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PubMed2001

Morphology of the murine peritoneum after pneumoperitoneum vs laparotomy.

BACKGROUND: Although there have been studies of the effects of pneumoperitoneum on the peritoneal cavity, we still do not know whether the morphologic changes to the peritoneum are different for pneumoperitoneum vs laparotomy. Using scanning electron microscopy, we examined the murine peritoneum after pneumoperitoneum vs laparotomy and compared the changes. METHODS: Forty-five mice were anesthetized with diethyl ether and divided into seven groups. Pneumoperitoneum was established at 5 mmHg for 30 min with carbon dioxide (CO(2)) (n = 9), helium (n = 9), and air (n = 9). One group underwent laparotomy for 30 min (n = 9), and a control group underwent anesthesia only (n = 3). CO(2) pneumoperitoneum was further established at 10 mmHg for 30 min (n = 3) and at 5 mmHg for 60 min (n = 3). After the procedures, the peritoneum was resected from the mesenterium of the small intestine in each animal and examined by scanning electron microscope for morphologic changes of the mesothelial cells. RESULTS: Bulging up of the mesothelial cells was evident immediately after pneumoperitoneum, whereas detachment of the mesothelial cells was present immediately after laparotomy. Bulging up of the mesothelial cells was reduced at 24 h after CO(2) pneumoperitoneum and fully resolved at 72 h in all pneumoperitoneum groups, whereas the mesothelial cells remained detached at 72 h in the laparotomy group. Intercellular clefts were found immediately after helium pneumoperitoneum and were present at 24 h and 72 h after helium pneumoperitoneum, but they were not seen after air pneumoperitoneum and were only evident after CO(2) pneumoperitoneum at 10 mmHg. Depression of the mesothelial cell surface was observed when pneumoperitoneum lasted 60 min. CONCLUSION: Morphologic peritoneal alterations after pneumoperitoneum differed from those after laparotomy and were influenced by the type of gas, amount of pressure, and duration of insufflation. These peritoneal changes after pneumoperitoneum may be associated with a specific intraperitoneal tumor spread after laparoscopic cancer surgery.

Air↗
PubMed1997

[Clinical study of gasless laparoscopic adrenalectomy in 17 cases--comparison between laparoscopic adrenalectomy with and without pneumoperitoneum].

PURPOSE: To determine the efficiency of gasless laparoscopic adrenalectomy, this procedure was compared to that with pneumoperitoneum. PATIENTS AND METHODS: Between February 1994 and December 1996, 17 gasless laparoscopic adrenalectomy were performed in 5 men and 12 women, 36 to 79 years old. Clinical diagnosis was primary aldosteronism in 8, pheocromocytoma in 2, incidentaloma in 4 and adrenal cyst in 3. When gasless laparoscopic adrenalectomy was performed, the laparoscope was inserted through the upper margin of the umbilicus by open laparotomy. To create a workable space, a 1.2 mm Kirschner wire was advanced subcutaneously below the costal arch and attached to a retractor. Operating time, estimated blood loss, changes of the end tidal CO2 concentration during operation, operative complications and postoperative course were compared to those with pneumoperitoneum in 12 cases. RESULTS: In both procedures, satisfying workable spaces were created in all cases. The mean operating time and estimated blood loss were 245 min and 201 ml without pneumoperitoneum, 317 min and 274 ml with pneumoperitoneum, respectively. The mean changes of end tidal CO2 concentration during operation were 3.2 mmHg without pneumoperitoneum and 5.1 mmHg with pneumoperitoneum. As operative complications, open operations were required in 2 cases (1 without pneumoperitoneum and another with pneumoperitoneum) to control intraoperative bleeding. They had the histories of transabdominal operations. Postoperative bleeding was observed in 2 cases (1 without pneumoperitoneum and another with pneumoperitoneum). One of them (with pneumoperitoneum) needed surgical management for hemostasis. Fever over 38 degrees C that occurred in 1 case with pneumoperitoneum appeared to be absorption fever. No differences were observed in the number of the days to the start of oral intake and for postoperative hospitalization between the two groups. CONCLUSIONS: Gasless laparoscopic adrenalectomy is available for most adrenal tumors. Suction could be used unrestrictedly and there were no hemodynamic or ventilatory effects due to pneumoperitoneum. This procedure appears to be safe and advantageous for the treatment of most adrenal tumors.

