Effect Of Partial Liquid Ventilation Research Articles

The effect of partial liquid ventilation on inflammatory response in piglets with acute lung injury induced by lipopolysaccharide

To evaluate the effect of partial liquid ventilation (PLV) on pro-inflammatory and anti-inflammatory factors change in lipopolysaccharide (LPS)-induced piglets acute lung injury (ALI). Twelve Shanghai white piglets were randomly divided into mechanical ventilation (MV) group (n=6) and PLV group (n=6). 60 μg×kg(-1)×h(-1) LPS were intravenous infused continuously for 2 hours to induce ALI model. PLV model was set on the basis of the MV by endotracheal injection of perfluorodecalin (PFC, 10 mL/kg). The hemodynamic and respiratory parameters such as mechanics and arterial blood gas analysis were monitored at basic condition and after lung injury establishment (0, 1, 2, 4 hours). The serum levels of interleukin (IL-1β, IL-6, IL-8, IL-10) and tumor necrosis factor-α (TNF-α) were dynamically monitored by enzyme linked immunosorbent assay (ELISA). A lung injury score was used to quantify lung tissues change under light microscopic observations. Ventilation and oxygenation function were improved gradually after PFC endotracheal injection in PLV group, and there were significant difference compared with MV group at 4 hours [heart rate (HR): 144 ± 6 beats/min vs. 179 ± 9 beats/min, respiratory rate (RR): 58 ± 4 beats/min vs. 77 ± 6 beats/min, mean arterial blood pressure (MAP): 99 ± 7 mmHg vs. 75 ± 29 mmHg, dynamic lung compliance (Cdyn): 1.9 ± 0.3 mL×cmH(2)O(-1)×kg(-1) vs. 1.2 ± 0.4 mL×cmH(2)O(-1)×kg(-1), tidal volume (VT): 7.8 ± 0.4 mL/kg vs. 5.8 ± 0.9 mL/kg, mean airway resistance (Raw): 20.5 ± 6.6 cmH(2)O×L(-1)×s(-1) vs. 35.2 ± 4.0 cmH(2)O×L(-1)×s(-1), mean airway pressure (Paw): 1.0 ± 0.5 cmH(2)O vs. 3.0 ± 0.9 cmH(2)O, ventilation efficacy index (VEI): 0.18 ± 0.02 vs. 0.08 ± 0.02, pH value: 7.386 ± 0.143 vs. 7.148 ± 0.165, arterial partial pressure of oxygen (PaO(2)): 121.8 ± 12.5 mmHg vs. 73.6 ± 10.9 mmHg, arterial partial pressure of carbon dioxide (PaCO(2)): 39.6 ± 20.3 mmHg vs. 66.8 ± 23.5 mmHg, oxygenation index (PaO(2)/FiO(2)): 311 ± 35 mmHg vs. 184 ± 27 mmHg, P<0.05 or P<0.01]. All serum cytokines in both groups were significantly increased after LPS-induced ALI, and showed an elevated tendency. The serum pro-inflammatory factors of TNF-α, IL-1β, IL-6 and IL-8 in PLV group were significantly lower than those in MV group at 4 hours (TNF-α: 98.4 ± 21.1 ng/L vs. 178.0 ± 55.0 ng/L, IL-1β: 142.0 ± 38.0 ng/L vs. 226.0 ± 55.0 ng/L, IL-6: 763.0 ± 282.0 ng/L vs. 1 303.0 ± 260.0 ng/L, IL-8: 1 183.0 ± 403.0 ng/L vs. 1 876.0 ± 232.0 ng/L, P<0.05 or P<0.01). There was no significant difference in serum anti-inflammatory factor of IL-10 between PLV and MV groups at 4 hours (292.0 ± 40.0 ng/L vs. 208.0 ± 82.0 ng/L, P>0.05). The ratio of TNF-α/IL-10 in PLV group was significantly decreased compared with MV group at 2 hours (0.58 ± 0.13 vs. 1.13 ± 0.54, P<0.05). The ratio of IL-6/IL-10 in PLV group was significantly decreased compared with MV group at 4 hours (2.72 ± 1.27 vs. 7.17 ± 3.08, P<0.01). Microscopic changes in intra-alveolar and interstitial inflammation, hemorrhage and edema were better in PLV group than those in MV group. The lung injury score of PLV group was lower than MV group (independent lung regions: 9.8 ± 0.8 vs. 11.8 ± 1.0, t=3.956, P=0.003; dependent lung regions: 5.0 ± 0.6 vs. 14.7 ± 2.3, t=10.127, P=0.000). PLV can significantly reduce the levels of pro-inflammatory factors and the ratio of pro-inflammatory/anti-inflammatory factor, which may contribute to the protective effects of PLV on ALI.

