The Effect of CO2 Pressure and Flow Variation on Carbon Particles Spread During Pneumoperitoneum: An Experimental Study.

Background: A correlation between atypical recurrences and minimally-invasive surgery has been suggested in case of urothelial cancer; however, few data are available on the role of pneumoperitoneum in terms of gas flow and intra-abdominal pressure. The objective of the study is to analyze the impact of CO2 pneumoperitoneum variation on an inert material as surrogate of neoplastic cells. Material and Methods: We designed an experimental model mimicking pneumoperitoneum in three settings: sealed flow (no leakage), pulsatile flow (alternating efflux and influx), and continuous flow (AirSeal® insufflator). Each experiment was characterized by a predetermined gas flow and pressure, trocar distance, and position from the particles. Hounsfield density (HD) variation in the areas of interest was measured as index of graphite powder dispersion. A Linear Regression Model was used to measure the correlation between modifiable variables and HD. Results: HD was lower in the pulsatile compared to both the sealed and continuous flows (p < 0.03). On multivariate analysis for sealed setting, flow and total gas liters delivered (i.e., gas leakage) were inversely and independently related to HD (all p < 0.03). In pulsatile setting, trocar position, trocar distance, and gas flow independently predicted HD (all p < 0.03). In continuous setting, gas pressure was directly and independently related to HD (p = 0.004) due to decreased pneumoperitoneum stability and increased CO2 liters delivered. In case of inflow trocar positioned laterally to the particles, low flow (1 L/min), or low pressure (8 mmHg), HD values recorded in the three settings were all overlapping (all p > 0.05). Conclusions: Flow and pressure setting, inflow trocar distance and contiguity from the tumor, and pneumoperitoneum stability may be all crucial components in minimally invasive surgery. In vivo, these variables should be considered as potential risk factors for tumor cells spread within the abdominal cavity. Clinical Trial Registration number: NCT01740011.

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.

Changes of cerebral regional oxygen saturation during pneumoperitoneum and Trendelenburg position under propofol anesthesia: a prospective observational study.

BACKGROUND: We evaluated the change of cerebral regional tissue oxygen saturation (rSO2) along with the pneumoperitoneum and the Trendelenburg position. We also assessed the relationship between the change of rSO2 and the changes of mean arterial blood pressure (MAP), heart rate (HR), arterial carbon dioxide tension (PaCO2), arterial oxygen tension (PaO2), or arterial oxygen saturation (SaO2). METHODS: Forty-one adult patients who underwent a robotic assisted endoscopic prostatic surgery under propofol and remifentanil anesthesia were involved in this study. During the surgery, a pneumoperitoneum was established using carbon dioxide. Measurements of rSO2, MAP, HR, PaCO2, PaO2, and SaO2 were performed before the pneumoperitoneum (baseline), every 5 min after the onset of pneumoperitoneum, before the Trendelenburg position. After the onset of the Trendelenburg position, rSO2, MAP, HR were recorded at 5, 10, 20, 30, 45, and 60 min, and PaCO2, PaO2, and SaO2 were measured at 10, 30, and 60 min. RESULTS: Before the pneumoperitoneum, left and right rSO2 were 67.9 ± 6.3% and 68.5 ± 7.0%. Ten minutes after the onset of pneumoperitoneum, significant increase in the rSO2 was observed (left: 69.6 ± 5.9%, right: 70.6 ± 7.4%). During the Trendelenburg position, the rSO2 increased initially and peaked at 5 min (left: 72.2 ± 6.5%, right: 73.1 ± 7.6%), then decreased. Multiple regression analysis showed that change of rSO2 correlated with MAP and PaCO2. CONCLUSIONS: Pneumoperitoneum and the Trendelenburg position in robotic-assisted endoscopic prostatic surgery did not worsen cerebral oxygenation. Arterial blood pressure is the critical factor in cerebral oxygenation. TRIAL REGISTRATION: Japan Primary Registries Network (JPRN); UMIN-CTR ID; UMIN000026227 (retrospectively registered).

