ARTICLE IN PRESSJournal of Cardiothoracic and Vascular Anesthesia 000 (2021) 1�16

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Review Article

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https://doi.org/10.105

1053-0770/� 2021 Th

Point-of-Care Ultrasound (POCUS) for the

Cardiothoracic Anesthesiologist

Hari Kalagara, MD*, Bradley Coker, MD*,Neal S. Gerstein, MD, FASEy, Promil Kukreja, MD, PhD*,

Lev Deriy, MDy, Albert Pierce, MD*,Matthew M. Townsley, MD, FASE*,1

*Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham,

Birmingham, ALyDepartment of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine,

Albuquerque, NM

Point-of-Care Ultrasound (POCUS) is a valuable bedside diagnostic tool for a variety of expeditious clinical assessments or as guidance for a

multitude of acute care procedures. Varying aspects of nearly all organ systems can be evaluated using POCUS and, with the increasing avail-

ability of affordable ultrasound systems over the past decade, many now refer to POCUS as the 21st-century stethoscope. With the current avail-

able and growing evidence for the clinical value of POCUS, its utility across the perioperative arena adds enormous benefit to clinical decision-

making.

Cardiothoracic anesthesiologists routinely have used portable ultrasound systems for nearly as long as the technology has been available, mak-

ing POCUS applications a natural extension of existing cardiothoracic anesthesia practice. This narrative review presents a broad discussion of

the utility of POCUS for the cardiothoracic anesthesiologist in varying perioperative contexts, including the preoperative clinic, the operating

room (OR), intensive care unit (ICU), and others. Furthermore, POCUS-related education, competence, and certification are addressed.

� 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license

(http://creativecommons.org/licenses/by/4.0/)

Keywords: Point-of-Care Ultrasound; lung ultrasound; transthoracic echocardiography; airway ultrasound; gastric ultrasound; ultrasound education

POINT-OF-CARE ULTRASOUND (POCUS) is the use of

portable bedside ultrasound imaging for a variety of expedi-

tious clinical assessments or as guidance for a multitude of

acute care procedures. With the increasing availability of

affordable ultrasound systems over the past decade, POCUS

use has burgeoned over a similar time frame, with low-cost

portable systems now considered the 21st-century stetho-

scope.1,2 Ideally, POCUS use in clinical management should

be goal-directed, rapid, and reproducible. Varying aspects of

nearly all organ systems can be evaluated using POCUS (see

Table 1), and there are increasingly more clinical conditions

ence to Matthew M. Townsley, MD, FASE, 619 South

ngham, AL 35249-6810.

townsley@uabmc.edu (M.M. Townsley).

3/j.jvca.2021.01.018

e Authors. Published by Elsevier Inc. This is an open access a

in which the utilization of POCUS may have a role.3,4 In par-

ticular, this growth has been accelerated further with the

availability and accessibility of small handheld ultrasound

devices. In certain clinical contexts (eg, pneumothorax

[PTX], hemidiaphragmatic paresis), POCUS has superior

diagnostic sensitivity and specificity compared to other diag-

nostic modalities, while also mitigating the higher costs and

possible radiation side effects of non-ultrasound imaging.5

Various medical societies (eg, Society of Critical Care Medi-

cine, American Society of Echocardiography) have devel-

oped POCUS guidelines for its usage across a wide range of

clinical settings.6,7

Cardiothoracic anesthesiologists routinely have used porta-

ble ultrasound systems for nearly as long as the technology has

been available, particularly as a tool to guide vascular access

rticle under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Table 1

Common Point-of-Care Ultrasound (POCUS) Applications

POCUS Structures Utility

Airway CTM, trachea Cricothyroidotomy,

endotracheal intubation

Breathing (lung) Pleura, lung, diaphragm Pneumothorax, lung

parenchymal disease,

pleural effusion,

pulmonary edema

Circulation (cardiac) LV, RV, cardiac valves Myocardial ischemia,

CHF, valvular lesions

Pericardium Tamponade

Aorta & aortic arch Aneurysm and dissection

Gastric Antrum Gastric volume and

contents

Vascular Veins Central and peripheral

venous cannulation

Arteries Invasive monitoring,

IABP

IVC Volume status

VExUS scan Fluid overload

Deep veins DVT

Abbreviations: CHF, congestive heart failure; CTM, cricothyroid membrane;

DVT, deep vein thrombosis; IABP, intra-aortic balloon pump; IVC, inferior

vena cava; LV, left ventricle; POCUS, point-of-care ultrasound; RV, right

ventricle; VExUS scan, venous excess ultrasound scan.

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2 H. Kalagara et al. / Journal of Cardiothoracic and Vascular Anesthesia 00 (2021) 1�16

procedures and for echocardiographic applications. Since

transesophageal echocardiography (TEE) is used routinely by

most cardiothoracic anesthesiologists, POCUS applications

are a natural extension of existing practice.8,9 This narrative

review presents a broad discussion of the utility of POCUS for

the cardiothoracic anesthesiologist in varying perioperative

contexts, including the preoperative clinic, the operating room

(OR), and intensive care unit (ICU). Furthermore, POCUS-

related education, competence, and certification are addressed.

Airway Ultrasound (AUS)

POCUS of the airway is useful for identification of airway

structures, such as the cricothyroid membrane (CTM), tracheal

rings, cricoid cartilage, thyroid cartilage, and hyoid bone (see

Table 2).10 In difficult airway scenarios, identification of the

CTM by AUS has been shown to be useful for cricothyroidot-

omy procedures (see Fig 1). Kristensen et al. demonstrated

that the identification of the CTM by ultrasound had a higher

Table 2

Overview of Airway Ultrasound (AUS)

POCUS Structures Techniques

Airway CTM Cricothyroidotomy

Cricoid cartilage Cricoid pressure for RSI

Thyroid cartilage Airway blocks

Hyoid bone Airway assessment

Tracheal rings Percutaneous tracheostomy

Esophagus Endotracheal/esophageal intubation

Abbreviations: CTM, cricothyroid membrane; POCUS, point-of-care

ultrasound; RSI, rapid-sequence intubation.

success rate than traditional inspection and palpation meth-

ods.11,12 The utilization of ultrasound for preprocedural identi-

fication of tracheal rings, as well as pre- and paratracheal

anatomy and blood vessels (especially abnormal vasculature),

is helpful in assisting with the correct location and safe place-

ment of a percutaneous tracheostomy.13,14 AUS also is useful

for performing airways blocks to facilitate awake fiberoptic

intubations, improving airway and intubating conditions com-

pared to blind tecnhiques.15,16

AUS also has shown utility in confirming correct endotra-

cheal tube placement and in discerning between esophageal

and endotracheal intubation. With endotracheal intubation, a

single bullet sign (single air-mucosal interface with increased

posterior artifact shadowing) will be visualized, along with the

presence of bilateral lung sliding. Esophageal intubation has a

unique double-tract sign appearance and absence of bilateral

lung sliding. In a systematic review by Das et al., the authors

found that AUS had a pooled sensitivity of 0.98 (95% CI,

0.97-0.99) and pooled specificity of 0.98 (95% CI, 0.95-0.99)

