<clinical_study>
  <!-- This xml conforms to an XML Schema at:
    https://clinicaltrials.gov/ct2/html/images/info/public.xsd -->
  <required_header>
    <download_date>ClinicalTrials.gov processed this data on September 20, 2023</download_date>
    <link_text>Link to the current ClinicalTrials.gov record.</link_text>
    <url>https://clinicaltrials.gov/ct2/show/NCT03802383</url>
  </required_header>
  <id_info>
    <org_study_id>3531/29.06.2018</org_study_id>
    <nct_id>NCT03802383</nct_id>
  </id_info>
  <brief_title>The Relationship Between Trans-diaphragmatic Pressure and Diaphragmatic Contraction</brief_title>
  <official_title>A Study on the Relationship Between the Trans-diaphragmatic Pressure and the Contraction of the Diaphragm</official_title>
  <sponsors>
    <lead_sponsor>
      <agency>University of Thessaly</agency>
      <agency_class>Other</agency_class>
    </lead_sponsor>
  </sponsors>
  <source>University of Thessaly</source>
  <oversight_info>
    <has_dmc>No</has_dmc>
    <is_fda_regulated_drug>No</is_fda_regulated_drug>
    <is_fda_regulated_device>No</is_fda_regulated_device>
  </oversight_info>
  <brief_summary>
    <textblock>
      Through this study the investigators aim to clarify the relationship between&#xD;
      trans-diaphragmatic pressure and various parameters of the diaphragmatic contraction&#xD;
      evaluated by ultrasound. The following parameters will be studied: esophageal pressure,&#xD;
      gastric pressure, diaphragm thickness at peak inspiration (Tdi,pi), diaphragm thickness at&#xD;
      end expiration (Tdi,ee), diaphragm thickening (Tdi,pi - Tdi,ee), diaphragm thickness fraction&#xD;
      [TFdi=(Tdi,pi - Tdi,ee)/Tdi,ee], diaphragm excursion (Di,e), Maximal Inspiratory pressure&#xD;
      (M.I.P), Pressure-Time product of the trans-diaphragmatic pressure (PΤPdi),Tension Time&#xD;
      Diaphragm Index (T.T.Di) and the rapid shallow breathing index (R.S.B.I.). These measurements&#xD;
      will be made in two phases.Firstly, during the spontaneous breathing trial and secondly&#xD;
      during spontaneous breathing through an airway of reduced diameter.Furthermore, during the&#xD;
      M.I.P. test the aforementioned ultrasound parameters will be measured. The aim of this study&#xD;
      is to discover new means of a successful prediction of weaning in the first 48 hours&#xD;
      following extubation.&#xD;
    </textblock>
  </brief_summary>
  <detailed_description>
    <textblock>
      Protocol&#xD;
&#xD;
      The patients will enter a Spontaneous Breathing Trial (S.B.T.) for sixty minutes. During the&#xD;
      S.B.T. the desirable measurements will be made: transdiaphragmatic pressure, diaphragm&#xD;
      thickening, Tdi,pi , Tdi,ee , TFdi, Di,e, Maximal Inspiratory Pressure (M.I.P.) , Rapid&#xD;
      Shallow Breathing Index (R.S.B.I.). If the S.B.T. is successful then the patient will be&#xD;
      removed from the mechanical ventilator. For the next 48 hours the patient will be monitored&#xD;
      for distress signs and thus be reintubated or if the weaning of the patient was successful&#xD;
      extubation.&#xD;
&#xD;
      Flow chart of the study&#xD;
&#xD;
        1. The patient meets the S.B.T. criteria.&#xD;
&#xD;
        2. The patient is placed in a semi recumbent position.&#xD;
&#xD;
        3. A nasogastric tube attached with two balloons, which are connected with a pressure&#xD;
           transducer, one placed in the stomach and the other one in the lower third of the&#xD;
           esophagus.&#xD;
&#xD;
        4. The balloons will be connected with a Hans Rudolph pneumotachograph for the measurement&#xD;
           of the tidal volume, the flow and the esophageal pressure.&#xD;
&#xD;
        5. An occlusion test will be performed to make sure the esophageal balloon is correctly&#xD;
           placed.&#xD;
&#xD;
        6. Measurement of Pes, Pgas, M.I.P., and simultaneous sonographic measurements (Diaphragm&#xD;
           thickening,Tdi,pi, Tdi,ee, Di,e,TFdi) during the S.B.T. with the patient being in&#xD;
           t-tube.&#xD;
&#xD;
        7. Measurement of the same parameters during an S.B.T. with an airway of reduced diameter.&#xD;
&#xD;
        8. The patient will be reintubated for 60 minutes.&#xD;
&#xD;
        9. The S.B.T. is repeated and the R.S.B.I. will be calculated.&#xD;
&#xD;
       10. If the S.B.T. is successful according to the R.S.B.I. the patient will be disconnected&#xD;
           from the mechanical ventilation.&#xD;
&#xD;
       11. Monitoring of the patient for the next 48 hours, for the extubation respiratory distress&#xD;
           syndrome or reintubation for another reason.&#xD;
&#xD;
       12. Further monitoring for 30 days in order to measure the time spent in mechanical&#xD;
