Investigation of Oxidative Stress in Appendectomy - Open Versus Laparoscopic in Childhood and Adolescence

Study Overview
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Brief Summary
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In the planned prospective randomized study, oxidative stress will be investigated by analyzing volatile organic compounds in the exhaled air in children. Children who have undergone open versus laparoscopic surgery for appendicitis will be compared. A better understanding of the effects of the surgical technique could be a prerequisite for an optimized surgical setting. It could also lead to recommendations for pre- or perioperatively antioxidative agents.

Detailed Description
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Aim of the study: In the planned prospective randomized study, oxidative stress will be investigated by analyzing VOCs (volatile organic compounds) in the exhaled breath in children undergoing open or laparoscopic surgery for appendicitis at the Department of Pediatric and Adolescent Surgery of the Medical University of Graz. A resulting better understanding of the effects of the surgical technique can a) be a pre-condition for an optimized surgical setting and b) possibly lead to recommendations of pre- or perioperatively antioxidatively active substances and c) be a base for future surgical procedures. Study design: This is a prospective randomized pilot study in children and adolescents undergoing surgery due to acute appendicitis. Patients with complicated appendicitis and those with an intraoperatively caused disorder will be excluded. The operation within the context of this study is exclusively conducted by specialists of the Department of Pediatric and Adolescent Surgery of the Medical University of Graz, who perform both - open and laparoscopic surgical techniques. 40 patients aged 6-18 years suffering from acute appendicitis are to be included. These are divided into 2 groups. Group 1 (n = 20) with laparoscopic and group 2 (n = 20) with open appendectomy. Recruitment and compensation of study participants: Parents/patients are made aware of the study by means of an information sheet and are provided with a declaration of consent if interested. Participants do not receive any compensation for participating in the study. Sampling of exhaled VOCs (volatile organic compounds) using NTME (needle trap microextraction) for measurement OS (oxidative stress): Number of samples: 2 samples each from exhaled breath at the times defined below (in total n = 12). The time of sampling: t1 before anaesthetic introduction (n = 2); t2 after anesthetic introduction (n = 2); t3 15 minutes after cut (n = 2); t4 30 minutes after cut (n = 2); t5 45 minutes after cut (n = 2); t6 after seam (n = 2). Analysis of exhaled VOCs for measurement OS: The exhaled breath samples taken are placed in an injector of a gas chromatograph into the inert carrier gas stream (He). The substances are assigned according to their retention time in the chromatogram and its mass spectrum. Unknown connections in the mass spectrum of exhaled breath is used as a basis for comparison with a reference database. Sampling of blood markers for measurement OS: a) sampling times for WBCs, CRP: t1 = 1 sample preoperatively (before anaesthetic introduction) and t2 = 1 sample after 24 h. b) sampling times for malondialdehyde: t1 = 1 sample before anaesthetic introduction and t2 = 1 sample after suture. Histopathological grading: The explanted vermiform appendix becomes the histopathological Refurbishment at the Institute of Pathology of the Medical University of Graz. There the classification is made according to the histopathological findings in 4 degrees of severity (acute focal appendicitis, acute suppurative appendicitis, acut gangrenous appendicitis, perforated appendicitis). Sampling WBCs, CRP: These are carried out within the scope of routine diagnostics due to the clinical presentation of the AA (acute appendicitis). Sampling VOCs: 2 breath samples are taken from each patient during expiration, taken from it. To collect the samples, the investigators use an automatic Sampling device connected directly to a capnometer. This system works with microextraction (NTME) and enables a automatic sampling of the alveolar air, i.e. in the plateau of the CO2 curve. The samples are sent to the Intitute of Rostock Medical Breath Analysis and Technologies (RoMBAT) as cooperation partner. This partner was selected because it already has extensive experience with the methodology and studies on oxidative stress during operations. Malondialdehyde (MDA) sampling: Malondialdehyde is analysed at the Clinical Institute for Medical and Chemical Laboratory Diagnostics at the Medical University of Graz means of ultra-modern GC-MS method. For this purpose, the patient is assigned to the two Measuring times 2 x 400 μl EDTA plasma taken. The second sample serves only as a safety measure if repeat measurements are necessary. The samples obtained must be deep-frozen at -80 °C within 2 hours. . Subsequently (at the latest on the following day) the samples must be analyzed to the Institute. Planned evaluation: The statistical investigations are carried out with SPSS 23.0®. Graphical representation of the data is performed with GraphPad Prism 7®. To investigate whether the main target variables (VOCs) differ in the course between the two groups, linear models are used for repeated measurements with group (open versus laparoscopic appendectomy) as intermediate subject factor and time of measurement (t1 to t6) as internal subject factor. In the case of deviations from the normal distribution, transformations are taken into consideration. The secondary targets, i.e. the changes in the serum markers on theTimes t1 and t6, are compared between the 2 groups (open versus laparoscopic appendectomy) by Mann-Whitney U-test (data not normally distributed) or independent T-test (with normal distribution). In order to establish relationships between the VOCs and the serum markers for oxidative stress at times t1 and t6 a correlation analysis is performed (depending on the data, Pearson or Spearman Rho). All statistical tests are carried out on two sides and all p-values are interpreted purely exploratively.

