Hoist failure during recovery transfer in an anaesthetised horse: a near miss analysed through a Safety-II lens.

Hoist failure during the transfer of an anaesthetised horse created a high-risk near-miss event, which was successfully managed without injury. The incident was analyzed using a Safety-II approach to understand how adaptive team performance and organizational learning contributed to safety and improvement.

Case Description

• A 660 kg, 11-year-old Irish Sport Horse gelding underwent general anaesthesia for an emergency exploratory laparotomy lasting about 5 hours.
• During transfer to the recovery area using a ceiling-mounted powered hoist, the hoist failed mechanically and lost electrical power while the horse was suspended 150 cm above the floor.
• The horse remained suspended for approximately 10 minutes and could not be moved using the hoist’s standard controls.
• Team activity paused, roles were clarified: the anaesthesia resident maintained anesthetic depth and ventilation, while the medical team prepared an operating table to catch/support the horse.
• Physiological monitoring was limited to assessment of anaesthetic depth and pulse, which remained stable throughout the suspension.
• The operating table was raised to support the horse; hobbles were cut, and the horse was transferred to an alternative recovery box where assisted recovery was completed safely without injury.

Incident Analysis and System Factors

• The case was reviewed via a no-blame morbidity and mortality conference including clinical and management staff.
• The event was classified as a high-risk near-miss patient safety incident.
• Latent system vulnerabilities identified:
• Reliance on a single powered hoist without a manual override mechanism.
• History of intermittent malfunctions of the hoist prior to the failure.
• Limited formal training for staff on hoist operation and emergency procedures.
• Event occurred out-of-hours when support and staffing may be reduced.

Organisational Response

• Maintenance review and improvements were initiated for hoist reliability.
• Development and implementation of simulation training for staff on hoist use and emergency protocols.
• Revision of transfer protocols to include contingencies for equipment failure.
• Proposal to upgrade the hoist system to include manual override capabilities and improved safety features.

Safety-II Perspective

• Safety-II focuses on understanding how everyday system flexibility and team adaptability contribute to safety, rather than only investigating failures.
• This incident highlighted how coordinated teamwork, clear role allocation, and improvisation prevented harm despite equipment failure.
• The ability of the clinical team to adapt under pressure and the organizational learning that followed transformed a potentially dangerous event into a learning opportunity.
• The Safety-II lens emphasizes proactive system improvements and resilience rather than just root-cause blame after adverse events.