           ventilation&#xD;
&#xD;
      Definitions&#xD;
&#xD;
      Transdiaphragmatic pressure&#xD;
&#xD;
      Pdi will be measured with the use of a nasogastric catheter which has 2 balloons attached at&#xD;
      25 cm and 10 cm from it's distal end. The balloons, of 7 cm length, will be connected with a&#xD;
      pressure transducer and with the use of a linear pneumotachometer Hans Rudolph RSS 100HR the&#xD;
      graphic representation of the pressures will be displayed in a computer monitor. The balloons&#xD;
      will contain 0,5-1 ml of air and will be placed in the stomach and the lower third of the&#xD;
      esophagus. To ensure the correct positioning of the balloons an occlusion test (Baydur test)&#xD;
      will be performed ,where the similar fluctuations between the esophageal and the airway&#xD;
      pressure will be affirmative. As long as the stomach balloon is concerned the positive&#xD;
      pressures during the inspiration will be affirmative of the correct positioning.&#xD;
&#xD;
      Pressure Time Index&#xD;
&#xD;
      P.T.I. is the product of the ratio of the mean inspiratory pressure to the maximal&#xD;
      inspiratory pressure (Pavg/Mip) and the ratio of the inspiratory time to the total duration&#xD;
      of the inspiratory cycle (Ti/Ttot).The usefulness of the P.T.I. consists that it measures the&#xD;
      total energy cost of breathing.&#xD;
&#xD;
      P.T.I.=(Pavg/M.I.P.)x(Ti/Ttot) where as a Pavg is considered the airway pressure in the&#xD;
      middle of the inspiratory phase (ti/2).&#xD;
&#xD;
      Tension Time Diaphragm Index&#xD;
&#xD;
      Ttdi is used as an index of diaphragmatic exhaustion. Measurements above 0,15 are indicative&#xD;
      of the diaphragmatic incapability to maintain spontaneous breathing for more than 45 minutes,&#xD;
      whence the naming of Ttdi critical&#xD;
&#xD;
      Ttdi = (Pdi/Pdi,max)x(TixTtot)&#xD;
&#xD;
      Rapid Shallow Breathing Index&#xD;
&#xD;
      Rapid Shallow Breathing Index (R.S.B.I.) is a method used for predicting the weaning outcome.&#xD;
      It is measured during spontaneous breathing and equates to the ratio of respiratory rate per&#xD;
      minute (RR) to the tidal volume (Vt) expressed in liters.&#xD;
&#xD;
      R.S.B.I. = RR/Vt&#xD;
&#xD;
      It has been shown that an R.S.B.I. values below 105 breaths/min/L can predict a successful&#xD;
      weaning.&#xD;
&#xD;
      Maximal Inspiratory Pressure&#xD;
&#xD;
      Maximal Inspiratory Pressure (M.I.P.) is used as a predictive factor of the weaning outcome.&#xD;
      It is measured with a manometer placed in a fully occluded airway, while the patient tries to&#xD;
      breathe through it for 20 seconds. The highest pressure value is named M.I.P. It has been&#xD;
      shown that values below -25 cmH2O are indicative of a positive weaning outcome.&#xD;
&#xD;
      Diaphragm Ultrasound&#xD;
&#xD;
      The diaphragmatic function is assessed during spontaneous breathing and during breathing with&#xD;
      an airway of reduced diameter. The diaphragmatic movement is assessed with ultrasound&#xD;
      (Phillips iE33) using a Linear 3-11 MHz head. The ultrasound probe is placed in the mid&#xD;
      axillary line perpendicular to the zone of apposition between the 8th-10th intercostal&#xD;
      spaces. In this position, the diaphragm is shown as a non-echogenic layer between two&#xD;
      echogenic layers which represent the diaphragmatic pleura and the abdominal peritoneum. With&#xD;
      this technique the diaphragmatic thickening (Tdi,pi - Tdi,ee), diaphragmatic thickness at&#xD;
      end-expiration (Tdi,ee) and end-inspiration (Tdi,pi), diaphragmatic excursion Di,e and&#xD;
      diaphragmatic thickening fraction TFdi are measured. All the measurements are made using&#xD;
      M-Mode Sonography.&#xD;
    </textblock>
  </detailed_description>
  <overall_status>Unknown status</overall_status>
  <last_known_status>Recruiting</last_known_status>
  <start_date type="Actual">June 29, 2018</start_date>
  <completion_date type="Anticipated">July 30, 2021</completion_date>
  <primary_completion_date type="Anticipated">December 30, 2019</primary_completion_date>
  <study_type>Observational</study_type>
  <has_expanded_access>No</has_expanded_access>
  <study_design_info>
    <observational_model>Cohort</observational_model>
    <time_perspective>Prospective</time_perspective>
  </study_design_info>
  <primary_outcome>
    <measure>The correlation of inspiratory esophageal pressure, as assessed by esophageal manometry, to diaphragmatic thickness, as assessed by ultrasound, in patients who are weaned from mechanical ventilation.</measure>
    <time_frame>1 year</time_frame>
