New Applications
of Two-Dimensional Transesophageal Cardiac Surgery
Echocardiography
in
K. Orihashi, MD, Y.W. Hong, MD, G. Chung, BA, D. Sisto, MD, P.L. Goldiner, MD, and Y. Oka, MD This articlo deacribes new applications
of two-dimensional
transesophageal echocardiography (PD-TEE). including (1) detection of pioural fluid (PF) and atelectasis (AT), and (2) evaiuation of verious cannulation techniques. The left and right pleura1 speces were visualized by rotating the probe counterclockwise and clockwise, respectivdy, from the fourchamber view. PF wes depicted es e crescent-shaped echofree space, enclosed by the lung and posterior chest wall on both sides. AT was often accompanied by PF and was depicted as a Iess echogenic area in the lung perenchyma. During removal of PF. the echo-free space gradually decreesed in size to tho point of diseppeering completely, while the lung parencbyma expanded end became more echogenic. TEE was advantageous in detecting PF and AT located in the most dorsal perts of the pleura1 space and lung perenchyma. The aorta acted as an acoustic window on the left side. TEE was found useful in evaluating the cannulae position of the
T
WO-DIMENSIONAL transesophageal echocardiography (2D-TEE) is being used increasingly in cardiac anesthesia for continuous monitoring of cardiac function’.’ and for evaluating surgical procedures.3.4 Recently, new applications of TEE have been developed that include detecting pleura1 fluid (PF) and atelectasis (AT) of the lung, and evaluating various cannulations for the intraaortic balloon pump (IABP), ventricular assist device (VAD), and cardiopulmonary bypass (CPB). In this report, the TEE techniques and echocardiographic findings of these applications are described. MATERIALS
AND METHODS
After induction of anesthesia and endotracheal intubation, a TEE probe (3.75 MHz, ESB-37LR; Toshiba, Tokyo, Japan) was inserted in the esophagus and connected to the echocardiographic system (SSH-65A, Toshiba, Tokyo, Japan). Studies were approved by the research committee of this institution. Informed consent was obtained from al1 patients. RESULTS
Detection of PF and AT Nonnal
Pleura1 Space
With the patient in a supine position, PF tends to stay at the dorsal and caudal portion of the pleura1 space; therefore, the examination was conducted at the leve1 just cephalad to the diaphragm. Figure 1C shows a schematic illustration of horizontal tomography of the thorax at this leve1 in a patient without PF. Cross-sectional views of horizontal planes are readily obtained by scanning from the esophagus. The two shadowed areas (L and R) represent the extent of visualization in examining the pleura1 space using TEE. In examining the pleura1 space, the TEE probe was inserted about 30 cm from the incisors in order to obtain the four-chamber view. The probe was Ekamination of the left pleura1 space. unlocked once and rotated counterclockwise in order to obtain the short-axis view of the descending aorta. Figure 1A shows a TEE of the left thorax without PF, correspondJournalof Cardiothoracic and VascularAnesfhesia,
intraeortic belloon pump (IABP) and ventriculer assist device (VAD), and femoral cannulae for cardiopuhnonery bypass (CPB). During use of the IABP, the chamber end shaft were visualized clearly and both malposition of the catheter tip and malfunction of the balloon were easily detected. For VAD, TEE reedily showed the collapse of the ventrfcular cavity due to excessive drainage of blood from the left ventricle, as wel1 as the favorable result of immediete reduction of flow rate. For femorofemoral extrecorporeel bypass, TEE detected improper position of the venous cannula. These new applications of TEE can be perfomwd with minimal manipulation of the probe, enablmg eerly detection of the problems and initiating timely and appropriate therapy. It is believed that the postoperative complicetions may be minimized. Copyright o 1991 by W.B. Saundars Company
ing to area L in Fig 1C. The aorta is shown in the near field and, to the right side of the aorta, the vertebrae are seen as arc-shaped strong echo with an acoustic shadow. The pleura1 space cannot be visualized because ultrasound was markedly reflected at the surface of the air-filled lung that was situated adjacent to the aorta. Examination of the right pleura1 space. The probe was rotated clockwise from the four-chamber view position. During rotation, the image of the right atrium in the four-chamber view moved to the right side of the screen and disappeared. However, the right pleura1 space could not be seen because the ultrasound was markedly reflected by the lung, which is located adjacent to the esophagus (Fig 1B). To examine the complete right pleura1 space, the probe was rotated until an image of the vertebra was encountered. The vertebrae were seen as a strong echo with acoustic shadow on the left of the screen. Pleura1 Space With Fluid
Figure 2C schematically illustrates horizontal tomography of the thorax in a patient with bilateral pleura1 fluid. The fluid on the dorsal side of the pleura1 space, with the patient in a supine position, is observed between the lung and the aorta on the left side and between the lung and esophagus on the right side. The lungs are pressed upward, ie, toward the anterior surface of the patient and, consequently, the lungs emerge toward the operative field. The two shadowed areas (L and R) in Fig 2C represent the extent of visualization in examining the pleura1 space using TEE.
From the Depatiments of Anesthesiology and Cardiothoracic gety, Albert Einstein College of MedicinelMontejìore Medical
Sur-
Center,
Bronx, NY.
