Comprehensive and Detailed Explanation From Exact Extract Without Links:

NCC and AWHONN teaching materials describe that butorphanol, an opioid analgesic, characteristically produces a transient sinusoidal-like pattern or pseudo-sinusoidal pattern with moderate variability preserved.

This drug-related pattern has:

• smooth, regular oscillations

• maintained variability

• absence of true periodic decelerations

• resolution within 20–60 minutes

Simpson & Menihan describe butorphanol as producing a “saw-tooth, wavering pattern” often mistaken for dysrhythmia but actually benign.

True sinusoidal patterns (e.g., fetal-maternal hemorrhage) are fixed, smooth, non-variable patterns with absent variability, not matching the scenario.

Atrial flutter produces very rapid atrial contractions, which manifest as irregular baseline spikes—also not consistent.

Therefore, the described tracing aligns most closely with butorphanol effects.