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Estimating intraoperative blood loss is one of the daily challenges for clinicians. Despite the knowledge of the inaccuracy of visual estimation by anaesthetists and surgeons, this is still the mainstay to estimate surgical blood loss. This review aims at highlighting the strengths and weaknesses of currently used measurement methods. A systematic review of studies on estimation of blood loss was carried out. Studies were included investigating the accuracy of techniques for quantifying blood loss in vivo and in vitro. We excluded nonhuman trials and studies using only monitoring parameters to estimate blood loss. A meta-analysis was performed to evaluate systematic measurement errors of the different methods. Only studies that were compared with a validated reference e.g. Haemoglobin extraction assay were included. 90 studies met the inclusion criteria for systematic review and were analyzed. Six studies were included in the meta-analysis, as only these were conducted with a validated reference. The mixed effect meta-analysis showed the highest correlation to the reference for colorimetric methods (0.93 95% CI 0.91–0.96), followed by gravimetric (0.77 95% CI 0.61–0.93) and finally visual methods (0.61 95% CI 0.40–0.82). The bias for estimated blood loss (ml) was lowest for colorimetric methods (57.59 95% CI 23.88–91.3) compared to the reference, followed by gravimetric (326.36 95% CI 201.65–450.86) and visual methods (456.51 95% CI 395.19–517.83). Of the many studies included, only a few were compared with a validated reference. The majority of the studies chose known imprecise procedures as the method of comparison. Colorimetric methods offer the highest degree of accuracy in blood loss estimation. Systems that use colorimetric techniques have a significant advantage in the real-time assessment of blood loss.
Background: Transfusion of red blood cells (RBC) in patients undergoing major elective cranial surgery is associated with increased morbidity, mortality and prolonged hospital length of stay (LOS). This retrospective single center study aims to identify the impact of RBC transfusions on skull-base and non-skull-base meningioma patients including the identification of risk factors for RBC transfusion.
Methods: From October 2009 - October 2016 we retrospectively analyzed 423 primary meningioma patients undergoing surgery for primary meningioma resection our department.
Results: Of these 423 patients, 68 (16.1%) received RBC transfusion and 355 (83.9%) did not receive RBC units. Preoperative anaemia rate was significantly higher in transfused patients (17.7%) compared to patients without RBC transfusion (6.2%; p = 0.0015). In transfused patients, postoperative complications as well as hospital LOS was significantly higher (p < 00001) compared to non-transfused patients. After multivariate analyses, risk factors for RBC transfusion were preoperative American Society of Anesthesiologists (ASA) physical status score (p = 0.0247), tumor size (p = 0.0006), surgical time (p = 0.0018) and intraoperative blood loss (p < 0.001). Kaplan-Meier curves revealed significant influence on overall survival by preoperative anaemia, RBC transfusion, smoking, cardiovascular disease, preoperative KPS ≤ 60% and age (elderly ≥ 75 years).
Conclusion: We concluded that blood loss due to large tumors or localization near large vessels are the main triggers for RBC transfusion in meningioma patients paired with a potential preselection that masks the effect of preoperative anaemia in multivariate analysis. Further studies evaluating the impact of preoperative anaemia management for reduction of RBC transfusion are needed to improve clinical outcomes of meningioma patients.
Purpose: Anaemia is one of the leading causes of death among severely injured patients. It is also known to increase the risk of death and prolong the length of hospital stay in various surgical groups. The main objective of this study is to analyse the anaemia rate on admission to the emergency department and the impact of anaemia on in-hospital mortality.
Methods: Data from the TraumaRegister DGU® (TR-DGU) between 2015 and 2019 were analysed. Inclusion criteria were age ≥ 16 years and most severe Abbreviated Injury Scale (AIS) score ≥ 3. Patients were divided into three anaemia subgroups: no or mild anaemia (NA), moderate anaemia (MA) and severe anaemia (SA). Pre-hospital data, patient characteristics, treatment in the emergency room (ER), outcomes, and differences between trauma centres were analysed.
