Change of Regional Ventilation During Spontaneous Breathing After Lung Surgery

Study Overview
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Brief Summary
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Perioperative changes in regional ventilation by pulmonary electrical impedance tomography and spirometry will be investigated in patients at risk for postoperative pulmonary complications. Those patients undergo lung and flail chest surgery.

Detailed Description
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Postoperative pulmonary complications (Defined as pulmonary infection, pleural effusion, atelectasis, pneumothorax, bronchospasm, aspiration pneumonitis or respiratory insufficiency subsequent to surgery) increase the morbidity and mortality of surgical patients. Several independent factors determined by the patients' characteristics and the operative procedure increase the risk for those complications. The postoperative decrease of values measured by spirometry, such as the forced vital capacity (FVC) and forced expiratory volume in one second (FEV1), were found in patients after major surgical procedures for several days. The postoperative reduction of those measurement can be the result of general functional limitations in those patients (e.g. by postoperative pain) or the result of a regional postoperative pulmonary complication (e.g. atelectasis, pleural effusion). The method of the electrical impedance tomography (EIT) enables to visualize the regional ventilation within a transversal section of the lung in real time. Studies examining the change of pulmonary EIT for several days postoperatively in spontaneously breathing patients are lacking. The aim of the present study is to examine perioperative changes in regional ventilation in spontaneously breathing patients during their recovery after lung and flail chest surgery. Moreover, the association of those changes with expected changes in spirometry is tested. Finally, in patients with evident postoperative pulmonary complications the value of pulmonary EIT to detect those changes is investigated. The study should improve the knowledge about the development of postoperative pulmonary complications and test the scientific and clinical value of pulmonary EIT in those spontaneously breathing patients.

Official Title
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Change of Regional Ventilation During Spontaneous Breathing After Lung Surgery

Conditions
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Pulmonary Infection, Respiratory Insufficiency, Aspiration Pneumonitis, Bronchospasm, Atelectasis

Intervention / Treatment
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* Other: Perioperative pulmonary function tests


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult Inpatient Lung surgery under general anaesthesia Exclusion Criteria: Missing informed consent Outpatient Emergency procedure Revision surgery of hospitalized patients Pneumothorax Pleural effusion Pleural effusion or pleural empyema with need to cannulate scheduled Pneumonectomy Expected hospital stay of less than three days Pregnancy Allergy against material of the electrode belt (silicone rubber, stainless steel, gold-plated brass) Injured, inflamed or otherwise affected skin within the target region of the electrode belt Unstable spine injury Body mass index of more than 50 kg/m2 Incapacity to lie quietly for the examination Pacemaker, defibrillator or other active implant Reoperation before the examination at the third postoperative day Exclusion criteria during clinical course: performed pneumonectomy Reoperation postoperative ventilation at the third day

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Lung surgery<br>26 patients (up to 36) undergoing lung surgery having an elevated risk for postoperative pulmonary complications will be examined by perioperative pulmonary function tests | Other: Perioperative pulmonary function tests<br>* Pulmonary electrical impedance tomography, spirometry, pulse oximetry and query performed preoperatively, at the the third, fifth and seventh postoperative day<br>|
| Flail chest<br>8 patients undergoing an operative stabilization of a flail chest will be examined by perioperative pulmonary function tests | Other: Perioperative pulmonary function tests<br>* Pulmonary electrical impedance tomography, spirometry, pulse oximetry and query performed preoperatively, at the the third, fifth and seventh postoperative day<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lateral Change from baseline in regional ventilation | Regional ventilation is measured by pulmonary electrical impedance tomography. The ipsi- and contralateral change in the calculated 'Center of Ventilation' is evaluated | baseline and 3. postoperative day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lateral Change from baseline in regional ventilation depending on side of surgery | Regional ventilation is measured by pulmonary electrical impedance tomography. The influence of the side of surgery on the ipsi- and contralateral change in the calculated 'Center of Ventilation' is evaluated | baseline and 3. postoperative day |