Limitations of Gravimetric Quantitative Blood Loss during Cesarean Delivery.

Objective This study examined the accuracy, sources of error, and limitations of gravimetric quantification of blood loss (QBL) during cesarean delivery. Study Design Blood loss determined by assays of the hemoglobin content on surgical sponges and in suction canisters was compared with QBL in 50 parturients. Results QBL was moderately correlated to the actual blood loss ( r = 0.564; p < 0.001). Compared with the reference assay, QBL overestimated blood loss for 44 patients (88%). QBL deviated from the assayed blood loss by more than 250 mL in 34 patients (68%) and by more than 500 mL in 16 cases (32%). Assayed blood loss was more than 1,000 mL in four patients. For three of these patients, QBL was more than 1,000 mL (sensitivity = 75%). QBL was more than 1,000 mL in 12 patients. While three of these had an assayed blood loss of more than 1,000 mL, 9 of the 46 patients with blood losses of less than 1,000 mL by the assay (20%) were incorrectly identified as having postpartum hemorrhage by QBL (false positives). The specificity of quantitative QBL for detection of blood loss more than or equal to 1,000 mL was 80.4%. Conclusion QBL was only moderately correlated with the reference assay. While overestimation was more common than underestimation, both occurred. Moreover, QBL was particularly inaccurate when substantial bleeding occurred. Key Points QBL is inaccurate in cesarean delivery.QBL deviated from the assay result by more than 500 mL in 32% of cases.QBL sensitivity and specificity for hemorrhage is 75.0% (95% confidence interval [CI]: 0.19-0.93) and 80.4% (95% CI: 0.69-0.92), respectively.

Automated Quantification of Blood Loss versus Visual Estimation in 274 Vaginal Deliveries.

OBJECTIVE: The aim of the study is to compare quantified blood loss measurement (QBL) using an automated system (Triton QBL, Menlo Park, CA) with visual blood loss estimation (EBL) during vaginal delivery. STUDY DESIGN: During 274 vaginal deliveries, both QBL and EBL were determined. The automated system batch weighs blood containing sponges, towels, pads, and other supplies and automatically subtracts their dry weights and also the measured amount of amniotic fluid. Each method was performed independently, and clinicians were blinded to the device's results. RESULTS: Median QBL (339 mL [217-515]) was significantly greater than median EBL (300 mL [200-350]; p < 0.0001). The Pearson's correlation between EBL and QBL was poor (r = 0.520) and the Bland-Altman's limits of agreement were wide (>900 mL). QBL measured blood loss >500 mL occurred in 73 (26.6%) patients compared with 14 (5.1%) patients using visual estimation (p < 0.0001). QBL ≥ 1,000 mL was recorded in 11 patients (4.0%), whereas only one patient had an EBL blood loss of 1,000 mL and none had EBL >1,000 mL (p = 0.002). CONCLUSION: Automated QBL recognizes more patients with excessive blood loss than visual estimation. To realize the value of QBL, clinicians must accept the inadequacy of visual estimation and implement protocols based on QBL values. Further studies of clinical outcomes related to QBL are needed. KEY POINTS: · QBL detects hemorrhage more frequently than visual estimation.. · Median QBL is significantly greater than median EBL.. · There is poor agreement between QBL and EBL..

Reducing red blood cell transfusion in orthopedic and cardiac surgeries with Antifibrinolytics: A laboratory medicine best practice systematic review and meta-analysis.

OBJECTIVES: To evaluate the effectiveness of antifibrinolytics tranexamic acid (TA), ε-aminocaproic acid (EACA), and aprotinin to decrease overuse of red blood cell transfusions in adult surgical and non-surgical patients. METHODS: This review followed the Centers for Disease Control and Prevention (CDC) Laboratory Medicine Best Practice (LMBP™) Systematic Review (A-6) method. Eligible studies were assessed for evidence of effectiveness of TA or EACA in reducing the number of patients transfused or the number of whole blood transfusions. RESULTS: Seventy-two articles met LMBP™ inclusion criteria. Fifty-six studies assessed Topical, Intra-articular Injection, or Intravenous TA, 4 studied EACA, and 12 studied the effectiveness of aprotinin. The overall strength of the body of evidence of effectiveness for each of these practices was rated as high. CONCLUSION: LMBP™ recommends the use of topical, intra-articular injection, or intravenous tranexamic acid and the use of ε-aminocaproic acid for reducing overuse of red blood cell transfusion.

