One-lung Ventilation Group Research Articles

Role of PI3K-Akt-HIF-1α signaling pathway in dexmedetomidine-induced reduction of damage to unventilated lung during one-lung ventilation in rats

Objective To evaluate the role of PI3K-Akt-HIF-1α signaling pathway in dexmedetomidine-induced reduction of damage to the unventilated lung during one-lung ventilation (OLV) in rats. Methods Forty adult male Sprague-Dawley rats, weighing 250-350 g, were randomly divided into 4 groups (n=10 each) using a random number table: two-lung ventilation (TLV) group, OLV + normal saline group (group OLV), OLV + dexmedetomidine group (group D), and OLV + dexmedetomidine + LY294002 group (group DL). Bilateral lungs were ventilated for 2.5 h in group TLV, and the right lung was ventilated for 2 h followed by 0.5 h TLV in the other groups.The rats were sacrificed, the left lung was removed for determination of wet to dry lung weight ratio (W/D ratio), and expression of phosphorylated Akt (p-Akt) and hypoxia-inducible factor-1 alpha (HIF-1α) (by Western blot). Results Compared with group TLV, W/D ratio was significantly increased, the expression of p-Akt was down-regulated, and the expression of HIF-1α was up-regulated in the other three groups (P<0.05). Compared with group OLV, W/D ratio was significantly decreased, and the expression of p-Akt and HIF-1α was up-regulated in D and DL groups (P<0.05). Compared with group DL, W/D ratio was significantly decreased, and the expression of p-Akt and HIF-1α was up-regulated in group D (P<0.05). Conclusion PI3K-Akt-HIF-1α signaling pathway is involved in dexmedetomidine-induced reduction of damage to the unventilated lung during OLV in rats. Key words: 1-Phosphatidylinositol 3-kinase; Protein-serine-threonine kinases; Hypoxia-indu-cible factor 1, alpha subunit; Dexmedetomidine; Respiration, artificial; Respiratory distress syndrome, adult

Effect of dexmedetomidine pretreatment on expression of caspase-12 in lung tissues undergoing one-lung ventilation in rats

Objective To investigate the effect of dexmedetomidine pretreatment on the expression of caspase-12 in lung tissues undergoing one-lung ventilation(OLV)in rats. Methods Thirty male Sprague-Dawley rats, aged 6–8 weeks, weighing 180–220 g, were randomly allocated into 3 groups(n=10 each)using a random number table: two-lung ventilation(TLV)group, OLV group and dexmedetomidine group(Dex group). Bilateral lungs were ventilated for 2 h in group TLV.In OLV and Dex groups, unilateral lung was ventilated for 1.5 h followed by 0.5 h TLV.In group Dex, dexmedetomidine was infused intravenously at a rate of 3.0 μg·kg–1·h–1 over 60 min starting from 60 min prior to OLV.The equal volume of normal saline was given instead of dexmedetomidine in OLV and TLV groups.Peak airway pressure(Ppeak)and mean airway pressure(Paw)were recorded at 45 min of OLV and 15 min of TLV in OLV and Dex groups, and at 15 min of TLV in group TLV.The rats were then sacrificed, and left lungs were removed for microscopic examination of the pathologic changes(using HE staining)and the ultrastructure of lung tissues(with transmission electron microscope)and for determination of wet to dry lung weight ratio(W/D ratio), cell apoptosis in lung tissues(by TUNEL), caspase-12 mRNA expression(using real-time reverse transcriptase-polymerase chain reaction), and caspase-12 expression(by Western blot). Results Ppeak and Paw were significantly lower at 15 min of TLV than at 45 min of OLV in OLV and Dex groups(P<0.05). Compared to group TLV, W/D ratio and AI were significantly increased, and the expression of caspase-12 protein and mRNA was up-regulated in OLV and Dex groups(P<0.01). Compared to group OLV, W/D ratio and AI were significantly decreased, and the expression of caspase-12 protein and mRNA was down-regulated in group Dex(P<0.01). The pathologic changes of lung tissues were significantly alleviated in group Dex as compared with group OLV. Conclusion The mechanism by which dexmedetomidine pretreatment alleviates acute lung injury caused by OLV is associated with down-regulated expression of caspase-12 and inhibited cell apoptosis in rats. Key words: Dexmedetomidine; Respiration, artificial; Respiratory distress syndrome, adult; Caspase 12

Flurbiprofen axetil increases arterial oxygen partial pressure by decreasing intrapulmonary shunt in patients undergoing one-lung ventilation.