Address reprint requests to Yasu Oka, MD, Department ofAnesthesiology (F-726S), Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, Ny 10461. Copyright 0 1991 by WB. Saunders Company 1053-0770/91/0501-0007$03.00l0
Vol 5, NO 1 (February), 1991: pp 33-39
33
ORIHASHI
ET AL
Fig 1. IA) TEE corresponding to view L in Fig 1C. The aorta is seen in the near field. Image in the far field cannot be obtained due to marked reflection end attenuation of ultrasound at the surfsce of the lung; (B) corresponding to view R in Fig 1C. The entire image is blurred by reflection of ultrasound at the lung surface adjacent to the esophagus. V, vertebra; AS, acoustic shadow caused by the vertebra; SL, side lobe caused by the lung. (Cj Schematic illustration of horizontal tomography of the thorax at the leve1 just above the diaphragm for observing the pleura1 space by TEE. Two shadowed areas (L and R) indicate the extern of visualization by TEE in examining the pleura1 spaces. Ao, aorta; E, esophagus; V, vertebra.
Figure 2A is a TEE showing left PF, obtained in the same manner described. It showed a crescent-shaped, echo-free space, originating in the paraaortic region and extending to the far field. The echo-free space was enclosed by the aorta, lung, and posterior chest wall. The largest echo-free space was obtained when the probe was advanced a few centimeters from the initial level. Figure 2B is a TEE showing right PF. This view corresponds to the shadowed area R in Fig 2C. The fluid found on the right side was depicted as a crescent-shaped, echo-free space adjacent to the transducer (top of the screen) enclosed by the lung and posterior chest wall. The largest echo-free space was obtained when the probe was advanced 1 to 2 cm, but before the liver appeared on the screen. AT of the Lungs In the lung parenchyma situated close to the PF, very weak reflection and minima1 attenuation of ultrasound were present. The images of the lung parenchyma (Figs 2A and 2B) resembled the consolidated image of the liver, thus indicating little or no air content in the alveoli (ie, AT). This was best seen in the most dorsal and caudal portion of the lung in the patient lying in the supine position.
The lung parenchyma farther away from the fluid created strong reflections of ultrasound, and images could not be obtained in the far field (on the left in Fig 2A and on the right in Fig 2B). This implied that this portion of the lung had alveoli containing air. Removal of the Fluid In al1 patients with a detectable echo-free space, the surgeons confirmed the presence of PF, which was then removed by suction. The suction catheter was depicted as a strong echo with acoustic shadow in the echo-free space, and chest tubes as double parallel lines of strong ethos. During the removal of PF, the echo-free space decreased in size and then disappeared, while the lung parenchyma gradually expanded and completely replaced the echo-free space. At the same time, the lung became more echogenic and showed a normal appearance. However, in some patients, dorsal lung parenchyma remained atelectatic even after the lung was hyperinflated (Fig 3). Evaluation
of Cannulation
TEE Techniques With ZABP Figure 4 schematically illustrates an IABP catheter with the tip position at the correct level, 3 to 4 cm below the base
NEW APPLICATIONS OF TEE
Fig 2. TEE showing fluid in the pieural space. (A) corresponding to view L in Fig X. The ff ls visuai)zed through the descendhtg aorta as an echofree space, enciosed by the iung, aorta, and posterior chest wall. The areas of lung close to the fluld (donal portion) are atelectatic and are seen in the center of the screen. On the Ieft side of the screen, iess ateleatatk iung parenchyma is seen as a strong echo: AiR(+ +). (B) correaponding to vlew ff in Flg 2C. The fiuid is seen as a crescent-shaped, bfree spaca in the center of the screen, enclosad by the lung and posterlor chest waii. The dorsal portlon of the lung adjacent to the fhdd is atelectatic; V, vertebra. (C) Bchematic iilustration of horizontai tomography of the thorax with bllateral PF retention. The fluid (F) stays on the dorsal side, pushes the lung ventrally (solid ?? rrows), and intervenes between the lung and the aorta on the laft and the esophagus on tha right (smal1 arrows). The iung rises toward the opemtfve field (hollow anows). The dark area indicates atoiectatic lung parenchyrna. Areas L and R represent the extent of visualiration in examlning the pleura1 spaca by TEE.
Fig 3. TBE foiiowing removal of PF. corresponding to Fig 2A. Although the echo-free space dlsappeared and the lung expanded, some AT remafned. The posterlor drast wal1 is seen through the atelectatk lung because there is minima1 reflection and attenuation of ultrasound.
R
of the left subclavian artery (SCA). The aortic arch gives off the left SCA from its superior aspect. The esophagus runs along the descending aorta and sequentia1 cross-sectional views of the aorta can be obtained using TEE. Four scanning levels for observing the aorta and the IABP catheter (levels A to D) are shown. The short-axis view of the descending aorta was obtained at the leve1 of the four-chamber view. The chamber portion of the IABP catheter was visualized at this level, corresponding to leve1 A in Fig 4. The chamber was depicted in the aorta as an rhythmically moving echogenic image. In Fig 4A, a strong echo density was observed while the balloon was deflated (left). At the moment of inflation (right), a scattered echo filled the aorta. As the TEE probe was withdrawn, the image of the IABP chamber was replaced by the image of the balloon shaft, resembling the image of the chamber portion during deflation. This was shown as a strong echo dot with a side lobe (Fig 4B), corresponding to leve1 B. Further withdrawal of the TEE probe to leve1 C visualized the descending aorta
36
ORIHASHI
T
ET AL
E
D C Cephalad
B
A Ventral -t Caudal
Fii 4.
