Haemodynamic and respiratory perioperative outcomes for open versus robot-assisted radical cystectomy: A double-blinded, randomised trial.

BACKGROUND: The clinical impact of prolonged steep Trendelenburg position and CO2 pneumoperitoneum during robot-assisted radical cystectomy (RC) on intraoperative conditions and immediate postoperative recovery remains to be assessed. The current study investigates intraoperative and immediate postoperative outcomes for open RC (ORC) versus robot-assisted RC with intracorporal urinary diversion (iRARC) in a blinded randomised trial. We hypothesised that ORC would result in a faster haemodynamic and respiratory post-anaesthesia care unit (PACU) recovery compared to iRARC. METHODS: This study is a predefined sub-analysis of a single-centre, double-blinded, randomised feasibility study. Fifty bladder cancer patients were randomly assigned to ORC (n = 25) or iRARC (n = 25). Patients, PACU staff, and ward personnel were blinded to the surgical technique. Both randomisation arms followed the same anaesthesiologic procedure, fluid treatment plan, and PACU care. The primary outcome was immediate postoperative recovery using a standardised PACU Discharge Criteria (PACU-DC) score. Secondary outcomes included respiration- and arterial O2 saturation scores as well as perioperative interventions and recordings. RESULTS: All patients underwent the allocated treatment. The total PACU-DC score was highest 6 h postoperatively with no difference in the total score between randomisation arms (p = 0.80). Both the ORC and iRARC groups maintained a mean respiration- and arterial O2 saturation score below 1 (out of 3) throughout PACU stay. The iRARC patients had significantly, but clinically acceptable, higher maximum airway pressure and arterial blood pressure, as well as lower minimum pH levels. The ORC group received significantly more opioids after extubation but marginally less analgesics in the PACU, compared to the iRARC group. CONCLUSIONS: A prolonged Trendelenburg position and CO2 pneumoperitoneum was well-tolerated during iRARC, and immediate postoperative recovery was similar for ORC and iRARC patients.

CO2 pneumoperitoneum effects on proliferation and apoptosis in two different neuroblastoma cell lines.

PURPOSE: The proto-oncogene MYCN is considered a transcription factor involved in the regulation of neuroblastoma (NB) cell biology. Since minimally invasive-surgery represents a debated treatment of NB, we investigated CO2 effects on proliferative activity and apoptotic pathway in two NB cell lines, SH-SY5Y (MYCN-non-amplified) and IMR-32 (MYCN-amplified). METHODS: SH-SY5Y and IMR-32 were exposed to CO2 (100%) at a pressure of 15 mmHg for 4 h and then moved to normal condition for 24 h. Cell proliferation, caspase 3 activity and transcript levels of BAX, BCL-2, cyclin B, cyclin D and MMP-2 were evaluated. RESULTS: CO2 exposure caused a decrease in cell proliferation associated to increases in BAX/BCL-2 ratio and caspase 3 activity in SH-SY5Y, while opposite effects have been found in IMR-32. CO2 exposure induced a decrease of cyclin B1 in SH-SY5Y, while an increase in cyclin B1 and D1 was observed in IMR-32. A slight up-regulation of MMP-2 expression in SH-SY5Y and a significant increase of 2.2 folds in IMR-32 was observed (p < 0.05). CONCLUSIONS: Our results suggest that CO2 exposure may cause different effects on various NB cell lines, likely due to MYCN amplification status. Further in vitro and in vivo studies are needed to highlight the role of laparoscopy on NB behaviour.

Proteomic analysis of the influence of CO2 pneumoperitoneum in cervical cancer cells.

OBJECTIVE: The effect of CO2 pneumoperitoneum (CDP) on the oncology outcomes of patients undergoing laparoscopic radical hysterectomy for cervical cancer remains unclear. In this study, we investigated the effects of CDP on the proliferation of cervical cancer cells and examined the molecular mechanism. MATERIALS AND METHODS: We established an in vitro CDP model to study the effects of CDP on the proliferation of cervical cancer cells by Cell Counting Kit-8 (CCK-8) assay, xenografted tumor assay. Tandem mass tag-based quantitative proteomics were used to study the proteomic changes in HeLa cells after CDP treatment. Western blot assay was used to detect the expressions of PI3K/Akt signaling pathway proteins. RESULTS: CDP increased cell proliferation after a short period of inhibition in vitro and promoted tumorigenesis in vivo. Proteomic analysis showed that the expression levels of 177 and 309 proteins were changed significantly 24 and 48 h after CDP treatment, respectively. The acidification caused by CO2 inhibited the proliferation of cervical cancer cells by inhibiting the phosphorylation of PI3K and Akt. CONCLUSIONS: CDP promoted the proliferation of human cervical cancer cells after a short time of inhibition. The mechanism of which is related to the inhibition of phosphorylation of the PI3K/Akt signaling pathway.

