Common BedSide Procedures in ICU

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Common Bed-Side Procedures in ICU

• Wang, Tzong-Luen, MD, PhD, FESC, FACC
• Shin-Kong Wu Ho-Su Memorial Hospital

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Contents

• www.emedicine.com
• www.medscape.com
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• Swan-Ganz Catheter
• Intra-Aortic Balloon Counter-pulsation
• Transvenous Pacemaker
• Airway Management / Capnography

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Swan-Ganz Catheter
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Intra-Aortic Balloon Counter-Pulsation (IABP)
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Blood Pressure during IABP

• balloon inflation, termed "diastolic augmented
  pressure"
• balloon deflation during end-diastole producing a
  low pressure point termed "balloon assisted
  aortic end-diastolic pressure" (BAEDP)
• patient's aortic end-diastolic pressure (without
  the IAB impact), called "unassisted aortic
  end-diastolic pressure," (UAEDP)
• assisted systole, or the systolic pressure that
  is generated after a balloon inflation-deflation
  cycle and
• systole without a preceding IAB-pumped beat,
  termed "unassisted systole."

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Indication (1)

• pump failure or cardiogenic shock as indicated by
  hemodynamic instability (BP lt 90 mm Hg, cardiac
  index lt 2, pulmonary capillary wedge pressure gt
  18 mm Hg, ST elevation) refractory to volume
  optimization and inotropic support
• cardiac surgical patients at risk for hemodynamic
  decompensation
• severe left-main disease
• ischemic changes during hypotensive episodes
  (anesthesia)

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Indication (2)

• hemodynamic or ECG instability in catheterization
  laboratory (ie, "cath lab")
• ventricular arrhythmia unresponsive to
  conventional treatment
• cardiac failure due to CAD complications
  resistant to inotropes and diuresis
• LV aneurysm
• acute mitral insufficiency

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Indication (3)

• mechanical complications of AMI (eg, acute mitral
  regurgitation)
• postinfarction ventricular-septal rupture
• hemodynamic/ECG instability during early surgical
  phase pre-cardiopulmonary bypass
• failure to wean from cardiopulmonary bypass
• bridge to cardiac transplantation
• stunned myocardium

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Contraindication (1)

• Severe aortic valvular insufficiency
• Aortic dissection
• Severe peripheral vascular disease
• Irreversible Brain Damage

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Effects of IABP
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Myocardial Oxygen Consumption
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Factors decreasing Augmentation

• Positioning
• The proximal tip of the IAB should be
  positioned just below the bifurcation of the left
  subclavian artery (Fig.1). If the IAB is
  positioned too low, diastolic augmentation will
  be reduced as inflation momemtum is decreased.
• Volume
• Diastolic augmentation is maximized when
  stroke volume is equal to balloon volume. If
  stroke volume is less than 25 ml, little
  diastolic augmentation can be expected. On the
  contrary, a stroke volume greater than 50 ml is
  beyond the displacement capabilities of the
  inflating IAB. Augmentation will, therefore, also
  be decreased.

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Factors decreasing Augmentation

• Systemic Vascular Resistance
• As systemic vascular resistance increases,
  diastolic augmentation may decrease because of
  the associated decrease in compliance.
  Conversely, an extremely low systemic vascular
  resistance also will produce poor augmentation.
• Timing
• Early inflation or late deflation can
  decrease the amount of time that helium gas
  inflates the IAB. Thus, a shortened deflation
  imposed by erroneous balloon timing will
  understandably decrease the magnitude of
  inflation.

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Complication
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Transcutaneous Pacemaker
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Application

• Electrodes/pads and monitor leads, if necessary,
  are placed on the patient.
• About 2-3 cm of space should be left if separate
  defibrillation pads are required, and the second
  pad should be placed posteriorly, just below the
  left scapula.
• The desired heart rate is chosen and the current
  is set to zero milliamperes (mA).
• The TCP is then turned on and the current is
  increased as tolerated until capture is achieved.

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Pulse Duration

• Pulse duration is the time of impulse
  stimulation.
• Early TCPs used short (1-2 msec) duration
  impulses. Such impulses resembled the action
  potential and preferentially stimulated skeletal
  muscle.
• In contrast, cardiac muscle action potentials are
  much longer, requiring 20-40 msec to reach
  maximum.

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Pulse Duration

• Zoll found that increasing the duration from 1 to
  4 msec resulted in a 3-fold reduction in
  threshold (the current required for stimulation).
  
• Increasing the current from 4 to 40 msec further
  halves the threshold.
• Longer durations produced no further advantage.
  Current TCPs deliver 40 (Zoll) or 20 (all others)
  msec pulses.

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Current

• External pacing in dogs requires 30-100 times
  greater than internal transvenous pacing.
• Human studies have shown that the average current
  necessary for external pacing is about 65-100 mA
  in unstable bradycardias and about 50-70 mA in
  hemodynamically stable patients and volunteers.
• At this current, more than 90 of patients
  tolerated pacing for 15 or more minutes.
• Higher amounts are needed to stimulate the atria.

