focused cardiac and lung ultrasonography: implications and

Perioperative focused cardiac and lung ultrasonography

Adress for correspondence: José L. Díaz-Gómez, MDDepartments of Anesthesiology,Critical Care, and NeurosurgeryMayo Clinic4500 San Pablo RoadJacksonville, FL 32224 USAE-mail: [email protected]

Romanian Journal of Anaesthesia and Intensive Care 2016 Vol 23 No 1, 41-54

REVIEW ARTICLE

Focused cardiac and lung ultrasonography: implications andapplicability in the perioperative period

José L. Díaz-Gómez1,2,3, Gabriele Via5, Harish Ramakrishna4

1 Department of Critical Care Medicine, Mayo Clinic FL, USA2 Department of Anesthesiology, Mayo Clinic FL, USA3 Department of Neurologic Surgery, Mayo Clinic FL, USA4 Department of Anesthesiology, Mayo Clinic AZ, USA5 Department of Anesthesia and Intensive Care, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy

AbstractFocused ultrasonography in anesthesia (FUSA) can be a procedural and diagnostic tool, as well as

potentially a tool for monitoring, and can facilitate the perioperative management of surgical patients. Itsutilization is proposed within the anesthesiologist and/or intensivist scope of practice. However, there aresignificant barriers to more generalized use, but evidence continues to evolve that might one day make thispractice a standard of care in the perioperative period.

Currently, the most widely used applications of FUSA include the guidance and characterization ofperioperative shock (acute cor pulmonale, left ventricular dysfunction, cardiac tamponade, and hypovolemia)and acute respiratory failure (pneumothorax, acute pulmonary edema, large pleural effusion, major atelectasis,and consolidation). Increased diagnostic accuracy of all of these clinical conditions makes FUSA valuablein the perioperative period. Furthermore, FUSA can be applied to other anesthesiology fields, such asairway management and evaluation of gastric content in surgical emergencies.

Keywords: focused cardiac ultrasound, lung ultrasound, shock, hypoxemia

Received: 2 February 2016 / Accepted: 1 March 2016 Rom J Anaesth Int Care 2016; 23: 41-54

IntroductionUltrasonography in the anesthesiology and critical

care environments provides noninvasive, rapid, andaccurate diagnostic information for patients withpotentially life-threatening conditions. In contrast to for-mal comprehensive echocardiography via cardiologyservices, focused cardiac ultrasound evaluationsprovide quickly obtained goal-oriented information [1],which is better suited for the dynamic state of thesurgical patient in the perioperative period [2, 3].

Focused cardiac ultrasound –sonoanatomyFocused cardiac ultrasound exclusively uses the

simplest modalities of Echocardiography: 2D and M-Mode. The preliminary step is being cognizant of the

The combined application of both focused cardiacand lung ultrasound is very useful in the initialassessment of surgical patients who present with shockand/or acute respiratory failure in the perioperativeperiod. This new ultrasonography-driven approach hassignificantly evolved over the past few years. Initially,most indications for FUSA were related to centralvenous vascular access and regional anesthesia.However, FUSA is currently touted as the most usefulpoint-of-care imaging modality that can enhancediagnostic accuracy. This review will facilitate anunderstanding of the utilization of ultrasound-guidedfocused cardiac and lung ultrasound in the perioperativesetting.

DOI: http://dx.doi.org/10.21454/rjaic.7518.231.lus

Díaz-Gómez et al.42

standard position of the probe on the chest that is neededto acquire adequate images of the heart and greatvessels. In emergency conditions, the subcostal viewshould be obtained first in order to avoid any delay inthe commencement of chest compressions if cardiacarrest occurs (Figure 1). To facilitate orientation, theindicator on the transducer corresponds to the markeron the side of the ultrasound sector on the monitor (byconvention, the marker is displayed in the top right ofthe ultrasound sector). This is the standard position ofthe marker adopted by most echocardiography labo-ratories.

The cardiac probe has a small footprint to createthe acoustic windows through the intercostal space.The application of firm pressure along with gel is ne-cessary to optimize the ultrasound conduction betweenthe skin and transducer. The probe should be held likea pen for all views, except the subcostal view where itshould instead be gripped from the top (Figure 1E).

