High Intraperitoneal Pressure Research Articles

Factors affecting intraperitoneal pressure (IPP) and its prognostic value in predicting leak risk and gastrointestinal symptoms in adult peritoneal dialysis patients: a systematic review and meta-analysis.

Intraperitoneal pressure measurementoffers therapeutic and prognostic benefits in predicting leak risks and gastrointestinal symptoms in Peritoneal Dialysis (PD) patients. This systematic review aims to evaluate the prognostic utility of intraperitoneal pressure measurements and different estimated intraperitoneal pressure equations in predicting the risk of non-infectious complications in PD patients. Databases including MEDLINE, EMBASE and Cochrane were searched up to July 2023. Randomised and non-randomised trials were included, focusing on End-Stage Kidney Disease (ESKD) patients undergoing PD. Primary outcomes were variables associated with intraperitoneal pressure, while secondary outcomes included PD-related non-infectious complications and gastrointestinal symptoms. Data synthesis combined meta-analysis with narrative synthesis.This review has been registered on PROSPERO (CRD42023475138). Out of 1828 identified studies, 12 were included for systematic review and 10 for meta-analysis. Body Mass Index (BMI) and Body Surface Area (BSA) showed a consistent positive correlation with intraperitoneal pressure (BMI: r = 0.49, 95% CI 0.35-0.61, I2 = 67.39%, p = 0.003; BSA: r = 0.2, 95% CI 0.08-0.31, I2 = 14.10%, p = 0.324). Conversely, the association between intraperitoneal pressure and age, intraperitoneal volume, and Charlson Comorbidity Index were less consistent. Subgroup analysis demonstrated an association between higher intraperitoneal pressure in patients with increased BMI and BSA. However, the relationship between intraperitoneal pressure and non-infectious mechanical complications remained inconclusive. This review underscores a significant association between intraperitoneal pressure and anthropometric measures (BMI and BSA). The majority of the studies identified included a small sample and considerable bias. However, the association between intraperitoneal pressure and clinically relevant outcomes was not clear. While increasing body mass index and body surface areas are associated with increasing intraperitoneal pressure, the clinical relevance of measuring intraperitoneal pressure in an adult population remains unclear, particularly given the absence of an association with clinically relevant non-infectious outcomes.

Asymmetric porous composite hydrogel patch for microenvironment-adapted repair of contaminated abdominal wall defects

Effective antibacterial property and long-term mechanical support are essential for the repair of complex abdominal wall defects associated with infection. However, clinically available repair materials often fail to meet these requirements, resulting in high surgical failure rate and complications. In this study, an asymmetric porous composite hydrogel patch (cCS/PVA@BAC) with antibacterial, anti-adhesion, pro-healing, and durable mechanical support properties is designed for the efficient repair of contaminated abdominal wall defects. By stepwise phase-conversion and soaking method, robust and stable polyvinyl alcohol hydrogel (PVAH) is integrated with the biocompatible multicomponent hydrogel made of chitosan and carboxymethyl chitosan (cCS), and benzalkonium chloride (BAC) is loaded to enhance the antibacterial property. The cCS layer of cCS/PVA@BAC has an extracellular matrix-like porous structure, which can promote fibroblasts adhesion and wound healing. In contrast, the PVAH layer on the other side with a smooth and dense structure, which can reduce fibroblasts adhesion and prevent visceral adhesion. In addition, the composite hydrogel patch has good anti-swelling and anti-deformation properties as well as stable mechanical strength, thus can withstand high intraperitoneal pressure in the wet internal microenvironment. The loaded BAC can efficiently kill bacteria and improve the local inflammatory microenvironment. With these advantages, cCS/PVA@BAC can significantly reduce inflammation, promote tissue remodeling, and accelerate the healing of contaminated abdominal wall defects in the rat model. These findings suggest a potential use of multifunctional hydrogel patch as an ideal material for effective repair of contaminated soft tissue defects.

Pressurized intraperitoneal aerosol chemotherapy for recurrent ovarian, fallopian or primary peritoneal cancer with peritoneal carcinomatosis: a narrative review.

