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document
Nitrous oxide diffusion into tracheal tube cuffs -- efficacy of a new prototype cuff pressure release valve . BACKGROUND The aim of this study was to evaluate the performance of a new cuff pressure release valve ( CPRV ) , in which the release pressure can be adjusted from 10 to 25 cmH2O , particularly intended to control pressure in paediatric cuffed tracheal tubes and to avoid cuff hyperinflation caused by N2O diffusion . METHODS In vitro : the PRV was set to 10 , 15 , 20 or 25 cmH2O release pressure and connected to a cuffed tube placed into a box flushed with 66 % N2O in O2 . The cuff pressure was monitored with and without CPRV for 60 min . Experiments were performed four times using two different CPRVs . In vivo : with Institutional Review Board approval , CPRV was studied in 50 children undergoing general anaesthesia with tracheal intubation and standardized anaesthesia technique ( including 66 % N2O in O2 ) and ventilator settings . Patients were randomized into two groups ( with and without CPRV ) . The cuff pressure baseline was 20 cmH2O and CPRV was set to 25 cmH2O . If the cuff pressure exceeded 25 cmH2O , it was manually released to 20 cmH2O . The numbers of deflations in both groups were noted and compared by Mann-Whitney U-test ( P < 0.05 ) . RESULTS In vitro : the cuff pressure exceeded 50 cmH2O after 60 min without CPRV , but did not exceed the settings with CPRV . In vivo : there was no need to manually deflate the cuff in the CPRV group but , in every patient in the control group , three ( two to seven ) deflating manoeuvres were required within the first hour of anaesthesia ( P < 0.0001 ) . CONCLUSION The CPRV allows reliable cuff pressure release at various pressure levels and reliably prevents cuff pressure increases caused by N2O .
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Intervention_Other
cuff pressure release valve
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Intervention_Other
cuff pressure release valve
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Intervention_Physical
(
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Intervention_Other
with
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Intervention_Physical
and without
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Intervention_Other
CPRV
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Outcome_Physical
cuffs --
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Outcome_Other
efficacy
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Outcome_Other
performance
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Outcome_Physical
cuff pressure
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Outcome_Physical
cuff pressure
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Outcome_Physical
cuff pressure
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Outcome_Physical
cuff pressure
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Outcome_Physical
cuff pressure
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Outcome_Physical
reliable cuff pressure release
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Outcome_Physical
cuff pressure
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Participant_Condition
paediatric cuffed tracheal tubes
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Participant_Sample-size
50
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Participant_Age
children
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Participant_Condition
general anaesthesia with tracheal intubation and standardized anaesthesia technique