Maternal outcomes following postpartum autotransfusion of blood lost during vaginal obstetric hemorrhage.

BACKGROUND: Autotransfusion following vaginal delivery has not been as widely adopted and existing data on this topic are limited to small case series. METHODS: This is a single-center retrospective matched cohort study. Deliveries exposed to autotransfusion during obstetric hemorrhage were matched to unexposed controls with obstetric hemorrhage who did not receive autotransfusion. The primary outcome was allogeneic transfusion of packed red blood cells. Planned secondary analyses included change in hemoglobin following delivery, composite maternal safety outcomes, and unplanned postpartum health care utilization. RESULTS: Thirty-six deliveries exposed to autotransfusion were matched to 144 unexposed controls. There was no significant difference in allogenic transfusion of packed red blood cells in the patients exposed to autotransfusion red with unexposed controls (adjusted OR 1.1; 95% CI 0.5-2.4). Deliveries that received autotransfusion had a less severe pre- to post-delivery decline in hemoglobin compared with unexposed controls across all values of QBL (p = .003). There were no significant differences in maternal morbidity outcomes evaluated in exposed versus unexposed deliveries. CONCLUSION: Autotransfusion in cases of vaginal obstetric hemorrhage did not attenuate rates of allogenic packed red blood cell transfusion but did result in a less severe pre- to postdelivery decline in hemoglobin at discharge. Autotransfusion cases did not have any markers of increased maternal morbidity when compared with a control group. These findings support emerging evidence indicating that autotransfusion of blood lost during vaginal obstetric hemorrhage is a safe and potentially effective tool for use in the management of obstetric hemorrhage.

Autotransfusion of vaginally shed blood as a novel therapy in obstetric hemorrhage: A case series.

OBJECTIVE: To report maternal outcomes in a cohort of women who received autotransfusion of vaginally shed blood and to describe the feasibility of blood collection and cell salvage processing at the time of vaginal hemorrhage. STUDY DESIGN AND METHODS: We conducted a retrospective case series of patients who received autotransfusion of vaginally shed blood at the time of obstetric hemorrhage from January 2014 to August 2020. Maternal data and cell salvage utilization characteristics were abstracted from the electronic medical record. RESULTS: Sixty-four cases were identified in which autotransfusion of vaginally shed blood occurred during an obstetric hemorrhage. Median quantitative blood loss was 2175 ml (interquartile range 1500-2250 ml) with 89% of cases having a blood loss greater than 1000 ml. Patients on average received approximately 1.3 units of autologous blood product (384 ml, interquartile range 244-520 ml) and no direct adverse events were observed during transfusion. We observed heterogeneity in autologous blood volume across all values of quantitative blood loss. The need for allogenic blood transfusion was common and occurred in 72% of all cases (N = 46). There were no documented cases of maternal sepsis or severe infectious morbidity. CONCLUSION: In 64 cases where autotransfusion of vaginally shed blood occurred, autotransfusion was well tolerated. Heterogeneity in autologous blood volume collection likely represents the lack of standardized protocols for blood collection in the delivery room. Autotransfusion of vaginally shed blood is a feasible and reasonable technique to employ during severe obstetric hemorrhage.

How do I perform cell salvage during vaginal obstetric hemorrhage?

BACKGROUND: Obstetric hemorrhage is a leading cause of preventable maternal mortality. To combat this, obstetric organizations worldwide recommend consideration of autotransfusion during severe peripartum bleeding to minimize allogenic transfusion. Current guidelines for autotransfusion in obstetrics are limited to patients undergoing cesarean birth. At present, women experiencing vaginal obstetric hemorrhage are excluded from many obstetric autotransfusion protocols. However, emerging data suggest that autotransfusion of vaginally shed blood is both safe and feasible in the obstetric patient population. METHODS AND MATERIALS: In this review, we will provide an overview of the current literature surrounding cell salvage of vaginally send blood and a detailed outline of our institution's blood collection protocol. RESULTS: Recent data suggests autotransfusion of vaginally shed blood is both safe and effective. DISCUSSION: Implementation of autotransfusion technology into the delivery room is a critical next step for the advancement of transfusion medicine in obstetrics. This review provides an overview of the data surrounding autotransfusion of vaginally shed blood during maternal hemorrhage and describes practical suggestions for how it can be effectively implemented into routine practice.

