Clinical trial NCT04976504: Early Warning for Desaturation by Oxygen Reserve Index
Official title: Early Warning for Desaturation by Oxygen Reserve Index During Induction of General Anesthesia
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Desaturation of Blood
Anesthesia
Keywords: Oxygen reserve index
Induction of general anesthesia
Lead sponsor: Taipei Veterans General Hospital, Taiwan
Sponsor class: OTHER_GOV
First posted: 2021-07-26
Enrollment: 25
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Male and female patients aged 18 to 80 years with ASA physical status I to III scheduled for elective surgery with planned arterial catheter placement before induction of general anesthesia and did not match the exclusion criteria.

Brief summary: During the induction of general anesthesia, the anesthesiologist needs to provide the oxygen supply to meet the patient's needs continuously. In the clinical scenario, the pulse oximeter is used as a standard to monitor hemoglobin oxygen saturation (SpO2) but is limited to assess the oxygenation status beyond the measurement of 100%. The Oxygen Reserve Index (ORi) is a dimensionless parameter between 0 and 1 that is related to real-time oxygenation reserve status. This study was designed to evaluate the duration of warning time for desaturation provided by different ORi alarm triggers during prolonged apnea in surgical patients. The primary endpoint was the duration of additional warning time provided by the ORi trigger. The secondary endpoint was the correlation of ORi and PaO2.

Detailed description: This is an observational study of the routine clinical practice with no specific additional interventions required.

The investigators enrolled the American Society of Anesthesiologists (ASA) physical status I to III patients scheduled for elective surgery with planned arterial catheter placement before induction. Patients were positioned supine on the operating room table. Standard monitors and the ORi sensor were placed. The patients were preoxygenated with a facemask (flow rate of 8 to 10 liters/minute) for 3 minutes with spontaneous ventilation. Propofol (2-2.5 mg/kg), fentanyl (2-3 mcg/kg) and rocuronium (0.6-0.9 mg/kg) were administrated to achieve anesthesia induction during following 3 minutes. The patient was keeping ventilated manually by the anesthesiologist during the induction phase and intubated under direct visualization with a video-assisted laryngoscope at 6 minutes. The endotracheal tube was not connected to the breathing circuit to avoid apneic oxygenation. The patients remained apneic. Ventilation was resumed when SpO2 fell to 90%. ORi and SpO2 were recorded every ten seconds. Arterial blood is sampled every minute, from preoxygenation to resumed ventilation, to observe blood oxygen concentration changes.

Eligibility criteria: Inclusion Criteria:

* Male and female patients aged 18 to 80 years with ASA physical status I to III scheduled for elective surgery with planned arterial catheter placement before induction of general anesthesia.

Exclusion Criteria:

* Age \<18 years
* Inability to give primary consent
* Pregnancy
* History of chronic obstructive pulmonary disease (COPD)
* History of asthma
* Suspected difficult intubation
* Preoperative hemoglobin less than 10 mg/dl.

Primary outcomes:
measure: Additional warning time provided by ORi trigger
timeFrame: From time of starting preoxygenation until the time of SpO2 90%, assessed up to 20 minutes
Secondary outcomes:
measure: Correlation between ORi and PaO2
timeFrame: From time of starting preoxygenation until the time of SpO2 90%, assessed up to 20 minutes
Other outcomes:
Locations:
city: Taipei
country: Taiwan
facility: Department of Anesthesiology, Taipei Veterans General Hospital
Study officials:
affiliation: Taipei Veteran General Hospital, Taiwan
name: Hung-Wei Cheng, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Applegate RL 2nd, Dorotta IL, Wells B, Juma D, Applegate PM. The Relationship Between Oxygen Reserve Index and Arterial Partial Pressure of Oxygen During Surgery. Anesth Analg. 2016 Sep;123(3):626-33. doi: 10.1213/ANE.0000000000001262.
citation: 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.
citation: Szmuk P, Steiner JW, Olomu PN, Ploski RP, Sessler DI, Ezri T. Oxygen Reserve Index: A Novel Noninvasive Measure of Oxygen Reserve--A Pilot Study. Anesthesiology. 2016 Apr;124(4):779-84. doi: 10.1097/ALN.0000000000001009.
citation: Fleming NW, Singh A, Lee L, Applegate RL 2nd. Oxygen Reserve Index: Utility as an Early Warning for Desaturation in High-Risk Surgical Patients. Anesth Analg. 2021 Mar 1;132(3):770-776. doi: 10.1213/ANE.0000000000005109.
citation: Cheng HW, Yeh CY, Chang MY, Ting CK, Chang PL. How early warning with the Oxygen Reserve Index (ORi) can improve the detection of desaturation during induction of general anesthesia? J Clin Monit Comput. 2022 Oct;36(5):1379-1385. doi: 10.1007/s10877-021-00776-z. Epub 2021 Dec 25.