Cutaneous lesions in swine after decompression: histopathology and ultrastructure

A detailed histopathologic description of skin lesions from a porcine model of decompression sickness (DCS) is presented. Pigs were dived in a dry chamber on a variety of profiles over an 11-mo period, with a 0.1-0.6 (10-60%) incidence of cutaneous lesions. The clinical appearance of the lesions evolved from irregular, sharply demarcated areas of erythema to violaceous and, eventually, darkly mottled macules. The lesions were biopsied under deep, sedative anesthesia. Histologic abnormalities were found in 91% (20/22) of the biopsies from clinically apparent cutaneous lesions. Vascular congestion was the most common finding. Focal areas of vasculitis were noted in 45% (10/22) of the lesions. Perivascular neutrophil infiltrates, edema, and occasionally, hemorrhage were also noted. Ultrastructural abnormalities were found in all of the lesions studied. Acute inflammation affecting the dermal vasculature was the most common finding. Platelets were rarely observed aggregating within vessels. The clinical and histologic features of cutaneous lesions in pigs after decompression are compared with previous accounts in humans. The model provides a useful tool for the study of cutaneous lesions in DCS and may be a means of exploring interventions in the disease.