Oxidative damage and mitochondrial injuries differ following pneumoperitoneum pressure in rabbit models of varying degrees of hydronephrosis.

The influence of intraabdominal pressure which is necessary to maintain the operating area during the surgery cannot be ignored especially on the kidneys. Many articles have reported the effect of intraabdominal pressure on normal kidneys. However, the influence of intraabdominal pressure on hydronephrosis kidneys is rarely studied. The aim of the present study was to clarify whether intraabdominal pressure tolerance is modified in various degrees of kidney hydronephrosis by evaluating oxidative damage and mitochondrial injuries. A total of 72 rabbits were randomly divided into three groups (groups N, M and S, which represented rabbits with no, mild and severe hydronephrosis, respectively). Rabbits in groups M (n=24) and S (n=24) underwent a surgical procedure inducing mild or severe hydronephrosis, respectively. Subsequently, rabbits in all groups were allocated to 4 subgroups (N0­N3, M0­M3 and S0­S3) consisting of 6 rabbits each. Groups 0 to 3 were, respectively, subjected to intraabdominal pressures of 0, 5, 10 and 15 mmHg. Oxidative damage was assessed by analyzing levels of reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH­Px), catalase (CAT) and lactate (LD). Mitochondrial injuries were assessed based on mitochondrial membrane potential (MMP) alterations, mitochondrial structure and cytochrome c (cytc) protein expression, as measured by JC­1 staining, electron microscopy and western blotting, respectively. Oxidative damage and mitochondrial injuries were noticeably exacerbated in group N and M with increased levels of ROS, MDA and LD, decreased levels of SOD, GSH­Px, CAT and MMP, mitochondrial vacuolization and higher expression of cytc when the intraabdominal pressure reached 15 mmHg. In group S, these alterations occurred at pressures of 10 and 15 mmHg. Therefore, it was concluded that in rabbits exposed to pneumoperitoneal pressure, kidneys with severe hydronephrosis were more likely to suffer from oxidative damage and mitochondrial injuries compared with kidneys with mild hydronephrosis and normal kidneys.

Porosity and tissue integration of elastic mesh implants evaluated in vitro and in vivo.

PURPOSE: In vivo, a loss of mesh porosity triggers scar tissue formation and restricts functionality. The purpose of this study was to evaluate the properties and configuration changes as mesh deformation and mesh shrinkage of a soft mesh implant compared with a conventional stiff mesh implant in vitro and in a porcine model. MATERIAL AND METHODS: Tensile tests and digital image correlation were used to determine the textile porosity for both mesh types in vitro. A group of three pigs each were treated with magnetic resonance imaging (MRI) visible conventional stiff polyvinylidene fluoride meshes (PVDF) or with soft thermoplastic polyurethane meshes (TPU) (FEG Textiltechnik mbH, Aachen, Germany), respectively. MRI was performed with a pneumoperitoneum at a pressure of 0 and 15 mmHg, which resulted in bulging of the abdomen. The mesh-induced signal voids were semiautomatically segmented and the mesh areas were determined. With the deformations assessed in both mesh types at both pressure conditions, the porosity change of the meshes after 8 weeks of ingrowth was calculated as an indicator of preserved elastic properties. The explanted specimens were examined histologically for the maturity of the scar (collagen I/III ratio). RESULTS: In TPU, the in vitro porosity increased constantly, in PVDF, a loss of porosity was observed under mild stresses. In vivo, the mean mesh areas of TPU were 206.8 cm2 (± 5.7 cm2 ) at 0 mmHg pneumoperitoneum and 274.6 cm2 (± 5.2 cm2 ) at 15 mmHg; for PVDF the mean areas were 205.5 cm2 (± 8.8 cm2 ) and 221.5 cm2 (± 11.8 cm2 ), respectively. The pneumoperitoneum-induced pressure increase resulted in a calculated porosity increase of 8.4% for TPU and of 1.2% for PVDF. The mean collagen I/III ratio was 8.7 (± 0.5) for TPU and 4.7 (± 0.7) for PVDF. CONCLUSION: The elastic properties of TPU mesh implants result in improved tissue integration compared to conventional PVDF meshes, and they adapt more efficiently to the abdominal wall. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 827-833, 2018.

