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Alapati D, Shaffer TH. Administration of Drugs/Gene Products to the Respiratory System: A Historical Perspective of the Use of Inert Liquids. Front Physiol 2022; 13:871893. [PMID: 35620598 PMCID: PMC9127416 DOI: 10.3389/fphys.2022.871893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 03/31/2022] [Indexed: 11/20/2022] Open
Abstract
The present review is a historical perspective of methodology and applications using inert liquids for respiratory support and as a vehicle to deliver biological agents to the respiratory system. As such, the background of using oxygenated inert liquids (considered a drug when used in the lungs) opposed to an oxygen-nitrogen gas mixture for respiratory support is presented. The properties of these inert liquids and the mechanisms of gas exchange and lung function alterations using this technology are described. In addition, published preclinical and clinical trial results are discussed with respect to treatment modalities for respiratory diseases. Finally, this forward-looking review provides a comprehensive overview of potential methods for administration of drugs/gene products to the respiratory system and potential biomedical applications.
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Affiliation(s)
- Deepthi Alapati
- Nemours Children’s Health, Wilmington, DE, United States
- Sidney Kimmel School of Medicine, Thomas Jefferson University, Philadelphia, PA, United States
- *Correspondence: Deepthi Alapati, ; Thomas H. Shaffer,
| | - Thomas H. Shaffer
- Nemours Children’s Health, Wilmington, DE, United States
- Sidney Kimmel School of Medicine, Thomas Jefferson University, Philadelphia, PA, United States
- Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
- *Correspondence: Deepthi Alapati, ; Thomas H. Shaffer,
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Rieger-Fackeldey E, Jonzon A, Schulze A, Sedin G, Sindelar R. Pulmonary stretch receptor activity during partial liquid ventilation with different pressure waveforms. Respir Physiol Neurobiol 2020; 276:103413. [PMID: 32044447 DOI: 10.1016/j.resp.2020.103413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 11/27/2022]
Abstract
BACKGROUND The aim of the present study was to investigate pulmonary stretch receptor activity (PSR) under different peak inspiratory pressures (PIPs) and inspiratory pressure waveforms during partial liquid (PLV) and gas ventilation (GV). METHODS PSR instantaneous impulse frequency (PSRfimp) was recorded from single fibers in the vagal nerve during PLV and GV in young cats. PIPs were set at 1.2/1.8/2.2/2.7 kPa, and square and sinusoidal pressure waveforms were applied. RESULTS PSRfimp at the start of inspiration increased with increasing PIPs, and was steeper and higher with square than with sinusoidal waveforms (p < 0.05). Total number of impulses, peak and mean PSRfimp were lower during PLV than GV at the lowest and highest PIPs (p < 0.025). Time to peak PSRfimp was shorter with square than with sinusoidal waveforms at all pressures and ventilations (p < 0.005). Irrespective of waveform, lower PIPs yielded lower ventilation during PLV. CONCLUSION As assessed by PSRfimp, increased PIPs do not expose the lungs to more stretching during PLV than during GV, with only minor differences between square and sinusoidal waveforms.
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Affiliation(s)
- Esther Rieger-Fackeldey
- Department of Women´s and Children´s Health, Section for Pediatrics, Uppsala University, Uppsala, Sweden; Perinatal Center, Neonatology, Klinikum Grosshadern, Ludwig Maximilian University, Munich, Germany; Department of Pediatrics, Klinikum Rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
| | - Anders Jonzon
- Department of Women´s and Children´s Health, Section for Pediatrics, Uppsala University, Uppsala, Sweden.
| | - Andreas Schulze
- Perinatal Center, Neonatology, Klinikum Grosshadern, Ludwig Maximilian University, Munich, Germany.
| | - Gunnar Sedin
- Department of Women´s and Children´s Health, Section for Pediatrics, Uppsala University, Uppsala, Sweden
| | - Richard Sindelar
- Department of Women´s and Children´s Health, Section for Pediatrics, Uppsala University, Uppsala, Sweden.
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3
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Degraeuwe P, Vos GD, Blanco CE. Perfluorochemical Liquid Ventilation: From the Animal Laboratory to the Intensive Care Unit. Int J Artif Organs 2018. [DOI: 10.1177/039139889501801020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Perfluorochemical or perfluorocarbon liquids have an enormous gas-carrying capacity. During tidal liquid ventilation the respiratory medium of both functional residual capacity and tidal volume is replaced by neat perfluorocarbon liquid. Tidal liquid ventilation is characterized by convective and diffusive limitations, but offers the advantage of preserved functional residual capacity, high compliance and improved ventilation-perfusion matching. During partial liquid ventilation only the functional residual capacity is replaced by perfluorocarbon liquid. Both tidal and partial liquid ventilation improve gas exchange and lung mechanics in hyaline membrane disease, adult respiratory distress models and meconium aspiration. Compared to gas ventilation, there is less histologic evidence of barotrauma after liquid ventilation. Cardio-pulmonary interaction, inherent to the high density of liquid, and long term safety need further study. However, extrapolating from animal data, and taking into account promising human pilot studies, liquid ventilation has the desired properties to occupy an important place in the therapy of restrictive lung disease in man.
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Affiliation(s)
- P.L.J. Degraeuwe
- Department of Paediatrics, University Hospital Maastricht - The Netherlands
| | - G. D. Vos
- Department of Paediatrics, University Hospital Maastricht - The Netherlands
| | - C. E. Blanco
- Department of Paediatrics, University Hospital Maastricht - The Netherlands
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Abstract
Over the last years, physiological studies have proved that ventilation with a oxygenated liquid perfluorocarbon (PFC) provides effective gas exchange and acid base balance and improves lung function and recovery Low surface tension and high respiratory gas solubility enable adequate oxygenation and carbon dioxide removal at low insufflation pressure. The elimination of air-liquid interfacial surface tension has recently suggested the adoption of total liquid PFC ventilation as an investigational therapy for severe respiratory distress in human infants. This work is aimed to determine the optimal volumes of PFC to be delivered, the frequency of the ventilatory cycle, the oxygen flow rate and the best circuit set up for neonatal application. The optimisation was obtained through the implementation of a simulation mathematical model of oxygen diffusion in a PFC-ventilated lung and of gas exchange between alveolar environment and pulmonary blood flow. The results show that total liquid ventilation is a valid alternative to traditional gas ventilation, particularly when immature neonates with insufficient or absent production of surfactant are concerned.
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Affiliation(s)
- Mi. Costantino
- Dipartimento di Bioingegneria, Politecnico di Milano, Milano - Italy
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Rey-Santano C, Mielgo V, Gastiasoro E, Valls-i-Soler A, Murgia X. Effect of surfactant and partial liquid ventilation treatment on gas exchange and lung mechanics in immature lambs: influence of gestational age. PLoS One 2013; 8:e56127. [PMID: 23418521 PMCID: PMC3571983 DOI: 10.1371/journal.pone.0056127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 01/04/2013] [Indexed: 12/05/2022] Open
Abstract
Objectives Surfactant (SF) and partial liquid ventilation (PLV) improve gas exchange and lung mechanics in neonatal RDS. However, variations in the effects of SF and PLV with degree of lung immaturity have not been thoroughly explored. Setting Experimental Neonatal Respiratory Physiology Research Unit, Cruces University Hospital. Design Prospective, randomized study using sealed envelopes. Subjects 36 preterm lambs were exposed (at 125 or 133-days of gestational age) by laparotomy and intubated. Catheters were placed in the jugular vein and carotid artery. Interventions All the lambs were assigned to one of three subgroups given: 20 mL/Kg perfluorocarbon and managed with partial liquid ventilation (PLV), surfactant (Curosurf®, 200 mg/kg) or (3) no pulmonary treatment (Controls) for 3 h. Measurements and Main Results Cardiovascular parameters, blood gases and pulmonary mechanics were measured. In 125-day gestation lambs, SF treatment partially improved gas exchange and lung mechanics, while PLV produced significant rapid improvements in these parameters. In 133-day lambs, treatments with SF or PLV achieved similarly good responses. Neither surfactant nor PLV significantly affected the cardiovascular parameters. Conclusion SF therapy response was more effective in the older gestational age group whereas the effectiveness of PLV therapy was not gestational age dependent.
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Affiliation(s)
- Carmen Rey-Santano
- Research Unit for Experimental Neonatal Respiratory Physiology, Cruces University Hospital, Barakaldo, Bizkaia, Spain.
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Acute Lung Injury: Acute Respiratory Distress Syndrome. MECHANICAL VENTILATION 2008. [PMCID: PMC7149661 DOI: 10.1016/b978-0-7216-0186-1.50008-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Abstract
In this review of liquid ventilation, concepts and applications are presented that summarise the pulmonary applications of perfluorochemical liquids. Beginning with the question of whether this alternative form of respiratory support is needed and ending with lessons learned from clinical trials, the various methods of liquid assisted ventilation are compared and contrasted, evidence for mechanoprotective and cytoprotective attributes of intrapulmonary perfluorochemical liquid are presented and alternative intrapulmonary applications, including their use as vehicles for drugs, for thermal control and as imaging agents are presented.
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Affiliation(s)
- Marla R Wolfson
- Department of Physiology, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, PA 19140, USA
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Foley DS, Brah R, Bull JL, Brant DO, Grotberg JB, Hirschl RB. Total liquid ventilation: dynamic airway pressure and the development of expiratory flow limitation. ASAIO J 2005; 50:485-90. [PMID: 15497390 DOI: 10.1097/01.mat.0000139305.89565.4a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Expiratory flow limitation occurs during total liquid ventilation (TLV), and is characterized by the sudden development of excessively negative intratracheal pressures without increases in flow. The purpose of this study was to identify a dynamic signal for the servoregulation of expiratory flow (Ve), by determining the range of dynamic intratracheal pressures [P(T)], which mark the onset of flow limitation during liquid expiration, where choke occurs at the critical pressure (Pc). The lungs of rabbits were filled with perflurocarbon to an end-inspiratory lung volume (EILV) of 20, 30, or 40cc/kg and connected to a piston driven liquid ventilator, which removed perfluorocarbon at a rate (Vs) of 2.5, 5.0, or 7.5 ml/s. Nine animals per EILV group were used (27 animals total), and within each EILV group each (Vs) was used three times. P(T) and (Ve) (T) were measured at the tracheostomy tube, and dP/dT was calculated from P(T). Pc was determined within each EILV/(Vs) group by examining the average dP/dT curve for the first significant change from baseline. Pc ranged from -6.02 +/- 1.83 to -9.02 +/- 3.2 mm Hg. In general, the higher the EILV, the more negative the Pc. We conclude that Pc during TLV varies within a limited range in rabbits. These data may be used to maximize expired volume during TLV by sequentially tapering flow rates as this critical range of pressures is approached.
