Experimental study of airway pressure release ventilation in the treatment of acute respiratory distress syndrome.

Airway pressure release ventilation (APRV) is a ventilator mode which has demonstrated potential benefits in acute respiratory distress syndrome (ARDS) patients. We therefore sought to compare relevant pulmonary data and safety outcomes of this mode to the conventional ventilation and sustained inflation. Canines admitted after intravenous injection of oleic acid requiring mechanical ventilation were randomly divided into 3 groups (n=6), namely conventional ventilation group, low tidal volume ventilation with recruitment group (LTV+SI) and APRV group. The changes of oxygenation, ventilation, airway pressure, inflammatory reaction and hemodynamics at the basic state were observed at 0, 1, 2 and 4 h during the experiment. The levels of PaO2/FiO2 in APRV group were higher than LTV+SI group at 2 and 4 h (P<0.05). In APRV group, the PCO2 levels at 1, 2 and 4 h is much lower than LTV+SI group (P<0.05). Outcome variables showed no differences between APRV, LVT+SI and conventional mechanical ventilation for plateau airway pressure (24±1 vs. 29±3 vs. 25±4), mean arterial pressure (92.9±16.5 vs. 85.8±21.4 vs. 88.7±24.4), cardiac index (4.3±1.7 vs. 3.5±1.9 vs. 3.4±2.1), ERO2 (13.4±10.3 vs. 16.1±6.8 vs. 17.6±9.1), lac (2.5±1.7 vs. 3.1±1.6 vs. 3.9±1.9), tumor necrosis factor (TNF)-α (132±11 vs. 140±6 vs. 195±13) and matrix metalloproteinase (MMP)-9. For canines sustaining acute respiratory distress syndrome requiring mechanical ventilation, APRV can significantly improve oxygenation and keep hemodynamic stability compared with LTV+SI. The results of TNF-α and MMP-9 suggest that APRV could be as protective for ARDS as LTV with recruitment group.

Effect of setting high APRV guided by expiratory inflection point of pressure-volume curve on oxygen delivery in canine models of severe acute respiratory distress syndrome.

In the present study, the effect of setting high airway pressure release ventilation (APRV) pressure guided by an expiratory inflection point of pressure-volume (PV) curve following lung recruitment maneuver (RM) on oxygen delivery (DO2) in canine models of severe acute respiratory distress syndrome (ARDS) was examined. Canine models of severe ARDS were established by intravenous injection of oleic acid. After injection of sedative muscle relaxants, a PV curve plotted using the super-syringe technique, and the pressure at lower inflection point (LIP) at the inhale branch and the pressure at the point of maximum curvature (PMC) at the exhale branch were measured. The ventilation mode was biphasic positive airway pressure (BiPAP), an inspiration to expiration ratio of 1:2, and Phigh 40 cm H2O, Plow 25 cm H2O. Phigh was decreased to 30 cm H2O after 90 sec. The dogs were randomized into 3 groups after RM, i.e., Blip group, BiPAP Plow = LIP+2 cm H2O; Bpmc group, BiPAP Plow = PMC; and Apmc group. In the APRV group, Phigh was set as PMC, with an inspiratory duration of 4 sec and expiratory duration of 0.4 sec. PMC was 18±1.4 cm H2O, and LIP was 11±1.3 cm H2O. Thirty seconds after RM was stabilized, it was set as 0 h. Hemodynamics, oxygenation and DO2 were measured at 0, 1, 2 and 4 h after RM in ARDS dogs. The results demonstrated: i) cardiac index (CI) in the 3 groups, where CI was significantly decreased in the Bpmc group at 0, 1, 2 and 4 h after RM compared to prior to RM (P<0.05) as well as in the Blip and Apmc groups (P<0.05). CI in the Blip and Apmc groups was not significantly altered prior to and after RM. ii) Oxygenation at 0, 1, 2 and 4 h in the 3 groups was improved after RM and the oxygenation indices for the 3 groups at 1 and 2 h were not significantly different (P>0.05). However, the oxygenation index in the Blip group at 4 h was significantly lower than those at 0 h for the Apmc and Bpmc groups (P<0.05). Oxygenation for the Apmc group at 4 h was higher than that for the Blip and Bpmc groups (P<0.05). Oxygenation for the Bpmc group was lower than that at 0 h, although the difference was not significant (P>0.05). iii) DO2 in at 0, 1, 2 and 4 h in the Bpmc group was significantly lower than that in the Blip and Apmc groups, and not significantly improved after RM. DO2 in the Blip and Apmc groups after RM was improved as compard to that before RM and that in the Bpmc group. However, DO2 at 4 h in the Blip group was significantly lower than that at 0 h and in the Apmc group (P<0.05). DO2 at 4 h in the Apmc group was higher than that at 0 h and that in the remaining 2 groups (P<0.05). In conclusion, high APRV pressure guided at PMC of PV curve after RM significantly improved DO2 in ARDS dogs.

