Transcript (pps, 9.10 MB)

Noninvasive
Pacing –
What You
Should Know
Hey!
Maybe we
should try
pacing!
Evidence Based Medicine
What articles or literature support the
use of pacing in the Pre-hospital arena?
The Original
Pacing Study!
Other Important Papers on Pacing
• “Prehospital TCP for
symptomatic
bradycardia”
• Pacing and Clinical
Electrophysiology, 1991
• 51 pts tot., 27 paced
• Survival to dischg if
palpable pulse on
paramedic arrival? 80%
in TCP vs 0% (p=0.02)
• TCP clearly benefits the
bradycardic pt with pulse
• “The Benefits of
Electricity: TCP in EMS”
• Emerg. Med. Svcs, 2002
• Informational article
supporting the use of
TCP in the bradycardic
patient and now also in
children
ACLS Guidelines
• Last revised in 2005
• Emphasis on early pacing for symptomatic
bradycardia
• Initial pacing method of choice in emergency
cardiac care
• Quickly initiated and least invasive
Cardiac Conduction System
Sinoatrial (SA) Node
Atrioventricular (AV) Node
Left Bundle Branches
Right Bundle Branch
Purkinje Fibers
P
T
QRS
P = Atrial Depolarization
QRS = Ventricular Depolarization
T = Ventricular Repolarization
Failure of the Conduction System
• May occur anywhere in the system
• The farther down the system –
the slower the heart rate
• Multiple causes
• Results
– bradycardia
– asystole
Treatment of Symptomatic
Bradycardia
• Atropine
• Noninvasive pacing (Class 1 intervention)
• Dopamine
• Epinephrine
Asystole
• Pacing is no longer recommended for aystole
MVEMSA Pacing Protocol
•
INDICATIONS:
– Symptomatic Bradycardia
– 3rd degree Complete Heart Block or 2nd degree Mobitz
type 2
•
RELATIVE CONTRAINDICATIONS:
– Hypothermia
– Hemodynamically stable awake patients.
– Non-intact skin at the site of the electrode placement
Temporary Pacing Techniques
Epicardial
Transesophageal
Trancutaneous
Noninvasive Pacing
• Self-adhesive electrodes applied to the skin
• Advantages
– easily initiated by nurse, paramedic and MD
– not invasive/cost effective
– used when invasive pacing is
contraindicated / undesirable
• Disadvantages
– discomfort
Applications for Noninvasive
Pacing
• Emergency Use
• Alternative to invasive pacing
• Standby Use
Emergency Use of Noninvasive
Pacing
• Therapeutic bridge to stabilize the patient and
plan further care
– symptomatic bradycardia unresponsive to
drugs
– cardiac arrest
Standby Use of Noninvasive
Pacing
• Patient is clinically stable but may
decompensate
– cardiac patient undergoing surgery
– acute MI with heart block
– permanent pacemaker surgery
– cardiac catheterization/angioplasty
– post cardioversion bradycardias
• We WILL NOT be using Pacing for these
purposes!
Pacing Procedure
• Preparing the patient and family
• ECG electrode placement
• Pacing electrode placement
• Selecting the rate, mode and current
• Assessing for capture
Preparing the Patient and Family
• Explain procedure
– discomfort with cutaneous nerve
and skeletal muscle stimulation
• Sedation or analgesia often needed
ECG Electrodes
• Skin prep
– remove excessive
chest hair
– clean, dry, and gently
abrade skin
• Place ECG electrodes
away from pacing electrodes
• Use quality ECG electrodes
Pacing Electrodes
• Skin prep important
– clip excessive chest hair
– clean skin with soap and water
– dry skin and gently abrade
• Place pacing electrodes on clean, dry skin
Anterior-Posterior Electrode Placement
• Most common
placement
• Preferred
• Improves conduction to myocardium
Anterior Electrode Placement
Posterior Electrode Placement
Anterior-Posterior Electrode Placement
Anterior-Lateral Electrode Placement
• Alternate placement
• Convenient placement
in cardiac arrest
• Usually the SECOND choice
Anterior-Lateral Electrode Placement
Noninvasive Pacing Modes
• Demand
• Non-demand
(asynchronous or fixed)
MVEMSA Protocol
• Assemble the required equipment.
• Explain the procedure to the patient.
