Vladimir N. Kuklin

Extravascular lung water determined with single transpulmonary thermodilution correlates with the severity of sepsis-induced acute lung injury

Objective:To find out if the extravascular lung water index (EVLWI) and the derived permeability indexes determined by the single transpulmonary thermodilution technique are associated with markers of acute lung injury in human septic shock. Design:Prospective, observational study. Setting:Mixed intensive care unit of a 900-bed university hospital. Patients:Thirty-eight consecutive adult patients with septic shock and acute lung injury. Interventions:None. Measurements and Main Results:The variables were assessed over a 72-hr period and included hemodynamics, EVLWI, and pulmonary vascular permeability indexes determined with the single indicator transpulmonary thermodilution technique, lung compliance, oxygenation ratio (Pao2/Fio2), lung injury score, cell counts, and the plasma concentration of endothelin-1. At day 1, EVLWI was elevated (≥7 mL/kg) in 28 (74%) patients and correlated with lung compliance (r = −.48, p = .002), Pao2/Fio2 (r = −.50, p = .001), lung injury score (r = .46, p = .004), roentgenogram quadrants (r = .39, p = .02), and platelet count (r = −.43, p = .007). At day 3, EVLWI correlated with compliance (r = −.51, p = .002), Pao2/Fio2 (r = −.49, p = .006), and lung injury score (r = .53, p = .003). At day 3, EVLWI and pulmonary vascular permeability indexes were higher in nonsurvivors (p< .05). The plasma concentration of endothelin-1 (mean ± sd) was significantly higher in patients with elevated EVLWI (≥7 mL/kg) (3.85 ± 1.40 vs. 2.07 ± 0.38 pg/mL, respectively). Twenty-two (59%) patients died before day 28. Conclusions:In human septic shock, EVLWI demonstrated moderate correlation with markers of acute lung injury, such as lung compliance, oxygenation ratio, roentgenogram quadrants, and lung injury score. In nonsurvivors, EVLWI and permeability indexes were significantly increased at day 3. Thus, EVLWI might be of value as an indicator of prognosis and severity of sepsis-induced acute lung injury.

Extravascular lung water assessed by transpulmonary single thermodilution and postmortem gravimetry in sheep

IntroductionAcute lung injury is associated with accumulation of extravascular lung water (EVLW). The aim of the present study was to compare two methods for quantification of EVLW: transpulmonary single thermodilution (EVLWST) and postmortem gravimetric (EVLWG).MethodsEighteen instrumented and awake sheep were randomly assigned to one of three groups. All groups received Ringers lactate (5 ml/kg per hour intravenously). To induce lung injury of different severities, sheep received Escherichia coli lipopolysaccharide 15 ng/kg per min intravenously for 6 hours (n = 7) or oleic acid 0.06 ml/kg intravenously over 30 min (n = 7). A third group (n = 4) was subjected to sham operation. Haemodynamic variables, including EVLWST, were measured using a PiCCOplus monitor (Pulsion Medical Systems, Munich, Germany), and the last measurement of EVLWST was compared with EVLWG.ResultsAt the end of experiment, values for EVLWST (mean ± standard error) were 8.9 ± 0.6, 11.8 ± 1.0 and 18.2 ± 0.9 ml/kg in the sham-operated, lipopolysaccharide and oleic acid groups, respectively (P < 0.05). The corresponding values for EVLWIG were 6.2 ± 0.3, 7.1 ± 0.6 and 11.8 ± 0.7 ml/kg (P < 0.05). Ranges of EVLWIST and EVLWIG values were 7.5–21.0 and 4.9–14.5 ml/kg. Regression analysis between in vivo EVLWST and postmortem EVLWG yielded the following relation: EVLWST = 1.30 × EVLWG + 2.32 (n = 18, r = 0.85, P < 0.0001). The mean bias ± 2 standard deviations between EVLWST and EVLWG was 4.9 ± 5.1 ml/kg (P < 0.001).ConclusionIn sheep, EVLW determined using transpulmonary single thermodilution correlates closely with gravimetric measurements over a wide range of changes. However, transpulmonary single thermodilution overestimates EVLW as compared with postmortem gravimetry.

Novel endothelin receptor antagonist attenuates endotoxin-induced lung injury in sheep.