For recurrent ovarian, fallopian or primary peritoneal cancer with peritoneal carcinomatosis (PC), it is challenging to resect tumors completely or to get complete remission by intravenous (IV) chemotherapy, and many patients show the resistance to various chemotherapeutic agents for IV chemotherapy ultimately. As an alternative, pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been introduced for treating the disease, which delivers chemotherapeutic agents as an aerosol form while maintaining high intraperitoneal (IP) pressure. Based on preclinical studies, PIPAC showed better penetration depth and distribution of drugs into the peritoneum in comparison to conventional IP chemotherapy. Tumor regression on histology and peritoneal carcinomatosis index (PCI) has also been shown in relevant studies. In addition, most of the PIPAC procedures were completed successfully with acceptable toxicity due to the use of a low dose of chemotherapeutic agents. For considering these advantages of PIPAC, we review the current status of PIPAC for treating recurrent ovarian, fallopian or primary peritoneal cancer through literature review.

Identification of the Factors Associated With Intraperitoneal Pressure in ADPKD Patients Treated With Peritoneal Dialysis

IntroductionPeritoneal dialysis (PD) is reported to be underused in the autosomal dominant polycystic kidney disease (ADPKD) population because doctors fear technical failure caused by reduced abdominal space and high intraperitoneal pressure (IPP).MethodsWe designed a multicenter retrospective study to be carried out in 15 French centers recruiting 60 patients with ADPKD treated with PD to identify factors associated with IPP. Inclusion criteria were start of PD between 2010 and 2017, available tomodensitometry, and IPP measurement in the first year of dialysis. The clinical and radiological data for each patient were reviewed by the same operator. Total kidney volume (TKV), liver volume, and the volume of the abdominal cavity were measured using contouring.ResultsTKV and the volume of the abdominal cavity in women and men were, respectively, 2397 ml versus 3758 ml and 9402 ml versus 12,920 ml. In the univariate analysis, IPP was significantly and positively associated with body surface area (P = 0.0024), body mass index (BMI) (P < 0.0001), the volume of the abdominal cavity (P = 0.0005), and the volume of the dialysate infused in the peritoneal cavity (IPV) (P = 0.0108). In the multivariate analysis, only BMI was still significantly associated with IPP (P = 0.0004)ConclusionsOur results identified BMI as the main factor linked to IPP in patients with ADPKD. Despite a reliable assessment of the volume of their organs we did not find any correlation between liver and kidney volumes and IPP. To our knowledge, this is the first study designed to identify factors associated with IPP in patients with ADPKD on PD.

Clinical relevance of marginal factors on ultrafiltration in peritoneal dialysis.

Ultrafiltration (UF) in peritoneal dialysis (PD) is mainly driven by the osmotic gradient and peritoneal permeability, but other factors-such as intraperitoneal pressure (IPP)-also have an influence. To assess the clinical relevance of these marginal factors, we studied 41 unselected PD patients undergoing two consecutive 2 h, 2.27% glucose exchanges, first with 2.5 L and then with 1.5 L. IPP, higher in the 2.5 L exchange, had a wide interpatient range, was higher in obese and polycystic patients and their increase with infusion volume was higher for women regardless of body size. UF with 2.5 L correlated inversely with IPP and was higher for patients with polycystosis or hernias, while for 1.5 L we found no significant correlations. The effluent had higher glucose and osmolarity in the 2.5 L exchange than in the 1.5 L one, similar for both sexes. In spite of this stronger osmotic gradient, only 21 patients had more UF in the 2.5 L exchange, with differences up to 240 mL. The other 20 patients had more UF in the 1.5 L exchange, with stronger differences (up to 800 mL, and more than 240 mL for 9 patients). The second group, with similar effluent osmolarity and peritoneal equilibration test (PET) parameters than the first, has higher IPP and preponderance of men. The sex influence is so intense that men decreased average UF with 2.5 L with respect to 1.5 L, while women increased it. With 2.27% glucose, sex and IPP-modulated by obesity, polycystosis, hernias, and intraperitoneal volume-significantly affect UF in clinical settings and might be useful for its management.

