Comparison of the Effects of High, Low and Minimal Flow Anesthesia Managements on ORI and Partial Oxygen Pressure

Continuous ORI Monitoring is a Non-invasive Monitoring Method

The aim of our study is to show that continuous oxygen reserve index monitoring is a non-invasive monitoring method that can be used as a supporting parameter to PaO2 in blood gas in hypoxia and hyperoxia monitoring when different fresh gas flow is used in general anesthesia.

Study Overview

• Status: Completed
• Conditions: General Anesthetic
• Intervention / Treatment: Device: Masimo Radical-7 Pulse CO-Oximeter

Detailed Description

Ninety patients included in the study were classified into three groups. After the high flow period, FGF and inspired oxygen fraction (FiO2) was set to be 4 L/m and 40% in group H (high flow), 1 L/m and 50% in group L (low flow) and 0.5 L/m and 68% in group M (minimal flow), respectively.

Patients were transferred into the operating room, monitored and premedication with 0.03 mg/kg of midazolam was administered. Subsequently, the right radial artery was cannulated under local anesthesia and basal blood samples were taken. After preoxygenation (100% O2, 6 L/min, 3 min.), anesthesia induction was performed with intravenous administration of 40-60 mg lidocaine, 2 mg/kg propofol, 0.6 mg/kg rocuronium and 1.5 mcg/kg fentanyl. Patients were ventilated in volume-controlled mode (Dräger Perseus® A500 Anaesthesia Workstation, Dräger, Germany) that allows continuous monitorization of airway pressure, exhaled gas volume, FiO2, volatile anesthetic substance concentration, and CO2 concentration within the scope of the Common European Standard EN 740. Medical air was used as the carrier gas. End-tidal carbon dioxide (EtCO2) was continuously monitored after intubation, and tidal volume and ventilation rates were adjusted to maintain EtCO2 at 30-40 mmHg. In maintenance, general anesthesia was provided in all three groups by inhalation of remifentanil 0.05-0.2 mcg/kg/min and FGF 4 L/min 50% oxygen-medical air mixture with 6-8% desflurane. After intubation, 6% desflurane was administered with a fresh gas flow of 4 L/min for 10 minutes in all three groups, and the MAC value was adjusted to 1.

Thereafter, oxygen 1 L/min, and medical air 3 L/min (FGF 4 L/min, FiO2 40%) were administered to patients in group H for high-flow anesthesia; oxygen 0.37 L/min, medical air 0.63 L/min (FGF 1 L/min, FiO2 50%) to patients in group L for low-flow anesthesia; oxygen 0.3 L/min and medical air 0.2 L/min (FGF 0.5 L/min, FiO2 68%) to patients in group M under minimal flow anesthesia. After reaching adequate MAC values after 10 minutes of intubation, FiO2 was reduced to 40% in Group H, keeping the FGF unchanged; in Group L fresh gas flow was reduced to 1 L/min, in Group M fresh gas flow was reduced to 0.5 L/min, and the scale setting of desflurane was adjusted in order to achieve MAC 1 for the remainder of the surgery.

A disposable sensor (RD Rainbow Lite Set ORI Probe, Masimo Corp. Irvine CA), shielded from light, was placed on the left index finger to record the data displayed with Masimo Radical 7 pulse CO-Oximeter (Masimo Corp. Irvine CA).

At the end of the surgical procedure in all patients, the vaporizer was turned off and high FGF (4 L/min, FiO2 100%) was applied to ensure rapid removal of the anesthetic gases from the lungs, and manual ventilation was started. Sugammadex (2-4 mg/kg iv.) was administered to reverse the residual muscle relaxation at the end of the operation in patients who did not experience complications during the operation, and after spontaneous breathing was achieved, the patients were extubated in the operating room.

• Study Type: Observational
• Enrollment (Actual): 90

Contacts and Locations

Study Locations

• Turkey
  • Samsun, Turkey, 55090
    • Samsun Research and Education Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

ASA II and III patients aged between 18-75 years, who were scheduled to undergo elective open abdominal surgery lasting <60 minutes under general anesthesia

Description

Inclusion Criteria:

• ASA II and III patients,
• Aged between 18-75 years,
• who were scheduled to undergo elective open abdominal surgery lasting <60 minutes under general anesthesia

Exclusion Criteria:

• refusal of consent to study inclusion by the patient or his/her guardian,
• inability to use the sensor due to finger deformation or hypoperfusion,
• having a history of malignant hyperthermia,
• presence of clinically significant anemia, morbid obesity, alcohol or drug addiction, having a severe cardiac, renal or hepatic impairment,
• having a history of cerebrovascular disease,
• being a pregnant or presently lactating and having local anesthetic or opioid sensitivity