Effect of partial liquid ventilation on lung function in oleic acidinduced lung injury model of piglets

Background Pediatric patients are susceptible to lung injury that does not respond to traditional therapies. Partial liquid ventilation (PLV) has been developed as an alternative ventilatory strategy for treating severe lung injury. The aim of this study is to investigate the effect of PLV on lung function in immature piglets. Methods Acute lung injury was induced in 12 Chinese immature piglets by oleic acid (OA). The animals were randomly assigned to two groups (n=6 each group): (1) conventional mechanical ventilation (MV) group and (2) PLV with FC-77 (10 ml/kg) group. Mean arterial blood pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), left atrial pressure (LAP), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), cardiac output (CO), mean pressure of airway (Paw), dynamic lung compliance (Cydn), and arterial blood gases were measured during the observation period. Results No piglet died in either group with severe lung injury. After four hours of ventilation, pH in the MV group gradually decreased to lower than 7.20, while in the PLV group, pH also gradually decreased but remained higher than 7.20 (P &lt;0.05). Partial pressure of oxygen in artery (PaO2) decreased in both groups, but with a significant difference between the PLV group and MV group (P &lt;0.05). Partial pressure of carbon dioxide in artery (PaCO2) increased in both groups, but with a significant difference between the PLV group and MV group (P &lt;0.05). Paw increased in both groups, but was not significantly different (P &gt;0.05). Cydn decreased in both groups, but without a significant difference (P &gt;0.05). At four hours, heart rate (HR) and MAP in both groups decreased. MPAP in both groups increased, and there was a significant difference between the two groups (P &lt;0.05). CVP was stable in both groups. At four hours, PVR and LAP were increased in both groups. CO was decreased in both groups (P &lt;0.05). SVR was stable during the observation time. Conclusion PLV did not improve outcome in changes of lung function.

Protective effect of partial liquid ventilation on non-heart-beating-donor lung

Objective To investigate the protection of non-heart-beating-donor lung with part liquid ventilation.Methods Thirty-six health SD rats were randomly divided into three groups,n =12:oxygen group (group C),salt water group (group B),and part liquid ventilation group (group A).Mechanical ventilation was done for 2 h after establishment of non-heart-beating donor lung model,and airway pressure was measured continuously during 2 h.After 2 h,P-V curve was measured.Resection the under leaves of the rats,observe the different pathological characteristics by electron microscopy of the lung.Right lung was taking irrigation,measurement of bronchial lung lavaged suffactant protein B,C (SP-B,the SP-C) concentrations.Cut the upper lobe toward the right lung and measurement SP-B and SP-C with real-time quantitative polymerase chain reaction (Real-time PCR) testing.Results The dynamic compliance and static compliance of group A are better than group B and C during 2 hours hot ischemia(P ＜0.05) ;Pathology organization score of group A is better than group B and C (P ＜ 0.05) ; SP-B and SP-C enzyme linked immunosorbent assay (ELISA) test and lung tissue of the Real-time PCR testing instructions protein and RNA content are difference,group A is higher than group B and C (P ＜ 0.05).Conclusion Part liquid ventilation protect pulmonary lung function and lung tissue well during heat during ischemia,and have very good protection effect to the SP-B and SP-C. Key words: Perfluorocarbon; Liquid ventilation; Non-heart-beating donor; Protection during warm ischemia

Partial liquid ventilation confers protection against acute lung injury induced by endotoxin in juvenile piglets

To investigate the effect of partial liquid ventilation (PLV) at low inflation pressures on acute lung injury (ALI), endotoxin was administered to healthy anesthetized juvenile piglets. The animals were randomly assigned to two groups, n=6 each: (1) conventional mechanical ventilation (MV) and (2) PLV with perfluorodecalin (10 mL kg(-1)). Compared with MV, PLV improved each cardiopulmonary variable measured. These variables included pulse contour cardiac output, heart rate, blood pH, breathing rate, both partial pressure of arterial oxygen (PaO2) and PaO2/FIO2 (fraction of inspired oxygen), partial pressure of arterial carbon dioxide (PaCO2), dynamic lung compliance, tidal volume, and ventilation efficacy index. Lung morphology also showed less damage in the PLV group, even in non-dependent regions (P<0.05). Our data support the hypothesis that PLV can decrease pulmonary damage, improve gas exchange and cardiac output, and may lead to a better prognosis in endotoxin-induced ALI.

