Intestinal perfusion during pneumoperitoneum with carbon dioxide, nitrogen, and nitric oxide during laparoscopic surgery

Ischemic conditioning of the gastric conduit prior to esophagectomy improves mucosal oxygen saturation

BACKGROUND

Ischemic conditioning of the gastric conduit is considered as a possible approach to improve perfusion of the gastric tube after esophagectomy. The aim of this study was to assess the impact of ischemic conditioning on gastric microcirculation in a clinical setting.

METHODS

Nineteen patients with an esophageal carcinoma were included. In a first laparoscopic procedure, the stomach was devascularized by complete gastric mobilization including ligation of the left gastric artery ("laparoscopic gastrolysis"). After a delay of 4 to 5 days, all patients underwent a transthoracic esophagectomy and reconstruction with the prepared gastric conduit (Ivor-Lewis). Mucosal oxygen saturation (MOS, sulfur dioxide in %) was quantitatively measured from the endoluminal side in well-defined areas of the antrum, corpus, and fundus using a tissue spectrometer located at the tip of a microprobe (LEA, Medizintechnik, Giessen, Germany). Under general anesthesia, sulfur dioxide measurement I was taken before, and measurement II after laparoscopic gastric mobilization; measurement III was done before esophagectomy and reconstruction 4 to 5 days later.

RESULTS

Before laparoscopic mobilization of the stomach the median MOS of the fundus was 72% (range, 49% to 86%). The MOS significantly decreased after devascularization of the stomach (median MOS, 38%; range, 9% to 86%). After 4 to 5 days, MOS almost recovered to values observed before gastric mobilization (median MOS, 62%; range, 48% to 85%). Compared with the fundus, no significant sulphur dioxide changes were detected in the corpus and antrum.

CONCLUSIONS

This study demonstrates that ischemic conditioning influences microcirculation of the gastric conduit and improves MOS in the anastomotic region at the time of reconstruction.

Hemodynamic and tissue blood flow responses to long-term pneumoperitoneum and hypercapnia in the pig

BACKGROUND

Increased peritoneal blood flow may influence the ability of cancer cells to adhere to and survive on the peritoneal surface during and after laparoscopic cancer surgery. Carbon dioxide (CO2) pneumoperitoneum is associated with a marked blood flow increase in the peritoneum. However, it is not clear whether the vasodilatory effect in the peritoneum is related to a local or systemic effect of CO2.

METHODS

In this study, 21 pigs were exposed to pneumoperitoneum produced with either CO2 (n = 7) or helium (He) (n = 7) insufflation at 10 mmHg for 4 h, or to two consecutive levels of hypercapnia (7 and 11 kPa) (n = 7) produced by the addition of CO2 to the inhalational gas mixture. Tissue blood flow measurements were performed using the colored microsphere technique.

RESULTS

Blood flow in peritoneal tissue increased during CO2, but not He, pneumoperitoneum, whereas it did not change at any level of hypercapnia alone. There was no change in blood flow in most organs at the partial pressure of CO2 (PaCO2) level of 7 kPa. However, at a PaCO2 of 11 kPa, blood flow was increased in the central nervous system, myocardium, and some gastrointestinal organs. The blood flow decreased markedly in all striated muscular tissues during both levels of hypercapnia.

CONCLUSION

The effect of CO2 on peritoneal blood flow during laparoscopic surgery is a local effect, and not attributable to central hemodynamic effects of CO2 pneumoperitoneum or high systemic levels of CO2.

Microsphere intestinal blood flow analysis during pneumoperitoneum using carbon dioxide and helium

BACKGROUND

Pneumoperitoneum has been associated with a decreased flow in the superior mesenteric artery and portal venous system. Intestinal blood flow was studied during a 2-h pneumoperitoneum with carbon dioxide (CO2) or helium in a porcine model using colored microspheres.

METHODS

For this study, 12 pigs were divided into two groups (6 CO2 and 6 helium). Different colored microspheres were injected directly into the left ventricle before, 40, 80, and 120 min after insufflation with either gas at a pressure of 15 mmHg. Microsphere concentration was measured in the mucosa and muscularis/serosa layers of the jejunum, cecum, and sigmoid colon to calculate blood flow.

RESULTS

Intestinal perfusion initially increases with insufflation and returns to near baseline levels during pneumoperitoneum of 2 h. The effect of helium on tissue perfusion is similar to that of carbon dioxide.

CONCLUSIONS

Intestinal perfusion does not change significantly during prolonged pneumoperitoneum at a pressure of 15 mmHg with CO2 or helium.

Blood flow distribution during elevated intraperitoneal pressure in the rat

AIM

Oliguria is seen during elevated intraperitoneal pressure, but the physiological mechanisms are not yet clarified. The purpose of the present study was to investigate the changes in renal function, cardiac output and distribution of systemic blood flow (BF) that occur in connection with an elevation of intra-abdominal pressure (IAP) in a rat model by isotope-labelled microsphere technique.

METHODS

A 5 or 10 mmHg IAP was created by CO2 insufflation and maintained for 90 min in anaesthetized and mechanically ventilated rats. Rats with normal IAP served as controls. Blood flow and cardiac output measurements by injection of isotope-labelled microspheres were conducted at three time points. Acid-base balance, urine output, glomerular filtration rate (GFR) and urinary excretion products were also followed.

RESULTS

Glomerular filtration rate decreased [0.7-0.1 mL min(-1) g(-1) kidney weight (KW)] with elevated IAP, as did urine output (8.5-0.6 microL min(-1) g(-1) KW). Dramatic decreases were seen in renal excretion of sodium (by 97%), potassium (by 94%) and osmotic active substances (by 93%). Cardiac output was diminished by 54% at 5 mmHg and by 65% at 10 mmHg intraperitoneal pressure and systemic vascular resistance (SVR) was elevated threefold.

CONCLUSION

Cardiac output, measured by microsphere technique, decreased during elevated intraperitoneal pressure by CO2 in anaesthetized rats, while SVR was elevated and renal excretory functions were decreased to a large extent.