Changes in duration of action of rocuronium following decrease in hepatic blood flow during pneumoperitoneum for laparoscopic gynaecological surgery.

BACKGROUND: A moderate insufflation pressure and deep neuromuscular blockade (NMB) have been recommended in laparoscopic surgery in consideration of the possible reduction in splanchnic perfusion due to the CO2-pneumoperitoneum. Since the liver is the major organ for rocuronium metabolism, the question of whether NMB of rocuronium would change with the variation of liver perfusion during pneumoperitoneum during laparoscopic surgery merits investigation. METHODS: In this prospective study, a total of sixty female patients scheduled for either selective laparoscopic gynaecological surgery (group laparoscopy) or laparotomy for gynaecological surgery (group control) were analyzed. Rocuronium was administered with closed-loop feedback infusion system, which was also applied to monitor NMB complied with good clinical research practice (GCRP). The onset time, clinical duration, and recovery index were measured. Hepatic blood flow was assessed by laparoscopic intraoperative ultrasonography before insufflation/after entering the abdominal cavity (T1), 5 min after insufflation in the Trendelenburg position/5 min after skin incision (T2), 15 min after insufflation in the Trendelenburg position/15 min after skin incision (T3), 30 min after insufflation in the Trendelenburg position/30 min after skin incision (T4), and 5 min after deflation/before closing the abdomen (T5) in group laparoscopy/group control respectively. The relationship between the clinical duration of rocuronium and portal venous blood flow was analyzed using linear or quadratic regression. RESULT: The clinical duration and RI of rocuronium were both prolonged significantly in group laparoscopy (36.8 ± 8.3 min; 12.8 ± 5.5 min) compared to group control (29.0 ± 5.8 min; 9.8 ± 4.0 min) (P < 0.0001; P = 0.018). A significant decrease was found in portal venous blood flow during the entire pneumoperitoneum period in group laparoscopy compared with group control (P < 0.0001). There was a significant correlation between the clinical duration of rocuronium and portal venous blood flow (Y = 51.800-0.043X + (1.86E-005) X 2; r2 = 0.491; P < 0.0001). CONCLUSION: Rocuronium-induced NMB during laparoscopic gynaecological surgery might be prolonged due to the decrease in portal venous blood flow induced by CO2-pneumoperitoneum. Less rocuronium could be required to achieve a desirable NMB in laparoscopic gynaecological surgery. TRIAL REGISTRATION: ChiCTR. Registry number: ChiCTR-OPN-15007524 . Date of registration: December 4, 2015.

Effect of CO2 pneumoperitoneum on the proliferation of human ovarian cancer cell line SKOV-3 and the expression of NM23-H1 and MMP-2.

OBJECTIVE: This study aims to investigate the impacts of CO2 pneumoperitoneum on the growth of ovarian cancer in nude mice and the expression of tumor metastasis suppressor gene (NM23-H1) and matrix metalloproteinase -2 (MMP-2) in SKOV-3 ovarian cancer cell line cancer tissue. METHOD: Forty five nude mice were used to establish ovarian cancer xenograft models by intraperitoneal injection of human ovarian cancer cell line SKOV-3. Murine xenograft models were divided into four groups: control group (only anesthetized for 0.5 h), laparotomy group (laparotomy for 0.5 h), CO2 pneumoperitoneum of 0.5 h, and CO2 pneumoperitoneum of 1 h group. Mice were killed after 12 weeks to observe intraperitoneal tumor growth and detected mRNA expression of NM23-H1 and MMP-2 in tumor tissues by RT-PCR. RESULT: Our data show that xenograft tumors grew faster in the CO2 pneumoperitoneum groups than that in control and laparotomy groups and even faster in the CO2 pneumoperitoneum of 1 h group. The mRNA expression of NM23-H1 in CO2 pneumoperitoneum groups was significantly lower than that in control group and laparotomy group (P < 0.01). Moreover, the longer duration of CO2 pneumoperitoneum negatively correlated with lower expression of NM23-H1 (P < 0.01). In contrast to NM23-H1, MMP-2 expression was significantly higher in CO2 pneumoperitoneum groups than that in the control group and laparotomy group (P < 0.01) and positively correlated with the duration of CO2 pneumoperitoneum (P < 0.01). In addition, there was a negative correlation between the expression of NM23-H1 and MMP-2 (r = -0.984, P < 0.05). CONCLUSION: The CO2 pneumoperitoneum could promote the proliferation and metastasis of human ovarian cancer in nude mice. This effect was positively correlated with the duration of CO2 pneumoperitoneum.

