Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Photograph of the 6.4‐French (2.1‐mm) esophageal multi‐use pH/impedance catheter showing impedance channels (arrow heads), each 2 cm in length in between the impedance sensors, each in the form of a 4‐mm cylindrical ring, and one pH sensor (arrow heads and arrow). The catheter is attached to the recording device (ZepHr) from which data are uploaded onto a computer using proprietary software.