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Affiliation(s)
- David S Foley
- University of Michigan Hospitals, Ann Arbor, MI 48109-0245, USA
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Tredici S, Komori E, Funakubo A, Brant DO, Bull JL, Bartlett RH, Hirschl RB. A prototype of a liquid ventilator using a novel hollow-fiber oxygenator in a rabbit model. Crit Care Med 2004; 32:2104-9. [PMID: 15483421 DOI: 10.1097/01.ccm.0000142701.41679.1b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE A functional total liquid ventilator should be simple in design to minimize operating errors and have a low priming volume to minimize the amount of perfluorocarbon needed. Closed system circuits using a membrane oxygenator have partially met these requirements but have high resistance to perfluorocarbon flow and high priming volume. To further this goal, a single piston prototype ventilator with a low priming volume and a new high-efficiency hollow-fiber oxygenator in a circuit with a check valve flow control system was developed. DESIGN Prospective, controlled animal laboratory study. SETTING Research facility at a university medical center. SUBJECTS Seven anesthetized, paralyzed, normal New Zealand rabbits INTERVENTIONS The prototype oxygenator, consisting of cross-wound silicone hollow fibers with a surface area of 1.5 m2 with a priming volume of 190 mL, was tested in a bench-top model followed by an in vivo rabbit model. Total liquid ventilation was performed for 3 hrs with 20 mL.kg(-1) initial fill volume, 17.5-20 mL.kg(-1) tidal volume, respiratory rate of 5 breaths/min, inspiratory/expiratory ratio 1:2, and countercurrent sweep gas of 100% oxygen. MEASUREMENTS AND MAIN RESULTS Bench top experiments demonstrated 66-81% elimination of CO2 and 0.64-0.76 mL.min(-1) loss of perfluorocarbon across the fibers. No significant changes in PaCO2 and PaO2 were observed. Dynamic airway pressures were in a safe range in which ventilator lung injury or airway closure was unlikely (3.6 +/- 0.5 and -7.8 +/- 0.3 cm H2O, respectively, for mean peak inspiratory pressure and mean end expiratory pressure). No leakage of perfluorocarbon was noted in the new silicone fiber gas exchange device. Estimated in vivo perfluorocarbon loss from the device was 1.2 mL.min(-1). CONCLUSIONS These data demonstrate the ability of this novel single-piston, nonporous hollow silicone fiber oxygenator to adequately support gas exchange, allowing successful performance of total liquid ventilation.
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Affiliation(s)
- Stefano Tredici
- Department of Surgery, University of Michigan, Ann Arbor, MI, USA
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Rieger-Fackeldey E, Sindelar R, Jonzon A, Schulze A, Sedin G. Pulmonary Stretch Receptor Activity during Partial Liquid Ventilation in Cats with Healthy Lungs. Neonatology 2004; 86:73-80. [PMID: 15084808 DOI: 10.1159/000077781] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Accepted: 01/24/2004] [Indexed: 11/19/2022]
Abstract
AIM To study whether pulmonary stretch receptor (PSR) activity in mechanically ventilated young cats with healthy lungs during partial liquid ventilation (PLV) is different from that during gas ventilation (GV). METHODS In 10 young cats (4.4 +/- 0.4 months, 2.3 +/- 0.3 kg; mean +/- SD), PSR instantaneous impulse frequency (PSR fimp) was recorded from single fibres in the vagal nerve during GV and PLV with perfluorocarbon (30 ml/kg) at increasing positive inspiratory pressures (PIP; 1.2, 1.8, 2.2 and 2.7 kPa), and at a positive end-expiratory pressure of 0.5 kPa. RESULTS All PSRs studied during GV maintained their phasic character with increased impulse frequency during inspiration during PLV. Peak PSRfimp was lower at PIP 1.2 kPa (p < 0.05) and at PIP 2.7 kPa (p = 0.10) during PLV than during GV, giving a lower number of PSR impulses at these two settings during PLV (p < 0.05). CONCLUSION The phasic character of PSR activity is similar during GV and PLV. PSR activity is not higher during PLV than during GV in cats with healthy lungs, indicating no extensive stretching of the lung during PLV.
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Affiliation(s)
- Esther Rieger-Fackeldey
- Department of Women's and Children's Health and Department of Physiology, Uppsala University, Uppsala, Sweden.
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Meinhardt JP, Sawada S, Quintel M, Hirschl RB. Comparison of Static Airway Pressures During Total Liquid Ventilation While Applying Different Expiratory Modes and Time Patterns. ASAIO J 2004; 50:68-75. [PMID: 14763494 DOI: 10.1097/01.mat.0000104821.51259.f9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
To compare pump driven (active) and gravity-siphon (passive) expiration modes during perfluorocarbon total liquid ventilation (TLV), a liquid ventilator was developed capable of providing either expiration mode. In a prospective, controlled laboratory study, 90 rabbits (3.2 +/- 0.1 kg) were anesthetized, tracheotomized, killed. After prefill with 12 ml/kg perflubron and TLV for 90 minutes (tidal volume 12 ml/kg, I:E ratio 1:2), randomly using passive (height 40 or 80 cm) or active expiration, respiratory rates were 4, 8, or 12/min. Static peak inspiratory and end-expiratory intratracheal pressures were measured at 5 minute intervals. Peak inspiratory and end-expiratory were constant in active groups, and increases in all 40 cm and 80 cm passive groups were significant. Differences between groups were significant for expiratory mode but not for respiratory rates. Only passive groups showed significant increases in body weight after TLV. Percentage of fluorothoraces was 10% using active and 85% using passive expiration. Based upon the stability of intrapulmonary pressures and volumes and a reduced rate of fluorothoraces, active expiration is more efficient than passive drainage during TLV.
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Affiliation(s)
- Jürgen P Meinhardt
- Department of Anesthesiology and Intensive Care, Universitätsklinikum Mannheim, Germany.
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12
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Gregor T, Schmalisch G, Burkhardt W, Proquitté H, Wauer RR, Rüdiger M. Aerosolization of perfluorocarbons during mechanical ventilation: an in vitro study. Intensive Care Med 2003; 29:1354-60. [PMID: 12698244 DOI: 10.1007/s00134-003-1733-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2002] [Accepted: 02/21/2003] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Inhalation of perfluorocarbons (PFC) has been suggested as a new and promising technique of PFC delivery in animal models of severe lung injury. However, no in vitro data were available on the efficacy of PFC aerosolization during mechanical ventilation. Therefore, the aim of the in vitro study was to investigate the influence of physical properties of PFC and the ventilatory settings on the amount of PFC delivered into the lung. DESIGN In vitro lung model study. SETTING University research laboratory. MEASUREMENTS AND RESULTS Two different PFC (PF 5080 and PFOB) were aerosolized with a PariBoy jet nebulizer. Using a PFC selective adsorber, the effect of endotracheal tube size (2 mm and 3 mm diameter) on delivery of PFC was investigated. PFC delivery was estimated by continuous measurement of weight gain of the adsorber (adsorption rate). Finally, the influence of respiratory rate and tidal volume on adsorption rate (AR) was studied. AR was significantly reduced by a decreasing tube diameter and ranged from 1.45+/-0.03 ml/min (no tube) to 0.93+/-0.03 ml/min (2.0 mm) for PF 5080 (vapor pressure 51 mmHg) and from 0.49+/-0.06 ml/min to 0.32+/-0.04 ml/min for PFOB (11 mmHg). PFC-aerosolization into a ventilatory circuit with simulation of spontaneous tidal breathing (minute volume 600 ml) reduced AR to 0.16+/-0.02 ml/min. During mechanical ventilation, changes in respiratory rate and tidal volume, which reduce minute ventilation, caused a decrease in AR. CONCLUSION The amount of PFC that can be delivered into the lung by aerosolization is very small and is influenced by PFC properties, tube size, and ventilatory settings.
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Affiliation(s)
- Tobias Gregor
- Clinic for neonatology, Charité Campus Mitte, Schumannstrasse 21, 10098, Berlin, Germany
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Abstract
OBJECTIVES The recognition that alveolar overdistension rather than peak inspiratory airway pressure is the primary determinant of lung injury has shifted our understanding of the pathogenesis of ventilator-induced side effects. In this review, contemporary ventilatory methods, supportive treatments, and future developments relevant to pediatric critical care are reviewed. DATA SYNTHESIS A strategy combining recruitment maneuvers, low-tidal volume, and higher positive end-expiratory pressure (PEEP) decreases barotrauma and volutrauma. Given that appropriate tidal volumes are critical in determining adequate alveolar ventilation and avoiding lung injury, volume-control ventilation with high PEEP levels has been proposed as the preferable protective ventilatory mode. Pressure-related volume control ventilation and high-frequency oscillatory ventilation (HFOV) have taken on an important role as protective lung strategies. Further data are required in the treatment of children, confirming the preliminary results in specific lung pathologies. Spontaneous breathing supported artificially during inspiration (pressure support ventilation) is widely used to maintain or reactivate spontaneous breathing and to avoid hemodynamic variation. Volume support ventilation reduces the need for manual adaptation to maintain stable tidal and minute volume and can be useful in weaning. Prone positioning and permissive hypercapnia have taken on an important role in the treatment of patients undergoing artificial ventilation. Surfactant and nitric oxide have been proposed in specific lung pathologies to facilitate ventilation and gas exchange and to reduce inspired oxygen concentration. Investigation of lung ventilation using a liquid instead of gas has opened new vistas on several lung pathologies with high mortality rates. RESULTS The conviction emerges that the best ventilatory treatment may be obtained by applying a combination of types of ventilation and supportive treatments as outlined above. Early treatment is important for the overall positive final result. Lung recruitment maneuvers followed by maintaining an open lung favor rapid resolution of pathology and reduce side effects. CONCLUSIONS The methods proposed require confirmation through large controlled clinical trials that can assess the efficacy reported in pilot studies and case reports and define the optimal method(s) to treat individual pathologies in the various pediatric age groups.
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Affiliation(s)
- Giuseppe A Marraro
- Pediatric Intensive Care Unit, Fatebenefratelli and Ophthalmiatric Hospital, Milan, Italy.