Schematic illustration of four of the sequentia1 scanning planes of the thoracic descending aorta and the aortic arch obtained by TEE. The runs along the side ofthe descendlng aorta and sequentia1 views of the aorta can be obtained by rotating the probe clockwise, as it is withdrawn. A to D indicate four Ieveis of those sequentia1 TEE views. (A) Leve1 of IABP chamber. At deflation, the catheter is seen as a dot of strong echo 4th a side lobe (SL) @ft). At infletion, scattered echo fills the aortic lumen (right). (B) Leve1 of IABP catheter. The catheter (CATH) is depiaed as a dot of strong echo, accompanied with a side lobe. (C) Leve1 of the descending aorta without catheter. (D) Leve1 of aortic arch (ARCH). T, rrachea.
esophagus
proximal to the catheter tip (Fig 4C). More superiorly, the aortic arch was depicted in the long-axis view (Fig 4D). Figure 5 shows the IABP catheter in the aorta at the leve1 of the aortic arch in a short female patient. This abnormally high position was confirmed by chest x-ray and led to proper repositioning of the IABP catheter. TEE Techniques Wïth VAD Different types of VAD are able to maintain blood flow regardless of the patient’s cardiac output. Their application
is useful in cardiogenic shock when patients cannot be separated from CPB and have failed to respond to the IABP. Cannulation of the aorta, pulmonary artery, left atrium or ventricle (LV), and right atrium is performed with cannulae connected to different types of blood pumps. TEE was used to monitor a patient placed on both left and right VADs. It was able to depict the LV cannula as a strong echo with a side lobe close to the ventricular septum in both short- and long-axis views (Fig 6). Ten minutes after the initiation of VAD, the LV cavity became very small,
NEW APPLICATIONS OF TEE
Fig 5. TEE rhowlng the catheter tip at the leve1 of the aortic arch, indkating too high a posltion of the tip. Melposition of the catheter tip was confirmed by the postoperative chest x-ray. ARCH, aortic arch; CATH. catheter.
Fig 7. TEE of rhott-axis view of LV et end-diastok, rhowing the LV cannula (CATH) sucking against the pepillary mus& (PM) on VAD at the flow rate of 5.5 L/min for 10 minutes. The LV cavity is small.
causing a portion of the papillary muscle to be sucked into the drainage holes of the LV cannula (Fig 7). The VAD flow was immediately reduced and volume infusion was begun. This resulted in the enlargement of the LV cavity and disengagement of the papillary muscle from the cannula. The maintenance of a satisfactory flow through the VAD requires good drainage of blood by the right and left drainage cannulae. In this case, it was possible to demonstrate that, in spite of a satisfactory left atria1 pressure (LAP), collapse of the LV cavity around the cannula occurred. This can cause both reduction of the drainage and endocardial trauma.
TEE was used with venous cannulation for a patient undergoing third-time CABG. With the four-chamber view by TEE soon after the cannulation, the venous cannula was observed as a double set of echogenic lines. The cannula was found to be pushing on the interatrial septum and impinging on the left atria1 cavity (Fig 8, left). Although there was no difficulty in draining blood from the patient at that time, the cannula was promptly withdrawn to a more proper, lower position. After this maneuver, the cannula was observed at the junction of the right atrium and the inferior vena cava (Fig 8, right). TEE detected the improper position of the venous cannula in this patient. Trauma to the atria1 septum and the possibility of poor venous drainage were avoided before the institution of full CPB.
TEE Techniques With CPB Femorofemoral extracorporeal bypass can be instituted during difficult repeat operations and during repair of a descending thoracic aortic aneurysm. The venous drainage is obtained from a cannula advanced up to the right atrium over a wire. Poor positioning of the cannula is associated with poor venous return.
Fig 6. TEE showing the cannula in the LV neer the ventrlcular septum in the short-axls (Ieft) and long-axls view (right) at enddiastole. The cannula (CATH) is depicted es a streng echo with a side lobe (SL). RV, right ventricle; LA, Ieft atrium.
DISCUSSION
Preoperatively, a pleura1 effision may be present in patients with congestive heart failure.5 In other patients, fluid may accumulate intraoperatively because of (1) bleeding caused by dissection of the internal mammary artery (MA); (2) persistent bleeding from the dissection site after heparin administration; or (3) collection of irrigation fluid. The authors’ initial recognition of the presence of PF was incidental. During the next 2 months, PF was found in eight patients and the TEE techniques for examining PF were established. By TEE, fluid in the pleura1 space is visualized as an echo-free space. The echo-free space may contain echogenic dots of different sizes and densities when this huid contains blood clots or debris. These findings correspond to those with PF or hemothorax observed with conventional ultrasonography.6 TEE is advantageous in detecting fluid located in the most dorsal part of the pleura1 space. When a smal1 amount of fluid is present in the pleura1 space, it accumulates first in the most dorsal portion of the patient. With increasingly greater amounts of fluid, it intervenes between the lung and chest wall, and then reaches the aorta on the left side and
38
ORIHASHI
Fig 8. TEE showing the venous cannula tip pressing the intraatrial septum (IAS) toward the left atrium (LA) [left). The cannula is depicted as a double strong echo with a side lobe. The cannula tip was repositioned to the junction of the right atrium (RA) and inferior vena cava by withdrawing the cannula by 2 to 3 cm (right).