Results: Of 67,595 patients analysed, 94.9% (n = 64,153) exhibited no or mild anaemia (Hb ≥ 9 g/dl), 3.7% (n = 2478) displayed moderate anaemia (Hb 7–8 g/dl) and 1.4% (n = 964) presented with severe anaemia (Hb < 7 g/dl). Haemoglobin (Hb) values ranged from 3 to 18 g/dl with a mean Hb value of 12.7 g/dl. In surviving patients, anaemia was associated with prolonged length of stay (LOS). Multivariate logistic regression analyses revealed moderate (p < 0.001 OR 1.88 (1.66–2.13)) and severe anaemia (p < 0.001 OR 4.21 (3.46–5.12)) to be an independent predictor for mortality. Further significant predictors are ISS score per point (OR 1.0), age 70–79 (OR 4.8), age > 80 (OR 12.0), severe pre-existing conditions (ASA 3/4) (OR 2.26), severe head injury (AIS 5/6) (OR 4.8), penetrating trauma (OR 1.8), unconsciousness (OR 4.8), shock (OR 2.2) and pre-hospital intubation (OR 1.6).
Conclusion: The majority of severely injured patients are admitted without anaemia to the ER. Injury-associated moderate and severe anaemia is an independent predictor of mortality in severely injured patients.
Introduction: Cell salvage (CS) is an integral part of patient blood management (PBM) and aims to reduce allogeneic red blood cell (RBC) transfusion.
Material and methods: This observational study analysed patients scheduled for elective cardiac surgery requiring cardiopulmonary bypass (CPB) between November 2015 and October 2018. Patients were divided into a CS group (patients receiving CS) and a control group (no CS). Primary endpoints were the number of patients exposed to allogeneic RBC transfusions and the number of RBC units transfused per patient.
Results: A total of 704 patients undergoing cardiac surgery were analysed, of whom 338 underwent surgery with CS (CS group) and 366 were without CS (control group). Intraoperatively, 152 patients (45%) were exposed to allogeneic RBC transfusions in the CS group and 93 patients (25%) in the control group (P < 0.001). Considering the amount of intraoperative blood loss, regression analysis revealed a significant association between blood loss and increased use of RBC units in patients of the control compared to the CS group (1000 mL: 1.0 vs. 0.6 RBC units; 2000 mL: 2.2 vs. 1.1 RBC units; 3000 mL: 3.4 vs. 1.6 RBC units). Thus, CS was significantly associated with a reduced number of allogeneic RBCs by 40% for 1000 mL, 49% for 2000 mL, and 52% for 3000 mL of blood loss compared to patients without CS.
Conclusions: Cell salvage was significantly associated with a reduced number of allogeneic RBC transfusions. It supports the beneficial effect of CS in cardiac surgical patients as an individual measure in a comprehensive PBM program.
Background: The most common technique used worldwide to quantify blood loss during an operation is the visual assessment by the attending intervention team. In every operating room you will find scaled suction canisters that collect fluids from the surgical field. This scaling is commonly used by clinicians for visual assessment of intraoperative blood loss. While many studies have been conducted to quantify and improve the inaccuracy of the visual estimation method, research has focused on the estimation of blood volume in surgical drapes. The question whether and how scaling of canisters correlates with actual blood loss and how accurately clinicians estimate blood loss in scaled canisters has not been the focus of research to date.
Methods: A simulation study with four “bleeding” scenarios was conducted using expired whole blood donations. After diluting the blood donations with full electrolyte solution, the sample blood loss volume (SBL) was transferred into suction canisters. The study participants then had to estimate the blood loss in all four scenarios. The difference to the reference blood loss (RBL) per scenario was analyzed.
Results: Fifty-three anesthetists participated in the study. The median estimated blood loss was 500 ml (IQR 300/1150) compared to the RBL median of 281.5 ml (IQR 210.0/1022.0). Overestimations up to 1233 ml were detected. Underestimations were also observed in the range of 138 ml. The visual estimate for canisters correlated moderately with RBL (Spearman’s rho: 0.818; p < 0.001). Results from univariate nonparametric confirmation statistics regarding visual estimation of canisters show that the deviation of the visual estimate of blood loss is significant (z = − 10.95, p < 0.001, n = 220). Participants’ experience level had no significant influence on VEBL (p = 0.402).
Conclusion: The discrepancies between the visual estimate of canisters and the actual blood loss are enormous despite the given scales. Therefore, we do not recommend estimating the blood loss visually in scaled suction canisters. Colorimetric blood loss estimation could be a more accurate option.
