Intraoperative Blood Management Strategies for Patients Undergoing Noncardiac Surgery: The Ottawa Intraoperative Transfusion Consensus.

Importance: There is marked variability in red blood cell (RBC) transfusion during the intraoperative period. The development and implementation of existing clinical practice guidelines have been ineffective in reducing this variability. Objective: To develop an internationally endorsed consensus statement about intraoperative transfusion in major noncardiac surgery. Evidence Review: A Delphi consensus survey technique with an anonymous 3-round iterative rating and feedback process was used. An expert panel of surgeons, anesthesiologists, and transfusion medicine specialists was recruited internationally. Statements were informed by extensive preparatory work, including a systematic reviews of intraoperative RBC guidelines and clinical trials, an interview study with patients to explore their perspectives about intraoperative transfusion, and interviews with physicians to understand the various behaviors that influence intraoperative transfusion decision-making. Thirty-eight statements were developed addressing (1) decision-making (interprofessional communication, clinical factors, procedural considerations, and audits), (2) restrictive transfusion strategies, (3) patient-centred considerations, and (4) research considerations (equipoise, outcomes, and protocol suspension). Panelists were asked to score statements on a 7-point Likert scale. Consensus was established with at least 75% agreement. Findings: The 34-member expert panel (14 of 33 women [42%]) included 16 anesthesiologists, 11 surgeons, and 7 transfusion specialists; panelists had a median of 16 years' experience (range, 2-50 years), mainly in Canada (52% [17 of 33]), the US (27% [9 of 33]), and Europe (15% [5 of 33]). The panel recommended routine preoperative and intraoperative discussion between surgeons and anesthesiologists about intraoperative RBC transfusion as well as postoperative review of intraoperative transfusion events. Point-of-care hemoglobin testing devices were recommended for transfusion guidance, alongside an algorithmic transfusion protocol with a restrictive hemoglobin trigger; however, more research is needed to evaluate the use of restrictive triggers in the operating room. Expert consensus recommended a detailed preoperative consent discussion with patients of the risks and benefits of both anemia and RBC transfusion and routine disclosure of intraoperative transfusion. Postoperative morbidity and mortality were recommended as the most relevant outcomes associated with intraoperative RBC transfusion, and transfusion triggers of 70 and 90 g/L were considered acceptable hemoglobin triggers to evaluate restrictive and liberal transfusion strategies, respectively, in clinical trials. Conclusions and Relevance: This consensus statement offers internationally endorsed expert guidance across several key domains on intraoperative RBC transfusion practice for noncardiac surgical procedures for which patients are at medium or high risk of bleeding. Future work should emphasize knowledge translation strategies to integrate these recommendations into routine clinical practice and transfusion research activities.

Point-of-care haemoglobin accuracy and transfusion outcomes in non-cardiac surgery at a Canadian tertiary academic hospital: protocol for the PREMISE observational study.

INTRODUCTION: Transfusions in surgery can be life-saving interventions, but inappropriate transfusions may lack clinical benefit and cause harm. Transfusion decision-making in surgery is complex and frequently informed by haemoglobin (Hgb) measurement in the operating room. Point-of-care testing for haemoglobin (POCT-Hgb) is increasingly relied on given its simplicity and rapid provision of results. POCT-Hgb devices lack adequate validation in the operative setting, particularly for Hgb values within the transfusion zone (60-100 g/L). This study aims to examine the accuracy of intraoperative POCT-Hgb instruments in non-cardiac surgery, and the association between POCT-Hgb measurements and transfusion decision-making. METHODS AND ANALYSIS: PREMISE is an observational prospective method comparison study. Enrolment will occur when adult patients undergoing major non-cardiac surgery require POCT-Hgb, as determined by the treating team. Three concurrent POCT-Hgb results, considered as index tests, will be compared with a laboratory analysis of Hgb (lab-Hgb), considered the gold standard. Participants may have multiple POCT-Hgb measurements during surgery. The primary outcome is the difference in individual Hgb measurements between POCT-Hgb and lab-Hgb, primarily among measurements that are within the transfusion zone. Secondary outcomes include POCT-Hgb accuracy within the entire cohort, postoperative morbidity, mortality and transfusion rates. The sample size is 1750 POCT-Hgb measurements to obtain a minimum of 652 Hgb measurements <100 g/L, based on an estimated incidence of 38%. The sample size was calculated to fit a logistic regression model to predict instances when POCT-Hgb are inaccurate, using 4 g/L as an acceptable margin of error. ETHICS AND DISSEMINATION: Institutional ethics approval has been obtained by the Ottawa Health Science Network-Research Ethics Board prior to initiating the study. Findings from this study will be published in peer-reviewed journals and presented at relevant scientific conferences. Social media will be leveraged to further disseminate the study results and engage with clinicians.

