J Cerebrovasc Endovasc Neurosurg > Volume 19(1); 2017 > Article
Moon: Spontaneous Absorption of Cerebral Air Emboli

TO THE EDITOR

I read with interest the recent report by Dr. Yang describing two cases of cerebral arterial air embolism (AGE) occurring during cerebral angiography in which the emboli appeared to be spontaneously absorbed into the bloodstream.11) Indeed there are at least two mechanisms for air bubbles within blood to resolve spontaneously, as evidenced by case series of arterial gas embolism without detectable gas on brain imaging.2) Gases within a bubble will diffuse into the surrounding medium at a rate depending on their partial pressure gradients. If the patient is breathing air the partial pressure gradient for nitrogen is fairly small. However it increases significantly if the patient is breathing supplemental oxygen, causing bubbles in blood and tissues to resolve more quickly.3)7)8)9)
Another explanation for the bubble disappearance is distal progression and passage via the capillaries into the cerebral veins. In anesthetized rabbits it has been shown that arterial air bubbles often do not remain trapped in the arterial circulation, but rather progress distally and can be recovered on the venous side.4)5)6) Despite their lack of persistence, the presence of cerebral arterial bubbles causes a progressive decrease in regional cerebral blood flow that can persist for several hours.4)5)6)
As Dr. Yang and colleagues point out, hyperbaric oxygen (HBO2) does result in rapid resolution of intravascular bubbles. However it has other pharmacological properties that are beneficial in AGE. HBO2 tends to inhibit the endothelial binding of leukocytes that occurs after tissue ischemia, and thus reduces mechanical obstruction in the microvasculature caused by adherent leukocytes.1)12) This is supported by clinical observations, showing improvement that occurs after HBO2 treatment of AGE even in the absence of radiographically visible bubbles.2)10)
In summary, spontaneous resolution of cerebral AGE reported by Dr. Yang is supported by other clinical observations. However, in managing these patients it is important to realize that AGE can initiate secondary phenomena such as regional hypoperfusion, which can sustain neurological injury. HBO2 not only can facilitate bubble resolution but also ameliorate some of these secondary phenomena and facilitate clinical improvement even when bubbles have resolved. It is therefore important not to withhold HBO2 merely on the basis of the absence of bubbles.

References

1. Atochin DN, Fisher D, Demchenko IT, Thom SR. Neutrophil sequestration and the effect of hyperbaric oxygen in a rat model of temporary middle cerebral artery occlusion. Undersea Hyperb Med. 2000 Winter;27(4):185-190;
pmid
2. Benson J, Adkinson C, Collier R. Hyperbaric oxygen therapy of iatrogenic cerebral arterial gas embolism. Undersea Hyperb Med. 2003 Summer;30(2):117-126;
pmid
3. Butler BD, Luehr S, Katz J. Venous gas embolism: time course of residual pulmonary intravascular bubbles. Undersea Biomed Res. 1989 1;16(1):21-29;
pmid
4. Gorman DF, Browning DM, Parsons DW, Traugott FM. Distribution of arterial gas emboli in the pial circulation. SPUMS J. 1987 17(3):101-115.
5. Helps SC, Meyer-Witting M, Rilley PL, Gorman DF. Increasing doses of intracarotid air and cerebral blood flow in rabbits. Stroke. 1990 9;21(9):1340-1345;
crossref pmid
6. Helps SC, Parsons DW, Reilly PL, Gorman DF. The effect of gas emboli on rabbit cerebral blood flow. Stroke. 1990 1;21(1):94-99;
crossref pmid
7. Hyldegaard O, Madsen J. Influence of heliox, oxygen, and N2O-O2 breathing on N2 bubbles in adipose tissue. Undersea Biomed Res. 1989 5;16(3):185-193;
pmid
8. Hyldegaard O, Madsen J. Effect of air, heliox, and oxygen breathing on air bubbles in aqueous tissues in the rat. Undersea Hyperb Med. 1994 12;21(4):413-424;
pmid
9. Hyldegaard O, Møller M, Madsen J. Effect of He-O2, O2, and N2O-O2 breathing on injected bubbles in spinal white matter. Undersea Biomed Res. 1991 Sep-Nov;18(5-6):361-371;
pmid
10. Tekle WG, Adkinson CD, Chaudhry SA, Jadhav V, Hassan AE, Rodriguez GJ, et al. Factors associated with favorable response to hyperbaric oxygen therapy among patients presenting with iatrogenic cerebral arterial gas embolism. Neurocrit Care. 2013 4;18(2):228-233;
crossref pmid pdf
11. Yang TK. Spontaneous absorption of cerebral air embolus developed accidentally during an intra-arterial procedure. J Cerebrovasc Endovasc Neurosurg. 2016 12;18(4):391-395;
crossref pmid pmc
12. Zamboni WA, Roth AC, Russell RC, Graham B, Suchy H, Kucan JO. Morphological analysis of the microcirculation during reperfusion of ischemic skeletal muscle and the effect of hyperbaric oxygen. Plast Reconstr Surg. 1993 5;91(6):1110-1123;
crossref pmid


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