Adrenal Gland Diseases↗
PubMed2006

Carbon dioxide pneumoperitoneum prevents mortality from sepsis.

BACKGROUND: Carbon dioxide (CO2) pneumoperitoneum has been shown to attenuate the inflammatory response after laparoscopy. This study tested the hypothesis that abdominal insufflation with CO2 improves survival in an animal model of sepsis and investigated the associated mechanism. METHODS: The effect of CO2, helium, and air pneumoperitoneum on mortality was studied by inducing sepsis in 143 rats via intravenous injection of lipopolysaccharide (LPS). To test the protective effect of CO2 in the setting of a laparotomy, an additional 65 animals were subjected to CO2 pneumoperitoneum, helium pneumoperitoneum, or the control condition after laparotomy and intraperitoneal LPS injection. The mechanism of CO2 protection was investigated in another 84 animals. Statistical significance was determined via Kaplan-Meier analysis for survival and analysis of variance (ANOVA) for serum cytokines. RESULTS: Among rats with LPS-induced sepsis, CO2 pneumoperitoneum increased survival to 78%, as compared with using helium pneumoperitoneum (52%; p < 0.05), air pneumoperitoneum (55%; p = 0.09), anesthesia control (50%; p < 0.05), and LPS-only control (42%; p < 0.01). Carbon dioxide insufflation also significantly increased survival over the control condition (85% vs 25%; p < 0.05) among laparotomized septic animals, whereas helium insufflation did not (65% survival). Carbon dioxide insufflation increased plasma interleukin-10 (IL-10) levels by 35% compared with helium pneumoperitoneum (p < 0.05), and by 34% compared with anesthesia control (p < 0.05) 90 min after LPS stimulation. Carbon dioxide pneumoperitoneum resulted in a threefold reduction in tumor necrosis factor-alpha (TNF-alpha) compared with helium pneumoperitoneum (p < 0.05), and a sixfold reduction with anesthesia control (p < 0.001). CONCLUSION: Abdominal insufflation with CO2, but not helium or air, significantly reduces mortality among animals with LPS-induced sepsis. Furthermore, CO2 pneumoperitoneum rescues animals from abdominal sepsis after a laparotomy. Because IL-10 is known to downregulate TNF-alpha, the increase in IL-10 and the decrease in TNF-alpha found among the CO2-insufflated animals in our study provide evidence for a mechanism whereby CO2 pneumoperitoneum reduces mortality via IL-10-mediated downregulation of TNF-alpha.

Abdomen↗
PubMed2000

The effect of carbon dioxide pneumoperitoneum on free radicals.

BACKGROUND: Carbon dioxide is usually preferred as the insufflating agent for laparoscopic surgery because it is readily available, noncombustible, and chemically stable. It is still questionable, however, if CO2 pneumoperitoneum has any effect on free radicals and lipid peroxidation. The purpose of this study was to investigate the possible effects of CO2 pneumoperitoneum on free radicals and lipid peroxidation in the erythrocytes of rats. METHODS: Fifty male Sprague-Dawley rats were divided into five equal groups: controls, a sham-operation group, and three groups of 5, 10, or 15 mmHg pneumoperitoneum with CO2. At the end of the procedure, blood was collected and the erythrocytes were separated from the plasma. The resultant supernatant fractions of erythrocytes were assayed for superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). RESULTS: SOD activities of the 5 and 10 mmHg pneumoperitoneum groups were significantly lower than those of the sham operation group. SOD activity was greater in the 15 mmHg pneumoperitoneum group than in any of the other groups, and this activity was significantly different from that seen in the 5 and 10 mmHg pneumoperitoneum groups (p < 0.05). No significant changes were observed in the CAT activities of the study groups (p > 0.05). MDA level was increased in the 5 mmHg pneumoperitoneum group; this result was statistically different from the control and 15 mmHg pneumoperitoneum groups (p < 0.05). No significant differences were found in the CAT activities for the study groups. On the other hand, the SOD activities of the 5 and 10 mmHg pneumoperitoneum groups were significantly lower than those of the sham and the 15 mmHg pneumoperitoneum group (p < 0.05 for all comparisons). CONCLUSIONS: These results indicate that CO2 pneumoperitoneum applied with 5-10 mmHg pressure increases the formation of free oxygen radicals by inhibiting SOD activity and that the accumulation of free radicals elevates the level of MDA, a metabolite of lipid peroxidation. The effect of CO2 pneumoperitoneum on free radicals and lipid peroxidation is pressure-dependent in rats. The mechanism underlying this pressure dependency is still under investigation.