In the present study, we investigated whether flurbiprofen axetil (FA) alleviates hypoxemia during one-lung ventilation (OLV) by reducing the pulmonary shunt/total perfusion (Q s/Q t) ratio, and examined the relationship between the Q s/Q t ratio and the thromboxane B2 (TXB2)/6-keto-prostaglandin F1α (6-K-PGF1α) ratio. Sixty patients undergoing esophageal resection for carcinoma were randomly assigned to groups F and C (n = 30 for each group). FA and placebo were administered i.v. 15 min before skin incision in groups F and C, respectively. The partial pressure of arterial oxygen (PaO2) was measured and the Q s/Q t ratio was calculated. Serum TXB2, 6-K-PGF1α, and endothelin (ET) were measured by radioimmunoassay. The relationship between TXB2/6-K-PGF1α and Q s/Q t was investigated. Compared with group C, PaO2 was higher and the Q s/Q t ratio was lower during OLV in group F (P < 0.05). After treatment with FA, both serum TXB2 and 6-K-PGF1α decreased significantly (P < 0.05) but the TXB2/6-K-PGF1α ratio increased significantly (P < 0.01). Increases in the TXB2/6-K-PGF1α ratio were correlated with reductions in the Q s/Q t ratio during OLV in group F (r = -0.766, P < 0.01). There was no significant difference in serum ET between groups F and C. Treatment with FA reduced the Q s/Q t ratio and further increased the PaO2 level during OLV, possibly due to upregulation of the vasoactive agent TXB2/6-K-PGF1α ratio.

Hydrogen water alleviates lung injury induced by one-lung ventilation

BackgroundWith the development of thoracic surgeries, one-lung ventilation (OLV) has been routinely used to facilitate surgical exposure. However, OLV can cause lung injury during the surgical process and becomes an important factor affecting the outcomes. To date, effective treatments for the prevention of lung injury caused by OLV are lacking. Hydrogen has been demonstrated to have effective protection against tissue injuries caused by oxidative stress, inflammation, and apoptosis. This study investigated the efficacy of hydrogen water consumption on the prevention of lung injury induced by OLV in rats. Materials and MethodsMale Sprague–Dawley rats (n = 32, 240–260 g) were divided randomly into the following four groups: sham group, sham + H2 group, OLV group, OLV + H2 group. The rats drank hydrogen water or degassed hydrogen water for 4 wk before the operation and received OLV for 60 min and two-lung ventilation for 60 min. Lung tissues were assayed for wet-to-dry ratio, oxidative stress variables, proinflammatory cytokines, and hematoxylin–eosin staining. ResultsHydrogen water consumption reduced wet-to-dry weight ratio, malondialdehyde and myeloperoxidase activity and decreased the concentration of TNF-α, IL-1β, and IL-6 in the lung tissues compared with sham group and sham + H2 group. Hydrogen water consumption further attenuated NF-κB activation and caused histopathologic alterations. ConclusionsOur data demonstrated that hydrogen water consumption ameliorated OLV-induced lung injury, and it may exert its protective role by its anti-inflammation, antioxidation and reducing NF-κB activity in the lung tissues.

Effects of dexmedetomidine pretreatment on cell apoptosis induced by endoplasmic reticulum stress and c-Jun N-terminal kinase pathway during one-lung ventilation in rats

Objective To evaluate the effects of dexmedetomidine (DEX) on cell apoptosis induced by endoplasmic reticulum stress and c-Jun N-terminal kinase (JNK) pathway during one-lung ventilation (OLV) in rats. Methods Sixty male Sprague-Dawley rats were randomly allocated into 6 groups (n=10 each): sham operation group (Sham group), OLV group, OLV + atipamezole (α2 receptor antagonist) group (AD group), OLV + atipamezole + DEX group (DEX+ AD group), OLV + low-dose DEX group (DEX-L group) and OLV + high-dose DEX group (DEX-H group). The animals were anesthetized with 10% chloral hydrate 4.5 ml/kg, tracheostomized and mechanically ventilated.Bilateral lungs were ventilated for 2.5 h in Sham group.The right lung was ventilated for 2.0 h followed by 0.5 h two-lung ventilation in OLV group.In DEX-L and DEX-H groups, DEX was infused intravenously for 1 h at a rate of 2.5 μg·kg-1·h-1 and 5.0 μg·kg-1·h-1, respectively, starting from 1 h prior to OLV.Atipamezole 250 μg/kg was injected intravenously at 1 h prior to OLV in AD group.Atipamezole 250 μg/kg was injected intravenously at the onset of DEX infusion (5.0 μg·kg-1·h-1) in DEX+ AD group.The rats were sacrificed and left lungs were removed for determination of weight to dry lung weight ratio (W/D), cell apoptosis in lung tissues (by TUNEL), and expression of glucose-regulated protein 78 (GRP78)mRNA and protein, JNK mRNA and phosphorylated JNK (p-JNK) protein (by RT-PCR and Western blot). Pathological changes of lungs were examined and the injured alveolus rate (IAR) was counted under light microscope.The changes in ultrastructure of lung tissues were observed under transmission electron microscope.Apoptosis index (AI) was calculated. Results W/D, AI and IAR were significantly higher in OLV, AD and DEX+ AD group than in Sham group, while lower in DEX-L and DEX-H groups than in OLV, AD and DEX+ AD groups.The pathological changes of the structure of lung tissues were observed in OLV, AD and DEX+ AD groups, while the pathological changes were significantly alleviated in DEX-L and DEX-H groups.In OLV, AD and DEX+ AD groups, there was apoptosis in lots of pulmonary vascular endothelial cells and alveolar epithelial cells, while cell apoptosis was significantly reduced after administration of DEX.The expression of GRP78 mRNA and protein, JNK mRNA and p-JNK protein was significantly higher in OLV, AD and DEX+ AD groups than in Sham group, and lower in DEX-L and DEX-H groups than in OLV, AD and DEX+ AD groups. Conclusion DEX pretreatment can protect lungs during OLV, and inhibited JNK signaling pathway and reduced cell apoptosis induced by endoplasmic reticulum stress may be involved in the mechanism. Key words: Dexmedetomidine; Respiration, artifical; Endoplasmic reticulum; JNK mitogen-activated protein kinases; Apoptosis

