OBJECTIVETo evaluate the effectiveness of two training methods for avoiding excessive inflation of laryngeal mask airway(LMA)Supreme.

METHODSTotally 41 anesthesiologists were randomly divided into hand touch group(H group,n=20)and short-term pressure gauge training group(G group,n=21). Before training,subjects were asked to inflate the cuff of LMA Supreme to two target pressures,30 cmH(2)O and 60 cmH(2)O, according to their own experiences. The actual cuff pressures were recorded as baseline pressures. Subjects in H group then received the training of hand touch:touch the vermilion of the lip and apex nasi with the left ring finger and feel the hardness. A cuff pressure with hardness similar to the vermilion of the lip was defined as 30 cmH(2)O, and similar to the apex nasi as 60 cmH(2)O. Subjects in G group were asked to inflate the cuff with a pressure gauge and feel the hardness of the cuff when the pressure reached 30 cmH(2)O and 60 cmH(2)O. After one-week training,two groups of subjects repeated the cuff inflation test. Actual cuff pressures after training were also recorded and compared with the baseline pressures. Results Actual cuff pressures after training[Group H:(39.7±15.7) cmH(2)O(P=0.00);Group G:(26.2±13.2) cmH(2)O(P=0.03)]were significantly lower than baseline pressures in both groups when the target cuff pressure was 30 cmH(2)O, and the differences were not statistically significant between these two groups(P=0.06). When the target pressure was 60 cmH(2)O,the actual cuff pressure of H group [(91.1±24.3)cmH(2)O] was significantly higher than that of G group [(58.1±15.4) cmH(2)O (P=0.01)]. However,the actual cuff pressure of G group was similar to the target pressure.

CONCLUSIONThe two training methods are equally effective when the target pressure is 30 cmH(2)O, while short-term pressure gauge training method is superior when the target pressure is 60 cmH(2)O.

This paper describes to design and to examine the mechanical characteristics of high frequency jet ventilator. The device consists of Phase lock loop (PLL) system, solenoid valve driving control part and Air regulating system. This study is carried out by changing several factors such as endotracheal tube (E.T. tube) diameter, injector cannula diameter, 1%, and frequency (breaths/min.) having direct effects on the gas exchange as well as parameters of the entrained gas by venturi effect, so as to measure the tidal volume and minute volume. This system characteristics were as follows: 1) Frequency: 6-594 bpm 2) Inspiration time: 1-99% 3) Variance of input air pressure: 1-30 PSI
Air Pressure ; Catheters ; Tidal Volume ; Ventilators, Mechanical*

OBJECTIVETo develop a method for determination of 2, 4-dichlorophenoxyacetic acid (2, 4-D) in the air of workplace by high-performance liquid chromatography.

METHODS2, 4-D was collected by ultrafine glass filters, desorbed by methanol, separated by a C18 column, and detected by a UV detector. Identification and quantification of 2, 4-D were performed by retention time and peak areas, respectively.

RESULTSThe linear range of the test was 2∼200 µg/ml; the elution efficiency was 94.6%- 95.9%; the limit of detection (S/N = 3) was 0.034 µg/ml (injection volume of 20 µl eluant); the lower limit of quantification (S/N = 10) was 0.11 µg/ml; the minimum detectable concentration was 0.011 mg/m(3); the minimum quantifiable concentration was 0.037 mg/m(3) (with sampled air volume of 45 L).

CONCLUSIONThis method is convenient and simple in sample collection and preparation, and satisfies all methodological requirements. Therefore, this method is useful for the determination of 2, 4-D in the air of workplace.

Air ; analysis ; Air Pollutants, Occupational ; analysis ; Chromatography, High Pressure Liquid ; methods ; Polycyclic Aromatic Hydrocarbons ; analysis ; Workplace

Air ; analysis ; Air Pollutants ; analysis ; Aldehydes ; analysis ; Chromatography, High Pressure Liquid ; methods

OBJECTIVETo establish a method for determining brodifacoum in workplace air by high-performance liquid chromatography (HPLC).

METHODSBrodifacoum in workplace air was collected with a polytetrafluoroethylene filter and desorbed by mixed solution of methanol and dichloromethane (20:80, V:V), and was then separated using an ODS column and determined by an ultraviolet detector; retention time was used for identification, and peak area was used for quantification.