CO(2) pneumoperitoneum induces in vitro hypoxic response culminating in apoptosis of human neuroblastoma cells.

The ablative role of minimally invasive surgery (MIS) in neuroblastoma (NB) is still controversial due to the possible CO2 pneumoperitoneum side-effects on tumor aggressiveness. It is known that CO2 produces hypoxic condition with changes in tumor microenvironment influencing cell functions. Here we investigated whether CO2 exposure affects the transcription factor HIF-1α and the apoptotic signalling pathway in SH-SY5Y NB cells. SH-SY5Y cells were exposed to a pressure of 15 mmHg CO2 (100%) for 4 h (T0) and then moved to normal condition for 24 h (T24). In control and CO2 -exposed cells, we analyzed the mRNA levels and DNA binding activity of HIF-1α. We also evaluated the proliferative activity and cell viability as well as caspase-9/3 cleavage and nuclear fragmentation. A significant increase in HIF- 1α activation was observed in SH-SY5Y cells exposed to CO2 compared to control cells. CO2 treatment also decreased the proliferation rate and the percentage of viable cells. In addition, the expression and cleavage of caspase-9 and -3 were significantly increased in NB cells exposed to CO2. These data correlated with apoptotic feature observed in CO2 -treated NB cells. Our findings show that CO2 -induced hypoxic condition exerts cytotoxic effects on NB cells by eliciting mitochondrial apoptotic pathway and thereby improving the understanding of the possible clinical impact of CO2 pneumoperitoneum on NB behaviour.

P53 related apoptosis in kidneys in CO2 pneumoperitoneum rat model: an immunohistochemical study.

Laparoscopic surgery techniques have been increasingly preferred to classic laparotomy by surgeons since 1987. However, this method may have some side effects on different intraabdominal organs including kidneys. The aim of this study is to evaluate the effects of different pressures of CO2 on p53 related apoptosis in kidneys. Totally 24 male rats were divided into four equal groups. CO2 is insufflated into rats' intraabdominal cavity in two different pressures of 10 and 20 mmHg during 1 h. However, in sham group, only cannula was inserted, but no gas was insufflated. After 1 h, 30 min reperfusion was applied. At last, the kidneys were excised and p53 expression and apoptosis were evaluated immunohistochemically. All the data revealed that the number of apoptotic cell in kidney' tubular cells significantly increases in proportion to CO2 pressure level. On the other hand, p53 expression was detected only in the highest pressure. Because the low CO2 pressured group' rats had no p53 expression in kidneys, we suggest that this method can be safely used for abdominal surgery. At the same time, increasing in the number of apoptotic cells parallel to pressure also suggest that CO2 pressure level and application time are very important parameters during CO2 pneumoperitoneum.

The effect of dexmedetomidine on oxidative stress during pneumoperitoneum.