Effect of one-lung ventilation on pulmonary uptake of sevoflurane

Objective To observe the effect of one-lung ventilation (OLV) or two-lung ventilation (TLV) on pulmonary uptake of sevoflurane.Methods Fifteen patients with esophageal tumorectomy and fifteen patients with stomach tumorectomy were selected for OLV and TLV during the operation,respectively.Sevoflurane was used for the general anesthesia.Bispectral index (BIS),Fi and Et were recorded at each measurement point,and Et/Fi was calculated.Results The BIS value of OLV group was higher than that of TLV group (P＜0.05),Et/Fi in OLV group was higher than TLV group (P＜0.01).OLV group:the BIS value gradually decreased and reached into an anesthetic state (BIS:60) at 5 min,and then enough anesthesia depth (BIS:40-60) was maintained during 5 min-120 min.Et gradually increased and reached into a steady state at 30 min.Et/Fi increased and reached into a steady state at 50 min,and the Et/Fi during 50 min-120 min had no statistical significance (P＞0.05).TLV group:the BIS value gradually decreased and reached into an anesthetic state at 2 min,and then enough anesthesia depth was maintained during 2 min-70 min.However,the BIS value was less than 40 after 70 min.Et gradually increased and reached into a steady state at 20 min.Et/Fi gradually increased and reached into a steady state at 2 min,and the Et/Fi during 2 min-120 min had no statistical significance (P＞0.05).Conclusions OLV had an effect on pulmonary uptake of sevoflurane.The total amount of sevoflurane uptake in OLV was less than that in TLV,while the uptake rate of OLV during 2 min-50 min was faster than that of TLV.Both OLV and TLV could supply a surgery-needed anesthetic depth with sevoflurane inhalant concentration 3％vol.However,inhalant concentration should be adjusted after 70 min to avoid excessive anesthesia during TLV.Furthermore,the anesthetic depth of OLV was less than that of TLV,and OLV needed a longer time to reach into a steady state compared with TLV. Key words: One-lung ventilation; Sevoflurane; Pulmonary uptake; Bispectral Index; Et

Effects of curcumin pretreatment on expression of Nrf2 protein during ventilator-induced lung injury in rabbits

Objective To evaluate the effects of curcumin pretreatment on the expression of Nrf2 protein during ventilator-induced lung injury in rabbits.Methods Twenty-four healthy male New Zealand white rabbits,aged 3-6 months,weighing 2.5-3.0 kg,were randomized into 3 groups (n =8 each) using a random number table:two-lung ventilation (TLV) group; one-lung ventilation (OLV) group; and curcumin pretreatment group (group Cur).In group Cur,curcumin 40 mg/kg (dissolved in 2 ml of 1％ sodium carboxymethylcellulose) was given via a gastric tube into the stomach twice a day for 7 consecutive days starting from 7 days before ventilation,while the equal volume of sodium carboxymethylcellulose was given via a gastric tube instead of curcumin in TLV and OLV groups.All the rabbits were tracheostomized,and a tracheal tube was inserted to perform TLV in TLV group,and a tracheal tube was inserted into the right bronchus to establish OLV in OLV and Cur groups.Volumecontrolled ventilation was used in the three groups and the ventilatory parameters were regulated to maintain SpO2 ＞ 90 ％.Immediately before beginning of ventilation (T0) and at 1,2 and 3 h of ventilation (T1-3),arterial blood samples were obtained for blood gas analysis and determination of PaO2.The oxygenation index was calculated.At the end of ventilation,the rabbits were sacrificed and right lungs were removed for determination of wet/dry lung weight ratio (W/D ratio).The right lower lobe was isolated and puhmonary specimens were obtained for determination of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity (using colorimetric method) and the expression of Nrf2 and HO-1 protein (by Western blot) in lung tissues and for microscopic examination of pathological changes of the lung which were scored.Results Compared with group TLV,the W/D ratio,pathological scores,MDA content,and expression of Nrf2 and HO-1 were significantly increased,and the SOD activity and oxygenation index at T2,3 were decreased in OLV and Cur groups (P ＜ 0.05).Compared with group OLV,the W/D ratio,pathological scores,and MDA content were significantly decreased,and the SOD activity,oxygenation index at T3,and expression of Nrf2 and HO-1 were increased in group Cur (P ＜ 0.05).Conclusion Curcumin pretreatment reduces ventilator-induced lung injury through promoting the expression of Nrf2 protein in lung tissues in rabbits. Key words: Curcumin ; Respiration, artificial ; Respiratory distress syndrome, adult ; NF-E2-related factor 2