ObjectiveTo evaluate the cardiopulmonary effects of the novel endothelin receptor antagonist tezosentan in endotoxin-induced lung injury in sheep and to assess the dose response to tezosentan and endothelin-1 in healthy sheep. DesignProspective, randomized, controlled experimental study. SettingUniversity animal laboratory. SubjectsTwenty-one yearling sheep. InterventionsSeventeen awake, chronically instrumented sheep were subjected to intravenous infusion of Ringer’s lactate for 24 hrs. The animals were randomly assigned to a sham-operated group (n = 3), a lipopolysaccharide group (n = 7) receiving an intravenous infusion of Escherichia coli lipopolysaccharide 15 ng·kg−1·min−1, and a tezosentan group (n = 7) subjected to lipopolysaccharide and, from 4 hrs, an intravenous injection of tezosentan 3 mg/kg followed by infusion of 1 mg·kg−1·hr−1. In addition, four healthy sheep, exposed to an intravenous infusion of endothelin-1 at 20 ng·kg−1·min−1, after 1 hr received tezosentan in stepwise increasing doses of 0.5, 1, and 2 mg·kg−1·hr−1 that were maintained for 1 hr each. After a 4-hr recovery, the sheep received infusions of tezosentan at the same dose rates as a pretreatment to endothelin-1. Measurements and Main ResultsIn the sham-operated sheep, all cardiopulmonary variables remained unchanged. Lipopolysaccharide caused pulmonary hypertension, increased extravascular lung water index, and induced arterial hypoxemia. Tezosentan decreased the increments in pulmonary vascular resistance and extravascular lung water index by as much as 60% and 70%, respectively. In parallel, tezosentan ameliorated arterial hypoxemia, increased cardiac index, attenuated the decrease in stroke volume index, and reduced systemic vascular resistance. Compared with the lipopolysaccharide group, tezosentan further increased plasma concentrations of endothelin-1. In healthy animals, the administration of endothelin-1 induced systemic and pulmonary hypertension, increased extravascular lung water index, and evoked bradycardia and a decrease in cardiac index. These changes were attenuated by tezosentan infused at 1 and 2 mg·kg−1·hr−1. ConclusionsIn an ovine model of endotoxin-induced lung injury, tezosentan ameliorates pulmonary hypertension, lung edema, cardiac dysfunction, and arterial hypoxemia. Tezosentan counteracts the hemodynamic effects of endothelin-1 in a dose-dependent manner.

Extravascular lung water after pneumonectomy and one-lung ventilation in sheep

Objective:To compare the single thermodilution and the thermal-dye dilution techniques with postmortem gravimetry for assessment of changes in extravascular lung water after pneumonectomy and to explore the evolution of edema after injurious ventilation of the left lung. Design:Experimental study. Setting:University laboratory. Subjects:A total of 30 sheep weighing 35.6 ± 4.6 kg. The study included two parts: a pneumonectomy study (n = 18) and an injurious ventilation study (n = 12). Methods:Sheep were anesthetized and mechanically ventilated with an Fio2 of 0.5, tidal volume of 6 mL/kg, and positive end-expiratory pressure of 2 cm H2O. In the pneumonectomy study, sheep were assigned to right-sided pneumonectomy (n = 7), left-sided pneumonectomy (n = 7), or lateral thoracotomy only (sham operation, n = 4). In the injurious ventilation study, right-sided pneumonectomy was followed by ventilation with a tidal volume of 12 mL/kg and positive end-expiratory pressure of 0 cm H2O (n = 6) or by ventilation with a tidal volume of 6 mL/kg and positive end-expiratory pressure of 2 cm H2O for 4 hrs (n = 6). Volumetric variables, including extravascular lung water index (EVLWI), were measured with single thermodilution (STD; EVLWISTD) and thermal-dye dilution (TDD; EVLWITDD) techniques. We monitored pulmonary hemodynamics and respiratory variables. After the sheep were killed, EVLWI was determined for each lung by gravimetry (EVLWIG). Results:In total, the study yielded strong correlations of EVLWISTD and EVLWITDD with EVLWIG (n = 30; r = .83 and .94, respectively; p < .0001). After pneumonectomy, both the left- and the right-sided pneumonectomy groups displayed significant decreases in EVLWISTD and EVLWITDD. The injuriously ventilated sheep demonstrated significant increases in EVLWI that were detected by both techniques. The mean biases (±2 sd) compared with EVLWIG were 3.0 ± 2.6 mL/kg for EVLWISTD and 0.4 ± 1.6 mL/kg for EVLWITDD. Conclusions:After pneumonectomy and injurious ventilation of the left lung, TDD and STD displayed changes in extravascular lung water with acceptable accuracy when compared with postmortem gravimetry. Ventilator-induced lung injury seems to be a crucial mechanism of pulmonary edema after pneumonectomy.

