title: [The prevention of the ear barotrauma by positive pressure on nasopharynx].
abstract: OBJECTIVE
  To explore if the ear barotrauma could be prevented or not if the provided nasopharyngeal pressure is higher than the Eustachian tube resistance during the pressure increases in the hyperbaric chamber.
  
  
  METHODS
  Eight volunteers of healthy men were divided into 4 groups, with 2 persons in each group who were the tested and the control for each other. The positive pressure of 6kPa was given via mask to the nasopharynx of the tested, while the control took normal breath. The pressure in the hyperbaric chamber was increased by 5kPa with the velocity of 0.5kPa/s. No positive or negative measurement to open Eustachian tube was allowed for both tested and controls. The pressure within the tympanic cavity was measured. Similarly, the pressure in the hyperbaric chamber was increased by 20kPa with the same velocity. The tested were not allowed to adjust the Eustachian tube, while the controls could do so. The pressure within the tympanic cavity was measured once again.
  
  
  RESULTS
  When 5 kPa in the hyperbaric chamber was reached, the pressure within the tympanic cavity of the tested and the control was -11.2 daPa and -168.6 daPa (P < 0.01), respectively. When 20 kPa was reached, the pressure within the tympanic cavity of the tested and the control was -8.3 daPa and -7.6 daPa (P > 0.05), respectively. Ear barotrauma could be prevented by providing positive pressure which is higher than the Eustachian tube resistance through mask to the nasopharynx.
authors.affiliation: Department of Information, Lushan Sanatorium of PLA, Lushan 332900, China. wu7hao@126.com
authors.forename: Jialin
authors.initials: J
authors.lastname: Wu
authors.forename: Zhangqing
authors.initials: Z
authors.lastname: Zheng
authors.forename: Xianqiao
authors.initials: X
authors.lastname: Wang
authors.forename: Hongxing
authors.initials: H
authors.lastname: Mao
authors.forename: Ping
authors.initials: P
authors.lastname: Cheng
mesh_terms: D000293:Adolescent; D000328:Adult; D001469:Barotrauma / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D006931:Hyperbaric Oxygenation / Q000295:instrumentation*; D008297:Male; D008397:Masks; D009305:Nasopharynx; D055815:Young Adult