Restrictive Transfusion Strategy and Clinical Decision Support Practices for Reducing RBC Transfusion Overuse.

OBJECTIVES: Assess support for the effectiveness of two separate practices, restrictive transfusion strategy and computerized physician order entry/clinical decision support (CPOE/CDS) tools, in decreasing RBC transfusions in adult surgical and nonsurgical patients. METHODS: Following the Centers for Disease Control and Prevention Laboratory Medicine Best Practice (LMBP) Systematic Review (A-6) method, studies were assessed for quality and evidence of effectiveness in reducing the percentage of patients transfused and/or units of blood transfused. RESULTS: Twenty-five studies on restrictive transfusion practice and seven studies on CPOE/CDS practice met LMBP inclusion criteria. The overall strength of the body of evidence of effectiveness for restrictive transfusion strategy and CPOE/CDS was rated as high. CONCLUSIONS: Based on these procedures, adherence to an institutional restrictive transfusion strategy and use of CPOE/CDS tools for hemoglobin alerts or reminders of the institution's restrictive transfusion policies are effective in reducing RBC transfusion overuse.

Accurate Assessment of Blood Loss during Cesarean Delivery Improves Estimation of Postoperative Hemoglobin.

OBJECTIVE: To determine if accurate blood loss determination during cesarean delivery can improve the prediction of postoperative hemoglobin levels. STUDY DESIGN: This is a retrospective cohort study using visually estimated blood loss (traditional, n = 2,025) versus estimates using a mobile application that photographs sponges and canisters and calculates their hemoglobin content (device, n = 756). RESULTS: The correlation between the actual and predicted postoperative day 1 hemoglobin value (PPO1 Hgb) was better in the device group (R 2 = 0.519, correlation = 0.720) than in the traditional group (R 2 = 0.429, correlation = 0.655) (p = 0.005). For patients in the device group where the estimated blood loss was >1,000 mL (n = 53), the PPO1 Hgb was also better correlated with the actual value (R 2 = 0.319, correlation = 0.565) than the predictions using visually estimated blood loss for those patients in the device group whose visual estimation was >1,000 mL (n = 32) (R 2 = 0.035, correlation = 0.187) (p = 0.027). CONCLUSION: Implementation of a device that accurately measures blood loss allows for a better prediction of postoperative day 1 hemoglobin concentration than is possible using visual blood loss estimation. This improvement was seen in the entire patient group and was particularly prominent in patients with blood losses of > 1,000 mL.

Anemia Management and Audit Feedback Practices for Reducing Overuse of RBC Transfusion: A Laboratory Medicine Best Practice Systematic Review and Meta-Analysis.

Objectives: To evaluate the effectiveness of anemia management and audit with feedback practices in reducing overuse of RBC transfusion. Methods: This review follows the Centers for Disease Control and Prevention's Laboratory Medicine Best Practice Systematic Review (A-6) method. We searched the literature and solicited unpublished studies on practices to reduce overuse of RBC transfusions as measured by reductions in units transfused and proportion of patients transfused. Results: Thirteen studies on preoperative anemia management and three studies on audit feedback practices met inclusion criteria. Strength of evidence was high to moderate for reducing the number of units and proportion of patients transfused. Conclusions: Preoperative anemia management reduces the proportion of patients transfused and units of RBCs transfused. Audit with feedback across cases, physicians, and/or service areas, as part of a continuous quality improvement practice, reduces the proportion of patients and units of RBCs transfused.

How does blood loss relate to the extent of surgical wound excision?

