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.