488 An Evaluation of Pain Related Outcomes Following Nerve Sheath Catheter Insertion after Major Lower Limb Amputations

Aim

Limb amputations have many post-op complications, including pain. The evidence supporting the use of nerve sheath catheters (NSC) to manage post-op pain is mixed. Current literature suggests NSC reduces post-op opioid requirements but does not reduce pain score, phantom limb pain or chronic stump pain. This study compared post-op pain in those with and without NSC after above knee amputations (AKA) and below knee amputations (BKA).

Method

Retrospective data from April 2014 – March 2017 was reviewed. Information regarding indication, anaesthetic, morphine requirement at 72 hours, phantom limb, chronic limb pain and a pain scale (1-10) at 24, 48 and 72 hours were collected.

Results

32 patients were involved in the study. 11 had NSC for pain control. Of those patients without NSC, 43% experienced no pain. In comparison, 33% of those with NSC experienced no post-op pain. Phantom limb pain was experienced in a higher proportion of patients with NSC (18%) and in those with AKA (11%). 18% of patients with NSC experienced chronic limb pain, compared to 33% without NSC. 62% of patients with NSC required morphine at 72 hours and at higher dosages compared to those without. However, two patients used large amounts of morphine potentially giving spurious results.

Conclusions

Though limited by small patient group, patients with NSC were more likely to require morphine at 72 hours and at higher dosages but were less likely to experience chronic limb pain thus proving the role of NSC in post-op pain control.

Immigration Status as the Foundational Determinant of Health for People Without Status in Canada: A Scoping Review

Migration is increasing at unprecedented rates worldwide, but inadequate mechanisms for granting citizenship or permanent residence have rendered many immigrants without legal status. We study the health of people without immigration status in Canada, building on a 2010 review on being without status and health. We employ an expanded definition of health, guided by the WHO Social Determinants of Health (SDoH) framework. Using a scoping review methodology, we reviewed literature from 2008 to 2018 on the SDoH of people without legal immigration status in Canada, selecting 33 articles for analysis. We found that structural determinants of health, such as stigmatization and criminalization, and intermediary determinants, such as fear of deportation and healthcare avoidance, produce ill health. We show how different social positions are produced by SDoH, finding immigration status to be the foundational determinant of health for people without status in Canada. We argue that lack of immigration status as a SDoH is missing from the WHO framework.

Transforming our relationship with the social determinants of health: a scoping review of social justice interventions in Canadian Medical Schools

This article was migrated. The article was marked as recommended. Background/Purpose: Physicians are in a powerful position to improve the health status of communities through mitigating disparities rooted in social inequities. However, it is uncertain whether medical schools are preparing future physicians with the skills needed to care for diverse populations. The current scoping review aimed to describe how Canadian medical schools teach social justice, comparing pedagogical strategies. Methods: A search was performed using OVID to identify published studies of implemented and evaluated social justice-based interventions within Canadian medical school curricula. Results: Six studies were included. Common themes included increased content knowledge, greater understanding of SDoH, acknowledgement of power and privilege imbalances, identification of physicians' roles as advocates, emphasis on the importance of interdisciplinary care, and increased capacity for self-reflection and personal growth. Experiential interventions were associated with greater personal transformation, but had limited accessibility. Conclusion: Despite the widespread recognition of physicians' roles as health advocates, there is a lack of consensus about an effective strategy for teaching social justice in medical education in Canada. While additional research focusing on the relative merits of didactic versus experiential learning is needed, these preliminary results suggest that experiential learning emphasizing self-reflection and personal growth may be optimal when approaching transformative learning.

Population-based cohort study of variation in the use of emergency cholecystectomy for benign gallbladder diseases

Background

The aims of this prospective population-based cohort study were to identify the patient and hospital characteristics associated with emergency cholecystectomy, and the influences of these in determining variations between hospitals.

Methods

Data were collected for consecutive patients undergoing cholecystectomy in acute UK and Irish hospitals between 1 March and 1 May 2014. Potential explanatory variables influencing the performance of emergency cholecystectomy were analysed by means of multilevel, multivariable logistic regression modelling using a two-level hierarchical structure with patients (level 1) nested within hospitals (level 2).

Results

Data were collected on 4744 cholecystectomies from 165 hospitals. Increasing age, lower ASA fitness grade, biliary colic, the need for further imaging (magnetic retrograde cholangiopancreatography), endoscopic interventions (endoscopic retrograde cholangiopancreatography) and admission to a non-biliary centre significantly reduced the likelihood of an emergency cholecystectomy being performed. The multilevel model was used to calculate the probability of receiving an emergency cholecystectomy for a woman aged 40 years or over with an ASA grade of I or II and a BMI of at least 25·0 kg/m2, who presented with acute cholecystitis with an ultrasound scan showing a thick-walled gallbladder and a normal common bile duct. The mean predicted probability of receiving an emergency cholecystectomy was 0·52 (95 per cent c.i. 0·45 to 0·57). The predicted probabilities ranged from 0·02 to 0·95 across the 165 hospitals, demonstrating significant variation between hospitals.

Conclusion

Patients with similar characteristics presenting to different hospitals with acute gallbladder pathology do not receive comparable care.