Effect of partial liquid ventilation on cardiac and pulmonary function of acute lung injury in piglets

目的 研究部分液体通气对急性肺损伤幼猪心肺功能的影响.方法 12只上海小白猪,随机分为对照组(n=6)和治疗组(n=6).内毒素60 μg/kg静脉维持诱导肺损伤.治疗组成模后予高氟化碳(C10F18)10 ml/kg灌入气管.于基础状态,成模时,成模后1、2、4 h分别行血气分析、记录心率、血压、呼吸、肺动态顺应性、气道阻力、脉搏轮廓心输出量、全身血管阻力.结果 两组动物成模时氧合指数、肺动态顺应性、脉搏轮廓心输出量均明显下降,各参数组间比较无统计学差异.2 h后对照组氧合指数193.8±47.5,肺动态顺应性(0.8±1.7) ml/(cm H2O·kg),4 h后心输出量(2.1±0.7) L/min;治疗组2 h后氧合指数为261.5±25.8,肺动态顺应性(1.2±0.7) ml/(cm H2O·kg),4 h后心输出量(3.1±0.2) L/min,较对照组均有改善,差异有显著性(P＜0.05).结论 部分液体通气可明显改善肺损伤动物心肺功能。

Why Partial Liquid Ventilation Did Not Fulfill Its Promise

With regard to the recent article byKacmarek and colleagues, we are in complete agreement on the absolute necessity of making public the results of negative trials (1). Discovering the reason(s) why randomized controlled trials did not confirm the information on which they were based can be highly instructive. Partial liquid ventilation (PLV), once introduced in the clinical arena, failed to live up to expectations. These disappointing results of a highly promising technique occurred in the context of major improvements in the outcome of control patients treated with conventional mechanical ventilation (CMV) utilizing a lung-protective strategy. Others have speculated that high-dose perfluorocarbon administration in the LiquiVent trial may have resulted in the socalled baby lung effect (2). We believe that the initial enthusiasm about PLV was based on a too hasty extrapolation from total liquid ventilation (TLV) data and on a poorly adapted study design used to investigate the effectiveness of PLV. In 1991, the scientific community welcomed PLV as a major technical simplification of TLV, and it was assumed that the new hybrid method would preserve all the obvious benefits of TLV. Gradually, however, we learned that the physiology of PLV is fairly complicated and definitely different from that of TLV. The lung-protective effect of PLV turned out to be less important than that associated with TLV. It took several years before the effect of perfluorocarbon liquid volume and the gas ventilation strategy to be used during PLV were investigated in depth. Strange to say, initially, most investigators used a study design adopted from surfactant research to assess PLV efficacy. In animals with respiratory failure, no attempt was made to adjust or optimize the ventilation settings. In a Medline (1966–December 2001) and personal file search, we identified 50 animal studies likely overestimating the benefits of PLV because the control groups were ventilated inadequately in terms of modern standards (3). As a consequence of inappropriate study design, much effort, time, and money have been wasted. When PLV was compared with other recruitment strategies, perfluorocarbons did not prove to be the golden bullet (4, 5), even after optimizing the gas ventilation strategy (6). We hope that PLV researchwill not be perceived as a frustrating misadventure to be forgotten as soon as possible, but rather as an instructive experience not bearing repetition.

