Effect of Inverse Ratio Ventilation During Induction of General Anesthesia on Safe Apnea Time in Obese Patients

Effect of Inverse Ratio Ventilation During Induction of General Anesthesia on Safe Apnea Time in Obese Patients:A Randomized Controlled Trial

The purpose of this study is to investigate the clinical application value of inverse ratio ventilation in obese patients during induction of general anesthesia by studying the effect of inverse ratio ventilation on the safe apnea time.

Study Overview

• Status: Completed
• Conditions: Obesity
• Intervention / Treatment: Other: Inspiratory-to-expiratory (I : E) ratio of 1:2; Other: Inspiratory-to-expiratory (I : E) ratio of 2:1

Detailed Description

Inverse ratio ventilation(IRV) can produce mean airway pressure(Pmean)similar to external positive end expiratory pressure(Peep) by increasing inspiratory time. Moreover, the increase of Pmean was not accompanied by the further increase of peak airway pressure (Ppeak) and airway plateau pressure (Pplat), while the application of external peep accompanied with the increase of Pplat increased the risk of barotrauma . High level of Peep increased cardiac load and decreased cardiac output. A number of studies have found that the hemodynamic stability of patients can be achieved when IRV regulates the inspiratory / expiratory ratio in an appropriate range (I: E < 2:1). Therefore, the inverse ratio is considered to be superior to Peep in terms of gas exchange and respiratory mechanics.

• Study Type: Interventional
• Enrollment (Actual): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Ningxia
    • General Hospital of Ningxia Medical University, Ningxia, China, 750004
      • General Hospital of Ningxia Medical University
    • Yinchuan, Ningxia, China, 750004
      • General Hospital of Ningxia Medical University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Obese patients, aged 18-65 years, of either gender, ASA grade II-III, body mass index (BMI) > 30 kg / m2, scheduled for general anesthesia under tracheal intubation, signed informed consent.

Exclusion Criteria:

• Patients who need rapid sequence induction (RSI); patients with expected difficult airway; severe chronic respiratory diseases, such as tuberculosis, bronchitis, bronchial asthma and COPD; patients with severe cardiovascular diseases, such as severe ischemic heart disease and pulmonary hypertension; patients with severe cerebrovascular diseases, such as cerebral hemorrhage and cerebral infarction; patients with abnormal basal metabolic rate, such as pregnancy, thyrotoxicosis, pheochromocytoma; and severe stomach reflux disease; patients with abnormal hemoglobin and hematocrit.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Group 1:2; Patients in the control group had noninvasive positive pressure ventilation with inspiratory-to-expiratory (I : E) ratio of 1:2.	Other: Inspiratory-to-expiratory (I : E) ratio of 1:2; After preoxygenation and induction of anesthesia, noninvasive positive pressure ventilation with inspiratory-to-expiratory (I : E) ratio of 1:2 for 5 min before endotracheal intubation.
Other: Group 2:1; Patients in the IRV group had noninvasive positive pressure ventilation with inspiratory-to-expiratory (I : E) ratio of 2:1.	Other: Inspiratory-to-expiratory (I : E) ratio of 2:1; After preoxygenation and induction of anesthesian, noninvasive positive pressure ventilation with inspiratory-to-expiratory (I : E) ratio of 2:1 for 5 min before endotracheal intubation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safe Apnea Time	The safe apnea time was defined as that period of time during which the arterial saturation as measured by pulse oximetry remained at or above 93% .	The arterial saturation as measured by pulse oximetry remained at or above 93% after endotracheal intubation immediately.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
EtO2	Fractional concentration of oxygen in end-tidal gas	After 3 minutes of preoxygenation After 5 minutes of noninvasive positive pressure ventilation
EtO2	Fractional concentration of oxygen in end-tidal gas	After 3 minutes of noninvasive positive pressure ventilation
EtO2	Fractional concentration of oxygen in end-tidal gas	After 5 minutes of noninvasive positive pressure ventilation

Collaborators and Investigators

• Sponsor: General Hospital of Ningxia Medical University

Study record dates

Study Major Dates

• Study Start (Actual): August 17, 2020
• Primary Completion (Actual): January 1, 2022
• Study Completion (Actual): January 1, 2022

Study Registration Dates

• First Submitted: October 11, 2020
• First Submitted That Met QC Criteria: November 8, 2020
• First Posted (Actual): November 13, 2020

Study Record Updates

• Last Update Posted (Actual): March 25, 2025
• Last Update Submitted That Met QC Criteria: February 13, 2025
• Last Verified: October 1, 2020

More Information

Terms related to this study

• Keywords: inverse ratio ventilation; safe apnea time
• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Signs and Symptoms, Respiratory; Apnea
• Other Study ID Numbers: 2020-718

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

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