Small-bowel capsule endoscopy and device-assisted enteroscopy for diagnosis and treatment of small-bowel disorders: European Society of Gastrointestinal Endoscopy (ESGE) Guideline - Update 2022.

MR1: ESGE recommends small-bowel capsule endoscopy as the first-line examination, before consideration of other endoscopic and radiological diagnostic tests for suspected small-bowel bleeding, given the excellent safety profile of capsule endoscopy, its patient tolerability, and its potential to visualize the entire small-bowel mucosa.Strong recommendation, moderate quality evidence. MR2: ESGE recommends small-bowel capsule endoscopy in patients with overt suspected small-bowel bleeding as soon as possible after the bleeding episode, ideally within 48 hours, to maximize the diagnostic and subsequent therapeutic yield.Strong recommendation, high quality evidence. MR3: ESGE does not recommend routine second-look endoscopy prior to small-bowel capsule endoscopy in patients with suspected small-bowel bleeding or iron-deficiency anemia.Strong recommendation, low quality evidence. MR4: ESGE recommends conservative management in those patients with suspected small-bowel bleeding and high quality negative small-bowel capsule endoscopy.Strong recommendation, moderate quality evidence. MR5: ESGE recommends device-assisted enteroscopy to confirm and possibly treat lesions identified by small-bowel capsule endoscopy.Strong recommendation, high quality evidence. MR6: ESGE recommends the performance of small-bowel capsule endoscopy as a first-line examination in patients with iron-deficiency anemia when small bowel evaluation is indicated.Strong recommendation, high quality evidence. MR7: ESGE recommends small-bowel capsule endoscopy in patients with suspected Crohn's disease and negative ileocolonoscopy findings as the initial diagnostic modality for investigating the small bowel, in the absence of obstructive symptoms or known bowel stenosis.Strong recommendation, high quality evidence. MR8: ESGE recommends, in patients with unremarkable or nondiagnostic findings from dedicated small-bowel cross-sectional imaging, small-bowel capsule endoscopy as a subsequent investigation if deemed likely to influence patient management.Strong recommendation, low quality evidence. MR9: ESGE recommends, in patients with established Crohn's disease, the use of a patency capsule before small-bowel capsule endoscopy to decrease the capsule retention rate.Strong recommendation, moderate quality evidence. MR10: ESGE recommends device-assisted enteroscopy (DAE) as an alternative to surgery for foreign bodies retained in the small bowel requiring retrieval in patients without acute intestinal obstruction.Strong recommendation, moderate quality evidence. MR11: ESGE recommends DAE-endoscopic retrograde cholangiopancreatography (DAE-ERCP) as a first-line endoscopic approach to treat pancreaticobiliary diseases in patients with surgically altered anatomy (except for Billroth II patients).Strong recommendation, moderate quality evidence.

News in gastroenterology, hepatology and digestive endoscopy.

Gastroenterology, hepatology and digestive endoscopy are rapidly evolving disciplines with significant advances in the diagnostics and treatment in the entire gastrointestinal tract. The aim of our article was to summarize new perspectives on relevant situations in gastroenterology and hepatology like acute pancreatitis, functional dyspepsia, rational indication of proton pump inhibitors, inflammatory bowel diseases (IBD), cholestatic liver diseases, alcohol induced hepatitis, non-alcoholic fatty live disease (NAFLD) and patophysiology of bilirubin and bile acids. Digestive endoscopy represents an interventional part of gastroenterology and key recent topics are mentioned like pancreatic cancer screening, arteficial intelligence, resection of low-risk neoplastic lesions, enteroscopy techniques, cholangio- and pancreatiscopy and extraluminal expansion of endoscopy techniques by means of endoscopic submucosal and transmural dissection, endoscopic myotomy and lumen apposing stents.

Expression profiles of iron transport molecules along the duodenum.