Placenta Accreta Spectrum Disorders: Knowledge Gaps in Anesthesia Care.

Placenta accreta spectrum (PAS) disorder is a potentially life-threatening condition that can occur during pregnancy. PAS puts pregnant individuals at a very high risk of major blood loss, hysterectomy, and intensive care unit admission. These patients should receive care in a center with multidisciplinary experience and expertise in managing PAS disorder. Obstetric anesthesiologists play vital roles in the peripartum care of pregnant patients with suspected PAS. As well as providing high-quality anesthesia care, obstetric anesthesiologists coordinate peridelivery care, drive transfusion-related decision making, and oversee postpartum analgesia. However, there are a number of key knowledge gaps related to the anesthesia care of these patients. For example, limited data are available describing optimal anesthesia staffing models for scheduled and unscheduled delivery. Evidence and consensus are lacking on the ideal surgical location for delivery; primary mode of anesthesia for cesarean delivery; preoperative blood ordering; use of pharmacological adjuncts for hemorrhage management, such as tranexamic acid and fibrinogen concentrate; neuraxial blocks and abdominal wall blocks for postoperative analgesia; and the preferred location for postpartum care. It is also unclear how anesthesia-related decision making and interventions impact physical and mental health outcomes. High-quality international multicenter studies are needed to fill these knowledge gaps and advance the anesthesia care of patients with PAS.

Safety of Intraoperative Cell Salvage in Cancer Surgery: An Updated Meta-Analysis of the Current Literature.

Background: Allogeneic blood transfusions in oncologic surgery are associated with increased recurrence and mortality. Adverse effects on outcome could be reduced or avoided by using intraoperative autologous blood cell salvage (IOCS). However, there are concerns regarding the safety of the autologous IOCS blood. Previous meta-analyses from 2012 and 2020 did not identify increased risk of cancer recurrence after using autologous IOCS blood. The objective of this review was to reassess a greater number of IOCS-treated patients to present an updated and more robust analysis of the current literature. Methods: This systematic review includes full-text articles listed in PubMed, Cochrane, Cochrane Reviews, and Web of Science. We analyzed publications that discussed cell salvage or autotransfusion combined with the following outcomes: cancer recurrence, mortality, survival, allogeneic transfusion rate and requirements, length of hospital stay (LOS). To rate the strength of evidence, a Grading of Recommendations Assessment, Development and Evaluation (GRADE) of the underlying evidence was applied. Results: In the updated meta-analysis, 7 further observational studies were added to the original 27 observational studies included in the former 2020 analysis. Studies compared either unfiltered (n = 2,311) or filtered (n = 850) IOCS (total n = 3,161) versus non-IOCS use (n = 5,342). Control patients were either treated with autologous predonated blood (n = 484), with allogeneic transfusion (n = 4,113), or did not receive a blood transfusion (n = 745). However, the current literature still contains only observational studies on these topics, and the strength of evidence remains low. The risk of cancer recurrence was reduced in recipients of autologous salvaged blood with or without LDF (odds ratio [OR] 0.76, 95% confidence interval [CI]: 0.64-0.90) compared to nontransfused patients or patients with allogeneic transfusion. There was no difference in mortality (OR 0.95, 95% CI: 0.71-1.27) and LOS (mean difference -0.07 days, 95% CI: -0.63 to 0.48) between patients treated with IOCS blood or those in whom IOCS was not used. Due to high heterogeneity, transfusion rates or volumes could not be analyzed. Conclusion: Randomized controlled trials comparing mortality and cancer recurrence rate of IOCS with or without LDF filtration versus allogeneic blood transfusion were not found. Outcome was similar or better in patients receiving IOCS during cancer surgery compared to patients with allogeneic blood transfusion or nontransfused patients.

Improvements and limitations in developing multivariate models of hemorrhage and transfusion risk for the obstetric population.

