14.3 Reporting Pre-incision Baselines

14.3 Reporting Pre-incision Baselines

Quick Answer: After anesthesia and positioning stabilize, obtain reproducible pre-incision baselines, then confirm/report/document their quality with the interpreting physician and surgical team using closed-loop acknowledgment. Report objective signal status—not an independent diagnosis.

Baselines are the reference for every later alert. Reporting them is not a courtesy announcement; it is the shared starting line for Domain II recognition and Domain IV communication. If the team never hears that lower-extremity SSEPs are barely reproducible, a later “loss” may be misread as sudden cord catastrophe—or ignored as “the signals were always bad.”

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When Baselines Are Ready to Report

Primary pre-incision baselines used for alert comparison are typically reported when:

• Induction is complete and the anesthetic regimen relevant to the modalities is reasonably stable
• Final surgical positioning is done (positioning itself can alter plexus and cord signals)
• Impedance/noise are acceptable and traces are reproducible
• Critical surgical maneuvers have not yet begun

Modality-specific nuances matter. TcMEPs require adequate recovery from neuromuscular blockade (train-of-four context) and an anesthetic plan compatible with myogenic responses. BAEP baselines need secure stimulus delivery. EMG “baselines” are often a quiet free-run reference plus documentation of spontaneous activity. Report what you actually have—not what a template assumes.

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What to Include in a Baseline Report

A useful baseline communication is structured and objective:

Quantify when you can (latencies, amplitudes, percent asymmetries), but do not invent precision you did not measure. If the interpreting physician uses specific alert criteria for the case, confirm that those criteria will be applied relative to these baselines.

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Confirm, Report, Document—With Both Audiences

Section 14.3 explicitly pairs interpreting physician and surgical team communication:

1. Confirm internally that traces are the intended baseline set (correct montage, side labels, gain, filters, averaging count).
2. Report to the interpreting physician (in-room or remote) for interpretive concurrence as your coverage model requires.
3. Report to the surgical team—often surgeon and anesthesiology—so operative decisions start from a shared picture.
4. Document the baseline status, time, and who was notified.

Closed-loop still applies. After stating baselines, seek acknowledgment: “Please confirm you received that lower-extremity cortical SSEPs are present but low amplitude bilaterally.” A nod from a scrubbed surgeon who did not hear you is not closed-loop.

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Technologist vs Interpreting Physician at Baseline

• Technologist: Verifies technical adequacy, describes what is present/absent/asymmetric, notes technical limitations, and communicates those facts.
• Interpreting physician: Judges whether baselines are clinically adequate for the planned surgery, may adjust vigilance or criteria, and advises the surgical team on interpretive implications.

Do not announce, “This means the cord is already damaged,” as a solo diagnostic pronouncement. You may say, “Left lower responses are markedly reduced compared with right and with typical amplitudes; I’ve notified interpreting and the surgeon.” Interpretation of pathologic significance is collaborative and physician-guided.

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Poor, Asymmetric, or Unobtainable Baselines

Not every patient produces textbook waveforms. Pre-existing neuropathy, prior injury, edema, noise, and anesthesia can degrade baselines. Communication priorities:

• Do not hide poor baselines to avoid delaying incision.
• Do escalate when a modality essential to the confirmed plan is unobtainable after reasonable troubleshooting.
• Do recalibrate expectations with the team: alert criteria still reference the patient’s own baseline, but absolute amplitudes may be small and SNR limited.
• Do document troubleshooting steps and the final baseline judgment.

Example closed-loop escalation: “I cannot obtain reproducible left lower MEPs after checking connections, bite block, anesthesia agents, and TOF. Interpreting recommends proceeding with SSEPs, right MEPs, and EMG while continuing attempts. Surgeon, do you want any change in surgical plan based on that limitation?”

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Anesthesia Partnership at Baseline Time

Baseline reporting often includes a brief anesthesia check-in because systemic variables define what “good” means:

• Volatile agent levels affecting cortical SSEPs/MEPs
• Neuromuscular blockade status for myogenic MEPs and triggered EMG
• Blood pressure, temperature, and positioning concerns already visible in signals

If baselines are poor because of a reversible anesthetic factor, say so objectively and request optimization before locking the reference—especially if critical risk is minutes away. That is communication, not practicing medicine in isolation: you are reporting monitoring constraints to the physicians who control those variables.

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Timing Relative to Incision and Exposure

Some teams refresh baselines after exposure when soft-tissue retraction or field conditions change the noise floor. Distinguish:

• Primary pre-incision baseline for the start of risk
• Post-exposure / pre-critical-maneuver updates when practice calls for them

Report updates with the same closed-loop discipline. Never silently replace the reference without telling interpreting coverage and the surgical team—otherwise later percent-change statements become meaningless.

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Documentation Anchors for Later Alerts

Baseline reporting feeds Chapter 15 documentation tasks. At minimum, the record should support later statements such as “amplitude fell 60% from the pre-incision baseline reported at 09:12.” Include modality, side, time, quality notes, and notification. Clear baseline communication is what makes real-time alerts (Section 14.4) intelligible rather than dramatic.

If you cannot summarize baseline status in one crisp closed-loop message, you are not ready for incision from a communication standpoint—even if electrodes are already placed.