Is Minimally Invasive Surgery Safe in Colorectal Signet Ring Cell Adenocarcinoma?

Background: Signet ring cell adenocarcinoma (SRCC) accounts for around 16% of colorectal cancer patients at our centre. Low E-cadherin expression is seen majority of SRCC. E-cadherin expression downregulation correlates with aggressive biology, invasion and poor prognosis. Studies have shown SRCC to have higher incidence of peritoneal recurrences. High intraperitoneal pressure during minimal access surgery (MIS) might lead to dissemination of tumor cells in SRCC due to poor cell to cell adhesion. We evaluated if patients undergoing MIS had higher recurrence rates and decrease survival as compared to those undergoing open surgery.

Modeling the effect of ascites-induced compression on ovarian cancer multicellular aggregates.

ABSTRACTEpithelial ovarian cancer (EOC) is the most lethal gynecological malignancy. EOC dissemination is predominantly via direct extension of cells and multicellular aggregates (MCAs) into the peritoneal cavity, which adhere to and induce retraction of peritoneal mesothelium and proliferate in the submesothelial matrix to generate metastatic lesions. Metastasis is facilitated by the accumulation of malignant ascites (500 ml to >2 l), resulting in physical discomfort and abdominal distension, and leading to poor prognosis. Although intraperitoneal fluid pressure is normally subatmospheric, an average intraperitoneal pressure of 30 cmH2O (22.1 mmHg) has been reported in women with EOC. In this study, to enable experimental evaluation of the impact of high intraperitoneal pressure on EOC progression, two new in vitro model systems were developed. Initial experiments evaluated EOC MCAs in pressure vessels connected to an Instron to apply short-term compressive force. A Flexcell Compression Plus system was then used to enable longer-term compression of MCAs in custom-designed hydrogel carriers. Results show changes in the expression of genes related to epithelial-mesenchymal transition as well as altered dispersal of compressed MCAs on collagen gels. These new model systems have utility for future analyses of compression-induced mechanotransduction and the resulting impact on cellular responses related to intraperitoneal metastatic dissemination.This article has an associated First Person interview with the first authors of the paper.

A different technique in gasless laparoendoscopic single-site hysterectomy

The aim of this study was to show a different technique for a gasless laparoendoscopic single-site (LESS) hysterectomy and to present advantages and limitations of this technique. Women undergoing gasless LESS hysterectomy with a different technique were evaluated. A total of 14 LESS hysterectomies were performed using this gasless technique and rigid laparoscopic instruments by one surgeon. The mean age of the patients was 48.6 (±4.6). The average blood loss was 80 ± 35 ml. The average time between an umbilical incision and starting hysterectomy was 5 (±2,1) min. The time between starting hysterectomy and umbilical incision closure was 120 (±24) min in the laparoscopic suture group and 88 (±16) min in the vaginal suture group. The mean uterus weight was 188 (±95) g. In conclusion, this different technique is feasible and low cost, especially in non-obese patients. But further studies with large participants are needed to elucidate the safety.Impact statementConventional CO2 pneumoperitoneum has many adverse effects on cardiopulmonary function, haemodynamic, metabolic and neurologic systems due to high-intraperitoneal pressure. The usage of gasless technique eliminates these adverse effects and postoperative shoulder pain. The satisfaction of patients is higher in laparoendoscopic single-site (LESS) hysterectomy due to improved cosmesis and reduced postoperative analgesic requirements.In the literature, there are a few studies showing techniques combining LESS and gasless laparoscopy for hysterectomy. In this study, a different approach for creating operational space in gasless laparoscopy is described. Creation of intraabdominal operational space is convenient and takes a short time in this technique. The average time between an umbilical incision and starting a hysterectomy is five minutes. Additional training is not needed for experienced surgeons in LESS. Also, cost-effectiveness is one of important advantages. It is quite safe, no possibility of vascular injury, including inferior epigastric or superficial epigastric vessels. Also suturing the vaginal cuff and knot tying is easier in this technique.This technique can be used safely in patients with poor cardiopulmonary reserve. Also, by means of its cost effectiveness, it can be preferred in developing countries. As a result, it may be a good alternative to conventional LESS hysterectomy.