The Efficacy of Partial Liquid Ventilation in Lung Protection During Hypotension and Cardiac Arrest: Preliminary Study of Lung Transplantation Using Non–heart–beating Donors

Because of the shortage of suitable brain-dead donors, the use of non-heart-beating donor lungs has been investigated experimentally. However, no effective lung protection method has been developed. In this study, we preliminarily investigated the protective effect of partial liquid ventilation (PLV) on a non-heart-beating rabbit lung. We used 20 male rabbits (mean weight, 3.7 kg) and divided them into 3 groups: the conventional ventilation (control) group, the PLV without cooling group, and the PLV with cooling group. After initially measuring donor cardiopulmonary function, we maintained hypotension at <50 mm Hg for 1 hour followed by 2-hour cardiac arrest. During this time, we used either conventional ventilation or PLV with or without cooling (4 degrees C) for ventilation, and we evaluated the changes in arterial blood gas analysis, pulmonary resistance and elastance, tissue interleukin-8 (IL-8) concentration, and histologic damage. We found no significant difference in arterial oxygen concentration or in carbon dioxide tension among the 3 groups in the hypotensive phase. Pulmonary elastance increased after perfusion of preservation solution in the control group. However, we found no change in elastance in the PLV groups, which was less than that in the control group. Histologic evaluation after perfusion of preservation solution revealed that alveolar structure was damaged significantly less and cell infiltration was milder in the PLV groups than in the control group. Although IL-8 concentrations in the controls increased after cardiac arrest, IL-8 in the PLV groups remained at baseline concentrations during the study period. In this experimental model of hypotension and cardiac arrest, PLV suppresses lung injury when compared with gas-controlled ventilation.

Effect of partial liquid ventilation and nebulized perfluorocarbon on CT lung density distribution: randomized controlled study of experimental lung injury

Perfluorocarbon (PFC) liquid can improve gas exchange in acute lung injury. How PFC aerosol is distributed in the lung is unknown. We induced lung injury in rabbits with saline lavage, followed by mechanical ventilation in the supine position. The animals were divided into three groups: a control group, a group treated with partial liquid ventilation and a group given nebulized perfluorocarbon (PF 5080). We made CT image slices of the excised lungs. In the apical, middle and caudal slices we defined three regions of interest, from anterior to posterior, and noted the mean attenuation of each area. We also studied two rabbits which had not received lung injury or mechanical ventilation. Group means were different between the normal rabbits and all three study groups. There was a difference between the control and partial liquid ventilation groups, and between the partial liquid ventilation and nebulized groups, but no difference between the nebulized and control groups. Within each treatment group, there was no regional difference in the distribution of density. PF 5080 is not deposited in large amounts by aerosol. Less PFC was found in the lungs after partial liquid ventilation than expected. Within treatment groups, lung densities indicate less gravitational and regional differences than found in other studies.

The Efficacy of Partial Liquid Ventilation on Lung Protection during Hypotension and Cardiac Arrest: Preliminary study for Lung Transplantation from Non-Heart Beating Donors

ackground: Because of the shortage of suitable brain-dead donors, the use of non–heart-beating donor lungs has been investigated experimentally. However, no effective lung protection method has been developed. In this study, we preliminarily investigated the protective effect of partial liquid ventilation (PLV) on a non–heart-beating rabbit lung. ethods: We used 20 male rabbits (mean weight, 3.7 kg) and divided them into 3 groups: the conventional ventilation (control) group, the PLV without cooling group, and the PLV with cooling group. After initially measuring donor cardiopulmonary function, we maintained hypotension at 50 mm Hg for 1 hour followed by 2-hour cardiac arrest. During this time, we used either conventional ventilation or PLV with or without cooling (4°C) for ventilation, and we evaluated the changes in arterial blood gas analysis, pulmonary resistance and elastance, tissue interleukin-8 (IL-8) concentration, and histologic damage. esults: We found no significant difference in arterial oxygen concentration or in carbon dioxide tension among the 3 groups in the hypotensive phase. Pulmonary elastance increased after perfusion of preservation solution in the control group. However, we found no change in elastance in the PLV groups, which was less than that in the control group. Histologic evaluation after perfusion of preservation solution revealed that alveolar structure was damaged significantly less and cell infiltration was milder in the PLV groups than in the control group. Although IL-8 concentrations in the controls increased after cardiac arrest, IL-8 in the PLV groups remained at baseline concentrations during the study period. onclusion: In this experimental model of hypotension and cardiac arrest, PLV suppresses lung injury when compared with gas-controlled ventilation. J Heart Lung Transplant 2005;24:723–9. Copyright © 2005 by the International Society for Heart and Lung Transplantation.

