Partial Liquid Ventilation Research Articles

Effects of different mechanical ventilation methods on morphology of type II alveolar epithelium cell in newborn piglets with acute lung injury

Objective To investigate the effects of 3 different ventilation methods, including conventional mechanical ventilation(CMV), high-frequency oscillatory ventilation(HFOV) and partial liquid ventilation(PLV), on the morphology of type Ⅱ alveolar epithelium cell(ACEⅡ) of newborn piglet with acute lung injury(ALI). Methods Twenty-four less than 3-day-old newborn piglets were enrolled.After ALI was established with saline lavage(38 ℃, 0.035 L/kg), newborn piglets were randomly assigned to 4 study groups: control group(n=6, no ventilation), CMV group(n=6), HFOV group(n=6), and PLV group(n=6, 38 ℃, 0.018 L/kg). Piglets in the 4 groups were sacrificed after being ventilated for 24 hours, and the number, area, density of fluorescence of ACEⅡ were detected. Results Through 24 hours mechanical ventilation, the numbers of ACEⅡ in CMV group, HFOV group and PLV group remained were 30±5, 52±5, 81±7, respectively, while areas of fluorescence were 340.40±47.50, 329.69±124.50, 295.55±109.30, respectively, and there were significant differences among the 3 groups, and the population mean of density of fluorescence had significant difference among the 3 groups.The number of ACEⅡremains was lowest in CMV group compared with HFOV group(P=0.026) and PLV group(P=0.000), and the density of fluorescence of ACEⅡ was lowest in CMV group compared with HFOV group(P=0.001) and PLV group(P=0.002). Conclusions Different mechanical ventilations have various effects for ACEⅡ, and CMV is the most harmful mechanical ventilation on ACEⅡ, while PLV is the least harmful. Key words: Mechanical ventilation; Type Ⅱ alveolar epithelium cell; Morphology; Newborn piglet

Cerebral blood flow is not affected during perfluorocarbon dosing with volume-controlled ventilation

Perfluorocarbon administration increases cerebral blood flow. This can be mitigated by preventing a rise in carbon dioxide by adjusting pressure-controlled ventilation. Volume-controlled ventilation should prevent increases in arterial carbon dioxide and cerebral blood flow. This study aims to determine if cerebral blood flow is increased during administration of 10 mL/kg of perfluorocarbon while using volume-controlled ventilation. Two New Zealand white rabbits, ventilated with volume-control, were each allocated to six dosing events where each dosing event was randomly allocated to one of two dosing strategies: a control group - given a sham dose of air (10 mL/kg) over 20 min; or a partial liquid ventilation group - given 10 mL/kg FC-77 slowly over 20 min. Data were recorded for 1 min before and 30 min after the start of each dosing event. No adjustment of ventilation (except fraction of inspired oxygen) was allowed during each dosing event. There were no significant changes over time and no differences between groups for carotid blood flow (P = 0.48 at the end of the dose). There were slight increases in cortical cerebral blood flow in both groups; there was no statistically significant difference between groups (P = 0.56 at end dose and P = 0.49 at time of maximum difference). There was no difference between groups for the variability in carotid blood flow or cortical cerebral blood flow. Cerebral blood flow was not significantly increased during administration of a dose of 10 mL/kg of perfluorocarbon during commencement of partial liquid ventilation when using volume-controlled ventilation.