in confirming endotracheal intubation.17 A meta-analysis by

Gottlieb et al., which included 17 studies and a total of 1,595

patients, showed transtracheal ultrasonography was 98.7%

sensitive (95% CI, 97.8-99.2) and 97.1% specific (95% CI,

92.4-99.0) in confirming endotracheal intubation, with a mean

time to confirmation of 13 seconds (95% CI, 12.0-14.0).18

AUS is a valuable and reliable adjunct for endotracheal intuba-

tion in cardiac arrest situations in which the end-tidal CO2 is

low.19,20 AUS has been described for the prediction and

assessment of difficult airways and evaluation of the epiglottis

and vocal cords.21,22 Skin-hyoid distance is known to predict

difficult mask ventilation and difficult laryngoscopy, while the

epiglottis-to-vocal cord space has been shown to correlate

with Cormack-Lehane intubation grade.23,24 Specifically, the

mean standard deviation of the minimum distance from the

hyoid bone to skin surface was 0.88 (0.3) cm in the easy mask

ventilation group versus 1.4 (0.19) cm in the difficult mask

ventilation group. The mean of this distance increased accord-

ing to the level of difficulty of mask ventilation and laryngos-

copy. The distance of the epiglottis to the vocal cord space

was found to be a better predictor of difficult laryngoscopy

compared to the hyomental distance ratio. A distance from the

epiglottis to vocal cords of more than 1.77 cm had 82%

Fig 1. Ultrasound (US)-guided airway examination to identify the cricothy-

roid membrane (CTM). The image on the left demonstrates probe positioning

for the performance of a US-guided airway examination, while the image on

the right illustrates key anatomy seen in the airway US examination.

Table 3

Overview of Gastric Ultrasound (GUS)

POCUS Structures Assessment Aspiration Risk

Gastric Gastric antrum Gastric volume Low risk (<1.5 mL/

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H. Kalagara et al. / Journal of Cardiothoracic and Vascular Anesthesia 00 (2021) 1�16 3

sensitivity and 80% specificity in predicting difficult laryngos-

copy, whereas a hyomental distance ratio less than 1.085 had a

sensitivity of 75% and specificity of 85.3% in this prediction.

Additionally, AUS can be used for the application of cricoid

pressure during rapid-sequence induction.25

Gastric contents

(liquids or solids)

kg)

High risk (>1.5

mL/kg)

High risk (solid)

Abbreviations: POCUS, point-of-care ultrasound.

Gastric Ultrasound (GUS)

Perioperative aspiration prevention is an important consid-

eration during any surgical or interventional procedure, as

aspiration of gastric contents may lead to aspiration pneumo-

nia, which is associated with high morbidity and mortality.26

Evaluation of fasting status or assuring adequate gastric emp-

tying has occurred can be challenging in numerous circum-

stances, such as patients with altered mental status and those

with certain chronic medical conditions (eg, gastroparesis, dia-

betes, or chronic renal failure and liver failure). Aspiration risk

is particularly extant in the context of procedures performed

with moderate or deep sedation without an ETT (ie, out-of-

operating room transesophageal echocardiograph [TEE]

examinations). GUS allows for the identification and measure-

ment of gastric antral cross-sectional area, with accurate

assessment of gastric volume and contents in both the supine

and right lateral decubitus positions.27,28 Figure 2 illustrates

probe placement and imaging of the gastric antrum.

A randomized control trial by Kruisselbrink et al., using

simulated clinical scenarios in nonpregnant adults with a pre-

test probability of 50% full stomach, showed that bedside

GUS had a sensitivity of 1.0 (95% CI, 0.925-1.0), a specificity

of 0.975 (95% CI, 0-0.072), a positive predictive value of

0.976 (95% CI, 0.878-1.0), and a negative predictive value of

1.0 (95% CI, 0.92-1.0) in ruling out a full stomach in patients

in whom the presence of gastric contents was ambiguous.29

Using nomogram-based data derived from measured antral

cross-sectional area and patient age, gastric volume can be pre-

dicted (see Table 3) by GUS.30 In summary, GUS can be per-

formed easily at the bedside to provide qualitative and

quantitative assessment of gastric contents, aiding in the for-

mulation of a safe anesthetic airway management plan to mini-

mize aspiration risk.31 However, there are currently no major

society recommendations to replace nothing -by-mouth guide-

lines with gastric ultrasound.

Fig 2. Ultrasound (US)-guided gastric scan to assess gastric volume and con-

tent. The image on the left demonstrates probe positioning for the performance

of an US-guided gastric examination, while the image on the right illustrates

key anatomy seen in the gastric US examination.

Lung Ultrasound (LUS)

Lung ultrasound (LUS) (see Table 4) involves the study of

air-fluid interfaces in the lungs, as well as the interpretation of

ultrasound artifacts.32 Different transducers, such as phased-

array, convex, microconvex, or linear probes, are being used

for LUS to optimize the artifacts based on the lung pathology

to be determined and the patient’s body habitus.33 Longitudi-

nal scanning is performed in six or eight zones for focused

lung examinations, with transverse scanning recommended in

areas of specific interest for further evaluation of pathology.34

POCUS of the lung is indicated to evaluate dyspnea, hypoxia,

hypotension, thoracic trauma, pleurisy, and chest pain.35 Inter-

national evidence-based consensus recommendations for

point-of-care lung ultrasound from Volpicelli et al. have

proven helpful in guiding the implementation, development,

and standardization of LUS across a variety of clinical set-

tings.36 Figure 3 outlines a decision-making algorithm to guide

the assessment of lung pathology with LUS.

Normal LUS Mechanics

Normal lung aeration is characterized by lung sliding,

described as movement of the parietal and visceral pleura slid-

ing against each other at the pleural line (equivalent to a sea-

shore sign on the M-mode Doppler evaluations), as demon-

strated by Video 1. Normal lung parenchyma will have an A

profile pattern, seen as regular, repetitive horizontal reverbera-

tion artifacts arising from air below the pleural line (Fig 4).

When air is replaced with fluid, the image will show B lines,

which are comet-tail artifacts (vertical hyperechoic lines

Table 4

Overview of Lung Ultrasound (LUS)

POCUS Structure Assessment Disease

Lungs (LUS) Pleura Lung sliding Pneumothorax

Lung zones A and B lines Pneumonia, ARDS,

pulmonary edema

PLAPS point Lung bases Pleural effusion,

pneumonia

Diaphragm Diaphragm function Weaning/ventilation,

diaphragmatic

paresis/paralysis

Abbreviations: ARDS, acute respiratory distress syndrome; PLAPS, posterior

lateral alveolar pleural syndrome; POCUS, point-of-care ultrasound.

Fig 3. Decision algorithm for guiding the assessment of lung pathology using

LUS. LUS, lung ultrasound; DVT, deep vein thrombosis; PLAPS, posterior

lateral alveolar pleural syndrome.

Fig 4. Normal lung ultrasound (LUS) images and A lines. Panel A demon-

strates probe positioning for evaluation of ribs and pleura, while panel B dem-

onstrates ultrasound visualization of these structures. Panels C and D

demonstrate probe positioning and visualization of A lines, respectively.

Fig 5. Lung point. The presence of lung point, defined as the appearance and

disappearance of lung sliding with respiration at a particular point, is charac-

teristic and pathognomonic for pneumothorax.

Fig 6. Algorithm aiding the diagnosis and exclusion of pneumothorax using

lung ultrasound (LUS). PTX, pneumothorax.

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arising from the pleural line and fanning down all the way to

the bottom of the screen) demonstrated by Video 2.

