What are the steps in pacing a patient from applying chest pads onward?

Steps for Transcutaneous Cardiac Pacing from Pad Application Onward

For transcutaneous cardiac pacing, place pads in the anteroposterior position (one on the anterior chest, one on the back between the scapulae), start with 40-80 mA current, increase until electrical and mechanical capture is achieved, and ensure adequate sedation for patient comfort. 1, 2

Pad Preparation and Placement

Skin Preparation

• Rapidly wipe the chest to remove excess moisture or sweat if the patient is diaphoretic, but do not delay pacing 3
• Remove any transdermal medication patches from the pad placement sites, as they may block energy delivery 3
• If excessive chest hair is present, quickly remove it by briskly pulling off an electrode pad (which removes hair) or rapidly shaving, but only if this does not delay pacing 3

Optimal Pad Position

• Place pads in the anteroposterior (AP) position as the preferred approach—this requires 33 mA less energy to achieve capture compared to anterolateral positioning 2
• Position the anterior pad on the left anterior chest (avoiding breast tissue in women—place lateral to or underneath the left breast) 3
• Position the posterior pad on the back between the scapulae 2
• Ensure pads are at least 8 cm away from any implanted pacemaker or ICD device if present 3, 4
• Use adult-sized electrode pads (8-12 cm diameter) for adequate contact 3

Initiating Pacing

Starting Parameters

• Set the pacing rate to 60-80 beats per minute initially (adjust based on clinical need) 1
• Begin with a current output of 40-80 mA for most patients with minimal hemodynamic compromise 1
• Be prepared to use higher thresholds (up to 140 mA maximum on most devices) in patients with emphysema, pericardial effusion, or those receiving positive pressure ventilation 1

Achieving Capture

• Gradually increase the current (mA) until electrical capture is observed on the ECG monitor 1
• Confirm electrical capture by identifying a widened QRS complex followed by a distinct ST segment and broad T wave on the ECG 1
• Verify mechanical capture by palpating a pulse that corresponds with each paced beat—ECG evidence alone is insufficient 1, 5
• Note that intense muscle contractions may make pulse palpation difficult; consider using pulse oximetry or arterial line waveform if available 5

Patient Management During Pacing

Sedation and Analgesia

• Provide adequate sedation and analgesia immediately, as transcutaneous pacing causes significant discomfort from chest wall muscle contractions 1
• Expect more severe muscle contractions with the anteroposterior position (median severity score of 4 vs. 3 for anterolateral) 2
• Maintain sedation throughout the pacing period to ensure patient comfort 1

Monitoring and Adjustments

• Set the pacing output 5-10 mA above the capture threshold to maintain consistent capture 1
• Continuously monitor for loss of capture and be prepared to increase output if needed 1
• Assess hemodynamic response by monitoring blood pressure, mental status, and peripheral perfusion 1

Special Considerations and Pitfalls

When Pacing is NOT Indicated

• Do not use transcutaneous pacing as routine treatment in cardiac arrest with asystole or pulseless electrical activity (PEA)—it is not effective and will not improve outcomes 3, 6
• Electric pacing shows no benefit regardless of timing (early or delayed), location (in-hospital or out-of-hospital), or primary rhythm in cardiac arrest 3

Appropriate Clinical Scenarios

• Use transcutaneous pacing for severe symptomatic or hemodynamically unstable bradyarrhythmias with a pulse 1
• Consider it particularly useful for reversible conditions like digoxin toxicity or AV block with inferior MI 1
• Use as a bridge when transvenous pacing is not immediately available or carries high risk 1

Technical Challenges

• Be aware that the pacing impulse may cause electrical artifact on the ECG that obscures evidence of capture 5
• Recognize that failure to capture occurs in approximately one-third of patients even with optimal technique 5
• If capture cannot be achieved, prepare for alternative pacing methods (transvenous or epicardial if post-cardiac surgery) 3, 7