A human model of bilateral pulmonary vein sampling to assess the effects of one-lung ventilation on neutrophil function.

BACKGROUND: Neutrophil activation drives lung complications after cardiopulmonary bypass (CPB). Evidence suggests the healthy, ventilated lung may beneficially re-condition pro-inflammatory neutrophils. However, evidence in humans is lacking, due to a paucity of good models. CPB with simultaneous central venous and bilateral pulmonary vein sampling provides an opportunity to model effects of one-lung ventilation. The study's primary objectives were to establish a model of intra-operative, bilateral pulmonary vein sampling and to determine whether neutrophil function differed after passing through inflated or deflated lungs. METHODS: Seventeen patients having "on pump" coronary artery bypass grafting (CABG) with one-lung ventilation (in two cohorts with tidal volume 2ml kg-1 and FiO2 0.21, or tidal volume 4 ml kg-1 and FiO2 0.5 respectively) were recruited. Cohort 1 consisted of 9 patients (7 male, median age 62.0 years) and Cohort 2 consisted of 8 male patients (median age 65.5 years). Recruitment was via prospective screening of scheduled elective and non-elective CABG procedures with cardiopulmonary bypass. Each patient had five blood samples taken-central venous blood pre-operatively; central venous blood pre-CPB; central venous blood post-CPB; pulmonary venous blood draining the ventilated lung post-CPB; and pulmonary venous blood draining the deflated lung post-CPB. Neutrophil phagocytosis and priming status were quantified. Plasma cytokines were measured. RESULTS: Phagocytosis and priming were not significantly different in neutrophils returning from the ventilated lung as compared to the non-ventilated lung. Plasma IL-6, IL-8 and IL-10 were significantly elevated by CPB. CONCLUSIONS: The intra-operative, bilateral pulmonary vein sampling model provides unique opportunities to assess biological effects of interventions to one lung, with the other lung acting as an internal control. Single-lung ventilation during CPB had no significant effects on neutrophil function.

The PReliMinAry (Pain Relief in Major Amputation) Survey.

OBJECTIVES: Major Lower Limb Amputation (MLLA) is associated with significant peri- and post-operative pain and has been identified as a research priority by patient and healthcare groups. The PReliMinAry survey was designed to evaluate existing MLLA analgesia strategies; identifying areas of equipoise and informing future research. METHODS: A targeted multi-national, multi-disciplinary survey was conducted via SurveyMonkey® (October 5, 2020-November 3, 2020) and advertised via social media and society email lists. The 10-questions explored 'pain-team' services, pre-operative neuroleptic medication, pre-incision peripheral nerve blocks and catheters, surgically placed nerve catheters, post-operative adjunctive regimens, future research engagement and equipoise. RESULTS: Seventy-six responses were received from 60 hospitals worldwide. Twelve hospitals(20%) had a dedicated MLLA pain team, 7(12%) had none. Most pain teams (n = 52; 87%) assessed pain with a 0-10 numerical rating scale. Over half of respondents "never" preloaded patients with oral neuroleptic agents(n= 42/76; 55%). Forty-seven hospitals(78%) utilized patient controlled opioid analgesia. Most hospitals are able to provide pre-incision loco-regional peripheral nerve blocks, nerve catheters and surgical nerve catheters (95%, 77%, and 90% respectively), but use was variable. Ultrasound(US) guided peripheral nerve catheters were "infrequently" or "never" used in 57% of hospitals, whilst 23% "infrequently" or "never" utilize surgically placed nerve catheters. CONCLUSIONS: The survey revealed a preference towards 'single-shot' nerve blocks and surgical catheters. A difference between the use of US guided nerve catheters and those surgically placed likely reflects the difference of literature evaluating these techniques. Most respondents felt there was equipoise surrounding future trials evaluating nerve blocks/catheters, but less so for surgical catheters.

Anaemia: A risk factor for death and adverse outcomes following surgery for acute lower limb ischaemia.

