Laparoscopic cecal ligation and puncture in the rat. Surgical technique and preliminary results

Carbon dioxide pneumoperitoneum–mediated attenuation of the inflammatory response is independent of systemic acidosis

BACKGROUND

The purpose of this study was to determine if systemic acidosis induced by peritoneal absorption of carbon dioxide (CO2 ) during laparoscopy plays a role in CO2 pneumoperitoneum-mediated attenuation of the acute phase inflammatory response associated with perioperative sepsis. The influence of hepatic polymorphonuclear (PMN) leukocyte infiltration on this phenomenon was also investigated.

METHODS

Forty-five rats were randomized into 5 groups: anesthesia control, open cecal ligation and puncture (OCLP), laparoscopic cecal ligation and puncture using helium for insufflation (He LCLP), LCLP using CO2 with continued spontaneous ventilation (LCLP-SV), and LCLP using CO2 with intubation and positive pressure ventilation (LCLP-PPV).

RESULTS

After 30 minutes, arterial blood gas parameters remained normal in control, OCLP rats, and He LCLP rats, while CO2 LCLP-SV rats developed significant hypercarbic acidosis. This acidosis was corrected in CO2 LCLP-PPV rats ( P < .0001 vs CO2 LCLP-SV for both). Expression of the rat acute phase gene alpha 2 -macroglobulin was greater after OCLP and He LCLP than after either CO2 LCLP-SV or CO2 LCLP-PPV ( P < .0001 vs either CO2 OCLP-SV for both). However, levels of alpha 2 -macroglobulin were not significantly different between the acidotic (LCLP-SV) and normocarbic (LCLP-PPV) CO2 groups. Infiltration of the hepatic parenchyma by PMNs did not differ significantly between groups.

CONCLUSIONS

CO2 insufflation-induced systemic acidosis is not responsible for the reduction in the acute phase inflammatory response observed in laparoscopic animal models of sepsis. Hepatic PMN infiltration also does not appear to mediate this effect.

Modelo experimental de esplenectomia laparoscópica em ratos

OBJETIVO: Desenvolver um modelo de esplenectomia laparoscópica em ratos. MÉTODOS: Foram utilizados trinta e cinco ratos machos ( Rattus Norvegicus Albinus, linhagem Wistar),pesando 250 +/- 50 g .Os animais foram anestesiados com cetamina e xylazina e foi estabelecido pneumoperitônio de CO2 com pressão de 7 mmHg, através da agulha de Veress. Após pneumoperitônio, dois trocateres de 5 mm e um de 11mm foram alocados na parade abdominal obedecendo a triangulação. O ligamento gastroesplênico foi dissecado para mobilização do baço. Os vasos hilares foram dissecados e eletrocoagulados utilizando a pinça "Maryland" e o gancho "HooK". Um "endobag" adaptado, foi utilizado para retirar o orgão da cavidade abdominal. RESULTADOS: Um animal (2,86%) morreu na indução anestésica. Após um período de observação de oito dias, trinta animais sobreviveram (85,7 %) e quatro (11,42%) Morreram no pós-operatório imediato. Em relação às complicações, Aderências intra-abdominais foram encontradas em 25,71% dos animais (n=9). CONCLUSÃO: A esplenectomia laparoscópica é um modelo factível por conta da baixa taxa de mortalidade além do baixo custo para treinamento da técnica.

CO2 Pneumoperitoneum modifies the inflammatory response to sepsis

OBJECTIVE

To analyze the effect of CO2 pneumoperitoneum on the inflammatory response induced by sepsis during laparoscopy.

SUMMARY BACKGROUND DATA

A growing body of evidence challenges the once generally accepted notion that smaller incisions alone account for the observed benefits of the laparoscopic approach. Furthermore, laparoscopic surgery is now being applied to a broad spectrum of patients, including those in whom the inflammatory response is ignited. Delineation of the effects of CO2 pneumoperitoneum on the inflammatory response induced by sepsis is needed.

METHODS

Sepsis was induced in rats by cecal ligation and puncture (CLP) performed either open or laparoscopically using CO2 or helium as insufflation gases. Animals were killed 24 hours postoperatively, at which time whole blood was collected for complete blood cell counts and livers were harvested for analysis of hepatic expression of the rat acute phase genes alpha2-macroglobulin and beta-fibrinogen.

RESULTS

Laparoscopic CLP using CO2 resulted in significantly reduced hepatic expression of the rat acute phase gene alpha2-macroglobulin compared to both laparoscopic CLP using helium and open CLP. Hepatic expression of another rat acute phase gene, beta-fibrinogen, paralleled that of alpha2-macroglobulin and was significantly reduced following laparoscopic CLP using CO2 compared to laparoscopic CLP using helium. Total white blood cell and neutrophil counts following CLP were both significantly higher when CLP was performed laparoscopically using CO2 than when CLP was performed open or laparoscopically using helium.

CONCLUSIONS

Intra-abdominal CO2 present during laparoscopy attenuates the acute phase inflammatory response associated with perioperative sepsis.

Common laparoscopic procedures in swine: a review

Swine serve as excellent models for many laparoscopic procedures. As more operations are being performed laparoscopically, it is essential for the surgeon to have a good understanding of laparoscopic techniques. This manuscript reviews some commonly performed laparoscopic operations with an emphasis on models in swine. Porcine anatomy is generally similar to human anatomy with some minor differences. Practice on porcine models can help refine techniques and increase efficiency and skill.