A model for clinical estimation of perioperative hemorrhage

Study to estimate the average blood loss in different orthopedic procedures: A retrospective review

Background

In orthopedic surgery, bleeding is an inevitable side effect. The study's aim was to provide estimated blood loss values in various orthopedic procedures and take a step towards developing statistically reliable formulae. This can provide blood loss values in orthopedic surgery, which will be a very good tool for operative planning.

Materials and methods

We reviewed case notes of 282 patients in a UK based trauma center from December 2020 to March 2021,who had undergone a various orthopedic procedures. The results were analyzed using SPSS version 25.

Results

Most common fracture was neck of femur (37.5%)followed by intertrochanteric fractures(27.6%). Paired t-test was used, and there is good evidence (t281 = 14.957, p = 0.000) that intraoperative transfusions increased HB levels in patients (t281 = 14.957, p = 0.000) by an average of 1.331 points, with a 95% confidence interval of 1.156–1.506. As a result, the variation between the Pre-op and Post-op HB levels is statistically important but minimal. We can see that the mean blood loss is statistically different in different age groups (0.03) of patients and by the existence of co-morbids using analysis of variance (0.04). The average number of days spent in the hospital varies by surgical type (0.01) performed on patients.

Conclusion

Orthopedic surgery can be associated with high levels of blood loss. There is a significant relation between fracture form and age groups, change of wound dressing (COD), use of a tourniquet, and drain insertion, no connection was noted between gender and fracture types.

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Bleeding is an unavoidable side effect of most surgical operations, including orthopaedic surgery.

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There is a scarcity of literature that can provide us an estimate of how much blood will be lost during various orthopaedic operations.

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Goal of the study was to offer estimated blood loss estimates in various orthopaedic operations.

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There is a significant relationship between fracture type and age groups, change of wound dressing (COD), use of a tourniquet.

Perioperative haematological outcomes following total knee arthroplasty in haemophiliacs

PURPOSE

Patients with haemophilia suffer from recurrent joint haemarthrosis. This can progress to symptomatic arthropathy commonly affecting the knee. While modern coagulation strategies have reduced those proceeding to end-stage arthropathy, total knee arthroplasty (TKA) remains the optimal treatment for some patients. Despite innovation in perioperative haematological management, concerns about the potential for excessive haemorrhage still exist. The aim of this study is to quantify immediate postoperative blood loss and haematological complications in haemophiliacs following TKA.

METHODS

A retrospective study of patients with haemophilia types A or B who underwent a TKA over a 12-year period at a single institution was conducted. These patients were compared to both a non-haemophiliac control group and to published standards in non-haemophiliacs undergoing TKA.

RESULTS

Twenty-one TKA procedures in 18 patients (72% haemophilia A, 28% haemophilia B) were suitable for inclusion with a mean age of 44 years. The mean haemoglobin drops at 24 and 48 h postoperatively were 2.7 g/dl and 3.8 g/dl respectively. There was no significant difference in haemoglobin drop at 48 h postoperatively when compared to the non-haemophiliac control group (P = 0.2644). There were no immediate perioperative complications and two patients (9.6%) required postoperative transfusion.

CONCLUSION

Haemophiliacs undergoing a unilateral primary TKA in a specialised tertiary referral centre appear to have comparable rates of perioperative blood loss when compared to both a non-haemophiliac control group as and published haemostatic standards in non-haemophiliac patients following TKA. Perioperative management with expert orthopaedic and haematological input is recommended to optimise outcomes in this complex patient group.

Comparison of common perioperative blood loss estimation techniques: a systematic review and meta-analysis

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.

The Effect of Preoperative Administration of Intravenous Tranexamic Acid During Revision Hip Arthroplasty: A Retrospective Study

BACKGROUND

Revision hip arthroplasty poses several challenges, including the management of perioperative blood loss. Recent studies have validated the use of tranexamic acid in primary total hip arthroplasty, showing reduced blood loss and decreased number of allogenic blood transfusions. The effectiveness of tranexamic acid has not been well studied in the revision hip arthroplasty setting.

