title: Continuous gastric suctioning decreases measured esophageal temperature during general anesthesia.
abstract: OBJECTIVE
  This study sought to determine whether continuous gastric suctioning influences esophageal temperature measurements.
  
  
  METHODS
  This study evaluated 21 patients scheduled for extremity or lower abdominal surgery. After induction of general endotracheal anesthesia, an orogastric tube, and esophageal and nasopharyngeal temperature probes were placed in functional positions. Baseline esophageal (Tes) and nasopharyngeal (Tnas) temperatures were recorded and the orogastric tube was placed on continuous suction. After the first 11 patients (Group I) were studied, 10 additional patients (Group II) were studied with more frequent data collection to improve the time resolution of temperature changes. Temperatures were recorded for patients in Group I at 2 and 10 min with suctioning and 10 min after cessation of suctioning. In Group II, temperatures were recorded at 1, 2, 5 and 10 min with suctioning and 10 min after cessation of suctioning. Analysis of data was performed using repeated measures analysis of variance and paired t-tests with the Bonferroni correction.
  
  
  RESULTS
  In Group I, Tes decreased significantly from 35.9 +/- 0.2 degrees C (mean +/- SE) to 35.1 +/- 0.4 degrees C at 2 min and 34.8 +/- 0.3 degrees C at 10 min of suctioning (p < 0.01). Ten minutes after cessation of suctioning, Tes was not significantly different from the baseline measurement. Tnas did not change significantly over the 20 min observation period. In Group II, Tes continually decreased from 36.2 +/- 0.1 degrees C to 34.8 +/- 0.3 degrees C after 10 min of suctioning (p < 0.006) and returned to near baseline 10 min after cessation of suctioning. There was no significant change in Tnas over the 20 min observation period.
  
  
  CONCLUSIONS
  We conclude that continuous gastric suctioning decreases esophageal temperature measurements. This phenomenon should be recognized as an artifactual change in esophageal temperature and not a reflection of core temperature.
authors.affiliation: Department of Anesthesiology, Wilford Hall Medical Center, TX, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Nelson
authors.forename: T E
authors.initials: TE
authors.lastname: Grissom
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D000770:Anesthesia, Endotracheal; D001831:Body Temperature; D004947:Esophagus / Q000502:physiology*; D006801:Humans; D016343:Monitoring, Intraoperative; D019023:Stethoscopes; D013270:Stomach; D013396:Suction; D013997:Time Factors