1 We compared the effects of dopexamine, dopamine and dobutamine on the heart rate, blood pressure and renal blood flow of six healthy volunteers in an open triple crossover trial. 2 The results suggest that at the dose ranges investigated dopamine was the most effective agent for increasing renal blood flow.

Haemofiltration is a popular technique for removal of fluid and small to medium size molecules in critically ill patients. Whilst there is often good information on drug disposition in chronic renal failure, there is a lack of information available to guide Intensivists on how to prescribe drugs in patients in acute renal failure undergoing haemofiltration or haemodiafiltration.

Background: Transferring the theoretical aspect of continuous renal replacement therapy to the bedside and delivering a given ''dose'' can be difficult. In research, the ''dose'' of renal replacement therapy is given as effluent flow rate in ml kg À1 h À1 . Unfortunately, most machines require other information when they are initiating therapy, including blood flow rate, pre-blood pump flow rate, dialysate flow rate, etc. This can lead to confusion, resulting in patients receiving inappropriate doses of renal replacement therapy. Our aim was to design an excel calculator which would personalise patient's treatment, deliver an effective, evidence-based dose of renal replacement therapy without large variations in practice and prolong filter life. Our calculator prescribes a haemodialfiltration dose of 25 ml kg À1 h À1 whilst limiting the filtration fraction to 15%. Methods: We compared the episodes of renal replacement therapy received by a historical group of patients, by retrieving their data stored on the haemofiltration machines, to a group where the calculator was used. In the second group, the data were gathered prospectively. Results: The median delivered dose reduced from 41.0 ml kg À1 h À1 to 26.8 ml kg À1 h À1 with reduced variability that was significantly closer to the aim of 25 ml kg À1.h À1 (p < 0.0001). The median treatment time increased from 8.5 h to 22.2 h (p ¼ 0.00001). Conclusion: Our calculator significantly reduces variation in prescriptions of continuous veno-venous haemodiafiltration and provides an evidence-based dose. It is easy to use and provides personal care for patients whilst optimizing continuous veno-venous haemodiafiltration delivery and treatment times.

Objective: To examine the extent of critical care activity, on each weekday, in 9 hospitals accepting acute medical and surgical patients.

We describe the case of a young male, found collapsed following poisoning with an unknown substance. He had a Glasgow Coma Score (GCS) of three with a profound metabolic acidosis, despite poisoning with a substance which was strongly basic. He was treated with haemodiafiltration to correct the biochemical derangements. The poison was found to be cyanide, so the patient was also given sodium thiosulphate as an antidote. We review the pathophysiology of cyanide toxicity, the antidotes available and discuss the role of haemodiafiltration in poisoning where the ingested substance is unknown.