Oxygen Reserve Index (ORi) in Identifying Desaturation

Официальное название

The Role of Oxygen Reserve Index (ORi) in Identifying Early Desaturation During Endolaryngeal Surgery: A Randomized Clinical Trial

Обзор

This randomized clinical trial investigates whether Oxygen Reserve Index (ORi) monitoring enables earlier detection of impending hypoxemia compared with conventional pulse oximetry during apneic intermittent ventilation in adult patients undergoing endolaryngeal surgery under general anesthesia. By providing continuous, noninvasive assessment of oxygen reserve in the hyperoxic range, ORi may offer an earlier warning of oxygen depletion before peripheral oxygen saturation declines. The study compares time to reventilation thresholds, arterial blood gas parameters, and perioperative respiratory outcomes between ORi-guided and standard SpO₂-guided monitoring strategies.

Подробное описание

This prospective, single-center, randomized clinical trial was designed to evaluate the role of the Oxygen Reserve Index (ORi) in the early detection of hypoxemia during apneic intermittent ventilation in adult patients undergoing elective endolaryngeal surgery under general anesthesia. Endolaryngeal procedures require shared airway management and frequently involve apneic periods, during which conventional pulse oximetry may fail to provide timely warning of declining oxygen reserves due to the plateau phase of the oxyhemoglobin dissociation curve. Eligible patients aged 18 years and older with ASA physical status I-III were randomly assigned to either an ORi-monitored group or a control group monitored with standard peripheral oxygen saturation (SpO₂). All patients underwent standardized anesthesia induction, preoxygenation, and apneic intermittent ventilation. In the ORi group, the threshold for resuming ventilation was defined as ORi reaching zero, whereas in the control group ventilation was resumed when SpO₂ decreased to 90%. The primary outcome was the time from the onset of apnea to the predefined reventilation threshold. Secondary outcomes included arterial blood gas parameters (pH, PaO₂, PaCO₂) at the time of reventilation, end-tidal carbon dioxide levels, perioperative lung ultrasound findings, post-anesthesia care unit length of stay, and postoperative respiratory outcomes. This study aims to determine whether ORi monitoring provides earlier and clinically meaningful warning of oxygen reserve depletion compared with conventional pulse oximetry, potentially improving patient safety during shared-airway surgery.

Вмешательства

• Процедура oxygen monitoring techniques
  to determine whether ORi monitoring provides earlier and clinically meaningful warning of oxygen reserve depletion compared with conventional pulse oximetry, potentially improving patient safety during shared-airway surgery.

Первичные конечные точки

• Time to Reventilation Threshold [Срок оценки: From the onset of apnea until the predefined reventilation threshold is reached during the intraoperative period (within minutes).]

Вторичные конечные точки (4)

• Arterial Blood Gas Parameters at Reventilation [Срок оценки: From the onset of apnea until the predefined reventilation threshold is reached during the intraoperative period (within minutes).]
• Perioperative Lung Ultrasound Findings [Срок оценки: Preoperatively (before anesthesia induction) and postoperatively in the post-anesthesia care unit (within 1 hour after surgery).]
• Postoperative Oxygenation [Срок оценки: postoperatively in the post-anesthesia care unit (within 1 hour after surgery).]
• End-Tidal Carbon Dioxide (EtCO₂) Level [Срок оценки: During the apneic period, measured at the time of reventilation during surgery.]

Критерии участия

Критерии включения

• Age 18 years or older
• Scheduled for elective endolaryngeal surgery
• Planned general anesthesia with apneic intermittent ventilation
• American Society of Anesthesiologists (ASA) physical status I-III
• Ability to provide written informed consent

Критерии исключения

• Age under 18 years
• Preoperative chronic hypoxemia (baseline SpO₂ < 95%)
• Patients transferred from the intensive care unit
• ASA physical status IV or higher
• Refusal or inability to provide informed consent

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Простое слепое

Основная цель

Лечение

Центры проведения

Turkey (Türkiye) · 1 центр

• Istanbul University, Department of anesthesiology — Istanbul

Публикации

• 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. PMID 32815872
• 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. PMID 26978143

Идентификаторы

NCT: NCT07415161 · 2024/1568

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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