Abnormal LUS Mechanics

When the ratio of fluid-to-air content increases, the number

of B lines increases in lung zones accordingly, resulting in a B

profile pattern. The presence of B lines rules out PTX.37 Inter-

stitial lung disease and pulmonary edema may be indicated by

the number and distribution of B lines (lung rockets) in each

zone (three or fewer in each lung zone is seen in a healthy

lung). Absence of lung sliding in a particular lung zone should

raise suspicion for PTX. The presence of lung point, defined as

the appearance and disappearance of lung sliding with respira-

tion at a particular point (equivalent to the M-mode strato-

sphere or barcode sign), is characteristic and pathognomonic

for PTX, with a reported overall sensitivity of 66% and a spec-

ificity of 100% for the diagnosis of PTX.37,38 Lung point is

demonstrated in Video 3 and Figure 5, while an algorithm

guiding the diagnosis and exclusion of PTX using LUS is illus-

trated in Figure 6.

The posterior lateral alveolar pleural syndrome (PLAPS)

point is the lowest point in the lung that should be investigated

with a curvilinear probe to rule out pleural effusion and con-

solidation.39 The detection of PLAPS point indicates

consolidation or effusion at the lung bases, while absence of

PLAPS point suggests other pathology at the lung bases. Nor-

mally, the spine above the diaphragm is not visible. However,

if pleural effusion is present, the spine is visible through the

fluid and is referred to as "spine sign". With a normally aerated

lung, the lung moves downward into the abdomen with inspi-

ration (curtain sign). In the presence of pleural effusion, this

curtain sign is absent. Dynamic air bronchograms signify con-

solidation, while static air bronchograms indicate atelectasis.

A meta-analysis comparing the accuracy of LUS and chest X-

ray (CXR) indicated that LUS had a higher pooled sensitivity

(0.95; 95% CI, 0.93-0.97) and specificity (0.90; 95% CI, 0.86-

0.94) with better diagnostic accuracy compared to CXR in aid-

ing the diagnosis of community-acquired pneumonia (using

chest-computed tomography as the gold standard).40

LUS Versus Other Imaging Modalities

LUS offers unique advantages over computed tomography,

as it is portable, reproducible, low cost, low risk, and highly

accurate, and possesses no radiation effects. As previously

Fig 7. Panel A depicts a supine patient position with the ultrasound (US)

probe placed along the midaxillary line. Panel B shows a US image of the dia-

phragm during inspiration (measuring diaphragm thickness of 0.25 cm).

Table 5

Diagnosis of Lung Disease Based on Lung Ultrasound (LUS)

Diagnosis Present on LUS Absent on LUS FOCUS

PTX Lung point

Barcode or stratosphere sign (M mode LUS)

Lung sliding, B lines, Lung pulse

PNA B lines, air bronchograms, PLAPS Lung sliding

CHF Bilateral B lines, lung sliding Reduced FS, EF, and EPSS

ARDS B lines, lung sliding Normal EF and EPSS

Pulmonary fibrosis B lines Lung sliding

COPD/asthma Lung sliding, A lines B lines, PLAPS

Pleural effusion Anechoic lung base, air bronchograms, spine sign Curtain sign Reduced EF in CHF

Pulmonary embolism Lung sliding, A lines Reduced TAPSE, reduced RV function,

Diaphragmatic paresis Reduced diaphragm excursion and thickness

Abbreviations: ARDS, acute respiratory distress syndrome; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; EF, ejection fraction;

EPSS, endpoint (mitral) septal separation; FOCUS, Focused Cardiac Ultrasound; FS, fractional shortening; LUS, lung ultrasound; PLAPS, posterior lateral

alveolar pleural syndrome; PNA, pneumonia; PTX, pneumothorax; RV, right ventricle; TAPSE, tricuspid annular plane systolic excursion.

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H. Kalagara et al. / Journal of Cardiothoracic and Vascular Anesthesia 00 (2021) 1�16 5

described, LUS can be used to diagnose PTX, with better sen-

sitivity and specificity compared to CXR.41 A meta-analysis

by Ding et al. indicated that LUS had a higher pooled sensitiv-

ity (0.88) compared to CXR (0.52), and similar specificity, in

the diagnosis of PTX.42 Notably, the accuracy of diagnosing

PTX with LUS is associated with the skill of the operator

(odds ratio, 0.21; CI, 0.05-0.96; p = 0.0455). Chan et al., in a

recent Cochrane Database systematic review examining LUS

versus CXR for the diagnosis of PTX in trauma patients,

reported a sensitivity of 0.91 (95% CI, 0.85-0.94) and specific-

ity of 0.99 (95% CI, 0.97-1.00) for LUS, compared to a sensi-

tivity of 0.47 (95% CI, 0.31-0.63) for CXR.43 This review

suggested the superior diagnostic accuracy of LUS versus

CXR for PTX diagnosis.

LUS also is efficacious in the diagnosis of pulmonary

edema.44 Maw et al. established that LUS is more sensitive

(0.88 [95% CI, 0.75-0.95]) than CXR (0.73 [95% CI, 0.70-

0.76]) in the detection of pulmonary edema in patients with

decompensated heart failure. The relative sensitivity ratio of

LUS compared to CXR was 1.2 (95% CI, 1.08-1.34; p <

0.001), proposing LUS as a useful adjunct modality in the

evaluation of patients with heart failure.44 A meta-analysis by

Al Deeb et al. demonstrated the sensitivity of LUS B lines to

diagnose pulmonary edema as 94.1% (95% CI, 81.3-98.3),

with a specificity of 92.4% (95% CI, 84.2-96.4%).45 Similarly,

Platz et al. demonstrated the utility of B lines with LUS for

prognostic purposes of heart failure therapy.46

LUS is efficacious in the diagnosis of lung parenchymal dis-

eases,40 while enabling a better understanding of heart-lung

interactions to assist in ventilatory management.47-50 LUS also

can be used for confirmation of double-lumen tube placement

during lung isolation maneuvers.51,52 Lichtenstein et al. incor-

porated LUS into their bedside lung ultrasound in emergency

(BLUE) protocol for the diagnosis of acute respiratory fail-

ure,39,53 and FALLS (fluid administration limited by LUS)

protocol for the management of acute circulatory failure.53,54

Table 5 highlights the diagnostic utility of LUS signs, along

with focused cardiac ultrasound, to help differentiate various

lung diseases.

Diaphragm Ultrasound (DUS)

The diaphragm is the core muscle of respiration, innervated

by the phrenic nerve and normally descending caudally and

increasing in thickness with inspiration. In cases of respiratory

distress, LUS, along with DUS assessment, are useful to rule

out potential etiologies such as PTX and diaphragmatic paraly-

sis (ie, post-brachial plexus blockade). Diaphragmatic excur-

sion during deep breathing (normally 6-7 cm) typically is

assessed by Doppler M-mode, but may be challenging at times

on the left side due to air in the stomach. A novel intercostal

approach that assesses the zone of apposition of the diaphragm

can be used to overcome this issue (see Fig 7). The intercostal

zone of apposition approach is used to measure diaphragm

thickness during inspiration and expiration. The thickening

fraction then is calculated, which can be used to quantify the

degree of paresis.55 This thickening fraction is useful for venti-

latory management and in guiding the process of weaning ven-

tilatory support in critically ill patients (normal thickening

fraction is 30%-96%). DUS possesses utility in the prediction

of extubation success by monitoring respiratory load, with

Table 7

Advanced Modalities With Focused Cardiac Ultrasound (FOCUS)