Fig. 1. Subcostal view. A. Orientation of the probe indicator; B. Direction of the ultrasound beam on the heart; C. Identification ofheart chambers on subcostal view; D. Echocardiographic appearance of the subcostal view; E. Overhand grip of the ultrasound probe

– only used for the subcostal view (by permission of the Mayo Foundation for Medical Education and Research; all rights reserved)

Basic scanning movements with thetransducerThe following transducer movements are funda-

mental in order to procure all transthoracic echocardio-graphy views. Hence, it is crucial to acknowledge themso the focused cardiac ultrasound examination isaccurately performed in a timely fashion.

Sliding: displacement of the probe between higheror lower intercostal spaces. This is an important initialmovement while procuring the parasternal long-axisview, but is generally applicable to all views.

Rotation: the clockwise or counterclockwise move-ment of the probe while maintaining the same axis ofpenetration of the ultrasound beam. This probemovement is applicable to all views.

• Clockwise: from the parasternal long axis to theshort axis view (from 10 o’clock to 2 o’clock)

• Counterclockwise: from the subcostal 4-chamberview to the IVC view (from 3 o’clock to 12o’clock); from the apical 4-chamber to the 2-chamber view (from 3 o’clock to 12 o’clock)Rocking: Incline the probe in the plane of the

indicator. In the apical view, for example, tilting of theprobe to your right (patient’s left side) will facilitatethe visualization of the right ventricle free wall.

Tilting: Incline the probe in a plane perpendicularto the one of the indicator. For example, in the para-sternal short axis views, this movement is crucial inthe identification of different planes from the base ofthe heart (aortic valve and right ventricular outflowtract, then the mitral valve, and finally the mid-papillaryview) (Figure 2).

Important caveats to obtaining a good view1. After obtaining a “reasonably good” view, only

perform slow movements with the probe to optimize.2. Perform one movement at any given time to

understand how the image changes according to yourmanipulations (i.e., do not combine rotation and tiltingor sliding and rocking, etc.).

Optimizing echocardiography imagesThe following probe manipulations are helpful for

optimizing transthoracic echocardiography images oncea reasonably good view has been obtained.

Perioperative focused cardiac and lung ultrasonography 43

Fig. 2. Parasternal short-axis view. A. Orientation of the probeindicator; B. Direction of the ultrasound beam on the heart; C.-H.Identification of the heart chambers and echocardiographicappearance on parasternal – short-axis view; C.-D. Aortic valvelevel; E.-F. Mitral valve level; G-H. Mid-papillary level. Thistransition of views is achieved while the sonographer makes atilting (“fanning”) movement of the probe. The aortic level view isobtained with superior “fanning” of the probe and mitral level andmid papillary view with inferior direction “fanning” of the probe(by permission of the Mayo Foundation for Medical Education andResearch; all rights reserved)

Parasternal Long-Axis:• The four criteria are important to assure a good

parasternal long-axis view:– Lack of visualization of the apex in the image obtained– Visible aortic and mitral valves– Horizontal orientation of the heart– Recognition of the descending aorta

• If LV apex is visible, slide the transducer moremedially (closer to the sternum).

Parasternal Short-Axis (midpapillary) View:• At times, the best view is obtained by sliding the

probe one intercostal space up or down. If this is not

successful, obtain the long-axis parasternal view againand start rotation from the right to the left shouldervery slowly.

• If LV is asymmetric, rotate the transducer eitherclockwise or counterclockwise.

Apical:• If the heart appears to be tilted to the right, slide

the probe more laterally and vice versa.• If the atria chambers are not visible, use upward

rocking (anterior to posterior) movements.• If you are unable to visualize the right ventricle,

attempt to tilt the transducer to the right.Subcostal:Flatten (lower) the angle between the transducer

and the skin as much as possible. A good point ofreference is the visualization of both atrioventricularvalves in the same plane.

Position of the patient and the operator andprobe orientationOften the perioperative patient is lying in the supine

position. This is the most convenient position to obtainthe subcostal view. In contrast, the left lateral decubitusposition enables a closer position of the heart withinthe chest wall and improves the image quality of theapical and parasternal views. This can be more easilyattempted in the Post-anesthesia Care Unit (PACU)or during the preanesthesia assessment.

To facilitate image interpretation, the cardiacultrasound views are obtained by cutting planes thateither intersect the major axis of the heart (long-axisviews characterized by including the image structuresof the base and apex of the heart) or that are perpen-dicular to this axis (short-axis views).

