General Anaesthesia Trials

 

ENIGMA 2007

Question

Nitrous oxide and post-op complications

Type

·      Multi-centre, partially-blinded RCT

Subjects

·      Major surgery (>2h surgery, >3d admit)

Groups

·      N2O/O2 70/30 vs N2/O2 80/20

↑Risk of

·      PONV

·      Wound infection

·      Pneumonia

·      Atelectasis

↔Risk of

·      Duration of hospital stay (primary outcome)

·      Mortality (but trend)

·      AMI (trend, and supported by an associated study)

·      VTE (but trend)

Problems

·      Complication detection bias

·      Was the badness due to ↑N2O or ↓O2?

 

ENIGMA 2 2014

Question

Nitrous oxide and safety

Type

·      Multi-national, assessor-blinded RCT

Subjects

·      Known or suspected CAD

Groups

·      N2O/O2 70/30 vs N2/O2 70/30 (i.e. O2-matched)

↑Risk of

·      PONV (but easily treatable)

↔Risk of

·      Mortality

·      AMI

·      Stroke

·      Wound infection

 

GAS 2019

Question

General anaesthetic toxicity in kids

Background

·      Animal studies suggest anaesthesia is neurotoxic to neonates (but different neuronal proliferation timelines)

·      Children undergoing many GAs don’t do as well (but confounders++)

Type

·      Multi-national, assessor-blinded RCT

Subjects

·      Otherwise healthy infants undergoing inguinal hernia repair

Groups

·      Spinal vs GA

Upshot

·      No difference in IQ at 2y and 5y

·      Reassuring if single GA <1 hour

 

BALANCE 2019

Question

BIS 50 vs 35

Type

·      Multi-national, partially-blinded RCT

Subjects

·      ASA 3-4, major surgery, high risk of Cx

Upshot

·      Mortality

·      Major complications e.g. AMI, PE, stroke

·      Awareness

·      No point sailing close to the wind

 

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