Intestinal histopathological changes in a porcine model of pneumoperitoneum-induced intra-abdominal hypertension

Thawed Porcine Model for Surgical Training: A Novel Conservative Procedure

Background: General Surgery course is a mandatory in medical schools and continuing surgery training is important even to experienced surgeons which they need to maintain and/or improve their surgical skills. Additionally, the models used for that practice are human cadavers, anesthetized porcine, or simulators and are not accessible for medicine schools or physicians in many countries. Therefore, we present a new technical procedure for preparation of frozen experimental animal's cadavers for medical surgical training. Materials and Methods: To perform the study, one porcine slaughtered and frozen at -20°C was used. The porcine cadaver was thawed at room temperature (25°C) and then the pneumoperitoneum test was performed and viscera inspection carried out. Results: The porcine cadaver took 20 hours to completely thaw. The pneumoperitoneum was successfully performed with total distention of the abdominal cavity. All viscera were well preserved maintaining important in vivo characteristics for consistency. Conclusion: The use of thawed porcine cadaver as a model to train many surgical procedures including videolaparoscopy is feasible. The tissues were well preserved by this method and was financially accessible and could be used for different techniques, equipment, and material tests.

Impact of intraabdominal hypertension on kidney failure in critically ill patients: A post-hoc database analysis

PURPOSE

To assess whether intraabdominal hypertension (IAH) may influence kidney failure as well as mortality.

METHODS

This post-hoc analysis of two databases (IROI and iSOFA study) tested the independent association between IAH and kidney failure. Mortality was assessed using four prespecified groups (IAH present, kidney failure present, IAH and kidney failure present and no IAH or kidney failure present).

RESULTS

Of 825 critically ill patients, 302 (36.6%) developed kidney failure and 192 (23.7%) died during the first 90 days. Only 'Cumulative days with IAH grade II or more' was significantly associated with kidney failure (OR 1.29 (1.08-1.55), p = 0.003) while 'cumulative days with IAH grade I or more' (p = 0.135) or highest daily IAP (p = 0.062) was not. IAH combined with kidney failure was independently associated with 90-day mortality (OR 2.20 (1.20-4.05), p = 0.011), which was confirmed for higher grades of IAH (grade II or more) alone (OR 2.14 (1.07-4.30), p = 0.032) and combined with kidney failure (OR 3.25 (1.72-6.12), p < 0.001).

CONCLUSIONS

This study suggest that duration as well as higher grades of IAH are associated with kidney failure and may increase mortality.

Post-Cardiac Arrest Syndrome Is Not Associated with An Early Bacterial Translocation

BACKGROUND

The aim of this study was to investigate bacterial translocation and its possible role in the development of post-resuscitation inflammatory response following Cardio-Pulmonary Resuscitation (CPR) after cardiac arrest.

METHODS

Munich female swine were employed for a model of cardiac arrest via application of electrical current. After 7 min, CPR was initiated, and animals were either successfully return to spontaneous circulation (ROSC) within 40 min or not (no-ROSC). At the end of experimental period and prior to sacrifice, samples from the intestine, mesenteric lymph nodes (MLN), liver and portal vein blood were obtained. Evaluation of inflammation and gut permeability was performed; MLN, liver and portal vein samples were analyzed for 16 s rRNA detection and cytokine mRNA expression.

RESULTS

A decreased expression of the tight junction protein Occludin, with higher levels of inflammation, greater epithelial disintegration, ulceration, loss of crypts and villi height were found in the intestines of the ROSC swine in comparison to no-ROSC. The macrophage surface antigen CD-14 staining was relatively more intense in the ROSC than in no-ROSC. Higher levels of TNF-α mRNA expression were present in the liver of the ROSC group. Finally, despite the inflammatory response and the gut mucosal alterations in ROSC group, no bacterial translocation was detected in liver, MLN and portal vein.

CONCLUSIONS

We show that resuscitation from cardiac arrest induces inflammatory response and intestinal permeability in swine 4h after resuscitation, but not a bacterial translocation. Bacterial translocation is not an early phase phenomenon but probably part of the pathophysiologic sequelae.

