Pulmonary artery catheterisation, Cardiac surgeries, Non cardiac surgeries, LVEDD and PA pressure relationship, Technique and complications of PA placement

1. PULMONARY ARTERY
CATHETERISATION,
TRANSOESOPHAGEAL
ECHOCARDIOGRAPHY &
2DECHOCARDIOGRAPHY
MODERATOR: DR.MANJUNATH
BY: DR. ARATI M. BADGANDI

2. PULMONARY ARTERYPULMONARY ARTERY
CATHETERISATIONCATHETERISATION
 Increased amount of diagnostic information obtained
in critically ill patients.
 With increasing number of patients with multisystem
organ dysfunction undergoing cardiac procedures,
PAC monitoring prevalent in cardiac surgical settings.
 Understanding of PA catheterization therefore
essential for anesthesiologists.
 1 of main reasons for measuring PCWP & PADP -
estimates of LAP, in turn an estimate of LVEDP.
 LVEDP - index of LVEDV - correlates well with LV
preload.

4. PAC PLACEMENT
 Right IJV technique of choice - direct path to RA.
 Placement through subclavian vein introducers
complicated by kinking of catheter when sternum is
retracted during cardiothoracic surgery.
 Considerations for insertion site of a PA catheter - same
as CVP catheters.
 Passage of PAC from vessel introducer to PA -
accomplished by monitoring pressure waveform from
distal port of catheter/under fluoroscopic guidance.
 Waveform monitoring - common technique for
perioperative heart catheterization.

5.  Std PAC 7-9Fr
circumference, 110 cm in
length marked at 10-cm
intervals, with 4 internal
lumens.
 Distal port at catheter tip
for PAP.
 2nd 30 cm more proximal
– for CVP.
 3rd leads to balloon near
tip.
 4th houses wires for
temperature thermistor,
end just proximal to
balloon.

6.  Requires aid of a skilled assistant.
 Before insertion, PAC passed through sterile
sheath - attaches to hub of introducer for
sterile manipulation of position.
 Assistant attaches distal & proximal port hubs
to pressure transducers, flushes to ensure
proper function & remove air from system.
 Balloon tested by filling it completely with
1.5 mL of air from volume-limited syringe -
ensure symmetry of expansion & patency.

7.  Air-filled balloon at tip of catheter serves to
“float” catheter forward with BF through RH
chambers into proper position in PA.
 Important to check assembly for proper function.
 When tip of PAC held near heart level, recorded
pressure should be 0 mm Hg, confirming
transducer was correctly adjusted.
 Catheter tip raised up straight to create a 30-
cm-tall vertical fluid column, which should
produce a pressure of 22 mm Hg (= 30 cm H2O)
on bedside monitor.

8.  Slightly larger skin nick (than for CVP)
-accommodate large-bore introducer sheath with
hemostasis valve at outer end & side-arm
extension for IV access.
 Tapered-tip, stiff dilator stylet placed inside
introducer sheath to facilitate passage into vein.
 Utmost care when introducing large dilator-
cannula assembly by advancing only to depth
required to enter vein, & threading introducer
into vein.
 Guidewire & dilator are removed, introducer
sheath is sutured in place.

9.  PAC is inserted through hemostasis valve of
introducer to depth of 20 cm or approximately
5 cm beyond tip of introducer sheath.
 Characteristic CVP waveform should be visible.
 Curvature of PAC should be oriented to point
just leftward of sagittal plane (11-o’clock
position as viewed from patient's head) to
facilitate passage through anteromedially
located TV.
 Balloon is inflated, catheter is advanced into
RA; through TV, RV and PV; into PA; finally into
wedge position.

10.  Crossing PV, dicrotic
notch appears in
pressure waveform -
sudden increase in
DBP.
 PCWP tracing - by
advancing catheter
3-5cm till change in
waveform & drop in
measured mean
pressure.

11.  Deflation of balloon - reappearance of PA waveform &
increase in mean pressure value.
 Characteristic waveforms from each location confirms
proper catheter passage & placement.

