Don’t leave a question unanswered
The greatest contributor to communications lag in a distributed team is when a question is asked that goes unanswered for days at a time.
As a project manager working with distributed teams, strive to acknowledge you have received the question as quickly as you can, schedule time to answer it as soon as you can — you may need to have a local meeting or undertake research or due diligence — and once you have the information you need, reply to the original question.
The greatest tool you have to reducing communications lag in distributed teams is to never leave a question unanswered at the end of your work day.