Twelve-Lead on Post-Operative Day 2 After Bypass Surgery
A 61-year-old man is on post-operative day 2 after coronary artery bypass grafting. He has a sternal incision with a bulky dressing, two chest tubes, and epicardial pacing wires coiled and taped to his abdomen. A PICC line with a transparent dressing sits in his left upper arm, and an automated BP cuff on his right arm cycles every 15 minutes. He is alert, HR 96, BP 132/80, and asks why "it takes so many stickers." The order is a routine post-operative 12-lead. The bed is at a 30-degree angle and he cannot tolerate being flat.
1. Where will you place the limb electrodes, and what must accompany the tracing?
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The standard wrist/ankle sites are impractical and unsafe here: the arms are occupied by a PICC dressing on the left and a cycling BP cuff on the right, and reaching his ankles means moving a fresh post-operative patient. Place the arm electrodes on the anterior shoulders (below the clavicle, lateral to the sternal dressing) and the leg electrodes on the lower abdomen/hips, avoiding the pacing-wire exit sites and the chest-tube insertion dressings.
This is a recognized modification, not a workaround to hide. The tracing must be labeled with the actual electrode locations, because shoulder/hip placement shortens the limb vectors and can alter amplitude and axis compared with standard placement - a later reader comparing this to a pre-operative EKG needs to know that the apparent axis shift may be positional.
Keep the arm electrodes off the PICC dressing itself (do not press on or peel it) and off the inflating cuff. Explain to the patient in plain language that you are placing them where his surgery allows.
2. The precordial leads cannot all sit in their standard positions because of the sternal dressing and chest tubes. What is acceptable, and what is not?
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Acceptable: place each precordial electrode as close to its standard anatomical landmark as the dressing and tubes allow, keeping the relative sequence V1 through V6 so the progression across the chest remains interpretable, and record exactly where each one actually sat.
Not acceptable: skipping leads, placing electrodes on a dressing, over broken or macerated skin, or tugging on chest tubes or pacing wires to get to a landmark. Never lift or peel the sternal dressing. Never allow a lead wire to tension a chest tube - a dislodged tube is a life-threatening event caused by your exam.
Judgment point: if V1 and V2 must shift laterally because of the dressing, R-wave progression and ST analysis in those leads are altered. The tech's job is not to hide this but to make it visible - document the actual positions and, if the provider needs true V1/V2, let them decide whether the dressing can be adjusted.
3. The BP cuff inflates in the middle of your acquisition and the tracing shows a burst of distortion. What is happening and what do you do?
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The cuff inflation produces movement and muscle artifact on the right arm lead, and possibly on adjacent leads - it is patient/equipment-source artifact, not a rhythm change. Recognize the timing coincidence: the distortion starts and stops with the cuff cycle.
Do not interpret through it, and do not simply apply a filter and keep the strip. Instead:
- Pause the acquisition, or ask the nurse whether the cuff cycle can be briefly paused or delayed - this is a routine post-op EKG, not a resuscitation, so a short coordination is safe.
- Re-acquire after the cuff deflates, with the patient's arm relaxed and supported.
- If the cuff cannot be paused, note on the tracing which lead(s) were affected and when, so no one calls a pseudo-arrhythmia or a pseudo-ST change.
The teachable point: artifact that is time-locked to an external device is almost never electrophysiologic. Fix the source before you touch the filter settings.