BACKGROUNDPediatric 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.

METHODSAcute 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.

RESULTSNo 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 < 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 < 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 < 0.05). Paw increased in both groups, but was not significantly different (P > 0.05). Cydn decreased in both groups, but without a significant difference (P > 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 < 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 < 0.05). SVR was stable during the observation time.

CONCLUSIONPLV did not improve outcome in changes of lung function.

Animals ; Liquid Ventilation ; Lung Injury ; chemically induced ; therapy ; Oleic Acid ; Swine

BACKGROUNDPediatric patients are susceptible to lung injury that does not respond to traditional therapies. Total liquid ventilation has been developed as an alternative ventilatory strategy for severe lung injury. The aim of this study is to investigate the effect of total liquid ventilation on oleic acid (OA)-induced lung injury in piglets.

METHODSTwelve Chinese immature piglets were induced acute lung injury by OA. Twelve piglets were randomly treated with conventional gas ventilation (control group) or total liquid ventilation (study group) for 240 minutes. Samples for blood gas analysis were collected before, and at 60-minute intervals after OA-induced lung injury. The degree of lung injury was quantified by histologic examination. The inflammatory cells and the levels of IL-1β, IL-6, IL-10 and TNF-α in plasma, tissue and bronchoalveolar lavage were analyzed.

RESULTSNeutrophil and macrophage counts in bronchoalveolar lavage were significantly decreased in the study group (P < 0.05). The total lung injury score was also reduced in the study group (P < 0.05). The concentrations of IL-1β, IL-6, IL-10 and TNF-α in plasma, tissue and bronchoalveolar lavage were significantly reduced in the study group (P < 0.05).

CONCLUSIONSTotal liquid ventilation reduces biochemical and histologic OA-induced lung injury in piglets.

Acute Lung Injury ; chemically induced ; metabolism ; therapy ; Animals ; Interleukin-10 ; metabolism ; Interleukin-1beta ; metabolism ; Interleukin-6 ; metabolism ; Liquid Ventilation ; methods ; Oleic Acid ; toxicity ; Swine ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUNDPediatric patients are susceptible to lung injury. Acute lung injury in children often results in high mortality. Partial liquid ventilation (PLV) has been shown to markedly improve oxygenation and reduce histologic evidence of injury in a number of lung injury models. This study was designed to examine the hypothesis that PLV would attenuate the production of local and systemic tumor necrosis factor (TNF)-α in an immature piglet model of acute lung injury induced by oleic acid (OA).

METHODSTwelve Chinese immature piglets were induced acute lung injury by OA. The animals were randomly assigned to two groups of six animals, (1) conventional mechanical ventilation (MV) group and (2) PLV with 10 ml/kg FC-77 group.

RESULTSCompared with MV group, the PLV group had better cardiopulmonary variables (P < 0.05). These variables included heart rate, mean blood pressure, blood pH, partial pressure of arterial oxygen (PaO2), PaO2/inspired O2 fraction (FiO2) and partial pressure of arterial carbon dioxide (PaCO2). PLV reduced TNF-α levels both in plasma and tissue compared with MV group (P < 0.05).

CONCLUSIONPLV provides protective effects against TNF-α response in OA-induced acute lung injury in immature piglets.

Acute Lung Injury ; chemically induced ; metabolism ; therapy ; Animals ; Animals, Newborn ; Liquid Ventilation ; methods ; Oleic Acid ; toxicity ; Swine ; Tumor Necrosis Factor-alpha ; blood ; metabolism

BACKGROUNDPediatric patients are susceptible to lung injury. Acute lung injury (ALI) in children often results in a high mortality. Partial liquid ventilation (PLV) has been shown to markedly improve oxygenation and reduce histologic evidence of injury in a number of lung injury models. This study aimed to examine the hypothesis that PLV would attenuate the production of local and systemic cytokines in an immature piglet model of ALI induced by oleic acid (OA).

METHODSTwelve Chinese immature piglets were induced to develop ALI by oleic acid. The animals were randomly assigned to two groups (n = 6): (1) conventional mechanical ventilation (MV) group and (2) PLV with FC-77 (10 ml/kg) group.

