Using the qNOX Index to Predict Pain-Related Body Responses During General Anesthesia

Predictive Value of the qNOX Index for Nociceptive Hemodynamic Responses to Endotracheal Intubation and Surgical Incision During Sevoflurane General Anesthesia

Status

Not yet recruiting

Phases

Unknown

Study type

Observational

Source

ANZCTR

Registry ID

ACTRN12626000445370

Enrollment

Registered

2026-04-09

Start date

2026-04-30

Completion date

2026-06-30

Last updated

2026-06-15

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

The purpose of this study is to examine whether a brain-based monitoring measure (qNOX) can help predict how the body responds to painful stimuli during surgery performed under general anesthesia. Painful events such as placement of a breathing tube and the first surgical cut can cause increases in heart rate or blood pressure, even when patients are unconscious. This study will observe standard anesthetic care and record brain activity and routine vital signs during surgery, without changing treatment. The study hypothesis is that higher qNOX values are associated with a greater likelihood of pain-related changes in heart rate or blood pressure during these surgical events.

Interventions

This is a non-interventional, observational study. Participants will receive standard general anesthesia with endotracheal intubation as part of routine clinical care. Exposure involves intraoperative recording of EEG-derived indices (qNOX and qCON) during sevoflurane anesthesia to assess their association with pain-related hemodynamic responses to intubation and surgical incision. No additional treatments or procedures will be introduced. Duration of observation will be up to 1 hour.

Eligibility

Sex/Gender

All

Age

18 Years to 75 Years

Healthy volunteers

Inclusion criteria

Participants will be adults aged 18 to 75 years with an ASA physical status classification of I to III. Eligible participants will be scheduled for elective surgical procedures of moderate pain intensity under general anesthesia with endotracheal intubation and will be able to provide written informed consent.

Exclusion criteria

Participants will be excluded if they have neurological conditions that may affect EEG recordings, psychiatric disorders requiring ongoing treatment, or chronic use of opioids or benzodiazepines. Additional exclusion criteria include a body mass index greater than 35 kg/m², hemodynamic instability prior to induction of anesthesia, known allergy or contraindication to the study medications, emergency surgery, pregnancy, or breastfeeding.

Outcome results