Volume-Controlled Ventilation and Pressure-Controlled Ventilation Volume Guaranteed in Obese Patients in Laparoscopic-Assisted Surgery

Study Overview
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Brief Summary
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The aim of this study is to compare the efficacy of the pressure controlled ventilation volume-guaranteed (PCV-VG) versus volume-controlled ventilation (VCV) modes as regards lung compliance and oxygenation index in obese patients undergoing laparoscopic assisted surgery especially in Trendelenburg position.

Detailed Description
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Obesity, defined as a Body Mass Index (BMI) >30 kg.m-2, is characterized by increased airway resistance, labored breathing and decreased respiratory system compliance. An increased rate of obese patients undergoing laparoscopic assisted surgery (LAS) is a health care concern due to anesthesia and ventilation difficulties in the obese population. Therefore, understanding the physiology and pathophysiology of lung function is an important issue during long-lasting LAS. Carbon dioxide pneumoperitoneum with steep Trendelenburg positioning leads to a cranial displacement of the diaphragm and an increased volume of atelectasis, with a consequent decrease of total lung volume, lung compliance, and functional residual capacity. Thus, alleviation of increased airway pressure, improvement in oxygenation and CO2 elimination are the main goals during anesthetic management in laparoscopic assisted surgery. In pressure controlled ventilation volume-guaranteed (PCV-VG) mode, the ventilator regulates the Peak Inspiratory Pressure (PIP) to achieve the optimal TV. To achieve the target volume, ventilator parameters are regularly changed without adjusting airway pressures. Hence, PCV-VG has the advantages of both Volume-Controlled Ventilation (VCV) and pressure controlled ventilation (PCV) to preserve the target minute ventilation while maintaining a low incidence of barotraumas. PCV-VG is a type-controlled ventilation mode with a dual character as it has the criteria of both PCV and VCV. This recent ventilation mode which is one of the pressure regulated volume controlled (PRVC) that include Auto Flow ventilation, offers the ability to reduce the inspiratory pressure and as a result the incidence of barotrauma

Official Title
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Comparative Study Between the Effect of Volume-Controlled Ventilation and Pressure-Controlled Ventilation Volume Guaranteed in Obese Patients in Laparoscopic Assisted Surgery

Conditions
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Obese, Volume-Controlled Ventilation, Pressure-Controlled Ventilation Volume Guaranteed, Laparoscopy

Intervention / Treatment
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* Other: Pressure controlled ventilation-volume guaranteed
* Other: Volume controlled ventilation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age: 16 - 60 years old. Sex: both males and females. Undergoing elective Laparoscopic Surgery. Obese patient with Body Mass Index between ≥30 Kg/m2. American society of Anesthesiologist (ASA) class I/ II. Exclusion Criteria: Patient refusal. American society of Anesthesiology (ASA) III or IV. Intraoperative hemodynamic instability. Patients with pulmonary hypertension. Obese patients on home O2 therapy Pneumoperitoneum with CO2 with intra-abdominal pressure exceeding 15mmHg. Anti-Trendelenburg position. Asthmatic Patients. Patients with advanced liver disease. Patients with advanced renal disease. Patients with advanced malignancy. Pregnant females.

Ages Eligible for Study
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Minimum Age: 16 Years
Maximum Age: 60 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group (PCV-VG): Pressure controlled ventilation-volume guaranteed<br>Patients will receive pressure controlled ventilation-volume guaranteed | Other: Pressure controlled ventilation-volume guaranteed<br>* Respiratory parameters will be set as: actual tidal volume 8 mL/kg actual body weight, respiratory rate 12 breaths/min, PEEP of five mmHg, oxygen flow 1 L/min, fraction inspired oxygen (FiO2) 0.6, and I:E ratio of 1:2. Respiratory parameters will be kept constant if ETCO2 is <45 mmHg. When ETCO2 exceed 45 mmHg, respiratory rate or tidal volume will be adjusted to maintain ETCO2 below 45 mmHg.<br>|
| Other: Group (VCV): Volume controlled ventilation<br>Patients will receive Volume controlled ventilation | Other: Volume controlled ventilation<br>* Respiratory parameters will be set as: actual tidal volume 8 mL/kg actual body weight, respiratory rate 12 breaths/min, PEEP of five mmHg, oxygen flow 1 L/min, fraction inspired oxygen (FiO2) 0.6, and I:E ratio of 1:2. Respiratory parameters will be kept constant if ETCO2 is <45 mmHg. When ETCO2 exceed 45 mmHg, respiratory rate or tidal volume will be adjusted to maintain ETCO2 below 45 mmHg.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxygenation index | Oxygenation index =mean airway pressure × fraction of inspired oxygen (FiO2) × 100÷ Partial pressure of oxygen (PaO2) | Till the end of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean arterial blood pressure | Mean arterial blood pressure (MAP) will be monitored 10 minutes before anesthesia induction , immediately before onset of pneumoperitoneum, every 10 minutes in the first hour, and at the end of surgery. | Till the end of surgery | 
| Heart rate | Heart rate (HR) will be monitored 10 minutes before anesthesia induction , immediately before onset of pneumoperitoneum, every 10 minutes in the first hour, and at the end of surgery. | Till the end of surgery | 
| Oxygen saturation SpO2 | Oxygen saturation SpO2 will be monitored 10 minutes before anesthesia induction , immediately before onset of pneumoperitoneum, every 10 minutes in the first hour, and at the end of surgery. | Till the end of surgery | 
| Arterial PCo2 | Arterial blood gases will be analyzed using a blood gas analyzer before anesthesia induction and every 10 minutes in the first hour for arterial oxygen tension (paO2) , arterial CO2 tension (paCO2). | Till the end of surgery | 
| Lung compliance | Lung mechanics readings included peak air way pressure (Ppeak), plateau pressure (Pplat), mean airway pressure (Pmean), dynamic and static compliance of the respiratory system will be recorded after intubation and every 10 minutes in the first hour | Till the end of surgery |