Animals↗
PubMed1995

Pneumoperitoneum in peritoneal dialysis patients.

There has been recent controversy regarding the clinical significance of pneumoperitoneum in patients undergoing peritoneal dialysis. The incidence of pneumoperitoneum has been estimated to be 21.2% to 33.7% in prior studies of peritoneal dialysis patients. Of the peritoneal dialysis patients with pneumoperitoneum, only a small percentage (5.9% to 14.3%) had documented visceral perforations. The controversy arises in that anywhere from 20% to 100% of peritoneal dialysis patients with pneumoperitoneum and peritonitis had visceral perforation, and 32.4% to 57.1% of chronic ambulatory peritoneal dialysis patients had asymptomatic pneumoperitoneum of unknown etiology. These disparate incidences made clinical interpretation of pneumoperitoneum difficult. In addition, prior study result disagreed as to the usefulness of the extent of pneumoperitoneum in predicting visceral perforation. We retrospectively reviewed 694 chest x-ray film and acute abdominal series reports from 1982 to 1993 in 75 peritoneal dialysis patients, with 9.3 +/- 1.3 (mean +/- SEM) x-ray films per patient. The reports were confirmed by reviewing 363 x-ray films (52%). Eight patients (10.7%) had 10 episodes of pneumoperitoneum. Six of these eight patients had asymptomatic pneumoperitoneum from a known etiology: four had undergone abdominal surgery for catheter placement the prior week and two had catheter manipulation immediately preceding the x-ray. One patient had three episodes of pneumoperitoneum: one after catheter placement and two not associated with a known etiology for pneumoperitoneum while on the cycler. One patient had a surgically confirmed colonic perforation with a large pneumoperitoneum and peritonitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed2003

Pneumoperitoneum versus abdominal wall lift: effects on central haemodynamics and intrathoracic pressure during laparoscopic cholecystectomy.

BACKGROUND: It has been shown repeatedly that laparoscopic cholecystectomy using pneumoperitoneum (CO2 insufflation) may be associated with increased cardiac filling pressures and an increase in blood pressure and systemic vascular resistance. In the present study, the effects on the central circulation during abdominal wall lift (a gasless method of laparoscopic cholecystectomy) were compared with those during pneumoperitoneum. The study was also aimed at elucidating the relationships between the central filling pressures and the intrathoracic pressure. METHODS: Twenty patients (ASA I), scheduled for laparoscopic cholecystectomy, were randomised into two groups, pneumoperitoneum or abdominal wall lift. Measurements were made by arterial and pulmonary arterial catheterization before and during pneumoperitoneum or abdominal wall lift with the patient in the horizontal position. Measurements were repeated after head-up tilting the patients as well as after 30 min head-up tilt. The intrathoracic pressure was monitored in the horizontal position before and during intervention using an intraesophageal balloon. RESULTS: After pneumoperitoneum or abdominal wall lifting there were significant differences between the two groups regarding MAP, SVR, CVP, CI, and SV. Analogous to previous studies, in the pneumoperitoneum group CVP, PCWP, MPAP, and MAP as well as SVR were increased after CO2 insufflation (P < 0.01), while CI and SV were not affected. In contrast, in the abdominal wall lift group, CI and SV were significantly increased (P < 0.01), as was MAP (P < 0.01), while CVP, PCWP, MPAP, and SVR were not significantly affected. There was a significant difference in intraesophageal pressure between the two groups. In the pneumoperitoneum group, the intraesophageal pressure was increased by insufflation (P < 0.01) while, in the abdominal wall lift group, it was unaffected. In the pneumoperitoneum group the mean increases in cardiac filling pressures were of the same magnitude as the mean increase in the intraesophageal pressure. CONCLUSIONS: In healthy patients, abdominal wall lift increased cardiac index while pneumoperitoneum did not. Cardiac filling pressures and systemic vascular resistance were increased by pneumoperitoneum but unaffected by abdominal wall lift. The recorded elevated cardiac filling pressures during pneumoperitoneum may be only a reflection of the increased intra-abdominal pressure.

