Accession Number:

ADA629444

Title:

The Effect of a Hypobaric, Hypoxic Environment on Acute Skeletal Muscle Edema After Ischemia-Reperfusion Injury in Rats

Descriptive Note:

Journal article

Corporate Author:

ARMY INST OF SURGICAL RESEARCH FORT SAM HOUSTON TX

Report Date:

2010-05-15

Pagination or Media Count:

8.0

Abstract:

Background. Clinicians have postulated that decreased atmospheric pressure during air evacuation exacerbates muscle edema and necrosis in injured limbs. The present study investigated whether the mild hypobaric, hypoxic conditions of simulated flight during muscle reperfusion worsened muscle edema and muscle injury in an established animal model. Methods. Twenty male Sprague-Dawley rats under- went tourniquet-induced hind limb ischemia for 2 h. After removal of the tourniquet, rats were divided into two groups n 10group, and exposed to either 1 hypobaric, hypoxic conditions HB of 522 mm Hg simulating 10,000 feet, the upper limit of normal aircraft cabin pressure, or 2 normobaric, normoxic conditions NB of 760 mm Hg sea level, for 6 h. Muscle wet weight, muscle drywet weight ratios, viability, and routine histology were measured on the gastrocnemius and tibialis anterior muscles. Blood samples were analyzed for percentage hematocrit, leukocyte count, and coagulation status. Results. Ischemia resulted in significant edema in both groups P less than 0.05. Normobaric normoxia caused greater edema in the gastrocnemius compared with hypobaric hypoxia the tibialis anterior was not significantly different between groups. The decrease in body weight for NB and HB was 3.4 or - 1.4 and 10.7 or - 1.2 g, respectively P less than 0.05. Hematocrit was 44.7 or - 0.5 and 42.6 or - 0.6 P less than 0.05. Conclusions. The hypobaric, hypoxic conditions of simulated medical air evacuation were not associated with increased muscle edema following 2 h of ischemic injury. This suggests that the other factors, such as resuscitation, may be the cause of muscle edema in flight-evacuated patients.

Subject Categories:

  • Medicine and Medical Research
  • Stress Physiology
  • Medical Facilities, Equipment and Supplies
  • Weapons Effects (Biological)
  • Escape, Rescue and Survival

Distribution Statement:

APPROVED FOR PUBLIC RELEASE