RESULTSCompared with MV group, PLV group got better cardiopulmonary variables (P < 0.05). These variables included heart rate, mean blood pressure, blood pH, partial pressure of arterial oxygen (PaO2), PaO2/FiO2 and partial pressure of arterial carbon dioxide (PaCO2). Partial liquid ventilation reduced IL-1beta, IL-6, IL-10 and TNF-alpha both in plasma and tissue concentrations compared with MV group (P < 0.05).

CONCLUSIONSPartial liquid ventilation provides protective effects against inflammatory responses in the lungs of oleic acid-induced immature piglets.

Animals ; Fluorocarbons ; therapeutic use ; Hemodynamics ; drug effects ; Inflammation ; chemically induced ; therapy ; Interleukin-10 ; metabolism ; Interleukin-1beta ; metabolism ; Interleukin-6 ; metabolism ; Liquid Ventilation ; methods ; Lung Injury ; immunology ; therapy ; Oleic Acid ; toxicity ; Random Allocation ; Respiration, Artificial ; Swine ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUND: We examined the effects of varying inspiratory to expiratory (I : E) ratio on gas exchange and hemodynamics during high frequency partial liquid ventilation (HFPLV), a combination of high frequency ventilation (HFV) and partial liquid ventilation (PLV), in a rabbit model of acute lung injury. METHODS: Twelve rabbits treated with repeated saline lavage were divided into two groups. In the HFPL group (n = 6), 6 ml/kg of perfluorodecaline was administered through the endotracheal tube. Rabbits in this group and in the HFJ group (n = 6) were treated with high frequency jet ventilation (HFJV) at I : E ratios of 1 : 1, 1 : 2, and 1 : 3 for 15 minutes, and arterial blood gas, mixed venous blood gas and hemodynamic parameters were measured. RESULTS: We observed no significant respiratory and hemodynamic differences between the two groups. At an I : E ratio of 1 : 1, the PaO2 was significantly higher, and the shunt rate and PaCO2 were significantly lower in both groups, compared with I : E ratios of 1 : 2 and 1 : 3. Cardiac output at the 1 : 3 I : E ratio was significantly higher than at 1 : 1. CONCLUSIONS: These findings indicate that, in this model, a 1 : 1 I : E ratio was superior for oxygenation and ventilation than I : E ratios of 1 : 2 or 1 : 3, while having no detrimental effects on hemodynamics.
Acute Lung Injury ; Cardiac Output ; Hemodynamics ; High-Frequency Jet Ventilation ; High-Frequency Ventilation ; Liquid Ventilation ; Oxygen ; Rabbits ; Therapeutic Irrigation ; Ventilation

OBJECTIVETo observe the pathological change of partial liquid ventilation (PLV) through establishing the rabbit model of acute lung injury (ALI) induced by meconium aspiration.

METHODSAdult, healthy male or female New Zealand white rabbits were randomly allocated into six groups as follows: (1) control group, (2) conventional mechanical ventilation (CMV) group, (3) high-frequency oscillatory ventilation (HFOV) group, (4) CMV combined with PLV group, (5) HFOV combined with PLV group and (6) normal group. The animals were anesthetized with 1% pentobarbital and tracheotomy was performed and endotracheal tube was placed, 20% meconium fluid (3 ml/kg) was quickly injected into the lung through the endotracheal tube and arterial blood gas was analyzed 30 minutes later. ALI was indicated when P/F ratio (PaO2)/FiO(2)) was < or = 300 mm Hg (1 mm Hg = 0.133 kPa) and Cdyn Dynamic Compliance declined by more than 30% of the baseline. The animals were then randomly allocated into one of the 6 groups. In PLV groups (including CMV + PLV and HFOV + PLV) warmed (37 degrees C) and oxygenated perfluorocarbon was slowly instilled into the lungs of the rabbits through the endotracheal tube at a low-dose 3 ml/kg, then set 15-min positive pressure by sacculus proprius to guarantee perfluorocarbon to steadily diffuse in to the lungs. Six hours after ventilation the animals were sacrificed by using overdose of room air instillation via vein. The lungs were taken and fixed in 4% paraformaldehyde (PFA) and were stained with hematoxylin-eosin (HE). Pathological evaluations included inflammatory manifestation, edema and hemorrhage in both alveolar and interstitial area, damages of small airway (alveolar tube and alveolar bursa) and hyaline membrane formation. One way analysis of variance, Student Newman-Keuls (SNK) method and Kruskal-Wallis (K-W) test were used for comparisons.