The Focused Assessed Transthoracic Echocar-diography (FATE) protocol is a focused cardiacultrasound protocol commonly applied in the periope-rative period [4]. We utilize the FATE protocol for theillustration of the echocardiography views. In thesections below, a distinct, practical, ultrasound-drivenapproach to shock and acute respiratory failure willbe described (Figure 3).

In Table 1, the techniques for obtaining the echo-cardiographic views during focused cardiac ultrasoundare described.

Using M-mode to assess inferior vena cava (IVC)diameter facilitates the calculation of the distensibilityindex (patients receiving mechanical ventilatorysupport) or collapsibility index (spontaneouslybreathing patients) and starting from the initial subcostalview, use a counter-clockwise rotation from 3 o’clockto 12 o’clock (90°) (Figure 4).


Table 1. Focused Cardiac Ultrasound – obtaining echocardiographic views

Loca t ion of t r a n sd u cer P rob e or ien t at ion ma rk er

Sector Dep th on mon itor

Help fu l t ip s

Subcostal 2 cm below xyphoid process or slightly toward RUQ if chest tubes in place

~ 2-3 o’clock 15-25 cm Hold the transducer from the top; apply angulations between 10-40 degrees. Supine position, bend knees (if able)

Subcostal – Inferior Vena Cava

From the previous view rotate the transducer 90 degrees counterclockwise

~ 12 o’clock 15-20 cm Keep junction of right atrium and IVC in the center of the screen. Need to appreciate the IVC merging into right atrium

Apical Find the point of maximal impulse if feasible. Otherwise from anterior axillar line to nipple. Female patients – under the breast crease

~ 3 o’clock 14-18 cm Probe must be angled (60 degrees) toward right hemithorax. Assure good contact with the rib. You are “sneaking” in between those two ribs!

Parasternal – long axis

3rd – 4th intercostal space ~ 11 o’clock (Patient’s right shoulder)

12-20 cm (24 cm if pleural/ pericardial effusion are suspected)

Left lateral decubitus position if not able to obtain a “good view” in supine position

Parasternal – short axis

Rotate 90 degrees clockwise from the parasternal-long axis view, so ~ 2 o’clock

~ 2 o’clock (Left shoulder)

12-16 cm With “tilting” movement of the probe Aortic valve level: the transducer face slightly upward toward the patient’s right shoulder Mitral valve level: the transducer is perpendicular to chest wall Papillary muscle level: the transducer faces slightly downward toward the patent’s left flank

Fig. 3. FATE protocol (by permission of the Mayo Foundationfor Medical Education and Research; all rights reserved)

(expressed as percentage)

A distensibility index of >18% predicts fluid res-ponsiveness with a positive predictive value of 93%and a negative predictive value of 92% [5].

Fig. 4. Subcostal – IVC view. Distensibility Index (MechanicalVentilation): M-Mode assessment of the Inferior Vena CavaVariation. The phase array marker should be oriented cephalad (12o’clock). A gentle right to left “sweep” movement will facilitatethe recognition of the IVC to right atria junction. The IVC diametermeasurement should be taken 2 cm to 3 cm from the IVC to theright atrial junction (by permission of the Mayo Foundation forMedical Education and Research; all rights reserved)

The apical 4-chamber view is similar to the subcostalview (vertical versus horizontal orientation of the hearton the screen). Thus, it is helpful to compare thesetwo echocardiographic views (Figure 5).


Fig. 5. Apical view. A. Orientation of the probe indicator; B. Direction of the ultrasound beam on theheart; C. Identification of heart chambers on apical view; D. Echocardiographic appearance of the apicalview (by permission of the Mayo Foundation for Medical Education and Research; all rights reserved)

Lung ultrasound – sonoanatomyWhile a significant portion of critical care and

surgical anesthesia imaging is dedicated to transthoracicechocardiography, ultrasonographic imaging of the lunghas demonstrable benefit in diagnosing patients withacute respiratory failure with or without concomitantarterial hypotension. For instance, the initial FATEprotocol included the examination of the pleura withthe intention of describing large pleural effusion thatcan contribute or cause arterial hypotension in criticallyill patients [4]. A growing body of evidence has shownexcellent sensitivity and specificity in identifyingpneumothorax, pulmonary edema, COPD exacerbation,and pneumonia in the critically ill patient population[6]. Furthermore, the combination of focused cardiacand lung ultrasound facilitates the characterization ofpulmonary edema (hydrostatic versus nonhydrostatic)in critically ill patients [7].