the esophagus on the right side of the chest. The aorta is very helpful in visualizing the fluid located in the most dorsal portion of the left pleura1 space because it acts as an acoustic window. However, on the right side it is more difficult to detect PF because there is no acoustic window like the aorta. It appears that fluid needs to accumulate to the leve1 of the esophagus to be detected by TEE. The largest echo-free space is usually observed when the TEE transducer is advanced 2 to 3 cm from the leve1 of the four-chamber view and positioned just cephalad to the diaphragm. This is the best leve1 for examining for the presence of bilateral PF. Although the surgeons were able to confirm the presence of pleura1 fluid in al1 patients in whom an echo-free space was detected, the most dorsal part of the pleura1 space is a blind zone for surgeons. During routine cardiac surgery, opening the pleura to determine the presence of PF is not frequently performed, and if the pleura is opened for IMA dissection, frequent inspection of the dorsal pleura1 space by lifting the lung is not usually performed because of the possible hemodynamic derangements. TEE is the only noninvasive method for intraoperative detection of PF. In addition, unnecessary exploration of the pleura1 space in the early postoperative period can be avoided. When the lungs are pushed up into the operative field due to the unrecognized PF and interfere with the operative procedure, anesthesiologists tend to reduce the tidal volume. However, this may lead to a further AT in already partially atelectatic lungs. Because intraoperative development of AT associated with the PF can be minimized by
ET AL
early detection, it is important to search for the presence of PF prior to decreasing the tidal volume. In one patient, the echo-free space at the dorsal portion of the lung did not decrease in spite of an effort to remove the fluid by a suction catheter. The position of the suction catheter was adjusted further posteriorly with echo guidante and the fluid was successfully removed. Therefore, TEE may also be used for detecting malposition of chest tubes intraoperatively, which may cause improper drainage of the accumulated blood or fluid and may expose the patient to the increased risk of thoracocentesis in the postoperative period. Further studies are needed to examine (1) the incidence of fluid retention and associated AT in the cardiac surgical patients; (2) quantitative measurement of the PF related to TEE findings; and (3) the relationship among fluid retention, atelectasis, and the postoperative hypoxia and ventilation problems. Although an IABP is often instituted during cardiac surgery, complications are not uncommon.‘,’ TEE is a valuable tooi that allows anesthesiologists and surgeons to examine the optimal placement of the IABP catheter intraoperatively, because it can be visualized clearly in the descending aorta. Intraoperative blind insertion of the IABP catheter can lead to high or low positioning of the catheter tip, which may not be recognized until a postoperative chest x-ray is obtained. A catheter tip advanced too far could reach the aortic arch and cause trauma, whereas a catheter too low in the descending aorta can cause poor diastolic augmentation and impairment of the renal blood flow. Using TEE, the pssition of the catheter tip can be confirmed at the correct leve1 of the descending aorta by its echocardiographic image. After instituting counterpulsation, the pulsatile motion of the balloon in the aorta can be readily visualized by TEE. Incomplete balloon expansion or catheter kinking can be immediately confirmed and the appropriate measures taken. Aortic wal1 trauma or even dissection, although rare, can be seen as a catastrophic complication of IABP insertion. TEE can readily visualize aortic dissection.’ Fortunately, the authors have not experienced this complication, but believe it is a good idea to check the aorta for dissection after intraoperative insertion of the IABP catheter. In conclusion, 2D-TEE is a useful tool for detecting the presence of PF and AT, and for evaluating the positions of various cannulae. These new applications of TEE can be performed with minima1 manipulations of the TEE probe from the conventional long-axis view of the heart. Early detection of a problem permits appropriate therapy in an effort to minimize postoperative complications.