Changes in expression of aquaporin 1 and aquaporin 4 in lung tissues during one-lung ventilation in patients undergoing pulmonary lobectomy

Objective To evaluate the changes in the expression of aquaporin 1 (AQP1) and aquaporin4 (AQP4) in lung tissues during one-lung ventilation in patients undergoing pulmonary lobectomy.Methods Forty ASA physical status Ⅰ or Ⅱ patients,aged 30-64 yr,weighing 45-79kg,undergoing pulmonary lobectomy,were randomly divided into 2 groups(n=20 each):two-lung ventilation group (group T) and one-lung ventilation group (group O).Anesthesia was induced with iv injection of midazolam,fentanyl,vecuronium and propofol.In group T,the patients were intubated with a single-lumen endotracheal tube and two-lung ventilation was performed.In group O,double-lumen endobranchial tube was inserted,and two-lung ventilation was performed followed by onelung ventilation after chest opening.PET CO2 was maintained at 5.3-24.0 kPa and SpO2 was maintained ＞ 92％.Anesthesia was maintained with iv infusion of remifentanil,propofol and vecuronium.The normal lung tissues were obtained from the site near the pathologic changes for microscopic examination (with light microscope) and examination of the ultrastructure (with transmission electron microscope),and for determination of W/D lung weight ratio,the expression of AQP1 mRNA and AQP4 mRNA (by RT-PCR) and the expression of AQP1 protein and AQP4 protein (by Western blot).Results Compared with group T,W/D lung weight ratio was significantly increased,the expression of AQP1 mRNA and protein was down-regulated in group O (P ＜ 0.05),and no significant changes were found in the expression of AQP4 mRNA and protein in group O (P ＞ 0.05).Pathological changes were observed in group O.Conclusion Down-regulation of AQP1 expression may be involved in the acute lung injury induced by one-lung ventilation in patients undergoing pulmonary lobectomy,however,AQP4 has no such effect. Key words: Aquaporin 1 ; Aquaporin 4; Respiration, artificial

The application of endobronchial blocker in video-assisted thoracoscopy surgery

Objective To evaluate the effects of endobronchial blocker (EBB) in video-assisted thoracoscopy surgery (VATS).Methods 100 patients undergoing VATS were randomly divided into 2 groups (n=50):EBB group (group E) and double-lumen tube (DLT)group (group D).The intubation and positioning time,pulmonary collapse time,the frequence of DLT or bronchial blockage's shifting,effects of one-lung ventilation (OLV),airway pressure and impairments of lower respiratory tract were recorded.Results There were no significant differences in positioning time and effects of OLV between the two groups (P＞0.05).There were significant differences in the time of pulmonary collapse between group E and D,respectively (8.5±3.5) and (4.5±2.9) min,P＜0.05.The frequency of tube cuff shifting in group E was significantly higher than that in group D,respectively 23 and 5(P＜0.05).However,the airway pressure of OLV in group D was higher than group E,respectively(26±4)and (22±3) cm H2O(1 cm H2O=0.098 kPa)(P＜0.05).The number of moderate to severe damage of lower respiratory tract in group D were higher than those in group E,respectively 25 and 12(P＜0.05).Conclusions Compared with DLT,EBB need longer time of pulmonary collapse and its tube cuff is easy to shift.While EBB can be applied in OLV safely and successfully with less impairments of lower respiratory tract.So using of EBB is a good method of OLV in VATS. Key words: Endobronchial blocker; Vedio-assisted thoracoscope; One-lung ventilation

Lung Re-Expansion Following One-Lung Ventilation Induces Neutrophil Cytoskeletal Rearrangements in Rats

