Q: Use of esophageal thermal probe is not contraindicated in a ventilated patient but which one concern should be kept in mind regarding use of esophageal thermal probe in ventilated patient?


Answer: Cooling by ventilated air if probe is not at right position.

The esophagus is close to the trachea and bronchii at the upper border of the inferior mediastinum, so if esophageal thermal probe is sitting in this region it may lead to cooling of this region especially during high ventilation rates. Thus, it is possible that in this region, the measured temperature may not necessarily be indicative of the myocardial or blood temperature. The esophagus is closest to the myocardium at approximately T8.  Therefore, level of T8/T9 retains its advantage as a site distal to the tracheal bifurcation and close to the left ventricle and aorta, and best suited for thermal monitoring.



References:

1. CAPUTA, M. Thermal gradients in the oesophagus of man during exercise and passive warming. J. Therm. Biol. 5: 249-251, 1980.

2. LINNARSSON, D., T. RIBBE, AND B. HALLEN. Oesophageal probe for heart and temperature monitoring during anaesthesia. Med. Biol. Eng. Comput. 20: 390-392, 1982.