The effects of depth of volatile general anaesthesia, measured by bispectral index (BIS), on post-operative pain.

Status

Recruiting

Phases

Unknown

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12609000350224

Enrollment

150

Registered

2009-05-25

Start date

2009-12-01

Completion date

Unknown

Last updated

2020-01-13

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

Conditions

None listed

Brief summary

Recent studies have shown that the amount of general anaesthesia administered during an operation may influence pain and pain relief needed after surgery. We plan to use a brain monitor called bispectral index (BIS) to investigate a possible relationship between general anaesthesia and pain after surgery. We also plan to further investigate whether differing intensity of post-operative pain is influenced by either different genetic sensitivity to pain, or the body excreting fentanyl more quickly.

Interventions

The treatment group will receive deeper planes of volatile general anaesthesia for the duration of surgery with a bispectral index (BIS) targeted at 30-40. (ie the dose of volatile general anaesthesia will be titrated to the BIS)

Study design

Allocation

Randomised controlled trial

Intervention model

Parallel

Primary purpose

Prevention

Masking

Blinded (masking used)

Eligibility

Sex/Gender

All

Age

18 Years to 65 Years

Healthy volunteers

Yes

Inclusion criteria

Patients scheduled for elective surgery with a non-malignant diagnosis, aged 18-65 years, American Society of Anaesthesiologists score (ASA) 1 or 2, competent to consent to participation, able to use and visual analogue scale (VAS) and able to activate a patient controlled analgesia (PCA) machine post-operatively.

Exclusion criteria

Emergency surgery Age greater than 65 years Age less than 18 years. ASA 3 or above. Inability to consent or lack of written consent Inability to speak English fluently Malignancy diagnosed or suspected pre-operatively Epilepsy, neuromuscular disease, psychiatric illness or COPD with carbon dioxide retention Pre-operative chronic opioid use Morphine allergy, allergy to drugs used as part of the standardised general anaesthetic, history of malignant hyperthermia Use of regional anaesthesia or neuraxial blockade (or request for regional anaesthesia by patient) Use of TIVA rather than volatile general anaesthesia Protocol broken intra-operatively (or post-operatively) Return to theatre for re-operation within 48 hours Pregnancy Severe asthma Expected duration of surgery > 3 hours (180 minutes) Obesity (Weight > 120kg or body mass index (BMI) >35 kg/m2)

Outcome results