Duodenal biopsies are considered a suitable source of enterocytes for studies of dietary iron absorption. However, the expression level of molecules involved in iron absorption may vary along the length of duodenum. We aimed to determine whether the expression of molecules involved in the absorption of heme and non-heme iron differs depending on the location in the duodenum. Analysis was performed with samples of duodenal biopsies from 10 individuals with normal iron metabolism. Samples were collected at the following locations: (a) immediately post-bulbar, (b) 1-2 cm below the papilla of Vater and (c) in the distal duodenum. The gene expression was analyzed at the mRNA and protein level using real-time PCR and Western blot analysis. At the mRNA level, significantly different expression of HCP1, DMT1, ferroportin and Zip8 was found at individual positions of duodenum. Position-dependent expression of other molecules, especially of FLVCR1, HMOX1 and HMOX2 was also detected but with no statistical significances. At the protein level, we observed statistically significantly decreasing expression of transporters HCP1, FLVCR1, DMT1, ferroportin, Zip14 and Zip8 with advancing positions of duodenum. Our results are consistent with a gradient of diminishing iron absorption along the duodenum for both heme and non-heme iron.

Antithrombotic therapy and digestive endoscopy.

Antithrombotic therapy and digestive endoscopy Antithrombotic therapy comprises anticoagulation and antiplatelet treatment. The number of patients treated with various forms of antithrombotic therapy is growing. Procedures of digestive endoscopy are very frequently indicated by general practitioners and doctors of various specialisations. Interdisciplinary cooperation and mutual understanding are required in order for digestive endoscopy to be effective and safe. Hence, we present an overview based on recent European, British (1), and North American guidelines (2) for endoscopic procedures, with respect to guidelines for perioperative care in general (3). Antithrombotic therapy management in patients undergoing digestive endoscopy procedures is based on individual consideration of postprocedural bleeding (particularly a delayed one) on one hand, and thromboembolic risk on the other hand, ideally in cooperation with the physician prescribing antithrombotic therapy. Despite all efforts, patients taking antithrombotic medication are at a higher risk of postprocedural bleeding in comparison with those without this risk; this fact should be accepted by attending physicians and patients should be informed of it. Postprocedural bleeding is mostly manageable with a subsequent endoscopic procedure. By contrast, cerebral and cardiovascular thromboembolic complications are often life-threatening and not uncommonly disabling. One should always consider postponing an elective procedure in a patient with temporary antithrombotic therapy (after pulmonary embolism or after coronary stent insertion). Basic principles of administration of antithrombotic therapy in the context of an endoscopic procedure are described in Table 1. Digestive endoscopy procedures can be categorized according to postprocedural bleeding risk (Table 2). Postprocedural bleeding risk can be specifically reduced in some procedures (ERCP with papillary balloon dilation instead of sphincterotomy, mechanical securing of polypectomy base, etc.). Acetylsalicylic acid administered as secondary prevention (primary preventive indications are very narrow nowadays) should not be discontinued perioperatively (discontinuation is associated with an approximately threefold increase in thrombotic complications!). The riskiest procedures are the only exception in which discontinuation is explicitly requested by the digestive endoscopist. Reduction of dual antiplatelet therapy is better abandoned in high-risk patients - particularly those with recently implanted coronary stents (Table 3) - and postponement of an elective procedure should always be considered. Bridging of warfarin with low-molecular-weight heparin (LMWH) is not indicated routinely (in some cases, this practice increases the bleeding risk). Bridging with LMWH is appropriate in patients with high (or moderate) thromboembolic risk (Table 5). Furthermore, LMWH therapy carries specific risks, particularly in patients with renal function impairment (Table 4). In patients with a high thromboembolic risk, a statement of the physician indicating anticoagulation is always appropriate before an elective procedure (Table 6). Direct oral anticoagulants (DOACs) should not be administered on the day of the procedure, not even in one with a low risk (e.g., biopsy); a longer withdrawal is recommended in high-risk procedures (this cessation should not be bridged with LMWH given the rapid onset and elimination half-time) (Table 7). Recommencement of antithrombotic therapy after a high-risk endoscopic procedure should always be determined by the endoscopist and the recommended intervals should be considered minimal: 1-2 days after the procedure in the case of P2Y12 inhibitors; 2-3 days after the procedure in the case of DOACs; in the evening of the day of the procedure for warfarin with a maintenance (not saturation) dose; and 48 hours after the procedure in the case of LMWH at a therapeutic dose. Earlier administration of a lower-than-therapeutic dose of LMWH (twice a day per weight) can be considered in this context: prophylactic (once a day) or higher prophylactic (once a day per weight) doses. In general, a full anticoagulation effect should not be achieved earlier than approximately 48 hours after the procedure. The patient should be properly informed of the course of antithrombotic therapy before and after the endoscopic procedure, including a written form (a calendar can be downloaded online for this purpose).