Partial liquid ventilation does not affect BALF TNF-, MIP-2, CINC-1 concentrations, or CD11b cell surface expression, but does increase macrophage proportion among BALF cells in the acute phase of rat LPS-induced lung injury.

To elucidate the mechanism of anti-inflammatory effect of partial liquid ventilation (PLV), cytokine concentration, surface CD11b, and macrophage expression were investigated in BALF. The 30-minutes group was treated with gas ventilation (GV) for 30 minutes after intratracheal LPS administration. The GV group was prepared in the same manner as the 30-minutes group, then the GV was continued for the following 2 hours. The PLV group was treated in the same manner as the 30-minutes group, and then received PLV with perflubron for the following 2 hours. Animals were euthanized to receive BAL. The PLV group showed a tendency to have a higher concentration than the GV group of TNF-alpha, MIP-2, and CINC-1 as measured by ELISA, although there were no significant differences. The ratio of expressions of CD11b and macrophages to total leukocytes were determined by flow-cytometry. There were no significant differences in the ratio of CD11b-positive expression to acquired cells (GV: 63.6 +/- 8.4%, PLV: 60.5+/-5.4%, P=0.73). However, the proportion of macrophages was significantly increased (GV: 5.6 +/-1.5, PLV: 14.0+/-1.3, P=0.006). These results suggest that the anti-inflammatory effect of PLV is not caused by the change in CD11b expression, and that PLV affects the proportion of macrophage among BALF cells.

Effect of partial liquid ventilation on bacterial clearance during Pseudomonas aeruginosa-induced lung injury in rats.

Partial liquid ventilation (PLV) has been shown to exhibit anti-inflammatory properties during non-infectious models of acute lung injury. The aim of this experimental study was to assess the effects of PLV on bacterial clearance during Pseudomonas aeruginosa-induced pneumonia in rats. The rats were assigned to four groups 4 h after bacterial challenge according to the kind of mechanical ventilation [gas ventilation (GV) or PLV, 6 ml/kg perflubron plus 2 ml/kg per h] and to the level of PEEP used (3 or 8 cm of water). Physiologic measures were recorded during anesthesia (arterial blood gases, airway and blood pressures) for 4 subsequent hours until sacrifice. No improvement of oxygenation was demonstrated in any group. The bacterial counts were higher in PLV-PEEP 8 rats compared to GV-PEEP 8 rats: median, 1.7.10(4) cfu (25th-75th percentiles, 1.2.10(4)-1.8.10(4)) versus 1.1.10(4) (8.7.10(3)-1.3.10(4))/ml of BAL fluid and 4.0.10(6) cfu (2.0.10(6)-5.5.10(6)) versus 1.7.10(6) cfu (9.7.10(5)-3.2.10(6))/ml of lung homogenate, respectively ( P<0.05, n=8/10 surviving rats per group). PEEP 8 was associated with a significant decrease in neutrophil recruitment in BAL fluid compared to PEEP 3 in both GV and PLV groups. Additional in vitro experiments demonstrated that perflubron induced a decrease in phagocytosis of P. aeruginosa by alveolar neutrophils. These results demonstrate that PLV is associated with an impaired bacterial clearance during early pneumonia in rats, which could have been favored by decreased bacterial phagocytosis by neutrophils.

Segmental hemodynamics during partial liquid ventilation in isolated rat lungs

Partial liquid ventilation (PLV) is a means of ventilatory support in which gas ventilation is carried out in a lung partially filled with a perfluorocarbon liquid capable of supporting gas exchange. Recently, this technique has been proposed as an adjunctive therapy for cardiac arrest, during which PLV with cold perfluorocarbons might rapidly cool the intrathoracic contents and promote cerebral protective hypothermia while not interfering with gas exchange. A concern during such therapy will be the effect of PLV on pulmonary hemodynamics during very low blood flow conditions. In the current study, segmental (i.e. precapillary, capillary, and postcapillary) hemodynamics were studied in the rat lung using a standard isolated lung perfusion system at a flow rate of 6 ml/min (∼5% normal cardiac output). Lungs received either gas ventilation or 5 or 10 ml/kg PLV. Segmental pressures and vascular resistances were determined, as was transcapillary fluid flux. The relationship between individual hemodynamic parameters and PLV dose was examined using linear regression, with n=5 in each study group. PLV at both the 5 and 10 ml/kg dose produced no detectable changes in pulmonary blood flow or in transcapillary fluid flux (all R 2 values<0.20). Conclusion: In an isolated perfused lung model of low flow conditions, normal segmental hemodynamic behavior was preserved during liquid ventilation. These data support further investigation of this technique as an adjunct to cardiopulmonary resuscitation.

