Processing an evacuated blood sample collection tube or other vessel by plasma enhanced chemical vapor deposition to apply a tie coating or layer (289), a barrier coating or layer (288), and optionally one or more additional coatings or layers. The tie coating or layer of SiOxCy is applied under partial vacuum and, while maintaining the partial vacuum unbroken in the lumen, the barrier coating or layer is applied. Then optionally, while maintaining the partial vacuum unbroken in the lumen, a pH protective coating or layer of SiOxCy can be applied. As a result of this processing, a coated vessel is produced having a lower gas permeation rate constant into the lumen than a corresponding vessel made by the same process except breaking the partial vacuum in the lumen between applying the tie coating or layer and applying the barrier coating or layer. Retention features are also described for keeping the vessels stoppered during exposure to reduced ambient pressure.
