Quantitative analysis of the effect of fraction of inspired oxygen on peripheral oxygen saturation in healthy volunteers

Abstract Background The international organization for standardization (ISO) 80601-2-61 dictates that the accuracy of a pulse oximeter should be assessed by a controlled desaturation study. We aimed to characterize the relationship between the fraction of inspired oxygen (FiO 2 ) and peripheral oxygen saturation (SpO 2 ) using a turnover model by retrospectively analyzing the data obtained from previous controlled desaturation studies. We also measured the changes in biomarkers expected to be related to hypoxia (i.e., lactate, carboxyhemoglobin (COHb), and methemoglobin (MetHb)) in response to short-term exposure to hypoxia.Methods Volunteers were exposed to various levels of induced hypoxia over 70−100% arterial oxygen saturation (SaO 2 ). The study period consisted of two rounds of hypoxia and the volunteers were maintained in room air between each round. FiO 2 and SpO 2 were recorded continuously during the study period. A population pharmacodynamic analysis was performed with the NONMEM VII level 4 (ICON Development Solutions, Ellicott City, MD, USA). Lactate, COHb, and MetHb were measured using a CO-oximeter.Results In total, 2899 SpO 2 data points obtained from 20 volunteers were used to determine the pharmacodynamic characteristics. The pharmacodynamic parameters were as follows: k out = 0.942 1/min, Imax = 0.802, IC 50 = 85.3%, γ = 27.3. The changes in SpO 2 due to decreases in FiO 2 well explained by the turnover model with inhibitory function as a sigmoidal model. As SpO 2 decreased, lactate and COHb increased as a whole, and COHb showed the best correlation (Pearson’s correlation, R 2 =0.3263, P < 0.0001).Conclusion The potency of FiO 2 required to reduce SpO 2 from 100% to 70% was 14.7%. Carboxyhemoglobin has the potential to be a useful biomarker for acute hypoxia.

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Evaluation of Knowledge of Oxygen Therapy and Reading of Flowmeter among the Health Workers in the Pediatric Unit of the Hospital Universitario San Ignacio, Bogotá, Colombia

Universitas Médica ◽

10.11144/javeriana.umed59-3.oxig ◽

2018 ◽

Vol 59 (3) ◽

pp. 1-8

Author(s):

Elly Morros González ◽

Diana Estrada Cano ◽

Marcela Murillo Galvis ◽

Jos Carlos Montes Correa ◽

Nelcy Rodríguez Malagón ◽

...

Keyword(s):

Adverse Effects ◽

Oxygen Saturation ◽

Oxygen Therapy ◽

Health Workers ◽

Supplemental Oxygen ◽

Cross Sectional Study ◽

Peripheral Oxygen Saturation ◽

Cross Sectional ◽

Fraction Of Inspired Oxygen ◽

Supplemental Oxygen Therapy

Introduction: Supplemental oxygen is considered a pharmaceutical drug; therefore, it can produce adverse effects. Lack of consensus regarding the reading of oxygen flowmeters and the peripheral oxygen saturation (SpO2) goals can influence clinical and paraclinical decisions and hospital stay length. Objective: To assess knowledge on oxygen therapy, adverse effects, SpO2 goals and reading of oxygen flowmeters among personnel in the Pediatric Unit at Hospital Universitario San Ignacio, Bogotá, Colombia. Methodology: Cross-sectional study derived from convenience sampling through a self-applied survey between December 2016 and January 2017. The poll evaluated topics on supplemental oxygen therapy fundamentals and adverse effects, SpO2 goals and flowmeter readings through flowmeters photographs indicating a specific fraction of inspired oxygen (FiO2). Results: The response rate was 77% from 259 subjects. 22% considered that the oxygen saturation either increases or remains the same during sleep periods in children. 78% of participants knew at least one complication associated to prolonged oxygen therapy and 67% due to supplemental oxygen concentration greater than required. In neonatal population, 10% considered oxygen saturation goals equal to or greater than 96%. In the flowmeter’s reading evaluation, incorrect answers ranged from 9 to 19%. Conclusion: It is imperative to reinforce updated concepts on oxygen therapy, with emphasis in SpO2 goals, adverse effects and appropriate flowmeter’s readings through periodic educational campaigns.

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Correlation Between the Ratio of Oxygen Saturation to Fraction of Inspired Oxygen and the Ratio of Partial Pressure of Oxygen to Fraction of Inspired Oxygen in Detection and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome

Cureus ◽

10.7759/cureus.18353 ◽

2021 ◽

Author(s):

Pooja D Lohano ◽

Sadam H Baloch ◽

Murtaza A Gowa ◽

Syed J Raza ◽

Lareb Soomro ◽

...

Keyword(s):

Acute Respiratory Distress Syndrome ◽

Risk Stratification ◽

Respiratory Distress Syndrome ◽

Respiratory Distress ◽

Oxygen Saturation ◽

Partial Pressure ◽

Distress Syndrome ◽

Partial Pressure Of Oxygen ◽

Fraction Of Inspired Oxygen ◽

Inspired Oxygen

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Nitric Oxide Story

Anesthesiology ◽

10.1097/aln.0000000000002579 ◽

2019 ◽

Vol 130 (3) ◽

pp. 435-440 ◽

Cited By ~ 1

Author(s):

Warren M. Zapol

Keyword(s):

