The effects of intraabdominally insufflated carbon dioxide on hepatic blood flow during laparoscopic surgery assessed by transesophageal echocardiography

Conflicting results have been published about the effects of carbon dioxide (CO(2)) pneumoperitoneum on splanchnic and liver perfusion. Several experimental studies described a pressure-related reduction in hepatic blood flow, whereas other investigators reported an increase as long as the intraabdominal pressure (IAP) remained less than 16 mm Hg. Our goal in the present study was to investigate the effects of insufflated CO(2) on hepatic blood flow during laparoscopic surgery in healthy adults. Blood flow in the right and middle hepatic veins was assessed in 24 patients undergoing laparoscopic surgery by use of transesophageal Doppler echocardiography. Hepatic venous blood flow was recorded before and after 5, 10, 20, 30, and 40 min of pneumoperitoneum, as well as 1 and 5 min after deflation. Twelve patients undergoing conventional hernia repair served as the control group. The induction of pneumoperitoneum produced a significant increase in blood flow of the right and middle hepatic veins. Five minutes after insufflation of CO(2) the median right hepatic blood flow index increased from 196 mL/min/m(2) (95% confidence interval (CI), 140-261 mL/min/m(2)) to 392 mL/min/m(2) (CI, 263-551 mL/min/m(2)) (P < 0.05) and persisted during maintenance of pneumoperitoneum. In the middle hepatic vein the blood flow index increased from 105 mL/min/m(2) (CI, 71-136 mL/min/m(2)) to 159 mL/min/m(2) (CI, 103-236 mL/min/m(2)) 20 min after insufflation of CO(2). After deflation blood flow returned to baseline values in both hepatic veins. Conversely, in the control group hepatic blood flow remained unchanged over the entire study period. We conclude that induction of CO(2) pneumoperitoneum with an IAP of 12 mm Hg is associated with an increase in hepatic perfusion in healthy adults.     

Effects of carbon dioxide pneumoperitoneum on hepatic function in obstructive jaundice: an experimental study in a rat model

Background and aims  

The physiology of the patient during laparoscopy differs from that of open surgery. Both pneumoperitoneum and obstructive jaundice impair the hepatic function, but the combined insult has not been previously examined. In this study, we aimed to investigate the effects of carbon dioxide (CO₂) pneumoperitoneum on hepatic function in a rat model of obstructive jaundice.     

Subcutaneous tissue oxygen and carbon dioxide tensions during hyperbaric oxygenation: an experimental study in rats.

OBJECTIVE: To investigate the response of subcutaneous tissue oxygen (O2) and carbon dioxide (CO2) tensions to hyperbaric oxygenation. DESIGN: Experimental study. SETTING: University hospital, Finland. SUBJECTS: 10 Wistar rats. INTERVENTION: Subcutaneous tissue PO2 and PCO2 were directly measured with an implanted Silastic tube tonometer and capillary sampling technique while breathing air and exposed to hyperbaric oxygen (HBO) at 2.5 or 2.8 ATA pressure. Hyperbaric exposures were carried out in a large multiplace chamber pressurised with air. MAIN OUTCOME MEASURES: Subcutaneous tissue PO2 and PCO2. RESULTS: The mean subcutaneous PO2 rose from the baseline of 8 kPa (60 mmHg) to 16 kPa (112 mmHg) when rats breathed room air during pressurisation to 2.8 atm. When the rats breathed oxygen at 2.5 ATA the maximal mean tissue PO2 was four times higher than the mean starting value. During the HBO treatment at 2.8 ATA the tissue PO2 rose to a value about five times above baseline. The tissue PCO2 values almost doubled during the exposure to HBO at 2.5 ATA, probably because elimination of carbon dioxide was impaired. CONCLUSION: Measurements of tissue PO2 and PCO2 with an implanted Silastic tonometer and a capillary sampling technique can successfully be adapted to hyperbaric conditions. The method yielded reproducible results and is applicable to clinical use in hyperbaric medicine.     

