By Alan R. Aitkenhead, BSc, MD, FRCA, Professor, Department of Anaesthesia, University of Nottingham Medical School, Nottingham, UK; Graham Smith, BSc(Hon), MD, FRCA, Professor of Anaesthesia, University Department of Anaesthesia, Critical Care and Pain Management, Leicester Royal Infimary, Leicester, UK; and David J. Rowbotham, MD, MRCP, FRCA, Professor of Anaesthesia and Pain Management, University Department of Anaesthesia, Critical Care and Pain Management, Leicester Royal Infirmary, Leicester, UK |