Effects of propofol and inhalational anesthetics on the optic nerve sheath diameter in patients undergoing surgery in the steep Trendelenburg position: a systematic review and meta-analysis.

BACKGROUND: Optic nerve sheath diameter (ONSD) is recognized as a surrogate indicator of intracranial pressure (ICP) during surgery. Due to the requirements of surgery, the adjustment to the steep Trendelenburg position and the establishment of CO2 pneumoperitoneum can lead to an increase in ICP, resulting in an increase in the ONSD. Anesthetic agents have different impacts on cerebral blood volume and ICP. The aim of this study was to evaluate the effects of propofol and inhalational anesthetics on the ONSD based on data from randomized controlled trials (RCTs). METHODS: The electronic databases of PubMed, EMBASE, Ovid MEDLINE, the Cochrane Library, and other databases were searched systematically using specified keywords from their inception to June 2021. The Chi-square test and I2 test were used to evaluate the heterogeneity across the studies. The weighted mean difference (WMD) with 95% confidence interval (CI) were adopted to analyze continuous data. RESULTS: A total of 379 patients from 7 studies were involved in this meta-analysis. There were borderline significant differences in the ONSD atT2 between propofol and the control group: T2 (WMD =-0.15, 95% CI: -0.31, -0.00, P=0.005). There were significant differences at T3 (WMD =-0.23,95% CI: -0.42, -0.05, P =0.013) and T4 (WMD  =-0.18, 95% CI: -0.29, -0.07, P =0 .001). After statistical verification, there was no significant difference in the ONSD at T1 between the 2 groups: T1 (WMD =-0.08, 95% CI: -0.26, 0.10, P =0 .368). There were also no significant differences in mean arterial pressure (MAP) (P=0.654, 0.445, 0.698, and 0.562, respectively) and end tidal CO2 (ETCO2) (P=0.081, 0.506, 0.126, and 0.983, respectively) at T1, T2, T3 and T4 between propofol and inhalational anesthetics. DISCUSSION: The findings in the present study indicated that the ONSD during propofol anesthesia was significantly lower than that during inhalational anesthesia after adopting the Trendelenburg position and CO2 pneumoperitoneum. These analysis results suggest that propofol anesthesia may help to minimize changes in ICP compared to inhalational anesthetics.

Pneumoperitoneum induced mesothelial cell changes in a laparoscopic mouse model.

BACKGROUND: CO2 pneumoperitoneum (PP) during laparoscopic surgery, can cause hypoxia and desiccation in the peritoneal mesothelial cell, resulting in a time-dependent retraction and bulging of these cells, an acute inflammatory reaction and enhanced adhesion formation. Since hypoxia is prevented by adding 4% of oxygen (O2) to the CO2 PP, the aim of this study was to evaluate the effect of adding 4% O2 to the CO2 PP on mesothelial cell morphology. METHODS: In a standardized laparoscopic mouse model (n=8 mice per group), a control group with a 30- or 60-min PP with humidified CO2 + 4% of O2 (groups I and II) was compared to a hypoxic group with 30- or 60-min humidified pure CO2 (groups III and IV) and a desiccation group with 60-min of dry CO2 PP (group V). The effect upon the peritoneum morphology was evaluated by scanning electron microscopy (SEM) of abdominal wall peritoneal biopsies. Biopsies, taken immediately (n=4) and 24 hrs (n=4) after surgery, were compared to a group without PP (group VI, n=4). SEM pictures were blindly scored for cell retraction, deletion of microvilli, fibrin deposition, holes in the epithelial layer and visibility of cell borders using a semi-quantitative scoring system. RESULTS: PP Hypoxia (CO2 PP) has a deleterious effect upon mesothelial morphology, immediately (holes: p= 0.04) and 24 hrs later (cell retraction: p=0.005; total score: p=0.03) . Desiccation has also a deleterious effect immediately (microvilli p=0.0090; fibrin deposition p=0.05) and 24 hrs after surgery (cell retraction: p=0.0036; holes: p=0.0004; microvilli: p< 0.0001, fibrin deposition: p=0.0225; borders: p=0.0007). This deleterious effect increases with duration of CO2 PP, affecting cell retraction (p=0.016), holes (p=0.0441), and the total score (p=0.0488). The addition of 4% of O2 to the CO2 PP failed to reach statistical significance. CONCLUSIONS: These data confirm that CO2 PP and dry gas have a deleterious effect on mesothelial cell morphology. Humidification of the insufflation gas reduces this deleterious effect. The hypothesis of a protective effect of adding O2 failed to reach significance.