Effect of intraabdominal pressure elevation and positioning on hemodynamic reponses during carbon dioxide pneumoperitoneum for laparoscopic donor nephrectomy: a prospective controlled clinical study

Background Carbon dioxide (CO₂) pneumoperitoneum (PP) increases mean arterial blood pressure (MAP) and systemic vascular resistance (SVR) but decreases stroke volume (SV) and cardiac output (CO). This study evaluated the hemodynamic effects of elevated intraabdominal pressure (IAP) occurring during laparoscopic donor nephrectomy (LDN).Methods Twenty-two patients undergoing LDN were investigated and hemodynamic parameters, P_vCO₂ (carbon dioxide partial pressure), and VCO₂ (carbon dioxide production) were monitored during the procedure. Before and after PP, IAP was raised from 12 to 20 mmHg and the hemodynamic effects were measured every 30 s.Results During IAP of 12 mmHg and stable serum CO₂, there was no change in SV compared to preinsufflation levels. When IAP was elevated from 12 to 20 mmHg, SV initially decreased (p < 05), followed by an increase in MAP and SVR (p < 0.05).Conclusion This study shows that with the fluid and ventilation protocol used, PP has no significant effect on SV at an IAP of 12 mmHg, whereas increasing IAP to 20 mmHg does. In this study, the hemodynamic effects induced by CO₂ PP of 12 mmHg are not due to changes in serum CO₂ . Compression of the venous system during a PP of 20 mmHg reduces preload, with an subsequent increase in SVR.     

一氧化氮对术后腹膜粘连作用的实验研究

目的研究一氧化氮 (NO)在预防大鼠术后腹膜粘连中的作用。方法 40只大鼠统一制作腹膜粘连模型 ,随机分为对照组和左旋精氨酸组。术后分别腹腔内注射 0 9%NaCl和左旋精氨酸 ,连续 3d。术后 3d随机抽取部分大鼠血样测定NO ,同时取材作病理检查。其余大鼠 2周后乙醚处死开腹观察并记录粘连情况。结果对照组的粘连分级 (3 7± 0 7)重于左旋精氨酸组 (0 9±1 1) ,t=8 6 ,P <0 0 1。对照组血中NO的水平为 (13 9± 1 1) μmol/L ,低于左旋精氨酸组 (32 2± 2 8)μmol/L ,t=2 0 4,P <0 0 1。左旋精氨酸组粘连组织中诱导型一氧化氮合酶 (iNOS)的免疫组化染色分级为 2 5± 0 7强度高于对照组 (0 8± 0 4) ,t=11 1,P <0 0 1。结论一氧化氮在腹膜粘连的预防中起重要作用     

Effects of hyaluronic acid on postoperative adhesion of tendo calcaneus surgery: an experimental study in rats.

Adhesions are a significant problem after tendon surgery. The effects of hyaluronic acid on adhesion formation of the tendo calcaneus were investigated in this study. Twenty Wistar rats were utilized. Both tendo calcanei were incised transversely, and then repaired. Hyaluronic acid (0.2 cc) was injected into peritendinous tissue on the right side, while the same amount of normal saline was injected to the left side as a control. The animals were sacrificed 40days after the experiment. Both the right and left tendon adhesions were evaluated both macroscopically and microscopically for the presence of adhesions (grading scale 0-4). Throughout the experimental period, there was no difference in range of motion of the ankle between the two groups. Macroscopically, there were fewer adhesions in the experimental group (mean 0.6 +/- 0.8) compared to the controls (mean 1.1 +/- 0.2). This difference was not statistically significant (p = .096). Histopathologically, these parameters were similar in both the experimental (mean 1.15 +/- 0.98) and the control groups (mean 1.9 +/- 1.25). This difference was significant (p = .043). Hyaluronic acid may be effective for prevention of adhesions in the tendo calcaneus though this effect could not be demonstrated experimentally.     

Valsalva maneuver biomechanics. Effects on lumbar trunk loads of elevated intraabdominal pressures

The ability of a partial or full Valsalva maneuver (voluntary pressurization of the intraabdominal cavity) to unload the spine was investigated in four subjects. During the performance of five isometric tasks, intraabdominal and intradiscal pressures and surface myoelectric activities in three lumbar trunk muscle groups were measured. The tasks were carried out without voluntary pressurization of the intraabdominal cavity and then when the subjects performed partial and full Valsalva maneuvers. A biomechanical model analysis of each task was made to help interpret the experimental measurements. Intraabdominal pressure was found not to be an indicator of spine load in these experiments. The Valsalva maneuvers did raise intraabdominal pressure, but in four of the five tasks increased rather than decreased lumbar spine compressions occurred.     

