Low Flow Anesthesia in Morbid Obesity

July 10, 2020 updated by: Evrim Kucur Tulubas, Bakirkoy Dr. Sadi Konuk Research and Training Hospital

Does Low Flow Anesthesia Protect Lung Functions in Laparoscopic Sleeve Gastrectomy?

In this study to planned to research the efficacy of low-flow anesthesia on patients undergoing sleeve gastrectomy due to morbid obesity on respiratory functions after surgery by examining FEV1 and FVC values and FEV1/FVC ratio.

Study Overview

Detailed Description

Morbid obese patients undergoing sleeve gastrectomy due to morbid obesity after 01.01.2019 will be randomly divided into 2 groups with controls. To prevent selection bias in the study, numbers will be produced at random. The produced numbers will be determined as 0: control and 1: experiment groups and patients will be divided into groups as such. Random numbers will be generated by the MedCalc 18.2.1. program (MedCalc Statistical Software MedCalc Software bvba, Ostend, Belgium; http://www.medcalc.org; 2018). Group 1 is determined as patients to be administered high-flow anesthesia, while Group 2 will be administered low-flow anesthesia. After anesthesia induction, Group 1 will have 4 liters/minute (50% O2 50%) flow administered, while patients in Group 2 will have 1 liter/minute (50% O2, 50% air) flow administered. The study included adult patients who signed the voluntary consent form aged from 18-65 years, American Society of Anesthesiologists (ASA) III, and body mass index (BMI) >40. Inclusion criteria for the study are no alcohol or drug addiction or diagnosis of chronic obstructive pulmonary disease (COPD) during routine preoperative assessment by chest diseases, FEV1/FVC ratio, FEV1 and FVC values within normal limits and no previous abdominal surgery.

Those with stop-bang score below 4 will be included in the study. On the day of surgery, all patients had FEV1, FVC value and FEV1/FVC ratio examined by a single anesthesia technician using a manual RST device without the knowledge of the anesthesia expert.

Pressure tests and calibration of the anesthesia device is performed each morning for every surgery. After calibration the mechanical ventilator alarm limits for ins O2 are lower limit 40%, EtCO2 35-45 mmHg, min Vol (tidal volume in 1 min x frequency) according to the patient ± 0.5. After patient is placed on the operating table in ramp position, all patients are monitored with triple route ECG, pulse oximetry and pressure cuff. The clinical protocol for all patients undergoing sleeve gastrectomy includes BIS (bispectral index) and TOF (train of four) monitoring. Before beginning induction, first 3 mg midazolam and fentanyl 150 mvq IV were administered. According to ideal weight and BIS score for 40-60, 2-5 mg propofol and 0.5 mg rocuronium according to true weight were administered. Patients were ventilated with 6 L/min 60% O2 for 2 minutes. Patients were endotracheally intubated with a Macintosh laryngoscope. In addition to assessment of respiratory sounds linked to obesity with auscultation, EtCO2 capnography was used to confirm the efficacy of intubation. After intubation 50 mg ranitidine and 8 mg ondansetron were routinely administered. Fixing the remifentanil dose to 0.1 mcg/kg/min, infusion was administered. Sevoflurane percentage was changed to ensure MAC (minimum alveolar concentration of 0.6-1.1 for BIS score of 40-60 for maintenance. During ventilation in PRVC mode, Group 1 had 4 liter/minute (50% O2, 50% air) flow administered, while Group 2 had 3 L/min 4% for Sevoflurane the first 3 minutes as wash-in. Then flow was administered at 1 L/min (50% O2, 50% air). According to ideal weight, mechanical ventilator settings were 6-10 ml tidal volume, frequency 12/min (increasing, if necessary, for etCO2 35-45 mmHg), PEEP 5-10 cm/H2O and inspirium/expirium ratio ½. In Group 1, sevoflurane percentage was set to correlate with BIS monitoring. In Group 2, after intubation the sevoflurane percentage was set to a higher percentage to reach the desired MAC value. Every 5 minutes during surgery, MAC, BIS, mean arterial pressure, peak heart rate, sPO2, etCO2, inSO2, frequency and PEEP values were recorded. In Group 2, 5 minutes before the end of surgery, flow was increased from 1 L to 4 L for wash-out. Both groups had remifentanil ended 10 minutes before the end of surgery. Later 1 g paracetamol and 100 mg tramadol IV were administered. Five minutes before the end of the operation patient-controlled SIMV+VE mode with trigger setting of 6 was organized. At the end of surgery, patients were administered 2 mg/kg sugammadex according to ideal weight. When the patients trigger setting reaches muscle power it was lowered to zero. When trigger is zero and there is sufficient tidal volume to reach TOF (train of four) value >90% and BIS score is 80-100, patients were extubated. They were sent to the recovery room. In recovery the ARISCAT risk index was calculated. Later when modified Aldrete scoring system is ≥9, patients were sent to the ward.