Abdominal Muscles↗
PubMed1995

Impact of pneumoperitoneum on trocar site implantation of colon cancer in hamster model.

BACKGROUND: Numerous anecdotal reports have documented the spread of colon cancer to trocar sites after laparoscopic-assisted colectomy. We hypothesized that the pneumoperitoneum of laparoscopy potentiated tumor adherence to trocar sites. PURPOSE: This study was designed to determine the effect of CO2 pneumoperitoneum on the rate of tumor implantation at trocar sites. METHODS: Viable GW-39 human colon cancer cells were injected into the abdominal cavity of hamsters (2 x 10(6) cells/hamster). A midline laparotomy, insertion of four 5-mm trocars, injection of viable cells into the mesentery of the cecum, and free peritoneal cavity was performed in two groups: one control group (41) who did not receive a pneumoperitoneum and a comparison group (50) who underwent pneumoperitoneum for ten minutes at an insufflation pressure of 10 mmHg. Animals were killed at six weeks, and hematoxylin and eosin-stained sections of trocar wounds, midline wound, small intestine, cecum, liver, and lung were examined by a veterinary pathologist, who was blinded to operation. RESULTS: Pneumoperitoneum increased tumor implantation in the cecal mesentery and the midline incision (P < 0.05) but did not effect recurrence in the liver, lung, or jejunum. Trocar site implantation tripled with the addition of pneumoperitoneum increased implantation of pneumoperitoneum (26 vs. 75 percent) (P < 0.0001). CONCLUSION: Pneumoperitoneum increased implantation of free intra-abdominal cancer cells at wound sites on the abdominal wall or within the abdominal cavity in this animal model. The use of pneumoperitoneum during laparoscopy in patients with colon cancer should only be performed in a protocol setting to evaluate the effect of pneumoperitoneum on the treatment of cancer.

Animals↗
PubMed2006

Elucidating the relationship between cardiac preload and renal perfusion under pneumoperitoneum.

INTRODUCTION: Pneumoperitoneum is associated with a well-described decrease in renal blood flow, but it remains unclear whether a decrease in cardiac preload is responsible. Our aim was to characterize the relationship between cardiac preload and renal perfusion during pneumoperitoneum. METHODS: Eleven pigs were submitted to three 30 minute study periods: 1) Baseline (n=11): no interventions, 2) Pneumoperitoneum (n=11): 12 mmHg CO2 pneumoperitoneum, 3) Preload Reduction: pneumoperitoneum and nitroglycerin infusion (n=8); or pneumoperitoneum and hemorrhage to a mean arterial pressure (MAP) of 40 mmHg (n=3). Echocardiographic measurements of left ventricular end-diastolic diameter (LVEDD) were used as an index of preload. Renal cortical perfusion (RCP) was measured using laser doppler flowmetry. RESULTS: LVEDD decreased from 4.2 +/- 0.5 to 4.1 +/- 0.6 cm (p=0.02) with pneumoperitoneum and then to 4.0 +/- 0.5 cm (p=0.03) with the addition of nitroglycerin. There was no statistically significant change in RCP with pneumoperitoneum (33.5 +/- 8.4 to 28.5 +/- 8.4 ml/min/100g tissue, p=0.2), but it decreased to 18.5 +/- 11.3 ml/min/100g tissue (p=0.001) with the addition of nitroglycerin. The correlation between RCP and LVEDD was weak (0.35, p=0.003), whereas correlation between RCP and MAP was superior (R=0.59, p<0.0001). CONCLUSIONS: While decreasing preload under extreme lab conditions also decreases RCP, simply creating a pneumoperitoneum of 12 mmHg does not. The decrease in renal blood flow associated with pneumoperitoneum is likely not solely a function of preload.

Animals↗
PubMed2001

Hyaluronic acid secretion during carbon dioxide pneumoperitoneum and its association with port-site metastasis in a murine model.