PURPOSE: This study was intended to investigate the effect of dexmedetomidine on oxidative stress response in pneumoperitoneum established in rats. METHODS: Animals were randomized into three groups, group S: with no pneumoperitoneum, group P: with pneumoperitoneum established, and group D: given 100 mcg intraperitoneal dexmedetomidine 30 min before establishment of pneumoperitoneum. Plasma total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) activity were measured 30 min after conclusion of pneumoperitoneum. RESULTS: The mean TOS level was significantly higher in group P than in the other two groups, and the TOS level was significantly higher in group D than in group S (P < 0.05). Plasma TAS level was found to be lower in group P than in the other two groups, and the TAS level was lower in group D than in group S (P < 0.05). Consequently, the OSI was significantly higher in group P than in groups D and S (P < 0.05). CONCLUSIONS: Ischemia-reperfusion phenomenon that occurs during pneumoperitoneum causes oxidative stress and consumption of plasma antioxidants. Dexmedetomidine decreases oxidative stress caused by pneumoperitoneum and strengthens the antioxidant defense system.

Effect of pneumoperitoneum on renal tissue oxygenation and blood flow in a rat model.

OBJECTIVES: To determine the correlation between the renal blood flow (RBF) and tissue oxygenation (PO(2)) at varying intra-abdominal pressures (IAPs) and to compare the effects on renal blood flow from carbon dioxide-induced pneumoperitoneum. METHODS: Carbon dioxide pneumoperitoneum was established in Sprague-Dawley rats (n = 6). Licox oxygen/temperature tissue probes were laparoscopically inserted into the renal parenchyma, with the renal PO(2) and RBF recorded every 30 seconds while the IAP was gradually increased. Microprobes measuring the RBF, mean arterial pressures and serum pH were placed into the parenchyma to compare the effects of carbon dioxide pneumoperitoneum (n = 7) with that of open surgery (n = 6) and medical air pneumoperitoneum (n = 6). RESULTS: Renal PO(2) was inversely related to the IAP (P < .001). Despite the reduction in IAP, the renal PO(2) in the recovery phase was lower than at baseline (P = .045). The renal PO(2) and RBF changed in a virtually identical pattern at varying levels of IAP (P > .05). The RBF significantly declined with a pneumoperitoneal pressure of 15 and 20 mm Hg (P = .022), regardless of the gas used to create the pneumoperitoneum. A partial reversal of the RBF occurred with a decrease of the IAP. The RBF in the open surgical arm remained unchanged. Although both the serum pH and the mean arterial pressure were inversely proportional to the IAP (P < .001), the mean arterial pressure was depressed to the greatest extent in the medical air group (P = .02). CONCLUSIONS: These results have demonstrated that elevated IAP secondary to pneumoperitoneum causes significant renal hypoxia and decreased RBF. Additionally, this experiment has demonstrated the use of the Licox probes in monitoring the renal PO(2) and established a novel method for evaluating the effects of IAP on the kidney.

The plasminogen activator inhibitor system in colon cancer cell lines is influenced by the CO2 pneumoperitoneum.

PURPOSE: Laparoscopic surgery in the treatment of colon carcinoma causes pH value alterations as well as changes in fibrinolytic activity. This results in enhanced proliferation of colon carcinoma cells in vitro and also in enhanced growth of liver metastasis when compared to isobaric (gasless) laparoscopy in vivo. So far, the direct influence of CO(2) pneumoperitoneum on the invasiveness and metastatic capabilities of colon cancer cells remains unclear. We therefore evaluated transcripts of the uPA system. METHODS: The influence of CO(2) pneumoperitoneum on the gene expression of plasminogen activator inhibitor-1 (PAI-1), urokinase-type plasminogen activator (uPA), and tissue-type plasminogen activator (tPA) was investigated in colon carcinoma cell lines (HT116, SW48, and WiDr) and mesothelial cells employing a pneumoperitoneum chamber in vitro. Quantitative gene expression data were collected using real-time RT-PCR and statistical analysis was performed by means of analysis of variance and Bonferroni correction. RESULTS: The expression of uPA and PAI-1 was increased in colon carcinoma cell lines when cultivated at pH 6.1, a value corresponding to intraabdominal pH values during CO(2) insufflation. Elevated PAI-1 mRNA levels were also observed when CO(2) was simultaneously applied with a pressure of 10 mmHg. In contrast, there were no significant changes in mesothelial cells in the investigated parameter. CONCLUSION: The conditions of CO(2) pneumoperitoneum cause changes in the expression of genes controlling the fibrinolytic activity. The increase of PAI-1 and uPA can contribute to the enhancement of metastasis and invasive potential of tumour cells. Therefore, changes in the conditions of laparoscopy may well optimise laparoscopic therapy in colon cancer.

