[Euthanasia, catastrophic disease and the moribund patient].

Euthanasia has always constituted a controversial subject, but has recently been revived by a good number of well meaning intellectuals, many of whom, by and large, are not physicians. The present resurgence of this matter is due, primarily, to the prevalence of modern medical technology that makes it possible to maintain a futile life, often vegetative in nature, for an extended and even indefinite period of time. This is a complex situation that must be focused from different angles, one of which can be attributed to the conflict often experienced by physicians who have to deal with the management of catastrophic illness and realize how impotent they may be to achieve such difficult task.

Effect of allopurinol on the survival of experimental pig flaps.

Allopurinol has been reported to improve cell survival in a variety of conditions, including the ischemia-reperfusion injury occurring in skin flaps. It has been suggested that the beneficial effect of allopurinol on rat skin flaps is through blockage of xanthine oxidase-generated oxygen-derived free radicals. We have previously reported on the lack of xanthine oxidase activity in the skin of humans and pigs as compared with that of rats.

Cyclophosphamide-induced neutropenia: effect on postischemic skin-flap survival.

In a blinded study, 24 pigs were randomized to a 5-day preoperative treatment regimen of cyclophosphamide (n = 12) or placebo (n = 12). At operation, buttock cutaneous and latissimus dorsi myocutaneous flaps were created and then subjected to 6 hours of global ischemia. After 24 hours of reperfusion, flap skin and muscle survivals were determined.

Pathophysiology of ischemic skin flaps: differences in xanthine oxidase levels among rats, pigs, and humans.

Oxygen-derived free radicals have been implicated in a variety of diseases and pathologic processes, including ischemia reperfusion injury (IRI). Based on experimental work with rat skin-flap models, the enzyme xanthine oxidase (XO) has been proposed as a major source of free radicals responsible for tissue injury and flap necrosis. The presence of this enzyme is variable within different tissues of a specific species and between species.

Critical ischemia times and survival patterns of experimental pig flaps.

Previous work on critical ischemia time suggested (1) a greater susceptibility of myocutaneous flaps over skin flaps to the ischemia reperfusion injury and (2) that duration of ischemia may affect the survival area of a flap. Using a pig model, 55 animals were operated on and the critical ischemia times and survival patterns of the buttock skin (n = 85) and latissimus dorsi myocutaneous (n = 88) island flaps were determined after being submitted to 0, 2, 4, 6, 8, 10, 12, 14, and 16 hours of normothermic ischemia. The average critical ischemia times (CIT50) were determined to be 9 and 10 hours for the buttock skin and latissimus dorsi myocutaneous flaps, respectively.