Background: Approximately one in three patients suffers from preoperative anaemia. Even though haemoglobin is measured before surgery, anaemia management is not implemented in every hospital. Objective: Here, we demonstrate the implementation of an anaemia walk-in clinic at an Orthopedic University Hospital. To improve the diagnosis of iron deficiency (ID), we examined whether reticulocyte haemoglobin (Ret-He) could be a useful additional parameter. Material and Methods: In August 2019, an anaemia walk-in clinic was established. Between September and December 2019, major orthopaedic surgical patients were screened for preoperative anaemia. The primary endpoint was the incidence of preoperative anaemia. Secondary endpoints included Ret-He level, red blood cell (RBC) transfusion rate, in-hospital length of stay and anaemia at hospital discharge. Results: A total of 104 patients were screened for anaemia. Preoperative anaemia rate was 20.6%. Intravenous iron was supplemented in 23 patients. Transfusion of RBC units per patient (1.7 ± 1.2 vs. 0.2 ± 0.9; p = 0.004) and hospital length of stay (13.1 ± 4.8 days vs. 10.6 ± 5.1 days; p = 0.068) was increased in anaemic patients compared to non-anaemic patients. Ret-He values were significantly lower in patients with ID anaemia (33.3 pg [28.6–40.2 pg]) compared to patients with ID (35.3 pg [28.9–38.6 pg]; p = 0.015) or patients without anaemia (35.4 pg [30.2–39.4 pg]; p = 0.001). Conclusion: Preoperative anaemia is common in orthopaedic patients. Our results proved the feasibility of an anaemia walk-in clinic to manage preoperative anaemia. Furthermore, our analysis supports the use of Ret-He as an additional parameter for the diagnosis of ID in surgical patients.
Background: Iron deficiency (ID) is one of the most common nutritional deficiencies in children worldwide and may result in iron deficiency anemia (IDA). The reticulocyte hemoglobin equivalent (Ret-He) provides information about the current availability of iron in erythropoiesis. This study aims to examine the validation of Ret-He as a screening marker for ID and IDA in children. Methods: Blood samples were retrospectively obtained from medical records. Anemia was defined according to the definition provided by the World Health Organization (WHO) for children. ID was defined by transferrin saturation (TSAT) < 20% and ferritin < 100 ng/mL. Children were classified into four groups: IDA, non-anemia iron deficiency (NAID), control and others. Results: Out of 970 children, 332 (34.2%) had NAID and 278 (28.7%) presented with IDA. Analysis revealed that Ret-He significantly correlates with ferritin (rho = 0.41; p < 0.001), TSAT (rho = 0.66; p < 0.001) and soluble transferrin receptor (sTfR) (rho = −0.72; p < 0.001). For ROC analysis, the area under the curve (AUC) was 0.771 for Ret-He detecting ID and 0.845 for detecting IDA. The cut-off value for Ret-He to diagnose ID was 33.5 pg (sensitivity 90.7%; specificity 35.8%) and 31.6 pg (sensitivity 90.6%; specificity 50.4%) to diagnose IDA. Conclusions: The present study demonstrates Ret-He to be a screening marker for ID and IDA in children. Furthermore, Ret-He can be used as a single screening parameter for ID and IDA in children without considering other iron parameters. Economically, the use of Ret-He is highly relevant, as it can save one blood tube per patient and additional costs.
Local anesthetics are commonly administered by nuchal infiltration to provide a temporary interscalene brachial plexus block (ISB) in a surgical setting. Although less commonly reported, local anesthetics can induce central nervous system toxicity. In this case study, we present three patients with acute central nervous system toxicity induced by local anesthetics applied during ISB with emphasis on neurological symptoms, key neuroradiological findings and functional outcome. Medical history, clinical and imaging findings, and outcome of three patients with local anesthetic-induced toxic left hemisphere syndrome during left ISB were analyzed. All patients were admitted to our neurological intensive care unit between November 2016 and September 2019. All three patients presented in poor clinical condition with impaired consciousness and left hemisphere syndrome. Electroencephalography revealed slow wave activity in the affected hemisphere of all patients. Seizure activity with progression to status epilepticus was observed in one patient. In two out of three patients, cortical FLAIR hyperintensities and restricted diffusion in the territory of the left internal carotid artery were observed in magnetic resonance imaging. Assessment of neurological severity scores revealed spontaneous partial reversibility of neurological symptoms. Local anesthetic-induced CNS toxicity during ISB can lead to severe neurological impairment and anatomically variable cerebral lesions.