I scoured the web for sites and forums that might put me in touch with real live surgeons in an attempt to answer this question. I don't know that I succeeded too well in that, but then again, I don't know how many surgeons would spend their valuable time in a forum open to the general public, so when those efforts dried up rather quickly, I did not attempt to pursue fresher vines of knowledge. Instead, I'll leave you with some comments I was able to collect over on Quora (which is my first go-to site when I have a question that isn't fitting in neatly with the categories here at StackExchange). For those of you who haven't heard, Quora has both an English version and a Spanish one. I posted my question on both and these are some of the answers:
"Once more unto the breach, dear friends, once more."
"Let's do this!"
Well, let's just say that I have nothing yet to add here. The one response just isn't specific enough to add here and the other, well, the other is a question with a twist of humor. If you'd like to see the English answers in full context, visit this link:
Is there a special word or phrase surgeons say (officially or habitually) before operating on a patient?
For the Spanish, visit this one:
¿Hay una palabra o frase específica que dicen (oficialmente o habitualmente) los cirujanos en países donde se habla español antes de operar a un paciente?
Because I feel as if my attempt to research this falls just a little bit short and isn't quite as informative as it could be, I wanted to also leave you with something else I came across in the process. It is a chart from the World Health Organization. More specifically, it is a surgery checklist written in several different languages to include English and Spanish. I don't know how useful these images are to you, but I include them with the hope that you find them interesting.
I think what I may have been thinking about when I first saw the phrase “¡Al ataque!” were the types of scenes you see in the following clips:
The clip below made me wonder if it might have influenced the author to some degree:
Though it is a bit of a stretch to think that the author might have been influenced by the scene above, The Lorax did do very well at the box office and it was dubbed into Spanish. But I don't know when the book was published, so I can’t say which came first — the book I’ve referred to in this post or El Lórax. More likely, however, and as Diego has mentioned, “¡Al ataque!” is just a good way to generate enthusiasm for an operation, especially a tickling operation. Though Diego’s other suggestions for what a surgeon might say work just as well in my opinion, I don’t think any of them quite generate a sentiment of “comenzar con brio” quite like “¡Al ataque!” does.
As for confusing the use of a defibrillator with a surgical operation, I suppose that’s a reasonable thing for a person without a medical background to do. And perhaps it may be why “¡Al ataque!” didn’t seem entirely out of place to me initially. After all, when you take two paddles and deliver an electric shock with them to a person’s chest, I guess you could call that an attack ... an attack to the heart! Seriously though, protocol in such situations doesn’t advise shouting out “Attack!” Instead, you want to clear the area for all the appropriate reasons, but mainly because you want everyone but the victim to stand clear of the electricity and because touching the victim is potentially fatal. According to one source, you are to say:
I'm Clear, you're clear, we're all clear" while ensuring that the operator is not touching the victim or standing in a wet environment next to the victim that could conduct electricity through the rescuer.
— From First Aid/Automated External Defibrillation (AED)
Though this Wikibook has been translated into Spanish, it isn’t a word for word translation, and no mention is made of what should be said to other first responders or bystanders, but I would imagine it is some form of “¡Claro!” and not “Al ataque!”
As an educational sidenote, if you should ever need a defibrillator, and you’re in a Spanish-speaking country, you want to look for a DESA which is the Spanish equivalent of an AED and stands for desfibrilador externo semiautomático. If signs for it don’t have that acronym on them, they might look like this:
You might want to get some training before you ever have to use one, though.