This section summarizes an overview of lungultrasound in the perioperative period. First, we describethe sonoanatomy of lung using the linear (high-fre-quency) probe. Second, we present the clinical signifi-cance of lung ultrasonography. Third, an ultrasound-driven approach with patients with acute respiratoryfailure in the perioperative period is presented.

Step 1: Technique and identification of normal andabnormal signs/patterns in focused lung ultra-sonography with the linear probe:

Technique: As described previously by Lichtenstein[8], the anterior chest wall can be divided in fourquadrants while the patient is in the supine position.The linear probe should be longitudinally appliedperpendicular to the wall for all quadrants. In the caseof an unclear image, rule out the presence of sub-cutaneous emphysema or an overlying obstruction(dressings, EKG pads, etc.) (Figure 6).

Lung ultrasound in the perioperative periodAs with focused cardiac ultrasound, a significant

portion of lung ultrasonography relies on the recognitionof ultrasound “patterns” that are pathognomonic ofassociated disease processes. Lung ultrasound requiresthe integration of the segmental patterns (at eachscanning spot) together in an overall lung pattern [9].A complete lung ultrasound examination requires linearand phased array transducers. While direct visualizationof the pleural-lung interface, of pleural effusions, andof completely de-aerated lung areas (consolidations)is possible, the air-filled lung cannot be visualized. It isin fact obscured by the high ultrasound reflectivity ofthe air-tissue interface represented by the end of pre-


Fig. 6. Lung Ultrasound Technique. A. Two-dimensional imaging of normal lung and pleural sliding using alinear probe. Maximal depth is 6 cm; B. Probe should be placed perpendicular to the chest wall with the probeindicator facing cephalad. Gentle tilting improves the images due to increased reflection of pleural line(by permission of the Mayo Foundation for Medical Education and Research; all rights reserved)

pleural tissues and the beginning of the aerated lungtissue (at the level of the pleural layers) touching. Toovercome this limitation, the artefacts from thisphenomenon have been studied and have been distilledinto specific ultrasound patterns associated with specificpathologies.

Initial assessment: patients with clinical suspicionof pneumothorax or complete atelectasis – the“Five Ls” Approach

The following LUS signs are based on the Interna-tional Meeting on Lung Ultrasound Conference, whichstandardized all of them with expert consensus [6].

The first step (lung/pleura sliding) should be per-formed with the higher frequency linear probe (7.5-12 MHz). This linear transducer provides improvedresolution of structures that are closer to the probe orin the near field, most notably the pleura. As such,examination for clinical suspicion of pneumothoraxlends itself to this technique.

1. First “L” – Lung Sliding: A sliding movementbetween the visceral and parietal pleura is describedas the “lung sliding sign” [6]. It consists of the respi-rophasic shimmering of the pleural line, the ultrasoundrepresentation of the pleural layers touching (i.e., thephysical site of the tissue-air interface mentionedabove). It is a dynamic process demonstrated with two-dimensional ultrasonography in real time. Detection ofthis finding in the parasternal areas of the lung rulesout pneumothorax (in the site of scanning) with 100%NPV. When the lung sliding is not detected, pneumo-thorax is possible but needs a confirmatory sign obtainedby the extension of the exam to the lateral regions ofthe chest (see “lung point” below). Other conditionssuch as adhesions due to previous thoracic surgeries,very low lung compliance, may otherwise mimicabsence of lung sliding and pneumothorax. Sono-anatomy and Lung Sliding: The obtained sonographic

image includes: (1) subcutaneous tissue and intercostalmuscles (2) the ribs and (3) the pleural line (ahyperechoic line) (Figure 6).

The representation of this lung sliding in M-modecomplements the evaluation including the static thoracicwall (hence represented by straight lines), and thedynamic pleural line movement generates dynamicdistal artifacts (represented as a granular pattern thathas been referred to as the “seashore sign” becauseits appearance is similar to sand on a beach). Theabsence of lung sliding in M-mode has been called the“barcode sign” (Figure 7) [10, 11].

