Efficiency of oxygen delivery through different oxygen entrainment devices during sedation under low oxygen flow rate: a bench study

Hsu, Wei Chih; Orr, Joe; Lin, Shih Pin; Yu, Lu; Tsou, Mei-Yung; Westenskow, Dwayne R.; Ting, Chien‐Kun

doi:10.1007/s10877-017-0023-1

Cited by 9 publications

(11 citation statements)

References 18 publications

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“…Previous studies indicated that the FiO 2 is affected by the RR, the inspiratory time, the presence of a reservoir from which entrainment occurs, and the presence of an expiratory pause [ 10 , 27 ]. The increase in FiO 2 with increasing oxygen flow rates through an Ncan has been demonstrated in a mannequin model [ 29 , 32 ] and humans [ 7 , 11 , 24 , 35 ]. The study by Gibson et al, which used a nasal cannula for the administration of low-flow oxygen, resulted in only slight increases in tracheal oxygen concentration (23.6% at 3 LPM and 25.4% at 5 LPM).…”

Section: Discussionmentioning

confidence: 99%

“…This experiment included three levels of resistance (R in L/s/cmH 2 O) and compliance (C in mL/cmH 2 O) of TTL to represent the lung mechanics of normal, obstructive, and restrictive lung diseases, as suggested by the manufacturer and previous studies [ 27 , 28 , 29 , 30 ]. In the normal lung model, R5/C60, R20/C80, and R5/C40 were represented as obstructive and restrictive lung diseases, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Impact of Oxygen Concentration Delivered via Nasal Cannula on Different Lung Conditions: A Bench Study

2021

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Background: Measuring the fraction of inspired oxygen (FiO2) is challenging in spontaneously breathing patients with impaired respiratory mechanics during low-flow nasal cannula. Our study investigates the FiO2 with varied tidal volume (VT) and respiratory rate (RR) among different lung mechanics and provides equations to estimate the FiO2. Methods: Two training and test lungs were used in this study, and the three lung mechanics (normal (R5/C60), restrictive (R20/C80), obstructive (R5/C40)) were designed. Spontaneous breathing with VT (300, 500, and 700 mL) and RR (10, 20, and 30 breaths/min) was simulated. The flow rate of the nasal cannula was set to 1, 3, and 5 L per minute (LPM), and the FiO2 was measured at the carina. Results: The lowest and highest FiO2 were evident during high (700 mL) and low VT (300 mL), respectively, among normal, restrictive, and obstructive lung models. As RR increases, this decreases the FiO2. However, we found that VT and oxygen flow rate are the principal factors influencing measured FiO2 by multiple linear regression analysis. Conclusions: Our data suggest that the actual FiO2 is never as high in spontaneously breathing patients as that estimated. VT and oxygen flow rate had a substantial impact on the FiO2.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Impact of Oxygen Concentration Delivered via Nasal Cannula on Different Lung Conditions: A Bench Study

2021

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“…This is a simulation study and ethical approval was not required as this study did not involve human subjects. To simulate spontaneous breathing, we prepared a model of spontaneous breathing with reference to the model created by Hsu et al (Figure 1 ) [ 12 ]. A ventilator from an anesthesia apparatus (Fabius Plus; Lübeck, Germany: Draeger, Inc.) and test lungs (Dual adult TTL; Grand Rapids, MI: Michigan Instruments, Inc.) were prepared to reproduce spontaneous respiration.…”

Section: Methodsmentioning

confidence: 99%

“…However, measuring FiO 2 in the trachea of the human body is difficult. Some researchers have attempted to simulate FiO 2 with a spontaneous respiration model [ 4 , 12 , 13 ]. Thus, in this study, we aimed to measure FiO 2 using a simulation model of spontaneous respiration.…”

Section: Introductionmentioning

confidence: 99%

Fraction of Inspired Oxygen With Low-Flow Versus High-Flow Devices: A Simulation Study

