Intraabdominal microdialysis – methodological challenges

Abstract

Microdialysis is used for in vivo sampling of extracellular molecules. The technique provides a continuous and dynamic view of concentrations of both endogenous released and exogenous administered substances. Microdialysis carries a low risk of complications and has proven to be a safe procedure in humans. The technique has been applied in several clinical areas, including gastrointestinal surgery. Microdialysis may be used for studies of tissue metabolism, and the technique is also a promising tool for pharmacological studies of drug penetration into abdominal organ tissue and the peritoneal cavity. The clinical significance of intraabdominal microdialysis in postoperative monitoring of surgical patients has yet to be proven. In this review, we introduce the microdialysis technique, and we present an overview of theoretical and practical considerations that should be taken into account when using microdialysis in intraabdominal clinical research.

Perioperative intraperitoneal metabolic markers in patients undergoing cardiac surgery with cardiopulmonary bypass: an exploratory pilot study

“…Glycerol is derived from lipolysis or the breakdown of phospholipids, for example, in cell membranes, and is considered a marker of tissue hypoxia and/or energy depletion. 25 The subcutaneous glycerol concentrations were numerically much higher than the intraperitoneal concentrations, which corresponds to findings in abdominal surgery and may be explained by the accumulation of glycerol in adipose tissue. 25,26 The intraperitoneal glycerol concentration was unchanged throughout the perioperative course, which is not surprising since the included patients were free from complications.…”

“…25 The subcutaneous glycerol concentrations were numerically much higher than the intraperitoneal concentrations, which corresponds to findings in abdominal surgery and may be explained by the accumulation of glycerol in adipose tissue. 25,26 The intraperitoneal glycerol concentration was unchanged throughout the perioperative course, which is not surprising since the included patients were free from complications. This finding indicates that the intra-abdominal organs were not severely ischaemic and only reversibly put at risk for damage.…”

“…17 Complete ischaemia leads to intraperitoneal glucose concentrations close to zero and increased intraperitoneal glycerol concentrations. 25 In the present study, the intraperitoneal glucose concentrations increased postoperatively and reflected the arterial concentrations. However, intraoperatively, the intraperitoneal and subcutaneous glucose concentrations were numerically lower than the arterial values, which may be interpreted as a combination of stimulation of glycogenolysis and splanchnic hypoperfusion produced by catecholamines.…”

“…5,23,24 In parallel with the peak in lactate, the intraperitoneal lactate/pyruvate ratio peaked at 33.4, which is considered to be an even more sensitive measure of the relation between aerobic and anaerobic metabolism than the lactate concentration, since lactate is generated from pyruvate under anaerobic conditions. 13,25 Lactate/pyruvate ratios have been shown to increase dramatically in patients developing anastomotic leakage after abdominal surgery. 16 The lactate/pyruvate ratio increased even though pyruvate levels also increased, which is most likely an effect of the increased glucose levels available for metabolism.…”

Intraperitoneal microdialysis detects intestinal leakage earlier than hemodynamic surveillance and systemic inflammation in a pig model

“…However, arterial and hepatic lactate remained low throughout the experiment, and ischemic hyperlactatemia was thus not present, and we consider a severe hypoperfusion unlikely. The use of a high cut-off (100 kDa)-, rather than a 20 kDa-catheter could result in a loss of perfusion fluid and dilution of the sampled metabolites [36], however, we have shown that this can be prevented by using a colloidal perfusion fluid applied in this study [37]. Because of the experimental time frame of 10 h our study lacks information about the later postoperative course.…”