PURPOSE: We investigated a novel system that uses image-processing algorithms to accurately measure the hemoglobin content of discarded surgical sponges to determine how blood loss relates to the excised area when current methods to minimize bleeding are employed. The system was used during 130 procedures in adult patients having wound excisions ≥1% BSA (study group). An historic group of 105 similar cases in whom visually estimated blood was determined was also evaluated. RESULTS: Surgical blood loss was less than previous estimates. The correlation between blood loss and the excised area in the study group was poor (R2=0.3988 for all patients and R2=0.1439 for excisions ≥10% BSA). Moreover, the visual estimates of blood loss in the historic group were more closely related to excised area than the accurate measurements in the study group (R2=0.6017 (historic), R2=0.3988 (study), p<0.001 for both). The mean absolute unstandardized residuals were 140.18±158.52 (historic) vs. 307.99±317.03 (study), p<0.001. CONCLUSIONS: As demonstrated in the historic group, visual estimates of blood loss tend to be more related to the size of excision than the amount of bleeding. The actual blood loss is not well correlated with the extent of excision. Clinicians should not rely on traditional blood loss estimates. Accurate measurement is needed to inform transfusion decisions and guide care.

Clinical Experience with the Implementation of Accurate Measurement of Blood Loss during Cesarean Delivery: Influences on Hemorrhage Recognition and Allogeneic Transfusion.

OBJECTIVE: This article compares hemorrhage recognition and transfusion using accurate, contemporaneous blood loss measurement versus visual estimation during cesarean deliveries. STUDY DESIGN: A retrospective cohort study using visually estimated blood loss (traditional, n = 2,025) versus estimates using a mobile application that photographs sponges and canisters and calculates their hemoglobin content (device, n = 756). RESULTS: Blood loss > 1,000 mL was recognized in 1.9% of traditional visual estimation patients, while measured blood loss of > 1,000 mL occurred in 8.2% of device patients (p < 0.0001). In both groups, this was accompanied by a greater decrease in transfusion-adjusted hemoglobin levels than occurred in patients without hemorrhage (p < 0.0001). Despite similar transfusion rates (1.6% in both groups), fewer red cell units were given to transfused patients in the device group (1.83 ± 0.58 versus 2.56 ± 1.68 units; p = 0.038). None of the patients in the device group received plasma or cryoprecipitate. Seven patients in the traditional group received these products (p = 0.088). Device use was associated with shorter hospital stays (4.0 ± 2.3 versus 4.4 ± 2.9 days; p = 0.0006). CONCLUSION: The device identified hemorrhages more frequently than visual estimation. Device-detected hemorrhages appeared clinically relevant. Blood product transfusion was reduced possibly due to earlier recognition and treatment, although further studies are needed to verify the conclusion.

Accuracy of Blood Loss Measurement during Cesarean Delivery.

Objective This study aims to compare the accuracy of visual, quantitative gravimetric, and colorimetric methods used to determine blood loss during cesarean delivery procedures employing a hemoglobin extraction assay as the reference standard. Study Design In 50 patients having cesarean deliveries blood loss determined by assays of hemoglobin content on surgical sponges and in suction canisters was compared with obstetricians' visual estimates, a quantitative gravimetric method, and the blood loss determined by a novel colorimetric system. Agreement between the reference assay and other measures was evaluated by the Bland-Altman method. Results Compared with the blood loss measured by the reference assay (470 ± 296 mL), the colorimetric system (572 ± 334 mL) was more accurate than either visual estimation (928 ± 261 mL) or gravimetric measurement (822 ± 489 mL). The correlation between the assay method and the colorimetric system was more predictive (standardized coefficient = 0.951, adjusted R2 = 0.902) than either visual estimation (standardized coefficient = 0.700, adjusted R2 = 00.479) or the gravimetric determination (standardized coefficient = 0.564, adjusted R2 = 0.304). Conclusion During cesarean delivery, measuring blood loss using colorimetric image analysis is superior to visual estimation and a gravimetric method. Implementation of colorimetric analysis may enhance the ability of management protocols to improve clinical outcomes.

Use of Thromboelastography (TEG) for Detection of New Oral Anticoagulants.