BACKGROUND: Maternal hemorrhage protocols involve risk screening. These protocols prepare clinicians for potential hemorrhage and transfusion in individual patients. Patient-specific estimation and stratification of risk may improve maternal outcomes. STUDY DESIGN AND METHODS: Prediction models for hemorrhage and transfusion were trained and tested in a data set of 74 variables from 63 973 deliveries (97.6% of the source population of 65 560 deliveries included in a perinatal database from an academic urban delivery center) with sufficient data at pertinent time points: antepartum, peripartum, and postpartum. Hemorrhage and transfusion were present in 6% and 1.6% of deliveries, respectively. Model performance was evaluated with the receiver operating characteristic (ROC), precision-recall curves, and the Hosmer-Lemeshow calibration statistic. RESULTS: For hemorrhage risk prediction, logistic regression model discrimination showed ROCs of 0.633, 0.643, and 0.661 for the antepartum, peripartum, and postpartum models, respectively. These improve upon the California Maternal Quality Care Collaborative (CMQCC) accuracy of 0.613 for hemorrhage. Predictions of transfusion resulted in ROCs of 0.806, 0.822, and 0.854 for the antepartum, peripartum, and postpartum models, respectively. Previously described and new risk factors were identified. Models were not well calibrated with Hosmer-Lemeshow statistic P values between .001 and .6. CONCLUSIONS: Our models improve on existing risk assessment; however, further enhancement might require the inclusion of more granular, dynamic data. With the goal of increasing translatability, this work was distilled to an online open-source repository, including a form allowing risk factor inputs and outputs of CMQCC risk, alongside our numerical risk estimation and stratification of hemorrhage and transfusion.

Cell salvage in trauma.

PURPOSE OF REVIEW: The collection of shed blood and its reinfusion has been termed 'cell salvage' or 'autotransfusion'. This review will summarize the historical foundation of cell salvage and summarize recent literature associated with cell salvage use in trauma. RECENT FINDINGS: There have been no publications on cell salvage in trauma during the last 2 years. This is based on a PubMed search using the key words, 'cell salvage', 'autologous blood transfusion' and 'operative blood salvage'. Although the wars in Iraq and Afghanistan were ongoing, publications focused upon autotranfusion of unwashed blood from the hemothorax and on the resuscitation of the injured in remote settings. SUMMARY: Autotransfusion or cell salvage is markedly under utilized in trauma. Opportunities exist for significant blood savings if it is used more frequently. More research is clearly needed to assess the safety of autotransfusion in the traumatized patient.

The role of viscoelastic testing in the management of the parturient.

Viscoelastic testing is the measurement of how the viscoelastic properties of blood change as blood clots. In pregnancy, unique changes in clotting function occur overall to make the pregnant woman hypercoagulable. Viscoelastic testing may be able to play a role in guiding placement of epidural and spinal anesthetics by demonstrating enhanced coagulation function, even when there are individual parts of the coagulation system that are abnormal, for example, thrombocytopenia. These tools may also play a role in addressing the management of maternal hemorrhage, which in the United States is on the rise. This review discusses the opportunity to use viscoelastic testing in the parturient.

Impact of intrauterine transfusion on fetal coagulation physiology by thromboelastography.