Effects of mechanical ventilation method on inflammatory factors and pulmonary surfactant associated protein A of bronchoalveolar lavage fluid in newborn piglets with acute lung injury

Objective To investigate the effects of 3 different ventilation methods, including conventional mechanical ventilation (CMV), high frequency oscillatory ventilation(HFOV) and partial liquid ventilation (PLV), on the changes of inflammatory factors and pulmonary surfactant associated protein A(SP-A) in bronchoalveolar lavage fluid(BALF) in newborn piglets with acute lung injury(ALI). Methods Twenty-four newborn piglets, no more than 3 days old, were enrolled.After ALI made with saline lavage(38 ℃, 35 mL/kg), newborn piglets were randomly assigned to 4 groups: control group (n=6, no ventilation), CMV group(n=6), HFOV group(n=6), and PLV group(n=6). Piglets were sacrificed after being ventilated for 24 h. Tumor necrosis factor-α(TNF-α), interleukin-8(IL-8), interleukin-1(IL-1) and SP-A in BALF were measured quantitatively by using enzyme-linked immunosorbent assay. Results In 3 groups using different ventilation methods, the population mean of TNF-α, IL-8, IL-1 and SP-A were statistically diffe-rent(all P=0.000). SP-A in PLV group and HFOV group were higher than that in CMV group (all P<0.05), while IL-8, IL-1 and TNF-α in PLV group were lower than those in CMV group (all P<0.05), IL-8 and TNF-α in PLV group were lower than those in HFOV group (all P<0.05), IL-8 and TNF-α in HFOV group were lower than those in CMV group (all P<0.05). Conclusions Pulmonary inflammatory reaction was different in 3 ventilation groups.Compared with CMV and HFOV, PLV attenuated inflammatory reaction, so it could increase the expression of SP-A and decrease the degradation of SP-A. Key words: Mechanical ventilation method; Bronchoalveolar lavage fluid; Inflammatory factor; Pulmonary surfactant associated protein A

Partial liquid ventilation for the prevention of mortality and morbidity in paediatric acute lung injury and acute respiratory distress syndrome.

Acute lung injury and acute respiratory distress syndrome are syndromes of severe respiratory failure. Children with acute lung injury or acute respiratory distress syndrome have high mortality and the survivors have significant morbidity. Partial liquid ventilation is proposed as a less injurious form of respiratory support for these children. Uncontrolled studies in adults have shown improvements in gas exchange and lung compliance with partial liquid ventilation. A single uncontrolled study in six children with acute respiratory syndrome showed some improvement in gas exchange during three hours of partial liquid ventilation. This review was originally published in 2004, updated in 2009 and again in 2012. To assess whether partial liquid ventilation reduces mortality or morbidity, or both, in children with acute lung injury or acute respiratory distress syndrome. In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 11); CINAHL (Cumulative Index to Nursing & Allied Health Literature) via Ovid (1982 to November 2011); Ovid MEDLINE (1950 to November 2011); and Ovid EMBASE (1982 to November 2011). The search was last performed in August 2008. We included randomized controlled trials (RCTs) which compared partial liquid ventilation with other forms of ventilation in children (aged 28 days to 18 years) with acute lung injury or acute respiratory distress syndrome. Trials had to report one or more of the following: mortality; duration of mechanical ventilation, respiratory support, oxygen therapy, stay in the intensive care unit, or stay in hospital; infection; long-term cognitive impairment, neurodevelopmental progress, or other long-term morbidities. We independently evaluated the quality of the relevant studies and extracted the data from the included studies. Only one study enrolling 182 patients (reported as an abstract in conference proceedings) was identified and found eligible for inclusion; the authors reported only limited results. The trial was stopped prematurely and was, therefore, under-powered to detect any significant differences and at high risk of bias. The only available outcome of clinical significance was 28-day mortality. There was no statistically significant difference between groups, with a relative risk for 28-day mortality in the partial liquid ventilation group of 1.54 (95% confidence interval 0.82 to 2.9). There is no evidence from RCTs to support or refute the use of partial liquid ventilation in children with acute lung injury or acute respiratory distress syndrome. Adequately powered, high quality RCTs are still needed to assess its efficacy. Clinically relevant outcome measures should be assessed (mortality at discharge and later, duration of both respiratory support and hospital stay, and long-term neurodevelopmental outcomes). The studies should be published in full.

