TRANS ESOPHAGEAL ECHOCARDIOGRAPHY

TRANS ESOPHAGEAL ECHOCARDIOGRAPHY

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  POWERFUL DIAGNOSTIC TOOLDECREASE MORBIDITY INCREASE SURVIVAL
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  ANESTHETISED PATIENT’S PHYSIOLOGYIS DIFFERENT; WE KNOW IT BETTER! WE ARE CLOSELY LINKED WITH THE PERIOPERATIVE CARE
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  LUNGS AND RIBSDON’T INTERFERE ONLY ESOPHAGEAL WALL AND PERICARDIUM IN BETWEEN WONT DISRUPT SURGERY TRANS THORACIC IS DIFFICULT IN: OBESITY/EMPHYSEMA/ABNORMAL CHEST WALL
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  tissue insonated withsound above audible range, >20000 Hz Most use 2.5-7.5 Hz Transducer composed of piezoelectric crystals
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  Electrical signal appliedto the crystal  vibrate  sound  absorption/reflection/refraction/scattering  reflected ultrasound wave  crystal receive the reflected wave  convert it back to electrical signal
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  v = f x λ Ultrasound travels at 1540 m/sec Hence v constant As f increase, λ decrease v,f and λ known Time find out Hence depth find out
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  F more  absorption more  resolution more λ less  attenuation more  penetration less
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  Water, muscle, blood  less impedance  less attenuation Air , bone  high impedance  ultrasound traverse poorly
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  DOPPLER PRINCIPLE: “WHENA WAVE OF A GIVEN FREQUENCY,STRIKES A MOVING TARGET,IT WILL BE REFLECTED AND THE REFLECTED WAVE WILL SHOW A FREQUENCY SHIFT PROPORTIONAL TO THE VELOCITY OF THE TARGET WHICH IS PARALLEL TO THE PATH OF THE EMITTED WAVE”
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  If target ismoving away from the emitted wave, the frequency of the reflected wave will be lower If the target is moving towards the transducer, the frequency of the reflected wave will be higher
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  RBCs act asexcellent reflectors Measuring the RBC flow velocity in the heart is the application used here accurate when the transmitted beam and the velocity vector are parallel [ at least within 20º]
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  Most basic modeWaves transmitted as a single beam Only tissues which come in this narrow path are displayed Only a limited area is visualized Waves transmitted and received back in 0.001 sec
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  So 1000 frames/sec= REAL TIME High resolution : even subtle changes in motion/dimension are well picked Hence finer analysis best done with this mode
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  Amplitude of returningwaves are displayed as shades of brightness Blood filled chambers  no reflected waves  BLACK Valve tissue and myocardium  high reflected wave activity  grey/white ..\pdfnotes\Pocket Atlas of Echocardiography.pdf
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  Obtained by rapidrepetitive scanning along multiple beam lines within an area in the shape of a fan (sector), 60-90°wide Done by phased array technology Sector contains approx. 100 scan lines  time consuming Information updated 30-60 times
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  Desired view isobtained by 2D echo  Doppler beam superimposed Cursor is positioned as parallel as possible to the assumed direction of blood flow Quantify stenosis , regurgitation Demonstrate shunts ..\videos\video.flv
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  PULSED WAVE DOPPLERCONTINUOUS WAVE DOPPLER COLOR FLOW DOPPLER
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  a single crystalintermittently transmits and receives ultra sound signals  analyzed for frequency shifts Cursor placed on an updated 2D image and reflected wave from only that portion analyzed
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  We can contractor expand the interrogated area Problem : there is a velocity limit (.8-1 m/sec) for the wave, beyond which a phenomenon known as “aliasing” or “wraparound” occurs  ambiguous velocity and time information
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  Allows a flowdisturbance to be localized precisely or blood velocity from a small region to be measured correctly e.g. mitral inflow, tricuspid inflow
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  One transducer continuouslyemit signals Another one continuously receive reflected signals Very high velocities can be reliably detected Since no lag between emission and reception
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  i.e. extremely highsampling frequency  minimize aliasing problem : reflected signals returning from all points are analyzed.. Cant localize a signal precisely
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  Useful for: measuringhigh velocities e.g. intracardiac shunts , regurgitant jet, flow across stenotic valves like AS Velocities up to 600-800 cm/ sec can be measured
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  Uses pulsed wavetechnology to measure blood flow at multiple sites Real time blood flow is shown in colors While also showing 2D images in black and white
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  Velocities and directionsof blood flow are color encoded Velocity away  blue Velocity towards  red “BART” High turbulence  green As velocity increase intensity of color also increase
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  Aliasing occurs  color mosaic But as 2D image is there, direction of this aliased signal can be determined easily Assess valvular abnormalities , shunts, aortic dissection
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  Transducer fitted tothe distal, flexible end of a gastroscope Adult : above 20-25 Kg Pediatric : above 3.5- 4 Kg Adult @ 5 MHz Pediatric @7.5 MHz 2D—M-mode—PWD—CWD--COLOR
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  Two rotary knobsOne for anteflexion and retroflexion One for rightward and leftward flexion