The Use of Limited Fluid Resuscitation and Blood Pressure-Controlling Drugs in the Treatment of Acute Upper Gastrointestinal Hemorrhage Concomitant with Hemorrhagic Shock.

The aim of this study was to evaluate the usefulness of the limited fluid resuscitation regimen combined with blood pressure-controlling drugs in treating acute upper gastrointestinal hemorrhage concomitant with hemorrhagic shock. A total of 51 patients were enrolled and divided into a group that received traditional fluid resuscitation group (conventional group, 24 patients) and a limited fluid resuscitation group (study group, 27 patients). Before and after resuscitation, the blood lactate, base excess, and hemoglobin values, as well as the volume of fluid resuscitation and resuscitation time were examined. Compared with conventional group, study group had significantly better values of blood lactate, base excess, and hemoglobin (all p < 0.05). In addition, both volume of fluid resuscitation and resuscitation time were significantly (p < 0.05) lower in these patients. Limited fluid resuscitation combined with blood pressure-controlling drugs effectivelyxxx maintains blood perfusion of vital organs, improves whole body perfusion indicators, reduces the volume of fluid resuscitation, and achieves better bleeding control and resuscitation effectiveness.

Combined use of non-biological artificial liver treatments for patients with acute liver failure complicated by multiple organ dysfunction syndrome.

BACKGROUND: Acute liver failure (ALF) caused by viral and non-viral hepatitis is often accompanied with severe metabolic disorders, the accumulation of toxic substances and continuous release and accumulation of a large number of endogenous toxins and inflammatory mediators. The present study aimed to investigate the effects of various combined non-biological artificial liver treatments for patients with acute liver failure (ALF) complicated by multiple organ dysfunction syndrome (MODS). METHODS: Thirty-one patients with mid- or late-stage liver failure complicated by MODS (score 4) were randomly divided into three treatment groups: plasmapheresis (PE) combined with hemoperfusion (HP) and continuous venovenous hemodiafiltration (CVVHDF), PE+CVVHDF, and HP+CVVHDF, respectively. Heart rate (HR) before and after treatment, mean arterial pressure (MAP), respiratory index (PaO2/FiO2), hepatic function, platelet count, and blood coagulation were determined. RESULTS: Significant improvement was observed in HR, MAP, PaO2/FiO2, total bilirubin (TBIL) and alanine aminotransferase (ALT) levels after treatment (P<0.05). TBIL and ALT decreased more significantly after treatment in the PE+CVVHDF and PE+HP+CVVHDF groups (P<0.01). Prothrombin time (PT) and albumin were significantly improved only in the PE+CVVHDF and PE+HP+CVVHDF groups (P<0.05). TBIL decreased more significantly in the PE+HP+CVVHDF group than in the HP+CVVHDF and PE+CVVHDF groups (P<0.05). The survival rate of the patients was 58.1% (18/31), viral survival rate 36.4% (4/11), and non-viral survival rate 70% (14/20). CONCLUSION: Liver function was relatively improved after treatment, but PE+HP+CVVHDF was more efficient for the removal of toxic metabolites, especially bilirubin. The survival rate was significantly higher in the patients with non-viral liver failure than in those with viral liver failure.

Hemodiafiltration combined with resin-mediated absorption as a therapy for hyperlipidemic acute pancreatitis.