2D View Abnormal Values Disease

LA

Aorta

RV

PLAX

PLAX

PLAX, PSAX,

A4C, SC4C

Increased

Increased

Increased

Dilated LA

Aortic aneurysm

RVH, RVF, PE

M mode

FS and EF

EPSS

TAPSE

MAPSE

PLAX and PSAX

PLAX

A4C

A4C

Decreased

Decreased

Decreased

Decreased

CHF

CHF

RVF

LVF

Diastology

E/A

e’

E/e’ (LVEDP)

A4C

A4C

A4C

Increased

Decreased

Increased

Elevated LAP

Diastolic

dysfunction

Diastolic

dysfunction

CFD/CWD/PWD

RVSP

LVOT VTI

(SV, CO)

RVOT VTI

A4C

PLAX, A5C

PSAX

Increased

Decreased

Decreased

PHTN

LVF

RVF

Abbreviations: A4C, apical four-chamber; A5C, apical five-chamber; CFD,

color-flow Doppler; CHF, congestive heart failure; CO, cardiac output; CWD,

continuous-wave Doppler; EF, ejection fraction; EPSS, endpoint septal

separation; FS, fractional shortening; IVC, inferior vena cava; LA, left atrium;

LAP, left atrial pressure; LV, left ventricle; LVEDP, left ventricular end-

diastolic pressure; LVF, left ventricular failure; LVOT VTI, left ventricular

outflow tract velocity-time integral; MAPSE, mitral annular plane systolic

excursion; PE, pulmonary embolism; PHTN, pulmonary hypertension; PLAX,

parasternal long-axis; PSAX, parasternal short axis; PWD, pulsed-wave

Doppler; RV, right ventricle; RVF, right ventricular failure; RVH, right

ventricular hypertrophy; RVOT VTI, right ventricular outflow tract velocity-

time integral; RVSP, right ventricular systolic pressure; SC4C, subcostal four-

chamber; SV, stroke volume; TAPSE, tricuspid annular plane systolic

excursion.

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optimal cutoffs greater than 30% to 36% for thickening frac-

tion, serving as a beneficial tool in detecting diaphragmatic

dysfunction.56

Focused Cardiac Ultrasound (FOCUS)

In hemodynamically unstable patients, a focused transtho-

racic echocardiographic (TTE) examination (FOCUS) is useful

to evaluate global and regional left and right ventricular func-

tion, assess for valvular dysfunction, and identify the presence

of any hemodynamically significant pericardial effusions.57

Specific cardiac pathology easily recognized with a FOCUS

examination includes aortic stenosis (see Video 4), dilated car-

diomyopathy (see Video 5), pericardial tamponade (see Video

6), hypertrophic obstructive cardiomyopathy with dynamic

left ventricular outflow tract obstruction (see Video 7), endo-

carditis (see Video 8), and pulmonary embolism (see Video 9).

Practice advisory guidelines for the appropriate use of bedside

cardiac ultrasonography in the evaluation of critically ill

patients, as well as grading recommendations regarding

FOCUS usage for various cardiac pathologies, chest trauma,

and diseases of the great vessels, are readily available.58,59

FOCUS most commonly is performed with a low-frequency

cardiac phased-array probe, with patients typically placed in

supine or left lateral position to best optimize imaging and

acoustic windows.60,61 Basic FOCUS views can be used for

assessment of cardiac pathology (see Table 6), as well as quan-

titative assessments of cardiac function (see Table 7). Via et al.

have published international evidence-based recommenda-

tions, delineating the nature, technique, benefits, clinical inte-

gration, education, and certification in FOCUS to offer a

framework for applying FOCUS applications across different

clinical settings around the world.62

Table 6

Overview of Focused Cardiac Ultrasound (FOCUS)

FOCUS View Assessment Clinical Indication Pathology

PLAX LV, RV, LA, aorta

AV and MV

Function, valves,

effusion

MI, CHF, AS,

HOCM

PSAX LV, RV

Pericardium

Function, effusion Ischemia,

hypovolemia,

Tamponade

A4C RA, RV, LA, LV

TV, MV, AV

Function, valves,

effusion

PE, MI,

cardiomyopathy, Tamponade, HOCM

CHF, RVF, PHTNSC4CRA, RV, LA, LVFunction, valves, effusionPE,

hypovolemia, TamponadeSC IVCIVCVolume statusHypovolemia

Fluid overloadSS viewAortic arch and branchesAortic lesions

IABPAortic dissection

Coarctation of aorta

Abbreviations: A4C, apical four-chamber; AS, aortic stenosis; AV, aortic

valve; CHF, congestive heart failure; HOCM, hypertrophic obstructive

cardiomyopathy; IABP, intra-aortic balloon pump; IVC, inferior vena cava;

LA, let atrium; LV, left ventricle; MI, myocardial infarction; MV, mitral

valve; PE, pulmonary embolism; PHTN, pulmonary hypertension; PLAX,

parasternal long-axis; PSAX, parasternal short axis; RA, right atrium; RV,

right ventricle; RVF, right ventricular failure; SC4C, subcostal 4-chamber; SS,

suprasternal; TV, tricuspid valve.

Hemodynamic perturbations and unexplained hypotension

are extremely common issues encountered in the perioperative

setting, with FOCUS being a useful tool for determining the

etiology of unexplained hemodynamic instability, as well as

for guiding clinical management and interventions. FOCUS is

particularly helpful in detecting right ventricular dysfunction

and regional wall motion abnormalities following ischemia in

patients presenting with acute coronary syndromes.63,64

When FOCUS is used to answer a specific clinical question

(eg, investigation of newly discovered systolic murmur or to

determine the underlying etiology of unexplained hemody-

namic instability or decreased functional capacity), its use has

a significant impact on perioperative care (eg, altered anes-

thetic technique, prompted decision to perform invasive moni-

toring, or led to a change postoperative care disposition) in up

to 82% of patients.65 In the aforementioned study, major find-

ings from anesthesiologist-performed FOCUS examinations

(ie, significant valvular lesions) were confirmed subsequently

by cardiology evaluation in 92% of patients. Massive pulmo-

nary embolism and cardiac tamponade are potentially devast-

ing perioperative complications in which FOCUS provides

rapid diagnostic confirmation to guide immediate lifesaving

Table 8

Vascular Ultrasound Applications

Modality Structures Procedures/Assessments

Vascular access IJ, subclavian, and

femoral veins

Radial, brachial, and

femoral arteries

Peripheral veins

Central lines

Arterial lines

PIVs

Volume assessment IVC

Common carotid artery

Common femoral vein

CVP, RAP

CFT, carotid VTI

Pulsatility (RV

function)

VExUS IVC (transverse view)

Hepatic vein

Portal vein

Renal vein

VExUS score for fluid

overload

Venous scan Lower extremity veins DVT

Abbreviations: CFT, corrected flow time; CVP, central venous pressure; DVT,

deep vein thrombosis; IJ, internal jugular; IVC, inferior vena cava; PIVs,

peripheral intravenous lines; RAP, right atrial pressure; RV, right ventricle;

VExUS scan, venous excess ultrasound scan; VTI, velocity-time integral.

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treatments. Valvular stenosis, valvular regurgitation, left and

right ventricular dysfunction, cardiac masses, and cardiomyop-

athies (ie, hypertrophic cardiomyopathy, dilated cardiomyopa-

thy) can be assessed quickly and, where relevant, quantified

with a FOCUS examination.66

FOCUS also is emerging as a valuable tool in the diagnosis

and management of cardiac arrest. The Focused Echocardio-

graphic Examination in Life protocol describes FOCUS usage

during performance of advanced cardiac life support (ACLS)

protocols.67,68 Importantly, FOCUS can be incorporated into

the performance of ACLS without interrupting performance of

standard chest compressions, with subcostal views best facili-

tating this indication. Adequate images may be obtained dur-

ing brief (ie, ten-second) periods when compressions are

interrupted to assess for underlying cardiac rhythm and pulse.