Effect of paralysis of the abdominal wall muscles by botulinum A toxin to intraabdominal pressure: an experimental study

Purpose

To show the effect of botulinum A toxin-induced paralysis of abdominal muscles on intraabdominal pressure.

Material and Methods

Fifteen Sprague-Dawley rats were divided into 2 groups. An abdominal skin incision was done, and 2 catheters were placed for the pressure monitoring and saline infusion. Saline solution was given to the abdomen until reaching to a pressure level of 9 cm H₂O and 6 mm Hg in pressure device, and the amounts of injected saline were recorded. Then intraabdominal saline was drained. Two milliliters (5 U/mL) botulinum A toxin was applied to the abdominal muscles in group 2. Saline was injected at the same points in same amounts in group 1. After 3 days, catheters were placed, and the saline volumes needed to obtain the same pressure levels were recorded for each rat. Spontaneous motor unit potential (MUP), single MUP analysis and interference patterns of the muscles, respiratory rates, and vascular pressure measurements were recorded before and after botulinum toxin (Botox) injections.

Results

Mean intraabdominal saline volumes in the first and third days were 63.8 and 64.4 mL in group 1 and 67.6 and 80.6 mL in group 2, respectively. Mean MUP amplitude and duration of the rectus muscles in group 2 (17.1 μV and 1.47 milliseconds) were significantly lower than those of group 1 (187 μV and 4.9 milliseconds) in the third day. There were no pathological changes in respiratory rates and pressure measurements before and after Botox injections.

Conclusion

This pilot experimental study showed that local injection of botulinum A toxin causes paralysis in abdominal wall muscles, increases the intraabdominal volume, and decreases the pressure, and this application may be used as an adjunct in abdominal wall closure in selective cases.     

An experimental study evaluating the effect of Mitomycin C on the prevention of postoperative intraabdominal adhesions

BACKGROUND: Fibroblast proliferation is one of the well-known mechanisms for postoperative intraabdominal adhesion formation. Inhibition of fibroblast proliferation is an attractive field of investigation in the prevention of adhesions. Mitomycin C (MMC) is a cytotoxic agent that alkylates and crosslinks DNA and also inhibits fibroblast proliferation up to a few weeks. We aimed to determine the effect of MMC on the prevention of adhesions. MATERIALS AND METHODS: Generation of adhesions in rats by brushing a 1-cm(2) area of the cecum and the peritoneum on the right side of the abdominal wall was followed by intraperitoneal administration of saline, 1 mg/kg MMC, and 0.5 mg/kg MMC in saline. After 45 days, formation of adhesions was graded. RESULTS: The average adhesion scores of the control, and MMC (1 mg/kg), MMC (0.5 mg/kg) groups were 3.2 +/- 0.7, 0.8 +/- 0.6, and 0.7 +/- 0.8, respectively. Adhesion scores of the two MMC-treated groups were significantly lower than that of the control group (P < 0.001). There was no difference between the two MMC groups (P > 0.05). No side effect of MMC was observed. CONCLUSION: MMC was found to be very effective in the prevention of postoperative intraabdominal adhesions.     

The effects of renal pelvic pressure elevation on isotope nephrography and renal transit time, an experimental study

Radionuclide procedures are clinically used for assessing obstruction in dilated urinary tracts. The precise correlation of the isotope retention function with the level of the renal pelvic pressure is not known as yet. It was measured experimentally using 20 minipigs. By means of ureterostomies in situ reaching into the pyelon the 40 kidneys were subjected to varying pressures (seven to 62 cm. H2O) while the renal processing of 123-I-orthoiodine-hippuric-acid was recorded. The correlation of five radionuclide parameters with the pelvic pressure was computed: the time to the peak value of the isotope nephrography (t-max) and renal transit time correlated very well with high grade pelvic pressure (greater than 37 cm. H2O): r = 0.91 and 0.86 respectively, but much less well with low grade pelvic pressure (less than 37 cm. H2O): r = 0.73 and 0.62 respectively. The slope of the third phase of the isotope nephrography (tan-turn) and the time to the turning point of its tangent (t-turn) correlated only weakly with elevated renal pelvic pressure: r = 0.62 and 0.59 respectively. In conclusion, radionuclide procedures give excellent qualitative information on the level of pelvic pressure. They cannot, however, be used even as an indirect means for quantitatively assessing elevated renal pelvic pressure, which in urinary obstruction is thought to be one of the factors jeopardizing renal function.     