OBJECTIVE: Thromboelastography (TEG) is a point-of-care device used to evaluate whole blood coagulation function. The TEG is unique as a test of coagulation function in that it measures the interaction of all components of clot formation, which is different than traditional laboratory-based tests that measure isolated components of coagulation. Little is known about fetal coagulation physiology. We sought to evaluate the impact of severe fetal anemia and intrauterine transfusion (IUT) on fetal coagulation physiology by use of the TEG and to compare fetal TEG values to those of healthy neonates and adults. METHOD: One milliliter of fetal blood was collected immediately before (pre) and after (post) IUT of packed red blood cells (PRBCs). Sampling and transfusion were performed for fetal anemia due to hemolytic disease of the fetus and newborn. Samples were run in duplicate. For descriptive summary, duplicate pre-IUT and post-IUT values were averaged. Values for R (initiation of clot in minutes), K (clot firmness in minutes), angle (kinetics of clot development in degrees), and MA (maximum strength in mm) were obtained for each sample and presented using mean ± SE. Pre-IUT values for R, K, angle, and MA were compared with post-IUT values using linear mixed-effect model to account for clustering due to repeated observation from the same fetus. Pre-IUT values are compared with normal healthy term neonates and healthy adults using Wald test. The study was approved by the University of Pittsburgh Institutional Review Board (PRO14050051). RESULTS: Four fetuses underwent nine IUTs rendering 17 pre-IUT and 17 post-IUT specimens. The mean gestational age at IUT was 31 weeks 2 days (25 weeks 4 days to 35 weeks 2 days). The mean IUT volume transfused was 69 mL (30-170 mL). The mean estimated percent intravascular volume transfused was 33.4% (19%-52%). Of the four variables analyzed, only R showed a significant difference, with the initiation of clot formation being modestly delayed after transfusion by an estimated 2.87 minutes (95% CI, 0.82-4.92, P = .0480). Pre-IUT values were compared with 100 normal term neonates and 118 healthy adults. Compared with pre-IUT, only R was affected (shorter) compared with term neonates (mean ± SE = 5.46 ± 0.16 minute, P < .001) and healthy adults (mean ± SE = 6.8 ± 0.13 minute, P < .001). CONCLUSION: OTHER THAN A MODEST PROLONGATION OF CLOT FORMATION TIME, IUT OF PRBCS OF UP TO 52% OF THE ESTIMATED INTRAVASCULAR VOLUME DID NOT AFFECT FETAL COAGULATION FUNCTION BY TEG. OTHER THAN A SHORTER CLOT FORMATION TIME (R), THERE IS NO DIFFERENCE IN TEG VALUES BETWEEN ANEMIC PRETERM FETUSES AND HEALTHY TERM NEONATES AND HEALTHY ADULTS. BEYOND GENERALIZABLE KNOWLEDGE, THIS INFORMATION COULD BE EXPLOITED FOR FUTURE FETAL INTERVENTION TECHNIQUES.

Multimodal Patient Blood Management Program Based on a Three-pillar Strategy: A Systematic Review and Meta-analysis.

OBJECTIVES: To determine whether a multidisciplinary, multimodal Patient Blood Management (PBM) program for patients undergoing surgery is effective in reducing perioperative complication rate, and thereby is effective in improving clinical outcome. BACKGROUND: PBM is a medical concept with the focus on a comprehensive anemia management, to minimize iatrogenic (unnecessary) blood loss, and to harness and optimize patient-specific physiological tolerance of anemia. METHODS: A systematic review and meta-analysis was performed. Eligible studies had to address each of the 3 PBM pillars with at least 1 measure per pillar, for example, preoperative anemia management plus cell salvage plus rational transfusion strategy. The study protocol has been registered with PROSPERO (CRD42017079217). RESULTS: Seventeen studies comprising 235,779 surgical patients were included in this meta-analysis (100,886 pre-PBM group and 134,893 PBM group). Implementation of PBM significantly reduced transfusion rates by 39% [risk ratio (RR) 0.61, 95% confidence interval (CI) 0.55-0.68, P < 0.00001], 0.43 red blood cell units per patient (mean difference -0.43, 95% CI -0.54 to -0.31, P < 0.00001), hospital length of stay (mean difference -0.45, 95% CI -0.65 to -0.25, P < 0,00001), total number of complications (RR 0.80, 95% CI 0.74-0.88, P <0.00001), and mortality rate (RR 0.89, 95% CI 0.80-0.98, P = 0.02). CONCLUSIONS: Overall, a comprehensive PBM program addressing all 3 PBM pillars is associated with reduced transfusion need of red blood cell units, lower complication and mortality rate, and thereby improving clinical outcome. Thus, this first meta-analysis investigating a multimodal approach should motivate all executives and health care providers to support further PBM activities.

How do I perform cell salvage in obstetrics?

Maternal mortality in the United States is increasing. The leading cause of death is hemorrhage. Maternal hemorrhage can be profound, with entire blood volumes being lost. In most major blood loss surgery, autotranfusion (also known as cell salvage, cell saving, and intraoperative blood collection and readministration) is a technique that has been used to minimize allogeneic transfusion. Historically, autotransfusion has been considered contraindicated in the face of maternal hemorrhage because of a fear of incorporating amniotic fluid in the salvaged blood. Recent data suggests that this fear is unfounded, with several medical societies now recommending that autotransfusion be used during maternal hemorrhage. In this review, autotransfusion during maternal hemorrhage is discussed, and suggestions are made for how to make it most successful.

Patient Blood Management: Recommendations From the 2018 Frankfurt Consensus Conference.