Official Title
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Investigation of Oxidative Stress - Open Appendectomy (OAE) Versus Laparoscopic Appendectomy (LAE) in Childhood and Adolescence - A Pilot Study

Conditions
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Appendicitis Acute

Intervention / Treatment
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* Diagnostic Test: Initial serum malondialdehyde level
* Diagnostic Test: Final serum malondialdehyde level
* Diagnostic Test: Initial differential white blood cell count
* Diagnostic Test: Final differential white blood cell count
* Diagnostic Test: Initial c-reactive protein serum level
* Diagnostic Test: Final c-reactive protein serum level
* Diagnostic Test: Initial VOC
* Diagnostic Test: VOC 5min
* Diagnostic Test: VOC 15min
* Diagnostic Test: VOC 30min
* Diagnostic Test: VOC 45min
* Diagnostic Test: Final VOC


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age from 6-18 years reliable diagnosis of acute appendicitis surgical therapy using open/laparoscopic surgical technique given approval Exclusion Criteria: Age not between 6 and 18 years chronic underlying disease/autoimmune disease complicated appendicitis (perforation, consecutive purulent peritonitis, abscess formation) infection outside acute appendicitis SIRS taking medications containing the cytochrome P450 (CYP) system affect including cortisone impaired liver function unaccepted consent