• Connect the patient to a cardiac monitor
and obtain a rhythm strip.
• Obtain baseline vital signs.
MVEMSA Protocol
• Provide for patient sedation using Versed 2mg slow IV
push, titrate in 1 mg increments, to a maximum of 6mg. DO
NOT delay pacing to give sedation if the patient is critically ill
and such delay may cause a detriment in patient’s care.
• Apply pacing electrodes (avoid large muscle masses) and
attach the pacing cable and pacing device, per
manufacturer’s recommendations.
• Select the pacing mode to demand or non-demand mode, if
applicable.
• Set the pacing rate to 80 BPM.
• Set the milliamps (mA) at zero.
MVEMSA Protocol
• Activate the pacing device and increase the
milliamps as tolerated (observe the patient
and ECG) until capture is achieved
(capture is the point when the pacemaker
produces a pulse with each QRS complex).
• Obtain rhythm strips as appropriate.
• Continue monitoring the patient and
anticipate further therapy.
Demand pacing
• Delivers impulse only when needed
• Sensing inhibits pacemaker
• Not used in Pre-hospital environment
Non-demand Pacing
• Delivers current at selected rate and ignores
intrinsic beats
• Backup mode for oversensing and motion artifact
Selecting Rate and Current
• Assure proper QRS sensing
• Set pace rate high enough for adequate perfusion
• Increase current (mA) until electrical capture
Access Pacer (Green) mode (Zoll)
The Pacer (Green) mode is
accessed by turning the
Selector Switch counterclockwise
Milliamps are the type of current
which are utilized in this mode
No AED capability or ANALYZE
button can
be used in this mode
Pacer Mode:
Rate Dial
• Pacer markers (PPM)
indicate the rate set to
attempt to capture the
ventricle
• Default settings of 70
PPM and 0 mA are
displayed upon access of
Pacer Mode
• To increase or decrease
pacer marker (PPM) turn
the Pacer Rate Dial
Pacer Mode:
Output Dial
• Turn the Pacer Output
dial to adjust the level of
discharged milliamps.
• If capture is achieved, the
PPM will have a wide
complex reflecting
ventricular contraction
following the thin PPM
rate marker
Assessing for Capture
• Electrical capture
– depolarization of the ventricles
– confirmed by ECG display
• Mechanical capture
– contraction of the myocardium
– confirmed by pulse and improved
cardiac output
• Both must occur to benefit the patient
Electrical Capture
Electrical Capture
Electrical Capture
Intermittent Electrical Capture
Intermittent Electrical Capture
Determining Mechanical Capture
• Check pulse
(Doppler helpful)
• Look for increase in
blood pressure
Determining Mechanical Capture
• Use of pulse
oximetry during
pacing may assist
in determining
capture
• PLEASE DON’T
FORGET THIS
IMPORTANT POINT!
Pacemaker Blanking Periods
Artifact During Pacing
• Artifact may mimic electrical capture
Artifact During Pacing
• Artifact may mimic electrical capture
Artifact During Pacing
• ECG electrodes pick up artifact from pacing current
• Artifact is sometimes displayed on monitor
• May mask VF and distort response to pacing
• Blanking period attempts to filter out artifact and
limit distortion of ECG signal
Troubleshooting
• Discomfort
• Failure to capture
• Undersensing
• Oversensing
Discomfort
• Explain procedure
• Reposition anterior electrode
• Use sedation or analgesia
Failure to Capture
• Increase current
• Reposition electrode across precordium
• Correct metabolic acidosis, hypoxia
• Check pacemaker function
Factors Possibly Leading To High
Capture Thresholds
• Hypoxia
• Acidosis
• Air, fluid in the chest
• Emphysema, pericardial effusion
• Positive pressure ventilation
• Ischemia
• Mild Hypothermia
Undersensing
• Increase ECG size
• Select different ECG lead
• Reposition ECG electrodes
• Re-prep skin and replace ECG electrodes
Oversensing
• Decrease ECG size
• Select different ECG lead
• Reposition ECG electrodes
• Select non-demand mode if available
Pacing Success
Summary - Noninvasive Pacing
• Valued and respected technique in
emergency cardiac care
• Basic principles of invasive pacing
apply to noninvasive pacing
• Allows rapid initiation of emergency pacing
“Buying Time”