The introduction and evaluation of universal umbilical cord blood gas or lactate analysis into metropolitan and regional primary and secondary level maternity units in Western Australia

[Truncated abstract] Perinatal hypoxic-ischaemic injuries have significant medical, legal, financial, and social implications for the healthcare sector extending to families and the wider community. Consequences of in-utero exposure to hypoxic-ischaemic insults exist along a continuum ranging from no sequelae to extensive and debilitating long-term conditions including cerebral palsy and perinatal death. Biochemical data provided by umbilical cord blood-gas analysis (UCBGA) is integral to the diagnosis of perinatal hypoxic-ischaemic insults; the absence of umbilical artery metabolic acidaemia effectively excludes the diagnosis of intrapartum asphyxial injury. There is increasing support to perform UCBGA at delivery. In addition to the medicolegal benefits, recent data have demonstrated that the introduction of universal UCBGA into a tertiary maternity unit resulted in reduced rates of metabolic acidaemia and nursery admissions. Despite these potential benefits, there are a number of technical, financial and institutional challenges associated with introduction of this technique into clinical care. This thesis has two components: 1) the evaluation of the methodological challenges of UCBGA in a clinical environment, and 2) a detailed appraisal of the impact of introducing UCBGA into clinical care. The first experimental chapter of this thesis presents a randomised controlled trial evaluating four approaches to minimise the effect of delay on sampling accuracy. If analyses cannot be performed within minutes of delivery, cord blood samples should be stored in syringes at room temperature. This enables analyses to be delayed up to sixty-minutes without any significant changes in pH and base-excess levels. If lactate levels are measured, irrespective of the approach taken to maintain sample accuracy, processing is required within 15 minutes to prevent significant changes. The collection of paired arterial and venous samples from the umbilical cord is challenging; inaccurate sampling has been reported in 5-50% of samples. The second experimental chapter of this thesis evaluated a number of approaches to confirm that 'valid' paired samples were collected. A new simple algorithm was developed that can be universally applied to identify non-physiological UCBGA values...