Black rubber or clear plastic delivery tubing for nitrous oxide: patient preference

Entonox (a 50:50 mixture of nitrous oxide in oxygen) is given via black rubber corrugated tubing in most obstetric units even though this has been superseded by clear plastic tubing in many operating theatres. This trial has shown that more women in labour preferred using plastic rather than black rubber tubing because it was lighter in weight and devoid of the unpleasant smell associated with the latter. Women also suffered a greater degree of dizziness while using the black rubber tubing. Clear plastic tubing seems a sensible alternative for the delivery of Entonox now that the risks associated with the build up of static charge have little importance. It is cheap, odourless and lightweight, it can be cut to any length, fits standard 22 mm connections, is easy to clean and although durable is potentially disposable.