Perioperative fluid management and outcomes in adult deceased donor liver transplantation - A systematic review of the literature and expert panel recommendations.

BACKGROUND: Fluid management practices during and after liver transplantation vary widely among centers despite better understanding of the pathophysiology of end-stage liver disease and of the effects of commonly used fluids. This reflects a lack of high quality trials in this setting, but also provides a rationale for both systematic review of all relevant studies in liver recipients and evaluation of new evidence from closely related domains, including hepatology, non-transplant abdominal surgery, and critical care. OBJECTIVES: To develop evidence-based recommendations for perioperative fluid management to optimize immediate and short-term outcomes following liver transplantation. DATA SOURCES: Ovid MEDLINE, Embase, Scopus, Google Scholar, and Cochrane Central. METHODS: Systematic review following PRISMA guidelines and recommendations using the GRADE approach derived from an international expert panel. Studies included those evaluating the following postoperative outcomes: acute kidney injury, respiratory complications, operative blood loss/red cell units required, and intensive care length of stay. PROSPERO protocol ID: CRD42021241392 RESULTS: Following expert panel review, 18 of 1624 screened studies met eligibility criteria for inclusion in the final quantitative synthesis. These included six single center RCTs, 11 single center observational studies, and one observational study comparing centers with different fluid management techniques. Definitions of interventions and outcomes varied between studies. Recommendations are therefore based substantially on expert opinion and evidence from other clinical settings. CONCLUSIONS: A moderately restrictive or "replacement only" fluid regime is recommended, especially during the dissection phase of the transplant procedure. Sustained hypervolemia, based on absence of fluid responsiveness, elevated filling pressures and/or echocardiographic findings, should be avoided (Quality of Evidence: Moderate | Grade of Recommendation: Weak for restrictive fluid regime. Strong for avoidance of hypervolemia). Mean Arterial Pressure (MAP) should be maintained at >60-65 mmHg in all cases (Quality of Evidence: Low | Grade of Recommendation: Strong). There is insufficient evidence in this population to support preferential use of any specific colloid or crystalloid for routine volume replacement. However, we recommend against the use of 130/.4 HES given the high incidence of AKI in this population.

Prehabilitation for Vascular Surgery Patients: Challenges and Opportunities.

Global demand for major surgery is rising as a consequence of a growing ageing population, and clinically applicable approaches to perioperative risk reduction have never been more needed. Prehabilitation aims to optimise aerobic capacity and address modifiable risk factors before surgery to improve postoperative outcomes. Given the inherently high-risk nature of vascular surgery and the frequently high-acuity frail vascular surgical population, the potential to introduce an intervention into the surgical pathway that may reduce postoperative complications cannot be overlooked. The aim of this review is to examine the current evidence base for prehabilitation in patients awaiting vascular surgery, and to summarise the potential benefits, pitfalls, and practicalities of this emerging perioperative intervention. There is a paucity of high-quality research specifically aimed at prehabilitation for patients undergoing vascular surgery, both peripheral and aortic, making it difficult to draw definitive conclusions upon which to base a change in practice. Currently, evidence is taken from small, often single-centre, heterogeneous studies that vary significantly from each other, meaning that the optimal exercise regimen for patients awaiting vascular surgery has yet to be defined. Establishing the impact of prehabilitation on outcomes for vascular patients is important as the effectiveness of preoperative exercise training is likely to vary between surgical interventions and patient populations. However, extrapolation from other cohorts is possible and indeed forms the basis of many current prehabilitation programmes. Given the success of prehabilitation in other surgical groups, it has potential to become an important future research target for patients awaiting vascular surgery.

An Outpatient Hospital-based Exercise Training Program for Patients With Cirrhotic Liver Disease Awaiting Transplantation: A Feasibility Trial.