The presence of underlying cardiac activity by FOCUS assess-

ment during ACLS has been associated with improved survival

following return of spontaneous circulation.69 The use of

FOCUS in this setting also enables clinicians to diagnose

potentially treatable and reversible causes (eg, pulmonary

embolism, tamponade, or severe left ventricular dysfunction)

and to guide further therapeutic interventions.

Table 9

Simplified Venous Excess Ultrasound (VExUS) Scoring System

Organ system VExUS = 0

(No Congestion)

VExUS = 1

IVC IVC < 2 cm IVC > 2 cm

Hepatic vein

Doppler

Normal pattern Normal

(S > D)

Portal vein

Doppler

Normal pattern Normal

(<30% pulsatility index)

Renal vein

Doppler

Normal pattern Normal

(continuous monophasic flow)

NOTE. Adapted from: Beaubien-Souligny et al.74

Abbreviations: D, diastolic wave; IVC, inferior vena cava; S, systolic wave; VExUS

Vascular Ultrasound (VUS)

VUS (see Table 8) with a linear probe commonly is used for

the placement of central venous, arterial, and peripheral intra-

venous catheters. Furthermore, FOCUS examination aids in

assessing volume status, as central venous pressure or right

atrial pressure estimations (performed using the subcostal infe-

rior vena cava [IVC] view), can be obtained by measuring

IVC diameter, respiratory variation, and collapsibility index.70

A meta-analysis evaluating the utility of using measurements

of IVC diameter and respiratory variation to predict fluid

responsiveness found the modality more sensitive and specific

in mechanically ventilated patients compared to spontaneously

breathing patients.71 Other modalities, such as carotid Dopp-

ler, can be used for hemodynamic assessments.72,73 Using

POCUS to assess change in carotid flow time is an acceptable

method for noninvasive assessment of fluid responsiveness in

shock states, and also can act as a surrogate for cardiac output.

If the IVC transverse diameter is more than 2 cm, the use of

combined hepatic vein, portal vein, and renal vein pulsed-

wave Doppler assessments, as a part of venous excess ultra-

sound (VExUS) scan, can be done to evaluate for volume over-

load and systemic venous congestion. Beaubien-Souligny et al.

described a VExUS scoring system (see Table 9) to quantify

systemic congestion and its impact on renal dysfunction in

post-cardiac surgery patients.74-76 The severity of the VExUS

score is used as a guide for fluids, inotropes, vasodilators, and

diuretic management. Measurement of the right ventricular

outflow tract velocity-time integral with FOCUS, when com-

bined with the VExUS scan, enables a global evaluation of

right ventricular function and, when dysfunction is present, its

effects on systemic organ congestion.

Additionally, evaluation for the presence of lower-extremity

deep vein thrombosis (DVT) is a core part of the POCUS

examination, especially in critically ill patients. A comprehen-

sive scan should begin with visualization of the common fem-

oral vein. Subsequently, all five major points of vascular

bifurcation within the lower-extremity veins are identified,

with a two-point compression test performed at each point to

rule out DVT.77,78 A systematic review assessing the accuracy

of emergency physician-performed ultrasound found a sensi-

tivity of 96.1% and specificity of 96.8% for the diagnosis of

DVT.79 Also, positive findings from the VUS DVT scan, when

VExUS = 2 VExUS = 3

(Severe Congestion)

IVC > 2 cm IVC > 2 cm

Mild abnormality

(S < D)

Severe abnormality

(S wave reversal)

Mild abnormality

(30%-49% pulsatility index)

Severe abnormality

(>50% pulsatility index)

Mild abnormality

(discontinuous biphasic flow)

Severe abnormality

(discontinuous monophasic flow)

, Venous Excess Ultrasound Score.

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accompanied with FOCUS assessment of RV function (along

with focused LUS), can be helpful in ruling out pulmonary

embolism.80-82

Regional Anesthesia

Interfascial plane blocks play an emerging role in periopera-

tive pain management.83 Due to the risks associated with epi-

dural and paravertebral techniques, interfascial plane blocks

(see Table 10) are a safer alternative for patients after cardiac

surgery and can be incorporated readily into a multimodal pain

management plan for a number of cardiac, thoracic, and vascu-

lar procedures, due to their relative ease of performance and

low level of complications.84,85 The implementation of these

blocks into multimodal cardiac enhanced recovery pathways

helps to minimize opioid consumption, reduce nausea and

vomiting, reduce postoperative ventilatory time, improve

patient satisfaction, and provide cost reductions.86,87 Involve-

ment of the cardiothoracic anesthesiologist with these regional

techniques has the additional benefit of providing further expe-

rience in performing LUS, as these interfascial plane blocks

are performed on the chest. In particular, it is important to be

facile in recognizing the presence of pneumothorax, which is a

complication associated with paravertebral blocks. Many cen-

ters use paravertebral blocks for pain control after thoracot-

omy, with these novel interfascial plane blocks playing an

important role in enhanced recovery pathways for cardiac and

thoracic surgeries. Nagaraja et al., in a comparison of thoracic

epidural analgesia versus bilateral erector spinae plane (ESP)

blocks for cardiac surgical procedures, revealed comparable

pain scores until 12 hours postoperatively, along with similar

Table 10

Ultrasound-Guided Regional Anesthesia Applications for the Cardiothoracic

Anesthesiologist

Regional Site of Injection of

Local Anesthetic

Surgical Procedures

PECS I and II blocks Between PMaM and

PMiM and between

PMiM and SAM

ICD, pacemaker

insertion

Right anterior

thoracotomy

SAPB Between the rib and

SAM or between

SAM and LDM

Thoracotomy, VATS,

Rib fracture

Minimally invasive

cardiac surgery

ESPB Between the TP and

ESM

Thoracotomy, VATS

Rib fracture

Sternotomy

PIFB/TTPB Between PMaM and

EIM/between IIM

and TTM

Sternotomy,

sternal fracture

Abbreviations: EIM, external intercostal muscle; ESM, erector spinae muscle;

ESPB, erector spinae plane block; ICD, implantable cardioverter-defibrillator;

IIM, internal intercostal muscle; LDM, latissimus dorsi muscle; PECS block,

pectoral nerve block; PIFB, pecto-intercostal fascial block; PMaM, pec major

muscle; PMiM, pec minor muscle; SAM, serratus anterior muscle; SAPB,

serratus anterior plane block; TP, transverse process; TTM, transversus

thoracic muscle; TTPB, transversus thoracis plane block; VATS, video-

assisted thoracoscopic surgery

ventilator days and ICU duration of stay, suggesting ESP block

as a viable alternative to thoracic epidural analgesia.88 In a sec-

ond patient-matched controlled study, continuous ESP block

was associated with decreased opioid consumption and earlier

mobilization after open cardiac surgery.89 In a randomized

controlled trial comparing serratus anterior plane block with

thoracic epidural analgesia for thoracotomy, Khalil et al. found

comparable pain scores and opioid consumption in both

groups, without a significant drop in mean arterial blood pres-

sure compared to baseline values in the serratus block group,

suggesting serratus plane block is a safe and effective alterna-

tive for postoperative analgesia in thoracotomy.90

Focused Assessment With Sonography in Trauma (FAST)