Carbon dioxide pneumoperitoneum induces anti-inflammatory response and hepatic oxidative stress in young rats with bacterial peritonitis.

PURPOSE: The aim of this study was to investigate the effects of carbon dioxide (CO(2)) pneumoperitoneum on the intra-abdominal spread of bacteria, the local and systemic cytokine expression, and oxidant/antioxidant status in young rats with bacterial peritonitis. METHODS: Young Sprague-Dawley rats, aging 20-27 days and weighing around 50 g, were allocated to six groups of six to nine animals in each. Intra-abdominal infection model was developed by intraperitoneal injection with 1 cc of Escherichia coli (E. coli) (10(8) CFU/mL, ATCC25922 strain) via right lower abdominal wall. Carbon dioxide (CO(2)) pneumoperitoneum was applied to the rats via umbilical pit insufflation with 20 cc CO(2) for 30 min. All survived rats underwent laparotomy and were killed 24 h or 3 days later. Serum levels of CO(2) and CRP were measured. Left lower abdomen peritoneum, peritoneal fluid, mesenteric lymph node of terminal ileum, and liver were taken for bacterial culture. Liver and plasma levels of TNF-α, IL-1ß, and IL-6 were examined for the level of local and systemic immunologic response. Oxidant/antioxidant status in liver and plasma were assessed by measuring malondialdehyde (MDA), and reduced to oxidized glutathione ratio (GSH/GSSG). RESULTS: Carbon dioxide (CO(2)) pneumoperitoneum does not facilitate E. coli dissemination to other intra-abdominal organs in rats with localized E. coli peritonitis. Peritonitis rats that underwent abdominal CO(2) insufflation have insignificantly higher CRP or lower CO(2) levels. Plasma and liver TNF-α, IL-1ß concentrations were not significantly different among the four groups, but plasma IL-6 was significantly increased in rats with E. coli peritonitis and CO(2) pneumoperitoneum that were killed 3 days later as compared with that of rats that were killed 24 h later. In rats with E. coli peritonitis, CO(2) pneumoperitoneum was significantly associated with decreased hepatic GSH/GSSG ratio. However, plasma and liver MDA levels were not altered after CO(2) pneumoperitoneum. CONCLUSIONS: Carbon dioxide (CO(2)) pneumoperitoneum is not associated with E. coli dissemination in the presence of local intra-abdominal infection. CO(2) pneumoperitoneum elicited systemic anti-inflammatory response at a specific time period and decreased hepatic antioxidant status in young rats with E. coli peritonitis.

[Study of CO(2) pneumoperitoneum on the level of vWF in pregnancy rats].

AIM: The goal of this paper is to study changes of von Willebrand Factor in medium and late pregnancy rats' serum during diffencet time and pressure of CO(2) pneumoperitoneum. METHODS: By solid phase phase sandwich enzyme linked immuno sorbent assay (ELISA). RESULTS: (1) We succeed to build the model of carbon dioxide pneumoperitoneum in medium pregnancy rats. (2) The time and pressure of carbon dioxide pneumoperitoneum was proportional to von Willebrand Factor in serum, they have no statistical significance (P>0.05). CONCLUSION: It is safity to operate in medium pregnancy by laparoscopic surgery. But we must control the time in 2 hours.

The effects of carbon dioxide pneumoperitoneum on ovarian blood flow, oxidative stress markers, and morphology during laparoscopy: a rabbit model.