Nitric Oxide ◽

Pulmonary Hypertension ◽

Oxygen Saturation ◽

Persistent Pulmonary Hypertension ◽

Pulmonary Vasculature ◽

Oxygen Tensions ◽

Low Levels ◽

Fraction Of Inspired Oxygen ◽

Inspired Oxygen ◽

Inhaled No

Abstract Inhaled Nitric Oxide in Persistent Pulmonary Hypertension of the Newborn. By Roberts JD, Polaner DM, Lang P, and Zapol WM. Lancet 1992; 130:435–40. Reprinted with permission. NO has vasodilatory effects on the pulmonary vasculature in adults and animals. We examined the effects on systemic oxygenation and blood pressure of inhaling up to 80 parts per million by volume of NO at fraction of inspired oxygen 0.9 for up to 30 min by six infants with persistent pulmonary hypertension of the newborn. In all infants, this treatment rapidly and significantly increased preductal oxygen saturation; in five infants, postductal oxygen saturation and oxygen tensions also increased. Inhalation of NO did not cause systemic hypotension or raise methemoglobin. These data suggest that low levels of inhaled NO have an important role in the reversal of hypoxemia due to persistent pulmonary hypertension of the newborn.

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Ventilatory parameters measured during a physiological study of simulated powered air-purifying respirator failure in healthy volunteers

Anaesthesia and Intensive Care ◽

10.1177/0310057x20978982 ◽

2021 ◽

pp. 0310057X2097898

Author(s):

Lachlan F Miles ◽

Timothy Makar ◽

Chad W Oughton ◽

Philip J Peyton

Keyword(s):

Carbon Dioxide ◽

Partial Pressure ◽

Healthy Volunteers ◽

Minute Ventilation ◽

Peripheral Oxygen Saturation ◽

Thermal Discomfort ◽

Fraction Of Inspired Oxygen ◽

Mechanical Devices ◽

End Tidal ◽

High Level

Powered air-purifying respirators (PAPR) are a high level of respiratory personal protective equipment. Like all mechanical devices, they are vulnerable to failure. The precise physiological consequences of failure in live subjects have not previously been reported. We conducted an observational safety study simulating PAPR failure in a group of nine healthy volunteers, wearing loose-fitting hoods, who were observed for a period of ten minutes, or until they requested the experiment be aborted, with continuous monitoring of gas exchange. Relative to baseline, participants demonstrated median reductions in peripheral oxygen saturation of 3.5% (95% confidence interval (CI) –4% to –2%; P = 0.0039) and fraction of inspired oxygen of 0.045 (95% CI –0.05 to –0.04; P = 0.0039), and median increases in inspired partial pressure of carbon dioxide of 27 mmHg (95% CI 23.5–32 mmHg; P = 0.0039), end-tidal partial pressure of carbon dioxide of 11 mmHg (95% CI 7–16 mmHg; P = 0.0039) and minute ventilation of 30 l/min (95% CI 19.4–35.9 l/min; P = 0.0039). Median collateral entrainment of room air into the hood was 17.6 l/min (interquartile range 12.3–27.0 l/min). All subjects reported thermal discomfort, with two (22.2%) requesting early termination of the experiment. Whilst the degree of rebreathing in this experiment was not sufficient to cause dangerous physiological derangement, the degree of reported thermal discomfort combined with the consequences of entrainment of possibly contaminated air into the hood, pose a risk to wearers in the event of failure.

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Efficacy and safety of endotracheal instillation of iloprost for persistent pulmonary hypertension of the newborn

Cardiology in the Young ◽

10.1017/s1047951121005072 ◽

2022 ◽

pp. 1-7

Author(s):

Asli Okbay Gunes ◽

Murat Ciftel ◽

Mehmet Emcet Timur ◽

Ceren Dedebali ◽

Betul Zehra Pirdal

Keyword(s):

Pulmonary Hypertension ◽

Oxygen Saturation ◽

Saturation Index ◽

Persistent Pulmonary Hypertension ◽

Systolic Pulmonary Artery Pressure ◽

Mean Airway Pressure ◽

Pressure Oxygen ◽

Before And After ◽

Fraction Of Inspired Oxygen ◽

Inspired Oxygen

Abstract Objective: To determine the efficacy and safety of endotracheal instillation of iloprost as a rescue therapy for persistent pulmonary hypertension of the newborn. Methods: Neonates diagnosed with persistent pulmonary hypertension who were unresponsive to standard treatment protocol applied for persistent pulmonary hypertension in our unit, and who were being followed up with mechanical ventilation, were included in the study. Iloprost was instilled endotracheally as a rescue treatment. Systolic pulmonary artery pressure, oxygen saturation index, mean airway pressure, fraction of inspired oxygen, preductal and postductal venous oxygen saturation, heart rate, and blood pressure were recorded before and after 30 minutes of endotracheal iloprost instillation. Adverse events after endotracheal iloprost were recorded. Results: Twenty neonates were included. The median gestational age and birth weight were found to be 37 (30.5-38) weeks and 2975 (2125-3437.5) grams, respectively. When compared to the period before endotracheal iloprost instillation, systolic pulmonary artery pressure, oxygen saturation index, mean airway pressure, and fraction of inspired oxygen values significantly decreased (p < 0.001, p < 0.001, p = 0.021, p = 0.001, respectively), whereas preductal and postductal oxygen saturation values significantly increased 30 minutes after the endotracheal iloprost instillation (p = 0.002, p < 0.001, respectively). There were no significant differences in heart rate and blood pressure values before and after the iloprost administration. No adverse events were observed. Conclusion: Endotracheal instillation of iloprost was found to be an effective and safe therapy for persistent pulmonary hypertension unresponsive to conventional treatment.

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