2. Second “L” – Lung Point: The lung point is auseful sign for the confirmatory diagnosis of pneumo-thorax. It can be found in real time (two-dimensionalultrasound) or M-mode. It indicates the dynamic pointof transition (at inspiration) between normal sliding andthe absence of sliding (i.e., the point where the lungagain touches the chest wall, the boundary of apneumothorax air collection). This sign is consideredvery specific (98%-100%) for pneumothorax (Figure7) [12-14].

3. Third “L” – Lung Pulse: The lung pulse is auseful sign for the diagnosis of absence of ventilation,potentially leading to complete atelectasis; when thelung area investigated is in this condition, it shows anintermittent small motion synchronous with theheartbeat, meaning that there is still air content in thelung that is no longer in communication with the airway(the non ventilated lung area becomes like a bag fullof air, receiving and transmitting the kicks of the“beating neighbor”). The cardiac pulsation appearanceat the pleural line in M-mode and the absence of lungsliding in real-time two-dimensional ultrasonographycharacterizes the lung pulse sign. The sensitivity andspecificity of the lung pulse sign for complete atelectasisare 70%-99% and 92%-100%, respectively (Figure8) [15].


Fig. 7. A. Normal lung and pleural sliding using a linear probe and M-mode; B. M-mode representation of the Lung point andpartial pneumothorax (mix of granular-normal with arrows and horizontal-pneumothorax patterns); C. Barcode sign,pneumothorax. The linear probe marker should be oriented cephalad (12 o’clock). A slight tilting of the probe will facilitate therecognition of higher reflectance and ultrasound appearance of the pleural-lung interface and sliding movement (by permissionof the Mayo Foundation for Medical Education and Research; all rights reserved)

Fig. 8. Two dimensional and M-mode representation of Lungpulse. Lung pulse is suggestive of major lung collapse. The linearprobe marker should be oriented cephalad (12 o’clock) (bypermission of the Mayo Foundation for Medical Education andResearch; all rights reserved)

4. Fourth “L” – “A” Lines: Under normal con-ditions, the ultrasound signal in the lung is completelyreflected by the tissue-air interface at the level of thepleural line. This reflection generates reverberationsthat project the pleural line beyond itself in the mid andfar field as horizontal artifacts that are parallel to thepleural line and are multiplicative of the distancebetween the skin and the pleural line. The “A” linesconstitute the basic artifact of normal lungs (Figure9). It is important to acknowledge that in absence ofany pleural motion (either lung sliding or lung pulse [8,16, 17]), “A” lines are also present in case of pneu-mthorax.

5. Fifth “L” – “B” Lines: These lines describethe change in the normal artifacts of the lung and aredetermined by a change in density of the subpleurallung tissue content (pathological involvement of thelung interstitium or the alveolar airspaces, or thickeningof interlobular septa). This is either a consequence ofincreased extravascular lung water or of decreased

air content. The “B” line is defined as a hyperechoiclaser-like signal that fans out from the pleural line thatmoves with the pleural sliding and reaches the edge ofthe screen, erasing the “A” lines. At least three lungcomets between two ribs in one longitudinal scan mustbe identified to constitute a positive “B pattern”, thehallmark of this change in peripheral lung density. Oneof the most useful applications of lung ultrasonographyin the perioperative patient is the early detection ofacute interstitial pulmonary edema, especially in patients

who undergo surgical operations without any preope-rative respiratory symptoms (Figure 10). Moreover,other causes of the alveolar-interstitial syndrome thatcan present “B” lines include pneumonia and pre-exist-ing pulmonary fibrosis. Hence, the ultrasound visuali-zation of interstitial pulmonary edema syndrome is notspecific for pulmonary edema but highly sensitive; its

Fig. 9. Representation of normal “A” lines with linear transducer.These lines have horizontal orientation. The linear probe markershould be oriented cephalad (12 o’clock) (by permission of theMayo Foundation for Medical Education and Research; all rightsreserved)


applicability in previously asymptomatic patients in theperioperative setting makes it a very valuable tool [18].