Effect of Surfactant and Partial Liquid Ventilation Treatment on Gas Exchange and Lung Mechanics in Immature Lambs: Influence of Gestational Age

ObjectivesSurfactant (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.SettingExperimental Neonatal Respiratory Physiology Research Unit, Cruces University Hospital.DesignProspective, randomized study using sealed envelopes.Subjects36 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.InterventionsAll 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 ResultsCardiovascular 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.ConclusionSF therapy response was more effective in the older gestational age group whereas the effectiveness of PLV therapy was not gestational age dependent.

60 Comparison Between Aerosolized Perfluorocarbon and Partial Liquid Ventilation in Preterm Lambs With Severe Respiratory Distress Syndrome

Background and aimPerfluorocarbon (PFC) aerosolization is feasible; however, it is unknown whether aerosolization is better than Partial Liquid Ventilation (PLV).Methods18 preterm lambs were randomly assigned to receive aerosolized PFC (10...

The effects of perfluorocarbon dosing strategy on cerebral blood flow when starting partial liquid ventilation: A randomized, controlled, experimental study

Introduction: Partial liquid ventilation may benefit the lung disease in preterm neonates but intratracheal instillation of perfluorocarbon increases cerebral blood flow and may cause brain injury. We aimed to determine if the effects of perfluorocarbon administration on cerebral blood flow vary by dose-volume, rate of administration, endotracheal tube portal of entry, or closely targeting PaCO2. Methods: Forty-two dosing events (in eleven rabbits) were randomised to different dosing strategies, including a sham (i.e., placebo/control) dose of air over 20 min, 20 mL/kg of perfluorocarbon slowly over 20 min, 10 mL/kg of perfluorocarbon slowly over 20 min, 10 mL/kg of perfluorocarbon moderately fast over 10 min, 10 mL/kg of perfluorocarbon rapidly over 5 min, 10 mL/kg of perfluorocarbon slowly over 20 min via the endotracheal tube tip lumen (as opposed to the proximal end of the tube used in all other groups), or 10 mL/kg of perfluorocarbon slowly over 20 min whilst targeting a PaCO2 of 45 - 50 mmHg. Blood gases, haemodynamics, cortical cerebral blood flow and carotid flow were recorded continuously for 30 minutes from the start of each dose. Results: Carotid flow increased with 20 mL/kg perfluorocarbon and cortical cerebral blood flow was significantly more variable. Carotid and cortical cerebral blood flow increased using 10 mL/kg or 20 mL/kg with no difference between the two dose-volumes. There was no difference in cerebral blood flow by rate of administration, but carotid blood flow was more variable during slow administration. There were no differences in the increase in cerebral blood flow by portal of entry. If PaCO2 was maintained between 45 - 50 mmHg there was no increase in cerebral blood flow and there was less variable carotid flow. Conclusions: Cerebral blood flow increases with perfluorocarbon dosing. This occurs regardless of the dose-volume of perfluorocarbon. These effects were mitigated by closely targeting PaCO2.

Cardiopulmonary function and oxygen delivery during total liquid ventilation

Total liquid ventilation (TLV) with perfluorocarbons has shown to improve cardiopulmonary function in the injured and immature lung; however there remains controversy over the normal lung. Hemodynamic effects of TLV in the normal lung currently remain undetermined. This study compared changes in cardiopulmonary and circulatory function caused by either liquid or gas tidal volume ventilation. In a prospective, controlled study, 12 non-injured anesthetized, adult New Zealand rabbits were primarily conventionally gas-ventilated (CGV). After instrumentation for continuous recording of arterial (AP), central venous (CVP), left artrial (LAP), pulmonary arterial pressures (PAP), and cardiac output (CO) animals were randomized into (1) CGV group and (2) TLV group. In the TLV group partial liquid ventilation was initiated with instillation of perfluoroctylbromide (12 ml/kg). After 15 min, TLV was established for 3 hr applying a volume-controlled, pressure-limited, time-cycled ventilation mode using a double-piston configured TLV. Controls (CGV) remained gas-ventilated throughout the experiment. During TLV, heart rate, CO, PAP, MAP, CVP, and LAP as well as derived hemodynamic variables, arterial and mixed venous blood gases, oxygen delivery, PVR, and SVR did not differ significantly compared to CGV. Liquid tidal volumes suitable for long-term TLV in non-injured rabbits do not significantly impair CO, blood pressure, and oxygen dynamics when compared to CGV.

