Attenuation Of Portosystemic Shunts Research Articles

Use of intraoperative transsplenic injection of agitated saline to confirm temporary full attenuation of congenital extrahepatic portosystemic shunts in dogs.

To describe the use of intraoperative transsplenic injection of agitated saline (TIAS) and confirm temporarily full attenuation of extrahepatic portosystemic shunt (EHPSS) in dogs. Retrospective case series. A total of 40 dogs. Medical records of dogs that underwent surgical attenuation of EHPSS between January 2014 and May 2021 were reviewed. A ventral midline celiotomy was performed, the EHPSS identified and dissected, and temporal occlusion performed using Rummel tourniquets or silicone vascular loops. A wide range microconvex transducer was used to visualize the right atrium via a subxiphoid acoustic window. Agitated saline was injected into the splenic parenchyma while the right atrium was ultrasonographically monitored before and after temporary occlusion of the EHPSS. Case details, intra- and postoperative findings, and long-term outcome were recorded. The agitated saline was immediately identified within the right atrium after injection into the splenic parenchyma before temporary occlusion of the EHPSS in all cases. After temporary occlusion, the agitated saline was not observed within the right heart, except in two dogs in which a second vessel bypassing the liver circulation was identified. No intra- or postoperative complications were recorded. Long-term clinical outcome was considered good to excellent in all cases. Intraoperative TIAS confirmed temporary full attenuation of EHPSS. Intraoperative TIAS is an easy, safe and reproducible technique to assess intraoperative full occlusion of EHPSS.

Repeated specific canine pancreatic lipase measurements do not identify multiple acquired portosystemic shunts in dogs after extrahepatic portosystemic shunt attenuation.

In dogs with portal hypertension (PH), spec cPL is suggested to be increased despite normal pancreatic histology. After attenuation of congenital extrahepatic portosystemic shunts (cEHPSS), multiple acquired portosystemic shunt (MAPSS) can develop as consequence of sustained PH. Presence of MAPSS affects future therapeutic options and prognosis. Evaluate if spec cPL concentrations increase postoperatively in dogs that develop MAPSS and can thus serve as an indicator of PH. Twenty-four dogs with cEHPSS. Dogs classified according to surgical outcome after cEHPSS attenuation (8 with MAPSS [group M], 9 with closed cEHPSS [group C] and 7 with patent blood flow through the original cEHPSS, without evidence of MAPSS [group P]). Spec cPL was measured in preoperative samples (T0), 4 days (T1) and 1 (T2) and 3- to 6-months (T3) after surgery. Spec cPL was within reference interval (<200 μg/L) at all timepoints except at T1. At T1, 2 dogs in group M (321 and >2000 μg/L) and also 1 in group C (688 μg/L) and 1 in group P (839 μg/L) had increased spec cPL concentrations. No differences in spec cPL concentrations between groups or changes over time were identified. Spec cPL is not consistently increased in dogs that develop MAPSS after cEHPSS attenuation and has no potential as a biomarker for the identification of MAPSS after cEHPSS attenuation.

Prospective Study Comparing Outcome following Complete Polypropylene Suture Ligation versus Partial Thin Film Band Attenuation of Congenital Portosystemic Shunts in Dogs.

