054 HBO Mediates Increased Nitric Oxide Production Associated with Wound Healing

Abstract

Hyperbaric oxygen (HBO) is used adjunctively to treat chronic, non‐healing wounds. Increased nitric oxide (NO) production during HBO is suggested as an important mechanism that promotes enhanced wound healing. The purpose of this study is the documentation of NO production during and following HBO treatments (txs). Diabetic and non‐diabetic patients receiving HBO therapy (20 txs; 2.0ATA × 90 min) provided wound fluid and fasting plasma and urine specimens for nitrate (NOx) determinations. Nitrate measurements were obtained prior to HBO (baseline), after 10 and 20 txs, and at one and four weeks following HBO completion. In patients healing after HBO baseline plasma NOx ranged between 17.7 and 33.20 μM. At 10 txs plasma NOx increased >50% to between 35.8–43.5 μM. At 20 txs plasma NOx decreased to between 22.3–35.5 μM. Healing diabetic patient plasma NOx increased after HBO reaching 170% of baseline at one month (57.8 ± 0.15 μM). Plasma NOx of healing non‐diabetic patients decreased to baseline levels at one month after HBO. Urine NOx values mirrored those of plasma NOx; wound fluid NOx elevations were delayed compared to plasma and urine. Conversely, non‐healing HBO patients did not demonstrate the early, significant elevations of plasma NOx after 10 txs. This study documents, for the first time, an early (10 txs), significant elevation of plasma and urine NOx after HBO that is associated with successful healing in diabetic and non‐diabetic patients. A similar early increase in plasma and urine NOx was not observed in patients not responding to HBO therapy. These findings suggest that HBO‐mediated increased NO production plays a critical role in the correction of impaired wound healing in selected patients. Furthermore, early plasma and urine NOx determinations after HBO therapy may prove valuable in the prediction of the clinical outcome of treatment.