Electrical Impedance Tomography in Acute Respiratory Distress Syndrome

Electrical impedance tomography (EIT) is an emerging new imaging modality not yet routinely used in a clinical setting. The generation of EIT scans is based on the non-invasive measurement of electrical properties of tissues which does not require the use of radiation. Thoracic EIT examinations have been shown to track changes in regional lung volumes at scan rates of up to 40-50 scans/s. Experimental and clinical studies indicate the potential of EIT in monitoring regional lung ventilation and aeration at the bedside. Mechanically ventilated patients with acute lung injury and acute respiratory distress syndrome (ARDS) might benefit from possible continuous monitoring of their regional lung function by EIT which could be used to optimise the ventilator settings and minimise the ventilator-induced lung injury. This review explains the measuring principle of EIT and the analysis of regional EIT signals which allow the assessment of regional lung ventilation, aeration and potentially also lung perfusion. Protective lung ventilation using low tidal volumes and adequate positive end-expiratory pressures, recruitment manoeuvres, surfactant administration, prone posture, restricted fluid administration, assisted ventilation allowing spontaneous breathing, partial liquid ventilation, administration of pulmonary vasoactive, anti-inflammatory and antioxidant agents are used or considered in the management of ARDS patients. EIT is capable of monitoring the pulmonary effects of many of these therapeutic procedures. This is documented by examples from experimental and clinical EIT studies and by references to relevant EIT literature. The perspectives and limitations of EIT monitoring are also addressed.

1332 Effect of Surfactant and Partial Liquid Ventilation Treatment on Cerebral Haemodynamic and Oxigenation in Premature Lambs

Background: Surfactant (SF) therapy in RDS hasreduced mortality and morbidity in preterm infants. Although adverse-effects seem to be moderate, fluctuation in cerebral circulation has beenobserved. Cerebral haemodynamic changes duringpartial-liquid-ventilation (PLV) have not been welldescribed. Aim: To evaluate the effect of SF and PLV treatmenton oxygenation and on cerebral haemodynamic inpremature lambs with RDS. Methods: 18 preterm lambs (80-90%GE) wererandomly assigned to: SF-Group, receivedCurosurf®(175mg/kg), PLV-Group, treated withperfluorocarbon(30ml/kg) or Control-Group. Systemic-arterial-pressure (SAP), heart rate(HR), oxygenation-index (OI) and arterial/alveolar-index(a/ADO2) were determined during 3hours. Regionalcerebral-blood-flow (RCBF) was determined bymicrospheres-technique at foetal point (F), 1h andat 3h. Cerebral cortexes and periventicular zones(striatum, thalamus, hypothalamus, hippocampus)were grouped. Mean±SEM;Two-factor-ANOVA, p 70, a/ADO2< 0.1), that wasmaintained stable in Control-Group throughoutthe experiment. SF and PLV treatments showedsignificant improvement of gas exchange (IO:6±2and a/ADO2:0.38±0.05, at1h). However, only SFtreatment sustained this improvement along thetime. HR and SAP remained stable. Table Conclusion: In SF and PLV treatment carefulmonitoring of pulmonary and cerebral haemodynamicstatus and cautious corrections of ventilator settingsare mandatory to avoid alterations of RCBF. Supported:GV2007111046-FIS070733.

