The Role of Oxygen Reserve Index (ORi) in Apneic Ventilation

Ankara City Hospital

Status: Not yet enrolling

Conditions: Ventilation; Apnea; Body Mass Index; Oxygen Reserve Index

Treatments: Other: OXYGEN RESERVE INDEX

Study type: Observational

Funder types: Other

Identifiers

NCT07119866

Oxygen Reserve Index

Details and patient eligibility

About

Background: The Oxygen Reserve Index (ORI) is a non-invasive parameter utilizing multi-wavelength pulse co-oximetry. ORI can provide early warnings of deteriorating oxygenation before changes are reflected in SpO₂ levels. This study aimed to investigate the feasibility of non-ventilated intubation in patients undergoing cholecystectomy as a means to achieve safe intubation without nasogastric tube placement, with reduced trauma and cost, and improved time efficiency.

Full description

Obesity is a complex and chronic disease that significantly impacts respiratory physiology. It leads to increased work of breathing and reduced compliance of the chest wall. In morbidly obese individuals, there is a marked reduction in total lung capacity, vital capacity, forced expiratory volume in one second (FEV1), and forced vital capacity (FVC). Additionally, due to their elevated metabolic demands, these patients exhibit higher oxygen consumption rates.

The Oxygen Reserve Index (ORi) (Masimo Corp., Irvine, CA, USA) is an advanced, continuous, and non-invasive parameter that provides a relative indication of arterial partial pressure of oxygen (PaO₂).

ORI monitoring can be particularly beneficial in patients at risk for inadequate preoxygenation, those with difficult mask ventilation, hypoxemic patients with aspiration risk, rapid sequence induction scenarios, obese individuals, ICU intubations, and invasive ventilation cases. It has also been shown to provide early warnings of desaturation in select patient groups, contributing to improved patient safety.

Enrollment: 60 estimated patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 18-60 years
• ASA 1-2
• Mallampati score <2
• Scheduled for elective laparoscopic cholecystectomy under general anesthesia

Exclusion criteria

• <18 and >60 years
• ASA 3-4
• Initial ORI value below 0.24

Trial design

60 participants in 2 patient groups

ORI>0.24

Description:

Patients, aged between 18 and 60 years, classified as ASA physical status I-II,and with a Mallampati score \<2, were enrolled.On the day of surgery, following identity verification and confirmation of the surgical site, patients were positioned on a warmed operating table.Standard monitoring was applied, including ECG, SBP and DBP, SpO₂, and the ORI.Preoxygenation was achieved by administering 100% oxygen via 8 deep breaths over 60 seconds.When the ORI value reached 0.4, intravenous anesthesia induction was initiated using propofol 2 mg/kg, fentanyl 2 mcg/kg, and rocuronium 0.6mg/kg.During muscle relaxation, patients were not ventilated via mask.The ORI value at the time of induction and at the 2nd minute post-induction was recorded.If the ORI dropped below 0.24 before the 2-minute mark, mask ventilation was initiated, and the time of intervention was noted.Endotracheal intubation was then performed using a standard,atraumatic technique after achieving adequate muscle relaxation.

Treatment:

Other: OXYGEN RESERVE INDEX

ORI<0.24

Description:

Patients, aged between 18 and 60 years, classified as ASA physical status I-II,and with a Mallampati score \<2, were enrolled.On the day of surgery, following identity verification and confirmation of the surgical site, patients were positioned on a warmed operating table.Standard monitoring was applied, including ECG, SBP and DBP, SpO₂, and the ORI.Preoxygenation was achieved by administering 100% oxygen via 8 deep breaths over 60 seconds.When the ORI value reached 0.4, intravenous anesthesia induction was initiated using propofol 2 mg/kg, fentanyl 2 mcg/kg, and rocuronium 0.6mg/kg.During muscle relaxation, patients were not ventilated via mask.The ORI value at the time of induction and at the 2nd minute post-induction was recorded.If the ORI dropped below 0.24 before the 2-minute mark, mask ventilation was initiated, and the time of intervention was noted.Endotracheal intubation was then performed using a standard,atraumatic technique after achieving adequate muscle relaxation.

Treatment:

Other: OXYGEN RESERVE INDEX