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
minimal flow; For minimal-flow anesthesia, oxygen 0.3 L/min and medical air 0.2 L/min (FGF 0.5 L/min, FiO2 68%) were administered to patients in group M.	Device: Masimo Radical-7 Pulse CO-Oximeter; The Masimo Radical-7 Pulse CO-Oximeter is a device for the measurement of pulse oximetry, oxygen reserve index (ORi), perfusion index (PI), and pleth variability index (PVI). The device is the product of a company called Masimo Inc, Irvine, CA, USA
low flow; For low-flow anesthesia, oxygen 0.37 L/min and medical air 0.63 L/min (FGF 1 L/min, FiO2 50%) were administered to patients in group L.	Device: Masimo Radical-7 Pulse CO-Oximeter; The Masimo Radical-7 Pulse CO-Oximeter is a device for the measurement of pulse oximetry, oxygen reserve index (ORi), perfusion index (PI), and pleth variability index (PVI). The device is the product of a company called Masimo Inc, Irvine, CA, USA
high flow; For high-flow anesthesia, oxygen 1 L/min and medical air 3 L/min (FGF 4 L/min, FiO2 40%) were administered to patients in group H.	Device: Masimo Radical-7 Pulse CO-Oximeter; The Masimo Radical-7 Pulse CO-Oximeter is a device for the measurement of pulse oximetry, oxygen reserve index (ORi), perfusion index (PI), and pleth variability index (PVI). The device is the product of a company called Masimo Inc, Irvine, CA, USA

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The use of continuous ORI monitoring as a supporting parameter to PaO2 in blood gasses during hypoxia and hyperoxia	To show that continuous ORI monitoring is non-invasive monitoring that can be used as a supporting parameter for PaO2 in blood gas in hypoxia and hyperoxia monitoring when different fresh gas flows (4, 1, 0.5 L/min) are used in general anesthesia practice.	intraoperative period

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The use of continuous ORI monitoring as a supporting parameter to PaO2 in blood gasses during hypoxia and hyperoxia	Parameters were recorded at nine time frames: T1 (5 minutes before anesthesia induction), T2 (after intubation), T3 (at the start of 0.5-1-4 L/min), T4 (at the 10th minute of low flow), T5 (at the 30th minute of low flow), T6 (at the 60th minute of low flow), T7 (at the 90th minute of low flow), T8 (at the 120th minute of low flow), T9 (at the end of the surgery, ventilation with 100% oxygen) and T10 (5 min after extubation).	İntraoperative period

Collaborators and Investigators

• Sponsor: Samsun Education and Research Hospital
• Investigators: Study Chair: Zahide Doganay, Professor, Samsun Research and Education Hospital

Publications and helpful links

General Publications

• Baxter AD. Low and minimal flow inhalational anaesthesia. Can J Anaesth. 1997 Jun;44(6):643-52; quiz 652-3. doi: 10.1007/BF03015449.
• Vos JJ, Willems CH, van Amsterdam K, van den Berg JP, Spanjersberg R, Struys MMRF, Scheeren TWL. Oxygen Reserve Index: Validation of a New Variable. Anesth Analg. 2019 Aug;129(2):409-415. doi: 10.1213/ANE.0000000000003706.
• Scheeren TWL, Belda FJ, Perel A. The oxygen reserve index (ORI): a new tool to monitor oxygen therapy. J Clin Monit Comput. 2018 Jun;32(3):379-389. doi: 10.1007/s10877-017-0049-4. Epub 2017 Aug 8. Erratum In: J Clin Monit Comput. 2018 Feb 14;:

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2020
• Primary Completion (Actual): June 1, 2020
• Study Completion (Actual): September 1, 2020

Study Registration Dates

• First Submitted: April 7, 2022
• First Submitted That Met QC Criteria: April 7, 2022
• First Posted (Actual): April 14, 2022

Study Record Updates

• Last Update Posted (Actual): April 22, 2022
• Last Update Submitted That Met QC Criteria: April 14, 2022
• Last Verified: April 1, 2022

More Information

Terms related to this study

• Keywords: low flow anesthesia; oxygen reserve index; arterial oxygen pressure
• Other Study ID Numbers: KAEK-2020/1/1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Our data and statistical analysis of each investigated all parameter and data are available after the publication of the clinical study
• IPD Sharing Time Frame: The data will be available after the publication of our data upon request from the researchers.
• IPD Sharing Access Criteria: There is no internet website to obtain data but the researchers can contact Dr. Naci Murat, Ondokuz Mayis University, Samsun, Turkey.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No