12.  After PAWP measured, balloon deflated & PAP
waveform should reappear.
 Wedge pressure obtained as needed by reinflating
balloon & allowing catheter to float distally until
PA occlusion occurs again.
 Tip of PAC advances to smaller pulmonary artery
each time balloon is inflated to measure wedge
pressure.
 In some, tip migrates distally without balloon
inflation – esp.in CPB - repeated cardiac
manipulations & temperature changes, altering
stiffness of PAC.

13.  Proper catheter position ensured by frequent
observation of pressure waveform.
 Using right IJV approach, RA entered at 25-35
cm, RV at 35-45 cm, PA at 45-55 cm, & PCWP at
50-60 cm in most patients.
 When other sites chosen for PAC placement,
additional distance is required. (extra 5-10 cm
from left IJV & left & right EJV, 15 cm from
femoral veins, 30-35 cm from antecubital veins.
 Balloon inflated only for short periods to measure
PCWP.

14.  If RV waveform not observed after inserting
catheter 40 cm, coiling in RA is likely.
 Similarly, if PA waveform not observed after
inserting catheter 50 cm, coiling in RV has
probably occurred.
 Balloon should be deflated, catheter withdrawn
to 20 cm, & PAC floating sequence repeated.
 If PAWP trace appears without balloon
inflation/partial inflation, balloon should be
deflated & PAC withdrawn several cm to reduce
risk of pulmonary vascular injury.

15.  Although external protective sleeve covering
PAC intended to maintain sterility during
minor adjustments, does not exclude
contamination.
 PACs should be manipulated only as necessary
to maintain proper location.
 Many clinicians believe that PAC should be
inserted before induction of anesthesia.

16.  Studies showed PAC insertion in awake patient
- no MI/deleterious hemodynamic changes
after preanesthetic medication & continuation
of preoperative cardiac medications.
 CXR postoperatively in all patients to check
position of PA catheter.
 Tip of PAC should be within 2 cm of the cardiac
silhouette on std AP CXR.
 Location also checked by TEE image of
catheter in RA, RV & PA.

17. ADDITIONAL GUIDELINES
 Air-filled balloon floats to nondependent regions
as it passes through heart into pulmonary
vasculature (patient head down aids flotation
past TV).
 Tilting patient to right side & placing head up -
encourage flotation out of RV.
 Deep inspiration during spontaneous ventilation
increases venous return & RV output transiently
- catheter flotation in patient with low CO.
 If initially difficult to place, may be positioned
easily when hemodynamic conditions change -
after induction of GA & positive-pressure.

18. INDICATIONS
 Considerable controversy regarding risk/benefit ratio of
PACs.
 Routine use indicated in high-risk patients (e.g., ASA 4
or 5) & high-risk procedures (e.g., where large fluid
changes/ hemodynamic disturbances expected).
 The setting is important - evidence that inadequate
training or experience increases risk for complications.

19. COMPLICATIONS
 Include almost all occurring with CVP placement

20. ARRHYTHMIAS
 Most common- transient arrhythmias, especially
PVCs.
 Positional maneuver 5-degree head-up & right lateral
tilt – statistically less malignant arrhythmias
(compared to Trendelenburg position) during
insertion.
 Complete Heart Block
 In preexisting left bundle-branch block LBBB.
 Due to electrical irritability from PAC tip causing
transient RBBB as it passes through RV outflow tract.
 Imperative to have an external pacemaker
immediately available/use a pacing PAC in such
patients.

21. ENDOBRONCHIAL HAEMMORHAGE
 Iatrogenic rupture of PA - common since advent
of PAC monitoring in ICU & operating room.
 Several risk factors: advanced age, pulmonary
HTN, MS, female sex, Coagulopathy, Distal
placement of catheter, Balloon hyperinflation.
 Balloon inflation in distal PAs - PA rupture due to
high pressures generated by it.
 Hypothermic CPB increases risk (distal migration
of catheter tip with movement of heart &
hardening of PA catheter) - common practice to
pull PA catheter back 3-5 cm when CPB
instituted.

22.  Hallmark of PAC-induced PA rupture –hemoptysis,
life-threatening exsanguination/hypoxemia.
 CXR reveals hemothorax/new infiltrate near tip of
distally positioned PAC.
 Diagnosis made by wedge angiogram - radiopaque
dye inj through wedged PAC extravasates into
parenchyma - identifies site of arterial disruption.
 Protection of uninvolved lung prime importance -
tilting patient toward affected side, placement of
DLT/lung-separation maneuvers to protect
contralateral lung.