Effects of Partial Liquid Ventilation on Unilateral Lung Injury in Dogs

The overall physiologic effect of partial liquid ventilation (PLV) in the setting of unilateral lung injury remains unclear. Therefore, we evaluated the effect of PLV on gas exchange in unilateral lung injury. Left unilateral lung injury was induced in 14 adult dogs by oleic acid instillation into a left pulmonary artery. The animals were divided into two groups: gas ventilation (GV) and PLV. During both GV and PLV, systemic blood gas levels were analyzed. Oxygen consumption (O(2)), carbon dioxide production (CO(2)) and pulmonary blood flow (Q) of both the right lung (uninjured lung) and left lung (injured lung) were measured. During PLV, O(2) of the injured left lung (o(2)-injured), CO(2) of the injured left lung (CO(2)-injured), and Q of the injured left lung (Q-injured) were greater than those in GV (O(2)-injured, 41.6 mL/min vs 23.4 mL/min, p = 0.006; CO(2)-injured, 34.4 mL/min vs 25.5 mL/min, p = 0.026; and Q-injured, 0.47 L/min vs 0.22 L/min, p = 0.002, respectively). However, overall PaO(2) during PLV was less than that during GV, likely due to either a redistribution of Q toward the injured lung (PLV Q-injured, 0.47 L/min vs GV Q-injured, 0.22 L/min; p = 0.002) or reduced gas exchange efficiency in the healthy lung. We conclude that in our model, PLV increases O(2) and VCO(2) in the injured lung. However, over all gas exchange efficiency is reduced.

Effect of partial liquid ventilation on pulmonary vascular permeability and edema after experimental acute lung injury.

We evaluated the effects of partial liquid ventilation (PLV) with two different dosages of the perfluorocarbon LiquiVent (perflubron) on pulmonary vascular permeability and edema formation after oleic acid (OA)-induced acute lung injury in dogs. We used imaging with positron emission tomography to measure fractional pulmonary blood flow, lung water concentration (LWC), and the pulmonary transcapillary escape rate (PTCER) of (68)Ga-labeled transferrin at 5 and 21 h after lung injury in five dogs undergoing conventional mechanical ventilation (CMV), five dogs undergoing low-dose PLV (perflubron at 10 ml/kg), and four dogs undergoing high dose PLV (perflubron at 30 ml/kg). A positive end-expiratory pressure of 7.5 cm H(2)O was used in all dogs. After OA (0.08 ml/kg)- induced lung injury, there were no significant differences or trends for PTCER or LWC at any time when the PLV groups were compared with the CMV group. However, lung tissue myeloperoxidase activity was significantly lower in the combined PLV group than in the CMV group (p = 0.016). We conclude that after OA-induced lung injury, the addition of PLV to CMV does not directly attenuate pulmonary vascular leak or lung water accumulation. Rather, the benefits of such treatment may be due to modifications of the inflammatory response.

Partial liquid ventilation influences pulmonary histopathology in an animal model of acute lung injury

Purpose: The aim of this study was to assess the effect of partial liquid ventilation (PLV) and conventional mechanical ventilation (CMV) in the pattern of distribution of lung injury in a rabbit model of acute lung injury. Materials and Methods: Animals (1.5 to 3.5 kg) were assigned to receive CMV (tidal volume of 10 mL/kg and a PEEP of 5 cm H 2O) or PLV with 18 mL/kg of intratracheal perflubron (tidal volume of 10 mL/kg and a PEEP of 5 cm H 2O). Lung injury was elicited by intravenous administration of Escherichia coli endotoxin. Uninjured animals ventilated as the CMV group served as controls. After 4 hours of mechanical ventilation, the lungs were removed and tissue injury was assessed by light microscopy using a scoring system. Results: Animals in the CMV group had higher lung injury scores in comparison to the PLV group (10 ± 4.5 vs. 5 ± 3.3, respectively, P < .05). The injury scores were similar for nondependent lung regions (CMV: 8 ± 4.3, PLV: 6 ± 2.9) but significantly different for the dependent regions (CMV:12 ± 4.6, PLV: 5 ± 3.8, P<.05). Conclusions: PLV is associated with significant attenuation of lung injury, in comparison to CMV. This effect is predominantly due to attenuation of injury in the dependent region of the lung.