Phlebotomy resulting in controlled hypovolemia to prevent blood loss in major hepatic resections (PRICE-2): study protocol for a phase 3 randomized controlled trial.

INTRODUCTION: Blood loss and red blood cell (RBC) transfusion in liver surgery are areas of concern for surgeons, anesthesiologists, and patients alike. While various methods are employed to reduce surgical blood loss, the evidence base surrounding each intervention is limited. Hypovolemic phlebotomy, the removal of whole blood from the patient without volume replacement during liver transection, has been strongly associated with decreased bleeding and RBC transfusion in observational studies. This trial aims to investigate whether hypovolemic phlebotomy is superior to usual care in reducing RBC transfusions in liver resection. METHODS: This study is a double-blind multicenter randomized controlled trial. Adult patients undergoing major hepatic resections for any indication will be randomly allocated in a 1:1 ratio to either hypovolemic phlebotomy and usual care or usual care alone. Exclusion criteria will be minor resections, preoperative hemoglobin <100g/L, renal insufficiency, and other contraindication to hypovolemic phlebotomy. The primary outcome will be the proportion of patients receiving at least one allogeneic RBC transfusion unit within 30 days of the onset of surgery. Secondary outcomes will include transfusion of other allogeneic blood products, blood loss, morbidity, mortality, and intraoperative physiologic parameters. The surgical team will be blinded to the intervention. Randomization will occur on the morning of surgery. The sample size will comprise 440 patients. Enrolment will occur at four Canadian academic liver surgery centers over a 4-year period. Ethics approval will be obtained at participating sites before enrolment. DISCUSSION: The results of this randomized control trial will provide high-quality evidence regarding the use of hypovolemic phlebotomy in major liver resection and its effects on RBC transfusion. If proven to be effective, this intervention could become standard of care in liver operations internationally and become incorporated within perioperative patient blood management programs. TRIAL REGISTRATION: ClinicalTrials.gov NCT03651154 . Registered on August 29 2018.

Treatment of Frostbite With Hyperbaric Oxygen Therapy: A Single Center's Experience of 22 Cases.

INTRODUCTION: Frostbite is well documented in the military and countries with extreme temperatures, and it is most likely due to increased exposure to cold temperatures and/or risk-taking behavior. Severity of injury depends on absolute temperature, wind chill, duration of exposure, wet or dry cold, immersion, clothing quality, and substance use. Hyperbaric oxygen therapy (HBOT) has been described as a treatment option but only in small case series. OBJECTIVE: The aim of this retrospective study is to describe the usage patterns, side effects, and outcomes of HBOT used as an adjunct to wound care at a single major Canadian university hospital. MATERIALS AND METHODS: A retrospective review of patients with frostbite injury admitted and treated with HBOT between January 2000 and March 2015 was performed. A total of 22 patients were studied. Available data included patient demographics, duration of exposure to cold temperature, severity of injury, time to HBOT, duration of therapy, side effects of therapy, concurrent therapies (dressing, anticoagulation, antibiotics), bone scan results, and consequent level of amputation. RESULTS: The cohort consisted mostly of men (18, 81.8%) and patient mean age of 40 years (range, 13-70 years). Ten patients (45.5%) were intoxicated at the time of injury, and psychiatric illness was implicated in 9 (40.9%) patients. Of the presented injuries, 17 (77.3%) had frostbite to the upper extremity. Bone scans were performed on 16 (72.7%) patients. In 4 patients, the absence of radiotracer activity correlated with a protective effect on subsequent amputation levels. All patients received anticoagulant therapy. Of the 22 patients, 16 (72.7%) experienced at least 1 side effect of HBOT, including otologic barotrauma, nausea, vomiting, anxiety, oxygen toxicity seizure, and myopic changes. All study patients recovered without permanent sequelae; it is unclear whether HBOT reduced soft-tissue damage or amputation rates. CONCLUSIONS: This is the largest cohort reported in the literature of patients with frostbite injuries treated with HBOT. Hyperbaric oxygen therapy may show positive impact on the demarcation level of frostbite and, despite the common side effects, it generally causes no long-term sequelae.