23.  Ensuring adequate oxygenation & ventilation.
 PEEP applied to affected lung may help control
hemorrhage.
 Anticoagulation should be reversed unless
patient must remain on CPB & bronchoscopy
performed to localize & control bleeding.
 Bronchial blocker into involved bronchus to
tamponade bleeding.
 Many require surgical therapy - oversewing
involved PA/or resecting involved
segment/lobe/lung.

24.  Pulmonary Infarction
 Rare - Embolization of thrombus on PAC.
 Catheter Knotting and Entrapment
 Due to coiling within RV.
 Insertion of appropriately sized guidewire under
fluoroscopic guidance - unknotting.
 Or knot tightened & withdrawn percutaneously with
introducer (if no intracardiac structures entangled).
 If cardiac structures eg. papillary muscles, entangled in
knotted PAC - surgical intervention may be required.
 Valvular Damage
 Withdrawal of catheter with balloon inflated - injury to
TV/PV.
 Placement of PAC with balloon deflated - increases risk
of passing between chordae tendineae.

25. PHYSIOLOGIC CONSIDERATIONS,
PREDICTION OF LV FILLING PRESSURES
 PAC - measurement of variety of hemodynamic
variables, including CO, mixed venous oxygen
saturation, & most important, PADP PCWP.
 Used to estimate LV filling pressure &, in
combination with other clinical information -
helps guide administration of fluid & vasoactive
drugs.
 When PAC floats to wedge position, inflated
balloon isolates distal pressure-monitoring orifice
from upstream PAP.

26.  Continuous static column of blood connects
wedged PAC tip to junction of Pulmonary vein &
LA.
 Wedging thus extends catheter tip to measure
pressure at point at which blood flow resumes on
venous side of pulmonary circuit.
 As resistance in large pulmonary veins negligible,
PAWP - accurate, indirect measurement of
pulmonary venous pressure & LAP.
 PADP often used as alternative to PAWP -
estimate LVFP.

27.  Acceptable in normal circumstances (when pulmonary
venous resistance is low, pressure in PA at end of
diastole equilibrates with downstream pressure in
pulmonary veins & LA.)
 PADP – advantage - available for continuous
monitoring, while PAWP measured only intermittently.
 For PADP/PAWP to be valid estimate of LVFP, column
of blood connecting tip of wedged catheter & draining
pulmonary vein must be continuous & static.
 At microcirculatory level, channel consists of
pulmonary capillaries subject to external compression
by surrounding alveoli.

28.  West & colleagues - 3-zone model of
pulmonary vasculature based on gravitationally
determined relationships between relative
pressure in PAs, pulmonary veins, &
surrounding alveoli.
 In West zone 1, alveolar pressure > PA &
pulmonary veins, while in zone 2, it is
intermediate between these two pressures.
 PAC positioned in zone 1 & 2 - highly
susceptible to alveolar pressure, &
measurements reflect alveolar or airway
pressure rather than LVFP.

29.  Tip of PAC must lie in zone 3 for PAWP
measurements to be accurate.
 Supine position favors zone 3 condition -
confirmed by radiographic studies.
 In lateral/semi-upright position, zone 2 may
expand significantly.
 Zones 1 & 2 more extensive when LAP is low,
when PAC tip is located vertically above LA, or
when alveolar pressure is high.

30.  Clues to incorrectly positioned PAC:
 1.absence of normal PAWP a & v waves,
 2.marked respiratory variation in PAWP,
 3.PADP > PAWP measurement without excessively
tall a/v waves on trace

31. NORMAL PA WEDGE PRESSURE WAVEFORMS
 In SVC/RA, CVP waveform observed, with a, c, v
waves & low mean pressure.
 Here PAC balloon inflated & catheter advanced
until crosses TV to record RVP - rapid systolic
upstroke, wide pulse pressure, low diastolic
pressure.
 Next enters RV outflow tract & floats past PV into
main PA.
 PVCs common during this period - balloon-tipped
catheter strikes RV infundibular wall.