REFERENCES
1. Smith JS, Cahalan MK, Benefiel DJ, et al: Intraoperative detection of myocardial ischemia in high-risk patients: Electrocardiography versus two-dimensional transesophageal echocardiography. Circulation 72:1015-1021,1985 2. Clements M, de Bruijn NP: Perioperative evaluation of regional wal1 motion by transesophageal two-dimensional echocardiography. Anesth Analg 66:249-261, 1987
3. Gxgrove DM, Stewart WJ: Intraoperative function. Curr Probl Cardiol 14:388-393,1989 4. Kyo S, Takamoto S, Adachi tion of repair of aortic dissection: Cardiac Imaging 4:49-50, 1989 5. Light RW: Pleura1
effusion,
evaluation
of valve
H, et al: Intraoperative evaluaSurgical decision-making. Int J
in Murray
JF, Nadel
JA (eds):
NEW APPLICATIONS
OF TEE
Textbook of Respiratory Medicine. Philadelphia, PA, Saunders, 1988, pp 1719-1744 6. Greenspan RH, Mann H: Ultrasound, in Murray JF, Nadel JA (eds): Textbook of Respiratory Medicine. Philadelphia, PA, Saunders, 1988, pp 521-524 7. McEnany MT, Kay HR, Buckley MJ, et al: Clinical experience with intraaortic balloon pump support in 728 patients. Circulation 58:124-132,1978 (suppl1)
39
8. Daily EK, Tilkian AG: Intra-aortic balloon pumping, in Tilkian AG, Daily EK (eds): Cardiovascular ProceduresDiagnostic Techniques and Therapeutic Procedures. St Louis, MO, Mosby, 1986, pp 257-273 9. Erbel R, Börner N, Steller D, et al: Detection of aortic dissection by transesophageal echocardiography. Br Heart J 58:4551,1987
of Two-Dimensional Transesophageal Cardiac Surgery
Echocardiography
in
K. Orihashi, MD, Y.W. Hong, MD, G. Chung, BA, D. Sisto, MD, P.L. Goldiner, MD, and Y. Oka, MD This articlo deacribes new applications
of two-dimensional
transesophageal echocardiography (PD-TEE). including (1) detection of pioural fluid (PF) and atelectasis (AT), and (2) evaiuation of verious cannulation techniques. The left and right pleura1 speces were visualized by rotating the probe counterclockwise and clockwise, respectivdy, from the fourchamber view. PF wes depicted es e crescent-shaped echofree space, enclosed by the lung and posterior chest wall on both sides. AT was often accompanied by PF and was depicted as a Iess echogenic area in the lung perenchyma. During removal of PF. the echo-free space gradually decreesed in size to tho point of diseppeering completely, while the lung parencbyma expanded end became more echogenic. TEE was advantageous in detecting PF and AT located in the most dorsal perts of the pleura1 space and lung perenchyma. The aorta acted as an acoustic window on the left side. TEE was found useful in evaluating the cannulae position of the
T
WO-DIMENSIONAL transesophageal echocardiography (2D-TEE) is being used increasingly in cardiac anesthesia for continuous monitoring of cardiac function’.’ and for evaluating surgical procedures.3.4 Recently, new applications of TEE have been developed that include detecting pleura1 fluid (PF) and atelectasis (AT) of the lung, and evaluating various cannulations for the intraaortic balloon pump (IABP), ventricular assist device (VAD), and cardiopulmonary bypass (CPB). In this report, the TEE techniques and echocardiographic findings of these applications are described. MATERIALS
AND METHODS
After induction of anesthesia and endotracheal intubation, a TEE probe (3.75 MHz, ESB-37LR; Toshiba, Tokyo, Japan) was inserted in the esophagus and connected to the echocardiographic system (SSH-65A, Toshiba, Tokyo, Japan). Studies were approved by the research committee of this institution. Informed consent was obtained from al1 patients. RESULTS
Detection of PF and AT Nonnal
Pleura1 Space
With the patient in a supine position, PF tends to stay at the dorsal and caudal portion of the pleura1 space; therefore, the examination was conducted at the leve1 just cephalad to the diaphragm. Figure 1C shows a schematic illustration of horizontal tomography of the thorax at this leve1 in a patient without PF. Cross-sectional views of horizontal planes are readily obtained by scanning from the esophagus. The two shadowed areas (L and R) represent the extent of visualization in examining the pleura1 space using TEE. In examining the pleura1 space, the TEE probe was inserted about 30 cm from the incisors in order to obtain the four-chamber view. The probe was Ekamination of the left pleura1 space. unlocked once and rotated counterclockwise in order to obtain the short-axis view of the descending aorta. Figure 1A shows a TEE of the left thorax without PF, correspondJournalof Cardiothoracic and VascularAnesfhesia,
intraeortic belloon pump (IABP) and ventriculer assist device (VAD), and femoral cannulae for cardiopuhnonery bypass (CPB). During use of the IABP, the chamber end shaft were visualized clearly and both malposition of the catheter tip and malfunction of the balloon were easily detected. For VAD, TEE reedily showed the collapse of the ventrfcular cavity due to excessive drainage of blood from the left ventricle, as wel1 as the favorable result of immediete reduction of flow rate. For femorofemoral extrecorporeel bypass, TEE detected improper position of the venous cannula. These new applications of TEE can be perfomwd with minimal manipulation of the probe, enablmg eerly detection of the problems and initiating timely and appropriate therapy. It is believed that the postoperative complicetions may be minimized. Copyright o 1991 by W.B. Saundars Company
ing to area L in Fig 1C. The aorta is shown in the near field and, to the right side of the aorta, the vertebrae are seen as arc-shaped strong echo with an acoustic shadow. The pleura1 space cannot be visualized because ultrasound was markedly reflected at the surface of the air-filled lung that was situated adjacent to the aorta. Examination of the right pleura1 space. The probe was rotated clockwise from the four-chamber view position. During rotation, the image of the right atrium in the four-chamber view moved to the right side of the screen and disappeared. However, the right pleura1 space could not be seen because the ultrasound was markedly reflected by the lung, which is located adjacent to the esophagus (Fig 1B). To examine the complete right pleura1 space, the probe was rotated until an image of the vertebra was encountered. The vertebrae were seen as a strong echo with acoustic shadow on the left of the screen. Pleura1 Space With Fluid
Figure 2C schematically illustrates horizontal tomography of the thorax in a patient with bilateral pleura1 fluid. The fluid on the dorsal side of the pleura1 space, with the patient in a supine position, is observed between the lung and the aorta on the left side and between the lung and esophagus on the right side. The lungs are pressed upward, ie, toward the anterior surface of the patient and, consequently, the lungs emerge toward the operative field. The two shadowed areas (L and R) in Fig 2C represent the extent of visualization in examining the pleura1 space using TEE.