METHODS

We performed a retrospective review of 1,072 patients who underwent revision hip arthroplasty at our institution from 2008 to 2016. A total of 634 patients met the inclusion criteria, and comparisons were made between 232 consecutive patients without the use of tranexamic acid and 402 consecutive patients with the use of tranexamic acid. Patients were subdivided into 4 groups based on the complexity of revision surgical procedures: (1) major revision, (2) isolated femoral component revision, (3) isolated acetabular component revision, and (4) isolated femoral head and acetabular liner exchange. Within these groups, we compared the demographic data, estimated intraoperative blood loss, perioperative blood units transfused, postoperative hemoglobin drop, and thromboembolic complications between patients receiving either tranexamic acid or no antifibrinolytic therapy.

RESULTS

The primary outcomes of our study (estimated intraoperative blood loss, postoperative hemoglobin drop, and perioperative blood transfusion) were all reduced in patients who received tranexamic acid compared with patients who received no antifibrinolytic therapy. When analyzed on the basis of the complexity of surgical revision, there was a decrease in estimated intraoperative blood loss following tranexamic acid administration in the major revision group (845 compared with 1,095 mL; p < 0.001). The postoperative drop in hemoglobin was lower in the major revision group with tranexamic acid administration (by 8.9 g/L; p < 0.01) and the isolated acetabular component revision group with tranexamic acid administration (by 11.9 g/L; p < 0.001). The need for perioperative blood transfusion was reduced across all revisions treated with tranexamic acid (major revision group, 1.79 compared with 3.33 units, p < 0.001; femoral revision only, 0.97 compared with 2.25 units, p < 0.01; acetabular revision only, 0.73 compared with 1.72 units, p < 0.001; and head and liner exchange, 0.15 compared with 0.89 unit, p < 0.05).

CONCLUSIONS

Based on this study, preoperative administration of intravenous tranexamic acid in revision hip arthroplasty reduces allogenic blood transfusions and perioperative blood loss.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Intraoperative blood transfusion in pediatric patients undergoing renal transplant-Effect of renal graft size

In pediatric RT, donor allograft size often exceeds the expected recipient norms, especially in younger recipients. An "oversize" graft might not only present a technical- and space-related challenge, but may possibly lead to increased demands in perioperative volume requirements due to the disparity between donor and recipient in renal blood flow. We evaluated transfusion practices at a single tertiary institution with special consideration of kidney graft size, hypothesizing that oversize graft kidneys might lead to a quantifiable increased need of blood transfusion in smaller recipients. Retrospective analysis of all patients who underwent pediatric RT from January 2004 to June 2014 at a tertiary pediatric centre was performed. Variables analyzed included patient age, weight, pre- and postoperative Hb concentration, graft size, EBL, amount of intraoperative blood transfusion, and preoperative use of erythropoietin. Based on graft size in relation to patient's age, a SMR and an OvR were identified. A subcohort of age-matched pairs was used to allow for comparison between groups. We calculated the expected procedure- and transfusion-induced changes in Hb and compared these changes to the observed difference in pre- vs postoperative Hb to assess the influence of graft size on transfusion requirements. RT was performed in 188 pediatric recipients during the study period. In the matched cohort, percentage of transfused patients during transplantation in the OvR group was more than double compared with SMR (89% vs 39%, P < .001); similarly, the median number of transfused PRBC units in OvR was 1, while the median of SMR did not receive transfusion (P < .001). The difference between expected (calculated) and observed change in Hb was significantly higher in OvR with a median of 1.9 g/dL compared with SMR with a median of 1.0 g/dL (P = .026). Correspondingly, the calculated median volume taken up by a regular size kidney was significantly higher with 213 mL compared with 313 mL (P = .031) taken up by an oversize graft kidney. Median estimated intraoperative blood loss was significantly higher in OvR than in SMR (6.9 mL/kg, vs 5.3 mL/kg, respectively; P = .04). Median postoperative Hb was similar among groups (10.4 g/dL vs 10.6 g/dL for SMR vs OvR, respectively). Transplantation of an oversized kidney in pediatric RT recipients is associated with a quantifiable higher need for blood transfusion. This may be caused by a higher intraoperative EBL and/or greater blood volume sequestered by the larger renal allograft and requires further evaluation.