32.  Entry into PA - step-up in diastolic pressure,
change in waveform morphology.
 May be difficult to distinguish RVP from PAP, if
only numeric values examined.
 Observation of waveform & diastolic contours
allows differentiation.
 During diastole, PAP falls due to interruption of
flow during PV closure & pressure in RV
increases due to of filling from RA.
 PAP upstroke slightly precedes radial artery
pressure upstroke due to longer duration of LV
isovolumic contraction, & time for propagation of
pressure wave to distal monitoring site.

33.  PCWP - indirect measurement of pulmonary venous
pressure & LAP - should resemble these
waveforms, with characteristic a, v waves, x & y
descents
 Due to interposition of pulmonary vascular bed
between PAC tip & LA, PCWP delayed
representation of LAP.
 160 msec for LAP pulse to traverse pulmonary
veins, capillaries, arterioles & arteries.

34.  Due to delay, PCWP a wave follows ECG R wave
in early ventricular systole (though a wave end-
diastolic event)
 To recognize prominent a/v waves in PCWP, not
necessary to inflate PAC balloon.
 Tall LA a/v waves distorts normal PAP waveform,
with a wave inscribed at onset of systolic
upstroke & v wave distorting dicrotic notch.
 Once waves identified by wedging PAC &
comparing PAP & PCWP traces - follow PCWP a &
v waves in unwedged PAP rather than repeatedly
inflating balloon.

35. SUMMARY
 PAWP measured with a balloon-tipped PAC
-delayed, damped estimate of LAP by
measuring pressure near junction of
pulmonary veins & LA.
 Mean wedge pressure should be < mean PAP;
otherwise, blood would not flow in an
antegrade direction.
 PAWP waveform should display small but
visible a & v waves if pressure trace is
displayed with sufficient gain & resolution on
monitor.

36. ABNORMAL PCWP & PAWP WAVEFORMS
 As PAC is longer & passes through cardiac chambers
prone to distortions from clot/air bubbles, & motion-
related artifacts.
 Artifactual spikes - unique morphology & timing.
 At onset of systole, TV closure accompanied by RV
contraction & ejection - excessive catheter motion most
common artifact.
 Simultaneous with CVP c wave, may produce artificially
low pressure/pressure peak.
 Repositioning solves problem.

37.  When balloon overinflated & occludes lumen orifice,
termed overwedging – distal PAC migration &
eccentric balloon inflation, forcing tip against vessel
wall.
 Catheter records gradually rising pressure caused by
continuous flush system & builds up pressure against
obstructed distal opening.
 If PAC migrated to more distal position, possible for
overwedging without balloon inflation.

38.  Overwedged pressure - devoid of pulsatility,
higher than expected, & rises continuously to
flush pressure. (Such pattern prompt corrective
action.)
 When wedge tracing appears during partial
balloon inflation - suggests PAC inappropriately
located in a smaller, distal branch of PA.
 PAC withdrawn before overwedging results in
vascular injury/pulmonary infarction.
 Pathophysiologic conditions involving LH
chambers/valves produce characteristic changes
in PA & wedge pressure waveforms.

40.  Tall v wave of MR begins in early systole.
 Fusion of c & v waves, obliteration of systolic x
descent as isovolumic phase of LV systole
eliminated (retrograde ejection of blood into LA).
 As prominent v wave of MR generated during
ventricular systole, mean wedge pressure
overestimates LV filling pressure.

41.  Consequently, in severe MR, LVEDP best
estimated by measuring wedge pressure before
onset of regurgitant v wave).
 Larger the v wave, more the regurgitant v wave
distorts PA waveform by giving bifid appearance
& obscuring normal end-systolic dicrotic notch.
 Giant v waves in VSDs not due to retrograde
flow, rather excessive antegrade systolic flow
into LA due to intracardiac shunt.
 Compared to MR (distorts systolic part of
waveform), MS alters diastolic part.

42.  Holodiastolic pressure gradient across MV -
increased mean wedge pressure, slurred early
diastolic y descent, & tall end-diastolic a wave.
 Similar abnormalities in LA myxoma/obstruction
to mitral flow.
 Increased LV stiffness (e.g., LV infarction,
pericardial constriction, AS, & systemic HTN) -
changes in wedge pressure as seen in MS.
 Here, mean wedge pressure increased & trace
displays prominent a wave, but y descent
remains steep (as no obstruction to flow across
MV).
 Advanced MS often coexisting AF, a wave not
present in many.