IMPORTANCE: Blood transfusion is one of the most frequently used therapies worldwide and is associated with benefits, risks, and costs. OBJECTIVE: To develop a set of evidence-based recommendations for patient blood management (PBM) and for research. EVIDENCE REVIEW: The scientific committee developed 17 Population/Intervention/Comparison/Outcome (PICO) questions for red blood cell (RBC) transfusion in adult patients in 3 areas: preoperative anemia (3 questions), RBC transfusion thresholds (11 questions), and implementation of PBM programs (3 questions). These questions guided the literature search in 4 biomedical databases (MEDLINE, EMBASE, Cochrane Library, Transfusion Evidence Library), searched from inception to January 2018. Meta-analyses were conducted with the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) methodology and the Evidence-to-Decision framework by 3 panels including clinical and scientific experts, nurses, patient representatives, and methodologists, to develop clinical recommendations during a consensus conference in Frankfurt/Main, Germany, in April 2018. FINDINGS: From 17 607 literature citations associated with the 17 PICO questions, 145 studies, including 63 randomized clinical trials with 23 143 patients and 82 observational studies with more than 4 million patients, were analyzed. For preoperative anemia, 4 clinical and 3 research recommendations were developed, including the strong recommendation to detect and manage anemia sufficiently early before major elective surgery. For RBC transfusion thresholds, 4 clinical and 6 research recommendations were developed, including 2 strong clinical recommendations for critically ill but clinically stable intensive care patients with or without septic shock (recommended threshold for RBC transfusion, hemoglobin concentration <7 g/dL) as well as for patients undergoing cardiac surgery (recommended threshold for RBC transfusion, hemoglobin concentration <7.5 g/dL). For implementation of PBM programs, 2 clinical and 3 research recommendations were developed, including recommendations to implement comprehensive PBM programs and to use electronic decision support systems (both conditional recommendations) to improve appropriate RBC utilization. CONCLUSIONS AND RELEVANCE: The 2018 PBM International Consensus Conference defined the current status of the PBM evidence base for practice and research purposes and established 10 clinical recommendations and 12 research recommendations for preoperative anemia, RBC transfusion thresholds for adults, and implementation of PBM programs. The relative paucity of strong evidence to answer many of the PICO questions supports the need for additional research and an international consensus for accepted definitions and hemoglobin thresholds, as well as clinically meaningful end points for multicenter trials.

Antenatal anemia increases the risk of receiving postpartum red blood cell transfusions although the overall risk of transfusion is low.

BACKGROUND: The objective was to determine if antenatal anemia is associated with postpartum red blood cell (RBC) transfusion. STUDY DESIGN AND METHODS: Women who gave birth at a regional, tertiary care maternity hospital between December 1, 2015, and September 31, 2016, with a documented antenatal hemoglobin (Hb) concentration were included. Women were grouped into those who were either anemic (Hb < 11.0 g/dL) or nonanemic. The change in Hb concentration and RBC transfusion rates were compared between the anemic and nonanemic women, as well as by the mode of delivery (vaginal vs. Cesarean). To estimate the volume of blood loss in a normal delivery, the mean postpartum Hb concentration decrease for the not transfused women was calculated by subtracting the nadir postpartum Hb concentration from the antenatal Hb concentration and averaging these concentrations according to delivery route. RESULTS: Of 8039 cases analyzed, 1562 (19%) had antenatal anemia and 6477 (81%) were nonanemic. Of the anemic women, 57 (3.6%) received an RBC transfusion compared to 49 (0.76%) of the nonanemic women (p = 0.0001; odds ratio, 4.97; 95% confidence interval, 3.38-7.31). Antenatal anemia was significantly associated with receiving an RBC transfusion regardless of mode of delivery for those who delivered vaginally (p = 0.0001) or by Cesarean (p = 0.0001) compared to those who were nonanemic. The mean postpartum Hb concentration decrease was 1.12 ± 1.12 g/dL for vaginal deliveries and 1.34 ± 0.21 g/dL for Cesarean deliveries in the not transfused women (p = 0.0001). CONCLUSION: Although the overall rate of transfusion was low, antenatal anemia was significantly associated with receiving a postpartum RBC transfusion.

Blood product transfusion and wastage rates in obstetric hemorrhage.

