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Tawfic QA, Kausalya R. Liquid ventilation. Oman Med J 2011; 26:4-9. [PMID: 22043370 DOI: 10.5001/omj.2011.02] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 11/23/2010] [Indexed: 11/03/2022] Open
Abstract
Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV) is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future.
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Affiliation(s)
- Qutaiba A Tawfic
- Department of Anesthesiology and Intensive Care, Sultan Qaboos University Hospital, Muscat, Sultanate of Oman
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Abstract
Drug delivery to the diseased lung is hindered by the buildup of fluid and shunting of blood flow away from the site of injury. The use of perfluorocarbon compounds (PFCs) as drug delivery vehicles has been proposed to overcome these obstacles. This drug delivery approach is based on the unique properties of PFCs. For example, PFCs can homogeneously fill the lung and recruit airways by replacing edematous fluid. Analogously, drugs administered with a PFC vehicle are expected to be homogeneously distributed throughout the lung. At the same time, intrapulmonary administration of the drug will achieve higher drug concentrations in the lung than conventional approaches, while reducing systemic exposure. Unfortunately, PFCs are poor solvents for typical drug molecules. To overcome this obstacle, several approaches, such as dispersions, prodrugs, solubilizing agents and (micro)emulsions, are under investigation to develop homogeneous PFC-drug mixtures suitable for intrapulmonary administration.
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Affiliation(s)
- Hans-Joachim Lehmler
- Research Scientist, University of Iowa, Department of Occupational and Environmental Health, Iowa City, IA 52242, USA.
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Hwang JH, Kwon YS, Kang EH, Koh WJ, Kang KW, Kim HC, Chung MP, Kim H, Kwon OJ, Suh GY. Prone positioning improves oxygenation without adverse hemodynamic effects during partial liquid ventilation in a canine model of acute lung injury. Korean J Intern Med 2004; 19:237-42. [PMID: 15683112 PMCID: PMC4531571 DOI: 10.3904/kjim.2004.19.4.237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Partial liquid ventilation (PLV) and prone positioning can improve the arterial oxygenation (PaO2) in acute lung injury (ALI). We evaluated the effect of prolonged prone positioning during partial liquid ventilation (PLV) in a canine model of acute lung injury. METHODS Six mongrel dogs (weighing 17.4 +/- 0.7 kg each) were anesthetized, intubated and mechanically ventilated. After 1 hour of baseline stabilization, the dogs' lungs were instilled with 40 mL/kg perfluorocarbon (PFC). PLV was first performed in the supine position for 1 hour (S1), then in the prone position for 3 hours with hourly measurements (P1, P2, P3), and finally, PLV was performed with the animal turned back to the supine position for 1 hour (S2). RESULTS After instillation of the PFC, the PaO2 significantly increased from 992 +/- 32.6 mmHg at baseline to 198.1 +/- 59.2 mmHg at S1 (p = 0.001). When the dogs were turned to the prone position, the PaO2 further increased to 288.3 +/- 80.9 mmHg at P1 (p = 0.008 vs. S1): this increase was maintained for 3 hours, but the PaO2 decreased to 129.4 +/- 62.5 mmHg at S2 (p < 0.001 vs. P3). Similar changes were seen in the shunt fraction. There were no significant differences for the systemic hemodynamic parameters between the prone and supine positions. CONCLUSION Prolonged prone positioning during PLV in an animal model of ALI appears to improve oxygenation without any hemodynamic compromise.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Gee Young Suh
- Correspondence to : Gee Young Suh, M.D., Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Gangnam-gu, Seoul 135-710, Korea, Tel : 82-2-3410-3429, FAX : 82-2-3410-3849, E-mail :
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Crimi E, Slutsky AS. Inflammation and the acute respiratory distress syndrome. Best Pract Res Clin Anaesthesiol 2004; 18:477-92. [PMID: 15212340 DOI: 10.1016/j.bpa.2003.12.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Acute respiratory distress syndrome (ARDS) is a clinical syndrome of non-cardiogenic pulmonary oedema associated with bilateral pulmonary infiltrates, stiff lungs and refractory hypoxaemia. ARDS is characterized by an explosive acute inflammatory response in the lung parenchyma, leading to alveolar oedema, decreased lung compliance and, ultimately, hypoxaemia. Although our understanding of the causes and pathophysiology of ARDS has increased, the mortality rate remains in the range of 30-50%. No major advances in pharmacological therapy have been achieved. Mechanical ventilation is the main therapeutic intervention in the management of ARDS. The only approach that has been shown to reduce the inflammatory response and mortality is the use of lung-protective ventilatory strategy with a low tidal volume and high positive-end expiratory pressure. This chapter will review the current state of the literature on the pathogenesis of ARDS and ventilatory and pharmacotherapy approaches to its management.