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Rödl S, Urlesberger B, Knez I, Dacar D, Zobel G. Partial liquid ventilation versus conventional mechanical ventilation with high PEEP and moderate tidal volume in acute respiratory failure in piglets. Pediatr Res 2002; 52:225-32. [PMID: 12149500 DOI: 10.1203/00006450-200208000-00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This prospective randomized pilot study aimed to test the hypotheses that partial liquid ventilation combined with a high positive end-expiratory pressure (PEEP) and a moderate tidal volume results in improved gas exchange and lung mechanics without negative hemodynamic influences compared with conventional mechanical ventilation in acute lung injury in piglets. Acute lung injury was induced in 12 piglets weighing 9.0 +/- 2.4 kg by repeated i.v. injections of oleic acid and repeated lung lavages. Thereafter, the animals were randomly assigned either to partial liquid ventilation (n = 6) or conventional mechanical ventilation (n = 6) at a fractional concentration of inspired O(2) of 1.0, a PEEP of 1.2 kPa, a tidal volume < 10 mL/kg body weight (bw), a respiratory rate of 24 breaths/min, and an inspiratory/expiratory ratio of 1:2. Perfluorocarbon liquid 30 mL/kg bw was instilled into the endotracheal tube over 10 min followed by 5 mL/kg bw/h. Continuous monitoring included ECG, mean right atrial, pulmonary artery, pulmonary capillary, and arterial pressures, arterial blood gas, and partial pressure of end-tidal CO(2) measurements. When compared with control animals, partial liquid ventilation resulted in significantly better oxygenation with improved cardiac output and oxygen delivery. Dead space ventilation appeared to be lower during partial liquid ventilation compared with conventional mechanical ventilation. No significant differences were observed in airway pressures, pulmonary compliance, and airway resistance between both groups. The results of this pilot study suggest that partial liquid ventilation combined with high PEEP and moderate tidal volume improves oxygenation, dead space ventilation, cardiac output, and oxygen delivery compared with conventional mechanical ventilation in acute lung injury in piglets but has no significant influence on lung mechanics.
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Cox CA, Fox WW, Weiss CM, Wolfson MR, Shaffer TH. Liquid ventilation: Gas exchange, perfluorochemical uptake, and biodistribution in an acute lung injury. Pediatr Crit Care Med 2002; 3:288-296. [PMID: 12780971 DOI: 10.1097/00130478-200207000-00017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE: Compare the physiologic, histologic, and biochemical findings of tidal and partial liquid ventilation (PLV) with gas ventilated lambs with an acute lung injury. DESIGN: Experimental, prospective randomized controlled study. SETTING: School of medicine, department of physiology. SUBJECTS: Eighteen newborn lambs (</=1 wk old). INTERVENTIONS: Injury was established by using HCl saline lavages. Seven lambs underwent tidal liquid ventilation (TLV), five underwent PLV, and six underwent gas ventilation (GV) for 4 hrs. Measurements: Sequential arterial blood chemistries were performed. Ventilation efficiency index, arterial-alveolar Po(2), and physiologic shunt were calculated. Blood and tissue were analyzed for perfluorochemical fluid. Histologic examinations of lungs were performed. MAIN RESULTS: TLV oxygenation was significantly better (p <.001) than PLV and GV. Paco(2) was similar in all three groups. Ventilation efficiency index was significantly better (p <.01) in the TLV group as compared with the PLV and GV groups. Physiologic shunt was significantly less in the TLV injury group (p <.01) than the PLV and GV groups. Perfluorochemical fluid blood level of 2.3 +/- 0.32 &mgr;g/mL in the PLV group was significantly lower (p <.01) than TLV of 7.8 +/- 0.71 &mgr;g/mL; there was a difference (p <.01) as function of time in the TLV and no difference in the PLV injury group. There were no differences in tissue perfluorochemical fluid levels as a function of ventilation ([mean +/- sem] TLV, 219 +/- 26 &mgr;g/g; PLV injury, 184 +/- 26 &mgr;g/g). There was a significant difference in perfluorochemical fluid levels as a function of tissue (p <.001). CONCLUSION: In severe lung injury, this study demonstrates that physiologic gas exchange can be maintained with TLV or PLV. Physiologic shunt was less in the TLV group as compared with PLV or GV. Additionally, perfluorochemical fluid in the blood and tissue is low during PLV and TLV relative to that associated with intravenous administration of perfluorochemical fluid emulsion.
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Affiliation(s)
- Cynthia A. Cox
- Neonatology Service, Bryn Mawr Hospital, Bryn Mawr, PA; Thomas Jefferson University, Philadelphia, PA; the Department of Neonatology, Children's Hospital of Philadelphia, Philadelphia, PA; Department of Neonatology, Pennsylvania Hospital, Philadelphia, PA; Department of Pediatrics and Physiology, Temple University School of Medicine, Philadelphia, PA (MRW, THS); and the Nemours Lung Center, Alfred I. duPont Hospital for Children, Wilmington, DE
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Jeng MJ, Oliver R, Wolfson MR, Shaffer TH. Partial liquid ventilation: Effect of initial dose and redosing strategy in acute lung injury. Pediatr Crit Care Med 2002; 3:163-170. [PMID: 12780988 DOI: 10.1097/00130478-200204000-00014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE: Partial liquid ventilation (PLV) with perfluorochemicals has been shown to be effective in treating acute respiratory failure in animal studies and human trials. To determine the influences of perfluorochemicals on initial dose and redosing strategy, we studied their effects on gas exchange, pulmonary mechanics, and lung architecture. DESIGN: After lung injury was induced by repeated warm saline lavages, the animals were instilled endotracheally with different doses of perflubron during 5-10 mins in PLV-treated groups. The animals were randomized to five groups: PLV-12S (12 mL/kg perflubron, single dose), PLV-12M (12 mL/kg perflubron, multiple replacement doses), PLV-18S (18 mL/kg perflubron, single dose), PLV-18M (18 mL/kg perflubron, multiple replacement doses), and the control group (conventional mechanical ventilation only). Ventilator settings were kept constant during the 4-hr experiment. SETTING: An animal laboratory affiliated with Temple University School of Medicine. SUBJECTS: Twenty-eight New Zealand White juvenile rabbits (weight, 1.96 +/- 0.03 kg). INTERVENTIONS: Physiologic data were recorded every 30 mins. A constant volume (1.3 mL/kg/hr) of perflubron was replaced hourly in the PLV-12M and PLV-18M groups. The perflubron in the expired gas was measured with a thermal detector device. The hourly evaporative loss rate and the estimated residual perfluorochemical amount were calculated and analyzed. Histologic examinations of the lungs were performed. MEASUREMENTS AND MAIN RESULTS: All animals in the PLV-treated groups (PLV-12S, n = 4; PLV-12M, n = 5, PLV-18S, n = 5; PLV-18M, n = 4) demonstrated improvements in gas exchange and respiratory compliance that were significantly (p <.05) better than the control group (n = 8). However, the PLV-12S group demonstrated progressive deterioration after the initial improvement. The loss rate of perflubron did not differ among the PLV-treated groups (1.17 +/- 0.03 mL/kg/hr), but the residual perfluorochemical volume in the lungs decreased progressively and significantly in the PLV-12S and PLV-18S groups as a function of time (p <.05). Histologic examination showed good alveolar protection in the PLV-12M, PLV-18S, and PLV-18M groups. CONCLUSIONS: We conclude that the low initial dose (12 mL/kg, about two thirds the functional residual capacity volume of rabbits) of perflubron required hourly replacement to maintain the effects of PLV. With a high initial dose of 18 mL/kg perflubron (equal to a full functional residual capacity volume in rabbits), the responses are potentiated in both single and multiple dosing groups up to 4 hrs.
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Affiliation(s)
- Mei-Jy Jeng
- Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, Republic of China; and the Department of Pediatrics, Children's Medical Center, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China; the Division of Neonatology, Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA; the Departments of Physiology and Pediatrics, Temple University School of Medicine, Philadelphia, PA (MRW, THS); and the Nemours Lung Center, Alfred I. duPont Hospital for Children, Wilmington, DE. E-mail:
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Gastiasoro-Cuesta E, Alvarez-Díaz FJ, Arnaiz-Renedo A, Fernández-Ruanova B, López-de-Heredia-Y-Goya J, Román-Etxebarria L, Alfonso-Sánchez LF, Valls-i-Soler A. The cardiovascular effects of partial liquid ventilation in newborn lambs after experimental meconium aspiration. Pediatr Crit Care Med 2001; 2:334-9. [PMID: 12793937 DOI: 10.1097/00130478-200110000-00010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To study the effects of partial liquid ventilation with perfluorocarbon on cardiovascular function, pulmonary gas exchange, and lung mechanics in term newborn lambs with pulmonary hypertension induced by tracheal instillation of human meconium. DESIGN Prospective, randomized study. SETTING Research Unit at a university-affiliated hospital. SUBJECTS Twelve term newborn lambs (<6 days old). INTERVENTIONS Lambs were studied in two groups (n = 6): meconium aspiration (3-5 ml/kg 20% meconium solution) managed on pressure-limited conventional mechanical ventilation with or without partial liquid ventilation with perfluorocarbon. MEASUREMENTS AND MAIN RESULTS Heart rate, systemic and pulmonary arterial pressures, arterial pH and blood gases, cardiac output, and pulmonary mechanics were measured. Partial liquid ventilation in term newborn lambs with experimental meconium aspiration did not alter cardiovascular profile: heart rate, systemic arterial pressure, and cardiac output maintained initial values throughout the experiment. There was a significant improvement in gas exchange (oxygenation increased from values of <100 torr to 338 torr, and ventilation reached normal values in 15 mins). Dynamic compliance increased in 30 mins, reaching basal values (1.1 +/- 0.3 ml/cm H(2)O per kg). Despite the good response (blood gases and cardiovascular profile) to partial liquid ventilation in meconium aspiration syndrome, pulmonary hypertension did not decrease. CONCLUSIONS Partial liquid ventilation with perfluorocarbon could be a good noninvasive alternative technique that improves gas exchange and pulmonary mechanics in meconium aspiration syndrome without impairing cardiovascular function.