BACKGROUND: Bleeding emergencies can complicate pregnancies. Understanding the disposition of the products that are issued in this clinical setting can help inform inventory levels at hospitals where obstetric patients are seen. STUDY DESIGN AND METHODS: Patients who had an obstetric hemorrhage of any etiology between January 2013 and June 2017, and whose resuscitation began with uncrossmatched red blood cells (RBCs) or emergency-issued plasma or platelets (PLT), were included. The disposition of all blood products issued within 6 hours of the first uncrossmatched or emergency-issued product was documented, as was basic patient demographic information. RESULTS: In total, 301 women with an obstetric hemorrhage from seven academic institutions were identified. Their mean ± standard deviation age was 30.9 ± 6.1 years, 45.2% delivered by Cesarean section, and 40.5% delivered vaginally, while 12% did not deliver. The largest single etiology of hemorrhage was related to abnormal placentation. Of the 2280 issued RBC units, 55% were transfused, 43% were returned, and 2% were wasted. The rates of transfusion of the other blood products ranged from 58% for plasma units to 82% for cryoprecipitate. Seventeen percent of the issued cryoprecipitate units were wasted, the highest of any blood product. The rate of a patient receiving a transfusion when at least one blood product had been ordered ranged from 74% for PLTs to 91% for cryoprecipitate. CONCLUSION: Although the rates of receiving a transfusion of at least one blood product when one is ordered was high, many of the issued units were returned, especially for RBCs.

Cost-effectiveness Analysis of Intraoperative Cell Salvage for Obstetric Hemorrhage.

BACKGROUND: Cost-effectiveness analyses on cell salvage for cesarean delivery to inform national and societal guidelines on obstetric blood management are lacking. This study examined the cost-effectiveness of cell salvage strategies in obstetric hemorrhage from a societal perspective. METHODS: Markov decision analysis modeling compared the cost-effectiveness of three strategies: use of cell salvage for every cesarean delivery, cell salvage use for high-risk cases, and no cell salvage. A societal perspective and lifetime horizon was assumed for the base case of a 26-yr-old primiparous woman presenting for cesarean delivery. Each strategy integrated probabilities of hemorrhage, hysterectomy, transfusion reactions, emergency procedures, and cell salvage utilization; utilities for quality of life; and costs at the societal level. One-way and Monte Carlo probabilistic sensitivity analyses were performed. A threshold of $100,000 per quality-adjusted life-year gained was used as a cost-effectiveness criterion. RESULTS: Cell salvage use for cases at high risk for hemorrhage was cost-effective (incremental cost-effectiveness ratio, $34,881 per quality-adjusted life-year gained). Routine cell salvage use for all cesarean deliveries was not cost-effective, costing $415,488 per quality-adjusted life-year gained. Results were not sensitive to individual variation of other model parameters. The probabilistic sensitivity analysis showed that at the $100,000 per quality-adjusted life-year gained threshold, there is more than 85% likelihood that cell salvage use for cases at high risk for hemorrhage is favorable. CONCLUSIONS: The use of cell salvage for cases at high risk for obstetric hemorrhage is economically reasonable; routine cell salvage use for all cesarean deliveries is not. These findings can inform the development of public policies such as guidelines on management of obstetric hemorrhage.

A Review of the Impact of Obstetric Anesthesia on Maternal and Neonatal Outcomes.

Obstetric anesthesia has evolved over the course of its history to encompass comprehensive aspects of maternal care, ranging from cesarean delivery anesthesia and labor analgesia to maternal resuscitation and patient safety. Anesthesiologists are concerned with maternal and neonatal outcomes, and with preventing and managing complications that may present during childbirth. The current review will focus on recent advances in obstetric anesthesia, including labor anesthesia and analgesia, cesarean delivery anesthesia and analgesia, the effects of maternal anesthesia on breastfeeding and fever, and maternal safety. The impact of these advances on maternal and neonatal outcomes is discussed. Past and future progress in this field will continue to have significant implications on the health of women and children.

In Vitro Evaluation of a Novel Image Processing Device to Estimate Surgical Blood Loss in Suction Canisters.

