‘Flexible’ or ‘lifestyle’ dialysis: Is this the way forward?

BACKGROUND: Despite the advent of two new dialysis options, nocturnal home haemodialysis and short daily haemodialysis, many units are yet to build them into the modalities on offer to end-stage renal failure patients. The reasons behind this inertia are complex but primarily include anxieties about workload, budgetary implications and outcome data. METHOD: The Geelong dialysis programme, where both nocturnal home haemodialysis and short daily haemodialysis are offered, is compared with Australian and New Zealand national profiles. RESULTS: Significant profile differences emerge when comparing sessions/week and h/week between the three groups. Most Australian (92.93%) and New Zealand (95.07%) haemodialysis patients dialyse for three sessions/week. This contrasts to Geelong where only 73.6% dialyse for three sessions/week. 18.8% of Geelong haemodialysis patients versus 1.8% (Australia) and 0.9% (New Zealand) dialyse for five or more sessions/week. Australia and New Zealand follow similar h/session patterns although more Australians (44.2%) dialyse for 4 h and fewer (24.2%) for 5 h than their New Zealand counterparts (39.6% and 29.8%, respectively), and few dialyse outside the 3.5-5 h window. In contrast, 6.7% of Geelong patients dialyse for 2-2.5 h/session versus Australia (0.9%) and New Zealand (0.2%). This represents the Geelong short daily dialysis programme. More Geelong patients (>15%) dialyse >/=8 h/week and represent the Geelong nocturnal home haemodialysis programme. CONCLUSION: The flexible Geelong programme has been supported without exceeding the budget applied to a conventional dialysis programme with the same patient numbers.     

Simultaneous pancreas–kidney transplantation: to anticoagulate or not? Is that a question?

Pancreas graft loss due to venous thrombosis is the leading non-immunological cause for graft failure following kidney-pancreas transplantation. Thromboelastography (TEG)-directed anticoagulation protocol has shown that approximately one-third of the patients undergoing pancreas transplantation require therapeutic anticoagulation to prevent the occurrence of graft thrombosis. This article presents the argument for individualised anticoagulation in these patients based on their TEG tracings and suggests the use of TEG in patients undergoing pancreas transplantation.     

The gastric cardia: to be or not to be?

The origin and biologic significance of cardiac gastric mucosa are controversial. Traditionally, it has been considered native mucosa and part of normal foregut development. It has been recently suggested that cardiac mucosa is present only as a metaplastic response to gastroesophageal reflux disease and therefore always abnormal. We evaluated the esophagogastric junction in 100 pediatric autopsy samples to determine the existence, characteristics, and length of pure cardiac mucosa at different ages. No patient had a history of gastroesophageal reflux disease. Cardiac mucosa immediately distal and contiguous to the esophageal squamous mucosa was identified in all 100 samples, varying in length from 0.1 to 3 mm; the mean length was 1 mm. There was an inverse correlation between patient age and length of cardiac mucosa; gender had no influence on measured length. Three patients had mild to moderate histologic esophagitis; two had gastritis. No metaplastic features or Helicobacter pylori were identified. These findings support the concept that there is a normal, variably narrow developmental zone at the esophagogastric junction covered by cardiac mucosa and is present at birth. When cardiac type mucosa is found in biopsy material, it does not necessarily represent evidence of a mucosal metaplastic response to gastroesophageal reflux disease.     

Vacuum-assisted venous drainage: to air or not to air, that is the question. Has the bubble burst?

Assisted venous drainage is a recent development in cardiopulmonary bypass (CPB) and was introduced to overcome limitations in achieving adequate blood flow through small diameter cannulas used in minimally invasive surgery. The more common application, vacuum assisted venous drainage (VAVD) is now widely used in both adult and pediatric CPB. During a clinical investigation into pharmacological cerebral protection at Green Lane Hospital, we repeatedly observed evidence of emboli in the right common carotid artery following both entrainment of air into the venous line, and also, reductions in the blood level of the hard-shell venous reservior. We subsequently embarked upon a series of in vitro experiments designed to identify sources of emboli from the CPB circuit, and to evaluate the ability of CPB circuit components to remove air entrained into the venous line under conditions of both gravity and vacuum assisted venous drainage. Initial experiments revealed design features of certain hard-shell venous reservoirs that generated gaseous emboli. In further studies using adult circuits, entrainment of air into the venous line under conditions of conventional gravity venous drainage resulted in emboli distal to the arterial filter. When these studies were repeated using VAVD, arterial line emboli increased eight to tenfold. Initial experiments with a pediatric circuit showed similar findings. Cerebral emboli during CPB have been positively correlated with increasing neurocognitive deficits. The application of VAVD has been employed clinically without any significant redesign of the components of the CPB circuit. While VAVD may be efficacious in certain scenarios, a thorough understanding of its influence on CPB is essential. Advantages must be balanced against potential hazards. The safe use of VAVD necessitates refinement of perfusion techniques, judicious choice of application, and further development of the CPB circuit.