The main objective was to conduct a prospective study reporting the outcome for dogs with an extrahepatic congenital portosystemic shunt (CPSS) treated with a 'complete ligation where possible' philosophy. The second aim was to compare the outcomes following complete (C) polypropylene suture ligation versus partial thin film band (TFB) attenuation of a CPSS in dogs. Dogs that could not tolerate acute complete shunt ligation at surgery received partial shunt attenuation with TFB. Peri-operative complications, mortality, follow-up imaging findings, pre- and post-operative bile acid stimulation test results and details of any revision surgery performed were recorded. A follow-up health-related quality of life questionnaire enabled the calculation of a postoperative clinical shunt score, a quality of life score, and determined if any dogs were still on a hepatic diet and/or other medical management at a minimum of 6 months after surgery. Of the 110 dogs enrolled, 57 received complete ligation and 53 received partial TFB attenuation. Peri-operative mortality, the occurrence of post-attenuation neurological complications, the occurrence of multiple acquired shunts, the postoperative clinical shunt score and quality of life score were not significantly different between the two groups. Dogs in the C group were older, heavier and demonstrated a greater number of shunt classifications where the entry into the systemic circulation was the phrenic vein or azygous vein. Dogs in the TFB group had a greater number of unchanged bile acid concentrations after surgery, were more likely to remain on the hepatic diet and/or medical management after surgery and underwent a greater number of revision surgeries. There was variability in the precision of both ultrasound and computed tomographic angiography follow-up imaging compared to intra-operative mesenteric portovenography findings at revision surgery. Overall, dogs with an extrahepatic portosystemic shunt receiving either complete acute shunt ligation or partial TFB shunt attenuation are expected to have an excellent long-term clinical outcome and there is no reason to suggest that a dog able to tolerate complete acute shunt closure should be denied the benefit of this.

Portovenography Findings Following Partial Polypropylene Versus Thin Film Band Attenuation of a Single Congenital Extrahepatic Portosystemic Shunt: A Prospective Randomized Study in Dogs.

The objective was to conduct a prospective, randomized study to compare mesenteric portovenogram findings following partial polypropylene suture versus thin film band extrahepatic portosystemic shunt attenuation in dogs. Dogs with extrahepatic portosystemic shunts that could not tolerate complete acute shunt closure received a partial attenuation with either a polypropylene suture or synthetic polymer thin film band. At a routine second surgery three months after shunt patency, missed shunt branches and/or development of multiple acquired shunts were assessed using intra-operative mesenteric portovenography. Twenty-four dogs were enrolled, 12 received partial polypropylene suture ligation, and 12 received partial thin film band shunt attenuation. Intra-operative mesenteric portovenography three months later demonstrated that nine dogs (75%) in the thin film band group had achieved complete shunt closure versus two dogs (16.7%) in the polypropylene suture group, which was significantly different (p = 0.004). No dogs in the polypropylene suture group and two dogs (16.7%) in the thin film band group developed multiple acquired shunts. This is the first study directly comparing follow-up intra-operative mesenteric portovenography imaging findings between two methods of partial portosystemic shunt attenuation in dogs. The study provides accurate information on the rates of complete anatomical shunt closure and development of multiple acquired shunts following partial shunt attenuation with either synthetic polymer thin film band or polypropylene suture.

Opioid‐free anaesthesia for surgical attenuation of a congenital extrahepatic portosystemic shunt in a dog

AbstractAnimals with impaired hepatic metabolism may experience reduced effect from some anaesthetic drugs and are more prone to developing unwanted side effects. Due to reduced blood flow to the liver, it is important to carefully select anaesthetic drugs in patients with extrahepatic shunt. We present the case in which a dog was submitted for surgical attenuation of congenital extrahepatic portosystemic shunt through placement of an ameroid constrictor. A multimodal regimen was designed in order to provide an opioid‐free anaesthesia, relying on analgesia through a locoregional quadratus lumborum block with bupivacaine. Dexmedetomidine was administered intramuscularly as pre‐anaesthetic medication, propofol was used for the induction and anaesthesia was maintained with isoflurane. The present case describes the first case in which an extrahepatic portosystemic shunt was surgically treated using an opioid‐free anaesthesia in a dog.

Postattenuation neurologic signs after surgical correction of congenital portosystemic shunts in cats: A narrative review.