Safe Visual Entry at Laparoscopy in Women with Previous Abdominal Surgery Using the Endotip Cannula Though the Lee Huang Point

To assess the safety of the Lee Huang portal using the EndoTIP cannula under high intraperitoneal pressure in women with previous abdominal surgery undergoing laparoscopy.

Principles of safe abdominal entry in laparoscopic gynecologic surgery

Laparoscopic gynecologic surgery has been widely used with a range of benefits. However, there are complications that are related to the abdominal entry process. Serious complications are gastrointestinal tract and major blood vessel injuries. This review introduces the recent available literature to prevent and eliminate the laparoscopic entry complications. The open entry technique is associated with a significant reduction of failed entry, compared to the closed entry technique; however there is no difference in the incidence of visceral or vascular injury. Laparoscopic entry by the left upper abdomen (i.e., Palmer's point) or the middle upper abdomen (i.e., the Lee-Huang point) could be considered in patients with suspected periumbilical adhesions or a history of umbilical hernia, or after three failed attempts of insufflation at the umbilicus. The Lee-Huang point has its own benefit for the operative laparoscopy in large pelvic pathologies and gynecology malignancy cases. The angle of Veress needle insertion varies from 45° in nonobese women to 90° in extraordinarily obese women. The high intra-peritoneal pressure entries, which range from 20 mmHg to 25 mmHg, minimize the risk of vascular injury. Therefore, this will not adversely affect the cardiopulmonary function in healthy women. The Veress intraperitoneal pressure (<10 mmHg) is a reliable indicator of correct intraperitoneal placement of the Veress needle. The elevation of anterior abdominal wall for placement of a Veress needle increases the risks of failed entry and shows no advantage in regard to vascular or visceral complications. Surgeons should continue to increase their knowledge of anatomy, their training, and their experience to decrease laparoscopic complications.

Impact of intraperitoneal pressure of a CO2 pneumoperitoneum on the surgical peritoneal environment†

Animal experiments have suggested that a high intraperitoneal pressure (IPP) might adversely affect the surgical peritoneal environment. The present experimental study investigates the impact of IPP of a CO(2) pneumoperitoneum on human peritoneum. Patients undergoing laparoscopic surgery were subjected to either low (8 mmHg) or standard (12 mmHg) IPP. Normal peritoneum was collected from the parietal wall at the beginning of surgery and every 60 min thereafter. Expression levels of 168 genes that encode extracellular matrix proteins, adhesion molecules or inflammatory cytokine signaling molecules were measured in peritoneal tissues using real-time polymerase chain reaction (PCR)-based assay panels. Human peritoneal mesothelial cells (HPMCs) and human peritoneal fibroblasts (HPFBs) were incubated in a CO(2) insufflation chamber for 1 h at 12 or 8 mmHg. Hyaluronan (HA) synthesis and mRNA expression levels of hyaluronic acid synthases (HAS) and hyaluronidases (Hyal) in HPMCs and HPFBs were measured at 0, 4, 8, 12, 24 and 48 h after CO(2) gas exposure by ELISA and real-time PCR, respectively. Expression levels of connective tissue growth factor (CTGF), matrix metalloproteinase-9, E-selectin, chemokine (C-X-C motif) ligand 2 (CXCL-2), Hyal-1 and Hyal-2 were significantly higher and those of HAS-1, HAS-3, thrombospondin-2 (TSP-2) and interleukin-10 were significantly lower in the 12 mmHg group compared with the 8 mmHg group. HA synthesis was significantly lower in the 12 mmHg group compared with the 8 mmHg group in HPMCs and HPFBs throughout the time course. A low IPP (8 mmHg) may be better than the standard IPP (12 mmHg) to minimize the adverse impact on the surgical peritoneal environment during a CO(2) pneumoperitoneum.

Relationship of arterial and exhaled CO2 during elevated artificial pneumoperitoneum pressure for introduction of the first trocar.