CONTEXT: The clinical introduction of new oral anticoagulants (NOACs) has stimulated the development of tests to quantify the effects of these drugs and manage complications associated with their use. Until recently, the only treatment choices for the prevention of venous thromboembolism in orthopedic surgical patients, as well as for stroke and systemic embolism in patients with atrial fibrillation, were vitamin K antagonists, antiplatelet drugs, and unfractionated and low-molecular-weight heparins. With the approval of NOACs, treatment options and consequent diagnostic challenges have expanded. OBJECTIVE: To study the utility of thromboelastography (TEG) in monitoring and differentiating between 2 currently approved classes of NOACs, direct thrombin inhibitors (dabigatran) and factor Xa inhibitors (rivaroxaban and apixaban). DESIGN: Blood samples from healthy volunteers were spiked with each NOAC in both the presence and absence of ecarin, and the effects on TEG were evaluated. RESULTS: Both the kaolin test reaction time (R time) and the time to maximum rate of thrombus generation were prolonged versus control samples and demonstrated a dose response for apixaban (R time within the normal range) and dabigatran. The RapidTEG activated clotting time test allowed the creation of a dose-response curve for all 3 NOACs. In the presence of anti-Xa inhibitors, the ecarin test promoted significant shortening of kaolin R times to the hypercoagulable range, while in the presence of the direct thrombin inhibitor only small and dose-proportional R time shortening was observed. CONCLUSIONS: The RapidTEG activated clotting time test and the kaolin test appear to be capable of detecting and monitoring NOACs. The ecarin test may be used to differentiate between Xa inhibitors and direct thrombin inhibitors. Therefore, TEG may be a valuable tool to investigate hemostasis and the effectiveness of reversal strategies for patients receiving NOACs.

Implementation of a comprehensive blood conservation program can reduce blood use in a community cardiac surgery program.

OBJECTIVE: The study objective was to determine the effects of implementing a blood conservation algorithm on blood product use and outcomes in a community cardiac surgery program. METHODS: A blood management strategy including lower hemoglobin transfusion threshold and algorithm-driven decisions was adopted. Intraoperatively, point-of-care testing was used to avoid inappropriate component transfusion. A low prime perfusion circuit was adopted. Blood was withdrawn from patients before initiating bypass when possible. Patients undergoing coronary and valve procedures were included. Outlier patients receiving more than 10 units packed red blood cells were excluded. Data were collected for 6 months as a baseline group (group I). A 3-month period of program implementation was allotted. Data were subsequently collected for 6 months and comprised the study patients (group II). Prospective data were collected on demographics, blood use, and outcomes. RESULTS: Group I comprised 481 patients, and group II comprised 551 patients. Group II received fewer units of packed red blood cells, fresh-frozen plasma, and cryoprecipitate than group I. There was no difference in platelets transfused. Total blood product use was reduced by 40% in group II (P < .001). The overall 30-day mortality was 1.3%. There were no differences in mortality, reoperation for bleeding, or other postoperative outcomes between the groups. CONCLUSIONS: Implementation of a comprehensive blood conservation algorithm can be rapidly introduced, leading to reductions in blood and component use with no detrimental effect on early outcomes. Point-of-care testing can direct component transfusion in coagulopathic cases, with most coagulopathic patients requiring platelets. Further research will determine the effects of reduced transfusions on long-term outcomes.

Phase II trial of sequential chemotherapy followed by chemoradiation, surgery, and postoperative chemotherapy for the treatment of stage IIIA/IIIB non-small-cell lung cancer.