Ages Eligible for Study
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Minimum Age: 6 Years
Maximum 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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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: 40 patients aged 6-18 years suffering from acute appendicitis are to be included. These are divided into 2 groups. Group 1 (n = 20) with laparoscopic and group 2 (n = 20) with open appendectomy.
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: OAE group<br>All patients will undergo measurements of oxydative stress (initial serum malondialdehyde level and final serum malondialdehyde level), White blood cell count (initial differential white blood cell count and final differential white blood cell count), c-reactive protein measurements (initial c-reactive protein serum level and final c-reactive protein serum level) as well as volatile organic compound (VOC) sampling (initial VOC, VOC 5min, VOC 15min, VOC 30min, VOC 45min and final VOC). | Diagnostic Test: Initial serum malondialdehyde level<br>* Blood sample (0.4ml) will be obtained within 5 minutes before induction of general anaesthesia. Samples will be obtained in both groups (LAE and OAE)<br>Diagnostic Test: Final serum malondialdehyde level<br>* Blood sample (0.4ml) will be obtained within 5 minutes after wound closure. Samples will be obtained in both groups (LAE and OAE)<br>Diagnostic Test: Initial differential white blood cell count<br>* Differential blood counts (microscopic) will be obtained during pre-operative routine work-up. Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Final differential white blood cell count<br>* Differential blood counts (microscopic) will be obtained 24h after the first sample (Initial differential blood count). Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Initial c-reactive protein serum level<br>* C-reactive protein levels will be obtained during pre-operative routine work-up. Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Final c-reactive protein serum level<br>* C-reactive protein levels will be obtained 24h after the first sample (initial c-reactive protein level). Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Initial VOC<br>* Volatile organic compound sampling (2 samples within 5 minutes) within 10 minutes before induction of general anesthesia<br>Diagnostic Test: VOC 5min<br>* Volatile organic compound sampling (2 samples within5 minutes) within 5 minutes after endotracheal intubation before skin incision.<br>Diagnostic Test: VOC 15min<br>* Volatile organic compound sampling (2 samples within 5 minutes) 15 minutes after skin incision.<br>Diagnostic Test: VOC 30min<br>* Volatile organic compound sampling (2 samples within 5 minutes) 30 minutes after skin incision.<br>Diagnostic Test: VOC 45min<br>* Volatile organic compound sampling (2 samples within 5 minutes) 45 minutes after skin incision.<br>Diagnostic Test: Final VOC<br>* Volatile organic compound sampling (2 samples within 5 minutes) within 5 minutes after skin closure.<br>|
| Active Comparator: LAE group<br>All patients will undergo measurements of oxydative stress (initial serum malondialdehyde level and final serum malondialdehyde level), White blood cell count (initial differential white blood cell count and final differential white blood cell count), c-reactive protein measurements (initial c-reactive protein serum level and final c-reactive protein serum level) as well as volatile organic compound (VOC) sampling (initial VOC, VOC 5min, VOC 15min, VOC 30min, VOC 45min and final VOC). | Diagnostic Test: Initial serum malondialdehyde level<br>* Blood sample (0.4ml) will be obtained within 5 minutes before induction of general anaesthesia. Samples will be obtained in both groups (LAE and OAE)<br>Diagnostic Test: Final serum malondialdehyde level<br>* Blood sample (0.4ml) will be obtained within 5 minutes after wound closure. Samples will be obtained in both groups (LAE and OAE)<br>Diagnostic Test: Initial differential white blood cell count<br>* Differential blood counts (microscopic) will be obtained during pre-operative routine work-up. Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Final differential white blood cell count<br>* Differential blood counts (microscopic) will be obtained 24h after the first sample (Initial differential blood count). Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Initial c-reactive protein serum level<br>* C-reactive protein levels will be obtained during pre-operative routine work-up. Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Final c-reactive protein serum level<br>* C-reactive protein levels will be obtained 24h after the first sample (initial c-reactive protein level). Samples will be obtained in both groups (LAE and OAE).<br>Diagnostic Test: Initial VOC<br>* Volatile organic compound sampling (2 samples within 5 minutes) within 10 minutes before induction of general anesthesia<br>Diagnostic Test: VOC 5min<br>* Volatile organic compound sampling (2 samples within5 minutes) within 5 minutes after endotracheal intubation before skin incision.<br>Diagnostic Test: VOC 15min<br>* Volatile organic compound sampling (2 samples within 5 minutes) 15 minutes after skin incision.<br>Diagnostic Test: VOC 30min<br>* Volatile organic compound sampling (2 samples within 5 minutes) 30 minutes after skin incision.<br>Diagnostic Test: VOC 45min<br>* Volatile organic compound sampling (2 samples within 5 minutes) 45 minutes after skin incision.<br>Diagnostic Test: Final VOC<br>* Volatile organic compound sampling (2 samples within 5 minutes) within 5 minutes after skin closure.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Are volatile respiratory gas markers for oxidative stress (such as pentanes, isoprenes) dependent on the surgical method (open versus laparoscopic appendectomy)? | We investigate the respiratory volatile organic compounds before, during and at the end of surgery and compare the respiratory gas profiles of the two groups open versus laparoscopic appendectomy. | 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Alterations of serum malondialdehyde serum levels. | The changes of the serum marker for oxidative stress MDH before and after surgery will be investigated and the changes in open versus laparoscopic appendectomy will be compared. One sample will be taken preoperatively and one sample postoperatively. | 1 year | 
| Alterations of inflammation markers. | The changes of the serum inflammation markers before and after surgery will be investigated and the changes in open versus laparoscopic appendectomy will be compared. | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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acute appendicitis, volatile organic compounds, oxidative stress, laparoscopic appendectomy, open appendectomy