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Affiliation(s)
- E Gastiasoro-Cuesta
- Research Unit on Experimental Neonatal Respiratory Physiology, Department of Paediatrics, Hospital of Cruces and University of the Basque Country Medical School, Barakaldo, Bizkaia, Spain
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Larrabe JL, Alvarez FJ, Cuesta EG, Valls-i-Soler A, Alfonso LF, Arnaiz A, Fernández MB, Loureiro B, Publicover NG, Roman L, Casla JA, Gómez MA. Development of a time-cycled volume-controlled pressure-limited respirator and lung mechanics system for total liquid ventilation. IEEE Trans Biomed Eng 2001; 48:1134-44. [PMID: 11585037 DOI: 10.1109/10.951516] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Total liquid ventilation can support gas exchange in animal models of lung injury. Clinical application awaits further technical improvements and performance verification. Our aim was to develop a liquid ventilator, able to deliver accurate tidal volumes, and a computerized system for measuring lung mechanics. The computer-assisted, piston-driven respirator controlled ventilatory parameters that were displayed and modified on a real-time basis. Pressure and temperature transducers along with a lineal displacement controller provided the necessary signals to calculate lung mechanics. Ten newborn lambs (<6 days old) with respiratory failure induced by lung lavage, were monitored using the system. Electromechanical, hydraulic, and data acquisition/analysis components of the ventilator were developed and tested in animals with respiratory failure. All pulmonary signals were collected synchronized in time, displayed in real-time, and archived on digital media. The total mean error (due to transducers, analog-to-digital conversion, amplifiers, etc.) was less than 5% compared with calibrated signals. Components (tubing, pistons, etc.) in contact with exchange fluids were developed so that they could be readily switched, a feature that will be important in clinical settings. Improvements in gas exchange and lung mechanics were observed during liquid ventilation, without impairment of cardiovascular profiles. The total liquid ventilator maintained accurate control of tidal volumes and the sequencing of inspiration/expiration. The computerized system demonstrated its ability to monitor in vivo lung mechanics, providing valuable data for early decision making.
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Affiliation(s)
- J L Larrabe
- Department of Navigation Sciences, Engineers and Shipbuilders, High Technical School of Maritime Studies, Maria Diaz de Haro, Bizkaia, Spain.
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20
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Efficacy of Specific Perfluorocarbons for Use in Partial Liquid Ventilation. Crit Care Med 2001. [DOI: 10.1097/00003246-200104000-00060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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21
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Miller TF, Milestone B, Stern R, Shaffer TH, Wolfson MR. Effects of perfluorochemical distribution and elimination dynamics on cardiopulmonary function. J Appl Physiol (1985) 2001; 90:839-49. [PMID: 11181591 DOI: 10.1152/jappl.2001.90.3.839] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Based on a physicochemical property profile, we tested the hypothesis that different perfluorochemical (PFC) liquids may have distinct effects on intrapulmonary PFC distribution, lung function, and PFC elimination kinetics during partial liquid ventilation (PLV). Young rabbits were studied in five groups [healthy, PLV with perflubron (PFB) or with perfluorodecalin (DEC); saline lavage injury and conventional mechanical ventilation (CMV); saline lavage injury PLV with PFB or with DEC]. Arterial blood chemistry, respiratory compliance (Cr), quantitative computed tomography of PFC distribution, and PFC loss rate were assessed for 4 h. Initial distribution of PFB was more homogenous than that of DEC; over time, PFB redistributed to dependent regions whereas DEC distribution was relatively constant. PFC loss rate decreased over time in all groups, was higher with DEC than PFB, and was lower with injury. In healthy animals, arterial PO(2) (Pa(O(2))) and Cr decreased with either PFC; the decrease was greater and sustained with DEC. Lavaged animals treated with either PFC demonstrated increased Pa(O(2)), which was sustained with PFB but deteriorated with DEC. Lavaged animals treated with PFB demonstrated increased Cr, higher Pa(O(2)), and lower arterial PCO(2) than with CMV or PLV with DEC. The results indicate that 1) initial distribution and subsequent intrapulmonary redistribution of PFC are related to PFC properties; 2) PFC distribution influences PFC elimination, gas exchange, and Cr; and 3) PFC elimination, gas exchange, and Cr are influenced by PFC properties and lung condition.
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Affiliation(s)
- T F Miller
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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22
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Meinhardt JP, Quintel M, Hirschl RB. Development and application of a double-piston configured, total-liquid ventilatory support device. Crit Care Med 2000; 28:1483-8. [PMID: 10834700 DOI: 10.1097/00003246-200005000-00038] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Perfluorocarbon liquid ventilation has been shown to enhance pulmonary mechanics and gas exchange in the setting of respiratory failure. To optimize the total liquid ventilation process, we developed a volume-limited, time-cycled liquid ventilatory support, consisting of an electrically actuated, microprocessor-controlled, double-cylinder, piston pump with two separate limbs for active inspiration and expiration. DESIGN Prospective, controlled, animal laboratory study, involving sequential application of conventional gas ventilation, partial ventilation (PLV), and total liquid ventilation (TLV). SETTING Research facility at a university medical center. SUBJECTS A total of 12 normal adult New Zealand rabbits weighing 3.25+/-0.1 kg. INTERVENTIONS Anesthestized rabbits were supported with gas ventilation for 30 mins (respiratory rate, 20 cycles/min; peak inspiratory pressure, 15 cm H2O; end-expiratory pressure, 5 cm H2O), then PLV was established with perflubron (12 mL/kg). After 15 mins, TLV was instituted (tidal volume, 18 mL/kg; respiratory rate, 7 cycles/min; inspiratory/expiratory ratio, 1:2 cycles/min). After 4 hrs of TLV, PLV was re-established. MEASUREMENTS AND MAIN RESULTS Of 12 animals, nine survived the 4-hr TLV period. During TLV, mean values +/- SEM were as follows: PaO2, 363+/-30 torr; PaCO2, 39+/-1.5 torr; pH, 7.39+/-0.01; static peak inspiratory pressure, 13.2+/-0.2 cm H2O; static endexpiratory pressure, 5.5+/-0.1 cm H2O. No significant changes were observed. When compared with gas ventilation and PLV, significant increases occurred in mean arterial pressure (62.4+/-3.5 torr vs. 74.0+/-1.2 torr) and central venous pressure (5.6+/-0.7 cm H2O vs. 7.8+/-0.2 cm H2O) (p < .05). CONCLUSIONS Total liquid ventilation can be performed successfully utilizing piston pumps with active expiration. Considering the enhanced flow profiles, this device configuration provides advantages over others.
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Affiliation(s)
- J P Meinhardt
- Universitätsklinikum Mannheim, Fakultät für Klinische Medizin der Universität Heidelberg, Germany
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Al-Rahmani A, Awad K, Miller TF, Wolfson MR, Shaffer TH. Effects of partial liquid ventilation with perfluorodecalin in the juvenile rabbit lung after saline injury. Crit Care Med 2000; 28:1459-64. [PMID: 10834696 DOI: 10.1097/00003246-200005000-00034] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate the feasibility of using the perfluorochemical, perfluorodecalin, for partial liquid ventilation (PLV) with respect to gas exchange and lung mechanics in normal and saline-injured lungs of juvenile rabbits. DESIGN Experimental, prospective, randomized, controlled study. SETTING Physiology laboratory at a university medical school. SUBJECTS Seventeen juvenile rabbits assigned to three groups. INTERVENTIONS The conventional mechanical ventilation (CMV)-injury group (n = 5) was treated with CMV after establishing a lung injury; the PLV-injury group (n = 6) was treated with PLV after lung injury; and the PLV-healthy group (n = 6) was supported with PLV without lung injury. Lung injury was created by repeated saline lung lavages. PLV-treated animals received a single dose of intratracheal perfluorodecalin at a volume equal to the measured preinjury gas functional residual capacity (functional residual capacity = 18.6+/-1.5 [SEM] mL/kg). MEASUREMENTS AND MAIN RESULTS Sequential measurements of total respiratory compliance and arterial blood chemistries were performed in all groups. Oxygenation index (OI) and ventilation efficiency index were calculated. After lung injury, there was a significant (p < .05) decrease in PaO2, total respiratory compliance, and ventilation efficiency index and an increase in OI and PaCO2. In the PLV-injury group, PLV significantly (p < .05) improved PaO2 (+60%) and OI (-33%) over time. Compliance was significantly (p < .05) higher (90%) than in the CMV-injury group over time. CONCLUSIONS These results demonstrate that PLV with perfluorodecalin improved oxygenation and increased respiratory compliance in the saline-injured rabbit lung. In addition, similar to the effects of several other perfluorochemical liquids on normal lungs, pulmonary administration of perfluorodecalin was associated with a small impairment in gas exchange and a significant decrease in lung compliance in the juvenile rabbit model.
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Affiliation(s)
- A Al-Rahmani
- Department of Physiology, Temple University School of Medicine, Philadelphia, PA, USA
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24
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Cullen AB, Cox CA, Hipp SJ, Wolfson MR, Shaffer TH. Intra-tracheal delivery strategy of gentamicin with partial liquid ventilation. Respir Med 1999; 93:770-8. [PMID: 10603625 DOI: 10.1016/s0954-6111(99)90261-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Patients with pulmonary infection often present with ventilation and perfusion abnormalities, which can impair intravenous antibiotic therapy. Intra-tracheal (i.t.) administration has met with obstacles, such as inadequate delivery to affected lung regions and the disruption of gas exchange. We hypothesized that i.t. administration of a gentamicin (G)/perfluorochemical (PFC) suspension (G/PFC) would effectively deliver and distribute gentamicin to the lung, while maintaining gas exchange and non-toxic serum levels. In addition, we sought to compare serum G and lung levels and distribution of G when G/PFC is administered at the initiation of partial liquid ventilation (PLV) vs. during PLV. To test this hypothesis, 17 newborn lambs were ventilated by PLV with perflubron (LiquiVent) for 4 h using three different G (5 mg kg-1) administration techniques: i.t. slow-fill (SF) (n = 6; G/PFC over 15 min at start of PLV), i.t. top-fill (TF) (n = 6; G/PFC 10-65 min after start of PLV), intravenous (i.v.) (n = 5, aqueous injection at start of PLV). Serum levels of gentamicin were obtained 1, 15, 30 and 60 min after administration, and hourly there after for the remainder of the protocol (4 h). Arterial blood gas and pulmonary function measurements were obtained throughout the protocol. At the conclusion of the protocol, representative samples from each lung lobe, the brain and kidney were homogenized and assayed for gentamicin. All results are presented as the mean +/- SEM; P < 0.05. Over time, serum gentamicin levels were greatest (P < 0.05) in i.v. (11.0 +/- 2.3 micrograms ml-1), followed by TF (2.3 +/- 0.1 micrograms ml-1) and SF (0.8 +/- 0.1 microgram ml-1). The percentage of the administered dose remaining in the lungs after 4 h was greater (P < 0.05) following i.t. delivery (SF 23.8 +/- 4.3%, TF 13.7 +/- 2.5%) as compared to i.v. (3.7 +/- 0.5%). These findings suggest that for a given dose of G, both SF and TF delivery methods of G/PFC can enhance pulmonary, relative to systemic, antibiotic coverage.
