We published one version of a protocol here: http://onlinelibrary.wiley.com/doi/10.1111/sms.12169/abstract;jsessionid=B84925AB9CB6181CE713E8708D20EC23.f01t03
I am not sure how commonly used this is. "Validated" will be a tricky one here as it will depend upon whether it is possible to validate against another method to determine VO2 max using another arm exercise protocol.
my suggestion is: just keep in mind the following main points, regardless of the standard protocol (that, as Stuart points out, it's not easy to consider "valid" comparing to another one).
1) do not accept the peak but look for the real VO2max, with a plateau after a 2' increase of the power
2) because of the previous point, any protocol with steps (even short as 2') can be misleading, and personally I prefer, especially for arm ergometry, a continuous "ramp" incremental protocol, starting from 10-20w (depending of the fitness level of the subject), reaching an increment of +5-10w (depending of the fitness level of the subject) every 30"
2) the total protocol duration should be much shorter than those for leg testing. 10 minutes is the top maximal duration, but 5-6 could be more than enough.
3) put a lot of attention to the setting of the trunk and the legs. Once you define the angles that can be obtained with your ergometer (hip and knee), mantain them for all the tests. The involvement of trunk and leg muscles could change a lot the VO2max values a subject can reach. I suggest straight knees and the largest possible thigh-trunk angle.
I would like to know if you have experience with arm-crank exercise tests in patients with vascular disease, such as Peripheral Artery Disease patients.
I would encourage you to take a look at the following chapter from some of my colleagues for generic guidelines on upper body exercise testing;
Smith, P. M. & Price, M. J. (2007) Upper-body exercise. In: E. M. Winter., A. M. Jones., R. C. R. Davison., P. D. Bromley. & T. H. Mercer. (eds). BASES Sport and Exercise Physiology Testing Guidelines. pp. 138 - 144.
Alternatively, the following papers (same authors) may be of interest. Much of their work has focused on protocol standardisation.
Smith, P. M., Doherty, M. & Price, M. J. (2007a) The effect of crank rate strategy on peak aerobic power and peak physiological responses during arm crank ergometry. Journal of Sports Sciences, 25, 711-718.
Smith, P. M., Doherty, M., Drake, D., & Price, M. J. (2004). The influence of step and ramp type protocols on the attainment of peak physiological responses during arm crank ergometry. International Journal of Sports Medicine, 25 (8), 616-621
Smith, P. M., Price, M. J., & Doherty, M. (2001). The influence of crank rate on peak oxygen consumption during arm crank ergometry. Journal of Sports Sciences, 19(12), 955-960.
In my experience, I would encourage the use of stepwise test with a couple of 'longer steady state' stages at the start; Feel free to see a recent paper of mine.
Hill, M.W., Goss-Sampson, M., Duncan, M.J., and Price, M.J. (2014). The effects of maximal and submaximal arm crank ergometry and cycle ergometry on postural sway. Eur J Sport Sci. 2014;14(8):782-90
You will unlikely see a VO2max per se as subjects will reach volitional exhaustion due to peripheral limiting factors rather than central, so unless trained you may not see a classic plateau....
While I don't have direct experience with PAD a lot of my work concentrates on clinical groups such as those with arterial disease....happy to respond if you can add a more 'detailed' question?
I am aware of plenty of the work in the area....just depend on what you are interested in.