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

Not Applicable

Completed

• Conditions: Obesity

• Registration Number: NCT04627883
• Lead Sponsor: General Hospital of Ningxia Medical University

Brief Summary

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.

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 Timeline

• Study Start: 2020-08-17
• Status Verified: 2020-10
• Study First Submitted: 2020-10-11
• Study First Submitted QC: 2020-11-08
• Study First Posted: 2020-11-13
• Primary Completion: 2022-01-01
• Study Completion: 2022-01-01
• Last Update Submitted: 2025-02-13
• Last Update Posted: 2025-02-17

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 40

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Safe Apnea Time	The arterial saturation as measured by pulse oximetry remained at or above 93% after endotracheal intubation immediately.	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% .

Secondary Outcome Measures

Name	Time	Method
EtO2	After 5 minutes of noninvasive positive pressure ventilation	Fractional concentration of oxygen in end-tidal gas

Trial Locations

Locations (1)

General Hospital of Ningxia Medical University; 🇨🇳 Yinchuan, Ningxia, China