4.4 Artifact Recognition, Troubleshooting & ECG Dysrhythmias

4.4 Artifact Recognition, Troubleshooting & ECG Dysrhythmias

During polysomnographic recording, the technician must maintain pristine signal quality by identifying and resolving non-physiological artifacts that obscure sleep architecture. Simultaneously, the technician must continuously monitor the patient's single-lead electrocardiogram (ECG) to identify life-threatening cardiac dysrhythmias. On the Certified Polysomnographic Technician (CPSGT) examination, troubleshooting skills and cardiac emergency protocols represent high-yield core competencies.

---

1. Polysomnographic Artifact Recognition & Troubleshooting

Artifacts are unwanted electrical, mechanical, or biological potentials superimposed upon true physiological recordings.

+-----------------------------------------------------------------------------+
|                   COMMON POLYSOMNOGRAPHIC ARTIFACTS                         |
|                                                                             |
|   [1] 60 Hz Interference   ---> Continuous dark sinusoidal 60-cycle band    |
|   [2] Sweat / Galvanic     ---> Slow, undulating baseline sway (0.1-0.5 Hz) |
|   [3] ECG Crosstalk        ---> Periodic sharp spikes time-locked to QRS    |
|   [4] Pulse / Vascular     ---> Smooth rolling waves delayed ~100-200ms QRS |
|   [5] Muscle (EMG) Fuzz    ---> High-frequency jagged spikes (>30 Hz)       |
|   [6] Electrode Pop        ---> Abrupt vertical square/triangular jump      |
+-----------------------------------------------------------------------------+

Detailed Artifact Breakdown & Step-by-Step Resolution:

---

2. Cardiac Dysrhythmia Recognition in Polysomnography

Sleep technologists continuously monitor single-lead ECG (Modified Lead II) to evaluate baseline cardiac rhythm and detect sleep-related arrhythmogenesis.

+-----------------------------------------------------------------------------+
|                    AASM CARDIAC DYSRHYTHMIA DEFINITIONS                     |
|                                                                             |
|   SINUS BRADYCARDIA:     Heart rate < 60 bpm in adults                      |
|                          Severe / Critical: Heart rate < 40 bpm             |
|   SINUS TACHYCARDIA:     Heart rate > 100 bpm in adults                     |
|   ASYSTOLE / PAUSE:      Cardiac flatline / absence of QRS >= 3.0 seconds   |
|   PREMATURE ATRIAL (PAC):Early abnormal P wave with narrow normal QRS       |
|   PREMATURE VENTR. (PVC):Early wide (>120 ms) bizarre QRS without P wave    |
|   ATRIAL FIBRILLATION:   Irregularly irregular R-R intervals; absent P waves|
|   VENTRICULAR TACH (VT): Run of >= 3 consecutive wide PVCs at rate > 100 bpm|
|   VENTRICULAR FIB (VF):  Chaotic, disorganized baseline; no cardiac output  |
+-----------------------------------------------------------------------------+

Morphological Patterns of Premature Ventricular Contractions (PVCs):

• Unifocal PVCs: All PVCs exhibit identical morphology, indicating origin from a single ectopic ventricular focus.
• Multifocal PVCs: PVCs exhibit differing morphological shapes and polarities, reflecting multiple irritable myocardial foci (higher clinical risk).
• Ventricular Bigeminy: Alternating pattern where every normal sinus beat is paired with one PVC ($1:1$ ratio).
• Ventricular Trigeminy: Repetitive pattern of two normal sinus beats followed by one PVC ($2:1$ ratio).
• Ventricular Couplet: Two consecutive PVCs occurring in rapid succession.
• Non-Sustained Ventricular Tachycardia (NSVT): A run of 3 or more consecutive PVCs lasting $< 30\text{ seconds}$ at a rate $> 100\text{ bpm}$.
• Sustained Ventricular Tachycardia (SVT): VT lasting $\ge 30\text{ seconds}$ or producing immediate hemodynamic instability.

+-----------------------------------------------------------------------------+
|                        PVC PATTERN CLASSIFICATION                           |
|                                                                             |
|   BIGEMINY:    [ Normal ] ──> [ PVC ] ──> [ Normal ] ──> [ PVC ]            |
|   TRIGEMINY:   [ Normal ] ──> [ Normal ] ──> [ PVC ] ──> [ Normal ]         |
|   COUPLET:     [ Normal ] ──> [ PVC ] ──> [ PVC ] ──> [ Normal ]            |
|   RUN OF VT:   [ Normal ] ──> [ PVC ] ──> [ PVC ] ──> [ PVC ] ...           |
+-----------------------------------------------------------------------------+

---

3. Emergency Escalation Protocols & Clinical Response

When cardiac dysrhythmias occur, sleep technologists follow a three-tiered escalation framework based on clinical severity and patient stability.

+-----------------------------------------------------------------------------+
|                 POLYSOMNOGRAPHIC CLINICAL ESCALATION TIERS                  |
|                                                                             |
|   TIER 1: ROUTINE / DOCUMENTATION ONLY                                      |
|   - Isolated unifocal PACs or PVCs (< 6/min)                                |
|   - Mild sinus bradycardia (50-59 bpm) during N3 in healthy patient         |
|   - Transient post-apnea tachycardia (100-110 bpm)                          |
|   --> ACTION: Document in tech log; include epoch timestamps.               |
|                                                                             |
|   TIER 2: URGENT / PHYSICIAN NOTIFICATION                                  |
|   - New-onset Atrial Fibrillation with rapid ventricular response (>120 bpm)|
|   - Frequent multifocal PVCs, bigeminy, or couplets                         |
|   - Sustained sinus bradycardia < 40 bpm or sinus tachycardia > 130 bpm     |
|   - Asymptomatic sinus pauses between 3.0 and 5.0 seconds                   |
|   --> ACTION: Monitor closely, check patient vitals, notify on-call physician|
|                                                                             |
|   TIER 3: LIFE-THREATENING EMERGENCY (CODE BLUE / 911)                      |
|   - Sustained Ventricular Tachycardia (VT)                                  |
|   - Ventricular Fibrillation (VF)                                           |
|   - Asystole >= 5.0 to 6.0 seconds or any asystole with unresponsiveness   |
|   - Acute signs of Myocardial Infarction / Severe chest pain / Shock        |
|   --> ACTION: Immediate in-room assessment, initiate CPR/BLS, call EMS/Code|
+-----------------------------------------------------------------------------+

Step-by-Step Life-Threatening Emergency Algorithm:

1. Immediate In-Room Assessment: Enter the room immediately; check responsiveness (tap and shout) and check carotid pulse and breathing simultaneously for no more than 10 seconds.
2. Call for Immediate Help & Activate EMS / Code Blue: If unresponsive and pulseless, shout for assistance, activate the facility emergency alarm, and dial 911 / internal hospital code line.
3. Initiate High-Quality Basic Life Support (BLS):
   • Place patient on firm surface (or insert backboard).
   • Begin high-quality chest compressions: rate of $100\text{ to } 120\text{ compressions/minute}$, depth of $2.0\text{ to } 2.4\text{ inches}$ (5–6 cm), allowing complete chest recoil.
   • Retrieve and attach the Automated External Defibrillator (AED) immediately; follow voice prompts to shock shockable rhythms (VF or Pulseless VT).
   • Deliver ventilations with bag-valve-mask (30 compressions : 2 breaths) if trained.
4. Document & Hand Off: Maintain precise chronological log of event start time, CPR initiation, shocks delivered, and hand off directly to arriving paramedics/code team.