    <description>The authors will study the correlation of inspiratory esophageal pressure, as assessed by esophageal manometry (values in cm H2O), to diaphragmatic thickness, as assessed by ultrasound (values in cm), in patients who are weaned from mechanical ventilation.Then a comparison will be made between the patients who failed and those who succeeded. Ten consecutive tidal breaths will be studied both by esophageal manometry and ultrasound of the diaphragm in each patient.</description>
  </primary_outcome>
  <enrollment type="Anticipated">30</enrollment>
  <condition>Weaning Failure</condition>
  <condition>Respiratory Paralysis</condition>
  <condition>Respiratory Failure</condition>
  <eligibility>
    <study_pop>
      <textblock>
        Patients in the Intensive Care Unit of the University Hospital of Larissa&#xD;
      </textblock>
    </study_pop>
    <sampling_method>Probability Sample</sampling_method>
    <criteria>
      <textblock>
        Inclusion Criteria:&#xD;
&#xD;
        Patients meeting the following standards.&#xD;
&#xD;
          -  Respiratory Criteria&#xD;
&#xD;
               -  PaO2≥ 60mmHg with Fraction of Inspired Oxygen (FiO2) ≤ 40-50% &amp; Positive End&#xD;
                  Expiratory Pressure (PEEP) ≤ 5-8 cm H2O&#xD;
&#xD;
               -  PaCO2 normal or at the level of reference (allowed hypercapnia is allowed)&#xD;
&#xD;
               -  Patient is able to start ventilatory effort&#xD;
&#xD;
          -  Cardiovascular Criteria&#xD;
&#xD;
               -  Absence of myocardial ischemia&#xD;
&#xD;
               -  Heart Rate ≤140 bpm&#xD;
&#xD;
               -  Arterial Pressure normal without vasoconstriction or with minimum&#xD;
                  vasoconstriction support&#xD;
&#xD;
          -  Adequate level of consciousness&#xD;
&#xD;
             o Glasgow Coma Scale (GCS ≥ 13)&#xD;
&#xD;
          -  Absence of other reversible comorbidities&#xD;
&#xD;
               -  Afebrile Patient&#xD;
&#xD;
               -  Without important electrolyte disorders&#xD;
&#xD;
        Exclusion Criteria:&#xD;
&#xD;
          -  Obese patients with B.M.I. &gt;35&#xD;
&#xD;
          -  pregnant women&#xD;
&#xD;
          -  patients &lt;18 years old&#xD;
      </textblock>
    </criteria>
    <gender>All</gender>
    <minimum_age>18 Years</minimum_age>
    <maximum_age>N/A</maximum_age>
    <healthy_volunteers>No</healthy_volunteers>
  </eligibility>
  <overall_contact>
    <last_name>Demosthenes Makris</last_name>
    <phone>+306943706079</phone>
    <email>appollon7@hotmail.com</email>
  </overall_contact>
  <overall_contact_backup>
    <last_name>APOSTOLOS-ALKIVIADIS MENIS</last_name>
    <email>menis.ap.alk@gmail.com</email>
  </overall_contact_backup>
  <location>
    <facility>
      <name>Critical Care Unit</name>
      <address>
        <city>Larissa</city>
        <state>Thessaly</state>
        <country>Greece</country>
      </address>
    </facility>
    <status>Recruiting</status>
    <contact>
      <last_name>Dimosthenis Makris</last_name>
    </contact>
  </location>
  <location_countries>
    <country>Greece</country>
  </location_countries>
  <reference>
    <citation>Brochard L. (1991) Transdiaphragmatic Pressure. In: Benito S., Net A. (eds) Pulmonary Function in Mechanically Ventilated Patients. Update in Intensive Care and Emergency Medicine, vol 13. Springer, Berlin, Heidelberg</citation>
  </reference>
  <reference>
    <citation>Mauri T, Yoshida T, Bellani G, Goligher EC, Carteaux G, Rittayamai N, Mojoli F, Chiumello D, Piquilloud L, Grasso S, Jubran A, Laghi F, Magder S, Pesenti A, Loring S, Gattinoni L, Talmor D, Blanch L, Amato M, Chen L, Brochard L, Mancebo J; PLeUral pressure working Group (PLUG-Acute Respiratory Failure section of the European Society of Intensive Care Medicine). Esophageal and transpulmonary pressure in the clinical setting: meaning, usefulness and perspectives. Intensive Care Med. 2016 Sep;42(9):1360-73. doi: 10.1007/s00134-016-4400-x. Epub 2016 Jun 22.</citation>
    <PMID>27334266</PMID>
  </reference>
  <reference>
    <citation>Turnbull D, Webber S, Hamnegard CH, Mills GH. Intra-abdominal pressure measurement: validation of intragastric pressure as a measure of intra-abdominal pressure. Br J Anaesth. 2007 May;98(5):628-34. doi: 10.1093/bja/aem060.</citation>
    <PMID>17456490</PMID>
  </reference>
  <reference>
    <citation>Beaulieu Y, Marik PE. Bedside ultrasonography in the ICU: part 1. Chest. 2005 Aug;128(2):881-95. doi: 10.1378/chest.128.2.881.</citation>
    <PMID>16100182</PMID>
  </reference>
  <reference>
    <citation>Beaulieu Y, Marik PE. Bedside ultrasonography in the ICU: part 2. Chest. 2005 Sep;128(3):1766-81. doi: 10.1378/chest.128.3.1766.</citation>
    <PMID>16162786</PMID>
  </reference>
  <reference>