RESULTSWith the exception of normal group 30 minutes after meconium injections blood gas analysis in different groups showed significant changes and PaO(2)/FiO(2) (< 300 mm Hg), Cdyn declined by more than 60% compared with baseline (P < 0.05). The pathological analysis showed that alveolar and interstitial inflammation, edema, alveolar and interstitial hemorrhage, and small airway damage existed in each group. The hyaline membrane formation was found in one of CMV + PLV group rabbits. The perfluorocarbon-treated animals (CMV + PLV and HFOV + PLV) showed significantly less injury in dependent lung and less damage of small airway (CMV + PLV or HFOV + PLV vs. CMV = 1.1 +/- 0.4 or 0.9 +/- 0.3 vs 2.6 +/- 0.5) compared with the animals of CMV group (P < 0.01). HFOV group (2.1 +/- 0.3) also had less alveolar and interstitial inflammation compared with CMV group (3.0 +/- 0) (P < 0.05), and there was less evidence of alveolar and interstitial edema in the animals treated with HFOV + PLV (1.0 +/- 0.7) compared with CMV (2.0 +/- 0.8) (P < 0.01). Treatment with perfluorocarbon did not result in significant difference in alveolar and interstitial hemorrhage. Compared with CMV and HFOV groups, the groups treated with PLV showed lower mortality of animals (21.4% and 14.3%).

CONCLUSIONSPLV can alleviate the histological damage of acute lung injury induced by meconium aspiration and increased survival chance and therefore PLV would be a useful treatment for MAS. The effectiveness and safety of application of PLV should be evaluated in clinical studies.

Acute Lung Injury ; etiology ; pathology ; Animals ; Animals, Newborn ; Disease Models, Animal ; Female ; Liquid Ventilation ; Male ; Rabbits

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 99.2 +/- 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.
Animals ; Dogs ; Liquid Ventilation/*methods ; Models, Animal ; Prone Position/*physiology ; Pulmonary Gas Exchange/*physiology ; Research Support, Non-U.S. Gov't ; Respiratory Distress Syndrome, Adult/physiopathology/*therapy