RESULTSThe concentration of brodifacoum showed a linear relationship with peak area within 0.2∼10.0 µg/ml; the elution efficiency was 91.6%∼95.1%; the detection limit was 0.08 µg/ml (injection volume: 20 µl eluate); the minimum detectable concentration was 0.000 67 mg/m(3) (calculated by 240 L air sample).

CONCLUSIONThis HPLC method is convenient and simple for air collection and sample preparation and meets the methodological requirements. Therefore, this method can be used for the determination of brodifacoum in workplace air.

Cerebral arterial air embolism (CAAE), although infrequent, is a complication that can occur at any time during an invasive medical procedure. We experienced two cases of CAAE during cerebral angiography accidentally. The author reports the two cases of CAAE wherein air emboli dissolved spontaneously and immediately under normal atmospheric pressure, not under therapeutic hyperbaric environment. One of the cases shows entire dissolution of the air embolus on the moving image. This report shows that arterial air embolus can be absorbed spontaneously, and air embolus size is one of the factors that influence air embolus dissolution besides hyperbaric oxygen condition.
Absorption* ; Atmospheric Pressure ; Cerebral Angiography ; Embolism* ; Embolism, Air ; Oxygen

OBJECTIVES: Patients with bilateral vocal fold paralysis (BVFP) theoretically have difficulty producing voiceless consonants. However, perceptual studies have revealed clear production of voiceless consonants with good articulation scores in nontracheostomized patients. The purpose of this study was to clarify the production of voiceless stops during articulation in patients with BVFP compared to normal speakers. METHODS: The perceptual, acoustic, and aerodynamic characteristics of patients with BVFP and those with normal speech were investigated with special reference to voiceless stop consonants. Test words were prepared to place the stop consonants in different phonological environments, and were all nonsense words. RESULTS: The patients with BVFP perceptually produced the three types of stops successfully. However, they acoustically varied voice onset time to produce phonetically representative stops but decreased voice onset time of /ph/ and /p/ compared to those of normal speakers. These patients may properly control air pressure to produce the three types of stop consonants similar to normal speakers. CONCLUSION: The patients with BVFP realized the distinctions between the three types of stops similar to the normal speakers. Although vocal mobility was absent in the patients with BVFP, voice onset time, vowel duration, closure duration, and air pressure were similar to those of normal speakers.
Acoustics ; Air Pressure ; Humans ; Paralysis* ; Tracheotomy* ; Vocal Cords* ; Voice

Air ; analysis ; Chromatography, High Pressure Liquid ; methods ; Polyamines ; analysis ; Workplace

OBJECTIVETo investigate the impact of cuff pressure on airway leak pressure in laryngeal mask airway(LMA)Supreme and Flexible.

METHODSPatients about to have elective breast surgery were divided into Supreme group(35 cases)and Flexible group(33 cases). After general induction of anesthesia,LMA Supreme or Flexible was inserted by one anesthesiologist. We confirmed the LMA location,adjusted the cuff pressure,and recorded the peak airway leak pressures under different cuff pressures(10,20,30,40,and 50 cmH2O).

RESULTSIn Supreme group,peak airway leak pressures [(24.46±5.43),(25.11±5.51),(25.86±5.57),(26.17±5.72)cmH2O] under 20,30,40,and 50 cmH2O cuff pressure showed no significant difference(P>0.05)between each other,but significantly higher than that under 10 cmH2O cuff pressure(20.80±4.63)cmH2O(P<0.05). And in the Flexible group,peak airway leak pressures [(20.09±2.98),(20.70±3.08),(21.21±3.15)cmH2O] under 30,40,50 cmH2O cuff pressure also showed no significant difference(P>0.05)between each other,but significantly higher than those under 10 or 20 cmH2O cuff pressure [(17.52±2.39),(18.61±2.42)cmH2O]. Mean peak airway leak pressure [(25.40±5.52) cmH2O] of LMA Supreme was significantly higher than that of LMA Flexible(20.67±3.06)cmH2O(P<0.05).

CONCLUSIONSMean airway leak pressure of LMA Supreme is higher than LMA Flexible. The lowest cuff pressure to meet the tightness requirement with LMA Supreme is 20 cmH2O,which is lower than Flexible(30 cmH2O).