Tezosentan-induced attenuation of lung injury in endotoxemic sheep is associated with reduced activation of protein kinase C

IntroductionStudies in vitro reveal that endothelin-1 (ET-1) activates the α isoform of protein kinase C (PKC-α) in cultures of endothelial cells, thereby deranging cellular integrity. Sepsis and endotoxemia are associated with increased plasma concentrations of ET-1 that induce acute lung injury (ALI). We recently reported that non-selective ET-1 receptor blockade attenuates ALI in sheep by reducing the endotoxin-induced increase in extravascular lung water index (EVLWI). The aim of this study was to find out whether this attenuation is associated with reduced translocation of PKC-α from the cytosolic to the membrane fraction of lung tissue homogenate.MethodsSeventeen awake, instrumented sheep were randomly assigned to a sham-operated group (n = 3), a lipopolysaccharide (LPS) group (n = 7) receiving an intravenous infusion of Escherichia coli 15 ng/kg per min for 24 hours, and a tezosentan group (n = 7) subjected to LPS and, from 4 hours, an intravenous injection of tezosentan 3 mg/kg followed by infusion at 1 mg/kg per hour for the reminder of the experiment. Pulmonary micro-occlusion pressure (Pmo), EVLWI, plasma concentrations of ET-1, tumor necrosis factor-a (TNF-a), and interleukin-8 (IL-8) were determined every 4 hours. Western blotting was used to assess PKC-α.ResultsIn non-treated sheep a positive correlation was found between the plasma concentration of ET-1 and Pmo in the late phase of endotoxemia (12 to 24 hours). A positive correlation was also noticed between Pmo and EVLWI in the LPS and the LPS plus tezosentan groups, although the latter was significantly reduced in comparison with LPS alone. In both endotoxemic groups, plasma concentrations of ET-1, TNF-α, and IL-8 increased. In the LPS group, the cytosolic fraction of PKC-α decreased by 75% whereas the membrane fraction increased by 40% in comparison with the sham-operated animals. Tezosentan completely prevented the changes in PKC-α in both the cytosolic and the membrane fractions, concomitantly causing a further increase in the plasma concentrations of ET-1, TNF-α, and IL-8.ConclusionIn endotoxemic sheep, ET-1 receptor blockade alleviates lung injury as assessed by a decrease in EVLWI paralleled by a reduction in Pmo and the prevention of activation of PKC-α.

Inhaled aerosolised recombinant human activated protein C ameliorates endotoxin-induced lung injury in anaesthetised sheep

IntroductionWe recently demonstrated that intravenously infused recombinant human activated protein C (APC) attenuates ovine lipopolysaccharide (LPS)-induced lung injury. In this study, our aim was to find out whether treatment with inhaled aerosolised APC (inhAPC) prevents formation of increased lung densities and oedema and derangement of oxygenation during exposure to LPS.MethodsSheep were anaesthetised during placement of intravascular introducers. After one to four days of recovery from instrumentation, the animals were re-anaesthetised, endotracheally intubated and mechanically ventilated throughout a six-hour experiment where the sheep underwent quantitative lung computed tomography. Sheep were randomly assigned to one of three groups: a sham-operated group (n = 8) receiving inhaled aerosolised saline from two hours after the start of the experiment; a LPS group (n = 8) receiving an intravenous infusion of LPS 20 ng/kg per hour and, after two hours, inhaled aerosolised saline over the next four hours; a LPS+inhAPC group (n = 8) receiving an intravenous infusion of LPS 20 ng/kg per hour and, after two hours, aerosolised APC 48 μg/kg per hour inhaled throughout the experiment. Data were analysed with analysis of variance; P less than 0.05 was regarded as significant.ResultsAn infusion of LPS was associated with a reduction of well-aerated lung volume and a rapid fall in arterial oxygenation that were both significantly antagonised by inhaled APC. Pulmonary vascular pressures and extravascular lung water index increased significantly during exposure to LPS, but inhaled APC had no effect on these changes.ConclusionsInhalation of aerosolised APC attenuates LPS-induced lung injury in sheep by preventing a decline in the volume of aerated lung tissue and improving oxygenation.

Recombinant human activated protein C attenuates endotoxin-induced lung injury in awake sheep.