Early gastric cancer.

Early gastric cancer is defined histopathologically as a tumour with limited local progression to the mucosa and submucosa. The concept of early cancer was developed in the 1960s in Japan and is now widely accepted. The term of early gastric cancer included cases with/without metastatic lymph node involvement. However, a common characteristic is a favourable prognosis of the disease. The task of the endoscopist is primarily to diagnose (identify) the tumour (precancerous lesions) and to verify it by biopsy. Successful identification must be followed by its correct classification, leading to the choice of an adequate approach, which includes surveillance, endoscopic treatment (resection) or surgical treatment (with or without chemotherapy). The method of treatment is determined primarily by the nature or risk of lymph node involvement.

Peutz-Jeghers syndrome.

PURPOSE OF REVIEW: Peutz-Jeghers syndrome is a rare, autosomal dominant, hereditary polyposis syndrome defined by gastrointestinal hamartomas and mucocutaneous pigmentations, caused by a germline mutation in the serine/ threonine kinase 11 or liver kinase B1 (STK11/LKB1) genes. Hamartomatous polyps located throughout the gastrointestinal tract can be complicated by bleeding and small bowel intussusception, potentially leading to the need for emergency surgery. Individuals suffering from Peutz-Jeghers syndrome have an increased lifetime risk of various forms of cancer (gastrointestinal, pancreatic, lung, breast, uterine, ovarian and testicular). Surveillance should lead to the prevention of complications and thus a reduction in mortality and morbidity of patients. RECENT FINDINGS: A combined approach based on wireless capsule endoscopy, magnetic resonance enterography and device-assisted enteroscopy is effective in reduction of the polyp burden and thus decreasing the risk of bleeding and intussusception. Current guidelines for screening and surveillance are mostly based on expert opinion rather than evidence. SUMMARY: Peutz-Jeghers syndrome is an emerging disease that significantly affects the quality of life enjoyed by patients. Despite of all the progress in improved early diagnostics, options for advanced endoscopic therapy and elaborate surveillance, acute and chronic complications decrease the life expectancy of patients suffering from Peutz-Jeghers syndrome.

The Impact of Dextran Sodium Sulfate-Induced Gastrointestinal Injury on the Pharmacokinetic Parameters of Donepezil and Its Active Metabolite 6-O-desmethyldonepezil, and Gastric Myoelectric Activity in Experimental Pigs.

Gastrointestinal side effects of donepezil, including dyspepsia, nausea, vomiting or diarrhea, occur in 20-30% of patients. The pathogenesis of these dysmotility associated disorders has not been fully clarified yet. Pharmacokinetic parameters of donepezil and its active metabolite 6-O-desmethyldonepezil were investigated in experimental pigs with and without small intestinal injury induced by dextran sodium sulfate (DSS). Morphological features of this injury were evaluated by a video capsule endoscopy. The effect of a single and repeated doses of donepezil on gastric myoelectric activity was assessed. Both DSS-induced small intestinal injury and prolonged small intestinal transit time caused higher plasma concentrations of donepezil in experimental pigs. This has an important implication for clinical practice in humans, with a need to reduce doses of the drug if an underlying gastrointestinal disease is present. Donepezil had an undesirable impact on porcine myoelectric activity. This effect was further aggravated by DSS-induced small intestinal injury. These findings can explain donepezil-associated dyspepsia in humans.