Relationship between Gastric pH Measurement and Intra-abdominal Pressure in Patients Undergoing Laparoscopic Surgery

Objectives:

Laparoscopic surgery (LS) is a safe and widely used technique. During LS, carbon dioxide insufflation may produce significant hemodynamic and ventilatory consequences, such as elevated intra-abdominal pressure (IAP) and hypercarbia. Splanchnic and cardiovascular blood flow can be affected by the elevated IAP, which can result in ischemia in the splanchnic region prior to hemodynamic changes. Changes in gastric pH may be an early precursor of changes in splanchnic blood circulation. This study investigated the relationship between gastric pH measurement and IAP in patients undergoing LS.

Methods:

This study included 49 patients aged 18–65 years with American Society of Anesthesiologists (ASA) physical status I – III who were undergoing elective laparoscopic cholecystectomy. A gastric pH tonometer probe was applied using an orogastric catheter. Simultaneously, insufflation pressure, cardiac apex beat (CAB), and mean arterial blood pressure (MAP) values were recorded. Indirect IAP was then measured through the bladder. Measurements were performed at baseline; at 15, 30, and 60 minutes after onset of insufflation (AI 15, AI 30, and AI 60, respectively); and at the end of insufflation (EI). Two pH measurements were obtained with a gastric tonometer pH probe, using an automated function of the gastric tonometer to improve measurement reliability.

Results:

IAP was significantly higher than baseline at AI 15, AI 30, AI 60, and EI (p<0.001). The pH₁ and pH₂ levels were significantly lower at AI 15 and AI 30, compared with baseline (p<0.001). There were no significant differences between pH₁ and pH₂ measurements at AI 60 and EI. Compared with baseline, CAB was significantly lower at AI 15, AI 30, AI 60, and EI (p=0.001, p<0.001, p=0.006). There were no statistically significant differences in MAP changes at any time point.

Conclusion:

Elevated IAP caused by CO₂ insufflation during LS led to reductions of pH₁ and pH₂. There was a correlation between gastric pH measurement and IAP. Measurement of gastric pH may be useful to assess blood circulation in the splenic area during LS.

Effects of Pneumoperitoneum on Splanchnic Oxygenation during Abdominal Laparoscopic Surgery in Paediatric Patients: A prospective, Observational Study

Objective

Pneumoperitoneum can cause disruption in splanchnic perfusion. This study aims to investigate effects of pneumoperitoneum on splanchnic oxygenation during abdominal laparoscopic surgery in paediatric patients with NIRS (Near-Infrared Spectroscopy).

Material and methods

A total of 45 patients between 1 and 4 years of age with ASA physical status I–II and scheduled to undergo abdominal laparoscopic surgery under general anaesthesia were enrolled in this prospective, observational surgery. No premedication was used. Standard monitoring and regional splanchnic saturation (rSPcO₂), regional cerebral oxygen saturation (rScO₂) with NIRS were established before anaesthesia. Anaesthesia was induced with an inhalational agent and maintained with an oxygen/air mixture and sevoflurane. Peripheral oxygen saturation (SPO₂), rSPcO₂, rScO₂, heart rate (HR), mean arterial pressure (MAP), end tidal CO₂ (Et-CO₂), and insufflation pressure (IP) were continuously monitored during administration of anaesthesia and recorded. After intubation (baseline T0); before CO₂ insufflation induced pneumoperitoneum (PP) (T1); CO₂ PP insufflation (T2); 5 minutes after PP insufflation (T3); 10 minutes after PP insufflation (T4); 15 minutes after PP insufflation (T5); 20 minutes after PP insufflation (T6); 30 minutes after PP insufflation (T7), 60 minutes after PP insufflation (T8), and after desufflation (T9). Bradycardia and hypotension were recorded. Paracetamol IV 10 mg kg⁻¹ was applied for post-operative analgesia. p<0.05 wasconsidered significant.