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Affiliation(s)
- A B Cullen
- Temple University School of Medicine, Department of Physiology, Philadelphia, PA 19140, USA
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25
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Miller TF, Milestone B, Stern R, Shaffer TH, Wolfson MR. Effect of single versus multiple dosing on perfluorochemical distribution and elimination during partial liquid ventilation. Pediatr Pulmonol 1999; 27:410-8. [PMID: 10380093 DOI: 10.1002/(sici)1099-0496(199906)27:6<410::aid-ppul8>3.0.co;2-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to quantitate perfluorochemical (PFC) elimination kinetics during partial liquid ventilation (PLV) following an initial fill with or without hourly dosing. Young New Zealand rabbits were studied in two groups: Gr I (n = 6), PLV with a single dose of PFC liquid (perflubron: LiquiVent, Alliance Pharmaceutical Corp.); and Gr II (n = 5), PLV with PFC liquid and multiple hourly dosing . All rabbits were studied for 4 h, following initial instillation of a volume of PFC liquid equal to the measured gas functional residual capacity. Animals were ventilated at a constant breathing frequency (30 br/min), tidal volume (9.3+/-0.3 SE mL/kg), positive end expiratory pressure (4 cm H2O), and inspiratory time (0.30 s). PFC saturation of mixed expired gas (PFC-Sat) was assessed with a thermal conductivity analyzer, and PFC elimination was calculated from PFC-Sat, minute ventilation, and temperature of the expired gas. In GR II, PFC was supplemented hourly at a volume determined by PFC elimination calculations. The results demonstrated a decrease in PFC-sat and PFC loss with time, independent of group (P< 0.05). In addition, with hourly supplementation (GR II), PFC-Sat and PFC elimination over time was significantly (P < 0.05) greater than in animals (GR I) which did not receive additional doses. These data demonstrate that the PFC elimination rate is not constant and is related to the amount of PFC in the respiratory system. This may have occurred due to distributional differences of ventilation and PFC liquid between the single and multiple dosing groups. These findings also suggest that evaluation of PFC concentrations in expired gas may be a clinically useful index of intrapulmonary PFC distribution during PLV, and that maintained elevation of expired gas PFC saturation may guide optimal PFC dosing intervals and distribution to maximize protection against barotrauma.
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Affiliation(s)
- T F Miller
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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26
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Loer SA, Tarnow J. Effects of partial liquid ventilation with perfluorocarbons on pressure-flow relationships, vascular compliance, and filtration coefficients of isolated blood-perfused rabbit lungs. Crit Care Med 1998; 26:2037-41. [PMID: 9875917 DOI: 10.1097/00003246-199812000-00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES The density of perfluorocarbons is almost twice that of blood. Therefore, we hypothesized that partial liquid ventilation with these fluids markedly affects pulmonary hemodynamics and filtration coefficients. To test these hypotheses we studied pressure-flow relationships, vascular compliances, capillary pressures, and filtration coefficients in normal and perfluorocarbon-ventilated rabbit lungs. DESIGN Controlled animal study with an ex-vivo isolated lung preparation. SETTING Research laboratory for experimental anesthesiology at the Heinrich-Heine-University of Düsseldorf. SUBJECTS Fourteen New Zealand White rabbits. INTERVENTIONS The lungs were perfused under zone 3 flow conditions with autologous blood at various flow rates (50 to 250 mL/min, closed circuit, roller pump, 37 degrees C) and ventilated with 5% CO2 in air (positive end-expiratory pressure: 2 cm H2O, tidal volume: 10 mL/kg, respiratory rate: 30 breaths/min) without (control group, n=7) and with (n=7) perfluorocarbon administered intratracheally (15 mL/kg). MEASUREMENTS AND MAIN RESULTS Pulmonary arterial, left atrial, and airway pressures, as well as blood reservoir volume (reflecting changes in pulmonary blood volume) and lung weight, were measured continuously. Inconsistent with our hypothesis, we found no significant differences between both groups in the slopes and intercepts of the pressure-flow relationships. There were no significant differences in capillary pressures determined by double occlusion (6.7+/-1.2 vs. 6.3+/-1.3 cm H2O for control group, p=.53), vascular compliances (0.51+/-0.10 vs. 0.47+/-0.09 mL/cm H2O for control group, p=.38), and filtration coefficients (0.33+/-0.06 vs. 0.37+/-0.07 mL/min/mm Hg/100 g wet weight for control group, p=.80, Mann-Whitney). CONCLUSIONS Partial liquid ventilation with perfluorocarbons has no relevant effects on pulmonary filtration coefficients and global hemodynamic variables of isolated zone 3 lungs. These findings suggest that right ventricular afterload is not changed with partial liquid ventilation. It is likely, however, that intrapulmonary blood flow is redistributed toward less-dependent regions, although relevant global hemodynamic changes are absent during partial liquid ventilation.
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Affiliation(s)
- S A Loer
- Department of Experimental Anesthesiology, Heinrich-Heine-University of Düsseldorf, Germany
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27
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Kallas HJ. Non-conventional respiratory support modalities applicable in the older child. High frequency ventilation and liquid ventilation. Crit Care Clin 1998; 14:655-83. [PMID: 9891632 DOI: 10.1016/s0749-0704(05)70025-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
HFV, LV, and several other novel therapies offer promise to adults and children that the mortality associated with respiratory failure may be affected. Although there are several forms of HFV, HFOV is presently gaining favor in the treatment of severe respiratory failure and has generally supplanted HFJV in pediatric critical care. HFOV has the advantage of having an active expiratory phase, which helps to minimize air trapping and better modulate mean lung volume. Ventilators with sufficient power to perform HFOV in adults are currently under investigation, although there is a growing experience in using current ventilators in larger patients. To date, however, demonstration of lowered mortality with HFOV is lacking although intermediate outcome indicators are improved. PLV also offers promise in the treatment of ARF through its drastic ability to improve oxygenation, ventilation, and compliance in many lung injury models. Human trials are presently underway, but the optimal delivery of this novel therapy still necessitates extensive investigation. TLV is likely even more removed from general clinical application given the necessity of developing a new generation of ventilators for the delivery of liquid tidal volumes. How these and other modalities may piece together to improve the condition of our patients who have respiratory failure remains to be seen, but certainly, present and future investigation will be intriguing for years to come.
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Affiliation(s)
- H J Kallas
- Department of Pediatrics, University of California, Davis, School of Medicine, Sacramento, USA.
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Affiliation(s)
- M R Wolfson
- Temple University School of Medicine, Department of Physiology, Philadelphia, Pennsylvania 19140, USA.
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Tarczy-Hornoch P, Hildebrandt J, Standaert TA, Jackson JC. Surfactant replacement increases compliance in premature lamb lungs during partial liquid ventilation in situ. J Appl Physiol (1985) 1998; 84:1316-22. [PMID: 9516199 DOI: 10.1152/jappl.1998.84.4.1316] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Treatments available to improve compliance in surfactant-deficient states include exogenous surfactant (ES) and either partial (PLV) or total liquid ventilation (TLV) with perfluorochemical (PFC). Because of the additional air-lung and air-PFC interfaces introduced during PLV compared with TLV, we hypothesized that compliance would be worse during PLV than during TLV. Because surfactant is able to reduce interfacial tension between air and lung as well as between PFC and lung, we further hypothesized that compliance would improve with surfactant treatment before PLV. In excised preterm lamb lungs, we used Survanta for surfactant replacement and perflubron as the PFC. Compliance during PLV was intermediate between TLV and gas inflation, both with and without surfactant. Surfactant improved compliance during PLV, compared with PLV alone. Because of the force-balance equation governing the behavior of immiscible droplets on liquid surfaces, we predict that PFC droplets spread during PLV to cover the alveolar surface in surfactant-deficient lungs during most of lung inflation and deflation but that the PFC would retract into droplets in surfactant-sufficient lungs, except at end inspiration.
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Affiliation(s)
- P Tarczy-Hornoch
- Departments of Pediatrics, Medicine, and Physiology/Biophysics, University of Washington, Seattle, Washington 98195, USA.
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Wolfson MR, Kechner NE, Roache RF, DeChadarevian JP, Friss HE, Rubenstein SD, Shaffer TH. Perfluorochemical rescue after surfactant treatment: effect of perflubron dose and ventilatory frequency. J Appl Physiol (1985) 1998; 84:624-40. [PMID: 9475875 DOI: 10.1152/jappl.1998.84.2.624] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To test the hypotheses that perfluorochemical (PFC) liquid rescue after natural surfactant (SF) treatment would improve pulmonary function and histology and that this profile would be influenced by PFC dose or ventilator strategy, anesthetized preterm lambs (n = 31) with respiratory distress were studied using nonpreoxygenated perflubron. All animals received SF at 1 h and were randomized at 2 h as follows and studied to 4 h postnatal age: 1) conventional mechanical gas ventilation (n = 8), 2) 30 ml/kg perflubron with gas ventilation [partial liquid ventilation (PLV)] at 60 breaths/min (n = 8), 3) 10 ml/kg perflubron with PLV at 60 breaths/min (n = 7), and 4) 10 ml/kg perflubron with PLV at 30 breaths/min (n = 8). All animals tolerated instillation without additional cardiopulmonary instability. All perflubron-rescued groups demonstrated sustained improvement in gas exchange, respiratory compliance, and reduction in pressure requirements relative to animals receiving SF alone. Improvement was directly related to perflubron dose and breathing frequency; peak inspiratory pressure required to achieve physiological gas exchange was lower in the higher-dose and -frequency groups, and mean airway pressure was lower in the lower-frequency group. Lung expansion was greater and evidence of barotrauma was less in the higher-dose and -frequency group; regional differences in expansion were not different as a function of dose but were greater in the lower-frequency group. Regional differences in lung perflubron content were reduced in the higher-dose and -frequency groups and greatest in the lower-dose and -frequency group. The results suggest that, whereas PLV of the SF-treated lung improves gas exchange and lung mechanics, the protective benefits of perflubron in the lung may depend on dose and ventilator strategy to optimize PFC distribution and minimize exposure of the alveolar-capillary membrane to a gas-liquid interface.