Dieulafoys jejunal lesion as a source of lifethreating bleeding.

Dieulafoy`s lesion is a rare condition characterized by bleeding into gastrointestinal tract from minimaly eroded submucous artery. Mostly is localized in stomach in elderly polymorbid men, but can occure in entire gastrointestinal tract, in both sexes, in every age. It should be thought off as one of possible causes of obscure bleeding. It is often massive, requiring fast diagnostics, treatment and multidisciplinary approach. The case report discusses patient with recurrent hemodynamicaly significant bleeding into jejunum. It pointed to combined diagnostic approach using both endoscopy and angiography. After failing endoscopically and angiografically due to hemodynamic instability, surgical intervention took place. Precise Dieulafoy`s lesion diagnosis has been determined eventually on histologic section. Diagnostic and therapeutic approach should be individual taking patient´s condition and capabilities of department into consideration. Surgical intervention remains golden standard when hemodynamic instability occures or when endoscopy and angiography fail.

The plausible association of MTHFR and ADORA2A polymorphisms with nodules in rheumatoid arthritis patients treated with methotrexate.

OBJECTIVE: The treatment of rheumatoid arthritis (RA) patients with methotrexate (MTX) is linked to the development or progression of rheumatoid nodules. The aim of this study was to determine whether folate and adenosine pathways-related single nucleotide polymorphisms might be predictive of increased nodule formation in RA patients treated with oral MTX. METHODS: A total of 185 Caucasian RA patients were enrolled in this cross-sectional study, all of whom fulfilled the 1987 RA criteria of the American College of Rheumatology; each patient had a history of MTX treatment. RESULTS: A higher frequency of the MTHFR 1298AA genotype was found in 17 (70.8%) of 24 patients with general nodules [odds ratio (OR)=3.08, 95% confidence interval (CI): 1.20-7.69] and in 14 (73.7%) of 19 patients who developed nodules during MTX treatment (OR=3.55, 95% CI: 1.22-10.32). In contrast, a negative association with nodules during MTX treatment (OR=0.29, 95% CI: 0.08-1.10) was found for 19 (79.2%) patients with the TT genotype (rs2298383) in the adenosine A2a receptor gene (ADORA2A). However, the significance did not remain upon correction for multiple testing. The combination of MTHFR 1298AA along with ADORA2A rs2298383 CC or CT genotypes occurring in one-third of RA patients showed a higher frequency of general nodules 15/59 (25.4%) as well as developing nodules during MTX treatment 13/59 (22.0%) in comparison with the overall studied group: 24/185 (13.0%) and 19/185 (10.3%), respectively. CONCLUSION: This exploratory study indicates for the first time a plausible association of adenosine and folate pathways single nucleotide polymorphisms in nodules' etiopathogenesis.

Small intestinal injury in NSAID users suffering from rheumatoid arthritis or osteoarthritis.

