Table 1.

Definitions of outcomes included from the UKOSS national studies

Condition	Definition
Peripartum hysterectomy	Any woman giving birth to an infant and having a hysterectomy during the same clinical episode
Peripartum haemorrhage	Cases were pregnant women of 20 weeks gestation or more identified as having >8 units of red blood cell transfusion within a 24 h period
Failed tracheal intubation	A case of failed intubation was defined as failure to achieve tracheal intubation during a rapid sequence induction for obstetric anaesthesia, thereby initiating a failed intubation drill
Severe sepsis	Any pregnant woman (up to 6 weeks postpartum) diagnosed with severe sepsis (irrespective of the source of infection). A severe sepsis case would be expected to include women in one of the following groups: Death related to infection or suspected infection Any women requiring level 2 or level 3 critical care (or obstetric HDU-type care) due to severe sepsis or suspected severe sepsis A clinical diagnosis of severe sepsis—based on two or more of the following: Temperature >38°C or <36°C measured on two occasions at least 4 h apart Heart rate >100 bpm measured on two occasions at least 4 h apart Respiratory rate >20/min measured on two occasions at least 4 h apart White cell count >17×109/L or <4×109/L or with >10% immature band forms, measured on two occasions

UKOSS, UK Obstetric Surveillance System; HDU, high dependency unit.