Effect of postoperative irradiation on free skin flaps: an experimental study in rats.

The modern treatment of musculoskeletal malignant tumours often requires different combinations of surgery, chemotherapy, and radiotherapy. Although combination treatments have allowed reconstruction of more complex defects, the risk of complications also rises. In clinical series the complication rate is influenced by the characteristics of the defect and the quality of the radiation used. The flap survival is high, but the overall complication rate is more than 25%. In this study we looked at the healing of microvascular free skin flaps exposed to postoperative irradiation in a rat model. Epigastric microvascular free skin flap were exposed to a single dose of 20 Gy radiation one week postoperatively (n = 8). A comparison was made with free epigastric skin flaps without postoperative radiation (n = 8). The healing was assessed histologically at four weeks and by measuring the tensile strength of the wound. Biochemical total nitrogen and hydroxyproline contents were also measured. Results showed that histologically the interfaces healed similarly with only minimal histomorphological changes. Neither the mechanical strength of the healing interface nor the biochemical markers altered significantly. Postoperative irradiation with a single dose of 20 Gy does not affect the survival of free skin flaps in rats. In the future the model described could be used to study the effects of combination therapy of surgery, radiotherapy, and chemotherapy more closely to find the optimal control of malignancies with limited damage to treated tissue.     

不同CO2气腹压力对腹腔镜胆囊切除术后肩痛的影响

目的研究不同CO2气腹压力对腹腔镜胆囊切除术(LC术)后肩部疼痛的影响。方法将100例行LC术的患者随机分为两组,每组50例,分别设定气腹压力为1.2kPa(10mmHg)和2kPa(15mmHg)下行LC术。对比两组术后肩部疼痛发生率及程度。结果在1.2kPa下手术组,患者的术后肩部疼痛程度明显低于2kPa手术组,差异有统计学意义(χ2=22.698,P<0.05)。结论LC术后肩部疼痛的主要原因可能与人工气腹张力对膈肌牵拉刺激有关。在10mmHg低压气腹下行LC术,可显著降低LC术后肩部疼痛的发生率及程度。     

不同压力CO2气腹对腹腔镜胆囊切除术后肩部疼痛发病影响的临床观察

目的研究腹腔镜胆囊切除术 (laparoscopiccholecystectomy ,LC)后肩部疼痛发生的原因、机理及防治方法。方法将 12 0例行LC的患者随机分为A、B、C组 ,每组 4 0例。气腹压力设定A组 10mmHg ,B组 12mmHg ,C组 14mmHg。观察 3组术前、术后的PaO2 、PaCO2 、动脉血 pH值以及术后 1、3、6、12、2 4、4 8、72、96h肩痛的发生率和疼痛程度 (视觉模拟评分 VAS)。结果术中CO2 用量C组较A组多 ,差异有显著意义 (F =11 38,P <0 0 5 )。C组术前、术后的PaO2 差值与A、B组术前、术后PaO2 差值相比较大 ,且差异有显著意义 (F =6 92 ,P <0 0 1)。随 3组气腹压力的增高 ,术后 3、12、2 4、4 8h肩痛发生率有增高趋势 (χ2 值分别为 2 36 6 ,2 32 4 ,2 72 9,2 340 ,P <0 0 5 ) ;其VAS评分也明显上升 (F =19 5 3,P <0 0 1)。结论LC术后肩痛的主要原因可能与人工气腹张力对膈肌的牵拉有关。在 10mmHg低压气腹下行LC ,可显著降低LC术后肩痛的发生率及疼痛程度。     

Preventing recurrent postoperative adhesions: an experimental study in rats

A peritoneal lavage model, cyclic intraperitoneal lavage (CIPL), and other adhesion preventing methods with and without fibrinolytic agents were compared to a control group without treatment in an animal study. The adhesion-preventing effect was evaluated at the site of a standardized peritoneal defect (free peritoneal grafting, P) and at the laparotomy wound (L) of 60 rats (12 escape) after surgical lysis of primary adhesions during relaparotomy In five test groups with different treatments and in a control group without treatment recurrent adhesions were investigated during relaparotomy according to an adhesion grading scale with increasing severity (O-III). In the control group only severe adhesions grade II and III were observed. The five test groups showed different distributions of grade 0-II adhesions: compared to the control group a significant difference of the preventing effect was seen after CIPL with 1.36% glucose solution (as used for peritoneal dialysis) and after CIPL with Ringer's solution at the sites P and L, after a one-time irrigation with Ringer's solution only at the peritoneal graft P. Fibrinolytic agents used in CIPL or as single dose application failed to show an improvement compared to the control group.     