The goal of this prospective study was to assess non-steroidal anti-inflammatory drug (NSAID)-induced enteropathy in patients with rheumatoid arthritis (RA) or osteoarthritis (OA) by means of non-invasive wireless capsule enteroscopy. A total of 143 patients (74 with RA, 69 with OA) treated with NSAIDs (>1 month) and 42 healthy volunteers were included. All subjects underwent capsule endoscopy, laboratory tests and filled in questionnaires. The severity of small bowel injury was graded as: mild (red spots or sporadic erosions), moderate (10-20 erosions) or severe (>20 erosions or ulcers). Capsule endoscopy identified small bowel lesions in 44.8 % of patients (mild 36.4 %, moderate 3.5 % and severe in 4.9 %). Mild non-specific lesions were found in 11.9 % healthy volunteers. There was a significantly higher prevalence of enteropathy in RA (56.8 %) compared to OA (31.9 %, p < 0.01). A significant difference between NSAID users (RA and OA) with and without enteropathy was observed in erythrocytes (p < 0.01), the leucocyte count (p < 0.05), haemoglobin (p < 0.05), haematocrit (p < 0.05), serum albumin (p < 0.01) and erythrocyte sedimentation rate (p < 0.05). No relationship was found between enteropathy and dyspepsia, gender or age. NSAID therapy is associated with a significant risk of small bowel injury. The risk is significantly higher in RA patients suggesting a possible influence of the underlying disease. TRIAL REGISTRATION NUMBER: DRKS00004940.

Risk Factors of Acute Pancreatitis in Oral Double Balloon Enteroscopy.

Double balloon enteroscopy (DBE) was introduced 15 years ago. The complications of diagnostic DBE are rare, acute pancreatitis is most redoubtable one (incidence about 0.3%). Hyperamylasemia after DBE seems to be a rather common condition respectively. The most probable cause seems to be a mechanical straining of the pancreas. We tried to identify patients in a higher risk of acute pancreatitis after DBE. We investigated several laboratory markers before and after DBE (serum cathepsin B, lactoferrin, E-selectin, SPINK 1, procalcitonin, S100 proteins, alfa-1-antitrypsin, hs-CRP, malondialdehyde, serum and urine amylase and serum lipase). Serum amylase and lipase rose significantly with the maximum 4 hours after DBE. Serum cathepsin and procalcitonin decreased significantly 4 hours after DBE compared to healthy controls and patients values before DBE. Either serum amylase or lipase 4 hours after DBE did not correlate with any markers before DBE. There was a trend for an association between the number of push-and-pull cycles and procalcitonin and urine amylase 4 hours after DBE; between procalcitonin and alfa-1-antitrypsin, cathepsin and hs-CRP; and between E-selectin and malondialdehyde 4 hours after DBE. We found no laboratory markers determinative in advance those patients in a higher risk of acute pancreatitis after DBE.

Wireless Capsule Enteroscopy in Healthy Volunteers.

INTRODUCTION: The aim of our prospective study was to define endoscopy appearance of the small bowel in healthy volunteers. METHOD: Forty-two healthy volunteers underwent wireless capsule endoscopy, clinical investigation, laboratory tests, and completed a health-status questionnaire. All subjects were available for a 36-month clinical follow-up. RESULTS: Eleven subjects (26%) had fully normal endoscopy findings. Remaining 31 persons (74%), being asymptomatic, with normal laboratory results, had some minor findings at wireless capsule endoscopy. Most of those heterogeneous findings were detected in the small intestine (27/31; 87%), like erosions and/or multiple red spots, diminutive polyps and tiny vascular lesions. During a 36-month clinical follow-up, all these 42 healthy volunteers remained asymptomatic, with fully normal laboratory control. CONCLUSIONS: Significant part of healthy subjects had abnormal findings at wireless capsule endoscopy. These findings had no clinical relevance, as all these persons remained fully asymptomatic during a 36-month follow-up. Such an endoscopic appearance would be previously evaluated as "pathological". This is a principal report alerting that all findings of any control group of wireless capsule endoscopic studies must be evaluated with caution.

Impact of tacrine and 7-methoxytacrine on gastric myoelectrical activity assessed using electrogastrography in experimental pigs.