From the Depatiments of Anesthesiology and Cardiothoracic gety, Albert Einstein College of MedicinelMontejìore Medical
Sur-
Center,
Bronx, NY.
Address reprint requests to Yasu Oka, MD, Department ofAnesthesiology (F-726S), Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, Ny 10461. Copyright 0 1991 by WB. Saunders Company 1053-0770/91/0501-0007$03.00l0
Vol 5, NO 1 (February), 1991: pp 33-39
33
ORIHASHI
ET AL
Fig 1. IA) TEE corresponding to view L in Fig 1C. The aorta is seen in the near field. Image in the far field cannot be obtained due to marked reflection end attenuation of ultrasound at the surfsce of the lung; (B) corresponding to view R in Fig 1C. The entire image is blurred by reflection of ultrasound at the lung surface adjacent to the esophagus. V, vertebra; AS, acoustic shadow caused by the vertebra; SL, side lobe caused by the lung. (Cj Schematic illustration of horizontal tomography of the thorax at the leve1 just above the diaphragm for observing the pleura1 space by TEE. Two shadowed areas (L and R) indicate the extern of visualization by TEE in examining the pleura1 spaces. Ao, aorta; E, esophagus; V, vertebra.
Figure 2A is a TEE showing left PF, obtained in the same manner described. It showed a crescent-shaped, echo-free space, originating in the paraaortic region and extending to the far field. The echo-free space was enclosed by the aorta, lung, and posterior chest wall. The largest echo-free space was obtained when the probe was advanced a few centimeters from the initial level. Figure 2B is a TEE showing right PF. This view corresponds to the shadowed area R in Fig 2C. The fluid found on the right side was depicted as a crescent-shaped, echo-free space adjacent to the transducer (top of the screen) enclosed by the lung and posterior chest wall. The largest echo-free space was obtained when the probe was advanced 1 to 2 cm, but before the liver appeared on the screen. AT of the Lungs In the lung parenchyma situated close to the PF, very weak reflection and minima1 attenuation of ultrasound were present. The images of the lung parenchyma (Figs 2A and 2B) resembled the consolidated image of the liver, thus indicating little or no air content in the alveoli (ie, AT). This was best seen in the most dorsal and caudal portion of the lung in the patient lying in the supine position.
The lung parenchyma farther away from the fluid created strong reflections of ultrasound, and images could not be obtained in the far field (on the left in Fig 2A and on the right in Fig 2B). This implied that this portion of the lung had alveoli containing air. Removal of the Fluid In al1 patients with a detectable echo-free space, the surgeons confirmed the presence of PF, which was then removed by suction. The suction catheter was depicted as a strong echo with acoustic shadow in the echo-free space, and chest tubes as double parallel lines of strong ethos. During the removal of PF, the echo-free space decreased in size and then disappeared, while the lung parenchyma gradually expanded and completely replaced the echo-free space. At the same time, the lung became more echogenic and showed a normal appearance. However, in some patients, dorsal lung parenchyma remained atelectatic even after the lung was hyperinflated (Fig 3). Evaluation
of Cannulation
TEE Techniques With ZABP Figure 4 schematically illustrates an IABP catheter with the tip position at the correct level, 3 to 4 cm below the base
NEW APPLICATIONS OF TEE
Fig 2. TEE showing fluid in the pieural space. (A) corresponding to view L in Fig X. The ff ls visuai)zed through the descendhtg aorta as an echofree space, enciosed by the iung, aorta, and posterior chest wall. The areas of lung close to the fluld (donal portion) are atelectatic and are seen in the center of the screen. On the Ieft side of the screen, iess ateleatatk iung parenchyma is seen as a strong echo: AiR(+ +). (B) correaponding to vlew ff in Flg 2C. The fiuid is seen as a crescent-shaped, bfree spaca in the center of the screen, enclosad by the lung and posterlor chest waii. The dorsal portlon of the lung adjacent to the fhdd is atelectatic; V, vertebra. (C) Bchematic iilustration of horizontai tomography of the thorax with bllateral PF retention. The fluid (F) stays on the dorsal side, pushes the lung ventrally (solid ?? rrows), and intervenes between the lung and the aorta on the laft and the esophagus on tha right (smal1 arrows). The iung rises toward the opemtfve field (hollow anows). The dark area indicates atoiectatic lung parenchyrna. Areas L and R represent the extent of visualiration in examlning the pleura1 spaca by TEE.
Fig 3. TBE foiiowing removal of PF. corresponding to Fig 2A. Although the echo-free space dlsappeared and the lung expanded, some AT remafned. The posterlor drast wal1 is seen through the atelectatk lung because there is minima1 reflection and attenuation of ultrasound.
R
of the left subclavian artery (SCA). The aortic arch gives off the left SCA from its superior aspect. The esophagus runs along the descending aorta and sequentia1 cross-sectional views of the aorta can be obtained using TEE. Four scanning levels for observing the aorta and the IABP catheter (levels A to D) are shown. The short-axis view of the descending aorta was obtained at the leve1 of the four-chamber view. The chamber portion of the IABP catheter was visualized at this level, corresponding to leve1 A in Fig 4. The chamber was depicted in the aorta as an rhythmically moving echogenic image. In Fig 4A, a strong echo density was observed while the balloon was deflated (left). At the moment of inflation (right), a scattered echo filled the aorta. As the TEE probe was withdrawn, the image of the IABP chamber was replaced by the image of the balloon shaft, resembling the image of the chamber portion during deflation. This was shown as a strong echo dot with a side lobe (Fig 4B), corresponding to leve1 B. Further withdrawal of the TEE probe to leve1 C visualized the descending aorta
36
ORIHASHI
T
ET AL
E
D C Cephalad
B
A Ventral -t Caudal
Fii 4.
