Best way to insert NG tube in intubated patients

A randomised controlled trial on 200 anaesthetised, tracheally intubated adults compared four methods of nasogastric tube placement, looking at success rates, time to insertion, and complications.
The four groups were: control, using a ureteral guidewire as stylet, a slit endotracheal tube as an introducer, and head flexion with lateral neck pressure. All intervention groups were more successful than the control group. The time necessary to insert the NG tube was significantly longer in the slit endotracheal tube group, which also had the highest bleeding rate. Complications were fewest in the flexion group.
Nasogastric tube insertion using different techniques in anesthetized patients: a prospective, randomized study
Anesth Analg. 2009 Sep;109(3):832-5