Hypovolemic phlebotomy in liver surgery is associated with decreased red blood cell transfusion.

BACKGROUND: Perioperative red blood cell (RBC) transfusion is associated with poor outcomes in liver surgery. Hypovolemic phlebotomy (HP) is a novel intervention hypothesized to decrease transfusion requirements. The objective of this study was to examine this hypothesis. METHODS: Consecutive patients who underwent liver resection at one institution (2010-2016) were included. Factors found to be predictive of transfusion on univariate analysis and those previously published were modeled using multivariate logistic regression. RESULTS: A total of 361 patients underwent liver resection (50% major). HP was performed in 45 patients. Phlebotomized patients had a greater proportion of primary malignancy (31% vs 18%) and major resection (84% vs 45%). Blood loss was significantly lower with phlebotomy in major resections (400 vs 700 mL). Nadir central venous pressure was significantly lower with HP (2.5 vs 5 cm H2O). On multivariate logistic regression, HP (OR 0.20, 95% CI 0.068-0.57, p = 0.0029), major liver resection (OR 2.91, 95% CI 1.64-5.18, p = 0.0003), preoperative hemoglobin < 125 g/L (OR 6.02, 95% CI 3.44-10.56, p < 0.0001), and underlying liver disease (OR 2.24, 95% CI 1.27-3.95, p = 0.0051) were significantly associated with perioperative RBC transfusion. CONCLUSION: Hypovolemic phlebotomy appears to be strongly associated with a reduction in RBC transfusion requirements in liver resection, independent of other known risk factors.

Safety and feasibility of phlebotomy with controlled hypovolemia to minimize blood loss in liver resections.

BACKGROUND: Liver resection can be associated with significant blood loss and transfusion. Whole blood phlebotomy is an under-reported technique, distinct from acute normovolemic hemodilution, the goal of which is to minimize blood loss in liver operation. This work sought to report on its safety and feasibility and to describe technical considerations. METHODS: Consecutive patients who had an elective liver resection and concurrent phlebotomy between 2013 and 2016 were examined prospectively. Formal Inclusion and exclusion criteria were defined a priori. All surgical indications were allowed. All procedures were carried out with a stated goal of low central venous pressure anesthesia (<5 cm H2O). The target phlebotomy volume was 7-10 mL/kg of patient body weight. The removed blood was not replaced by intravenous fluid. Removed blood was returned back to the patient after parenchymal transection. Safety end points were examined. A historic cohort (2010-2014) of major resections was included for comparison. RESULTS: A total of 37 patients underwent liver resection with phlebotomy (86% major) and 101 without. Half had metastatic colorectal cancer. The median phlebotomy volume was 7.2 mg/kg (4.7-10.2), yielding a median drop in central venous pressure of 3 cm H2O (0-15). Median blood loss was 400 vs 700 mL (P = .0016), and the perioperative transfusion rate was 8.1% vs 32% (P = .0048). There was no difference between the 2 groups in overall complications, mortality, intensive care admission, duration of stay, or end-organ ischemic complications. CONCLUSION: Whole blood phlebotomy with controlled hypovolemia prior to liver resection seems to be safe and feasible. Comparative studies are required to determine its effectiveness.

Cognitive dysfunction after total knee arthroplasty: effects of intraoperative cerebral embolization and postoperative complications.

Cerebral emboli identified as high-intensity transient signals (HITS) occur during total knee arthroplasty (TKA). Their effects on cognitive outcome remain speculative. Intraoperative HITS and postoperative complications were correlated with the cognitive function of TKA patients. Cognitive function was assessed both before and after surgery (1 week and 3 months). High-intensity transient signals occurred in 22 of 37 patients. Counts of HITSs were higher in patients with sonographically detected intracardiac shunts. Cognitive dysfunction was found in 41% of patients at 1 week, but in only 18% at 3 months. High-intensity transient signal counts were not associated with the prevalence of cognitive deficits. At 1 week, 58% of patients with cognitive deficits had at least 1 postoperative complication (6% in nondeficit patients). All cognitively impaired patients at 3 months had complications (17% in the nondeficit group). This raises the possibility that postoperative complications might be associated with cognitive dysfunction in TKA patients.