How would you know if you inserted a CANNULA and hit a valve?

If you insert a cannula and hit a valve, you may notice a sudden resistance while advancing the cannula, and you might feel a "pop" sensation. Additionally, you may observe a change in blood flow or the presence of blood in the cannula, indicating that the cannula has penetrated the valve. In some cases, the cannula may also fail to advance further, suggesting that it is obstructed by the valve.