally to the popliteal space, the protocol guides the user through each of the compression points in a stepwise manner: from the common femoral vein to the femoral and deep femoral vein bifurcation, and, finally, to the popliteal vein. Further, a visual aid is provided that may assist providers during real-time image acquisition. The goal in presenting this protocol is to help make proximal lower extremity DVT exams more accessible and efficient for POCUS users at the patient&#39;s bedside.

Traditionally, lower extremity deep venous thrombosis (DVT) is diagnosed by radiology-performed venous duplex ultrasound. Providers appropriately trained in focused point-of-care ultrasound (POCUS) can perform a rapid bedside examination with high sensitivity and specificity in critically ill patients. We describe the scanning technique for focused POCUS DVT lower extremity examination.

Acute lower extremity deep venous thrombosis (DVT) is a serious vascular disorder that requires accurate and early diagnosis to prevent life-threatening ...

Troubleshooting FoCUS Image Acquisition: Patient Positioning, Transducer Manipulation, and Image Optimization

Focused cardiac ultrasound (FoCUS) is a limited, clinician-performed application of echocardiography to add real-time information to patient care. These bedside exams are problem oriented, rapidly and repeatedly performed, and largely qualitative in nature. Competency in FoCUS includes mastery of the stereotactic and psychomotor skills required for transducer manipulation and image acquisition. Competency also requires the ability to optimize the setup, troubleshoot image acquisition, and understand the sonographic limitations because of complex clinical environments and patient pathology. This article presents concepts for successful, high-quality two-dimensional (B-mode) image acquisition in FoCUS.
Concepts of high-quality image acquisition can be applied to all established sonographic windows of the FoCUS exam: the parasternal long-axis (PLAX), parasternal short-axis (PSAX), apical four chamber (A4C), subcostal fourchamber (SC4C), and the inferior vena cava (IVC). The apical five-chamber (A5C) and subcostal short-axis (SCSA) views are mentioned, but are not discussed in-depth. A pragmatic figure illustrating the movements of the phased array transducer is also provided to serve as a cognitive aid during FoCUS image acquisition.

Here, we present a protocol to allow providers to perform focused cardiac ultrasound (FoCUS) in the clinical environment. We describe methods of transducer manipulation, review common pitfalls of transducer movements, and suggest tips to optimize phased array transducer use.

Focused cardiac ultrasound (FoCUS) is a limited, clinician-performed application of echocardiography to add real-time information to patient care. These ...

Point-of-Care Lung Ultrasound in Adults: Image Acquisition

Consultative ultrasound performed by radiologists has traditionally not been used for imaging the lungs, as the lungs&#39; air-filled nature normally prevents direct visualization of the lung parenchyma. When showing the lung parenchyma, ultrasound typically generates a number of non-anatomic artifacts. However, over the past several decades, these artifacts have been studied by diagnostic point-of-care ultrasound (POCUS) practitioners, who have identified findings that have value in narrowing the differential diagnoses of cardiopulmonary dysfunction. For instance, in patients presenting with dyspnea, lung POCUS is superior to chest radiography (CXR) for the diagnosis of pneumothorax, pulmonary edema, lung consolidations, and pleural effusions. Despite its known diagnostic value, the utilization of lung POCUS in clinical medicine remains variable, in part because training in this modality across hospitals remains inconsistent. To address this educational gap, this narrative review describes lung POCUS image acquisition in adults, including patient positioning, transducer selection, probe placement, acquisition sequence, and image optimization.

Point-of-care ultrasound (POCUS) of the lungs provides quick answers in rapidly changing clinical scenarios. We present an efficient and informative protocol for image acquisition for use in acute care settings.

Consultative ultrasound performed by radiologists has traditionally not been used for imaging the lungs, as the lungs&#39; air-filled nature normally ...

Point-of-Care Ultrasound: A Review of Ultrasound Parameters for Predicting Difficult Airways