Effect of the dose volume of perfluorocarbon when starting partial liquid ventilation

Very preterm neonates are prone to brain injury if cerebral blood flow fluctuates. Partial liquid ventilation (PLV) may benefit any lung disease but giving 30 mL/kg of perfluorocarbon when starting PLV increases cortical cerebral blood flow velocity. We aimed to determine if varying the initial dose of perfluorocarbon alters the effect on cerebral blood flow velocity when starting PLV. In this randomised, controlled trial with historical comparison 24 preterm lambs received one of three loading doses of intratracheal perfluorocarbon liquid over 20 min when starting PLV: 20, 30 or 40 mL/kg. Data on respiratory mechanics, haemodynamics and cerebral blood flow velocity, measured with laser Doppler, were collected continuously for 30 min from the start of dosing. Cortical cerebral blood flow velocity increased over time in all three groups (two-way ANOVA, P= 0.007). There was no difference between groups (two-way ANOVA, P= 0.26). There was no difference between groups in cortical cerebral blood flow velocity variability (P= 0.68), blood pressure (P= 0.96) or heart rate (P= 0.46). The was no statistically significant difference in PaCO(2) between groups measured at baseline and at 30 min after starting PLV (P= 0.51). Cortical cerebral blood flow velocity and its variability are not affected by varying doses of tracheal perfluorocarbon (20, 30 or 40 mL/kg) at the start of PLV in preterm lambs.

Semi-fluorinated alkanes as carriers for drug targeting in acute respiratory failure

Partial liquid ventilation (PLV) with perfluorocarbons may cause pulmonary recruitment in acute lung injury (ALI). Semi-fluorinated alkanes (SFAs) provide biochemical properties similar to perfluorocarbons. Additionally, SFAs are characterized by increased lipophilicity. Therefore, SFA-PLV may be considered for deposition of certain therapeutic drugs into atelectatic lung areas. In this experimental study SFA-PLV was evaluated to demonstrate feasibility, pulmonary recruitment, and efficacy of drug deposition. Feasibility of SFA-PLV was determined in pigs with and without experimental ALI. Animals were randomized to PLV with SFAs up to a cumulative amount of 30 mL·kg−1 or to conventional mechanical ventilation. Pulmonary recruitment effects were determined by analyzing ventilation-perfusion distributions. Efficacy of intrapulmonary drug deposition was evaluated in further experiments by measuring drug serum concentrations in the course of PLV with SFA-dissolved α-tocopherol and ibuprofen. Increasing SFA doses caused progressive reduction of intrapulmonary shunt in animals with ALI, indicating pulmonary recruitment. PLV with SFA-dissolved α-tocopherol had no effect on serum levels of α-tocopherol, whereas PLV with SFA-dissolved ibuprofen caused a rapid increase of serum levels of ibuprofen. The authors conclude that SFA-PLV is feasible and causes pulmonary recruitment in ALI. Effectiveness of drug deposition in the lung obviously depends on the partitioning drugs out of the SFA phase into blood.

Regional overdistension identified with electrical impedance tomography in the perflubron-treated lung

Regional lung overdistension occurring during high frequency oscillatory ventilation (HFOV) and partial liquid ventilation (PLV) was investigated in a prospective animal trial using 18 mechanically ventilated Yorkshire swine under general anesthesia. Lung injury was induced with saline lavage and augmented using large tidal volumes. Electrical impedance tomography (EIT) and regional lung histopathology were used to identify regional lung overdistension during HFOV. Lung injury was quantified using a histopathologic lung injury score. The animals were randomized to three groups (n = 6 animals in each group): a control group and two dose groups of perfluorooctyl bromide (PFOB) (PFOB-Lo 1.5 ml kg−1 and PFOB-Hi 3 ml kg−1). The nimals were transitioned from conventional ventilation to HFOV, and a slow inflation-deflation maneuver was performed by changing mean airway pressure (Paw) by 5 cmH2O every 15 min to a maximum Paw of 40 cmH2O. In dependent lung areas, the PFOB-Hi (3 ml kg−1) group, in comparison with the control group, was associated with significantly greater alveolar overdistension seen on lung histopathology (P < 0.001 compared to control), a decreased mean impedance (P < 0.05 compared to the control group) and a decreased ventilation-induced impedance change during HFOV (P < 0.05 compared to the control group). We conclude that treatment with PFOB-Hi during HFOV compared to a control group in an animal model of lung injury led to regional overdistension of dependent lung areas, as evidenced by increased alveolar overdistension on lung histopathology, decreased mean lung impedance and decreased HFOV-induced regional lung volume changes as measured by EIT.