Effects of sevoflurane and propofol on the optic nerve sheath diameter in patients undergoing laparoscopic gynecological surgery: a randomized controlled clinical studies.

BACKGROUND: The results of studies on changes in intracranial pressure in patients undergoing laparoscopic surgery are inconsistent. Meanwhile, previous neurosurgery studies have suggested that propofol and sevoflurane have inconsistent effects on cerebral blood flow and cerebrovascular self-regulation. The purpose of this study is to compare changes in the optic nerve sheath diameter in patients undergoing laparoscopic gynecological surgery under anesthetic maintenance with propofol versus sevoflurane. METHODS: This study included 110 patients undergoing laparoscopic gynecological surgery with an estimated operative time of more than 2 h under general anesthesia. The study was a randomized controlled study. The optic nerve sheath diameter (ONSD) at various time points was measured by ultrasound, including when the patients entered the operating room (Tawake), after successful anesthesia induction and endotracheal intubation (Tinduction), when the body position was adjusted to the Trendelenburg position and the CO2 pneumoperitoneum pressure reached 14 mmHg, which was recorded as T0. Then, measurements were conducted every 15 min for the first 1 h and then once every hour until the end of the surgery (T15, T30, T45, T1h, T2h …), after the end of surgery and the tracheal tube was removed (Tend), and before the patients were transferred to the ward (Tpacu). RESULTS: A significant difference in optic nerve sheath diameter was found between two groups at T15, T30, T45 (4.64 ± 0.48 mm and 4.50 ± 0.29 mm, respectively, p = 0.031;4.77 ± 0.45 mm and 4.62 ± 0.28 mm, respectively, p = 0.036;4.84 ± 0.46 mm and 4.65 ± 0.30 mm, respectively, p = 0.012), while there was no significant difference at Tawake and other time points. CONCLUSION: During laparoscopic gynecological surgery lasting more than 2 h, the optic nerve sheath diameter was slightly larger in the propofol group than that in the sevoflurane group in the first 45 min. No significant difference was observed between the two groups 1 h after surgery. TRIAL REGISTRATION: clinicaltrials.gov, NCT03498235 . Retrospectively registered 1 March 2018. The manuscript adheres to CONSORT guidelines.

The predictive performance of propofol target-controlled infusion during robotic-assisted laparoscopic prostatectomy with CO2 pneumoperitoneum in the head-down position.

PURPOSE: Propofol clearance can be reduced when cardiac output (CO) is decreased. This clearance reduction may alter the pharmacokinetics of propofol and worsen the predictive performance of target-controlled infusion (TCI) of propofol. The head-down position (HDP) and CO2 pneumoperitoneum, which are required for robotic-assisted laparoscopic prostatectomy (RALP), may cause changes in CO. We investigated the predictive performance of propofol TCI during CO2 pneumoperitoneum in patients who underwent RALP in the HDP. METHODS: Fifteen male patients received propofol TCI using the Diprifusor model. Propofol concentrations were measured at seven time points: (T1) 15 min after anesthesia induction; (T2) before the insufflation; (T3, T4, and T5) 15, 60, and 90 min, respectively, after insufflation in the HDP; (T6) before the release of pneumoperitoneum in the HDP; and (T7) 15 min after the release of pneumoperitoneum in the supine position. Cardiac index (CI) was assessed using an arterial pulse contour CO monitor. The predictive performance of propofol TCI was evaluated by calculating the performance errors (PE) in propofol concentrations for each data point. The relationship between CI and PE was examined. Median PE (MDPE) and median absolute PE (MDAPE) were calculated as measures of bias and accuracy, respectively. RESULTS: A total of 104 blood samples were analyzed. There was significantly negative correlation between CI and PE. The predictive performance of propofol TCI during pneumoperitoneum in the HDP was acceptable (MDPE = - 1.5% and MDAPE = 18.8%). CONCLUSION: The predictive performance of propofol TCI during RALP with CO2 pneumoperitoneum in the HDP was acceptable.

