Safe and novel technique for peritoneal access in urologic laparoscopy without prior insufflation

BACKGROUND AND PURPOSE: Access to the peritoneum for transperitoneal laparoscopic surgery can be achieved using a variety of techniques, each of which has advantages and disadvantages as well as risks of complications. The endoscopic threaded imaging port (EndoTIP) is a metal, reusable, threaded visual-access cannula that is inserted by rotational rather than axial force. When the technique was described initially, capnoperitoneum was obtained prior to trocar insertion. We describe the results of our series using the EndoTIP port without prior capnoperitoneum. PATIENTS AND METHODS: All 165 patients who underwent urologic transperitoneal laparoscopic procedures using the EndoTIP performed by a single surgeon from October 2001 through June 2005 were reviewed. Twentyfive patients were morbidly obese, and 32 had had previous abdominal surgical procedures. All data regarding patient demographics, details of the procedures, and outcomes were obtained from a database developed for prospective data collection at our institution. RESULTS: There were no complications associated with peritoneal access or trocar insertion. The average time required to obtain capnoperitoneum was <1 minute. CONCLUSIONS: Insertion of the EndoTIP port without prior capnoperitoneum is a safe, quick, and reliable method for peritoneal access in laparoscopic surgery. By avoiding blind punctures of the abdominal cavity, the risk of complications during access is minimized. We believe this technique should be considered in preference to techniques where trocars are inserted blindly.     

Tumor implantation following laparoscopy using different insufflation gases

Background: Laparoscopic manipulation of malignancies is associated with an increased incidence of metastasis to port sites in experimental models. This study investigated the effect of different insufflation gases on the implantation of a tumor cell suspension following laparoscopic surgery in an established small animal model. Methods: Forty Dark Agouti rats underwent laparoscopy and the introduction into the peritoneal cavity of a tumor cell suspension. The insufflating gas used for each procedure was one of the following gases (10 rats in each group): carbon dioxide (CO₂), nitrous oxide (N₂O), helium, and air. The rats were killed 7 days after surgery, and the peritoneal cavity and port sites were examined for the presence of tumor. Results: Although no significant differences were seen between air, CO₂, and N₂O insufflation groups, tumor involvement of peritoneal surfaces was less likely following helium insufflation. Conclusion: The results of this study suggest that tumor metastasis to port sites following laparoscopic surgery may be influenced by the choice of insufflation gas. In this study, helium was associated with reduced tumor growth.     

Tumour implantation following laparoscopy using different insufflation gases

Background : Because of the possibility of intraperitoneal seeding and port‐site recurrences following laparoscopic surgery, the role of laparoscopy in cancer surgery remains controversial. Previous experimental studies have suggested that chemical, metabolic and immunological changes following carbon dioxide (CO₂) insufflation may be responsible for this phenomenon. Earlier experimental studies done by the University of Adelaide Department of Surgery have also shown that helium insufflation is associated with none of the adverse changes brought about by CO₂ insufflation. Helium insufflation is also associated with lower rates of intra‐abdominal tumour spread. The aim of this study was to determine whether these identified benefits apply to inert gases in general. Methods : Twenty‐four Dark Agouti rats were randomized to undergo laparoscopy with 40 min insufflation using one of the following four gases (six rats in each group); CO₂, helium, argon and nitrogen. A tumour cell suspension was injected into the abdominal cavity at the beginning of laparoscopy. The rats were killed 7 days after surgery, and the peritoneal cavity and port sites were examined for the presence of tumour. Results : Rats undergoing helium insufflation, had the least number of port‐site recurrences and the least amount of intraperitoneal tumour spread. Argon and nitrogen pneumoperitoneum were associated with a large number of port‐site recurrences and widespread tumour seeding. The effect of CO₂ insufflation was intermediate. Conclusion : The choice of insufflation gas influences the incidence of port‐site metastases and the degree of intraperitoneal tumour spread following laparoscopic cancer surgery. The reduced port‐site recurrences and intraperitoneal spread that followed helium pneumoperitoneum is likely to be a unique property of this gas rather than a property of inert gases in general.     

腹腔镜二氧化碳腹腔内与腹膜外充气的比较

用家兔对二种不同的腹腔镜入路进行充气实验研究，腹腔内组动脉二氧化碳分压平均升高１．４８ｋＰａ（１ｋＰａ＝７．５ｍｍＨｇ）；腹膜外组动脉二氧化碳分压平均升高０．６９ｋＰａ。提示二氧化碳在腹膜外充气时比在腹腔内充气时全身吸收要少，同时提示动脉血ｐＨ值和氧分压在两种入路时均无明显变化。进一步对二组行不同入路腹腔镜手术患者的血气进行分析比较，发现二组患者动脉血二氧化碳分压均有明显升高，血ｐＨ值均有明显下降，但二组间的血气变化无明显差异。考虑腹腔镜经腹入路的合并症及泌尿系统的特点，认为经腹膜外入路对多数泌尿系疾病更适宜。     

Experimental study of effect of embolism of different laparoscopy insufflation gases

