Brass Push-In Tube Fitting, 0.38 Tube OD to 1/4-18 Male NPT Swivel, 90 deg Elbow

Polyurethane tubing at 0.38 inch OD is exactly what this fitting is built for. Push the tube in and the internal gripping teeth lock onto it, then the O-ring seals against the tube's outer diameter. The 90-degree elbow handles that direction change without any bending or kinking the line. Just make sure your polyurethane tubing is 90 durometer or harder, since softer material won't hold in the grip teeth the way it needs to.