Comparison of Nasopharyngeal Temperature Measured at Fossa of Rosenmuller and Blindly Inserted Temperature Probe with Esophageal Temperature: A Cross-Sectional Study

INTRODUCTION: Monitoring body temperature and maintaining normothermia are now essentially the standard-of-care during anesthesia. This study was designed to compare the temperature measured by nasopharyngeal temperature probes inserted by landmark method and fiberscope-guided method with esophageal temperature. We hypothesized that placing the temperature probe at the level of fossa of Rosenmuller will reflect core temperature as it is in close relationship to the brain. SUBJECTS AND METHODS: Sixty-five patients aged 18–60 years were enrolled in this cross-sectional study. Two methods were used in our study to place the temperature probes. In landmark-based method, we inserted temperature probe through nostril for a depth equal to philtrum-tragus distance. In fiberscope-guided method, the temperature probe was inserted into nostril and its tip was positioned at fossa of Rosenmuller under fiberscope guidance. RESULTS: The nasopharyngeal temperatures were recorded at seven time intervals along with esophageal temperature. Mean temperatures were calculated at three different sites. The degree of agreement between two methods at seven time intervals was also calculated. Both methods had good correlation with esophageal temperature. Depth of insertion of temperature probes was documented. There was difference in depth of insertion of temperature probe of around 4.26 cm between two methods, probe length from philtrum to tragus (D(1)) being longer than distance from fossa of Rosenmuller to nares (D(2)). CONCLUSIONS: Nasopharyngeal temperature measured at fossa of Rosenmuller with probe inserted by fiberscope-guided method and that measured by landmark-based method with probe inserted according to philtrum-tragus distance shows good correlation with esophageal temperature.