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Affiliation(s)
- M R Wolfson
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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Stavis RL, Wolfson MR, Cox C, Kechner N, Shaffer TH. Physiologic, biochemical, and histologic correlates associated with tidal liquid ventilation. Pediatr Res 1998; 43:132-8. [PMID: 9432124 DOI: 10.1203/00006450-199801000-00020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tidal liquid ventilation (TLV) with perfluorochemical fluid (PFC) has been successfully used experimentally for up to 4 h. However, no studies of prolonged TLV have been reported. We hypothesized that full-term newborn lambs can safely and effectively be liquid-ventilated for up to 24 h. To test this hypothesis, 17 lambs were liquid-ventilated; 7 for 4 h, 5 for 12 h, and 5 for 24 h. Arterial blood samples were obtained for PFC uptake, lipid analysis, and blood gas measurements. Tissues were obtained for histologic and biochemical analysis. Arterial blood gas and mean arterial blood pressure were as follows (mean +/- SEM): pH 7.48 +/- 0.04; PaCO2 30.6 +/- 2.8; PaO2 424 +/- 17; mean arterial pressure 76 +/- 16 mm Hg. PFC blood levels increased rapidly to a mean of 5.2 +/- 3.9 microg/mL. PFC tissue levels increased significantly (p < 0.01) from 260 +/- 45 microg/g at 4 h to 400 +/- 140 microg/g at 12 h. There was no further increase in PFC tissue levels by 24 h (456 +/- 181 microg/g). There was a significant difference in PFC concentration as a function of tissue (p < 0.01). Furthermore, there was a significant correlation (r = 0.88; p < 0.01) between the amount of PFC and lipid in blood and tissue. Microscopic examination of the lungs demonstrated no evidence of barotrauma. These data demonstrate that prolonged TLV can be safe and efficacious for up to 24 h in full-term newborn lambs.
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Affiliation(s)
- R L Stavis
- Thomas Jefferson University Department of Pediatrics, The Bryn Mawr Hospital, Philadelphia, Pennsylvania 19107, USA
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Abstract
Liquid-assisted ventilation, as an alternative ventilation strategy for respiratory distress, is progressing from theory and basic science research to clinical application. Biochemically inert perfluorochemical liquids have low surface tension and high solubility for respiratory gases. From early immersion experiments, two primary techniques for liquid-assisted ventilation have emerged: total liquid ventilation and partial liquid ventilation. While computer-controlled, time-cycled, pressure/volume-limited total liquid ventilators can take maximum advantage of these liquids by completely eliminating the gas phase in the distressed lung, partial liquid ventilation takes advantage of having these liquids in the lung while maintaining gas ventilation. The benefits of both partial and total techniques have been demonstrated in animal models of neonatal and adult respiratory distress syndrome, aspiration syndromes and congenital diaphragmatic hernia and also in combination with other therapeutic modalities including extracorporeal membrane oxygenation, high-frequency ventilation and nitric oxide. Additionally, nonrespiratory applications have expanding potential including pulmonary drug delivery and radiographic imaging. Since its use in neonates in 1989, liquid-assisted ventilation in humans has progressed to a variety of clinical experiences with different aetiologies of respiratory distress. The future holds the opportunity to clarify and optimize the potential of multiple clinical applications for liquid-assisted ventilation.
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Affiliation(s)
- C M Weis
- Pennsylvania Hospital, Newborn Pediatrics, Philadelphia 19107, USA
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Neonatal intensive care. Acta Anaesthesiol Scand 1997. [DOI: 10.1111/j.1399-6576.1997.tb04894.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Meszaros E, Ogawa R. Continuous low-flow tracheal gas insufflation during partial liquid ventilation in rabbits. Acta Anaesthesiol Scand 1997; 41:861-7. [PMID: 9265929 DOI: 10.1111/j.1399-6576.1997.tb04801.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Both partial liquid ventilation (PLV) and tracheal gas insufflation are novel techniques for mechanical ventilation. In this study we examined whether PLV superimposed by continuous low-flow tracheal gas insufflation (TGI) offers any advantage to the blood gases and lung mechanics in normal-lung rabbits compared to the use of PLV only. METHODS Eighteen anesthetized, paralyzed and mechanically ventilated rabbits were used. After obtaining a baseline PaCO2 value between 29 and 39 mmHg (3.9 and 5.2 kPa), the animals were assigned to three equal groups according to the ventilation they received--A group: PLV superimposed by TGI; B group: PLV only; and C group: continuous mandatory ventilation (CMV) superimposed by TGI. Serial arterial blood gases, pH and lung mechanics were measured. RESULTS The animals in each group were hemodynamically stable. In the case of the A group, PaO2 continuously increased, and PaCO2 stabilized around 40.8 +/- 5.5 mmHg (5.4 +/- 0.7 kPa, mean +/- SD, NS). In the B group, the tendency for PaO2 to increase was not as definite; PaCO2 continuously increased from 35.2 +/- 2.3 mmHg (4.7 +/- 0.3 kPa) to 56.3 +/- 12.7 mmHg (7.5 +/- 1.7 kPa, P < 0.05) at the end of the experiment. In the C group, PaO2 and PaCO2 were stable during the observation period. The superimposition of TGI on PLV did not decrease the airway pressures compared to PLV alone. CONCLUSION In summary, continuous low-flow TGI superimposed on PLV can decrease and stabilize the PaCO2 elevation caused by the initiation of PLV.
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Affiliation(s)
- E Meszaros
- Department of Anesthesiology, Nippon Medical School, Tokyo, Japan
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35
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Fox WW, Cox CA, Weis CM, Wolfson MR, Shaffer TH. Comparison of perfluorochemical fluids used for liquid ventilation: effect of endotracheal tube flow resistance. Pediatr Pulmonol 1997; 23:449-56. [PMID: 9220528 DOI: 10.1002/(sici)1099-0496(199706)23:6<449::aid-ppul9>3.0.co;2-d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Neonatal endotracheal tubes with small inner diameters are associated with increased resistance regardless of the medium used for assisted ventilation. During liquid ventilation (LV) reduced interfacial tension and pressure drop along the airways result in lower alveolar inflation pressure compared with gas ventilation (GV). This is possible by optimizing liquid ventilation strategies to overcome the resistive forces associated with liquid density (rho) and viscosity (mu) of these fluids. Knowledge of the effect of rho, mu, and endotracheal tube (ETT) size on resistance is essential to optimize LV strategies. To evaluate these physical properties, three perfluorochemical (PFC) fluids with a range of kinematic viscosities (FC-75 = 0.82, LiquiVent = 1.10, APF-140 = 2.90) and four different neonatal ETT tubes (Mallincrokdt Hi-Lo Jet ID 2.5, 3.0, 3.5, and 4.0 mm) were studied. Under steady-state flow, flow and pressure drop across the ETTs were measured simultaneously. Resistance was calculated by dividing pressure drop by flow, and both pressure-flow and resistance-flow relationships were plotted. Also, pressure drop and resistance were each plotted as a function of kinematic viscosity at flows of 0.01 L.s-1 for all four ETT sizes. Data demonstrated a quadratic relationship with respect to pressure drop versus flow, and a linear relationship with resistance versus flow: both were significantly correlated (R = 0.92; P < 0.01) and were inversely related to ETT size. Additionally, there was a significant correlation between pressure drop or resistance and kinematic viscosity (R = 0.99; P < 0.01). For LV in neonates these data can be used to select the optimum ETT size and PFC liquid depending OR the chosen ventilation strategy.
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Affiliation(s)
- W W Fox
- Children's Hospital of Philadelphia, Division of Neonatology, Pennsylvania 19104, USA
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36
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Wolfson MR, Shaffer TH. Liquid-assisted ventilation: From concept to clinical application. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1084-2756(97)80006-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Costantino ML, Fiore GB. Liquid ventilation: a mathematical model of gas diffusion in the premature lung. Med Eng Phys 1997; 19:157-63. [PMID: 9203150 DOI: 10.1016/s1350-4533(96)00041-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The liquid ventilation (LV) technique was previously demonstrated to be a valuable alternative to ordinary gas ventilation, particularly for newborn patients with severely distressed lungs. This work describes a mathematical model of gas transfer phenomena occurring within the lungs of a preterm newborn baby ventilated with liquid perfluorocarbon (PFC) RM-101. The model was conceived in order to perform computer simulations of LV treatments. Its input parameters are tidal volume, respiratory frequency, oxygen and carbon dioxide tension in inlet PFC; its output data are the partial pressures of respiratory gases in the alveolar environment. Such values may be evaluated at any instant from the beginning of the treatment, in order to judge whether the therapy is able to meet the necessary conditions to arterialize properly the patient's venous blood. The model also enables optimisation procedures to be defined and performed. Quantitative results and graphs are supplied, with reference to the simulation of LV applied to a preterm newborn of 28 gestational weeks. The main results point out that a relatively short duration of initial transients is attainable (200 to 240 s) and that blood arterialization is possible even with low oxygen tension in inlet PFC (29.7 kPa (223 mmHg)).
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Affiliation(s)
- M L Costantino
- Dipartimento di Bioingegneria, Politecnico di Milano, Milan, Italy
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38
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Abstract
Liquid Ventilation with perfluorochemicals (PFC) violates many of our long-held assumptions about how the lung functions. However, the technique has been so successful in animal models of lung disease that it is currently being tested in clinical trials for the treatment of infant and acute (“adult”) respiratory distress syndrome in newborns, children, and adults. A common feature of both infant and acute respiratory distress syndromes is an inability of the lung's surfactant system to adequately lower surface tension, leading to regions of atelectasis. Liquid ventilation with PFC appears to ameliorate the disease process by lowering interfacial tension in the lung, opening regions of atelectasis, and improving gas exchange. To understand how gas exchange is successful during liquid ventilation requires careful re-evaluation of the assumptions underlying our current models of gas exchange physiology during normal gas ventilation. These assumptions must then be examined in light of the alterations in pulmonary physiology during liquid ventilation.
