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Middle Ear Pressure Changes after Nitrous Oxide Anesthesia and Its Effect on Postoperative Nausea and Vomiting
Author(s) -
Nader Nader D.,
Simpson George,
Reedy Roberta L.
Publication year - 2004
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200405000-00018
Subject(s) - tympanometry , anesthesia , medicine , nausea , postoperative nausea and vomiting , vomiting , incidence (geometry) , middle ear , surgery , hearing loss , audiometry , audiology , physics , optics
Objectives/Hypothesis: This study was designed to explore the relationship between changes in middle ear pressure associated with inhalational anesthesia and the incidence of postoperative nausea and vomiting (PONV). Study Design: Prospective, randomized. Methods: Middle ear compartment pressures were measured by tympanometry in 27 randomly assigned knee arthroscopy patients throughout the surgical procedure as well as into recovery. Results: A positive correlation between the maximum positive pressure (MPP) and maximum negative pressure (MNP) gradient and PONV was demonstrated ( P < .05). The incidence of PONV in the nitrous oxide (N 2 O) treatment group was 6 of 16 patients, whereas only 2 of 11 patients in the control group developed nausea, vomiting, and vertigo symptoms. Those patients that did not experience PONV demonstrated a median MPP of 155 with a median MNP of −52. The patients that experienced PONV exhibited a median MPP of 179 with a median MNP of −164. This demonstrates a significant increase in the incidence of PONV in the N 2 O treatment group. Conclusions: Barometric changes in the middle ear contribute to the incidence of PONV induced by N 2 O.