BACKGROUND: The mechanism of port-site metastasis after laparoscopic cancer surgery is unclear. This study aimed to determine whether carbon dioxide (CO2) pneumoperitoneum caused an increase in hyaluronic acid, which is secreted from mesothelial cells of the peritoneal cavity, and to assess the risk for port-site metastasis using a murine pneumoperitoneal model. METHODS: Sandwich-binding protein assay was used to measure the concentration of hyaluronic acid in the peritoneal cavity at 6, 12, 18, 24, 48, and 72 h after CO2 pneumoperitoneum or laparotomy for 30 min. The concentrations of hyaluronic acid during pneumoperitoneum were compared among different gases (CO2, helium, air), intervals (5, 30, 60 min), and pressures (0-2, 4-6, 8-10 mmHg). To investigate the effects of exogenous hyaluronic acid, the development of port-site metastasis was examined using mouse adenocarcinoma cell-line colon 26 cells. RESULTS: The intraperitoneal concentration of hyaluronic acid after CO2 pneumoperitoneum had increased already at 6 h, had reached the maximum level at 24 h, and had begun to decrease at 72 h. The concentration of hyaluronic acid at 24 h and 48 h in the CO2 pneumoperitoneum group was higher than that in the laparotomy group. This increase in hyaluronic acid also was found during helium and air pneumoperitoneum, and the concentration of hyaluronic acid in the peritoneal cavity was at its maximum when CO2 pneumoperitoneum lasted 30 min at 4 to 6 mmHg. The frequency of port-site metastasis was the highest when hyaluronic acid was injected during CO2 pneumoperitoneum (100%). CONCLUSIONS: In a murine model, the intraperitoneal concentration of hyaluronic acid was significantly increased after CO2 pneumoperitoneum, and the increase was more evident than that after laparotomy. Increased hyaluronic acid during pneumoperitoneum may be associated with port-site metastasis after laparoscopic cancer surgery.

Adenocarcinoma↗
PubMed2005

The addition of O2 to the CO2 does not prevent the systemic effects of the CO2 pneumoperitoneum in a rabbit model.

CO2 pneumoperitoneum used in endoscopic surgery induces systemic effects by CO2 absorption. It was claimed that a reduction in CO2 pneumoperitoneum-induced metabolic hypoxemia was achieved by the addition of small amounts of O2 to the CO2 in a rabbit ventilated model. We reevaluated the effects of the addition of O2 to the CO2 pneumoperitoneum upon CO2 absorption in a rabbit model. The effects of a pneumoperitoneum using 100% CO2, 90% CO2 + 10% O2, 95% CO2 + 5% O2, or 100% O2 on arterial blood gases, acid base and O2 homeostasis were evaluated in nonintubated rabbits. A pneumoperitoneum pressure of 10 cm H2O (approximately 7.35 mm Hg) was used. CO2 pneumoperitoneum of 120 minutes affected blood gases and acid base homeostasis. Whereas partial pressure of CO2 and HCO3 increased (P < 0.001) during pneumoperitoneum, pH and partial pressure of O2 decreased (P < 0.001). Similar results were obtained in O2-CO2 pneumoperitoneum (P > 0.05). CO2 pneumoperitoneum profoundly affected blood gases and acid base homeostasis, resulting in metabolic hypoxemia. The addition of O2 to the CO2 did not prevent the systemic effects of CO2 pneumoperitoneum in nonintubated animals.

Animals↗
PubMed1994

Pneumoperitoneum after laparoscopic cholecystectomy: frequency and duration as seen on upright chest radiographs.

OBJECTIVE: This study aimed to determine the frequency and duration of pneumoperitoneum after laparoscopic cholecystectomy, as detected on upright chest radiographs. MATERIALS AND METHODS: Fifty-five patients who underwent laparoscopic cholecystectomy were studied prospectively. Upright posteroanterior chest radiographs were obtained 6 hr after surgery (day 1); additional radiographs were obtained on days 2, 4, 7, and 14, if required, until the pneumoperitoneum resolved. A perpendicular measurement of any pneumoperitoneum detected between the diaphragm and the liver was obtained. The pneumoperitoneum was graded as absent, trace (1-5 mm), mild (6-10 mm), or moderate (10-15 mm). RESULTS: No evidence of pneumoperitoneum was seen on chest radiographs taken 6 hr after surgery (day 1) in 27 (54%) of the 50 patients who completed the study. Of the remaining 23 patients (46%), all but one showed resolution of the pneumoperitoneum in the first week. Of these 23 patients, 17 showed trace pneumoperitoneum and six showed mild pneumoperitoneum on chest radiographs. CONCLUSION: Despite the use of carbon dioxide gas during laparoscopic cholecystectomy, a significant number of patients have postsurgery pneumoperitoneum that is visible on upright chest radiographs. The pneumoperitoneum resolves in most patients within the first week after surgery.

