Nj. Zemmel et al., A TEMPORAL ANALYSIS OF THE EFFECTS OF PRESSURIZED OXYGEN (HBO) ON THEPH OF AMPUTATED MUSCLE-TISSUE, Annals of plastic surgery, 40(6), 1998, pp. 624-629
The effect of hyperbaric oxygen (HBO) on ischemic muscle tissue pH was
evaluated continuously. The hind limbs of male Sprague-Dawley rats (N
= 11, both groups) were amputated and stored in room air (20.1% oxyge
n [O-2], 1.0 ATM, 24 degrees C) or in HBO (100% O-2, 2.9 ATM, 24 degre
es C) for 240 minutes. Rat muscle tissue pH was continuously monitored
with a micro-pH electrode following amputation. There was no signific
ant difference between the average starting tissue pH of control and t
reated limbs (p = 0.45). At 240 minutes of ischemia the control group
tissue pH decreased 0.80 pH units whereas the treatment group decrease
d 0.68 pH units (p < 0.05). The tissue pH of control limbs declined 30
.7 times faster than treated limbs during the first 36 minutes of isch
emia (p < 0.05). From 36 to 240 minutes the rates of acidosis were sim
ilar and did not differ significantly (p = 0.46). In a separate study,
male Sprague-Dawley rats were anesthetized with pentobarbital and ket
amine. Aortic arterial blood gases were obtained at 5 minutes (N = 8)
and 15 minutes (N = 8) postanesthesia. The average serum pH, carbon di
oxide, oxygen, and bicarbonate levels remained within normal limits in
both groups and did not differ significantly (p > 0.05 for all parame
ters). Anesthesia produced no serum respiratory or metabolic acidosis
and did not contribute to the initial ischemic tissue pH. These result
s suggest that HBO delays the progression of metabolic acidosis in thi
s amputated limb model. This is further supporting evidence for the ti
ssue-preserving effect of oxygen when delivered in hyperbaric conditio
ns. However, the clinical application of this technique may be limited
due to the difference in the volume of tissue presented for major lim
b replantation and the short window of beneficial effects.