Tracheal gas insufflation with partial liquid ventilation to treat LPS‐induced acute lung injury in juvenile piglets

Partial liquid ventilation (PLV) with perfluorocarbons (PFC) seems not superior to conventional ventilation clinically. We hypothesized that a combination of continuous tracheal gas insufflation (TGI) with protective strategy of PLV (low dose of PFC, low inflation pressure, moderate inhalation of oxygen and moderate anesthesia) would improve cardiopulmonary function in acute lung injury. Twenty-four healthy juvenile piglets were anesthetized and mechanically ventilated at PEEP of 2 cmH(2)O with a peak inspiratory pressure of 10 cmH(2)O and FIO(2) of 0.4. The piglets were challenged with lipopolysaccharide and randomly assigned to four groups (n = 6 each): (1) mechanical ventilation alone (MV); (2) PLV with perfluorodecalin (10 ml/kg); (3) TGI with continuous airway flow 2 L/min; and (4) combination of PLV and TGI. The outcome was assessed functionally and histologically. All treatments except MV improved pH, PaO(2)/FIO(2), PaCO(2), ventilation efficacy index (VEI) and tidal volume. Both PLV-associated treatments also improved heart rate, respiratory rate, pulse contour cardiac output, systemic vascular resistance, dynamic lung compliance, mean airway resistance and mean airway pressure. The combination group resulted in higher PaO(2)/FIO(2), VEI and a better lung histology score than any other treatments. The new protective strategy may provide a better treatment for sepsis-induced acute lung injury.

Partial liquid ventilation : ガス交換のメカニズムとその問題点

Partial liquid ventilation : ガス交換のメカニズムとその問題点

Ventilation-Perfusion Ratio in Perflubron During Partial Liquid Ventilation

Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detected Pao(2). We investigated this approach by numerical simulations and applied it to quantify local Va/Q in the perfluorocarbons during partial liquid ventilation. Numerical simulations were performed to analyze the sensitivity of the Va/Q calculation and to compare this approach with another one proposed by Rizi et al. in 2004 (Magn Reson Med 2004;52:65-72). Experimentally, the method was used during partial liquid ventilation in 7 anesthetized pigs. The Pao(2) distribution in intraalveolar perflubron was measured by fluorine-19 MRI. Respiratory gas fractions together with arterial and mixed venous blood samples were taken to quantify oxygen partial pressure and content. Using the Fick principle, the local Va/Q was estimated. The impact of gravity (nondependent versus dependent) of perflubron dose (10 vs 20 mL/kg body weight) and of inspired oxygen fraction (Fio(2)) (0.4-1.0) on Va/Q was examined. In numerical simulations, the Fick principle proved to be appropriate over the Va/Q range from 0.02 to 2.5. Va/Q values were in acceptable agreement with the method published by Rizi et al. In the experimental setting, low mean Va/Q values were found in perflubron (confidence interval [CI] 0.08-0.29 with 20 mL/kg perflubron). At this dose, Va/Q in the nondependent lung was higher (CI 0.18-0.39) than in the dependent lung regions (CI 0.06-0.16; P = 0.006; Student t test). Differences depending on Fio(2) or perflubron dose were, however, small. The results show that derivation of Va/Q from local Po(2) measurements using fMRI in perflubron is feasible. The low detected Va/Q suggests that oxygen transport into the perflubron-filled alveolar space is significantly restrained.