The aim of this study is to investigate whether hemodiafiltration combined with resin-mediated absorption is a better therapy for hyperlipidemic acute pancreatitis. Patients (n = 67) with acute pancreatitis treated in ICU from January 2009 to December 2012 were included in this study. Seven of these 67 cases were diagnosed hyperlipidemic acute pancreatitis (HLAP). All the 7 HLAP patients went through fast, gastrointestinal decompression, anti-shock treatment, inhibition of pancreatic secretion, antiseptic treatments, and hemoperfusion (HP) combined with continuous veno venous hemodiafiltration (CVVHDF). After one round of treatment by resin adsorption, there was a significant decrease in serum triglycerides (TG) (29.78 %) and total cholesterol (TC) (24.02 %) levels (p < 0.01). TG and TC levels dropped by 49.02 and 37.66 %, respectively, after 1-day treatment of HP + CVVHDF; by 62.81 and 47.37 % on day 2 post-treatment; and by 69.57 and 49.47 % on day 3 post-treatment. All the 7 patients survived. The average time spent in the ICU was 7 ± 3.8 days, and the average duration of hospitalization was 19 ± 15.1 days. Our results show that hemoperfusion combined with hemodiafiltration is an efficient treatment as this approach can reduce plasma lipid levels effectively and reduce the risk of acute pancreatitis due to hyperlipidemia.

Efficacy of various combined blood purification techniques for treating patients with non-viral acute liver failure.

We sought to study the clinical efficacy of various combined blood purification techniques in patients with non-viral acute liver failure complicated by multiple organ dysfunction syndrome (MODS). For this purpose, 19 patients diagnosed of mid- or late-stage liver failure with MODS score-4 were randomly divided into 3 treatment groups of PE+HP+CVVHDF, PE+CVVHDF, and HP+CVVHDF, respectively. Pre- and post-treatment heart rate (HR), mean arterial pressure (MAP), arterial blood gases (pH, PaO2, and PaCO2), hepatic function, platelet count, and blood coagulation were determined. The data show significant improvement in HR, MAP, PaO2/FiO2, total bilirubin (TBIL), and alanine aminotransferase (ALT) levels after treatment (P < 0.05). TBIL decreased more significantly after treatment in PE+CVVHDF and PE+HP+CVVHDF groups (P < 0.01). Significant improvement in prothrombin time and albumin was observed only in PE+CVVHDF and PE+HP+CVVHDF groups (P < 0.05). The decrease of TBIL and improvement of PaO2/FiO2 ratio were more pronounced in PE+HP+CVVHDF than in HP+CVVHDF group (P < 0.05). To conclude, liver function was relatively improved by all the three combined blood purification techniques used; however, PE+HP+CVVHDF approach was found more efficient in the removal of toxic metabolites, especially bilirubin. The data suggest that the combined blood purification techniques used were effective and involved minor side effects.

[Effects of combination of midazolam and propofol on anterograde amnesia in critical patients].

OBJECTIVE: To observe the effects of sedation with midazolam and propofol on anterograde amnesia in critical patients. METHODS: Sixty selected patients on mechanical ventilation in intensive care unit (ICU) were randomly divided into three subgroups (propofol, midazolam, and midazolam and propofol combination group), with 20 cases in each group. Patients who were awakened from sedation were showed with a card depicted with different colors, figures and numbers. When patients were totally conscious after weaning from mechanical ventilation,the influence of the different methods of sedation on anterograde amnesia of these critically ill patients was assessed. RESULTS: (1) 70%, 95% and 90% of patients manifested amnesia in propofol, midazolam and the combination group, respectively. All the patients recovered their memory immediately in 30 minutes after withdrawal of the sedatives. (2) When midazolam was compared with propofol and combination group, time of onset was obviously prolonged after an intravenous injection of a load dose in midazolam group [(2.7+/-1.1) minutes and (3.1+/-1.3) minutes vs. (5.1+/-2.8) minutes], also was time of extubation after regaining of consciousness [(0.7+/-0.2) hour and (1.2+/-0.6) hours vs. (2.7+/-0.3) hours, all P<0.01]. There was no significant difference between propofol group and the combination group in time of onset and extubation (both P>0.05). (3) Cost of propofol [(2,100+/-125) yuan] was 75% higher than that of midazolam [(1,200+/-112) yuan, P<0.01], but cost of sedatives in the combination group [(1,300+/-132) yuan] was similar to that in midazolam group (P>0.05). CONCLUSION: Combination of midazolam and propofol can not only ensure anterograde amnesia in critical patients, reduce drug dosage and adverse reactions, but also can help reduce the hospital expenses. This method may be a better sedation program in ICU.