    <citation>Matamis D, Soilemezi E, Tsagourias M, Akoumianaki E, Dimassi S, Boroli F, Richard JC, Brochard L. Sonographic evaluation of the diaphragm in critically ill patients. Technique and clinical applications. Intensive Care Med. 2013 May;39(5):801-10. doi: 10.1007/s00134-013-2823-1. Epub 2013 Jan 24.</citation>
    <PMID>23344830</PMID>
  </reference>
  <reference>
    <citation>Goligher EC, Laghi F, Detsky ME, Farias P, Murray A, Brace D, Brochard LJ, Bolz SS, Rubenfeld GD, Kavanagh BP, Ferguson ND. Measuring diaphragm thickness with ultrasound in mechanically ventilated patients: feasibility, reproducibility and validity. Intensive Care Med. 2015 Apr;41(4):734. doi: 10.1007/s00134-015-3724-2. No abstract available.</citation>
    <PMID>25749574</PMID>
  </reference>
  <reference>
    <citation>MacIntyre NR, Cook DJ, Ely EW Jr, Epstein SK, Fink JB, Heffner JE, Hess D, Hubmayer RD, Scheinhorn DJ; American College of Chest Physicians; American Association for Respiratory Care; American College of Critical Care Medicine. Evidence-based guidelines for weaning and discontinuing ventilatory support: a collective task force facilitated by the American College of Chest Physicians; the American Association for Respiratory Care; and the American College of Critical Care Medicine. Chest. 2001 Dec;120(6 Suppl):375S-95S. doi: 10.1378/chest.120.6_suppl.375s. No abstract available.</citation>
    <PMID>11742959</PMID>
  </reference>
  <reference>
    <citation>MILIC-EMILI J, MEAD J, TURNER JM, GLAUSER EM. IMPROVED TECHNIQUE FOR ESTIMATING PLEURAL PRESSURE FROM ESOPHAGEAL BALLOONS. J Appl Physiol. 1964 Mar;19:207-11. doi: 10.1152/jappl.1964.19.2.207. No abstract available.</citation>
    <PMID>14155283</PMID>
  </reference>
  <reference>
    <citation>Baydur A, Behrakis PK, Zin WA, Jaeger M, Milic-Emili J. A simple method for assessing the validity of the esophageal balloon technique. Am Rev Respir Dis. 1982 Nov;126(5):788-91. doi: 10.1164/arrd.1982.126.5.788.</citation>
    <PMID>7149443</PMID>
  </reference>
  <reference>
    <citation>Bellemare F, Grassino A. Effect of pressure and timing of contraction on human diaphragm fatigue. J Appl Physiol Respir Environ Exerc Physiol. 1982 Nov;53(5):1190-5. doi: 10.1152/jappl.1982.53.5.1190.</citation>
    <PMID>7174413</PMID>
  </reference>
  <reference>
    <citation>Grinnan DC, Truwit JD. Clinical review: respiratory mechanics in spontaneous and assisted ventilation. Crit Care. 2005 Oct 5;9(5):472-84. doi: 10.1186/cc3516. Epub 2005 Apr 18.</citation>
    <PMID>16277736</PMID>
  </reference>
  <reference>
    <citation>Vivier E, Mekontso Dessap A, Dimassi S, Vargas F, Lyazidi A, Thille AW, Brochard L. Diaphragm ultrasonography to estimate the work of breathing during non-invasive ventilation. Intensive Care Med. 2012 May;38(5):796-803. doi: 10.1007/s00134-012-2547-7. Epub 2012 Apr 5.</citation>
    <PMID>22476448</PMID>
  </reference>
  <reference>
    <citation>Yang KL, Tobin MJ. A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med. 1991 May 23;324(21):1445-50. doi: 10.1056/NEJM199105233242101.</citation>
    <PMID>2023603</PMID>
  </reference>
  <reference>
    <citation>Nemer SN, Barbas CS, Caldeira JB, Guimaraes B, Azeredo LM, Gago R, Souza PC. Evaluation of maximal inspiratory pressure, tracheal airway occlusion pressure, and its ratio in the weaning outcome. J Crit Care. 2009 Sep;24(3):441-6. doi: 10.1016/j.jcrc.2009.01.007. Epub 2009 Mar 27.</citation>
    <PMID>19327955</PMID>
  </reference>
  <verification_date>January 2019</verification_date>
  <study_first_submitted>December 22, 2018</study_first_submitted>
  <study_first_submitted_qc>January 11, 2019</study_first_submitted_qc>
  <study_first_posted type="Actual">January 14, 2019</study_first_posted>
  <last_update_submitted>January 11, 2019</last_update_submitted>
  <last_update_submitted_qc>January 11, 2019</last_update_submitted_qc>
  <last_update_posted type="Actual">January 14, 2019</last_update_posted>
  <responsible_party>
    <responsible_party_type>Principal Investigator</responsible_party_type>
    <investigator_affiliation>University of Thessaly</investigator_affiliation>
    <investigator_full_name>DEMOSTHENES MAKRIS</investigator_full_name>
    <investigator_title>Associate Professor of Critical Care Medicine</investigator_title>
  </responsible_party>
  <condition_browse>
    <!-- CAUTION:  The following MeSH terms are assigned with an imperfect algorithm            -->
    <mesh_term>Respiratory Insufficiency</mesh_term>
    <mesh_term>Respiratory Paralysis</mesh_term>
    <mesh_term>Paralysis</mesh_term>
  </condition_browse>
  <patient_data>
    <sharing_ipd>No</sharing_ipd>
  </patient_data>
  <!-- Results have not yet been posted for this study                                          -->
</clinical_study>


download date: ClinicalTrials.gov processed this data on September 20, 2023
link text: Link to the current ClinicalTrials.gov record.
url: https://clinicaltrials.gov/ct2/show/NCT03802383
org study id: 3531/29.06.2018
nct id: NCT03802383
lead sponsor: 
has dmc: No
is fda regulated drug: No
is fda regulated device: No
Through this study the investigators aim to clarify the relationship between
      trans-diaphragmatic pressure and various parameters of the diaphragmatic contraction
      evaluated by ultrasound. The following parameters will be studied: esophageal pressure,
      gastric pressure, diaphragm thickness at peak inspiration (Tdi,pi), diaphragm thickness at
      end expiration (Tdi,ee), diaphragm thickening (Tdi,pi - Tdi,ee), diaphragm thickness fraction
      [TFdi=(Tdi,pi - Tdi,ee)/Tdi,ee], diaphragm excursion (Di,e), Maximal Inspiratory pressure
      (M.I.P), Pressure-Time product of the trans-diaphragmatic pressure (PΤPdi),Tension Time
      Diaphragm Index (T.T.Di) and the rapid shallow breathing index (R.S.B.I.). These measurements
      will be made in two phases.Firstly, during the spontaneous breathing trial and secondly
      during spontaneous breathing through an airway of reduced diameter.Furthermore, during the
      M.I.P. test the aforementioned ultrasound parameters will be measured. The aim of this study
      is to discover new means of a successful prediction of weaning in the first 48 hours
      following extubation.
Protocol