Carbon Dioxide↗
PubMed2000

Modulation of tumor-induced lethality after pneumoperitoneum in a mouse model.

BACKGROUND: To the authors' knowledge, a generally accepted approach to prevent increased intraabdominal tumor implantation after laparoscopic cancer surgery does not exist. METHODS: One week after establishing an ovarian carcinoma cell line in black mice intraabdominally (n = 156), a carbon dioxide pneumoperitoneum (Group 1: n = 78) was administered. The effect of this procedure on tumor-induced lethality and the therapeutic effect of mitoxantrone and taurolidin mixed with heparin and sodium chloride was investigated. The different drugs were added immediately after the release of the pneumoperitoneum and after 48 hours. The 78 control animals received the drugs at the same time without preexisting pneumoperitoneum. Survival time was registered. RESULTS: The survival time was reduced significantly in all pneumoperitoneum groups compared with the corresponding control group without pneumoperitoneum. The effect of mitoxantrone on survival time (mean, 62.08 days) was diminished significantly by the application of a pneumoperitoneum (mean, 34.27 days). Taurolidine/heparin appeared to have a positive effect on survival time only in the case of a previous pneumoperitoneum (mean of 21.12 days vs. mean of 16.04 days in the pneumoperitoneum control group; P < 0.001). CONCLUSIONS: The induction of a pneumoperitoneum appears to decrease survival time by increasing tumor cell growth and decreases the efficacy of intraperitoneal chemotherapy. The effects of pneumoperitoneum appear to be reduced by the use of heparin/taurolidine, which theoretically blocks extracellular matrix binding domains and inhibits the production of interleukin-1.

Animals↗
PubMed1998

Effects of pneumoperitoneum on tumor implantation with decreasing tumor inoculum.

INTRODUCTION: The aim of this study was to determine the effect of pneumoperitoneum on the rate of trocar-site implantation with decreasing inoculum of cancer cells. METHODS: A total of 0.5 ml of GW-39 human colon cancer cell suspensions at 1 percent (approximately 3.2 x 10(5) cells) and at 0.5 percent (approximately 1.6 x 10(5) cells; v/v) were injected into the abdomen of hamsters through a midline incision. Animals in each group were randomized to receive either pneumoperitoneum (1 percent = 33; 0.5 percent = 43) or not (1 percent = 32; 0.5 percent = 39). Gross and microscopic tumor implants were documented seven weeks later at four trocar sites. RESULTS: In the 1 percent group, pneumoperitoneum significantly increased trocar-site tumor implants from 50 to 71 percent (P < 0.001). Pneumoperitoneum also resulted in the following: 1) more frequent involvement of all four concurrent sites (38 vs. 10 percent; P < 0.02); 2) more frequent palpable tumors (13 vs. 5 percent; P < 0.01); 3) larger tumor mass (2.1 +/- 0.6 g vs. 0.2 +/- 0.1 g; P < 0.02). In the 0.5 percent group, pneumoperitoneum did not significantly increase trocar-site tumor implants, and it did not result in a larger tumor mass. The percent increase in trocar-site implants owing to pneumoperitoneum was influenced by the amount of tumor inoculum (21 percent in the 1 percent group; 10 percent in the 0.5 percent group). The mass of palpable tumor implants after pneumoperitoneum decreased with decreased inoculum: 1 percent = 2.1 +/- 0.6 g; 0.5 percent = 0.3 +/- 0.1 g (P < 0.0001). CONCLUSIONS: Pneumoperitoneum significantly increased both tumor implantation rate and mass when approximately 3.2 x 10(5) colon cancer cells were injected into the peritoneal cavity. These effects of pneumoperitoneum diminished with one-half as many tumor cells injected in the peritoneal cavity.

Animals↗
PubMed2002

Persistent post-laparoscopy pneumoperitoneum.

