Hyperbaric Oxygen Therapy Can Help Patients Recover From Stroke

Hyperbaric Oxygen Therapy Can Help Patients Recover From Stroke

Introduction

In most developed countries, cerebrovascular disease is always ranked in the top ten causes of death. In United States, about 70% of hospitalized acute stroke patients have ischemic stroke. Although the mortality rate of acute ischemic stroke is less than that of hemorrhagic stroke, it still results in patient disabilities and complications that often lead to significant costs to individuals, families, and society. Traditional treatment for acute ischemic stroke includes thrombolytic therapy by injecting t-PA within three hours after onset of symptoms, and anti-platelet and/or anti-coagulant agents administered within the first 48 hours. Clinically, the narrow time window of thrombolytic therapy and co-existing contraindications limit the use of t-PA. Thus, searching for an effective supplemental treatment for acute ischemic stroke is imperative.

Hyperbaric oxygen therapy (HBOT) is valuable in treating acute CO poisoning, and air or gas embolism and in facilitating wound healing. Known mechanisms of HBOT-induced neuro-protection include enhancing neuronal viability via increased tissue oxygen delivery to the area of diminished blood flow, reducing brain edema, and improving metabolism after ischemia. Despite beneficial results in several animal models, the effectiveness in human ischemic stroke is still controversial. In a randomized, prospective, double-blind, sham-controlled pilot study published in 2003, Rusyniak et al. delivered HBOT to 33 patients with acute ischemic stroke who did not receive thrombolytic therapy, and assessed the therapeutic effectiveness after 24 hours and 90 days. They concluded that HBOT did not appear to be beneficial and might even be harmful for patients with acute ischemic stroke.

However, the viewpoint and shortcomings of this trial were challenged by others who suggested that further studies were needed to determine the feasibility of lower pressures, greater numbers of dives with better clinical outcomes, and suitable stroke sub-type. In 2006, Bennett et al. included three randomized controlled trials (106 participants) to assess the benefits and safety of adjunctive HBOT in the treatment of acute ischemic stroke. Their systematic review did not demonstrate that HBOT could improve clinical outcomes. However, due to the lack of guidelines for study design, the use of HBOT in stroke patients could not be justified. Moreover, a previous report showed repetitive (10 dives) HBOT with lower pressure (2.0 ATA) and short duration (60 min) for a 56 year-old American patient suffering from acute ischemic stroke on the left corona radiata leading to right hemiparesis and dysarthria, had great improvement. This study prospectively assessed the efficacy and feasibility of applying 10 repetitions of HBOT at 2.0 ATA for one hour in patients with mild acute ischemic stroke within 3-5 days after stroke onset to reinvestigate the role of HBOT in treating acute ischemic stroke.

The largest body of evidence involving the use of hyperbaric oxygen for neurologic illness is found in the field of cerebral ischemia, which was reviewed by Helms et al. in 2005. At the center of an infarcì, blood flow is completely absent, causing neurons to die within ...