Abdominal wall elasticity of children during pneumoperitoneum.

OBJECTIVE: Laparoscopic surgery in children is often hampered by limited working space. This is partially compensated by stretching the child's abdominal wall. The volume of space that can be gained and changes to abdominal wall elasticity with respect to age are unknown. In the current research, we studied the extent of abdominal wall elasticity while establishing pneumoperitoneum in children. METHODS: One hundred and sixty three children less than 18 years of age, undergoing elective laparoscopic surgery were recruited for the study. After induction of general anesthesia with a standardized muscle relaxant dose, a length of 5 cm was marked above, below and lateral to the umbilicus. The length of the marking was measured under increasing intraabdominal pressure (IAP of 0, 4, 6, 8, 10, 12 mmHg). The measurements were repeated to assess the effect of prestretching. The patients were divided into two groups: infants (less than one year of age) and older children (more than one year of age). RESULTS: Depending on the age and axes of the measurements, a child's abdomen stretches up to 17% on average, with induction of pneumoperitoneum. The percentage of stretch tapers off as the IAP approaches peak pressure. As children become older, the longitudinal abdominal wall elasticity decreases, but the transverse abdominal wall elasticity increases. Regardless of age, prestretching results in a statistically significant increase in the elasticity over the transverse and lower sagittal abdominal wall. CONCLUSION: A child's abdominal wall has considerable expandability. The characteristics of elasticity change depending on the axis and age. Prestretching can improve intraabdominal working space. This knowledge is helpful in port position design for minimally invasive surgery in children. LEVEL OF EVIDENCE: Level II.

Effects of CO2 pneumoperitoneum on proliferation, apoptosis, and migration of gastrointestinal stromal tumor cells.

BACKGROUND: The purpose of the study was to investigate the proliferation and migration capability of human gastrointestinal stromal tumor line GIST-T1 after exposure to different pressures and times of CO2 pneumoperitoneum. METHODS: We established simulated CO2 pneumoperitoneum environment in vitro and divided the human GIST cell GIST-T1 into open control group, 8 mmHg CO2 pneumoperitoneum treatment group and 15 mmHg CO2 pneumoperitoneum treatment group. Each group was divided into two subgroups respectively cultured for 1 h and 3 h. pH value of cell culture, cell growth curve, and cell cycle distribution of each group was measured. By application of scratch healing tests and Transwell chamber experiments, mobility ratio and number of cells through 8 µm membranes were measured to assess the migration ability of cells in each group after intervention. RESULTS: Cell culture pH value of each subgroup in CO2 group decreased significantly after exposed in CO2 pneumoperitoneum (P < 0.01). The proliferation of GIST-T1 cells in 15 mmHg CO2 group was significantly inhibited early (1-2 days) (P < 0.05) and the proliferation of GIST-T1 cells in 8 mmHg CO2 1 h subgroup and 15 mmHg CO2 1 h subgroup was increased significantly late (4-6 days) (P < 0.05) after the interventions of CO2 pneumoperitoneum. The percentage of cells in G0-G1 phase increased, the percentage of S phase cells decreased (P < 0.01) in 1-h subgroup and 3-h subgroup of 15 mmHg CO2 group 24 h after exposure to CO2. The percentage of cells in S phase increased in 1-h subgroup of 8 mmHg CO2 group and decreased in 3-h subgroup of 15 mmHg CO2 group 72 h after exposure to CO2. In the Transwell chamber experiment, the cell number through 8-µm membrane increased significantly (P < 0.01) in 3-h subgroup of CO2 group compared to that in 3-h subgroup of control group. CONCLUSIONS: The routine pressure and duration of CO2 pneumoperitoneum used in clinic did not promote the proliferation of gastrointestinal stromal tumors, but had a potential risk of increasing postoperative recurrence and distant metastasis.

Hydrogen protects against liver injury during CO2 pneumoperitoneum in rats.

