Hyperbaric Oxygen and Outcome After Below Knee Amputations

This study is being conducted to assess the utility of hyperbaric oxygen as an adjunctive treatment to reduce postoperative complications. It is hypothesized that HBO2 given in the immediate postoperative period will reduce postoperative complications in patients undergoing below-the-knee amputations. The objective of this study will be to compare treatment and standard care groups, randomly created of eligible patients, to compare their postoperative complications and to assess their postoperative hospital length of stay, 90-day mortality, failure to heal at 4 and 8 week follow-up visits and ability to ambulate with a prosthesis at 6 months post amputation.

This is a clinical study to test the hypothesis that Hyperbaric Oxygen (HBO2) given in the immediate postoperative period for a total of 10 treatments after Below-the-Knee Amputation (BKA) for vascular disease will reduce postoperative complications. Patients scheduled for BKA at Duke University Medical Center will be reviewed for contraindications to HBO2. Patients for whom HBO2 is not contraindicated may choose to be enrolled in the study. Patients enrolled will be randomly assigned to receive treatment or standard postoperative care. Each patient receiving treatment will receive twice daily HBO2 for 2 hours at 2 ATA. Patients receiving HBO2 will breathe 100% oxygen via head tent while inside a hyperbaric chamber at Duke University Hospital. The statistical plan for this study will test non-directional hypotheses (two-sided tests). Bonferroni correction will be used to adjust for multiple tests. The main analysis of the primary efficacy hypotheses will include data from all randomized patients in the group to which random assignment is made. Hence, the analysis will be intention to treat. This study will primarily aim to assess whether patients receiving treatment suffer fewer complications, as defined by the Vascular Quality Initiative, vs. patients who receive standard care. The Vascular Quality Initiative (VQI) is a multicenter voluntary reporting system for outcomes related to vascular surgery. The primary outcome of this study, postoperative complications, will be those outcomes meeting the definition set out in the VQI data dictionary, the set of definitions for inclusion in the VQI database. This allows for a standard definition of complications recognized by a majority of US academic medical centers. Secondary outcomes include hospital length of stay, 90-day mortality, failure to heal at 4 and 8 week follow-up visits and ability to ambulate with a prosthesis at 6 months post amputation.

Eligibility Criteria:
Inclusion Criteria:

* Able to consent
* Non-traumatic indication for lower limb amputation
* Able to receive hyperbaric oxygen therapy

Exclusion Criteria:

* Unable to consent
* Contraindication to hyperbaric oxygen
* End stage renal disease on dialysis
* Current renal failure as measured by creatinine levels vs baseline change of more than 1 mg/dL and for whom dialysis is expected to be required with the next month
* Calciphylaxis
* Traumatic injuries that are the cause of the amputation
* Cancer being treated by chemotherapy, scheduled to be treated, or being treated or scheduled to be treated by radiation.
* Limb amputation secondary to ischemic complications from other operations
* Second amputation or reoperation on prior amputation
* Pregnancy