FAST is a commonly used diagnostic modality in trauma

patients to evaluate for intrabdominal fluid, as well as to guide

surgical interventions.91,92 In the postoperative setting, FAST

can be used rapidly to assess for intra-abdominal fluid collec-

tions in the workup for hypotension.93 The FAST examination

(see Table 11) can be performed easily at the bedside and

repeated according to the clinical context to guide continued

clinical management. In a Cochrane review on the evaluation

of POCUS for diagnosing thoracoabdominal injuries in blunt

trauma, positive findings, such as free fluid in thoracic or

abdominal cavities, major solid organ injuries, or lesions of

major vessels, were found to help regarding guiding manage-

ment decision, with a sensitivity of 0.68 and specificity of 0.95

for abdominal trauma.94 The Rapid Ultrasound for Shock and

Hypotension protocol is useful in patients with undifferenti-

ated shock, incorporating POCUS of the heart, IVC, Morison’s

pouch, aorta, and pneumothorax to identify rapidly reversible

causes of hypotension.95

POCUS in the Critical Care Setting

POCUS use in the critical care setting has burgeoned over

the past decades, with the core competencies of POCUS now

widely viewed as mandatory skill sets required by the modern

critical care medicine clinician.96 In the following, various

applications of POCUS in the ICU are addressed, including

ICU-specific echocardiography, LUS, abdominal ultrasound,

and vascular ultrasound.

Echocardiography, both TTE and TEE, long have been used

in the ICU. The causes of ICU-related hemodynamic instabil-

ity are diverse and include, but are not limited to, ventricular

dysfunction, myocardial ischemia, arrhythmias, sepsis, acute

blood loss, cardiac tamponade, and respiratory failure.97 Mul-

tiple examples exist within the literature demonstrating the

value of POCUS for diagnosing etiologies of hemodynamic

instability.95,98 The utility of TTE and TEE for the manage-

ment of hemodynamically unstable cardiac and patients after

noncardiac surgery has been shown to result in the determina-

tion of definitive diagnosis and subsequent change in clinical

management in 58.8% of patients in this context.99

Patients in the ICU benefiting from the use of POCUS also

include those requiring mechanical circulatory support

Table 11

Focused Assessment With Sonography in Trauma (FAST)

FAST View Structures Positive Signs

RUQ Liver, right kidney, hepatorenal pouch, diaphragm, right lung Morison’s pouch +, inferior pole of liver +

LUQ Spleen, left kidney, splenorenal recess, diaphragm, left lung Splenorenal pouch +, subphrenic space +

Pelvic sagittal and transverse Bladder, rectum, uterus (in women) Rectovesical pouch + (men)

Pouch of Douglas + (women)

Extended FAST

(e-FAST)

Lungs (LUS)

Cardiac (SC4C)

Pneumothorax

Hemothorax

Tamponade

Abbreviations: blood present; LUQ, left upper quadrant; LUS, lung ultrasound; RUQ, right upper quadrant; SC4C, subcostal four-chamber view.

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devices. Lu et al. demonstrated that trained intensivists can

perform adequate bedside TTE, TEE, and FAST examinations

on patients with mechanical circulatory support to guide medi-

cal and surgical management.100 In their study, 189 rescue

POCUS examinations were performed in a mixed cardiac med-

ical/surgical ICU, of which 4% led to extracorporeal mem-

brane oxygenation or ventricular assist device cannula

reposition, 2% lead to extracorporeal membrane oxygenation

or ventricular assist device setting change, and 1% led to right

ventricular assist device insertion.

In addition, POCUS has utility in the evaluation of fluid

responsiveness and to help guide appropriate fluid resuscita-

tion. When combined with LUS, echocardiography (specifi-

cally IVC imaging) can aid in fluid resuscitation management

in the critically ill, as demonstrated by Lee et al.101 By com-

bining current literature on lung and IVC ultrasound with

expert opinion on the ability of transthoracic ultrasound to pre-

dict fluid responsiveness, investigators were able to develop a

qualitative fluid resuscitation guide that categorized critically

ill patients into one of three broad groups: fluid resuscitate,

fluid test, and fluid restrict. Validation of this resuscitation

guide to help clinicians prescribe fluid therapy still is pending.

LUS is helpful in the evaluation of respiratory failure and

can diagnose acutely and guide treatment for a wide range of

lung pathologies, including pulmonary edema, pleural effu-

sion, pneumonia, and PTX.39 The FALLS protocol uses ele-

ments of the BLUE protocol, in combination with basic

echocardiography, to rule out other causes of shock (obstruc-

tive, cardiogenic, and hypovolemic) while highlighting an end-

point of resuscitation for distributive shock (the transition on

lung ultrasound from an A-profile to a B-profile).

In addition, LUS can aid in identifying the need for postop-

erative ventilatory support, as established by Dransart-Raye

et al.49 In this study, the presence of two areas of consolidated

lung was associated with a lower PaO2 per FIO2 ratio, the need

for postoperative ventilatory support, longer intensive care

stays, and episodes of ventilator-associated pneumonia requir-

ing antibiotics. In summary, LUS has the ability to diagnosis

acutely and accurately the causes of respiratory failure, aid in

volume resuscitation, identify patients likely to need postoper-

ative ventilatory support, and assist in weaning mechanical

ventilation.

Abdominal POCUS long has been used in emergency medi-

cine; has a reported sensitivity, specificity, and accuracy of

bedside sonography in identifying intraperitoneal hemorrhage

of 81.8%, 93.9%, and 90.9%, respectively; and is able be per-

formed in less than a minute in most ICU patients.102 The ini-

tial abdominal ultrasound protocol (FAST examination) has

been updated to the extended FAST examination (e-FAST),

which incorporates LUS for the assessment of PTX and was

found to have sensitivities and specificities superior to those of

CXR.103 FAST and e-FAST examinations are unique in their

ability to allow the intensivist to evaluate fresh postoperative

cardiac surgery patients experiencing hypotension for abdomi-

nal or thoracic hemorrhage. Abdominal ultrasound also has

been used to measure abdominal aortic aneurysm diameter and

to diagnose aneurysm rupture.104 In addition, bedside abdomi-

nal ultrasound can be used to evaluate, quantify, and guide par-

acentesis for abdominal ascites.6 POCUS also has been used to

diagnose obstructive nephropathy,6 hydronephrosis,105 neph-

rolithiasis,106 and bladder distention,107 as well as assisting in

difficult Foley catheter placement.108 All of these attributes

make abdominal ultrasound ideally suited for routine use in

the ICU.

The use of vascular ultrasound in the ICU ranges from vas-

cular access (central venous access, arterial access, and periph-

eral venous access) to the diagnosis of DVT. Central venous

access has been an accepted application of POCUS for a long

period of time, as demonstrated by multiple studies in the liter-

ature, dating back to the early 1990s.109-112 The benefits of

vascular ultrasound for central venous access include identifi-

cation of appropriate vessels for cannulation, identification of

aberrant vascular anatomy, verification of vessel patency, and

real-time confirmation of correct device placement,113 as well

as higher first attempt success rates and lower mechanical

complication rates.114 These benefits are associated most

strongly with internal jugular vein access, while being associ-

ated less strongly with subclavian and femoral vein access.114

POCUS also has been demonstrated to be superior to tradi-

tional blind cannulation techniques for both peripheral IVs and

arterial lines regarding success rate, time to cannulation, and

number of skin punctures.115-118 Another useful application of

vascular ultrasound in the ICU is the detection of DVT. One

study demonstrated that proximal lower-extremity DVT diag-

nosed by POCUS had an 86% sensitivity and 96% specificity

compared to formal ultrasound studies.119 POCUS allows for

the early detection and timely intervention in thromboembolic

disease processes seen in the ICU.

