Objective

To evaluate the oxygen reserve index (ORI) as a noninvasive estimate of the PaO₂ during moderate hyperoxaemia [100–200 mmHg (13.3–26.6 kPa)], and to determine ORI values identifying PaO₂ > 100, > 150 (20.0 kPa) and > 200 mmHg in anaesthetized donkeys with an inspired fraction of oxygen (FiO₂) > 0.95.

Study design

Prospective observational study.

Animals

A group of 28 adult standard donkeys aged (mean ± standard deviation) 4 ± 2 years and weighing 135 ± 15 kg.

Methods

Donkeys were sedated intramuscularly with xylazine and butorphanol; anaesthesia was induced with ketamine and diazepam and maintained with isoflurane in oxygen. An adhesive sensor probe was applied to the donkey’s tongue and connected to a Masimo pulse co-oximeter to determine ORI values. An arterial catheter was inserted into an auricular artery. After ORI signal stabilization, the value was noted and PaO₂ determined by blood gas analysis. The Pearson correlation coefficient was used to assess the relationship between ORI and PaO₂ for oxygen tension < 200 mmHg (< 26.6 kPa). The Youden index was used to identify the value of ORI that detected PaO₂ > 150 and 200 mmHg (20.0 and 26.6 kPa) with the highest sensitivity and specificity.

Results

A total of 106 paired measurements were collected. A mild positive correlation was observed between ORI and PaO₂ for values < 200 mmHg (26.6 kPa; r = 0.52). An ORI > 0.0, > 0.1 and > 0.3 indicated a PaO₂ > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) with negative predictive values > 94%.

Conclusions and clinical relevance

ORI may provide a noninvasive indication of PaO₂ > 100, > 150 and > 200 mmHg (13.3, 20.0 and 26.6 kPa) in anaesthetized donkeys with an FiO₂ > 0.95, although it does not replace blood gas analysis for assessment of oxygenation.

中文翻译：

---

氧储备指数作为麻醉驴动脉氧分压的无创指标：一项初步研究

客观的

评估氧储备指数 (ORI) 作为中度高氧血症 [100–200 mmHg (13.3–26.6 kPa)] 期间PaO ₂的无创估计值，并确定 ORI 值，可识别 PaO ₂ > 100、> 150 (20.0 kPa)和> 200 mmHg 在麻醉驴中吸入的氧气分数 (F i O ₂ ) > 0.95。

学习规划

前瞻性观察研究。

动物

一组28头成年标准驴，年龄（平均值±标准差）4±2岁，体重135±15公斤。

方法

驴用赛拉嗪和布托啡诺肌肉注射镇静；用氯胺酮和地西泮诱导麻醉，并在氧气中用异氟醚维持。将粘性传感器探头应用于驴的舌头并连接到 Masimo 脉搏血氧仪以确定 ORI 值。动脉导管插入耳廓动脉。ORI信号稳定后，记录该值并通过血气分析确定PaO ₂。Pearson 相关系数用于评估氧张力 < 200 mmHg (< 26.6 kPa) 时ORI 和 PaO ₂之间的关系。使用约登指数来确定检测 PaO ₂ > 150 和 200 mmHg（20.0 和 26.6 kPa）的 ORI 值，其灵敏度和特异性最高。

结果

共收集了 106 个配对测量值。对于 < 200 mmHg (26.6 kPa; r  = 0.52) 的值，在 ORI 和 PaO ₂之间观察到轻度正相关。ORI > 0.0、> 0.1 和 > 0.3 表示 PaO ₂ > 100、> 150 和 > 200 mmHg（13.3、20.0 和 26.6 kPa），阴性预测值 > 94%。

结论和临床相关性

ORI 可以为F i O ₂ > 0.95 的麻醉驴提供 PaO ₂ > 100、> 150 和 > 200 mmHg（13.3、20.0 和 26.6 kPa）的无创指征，尽管它不能代替血气分析来评估氧合.