1. Regional techniques and outcome: what is the evidence?;Hanna;Curr Opin Anaesthesiol,2009
2. Outcome after regional anesthesia: weighing risks and benefits;Lirk;Minerva Anestesiol,2014
3. Clinical review: can we predict which patients are at risk of complications following surgery?;Shah;Crit Care,2013
4. A review of studies of anaesthetic risk, morbidity and mortality;Derrington;Br J Anaesth,1987
5. Complications and death following anaesthesia. A prospective study with special reference to the influence of patient-, anaesthesia-, and surgery-related risk factors;Pedersen;Dan Med Bull,1994