Computer based haemodynamic guidance system is effective and safe in management of postoperative cardiac surgery patients.

A circulatory guidance system, Navigator, was evaluated in a prospective, randomised control trial at six Australian university teaching hospitals involving 112 scheduled postoperative cardiac surgical patients with pulmonary artery catheters placed and receiving 1:1 nursing care. The guidance system was used to achieve and maintain physician-designated cardiac output and mean arterial pressure targets and compared these with standard post open-heart surgery care. The primary efficacy endpoint was the standardised unsigned error between the targeted and the actual values for cardiac output and mean arterial pressure, time averaged over the duration of cardiac output monitoring - the average standardised distance. This was 1.71 (SD=0.65) for the guidance group and 1.92 (SD=0.65) in the control group (P=0.202). Rates of postoperative atrial fibrillation, adverse events, intensive care unit and hospital length-of-stay were similar in both groups. There were no device-related adverse events. Guided haemodynamic therapy with the Navigator device was non-inferior to standard intensive care unit therapy. The study was registered with ClinicalTrials.gov Identifier NCT00468247.

Non-invasive cardiac output measurement using a fast mixing box to measure carbon dioxide elimination.

This study investigated the accuracy of a new technique for measuring cardiac output using the derivative Fick principle based on the ratio of change in the partial pressures of end-tidal and mixed expired carbon dioxide produced by short periods of partial rebreathing. A prospective clinical study involving 24 patients following cardiopulmonary bypass for coronary artery bypass grafting or valvular surgery was undertaken in the intensive care unit of a university-affiliated hospital. Haemodynamic measurements were performed after admission to the intensive care unit. Cardiac output was measured simultaneously by bolus pulmonary artery thermodilution and by a non-invasive carbon dioxide partial rebreathing technique. Cardiac output measurement using the new technique demonstrated a significant but consistent underestimate, with a bias of -0.60 +/- 0.87 l/min. This new adaptation of the partial rebreathing technique is reliable in measuring cardiac output in postoperative patients. Reasons for the consistent discrepancy between thermodilution and partial rebreathing techniques are discussed.

Prenatal diagnosis in factor XIII-A deficiency.

Congenital factor XIII deficiency is a severe bleeding disorder that is inherited as an autosomal recessive trait. The condition is commonly due to absence of the factor XIII-A subunit protein in the plasma. The case of a baby is reported who showed typical clinical features of factor XIII-A deficiency, including recurrent bleeding from the umbilical stump and a life threatening haemorrhage after circumcision. Family studies were performed and molecular analysis, using a Short Tandem Repeat (STR) marker closely linked to the A subunit gene, allowed antenatal exclusion diagnosis to be undertaken in a subsequent pregnancy. The case highlights the importance of seeking a family history of bleeding disorders before surgery in the neonatal period, particularly if the parents are consanguineous.