Development of postattenuation neurological signs (PANS) is a potentially severe complication after surgical attenuation of congenital portosystemic shunts in cats. This review summarizes findings of 15 publications that report occurrence of PANS in cats. PANS includes seizures but also milder neurologic signs such as blindness, ataxia, abnormal behavior, tremors, and twitching. Incidence of PANS and specifically postattenuation seizures in studies including a minimum of five cats ranges from 14.3% to 62.0% and 0% to 32.0%, respectively. Etiology of PANS in cats is unknown, however, several hypotheses have been proposed including central nervous system disease/derangement, perioperative hypoglycemia and electrolyte disturbances, and postoperative portal hypertension. A number of possible risk factors have been identified including lower grades of intraoperative postocclusion mesenteric portovenography and osmolality at 24 h postoperatively. Evidence for use of prophylactic antiepileptics such as levetiracetam to prevent or reduce incidence of PANS in cats is limited and does not support their use. Because the cause is unknown, treatment is aimed at controlling neurologic signs, preventing progression to more severe signs, and providing general supportive care. Prospective studies comparing the efficacy of different antiepileptics for treatment of PANS in cats are required. Prognosis for recovery is variable and dependent on severity of neurologic signs. For cats surviving to discharge, long-term survival is possible but persistence or recurrence of neurologic signs in the long-term is not uncommon.

Shear wave elastography measurements in dogs treated surgically for congenital extrahepatic portosystemic shunts.

Assessing the postoperative surgical success of congenital extrahepatic portosystemic shunt (EHPSS) attenuation can be challenging and involve invasive imaging methods. Elastography is an ultrasound technique that allows qualitative and quantitative estimation of tissue stiffness and has extensively been used in people with liver disease. In recent years, increased interest in this technique has developed in veterinary medicine due to its non-invasive nature, availability, and low cost. The objective of this study was to compare liver stiffness values between dogs with closed EHPSS and those with multiple acquired portosystemic shunts (MAPSS) after gradual surgical attenuation and to assess whether shear wave elastography could be used to determine EHPSS closure. As a secondary objective, measurements obtained from both intercostal and subxiphoidal views were compared. Mean values for the average, median, and maximum two-dimensional shear wave velocities (2D SWV) for the closed EHPSS were 2.88 +/−0.11 m/s; 2.83 +/−0.11 m/s; and 3.75 +/−0.16 m/s, respectively. In the MAPSS dogs, mean values for the average, median, and maximum 2D SWV were 2.77 +/– 0.17 m/s; 2.71 +/– 0.17 m/s; and 3.66 +/−0.24 m/s, respectively. No significant differences in 2D SWV were present between dogs with closed EHPSS and those with MAPSS (P = 0.33; P = 0.33; P = 0.42, respectively). When assessing potential differences between intercostal and subxiphoidal 2D SWV measurements, no effect was observed for the average and median 2D SWV (P = 0.06; P = 0.07, respectively). Yet, a significant difference was identified for the maximum 2D SWV between intercostal 4.00 +/−0.20 m/s and subxiphoidal 3.41 +/−0.17 m/s measurements (P = 0.02). The relevance of this finding is uncertain as many other studies about liver elastography only report mean and not maximum values.

Short- and long-term outcomes of polyethylene band attenuation of congenital extrahepatic portosystemic shunts in dogs: 60 cases (2010-2020).

To report the short- and long-term outcomes following attenuation of congenital extrahepatic portosystemic shunts in dogs using a novel polyethylene band. Records were retrospectively reviewed for dogs that underwent congenital extrahepatic portosystemic shunt attenuation by a polyethylene banding technique, at a single institution between 2010 and 2020. Short-term outcome data were collected from peri-operative clinical records with follow-up examinations, scheduled at 6 and 18 weeks post-operatively, and post-operative imaging when performed. Long-term follow-up was collected by validated owner questionnaire, telephone interview or medical records. Long-term outcomes were categorised by "excellent", "good" or "poor". Sixty dogs were included. Post-operative complications occurred in 10 of 60 dogs (16.7%), four major and six minor, with a peri-operative mortality of 6.7%. Persistent shunting was identified in nine of 53 dogs (17%) available for follow-up examination and four dogs underwent a revision surgery. Long-term follow-up was available for 44 dogs at a median of 75 months post-operatively (range 7 to 128). Long-term outcomes were "excellent" (26) or "good" (8) in 81.8% of dogs and "poor" (8) in 18.2%. At the time of follow-up, 30 of 44 (68.2%) dogs were not receiving any medical treatment and 27 of 28 (96.4%) questionnaire respondents were satisfied with the response to surgery. Polyethylene band attenuation of congenital extrahepatic portosystemic shunts provides comparable outcomes to cellophane. The material used in this study is widely available and consistent while being pre-sterilised and pre-folded makes it easy to use.

