Trial document




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  DRKS00008719

Trial Description

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Title

Comparison of two different strategies to control the intra-cuff pressure during laryngeal mask anaesthesia - digital palpation technique versus continuous cuff pressure measurement

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Trial Acronym

LMA

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URL of the Trial

http://none

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Brief Summary in Lay Language

During general anaesthesia the respiratory tract must be protected using either an endotracheal tube or a laryngeal mask. The laryngeal mask is composed of a slightly curved tube and an oval-shaped mask which forms an airtight seal around the laryngeal perimeter. The mask itself is connected with a thin tube, a pilot balloon and a terminally located valve for air inflation to block the cuff of the mask. It is believed that due to the inflation of air the laryngeal mask moves by self positioning into the correct position. The question arises: What is the appropriate air volume to achieve this. Most anaesthetists use the digital palpation of the pilot balloon to estimate the cuff pressure and thus to assess the appropriate air volume. However, in clinical practice the inflation technique is often imparted without recourse to evidence, or even to the instruction leaflet. In many cases laryngeal masks are overinflated leading to problems such as sore throats, dysphonia, dysphagia and recurrent laryngeal nerve palsy. It has been shown that continuous measurement of cuff pressure is helpful to avoid such pharyngolaryngeal complications. It is the aim of this study to compare both techniques to control the intra-cuff pressure.

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Brief Summary in Scientific Language

The laryngeal mask (LMA) is a device increasingly used for airway management in general anaesthesia as well as in emergency medicine. There has been a growing interest to use LMAs, since they can be placed quickly and effectively with minimal training and securing the airway is possible even in patients with difficult-to-manage airways. Despite these advantages and the easy handling LMAs are often used inappropriately and sometimes harmful in clinical routine. For example it has been shown repeatedly in LMAs that injecting an air volume as recommended by the manufacturer can result in cuff pressures twice the adviced maximum of 60 cmH2O and even as high as 200 cmH2O. In some reports, 70% of LMAs were overinflated leading to postoperative sore throat, dysphonia and dysphagia as well as impairment of its primary function, the airway seal. For that reason the question arises: What is the appropriate method to control the intra-cuff pressure. Most anaesthetists use the digital palpation of the pilot balloon as monitoring technique. Alternatively, the continuous measurement of cuff pressure by manometry can be used.
It is the aim of the present study to compare both techniques and to investigate their influence on the frequency of pharyngolaryngeal complications.

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Organizational Data

  •   DRKS00008719
  •   2015/07/03
  •   [---]*
  •   yes
  •   Approved
  •   EA4/071/15, Ethik-Kommission der Charité -Universitätsmedizin Berlin-
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Secondary IDs

  • [---]*
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Health Condition or Problem studied

  •   The participants of the study will be recruited consecutively from patients undergoing elective surgery under general anesthesia using a laryngeal mask. Medical specialities: surgery, orthopedic surgery, gynecology, plastic surgery
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Interventions/Observational Groups

  •   Group 1 (Digital palpation technique)
    LMAs will be inflated by applying the air volume recommended by the manufacturer (i.e. 20 ml size III, 30 ml size IV and 40 ml size V).
    Females below 50 kg receive size III, females above 50 kg receive size IV and males receive size V.
    In case of an incorrect position of the LMA (audible signs of air leakage, insufficient tidal volume), stepwise inflation of air will be performed additionally (maximum 5 ml).
    Is there no acceptable result due to this manoeuver, the LMA should be removed and a new attempt with a device of different size should be tried.
    The entire volume of air inflated will be recorded.
    After successful insertion of the LMA, the cuff pressure will be estimated by the anaesthetist as well as by the nurse using the digital palpation technique. Both values will be documented. Afterwards, an independent investigator will conduct a single cuff pressure measurement, but without informing the stuff.
  •   Group 2 (Continuous measurement of cuff pressure)
    Stepwise inflation of air into the cuff will be performed until a cuff pressure is achieved allowing a sufficient positive pressure ventilation.
    A maximum cuff pressure of 60 cmH2O will be observed and monitored during the entire anaesthesia.
    Is there no acceptable result due to this manoeuver, the LMA should be removed and a new attempt with a device of different size should be tried.
    At the end of operation/anaesthesia the LMA will be removed completely inflated and rinsed with water. Subsequently, the complete air volume will be removed from the cuff using a syring.
    Afterwards, this air volume will be measured and compared with the air volume recommended by the manufacturer.

    The sizes of laryngeal masks will be assigned in the same way as Group 1
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Characteristics

  •   Interventional
  •   [---]*
  •   Randomized controlled trial
  •   Open (masking not used)
  •   [---]*
  •   Active control
  •   Treatment
  •   Parallel
  •   N/A
  •   N/A
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Primary Outcome

Frequency and severity of sore throats (acquired by postoperative questionnaire)
Modified external quality assurance questionnaire EQS Hamburg for anesthesia. The survey will be conducted on the discharge day of the patients.

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Secondary Outcome

Frequency and severity of hoarseness (p.o. questionnaire, Modified and evaluated Hamburg EQS-questionnaire, conducted on discharge day)
Frequency and severity of dysphagia (p.o. questionnaire, Modified and evaluated Hamburg EQS-questionnaire, conducted on discharge day)
Duration of afflictions (p.o. questionnaire)

Quality of airway (intraoperative evaluation, 10 minutes after induction of anesthesia)
Inflated air volume (postoperative evaluation, at the end of operation procedure)
Maximum cuff pressure (postoperative evaluation, at the end of operation procedure)
Accordance between measured and estimated value (postoperative evaluation, at the end of operation procedurs).

All measurements as well as documentation will be performed by an independent investigator

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Countries of Recruitment

  •   Germany
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Locations of Recruitment

  • Medical Center 
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Recruitment

  •   Planned
  •   2015/08/01
  •   180
  •   Monocenter trial
  •   National
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Inclusion Criteria

  •   Both, male and female
  •   18   Years
  •   no maximum age
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Additional Inclusion Criteria

Patients undergoing elective surgery under laryngeal mask anaesthesia
Minimum age of 18 years
ASA-classification I-III
Good knowledge of German for understanding

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Exclusion Criteria

Lack of willingness to accept storage and transfer of pseudonymised health data
Emergency surgery
Pregnancy
Inoperable regarding the ASA-classification
All operation procedures not suited for laryngeal mask anaesthesia
Lack of an informed consent
Age under 18 years
Participation in an other study during the last three month
Mental disorders

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Addresses

  • start of 1:1-Block address primary-sponsor
    • Park-Klinik WeissenseeAbteilung Anästhesiologie Intensivmedizin
    • Mr.  Privatdozent Dr. med.  Mario  Hensel 
    • Schönstr. 80
    • 13086  Berlin
    • Germany
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    • Park-Klinik WeissenseeAbteilung Anästhesiologie Intensivmedizin
    • Mr.  Privatdozent Dr. med.  Mario  Hensel 
    • Schönstr. 80
    • 13086  Berlin
    • Germany
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    • Park-Klinik Weissensee
    • Mr.  Privatdozent Dr. med.  Mario  Hensel 
    • Abteilung Anästhesiologie Intensivmedizin
    • 13086  Berlin
    • Germany
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Sources of Monetary or Material Support

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    • Park-Klinik WeissenseeAbteilung Anästhesiologie Intensivmedizin
    • Mr.  Privatdozent Dr. med.  Mario  Hensel 
    • Schönstr. 80
    • 13086  Berlin
    • Germany
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Status

  •   Recruiting planned
  •   [---]*
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Trial Publications, Results and other Documents

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* This entry means the parameter is not applicable or has not been set.