BACKGROUND: Time spent on the waiting list before liver transplantation (LT) provides an opportunity to optimize recipient fitness through prehabilitation, potentially reducing the physiological impact of major surgery. We assessed the feasibility and effectiveness of a 6-week exercise program in patients with cirrhotic liver disease awaiting LT. METHODS: This single-center, prospective cohort, feasibility study, enrolled patients awaiting LT to a 6-week period of thrice weekly, supervised exercise on a static bike. Cardiopulmonary exercise testing (CPET) was used to objectively assess cardiopulmonary fitness at baseline and after 6 weeks of exercise. A follow-up CPET was performed at 12 weeks. CPET-derived measures were used to guide prescription of the training program. A nonrandomized control cohort of LT patients were selected to match the exercise group based on specific demographic data. Allocation to study arms was primarily based on the distance participants lived from the hospital where training occurred. Both groups received structured nutritional advice. RESULTS: The exercise program was feasible, with 9 of 16 (56%) patients completing the full program of 6 weeks. Peak oxygen consumption (VO2peak) in the exercise group rose from a mean (SD) of 16.2 (±3.4) mL/kg/min at baseline to 18.5 (±4.6) mL/kg/min at week 6 (P = 0.02). In the control group, VO2peak decreased from a mean (SD) of 19.0 (±6.1) mL/kg/min to 17.1 (±6.0) at week 6 (P = 0.03). CONCLUSIONS: We have demonstrated that it is feasible to engage patients awaiting LT in an intensive aerobic exercise program with a signal of improvement in fitness being detected.

Perioperative management of adult cadaveric and live donor renal transplantation in the UK: a survey of national practice.

BACKGROUND: There is a limited evidence base and no national consensus regarding the perioperative management of patients undergoing renal transplantation. We developed an electronic survey to capture an overview of renal transplant perioperative practice across UK renal transplant centres and determine the need for future guidelines on patient management. METHODS: A 29-question survey was developed to encompass the entire renal transplant perioperative pathway and input was sought from clinicians with expertise in renal transplant surgery, anaesthesia, nephrology and intensive care. The survey was sent to lead renal anaesthetists at each of the 23 transplant centres across the UK. RESULTS: A 96% response rate was achieved with 22 out of 23 centres returning complete responses. There was limited evidence of guideline-based approaches to preoperative workup. Questions regarding intraoperative fluid management, blood pressure targets, vasopressor administration and central venous pressure (CVP) monitoring identified a broad range of practice. Of note, the routine use of goal-directed fluid therapy based on cardiac output estimation was reported in six (27.3%) centres, while nine centres (40.9%) continue to target a specific CVP intraoperatively. In all, 12 (54.5%) centres perform transversus abdominis plane blocks with fentanyl-based patient-controlled analgesia as the most common mode of postoperative analgesia. A single centre reported a renal transplant-specific Enhanced Recovery after Surgery programme for cadaveric organ recipients. CONCLUSIONS: This questionnaire highlighted a high degree of heterogeneity in current UK practice as regards the perioperative management of renal transplant recipients. Development of evidence-based national consensus guidelines to standardize the perioperative care of these patients is recommended in order to improve patient outcomes and focus areas of future research.

Correction to: Intraoperative oxygenation in adult patients undergoing surgery (iOPS): a retrospective observational study across 29 UK hospitals.

[This corrects the article DOI: 10.1186/s13741-018-0098-3.].

Intraoperative oxygenation in adult patients undergoing surgery (iOPS): a retrospective observational study across 29 UK hospitals.