In dogs undergoing extrahepatic portosystemic shunt attenuation, does pretreatment with levetiracetam reduce postoperative seizure incidence?

PICO question&#x0D; PICO&#x0D; &#x0D; Clinical bottom line&#x0D; Category of research question&#x0D; Treatment&#x0D; The number and type of study designs reviewed&#x0D; Four papers were critically reviewed. All were retrospective cohort studies&#x0D; Strength of evidence&#x0D; Moderate&#x0D; Outcomes reported&#x0D; In one paper levetiracetam was found to reduce the risk of post-attenuation seizures. In the remaining three papers no difference was found between the frequency of post-attenuation seizures and the use of levetiracetam&#x0D; Conclusion&#x0D; That prophylactic levetiracetam is not indicated for the use of preventing post-attenuation seizures in dogs surgically treated for extrahepatic portosystemic shunts&#x0D; &#x0D; How to apply this evidence in practice&#x0D; The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.&#x0D; Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.&#x0D; &#x0D;

Laparoscopic portosystemic shunt attenuation in 20 dogs (2018-2021).

To describe the technique, complications, and outcome of laparoscopic portosystemic shunt attenuation (LPSSA) in dogs. Retrospective study. Twenty client-owned dogs. Medical records were searched for dogs with a single congenital extrahepatic portosystemic shunt (CEPSS) that was treated with LPSSA. Signalment, clinical signs, CEPSS location, diagnostic imaging, laparoscopic approach, operative technique, complications, and clinical outcome were reviewed. Fourteen dogs with CEPSS located in the epiploic foramen had a right (13/14) or left (1/14) paramedian approach. In 6 dogs a CEPSS was not located in the epiploic foramen, and a left paramedian approach was used. A 3 or 4-port technique was used in 7 and 13 dogs, respectively. A thin film band was used for CEPSS attenuation in all dogs. The median operating time for LPSSA was 62 min (range 27-98 min). Intraoperative complications requiring conversion to an open technique occurred in 5 dogs. Mild perioperative self-limiting portal hypertension occurred in 3 dogs, while severe portal hypertension with surgical revision occurred in 1 case. The complications were resolved, and all dogs had a good outcome. Laparoscopic portosystemic shunt attenuation can be performed in dogs, in particular for a CEPSS located in the epiploic foramen using a right paramedian approach. For CEPSS not located in the epiploic foramen, a left paramedian approach is recommended. Conversion to open celiotomy was required in around a third of cases. Laparoscopic attenuation of CEPSSs can be performed in dogs and has a good clinical outcome, particularly for CEPSS located in the epiploic foramen.

Clinical characteristics of, prognostic factors for, and long-term outcome of dogs with multiple acquired portosystemic shunts: 72 cases (2000-2018).

To identify clinical characteristics of, prognostic factors for, and long-term outcome of dogs with multiple acquired portosystemic shunts (MAPSSs) and determine whether survival time was associated with previous portosystemic shunt attenuation. 72 client-owned dogs with MAPSSs. Medical records of dogs in which MAPSSs had been diagnosed between January 2000 and August 2018 were reviewed for signalment, historic and diagnostic findings, management methods, and outcome. Median survival time of dogs (n = 23) that died of causes related to MAPSSs was 580 days (range, 156 to 1,363 days). Factors significantly associated with dying of MAPSS-related versus unrelated causes included body weight, albumin concentration at the first and last recheck examinations, and cholesterol, total solids, and glucose concentrations at the last recheck examination. Dogs not receiving medical management or without signs of depressed mentation at the time of initial presentation were less likely to die of causes related to MAPSSs. Patient status (alive vs dead of causes related to MAPSSs vs dead of causes unrelated to MAPSSs vs dead of unknown causes) was not significantly associated with survival time. Survival time for dogs with MAPSSs was not shortened by previous portosystemic shunt attenuation surgery and was not different when death was versus was not related to MAPSSs. Dogs with MAPSSs that had progression of biochemical changes consistent with liver dysfunction were more likely to die of causes related to MAPSSs and were unlikely to live a normal lifespan.

Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review

The development of postattenuation neurologic signs (PANS) is a poorly understood and potentially devastating complication after surgical attenuation of congenital portosystemic shunts in dogs. Postattenuation neurologic signs include seizures but also more subtle neurologic signs such as depression, behavioral changes, tremors, and twitching. They most commonly occur within 7 days postoperatively and are typically unrelated to hyperammonemia, hypoglycemia, or electrolyte disturbances. This narrative review summarizes the findings of 50 publications from 1988-2020 that report occurrence of PANS. While most published reports included only dogs affected by postattenuation seizures (PAS), others included dogs with any form of PANS. Overall, PANS (including PAS) affected 1.6%-27.3% of dogs, whereas incidence of PAS ranged from 0%-18.2%. The etiology of PANS remains unknown; however, several theories have been proposed. Risk factors include preoperative hepatic encephalopathy, increasing age, and possibly certain breeds and extrahepatic shunt morphology. There is increasing evidence that prophylactic antiepileptic drugs do not prevent PANS. Treatment is centered around controlling neurologic signs with antiepileptic drugs and providing supportive intensive care. The 30-day survival rate in studies that included a minimum of four dogs affected by PANS was 0%-100% (median, 50.0%) and 0%-75.0% (median, 37.5%) for those with PAS. Mortality associated with PANS was typically related to occurrence of generalized seizure activity. Prognostic factors positively associated with short-term survival included having a history of preoperative seizures and development of focal seizures only. If affected dogs survived to discharge, survival for several years was possible, and the majority of neurologic signs manifested as part of the phenomenon of PANS appeared to resolve.

Is there a rationale to supplement hepatotropic factors to dogs with multiple acquired portosystemic shunts secondary to congenital portosystemic shunt attenuation?

Experimental rat models and clinical trials in human patients with liver cirrhosis show evidence that supplementation with hepatotropic factors provides therapeutic benefits. This form of support has not yet been described in dogs with multiple acquired portosystemic shunts (MAPSS) despite similarities between both pathological conditions. Especially hepatocyte growth factor (HGF) and branched chain amino acids (BCAA) deserve closer attention. High-quality vegetable rather than animal proteins have been suggested to form an excellent dietary source of BCAA, and leucine seems the best candidate for supplementation given its stimulating effects on liver function in general and on HGF secretion specifically. Research on optimal ways of administration of HGF in dogs with MAPSS secondary to congenital portosystemic shunt attenuation is necessary before clinical trials can be initiated.

Serum insulin-like growth factor-1 as a marker of improved liver function and surgical outcome in dogs with congenital extrahepatic portosystemic shunts

Serum insulin-like growth factor-1 concentration (sIGF-1c) is reduced in various hepatopathies in humans and dogs. This work aimed to evaluate sIGF-1c in dogs before and after congenital extrahepatic portosystemic shunt (cEHPSS) attenuation, in relation to surgical outcome (closed vs. persistent shunting). Secondarily, it aimed to assess if sIGF-1c can discriminate between cEHPSS and portal vein hypoplasia (PVH) and finally compare sIGF-1c ratio (postoperative/preoperative sIGF-1c) to pre-prandial serum bile acids (preBA), post-prandial bile acids (postBA), bile acid stimulation test (BAST) and fasting ammonia (FA), regarding surgical outcome. Thirty-nine dogs were included: 15 with closed cEHPSS, 15 with persistent shunting and nine with PVH. Transplenic portal scintigraphy was used to classifiy surgical outcome.There was no significant difference in sIGF-1c between dogs with cEHPSS and those with PVH (P > 0.05). Postoperative sIGF-1c increased in all dogs (P < 0.001 and P = 0.023 for closed and persistent shunting, respectively) and the increase was more pronounced in closed cEHPSS than in persistent shunting (P = 0.006). Using an optimal sIGF-1c ratio cut-off of 2.23, the sensitivity was 93.3% and the specificity was 66.7% for differentiation between surgical outcomes. Serum pre-prandial bile acids, postBA BAST and FA had sensitivities of 80%, 86.7%, 86.7%, 60%; and specificities of 100%, 93.3%, 93.3%, 100%, respectively. There was a greater increase in sIGF-1c after shunt closure than during persistent shunting; nevertheless sIGF-1c ratio was inferior to advanced imaging to assess surgical outcome.