Airway management remains a crucial part of perioperative care. The conventional approach to assessing potentially difficult airways emphasizes the LEMON method, which looks for and evaluates the Mallampati classification, signs of obstruction, and neck mobility. Clinical findings help predict a higher likelihood of difficult tracheal intubation, but no clinical result reliably excludes difficult intubation. Ultrasound as an adjunct to clinical examination can provide the clinician with a dynamic anatomical airway assessment, which is impossible with clinical examination alone. In the hands of anesthesiologists, ultrasound is becoming more popular in the perioperative period. This method is particularly applicable for identifying proper endotracheal tube positioning in specific patient populations, such as those who are morbidly obese and patients with head and neck cancer or trauma. The focus is on identifying the normal anatomy, correctly positioning the endotracheal tube, and refining the parameters that predict difficult intubation. Several ultrasound measurements are clinical indicators of difficult direct laryngoscopy in the literature. A meta-analysis revealed that the distance from the skin to the epiglottis (DSE) is most associated with a difficult laryngoscopy. An ultrasound of the airway could be applied in routine practice as an adjunct to the clinical examination. A full stomach, rapid sequence intubation, gross visual anatomical abnormalities, and restricted neck flexibility prevent using ultrasound to assess the airway. The airway evaluation is performed with a linear array transducer of 12-4 MHz, with the patient in the supine position, with no pillow, and with the head and neck in a neutral position. The central axis of the neck is where the ultrasound parameters are measured. These image acquisitions guide the standard ultrasound examination of the airway.

A point-of-care ultrasound (POCUS) is a simple, non-invasive, and portable tool that enables dynamic airway assessment. Several studies have attempted to determine the role of ultrasound parameters as an adjunct to clinical examination in predicting difficult laryngoscopies.

Airway management remains a crucial part of perioperative care. The conventional approach to assessing potentially difficult airways emphasizes the LEMON ...

A Modified Sonographic Algorithm for Image Acquisition in Life-Threatening Emergencies in the Critically Ill Newborn

The use of routine point-of-care ultrasound (POCUS) is increasing in neonatal intensive care units (NICUs), with several centers advocating for 24 h equipment availability. In 2018, the sonographic algorithm for life-threatening emergencies (SAFE) protocol was published, which allows the assessment of neonates with sudden decompensation to identify abnormal contractility, tamponade, pneumothorax, and pleural effusion. In the study unit (with a consulting neonatal hemodynamics and POCUS service), the algorithm was adapted by including consolidated core steps to support at-risk newborns, aiding clinicians in managing cardiac arrest, and adding views to verify correct intubation. This paper presents a protocol that can be applied in the NICU and the delivery room (DR) in relation to three scenarios: cardiac arrest, hemodynamic deterioration, or respiratory decompensation. 
This protocol can be performed with a state-of-the-art ultrasound machine or an affordable handheld device; the image acquisition protocol is carefully detailed. This method was designed to be learned as a general competence to obtain the timely diagnosis of life-threatening scenarios; the method aims to save time but does not represent a substitute for comprehensive and standardized hemodynamic and radiological analyses by a multidisciplinary team, which might not universally be on call but needs to be involved in the process. From January 2019 to July 2022, in our center, 1,045 hemodynamic consultation/POCUS consults were performed with 25 patients requiring the modified SAFE protocol (2.3%), and a total of 19 procedures were performed. In five cases, trained fellows on call resolved life-threatening situations. Clinical examples are provided that show the importance of including this technique in the care of critical newborns.

Here, we present a protocol that can be applied in the neonatal intensive care unit and the delivery room in relation to three scenarios: cardiac arrest, hemodynamic deterioration, or respiratory decompensation. This protocol can be performed with a state-of-the-art ultrasound machine or an affordable handheld device; an image acquisition protocol is carefully detailed.

The use of routine point-of-care ultrasound (POCUS) is increasing in neonatal intensive care units (NICUs), with several centers advocating for 24 h ...

Imaging the Abdominal Aorta with Point-of-Care Ultrasound

An Approach to Point-Of-Care Ultrasound Evaluation of the Abdominal Aorta

Disorders of the abdominal aorta, including aneurysms and dissection, have potentially high rates of morbidity and mortality. While computed tomography (CT) is the current gold standard to image the abdominal aorta, the process of obtaining a CT may be time-consuming, requires the use of intravenous contrast dye, and involves exposure to ionizing radiation. Point-of-care Ultrasound (POCUS) can be performed at the bedside and has excellent sensitivity and specificity for the diagnosis of abdominal aortic aneurysm and excellent specificity for the diagnosis of abdominal aortic dissection. Additionally, POCUS is non-invasive, cost-effective, lacks ionizing radiation, requires no intravenous contrast dye, and can be performed without taking the patient from a critical care area. Screening for abdominal aortic aneurysm (AAA) can be done in primary care settings as well. 
This article will review the approach to POCUS of the abdominal aorta to evaluate such critical pathology. In this paper, we will review the sonographic anatomy of the abdominal aorta as well as the choice of the ultrasound probe, description of POCUS image acquisition, and some pearls and pitfalls of using POCUS to aid in the diagnosis of potentially life-threatening abdominal aortic pathology.