The aim of the current study was to identify the protective effect of hydrogen gas against liver injury during CO2 pneumoperitoneum. Rats were randomly divided into three groups: control group (C group), pneumoperitoneum group (P15 group) and hydrogen group (H2 group). Rats in the C group were subjected to anesthesia for 90 min. Rats in the P15 group received an abdominal insufflation of CO2 for 90 min at an intra-abdominal pressure of 15 mmHg. Rats in the H2 group received a hypodermic injection of hydrogen gas (0.2 mL/kg) and after 10 min they received an abdominal insufflation of CO2 for 90 min at an intra-abdominal pressure of 15 mmHg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured to evaluate liver function. Malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) content were measured to evaluate oxidative stress. Nuclear factor E2-related factor 2 (Nrf2) and Nrf2 downstream target genes, apoptosis-related genes and inflammatory cytokine mRNA and protein expression were detected. Liver injury was detected under the microscope. Our results revealed that liver function, antioxidants content, inflammation and liver injury were improved after hydrogen preconditioning in H2 group compared with P15 group. Overall, our results revealed that subcutaneous hydrogen injection could exert a protective effect against liver injury during CO2 pneumoperitoneum through reducing oxidative stress, cell apoptosis and inflammatory cytokines release.

Effects of hypercapnia on postoperative nausea and vomiting after laparoscopic surgery: a double-blind randomized controlled study.

BACKGROUND: Laparoscopic surgery is associated with a high incidence of postoperative nausea and vomiting (PONV). The use of CO2 pneumoperitoneum has been proposed as a potential cause of high PONV incidence. However, intraoperative hypercarbia may be related to enhanced perfusion to the main effector sites for PONV, including the brain and gastrointestinal tract. In this study, we investigated whether an increase in intraoperative CO2 partial pressure in arterial blood (PaCO2) reduces the incidence of PONV. METHODS: This study enrolled 400 female patients aged 20-60 years who were undergoing laparoscopic gynecologic surgery. The patients were allocated randomly to one of three groups with the following intraoperative PaCO2 levels: 36-40 mmHg (Group 1), 41-45 mmHg (Group 2), or 46-50 mmHg (Group 3). The anesthetic regimen used a standardized total intravenous anesthesia consisting of propofol and remifentanil for all patients. The arterial blood gas analysis was performed to identify the difference in CO2 partial pressure between arterial blood and end-tidal gas. The PONV incidence was evaluated for the periods of 0-2, 2-6, and 6-24 h after anesthesia. The incidence and severity of PONV and the administration of rescue antiemetics were recorded. RESULTS: The three groups were comparable for the patient, anesthesia, and surgical characteristics. The average PaCO2 level during surgery was 38-39, 43-44, and 47-48 mmHg in Groups 1, 2, and 3, respectively. The incidence and severity of PONV and use of rescue antiemetics were not significantly different among the groups. The overall incidence of nausea during the first 24-h postoperative period was 54, 48, and 50% in Groups 1, 2, and 3, respectively (P = 0.593). CONCLUSION: Our data suggest that mild to moderate intraoperative hypercapnia did not decrease the incidence and severity of PONV or the requirement for rescue antiemetics after gynecologic laparoscopic surgery.

Effect of CO2 pneumoperitoneum combined with position changes on stability of cardiac electrophysiology in gynecological laparoscopy / 实用医学杂志

Objective To observe the effect of CO2 pneumoperitoneum combined with position changes on the stability of cardiac electrophysiology in gynecological laparoscopy. Methods The gynecological laparoscopy was performed for 30 patients to undergo elective gynecological laparoscopy under general anesthesia ,with the pneumoperitoneum pressure of 12 mmHg and the Trendelenburg positionat 15° . The observations and analyses were done over the basic monitoring index and the QT interval (QT),T peak tend interval (Tp-e),heart rate corrected QT interval(QTc),QT dispersion(QTd),Tp-e/QT before anesthesia(T0),after anesthesia(T1),1 min after pneumoperitoneum (T2),30 min after pneumoperitoneum and head-down tilt (T3),30 min after deflation and supine position(T4). Results Compared with the time point of T0,QTd increased significantly at T1(P<0.05) and so it was with QT,QTc,QTd,Tp-e,Tp-e/QT at T2,T3,and T4(P<0.05). Compared with the time point of T2,QTc,QTd,Tp-e,Tp-e/QT significantly increased at T3(P < 0.05). Conclusions CO2 pneumoperitoneum combined with Trendelenburg position can prolong ventricular repolarization duration and destroy the stability of cardiac electrophysiology so it may increase the incidence of cardiovascular events.

