SNaPP Study

Outcomes

The SNaPP study recruited 3,500 patients across 44 hospitals in Australia, Aotearoa New Zealand and Hong Kong, completing recruitment in July 2025, one year ahead of schedule. The trial compared sugammadex with neostigmine for reversal of neuromuscular blockade in adults aged 40 years and older undergoing major abdominal or thoracic surgery.

Published in The Lancet Respiratory Medicine in June 2026, the trial found that sugammadex reduced the incidence of postoperative pulmonary complications or death compared with neostigmine (19.0 per cent versus 21.5 per cent; risk ratio 0.88, 95 per cent CI 0.77–1.00; p=0.049). The reduction was small and was primarily driven by a lower incidence of atelectasis. Sugammadex was also associated with more complete reversal of neuromuscular blockade, less need for further reversal and shorter times to extubation. Other secondary outcomes, including postoperative nausea and vomiting, days alive and at home at 30 days, and health-related quality of life at three months, were similar between groups.

The findings indicate that sugammadex can be considered as a first-line drug for reversal of rocuronium- or vecuronium-induced neuromuscular blockade in older adults undergoing major abdominal or thoracic surgery. The longer-term clinical significance of the reduction in atelectasis remains uncertain.

Thank you

Many thanks to the many people and teams who contributed to the SNaPP trial, including the statistical team led by A/Prof Sabine Braat, the trial coordinating team led by Sofia Sidiropoulos, the Royal Melbourne Hospital Human Research Ethics Committee, and the ANZCA CTN Office team led by Karen Goulding.

Special thanks also go to Professor David A. Scott AM, Chair of the Data Safety Monitoring Committee; Dr Daniel Steinfort, Chair of the Endpoint Adjudication Committee; Adam Meehan, database lead; and the trial steering committee, including senior author Professor David Story and the community representatives.

In particular, we acknowledge the investigators and trial coordinators across the ANZCA Clinical Trials Network for their expertise, dedication and collaboration. We also thank ANZCA and FPM fellows for their ongoing support of CTN research through their subscriptions and donations to the ANZCA Foundation.

Media release

Check out our media release, Global study highlights hidden pandemic of lung complications, and news item.

Topmed Talk

A podcast interview with Professor Kate Leslie AO is available on TopMedTalk.

Video presentation

A video presentation of the results is now available.

Summary 

We completed recruitment of 3,500 patients on 3 July 2025 (23 months and 14 days) at 44 sites in Australia, Aotearoa New Zealand and Hong Kong. This is nearly a year ahead of schedule. The results have now been published in The Lancet Respiratory Medicine.

We designed a large simple trial investigating an interesting and important research question. Our trial had broad eligibility criteria, simple trial processes and a user-friendly database. We credit the rapid completion of the trial to the experience and expertise of our trial coordination team at the University of Melbourne; the extensive networks of sites and investigators created and supported by the ANZCA Clinical Trials Network; the dedication and hard work of our site investigators and trial coordinators, and the willingness of our patients to participate in the trial. 

Study summary
The SNaPP Study is a multicentre, double-blind, randomised clinical trial examining the effect of reversal of neuromuscular blockade on postoperative outcomes. Adult patients having abdominal or thoracic surgery under general anaesthesia will be randomised to sugammadex or neostigmine for reversal of neuromuscular blockade. The primary outcome is a composite of death or postoperative pulmonary complications up to hospital discharge (or postoperative day 7 if still in hospital).

Eligibility
Patients aged 40 years and over, scheduled for abdominal or thoracic surgery under relaxant general anaesthesia with an endotracheal tube, with expected operative time of ≥2 hours and hospital stay ≥1 postoperative night.

Study intervention
Sugammadex or neostigmine for reversal of neuromuscular blockade.

Primary endpoint
A composite of death or postoperative pulmonary complications up to hospital discharge (or postoperative day 7 if still in hospital).

Secondary endpoints
Secondary endpoints include components of the composite primary outcome, postoperative nausea and vomiting, unplanned ICU/HDU admission, days alive and at home, and change in health-related quality of life. Exploratory endpoints include duration of post anaesthesia care unit stay, airway instrumentation in the post anaesthesia care unit, change in quality of recovery score, change in frailty and severity of postoperative pulmonary complications. A health economic analysis is also planned.

Safety endpoints
A comprehensive set of events will be recorded as trial safety endpoints.

Sample size
3,500 patients.

Study duration
Four years.

Funding 

Medical Research Future Fund grant $2,948,208.65 (2023-2027)
The Australian and New Zealand College of Anaesthetists Foundation (2020) (CTN pilot study) $10000

Operations committee

Professor Kate Leslie AO FAHMS
Professor David Story
A/Professor Jai Darvall
Professor Philip Peyton
Ms Sofia Sidiropoulos

Collaborators

The University of Melbourne (Administering institution)
Australian and New Zealand College of Anaesthetists Clinical Trials Network (ANZCA CTN)

Endorsements

Australian and New Zealand College of Anaesthetists Clinical Trials Network (2020).

Trial registration

ANZCTR identifier: 12623000394640

Participating hospitals

Get in contact

Please email Sofia Sidiropoulos for any further information about the SNaPP Study.

Publications

Leslie K, Chan MTV, Darvall JN, et al. Sugammadex, neostigmine and postoperative pulmonary complications: an international randomised feasibility and pilot trial. Pilot Feasibility Stud 2021; 7: 200.

Leslie K, Braat S, Darvall JN, Peyton PJ, Devlin N, Myles PS, Corcoran TB, Short TG, Chan MTV, Olesnicky BL, Tran-Duy A, Maxwell-Wright H, Schultz-Ferguson C, Sidiropoulos S, Story DA. Sugammadex, neostigmine, and postoperative pulmonary complications: protocol of the SNaPP multicentre randomised controlled trial. BJA Open. 2026 Feb 10;17:100531. doi: 10.1016/j.bjao.2026.100531. PMID: 41716251; PMCID: PMC12914678.