Schematic illustration of four of the sequentia1 scanning planes of the thoracic descending aorta and the aortic arch obtained by TEE. The runs along the side ofthe descendlng aorta and sequentia1 views of the aorta can be obtained by rotating the probe clockwise, as it is withdrawn. A to D indicate four Ieveis of those sequentia1 TEE views. (A) Leve1 of IABP chamber. At deflation, the catheter is seen as a dot of strong echo 4th a side lobe (SL) @ft). At infletion, scattered echo fills the aortic lumen (right). (B) Leve1 of IABP catheter. The catheter (CATH) is depiaed as a dot of strong echo, accompanied with a side lobe. (C) Leve1 of the descending aorta without catheter. (D) Leve1 of aortic arch (ARCH). T, rrachea.
esophagus
proximal to the catheter tip (Fig 4C). More superiorly, the aortic arch was depicted in the long-axis view (Fig 4D). Figure 5 shows the IABP catheter in the aorta at the leve1 of the aortic arch in a short female patient. This abnormally high position was confirmed by chest x-ray and led to proper repositioning of the IABP catheter. TEE Techniques Wïth VAD Different types of VAD are able to maintain blood flow regardless of the patient’s cardiac output. Their application
is useful in cardiogenic shock when patients cannot be separated from CPB and have failed to respond to the IABP. Cannulation of the aorta, pulmonary artery, left atrium or ventricle (LV), and right atrium is performed with cannulae connected to different types of blood pumps. TEE was used to monitor a patient placed on both left and right VADs. It was able to depict the LV cannula as a strong echo with a side lobe close to the ventricular septum in both short- and long-axis views (Fig 6). Ten minutes after the initiation of VAD, the LV cavity became very small,
NEW APPLICATIONS OF TEE
Fig 5. TEE rhowlng the catheter tip at the leve1 of the aortic arch, indkating too high a posltion of the tip. Melposition of the catheter tip was confirmed by the postoperative chest x-ray. ARCH, aortic arch; CATH. catheter.
Fig 7. TEE of rhott-axis view of LV et end-diastok, rhowing the LV cannula (CATH) sucking against the pepillary mus& (PM) on VAD at the flow rate of 5.5 L/min for 10 minutes. The LV cavity is small.
causing a portion of the papillary muscle to be sucked into the drainage holes of the LV cannula (Fig 7). The VAD flow was immediately reduced and volume infusion was begun. This resulted in the enlargement of the LV cavity and disengagement of the papillary muscle from the cannula. The maintenance of a satisfactory flow through the VAD requires good drainage of blood by the right and left drainage cannulae. In this case, it was possible to demonstrate that, in spite of a satisfactory left atria1 pressure (LAP), collapse of the LV cavity around the cannula occurred. This can cause both reduction of the drainage and endocardial trauma.
TEE was used with venous cannulation for a patient undergoing third-time CABG. With the four-chamber view by TEE soon after the cannulation, the venous cannula was observed as a double set of echogenic lines. The cannula was found to be pushing on the interatrial septum and impinging on the left atria1 cavity (Fig 8, left). Although there was no difficulty in draining blood from the patient at that time, the cannula was promptly withdrawn to a more proper, lower position. After this maneuver, the cannula was observed at the junction of the right atrium and the inferior vena cava (Fig 8, right). TEE detected the improper position of the venous cannula in this patient. Trauma to the atria1 septum and the possibility of poor venous drainage were avoided before the institution of full CPB.
TEE Techniques With CPB Femorofemoral extracorporeal bypass can be instituted during difficult repeat operations and during repair of a descending thoracic aortic aneurysm. The venous drainage is obtained from a cannula advanced up to the right atrium over a wire. Poor positioning of the cannula is associated with poor venous return.
Fig 6. TEE showing the cannula in the LV neer the ventrlcular septum in the short-axls (Ieft) and long-axls view (right) at enddiastole. The cannula (CATH) is depicted es a streng echo with a side lobe (SL). RV, right ventricle; LA, Ieft atrium.
DISCUSSION
Preoperatively, a pleura1 effision may be present in patients with congestive heart failure.5 In other patients, fluid may accumulate intraoperatively because of (1) bleeding caused by dissection of the internal mammary artery (MA); (2) persistent bleeding from the dissection site after heparin administration; or (3) collection of irrigation fluid. The authors’ initial recognition of the presence of PF was incidental. During the next 2 months, PF was found in eight patients and the TEE techniques for examining PF were established. By TEE, fluid in the pleura1 space is visualized as an echo-free space. The echo-free space may contain echogenic dots of different sizes and densities when this huid contains blood clots or debris. These findings correspond to those with PF or hemothorax observed with conventional ultrasonography.6 TEE is advantageous in detecting fluid located in the most dorsal part of the pleura1 space. When a smal1 amount of fluid is present in the pleura1 space, it accumulates first in the most dorsal portion of the patient. With increasingly greater amounts of fluid, it intervenes between the lung and chest wall, and then reaches the aorta on the left side and
38
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Fig 8. TEE showing the venous cannula tip pressing the intraatrial septum (IAS) toward the left atrium (LA) [left). The cannula is depicted as a double strong echo with a side lobe. The cannula tip was repositioned to the junction of the right atrium (RA) and inferior vena cava by withdrawing the cannula by 2 to 3 cm (right).
