Post-Anaesthesia Pulmonary Complications after Use of Muscle Relaxants (POPULAR): a Multicentre, Prospective, Observational Study

Kirmeier E, Eriksson LI, Lewald H et al.

Lancet Respiratory Medicine, Pre-published online September 2018. DOI:

Aim of Study

Establish whether use of neuromuscular blocking agents (NMBs) affects the risk of post-operative pulmonary complications, and if so whether this is mitigated by neuromuscular monitoring and use of reversal agents.

Design and Location

Prospective observational study of 22,000 patients in 28 hospitals across Europe.


Review of charts and physical examination of adults having GA for inpatient non-cardiac surgery (excluding ICU patients).

5 sub-groups: all GAs, GAs with neuromuscular blocking agent, GAs with neuromuscular monitoring, GAs with quantitative neuromuscular monitoring , GAs receiving a reversal agent.

Primary Outcome

Incidence of post-operative pulmonary complications.

Secondary Outcome

Incidence of intermediate or severe post-op pulmonary complications.


Multivariate analysis using logistic regression, accounting for cofactors, to produce odds ratios for each parameter.


Incidence of any post-op pulmonary complications in ‘all GAs’ group 7.6%; incidence of intermediate or severe post-op pulmonary complications 4.7%.

Risk of post-op pulmonary complications increased with use of NMBs – odds ratio 1.86.  Even single dose NMB increases risk with odds ratio of 1.53.

This is not mitigated by use of qualitative or quantitative neuromuscular monitoring, or reversal with neostigmine or sugammadex.

The effect is smaller than observed with other risk factors e.g. open upper abdominal or thoracic surgery, ASA grade, pre-op sats <94%.


Anaesthetists must balance the risk of post-operative pulmonary complications from NMB use against benefit of improved surgical conditions and intubating conditions.

Where possible/appropriate, suggest that NMBs are avoided.

Stated Limitations from the Study

Unable to statistically separate endotracheal intubation from use of NMBs as most patients were intubated, and very few (2.7%) were intubated without muscle relaxant.

Did not assess safety of intubating without NMB, or risk of iatrogenic injury from suboptimal surgical conditions.

Did not collect data on mode of intra-op ventilation.

Discussion from Journal Club Meeting (?Change of Practice)

Speculated as to why risk not mitigated by sugammadex – does this suggest that the effect is an association rather than causation, is the reversal insufficient, or has the harm already taken place?

Discussed importance of maintaining lung protective ventilation around extubation.

Discussed higher rate of intubation (81% of sample) than we would expect – is practice in the rest of Europe different to the UK?

Summary by Dr C Webb. Journal Club Meeting 06 December 2018.

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