Defining the Tipping Point in Surgical Performance for Laparoscopic Donor Nephrectomy Among Transplant Surgery Fellows: A Risk-Adjusted Cumulative Summation Learning Curve Analysis

The United Network for Organ Sharing recommends that fellowship-trained surgeons participate in 15 laparoscopic donor nephrectomy (LDN) procedures to be considered proficient. The American Society of Transplant Surgeons (ASTS) mandates 12 LDNs during an abdominal transplant surgery fellowship. We performed a retrospective intraoperative case analysis to create a risk-adjusted cumulative summation (RACUSUM) model to assess the learning curve of novice transplant surgery fellows (TSFs). Between January 2000 and December 2014, 30 novice TSFs participated in the organ procurement rotation of our ASTS-approved abdominal transplant surgery fellowship. Measures of surgical performance included intraoperative time, estimated blood loss, and incidence of intraoperative complications. The performance of senior TSFs was used to benchmark novice TSF performance. Scores were tabulated in a learning curve model, adjusting for case complexity and prior TSF case volume. Rates of adverse surgical events were significantly higher for novice TSFs than for senior TSFs. In univariable analysis, multiple renal arteries, high BMI, prior abdominal surgery, male donor, and nephrolithiasis were correlated with higher incidence of adverse surgical events. Based on the RACUSUM model, high intraoperative time is mitigated after 28 procedures, incidence of intraoperative complications tends to diminish after 24 procedures, and improvement in estimated blood loss did not remain consistent. TSFs exhibit a tipping point in LDN performance by 24-28 cases and proficiency by 35-38 cases.

Total hip arthroplasty in patients with haemophilia - What are the risks of bleeding in the immediate peri-operative period?

BACKGROUND

Undergoing a major surgical intervention such as total hip arthroplasty (THA) with an underlying clotting disorder like haemophilia poses its own unique challenges. Despite the advances in factor replacement and medical management, the potential for excessive and uncontrolled haemorrhage still exists. The aim of this study was to quantify blood loss, peri-operative transfusion requirements and risk of haematoma formation in a cohort of patients with haemophilia undergoing THA.

METHODS

All patients with haemophilia types A or B who had undergone THA in the previous 10 years were identified from the Hospital In-Patient Enquiry system and theatre logs. A comprehensive review of operative records, laboratory parameters and peri-operative haematological management was conducted.

RESULTS

Eleven male patients (12 THA) were identified. The mean age was 56 years (range 28-76). The mean intra-operative blood loss was 502 ml (100-1250 ml) compared to an established normal blood loss of 400 ml. The mean drop in haemoglobin was 3.25 g/dl in 48 h. Only one patient required a post-operative transfusion of two units of red cell concentrate. There were no complications of haematoma formation.

CONCLUSION

The results in our institution compare favourably with the established blood loss reported in the literature and by assessment with International Guidelines. Average blood loss in patients with haemophilia was higher than the established normal, but there was no increased transfusion requirement.

A Comparison of Two Different Dosing Protocols for Tranexamic Acid in Posterior Spinal Fusion for Spinal Deformity: A Prospective, Randomized Trial

BACKGROUND

Multilevel spinal fusions have typically been associated with significant blood loss. Previous studies have shown a reduction in blood loss with antifibrinolytics in both adolescent and adult spinal deformity patients. While this has been mirrored in other subspecialties as well, the dosing of TXA remains highly variable. To date, there remains a paucity of data guiding dosing for TXA in spine surgery and orthopedic surgery as a whole.

METHODS/DESIGN

One hundred and fifty patients from 3 institutions (50 each site) will be consecutively enrolled and randomized to either a high dose of TXA (50mg/kg loading followed by 20mg/kg hourly) or a lose dose (10mg/kg, then 1mg/kg hourly). Both surgeons and patients will be blinded to the treatment group. Primary outcomes will be perioperative blood loss, drain output, and transfusion rate. Secondary outcomes will be length of stay, complications, and overall cost.