BACKGROUND: The optimal treatment of locally advanced non-small-cell lung cancer remains a challenge. Although the benefit of combined chemoradiation has been established, the optimal chemotherapy regimen, timing of full-dose chemotherapy, and how best to combine chemotherapy with radiation to maximize systemic and radiosensitizing effects remain unclear. PATIENTS AND METHODS: Twenty-nine patients with pathologically confirmed stage IIIA/IIIB non-small-cell lung cancer were included in a phase II trial of sequential carboplatin/paclitaxel followed by chemoradiation, surgery, and postoperative gemcitabine. Twenty-five patients (86%) completed the concurrent chemotherapy and radiation therapy phase and were eligible for surgery. At restaging, 7 patients (21%) showed disease progression. Seventeen patients (59%) went on to surgery. Few were able to tolerate full postoperative chemotherapy. RESULTS: The 1-year overall survival rate was 61%, with a 2-year survival rate of 56%. Median overall survival was 25.2 months. Seven of the patients are alive and without recurrence at the time of this writing. Our median follow-up time was 22.2 months. Reversible grade 3/4 toxicities were fairly common, experienced in 45% of patients. CONCLUSION: Our results with this combined modality approach are comparable with those of previous, similar studies. Postoperative chemotherapy after initial combined modality therapy is often not feasible, reinforcing the value of initial systemic therapy. Long-term results are still suboptimal and await studies adding targeted therapies to our usual chemotherapy/radiation approaches.

The thymus: a comprehensive review.

Since first being described as such by Galen of Pergamum (130-200 ad), the thymus has remained an "organ of mystery" throughout the 2000-year history of medicine. The thymus reaches its maximum weight in puberty and subsequently undergoes involution, and thus is hardly an eye-catching structure on imaging studies performed in healthy adults. However, once there has been involvement of the thymus by a disease process, the gland demonstrates a variety of clinical and radiologic manifestations that require comprehensive understanding of each entity. Furthermore, it is important for radiologists to be familiar with the current World Health Organization histologic classification scheme for thymic epithelial tumors and to understand its clinical-pathologic, radiologic, and prognostic features.

Microdebrider bronchoscopy: a new tool for the interventional bronchoscopist.

PURPOSE: We report our experience with a new airway tool, the microdebrider, in treating central airway obstruction. DESCRIPTION: From April 2002 to April 2004, 23 patients undergoing treatment of central airway obstruction were managed with the microdebrider. All procedures were done under general anesthesia with either a rigid bronchoscope (19 patients) or a suspension laryngoscope (4 patients). The microdebrider was used in an oscillating mode with rotation speeds of 1,000 to 3,000 rpm to resect obstructing tissue. EVALUATION: Fourteen patients (61%) had tracheal granulation tissue from prior intubation or tracheostomy, 6 (26%) had idiopathic subglottic stenosis, and 3 (26%) had malignant disease. Obstructing lesions were rapidly removed in all patients with interventions lasting between 2 and 15 minutes. There were no procedure-related complications. No patients required reoperation for airway obstruction in follow-up ranging from 1 to 24 months. CONCLUSIONS: Microdebrider bronchoscopy is a new technique that allows for precise, rapid, and safe removal of lesions obstructing the central airways. Complications of thermal modalities such as airway injury, tracheoesophageal fistulas, and airway fires can be avoided.

The role of surgery in N2 non-small cell lung cancer.

Historical series document the poor survival (7-16% at 5 years) for patients with N2-positive, stage IIIA non-small cell lung cancer (NSCLC) treated with primary surgery. In 1994, two small randomized trials showed the superiority of induction chemotherapy followed by surgery over surgery alone for stage IIIA NSCLC. These findings, as well as subsequent studies showing the superiority of chemoradiotherapy over chemotherapy alone in nonoperable stage III disease, prompted investigations of preoperative chemoradiotherapy for N2-positive patients. As induction therapy improved, the use of resection in stage IIIA NSCLC was called into question. An Intergroup trial addressing this issue randomized 392 patients to induction chemoradiotherapy followed by surgery versus definitive chemoradiotherapy. Surgery following induction chemoradiotherapy was associated with a significant improvement in progression-free survival and almost a 50% reduction in local failure. As distant relapse is common, survival is likely to be enhanced only in those patients who respond to the systemic arm of treatment. Identification of genetic or biochemical markers of response, minimally invasive techniques to pathologically restage, or improved statistical or chemosensitivity analyses are needed to enhance our ability to select patients who will benefit from resection.

Endoscopic removal of metallic airway stents.