[Effect of recruitment maneuver on alveolar epithelium barrier in rat with acute lung injury].

OBJECTIVE: To evaluate the influence of recruitment maneuver (RM) on alveolar epithelium barrier in rat with acute lung injury (ALI). METHODS: The ALI rats model were replicated by lipopolysaccharide iv injection. Sustained inflation (SI), as a method of RM, was applied by airway pressure of 30 cm H(2)O for 30 seconds. Forty-eight male SD rats were randomly divided into four groups: normal group, ALI group, low tidal volume (V(T)) group (LV group) and low V(T)+SI group (SI group). After 4 hours of mechanical ventilation, lung injury was evaluated by Smith lung injury score. Extravascular lung water (EVLW) was measured by gravimetric method. Alveolar epithelium apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL). mRNA expression of surfactant protein (SP)-C was assessed by reverse transcription polymerase chain reaction (RT-PCR). Interleukin (IL-6) and IL-10 levels in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Injury degree of lung tissues in SI group was lighter than those of ALI and LV groups under microscope. A few of apoptotic epithelial cells were observed in SI group (all P<0.05). Compared with LV group, apoptotic epithelial cells were decreased in number in SI group. Smith lung injury score and EVLW in ALI, LV and SI group were higher than those in the control group. Smith lung injury score in ALI group was significantly higher than the score in SI and LV group (both P<0.05). Smith lung injury score and EVLW of SI group were significantly lower than those of LV group (both P<0.05). There was no significant difference in EVLW between SI and ALI group. The SP-C mRNA expression was significantly lowered in ALI, LV and SI groups compared with that in control group (all P<0.05). The SP-C mRNA expression in SI group was stronger than LV group significantly (P<0.05), but not significant when compared with that of ALI group. The concentrations of IL-6 and IL-10 in BALF of ALI, LV and SI groups were significantly higher than those of control group (all P<0.05). In SI group, the concentration of IL-6 in BALF was lower than LV group (P<0.05). There was no difference in the permeability of alveolar epithelium among ALI, LV and SI groups. CONCLUSION: RM can alleviate lung tissue injury, up-regulate SP-C mRNA expression in alveolar epithelium, protect alveolar epithelium barrier and down-regulate pulmonary inflammatory mediator expression in ALI.

[Effect of lung stress index on titration of positive end-expiratory pressure at post-recruitment in three canine acute respiratory distress syndrome models].

OBJECTIVE: To investigate the relationship of lung stress index and positive end-expiratory pressure (PEEP) at post-recruitment in different canine acute respiratory distress syndrome (ARDS) models. METHODS: The ARDS models were induced by intravenous oleic acid, saline lavage and hydrochloric acid aspiration in anesthetized dogs. During volume control ventilation with constant inspiratory flow, PEEP was set to obtain a b (stress index) value between 0.9 and 1.1 (b = 1) before and post recruitment maneuver (RM). PEEP was changed to obtain b < 1 (0.6 < b < 0.8) and b > 1 (1.1 < b < 1.3). Meanwhile, the recruited volume (RV) was measured and pulmonary mechanics and gas exchange were observed. RESULTS: At b = 1 after RM, PEEP were (10.8 +/- 2.3), (12.8 +/- 1.8) and (9.2 +/- 1.8) cm H2O in the oleic acid, saline-lavaged and hydrochloric acid aspiration groups, respectively. PEEP in saline-lavaged group was higher than that in hydrochloric acid aspiration group (P < 0.05). The ratio of partial arterial oxygen tension and fraction of inspiratory oxygen (PaO(2)/FiO(2)) at b = 1 without RM was lower than those post-RM in all three groups (P < 0.05). In oleic acid group, PaO(2)/FiO(2) at b = 1 post-RM was (399 +/- 61) mm Hg, which was higher than that at b < 1 [(307 +/- 71) mm Hg], but there was no difference between those at b = 1 and b > 1. At b = 1 after RM, PaO(2)/FiO(2) in the saline-lavaged group was higher than that in acid aspiration group, but no difference between saline-lavaged group and oleic acid group was found. At b = 1 post-RM, RV were higher than that at b = 1 before RM in all three groups (P < 0.01), but there was no significant difference among three groups. At b = 1 post-RM in three groups, pulmonary compliance were higher than those at b > 1, but airway plateau pressure were lower than those at b > 1. CONCLUSIONS: Lung stress index could be a good indicator for PEEP titration at post-RM.

