Effect of Positive End Expiratory Pressure at the Time of Induction in Morbidly Obese Patients
Condition: Morbid Obesity
MeSH terms: Obesity, Morbid
Study type: Interventional

Summary: 
      Background: Positive end expiratory pressure (PEEP) at the time of induction increases
      oxygenation by preventing lung atelectasis. However, PEEP may not prove beneficial in all
      cases. Factors affecting the action of PEEP have not been elucidated well and remain
      controversial. Pulmonary vasculature has direct bearing on the action of PEEP as has been
      proven in previous studies. Thus this study was planned to evaluate the action of PEEP on the
      basis of pulmonary artery systolic pressure (PASP) which is non invasive and easily measured
      by trans-thoracic echocardiography.

      Methodology: This Randomized prospective study comprised of 70 morbidly obese patients, ASA
      grade II or III, aged 20-65 years with BMI > 40kg/m2, scheduled for elective laparoscopic
      bariatric surgery. Ten patients had to be excluded. Thus a total of 60 patients participated
      in the study. Thirty patients received no PEEP at the time of induction while other 30
      patients were given a PEEP of 10cm of H2O. Serial ABG samples were taken pre operatively, at
      the time of intubation, 5 min after intubation and 10 min after intubation. Patients were
      then divided into four groups on the basis of PASP value of ≤ 30 mm Hg with and without PEEP
      or > 30 mm Hg
    

Detailed description: 
      This prospective study was conducted in the Department Of Anaesthesiology& Critical Care, Sri
      Aurobindo Institute of Medical Sciences & P.G. Institute and Mohak Hospitals, Indore, over a
      period of one year. Seventy morbidly obese patients, ASA grade II or III, aged 20-65 years
      with BMI > 40kg/m2, scheduled for elective laparoscopic bariatric surgery were selected and a
      written informed consent was obtained. All the recruited patients underwent 2D-trans-thoracic
      echocardiography and PASP was recorded. Echocardiography was performed by same cardiologist
      as this measurement is operator dependent. Patients who denied consent, those undergoing
      Emergency and/or open surgery and those requiring more than 2 attempts for intubation were
      excluded.

      Arterial line was inserted pre operatively and ABG sample was taken and hemodynamic parameter
      recording done while the patient was breathing room air. Both groups were pre-oxygenated for
      3 minutes with 100% Oxygen. Standard procedure was used for induction of anesthesia in all
      the patients. No premedication was given. All the patients were induced with i.v.
      Glycopyrolate (0.005-0.01 mg/kg), i.v. Fentanyl (2µg/kg) and i.v. Propofol. Once the patient
      became unresponsive to verbal commands, Succinylcholine was then administered in a dose of 1-
      1.5 mg/ kg. Mechanical ventilation was started with 100% oxygen. A PEEP of 10 cm H2O was
      applied using four hand technique in Study group while the control group received no PEEP.
      After one minute endotracheal intubation was done. PEEP was continued in study group after
      intubation.

      Arterial blood gas (ABG) analysis and hemodynamic parameters were recorded at following
      stages:

        1. Just after inflation of cuff of endotracheal tube

        2. 5 minutes post intubation

        3. 10 minutes post intubation

      Patients were then again divided into four groups on the basis of PASP:

      Group 1: Patients with PASP ≤ 30 mmHg receiving no PEEP (n= 11) Group 2: PASP ≤ 30 mm Hg
      receiving PEEP of 10 cm H2O (n= 11) Group 3: PASP > 30 mm Hg receiving no PEEP (n= 19) Group
      4: PASP > 30 mm Hg receiving PEEP of 10 cm H2O (n=19)
    

Intervention name(s): positive end expiratory pressure (PEEP)
Intervention type(s): Other
Intervention description(s): Positive end expiratory pressure was applied using anesthesia machine at the time of induction in the patients undergoing laparoscopic bariatric surgery
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: Pulmonary artery systolic pressure; Positive end expiratory pressure; morbidly obese; laparoscopic bariatric surgery