      The patients will enter a Spontaneous Breathing Trial (S.B.T.) for sixty minutes. During the
      S.B.T. the desirable measurements will be made: transdiaphragmatic pressure, diaphragm
      thickening, Tdi,pi , Tdi,ee , TFdi, Di,e, Maximal Inspiratory Pressure (M.I.P.) , Rapid
      Shallow Breathing Index (R.S.B.I.). If the S.B.T. is successful then the patient will be
      removed from the mechanical ventilator. For the next 48 hours the patient will be monitored
      for distress signs and thus be reintubated or if the weaning of the patient was successful
      extubation.

      Flow chart of the study

        1. The patient meets the S.B.T. criteria.

        2. The patient is placed in a semi recumbent position.

        3. A nasogastric tube attached with two balloons, which are connected with a pressure
           transducer, one placed in the stomach and the other one in the lower third of the
           esophagus.

        4. The balloons will be connected with a Hans Rudolph pneumotachograph for the measurement
           of the tidal volume, the flow and the esophageal pressure.

        5. An occlusion test will be performed to make sure the esophageal balloon is correctly
           placed.

        6. Measurement of Pes, Pgas, M.I.P., and simultaneous sonographic measurements (Diaphragm
           thickening,Tdi,pi, Tdi,ee, Di,e,TFdi) during the S.B.T. with the patient being in
           t-tube.

        7. Measurement of the same parameters during an S.B.T. with an airway of reduced diameter.

        8. The patient will be reintubated for 60 minutes.

        9. The S.B.T. is repeated and the R.S.B.I. will be calculated.

       10. If the S.B.T. is successful according to the R.S.B.I. the patient will be disconnected
           from the mechanical ventilation.

       11. Monitoring of the patient for the next 48 hours, for the extubation respiratory distress
           syndrome or reintubation for another reason.

       12. Further monitoring for 30 days in order to measure the time spent in mechanical
           ventilation

      Definitions

      Transdiaphragmatic pressure

      Pdi will be measured with the use of a nasogastric catheter which has 2 balloons attached at
      25 cm and 10 cm from it's distal end. The balloons, of 7 cm length, will be connected with a
      pressure transducer and with the use of a linear pneumotachometer Hans Rudolph RSS 100HR the
      graphic representation of the pressures will be displayed in a computer monitor. The balloons
      will contain 0,5-1 ml of air and will be placed in the stomach and the lower third of the
      esophagus. To ensure the correct positioning of the balloons an occlusion test (Baydur test)
      will be performed ,where the similar fluctuations between the esophageal and the airway
      pressure will be affirmative. As long as the stomach balloon is concerned the positive
      pressures during the inspiration will be affirmative of the correct positioning.