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Limitations of POCUS

It is critical to understand the limitations of each POCUS

application in clinical practice. Identification of an appropriate

POCUS indication based on clinical presentation and knowl-

edge of the pre-test probability are the first steps for successful

POCUS usage. Understanding the sensitivity and specificity of

each POCUS application, in comparison to other standard

techniques, plays a key role in the successful application of

POCUS for diagnostic purposes. Both individual patient fac-

tors and operator experience should be taken into consider-

ation. The complete clinical context of the patient should be

taken into account rather than simply treating the images

obtained. It is advisable to seek expert help and archive images

in situations of especially challenging POCUS diagnoses to

ensure safe patient care and avoid errors in clinical manage-

ment. Adequate training, as well as adherence to established

competencies and credentialing, are essential.

POCUS Education and Certification

Ultrasound use has become ever more ubiquitous across a

variety of medical disciplines, and ultrasound education is

now part of the core curriculum of multiple medical

schools.120 A four-component rationale for incorporating ultra-

sound education into medical education has been proposed by

education leaders in the California medical school system, pos-

iting that ultrasound education (1) enhances traditional medi-

cal education, (2) improves the diagnostic and procedural skill

set of trainees, (3) promotes more efficient patient care, and

(4) serves as a basis for more advanced and specialty-specific

ultrasound training during residency training and beyond.121

In the context of anesthesiology, POCUS education includes

echocardiography (transesophageal and transthoracic), proce-

dural ultrasound for vascular access and regional anesthesia,

as well as a growing variety of diagnostic uses (abdomen-

chest-airway evaluation, gastric volume determination, and

intracranial pressure estimation).122 While cardiac echocardi-

ography and ultrasound for regional anesthesia have been

well-established core elements of anesthesiology residency

education, as yet, no single structured POCUS curriculum or

professional society guidelines have become uniform across

all anesthesiology training programs.123 With the introduction

of novel surgical techniques two decades ago, a similar situa-

tion was faced by the American College of Surgeons (ACS),

with a need to demonstrate proficiency in these laparoscopic

and endoscopic surgeries. The ACS engendered the Funda-

mentals of Laparoscopic Surgery (FLS) and Fundamentals of

Endoscopic Surgery (FES) programs, which enable the evalua-

tion of surgical trainees’ knowledge base, technical skills, clin-

ical judgment, and overall competency in these respective

surgical areas.124,125 In 2019, the National Board of Echocardi-

ography, in conjunction with 9nine medical societies, adminis-

tered the first Examination of Special Competence in Critical

Care Echocardiography, with successful completion leading to

testamur status.126 The Examination of Special Competence in

Critical Care Echocardiography content transcends cardiac-

specific topics and includes content germane to a variety of

POCUS topics: ultrasound physics, ultrasound technical skills,

ultrasound image optimization, lung and pleura imaging, as

well as focused vascular and abdominal imaging. Though sig-

nificant momentum for POCUS education is occurring at the

medical school and graduate medical education level, a need

now exists to incorporate all of the aforementioned POCUS

applications and content into both anesthesiology residency

education and for those clinicians beyond training. For clini-

cians beyond training seeking ultrasound and POCUS training,

a variety of regional and national medical societies (eg, Ameri-

can Society of Anesthesiologists, Society of Critical Care

Medicine, American Society of Regional Anesthesia, Society

of Cardiovascular Anesthesiologists), as well as independent

commercial organizations (eg, POCUS Certification Acad-

emy), offer POCUS-related educational activities; additional

options after training typically include self-directed learning

and simulation-based training.123 In a 2017 survey of a variety

of 343 critical care medicine clinicians of varying back-

grounds, as compared to other specialties, those clinicians

with primary residency training in emergency medicine were

more likely to have received POCUS training during their resi-

dency training (73.5%, p < 0.001) compared to the other sur-

veyed specialties (8.7%). Of the nonemergency medicine

specialties, including anesthesiology, POCUS training was

derived from an external educational course (26.5%) or

through self-guided learning (17.2%).127 To date, there is no

literature specifically examining POCUS education in the

training context versus thereafter via conferences and work-

shops. Hence, at present, quality assurance as to the education

experience for a given clinician only may be assessed by com-

petency evaluations, which include mandating a minimum

number of reviewed POCUS scans and imaging analogous to

existing echocardiography certification pathways.128 As grow-

ing numbers of perioperative clinicians, who already have

completed training seek POCUS education, as well as the

broad variety of POCUS training options outside of the formal

medical education systems, the need for codifying what consti-

tutes adequate POCUS education and competency should be

prioritized.

As POCUS continues to evolve in its diagnostic and proce-

dural applications, there is yet to be a single unified or codified

POCUS training curriculum in the United States analogous to

the ACS FLS and FES programs. In a 2016 call to action, Mah-

mood et al. outlined three components needed for the develop-

ment of a core POCUS educational program: (1) during

anesthesiology residency, POCUS training should be

“continuous and structured” and (2) residency programs

should develop individual ultrasound education tools and

means for evaluation that align with existing Accreditation

Council for Graduate Medical Education milestone expecta-

tions.122 Analogous to the aforementioned FLS and FES pro-

grams, anesthesiology residency programs also should work to

develop a structured and unified approach to anesthesiology

POCUS training, and (3) additional advanced POCUS con-

cepts and skills training at the fellowship level or beyond also

should be part of constructing a unified POCUS educational

Table 12

Pathways for Attaining POCUS Competency

POCUS Competency Pathways

Supervised Training Pathway Established Expertise Pathway

POCUS Modality Minimum No. of supervised

studies personally performed

and interpreted

Minimum No. of additional

supervised studies

interpreted but not

personally performed

Obtain written/signed endorsement from 3 attending physicians

attesting to the following:

1. Explain why letter author is qualified to write the letter.y

2. Describe the letter author’s relationship to the candidate

applying for POCUS privileging.

3. Include a specific attestation statement listed below as pertains

to the POCUS domain(s) being discussed (see below).

Each supporting letter should be from an attending physician who

has directly observed candidates’ competence for the given

POCUS application.

Expertise Pathway: Attestation Statements for POCUS Modalities

Focused airway u/s 30 20 “I personally attest that Dr. <Insert Name> is qualified to perform

focused airway u/s. Specifically, in my time working with him/her,

I observed that he/she could properly use u/s to evaluate for,

among other things, the following: laryngo-tracheal anatomy and

endobronchial vs esophageal vs endotracheal intubation.”

FAST exam 30 20 “I personally attest that Dr. <Insert Name> is qualified to perform a

FAST exam. Specifically, in my time working with him/her, I have

observed that he/she could properly use u/s to evaluate for life-

threatening conditions in trauma patients, including but not limited

to: intraperitoneal fluid/hemorrhage and pericardial effusion/

hemopericardium.”

Focused cardiac u/s 50 100 “I personally attest that Dr. <Insert Name> is qualified to perform

focused cardiac u/s. Specifically, in my time working with him/

her, I have observed that he/she could properly use cardiac u/s to

evaluate for, among other things, the following: pericardial

effusion/cardiac tamponade, gross left ventricular dysfunction,

gross right ventricular dysfunction, and gross hypovolemia.”