DISCUSSION

The primary goal of this study is to provide level-1 comparative data for two TXA dosing regimens in adult spinal deformity surgery. Management of blood loss remains a critical factor in reducing complications during spinal deformity surgery. The null hypothesis is that there is no difference between high- and low-dose TXA with respect to any of the primary or secondary outcomes.

Predicting postoperative day 1 hematocrit levels after uncomplicated hysterectomy

OBJECTIVE

To develop a model for predicting postoperative hematocrit levels after uncomplicated hysterectomy.

METHODS

In a retrospective study, data were analyzed from the Michigan Surgery Quality Collaborative for non-emergent hysterectomies performed for benign indications among women aged at least 18 years between January 1, 2012, and April 4, 2014. Linear mixed models were used for univariate and multivariate analyses.

RESULTS

The model was developed with data from 4747 hysterectomies and validated on 1184 cases. In the mixed multivariate analysis, higher postoperative day 1 (POD1) hematocrit levels were associated with higher weight (B=0.03222, P<0.001), higher preoperative hematocrit (B=0.6587, P<0.001), and non-vaginal hysterectomy (B=0.2815, P=0.0055). Lower POD1 hematocrit was associated with higher preoperative platelet count (B=-0.00457, P<0.001), greater estimated blood loss (B=-0.00652, P<0.001), and larger intraoperative crystalloid volume (B=-0.3303, P<0.001). The final model predicted POD1 hematocrit within 4% points of the actual value for 91.7% of cases in the validation set.

CONCLUSION

Use of the model after uncomplicated hysterectomy might help to support the practice of selectively conducting postoperative hematocrit tests after hysterectomy in a clinically thoughtful and cost-effective manner.

Incidence of perioperative events in single setting bilateral direct anterior approach total hip arthroplasty

The peri-operative complication rates of a single setting bilateral direct anterior approach (DAA) total hip arthroplasty (THA) are not well known. All single setting (90) bilateral DAA THA patients were reviewed. Blood loss was 632 mL for single setting bilateral DAA procedures. Intra-operative and post-operative complication rates for single setting bilateral DAA THA were low.

Optimal schedule of preoperative embolization for spinal metastasis surgery

STUDY DESIGN

A retrospective study.

OBJECTIVE

To investigate the relationship between intraoperative blood loss during spinal metastasis surgery and the surgical delay after preoperative embolization.

SUMMARY OF BACKGROUND DATA

Delaying surgery after embolization is thought to diminish its effectiveness because of revascularization, but there has been no scientific study that supports this hypothesis.

METHODS

We reviewed data from 66 consecutive posterior palliative decompression surgical procedures for spinal metastasis from thyroid and renal cell carcinoma (39 thyroid and 27 renal) in 58 patients between 2004 and 2012. All patients underwent preoperative angiography. The timing of preoperative embolization was determined on the basis of the operating room and interventional radiologist schedules. Excluding one case who did not receive embolization due to lack of hypervascularity, we analyzed 65 cases to compare intraoperative blood loss according to the completeness of embolization and the time lapse between embolization and surgery.

RESULTS

Surgical procedures were performed on the same day of embolization in 21 cases (same day-group), and on the next day after embolization in 39 cases (next-day group). Five surgical procedures were performed 2 days later. The intraoperative blood loss was significantly lesser with complete embolization than with partial embolization (mean ± standard deviation: 809 ± 835 vs. 1210 ± 904 mL, P = 0.03). Among those with complete embolization, the intraoperative blood loss as well as the perioperative transfusion requirement was significantly lesser in the same-day group than in the next-day group (mean ± standard deviation: blood loss: 433 ± 376 vs. 1012 ± 974 mL, P = 0.01; transfusion requirement: 1.5 ± 1.7 vs. 4.2 ± 4.1 units, P = 0.04).

CONCLUSION

Preoperative embolization showed greater effectiveness in reducing intraoperative blood loss when surgery for spinal metastasis was performed on the same day than when surgery was delayed. Surgery should be performed on the same day of embolization if possible.

LEVEL OF EVIDENCE

4.

Acute transfusion practice during trauma resuscitation: who, when, where and why?

