Listen to the Pushbullet websocket stream of events, and hit a key on a particular event.

pushbullet listener

#!/usr/bin/env python2
import ConfigParser
import time
import json
import os
import requests
import subprocess
import websocket

def toggle_donotdisturb():
  script = 'tell application "System Events" to keystroke "D" using {command down, shift down}'
  subprocess.check_call(["osascript", "-e", script])

def on_error(ws, error):
  print error

def on_close(ws):
  print "closed"

def on_message(ws, message):
  message = json.loads(message)
  if message["type"] == "tickle" and message["subtype"] == "push":
    ten_minutes_ago = str(time.time() - 10 * 60 * 1000)
    URL = "https://api.pushbullet.com/v2/pushes?modified_after="
    data = json.loads(requests.get(URL + ten_minutes_ago, auth=(api_key, '')).content)
    if data["pushes"][0]["title"].strip().lower() in ("start pomodoro", "stop pomodoro"):
      toggle_donotdisturb()
    
if __name__ == "__main__":
  websocket.enableTrace(True)

  parser = ConfigParser.ConfigParser()
  parser.read(os.path.expanduser("~/.pushbullet"))
  api_key = parser.get("auth", "api-key")
    
  ws = websocket.WebSocketApp("wss://stream.pushbullet.com/websocket/" + api_key,
                              on_message=on_message,
                              on_error=on_error,
                              on_close=on_close)
    
  ws.run_forever()

On OSX, you can go to System Preferences -> Keyboard -> Shortcuts -> Mission Control and bind Command-Shift-D to do-not-disturb mode. Then this will toggle do not disturb on specific pushbullets.