Effect of carbon dioxide pneumoretroperitoneum on bacterial translocation in an experimental retroperitoneoscopy model

PURPOSE: To evaluate the effect of artificial CO2 pneumoretroperitoneum on bacterial translocation in an experimental retroperitoneoscopy model. MATERIALS AND METHODS: Eighteen adult male New Zealand White rabbits weighing 2.5 to 3 kg were divided into two groups. Group 1 (control group) consisted of 6 rabbits, while the remaining 12 served as the pneumoretroperitoneum group (group 2). In group 1, the left retroperitoneal space was dissected with a 50-mL balloon without CO2 insufflation, and the animals were kept under anesthesia for 3 hours with the balloons inflated. In group 2, after balloon dissection as in group 1, CO2 insufflation was applied at 1 L/min to achieve a pressure of 10 to 12 mm Hg for 3 hours. Afterward, all animals were sacrificed, and samples were taken from the blood, retroperitoneal area, lungs, liver, mesentery, heart, kidneys, ureters, bladder, colon, small intestine, and spleen and carried to the microbiology laboratory in Carry-Blair medium. Bacterial growth was evaluated using standard techniques. RESULTS: All animals survived the experimental procedures. None of the rabbits in the control group demonstrated any bacterial translocation in the sampled tissues. In the pneumoretroperitoneum group, one rabbit was found to have 10(2) colony-forming units of E. coli in the kidney, but this was considered to be the result of contamination, not translocation. CONCLUSION: Carbon dioxide pneumoretroperitoneum does not seem to cause bacteremia or bacterial translocation in this experimental model. Retroperitoneoscopy probably does not create any additional risk of septic complications.     

CO2气腹及肠道牵拉引起大鼠应激反应的实验研究

目的研究CO2气腹及肠道牵拉对SD大鼠血浆β-内啡肽(β-endorphin,β-EP)的影响,探讨CO2气腹及肠道牵拉对大鼠围手术期应激反应的影响. 方法选取SPF级雄性SD大鼠120只,随机分为4组,每组30只.A组:CO2气腹组;B组:切口组;C组:切口并肠道牵拉组;D组:对照组.测定A、B和C组大鼠切皮后血浆10 min、20 min和40 min的血浆β-EP浓度,比较CO2气腹及肠道牵拉对应激反应的影响. 结果 CO2气腹组术后10 min、20 min和40 min的血浆β-EP浓度分别为(274.7±66.6)pg/dl、(157.3±63.8)pg/dl和(163.9±74.5)pg/dl,与对照组比较有非常显著升高(P<0.01).切口并肠道牵拉组术后10 min、20 min和40 min的β-EP浓度分别为(376.9±50.8)pg/dl、(298.8±70.0)pg/dl和(266.9±53.7)pg/dl,与气腹组比较两组术后10 min、20 min β-EP有非常显著差异(P<0.01),术后40 min有显著差异(P<0.05).切口并肠道牵拉组与切口组比较两组术后10 min、20 min和40 min β-EP均有非常显著差异(P<0.01). 结论 CO2气腹及肠道牵拉为重要的刺激因素,均可以引起大鼠的应激反应,肠道牵拉可加重应激反应的程度.     

Fat and dermofat isografts: an experimental study in mice

Summary A long-term (27 months) experimental study in mice was designed to elucidate the origin and fate of grafted adipose cells at the recipient site. That cells originated from the donor rather than the recipient was suggested in certain cases but not clearly demonstrated. Presence of the dermis in dermo-fat grafts did not enhance the take. An important parameter of the graft survival was the vascular pattern of the transplant. Vascularization by a major artery seemed to ensure preservation of up to 75% of the volume of the graft.