Influence of different CO2 pneumoperitoneum pressure on intestinal mucosal injury and intestinal function recovery in patients undergoing laparoscopic radical gastrectomy / 中国现代普通外科进展

Objective:To evaluate the influence of different CO2 pneumoperitoneum pressure on intestinal mucosal injury and intestinal function recovery in patients undergoing laparoscopic radical gastrectomy.Methods:A total of 120 patients undergoing laparoscopic radical gastrectomy were randomly divided into group A,B and C.Each group included 40 patients.CO2 pneumoperitoneum pressure ingroup A,B and C were 8～10 mmHg,11～13 mmHg and 14～16 mmHg,respectively.The degree of intestinal mucosa damage,plasma D-lactate(2,24 and 48 hours after the treat-ment),intestinal function recovery and complication ration were compared between the three groups.Results:Damage degree of intestinal mucosa after operation in A,B and C groups were 0～1,1～2 and 2～3 respectively.There was significant change in intestinal mucosa injury after operation in both B and C groups.The level of D-lactic acid in group C (2,24 and 48 hours after the treat-ment) were significantly higher those in group A and group B (P＜0.05).The bowel sounds appeared time,exhaust time and intake time in group C were significantly longer than group A and group B (P＜0.05).The incidence of complications were not significantly difference during the three groups.Conclusion:The high pressure of CO2 pneumoperitoneum will cause intestinal mucosa damaged,and not conducive to the patients' intestinal rehabilitation.We suggest that the CO2 pneumoperitoneum pressure should be as low as possible under clear visualization during operation.

Effects of ultrasound-guided stellate ganglion block on autonomic nervous function during CO2-pneumoperitoneum: A randomized double-blind control trial.

BACKGROUND: CO2-pneumoperitoneum can cause sympathetic nerve activity increased and is likely to causes severe stress-related homeostatic disorders. OBJECTIVE: Patients undergoing elective laparoscopic cholecystectomy were administered type-B ultrasound-guided stellate ganglion block (SGB) to observe the effects on autonomic nervous system during CO2- pneumoperitoneum. DESIGN: A randomized, double-blinded, and placebo-controlled study. SETTING: University-affiliated teaching hospital. PATIENTS: Eighty patients (aged 32-75 years; weight, 45-80 kg; American Society of Anesthesiologists (ASA) physical status classification, class I or II) undergoing elective laparoscopic cholecystectomy. INTERVENTIONS: The RSGB group was administered lidocaine 1% 7 ml under ultrasound guidance. MAIN OUTCOME MEASURES: The low frequency (LF), high frequency (HF), total power (TP) and LF/HF ratio were recorded before the block (T0), 5 min (T1) and 30 min (T2) following pneumoperitoneum, 5 min after deflation of pneumoperitoneum (T3) and after surgery (T4). The low-frequency normalized unit (LFnu) and high-frequency normalized units (HFnu) were calculated. RESULTS: Compared with T0, LF, LFnu and LF/HF ratio were significantly elevated at T1-4 (all P< .05 or .01). HFnu was significantly decreased at T2-4 in control group (P< .05) while HF was significantly elevated (P< .01). The LF/HF ratio was significantly decreased (P< .05) at T1-4 in RSGB group. Compared with control group, the LF, LFnu and LF/HF ratio were significantly decreased (P< .05) and HF and HFnu was significantly elevated (P< .05 or .01) at T1-4 in RSGB group. CONCLUSION: Ultrasound-guided RSGB inhibited CO2-pneumoperitoneum-induced sympathetic neural excitation, upregulated vagal nerve stimulation and maintained stable autonomic nervous function.