BACKGROUND: Complications of metallic airway stents include granulation tissue formation, fracture of struts, migration, and mucous plugging. When these complications result in airway injury or obstruction, it may become necessary to remove the stent. There have been few reports detailing techniques and complications associated with endoscopic removal of metallic airway stents. We report our experience with endoscopic removal of 30 such stents over a 3-year period. METHODS: We conducted a retrospective review of 25 patients who underwent endoscopic stent removal from March 2001 to April 2004. The patients ranged in age from 17 to 80 years (mean, 56.3 years). There were 10 male and 15 female patients. The stents had been placed for nonmalignant disease in 20 patients (80%) and malignant disease in 5 patients (20%). All procedures were done under general anesthesia with a rigid bronchoscope. Special attention was focused on the technique of stent removal and postoperative complications. RESULTS: Thirty metallic airway stents were successfully removed from 25 consecutive patients over a 3-year period. The basic method of removal involved the steady application of traction to the stent with alligator forceps. In all cases, an instrument such as the barrel of the rigid bronchoscope or a Jackson dilator was employed to help separate the stent from the airway wall before removal was attempted. In some instances, the airway wall was pretreated with thermal energy prior to stent removal. Complications were as follows: retained stent pieces (n = 7), mucosal tear with bleeding (n = 4), re-obstruction requiring temporary silicone stent placement (n = 14), need for postoperative mechanical ventilation (n = 6), and tension pneumothorax (n = 1). CONCLUSIONS: Although metallic stents may be safely removed endoscopically, complications are common and must be anticipated. Other investigators have described airway obstruction and death as a result of attempted stent removal. Placement and removal of metallic airway stents should only be performed at centers that are prepared to deal with the potentially life-threatening complications.

Prevalence and outcomes of anemia in surgery: a systematic review of the literature.

Untreated preoperative anemia and acute perioperative blood loss may add to surgical risk. To understand the prevalence of anemia in surgical patients (with a primary focus on preoperative anemia), and the impact that preexisting anemia has on transfusion rates as well as on clinical and functional outcomes, a systematic review was performed of articles published between January 1966 and February 2003. The estimates of anemia prevalence in the literature ranged widely, from 5% in geriatric women with hip fracture to 75.8% in patients with Dukes stage D colon cancer. Diagnosis of anemia was most strongly associated with an increased risk of receiving an allogeneic transfusion. In general, patients who donated autologous blood preoperatively received less allogeneic blood than those who did not donate. There was some suggestion that lower hemoglobin levels are associated with decreased survival rates, although this was not found universally. Too few studies were found that evaluated the impact of anemia on other outcomes, such as functional status and costs and resource utilization, to draw reliable conclusions. Several other factors also limited the interpretation of the data, including the lack of a uniform definition for anemia and a dearth of studies expressly designed to quantify the prevalence and impact of anemia. Establishing a uniform definition and specifically evaluating the effect of anemia on outcomes are important considerations for future study.

Mediastinal and chest wall limitations to asymmetry of lung inflation.

The extent to which inflation of one lung increases pleural pressure around the contralateral lung could affect ventilatory function, e.g., after pneumonectomy or lung transplantation. The rise in contralateral pleural pressure is limited by mediastinal stiffness and other chest wall properties. To estimate these properties, we determined an elastance of asymmetric expansion (E(Asym)) in 20 supine adults undergoing thoracic surgery requiring endobronchial intubation. Esophageal pressure, measured with a balloon catheter, was used as an estimate of pleural pressure for determining chest wall elastance during symmetric inflation. Pressures measured in the left and right lung airways during sequential asymmetric inflations with known volumes were used to calculate E(Asym) and elastances of left and right lungs by using a four-element mathematical model. Elastances (means +/- SD) were 13.0 +/- 8.7 (E(Asym)), 14.0 +/- 7.0 (left lung), 12.2 +/- 6.1 (right lung), and 6.7 +/- 2.1 cmH(2)O/l (chest wall). E(Asym) was high in three patients with prior cardiac surgery or mediastinal radiation therapy, suggesting that mediastinal stiffening due to scarring and fibrosis reduced pressure transmission between hemithoraxes. Simulations with a previously published model showed that changes in E(Asym) in the range of values observed could substantially affect lung ventilation after single-lung transplantation for emphysema.