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Affiliation(s)
- Ettore Crimi
- Division of Respiratory Medicine, Department of Critical Care Medicine, St Michael's Hospital, University of Toronto, Toronto, Ont., Canada
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Dani C, Costantino ML, Martelli E, Corno C, Fiore GB, Buonocore G, Longini M, Di Filippo A, Tozzini S, Rubaltelli FF. Perfluorocarbons attenuate oxidative lung damage. Pediatr Pulmonol 2003; 36:322-9. [PMID: 12950046 DOI: 10.1002/ppul.10368] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this study was to investigate the effect of tidal liquid ventilation (TLV) compared to conventional mechanical ventilation (CMV) on oxidative lung damage in the setting of acute respiratory distress syndrome (ARDS). After repeated lung lavages, 10 minipigs were treated with CMV or TLV for 4 hr before the animals were sacrificed. Samples for blood gas analysis and bronchial aspirate samples were withdrawn before the induction of lung injury, and at 10 min, 2 hr, and 4 hr after the beginning of ventilatory support. To assess lung oxidative damage, total hydroperoxide (TH) and advanced oxidation protein product (AOPP) concentrations were measured in bronchial aspirate samples. After 2 and 4 hr of ventilatory support, partial oxygen tension (PaO(2)) and base excess (BE) were significantly higher in the TLV group than in the CMV group, while PaCO(2) was slightly higher, but with no statistical significance. In the CMV group, the AOPP level was significantly higher at 4 hr than at baseline. TH and AOPP bronchial aspirate concentrations were higher in the CMV group than in the TLV group at 2 and 4 hr of ventilation. We conclude that animals treated with TLV showed lower oxidative lung damage compared to animals treated with CMV.
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Affiliation(s)
- C Dani
- Division of Neonatology, Careggi University Hospital of Florence, University of Florence School of Medicine, Viale Morgagni 85, 50134 Florence, Italy.
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Matsuda K, Sawada S, Bartlett RH, Hirschl RB. Effect of ventilatory variables on gas exchange and hemodynamics during total liquid ventilation in a rat model. Crit Care Med 2003; 31:2034-40. [PMID: 12847401 DOI: 10.1097/01.ccm.0000075353.38441.45] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES To investigate the settings necessary to achieve maximum gas exchange and pulmonary function while minimizing effects on cardiovascular hemodynamics during total liquid ventilation with a pressure-limited, time-cycled ventilator in a rat model. DESIGN Prospective, randomized controlled animal study. SETTING A university research laboratory. SUBJECTS Male Sprague-Dawley rats (n = 48). INTERVENTIONS All animals had a tracheostomy tube designed for total liquid ventilation placed under anesthesia. The carotid artery was cannulated for blood pressure monitoring and for assessing blood gas data. MEASUREMENTS AND MAIN RESULTS Forty 492 +/- 33 g rats were assigned to one of four inspiratory/expiratory ratio groups (inspiratory/expiratory ratio of 1:2, 1:2.5, 1:3, and 1:4). Total liquid ventilation was performed with a pressure-limited, time-cycled total liquid ventilator. Outcome measures were evaluated as a function of respiratory rate and included tidal volume, maximal alveolar ventilation, inspiratory and expiratory mean arterial pressures, the difference of mean arterial pressure between the inspiratory and expiratory phase, static end-inspiratory/expiratory pressures, Paco(2), Pao(2), tidal volume + approximate expiratory reserve volume, and lung volume-induced suppression of mean arterial pressure. Maximal alveolar ventilation increased and decreased in parabolic fashion as a function of respiratory rate and was maximal at rates of 4.3-6.8 breaths/min and high inspiratory/expiratory ratios that corroborated with optimal levels of Pao(2) and Paco(2). Lung overdistention occurred at high respiratory rates and high inspiratory/expiratory ratios. Deleterious effects were observed on the difference of mean arterial pressure between the inspiratory and expiratory phase during total liquid ventilation at low respiratory rates, apparently due to increased tidal volume, and on suppression of mean arterial pressure at high inspiratory/expiratory ratios and high respiratory rate apparently due to "auto-positive end-expiratory pressure." These effects were minimized in this model at respiratory rates >/=5.7 and </=6.8 breaths/min and inspiratory/expiratory ratios </=1:2.5. These settings were successfully tested in eight additional animals. CONCLUSION These data demonstrate the feasibility of performing total liquid ventilation in rodents. A balance must be identified where gas exchange is optimal yet hemodynamics are least affected. In the specific system studied, an inspiratory/expiratory ratio of 1:2.5 and respiratory rate of 6.8 breaths/min appeared to provide optimal gas exchange while minimizing the effects on hemodynamics.
