Electrical Impedance Tomography Measurements During Apnea Test in Patients With Suspected Brain Death

Apnea testing is the final decisive examination in the strictly regulated process of brain death assessment. There is no standardized method found in the literature for apnea testing except for the inspection of possible spontaneous chest movements. In addition, the test itself lasts for several minutes leading to the collapse of the lungs.

Electrical impedance tomography (EIT) is a non-invasive, real-time monitoring technique, which is suitable for detecting changes in lung volumes during ventilation. With its help, one can examine the spontaneous initiation of inspiration, the development of atelectasis and the reopening of collapsed regions by mechanical ventilation.

Furthermore, the apnea test provides for analysing the effect of changes in pulmonary perfusion on impedance in the absence of noise generated by ventilation.

Study Overview

• Status: Completed
• Conditions: Brain Death
• Intervention / Treatment: Diagnostic test: Apnea test, alveolar recruitment

Detailed Description

The aim of the study is to assess the eligibility of electrical impedance monitoring for the detection of possible spontaneous initiations of inspiration during apnea test in patients with suspected brain death. The study could contribute to the opening of new areas in the clinical use of the electrical impedance device. An additional aim is to observe the collapse and the reopening by recruitment manoeuvers of different pulmonary regions.

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Hungary
  • Szeged, Hungary, 6725
    • University of Szeged

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 99 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients with suspected brain death undergoing apnea test for detecting the absence of spontaneous breathing

Exclusion Criteria:

• age under 18
• pregnancy
• pulmonectomy, lung resection in the past medical history
• clinically end stage chronic obstructive pulmonary disease (COPD)
• severe hemodynamic instability (vasopressor refractory shock)
• severe bullous emphysema and/or spontaneous pneumothorax in the past medical history
• chest drainage in situ due to pneumothorax and/or bronchopleural fistula

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: apnea test, recruitment manoeuvre; Continuous electric impedance tomography (EIT) recording. Recording of initial vital parameters and arterial blood gas results. Adjusment of PaCO2 between 38-42 mmHg, 10 minutes of preoxygenation with FiO2 of 1.0 then disconnection of the patient from the ventilator.; Continuous administration of 6 L/min O2 flow via a catheter into the tracheal tube.; Arterial blood gas sampling and recording of vital parameters in every second minutes. Detection of any spontaneous respiratory movement by the apnoe test investigator or by EIT signals.; Reconnection with respirator if there is any sign of spontaneous breathing effort or if there is no spontaneous breathing effort and the PaCO2 is over 60 mmHg. Recording of vital parameters.; Recruitment manoeuvre (PEEP 20 cmH2O, pressure control 20 cmH20 for 40 minutes) then set up of the initial ventilator parameters.; Terminal arterial blood gas results and vital parameters 5 minutes following the end of the recruitment manoeuvre.

Diagnostic test: Apnea test, alveolar recruitment; Alveolar recruitment following the phase of apnea testing

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
detection of spontaneous inspiration	Detection of absolute changes in impedance using EIT during apnea test, which may refer to spontaneous initiations of inspiration	20 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gas exchange	Change in arterial partial pressure of oxygen (PaO2) (mmHg) following alveolar recruitment performed after apnea testing	20 minutes
Dynamic compliance	Change in dynamic compliance (ml/cmH2O) following alveolar recruitment	20 minutes
End expiratory lung impedance	Change in end expiratory lung impedance (EELI) (%) following alveolar recruitment	20 minutes
Center of ventilation	Change in center of ventilation (%) following alveolar recruitment	20 minutes
Lung perfusion	Changes in lung perfusion during the apnea phase (%)	20 minutes

Collaborators and Investigators

• Sponsor: Kiskunhalas Semmelweis Hospital the Teaching Hospital of the University of Szeged
• Collaborators: Szeged University; Budapest University of Technology and Economics; Hochschule Furtwangen University

Study record dates

Study Major Dates

• Study Start (Actual): April 1, 2021
• Primary Completion (Actual): April 13, 2023
• Study Completion (Actual): April 13, 2023

Study Registration Dates

• First Submitted: April 22, 2021
• First Submitted That Met QC Criteria: April 22, 2021
• First Posted (Actual): April 23, 2021

Study Record Updates

• Last Update Posted (Actual): February 20, 2024
• Last Update Submitted That Met QC Criteria: February 18, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Keywords: Electrical Impedance Tomography; Apnea testing
• Additional Relevant MeSH Terms: Pathologic Processes; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Neurobehavioral Manifestations; Unconsciousness; Consciousness Disorders; Coma; Death; Brain Death
• Other Study ID Numbers: apnEIT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No