Please read my comments in red above.
My advise to you (I have already done this, so speaking from experience and it is the same advise I got from immigration lawyer), do your medicals with the current passports. As soon as your DMP confirms your results have been sent to CIC, immediately go and have your passports renewed with urgent fees. The expiry date of visa will be linked to the passport you send once you get your passport request, not the one you do your medicals with. If still not convinced, think of it this way, people get passport requests almost a year after the medicals, CIC does not expect applicants to have their passports valid for that long.
The real problem you may have, which you are not considering is transferring your iqma to the new passport. Your company may not be happy with the costs associated with this.
Regards,
Thanks for the detailed reply,
But i still have one question, As u mentioned that i should send my new passport OR should i attach my old passport with that new one?
Since there is instruction to attach the old passport for at least 2 years with the new one..