Background: Considerable controversy remains about how much oxygen patients should receive during surgery. The 2016 World Health Organization (WHO) guidelines recommend that intubated patients receive a fractional inspired oxygen concentration (FIO2) of 0.8 throughout abdominal surgery to reduce the risk of surgical site infection. However, this recommendation has been widely criticised by anaesthetists and evidence from other clinical contexts has suggested that giving a high concentration of oxygen might worsen patient outcomes. This retrospective multi-centre observational study aimed to ascertain intraoperative oxygen administration practice by anaesthetists across parts of the UK. Methods: Patients undergoing general anaesthesia with an arterial catheter in situ across hospitals affiliated with two anaesthetic trainee audit networks (PLAN, SPARC) were eligible for inclusion unless undergoing cardiopulmonary bypass. Demographic and intraoperative oxygenation data, haemoglobin saturation and positive end-expiratory pressure were retrieved from anaesthetic charts and arterial blood gases (ABGs) over five consecutive weekdays in April and May 2017. Results: Three hundred seventy-eight patients from 29 hospitals were included. Median age was 66 years, 205 (54.2%) were male and median ASA grade was 3. One hundred eight (28.6%) were emergency cases. An anticipated difficult airway or raised BMI was documented preoperatively in 31 (8.2%) and 45 (11.9%) respectively. Respiratory or cardiac comorbidity was documented in 103 (27%) and 83 (22%) respectively. SpO2 < 96% was documented in 83 (22%) patients, with 7 (1.9%) patients desaturating < 88% at any point intraoperatively. The intraoperative FIO2 ranged from 0.25 to 1.0, and median PaO2/FIO2 ratios for the first four arterial blood gases taken in each case were 24.6/0.5, 23.4/0.49, 25.7/0.46 and 25.4/0.47 respectively. Conclusions: Intraoperative oxygenation currently varies widely. An intraoperative FIO2 of 0.5 currently represents standard intraoperative practice in the UK, with surgical patients often experiencing moderate levels of hyperoxaemia. This differs from both WHO's recommendation of using an FIO2 of 0.8 intraoperatively, and also, the value most previous interventional oxygen therapy trials have used to represent standard care (typically FIO2 = 0.3). These findings should be used to aid the design of future intraoperative oxygen studies.

Should modulation of p50 be a therapeutic target in the critically ill?

INTRODUCTION: A defining feature of human hemoglobin is its oxygen binding affinity, quantified by the partial pressure of oxygen at which hemoglobin is 50% saturated (p50), and the variability of this parameter over a range of physiological and environmental states. Modulation of this property of hemoglobin can directly affect the degree of peripheral oxygen offloading and tissue oxygenation. Areas covered: This review summarizes the role of hemoglobin oxygen affinity in normal and abnormal physiology and discusses the current state of the literature regarding artificial modulation of p50. Hypoxic tumors, sickle cell disease, heart failure, and transfusion medicine are discussed in the context of recent advances in hemoglobin oxygen affinity manipulation. Expert commentary: Of particular clinical interest is the possibility of maintaining adequate end-organ oxygen availability in patients with anemia or compromised cardiac function via an increase in systemic p50. This increase in systemic p50 can be achieved with small molecule drugs or a packed red blood cell unit processing variant called rejuvenation, and human trials are needed to better understand the potential clinical benefits to modulating p50.

Pancreaticoduodenectomy for advanced duodenal and ampullary adenomatosis in familial adenomatous polyposis.

BACKGROUND: Patients with familial adenomatous polyposis (FAP) develop duodenal and ampullary polyps that may progress to malignancy via the adenoma-carcinoma sequence. OBJECTIVE: The aim of this study was to review a large series of FAP patients undergoing pancreaticoduodenectomy for advanced duodenal and ampullary polyposis. METHODS: A retrospective case notes review of all FAP patients undergoing pancreaticoduodenectomy for advanced duodenal and ampullary adenomatosis was performed. RESULTS: Between October 1993 and January 2010, 38 FAP patients underwent pancreaticoduodenectomy for advanced duodenal and ampullary polyps. Complications occurred in 29 patients and perioperative mortality in two. Postoperative histology revealed five patients to have preoperatively undetected cancer (R = 0.518, P < 0.001). CONCLUSIONS: Pancreaticoduodenectomy in FAP is associated with significant morbidity, but low mortality. All patients under consideration for operative intervention require careful preoperative counselling and optimization.