Serum hyaluronic acid, a marker for improved liver perfusion after gradual surgical attenuation of extrahepatic portosystemic shunt closure in dogs

Current liver function tests used in dogs do not consistently normalise after successful surgical attenuation of portosystemic shunts (PSS). Serum hyaluronic acid (sHA) concentrations in dogs with PSS are reported to be higher at diagnosis than in healthy dogs. The objective of this study was to assess sHA as a marker of liver perfusion by measuring sHA concentrations in dogs before and after gradual surgical attenuation of extrahepatic (EH)PSS and by determining whether sHA concentrations could differentiate closed EHPSS from persistent shunting. Specificity of sHA was assessed by comparing sHA concentrations in dogs with EHPSS to those in dogs with other liver diseases.Twenty dogs with EHPSS had sHA concentrations measured at diagnosis, 1, 3, and 6 months postoperatively. In addition, sHA concentrations were determined in 10 dogs with other liver diseases. At EHPSS diagnosis, median sHA concentration was 335.6 ng/mL (43.0−790.7 ng/mL). All dogs had a significant decrease in sHA concentrations from 1 month postoperatively onwards (P < 0.05), regardless of surgical outcome. At all postoperative follow-up visits, there was a significant difference between the median sHA concentration in dogs with closed EHPSS vs. those with persistent shunting (P < 0.05). Median sHA concentration in dogs with other liver diseases was 89.8 ng/mL (22.9−160.0 ng/mL), which was significantly lower than dogs with EHPSS at diagnosis (P < 0.001). In conclusion, sHA is a promising non-invasive biomarker that can help to determine liver perfusion after surgical attenuation of EHPSS. In addition, sHA could potentially be used to differentiate dogs with EHPSS from dogs with other liver diseases.

Incidence and risk factors for neurological signs after attenuation of a single congenital portosystemic shunt in 50 cats.

To determine the incidence, outcome, and risk factors for postattenuation neurological signs (PANS) in cats treated for single congenital portosystemic shunts (CPSS). Retrospective cohort study. Cats (n = 50) with a single CPSS. Medical records of cats treated by surgical attenuation of a single CPSS between 2003 and 2017 were reviewed for signalment, surgical technique, preoperative management and postoperative clinical outcomes. Binary logistic regression was performed to investigate risk factors for occurrence of PANS and seizures. Congenital portosystemic shunts in 50 cats included 40 extrahepatic and 10 intrahepatic shunts. Postattenuation neurological signs were recorded in 31 (62%) cats and graded as 1 in 10 cats, 2 in nine cats, and 3 in 12 cats. Postattenuation neurological signs included seizures in 11 cats. Five of 31 cats with PANS did not survive to discharge. No association was detected between PANS or seizures and the type of CPSS (intrahepatic or extrahepatic), degree of attenuation, age, or the use of perioperative levetiracetam or hepatic encephalopathy immediately preoperatively. Osmolality at a median 24 hours postoperatively was lower in cats with PANS (P < .049, Wald 3.867, odds ratio [Exp(B)] 0.855, CI 0.732-0.999). Postattenuation neurological signs are common complications in cats treated for CPSS. Preoperative levetiracetam did not prevent the occurrence of PANS or seizures. The only risk factor for PANS detected was lower postoperative Osmolality in cats with PANS at 24 hours. Postattenuation neurological signs including seizures occur frequently in cats undergoing surgical attenuation of a CPSS. Preoperative levetiracetam did not protect against the development of PANS.