BACKGROUND AND PURPOSE: Whilst carbon dioxide is the gas generally used for insufflation during laparoscopy, several studies have reported adverse effects specifically associated with its use. These effects may be attributable to chemical, metabolic, or immunologic effects specific to CO2. Because helium is chemically, physiologically, and pharmacologically inert, it has been suggested as a possible substitute insufflation gas. However, there has been concern about the potential implications of venous gas embolism during helium insufflation. The aim of this study was to examine the physiological effect of the intravenous injection of He and CO2 in an experimental model. MATERIALS AND METHODS: Eleven domestic white pigs were randomly allocated to receive multiple intravenous injections of increasing volumes of either CO2 or He gas. Cardiorespiratory function was measured, and the intravenous volumes of gas that resulted in cardiac arrest were determined. RESULT: Cardiorespiratory functional measures returned to normal quicker after CO2 than after He injection. Helium injection quickly overwhelmed the animal's ability to compensate and resulted in death at a lower volume than did CO2 injection. CONCLUSIONS: Gas embolism during He insufflation is more likely to be lethal than is CO2 embolism. This scenario is most likely following Veress needle insertion into a large vein. Therefore, if He is to be used for insufflation during clinical laparoscopy, the possibility of venous injection should be minimized by avoiding Veress needle use. Further investigation of the safety of He insufflation is warranted before a role during clinical laparoscopy can be recommended.     

Experimental study of peritoneal blood flow and insufflation pressure during laparoscopy

BACKGROUND: Port-site metastases after laparoscopic surgery may occur with greater frequency than would be expected following open resection of intra-abdominal malignancies, but the causal mechanism for this is incompletely understood. The possibility that insufflation may increase peritoneal blood flow producing a wound environment conducive to the formation of metastases was investigated.METHODS: The effects of insufflation gas type and pressure were studied in 30-kg female pigs. Pigs were divided into five groups, which were subjected to insufflation at 12 mmHg pressure with helium, insufflation at 12, 8 or 4 mmHg pressure with carbon dioxide, or laparotomy. A microsphere technique utilizing two distinct radiotracers, 99mTc-labelled macroaggregated albumin (MAA) and 51Cr-labelled MAA, was used to study blood flow to the peritoneum, liver and kidneys.RESULTS: Insufflation with carbon dioxide or helium gases had no effect on renal (P < 0.09) or hepatic blood flow (P = 0.54). However, insufflation significantly increased peritoneal blood flow when carbon dioxide (P < 0.05), but not when helium (P = 0.99), was used as the insufflating gas.CONCLUSION: These data suggest that blood flow within the peritoneum is influenced by insufflation with carbon dioxide. It is conceivable that such hyperaemia could increase the propensity for implanted tumour cells to metastasize in these sites following laparoscopy.     

Improved technique for establishing pneumoperitoneum for laparoscopy.

The establishment of a pneumoperitoneum is essential for laparoscopy. Anatomical features of the umbilicus can be used to reduce associated complications and improve the ease of creating a pneumoperitoneum.     

新生儿腹腔镜麻醉中呼吸循环功能的变化

目的：观察新生儿腹腔镜中，CO2气腹对呼吸循环系统功能的影响。方法：50例腹腔镜幽门环肌切开术的新生儿均行硬膜外麻醉辅以浅全麻，术中VT10ml/kg，调整呼吸频率使PETCO2在30－40mmHg范围内，注气前、气腹中、注气毕记录各时点的呼吸循环动力学指标。结果：气腹后，心率、MAP、PETCO2、最大吸气压（PIP）、PaCO2与注气前基础值相比均明显增高，pH值明显下降，SaO2值没有显著性变化。PETCO2在术毕10分钟内转为基础值。结论：新生儿气腹可引起呼吸循环功能的改变，使用硬膜外麻醉行腹腔镜幽门环肌切开术安全可行。     

Carbon dioxide embolism during laparoscopy: effect of insufflation pressure in pigs.

Carbon dioxide embolism is a rare but potentially devastating complication of laparoscopy. To determine the effects of insufflation pressure on the mortality from carbon dioxide embolism, six swine had intravascular insufflation with carbon dioxide for 30 seconds using a Karl Storz insufflator at a flow rate of 35 mL/kg/min. The initial insufflation pressure was 15 mm Hg. Following recovery from the first embolism, intravascular insufflation using a pressure of 20 mm Hg at the same flow rate was performed in the surviving animals. Significantly less carbon dioxide (8.3 +/- 2.7 versus 16.7 +/- 3.9 mL/kg; p < 0.02) was insufflated intravascularly at 15 mm Hg than at 20 mm Hg pressure. All of the pigs insufflated at 15 mm Hg pressure with a flow rate of 35 mL/kg/min survived. In contrast, 4 of the 5 pigs insufflated at 20 mm Hg pressure died. The surviving pig died when insufflated with 25 mm Hg pressure following an embolism of 15.7 mL/kg. Intravascular injection was often associated with an initial rise in end-tidal carbon dioxide tension, followed by a rapid fall in all cases where the embolism proved fatal. Insufflation should be begun with a low pressure and a slow flow rate to limit the volume of gas embolized in the event of inadvertent venous cannulation. Insufflation should immediately be stopped if a sudden change in end-tidal carbon dioxide tension occurs.