Results

HR, rScO₂, and rSPcO₂ decreased at all measured time intervals when compared to T0 (p<0.01) MAP decreased at T1 compared to T0 (p<0.001). Et-CO₂ increased at T3-T4-T5-T6 compared to T0 (p<0.001).

Conclusion

We found that pneumoperitoneum reduced splanchnic oxygenation during laparoscopic abdominal surgery in paediatric patients, which was measured using NIRS.

Impact of pneumoperitoneum on intra-abdominal microcirculation blood flow: an experimental randomized controlled study of two insufflator models during transanal total mesorectal excision : An experimental randomized multi-arm trial with parallel treatment design

OBJECTIVE

To compare changes in microcirculation blood flow (MCBF) between pulsatile and continuous flow insufflation. Transanal total mesorectal excision (TaTME) was developed to improve the quality of the resection in rectal cancer surgery. The AirSeal IFS® insufflator facilitates the pelvic dissection, although evidence on the effects that continuous flow insufflation has on MCBF is scarce.

METHODS

Thirty-two pigs were randomly assigned to undergo a two-team TaTME procedure with continuous (n = 16) or pulsatile insufflation (n = 16). Each group was stratified according to two different pressure levels in both the abdominal and the transanal fields, 10 mmHg or 14 mmHg. A generalized estimating equations (GEE) model was used.

RESULTS

At an intra-abdominal pressure (IAP) of 10 mmHg, continuous insufflation was associated with a significantly lower MCBF reduction in colon mucosa [13% (IQR 11;14) vs. 21% (IQR 17;24) at 60 min], colon serosa [14% (IQR 9.2;18) vs. 25% (IQR 22;30) at 60 min], jejunal mucosa [13% (IQR 11;14) vs. 20% (IQR 20;22) at 60 min], renal cortex [18% (IQR 15;20) vs. 26% (IQR 26;29) at 60 min], and renal medulla [15% (IQR 11;20) vs. 20% (IQR 19;21) at 90 min]. At an IAP of 14 mmHg, MCBF in colon mucosa decreased 23% (IQR 14;27) in the continuous group and 28% (IQR 26;31) in the pulsatile group (p = 0.034).

CONCLUSION

TaTME using continuous flow insufflation was associated with a lower MCBF reduction in colon mucosa and serosa, jejunal mucosa, renal cortex, and renal medulla compared to pulsatile insufflation.

Intra-abdominal pressure during endoscopic full-thickness resection comparing manual and automatic control insufflation: a block-randomized porcine study

BACKGROUND AND STUDY AIMS

An automatic carbon dioxide (CO2) insufflating system (SPACE) was developed to stabilize intra-lumenal pressure (ILP) during endoscopic interventions. This study investigated whether SPACE could improve the control and monitoring of extra-lumenal intra-abdominal pressure (IAP) after establishing a perforation during endoscopic full-thickness resection (EFTR) of the gastric wall in porcine models.

MATERIALS AND METHODS

After first establishing the optimal preset pressure for gastric EFTR in four pigs, we compared IAP dynamics during EFTR between manual insufflation and SPACE using a block-randomized study (n = 10). IAP was percutaneously monitored and plotted on a timeline graph every 5 s. The maximal IAP and the area under the IAP curve exceeding 10 mmHg (AUC≥10 mmHg) were compared between groups, with the agreement between IAP and endolumenally monitored ILP also analyzed for animals in the SPACE group.

RESULTS

In the first study, 8 mmHg was identified as the most preferable preset pressure after establishment of the perforation. In the randomized study, the mean maximal IAP in the SPACE group was significantly lower than that in the manual insufflation group (11.0 ± 2.0 mmHg vs. 17.0 ± 3.5 mmHg; P = 0.03). The mean AUC≥10 mmHg was also significantly smaller in the SPACE group. Bland-Altman analysis demonstrated agreement between IAP and ILP within a range of ± 1.0 mmHg.

CONCLUSIONS

SPACE could be used to control and safely monitor IAP during gastric EFTR by measuring ILP during perforation of the gastric wall.