OBJECTIVE: To determine the effect of CO(2) pneumoperitoneum on the ovaries in an experimental pneumoperitoneum model. DESIGN: Experimental controlled study. SETTING: University hospital. PATIENT(S): Sixteen adult female conventional rabbits. INTERVENTION(S): Group I (8 rabbits) was not subjected to intra-abdominal pressure (IAP). In group II (8 rabbits), IAP insufflation was performed at 12 mm Hg. In total, 60 minutes of pneumoperitoneum and 10 minutes of reperfusion were maintained. Ovarian blood flow (OBF) was studied using laser Doppler flowmetry. The time points of OBF measurements were as follows: OBFbaseline, 10 minutes before insufflation; OBF30min, 30 minutes after pneumoperitoneum; OBF60min, 60 minutes after pneumoperitoneum; and OBFreperfusion, 10 minutes after pneumoperitoneum desufflation. Mean OBF changes during CO(2) pneumoperitoneum (OBFmean) were also assessed. MAIN OUTCOME MEASURE(S): Blood perfusion units, tissue malondialdehyde values, and histopathologic damage scores. RESULT(S): In group II, mean OBF values were significantly lower than in group I, especially for OBF30min, OBF60min, OBFreperfusion, and OBFmean. The mean tissue malondialdehyde value for group II was significantly higher than in the control group (104.48 +/- 20.07 nmol/g vs. 64.12 +/- 8.77 nmol/g, respectively). Compared with group I, in group II histologic specimens of the ovaries had higher scores for follicular cell degeneration, vascular congestion, hemorrhage, and inflammatory cell infiltration. CONCLUSION(S): Pneumoperitoneum, even at normal IAP levels, leads to significant oxidative stress-induced biochemical and histologic damage to the ovaries.

[Lipid peroxidation and antiradical defense in patients after endosurgical cholelithiasis].

The peroxide status was studied after cholecystectomy depending on the procedure of a surgical access and the duration of exposure to the pneumoperitoneum during laparoscopic operations. Endosurgical interventions, unlike open operations and miniaccess operations, were found to have the least impact on the values of lipid peroxidation (LPO) expirate. There was evidence that a marked imbalance occurred in the LPO-antioxidant system with longer exposure to the peritoneum.

Effect of small bowel perforation during laparoscopy on end-tidal carbon dioxide: observation in a small animal model.

INTRODUCTION: There are currently no reports in the literature regarding changes in end-tidal carbon dioxide (ETCO(2)) when the small bowel is deliberately or inadvertently perforated during laparoscopic surgery. The aim of this study was to assess the influence of small bowel perforation during laparoscopy on ETCO(2) in a rat model. MATERIALS AND METHODS: Two groups of Wistar rats (n = 8/group) were anesthetized, tracheostomized, and mechanically ventilated at a fixed tidal volume and respiratory rate. After a stabilization phase of 30 min, CO(2) pneumoperitoneum was established to 5 mmHg in one group and 12 mmHg in the other group, and maintained for 30 min. A small bowel perforation was then created and pneumoperitoneum was reestablished for another 30 min. Blood pressure, heart rate, peak ventilatory pressure, and ETCO(2) were recorded throughout the experiment. RESULTS: No significant changes in blood pressure throughout the experiment were noted in either group. The ventilatory pressure increased in both groups after the induction of pneumoperitoneum. In the 5 mmHg group, there was a modest increase in ETCO(2) following the induction of pneumoperitoneum (from 39.4 +/- 1.9 to 41.1 +/- 1.4, P = 0.014), and a further increase following the small bowel perforation (from 41.1 +/- 1.4 to 42 +/- 0.8, P = 0.007). In the 12 mmHg group, there was no change in ETCO(2) after the induction of pneumoperitoneum; however, there was a substantial increase in ETCO(2) following bowel perforation (35.0 +/- 2.0 to 49.8 +/- 7.1, P = 0.002). CONCLUSIONS: ETCO(2) increases when the small bowel is perforated during CO(2) pneumoperitoneum. This increase seems more substantial under higher pneumoperitoneal pressures. Small bowel injury may enable the diffusion of CO(2) through the bowel mucosa, causing ETCO(2) elevation. Therefore, an abrupt increase in ETCO(2) observed during laparoscopy may indicate small bowel injury.