44.  MI detected with PAC in several ways.
 Ischemia impairs LV relaxation - diastolic
dysfunction, characteristic of demand ischemia.
 Impaired ventricular relaxation - less compliant LV -
increased LVEDP.
 Increased LA & wedge pressure, & changes in
morphology of waveforms, with phasic a & v wave
more prominent as diastolic filling pressure
increases.

45.  In LV ischemia, tall wedge pressure a wave
produced by end-diastolic atrial contraction
into stiff, incompletely relaxed LV.
 Systolic dysfunction - hallmark of supply
ischemia, caused by sudden
reduction/cessation of coronary BF to region of
myocardium.
 With severe systolic dysfunction, changes in
global LV contractile performance may be
detected by hemodynamic monitoring.

46.  As EF falls significantly, LVEDV & P rise, &
systemic arterial hypotension & elevated
pulmonary diastolic & wedge pressure develop.
 When LV distorted/ region of ischemic
myocardium underlies papillary muscle - acute
MR, termed “papillary muscle
ischemia”/“functionalMR.”
 Most important problem in PAC monitoring -
discerning correct pressure measurement in
patients receiving PPV/labored spontaneous
respiration/causes of greatly increased
intrathoracic pressure.

47.  During PPV, inspiration increases PA & wedge
pressure.
 By measuring pressures at end-expiration,
confounding effect of inspiratory increase in
intrathoracic pressure minimized.
 Forceful inspiration during spontaneous
ventilation - opposite effect, but measurement of
pressures at end-expiration eliminates
confounding factor.

50.  PACs are multipurpose, provide wide range of
supplementary features for therapeutic & diagnostic
applications.
 Some catheters have added lumen often used as venous
infusion line that opens either 20 or 30 cm from the
catheter tip.
 Others - specific modifications for monitoring
continuous CO, RH function, or mixed venous oximetry
– expanding types of physiologic information available
to those caring for critically ill patients.

51.  Specialized PACs allow temporary endocardial
pacing/intracardiac ECG recording & may have
combinations of electrodes permanently implanted
along its length to allow bipolar ventricular, atrial, or
AV pacing.
 Others have special lumen that opens in RV, through
which thin bipolar wire may be introduced for
endocardial ventricular pacing/have separate atrial &
ventricular lumens for passage of two pacing wires
for bichamber sequential pacing.

53.  Properties of Ultrasound
 Imaging Techniques
 Equipment
 Complications
 Technique of Probe Passage
 Anatomy & Views
 Clinical Applications
 Intraoperative Indications

54.  In early 1980s, when TEE first used in OR - assessment
of global & regional LV function.
 Numerous technical advances:
 biplane & multiplane probes;
 multifrequency probes;
 enhanced scanning resolution;
 color flow, pulsed wave & continuous wave Doppler;
 automatic edge detection;
 Doppler tissue imaging;
 3D reconstruction;
 Digital image processing.

56.  In echo, heart & great vessels insonated with
ultrasound (above human audible range).
 Ultrasound sent into thoracic cavity, partially
reflected by cardiac structures, from which - distance,
velocity & density of objects within chest derived.
 Wavelength, Frequency, and Velocity
 Ultrasound beam – continuous/intermittent train of
sound waves emitted by transducer/wave generator,
composed of density/ pressure waves & can exist in
any medium (exception of vacuum).

57.  Waves characterized by their wavelength, frequency &
velocity.
 Wavelength - distance between two nearest points of
equal pressure/density in an ultrasound beam.
 Velocity - speed at which the waves propagate through
a medium.
 As waves travel past fixed point in ultrasound beam,
pressure cycles regularly between high & low value.
Number of cycles/s (Hertz) - frequency.
 Ultrasound - frequencies above 20,000 Hz (upper limit
of human audible range).

58.  Propagation velocity = frequency X length
 Piezoelectric crystals convert energy between
ultrasound & electrical signals.
 When presented with a high-frequency electrical signal,
these crystals produce ultrasound energy, directed
toward areas to be imaged.
 Short ultrasound signal is emitted from the piezoelectric
crystal.
 After ultrasound wave formation, crystal “listens” for
returning echoes for given period of time & pauses
before repeating cycle.