AbstractThe present study evaluated the correlation between arterial CO2 and exhaled CO2 during brief high-pressure pneumoperitoneum. Patients were randomly distributed into two groups: P12 group (n=30) received a maximum intraperitoneal pressure of 12mmHg, and P20 group (n=37) received a maximum intraperitoneal pressure of 20mmHg. Arterial CO2 was evaluated by radial arterial catheter and exhaled CO2 was measured by capnometry at the following time points: before insufflation, once intraperitoneal pressure reached 12mmHg , 5 minutes after intraperitoneal pressure reached 12mmHg for the P12 group or 20mmHg for the P20 group, and 10 minutes after intraperitoneal pressure reached 12mmHg for the P12 group or when intraperitoneal pressure had decreased from 20mmHg to 12mmHg, for the P20 group. During brief durations of very high intraperitoneal pressure (20mmHg), there was a strong correlation between arterial CO2 and exhaled CO2. Capnometry can be effectively used to monitor patients during transient increases in artificial pneumoperitoneum pressure.

Hyaluronan synthesis might be altered after CO2 pneumoperitoneum at a high intraperitoneal pressure

Hyaluronan synthesis might be altered after CO2 pneumoperitoneum at a high intraperitoneal pressure

Impact of intraperitoneal pressure and duration of surgery on levels of tissue plasminogen activator and plasminogen activator inhibitor-1 mRNA in peritoneal tissues during laparoscopic surgery

Our objective was to evaluate the impact of intraperitoneal pressure (IPP) and duration of a CO(2) pneumoperitoneum on the peritoneal fibrinolytic system during laparoscopic surgery. Human study: Patients undergoing laparoscopic surgery were divided into two groups: low (8 mmHg, n= 32) or standard (12 mmHg, n= 36) IPP. Normal peritoneum was collected from the parietal wall at the beginning of surgery and every 60 min thereafter. Mouse study: Mice were divided into three groups: low (2 mmHg) or high (8 mmHg) IPP or laparotomy. Peritoneal tissue was collected at 0, 4, 8, 24, 48 and 72 h, and 5 and 7 days after surgery. Real-time RT-PCR was performed in humans and mice to measure the levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) mRNA in peritoneal tissues. Human study: The tPA/PAI-1 mRNA ratio was significantly decreased in the 12 mmHg group at 1 h [P < 0.0001 versus matched initial peritoneal biopsies (MI)]. The tPA/PAI-1 mRNA ratio decreased in both groups at 2 h (P < .0.01 versus MI). Mouse study: The tPA/PAI-1 ratio was decreased at 0 h, and the difference was significant at 4 h in both the laparotomy (P < 0.001 versus controls, 0 h, 5 and 7 days) and high-IPP (P < 0.0001 versus 0, 48 and 72 h, 5 and 7 days) groups. No changes in tPA/PAI-1 ratio were observed in the low-IPP group. A low IPP and shorter duration of surgery appear to minimally impact the fibrinolytic system during a CO₂ pneumoperitoneum.

Hyaluronan synthesis might be altered during a CO 2 pneumoperitoneum at a high intraperitoneal pressure

OBJECTIVE: Hyaluronan is used in anti adhesive products to prevent postoperative adhesions. The objective of the present study was to investigate whether peritoneal hyaluronan synthase (HAS) mRNA transcription is affected by the intraperitoneal pressure (IPP) and duration of a CO2 pneumoperitoneum.