After surgery, mobilization and respiratory physiotherapy were provided in the 2nd hour. Vital signs including mean arterial pressure (MAP) were recorded in the postoperative period with 20 mg tenoxicam I.V. administered in the 1st hour. The PCA device was set with tramadol 300 mg/100 ml, bolus 10 mg, lock time 12 minutes without basal infusion. Patients with numeric rating scale (NRS) scores ≥4 had a rescue dose of 4 mg morphine I.V. administered. Each patient began oral intake (water) in the postoperative 24th hour, with early mobilization. A second dose of tenoxicam I.V. was administered in the postoperative 8th hour.

In the 24th hour postoperative, patients had analgesia to ensure VAS score is below 4, with RFT repeated by the same doctor who performed RFT preoperatively.

Study Type

Interventional

Enrollment (Actual)

100

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Istanbul, Turkey
        • Bakırköy Dr. Sadi Konuk Trainig And Research Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • american Society of Anesthesiologists (ASA) III
  • body mass index (BMI) >40.
  • FEV1/FVC ratio within normal limits
  • FEV1 and FVC values within normal limits
  • those with stop-bang score below 4

Exclusion criteria:

  • alcohol abuse
  • drug abuse
  • previous abdominal surgery.
  • chronic obstructive pulmonary disease (COPD)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: TREATMENT
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: DOUBLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
OTHER: high-flow anesthesia
Before beginning induction, first 3 mg midazolam and fentanyl 150 mvq IV were administered. According to ideal weight and BIS score for 40-60, 2-5 mg propofol and 0.5 mg rocuronium according to true weight were administered. After intubation 50 mg ranitidine and 8 mg ondansetron were routinely administered. Fixing the remifentanil dose to 0.1 mcg/kg/min, infusion was administered. Group 1 had 4 liter/minute (50% O2, 50% air) flow administered. Mechanical ventilator settings were 6-10 ml tidal volume, frequency 12/min (increasing, if necessary, for etCO2 35-45 mmHg), PEEP 5-10 cm/H2O and inspirium/expirium ratio ½. Both groups had remifentanil ended 10 minutes before the end of surgery. Later 1 g paracetamol and 100 mg tramadol IV were administered.
Group 2 had 4 liter/minute (50% O2, 50% air) flow administered.
Other Names:
  • Procedure/Anesthesia
OTHER: low-flow anesthesia
Before beginning induction, first 3 mg midazolam and fentanyl 150 mvq IV were administered. According to ideal weight and BIS score for 40-60, 2-5 mg propofol and 0.5 mg rocuronium according to true weight were administered. After intubation 50 mg ranitidine and 8 mg ondansetron were routinely administered. Fixing the remifentanil dose to 0.1 mcg/kg/min, infusion was administered. Group 2 had 1 liter/minute (50% O2, 50% air) flow administered. Mechanical ventilator settings were 6-10 ml tidal volume, frequency 12/min (increasing, if necessary, for etCO2 35-45 mmHg), PEEP 5-10 cm/H2O and inspirium/expirium ratio ½. Both groups had remifentanil ended 10 minutes before the end of surgery. Later 1 g paracetamol and 100 mg tramadol IV were administered.
Group 1 had 1 liter/minute (50% O2, 50% air) flow administered.
Other Names:
  • Procedure/Anesthesia

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pulmonary Function Test Results
Time Frame: Preoperative 1st hour and postoperative 24th hours
FEV1/FVC (%) ratio in hundred morbid obese patients who will undergo laparoscopic sleeve gastrectomy under low flow and high flow anesthesia will be measured
Preoperative 1st hour and postoperative 24th hours

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Length of hospital stay
Time Frame: Up to 72th hours
Length of hospital stay (days) of hundred morbid obese patients who will undergo laparoscopic sleeve gastrectomy under low flow and high flow anesthesia will be measured.
Up to 72th hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Evrim Kucur Tulubas, Dr

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ACTUAL)

January 10, 2019

Primary Completion (ACTUAL)

March 10, 2020

Study Completion (ACTUAL)

April 10, 2020

Study Registration Dates

First Submitted

February 21, 2019

First Submitted That Met QC Criteria

April 10, 2019

First Posted (ACTUAL)

April 12, 2019

Study Record Updates

Last Update Posted (ACTUAL)

July 13, 2020

Last Update Submitted That Met QC Criteria

July 10, 2020

Last Verified

July 1, 2020

More Information

Terms related to this study

Other Study ID Numbers

  • Obesity Surgery FEV1/FVC
  • Evrim Kucur Tulubas (OTHER: Bakirkoy Dr. Sadi Konuk Training and Research Hospital)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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