Brain MRI findings in a dog with late onset epileptic seizure after portosystemic shunt attenuation

A female Tibetan terrier aged five years and six months presented 23 months after portosystemic shunt attenuation due to generalised tonic–clonic epileptic seizure activity. Repeat MRI of the brain showed...

Diagnostic value of blood variables following attenuation of congenital extrahepatic portosystemic shunt in dogs

BackgroundThe aims of this study were to determine if extrahepatic portosystemic shunt (EHPSS) postoperative closure could be predicted based on preoperative blood analyses and to determine the accuracy of blood...

The effect of neuraxial morphine on postoperative pain in dogs after extrahepatic portosystemic shunt attenuation

ObjectiveTo investigate the analgesic effect of epidural morphine after surgical extrahepatic portosystemic shunt (EHPSS) attenuation. Study designRandomized clinical trial. AnimalsA total of 20 dogs with a congenital EHPSS. MethodsDogs were randomly allocated to be given either a single epidural dose of 0.2 mg kg–1 preservative-free morphine (group M) or not (group C) before surgery. All dogs were administered 0.3 mg kg–1 methadone intravenously (IV) as preanaesthetic medication. Pain scores were determined every 2 hours for the first 24 hours postoperatively using the short-form Glasgow Composite Measure Pain Scale (GCMPS-SF). Dogs with a GCMPS-SF pain score >4/20 or >5/24 received 0.1 mg kg–1 methadone IV as rescue analgesia and were reassessed 30 minutes later. If more than three doses of methadone were administered in a 2 hour period, alternative pain relief was provided and a treatment failure recorded. The GCMPS-SF pain scores and number of rescue analgesia injections were analysed over 24 hours. The last observation carried forward method was applied in case of treatment failure. Food consumption and time to first urination were recorded. Data were analysed using a Mann–Whitney U test and presented as median (minimum–maximum range), with significance set at p < 0.05. ResultsGroup M showed lower GCMPS-SF pain scores [15 (11–41) versus 31 (11–86); p = 0.023] and lower postoperative methadone requirements [0 (0–0.2) versus 0.25 (0–0.5) mg kg–1; p = 0.029] than group C. There were three treatment failures in group C only. Food consumption and time to first urination did not differ between groups. Conclusions and clinical relevanceEpidural morphine reduced the requirement for postoperative analgesia in this study population.

The chemical and ultra-structural analysis of thin plastic films used for surgical attenuation of portosystemic shunts in dogs and cats

The objective of the study was to (1) characterize and compare the chemical composition at the surface, subsurface and in the bulk of thin plastic films used for portosystemic shunt attenuation in their native state and after plasma exposure. (2) Assess the presence, concentration and location of irritant compounds (e.g dicetyl phosphate) within the films.Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), X-ray Photoelectron Spectroscopy (XPS) and dynamic Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) were used to analyze thirteen thin plastic films. Sample thickness was visualized and measured using Scanning Electron Microscopy (SEM). Sample thicknesses were compared using a one-way ANOVA.XPS reported low phosphorous concentrations (surrogate marker of dicetyl phosphate) between 0.01 and 0.19% wt at the sample surfaces (top 10 nm). There were significant differences between film thicknesses (P < .001) observed by SEM. The ATR-IR and ToF-SIMS identified four distinct surface and bulk chemical profiles: 1) Cellophane, 2) Polypropylene, 3) Modified Cellophane, and 4) Unique. Following plasma immersion for 6 weeks, samples showed little change in film thickness or chemical composition.This study confirmed that films used to attenuate portosystemic shunts were commonly not pure cellophane, with significant variations in surface and bulk chemistry. Suspected irritant compounds were not readily identifiable in significant proportions. Pronounced variability existed in both the thickness and chemical composition of these films (surface vs. bulk). The present findings lead to a legitimate question about the reproducibility of shunt occlusion when using thin plastic films from different origins.