[A device for monitoring respiration during anesthesia: the para-tracheal monitor].

The paratracheal audible respiratory monitor (PTARM) was assessed in anaesthetized patients who were not intubated. Its working principle is simple: the sound generated by the passage of air between the vocal cords is picked up by a microphone placed on the patient's neck; the electronic signal is then amplified and changed into an audible one. It can also be recorded. This monitor was compared to others already available, Transcor, which monitors breathing sounds using a stethoscope as transducer, and Thermistor, which monitors the changes in air temperature due to air movement during breathing. The PTARM does not tie the anaesthetist down to the patient's bed, as do the precordial or oesophageal stethoscopes. Its usefulness in detecting aspiration is under investigation. It is a reliable, noninvasive and cheap breath-to-breath respiratory monitor, which can also be used in intubated patients.