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  Can rotate theangle plane without movement of the probe Good view of LA,MV.. ..\pdfnotes\iadt07i4p324.pdf
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  ADVANCED/WITHDRAWN RIGHT/LEFT ANTEFLEXED/RETROFLEXED-90°LATERAL FLEXION-70°
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  Single plane  0° Biplane  one transducer: 0° one transducer 90° Multiplane probes  0-180°
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  HISTORY: dysphagia/ hemetemesis/previous surgeries on GIT/ cervical spine disease Fasting for 4-6 hrs Remove dentures Airway/ oxygen delivery systems / bite block/ suction / intubation cart / IVA
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  TOPICAL : lignocaineSEDATION ANTIXYLAGOGUE
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  Orogastric tube Supine/ left lateral Operator stands as in for L’scopy ETT secured Probe in unlocked position  align with natural anatomy Lubricated Bite block on probe
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  Thumb of lefthand placed on patient’s tongue Left hand used to pull jaw upward Pass probe tip through bite guard , over tongue , maintaining it in midline ( transducer facing anteriorly) and to the left of ETT
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  Mild resistance felt@ pharyngo esophageal junction [ neonate: 10 cm from lip, adult : 20 cms] If doubt : done under laryngoscopy no hot water  1-2 hrs Not to eat  1-4 hrs
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  Inspected for defectsEnzymatic solution to remove secretions Gluteraldehyde for 20 mins Tap water dry for 20 mins
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  Apex of thesector scan is shown at the top of the echo screen which displays posterior parts of the heart ( part close to probe)
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  In the transverseimaging plane, left of image is towards patients right and right of the image is towards patients left
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  In the verticalimaging plane, left side of the image is inferior and point towards patient’s feet Right side of the image is anterior and points towards patients head ..\pdfnotes\iadt07i4p324.pdf
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  Once we centrea cardiac structure in one image plane,it will continue to remain there as the transducer is rotated from 0-180°,facilitating the 3D assessment of that particular structure
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  Markedly abnormal ventricularfunction Extensive MI Large air emboli Severe valvular dysfunction Large mass or thrombi Large effusion Major lesions of great vessels
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  20 views  comprehensive examination 8 out of 20 needed to meet these goals
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  Upper esophageal(20-30 cm)Mid esophageal(30-40 cm) Transgastric (40-45 cm) Deep transgastric (45-50 cm)
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  Aortic valve shortaxis—SAX Aortic valve long axis—LAX RV inflow-outflow Bicaval Ascending aorta—SAX Ascending aorta—LAX
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  4 chamber 2chamber Commissural Long axis
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  The probe isadvanced into the stomach and ante flexed ( to keep it apposed to the diaphragmatic surface of stomach)
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  Mid SAX Twochamber Basal SAX LAX RV inflow
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  TG mid SAXview is particularly used by the anesthetist in the assessment of LV function, Ejection Fraction and Volume status
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  Probe further advanced, slowly withdrawn with tip sharply anteflexed until it contacts the diaphragmatic surface of stomach wall LAX view shows all 4 chambers, aortic valve and LV outflow tract Estimates velocity via aortic valve and CO
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  Images aortic archand descending aorta
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  ..\videos\video.flv
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  Intraoperative assessment ofacute, life threatening hemodynamic disturbances Valve repair Congenital heart disease surgery Repair of HOCM
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  Intraoperative use- endocarditisPre operative use in unstable patients with suspected thoracic artery aneurysm / dissection Intraoperative assessment of aortic valve function during repair of aortic dissection Pericardial window procedures
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  Use in ICUpatients with unexplained hemodynamic disturbances/valve diseases/thrombotic complications
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  Confirm Localize Reassess LA clot LV function Associated abnormalities Congenital heart disease
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  Prosthetic valve: leakToo small? Moving normally? Deairing adequate? Adequacy of repair: Residual VSD? PA pressure Trouble in coming out of bypass?
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  Ventricular filling EjectionSystolic function Diastolic function Hypotension : low cardiac output Vs low SVR Guide for administration of fluid, inotropes and vasopressors
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  RWMA Differential diagnosisMyocarditis Myocardial stunning
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  PAC Vs TEETEE  Real time, directly visualizing, amount of information more PAC  CO,LVEDP rough estimates, indirect methods Cost?
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  LA clot beforeBMV? ASD device closure Aortic dissection : trans thoracic Vs TEE Thrombus Abnormal thorax
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  Preoperative assessment ofventricular function in high risk patients During placement of LV assist device Positioning of cannulae As a substitute of PAC Deployment of intravascular devices