OBJECTIVES: Tacrine was the first acetylcholinesterase inhibitor approved for therapy of Alzheimer's disease. It has currently been withdrawn in some countries mostly due to the risk of hepatotoxicity and might be replaced by its derivate 7-methoxytacrine (7-MEOTA). The aim of this study was to assess the impact of these two compounds on gastric myoelectrical activity by means of surface cutaneous electrogastrography (EGG). METHODS: Twelve pigs (Sus scrofa f. domestica, weighing 30-35 kg) entered the study. A single dose of tacrine (200 mg i.m., n=6) or 7-MEOTA (200 mg i.m., n=6) was administrated. All EGG recordings were performed under general anaesthesia in the morning after 24 hours of fasting. Basal (30 minutes) and study recordings (150 minutes) were accomplished using an EGG stand (MMS, Enschede, the Netherlands). Results were expressed as dominant frequency of gastric slow waves, power analysis (areas of amplitudes) and power ratio assessment (ratio of the areas of amplitudes after and before study drug administration). RESULTS: Tacrine decreased EGG dominant frequency 10 minutes after its administration (from basal 3.1±0.6 to 2.8±0.6 cycles per minute; p=0.014). Tacrine induced a non-significant 60-minute increase of the power (with maximal value 493±533 µV2 at 20 minutes) and power ratio (with maximal value 2.04±3.4 at 10 minutes). Tacrine caused substantial gastric arrhythmia. 7-MEOTA did not influence dominant frequency of gastric slow waves significantly. 7-MEOTA caused a short-term late increase of the power ratio at 60 minutes (6.3±11.2; p=0.003). Blood cholinesterase activity did not correlate with any EGG parameter either after tacrine or 7-MEOTA at any time. CONCLUSIONS: Tacrine and 7-MEOTA have different impacts on EGG. Tacrine decreased dominant frequency and induced long-lasting gastric arrhythmia. 7-MEOTA caused a short-term late increase of the EGG power in experimental pigs.

Oesophageal Manometry in Experimental Pigs: Methods and Initial Experience.

The aim of this study project was to prepare our own method of porcine oesophageal manometry. Ten mature experimental pigs entered the study. Conventional water-perfused system was decided for manometry. Porcine resting and relaxed pressures of the lower oesophageal sphincter are fully comparable with healthy human subjects. Evocable swallowing is doable and oesophageal peristalsis is quantifiable. Basic manometric parameters were different in male and female animals. Oesophageal manometry in experimental pigs is feasible. Porcine oesophageal manometry will be usable for preclinical studies in future.

Cytomegalovirus disease in patients with common variable immunodeficiency: three case reports.

Common variable immunodeficiency (CVID) is the most frequent clinically relevant primary immunodeficiency and shows enormous heterogeneity in clinical presentation. Despite clinical immunodeficiency, opportunistic infections are not a typical manifestation of CVID. A retrospective study of 32 patients followed up for 335 patient-years was performed to determine the frequency of cytomegalovirus (CMV) disease. Symptomatic CMV infection was documented in 3 CVID patients. Patients No. 1 and 2 suffered from CMV pneumonia, with complications due to atypical mycobacteriosis in patient No. 1. Patient No. 3 suffered from CMV enteritis. A history of cancer and chronic hepatitis C infection (patient No. 1), immunosuppressive therapy for interstitial lung disease (patient No. 2) and serious enteropathy complicated with malnutrition (patient No. 3) may have contributed to the complications despite only mild abnormalities in T-cell subpopulations. The direct detection of CMV in bronchoalveolar lavage, stool or tissue samples was the most beneficial diagnostic laboratory method, whereas the detection of CMV DNA in blood did not produce positive results. Adequate treatment of CMV disease led to significant clinical improvement in all 3 patients. The frequency of CMV disease appears to be higher than previously described. In our experience, the probability of opportunistic infections in CVID patients increases with secondary comorbidities and their management.

HI-6 oxime (an acetylcholinesterase reactivator): blood plasma pharmacokinetics and organ distribution in experimental pigs.