INTRODUCTION: Acute limb ischaemia (ALI) forms a significant part of the vascular surgery workload and carries with it high rates of morbidity and mortality. Anaemia is also common amongst vascular surgical patients and has been linked with poor outcomes in some subgroups. We aimed to assess the frequency of anaemia in patients with ALI and its impact on survival and complications following revascularisation to help direct future efforts to optimise outcomes in this patient group. METHODS: A retrospective analysis of prospectively collected departmental data on patients undergoing surgical intervention for ALI between 2014 and 2018 was performed. Anaemia was defined as a pre-operative haemoglobin (Hb) of <120 g/L for women and <130 g/L for men. The primary outcome was overall survival, assessed with the Kaplan-Meier estimator, with application of Cox proportional hazard modelling to adjust for confounding covariates. RESULTS: There were 158 patients who underwent treatment for ALI: 89 (56.3%) of these were non-anaemic with a mean Hb of 146 (SD = 18.4), and 69 (43.7%) were anaemic with a mean Hb of 106 (SD = 13.4). Anaemic patients had a significantly higher risk of death than their non-anaemic counterparts on univariate analysis (HR = 2.11, 95% CIs, 1.28-3.5, p = 0.0036). There was ongoing divergence in survival up to around 6 months between anaemic and non-anaemic groups. Under the Cox model, anaemia was similarly significant as a predictor of death (HR = 2.15, 95% CIs, 1.17-3.95, p = 0.013), accounting for recorded comorbidities, medication use and blood transfusion. CONCLUSIONS: Anaemia is a significant and independent risk factor for death following revascularisation for ALI and can be potentially be modified. Vascular surgical centres should ensure they have robust pathways in place to identify and consider treating anaemia. There is scope for further work to assess how to best optimise a patient's levels of circulating haemoglobin.

Femoral venous aneurysms are rare, yet confer significant mortality risk due to venous thromboembolism; consider in venous thromboembolism of unknown aetiology.

Femoral venous aneurysms are a rare disease entity, yet they carry the risk of significant mortality due to venous thromboembolism, as demonstrated by a case report of an otherwise fit and well 74-year-old gentleman.

Acute Limb Ischaemia and a Disguised Pseudoaneurysm: A Rare Presentation of a Femoral Osteochondroma.

INTRODUCTION: Vascular complications occurring secondary to osteochondroma are a rare phenomenona. They typically present insidiously with claudication, however, uncommonly may present with acute limb ischaemia. We present a case of a young boy who presented with acute limb ischaemia secondary to osteochondroma with an intraoperative diagnosis of popliteal pseudoaneurysm. CASE REPORT: A 15-year-old male presented with an acutely ischaemic limb. A computed tomography CT angiogram was performed which demonstrated complete occlusion of his popliteal artery secondary to a tumour of the distal femur. The patient underwent an open biopsy of the tumour followed by thrombectomy which failed to resolve the ischaemia. After further unsuccessful attempts at thrombectomy, angiography was performed which revealed a pseudoaneurysm. . The patient underwent a successful popliteal exclusion bypass using ipsilateral reversed long saphenous vein. The lesion was subsequently identified as an osteochondroma. The patient made a good recovery and at his latest follow-up is ambulant, free from claudication, and demonstrates good flow through the bypass on duplex ultrasonography. CONCLUSION: Acute limb ischaemia is a rare occurrence within the adolescent population and will, therefore, frequently be secondary to an uncommon aetiology. Whilst While osteochondroma are is a common cause of vascular complications in this population, the onset of symptoms is usually more insidious. The acute onset, in this case, therefore, raised uncertainty as to the potential for malignancy. The management of these patients should involve a combination of both vascular and orthopaedic surgery in order to return perfusion whilest also ensuring the offending lesion is managed appropriately. In patients where initial measures do not restore perfusion, then the potential for further complications such as pseudoaneurysm should be considered and managed promptly.