To investigate the morphological and functional behavior of neutrophils during and after one-lung ventilation (OLV). We utilized an OLV rat model system and performed 3 hours of OLV followed by either re-expansion (RE) and 30 minutes of two-lung ventilation (TLV) (RE group), only two-lung ventilation (TLV group), or only OLV (OLV group). Cytoskeletal rearrangements of circulating neutrophils were assessed by determining the localization of filamentous actin (F-actin). In addition, the number of sequestered neutrophils in the lung capillary and the cytokine-induced neutrophil chemoattractant 1 (CINC-1) levels in the plasma were determined. The F-actin rimmed neutrophils in the RE group increased after RE, but did not increase in the other groups. In the RE group, the sequestered neutrophils in the ventilated lung were significantly more numerous, and the plasma CINC-1 levels were significantly higher than in the other groups. Lung RE following OLV induces cytoskeletal rearrangements in circulating neutrophils and would thereby promote their sequestration in the lung capillaries. The plasma CINC-1 elevation after RE can be involved in neutrophil recruitment.

Simvastatin attenuates neutrophil recruitment in one-lung ventilation model in rats

To investigate the anti-inflammatory effects of simvastatin in rats undergoing one-lung ventilation (OLV) followed by lung re-expansion. Male Wistar rats (n=30) were submitted to 1-h OLV followed by 1-h lung re-expansion. Treated group received simvastatin (40 mg/kg for 21 days) previous to OLV protocol. Control group received no treatment or surgical/ventilation interventions. Measurements of pulmonary myeloperoxidase (MPO) activity, pulmonary protein extravasation, and serum levels of cytokines and C-reactive protein (CRP) were performed. OLV significantly increased the MPO activity in the collapsed and continuously ventilated lungs (31% and 52% increase, respectively) compared with control (p<0.05). Treatment with simvastatin significantly reduced the MPO activity in the continuously ventilated lung but had no effect on lung edema after OLV. The serum IL-6 and CRP levels were markedly higher in OLV group, but simvastatin treatment failed to affect the production of these inflammatory markers. Serum levels of IL-1β, TNF-α and IL-10 remained below the detection limit in all groups. In an experimental one-lung ventilation model pre-operative treatment with simvastatin reduces remote neutrophil infiltration in the continuously ventilated lung. Our findings suggest that simvastatin may be of therapeutic value in OLV-induced pulmonary inflammation deserving clinical investigations.

Effect of one-lung ventilation on occurrence of subcutaneous emphysema in patients undergoing retroperitoneal laparoscopic urologic surgery

Objective To investigate the effect of one-lung ventilation (OLV) on the occurrence of subcutanous emphysema during retroperitoneal laparoscopic urologic surgery (RPLUS).Methods Twenty-seven ASA Ⅰor Ⅱ patients,aged 29-64 yr,with body mass index 19-25 kg/m2,scheduled for elective RPLUS,were randomly divided into 2 groups:two-lung ventilation (TLV) group (group Ⅰ,n =15) and OLV group (group Ⅱ,n =12).In group Ⅰ,the patients were tracheal intubated and TLV was performed.In group Ⅱ,the left-sided double lumen endobronchial tube was inserted and TLV was performed,OLV on the non-operated side was performed starting from 10-15 min before pneumoperitoneum and TLV resumed at the end of pneumoperitoneum.The end-tidal CO2 partial pressure and minute ventilation volume were measured before pneumoperitoneum (T1),at 30 and 60 min of pneumoperitoneum (T2,3),and at 30 min after the end of pneumoperitoneum (T4).The CO2 absorption capacity was calculated.The degree of pneumoderma was assessed and the occurance of pneumoderma was recorded at the end of pneumoperitoneum.Results Compared with group Ⅰ,the CO2 absorption capacity was significantly reduced,and the degree and incidence of pneumoderma were significantly decreased in group Ⅱ (P ＜ 0.05).Conclusion OLV on the non-operated side can reduce the CO2 absorption capacity,decrease the degree of subcutaneous emphysema and reduce the occurrence of subcutanous emphysema during pneumoperitoneum in patients undergoing RPLUS. Key words: Subcutaneous emphysema; Pulmonary ventilation; Retroperitoneal space; Laparoscopes

Effects of edaravone pretreatment on pulmonary inflammatory response during selective lobar blockade in patients undergoing thoracotomy