OBJECTIVES: Oxime HI-6 DMS (dimethanesulfonate) is an asymmetric bis-pyridinium aldoxime and essential acetylcholinesterase (AChE) reactivator. The high effectiveness is due to its wide spectrum of therapeutic activity against different structures of nerve agents. Aim of this study was to compare plasma time profiles and tissue distribution (to delimitation of potential toxicity risks) after its intramuscular (i.m.) and intragastric (i.g.) administration to experimental pigs. METHODS: The study entered female Landrace pigs (Sus scrofa f. domestica), 4-5 months old animals, 29 ± 3.2 kg of body weight. Before the HI-6 DMS administration (i.m. injection or i.g. using a gastric tube), vena auricularis was cannulated (under general anaesthesia) for collection of blood samples. The tissue distribution study was carried out at expected t-max. Concentrations of HI-6 DMS in blood plasma and other tissue samples were detected by means of HPLC method. RESULTS: Fast absorption after i.m. administration, relatively slow absorption and no even elimination after i.g. administration were found. Tissue distribution showed low accumulation in the liver, but a higher content in the kidneys and high concentrations in the brain and gastrointestinal wall. CONCLUSIONS: Plasma time profiles after i.g. administration has a prolonged pharmacokinetics. Tissue distribution study showed potential side effects to the stomach due to a higher accumulation of HI-6 in this tissue after i.g. administration but not after a standard i.m. administration. Higher content of HI-6 in the kidneys after i.m. administration suggests the main way of the oxime elimination.

[Epidemiology of dyspepsia]. / Epidemiologie dyspepsie.

Epidemiology of uninvestigated dyspepsia was studied in the Czech Republic for the first time in 2001. The aim of our current multi-centre prospective study was to evaluate dyspepsia using the same methods in a representative sample of general unselected population from the same geographical areas 10 years later. A total of 22 centres entered the study. A total of 1,836 subjects (aged 5-98 years) were enrolled. The overall prevalence of dyspepsia was 12 %; namely 3.5 % in subjects aged 5-24 years, 18 % among 25-64-year-old persons and 15 % in subjects 65 years. Despite the substantial decrease of Helicobacter pylori infection in the Czech Republic over the past 10 years, the prevalence and basic socio-demographic determinants of uninvestigated dyspepsia did not change significantly.

The effect of general anaesthesia on gastric myoelectric activity in experimental pigs.

BACKGROUND: Surface electrogastrography (EGG) is a non-invasive method for clinical assessment of gastric myoelectrical activity. Different forms of general anaesthesia might have various effects on porcine EGG. The aim of this study was to evaluate the impact of different anaesthetic agents on EGG in experimental pigs. METHODS: Four 15-minute EGG intervals were recorded and analysed. A baseline EGG recording was started 20 minutes after intramuscular injection of ketamine and azaperone (periods A and B). Four different regimens of general anaesthesia followed immediately after the baseline EGG (5 pigs in each experimental group): thiopental, isoflurane, nitrous oxide and isoflurane plus nitrous oxide. EGG recordings followed for the next 30 minutes under general anaesthesia (periods C and D). The dominant frequencies of slow waves were compared between the baseline intervals A and B and periods C and D under general anaesthesia. RESULTS: The mean dominant frequency was within the normal range (2.3 - 3.5 cycles per minute) in all animals in all regimens. Thiopental general anaesthesia did not influence any change of the dominant frequency of slow waves. Nitrous oxide general anaesthesia increased the dominant frequency of slow waves in a statistically significant manner (baseline: 2.93 ± 0.53 and 3.01 ± 0.53; under general anaesthesia: 3.25 ± 0.34 and 3.29 ± 0.38 cycles per minute; p < 0.001, p = 0.003, p < 0.001, p < 0.001). Nitrous oxide together with isoflurane induced a statistically significant decrease of dominant frequency in the last 15-minute interval (2.66 ± 0.55 cycles per minute) compared to the baseline recording (2.81 ± 0.49; p = 0.030). CONCLUSIONS: All changes of porcine gastric myoelectric activity assessed by the dominant frequency of slow waves during EGG remained within the normal range although some of them achieved statistical significance. Thus all tested agents used for general anaesthesia can be recommended in preclinical studies with porcine models focused on gastric myoelectric activity without any risk of compromising the results. Thiopental seems to be the most suitable as it did not cause any changes at all.