Partial liquid ventilation with perfluorocarbon improves gas exchange and decreases inflammatory response in oleic acid-induced lung injury in beagles.

The aim of this study was to determine the effect of partial liquid ventilation (PLV) using a perfluorocarbon (PFC) on gas exchange and lung inflammatory response in a canine acute lung injury model. After inducing severe lung injury by oleic acid infusion, beagle dogs were randomized to receive either gas ventilation only (control group, n = 6) or PLV (PLV group, n = 7) by sequential instillation of 10 mL/kg of perfluorodecalin (PFC) at 30 min intervals till functional residual capacity was attained. Measurements were made every 30 min till 210 min. Then the lungs were removed and bronchoalveolar lavage (BAL) (35 mL/kg) was performed on the right lung and the left lung was submitted for histologic analysis. There was significant improvement in PaO2 and PaCO2 in the PLV group compared to the control group (p < 0.05) which was associated with a significant decrease in shunt (p < 0.05). There was no significant difference in parameters of lung mechanics and hemodynamics. There was a significant decrease in cell count and neutrophil percentage in BAL fluid and significantly less inflammation and exudate scores in histology in the PLV group (p < 0.05). We conclude that PLV with perfluorodecalin improves gas exchange and decreases inflammatory response in the acutely-injured lung.

Experimental study of partial liquid ventilation in the setting of acute respiratory failure induced by sea water lung lavage in rabbits.

To study the effect of partial liquid ventilation (PLV) with perfluorocarbon on acute respiratory failure, 3 groups of 17 rabbits were examined to compare. After acute respiratory failure was induced by lung lavage with sea water in 12 of the 17 rabbits, 7 of the 12 rabbits were treated with conventional mechanical ventilation (AC group) and 5 of the 12 rabbits were treated with PLV using perfluorocarbon (AP group). The remaining 5 normal rabbits without acute respiratory failure were treated with PLV with perfluorocarbon as a control group (PL group). In the PL group, PaO2, PaCO2, blood pH, pulmonary compliance or pathological findings were not so changed after PLV. In the AC and AP groups, PaCO2 significantly increased, and in contrast, PaO2 and pulmonary compliance significantly decreased after lung lavage. However, these findings improved to almost the same levels as those of a control group within 2 h after the PLV treatment in the AP group, but in the AC group, these gradually deteriorated over time. As for the pathological findings, pulmonary vascular congestion, alveolar hemorrhage and inflammatory infiltration were observed in the AC group. However, these findings were not observed in the specimens of the AP group. From these results, PLV with perfluorocarbon was shown to be useful to improve gas exchange and pulmonary functions without major side effects.

Cardiopulmonary interaction during partial liquid ventilation in surfactant-treated preterm lambs.

Gas ventilation following instillation of perfluorochemical (PFC) liquid, partial liquid ventilation (PLV), improves gas exchange and pulmonary mechanics in neonatal animals and humans with severe respiratory distress. The effect of PLV on cardiac contractility, performance, pulmonary blood flow and ductal shunt has not been fully described. To this end, we evaluated these indices of cardiopulmonary function in eight conventionally gas ventilated, surfactant-treated premature lambs (125 days gestation) before and during PLV. Animals were instrumented with central venous and aortic lines. Serial evaluation of arterial blood chemistry/pressure, and pulmonary mechanics was performed; cardiac contractility, performance, pulmonary blood flow and ductal shunts were serially assessed by echocardiography. As compared to conventional gas ventilation, during PLV there was a significant decrease in left ventricular meridian (22.5+/-6.6 SE vs 8.1+/-1.4 SE g/cm2, P < 0.02) and circumferential wall stress (54.1+/-16.5 vs 24.4+/-3.8 SE g/cm2, P < 0.04) at end systole. The fall in wall stress at end systole was associated with a significant decrease in left ventricular internal diameter (1.2+/-0.05 SE vs 1.04+/-0.045 SE cm; P < 0.01). There were no significant changes in heart rate, systemic arterial and central venous pressures, systemic vascular resistance, left ventricular shortening and ejection fractions during PLV. The decrease in wall stress was associated with a significant decrease in mean airway pressures (15.9+/-1.1 SE vs 9.9+/-0.2 SE cmH2O; P < 0.05) and ostensibly a change in intrathoracic pressures during PLV. There were no significant differences in blood flows (pre vs during PLV; ml/min/kg): pulmonary (226+/-62 SE vs 293+/-65 SE), aortic (237+/-36 SE vs 204+/-21 SE), and left to right ductal (119+/-25 SE vs 105.5+/-26 SE) measured before and during PLV. Cardiac output and pulmonary blood flow do not change significantly during PLV and therefore do not appear to contribute to improved gas exchange. This stable cardiac performance occurs at lower wall stress and thereby more advantageous energetic conditions.