Laparoscopic Peritoneal Entry with the Reusable Threaded Visual Cannula

Study Objective To estimate the feasibility, reproducibility, and safety of laparoscopic port establishment using a trocarless and externally threaded visual cannula (TVC). Design Multicentre, prospective, observational study (Canadian Task Force classification II-2). Setting Three university-affiliated teaching hospitals. Patients Four thousand seven hundred twenty-four women (median age, 34 years; median body mass index, 25) underwent laparoscopic surgery. Intervention After administration of general anesthesia, the Veress needle was inserted at the umbilicus or the left upper quadrant (LUQ) using Veress intraperitoneal pressure of 10 mm Hg or less as proxy for correct placement. Transient high intraperitoneal pressure of 20 to 30 mm Hg was attained, and primary and ancillary ports were established using the reusable trocarless TVC. Measurements and Main Results Institutional research ethics board approval and patient consent for video capture were obtained. Primary umbilical entry was established in 4598 patients (97.33%), primary LUQ entry in 123 (2.60%), and primary suprapubic entry in 3 (0.06%) patients. Peritoneal preinsufflation was abandoned when 3 consecutive umbilical or LUQ Veress needle insertion attempts failed. Some patients at high risk with known peritoneal adhesions or previous lower abdominal midline scars did not undergo preinsufflation, and the trocarless TVC was applied directly. Surgery was postponed in 3 patients in whom insufflation failed, to enable further counseling and appropriate consenting. There were no serious abdominal wall or intraabdominal vascular injuries. One transverse colon, densely adhered to the umbilical region, was injured, which was recognized and repaired intraoperatively. Residents, fellows, or faculty recorded entry-related data on forms postoperatively for study and analysis. Conclusions Establishing peritoneal ports with the trocarless TVC is feasible, reproducible, and seems to be highly adoptable.

Creation of pneumoperitoneum: noninvasive monitoring of clinical effects of elevated intraperitoneal pressure for the insertion of the first trocar

The aim of this work is to analyze, by means of noninvasive monitoring, the clinical effects of high intraperitoneal pressure for enough time to insert the first trocar. Sixty-seven patients without significant lung problems were randomly divided into groups P12 (n = 30, maximum intraperitoneal pressure 12 mmHg) and P20 (n = 37, maximum intraperitoneal pressure 20 mmHg). A Veress needle was inserted into the left hypochondrium for creation of pneumoperitoneum. The parameters evaluated were heart rate (HR, in bpm), arterial oxygen saturation (SaO(2), expressed as percentage of hemoglobin saturated with oxygen), end-tidal CO(2) (ETCO(2), in mmHg), mean arterial pressure (MAP, in mmHg), and intratracheal pressure (ITP, in cmH(2)O). Clinical parameters were evaluated in both groups at time point 0 (TP0, before CO(2) insufflation), time point 1 (TP1, when intraperitoneal pressure of 12 mmHg was reached in both groups), time point 2 (TP2, 5 min after reaching intraperitoneal pressure of 12 mmHg in group P12 and of 20 mmHg in group P20), and time point 3 (TP3, 10 min after reaching intraperitoneal pressure of 12 mmHg in group P12 and 10 min after TP1 in group P20, when intraperitoneal pressure decreased from 20 to 12 mmHg). Values outside of the normal range or occurrence of atypical phenomena suggestive of organic disease indicated clinical changes. Statistically significant differences were observed between the two groups regarding HR, MAP, ETCO(2), and ITP. No significant clinical changes were observed. Transitory, high intraperitoneal pressure (20 mmHg for 5 min) for insertion of the first trocar resulted in changes in HR, MAP, ETCO(2), and ITP that were within the normal range, and no adverse clinical effects were observed. Therefore, the use of transitory, high intraperitoneal pressure is recommended to prevent iatrogenic injury during blind insertion of the first trocar. Nevertheless, it is not clear that this method would be safe in patients with moderate to severe chronic obstructive pulmonary disease.

Impact of surgical peritoneal environment on postoperative tumor growth and dissemination in a preimplanted tumor model

We recently demonstrated that CO(2) pneumoperitoneum at low intraperitoneal pressure (IPP) had few if any short-term effects on peritoneal dissemination when an ovarian cancer cell line was inoculated just prior to surgery. The objective of the present study was to evaluate the impact of surgical peritoneal environment on postoperative tumor growth and dissemination over time when tumors were present before surgery. On day-7, C57BJ6 mice received an intraperitoneal inoculation of a mouse ovarian cancer cell line (ID8). On day 0, mice were randomized into four groups: anesthesia alone, CO(2) pneumoperitoneum at a low (2 mmHg) or high (8 mmHg) IPP, or laparotomy. Groups were further subdivided into four groups of eight animals each and a laparotomy was performed to evaluate dissemination on postoperative day (POD) 1, 2, 7 or 14. Peritoneal dissemination score was significantly higher in the laparotomy group compared with in the remaining three groups on PODs 2 and 7. We detected no significant differences in the peritoneal dissemination scores among the low-IPP, high-IPP, and anesthesia groups on PODs 2 and 7. However, there were no significant differences in the peritoneal dissemination score among the three surgical groups on POD 14. Histopathological examination demonstrated that the incidence of invasion of cancer cells into the muscle layers was significantly higher in the laparotomy group than in the low-IPP and anesthesia groups on POD 14. There were no significant differences in tumor growth among the four groups. The present findings suggest that CO(2) pneumoperitoneum at either high or low IPP has few if any short-term effects on peritoneal dissemination when tumors are well established before surgery.