59.  This cycle length - pulse repetition frequency (PRF) - long
enough to provide time for signal to travel to & return
from a given object.
 PRFs vary from 1-10 kHz, resulting in 0.1-1.0ms
intervals between pulses.
 When reflected waves return to piezoelectric crystals,
converted into electrical signals - appropriately
processed & displayed.
 Electronic circuits measure time delay between emitted
& received echo (speed of ultrasound through tissue
constant, time delay converted into precise distance
between transducer & tissue).

61.  M Mode
 Density & position of all tissues in path of a narrow
ultrasound beam (i.e., along a single line) displayed as
scroll on video screen.
 Scrolling produces updated, continuously changing
time plot of studied tissue section, several seconds in
duration.
 Timed motion display (normal cardiac tissue always in
motion) - M mode.
 Limited part of heart observed at one time & image
requires considerable interpretation, not currently used
as primary imaging technique.
 Useful for precise timing of events within cardiac cycle
& often used in combination with color flow Doppler
imaging for & timing of abnormal flows.

62.  2D Mode
 By rapid, repetitive scanning along many different radii
within area in shape of a fan (sector), echo generates 2D
image of section of the heart.
 Image is an anatomic section & can be easily
interpreted.
 Info on structures & motion in plane of 2D scan
updated 30-60 times/second.
 Repetitive update produces “live” (real-time) image of
heart.
 Scanning 2D echo devices image heart by using
mechanically-steered transducer/electronically-steered
ultrasound beam (phased-array transducer).

63.  Doppler Techniques
 Most modern scanners combine Doppler capabilities &
2D imaging capabilities.
 After desired view of heart obtained by 2D echo,
Doppler beam (represented by a cursor) superimposed.
 Operator positions cursor as parallel as possible to
assumed direction of BF & empirically adjusts direction
of beam to optimize audio & visual representations of
reflected Doppler signal.
 4 ways to measure blood velocities:
 pulsed wave high repetition frequency
 continuous wave color flow

65.  Color Flow Mapping
 Doppler scanners - real-time BF within heart as colors
while showing 2D images in black & white.
 In addition to showing location, direction, & velocity of
cardiac BF, images produced allow estimation of flow
acceleration & differentiation of laminar & turbulent BF.
 Location in heart where scanner has detected flow toward
transducer (top of image sector) is assigned color red.
 Color assignment arbitrary, determined by equipment
manufacturer & user's color mapping. Flow away from
direction of top assigned color blue.

66.  In most common color flow coding scheme, faster the
velocity (up to a limit), more intense is color.
 Flow velocities that change by more than a preset value
within a brief time interval (flow variance) have color
green added to red/blue.
 Rapidly accelerating laminar flow (change in flow
speed) & turbulent flow (change in flow direction)
satisfy criteria for rapid changes in velocity.
 Brightness of red/blue colors at any location & time is
usually proportional to corresponding flow velocity
while hue is proportional to temporal rate of change of
velocity.

67.  Contrast Echocardiography
 RBCs scatter ultrasound waves weakly - black
appearance on ultrasound examination.
 Contrast echo - by injecting nontoxic solutions with
microbubbles (shell surrounding gas).
 Microbubbles - additional gas-liquid interfaces -
substantially increase strength of returning signal, used
to define endocardial borders, optimize Doppler
envelope signals & estimate myocardial perfusion.
 Contrast echo used to image
 intracardiac shunts,
 valvular incompetence,
 pericardial effusions.

68.  Initial contrast agents -
agitated free air in saline
or blood/saline solution,
(large & unstable, unable
to cross pulmonary
circulation;effective only
for RH contrast).
 Due to thin shell, gas
quickly leaked into blood
with resultant dissolution.
 Agents with longer
persistence subsequently
developed.

69.  All TEE probes - multifrequency transducer mounted
on tip of gastroscope housing.
 Majority echo examination performed using ultrasound
between 3.5-7 MHz.
 Tip directed by adjustment of knobs placed at proximal
handle.
 Most adult probes - two knobs; 1 allows anterior &
posterior movement, & other permits side-to-side
motion.
 Multiplane probes also include control to rotate
echocardiographic array from 0-180 degrees.

