Effect of Positive End Expiratory Pressure at the Time of Induction in Morbidly Obese Patients

Study Overview
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Brief Summary
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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
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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: Just after inflation of cuff of endotracheal tube 5 minutes post intubation 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)

Official Title
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Single Minute of Positive End Expiratory Pressure at the Time of Induction: Effect on Arterial Blood Gases and Hemodynamics in Morbidly Obese Patients Undergoing Laparoscopic Bariatric Surgery

Conditions
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Morbid Obesity

Intervention / Treatment
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* Other: positive end expiratory pressure (PEEP)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients recruited were Anesthesia society of Anesthesiologist (ASA) physical status l, II or III, Aged 20-65 years BMI > 40kg/m2 scheduled for elective laparoscopic bariatric surgery Exclusion Criteria: Patients who denied consent Did not fulfill the inclusion criteria, patients undergoing Emergency and/or open surgery Patients requiring more than 2 attempts for intubation

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 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
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Zero PEEP<br>This group of patients did not receive any PEEP at the time of induction of general anesthesia (n= 30) | |
| Experimental: PEEP- 10 cm of H2O<br>This group comprised of patients who received a PEEP of 10 cm H2O at the time of induction of general anesthesia (n= 30) | Other: positive end expiratory pressure (PEEP)<br>* Positive end expiratory pressure was applied using anesthesia machine at the time of induction in the patients undergoing laparoscopic bariatric surgery<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial oxygenation (PaO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP preoperatively just before taking the patient in operation theater | Arterial oxygenation (PaO2) in mm Hg recorded preoperatively and taken as baseline value | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction of general anesthesia | Arterial carbon di oxide (PaCO2) values in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP preoperatively just before taking the patient in operation theater | Arterial carbon di oxide (PaCO2) in mm Hg was recorded from ABG preoperatively and taken as baseline value | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction of general anesthesia | Pulse Rate (beats/ min) was recorded and compared between group receiving PEEP and group not receiving PEEP preoperatively just before taking the patient in operation theater | Pulse Rate (beats/ min) was recorded from ABG preoperatively and taken as baseline value | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction of general anesthesia | Systolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP preoperatively just before taking the patient in operation theater | Systolic BP in mm Hg was recorded from ABG preoperatively and taken as baseline value | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction of general anesthesia | Diastolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP preoperatively just before taking the patient in operation theater | Diastolic BP in mm Hg was recorded from ABG preoperatively and taken as baseline value | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial oxygenation (PaO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP just after the placement and cuff inflation of endotracheal tube | Arterial oxygenation (PaO2) in mm Hg was recorded just after the placement and cuff inflation of endotracheal tube | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial carbon di oxide (PaCO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP just after the placement and cuff inflation of endotracheal tube | Arterial carbon di oxide (PaCO2) in mm Hg was recorded just after the placement and cuff inflation of endotracheal tube | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Pulse rate (beats/ min) was recorded and compared between group receiving PEEP and group not receiving PEEP just after the placement and cuff inflation of endotracheal tube | Pulse rate (beats/ min) was recorded just after the placement and cuff inflation of endotracheal tube | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Systolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP just after the placement and cuff inflation of endotracheal tube | Systolic BP in mm Hg was recorded just after the placement and cuff inflation of endotracheal tube | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Diastolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP just after the placement and cuff inflation of endotracheal tube | Diastolic BP in mm Hg was recorded just after the placement and cuff inflation of endotracheal tube | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial oxygenation (PaO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP five minutes after intubation | Arterial oxygenation (PaO2) in mm Hg was recorded five minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial carbon di oxide (PaCO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP five minutes after intubation | Arterial carbon di oxide (PaCO2) in mm Hg was recorded five minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Pulse rate (beats/ min) was recorded and compared between group receiving PEEP and group not receiving PEEP five minutes after intubation | Pulse rate (beats/ min) was recorded five minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Systolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP five minutes after intubation | Systolic BP in mm Hg was recorded five minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Diastolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP five minutes after intubation | Diastolic BP in mm Hg was recorded five minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial oxygenation (PaO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP ten minutes after intubation | Arterial oxygenation (PaO2) in mm Hg was recorded ten minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Arterial carbon di oxide (PaCO2) in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP ten minutes after intubation | Arterial carbon di oxide (PaCO2) in mm Hg was recorded ten minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Pulse rate (beats/ min) was recorded and compared between group receiving PEEP and group not receiving PEEP ten minutes after intubation | pulse Rate (beats/ min) was recorded ten minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Systolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP ten minutes after intubation | Systolic BP in mm Hg was recorded ten minutes post intubation | 
| effect of PEEP of 10 cm H2O on arterial blood gases and hemodynamic parameters, when applied at the time of induction | Diastolic BP in mm Hg was recorded and compared between group receiving PEEP and group not receiving PEEP ten minutes after intubation | Diastolic BP in mm Hg was recorded ten minutes post intubation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Preoperative arterial oxygenation was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded preoperatively and taken as baseline value | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Preoperative arterial carbon di oxide was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded preoperatively and taken as baseline value | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Preoperative pulse rate was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded preoperatively and taken as baseline value | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Systolic blood pressure was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded preoperatively and taken as baseline value | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Diastolic blood pressure was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded preoperatively and taken as baseline value | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Arterial oxygenation recorded just after the placement and cuff inflation of endotracheal tube, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded just after the placement and cuff inflation of endotracheal tube | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Arterial carbon di oxide (mm Hg) recorded just after the placement and cuff inflation of endotracheal tube, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded just after the placement and cuff inflation of endotracheal tube | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Pulse rate (beats/ min) recorded just after the placement and cuff inflation of endotracheal tube, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameters was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded just after the placement and cuff inflation of endotracheal tube | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Systolic pressure(mm Hg) recorded just after the placement and cuff inflation of endotracheal tube, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded just after the placement and cuff inflation of endotracheal tube | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Diastolic blood pressure(mm Hg) recorded just after the placement and cuff inflation of endotracheal tube, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded just after the placement and cuff inflation of endotracheal tube | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Arterial oxygenation recorded five minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded five minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Arterial carbon di oxide (mm Hg) recorded five minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded five minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Pulse rate (beats/ min) recorded five minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded five minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Systolic pressure(mm Hg) recorded five minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded five minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Diastolic blood pressure(mm Hg) recorded five minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded five minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Arterial oxygenation (mm Hg) recorded ten minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded ten minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Arterial carbon di oxide (mm Hg) recorded ten minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded ten minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Pulse rate (beats/ min) recorded ten minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded ten minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Systolic blood pressure (mm Hg) recorded ten minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded ten minutes post intubation | 
| Effect of pulmonary artery systolic pressure (PASP) on the efficacy of PEEP as reflected by changes in ABG and hemodynamic parameters | Diastolic blood pressure(mm Hg) recorded ten minutes after intubation, was compared of those patients who received PEEP and had PASP ≤ 30 mm Hg with those patients who did not receive PEEP and had PASP ≤ 30 mm Hg. Similarly the above parameter was compared in patients with PASP > 30 mm Hg receiving PEEP with those not receiving any PEEP | ABG and hemodynamic parameters were recorded ten minutes post intubation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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morbidly obese, Pulmonary artery systolic pressure, Positive end expiratory pressure, laparoscopic bariatric surgery