[Assessment of stroke volume variation and intrathoracic blood volume index on the responsiveness to volume loading in mechanically ventilated canine with hemorrhagic shock].

OBJECTIVE: To assess the significance of stroke volume variation (SVV) and intrathoracic blood volume index (ITBI) on the responsiveness to volume loading in mechanically ventilated canine with hemorrhagic shock. METHODS: Hemorrhagic shock canine model was established with the modified Wiggers' method. The heart rate (HR), mean artery pressure (MAP), central venous pressure (CVP), pulmonary artery wedge pressure (PAWP), intrathoracic blood volume index (ITBI) and stroke volume variation (SVV) were investigated by Swan-Ganz catheter or PiCCO monitor. Graded volume loading (VL) was performed. Successive responsive VLs were performed (increase in SV > 5% after VL) until continuous change in SV < 5% (unresponsive) was reached. RESULTS: Fourteen canines were studied and a total of 134 VLs were performed. In 94 VLs, an increase in SV of more than 5% was reached. In the other 40 VLs, increase in SV was less than 5%. The change of HR, MAP, ITBI, SVV in responsive were more than those of unresponsive after VL. The change of CVP, PAWP in responsive were less than those of unresponsive. Significant correlation was found between DeltaSV after VL and the baseline values of ITBI, SVV. No correlation was found between DeltaSV and HR, MAP, CVP, PAWP. Significant correlations were also found between DeltaSV and DeltaCVP, DeltaPAWP, DeltaITBI, DeltaSVV after fluid loading. No correlation was found between DeltaSV and DeltaHR, DeltaMAP. By using receiver operating characteristic analysis, the area under the curve were 0.872 for SVV and 0.689 for ITBI, more than those of HR, MAP, CVP, PAWP statistically. As SVV value of 9.5% or more will predict an increase in the SV of at least 5% in response to a VL with a sensitivity of 92.6% and a specificity of 82.5%. CONCLUSIONS: SVV and ITBI were more useful indicators than CVP and PAWP on the assessment of responsiveness to volume loading. SVV as a functional preload parameter and for on-line monitoring may help to improve the hemodynamic management.

[Relationship of stress index with lung recruitment and gas exchange in dogs with acute respiratory distress syndrome].