Peritoneal tissue-oxygen tension during a carbon dioxide pneumoperitoneum in a mouse laparoscopic model with controlled respiratory support.

BACKGROUND: Previous animal studies suggested that the peritoneal environment during a carbon dioxide (CO(2)) pneumoperitoneum is hypoxic and that this may contribute to the formation of intra-abdominal adhesions or the growth of malignant cells. There is no study, however, that investigates the relationship between anaesthesia, ventilation and the laparoscopic peritoneal environment to the development of hypoxia. The objective of this study is to monitor the peritoneal tissue-oxygen tension (PitO(2)) under various conditions including anaesthesia alone, during a CO(2) pneumoperitoneum at both low and high intraperitoneal pressure (IPP), and laparotomy, in animal models with controlled respiratory support (CRS). METHODS: C57BL6 mice were divided into eight groups (n = 5) consisting of anaesthesia alone or with CO(2) pneumoperitoneum at low (2 mmHg) or high (8 mmHg) IPP or undergoing laparotomy. Groups were further subdivided into those with or without CRS with endotracheal intubation and mechanical ventilation. Over the course of the 1 h procedure, PitO(2) was continuously monitored. RESULTS: Protocol 1. The PitO(2) levels (104.2 +/- 7.8 mmHg, mean +/- SEM) in non-injured peritoneum during a CO(2) pneumoperitoneum at a low IPP were elevated approximately 2-fold over the levels during laparotomy (49.8 +/- 15.0 mmHg) in ventilated mice. Protocol 2. After insufflation with CO(2), the PitO(2) was immediately elevated and maintained at a higher level. Following laparotomy, it decreased immediately. This elevation was not seen with air insufflation. CONCLUSION: In mice, a significant elevation in PitO(2) occurs during a CO(2) pneumoperitoneum at low IPP with CRS.

Efficiency of tazobactam/piperacillin in lethal peritonitis is enhanced after preconditioning of rats with O3/O2-pneumoperitoneum.

Insufflation of ozonized oxygen into the peritoneum (O3/O2-pneumoperitoneum [O3/O2-PP]) of rats reduced the lethality of peritonitis. We evaluated the prophylactic effect of O3/O2-PP combined with tazobactam/piperacillin (TZP) in polymicrobial lethal peritonitis. Wistar rats were conditioned by daily repeated insufflation of ozone for 5 days, and hematologic parameters were determined. Sepsis was induced by i.p. injection of cecal material derived from donor rats. Simultaneously, TZP was applied at a single dosage of 65 mg/kg or at two dosage schedules of 65 mg/kg each at an interval of 1 h. The conditioning effect of O3/O2-PP on the number of blood cells was measured before inoculation of bacteria. The mRNA levels of proinflammatory cytokine IL-lbeta and TNF-alpha were determined at 4 h post infection in spleen and liver by semiquantitative in situ hybridization analysis. Preconditioning of rats by O3/O2-PP enhanced the number of blood leukocytes and granulocytes and increased the survival rate of septic rats up to 33%. The combination of O3/O2-PP and TZP further enhanced the survival rate up to 93%. This effect was accompanied by a reduced amount of IL-1beta and TNF-alpha mRNA in spleen and liver. In contrast, in non-infected animals the combination of O3/O2-PP and TZP enhanced IL-1beta and TNF-alpha mRNA in the spleen and IL-1beta mRNA in liver when compared with TZP- and sham-treated controls. The preconditioning effect of O3/O2-PP seems to support the biological effectiveness of TZP by altering the immune status before and during the onset of sepsis. The combined therapy could be a simple, preoperative intervention for abdominal surgery to reduce postoperative morbidity and mortality.