Clinical trial NCT03505632: High Versus Low Positive End Expiratory Pressure With Alveolar Recruitment Maneuver in Laparoscopic Bariatric Surgeries
Official title: Low Positive End Expiratory Pressure With Alveolar Recruitment Maneveurs Versus High Positive End Expiratory Pressure as Lung Protective Strategy in Laparoscopic Bariatric Surgeries
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Anesthesia
Lead sponsor: Mansoura University
Sponsor class: OTHER
First posted: 2018-04-23
Enrollment: 60
Sex: ALL
Minimum age (years): 20
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Mechanical ventilation with either recruitment maneuver and low PEEP versus conventional mechanical ventilation and high PEEP
Primary purpose: SUPPORTIVE_CARE

Brief summary: For the patients undergoing laparoscopic bariatric surgery, application of low (PEEP) with frequent alveolar recruitment maneuver could be beneficial and superior to conventional ventilation with a high (PEEP) in improving lung compliance, better oxygenation and less dead space .This hypothesis could be achieved by minimizing the expected lung atelectasis during anesthesia for this particular kind of laparoscopic surgery without any haemodynamics alterations.This trial was designed to study the effects of alveolar recruitment strategy with low PEEP versus conventional mechanical ventilation with higher PEEP on the patients undergoing laparoscopic bariatric surgeries. The primary end point of the study will be the achievement of the highest dynamic lung compliance (Cdyn). Improvement of intraoperative oxygenation (Pao2/Fio2) and achievement of a lower dead space ratio (vd/vt), with stable intraoperative haemodynamics will be considered as secondary outcome

Detailed description: The use of a alveolar recruitment maneuver(RM) effectively increases end expiratory lung volume and reopens lung atelectasis during anesthesia and reproduces better oxygenation for surgical obese patients .Alveolar recruitment maneuver with PEEP could decreases atelectasis and improved oxygenation in obese surgical patients .This concept indicate that the maintenance of low PEEP after multiple alveolar recruitment maneuver during anesthesia may improve its benefits without complications. Patients will randomly divided by computerized randomization sequence method into two groups (30 patients in each study group):

Both groups receive volume controlled ventilation, tidal volume was 6-8 ml/kg for predicted body weight. The PBW calculated according to a formula: 50 + 0.91 × {height (cm)-152.4} for men and 45.5 + 0.91 × {height (cm) - 152.4} for women. The respiratory rate was adjusted to keep the EtCO2= 35-40 mmHg. The inspiratory to expiratory ratio (I:E ratio) was 1:2 and the FiO2 was 0.40.

Low PEEP+RM group: Patients receive PEEP of 5cmH2O. Recruitment maneuver ( RM) will be done by increasing the PEEP in stepwise manner. First PEEP was increased to 10 cmH2O (3 breaths),then to 15 cm H2O (3 breaths).Finally, PEEP was raised to 20 cmH2O (10 breaths).Then decreased for 15cmH2O for (3 breaths),10cmH2O for(3 breaths), and finally returned back to original PEEP 5 cmH2O.The total procedure took 2 min. Recruitment will be carried out at the following times: post intubation(T1) , after peritoneal insuflation(T2) ,after desuflation (T3) and before extubation(T4) . The peak airway pressure should not exceed 40cmH2O.

High PEEP group: Patients receive throughout ventilation 15 cm H2O PEEP with maintaining the peak airway pressure below 40 cm H2O.

Monitoring :after intubation(T1), post-insufflation(T2), after disinflation (T3) and before extubation(T4) for the fillowoing.1--Minute volume ,respiratory rate and tidal volume 2-Arterial blood gas( PaO2, PaCO2,pH).3-Hemodynamics : heart rate and invasive arterial blood pressure.4-Calculated dynamic Lung compliance by equation: T V/peak airway pressure- PEEP .5-calculated driving pressure by equation: Pplat-PEEP.6-Calculated dead space ratio (VD/VT) by equation :PaCO2-ETCO2)/ PaCO2.

Rescue strategies:

A) Intraoperative hypoxemia (SpO2≤92%): In both groups ,rescue primarily will be performed by an increase in FiO2 by 0.1 till reaching oxygen (100% ) .If failed and hypoxia persist a recruitment maneuver will be carried out with stepwise incremental PEEP irrespective of the group allocation.

The time of the event of hypoxia and its management will be recorded.

B) Intraoperative hypotension (systolic blood pressure \<90 mmHg):

1. Abort any recruitment maneuver in low PEEP+ RM group.
2. Gradual decrease PEEP by 5 cmH2O in stepwise manner in higher PEEP group.
3. Give 500 ml bolus colloid and correct fluid status with blood transfusion if indicated.
4. Noradrenalin infusion as last resort

Eligibility criteria: Inclusion Criteria:

1. American Society of Anesthesiologists (ASA) physical status II and III.
2. Patients included in the study having body mass index ≥35kg/m2.
3. Both genders.
4. Age ≥ 20 years old.

Exclusion Criteria:

1. Major cardiovascular diseases (heart failure and ejection fraction below 40%).
2. Sever obstructive pulmonary diseases (FEV1 \< 50 and FVC \< 50)
3. Hepatic and renal impairment.
4. Younger than 20 years old.

Primary outcomes:
measure: Dynamic lung compliance
timeFrame: During intra-operative mechanical ventilation
Secondary outcomes:
measure: Horowitz ratio
timeFrame: During mechanical ventilation
measure: Alveolar dead space ratio
timeFrame: During mechanical ventilation
measure: Systolic blood pressure
timeFrame: During mechanical ventilation
measure: Diastolic blood pressure
timeFrame: During mechanical ventilation
measure: Mean blood pressure
timeFrame: During mechanical ventilation
measure: Heart rate
timeFrame: During mechanical ventilation
measure: Analgesia
timeFrame: postoperative time for 24 hours
measure: Atelectasis
timeFrame: postoperative time for 24 hours
Other outcomes:
Locations:
city: Mansourah
country: Egypt
facility: Mansoura faculty of medicine
state: Dakahlia
Study officials:
affiliation: Mansoura University
name: Amgad A Zaghloul, MD
role: STUDY_CHAIR
affiliation: Mansoura University
name: Ahmed M Farid, MD
role: STUDY_CHAIR
References: