Intraperitoneal microdialysis in the postoperative surveillance after surgery for necrotizing enterocolitis: a preliminary report

Early detection of anastomotic leakage after pancreatoduodenectomy with microdialysis catheters: an observational Study

BACKGROUND

Microdialysis catheters can detect focal inflammation and ischemia, and thereby have a potential for early detection of anastomotic leakages after pancreatoduodenectomy. The aim was to investigate whether microdialysis catheters placed near the pancreaticojejunostomy can detect leakage earlier than the current standard of care.

METHODS

Thirty-five patients with a median age 69 years were included. Two microdialysis catheters were placed at the end of surgery; one at the pancreaticojejunostomy, and one at the hepaticojejunostomy. Concentrations of glucose, lactate, pyruvate, and glycerol were analyzed hourly in the microdialysate during the first 24 h, and every 2-4 h thereafter.

RESULTS

Seven patients with postoperative pancreatic fistulae (POPF) had significantly higher glycerol levels (P < 0.01) in the microdialysate already in the first postoperative samples. Glycerol concentrations >400 μmol/L during the first 12 postoperative hours detected patients with POPF with a sensitivity of 100% and a specificity of 93% (P < 0.001). After 24 h, lactate and lactate-to-pyruvate ratio were significantly higher (P < 0.05) and glucose was significantly lower (P < 0.05) in patients with POPF.

CONCLUSION

High levels of glycerol in microdialysate was an early detector of POPF. The subsequent inflammation was detected as increase in lactate and lactate-to-pyruvate ratio and a decrease in glucose (NCT03627559).

A scoping review of pediatric microdialysis: A missed opportunity for microdialysis in the pediatric neuro-oncology setting

Background

Brain microdialysis is a minimally invasive technique for monitoring analytes, metabolites, drugs, neurotransmitters, and/or cytokines. Studies to date have centered on adults with traumatic brain injury, with a limited number of pediatric studies performed. This scoping review details past use of brain microdialysis in children and identifies potential use for future neuro-oncology trials.

Methods

In December 2020, Cochrane Library: CENTRAL, Embase, PubMed, Scopus, and Web of Science: Core Collection were searched. Two reviewers screened all articles by title and abstract review and then full study texts, using microdialysis in patients less than 18 yo.

Results

Of the 1171 articles screened, 49 were included. The 49 studies included 472 pediatric patients (age range 0–17 years old), in the brain (21), abdominal (16), and musculoskeletal (12) regions. Intracerebral microdialysis was performed in 64 collective patients, with a median age of 11 years old, and predominance in metabolic evaluations.

Conclusion

Historically, pediatric microdialysis was safely performed within the brain in varied neurologic conditions, except neuro-oncology. Adult brain tumor studies using intratumoral/peritumoral microdialysis sampling can inform future pediatric studies to advance diagnosis and treatment options for such aggressive tumors.

Microdialysis sampling to monitor target-site vancomycin concentrations in septic infants: a feasible way to close the knowledge gap

This work is dedicated to the memory of Hartmut Derendorf (1953-2020), a pioneer of modern pharmacokinetics and valued mentor of this project.

OBJECTIVES

Septic infants/neonates need effective antibiotic exposure, but dosing recommendations are challenging as the pharmacokinetics in this age are highly variable. For vancomycin, which is used as a standard treatment, comprehensive pharmacokinetic knowledge especially at the infection site is lacking. Hence, an exploratory clinical study was conducted to assess the feasibility and safety of microdialysis sampling for vancomycin monitoring at the target site.

METHODS

Nine infants/neonates with therapeutic indications for vancomycin treatment were administered 15 mg/kg as 1-hour infusions every 8-24 hours. Microdialysis catheters were implanted in the subcutaneous interstitial space fluid of the lateral thigh. Samples were collected every 30 minutes over 24 hours, followed by retrodialysis for catheter calibration. Prior in vitro investigations have evaluated impact factors on relative recovery and retrodialysis.

RESULTS

In vitro investigations showed the applicability of microdialysis for vancomycin monitoring. Microdialysis sampling was well tolerated in all infants/neonates (23-255 days) without major bleeding or other adverse events. Pharmacokinetic profiles were obtained and showed plausible vancomycin concentration-time courses.

CONCLUSIONS

Microdialysis as a minimally invasive technique for continuous longer-term sampling is feasible and safe in infants/neonates. Interstitial space fluid profiles were plausible and showed substantial interpatient variation. Hence, a larger microdialysis trial is warranted to further characterise the pharmacokinetics and variability of vancomycin at the target site and ultimately improve vancomycin dosing in these vulnerable patients.

Monitoring of patients with microdialysis following pancreaticoduodenectomy-the MINIMUM study: study protocol for a randomized controlled trial

BACKGROUND

Postoperative pancreatic fistula after pancreatoduodenectomy is a much-feared complication associated with substantial mortality and morbidity. The current standard for diagnosing postoperative pancreatic fistula, besides routine clinical examination, include radiological examinations, analysis of pancreatic drain amylase activity, and routine blood samples. Another promising method is by intraperitoneal microdialysis to monitor intraperitoneal metabolites measured at the pancreaticojejunostomy, thereby detecting what occurs locally, before chemical events can be reflected as measurable changes in systemic blood levels.

METHODS

The MINIMUM study is a prospective, randomized, controlled, single center enrolling 200 patients scheduled for open pancreatoduodenectomy comparing the microdialysis method to the "standard of care." Half of the included patients will be randomized to receive an intraperitoneal microdialysis catheter implanted at the end of surgery and will be monitored by microdialysis as an additional monitoring tool. The other half of the patients will not receive a microdialysis catheter and will be monitored according to the current standard of care. The primary objective is to evaluate if the microdialysis method can reduce the total length of stay at the hospital. Secondary endpoints are the frequency of complications, length of stay at the hospital at our institution, catheter malfunction, number of infections and bleeding episodes caused by the microdialysis catheter, patient-reported quality of life and pain, and cost per patient undergoing pancreatoduodenectomy. The patients will be randomized in a 1:1 ratio.

DISCUSSION

Intraabdominal microdialysis could potentially reduce morbidity and mortality after pancreatoduodenectomy. Furthermore, there is a great potential for shortening the in-hospital length of stay and reducing the financial aspect considerably. This study may potentially open the possibility for using microdialysis as standard monitoring in patients undergoing pancreatoduodenectomy. The hypothesis is that the microdialysis method compared to "standard care" will reduce the total length of hospital stay.

TRIAL REGISTRATION

Clinicaltrials.gov ( NCT03631173 ). Registered on 7 September 2018 under the name: "Monitoring of patients With Microdialysis Following Pancreaticoduodenectomy". Based on protocol version 19-1, dated 15th January 2019.

Microdialysis in Postoperative Monitoring of Gastrointestinal Organ Viability: A Systematic Review

BACKGROUND

Microdialysis is a technique for continuous measurement of extracellular substances. It may be used to monitor tissue viability. The clinical implications of using microdialysis as a tool in gastrointestinal surgery have yet to be defined. The aim of the present study was to evaluate the clinical significance of microdialysis with special attention to different markers measured to predict the clinical outcome of surgical patients.

METHODS

Embase, MEDLINE, and the Cochrane Library were searched systematically for human studies written in English. Study selection, data extraction, and quality assessment were performed independently by two authors. We included studies in which the microdialysis technique was used for postoperative monitoring of patients undergoing gastrointestinal surgery. To be eligible, studies had to compare patients with and without postoperative complications.

RESULTS

Twenty-six studies were included in this review. MINORS score ranged from 3 to 12 (median 10.5). Most studies showed that levels of biomarkers obtained by microdialysis correlated with the postoperative clinical course. Lactate, pyruvate, glucose, and glycerol were the most frequently measured biomarkers. Several studies found that changes in biomarkers in complicated patients preceded symptoms of complications and/or changes in conventional paraclinical methods of postoperative monitoring.

CONCLUSIONS

Studies show that microdialysis may have the potential to become a tool in postoperative surveillance of surgical patients. Larger randomized studies are needed to define the clinical implications of microdialysis.

Critical evaluation of colon submucosal microdialysis in awake, mobile rats

Sensors able to record large bowel physiology and biochemistry in situ in awake rodents are lacking. Microdialysis is a mini-invasive technique that may be utilized to continuously deliver or recover low-molecular substances from various tissues. In this experiment we evaluated the feasibility of in vivo microdialysis to monitor extracellular fluid chemistry in the descending colon submucosa of conscious, freely moving rodents. Following surgical implantation of a microdialysis probe, male Wistar rats were housed in metabolic cages where they were analgized and clinically followed for four days with free access to standard diet and water. To assess local microcirculation and probe function, glucose, lactate, glucose-to-lactate ratio and urea clearance were determined in the dialysates from the three postoperative days with focus on the final 24-h period. In an attempt to mitigate the expected tissue inflammatory response, one group of animals had the catheters perfused with 5-aminosalicylic acid-enriched medium with final concentration 1 μmol/L. For verification of probe position and the assessment of the surrounding foreign body reaction, standard histological and immunohistochemical methods were employed. Microdialysis of rat gut is associated with considerable technical challenges that may lead to the loss of probe function and high drop-out rate. In this setting, limited data did not allow to draw any firm conclusion regarding local anti-inflammatory effectiveness of 5-aminosalicylic acid perfusion. Although intestinal microdialysis may be suitable for larger anesthetized animals, low reproducibility of the presented method compromises its routine experimental use in awake and freely moving small-sized rodents.

Intraperitoneal lactate/pyruvate ratio and the level of glucose and glycerol concentration differ between patients surgically treated for upper and lower perforations of the gastrointestinal tract: a pilot study

BACKGROUND

Secondary peritonitis is a condition associated with high morbidity and mortality. Continuous postoperative monitoring of patients to ensure timely intervention to treat complications without delay is important for survival and outcome. We aimed to (1) investigate potential differences in postoperative intraperitoneal biomarker levels between patients with upper and lower gastrointestinal tract lesion, and (2) compare postoperative biomarker levels between complicated and uncomplicated patients.

METHODS

We included a total of 15 consecutive patients operated for upper (n = 7) and lower (n = 8) gastrointestinal tract perforation. We registered postoperative complications during a 30 days follow up-period. Complications were defined as intraabdominal complications, septic shock, and mortality. 5 patients were complicated. A microdialysis catheter was placed intraperitoneally in each patient. Samples were collected every 4th hour for up to 7 postoperative days. Samples were analysed for concentrations of glucose, lactate, pyruvate and glycerol.

RESULTS

Microdialysis results showed that patients with upper gastrointestinal tract lesions had significantly higher levels of postoperative intraperitoneal glucose and glycerol concentrations, as well as lower lactate/pyruvate ratios and lactate/glucose ratios. In the group with perforation of the lower gastrointestinal tract, those patients with a complicated course showed lower levels of postoperative intraperitoneal glucose concentration and glycerol concentration and higher lactate/pyruvate ratios and lactate/glucose ratios than those patients with an uncomplicated course.

CONCLUSION

Patients with upper and lower gastrointestinal tract lesions showed differences in postoperative biomarker levels. A difference was also seen between patients with complicated and uncomplicated postoperative courses.

Intraperitoneal microdialysis as a monitoring method in the intensive care unit

Studies on surgical patients provide some evidence of prompt detection of enteric ischemia with microdialysis. The purpose of the study was to measure intraperitoneal microdialysis values (glucose, glycerol, pyruvate, and lactate) in patients hospitalized in an intensive care unit (ICU) with an underlying abdominal surgical condition and to correlate these values with patients' outcomes. Twenty-one patients, 10 female, were enrolled in the study. The intraperitoneal metabolite values were measured for 3 consecutive days, starting from the first day of ICU hospitalization. Descriptive and inferential statistics were performed. The t-test, repeated measures analysis, Holm's test, and a logistic regression model were applied. Level of statistical significance was set at P = 0.05. Mean age of participants was 68.10 ± 8.02 years old. Survivors exhibited statistically significantly higher glucose values on day 3 (6.61 ± 2.01 against 3.67 ± 1.62; P = 0.002). Mean lactate/ pyruvate (L/P) values were above 20 (35.35 ± 27.11). All non-survivors had a mean three day L/P values greater than 25.94. Low L/P values were related to increased survival possibilities. High microdialysis glucose concentration, high L/P ratio and low glucose concentration were the major findings during the first three ICU hospitalization days in non-survivors. Intraperitoneal microdialysis may serve as a useful tool in understanding enteric ischemia pathophysiology.

Intraperitoneal microdialysis in the postoperative surveillance of infants undergoing surgery for congenital abdominal wall defect: A pilot study

PURPOSE

This study aims to investigate the safety and clinical implication of intraperitoneal microdialysis (MD) in newborns operated on for congenital abdominal wall defect.

PATIENTS AND METHODS

13 infants underwent intraperitoneal microdialysis (9 with gastroschisis and 4 with omphalocele). MD samples were collected every four hours and the concentrations of lactate, glycerol, glucose and pyruvate were measured. The results of MD were compared between the group of infants with gastroschisis and the group with omphalocele. The duration of parenteral nutrition and tube feeding were compared for high and low levels of intraperitoneal lactate, glycerol, and glucose and lactate/pyruvate ratio respectively. High and low levels were defined as above or below the median value on day one.

RESULTS

Results from intraperitoneal MD showed a significantly higher mean lactate concentration in the group of infants with gastroschisis compared with the group of infants with omphalocele. The median values were 6.19 mmol/l and 2.19 mmol/l, respectively (P=0.006). The results from MD in the six infants in the gastroschisis group who underwent secondary closure after Silo treatment were similar to those who underwent primary closure. None of the infants with omphalocele received parenteral nutrition whereas all of the infants with gastroschisis did. There was no significant difference in duration of parenteral nutrition or tube feeding, respectively, when comparing the gastroschisis children with high versus low intraperitoneal lactate values. Placement of the MD catheter in the intraperitoneal cavity was feasible and without any major complications.

CONCLUSION

Intraperitoneal MD is a safe procedure and an applicable method in surveillance of inflammatory changes in the peritoneal cavity in infants after operation for congenital abdominal wall defect. The true clinical value in infants with congenital wall defect remains unknown.

Clinical experience with microdialysis catheters in pediatric liver transplants

Ischemic vascular complications and rejection occur more frequently with pediatric liver transplants versus adult liver transplants. Using intrahepatic microdialysis catheters, we measured lactate, pyruvate, glucose, and glycerol values at the bedside for a median of 10 days in 20 pediatric liver grafts. Ischemia (n = 6), which was defined as a lactate level > 3.0 mM and a lactate/pyruvate ratio > 20, was detected without a measurable time delay with 100% sensitivity and 86% specificity. Rejection (n = 8), which was defined as a lactate level > 2.0 mM and a lactate/pyruvate ratio < 20 lasting for 6 or more hours, was detected with 88% sensitivity and 45% specificity. With additional clinical criteria, the specificity was 83% without a decrease in the sensitivity. Rejection was detected at a median of 4 days (range = 1-7 days) before alanine aminotransferase increased (n = 5, P = 0.11), at a median of 4 days (range = 2-9 days) before total bilirubin increased 25% or more (n = 7, P = 0.04), and at a median of 6 days (range = 4-11 days) before biopsy was performed (n = 8, P = 0.05). In conclusion, microdialysis catheters can be used to detect episodes of ischemia and rejection before current standard methods in pediatric liver transplants with clinically acceptable levels of sensitivity and specificity. The catheters were well tolerated by the children, and no major complications related to the catheters were observed.

Early bedside detection of ischemia and rejection in liver transplants by microdialysis

This study was performed to explore whether lactate, pyruvate, glucose, and glycerol levels sampled via microdialysis catheters in the transplanted liver could be used to detect ischemia and/or rejection. The metabolites were measured at the bedside every 1 to 2 hours after the operation for a median of 10 days. Twelve grafts with biopsy-proven rejection and 9 grafts with ischemia were compared to a reference group of 39 grafts with uneventful courses. The median lactate level was significantly higher in both the ischemia group [5.8 mM (interquartile range = 4.0-11.1 mM)] and the rejection group [2.1 mM (interquartile range = 1.9-2.4 mM)] versus the reference group [1.5 mM (interquartile range = 1.1-1.9 mM), P < 0.001 for both]. The median pyruvate level was significantly increased only in the rejection group [185 μM (interquartile range = 155-206 μM)] versus the reference group [124 μM (interquartile range = 102-150 μM), P < 0.001], whereas the median lactate/pyruvate ratio and the median glycerol level were increased only in the ischemia group [66.1 (interquartile range = 23.9-156.7) and 138 μM (interquartile range = 26-260 μM)] versus the reference group [11.8 (interquartile range = 10.6-13.6), P < 0.001, and 9 μM (interquartile range = 9-24 μM), P = 0.002]. Ischemia was detected with 100% sensitivity and greater than 90% specificity when a positive test was repeated after 1 hour. In 3 cases of hepatic artery thrombosis, ischemia was detected despite normal blood lactate levels. Consecutive pathological measurements for 6 hours were used to diagnose rejection with greater than 80% sensitivity and specificity at a median of 4 days before the activity of alanine aminotransferase, the concentration of bilirubin in serum, or both increased. In conclusion, bedside measurements of intrahepatic lactate and pyruvate levels were used to detect ischemia and rejection earlier than current standard methods could. Discrimination from an uneventful patient course was achieved. Consequently, intrahepatic graft monitoring with microdialysis may lead to the earlier initiation of graft-saving treatment.