      Pressure Time Index

      P.T.I. is the product of the ratio of the mean inspiratory pressure to the maximal
      inspiratory pressure (Pavg/Mip) and the ratio of the inspiratory time to the total duration
      of the inspiratory cycle (Ti/Ttot).The usefulness of the P.T.I. consists that it measures the
      total energy cost of breathing.

      P.T.I.=(Pavg/M.I.P.)x(Ti/Ttot) where as a Pavg is considered the airway pressure in the
      middle of the inspiratory phase (ti/2).

      Tension Time Diaphragm Index

      Ttdi is used as an index of diaphragmatic exhaustion. Measurements above 0,15 are indicative
      of the diaphragmatic incapability to maintain spontaneous breathing for more than 45 minutes,
      whence the naming of Ttdi critical

      Ttdi = (Pdi/Pdi,max)x(TixTtot)

      Rapid Shallow Breathing Index

      Rapid Shallow Breathing Index (R.S.B.I.) is a method used for predicting the weaning outcome.
      It is measured during spontaneous breathing and equates to the ratio of respiratory rate per
      minute (RR) to the tidal volume (Vt) expressed in liters.

      R.S.B.I. = RR/Vt

      It has been shown that an R.S.B.I. values below 105 breaths/min/L can predict a successful
      weaning.

      Maximal Inspiratory Pressure

      Maximal Inspiratory Pressure (M.I.P.) is used as a predictive factor of the weaning outcome.
      It is measured with a manometer placed in a fully occluded airway, while the patient tries to
      breathe through it for 20 seconds. The highest pressure value is named M.I.P. It has been
      shown that values below -25 cmH2O are indicative of a positive weaning outcome.