Intravenous application of HI-6 salts (dichloride and dimethansulphonate) in pigs: comparison with pharmacokinetics profile after intramuscular administration.

OBJECTIVES: Oxime HI-6 is an acetylcholinesterase reactivator therapeutically efficient against nerve agents. Because of their physico-chemical properties, oximes are typically applied intramuscularly (i.m.). This route of administration has also some disadvantages, and alternative strategies ought to be examined. We evaluated the pharmacokinetic profiles of two HI-6 salts after their intravenous (i.v.) administration, and compare the results with the known pharmacokinetics after i.m. administration. METHODS: Pigs were administered with HI-6 salts (i.v), either HI-6 dichloride (10.71 mg/kg) or molar equivalent HI-6 dimethansulphonate (13.59 mg/kg). Doses of the HI-6 salts corresponded with a standard HI-6 dichloride dose in one autoinjector (500 mg) and were recalculated for one kilogram of body weight. RESULTS: The main pharmacokinetic parameters are comparable after i.v. and i.m. HI-6 administration. The compared pharmacokinetic parameters were half-life, terminal rate constant, mean residence time of the molecule in the body, clearance, and the apparent volume in the terminal phase. The bioavailability after i.m. administration was comparable with that of i.v.; these results suggest that the oxime is well released from the muscle depot. Significant differences were found in parameters Cmax and Tmax which are important in cases of emergency when rapidity and bioavailability are paramount for the success of treatment. CONCLUSIONS: I.v. administration should solve the problem of rapid clearance. Infusion or bolus administration may be considered as a logical subsequent step in oxime treatment strategy. The main advantage is in maintenance of an effective therapeutic plasma concentration, a more easily achievable effective therapeutic concentration, and fewer local adverse reactions.

Impact of paraoxon followed by acetylcholinesterase reactivator HI-6 on gastric myoelectric activity in experimental pigs.

OBJECTIVES: Organophosphorus compounds represent nerve agents, pesticides and several industrial compounds. Treatment after exposure to organophosphates involves the use of parasympatolytics, acetylcholinesterase (AChE) reactivators/modulators and anticonvulsive drugs. Wider clinical use of several AChE reactivators/modulators might be limited because of possible side effects, including gastrointestinal toxicity. In this study we evaluated the effect of paraoxon and an AChE reactivator (HI-6) on the gastric myoelectric activity in experimental pigs. METHODS: Six female experimental pigs (mean weight 33 kg) entered the study. Intramuscular paraoxon (1.5 g) was administrated after the baseline gastric electrogastrography (EGG) recording, followed by HI-6 dimethansulphonate (1.5 g i.m.) 10 min. later. A further ten 15-minute-interval EGG recordings were performed. Running spectral analysis was used for the elemental evaluation of the EGG. The results were expressed as dominant frequency of slow waves at all intervals of EGG recordings. EGG power analysis was performed in all animals. RESULTS: Paraoxon induced a non-significant decrease of dominant frequency (2.8±0.6 vs. 2.6±0.5 cycles per min.; p=0.092). Subsequent administration of HI-6 normalised dominant frequency to basal values and increased it significantly within the subsequent 30 minutes (3.0±0.4; p<0.001). Paraoxon administration did not influence the power (within a 10-minute exposure). However, the amplitudes increased significantly 90 minutes after administration of HI-6 (819±109 vs. 5054±732 µV2; p<0.001). CONCLUSIONS: AChE reactivator HI-6 blocked the gastric effect of paraoxon significantly. Subsequent myoelectric changes in the dominant frequency and power were executed by HI-6. The effect of paraoxon was non-significant.