Effect of single versus multiple dosing on perfluorochemical distribution and elimination during partial liquid ventilation

Miller, Thomas F.; Milestone, Barton; Stern, Robert; Shaffer, Thomas H.; Wolfson, Marla R.

doi:10.1002/(sici)1099-0496(199906)27:6<410::aid-ppul8>3.0.co;2-5

Cited by 21 publications

(7 citation statements)

References 25 publications

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“…Mean evaporation was 13% lower with an intrapulmonary liquid volume of 5 mL?kg -1 , rather than with a volume of 15 mL?kg -1 , representing a value near the functional residual capacity of New Zealand white rabbits. These results are consistent with previous in-vivo studies measuring perfluorocarbon concentrations in the expired air in which the perfluorocarbon concentration was found to decrease over time and with smaller initial doses [1][2][3][4][5][6].…”

Section: Critique Of Methodssupporting

confidence: 92%

“…It has been observed before that perfluorocarbon evaporation is not a constant process, but decreases over time [3]. Elimination also depends on the ventilatory settings, especially respiratory rate and tidal volume.…”

mentioning

confidence: 97%

“…During partial liquid ventilation perfluorocarbons are instilled into the airways from where they are subsequently eliminated by evaporation via the bronchial system. This process is influenced by various factors, like the physicochemical properties of the liquids (especially vapour pressure), the dose instilled into the airways, intrapulmonary perfluorocarbon distribution and respiratory settings [1][2][3][4][5][6]. Only small amounts cross the alveolo-capillary membranes into the vascular space and are stored in intra-and extrathoracic lymph nodes as well as in other organs indicating systemic distribution [7][8][9].…”

mentioning

confidence: 99%

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Partial liquid ventilation: effects of liquid volume and ventilatory settings on perfluorocarbon evaporation

Loer

Kindgen‐Milles²,

Tarnow³

2002

Eur Respir J

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During partial liquid ventilation perfluorocarbons are eliminated mainly by evaporation via the airways. The effects of intrapulmonary perfluorocarbon volume, respiratory rate, tidal volume, as well as the level of end-expiratory pressure on perfluorocarbon elimination from isolated lungs, were studied.Nonperfused rabbit lungs underwent partial liquid ventilation (2-15 mL?kg -1 perfluorocarbon) with variable levels of end-expiratory pressure (0-10 cmH 2 O), respiratory rates (15-60 breaths?min -1 ) and tidal volumes (3.3-10.0 mL?kg -1 ). Evaporative loss of perfluorocarbon was determined gravimetrically as rate of change in lung weight.At constant respiratory settings, intrapulmonary liquid volume determined evaporative loss in a nonlinear fashion. Mean evaporation at a liquid volume of 5 mL?kg -1 was 13% lower compared to evaporation at a liquid volume of 15 mL?kg -1 . Any increase in end-expiratory pressure reduced perfluorocarbon evaporation, e.g. by y50% when end-expiratory pressure was increased from 0 to 10 cmH 2 O. At constant endexpiratory pressure and perfluorocarbon filling evaporation increased in a linear fashion with increasing respiratory rate and tidal volume.In summary, the experiments suggested that evaporative loss of perfluorocarbons during partial liquid ventilation of isolated lungs is increased with increasing intrapulmonary liquid volume, respiratory rate and tidal volume and is reduced in a level-dependent fashion by the application of positive end-expiratory pressure. During partial liquid ventilation perfluorocarbons are instilled into the airways from where they are subsequently eliminated by evaporation via the bronchial system. This process is influenced by various factors, like the physicochemical properties of the liquids (especially vapour pressure), the dose instilled into the airways, intrapulmonary perfluorocarbon distribution and respiratory settings [1][2][3][4][5][6]. Only small amounts cross the alveolo-capillary membranes into the vascular space and are stored in intra-and extrathoracic lymph nodes as well as in other organs indicating systemic distribution [7][8][9].A major variable which appears to influence perfluorocarbon elimination is the amount of liquid within the lungs. It has been observed before that perfluorocarbon evaporation is not a constant process, but decreases over time [3]. Elimination also depends on the ventilatory settings, especially respiratory rate and tidal volume. In addition, the level of end-expiratory pressure may affect elimination since superimposing a positive end-expiratory pressure (PEEP) during partial liquid ventilation may increase functional residual capacity and alveolar ventilation [10][11][12][13][14][15][16]. Such effects are likely to influence intrapulmonary perfluorocarbon distribution as well as the air/liquid interface from which perfluorocarbons evaporate in the expired gas during partial liquid ventilation.It is difficult to control and vary these variables independently from each other during in vivo measurement...

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Section: Critique Of Methodssupporting

confidence: 92%

mentioning

confidence: 97%

mentioning

confidence: 99%

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Partial liquid ventilation: effects of liquid volume and ventilatory settings on perfluorocarbon evaporation

Loer

Kindgen‐Milles²,

Tarnow³

2002

Eur Respir J

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“…It is unclear whether this debris represents alveolar and deep pulmonary secretions that would otherwise not be mobilized or an exudative response to the liquid (74). Dosing and ventilatory management strategies are being refined to optimize the response and improve the cost‐effectiveness of treatment (4,28,75–77).…”

Section: Summary Of Clinical Resultsmentioning

confidence: 99%

“…Based on these properties, the appropriate fluid is matched with the LAV technique chosen. For example, the vapour pressure of the fluids influences the rate of evaporation from the lung and the kinematic viscosity of the fluids influences distribution and pressure requirements for LAV techniques (4,5). Overall, the combination of the physicochemical properties of the PFC liquid and biophysical effects of the liquid on lung mechanics support physiological responses.…”

Section: Introductionmentioning

confidence: 99%

Liquid ventilation: an adjunct for respiratory management

Wolfson¹,

Shaffer²

2004

Pediatric Anesthesia

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Although significant advances in respiratory care have reduced mortality of patients with respiratory failure, morbidity persists, often resulting from iatrogenic mechanisms. Mechanical ventilation with gas has been shown to initiate as well as exacerbate underlying lung injury, resulting in progressive structural damage and release of inflammatory mediators within the lung. Alternative means to support pulmonary gas exchange while preserving lung structure and function are therefore required. Perfluorochemical (PFC) liquids are currently used clinically in a number of ways, such as intravascular PFC emulsions for volume expansion/oxygen carrying/angiography and intracavitary neat PFC liquid for image contrast enhancement or vitreous fluid replacement. As a novel approach to replace gas as the respiratory medium, liquid assisted ventilation (LAV) with PFC liquids has been investigated as an alternative respiratory modality for over 30 years. Currently, there are several theoretical and practical applications of LAV in the immature or mature lung at risk for acute respiratory distress and injury associated with mechanical ventilation.

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