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Current

• Using a longer pulse duration and larger
  electrodes permits patients to tolerate higher
  applied current.
• One hundred milliamperes of current applied over
  an average (50-ohm resistance) chest for 20 msec
  will deliver 0.1 Joules. This is well below the
  1-2 Joules required to cause an uncomfortable
  tingling sensation in the skin.
• The force of skeletal muscle contraction, not the
  electric current, determines TCP discomfort.
  Current TCPs are capable of delivering up to
  140-200 mA tolerably.

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Electrode

• Pain is a function of the current delivered per
  unit of area. Pain sensation is minimized by
  electrodes with a surface area of at least 5 cm2.
  
• The amount of pain for a current of a given
  strength reaches a plateau once the electrode
  surface area exceeds 10 cm2.
• Most commercially available electrodes are 80-100
  cm2. TCPs generally perform best with their own
  pads, but different combinations may be helpful.

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Monitor

• Determination of electrical capture and pulse
  generation can be difficult when skeletal muscle
  is stimulated. In the 1950s, Zoll developed a TCP
  with an ECG monitor that allowed for
  identification of electrical capture. Blanking
  protection, currently only available in Zoll
  models, changes high output pacing stimulus to a
  smaller ECG waveform, preventing overdriving of
  the ECG.
• If blanking protection is not present, a second
  monitor or clinical palpation of the pulse is
  needed to determine capture.

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Mode

• In the fixed rate (asynchronous) mode, the TCP
  delivers an electrical stimulus at preset
  intervals, independent of intrinsic cardiac
  activity. In theory, this could induce
  arrhythmias if stimulation occurs during the
  vulnerable period. Early models only had
  fixed-rate capabilities.
• Most current models have fixed rate and
  synchronous pacing. Synchronous pacing is a
  demand mode in which the pacer fires only when no
  complex is sensed for a predetermined amount of
  time. Pacing generally should be started in the
  synchronous mode.

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Special Considerations

• Minimizing discomfort
• Skeletal muscle contraction can be uncomfortable
  and is often the limiting factor in TCP use.
  Placing electrodes over areas of least skeletal
  muscle can minimize discomfort. Placement is
  generally best in the midline chest and just
  below the left scapula. The physician also should
  use the lowest effective current. Sedation should
  be considered if these measures are inadequate.

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Special Considerations

• CPR
• CPR can be performed with the TEP pads in place.
  The low Joules delivered and the insulation of
  the flexible TEP pads result in no electrical
  hazard to the person performing CPR. However,
  turning the unit off during CPR is advisable.
• In TCPs without an intrinsic defibrillator,
  separate leads need to be applied. The external
  pacemaker should be turned off or to monitoring
  mode when defibrillating or cardioverting a
  patient. Defibrillator paddles should be placed
  at least 2-3 cm away from TEP stimulation pads to
  prevent arcing of current. Pacing pads should be
  placed in the anterior/posterior position.

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Transvenous Pacemaker
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Pacemaker code used to describe various pacing
modes
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Indications
Symptomatic Bradycardia

• Sick sinus syndrome
• Symptomatic sinus bradycardia
• Tachy-brady syndrome
• Atrial fibrillation with a slow ventricular
  response
• Complete atrioventricular block (third-degree
  block)
• Chronotropic incompetence (inability to increase
  the heart rate to match a level of exercise)
• Long QT syndrome Relative indications include the
  following
• Cardiomyopathy (hypertrophic or dilated)
• Severe refractory neurocardiogenic syncope
• Paroxysmal atrial fibrillation

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Procedure

• ???? --
• a. CVP ?????? -- ?? alcohol sponge, better-iodine
  sponge, OP site, 0.9 NS, 10 ? 20 cc ??, ??
• b. Electrode catheter set ?? -- ??????,
  dilator,introducer, puncture needle, guiding wire
• c. Pacemaker generator, ?? 9 V ????
• d. ?????
• e. EKG monitor, ??? ( defibrillator )

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Procedure

• ???? -- ?????????
• 1. ??
• 2. ? EKG monitor ????? spike, ?? leads ??????,
  ??????, ???????
• 3. ? Chest PA ? check catheter tip ????
• 4. ????, ????? pacemaker generator ?? 10 ????,
  ?????

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Procedure

• ?? (rate) ???
• 1. ???? -- ????????????
• 2. ???? -- ????????????
• 3. ???? -- ????? pacing ????????? ( SVT
  ),???????? overdrive ?????? pacing

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Procedure

• ???? (output current)
• 1. ??? 1 ??? ( 1mA ) ??, ? 0.5 mA ???, ???????(
  threshold potential ) ?????????? ( capture ),
  ????????????? 2 ? 5 ??
• 2. ????? electrode ???, ?????????? 20 mA,
  ????????????????