Objective To investigate the effects of edaravone pretreatment on pulmonary inflammatory response during selective lobar blockade in patients undergoing thoracotomy,Methods Sixty ASA Ⅰ or Ⅱ patients of both sexes,aged 40-64 yr,weighing 50-80 kg,undergoing esophagectomy were randomly divided into 4 groups (n =15 each):the one-lung ventilation group (group OLV),the edaravone pretreatment + one-lung ventilation group (group E + OLV),the Univent tube selective lobar blockade group (group U) and the edaravone pretreatment + Univent tube selective lobar blockade group (group E + U).Padents in groups OLV and U were intubated with the double lumen endobronchial tube and Univent tube,respectively.Edaravone at a dose of 1 mg/kg was infused into patients at 5 min before one-lung ventilation in group E + OLV and before selective lobar blockade in group E + U,respectively.The patients in groups OLV and U received the equal volume of normal saline.The blood samples (5 ml ) were then drawn from the radial artery after anesthesia induction (T0),at 60 min after onelung ventilation (T1),at the end of operation (T2 ) and 120 min after operation (T3) for detecting the plasma concentrations of TNF-α,IL-6 and IL- 10 by enzyme-linked immunosorbent aesay.Results Compared with the group OLV and U,the plasma concentrations of TNF-α and IL-6 decreased at T2 and T3 in group E + OLV and group E + U (P ＜ 0.05).Condusion Edaravone pretreatment can reduce pulmonary inflammatory response during selective lobar blockade in patients undergoing thoracotomy. Key words: Free radical scavengers; Thoracic surgical procedures; Pulmonary ventilation; Inflam

Effect of sevoflurane preconditioning on heme oxygenase-1 expression in lung tissues during one lung ventilation in rats

Objective To investigate the effect of sevoflurane preconditioning on heme oxygenase-1 (HO-1) expression in lung tissues during one lung ventilation (OLV) in rats.Methods Twenty-four male SD rats weighing 220-250 g were randomly divided into 4 groups ( n =6 each):control group (group C) ; two lung ventilation group (group T); OLV group (group O) and sevoflurane preconditioning+ OLV group (group SO).The animals were anesthetized with intraperitoneal pentobarbital sodium 40 mg/kg.In group T,the animals were tracheal intubated and bilateral lungs were ventilated for 1 h (VT 10 ml/kg,RR 60 bpt/min,I∶E 1∶2) and PETCO2 was maintained at 35-50 mm Hg.In groups O and SO,the animals were tracheal intubated and OLV was performed for 1 h (VT 5 ml/kg,RR 80 bpt/min,I:E 1:2) and PETCO2 was maintained at 35-50 mm Hg.In group SO,2.4％sevoflurane was inhaled for 30 min before OLV and then washed out by inhalation of oxygen for 15 min.The left lung tissues were removed in groups C and T,and the bilateral lung tissues were removed in groups.O and SO for microscopic examination and determination of wet/dry lung weight ratio (W/D ratio) and expression of HO-1 (by Western blot).Results Compared with group C,W/D ratio was significantly increased and the expression of HO-1 was up-regulated in left lung tissues in group T and in bilateral lung tissues in groups O and SO ( P ＜0.05).Compared with group T,W/D ratio was significantly increased and the expression of HO-1 was up-regulated in bilateral lung tissues in group O and in right lung tissues in group SO ( P ＜ 0.05).Compared with group O,W/D ratio was significantly decreased,the expression of HO-1 was up-regulated (P ＜ 0.05) and the pathological changes were reduced in bilateral lung tissues in group SO.Conclusion The mechanism by which sevoflurane preconditioning reduces OLV-induced lung injury is related to up-regulation of HO-1 expression. Key words: Anesthetics,inhalation; Ischemic preconditioning; Respiration, artificial; Heme oxygenase-1; Lung

Effects of selective lobar ventilation on intrapulmonary shunt and inflammatory response in patients with pulmonary dysfunction during thoracotomy

Objective To investigate the effects of selective lobar ventilation on intrapulmonary shunt and inflammatory response in patients with pulmonary dysfunction during thoracotomy.Methods Thirty-four ASA Ⅱ or Ⅲ patients,aged 64-79 yr,weighing 50-85 kg,with moderate and severe impaired pulmonary function,scheduled for esophageal cancer radical correction,were randomly divided into 2 groups( n =17 each): one-lung ventilation group (group A) and selective lobar ventilation group (group B).In group A,endobronchial blocker tube was used to obstruct bronchus principalis and practice one-lung ventilation.In group B,endobronchial blocker tube was used to obstruct bronchi lobares and practice selective lobar ventilation.The blood samples were taken from arteria radialis and internal jugular vein for blood gas analysis and determination of the plasma concentrations of TNF-α,IL-6 and IL-8 by ELISA before anesthesia induction(T0 ),at 30 min following two-lung ventilation at lateral position (T1),at 60 min following one-lung ventilation or selective lobar ventilation (T2) and at the end of surgery (T3).Ppeak and Plat.were recordeded at the same time.Results The incidence of hypoxemia was significantly lower in group B (0) than in group A(18％ )( P ＜0.05).Compared with group A,Pplat and Ppeak at T1-3,Qs/Qt at T2,TNF-α,IL-6 and IL-8 concentrations at T2-3 were significantly decreased in group B( P ＜ 0.05 ).Conclusion The selective lobar ventilation can reduce intrapulmonary shunt,inhibit inflammatory response to help lessen mechanical ventilation related lung injury during thoracotomy in patients with pulmonary function. Key words: Respiration, artificial; Pulmonary circulation; Inflammation