BACKGROUND: Persistent pneumoperitoneum after a laparoscopic operation can represent either residual postoperative pneumoperitoneum or free intraperitoneal gas released from the gastrointestinal tract. This animal study was conducted to better characterize the extent and duration of postoperative pneumoperitoneum as detected by computed tomography (CT). METHODS: Five pigs underwent cholecystectomy, four laparoscopically and one open. All pigs were followed serially with upright chest radiographs and abdominal CT scans beginning immediately postoperatively and continuing daily until resolution of pneumoperitoneum as detected by both imaging modalities. All radiographs and CT scans were reviewed by dedicated radiologists who reported the extent and duration of pneumoperitoneum in a blinded fashion. RESULTS: Pneumoperitoneum resolved on upright chest radiographs in all five pigs by or on postoperative day 1. Serial CT scans demonstrated that the laparoscopic group had either resolution of pneumoperitoneum or minimal persistence of free intraperitoneal gas by postoperative day 2. In contrast, the single pig in the open group had CT evidence of persistent pneumoperitoneum through postoperative day 6. CONCLUSIONS: In the pig model, small pockets of free intraperitoneal gas detected by CT scanning are expected to resolve by postoperative day 2 following laparoscopic surgery. Persistence of pneumoperitoneum beyond this interval is abnormal and may represent a perforated viscus. Whereas a prospective CT imaging study in humans is not ethically feasible, we believe that parallel conclusions between the pig and human may be drawn.

Abdominal Pain↗
PubMed2005

Effect of carbon dioxide pneumoperitoneum and wound closure technique on port site tumor implantation in a rat model.

BACKGROUND: The purpose of this study was to evaluate the effects of carbon dioxide (CO2) pneumoperitoneum and wound closure technique on port site tumor implantation. METHODS: A standard quantity of rat mammary adenocarcinoma (SMT2A)was allowed to grow in a flank incision in Wistar-Furth rats (n = 90) for 14 days. Thereafter, 1-cm incisions were made in each animal in three quadrants. There were six control animals. The experimental animals were divided into a 60-min CO2 pneumoperitoneum group (n = 42) and a no pneumoperitoneum (n = 42) group. The flank tumor was lacerated transabdominally in the experimental groups. The three wound sites were randomized to closure of (a) skin; (b) skin and fascia; and (c) skin, fascia, and peritoneum. The abdominal wounds were harvested en bloc on postoperative day 7. RESULTS: Histologic comparison of the port sites in the pneumoperitoneum and no-pneumoperitoneum groups did not demonstrate a statistically significant difference in tumor implantation for any of the closure methods. Evaluation of the closure techniques showed no statistical difference between the pneumoperitoneum group and the no-pneumoperitoneum group in the incidence of port site tumor implantation. Within the no-pneumoperitoneum group, there was a significant increase (p = 0.03) in tumor implantation with skin closure alone vs all three layers. Additionally, when we compared all groups by closure technique, the rate of tumor implantation was found to be significantly higher (p = 0.01) for skin closure alone vs closure of all three layers. CONCLUSIONS: This study suggests that closure technique may influence the rate of port site tumor implantation. The use of a CO2 pneumoperitoneum did not alter the incidence of port site tumor implantation at 7 days postoperatively.

Adenocarcinoma↗
PubMed1997

Duration of postlaparoscopic pneumoperitoneum.

BACKGROUND: Patients who present with abdominal pain after recent laparoscopic surgery present a diagnostic dilemma when pneumoperitoneum is present. Previous studies do not define the duration of postlaparoscopic pneumoperitoneum. In this study, we attempted to define the duration of laparoscopic pneumoperitoneum and to identify factors which affect resolution time. METHODS: We followed 57 patients who underwent laparoscopic cholecystectomy (34), inguinal herniorraphy (20), or appendectomy (three). Serial abdominal films were taken until all residual gas was resolved. RESULTS: Thirty patients resolved their pneumoperitoneum within 24 h; 16 patients resolved between 24 h and 3 days; nine patients resolved between 3 and 7 days; two patients resolved between 7 and 9 days. Mean resolution time for all patients was 2.6 +/- 2.1 days. There was no apparent difference in resolution time between the three types of procedures; however, the sample size may be insufficient. Duration of the pneumoperitoneum did not correlate with gender, age, weight, initial volume of CO2 used, length of time for the procedure, or postoperative complications. Sixteen patients had bile spillage during cholecystectomy which significantly reduced the duration of postoperative pneumoperitoneum (p < 0.008), resulting in a mean resolution time of 1.3 +/- 0.9 days. While 14 patients reported postoperative shoulder pain, no correlation was found between the presence or duration of shoulder pain and the extent or duration of pneumoperitoneum. CONCLUSIONS: We conclude that the residual pneumoperitoneum following laparoscopic surgery resolves within 3 days in 81% of patients and within 7 days in 96% of patients. The resolution time was significantly less in patients sustaining intraoperative bile spillage during cholecystectomy. There was no correlation found between postoperative shoulder pain and the presence or duration of the pneumoperitoneum.