BACKGROUND: Clinicians are tasked with monitoring surgical blood loss. Unfortunately, there is no reliable method available to assure an accurate result. Most blood lost during surgery ends up on surgical sponges and within suction canisters. A novel Food and Drug Administration-cleared device (Triton system; Gauss Surgical, Inc, Los Altos, CA) to measure the amount of blood present on sponges using computer image analysis has been previously described. This study reports on performance of a complementary Food and Drug Administration-cleared device (Triton Canister System; Gauss Surgical, Inc, Los Altos, CA) that uses similar image analysis to measure the amount of blood in suction canisters. METHODS: Known quantities of expired donated whole blood, packed red blood cells, and plasma, in conjunction with various amounts of normal saline, were used to create 207 samples representing a wide range of blood dilutions commonly seen in suction canisters. Each sample was measured by the Triton device under 3 operating room lighting conditions (bright, medium, and dark) meant to represent a reasonable range, resulting in a total of 621 measurements. Using the Bland-Altman method, the measured hemoglobin (Hb) mass in each sample was compared to the results obtained using a standard laboratory assay as a reference value. The analysis was performed separately for samples measured under each lighting condition. It was expected that under each separate lighting condition, the device would measure the various samples within a prespecified clinically significant Hb mass range (±30 g per canister). RESULTS: The limits of agreement (LOA) between the device and the reference method for dark (bias: 4.7 g [95% confidence interval {CI}, 3.8-5.6 g]; LOA: -8.1 g [95% CI, -9.7 to -6.6 g] to 17.6 g [95% CI, 16.0-19.1 g]), medium (bias: 3.4 g [95% CI, 2.6-4.1 g]; LOA: -7.4 g [95% CI, -8.7 to -6.1 g] to 14.2 g [95% CI, 12.9-15.5 g]), and bright lighting conditions (bias: 4.1 g [95% CI, 3.2-4.9 g]; LOA: -7.6 g [95% CI, -9.0 to -6.2 g] to 15.7 g [95% CI, 14.3-17.1 g]) fell well within the predetermined clinically significant limits of ±30 g. Repeated measurements of the samples under the various lighting conditions were highly correlated with intraclass correlation coefficient of 0.995 (95% CI, 0.993-0.996; P < .001), showing that lighting conditions did not have a significant impact on measurements. Hb mass bias was significantly associated with hemolysis level (Spearman ρ correlation coefficient, -0.137; P = .001) and total canister volume (Spearman ρ correlation coefficient, 0.135; P = .001), but not ambient illuminance. CONCLUSIONS: The Triton Canister System was able to measure the Hb mass reliably with clinically acceptable accuracy in reconstituted blood samples representing a wide range of Hb concentrations, dilutions, hemolysis, and ambient lighting settings.

Real-time evaluation of an image analysis system for monitoring surgical hemoglobin loss.

Monitoring blood loss is important for management of surgical patients. This study reviews a device (Triton) that uses computer analysis of a photograph to estimate hemoglobin (Hb) mass present on surgical sponges. The device essentially does what a clinician does when trying to make a visual estimation of blood loss by looking at a sponge, albeit with less subjective variation. The performance of the Triton system is reported upon in during real-time use in surgical procedures. The cumulative Hb losses estimated using the Triton system for 50 enrolled patients were compared with reference Hb measurements during the first quarter, half, three-quarters and full duration of the surgery. Additionally, the estimated blood loss (EBL) was calculated using the Triton measured Hb loss and compared with values obtained from both visual estimation and gravimetric measurements. Hb loss measured by Triton correlated with the reference method across the four measurement intervals. Bias remained low and increased from 0.1 g in the first quarter to 3.7 g at case completion. The limits of agreement remained narrow and increased proportionally from the beginning to the end of the cases, reaching a maximum range of -15.3 to 22.7 g. The median (IQR) difference of EBL derived from the Triton system, gravimetric method and visual estimation versus the reference value were 13 (74), 389 (287), and 4 (230) mL, respectively. Use of the Triton system to measure Hb loss in real-time during surgery is feasible and accurate.

Transfusion reactions: prevention, diagnosis, and treatment.

Blood transfusion is one of the most common procedures in patients in hospital so it is imperative that clinicians are knowledgeable about appropriate blood product administration, as well as the signs, symptoms, and management of transfusion reactions. In this Review, we, an international panel, provide a synopsis of the pathophysiology, treatment, and management of each diagnostic category of transfusion reaction using evidence-based recommendations whenever available.