Comparison of the PaO2/FiO2 ratio in sternotomy vs. thoracotomy in mitral valve repair

Cardiac surgery through a thoracotomy using one-lung ventilation (OLV) is thought to be associated with worse postoperative pulmonary gas exchange than sternotomy using two-lung ventilation (TLV), but this has not been confirmed yet. We, therefore, compared postoperative pulmonary gas exchange after mitral valve repair between sternotomy (group TLV) and thoracotomy (group OLV). Randomised controlled study. University teaching hospital. Cardiac surgery patients. Sternotomy or thoracotomy was used for mitral valve repair. The ratio of arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) was compared in both groups before induction of anaesthesia (T0) and just before departure from the operating room to the ICU (T1). Fluid administration, transfusion requirements and urine output were checked intraoperatively. Postoperative haemoglobin (Hb), haematocrit (Hct) and creatinine were evaluated. Cardiopulmonary bypass (CPB) time, intubation time and ICU stay were also recorded. The PaO2/FiO2 ratio (mean ± SD) at T1 was significantly lower than at T0 in both groups (326.9 ± 120.1 vs. 431.9 ± 73.7 mmHg in group TLV, P < 0.001; 374.9 ± 130.9 vs. 445.4 ± 73.7 mmHg in group OLV, P = 0.001), but did not differ significantly between the two groups. The doses of inotropes and vaopressors used were not significantly different between the groups. Intraoperative fluid administration, transfusion requirements, urine output and postoperative Hb/Hct and creatinine did not differ significantly between the groups. CPB time, intubation time and ICU stay also did not differ significantly between the groups. Perioperative pulmonary function following OLV via a thoracotomy was not significantly worse than that following TLV via a sternotomy in mitral valve repair. Not registered.

Efficacy of one lung protective ventilation regimen based on quarsi-static pressure-volume curve in patients undergoing thoracic surgery

Objective To evaluate the efficacy of PEEP set according to pressure-volume (P-V) curve for one lung ventilation (OLV) in patients undergoing thoracic surgery.Methods One hundred and twenty ASA Ⅱ or Ⅲ patients of both sexes aged 20-60 yr weighing 40-80 kg undergoing lobectomy under general anesthesia were enrolled in this study.Double lumen tube was inserted.Correct positioning was verified by fiberoptic bronchoscopy.The patients were mechanically ventilated.P-V curve was determined at 3 min of two-lung ventilation (TLV).Lower inflection point (LIP) was measured and the pressure at LIP (PLIP) was recorded.The patients were randomly divided into 5 groups (n ＝ 24 each):control group (group C) and 4 lung protective ventilation regimen groups ( groups P1-4 ).PEEP was set at 0 and VT was set at 10 ml/kg in group C.PEEP was set at 0 and VT was set at 6 ml/kg in group P1.PEEP was set at PLIP- 2 cm H2O and VT was set at 6 ml/kg in group P2.PEEP was set at PLIP and VT was set at 6 ml/kg in group P3.PEEP was set at PLIP + 2 cm H2O and VT was set at 6 ml/kg in group P4.Peak airway pressure (Ppeak),plateau airway pressure (Pplat),airway resistance (Raw) and lung compliance (CL ) were measured and recorded during OLV and TLV after a period of stabilization.Arterial blood samples were taken before induction of anesthesia and at 20 min of TLV and 20 min of OLV for blood gas analysis.Qs/Qt was calculated.Arterial blood samples were collected at the beginning and end of OLV for determination of plasma concentrations of IL-6 and TNF-α(by ELISA).Results Compared with group C,Ppeak and Pplat were significantly increased while Raw was decreased and plasma IL-6 concentration was significantly decreased at the end of OLV in group P4.PaCO2 was significantly higher during TLV and OLV in groups P1-4 than in group C.There was no significant difference in the parameters of respiratory mechanics,blood gases and plasma IL-6 and TNF-α concentrations among groups P1,2.3.Compared with groups P1,2,3,Ppeak and Pplat were significantly increased while plasma IL-6 concentration was decreased at the end of OLV in group P4.Conclusion Mechanical ventilation with VT set at 6ml/kg and PEEP at PLIP + 2 cm H2 O provides best venfilatory efficacy for OLV in terms of oxygenation and inhibition of inflammatory response. Key words: Positive-pressure respiration; Tidal volume

Efficiency of the newly introduced ventilatory mode “pressure controlled ventilation-volume guaranteed” in thoracic surgery with one lung ventilation