OBJECTIVE: To determine the relationship of stress index with lung recruitment and gas exchange in dogs with acute respiratory distress syndrome (ARDS). METHODS: The ARDS model was induced by infusion of oleic acid intravenously in anesthetized dogs. During volume control ventilation with constant inspiratory flow, the pressure-time (P-t) curve was fitted to a power equation: P = a.time(b)+c, where coefficient b (stress index) describes the shape of the curve: b = 1, straight curve; b < 1, progressive increase in slope; and b > 1, progressive decrease in slope. Tidal volume (V(T)) was 6 ml/kg, and positive end-expiratory pressure (PEEP) was set to obtain a b value between 0.9 and 1.1 before (b = 1) and after (b = 1 after recruiting maneuver) application of a recruiting maneuver (RM). PEEP was changed to obtain 0.6 < b < 0.8 and 1.1 < b < 1.3. Experimental condition sequence was random. Recruited volume (RV) was measured by static pressure-volume curve method. Hemodynamics, pulmonary mechanics and gas exchange were observed at the same time. RESULTS: At b = 1 without RM, the PEEP was (5.0 +/- 3.0) cm H2O, the RV was (27 +/- 15) ml, and the RV increased to (166 +/- 84) ml significantly at b = 1 after RM [PEEP (10.8 +/- 2.3) cm H2O (1 cm H2O = 0.098 kPa), q = 3.18, P < 0.01]. At 1.1 < b < 1.3 after RM, the PEEP was (16.8 +/- 1.1) cm H2O and the RV was (262 +/- 57) ml, which was higher than that at b = 1 after RM (q = 2.54, P = 0.023). At 0.6 < b < 0.8 after RM, the PEEP was (5.6 +/- 2.2) cm H2O and the RV was lower than that at b = 1 after RM (q = 2.85, P = 0.013). The partial pressure of oxygen in arterial blood (PaO2) in b = 1, 0.6 < b < 0.8 and 1.1 < b < 1.3 after RM were (319 +/- 49) mm Hg (1 mm Hg = 0.133 kPa), (246 +/- 57) mm Hg and (314 +/- 27) mm Hg respectively, which was higher than the PaO2 at b = 1 without RM [(153 +/- 64) mm Hg, all q = 2.81, all P < 0.05]. The PaO2 at 0.6 < b < 0.8 was lower than that at b = 1 after RM (q = 2.81, P = 0.005), while there was no significant difference between the PaO2 at 1.1 < b < 1.3 and that at b = 1 after RM. The peak airway pressure and plateau pressure at 1.1 < b < 1.3 were higher than those at b = 1 after RM (q = 6.02, 5.72, all P < 0.05). CONCLUSION: In the b = 1 after RM, there were better PaO2 and lower airway pressure, suggesting that b = 1 after RM may be a good indicator for PEEP titration.

[Comparison of single-indicator thermodilution versus gravimetric measurement in determination of extra-vascular lung water in dogs with acute respiratory distress syndrome].

OBJECTIVE: To compare the measurement of extra-vascular lung water (EVLW) by a single-indicator dilution technique and measurement obtained by gravimetry in different types of acute respiratory distress syndrome (ARDS). METHODS: Thirty-three dogs were randomly assigned to three groups: control group, oleic acid group and hydrochloric acid group. ARDS was reproduced by either intravenous injection of oleic acid or intratracheal instillation of hydrochloric acid. EVLW was measured before ARDS, at the onset of ARDS and 10 hours after ARDS by a single indicator dilution technique. Ten hours after ARDS, dogs were sacrificed and then EVLW was quantitated by a gravimetric measurement (golden standard). Hemodynamics and pulmonary gas exchange were determined. RESULTS: There was a close positive correlation (r=0.8820, P<0.05) between single indicator dilution and gravimetric measurements. However, the measurement with the single indicator dilution was consistently higher than the gravimetric measurement. In the control group, there was a positive correlation (r=0.9870, P<0.05) between the values of EVLW as measured by single indicator dilution and by gravimetric measurements. In the oleic acid group, there was also a significant correlation (r=0.9360, P<0.05) between the values of EVLW as measured by single indicator dilution and by gravimetric measurements. In the hydrochloric acid group, correlation (r=0.7950, P<0.05) was also found between EVLW as measured by the two methods. However, the correlation found was lower in the hydrochloric acid group than those in other two groups. Hydrochloric acid instillation resulted in a significant increase in shunting and the partial pressure of carbon dioxide in artery (PaCO(2)) compared with oleic acid group at 10 hours after ARDS. CONCLUSION: The results of measuring EVLW using single indicator dilution measurement are closely related with those of gravimetric measurement in ARDS, however, the correlations varies with the methods of reproduction of ARDS.

[Effect of protective ventilation and open lung strategy on extravascular lung water in rabbits with acute respiratory distress syndrome].