71.  With ability to advance & withdraw probe & to rotate
it, many echo windows are possible.
 Another feature common to most probes is
temperature sensor to warn of possible heat injury
from transducer to esophagus.
 Adult probes multiplane (variable orientation of
scanning plane) & pediatric probes
multiplane/biplane (transverse & longitudinal
orientation, parallel to shaft).
 Adult probes usually have length of 100 cm, 9-12 mm
in diameter.
 One limitation of TEE - structures very close to probe
are seen only in very narrow sector.

72.  Tips vary in shape & size (1-2 mm wider than shaft).
Size of probes requires patient to weigh at least 20
kg.
 Adult probes contain 32-64 elements/scanning
orientation - image quality directly related to number
of elements used.
 Pediatric probes mounted on narrower, shorter shaft
with smaller transducers, used in patients as small as
1 kg.
 Feature often available - ability to alter scanning
frequency (lower frequency, such as 3.5 MHz, has
greater penetration & more suited for transgastric
view) - increases Doppler velocity limits.
 Conversely, higher frequencies yield better resolution
for detailed imaging.

74.  Absolute contraindications to TEE in intubated
patients:
 Oesophageal stricture
 Diverticula
 Tumor
 Recent suture lines
 Known esophageal interruption.
 Relative contraindications:
 Symptomatic hiatal hernia
 Oesophagitis
 Coagulopathy
 Oesophageal varices
 Unexplained upper GI bleeding

75.  Usual technique - place well-lubricated probe in
posterior portion of oropharynx with transducer
element pointing inferiorly & anteriorly.
 Stabilized by looping controls & proximal portion of
probe over operator's neck & shoulder.
 Left hand elevates mandible by inserting thumb behind
teeth, grasping submandibular region with fingers &
gently lifting.
 Probe advanced against slight even resistance, till loss
of resistance detected as tip of passes inferior
constrictor muscle (occurs 10 cm past lips in neonates &
20 cm past lips in adults).
 Further manipulation under echo guidance.

76.  Difficult TEE probe insertion may be caused:
 probe tip abutting the pyriform sinuses, vallecula,
posterior tongue,
 esophageal diverticulum.
 Overinflation of ETT tube cuff could obstruct passage.
 Maneuvers that aid passage:
 changing the neck position,
 realigning TEE probe,
 applying additional jaw thrust.
 may be passed with assistance of DL.

79.  LV carefully examined for global & regional function
using multiple transducer planes, depths, rotational &
angular orientations.
 Analysis of segmental function based on qualitative
visual assessment - following grading system of LV
wall thickness & motion (endocardial border excursion)
during systole:
 1 = normal (>30% thickening);
 2 = mild hypokinesis (10% to 30% thickening);
 3 = severe hypokinesis (<10% thickening);
 4 = akinesis (no thickening);
 5 = dyskinesis (paradoxical motion).

80.  CVS function - global indices of muscle
contraction /regional indices described by segmental
wall motion, is assessed by analyzing moving
echocardiographic images.
 Assessment of global & regional ventricular function
cornerstone for evaluating patients with ischemic
heart disease (IHD).
 Dynamic assessment of ventricular function with
echocardiography is based on derived indices of
muscle contraction and relaxation.

81.  Echo indices of LV function that incorporate endocardial
border outlines and Doppler techniques can be used to
estimate CO, stroke volume (SV), ejection fraction (EF),
and parameters of ventricular relaxation and filling.
 Global LV performance is directly related to preload,
contractility, and afterload.
 CO reflects systolic function and is an important factor in
oxygen delivery.
 Alteration in LV diastolic function may result from
systolic dysfunction or, in as many as 40% of patients,
may be the primary and main etiology of cardiac failure

82.  Visual Estimation of Function
 Estimations of global ventricular function performed
in short-axis view of LV (additional info can be
gained by assessing long-axis views of LV).
 Observer examines end-diastolic image & compares it
with end-systolic frame to determine degree of
ejection. Rate of ejection is also estimated.
 RWMAs identified on visual inspection of
echocardiographic images by anesthesiologists.