the esophagus on the right side of the chest. The aorta is very helpful in visualizing the fluid located in the most dorsal portion of the left pleura1 space because it acts as an acoustic window. However, on the right side it is more difficult to detect PF because there is no acoustic window like the aorta. It appears that fluid needs to accumulate to the leve1 of the esophagus to be detected by TEE. The largest echo-free space is usually observed when the TEE transducer is advanced 2 to 3 cm from the leve1 of the four-chamber view and positioned just cephalad to the diaphragm. This is the best leve1 for examining for the presence of bilateral PF. Although the surgeons were able to confirm the presence of pleura1 fluid in al1 patients in whom an echo-free space was detected, the most dorsal part of the pleura1 space is a blind zone for surgeons. During routine cardiac surgery, opening the pleura to determine the presence of PF is not frequently performed, and if the pleura is opened for IMA dissection, frequent inspection of the dorsal pleura1 space by lifting the lung is not usually performed because of the possible hemodynamic derangements. TEE is the only noninvasive method for intraoperative detection of PF. In addition, unnecessary exploration of the pleura1 space in the early postoperative period can be avoided. When the lungs are pushed up into the operative field due to the unrecognized PF and interfere with the operative procedure, anesthesiologists tend to reduce the tidal volume. However, this may lead to a further AT in already partially atelectatic lungs. Because intraoperative development of AT associated with the PF can be minimized by
ET AL
early detection, it is important to search for the presence of PF prior to decreasing the tidal volume. In one patient, the echo-free space at the dorsal portion of the lung did not decrease in spite of an effort to remove the fluid by a suction catheter. The position of the suction catheter was adjusted further posteriorly with echo guidante and the fluid was successfully removed. Therefore, TEE may also be used for detecting malposition of chest tubes intraoperatively, which may cause improper drainage of the accumulated blood or fluid and may expose the patient to the increased risk of thoracocentesis in the postoperative period. Further studies are needed to examine (1) the incidence of fluid retention and associated AT in the cardiac surgical patients; (2) quantitative measurement of the PF related to TEE findings; and (3) the relationship among fluid retention, atelectasis, and the postoperative hypoxia and ventilation problems. Although an IABP is often instituted during cardiac surgery, complications are not uncommon.‘,’ TEE is a valuable tooi that allows anesthesiologists and surgeons to examine the optimal placement of the IABP catheter intraoperatively, because it can be visualized clearly in the descending aorta. Intraoperative blind insertion of the IABP catheter can lead to high or low positioning of the catheter tip, which may not be recognized until a postoperative chest x-ray is obtained. A catheter tip advanced too far could reach the aortic arch and cause trauma, whereas a catheter too low in the descending aorta can cause poor diastolic augmentation and impairment of the renal blood flow. Using TEE, the pssition of the catheter tip can be confirmed at the correct leve1 of the descending aorta by its echocardiographic image. After instituting counterpulsation, the pulsatile motion of the balloon in the aorta can be readily visualized by TEE. Incomplete balloon expansion or catheter kinking can be immediately confirmed and the appropriate measures taken. Aortic wal1 trauma or even dissection, although rare, can be seen as a catastrophic complication of IABP insertion. TEE can readily visualize aortic dissection.’ Fortunately, the authors have not experienced this complication, but believe it is a good idea to check the aorta for dissection after intraoperative insertion of the IABP catheter. In conclusion, 2D-TEE is a useful tool for detecting the presence of PF and AT, and for evaluating the positions of various cannulae. These new applications of TEE can be performed with minima1 manipulations of the TEE probe from the conventional long-axis view of the heart. Early detection of a problem permits appropriate therapy in an effort to minimize postoperative complications.
REFERENCES
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3. Gxgrove DM, Stewart WJ: Intraoperative function. Curr Probl Cardiol 14:388-393,1989 4. Kyo S, Takamoto S, Adachi tion of repair of aortic dissection: Cardiac Imaging 4:49-50, 1989 5. Light RW: Pleura1
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NEW APPLICATIONS
OF TEE
Textbook of Respiratory Medicine. Philadelphia, PA, Saunders, 1988, pp 1719-1744 6. Greenspan RH, Mann H: Ultrasound, in Murray JF, Nadel JA (eds): Textbook of Respiratory Medicine. Philadelphia, PA, Saunders, 1988, pp 521-524 7. McEnany MT, Kay HR, Buckley MJ, et al: Clinical experience with intraaortic balloon pump support in 728 patients. Circulation 58:124-132,1978 (suppl1)
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8. Daily EK, Tilkian AG: Intra-aortic balloon pumping, in Tilkian AG, Daily EK (eds): Cardiovascular ProceduresDiagnostic Techniques and Therapeutic Procedures. St Louis, MO, Mosby, 1986, pp 257-273 9. Erbel R, Börner N, Steller D, et al: Detection of aortic dissection by transesophageal echocardiography. Br Heart J 58:4551,1987