Fig. 10. Representation of abnormal “B” lines with phase arraytransducer. The phase array probe marker should be orientedcephalad (12 o’clock). These lines have vertical orientation and arewell defined and laser like. “B” lines arise from the pleural line,erase “A” lines, and move with lung sliding. They also shouldextend throughout the field shown on the image. In this case, thereare five “B” lines which are suggestive of pulmonary edema (bypermission of the Mayo Foundation for Medical Education andResearch; all rights reserved)

The anesthesiologist can face the clinical scenarioof hypoxemic acute respiratory failure due to pul-monary edema. Certainly, a combined focused cardiacand lung ultrasound examination can increase thediagnostic accuracy at the bedside with a noninvasiveapproach. A recent investigation demonstrated that alow B-line ratio in lung ultrasound suggests miscella-neous causes of acute respiratory failure. In contrast,left-sided pleural effusions, moderate or severe leftventricular dysfunction and increased IVC diameterwith low variability indicated cardiogenic pulmonaryedema rather than ARDS. A scoring system showeda remarkable area under the curve correlation [7].

Step 2: Technique and identification of normal andabnormal signs/patterns in lung ultrasonographywith the phased array probe

The phased array probe allows for adequatepenetration and image depth to assess the liver orspleen (left side), diaphragm, and lung bases whenconsolidation or effusion (the other two remaining lungultrasound patterns) appears. Consolidation refers tothe image of a completely air-deprived lung reachingthe ultrasound characteristics of a solid organ, forexample with the same echoic properties as the liver.Effusion physiologically refers to when there is nofluid in the costophrenic sinuses. When fluid accu-

mulates, it appears as a “hypoechoic” space betweenthe base of the lung and the diaphragm (Figure 11).The probe marker should be directed in the cephaladposition to obtain lung imaging. This orientation is iden-tical to the linear probe as illustrated above. However,when there is a more significant accumulation of fluid,the hypoechoic imaging is more evident, and thecollapsed lower lobe lung takes the appearance of anechoic, consolidated, organ (Figure 11). The nature andquantification of pleural effusion can be accuratelyassessed with lung ultrasonography. The amount ofpleural effusion can be estimated with a formulaproposed by Balik: V (mL) = 20 × Sep (mm); whereV = volume of pleural effusion and Sep = distancebetween the two pleura layers [19, 20]. Semiquan-tification, for the purpose of rapid decision making oneffusion drainage has also been proposed [21].

Fig. 11. Large right pleural effusion. The phase array probe markershould be oriented cephalad (12 o’clock). The ultrasoundexamination should start at the right flank and slight posteriortilting will improve the image quality of the kidney. Then, a slowsliding in cephalad direction will facilitate the recognition of theliver, diaphragm, large pleural effusion and to the collapsed lung(by permission of the Mayo Foundation for Medical Education andResearch; all rights reserved)

Focused cardiac ultrasound-drivenapproach to the surgical patient presentingwith arterial hypotension, shock, or cardiacarrestFocused echocardiography as part of FUSA should

be used in the initial assessment of patients withundifferentiated shock (Figure 3). Furthermore, theimpact of this approach is that it increases diagnosticaccuracy and optimizes management of shock.Although most of the evidence regarding focusedcardiac ultrasound has been obtained from the emer-gency room and intensive care unit scenarios, causesof shock are similar in perioperative setting. These


investigations have attempted to demonstrate theusefulness of narrowing the etiologies of shock statesand subsequent change in management [4, 22-24].

It would seem logical that new information fromdiagnostic tests would lead to better clinical outcomes.However, this is not so straightforward with the appli-cation of focused cardiac ultrasound protocols in anes-thesia or critical care medicine; the greatest evidencesupporting their use is currently represented by theeffective mitigation of diagnostic uncertainty [25].More importantly, with existing evidence, a rigorousrandomized clinical trial might be considered unethicalat this time [1].

In emergency conditions such as periresuscitation,an ultrasound-driven approach is appealing to anes-thesiologists and/or critical care practitioners becausethis tool is noninvasive and a timely assessment canbe exercised any time as point-of-care. The mostcritical information obtained in cardiac arrest is theidentification of the mechanical contractility duringpulseless electrical activity (PEA) cardiac arrest. Thiscondition has been named “Pseudo-PEA arrest”, andit is associated with higher survival than PEA cardiacarrest [26]. In his study, Breitkreutz demonstrated thatthe image procurement was feasible in 96% of the204 cardiac arrest cases. Thus, it is reasonable to con-sider that this ultrasonography applicability be incor-porated in the advanced cardiac life support in thefuture. Other authors have demonstrated similar find-ings in the cardiac arrest setting [27, 28].

Focused cardiac ultrasound can facilitate the recog-nition of treatable causes of cardiac arrest (cardiactamponade, pneumothorax, massive pulmonary em-bolism, and severe left ventricular dysfunction) [29-31].