83.  Preload/Diastolic Function
 Estimated by measuring LH filling pressures (PCWP,
LAP, LVEDP), in echo determined by measuring LVED
dimensions.
 ED dimensions better index of preload than PCWP.
 TEE for practical reasons, limited to single short-axis
view at level of papillary muscles.
 2 main signs of decreased preload:
 (1) decrease in EDA (<5.5 cm2
/m2
) invariably reflects
hypovolemia;
 (2) obliteration of end-systolic area (ESA) accompanies
decrease in EDA in severe hypovolemia.

84.  Most obvious limitation of TEE - ischemia cannot be
detected during critical periods - induction/
laryngoscopy/ intubation/ emergence/extubation.
 In addition, the adequacy of RWMA analysis may be
influenced by artifact.

85.  Category I
 Heart valve repair
 Congenital heart surgery
 Hypertrophic obstructive cardiomyopathy
 Endocarditis
 Acute aortic dissection
 Acute, unstable aortic aneurysm
 Aortic valve function in the setting of aortic dissection
 Traumatic thoracic aortic disruption
 Pericardial tamponade

86.  Category II
 Myocardial ischemia and coronary artery disease
 Increased risk of hemodynamic disturbances
 Heart valve replacement
 Aneurysms of the heart
 Intracardiac masses
 Intracardiac foreign bodies
 Air emboli
 Intracardiac thrombi
 Massive pulmonary emboli
 Traumatic cardiac injury
 Chronic aortic dissection
 Chronic aortic aneurysm

87.  Detection of aortic atheromatous disease as a source of
emboli
 Evaluating the effectiveness of pericardiectomies
 Heart-lung transplantation
 Mechanical circulatory support
 Category III
 Other cardiomyopathy
 Emboli during orthopedic procedures
 Uncomplicated pericarditis
 Pleuropulmonary disease
 Placement of intra-aortic balloon pump, pulmonary
artery catheter
 Monitoring the administration of cardioplegia

88.  In unsecured airway, TTE is easier to perform than TEE
- entirely noninvasive.
 TTE uses frequencies lower (1 to 3 MHz) than TEE does
to penetrate greater distances inherent in transthoracic
technique - previously discussed modalities can be
performed with TTE.
 Probes are different from linear probes used to identify
superficial vascular structures & nerve bundles.
 TTE uses three standard “windows” (soft tissue points
that avoid interposition of bone between the transducer
and heart): parasternal (PS), apical (AP), and subcostal
(SC).

89.  Examination begins with patient turned halfway onto
left side with left arm elevated alongside head.
 Optimal imaging requires ultrasound gel between
probe & chest wall.
 Parasternal long-axis (PS LAX) cross section is acquired
first by placing the probe on the left side of the sternum
at the level of 4th
ICS & directing ultrasound beam
toward patient's right shoulder – shows ME LAX in
TEE.
 Parasternal short-axis (PS SAX) - rotating transducer 90
degrees clockwise & angling inferiorly toward left hip
until RV appears - crescent-shaped structure at top of
display & LV in SAX is viewed at bottom – same view
as TG SAX in TEE.

90.  Apical window - placing transducer in 4th
/5th
ICS lateral to
nipple line with transducer marker pointing toward the
floor.
 Appropriate adjustment - apical four-chamber (AP-4C) -
apex of heart on top of display & right & LA on bottom –
same as ME 4C in TEE.
 Apical two-chamber (AP-2C) - rotating transducer 60
degrees counterclockwise – same as ME 2C in TEE - reveals
segmental function of anterior & inferior walls of LV.
 Apical long-axis (AP LAX) - rotating transducer
counterclockwise another 60 degrees until LV outflow tract &
AV seen in bottom of display – same as ME LAX in TEE.
 Last 2 sections - from subcostal window with patient supine
– transducer flat under right costal ridge next to xiphoid,
pointed to left shoulder with marker pointing leftward.

91.  Subcostal 4-chamber (SC-4C) – with upper 1/3 of
display occupied by liver & heart below - RV free wall
contractility & hemodynamically significant pericardial
effusion best viewed.
 SC IVC cross section - rotating transducer 90 degrees
counterclockwise – IVC seen on left side of display as
rectangular echolucent structure inside liver connecting
to RA.
 Allows assessment of RH filling pressure by evaluating
size & collapsibility of IVC in spontaneously breathing
patients.
 When TEE impracticable & CVS status must be
evaluated reliably, TTE can provide same info as TEE.