Exploring the boundaries of perfusion. Left field: square tubes and current changes!

Basic principles and concepts from engineering and the physical sciences may help improve our practice in the field of perfusion. This paper explores how these analogies and concepts may help us optimize and individualize target blood pressure on bypass, cardiopulmonary bypass prime constitution, flows during cardiopulmonary bypass in patients with renal failure, hemo-filtration on bypass, timing of cross clamp removal, de-airing, carbon dioxide management, and set up of the heart lung machine. Often an understanding of the factors involved in an engineering principle is sufficient, and a detailed mathematical comprehension is unnecessary. Appreciation of concepts from engineering and physical sciences may help to develop a patient directed perfusion practice as opposed to a one-size-fits-all practice.