Anaesthesia in laboratory animals is a refinement priority under the Three Rs framework. Appropriate anaesthetic protocols minimise pain and distress during research procedures and improve animal welfare and data quality.
Anaesthesia quality in laboratory animals directly affects their welfare during and after procedures, and can affect the validity of research data through physiological perturbations caused by poor anaesthetic management. Hypothermia is the most common preventable complication in small rodents: without active thermal support, a mouse under isoflurane anaesthesia can lose several degrees of core temperature within minutes, causing cardiovascular compromise and prolonged recovery. Appropriate monitoring by trained staff significantly reduces anaesthetic mortality in all species. The ethical framework of the Animals (Scientific Procedures) Act 1986 requires that the severity of procedures including anaesthesia is minimised and that appropriate analgesics are used when procedures are expected to cause pain. Refinement guidance from the NC3Rs (National Centre for the 3Rs) provides detailed evidence-based protocols for common laboratory species.