Systemic perfluorohexane attenuates lung injury induced by lipopolysaccharide in rats: the role of heme oxygenase-1

Clinical trials with partial liquid ventilation demonstrate improvement in oxygenation, as well as some adverse side effects linked to the application of liquid perfluorocarbons (PFCs) during liquid ventilation. Thus, we examined the effects of systemic administration of PFC on acute lung injury (ALI) induced by lipopolysaccharide (LPS) and its effects on heme oxygenase-1 (HO-1), a compound that provides potent cytoprotection against lung injury.Rats were assigned to one of six groups (n=8). Thirty minutes after they were challenged with LPS aerosol inhalation, perfluorohexane was given intraperitoneally every two hours. Ten hours after LPS inhalation, bronchoalveolar lavage fluid (BALF) and lung tissue were obtained for enzyme linked immunosorbent assay, histologic, and Western-blot analyses. The results showed that perfluorohexane significantly decreased the wet to dry weight ratio, malondialdehyde (MDA) production, and myeloperoxidase (MPO) activity in the lung tissue. Also, perfluorohexane reduced the total protein content and levels of tumor necrosis factor-α (TNF-α) but increased the levels of the anti-inflammatory cytokine interleukin-10 (IL-10) in the BALF, resulting in decreased pulmonary edema and the infiltration of neutrophils into the lung tissues of LPS-treated rats. Furthermore, perfluorohexane increased HO-1 protein production and stimulated HO-1 activity in the lung tissue. Pre-treatment with Zinc protoporphyrin IX, an inhibitor of HO-1, decreased the protective effects of perfluorohexane in rats.In summary, systemic perfluorohexane alleviates LPS-induced lung injury in rats, and HO-1 may be involved in the mechanism of this reduction.

Perfluorocarbon Dosing when Starting Partial Liquid Ventilation: Haemodynamics and Cerebral Blood Flow in Preterm Lambs

Background: Very preterm neonates can have severe lung disease and are prone to brain injury if cerebral blood flow fluctuates. Partial liquid ventilation (PLV) may benefit the lung disease, but it is unknown whether the administration of intratracheal perfluorocarbon when starting PLV affects haemodynamics or cerebral blood flow. Objectives: To determine if haemodynamics or cerebral blood flow are affected in preterm lambs receiving a dose of perfluorocarbon when starting PLV. Methods: Sixteen preterm lambs were randomised to either PLV or conventional mechanical ventilation. An intratracheal loading dose of 30 ml/kg of perfluorocarbon liquid (PLV group) or air (sham group) was instilled over 20 min. Data were collected continuously for 30 min from the start of dosing. Results: Cortical cerebral blood flow velocity, measured continuously with laser Doppler, was increased in the PLV group during the administration of perfluorocarbon and immediately thereafter (p = 0.0026); the highest mean increase in the PLV group was 27%. There was no difference in cortical cerebral blood flow variability (p = 0.96). There was a slightly lower mean arterial blood pressure in the PLV group; the heart rate did not differ between groups. The PaCO₂ was higher in the PLV group at 30 min – the difference between groups was not statistically significant (difference between means = 5.5 mm Hg, 95% confidence interval –2.7 to 13.7). Conclusions: Preterm lambs receiving a dose of tracheal perfluorocarbon at the start of PLV have an increased cortical cerebral blood flow velocity, but no change in cortical cerebral blood flow variability.

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.

Perflubron residua: 12 years following therapy

Partial liquid ventilation therapy utilizing perfluorocarbons has been used for patients with severe respiratory distress. Perfluorocarbons such as perflubron have been demonstrated to clear from the lungs shortly after therapy. We present a 13-year-old boy with residual perflubron in his lungs, 12 years following therapy with perflubron. The imaging features are important to recognize as these patients return for additional care and imaging.