During the last few decades, the anesthesiologycommunity has demonstrated interest in the evaluationof left ventricular function in the perioperative period.The visual estimation of the left ventricular functionappears to be feasible, and previous studies haveshowed good correlation with formal transthoracicechocardiography by cardiology practitioners [32]. Thisinformation can be immediately available during thepre-anesthesia evaluation in patients that require urgentor emergency anesthesia care [2, 3]. Moreover, pa-tients with known systolic left ventricular dysfunctioncan be reassessed anytime they present with hemo-dynamic instability in the perioperative period.

Anesthesiologists frequently need to determine “fluidresponsiveness” in the clinical setting of perioperativearterial hypotension. Focused cardiac ultrasound,although not suitable for detecting fluid responsiveness(which requires measurement of cardiac output, beyondthe capability of focused cardiac ultrasound and per-taining to the Doppler echocardiography), is well suitedfor screening of severe hypovolemia, noninvasive

estimation of central venous pressure, and of systolicventricular function in patients who are spontaneouslybreathing. In this patient population, an IVC end-exhalation diameter lower than 1 cm and smallhyperdynamic right and left ventricles (the severehypovolemia “triad”) should receive fluids in the clinicalsetting of arterial hypotension, especially secondary totrauma or other states that involve hypovolemiapathophysiology (i.e., severe diarrhea, sepsis) [33].

In contrast, a more cautious interpretation of thisestimation must be taken into account for patientsreceiving mechanical ventilation because the naturaltendency of more distended IVC during the respiratorycycle and the variability of the abdominal-thoracicpressures interplay. Thus, no reliable IVC end-expira-tory size cutoffs are available in mechanical ventilation.Given the current inaccuracy of the end exhalationdiameter measurement, several studies demonstratethe usefulness of the distensibility index in passive (thepatient does not trigger the ventilator) mechanicallyventilated patients [5, 34, 35].

To date, there is scarce evidence to establish anassociation between the routine utilization of focusedcardiac ultrasound and improved perioperative out-comes. The expert consensus has been consideredinvaluable given the methodological limitations of arandomized trial. Despite this limitation, a much higherdiagnostic accuracy using focused cardiac ultrasoundhas been demonstrated. Jones et al. were able to findthe etiology of shock in 80% of patients with anultrasound-driven approach versus 50% (withoututilization of focused cardiac ultrasound) [22].

Cowie et al. has showed the usefulness of focusedcardiac ultrasound performed by anesthesiologists inthe perioperative period. Relatively common disorderssuch as aortic stenosis, mitral valve disease, andpulmonary hypertension, which have a direct impactin the anesthetic plan, were identified with thisperioperative approach. Up to 82% of patients requiredchanges in perioperative management based onfocused cardiac ultrasound. Finally, most of the majorfindings by anesthesiologists correlated (92% of patientevaluations) with formal comprehensive echocardio-gram examinations performed by cardiologists [36-38].

Another potential advantage of implementing FUSAis its utilization on some patients who can receive amore appropriate perioperative management of thesemedical conditions (i.e., patients with unknown poorLV function that require mechanical thrombectomy foracute ischemic stroke). Perioperative cardiac eventscan be predicted by the routine use of focused cardiacultrasound in noncardiac surgery [3].

Although these investigations have not shownimproved clinical outcomes, this approach certainlyfacilitates the perioperative management of potential


high-risk surgical patients. More recently, the early goaldirected therapy utilizing invasive monotoring to guidefluid resuscitation in septic patients has been questioned[39-41].

Moreover, there is a growing interest in the bettercharacterization of the cardiovascular profile of septicpatients under echocardiography. Preliminary evidencein the emergency department has hightlighted the valueof focused cardiac ultrasound in the suspicion, diagno-sis, and management of septic patients [42]. In summary,it seems quite reasonable to perform an initial ultra-sound-driven assessment of surgical patients with acutehemodynamic instability. With appropriate training,more standard utilization of this technology in theperioperative setting, and importantly, its noninvasivenature and widespread availability, there is no doubtthat perioperative outcomes can be dramaticallyimproved in high-risk patients.

In Figure 12, a practical and methodical approachto shock with FUSA is presented.