A systematic review of type 2 diabetes mellitus and hypertension in imaging studies of cognitive aging: time to establish new norms

The rising prevalence of type 2 diabetes (T2DM) and hypertension in older adults, and the deleterious effect of these conditions on cerebrovascular and brain health, is creating a growing discrepancy between the "typical" cognitive aging trajectory and a "healthy" cognitive aging trajectory. These changing health demographics make T2DM and hypertension important topics of study in their own right, and warrant attention from the perspective of cognitive aging neuroimaging research. Specifically, interpretation of individual or group differences in blood oxygenation level dependent magnetic resonance imaging (BOLD MRI) or positron emission tomography (PET H2O(15)) signals as reflective of differences in neural activation underlying a cognitive operation of interest requires assumptions of intact vascular health amongst the study participants. Without adequate screening, inclusion of individuals with T2DM or hypertension in "healthy" samples may introduce unwanted variability and bias to brain and/or cognitive measures, and increase potential for error. We conducted a systematic review of the cognitive aging neuroimaging literature to document the extent to which researchers account for these conditions. Of the 232 studies selected for review, few explicitly excluded individuals with T2DM (9%) or hypertension (13%). A large portion had exclusion criteria that made it difficult to determine whether T2DM or hypertension were excluded (44 and 37%), and many did not mention any selection criteria related to T2DM or hypertension (34 and 22%). Of all the surveyed studies, only 29% acknowledged or addressed the potential influence of intersubject vascular variability on the measured BOLD or PET signals. To reinforce the notion that individuals with T2DM and hypertension should not be overlooked as a potential source of bias, we also provide an overview of metabolic and vascular changes associated with T2DM and hypertension, as they relate to cerebrovascular and brain health.

Vein interposition cuffs decrease the intimal hyperplastic response of polytetrafluoroethylene bypass grafts

PURPOSE

The modification of the distal anastomosis of polytetrafluoroethylene (PTFE) bypass grafts with vein interposition cuffs (VCs) has been reported to increase graft patency. However, the mechanisms that are responsible for this improved patency are unclear. Because intimal hyperplasia (IH) is a primary cause of prosthetic graft failure, we hypothesized that VCs affect the distal anastomosis by decreasing the IH response of the outflow artery.

METHODS

Twenty-three female domestic Yorkshire pigs (mean weight, 35 kg) underwent 42 femoral PTFE bypass grafting procedures. The PTFE bypass grafts were separated into the following three groups according to distal anastomotic configuration: end-to-side anastomoses (ES), VCs, and cuffs constructed with PTFE (PCs). Four femoral arteries from two pigs served as healthy controls. At sacrifice, the grafts were perfusion fixed, and the distal anastomoses harvested at 1 and 4 weeks. The specimens were hemisected and serially sectioned to identify the heel, toe, and mid-anastomotic regions. The sections were cut into 5-microm segments and analyzed for intima and media thickness and area, intima/media area ratio, and the distribution of IH in the vein cuff. The roles of transforming growth factor-beta1 and platelet-derived growth factor-BB in IH development were assessed with immunohistochemistry.

RESULTS

IH development was significantly lower at all areas of the anastomosis, with VCs compared with ES and PCs at 4 weeks (P </=.001). IH decreased in VCs from 1 to 4 weeks in all areas of the anastomosis (P </=.001). PCs showed pronounced IH at the mid-anastomosis as compared with VCs and ES (P </=.001). IH was most pronounced at the toe with ES and PCs (P </=.001). Qualitatively, VCs altered the site of IH development, sparing the recipient artery with preferential thickening of the vein cuff and formation of a pseudointima at the vein-PTFE interface. Immunohistochemistry results showed positive staining for transforming growth factor-beta1, platelet-derived growth factor-BB, and smooth muscle alpha-actin in the hyperplastic intima.

CONCLUSION

PTFE bypass grafts with VCs had less IH develop than did grafts with ES and PC anastomoses. IH regression in VCs at 4 weeks suggests compensatory vessel wall remodeling mediated by the presence of the VC. Furthermore, VCs caused a redistribution of hyperplasia to the vein-PTFE interface, delaying IH-induced outflow obstruction in the recipient artery. The marked increase in IH with PCs, despite a similar geometric configuration to VCs, suggests that the biologic properties of autogenous tissue dissipate IH development. Similarly, the flow patterns in PCs and VCs should be identical, which suggests a less important role of hemodynamic forces in VC-mediated protection.

Patency and limb salvage for polytetrafluoroethylene bypasses with vein interposition cuffs

Polytetrafluoroethelene (PTFE) is often utilized in patients with limb-threatening ischemia requiring infrainguinal revascularization in the absence of autologous saphenous vein. To increase long-term patency of PTFE grafts, vein interposition cuffs have been recommended as adjunctive procedures. The purpose of this study was to assess the efficacy of vein interposition cuffs on the long-term patency and limb salvage of patients requiring prosthetic bypass grafts for limb-threatening ischemia. Prosthetic bypass grafts with vein interposition cuffs (PTFE/VC) were performed on 56 limbs in 55 patients (32 men, 23 women; mean age of 67 years) from October 1993 to January 1998. Grafts were prospectively evaluated every 3 months for the first 12 months and biannually thereafter with duplex ultrasonography. PTFE/VC and PTFE bypasses at the popliteal level appear to have comparable patencies. However, PTFE/VC appear to offer an improved patency and limb salvage for infrapopliteal bypasses in patients with critical limb ischemia. When infrapopliteal revascularization is required in the absence of autologous saphenous vein, we recommend the use of PTFE with vein interposition cuffs.