BACKGROUND: Morbidity and mortality rates from acute respiratory failure remain noteworthy despite advances in conventional ventilatory techniques and improvements in supportive care. Repeated, the large tidal volume breaths during positive pressure mechanical ventilation lead to destruction of alveoli and pulmonary capillaries. Moreover, the overdistention of terminal lung units is considered as an important mechanism of ventilator induced lung injury. High frequency ventilation (HFV) is a technique involving a small tidal volume, and a higher than physiologic respiratory rate. Partial liquid ventilation (PLV), also known as perfluorocarbon-associated gas exchange, is a new technique for respiratory support. This study was designed to compare conventional mechanical ventilation (CMV) and high frequency jet ventilation (HFJV), in combination with PLV. METHODS: Twenty rabbits were anesthetized with xylazine, ketamine and vecuronium. We studied rabbits with lung injury induced by saline lavage. Animal were randomized into one of two treatment groups. Ventilator parameters included the following; CMV: FIO2 of 1.0, respiratory rate 20-30 breaths/min, I/E ratio 1 : 1; HFJV: respiratory rate 2 Hz, driving pressure 2psi. Animals were briefly disconnected from the ventilator and lungs were lavaged with warmed saline. This procedure was repeated until PaO2 < 100 mmHg. After one hour, we initiated the instillation of perfluorodecalin via an endotracheal tube. Baseline measurements were performed at 60 mins after the induction of anesthesia and repeated again at hour after the induction of lung injury, which included 30 mins of stabilization. After PFD instillation, data were recorded. RESULTS: All animals developed hypoxemia after the lung injury, but oxygenation improved significantly after perfluorodecalin instillation. The PLV-HFJV group showed a high pH and a low PaCO2. Mean arterial pressure, cardiac index and systemic vascular resistance was differed significantly. Although there were no qualitative histological differences between lungs ventilated with HFJV on CMV, the lower lobes of all PLV-treated animals were damaged less than the upper lobes, but without statical significance. CONCLUSIONS: PLV-HFJV produced a more efficient gas exchange than PLV-CMV. No significant difference was observed in the pulmonary pathologies of the groups.
Anesthesia ; Animals ; Anoxia ; Arterial Pressure ; Capillaries ; High-Frequency Jet Ventilation* ; High-Frequency Ventilation ; Hydrogen-Ion Concentration ; Ketamine ; Liquid Ventilation* ; Lung Injury* ; Lung* ; Mortality ; Oxygen ; Pathology ; Rabbits ; Respiration, Artificial ; Respiratory Insufficiency ; Respiratory Rate ; Therapeutic Irrigation ; Tidal Volume ; Vascular Resistance ; Vecuronium Bromide ; Ventilator-Induced Lung Injury ; Ventilators, Mechanical ; Xylazine

BACKGROUND: Perfluorocarbon (PFC) liquids have high oxygen carrying capacity and relatively low surface tension allowing them to spread evenly through the diseased lung, especially in the case of adult respiratory distress syndrome. But few studies have demonstrated the effects of PFC on a bronchoconstriction model. The aim of this study was to investigate the effects of PFC on pulmonary mechanics and gas exchange in methacholine-induced bronchoconstricted cats using a flow interruption technique. METHODS: Twenty male cats were divided into four groups; control group (group C, n = 5), PFC group (group P, PFC 5 ml/kg, n = 5), methacholine group (group M, 25 microgram/kg/min, n = 5), PFC and methacholine group (group MP, n = 5). Respiratory pressure using a flow interruption technique was measured immediately after stabilizing the heart rate and blood pressure 0, and 15, 30 and 60 min after the start of the intratracheal administration of PFC and/or methacholine infusion, depending on the group. Arterial blood gas analysis was done to compare arterial partial oxygen pressure among the groups at the time of measuring the pressure values. The pressure data was transferred to a personal computer and analyzed using ANADAT software program. Respiratory, airway and tissue viscoelastic pressure were calculated. Statistical analysis was done by ANOVA and statistical significance was defined as P <0.05. RESULTS: Group M and MP showed significantly increased airway pressures compared with group C (P <0.05), but there was no difference among the groups in terms of viscoelastic pressure. Arterial blood gas analysis showed that group P and MP had lower arterial partial oxygen pressures than group C (P <0.05). CONCLUSIONS: This study demonstrates that the intratracheal administration of PFC in a bronchoconstriction cat model increases airway pressure more than tissue viscoelastic pressure, and decreased arterial oxygen partial pressure. We conclude that the intratrachel administration of PFC is not to be recommended in bronchoconstrictive situations.
Airway Resistance ; Animals ; Blood Gas Analysis ; Blood Pressure ; Bronchoconstriction* ; Cats* ; Natural Resources ; Heart Rate ; Humans ; Liquid Ventilation ; Lung ; Male ; Mechanics ; Methacholine Chloride ; Microcomputers ; Oxygen ; Partial Pressure ; Pulmonary Gas Exchange* ; Respiratory Distress Syndrome, Adult ; Respiratory Mechanics* ; Surface Tension

Combined Modality Therapy ; High-Frequency Ventilation ; Humans ; Liquid Ventilation ; Nitric Oxide ; therapeutic use ; Pulmonary Surfactants ; therapeutic use ; Respiration, Artificial ; Respiratory Insufficiency ; therapy