Focused gastric u/s 30 20 “I personally attest that Dr. <Insert Name> is qualified to perform

focused gastric u/s. Specifically, in my time working with him/her,

I observed that he/she could properly use u/s to evaluate for,

among other things, the following: full stomach (defined as solid

gastric content or clear fluid in excess of baseline secretions

[Grade 2 antrum]).”

Focused pleural and lung u/s 30 20 “I personally attest that Dr. <Insert Name> is qualified to perform

focused lung u/s. Specifically, in my time working with him/her, I

have observed that he/she could properly use lung u/s to evaluate

for, among other things, the following: pneumothorax, pleural

effusions, interstitial syndromes, and consolidation.”

Focused u/s for DVT 30 20 “I personally attest that Dr. <Insert Name> is qualified to perform

focused u/s for evaluation of DVT. Specifically, in my time

working with him/her, I have observed that he/she could properly

use u/s to evaluate for, among other things, the following: a DVT

in the proximal lower extremity veins and in the internal jugular

vein.

NOTE. Based on the 2019 Committee Work Product on Diagnostic Point-of-Care Ultrasound of the American Society of Anesthesiologists. (A copy of the full text

can be obtained from ASA, 1061 American Ln, Schaumburg, IL 60173-4973 or online at www.asahq.org.).132

Abbreviations: DVT, deep vein thrombosis; FAST, focused assessment with sonography in trauma; POCUS, point-of-care ultrasound; u/s, ultrasound.

yExamples: (1) possession of a relevant national certificate or certification in u/s, (2) history of teaching at relevant u/s workshops, (3) history of performing and

interpreting diagnostic u/s examinations at their home institution, with an estimated annual volume of relevant u/s examinations that they personally perform

and interpret and number of years they have practiced this modality of diagnostic u/s.

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curriculum.122 In addition to these three elements, other

authors also highlighted that a complete POCUS educational

curriculum should include maintenance of POCUS skills after

training and professional development.129 The International

Federation of Emergency Medicine published a consensus

document in 2015 that provided stepwise guidance for POCUS

training in their domain; however, this POCUS training

framework is relatively generic and applicable to anesthesiol-

ogy.130 Applied to POCUS education, this framework began

with defining what applications (core and advanced techni-

ques) are to be taught and how each of these applications will

be taught. Regarding POCUS education methodology, a four-

step process should be used: application introduction, experi-

ential use and development (ie, documented via case log),

Table 13

POCUS Curriculum Levels of Competency

Competency Level Level Description Included Competencies

Level 1 � Core � Expected standard of knowledge and practice� Generic and basic competences to be obtained during residency

training

� Able to perform common u/s examinations and interventions

safely and accurately� Able to recognize normal and abnormal anatomy and pathology� Able to use u/s in real time to guide common invasive

procedures� Able to recognize when consultation for a second opinion is

indicated� Able to understand benefits of u/s imaging and its value and rela-

tionship to other imaging modalities used in perioperative

medicine

Level 2 � Extended � More advanced level of skill and practice; level 2 practice for

clinicians with specialized interest in u/s� Overlapping nature of practice is proposed such that a clinician

may be level 2 in one area (ie, vascular access) and level 1 in

another (ie, regional anesthesia).

� Significant experience of level 1 practice (ie, >12 months)� Able to perform the complete range of examinations� Able to recognize significant organ system-specific pathology� Able to use u/s to guide full range of procedures related to prac-

tice area� Able to act as mentor and instructor for level 1 clinicians� Able to accept referrals from level 1 clinicians

Level 3 �Advanced � Specialized and advanced training (ie, advanced echocardiogra-

phy training)� Level 3 practice is unlikely to be pertinent to most practicing

perioperative clinicians.

� Able to accept referrals from level 2 clinicians and perform spe-

cialized examinations� Level 3 clinicians are involved in all areas of u/s training and

participate in u/s research.

NOTE. Adapted from the Association of Anaesthetists of Great Britain and Ireland, the Royal College of Anaesthetists, and the Intensive Care Society’s

“Ultrasound in Anaesthesia and Intensive Care: A Guide to Training”.133

Abbreviations: CCM, critical care medicine; u/s, ultrasound.

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obtaining competence (expert review of case log along with

skills assessment), and maintenance of competency (continu-

ing POCUS education and case log maintenance). In assigning

levels of competency, neither the Accreditation Council for

Graduate Medical Education nor any specific American anes-

thesiology society has yet to set standards, milestones, or

required levels of training specific to POCUS.128 However, the

American Board of Anesthesiology, as part of the Objective

Structured Clinical Examination component to board certifica-

tion, includes testing candidates’ interpretation of basic TEE,

basic TTE, and chest ultrasound imaging, with specific

POCUS applications being added to the Objective Structured

Clinical Examination beginning in 2022.131 Building on the

aforementioned POCUS educational framework concepts, in

2019 the American Society of Anesthesiologists convened its

first Ad Hoc Committee on POCUS, which, in part, specifi-

cally addressed the minimum level of training in diagnostic

POCUS needed for competence. See Table 12 for the Ameri-

can Society of Anesthesiologists Ad Hoc Committee’s recom-

mendations on training requirements required to be considered

POCUS competent based on the 2019 Committee Work Prod-

uct on Diagnostic Point-of-Care Ultrasound of the American

Society of Anesthesiologists.132 The Association of Anaesthe-

tists of Great Britain and Ireland and the Intensive Care Soci-

ety POCUS training curriculum offer three competency levels

that could be applied similarly in the United States (see

Table 13).133

Given the expertise and familiarity of cardiothoracic anes-

thesiologists with echocardiography and perioperative ultra-

sound applications, it is natural to conclude that they should

play an important role in all aspects of POCUS education.

Conclusions

POCUS is a valuable bedside diagnostic tool for the expedi-

tious diagnosis of a variety of acute and life-threatening condi-

tions, clearly earning its burgeoning reputation as the 21st-

century stethoscope. For each organ system evaluated, the

application of POCUS has its own unique advantages. LUS

has better sensitivity and specificity over CXR for certain lung

conditions, such as PTX, pulmonary edema, lung consolida-

tion, and pleural effusion. 40,42,44 Cardiac ultrasound has a cen-

tral role in the evaluation of challenging hemodynamic

situations and undifferentiated shock states. Combinations of

POCUS modalities, such as LUS along with FOCUS, have

higher rates of accurate diagnosis in complex situations and

multiorgan system involvement.134,135 Diagnosis and treat-

ment using POCUS should be within the clinical context of the

patient, and the ultrasonographer must be aware fully of the

limitations.136,137 Analogous to the National Board of Echo-

cardiography training and certification standards for echocar-

diography, standardizing POCUS education and delineating

competency levels also are central to ensuring appropriate

quality assurance. This is even more critical as POCUS use

increases and more physicians seek to attain POCUS expertise

to incorporate this technology more widely into routine clini-

cal practice. With the current available and growing evidence

of clinical value of POCUS, its utility across the perioperative

arena adds enormous benefit to clinical decision-making.

Conflict of Interest

The authors declare no competing interests.

ARTICLE IN PRESS

H. Kalagara et al. / Journal of Cardiothoracic and Vascular Anesthesia 00 (2021) 1�16 13

Supplementary materials

Supplementary material associated with this article can be

found, in the online version, at doi:10.1053/j.jvca.2021.01.018.

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