Lung ultrasound-driven approach to thesurgical patient in acute respiratorydistressInitial assessment of perioperative patients presenti-

ng with acute respiratory insufficiency or failure shouldinclude both cardiac and lung focused ultrasonography.Thus, both ultrasound examinations are complementaryin the characterization of acute respiratory failure(ARF). Furthermore, the value of this approach ismaximal when patients develop shock and ARF (seeFigures 12 and 13).

ConclusionsFocused cardiac and lung ultrasound in anesthesia

has gained acceptance among anesthesiologist andcritical care practitioners in the last decade. Its clinicalapplication has improved the diagnostic accuracy ofpotentially life-threatening conditions in the periope-rative period. Both modalities are complementary inthe evaluation of patients suffering from hemodynamicinstability or acute respiratory failure. In addition, thenoninvasive nature of these techniques, lack of radia-tion, and use of consumables makes it safer and morecost-effective for the timely care of surgical patients.However, there is need for more robust clinical evi-dence of clinical impact in patient care. Lastly, focusedcardiac and lung ultrasound for monitoring are far fromroutine use given the limited quantitative informationobtained with them. Thus, more advanced training isnecessary in order to achieve the most useful infor-mation from perioperative ultrasonography.Limitations of focused ultrasonography in

anesthesiaTransthoracic echocardiography can be difficult

under certain circumstances (e.g., patients with morbid

obesity, severe chronic lung disease, and/or chest walldeformity). Most patients have at least one “good echoview”, and at times, only one view is technicallyappropriate.

The anesthesia practitioner must also be aware ofrelevant limitations when applying lung ultrasonography.First, subcutaneous emphysema prevents theultrasound beam from reaching deeper structures(pleura). Other conditions that limit the ultrasoundexamination of the lung include previous pleurodesis,pleural calcifications, and the presence of chest tubes.Morbidly obese or edematous patients can also bedifficult to evaluate because a great dissipation ofultrasound energy occurs in the superficial layers.

Conflict of interestNothing to declare


Fig. 13. Synopsis of lung ultrasound semiotics. Main segmental patterns are illustrated (left column) and described in their distinctivefeatures (right column). Normal pattern (13A), sonographic interstitial syndrome (> 3 B-lines/intercostal space) (13C) and pneumothorax(1F) are mutually exclusive artefact-based patterns. Pleural sliding (13A) and lung pulse (13B) are representations of visceral pleuralmotion (in a ventilated and a non-ventilated lung area, respectively), and are here shown using M-Mode imaging as having a differentappearance of artefacts beyond the pleural line. M-Mode provides representation over time of reflected echoes from a single scanningline. Effusion (13C) and consolidation (13D) are image-based patterns. E: effusion; P: lung; L: liver; S: spleen; e: loculated effusion;asterisks indicate rib shadows) (modified with permission from Minerva Anesthesiol 2012; 78: 1282-1296)


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Ultrasonografia cardiopulmonară ţintită:implicaţii şi aplicabilitate în perioadaperioperatorie

RezumatUltrasonografia cardiopulmonară ţintită în anestezie

(FUSA) poate reprezenta atât un instrument diagnosticşi procedural, cât şi un instrument de monitorizare careeste de real folos în îngrijirea perioperatorie a pacienţilorchirurgicali. Utilizarea acestei metode este recomandatăîn practica anestezică şi de terapie intensivă. Deşi înprezent există bariere semnificative în utilizarea mai largăa metodei, dovezile privind utilitatea acesteia continuă săapară, astfel încât să asistăm la stabilirea ei ca standardde îngrijire în perioada perioperatorie.

În prezent, cele mai frecvente aplicaţii ale FUSA suntreprezentate de ghidarea şi descrierea şocului perioperator(cord pulmonar acut, insuficienţă ventriculară stângă,tamponadă cardiacă şi hipovolemie), precum şi de insufi-cienţa respiratorie acută (pneumotorace, edem pulmonaracut, colecţii pleurale masive, atelectazii masive).Acurateţea înaltă a diagnosticului în toate aceste situaţiiclinice face importantă utilizarea FUSA în perioadaperioperatorie. Mai mult decât atât, FUSA are aplicaţii şiîn alte sfere ale practicii anestezice, precum manage-mentul căii aeriene şi evaluarea conţinutului gastric înurgenţele chirurgicale.

Cuvinte cheie: ultrasonografie cardiacă ţintită,ultrasonografie pulmonară, şoc, hipoxemie

focused cardiac and lung ultrasonography: implications and

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