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Shaffer TH, Wolfson MR. Liquid ventilation: an alternative ventilation strategy for management of neonatal respiratory distress. Eur J Pediatr 1996; 155 Suppl 2:S30-4. [PMID: 8839744 DOI: 10.1007/bf01958078] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Perfluorochemical (PFC) liquids have great potential for biomedical use and the support of respiration. Currently, there are several commercially available PFC fluids which meet the physiochemical property requirements as well as purity specifications necessary to perform many of the discussed biomedical applications. Moreover, state-of-the-art fluorine chemistry should enable production of new PFC liquids uniquely sculptured relative to the proposed specific application (ie. vehicle for pulmonary delivery of drugs, a diluent for pulmonary lavage, a medium for respiratory gas exchange). In addition to PFC fluid requirements, there have been several techniques reported for liquid assisted ventilation. These methods include total liquid ventilation, liquid lavage, and partial liquid ventilation. The efficacy of these various techniques is under extensive investigation with respect to specific types of lung dysfunction. Liquid ventilation (LV) techniques have the potential to treat lung disease with less risk of barotrauma and provide the means for direct and uniform delivery of pulmonary agents to injured or dysfunctional sites in the lung. For LV to assume a role in clinical medicine it must be shown to be safe and effective with respect to other therapies or in combination with current therapies. Although the use of LV in animal and initial clinical studies has been impressive to date, better documentation of efficacy in human disease will be required. Further controlled multi-center clinical trials are warranted and are currently in progress.
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Affiliation(s)
- T H Shaffer
- Temple University School of Medicine, Department of Physiology and Pediatrics, Philadelphia, PA 19140, USA
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40
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Foust R, Tran NN, Cox C, Miller TF, Greenspan JS, Wolfson MR, Shaffer TH. Liquid assisted ventilation: an alternative ventilatory strategy for acute meconium aspiration injury. Pediatr Pulmonol 1996; 21:316-22. [PMID: 8726157 DOI: 10.1002/(sici)1099-0496(199605)21:5<316::aid-ppul7>3.0.co;2-k] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Evidence of surfactant inactivation by meconium has led to the use of exogenous surfactant therapy in the management of meconium aspiration syndrome (MAS). Liquid assisted ventilation has been shown to improve the cardiopulmonary function in lungs with high surface tension. We compared exogenous surfactant therapy with liquid assisted ventilation in the management of experimental acute meconium aspiration injury. Thirty-two newborn lambs were ventilated at peak inspiratory pressures of 13-16 cm H2O, positive end expiratory pressure of 3-4 cm H2O, fractional inspired oxygen concentration (FiO2) of 1.0, and a respiratory frequency range between 30 and 35 breaths/min. Baseline arterial blood gases, pulmonary function, and arterial blood pressure measurements were taken. All lambs were given 2-3 ml/kg of an unfiltered 25% meconium solution. Lambs were then randomized into either gas-ventilated meconium control, or one of three treatment groups: 1) surfactant; 2) partial liquid ventilation (PLV); or 3) total liquid ventilation (TLV) for 4 hours after meconium injury. All treated groups demonstrated a significant increase in arterial oxygenation (P < 0.05); surfactant and PLV-treated lambs demonstrated significantly decreased arterial PCO2 (P < 0.05). Compliance in all groups increased compared with injury values; compliance of the TLV group increased more than in all other treatment groups (P < 0.05). In addition, lung histology of the TLV group demonstrated clear, intact alveolar epithelium and homogeneously expanded alveoli, while no such improvement was evident in the other groups. These data suggest roles for both exogenous surfactant therapy and liquid assisted ventilation techniques in the management of MAS.
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Affiliation(s)
- R Foust
- Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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41
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Overbeck MC, Pranikoff T, Hirschl RB. Partial liquid ventilation provides effective gas exchange in a large animal model. J Crit Care 1996; 11:37-42. [PMID: 8904282 DOI: 10.1016/s0883-9441(96)90018-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PURPOSE The purpose of this study was to show the ability of partial liquid ventilation (PLV) to sustain gas exchange in normal large (50 to 70 kg) adult animals. METHODS Ten adult sheep (53.7 +/- 2.8 kg) were anesthetized and mechanically ventilated. Sequential dosing of perflubron (LiquiVent, Alliance Pharmaceutical Corp, San Diego, CA) was performed to cumulative doses of 10 mL/kg, 20 mL/kg, 40 mL/kg, and 60 mL/kg. Physiological data were assessed at baseline and after each dose. Five animals were rotated through the left decubitus, right decubitus, supine, and prone positions while five animals remained prone throughout the experiment. RESULTS PaO2 and PaCO2 did not change significantly from baseline during administration of perflubron except for the PaO2 in rotated animals when supine (rotated-supine PaO2: baseline = 519 +/- 64 mm Hg; 60 mL/kg = 380 +/- 109 mm Hg, P = .0131). In both groups, static lung compliance (CT) decreased steadily with each successive perflubron instillation (nonrotated CT: baseline = 1.55 +/- 0.22 mL/cm H2O/kg; 60 mL/kg = 0.52 +/- 0.10 ml/cmH2O/kg, P = .0003). CONCLUSIONS These data show that during PLV in this normal animal model, effective gas exchange is sustained and CT decreases with increasing perflubron dose.
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Affiliation(s)
- M C Overbeck
- University of Michigan, Department of Surgery, Ann Arbor, USA
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Papo MC, Paczan PR, Fuhrman BP, Steinhorn DM, Hernan LJ, Leach CL, Holm BA, Fisher JE, Kahn BA. Perfluorocarbon-associated gas exchange improves oxygenation, lung mechanics, and survival in a model of adult respiratory distress syndrome. Crit Care Med 1996; 24:466-74. [PMID: 8625636 DOI: 10.1097/00003246-199603000-00017] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE To compare the effectiveness of perfluorocarbon-associated gas exchange to volume controlled positive pressure breathing in supporting gas exchange, lung mechanics, and survival in an acute lung injury model. DESIGN A prospective, randomized study. SETTING A university medical school laboratory approved for animal research. SUBJECTS Neonatal piglets. INTERVENTIONS Eighteen piglets were randomized to receive perfluorcarbon-associated gas exchange with perflubron (n=10) or volume controlled continuous positive pressure breathing (n=8) after acute lung injury was induced by oleic acid infusion (0.15 mL/kg iv). MEASUREMENTS AND MAIN RESULTS Arterial and venous blood gases, hemodynamics, and lung mechanics were measured every 15 mins during a 3-hr study period. All animals developed a metabolic and a respiratory acidosis during the infusion of oleic acid. Following randomization, the volume controlled positive pressure breathing group developed a profound acidosis (p<.05), while pH did not change in the perfluorocarbon-associated gas exchange group. Within 15 mins of initiating perfluorocarbon-associated gas exchange, oxygenation increased from a PaO2 of 52 +/- 12 torr (6.92 +/- 1.60 kPa) to 151 +/- 93 torr (20.0 +/- 12.4 kPa) and continued to improve throughout the study (p<.05). Animals that received volume controlled positive pressure breathing remained hypoxic with no appreciable change in PaO2. Although both groups developed hypercarbia during oleic acid infusion, PaCO2, steadily increased over time in the control group (p<.01). Static lung compliance significantly increased postrandomization (60 mins) in the animals supported by perflurocarbon-associated gas exchange (p<.05), whereas it remained unchanged over time in the volume controlled positive pressure breathing group. However, survival was significantly higher in the perfluorocarbon-associated gas exchange group with eight (80%) of ten animals surviving the entire study period. Only two (25%) of the eight animals in the volume controlled positive pressure breathing group were alive at the end of the study period (log-rank statistic, p=.013). CONCLUSIONS Perflurocarbon-associated gas exchange enhanced gas exchange, pulmonary mechanics, and survival in this model of acute lung injury.
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Affiliation(s)
- M C Papo
- Division of Pediatric Critical Care Medicine, Children's Hospital of Buffalo (SUNY), New York 14222, USA
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43
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Leach CL, Holm B, Morin FC, Fuhrman BP, Papo MC, Steinhorn D, Hernan LJ. Partial liquid ventilation in premature lambs with respiratory distress syndrome: efficacy and compatibility with exogenous surfactant. J Pediatr 1995; 126:412-20. [PMID: 7869204 DOI: 10.1016/s0022-3476(95)70461-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To determine the efficacy of partial liquid ventilation (PLV) by means of a medical-grade perfluorochemical liquid, perflubron (LiquiVent), in premature lambs with respiratory distress syndrome (RDS). Further, to determine the compatibility of perflubron with exogenous surfactant both in vitro and in vivo during PLV. DESIGN Prospective, randomized, controlled study, with in vitro open comparison. SUBJECTS Twenty-two premature lambs with RDS. INTERVENTIONS In vitro assays were conducted on three exogenous surfactants before and after combination with perflubron. We studied four groups of lambs, which received one of the following treatment strategies: conventional mechanical ventilation (CMV); surfactant (Exosurf) plus CMV; PLV; or surfactant plus PLV. MEASUREMENTS AND MAIN RESULTS In vitro surface tension, measured for three exogenous surfactants, was unchanged in each animal after exposure to perflubron. Lung mechanics and arterial blood gases were serially measured. All animals treated with PLV survived the 5 hours of experiment without complication; several animals treated with CMV died. During CMV, all animals had marked hypoxemia and hypercapnia. During PLV, arterial oxygen tension increased sixfold to sevenfold within minutes of initiation, and this increase was sustained; arterial carbon dioxide tension decreased to within the normal range. Compliance increased fourfold to fivefold during PLV compared with CMV. Tidal volumes were increased during PLV, with lower mean airway pressure. Resistance was similar for both CMV and PLV; there was no difference with surfactant treatment. CONCLUSIONS We conclude that PLV with perflubron improves lung mechanics and gas exchange in premature lambs with RDS, that PLV is compatible with exogenous surfactant therapy, and that, as a treatment for RDS in this model, PLV is superior to the surfactant studied.