OBJECTIVE: To study the effect of protective ventilation and open lung strategy on extravascular lung water index (EVLWI) in rabbits with acute respiratory distress syndrome (ARDS). METHODS: Saline-lavaged, anesthetized ARDS rabbits were divided into (1) a moderate tidal volume (V(T)) zero positive end-expiratory pressure (PEEP) group (MVZP group): V(T) 12 ml/kg, PEEP 0 cm H2O; (2) a low V(T) zero PEEP group (LVZP group): V(T) 6 ml/kg, PEEP 0 cm H2O; (3) a low V(T) best PEEP group (LVBP group): V(T) 6 ml/kg, PEEP 10 cm H2O; (4) a low V(T) best PEEP + sustained inflation (SI) group (LVBP + SI group): V(T) 6 ml/kg, PEEP 10 cm H2O + SI. EVLWI was measured by single indicator thermodilution technique at baseline, 0, 1, 2 and 3 h. RESULTS: In the MVZP, LVZP, LVBP, and LVBP + SI groups, EVLWI in the ARDS model [(22.3 +/- 5.6), (20.0 +/- 3.8), (25.7 +/- 9.7), (22.5 +/- 6.2) ml/kg, respectively] was significantly higher than those at baseline [(11.3 +/- 2.4), (10.2 +/- 2.4), (10.3 +/- 4.6), (9.7 +/- 2.3) ml/kg, respectively, all P < 0.05]. In the MVZP group, EVLWI at 2 h and 3 h [(32.0 +/- 12.2), (36.2 +/- 12.4) ml/kg] was higher than that of 0 h [(22.3 +/- 5.6) ml/kg, P < 0.05]. In the LVZP group EVLWI at 2 h and 3 h [(27.8 +/- 12.9), (30.3 +/- 13.0) ml/kg] was also higher than that of 0 h [(20.0 +/- 3.8) ml/kg, P < 0.05]. In the LVBP group, EVLWI at 1 h was (18.5 +/- 8.1) ml/kg and was lower than that of 0 h [(25.7 +/- 9.7) ml/kg, P = 0.027]. In the LVBP + SI group, EVLWI at 1, 2, 3 h [(16.8 +/- 6.5), (18.0 +/- 7.1), (15.7 +/- 2.7) ml/kg] was lower than that of 0 h [(22.5 +/- 6.2) ml/kg, all P < 0.05]. There was significant difference among the four groups at 1 h and 3 h (all P < 0.05). At 1 h and 3 h, compared with MVZP group, EVLWI of the LVBP and the LVBP + SI groups were significantly decreased (all P < 0.05). At 3 h, compared with the EVLWI of the LVZP group, EVLWI of the LVBP + SI group was significantly decreased (P < 0.05). CONCLUSION: Lung protective ventilation and open lung strategy could decrease EVLWI.

[Effect of hydroxyethyl starch and Ringer's solution on splanchnic perfusion in dogs with septic shock].

OBJECTIVE: To investigate the effect of 6% hydroxyethyl starch (HES) and Ringer's solution (RS) on splanchnic perfusion in dogs with septic shock. METHODS: Twenty-four mongrel dogs with septic shock induced by lipopolysaccharides (LPS) were randomly divided into two groups: HES group and RS group. Dogs of each group received an intravenous infusion of HES or RS (1 mlxkg(-1)xmin(-1)) for 60 minutes, followed by normal saline for 180 minutes with same infusion speed. Parameters of hemodynamics, oxygen dynamic, and splanchnic perfusion were monitored at 0, 30, 60, 120, 180, 240 minutes after basic measurements (pre-LPS). RESULTS: (1) After LPS infusion, mean arterial pressure (MAP) and cardiac index (CI) lowered significantly (P<0.05). Compared to that of 0 minutes, MAP and CI were elevated by fluid therapy in both groups, but there was no difference between HES and RS group. (2) Compared with pre-LPS, oxygen delivery (DO(2)) was reduced, arterial blood pH lowered and arterial lactate level increased markedly at 0 minutes (P<0.05). DO(2) increased by fluid therapy in both groups, but DO(2) was higher in HES group at the same time points (P<0.05). Compared to 0 minutes, arterial lactate levels were lowered at 180 minutes in both groups. (3) Mesenteric blood flow decreased after LPS infusion in all animals (P<0.05). Mesenteric blood flow increased after HES infusion, at the same time intramucosal pH (pHi) was elevated and Pg-aCO(2) decreased significantly (all P<0.05), but they showed no difference in RS group. At the same time, mesenteric blood flow and pHi was higher in HES group than that in RS group. CONCLUSION: Both HES and RS could improve MAP and DO(2) in dogs with septic shock, but the effect of HES was better than RS on splanchnic perfusion.