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Selection

• ??????
• 1. ?????? -- ?? synchronized demand, ????
• 2. ????????? ( AV sequential pacemaker )
  --?????????????, double-chamber
  pacing,double-chamber sensing and double-mode
  response (atrial inhibited, ventricular paced ) ?
  DDD ??,?????????????
• 3. ??????? ( transesophageal cardiac pacing )--
  ????????, ???????? pacing,?? SVT ? overdrive
  suppression ???????reentrant dysrhythmia,?? AF,Af
  ????????????????
• 4. ????? intracardiac pacing catheter ?????????

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Complications

• 1. ?????, ?? ( tamponade ), ?????????
• 2. ??
• 3. ???????????, ????, ???????( desensitization ),
  generator ??????????????
• 4. pacing ?????????????????????????????
• 5. ????????? ( hiccup )?
• 6. ? ICU ?????????????????????? capture ???

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Comlications

• Pacing Failure
• Failure to Output
• Failure to Capture
• Pseudomalfunction
• Sensing Failure
• Oversensing
• Undersensing
• Operative Failure

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Failure to Output

• Failure to output occurs when no pacing spike is
  present despite an indication to pace.
• This may be due to battery failure, lead
  fracture, a break in lead insulation, oversensing
  (inhibiting pacer output), poor lead connection
  at the takeoff from the pacer, and "cross-talk"
  (ie, a phenomenon seen when atrial output is
  sensed by a ventricular lead in a dual-chamber
  pacer).

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Failure to Capture

• Failure to capture occurs when a pacing spike is
  not followed by either an atrial or a ventricular
  complex.
• This may be due to lead fracture, lead
  dislodgement, a break in lead insulation, an
  elevated pacing threshold, myocardial infarction
  at the lead tip, certain drugs (eg, flecainide),
  metabolic abnormalities (eg, hyperkalemia,
  acidosis, alkalosis), cardiac perforation, poor
  lead connection at the takeoff from the
  generator, and improper amplitude or pulse width
  settings.

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Failure to Capture

• Management of pacer capture complications is the
  same as for output complications, with extra
  consideration given to treating metabolic
  abnormalities and potential myocardial
  infarction.

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Oversensing

• Oversensing occurs when a pacer incorrectly
  senses electrical activity and is inhibited from
  correctly pacing.
• This may be due to muscular activity,
  particularly oversensing of the diaphragm or
  pectoralis muscles, electromagnetic interference,
  or lead insulation breakage.

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Undersensing

• Undersensing occurs when a pacer incorrectly
  misses intrinsic depolarization and paces despite
  intrinsic activity.
• This may be due to poor lead positioning, lead
  dislodgment, magnet application, low battery
  states, or myocardial infarction. Management is
  similar to that for other types of failures.

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Undersensing

• A final category of pacer failures is termed
  operative.
• This includes malfunction due to mechanical
  factors, such as pneumothorax, pericarditis,
  infection, skin erosion, hematoma, lead
  dislodgment, and venous thrombosis. Treatment
  depends on the etiology.

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Undersensing

• Pneumothoraces may require chest thoracostomy. If
  infection is present, Staphylococcus aureus is
  common in postoperative patients while
  Staphylococcus epidermidis is common following
  the postoperative period.
• Erosion of the pacer through the skin, while
  rare, requires pacer replacement and systemic
  antibiotics.
• Hematomas may require drainage.
• Lead dislodgment usually occurs within 2 days
  following implantation of a permanent pacer and
  may be seen on chest radiography. If the lead is
  floating freely in the ventricle, malignant
  arrhythmias may develop.
• Thrombosis is rare and usually presents as
  unilateral arm edema. Treatment includes arm
  elevation and anticoagulation.

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Pseudomalfunction

• Pseudomalfunction is a type of output failure
  characterized by a phenomenon termed hysteresis.
  This occurs when a pacer is set to sense below
  the lower pacing rate limit.
• For example, if the lowest pacing rate programmed
  is 60 beats per minute (bpm), a pacer set to
  sense down to an intrinsic rate of 50 bpm, a
  hysteresis rate, begins to pace at 60 bpm when
  the patients intrinsic rate falls below 50 bpm.
  It continues to pace at the lower rate limit of
  the pacemaker, in this example 60 bpm, until it
  again senses intrinsic activity. This sensed
  event inhibits pacing, and the pacemaker again
  permits the intrinsic rate to go down to 50 bpm
  before pacing at 60 bpm.

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Pseudomalfunction

• Management of pacer output complications includes
  medications to increase the intrinsic heart rate
  and placement of a temporary pacer. A chest
  radiograph is warranted to check pacer leads,
  with close scrutiny to evaluate for possible lead
  fracture, which occurs most commonly at the
  clavicle/first rib location. The patients pacer
  identification card should be obtained and
  his/her electrophysiologist/cardiologist
  consulted.

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Thanks for Attending