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Affiliation(s)
- Kenichi Matsuda
- Department of Surgery, University of Michigan, Ann Arbor, USA
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Affiliation(s)
- U Kaisers
- Klinik für Anästhesiologie und Intensivmedizin, Charité-Campus Virchow-Klinikum, Med. Fakultät der Humboldt Universität zu Berlin, Germany
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Corno C, Fiore GB, Martelli E, Dani C, Costantino ML. Volume controlled apparatus for neonatal tidal liquid ventilation. ASAIO J 2003; 49:250-8. [PMID: 12790372 DOI: 10.1097/01.mat.0000065375.16706.ff] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Conventional gas ventilation is often unsuccessful for premature neonatal patients suffering from respiratory distress syndrome (RDS). For such patients, liquid ventilation (LV) with perfluorocarbon (PFC) liquids has been proposed. By eliminating the air-liquid interface in saccules (the premature gas exchange structures), where scarce or absent surfactant production exists, pulmonary instability is avoided, lung compliance is improved, and atelectatic saccules are recruited, ultimately lowering the saccular pressure. Tidal LV involves administrating a liquid tidal volume to the patient at each respiratory cycle, and therefore requires a dedicated circuital setup to deliver, withdraw, and refresh the PFC during the treatment. We have developed a prototype liquid breathing system (LBS). The apparatus comprises two subcircuits managed by a personal computer based control system. The ventilation subcircuit performs inspiration/expiration with two sets of peristaltic pumps. A system to evaluate the true inspired/expired volumes was devised that consists of two reservoirs equipped with pressure transducers measuring the hydraulic head of the fluid therein. Volume accuracy was +/- 0.3 ml. The refresh subcircuit properly processes the PFC by performing filtration (DFA, Pall, NY), oxygenation, CO2 scavenge, and heat exchange (SciMed 2500, Life Systems, MN). The new apparatus has been used in preliminary animal tests on five newborn mini pigs with induced acquired RDS. The PFC used was RM-101 (Miteni, Milano, Italy). The animals were successfully supported for 4 hours each. Mean arterial O2 pressure was 131.4 mm Hg (range 79.0-184.2), and mean arterial CO2 pressure was 64.8 mm Hg (range 60.0-73.4).
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Affiliation(s)
- Chiara Corno
- Dipartimento di Bioingegneria, Politecnico di Milano, Milan, Italy
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Cordingley JJ, Keogh BF. The pulmonary physician in critical care. 8: Ventilatory management of ALI/ARDS. Thorax 2002; 57:729-34. [PMID: 12149536 PMCID: PMC1746415 DOI: 10.1136/thorax.57.8.729] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Current data relating to ventilation in ARDS are reviewed. Recent studies suggest that reduced mortality may be achieved by using a strategy which aims at preventing overdistension of lungs.