Kojima¹,

Sendo²,

Okayama³

et al. 2022

Cureus

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Purpose: The fraction of inspired oxygen while administering oxygen to patients must be measured as it represents the alveolar oxygen concentration, which is important from a respiratory physiology viewpoint. Therefore, the purpose of this study was to compare the fractions of inspired oxygen obtained through different oxygen delivery devices. Methods: A simulation model of spontaneous respiration was used. The fractions of inspired oxygen obtained through low- and high-flow nasal cannulas and a simple oxygen mask were measured. The fraction of inspired air was measured every second for 30 s after 120 s of oxygen administration. This was measured three times under each condition. Results: With a low-flow nasal cannula, airflow reduced both the intratracheal fraction of inspired oxygen and extraoral oxygen concentration, indicating that exhalatory respiration occurred during rebreathing and may be involved in increasing the intratracheal fraction of inspired oxygen. Conclusion: Oxygen administration during expiratory flow may lead to an increased oxygen concentration in the anatomical dead space, which may be involved in the increase in the fraction of inspired oxygen. With a high-flow nasal cannula, a high fraction of inspired oxygen can be achieved even at a flow rate of 10 L/min. When determining the optimum amount of oxygen, it is necessary to set an appropriate flow rate for patients and specific conditions without being bound by the fraction of inspired oxygen values alone. It might be difficult to estimate the fraction of inspired oxygen while using a low-flow nasal cannula and simple oxygen mask in clinical situations.

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“…2), as suggested by the manufacturer and previous studies. [27][28][29][30] In the normal lung model was R5/C60, R20/C80 and R5/C40 were represented to obstructive and restrictive lung diseases, respectively. The protocols were performed with a wide-ranging change in the ventilatory pattern of the LTV1200 ventilator [V T :300, 500 and 700mL; f:10, 20 and 30breaths/min]; Oxygen flow rates of 1, 3 and 5L/min were set for the nasal cannula.…”

Section: Lung Model and Testing Protocolmentioning

confidence: 99%

Estimation of oxygen concentration in the airway during inspiration and pre-inspiration with a nasal cannula

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BACKGROUND: In low flow oxygen therapy, FIO2 is difficult to measure in spontaneously breathing patients due to room air dilution and dead space rebreathing, especial in impairments respiratory mechanics. This study determined oxygen concentrations with different tidal volumes and respiratory rates among different lung mechanics and provided equations to estimate oxygen concentrations during standard nasal cannula oxygen therapy. METHODS: Two Training & Test Lung models were used in this study. One simulated spontaneous breathing, whereas the other included an expiratory gas modification bellow. Three lung mechanics [normal (R5/C60), restrictive (R20/C80) and obstructive (R5/C40)] were designed, and spontaneous breathing settings for different tidal volumes(VT) and respiratory rates(f) were simulated by the mechanical ventilator. The nasal cannula used flows of 1, 3 and 5L/min; peak inspired oxygen concentration (FO2 insp.) and pre-inspired oxygen concentration (FO2 pre-insp.) were measured. RESULTS: Increased VT caused a decreased FO2 insp. and FO2 pre-insp., except at 1L/min oxygen flow with a high f (30breaths/min). Multiple regression analysis showed oxygen flow rate, VT and f as the most important factors in predicting oxygen delivery during nasal cannula therapy. Therefore, we provided equations to predict oxygen concentration for managing patients with acute and chronic lung diseases. CONCLUSIONS: Our study suggested that under low-flow nasal cannula therapy, various lung mechanics and respiratory patterns in the normal, restrictive and obstructive lung models will affect the oxygen concentration.

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Efficiency of oxygen delivery through different oxygen entrainment devices during sedation under low oxygen flow rate: a bench study

Cited by 9 publications

References 18 publications

Impact of Oxygen Concentration Delivered via Nasal Cannula on Different Lung Conditions: A Bench Study

Impact of Oxygen Concentration Delivered via Nasal Cannula on Different Lung Conditions: A Bench Study

Fraction of Inspired Oxygen With Low-Flow Versus High-Flow Devices: A Simulation Study

Estimation of oxygen concentration in the airway during inspiration and pre-inspiration with a nasal cannula

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