Teach me to hear mermaids singing

Individual quality of life in patients with leukaemia and lymphoma

With increasingly sophisticated chemotherapy regimes being prescribed the quality of life of cancer patients has become a key outcome measure. Little has been reported concerning the experience of patients with haematological malignancy receiving chemotherapy. The objective of this study was to evaluate the clinical usefulness of a novel quality of life measure-the Schedule for the Evaluation of Individual Quality of Life-Direct Weighting (SEIQoL-DW) in a sample of patients with either leukaemia or lymphoma. Fifty-one patients from the haematology clinic and in-patient unit at The Royal Devon and Exeter Hospital completed the SEIQoL-DW; in addition, each patient completed the Hospital Anxiety and Depression Scale (HADS) and a ten item questionnaire covering aspects of their treatment and satisfaction with information provided. The practical application of the SEIQoL-DW is described and two patients quality of life profiles are illustrated for comparison. The relationship between quality of life, satisfaction with information provided and psychological distress as measured by the HADS is discussed.

Haemoglobin-based oxygen carriers

Haemoglobin-based oxygen carriers are being developed for use in blood replacement therapies, either for perioperative haemodilution or for resuscitation from haemorrhagic blood loss. There is a high demand for these products because of risks associated with blood transfusions and pending worldwide blood shortages. Development of these products has required new technologies in protein engineering; since the haemoglobin is cell-free in solution, the molecule must be modified to be retained within blood circulation. Three classes of haemoglobin are under development: intramolecular cross-linked, intermolecular polymerised and surface conjugated with polyethylene glycol. Two products based on cross-linking chemistry have been discontinued because of serious adverse events and/or increased mortality rate in Phase III clinical trials. Three products based on polymerisation chemistry are in ongoing Phase III clinical trials. A new product based on surface conjugation is in preclinical evaluation. Although cross-linked and polymerised products have shown to be safe in preclinical and early Phase I/II clinical trials, they have had difficulty in proving efficacy. The primary adverse effect for the majority of cross-linked or polymerised products is a haemodynamic response, leading to increased vascular resistance to blood flow. The physiological mechanisms are still incompletely understood, so that safety and efficacy cannot be completely dissociated. New understandings on the mode of action of these products will help to define their utility and application. New products are under development, designed specifically to maximise blood flow and tissue perfusion and therefore, oxygenation.

Blood substitutes

Red cell substitutes are a group of oxygen carriers designed to temporarily replace transfused blood. Each product is unique in its limitations and advantages. Research and development has been slow because of the far-reaching consequences of replacing an oxygen carrier outside of the red cell. Nevertheless, a number of products are in advanced clinical trials and nearing the market. When they are available for use it is likely that development will accelerate and even better products will substantially alleviate the world-wide shortage of blood for transfusion and enable the delivery of medical care to underserved populations. An important consequence of the development of these products has been a better understanding of how oxygen is delivered to tissues.

New transfusion strategies: red cell substitutes

Red cell substitutes are solutions that can potentially be used in emergencies or during surgery when rapid expansion of the blood volume with an oxygen carrier is needed. The three main types of products in development are based on cell-free hemoglobin, perfluorocarbon emulsions, or liposome-encapsulated hemoglobin. None is currently approved for clinical use, but several are in advanced clinical trials. Outside the red blood cell, hemoglobin is subject to degradation and heme loss. It readily diffuses in the plasma space and effectively scavenges nitric oxide. These properties must be understood and controlled if hemoglobin-based products are to fulfill their promise. The development of red cell substitutes affords us a deeper insight into how oxygen is delivered to tissues in the microcirculation and how blood-flow distribution is regulated within and between organs. As red cell substitutes become available to clinicians and scientists, clinical applications are expected to expand.