The Effectiveness of FiO2 Titration Guided by the Oxygen Reserve Index in Preventing Hyperoxia.

Determination of the Incidence of Hyperoxia and the Effectiveness of FiO2 Titration Guided by the Oxygen Reserve Index in Preventing Hyperoxia.

Oxygen therapy is the most common treatment modality for patients with hypoxemia, but target values for normoxemia are not clearly defined. Therefore, iatrogenic hyperoxemia is a very common situation. Even though there are many side effects reported related to hyperoxemia and hyperoxemia is shown to be related to worse outcome than expected; clinicians still observe hyperoxemia frequently. Oxygen reserve index (ORi™) (Masimo Corp., Irvine, USA) can guide clinicians in detection of hyperoxia. ORi is a parameter which can evaluate partial pressure of oxygen (PaO2) rating from 0 to 1. There are growing evidences in ORi that it might be helpful to reduce hyperoxia in general anesthesia. Continuous ORi monitoring can be used for detecting and preventing hyperoxia. The ability to perform FiO2 titration with ORi may be an appropriate monitoring management to prevent the harmful effects of hyperoxia.In this study, in patients who underwent major abdominal surgery; It was aimed to investigate the effectiveness of ORi-guided FiO2 titration in preventing hyperoxia.

Fraction of inspired oxygen (FiO2) is titrated guided by oxygen saturation in that range; %95<oxygen saturation≤%98

FiO2 will be titrated by reducing 10% if Ori>0.01 andSpO2 ≥ 98% until Ori is 0.00. FiO2 will not be changed if Ori is 0.00 and %95<oxygen saturation≤%98 FiO2 will be increased by 10% if oxygen saturation <95 or PaO2<60 mmHg

FiO2 will be titrated by reducing 10% if Ori>0.01 and oxygen saturation ≥ 98% until Ori is 0.00. FiO2 will not be changed if Ori is 0.00 and %95<oxygen saturation≤%98 FiO2 will be increased by 10% if oxygen saturation <95 or PaO2<60 mmHg

Fraction of inspired oxygen (FiO2) is titrated guided by oxygen saturation in that range; %95<oxygen saturation≤%98

Correlation of FiO2 value and ORi value. FiO2 adjusted until ORi reaches to zero and %95<oxygen saturation≤%98

Pressure of arterial oxygen is obtain from arterial blood gas analysis as usual practice in 10 min and every hour until surgery is over

Inclusion Criteria: Patients older than 18, Patients scheduled for major abdominal surgery that are expected to last longer than 2 hours Patients that have invasive arterial monitorization American Society of Anesthesiologists physical class I, II or III. Exclusion Criteria: Patients younger than 18 Patients that need to be treated with high doses of vasopressors, Patients having peripheric hypoperfusion, Hemodynamically unstable patients, Patients with hemoglobinopathy, Pregnancy, Morbid obesity (bmi>40 kg/m2), Patients with arrythmia that can result in hemodynamic instability, patients with acute coronary syndrome Acute respiratory failure or ARDS.

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