diff --git a/jupyter_console/ptshell.py b/jupyter_console/ptshell.py
index 4943dab..0f9e4f3 100644
--- a/jupyter_console/ptshell.py
+++ b/jupyter_console/ptshell.py
@@ -839,7 +839,7 @@ def include_output(self, msg):
     async def handle_external_iopub(self, loop=None):
         while self.keep_running:
             # we need to check for keep_running from time to time
-            poll_result = await self.client.iopub_channel.socket.poll(500)
+            poll_result = run_sync(self.client.iopub_channel.socket.poll)(500)
             if poll_result:
                 self.handle_iopub()