I think, trend can continue even with volume divergence (as mentioned by raunak) .. but that might be only for shorter term. Long term trends, sustainable trend needs all 3 pillers of TA suplementing each other - and these piller are Price, Time and Volume.
Any divergence is a warning sign and needs to be further investigated.
Litrature is full of gyan on price analysis.. but unfortunately, there is very limited gyan on other 2 pillers hence people find it difficult to implement it.
If you read the concepts of VSA - volume spread analysis, you get very different insight into high volume /low volume activities.
In my view, high volume is important signal to watch near key levels before tagging them with bullish/bearish. And low volume is acceptable once trend is in place.
Presence of low volume, narrow range etc on key zone is clearly warning sign for me.
And most of the time, trading decision is to WAIT and LET MARKET OPEN FEW MORE CARDS.
Happy Trading.