When a preliminary analysis suggested that treatment with HBO might cause an increased mortality due to HBO, a paired control study of 36 patients treated with HBO and 36 matched controls was carried out. While mortality, mean day of death, and total hospital days were the same between the two groups, the HBO group suffered more kidney damage, had more positive blood cultures. The paired control method showed that the increased mortality observed in both groups of patients studied was not due to HBO treatment but to some other undetected selection factor. The findings that the HBO-treated patients had increased sepsis and renal damage warrants further investigation.

Waisbren, Schutz, Collentine, Banaszak, Stern, , , , (1982). Hyperbaric oxygen in severe burns. Burns, including thermal injury, 1982 Jan;8(3):176-9. https://www.ncbi.nlm.nih.gov/pubmed/7059858