Author Spotlight: Using Point-of-Care Ultrasound for Comprehensive Evaluation of the Abdominal Aorta

This protocol reviews the steps to image the abdominal aorta with point-of-care ultrasound. We discuss image acquisition, troubleshooting imaging pitfalls and artifacts, and the recognition of life-threatening abdominal aortic pathology.

Disorders of the abdominal aorta, including aneurysms and dissection, have potentially high rates of morbidity and mortality. While computed tomography ...

Gastric Ultrasound Technique for Mitigating Peri-Procedural Aspiration Risk

Gastric Point of Care Ultrasound in Adults: Image Acquisition and Interpretation

Over the past two decades, diagnostic point-of-care ultrasound (POCUS) has emerged as a rapid and non-invasive bedside tool for addressing clinical inquiries related to gastric content. One emerging concern pertains to patients about to undergo sedation and/or endotracheal intubation: the elevated risk of aspiration from the patient&#39;s stomach contents. Aspiration of gastric contents into the lungs poses a serious and potentially life-threatening complication. This occurs more frequently when the stomach is considered &#34;full&#34; and can be affected by the techniques employed for airway management, making it potentially preventable. To mitigate the risk of peri-procedural aspiration, two distinct medical specialties (anesthesiology and critical care medicine) have independently developed techniques to utilize ultrasonography for identifying patients requiring &#34;full stomach&#34; precautions. Due to these separate specialties, the work of each group remains relatively unfamiliar outside its respective field. This article presents descriptions of both techniques for gastric ultrasound. Furthermore, it explains how these approaches can complement each other when one of them falls short. Regarding image acquisition, the article covers the following topics: indications and contraindications, selection of the appropriate probe, patient positioning, and troubleshooting. The article also delves into image interpretation, complete with example images. Additionally, it demonstrates how one of the two techniques can be employed to estimate gastric fluid volume. Lastly, the article briefly discusses medical decision-making based on the findings of this examination.

Author Spotlight: Point-of-Care Ultrasound for Gastric Content Assessment and Risk Stratification in Perioperative Care 

This protocol introduces two methods for image acquisition in gastric ultrasonography. Additionally, tips are provided for interpreting this information to assist in medical decision-making.

Over the past two decades, diagnostic point-of-care ultrasound (POCUS) has emerged as a rapid and non-invasive bedside tool for addressing clinical ...

Ultrasound in Evaluating Diaphragm Dysfunction and Monitoring Treatment

Measuring Diaphragm Thickness and Function Using Point-of-Care Ultrasound

The diaphragm is the main component of the respiratory muscle pump. Diaphragm dysfunction can cause dyspnea and exercise intolerance, and predisposes affected individuals to respiratory failure. In mechanically ventilated patients, the diaphragm is susceptible to atrophy and dysfunction through disuse and other mechanisms. This contributes to failure to wean and poor long-term clinical outcomes. Point-of-care ultrasound provides a valid and reproducible method for evaluating diaphragm thickness and contractile activity (thickening fraction during inspiration) that can be readily employed by clinicians and researchers alike. This article presents best practices for measuring diaphragm thickness and quantifying diaphragm thickening during tidal breathing or maximal inspiration. Once mastered, this technique can be used to diagnose and prognosticate diaphragm dysfunction, and guide and monitor response to treatment over time in both healthy individuals and acute or chronically ill patients.

Author Spotlight: Unraveling the Impact of Mechanical Ventilation on Diaphragm Function and Patient Outcomes 

Diaphragm thickness and function can be assessed in healthy individuals and critically ill patients using point-of-care ultrasound. This technique offers an accurate, reproducible, feasible, and well-tolerated method for evaluating diaphragm structure and function.

The diaphragm is the main component of the respiratory muscle pump. Diaphragm dysfunction can cause dyspnea and exercise intolerance, and predisposes ...

Probe Selection and Machine Presets for Point-of-Care Ultrasound of the Abdominal Aorta

To perform a point of care ultrasound evaluation of the abdominal aorta, select a 2.5 to 3.5 megahertz curvilinear probe, which provides the best visualization for most adults. Alternatively, use the phased array probe of 1 to 5 megahertz, commonly called cardiac probe, which is typically used for echocardiography. Use the abdominal preset on the machine regardless of the probe used.Set the mode to B mode or two-dimensional gray scale and the depth to 20 centimeters. Adjust the depth once the aorta is visualized to keep the aorta in the midfield of the screen. Choose a lower frequency range for patients with a high body mass index to improve image acquisition.