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Affiliation(s)
- C L Leach
- Department of Pediatrics, Children's Hospital of Buffalo, State University of New York
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Hernan LJ, Fuhrman BP, Papo MC, Steinhorn DM, Leach CL, Salman N, Paczan PR, Kahn B. Cardiorespiratory effects of perfluorocarbon-associated gas exchange at reduced oxygen concentrations. Crit Care Med 1995; 23:553-9. [PMID: 7874909 DOI: 10.1097/00003246-199503000-00022] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To determine whether reducing FIO2 during perfluorocarbon-associated gas exchange would cause deterioration of hemodynamics, lung mechanics, or gas exchange in normal piglets. DESIGN A prospective, controlled animal trial. SETTING Experimental animal laboratory in a university setting. SUBJECTS Twelve normal, anesthetized piglets, 7 to 14 days old, and weighing 3.31 +/- 0.75 kg. INTERVENTIONS After the induction of anesthesia, tracheostomy and catheterization, piglets were stabilized. They were mechanically ventilated with a tidal volume of 15 mL/kg, inspiratory time of 25%, positive end-expiratory pressure of 4 cm H2O, and a respiratory rate of 20 to 28 breaths/min to obtain a baseline PaCO2 between 34 and 45 torr (4.7 and 6.0 kPa). Each animal was studied during continuous positive-pressure breathing, and during perfluorocarbon-associated gas exchange. They were ventilated at an FIO2 of 1.0 for 15 mins. FIO2 was randomly varied among 0.75, 0.5, and 0.3 every 15 mins, then returned to 1.0. At each FIO2, measurements of gas exchange, lung mechanics, and hemodynamics were made. After continuous positive-pressure breathing, perfluorocarbon-associated gas exchange was instituted by replacing the gaseous functional residual capacity of the lungs with perfluorooctylbromide. Animals were then ventilated and measurements were taken. MEASUREMENTS AND MAIN RESULTS At each FIO2, measurements of gas exchange (arterial blood gases and saturation), lung mechanics (mean airway pressure, static end-inspiratory pressure, and peak inspiratory pressure), and hemodynamics (heart rate, and mean arterial, right atrial, pulmonary artery occlusion, and pulmonary arterial pressures) were recorded. In six piglets, cardiac output was measured at each FIO2 by thermodilution. Cardiac index, indexed oxygen delivery and consumption, and indexed pulmonary vascular resistance were derived using standard formulas. Piglets were well saturated at all FIO2 settings during continuous positive-pressure breathing. However, during perfluorocarbon-associated gas exchange, arterial saturation decreased to 72% at an FIO2 of 0.3. Cardiac index and oxygen consumption were not affected by reducing FIO2 during perfluorocarbon-associated gas exchange, and were not significantly different than during continuous positive-pressure breathing. Oxygen delivery was reduced at an FIO2 of 0.3 during perfluorocarbon-associated gas exchange, but oxygen consumption remained in the flow independent portion of the curve despite arterial desaturation. Pulmonary arterial pressure was higher during perfluorocarbon-associated gas exchange than during continuous positive-pressure breathing. Pulmonary arterial pressure and indexed pulmonary vascular resistance were significantly higher during perfluorocarbon-associated gas exchange at an FIO2 of 0.3 than at any other FIO2 settings. CONCLUSIONS Piglets showed no adverse effects on lung mechanics during perfluorocarbon-associated gas exchange. Hemodynamics were well supported at all FIO2 settings, and arterial blood was fully oxygenated during perfluorocarbon-associated gas exchange at an FIO2 of > or = 0.5.
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Abstract
Studies in preterm animals and humans have shown that liquid ventilation is a potential alternative mode of support for neonates with respiratory failure. Perfluorochemicals have a high solubility for respiratory gases and can be instilled in the lung using lower pressures than with gas ventilation. Other potential advantages of liquid ventilation include decreased alveolar surface tension, improved pulmonary mechanics, alveolar recruitment, and the removal of pulmonary debris. This article describes in detail what liquid ventilation is, compares the physiologic effects of liquid ventilation to gas ventilation, and presents the nursing implications of this technique. A review of the recent literature on the subject is presented, including reports of laboratory and clinical experience with liquid ventilation.
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Affiliation(s)
- R Eanes
- Thomas Jefferson University Hospital, Philadelphia, USA
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Hirschl RB, Merz SI, Montoya JP, Parent A, Wolfson MR, Shaffer TH, Bartlett RH. Development and application of a simplified liquid ventilator. Crit Care Med 1995; 23:157-63. [PMID: 8001367 DOI: 10.1097/00003246-199501000-00025] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Perfluorocarbon liquid ventilation has been shown to have advantages over conventional gas ventilation in premature newborn and lung-injured animals. To simplify the process of liquid ventilation, we adapted an extra-corporeal life-support circuit as a time-cycled, volume-limited liquid ventilator. DESIGN Laboratory study that involved sequential application of gas and liquid ventilation in normal cats and in lung-injured sheep. SETTING A research laboratory at a university medical center. SUBJECTS Eight normal cats weighing 2.7 to 3.8 kg (mean 3.1 +/- 0.5), and four lung-injured young sheep weighing 10.4 to 22.5 kg (mean 15.9 +/- 5.0). INTERVENTIONS Normal cats were supported with traditional gas ventilation for 1 hr (respiratory rate 20 breaths/min, peak inspiratory pressure 12 cm H2O, positive end-expiratory pressure 4 cm H2O, and FIO2 1.0). The lungs were then filled with perfluorocarbon (30 mL/kg) and tidal volume liquid ventilation was instituted, utilizing a newly developed liquid ventilation device. Liquid ventilatory settings were 4 secs for inspiration time, 8 secs for expiration time, 5 breaths/min for respiratory rate, and 15 to 20 mL/kg for tidal volume. Liquid ventilation utilizing this device was also applied to sheep after induction of severe lung injury by right atrial injection of 0.07 mL/kg of oleic acid, followed by saline pulmonary lavage. Extracorporeal life support was instituted to provide a stable model of lung injury. For the first 30 mins of extracorporeal support, all animals were ventilated with gas. Animals were then ventilated with 15 mL/kg of perfluorocarbon over the ensuing 2.5 hrs. MEASUREMENTS AND MAIN RESULTS In normal cats, mean PaO2 values after 1 hr of liquid or gas ventilation were 275 +/- 90 (SD) torr (36.7 +/- 10.4 kPa) in the liquid-ventilated animals and 332 +/- 78 torr (44.3 +/- 10.4 kPa) in the gas-ventilated animals (NS). Mean PaCO2 values were 40.5 +/- 5.7 torr (5.39 +/- 0.31 kPa) in the liquid-ventilated animals and 37.6 +/- 2.3 torr (5.01 +/- 0.31 kPa) in the gas-ventilated animals (NS). Mean arterial pH values were 7.35 +/- 0.07 in the liquid-ventilated animals and 7.34 +/- 0.04 in the gas-ventilated animals (NS). No significant changes in heart rate, mean arterial pressure, lung compliance, or right atrial venous oxygen saturation were observed during liquid ventilation when compared with gas ventilation. In the lung-injured sheep, an increase in physiologic shunt from 15 +/- 7% to 66 +/- 9% was observed with induction of lung injury during gas ventilation. Liquid ventilation resulted in a significant reduction in physiologic shunt to 31 +/- 10% (p < .001). In addition, the extracorporeal blood flow rate required to maintain the PaO2 in the 50 to 80 torr (6.7 to 10.7 kPa) range was substantially and significantly (p < .001) lower during liquid ventilation than during gas ventilation (liquid ventilation 15 +/- 5 vs. gas ventilation 87 +/- 15 mL/min/kg). CONCLUSIONS Liquid ventilation can be performed successfully utilizing this simple adaptation of an extracorporeal life-support circuit. This modification to an existing extracorporeal circuit may allow other centers to apply this new investigational method of ventilation in the laboratory or clinical setting.
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Affiliation(s)
- R B Hirschl
- Department of Surgery, University of Michigan, Ann Arbor
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47
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Abstract
Mortality in acute respiratory failure in the non-neonatal pediatric patient has not changed substantially in 20 years, despite advances and refinements in conventional therapeutic strategies and technology. A host of innovative therapies are currently in various stages of investigation, including high frequency ventilation, pressure control ventilation, permissive hypercapnia, extracorporeal membrane oxygenation, exogenous surfactant administration, inhaled nitric oxide, and liquid ventilation. While none of these therapies has yet been prospectively studied in non-neonatal pediatric patients, all show much promise by virtue of their emphasis on either directly addressing pathophysiologic derangements associated with acute respiratory failure or by reducing the complications associated with conventional therapy.
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Affiliation(s)
- J C Ring
- Department of Pediatrics, University of Tennessee, Memphis
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Shaffer TH, Wolfson MR, Greenspan JS, Rubenstein SD, Stern RG. Perfluorochemical liquid as a respiratory medium. ARTIFICIAL CELLS, BLOOD SUBSTITUTES, AND IMMOBILIZATION BIOTECHNOLOGY 1994; 22:315-26. [PMID: 8087249 DOI: 10.3109/10731199409117423] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The use of perfluorochemical (PFC) liquids to facilitate or support respiration has been under study for several decades. The low surface tension and high respiratory gas solubility of liquid PFC enable adequate oxygenation and carbon dioxide removal at low insufflation pressures relative to gas ventilation in the immature or injured lung. Because liquid ventilation homogeneously inflates the lung and improves V/Q matching it has been studied as a vehicle for delivering biologically active agents to the lung tissues and systemic circulation. More recently, we have shown the utility of highly opaque PFC liquids as a high resolution computed tomographic (HRCT) bronchographic contrast agent either during LV or gas breathing after tracheal instillation of small quantities of PFC. As a result of extensive experimental work in premature animals as well as lung injury models, liquid PFC ventilation has been recently implemented as an investigational therapy for severe respiratory distress in human infants. This manuscript summarizes the physiological principles and applications of LV as well as the results of initial investigational clinical studies in human neonates with severe respiratory distress.
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Affiliation(s)
- T H Shaffer
- Department of Physiology, Temple University School of Medicine, Philadelphia, PA
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Curtis SE, Tilden SJ, Bradley WE, Cain SM. Effect of continuous rotation on the efficacy of partial liquid (perflubron) breathing in canine acute lung injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 361:449-56. [PMID: 7597969 DOI: 10.1007/978-1-4615-1875-4_79] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- S E Curtis
- Department of Pediatrics, University of Alabama at Birmingham 35294-0005, USA
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Curtis SE, Peek JT. Effects of progressive intratracheal administration of perflubron during conventional gas ventilation in anesthetized dogs with oleic acid lung injury. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1994; 345:51-8. [PMID: 8079752 DOI: 10.1007/978-1-4615-2468-7_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- S E Curtis
- Department of Pediatrics, University of Alabama at Birmingham 35294-0005
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