Molecular mechanisms underlying postoperative peritoneal tumor dissemination may differ between a laparotomy and carbon dioxide pneumoperitoneum: a syngeneic mouse model with controlled respiratory support

The mechanisms promoting postoperative peritoneal tumor dissemination are unclear. This study aimed to investigate postoperative tumor dissemination over time on both tissue and molecular levels. For this study, C57BL6 mice were randomized into four groups: anesthesia alone (control), carbon dioxide (CO(2)) pneumoperitoneum at low (2 mmHg) or high (8 mmHg) intraperitoneal pressure (IPP), and laparotomy. A mouse ovarian cancer cell line (ID8) was injected intraperitoneally just before surgery. The groups were further subdivided into three groups, and a laparotomy was performed to evaluate tumor dissemination on postoperative day (POD) 7, 14, or 42. The incidence of cancer cell invasion into the muscle layers of the abdominal wall was significantly higher in the laparotomy and high-IPP groups than in the low-IPP and control groups on PODs 7 and 42. Expression levels of beta 1 integrin, cMet, urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), and type-1 plasminogen activator inhibitor (PAI-1) mRNA in the disseminated nodules were not significantly different among the four groups on POD 7. However, the expression levels of all these genes in the disseminated nodules in the laparotomy group were significantly higher on POD 14 than on POD 7. They then returned to control levels on POD 42. There were no significant differences in the expression levels of any of these genes among the groups on POD 42. The current study suggests that the molecular mechanisms underlying postoperative peritoneal tumor dissemination may differ between a laparotomy and CO(2) pneumoperitoneum. Therefore, strategies targeting postoperative tumor dissemination likely will need to account for the surgical environment.

Postoperative Peritoneal Dissemination of Ovarian Cancer Cells is not Promoted by Carbon-dioxide Pneumoperitoneum at Low Intraperitoneal Pressure in a Syngenic Mouse Laparoscopic Model with Controlled Respiratory Support: A Pilot Study

Study Objective To investigate postoperative peritoneal dissemination of ovarian cancer cells in a syngenic mouse model with and without controlled respiratory support (CRS). Design Randomized controlled trial (Canadian Task Force classification I). Setting Academic facility. Subjects Sixty-four female C57BJ6 mice. Interventions Mice were randomly divided into 4 surgical groups: anesthesia alone group; 2 carbon-dioxide pneumoperitoneum groups, 1 with low (2 mm Hg) and 1 with high (8 mm Hg) intraperitoneal pressure (IPP); and finally the laparotomy group. Each of the 4 groups was then subdivided into one group with CRS and the other without. Mouse ovarian cancer cells were injected intraperitoneally just before surgery. Measurements and Main Results A laparotomy was performed to evaluate postoperative peritoneal dissemination of ovarian cancer cells on postoperative day 14. A computerized analysis system was then used to evaluate peritoneal dissemination. In the groups with CRS, the peritoneal dissemination score was significantly higher in the laparotomy and high IPP groups compared with anesthesia alone (p <.0001 vs laparotomy, p <.002 vs high IPP) and low IPP (p <.0002 vs laparotomy, p <.004 vs high IPP) groups. No significant difference was detected between the low IPP and anesthesia alone groups. Conclusion Postoperative peritoneal dissemination of ovarian cancer cells is not promoted by a carbon-dioxide pneumoperitoneum with a low IPP in a mouse model with CRS when assessed on postoperative day 14.