Effect of different modes of ventilation on PaO2 and PaCO2 in laparoscopic surgery in the Trendelenburg position / 临床麻醉学杂志

Objective To investigate the effects of different ventilation modes on PaCO 2 and PaO 2 during laparoscopic surgery in the Trendelenburg position.Methods Forty cases of laparoscopic resection of rectal cancer were randomly divided into group A (n =20)and group B (n =20).Under general anesthesia,all the cases were in volume-controlled ventilation mode (VCV,tidal volume=10 ml/kg)before pneumoperitoneum.After ventilating in VCV mode for 20 minutes with a lower tidal volume (8 ml/kg),group A was converted to PCV mode for 20 minutes and then back to the VCV mode for 20 minutes again.Next we switched to PCV combined with PEEP (5 cm H 2 O)mode (PCV+PEEP)for 20 minutes.In group B,we only alternated PCV with PCV combined with PEEP.Arte-rial blood-gas analysis was obtained at each time when ventilating mode changed.Results In both group A and B,PaO 2 in VCV mode was less than that in PCV mode and PCV+PEEP mode (P <0.05),PaO 2 in PCV mode was also less than that in mode PCV+PEEP mode (P <0.05).PaCO 2 in PCV and PCV combined with PEEP mode was less than that in VCV mode (P <0.05 ),and there was no difference of PaCO 2 in PCV mode and PCV+PEEP mode.The pH value in VCV mode was less than that in PCV mode and PCV+PEEP mode (P < 0.05).There was no difference in pH value between PCV mode and PCV+PEEP mode.Conclusion PCV combined PEEP mode is beneficial ei-ther in increasing or decreasing of PaCO 2 during laparoscopic surgery in the Trendelenburg position comparing with single VCV mode or PCV mode.

Effect of hyperthermic CO2-treated dendritic cell-derived exosomes on the human gastric cancer AGS cell line.

The aim of the present study was to determine the antitumor effects of hyperthermic CO2 (HT-CO2)-treated dendritic cell (DC)-derived exosomes (Dex) on human gastric cancer AGS cells. Mouse-derived DCs were incubated in HT-CO2 at 43°C for 4 h. The exosomes in the cell culture supernatant were then isolated. Cell proliferation was analyzed using the cell counting kit-8 (CCK-8) assay. Cell apoptosis was observed using flow cytometry, Hoechst 33258 staining and the analysis of caspase-3 activity. In addition, the proliferation of tumor cells was evaluated in xenotransplant nude mice. HT-CO2 markedly inhibited cell proliferation, as assessed by the CCK-8 assay, and also induced apoptosis in a time-dependent manner, as demonstrated by Annexin V/propidium iodide flow cytometry, caspase-3 activity and morphological analysis using Hoechst fluorescent dye. It was also revealed that HT-CO2-treated Dex decreased the expression of heat shock protein 70 and inhibited tumor growth in nude mice. In conclusion, HT-CO2 exerted an efficacious immune-enhancing effect on DCs. These findings may provide a novel strategy for the elimination of free cancer cells during laparoscopic resection. However, the potential cellular mechanisms underlying this process require further investigation.

Montelukast prevents ischaemia/reperfusion-induced ovarian damage in rats.

OBJECTIVE: To investigate the efficacy of montelukast for prevention of ischaemia/reperfusion (I/R) injury in rat ovary. STUDY DESIGN: Twenty-four female adult rats were included in the study. I/R injury was induced by CO2 pneumoperitoneum in a laparoscopic rat model. The rats were divided at random into three groups: the sham group was subjected to catheter insertion but was not subjected to pneumoperitoneum; the saline group was subjected to 60 min of pneumoperitoneum and 30 min of reperfusion, with 1 mg/kg physiological saline administered 10 min before pneumoperitoneum; and the montelukast group was subjected to 60 min of pneumoperitoneum and 30 min of reperfusion, with 20mg/kg montelukast administered 10 min before pneumoperitoneum. Damage to ovarian tissue was scored by histopathological evaluation. Caspase-3 expression was determined immunohistochemically. Ovarian tissue levels of malondialdehyde and glutathione, and plasma total antioxidant capacity were measured biochemically. RESULTS: In comparison with the sham group, ovarian sections in the montelukast group had higher scores for follicular degeneration and oedema (p<0.001). Montelukast treatment prevented tissue damage in ovaries, and this result was significant. Caspase-3 expression was only observed in ovarian surface epithelium in the saline and montelukast groups. However, the mean caspase-3 expression score was higher in the saline group than the montelukast group (p<0.001). Tissue levels of malondialdehyde were higher in the montelukast group than the sham group, but plasma total antioxidant capacity and tissue levels of glutathione were significantly lower. Pretreatment with montelukast reduced lipid peroxidation (p<0.005) and improved antioxidant status in rats (p<0.001). CONCLUSION: Montelukast is effective for the prevention of I/R-induced damage in rat ovary.