IntroductionAcute lung injury often complicates severe sepsis. In Gram-negative sepsis, bacterial endotoxin activates both coagulation and inflammation. Enhanced lung vascular pressures and permeability, increased extravascular lung water content and deteriorated gas exchange characterize ovine endotoxin-induced lung injury, a frequently used model of acute lung injury. Recombinant human activated protein C (rhAPC), with its anticoagulant, anti-inflammatory, fibrinolytic and antiapoptotic effects, reportedly reduces the respirator-dependent days and the mortality of patients with severe sepsis. We speculate whether rhAPC antagonizes endotoxin-induced lung injury in sheep.MethodsTwo groups of sheep were exposed to Escherichia coli endotoxin (lipopolysaccharide) 15 ng/kg/minute intravenously from 0 to 24 hours; one group received only lipopolysaccharide throughout (n = 8), and the other group received lipopolysaccharide in combination with rhAPC 24 μg/kg/hour from 4 to 24 hours (n = 9). In addition, one group received rhAPC as above as the only intervention (n = 4), and four sham-operated sheep were used for determination of the α and ε isoforms of protein kinase C in pulmonary tissue. Data were assessed by one-way analysis of variance for repeated measurements. Biochemical data were analyzed using Students t test, or using the Mann–Whitney U test when appropriate.ResultsInfusion of endotoxin caused lung injury, manifested by increments in pulmonary artery pressure, in pulmonary micro-occlusion pressure, in pulmonary vascular downstream resistance, in pulmonary vascular permeability index, in extravascular lung water index and in deterioration of oxygenation that were all attenuated by infusion of rhAPC. Endotoxemia led to changes in inflammation and coagulation, including pulmonary neutrophil accumulation paralleled by increased TNFα and decreased protein C and fibrinogen in animal plasma, which all improved following infusion of rhAPC. Moreover, rhAPC prevented the translocation of protein kinase C α and ε isoforms from the cytosolic fraction of lung tissue extracts.ConclusionIn awake sheep, rhAPC alleviates endotoxin-induced lung injury – as characterized by improvements of oxygenation, coagulation and inflammation, as well as by reversal of pulmonary hemodynamic and volumetric changes.

Recombinant human activated protein C ameliorates oleic acid-induced lung injury in awake sheep

IntroductionAcute lung injury (ALI) may arise both after sepsis and non-septic inflammatory conditions and is often associated with the release of fatty acids, including oleic acid (OA). Infusion of OA has been used extensively to mimic ALI. Recent research has revealed that intravenously administered recombinant human activated protein C (rhAPC) is able to counteract ALI. Our aim was to find out whether rhAPC dampens OA-induced ALI in sheep.MethodsTwenty-two yearling sheep underwent instrumentation. After 2 days of recovery, animals were randomly assigned to one of three groups: (a) an OA+rhAPC group (n = 8) receiving OA 0.06 mL/kg infused over the course of 30 minutes in parallel with an intravenous infusion of rhAPC 24 mg/kg per hour over the course of 2 hours, (b) an OA group (n = 8) receiving OA as above, or (c) a sham-operated group (n = 6). After 2 hours, sheep were sacrificed. Hemodynamics was assessed by catheters in the pulmonary artery and the aorta, and extravascular lung water index (EVLWI) was determined with the single transpulmonary thermodilution technique. Gas exchange was evaluated at baseline and at cessation of the experiment. Data were analyzed by analysis of variance; a P value of less than 0.05 was regarded as statistically significant.ResultsOA induced profound hypoxemia, increased right atrial and pulmonary artery pressures and EVLWI markedly, and decreased cardiac index. rhAPC counteracted the OA-induced changes in EVLWI and arterial oxygenation and reduced the OA-induced increments in right atrial and pulmonary artery pressures.ConclusionsIn ovine OA-induced lung injury, rhAPC dampens the increase in pulmonary artery pressure and counteracts the development of lung edema and the derangement of arterial oxygenation.

Influence of a New “Call-Out Algorithm” for Management of Postoperative Pain and Its Side Effects on Length of Stay in Hospital: A Two-Centre Prospective Randomized Trial

Background We recently introduced the efficacy safety score (ESS) as a new “call-out algorithm” for management of postoperative pain and side effects. In this study, we report the influence of ESS recorded hourly during the first 8 hours after surgery on the mobility degree, postoperative nonsurgical complications, and length of hospital stay (LOS). Methods We randomized 1152 surgical patients into three groups for postoperative observation: (1) ESS group (n = 409), (2) Verbal Numeric Rate Scale (VNRS) for pain group (n = 417), and (3) an ordinary qualitative observation (Control) group (n = 326). An ESS > 10 or VNRS > 4 at rest or a nurses observation of pain or adverse reaction to analgesic treatment in the Control group served as a “call-out alarm” for an anaesthesiologist. Results We found no significant differences in the mobility degree and number of postoperative nonsurgical complications between the groups. LOS was significantly shorter with 12.7 ± 6.3 days (mean ± SD) in the ESS group versus 14.2 ± 6.2 days in the Control group (P < 0.001). Conclusion Postoperative ESS recording in combination with the possibility to call upon an anaesthesiologist when exceeding the threshold score might have contributed to the reductions of LOS in this two-centre study. This trial is registered with NCT02143128.