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Affiliation(s)
- J J Cordingley
- Department of Anaesthesia and Intensive Care, Royal Brompton Hospital, London SW3 6NP, UK
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Schuster DP, Lange NR, Tutuncu A, Wedel M. Clinical correlation with changing radiographic appearance during partial liquid ventilation. Chest 2001; 119:1503-9. [PMID: 11348960 DOI: 10.1378/chest.119.5.1503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVES To evaluate the chest radiographic filling pattern associated with partial liquid ventilation (PLV) with the perfluorochemical perflubron (LiquiVent; Alliance Pharmaceutical Corp; San Diego CA) as a function of dose and timing. DESIGN Post hoc review of chest radiographs by three independent observers with correlation to clinical variables. SETTING Phase II randomized, uncontrolled, prospective, multicenter clinical trial. PATIENTS Sixteen adult patients with diffuse bilateral infiltrates consistent with acute lung injury and a PaO(2)/fraction of inspired oxygen (FIO(2)) ratio < 300 with positive end-expiratory pressure of 13 cm H(2)O and FIO(2) > or = 0.5. INTERVENTIONS All patients were treated with either a 10-mL/kg or 20-mL/kg loading dose of perflubron followed by maintenance dosing at 3-h intervals to protocol-determined levels. RESULTS There was a significant relationship between inhomogeneous radiographic filling during the first 48 h of treatment and the use of the lower loading dose of perflubron. Inhomogeneous radiographic filling (in 5 patients) was associated with a lower high-dose/FIO(2) ratio at 24 h compared with the remaining patients. These differences resolved by 48 h. There were no other statistically significant correlations identified. CONCLUSIONS The radiographic appearance of PLV with perflubron appears to depend on the dose administered. Lower doses can be associated with both inhomogeneous radiographic filling and a transient deterioration in oxygenation during the first 24 to 48 h of treatment.
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Affiliation(s)
- D P Schuster
- Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St. Louis, MO, USA.
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Degraeuwe PL, Vos GD, Geskens GG, Geilen JM, Blanco CE. Effect of perfluorochemical liquid ventilation on cardiac output and blood pressure variability in neonatal piglets with respiratory insufficiency. Pediatr Pulmonol 2000; 30:114-24. [PMID: 10922133 DOI: 10.1002/1099-0496(200008)30:2<114::aid-ppul6>3.0.co;2-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Respiration and mechanical ventilation induce cyclic variation in cardiac output and blood pressure. We examined these phasic hemodynamic influences of mechanical ventilation during gas ventilation and partial and tidal liquid ventilation in 7 anesthetized and paralyzed young piglets (body weight, 3.0-4.9 kg) made respiratory-insufficient by repeated saline lung lavage. Nonlinear regression analysis of cardiovascular parameters vs. time was done to quantify respiratory-induced fluctuations in hemodynamic variables. The amplitude of oscillations was expressed as a percentage of the mean hemodynamic variable during the study period, and was called the relative oscillation amplitude. The relative oscillation amplitude of left ventricular stroke volume, left ventricular output, systemic arterial pressure, and systemic perfusion pressure was significantly larger (at least twofold) during tidal liquid ventilation compared to partial liquid ventilation. No such differences were observed between gas and partial liquid ventilation at comparable gas ventilator settings. We conclude that in this animal model, within-breath modulation of left ventricular output, systemic blood pressure, and perfusion pressure was significantly increased during tidal liquid ventilation as compared to partial liquid ventilation.
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Affiliation(s)
- P L Degraeuwe
- Department of Pediatrics, University Hospital Maastricht, and Research Institute for Growth and Development, Maastricht University, Maastricht, The Netherlands.
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Abstract
Blood transfusion is a remarkably safe, routine clinical procedure. However, the need for sophisticated blood processing, storage and cross-matching, coupled with increasing concerns about the safety of blood products, has fuelled the search for safe and efficacious substitutes. Candidate materials based on modified haemoglobin (including recombinant molecules) or highly inert, respiratory gas-dissolving perfluorinated liquids (perfluorochemicals) have been developed. The latter are immiscible in aqueous systems and must, therefore, be injected as emulsions. Second-generation perfluorochemical emulsions are available and in clinical trials as temporary intravascular oxygen carriers during surgery, thereby reducing patient exposure to donor blood. One commercial product is currently under Phase III clinical evaluation, with regulatory approval expected within 1 2 years. Other biomedical applications for perfluorochemicals and their emulsions include their use as pump-priming fluids for cardiopulmonary bypass, lung ventilation fluids, anti-cancer agents, organ perfusates and cell culture media supplements, diagnostic imaging agents and ophthalmologic tools. Novel applications for perfluorochemicals as immunomodulating agents are also being explored.
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Affiliation(s)
- K C Lowe
- School of Biological Sciences, University of Nottingham, University Park, UK
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