Partial liquid ventilation enhances surfactant phospholipid production.

To study the effect of partial liquid ventilation on phospholipid metabolism. Prospective, controlled laboratory study. University-affiliated animal research facility. Mature New Zealand white rabbits (n = 17). The rabbits were sedated, anesthetized, and instrumented with tracheostomy and the insertion of an arterial catheter. The rabbits were sequentially assigned to receive conventional mechanical ventilation or partial liquid ventilation with Perflubron (18 mL/kg by bolus fill). Ventilator strategies were identical in both groups and consisted of an FiO2 of 0.5, positive end-expiratory pressure of 4 cm H2O, effective tidal volume of 8 to 13 mL/kg, and rate to maintain Pco2 of 30 to 40 torr (4.0 to 5.3 kPa). Phosphatidylcholine was labeled in vivo by injection of 3H-methylcholine (25 microCi/kg iv). Ventilation was continued for 5.5 hrs. When animals were killed, phosphatidylcholine was extracted from the total lung lavage and from the pulmonary parenchyma. After the separation of phospholipids by thin-layer chromatography, the 3H activity was determined by liquid scintillation counting. Inorganic phosphorus was also determined to assess the enrichment of the phosphatidylcholine. The 3H-phosphatidylcholine activity in the partial liquid ventilation treated- vs. control rabbits demonstrated a 53% increase (p = .051) in the lavage and a 48% increase (p = .013) in the parenchyma for a net 50% (p = .012) total pulmonary increase. The phospholipid content of the partial liquid ventilation treated- vs. the control rabbits demonstrated a 78% increase (p = .046). We conclude that partial liquid ventilation with Perflubron appears to have no negative impact on phospholipid metabolism but rather enhances surfactant phospholipid synthesis and secretion.

Hemodynamic effects of partial liquid ventilation with perfluorocarbon in acute lung injury.

To assess the effect of partial liquid ventilation with perfluorocarbons on hemodynamics and gas exchange in large pigs with induced acute lung injury (ALI). Randomized, prospective, double-control, experimental study. Experimental intensive care unit of a university. Eighteen large pigs (50 +/- 5 kg body weight) with an average anterior posterior thoracic diameter of 24 cm and induced acute lung injury. All animals were surfactant depleted by lung lavage to a PaO2 below 100 mmHg and randomized to receive either perflubron (n = 6) or saline (n = 6) in five intratracheal doses of 5 ml/kg at 20-min intervals, or no instillation (n = 6). In all animals heart rate, arterial pressures, pulmonary pressures, cardiac output and blood gases were recorded at 20-min intervals. There was no deleterious effect on any hemodynamic parameter in the perflubron group, whereas systolic and mean pulmonary arterial pressure values showed a persistent decrease after the first 5 ml/kg of perflubron, from 48.7 +/- 14.1 to 40.8 +/- 11.7 mmHg and from 39.7 +/- 13.2 to 35.2 +/- 12.0 mmHg, respectively. Perflubron resulted in a significant (ANOVA P < 0.01), dose-dependent increase in PaO2 values from 86.3 +/- 22.4 to a maximum of 342.4 +/- 59.4 mmHg at a dose of 25 ml/kg; the other groups showed no significant increase in PaO2. Tracheal instillation of perflubron in induced ALI results in a dose-dependent increase in PaO2 and has no deleterious effect on hemodynamic parameters.