Variation in performance of oxygen therapy devices

Leigh, Julian M.

doi:10.1111/j.1365-2044.1970.tb00192.x

Cited by 75 publications

(43 citation statements)

References 18 publications

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“…The wide scatter on each of these points is similar to that previously found in studies investigating supplemental oxygen supplied to spontaneously ventilating patients via variable performance masks [3] and nasal cannulae [4]. For variable performance masks, the scatter is due to differences in inspiratory flow between patients [3], and the different ventilator settings for each patient in this study is likely to have been the reason for the wide interindividual variation at each flow rate. The results, therefore, show the range of oxygen concentrations that may be seen with different ventilator settings in clinical practice.…”

Section: Discussionsupporting

confidence: 78%

Supplemental oxygen and nasal intermittent positive pressure ventilation

Padkin

Kinnear²

1996

Eur Respir J

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When supplementary oxygen is necessary with nasal intermittent positive pressure ventilation (NIPPV), the optimal route by which it should be added to the ventilator circuit is unknown. We investigated the oxygen concentration received when oxygen was supplied at flow rates between 0 and 6 L·min -1 into the proximal ventilator tubing or the nasal mask whilst patients were ventilated with air.Eleven patients with stable chronic hypercapnic respiratory failure were studied. A calibration curve was produced for each by supplying different known oxygen concentrations through a Monnal D or DCC ventilator and measuring the arterial oxygen saturations achieved. Oxygen was then supplied into the ventilator tubing or nasal mask and arterial saturation again measured. The oxygen concentration received was estimated using the calibration curve. Tracheal oxygen concentration throughout the respiratory cycle was studied in one patient when oxygen was supplied by both routes.Peak inspired oxygen concentration occurred at end-inspiration when oxygen was supplied into the ventilator tubing, but at mid-inspiration when supplied into the nasal mask. However, there was no significant difference between the two routes in the inspired oxygen concentration achieved at all flow rates: 1 L·min -1 supplied approximately 31% oxygen; 2 L·min -1 37%; 3 L·min -1 40%; and 4 L·min -1 44%. Flow rates above 4 L·min -1 had little additional effect.In conclusion, oxygen supplementation during nasal intermittent positive pressure ventilation can be provided into the ventilator tubing or the nasal mask with equal efficiency.

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Section: Discussionsupporting

confidence: 78%

Supplemental oxygen and nasal intermittent positive pressure ventilation

Padkin

Kinnear²

1996

Eur Respir J

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“…The consistent inspired oxygen concentration obtained with the Ventimask has previously been r e p~r t e d .~,~ The more recently marketed lowcapacity masks were intended to operate on the HAFOE principle and therefore to be of the fixed performance type. 8 We have confirmed the efficiency of the venturi entrainment devices to deliver an accurate oxygen concentration to four of the five brands of mask tested. However, only the Ventimask is able to provide a fixed and predictable oxygen concentration under conditions of the changing ventilatory patterns found in clinical practice.…”

Section: Discussionsupporting

confidence: 49%

Fixed performance oxygen masks

Cox

Gillbe

1981

Anaesthesia

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SummaryFour recently introduced low-capacity3xed performance oxygen therapy masks have been compared with the established Ventimask design. Under conditions of varying peak inspiratoryflow rate the low-capacity devices all permit a variable amount of air admixture with a consequent fall in the inspired oxygen conceniration. It is concluded that low-capacity venturi masks are not truejxedperformunce devices under all circumstances. The Ventimasks satisfy their speciJications under all test conditions. A case is made for more rigorous assessment of new so-called pxed performance ' oxygen therapy devices before marketing is permitted.

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“…This is an important issue in clinical practice as hyperoxia is often produced unintentionally in patients who were previously hypoxic. This occurs because high-flow oxygen therapy is often administered by variableperformance face masks (25) and monitoring of its effects is frequently inadequate (46). We found that correcting arterial hypoxia with a hyperoxic gas mixture had more marked effects on heart rate, CI, SVRI, and AI than when air was used.…”

Section: Importance Of Inspired Oxygen Concentration In Determining Tmentioning

confidence: 99%

Effects of short-term isocapnic hyperoxia and hypoxia on cardiovascular function

Thomson

Drummond²,

Waring³

et al. 2006

Journal of Applied Physiology

103

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. Effects of short-term isocapnic hyperoxia and hypoxia on cardiovascular function. J Appl Physiol 101: 809 -816, 2006; doi:10.1152/japplphysiol.01185.2005.-Both hypoxia and hyperoxia have major effects on cardiovascular function. However, both states affect ventilation and many previous studies have not controlled CO 2 tension. We investigated whether hemodynamic effects previously attributed to modified O 2 tension were still apparent under isocapnic conditions. In eight healthy men, we studied blood pressure (BP), heart rate (HR), cardiac index (CI), systemic vascular resistance index (SVRI) and arterial stiffness (augmentation index, AI) during 1 h of hyperoxia (mean end-tidal O 2 79.6 Ϯ 2.0%) or hypoxia (pulse oximeter oxygen saturation 82.6 Ϯ 0.3%). Hyperoxia increased SVRI (18.9 Ϯ 1.9%; P Ͻ 0.001) and reduced HR (Ϫ10.3 Ϯ 1.0%; P Ͻ 0.001), CI (Ϫ10.3 Ϯ 1.7%; P Ͻ 0.001), and stroke index (SI) (Ϫ7.3 Ϯ 1.3%; P Ͻ 0.001) but had no effect on AI, whereas hypoxia reduced SVRI (Ϫ15.2 Ϯ 1.2%; P Ͻ 0.001) and AI (Ϫ10.7 Ϯ 1.1%; P Ͻ 0.001) and increased HR (18.2 Ϯ 1.2%; P Ͻ 0.001), CI (20.2 Ϯ 1.8%; P Ͻ 0.001), and pulse pressure (13.2 Ϯ 2.3%; P ϭ 0.02). The effects of hyperoxia on CI and SVRI, but not the other hemodynamic effects, persisted for up to 1 h after restoration of air breathing. Although increased oxidative stress has been proposed as a cause of the cardiovascular response to altered oxygenation, we found no significant changes in venous antioxidant or 8-iso-prostaglandin F 2␣ levels. We conclude that both hyperoxia and hypoxia, when present during isocapnia, cause similar changes in cardiovascular function to those described with poikilocapnic conditions.

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Variation in performance of oxygen therapy devices

Cited by 75 publications

References 18 publications

Supplemental oxygen and nasal intermittent positive pressure ventilation

Supplemental oxygen and nasal intermittent positive pressure ventilation

Fixed performance oxygen masks

Effects of short-term isocapnic hyperoxia and hypoxia on cardiovascular function

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