To the Editor:
We read with interest the recent article by Singh et al.1 We place many brachial artery catheters in our practice and find them useful.
It would be interesting to know whether ultrasound guidance was used for some or all of the brachial artery arterial catheterizations reported by Singh et al.1 Ultrasound guidance has been shown to reduce the complications from femoral artery access performed for cardiology and vascular surgery interventions.2,3 The same might be true for brachial catheterization.
It would also be interesting to know what infection-prevention measures were taken by Singh et al.1 in the context of the infection rate (0.04%) they report. The Centers for Disease Control and Prevention recommends that the infection-prevention measures taken for arterial catheterization should be similar to those for central venous catheters,4 although anecdotally it appears that in many anesthesia practice settings, arterial catheterization is performed without all of the recommended precautions.
Despite documenting a relatively low rate of vascular complications of brachial artery catheters, Singh et al.1 state, “…forearm and hand perfusion via collaterals usually is insufficient if acute occlusion of the brachial artery occurs.” There is a common notion that the brachial artery lacks effective collaterals, but is it correct? Wong et al.5 reviewed the angiographic anatomy and concluded that “routes of collateral flow enable the distal extremity to be perfused even in the face of brachial artery laceration, thrombosis, or external compression.”
Anecdotal reports tend to support the conclusion of Wong et al.5 Schanzer et al.6 reported a series of 21 patients in whom the brachial artery was deliberately ligated in the treatment of infected arteriovenous dialysis grafts. No patients suffered ischemic complications. Wolfswinkel et al.7 reported a case of a 6-yr-old child with a supracondylar humeral fracture that resulted in complete brachial artery transection. The patient’s hand remained pink and well perfused, and angiograms shown in this report demonstrated the collateral circulation around the transected artery. There are other reports of supracondylar humerus fractures with interruption of the brachial artery, suggesting that the collateral circulation may be adequate to prevent hand ischemia.8
If there is adequate collateral circulation to prevent ischemia with brachial occlusion, what is the mechanism of ischemic complications after brachial artery catheterization, as affected 33 of 21,597 of the patients (0.15%) reported by Singh et al.1 ? It is important to distinguish between embolic and purely local thrombotic events at the catheter site. This is because embolic events may result in impaired flow in multiple vessels and may impair collateral vessel flow as well as flow in the index vessel, whether radial or brachial. In the setting of emboli, the arterial catheter may be a contributing factor in producing ischemia or may simply be an innocent bystander.
Embolic events may be difficult to recognize. The near simultaneous appearance of ischemia in multiple vascular beds is suggestive that embolization has occurred. For example, Lee et al.9 reported a case of simultaneous embolic occlusion of brachial and cerebral arteries, resulting in a stroke and limb ischemia (there was no brachial artery catheter in this case).
It is impossible to know how many of the cases of ischemia in the report by Singh et al.1 were due to embolic events; however, given that many of the patients were very sick, it seems likely that many were embolic. Patients with brachial artery complications had prolonged hospital stays, greater in-hospital mortality, and a “much greater incidence of severe life-threatening postoperative complications, including cardiac arrest, kidney injury requiring dialysis, multiorgan failure, and use of extracorporeal membrane oxygenation for severe cardiac or pulmonary failure.”1
The authors declare no competing interests.