BackgroundAnesthesia for thoracic surgery routinely involves one lung ventilation (OLV). Volume controlled ventilation (VCV) was and still the most common method of performing OLV. We assumed that pressure controlled ventilation-volume guaranteed (PCV-VG) is a better ventilation strategy for OLV than VCV as regard the inspiratory pressures, oxygenation parameters and post-operative ventilatory outcome.MethodsForty patients undergoing elective thoracic surgery in the lateral position requiring at least 1 h of OLV were randomly assigned into two groups. Group VCV: VCV was performed throughout the operation. Group PCV-VG: PCV-VG was performed throughout the operation. Blood gas analysis, peak inspiratory pressure (Ppeak), mean inspiratory pressure (Pmean), plateau inspiratory pressure (Pplateau) were measured: (1) During two lung ventilation (TLV1) 30 min after turning the patient to the lateral decubitus prior the beginning of OLV; (2) 30 min after initiation of OLV(OLV); (3) End of surgery: 30 min after reestablishing TLV (TLV2).ResultsThe Ppeak and the Pplateau were significantly lower in PCV-VG compared with VCV in all stages of the study (P value < 0.05). There was significant increase in all pressure values in OLV compared with TLV1 in the two groups (P value < 0.05). There were significant decrease in the mean Pao2 values during OLV and TLV2 compared with TLV1 in the two groups (P value < 0.05). Yet the Pao2 was significantly higher in the PCV-VG group at OLV and TLV2 compared to the OLV and TLV2 in VCV group. Also Pao2 was significantly lower in TLV2 compared with TLV1 in both groups (P value < 0.05).ConclusionIn patients undergoing thoracic surgery with OLV, pressure controlled volume guaranteed mode of ventilation decreases inspiratory pressure parameters and improve arterial oxygenation better than volume controlled ventilation.

Comparison of two protective lung ventilatory regimes on oxygenation during one-lung ventilation: a randomized controlled trial

BackgroundThe efficacy of protective ventilation in acute lung injury has validated its use in the operating room for patients undergoing thoracic surgery with one-lung ventilation (OLV). The purpose of this study was to investigate the effects of two different modes of ventilation using low tidal volumes: pressure controlled ventilation (PCV) vs. volume controlled ventilation (VCV) on oxygenation and airway pressures during OLV.MethodsWe studied 41 patients scheduled for thoracoscopy surgery. After initial two-lung ventilation with VCV patients were randomly assigned to one of two groups. In one group OLV was started with VCV (tidal volume 6 mL/kg, PEEP 5) and after 30 minutes ventilation was switched to PCV (inspiratory pressure to provide a tidal volume of 6 mL/kg, PEEP 5) for the same time period. In the second group, ventilation modes were performed in reverse order. Airway pressures and blood gases were obtained at the end of each ventilatory mode.ResultsPaO2, PaCO2 and alveolar-arterial oxygen difference did not differ between PCV and VCV. Peak airway pressure was significantly lower in PCV compared with VCV (19.9 ± 3.8 cmH2O vs 23.1 ± 4.3 cmH2O; p < 0.001) without any significant differences in mean and plateau pressures.ConclusionsIn patients with good preoperative pulmonary function undergoing thoracoscopy surgery, the use of a protective lung ventilation strategy with VCV or PCV does not affect the oxygenation. PCV was associated with lower peak airway pressures.

Effect of epidural dexmedetomidine on intraoperative awareness and post‐operative pain after one‐lung ventilation

During combined general and regional anaesthesia, it is difficult to use autonomic signs to assess whether wakefulness is suppressed adequately. We compared the effects of a dexmedetomidine-bupivacaine mixture with plain bupivacaine for thoracic epidural anaesthesia on intraoperative awareness and analgesic benefits, when combined with superficial isoflurane anaesthesia (<0.05 maximum alveolar concentration) in patients undergoing thoracic surgery with one-lung ventilation (OLV). Fifty adult male patients were randomly assigned to receive either epidural dexmedetomidine 1 microg/kg with bupivacaine 0.5% (group D) or bupivacaine 0.5% alone (group B) after induction of general anaesthesia. Gasometric, haemodynamic and bispectral index values were recorded. Post-operative verbal rating score for pain and observer's assessment of alertness/sedation scale were determined by a blinded observer. Dexmedetomidine reduced the use of supplementary fentanyl during surgery. Patients in group B consumed more analgesics and had higher pain scores after operation than patients of group D. The level of sedation was similar between the two groups in the ICU. Two patients (8%) in group B reported possible intraoperative awareness. There was a limited decrease in PaO2 at OLV in group D compared with group B (P<0.05). In thoracic surgery with OLV, the use of epidural dexmedetomidine decreases the anaesthetic requirements significantly, prevents awareness during anaesthesia and improves intraoperative oxygenation and post-operative analgesia.