Adolescent↗
PubMed2004

Effect of adding more than 3% oxygen to carbon dioxide pneumoperitoneum on adhesion formation in a laparoscopic mouse model.

OBJECTIVE: To investigate the effect of the addition of 3% or higher oxygen concentrations to the carbon dioxide (CO2) pneumoperitoneum. DESIGN: Prospective, randomized trial. SETTING: Academic research center. ANIMAL(S): Female Naval Medical Research Institute mice (n = 100). INTERVENTION(S): Sixty minutes of CO2 pneumoperitoneum with 0%, 3%, 6%, 9%, or 12% oxygen; induction of adhesions by the creation of standardized peritoneal lesions during laparoscopy. MAIN OUTCOME MEASURE(S): Adhesions were quantitatively and qualitatively scored after 7 days during laparotomy to determine [1] the effect of 60 minutes of CO2 pneumoperitoneum with 0%, 3%, 6%, 9%, or 12% oxygen on adhesion formation, and [2] the effect of duration of CO2 pneumoperitoneum and insufflation pressure on adhesion formation with the addition of 0%, 3%, and 12% oxygen. RESULT(S): Compared with a CO2 pneumoperitoneum with 3% oxygen, adhesion formation is greater when either no oxygen or more than 3% oxygen is added to the CO2 pneumoperitoneum. These effects persisted at higher insufflation pressures and longer duration of pneumoperitoneum, both known to increase adhesion formation with pure CO2. CONCLUSION(S): This study confirms that adhesion formation is decreased with the addition of 3% oxygen to the CO2 pneumoperitoneum. The addition of higher oxygen concentrations, however, is deleterious. Adhesions always increase with time and duration of the pneumoperitoneum.

Animals↗
PubMed2003

Role of the plasminogen system in basal adhesion formation and carbon dioxide pneumoperitoneum-enhanced adhesion formation after laparoscopic surgery in transgenic mice.

OBJECTIVE: To evaluate the role of plasminogen activator inhibitor-1 (PAI-1), urokinase plasminogen activator (uPA), and tissue-type plasminogen activator (tPA) in adhesion formation after laparoscopic surgery. DESIGN: Prospective, randomized study. SETTING: Academic research center. ANIMAL(S): Seventy female wild-type and transgenic knockout mice for PAI-1 (PAI-1(-/-)), uPA (uPA(-/-)) or tPA (tPA(-/-)). INTERVENTION(S): Standardized lesions to induce peritoneal adhesions were performed during laparoscopy. To evaluate basal adhesions and pneumoperitoneum-enhanced adhesions, the pneumoperitoneum was maintained for 10 minutes or 60 minutes, respectively. Peritoneal biopsy samples were obtained during and after 60 minutes of carbon dioxide pneumoperitoneum. MAIN OUTCOME MEASURE(S): Adhesions were blindly scored after 7 days. Concentrations of PAI-1 and tPA were measured by using enzyme-linked immunosorbent assay. RESULT(S): In PAI-1, uPA, and tPA wild-type mice, pneumoperitoneum enhanced adhesions. Compared with wild-type mice, basal adhesions were fewer in PAI-1(-/-) mice and more in uPA(-/-) and tPA(-/-) mice. Pneumoperitoneum did not enhance adhesions in these transgenic mice. PAI-1 concentration increased after 60 minutes of pneumoperitoneum whereas tPA concentration did not change. CONCLUSION(S): Impaired fibrinolysis increases basal adhesions. The absence of pneumoperitoneum-enhanced adhesions in PAI-1(-/-), uPA(-/-), and tPA(-/-) mice and the increase in PAI-1 expression indicate that PAI-1 up-regulation by carbon dioxide pneumoperitoneum is a mechanism of pneumoperitoneum-enhanced adhesion formation.

Animals↗