      Diaphragm Ultrasound

      The diaphragmatic function is assessed during spontaneous breathing and during breathing with
      an airway of reduced diameter. The diaphragmatic movement is assessed with ultrasound
      (Phillips iE33) using a Linear 3-11 MHz head. The ultrasound probe is placed in the mid
      axillary line perpendicular to the zone of apposition between the 8th-10th intercostal
      spaces. In this position, the diaphragm is shown as a non-echogenic layer between two
      echogenic layers which represent the diaphragmatic pleura and the abdominal peritoneum. With
      this technique the diaphragmatic thickening (Tdi,pi - Tdi,ee), diaphragmatic thickness at
      end-expiration (Tdi,ee) and end-inspiration (Tdi,pi), diaphragmatic excursion Di,e and
      diaphragmatic thickening fraction TFdi are measured. All the measurements are made using
      M-Mode Sonography.
observational model: Cohort
time perspective: Prospective
measure: The correlation of inspiratory esophageal pressure, as assessed by esophageal manometry, to diaphragmatic thickness, as assessed by ultrasound, in patients who are weaned from mechanical ventilation.
time frame: 1 year
description: The authors will study the correlation of inspiratory esophageal pressure, as assessed by esophageal manometry (values in cm H2O), to diaphragmatic thickness, as assessed by ultrasound (values in cm), in patients who are weaned from mechanical ventilation.Then a comparison will be made between the patients who failed and those who succeeded. Ten consecutive tidal breaths will be studied both by esophageal manometry and ultrasound of the diaphragm in each patient.
study pop: 
sampling method: Probability Sample
criteria: 
gender: All
minimum age: 18 Years
maximum age: N/A
healthy volunteers: No
last name: Demosthenes Makris
phone: +306943706079
email: appollon7@hotmail.com
last name: APOSTOLOS-ALKIVIADIS MENIS
email: menis.ap.alk@gmail.com
facility: 
status: Recruiting
contact: 
country: Greece
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PMID: 27334266
citation: Turnbull D, Webber S, Hamnegard CH, Mills GH. Intra-abdominal pressure measurement: validation of intragastric pressure as a measure of intra-abdominal pressure. Br J Anaesth. 2007 May;98(5):628-34. doi: 10.1093/bja/aem060.
PMID: 17456490
citation: Beaulieu Y, Marik PE. Bedside ultrasonography in the ICU: part 1. Chest. 2005 Aug;128(2):881-95. doi: 10.1378/chest.128.2.881.
PMID: 16100182
citation: Beaulieu Y, Marik PE. Bedside ultrasonography in the ICU: part 2. Chest. 2005 Sep;128(3):1766-81. doi: 10.1378/chest.128.3.1766.
PMID: 16162786
citation: Matamis D, Soilemezi E, Tsagourias M, Akoumianaki E, Dimassi S, Boroli F, Richard JC, Brochard L. Sonographic evaluation of the diaphragm in critically ill patients. Technique and clinical applications. Intensive Care Med. 2013 May;39(5):801-10. doi: 10.1007/s00134-013-2823-1. Epub 2013 Jan 24.
PMID: 23344830
citation: Goligher EC, Laghi F, Detsky ME, Farias P, Murray A, Brace D, Brochard LJ, Bolz SS, Rubenfeld GD, Kavanagh BP, Ferguson ND. Measuring diaphragm thickness with ultrasound in mechanically ventilated patients: feasibility, reproducibility and validity. Intensive Care Med. 2015 Apr;41(4):734. doi: 10.1007/s00134-015-3724-2. No abstract available.
PMID: 25749574
citation: MacIntyre NR, Cook DJ, Ely EW Jr, Epstein SK, Fink JB, Heffner JE, Hess D, Hubmayer RD, Scheinhorn DJ; American College of Chest Physicians; American Association for Respiratory Care; American College of Critical Care Medicine. Evidence-based guidelines for weaning and discontinuing ventilatory support: a collective task force facilitated by the American College of Chest Physicians; the American Association for Respiratory Care; and the American College of Critical Care Medicine. Chest. 2001 Dec;120(6 Suppl):375S-95S. doi: 10.1378/chest.120.6_suppl.375s. No abstract available.
PMID: 11742959
citation: MILIC-EMILI J, MEAD J, TURNER JM, GLAUSER EM. IMPROVED TECHNIQUE FOR ESTIMATING PLEURAL PRESSURE FROM ESOPHAGEAL BALLOONS. J Appl Physiol. 1964 Mar;19:207-11. doi: 10.1152/jappl.1964.19.2.207. No abstract available.
PMID: 14155283
citation: Baydur A, Behrakis PK, Zin WA, Jaeger M, Milic-Emili J. A simple method for assessing the validity of the esophageal balloon technique. Am Rev Respir Dis. 1982 Nov;126(5):788-91. doi: 10.1164/arrd.1982.126.5.788.
PMID: 7149443
citation: Bellemare F, Grassino A. Effect of pressure and timing of contraction on human diaphragm fatigue. J Appl Physiol Respir Environ Exerc Physiol. 1982 Nov;53(5):1190-5. doi: 10.1152/jappl.1982.53.5.1190.
PMID: 7174413
citation: Grinnan DC, Truwit JD. Clinical review: respiratory mechanics in spontaneous and assisted ventilation. Crit Care. 2005 Oct 5;9(5):472-84. doi: 10.1186/cc3516. Epub 2005 Apr 18.
PMID: 16277736
citation: Vivier E, Mekontso Dessap A, Dimassi S, Vargas F, Lyazidi A, Thille AW, Brochard L. Diaphragm ultrasonography to estimate the work of breathing during non-invasive ventilation. Intensive Care Med. 2012 May;38(5):796-803. doi: 10.1007/s00134-012-2547-7. Epub 2012 Apr 5.
PMID: 22476448
citation: Yang KL, Tobin MJ. A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. N Engl J Med. 1991 May 23;324(21):1445-50. doi: 10.1056/NEJM199105233242101.
PMID: 2023603
citation: Nemer SN, Barbas CS, Caldeira JB, Guimaraes B, Azeredo LM, Gago R, Souza PC. Evaluation of maximal inspiratory pressure, tracheal airway occlusion pressure, and its ratio in the weaning outcome. J Crit Care. 2009 Sep;24(3):441-6. doi: 10.1016/j.jcrc.2009.01.007. Epub 2009 Mar 27.
PMID: 19327955
responsible party type: Principal Investigator
investigator affiliation: University of Thessaly
investigator full name: DEMOSTHENES MAKRIS
investigator title: Associate Professor of Critical Care Medicine
mesh term: Respiratory Insufficiency
mesh term: Respiratory Paralysis
mesh term: Paralysis
sharing ipd: No