BACKGROUND

Early transfusion (ET=within 24h) has been shown to be required in approximately 5% of trauma patients. Critical care transfusion guidelines control transfusion triggers by evidence based cut-offs. Empirical guidelines influence decision making for ET in trauma.

AIM

to describe the patterns, indications and timing of ET at level 1 trauma centre.

METHODS

A 12-month prospective study was performed on all trauma admissions requiring ET. Demographics, mechanism, injury severity (ISS) were collected. Timing, location, volume, the clinician initiating first unit of transfusion, reason for transfusion was recorded, with corresponding blood gas results and physiological parameters. Mortality, ICU admission, length of stay, need for emergent surgery were outcomes.

RESULTS

From 965 trauma admissions 91 (9%) required ET (76% male, median age: 38 (10-88, IQR: 22-59), blunt mechanism: 87%, ISS: 25 (4-66, IQR: 16-34). 43% (39/91) had massive transfusion protocol (MTP) activation. ET was initiated in ED (52%), OR (38%) or ICU (10%). MTP transfusions were started at a median of 0.5h (0.5-4, IQR: 0.5-1.5), whilst non-MTP transfusions were initiated at a median 3h (0.5-23, IQR: 2-9). The first unit of ET was initiated by trauma surgeon (35%), anaesthetist (30%), ED (19%), ICU (13%) and general surgeon (3%). Transfusions triggers at the first unit of transfusion were 'expected or ongoing bleeding' 29%, dropping haemoglobin 26%, haemorrhagic shock 24%, hypotension 10%, tachycardia 8%. Median systolic blood pressure was 90 (45-125, IQR: 80-100), heart rate was 100 (53-163, IQR: 80-120), haemoglobin was 96 (50-166, IQR: 85-114)g/l and base excess was -4.2(-22.1 to 2.7, IQR: -7.2 to 2.4)mmol/l at the time of transfusion. Emergency surgery was required in 86% (78/91). ICU admission rate was 69% (63/91). Mortality was 14%. Low volume transfusion (1-2 units) was more likely to lead to overtransfusion (Hb>110 g/l).

CONCLUSION

The prospective evaluation of acutely transfused trauma patients showed a distinct pattern of transfusion triggers as the patient passes from ED to the OT and arrives to the ICU. The conventional transfusion trigger (haemoglobin level) is not appropriate in ET as early transfusion triggers are based on vital signs, blood gas results, injury patterns and anticipated major bleeding.

Does early fixation of posterior wall acetabular fractures lead to increased blood loss?

OBJECTIVE

Controversy exists regarding the ideal timing of acetabular fracture surgery. Surgery within the first 24 hours might put patients at risk for increased blood loss; however, early treatment might facilitate fracture reduction and patient mobilization. The purpose of this study was to determine whether early surgery for posterior wall acetabular fractures results in higher intraoperative blood loss.

DESIGN

Retrospective review.

SETTING

Level I academic trauma center.

METHODS

A 1-year retrospective review of 49 consecutive posterior wall acetabular fractures from a single Level I trauma center. Outcome variables were analyzed with t tests, Pearson correlation coefficient, and multiple linear regression analysis.

INTERVENTION

Surgery for posterior wall acetabular fractures.

MAIN OUTCOME MEASURES

Estimated blood loss (EBL), preoperative and postoperative hematocrit levels, and intraoperative and postoperative blood product requirements as a function of the timing of surgery.

RESULTS

No difference in EBL was shown between the fractures fixed within 24 hours of injury (mean = 644 mL) and those fixed later (573 mL, P = 0.50). No difference was observed when analyzing timing of surgery as a continuous variable (P = 0.45) or other outcome variables. A post hoc power analysis demonstrated that our sample could detect a difference in EBL of 166 mL.

CONCLUSIONS

Our study suggests that posterior wall fractures might be a subset of acetabular fractures that can be treated immediately without increased risk of excessive blood loss. It should be emphasized that our findings should not be applied to other more complex types of fractures of the acetabulum.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Does the intraoperative tranexamic acid decrease operative blood loss during posterior spinal fusion for treatment of adolescent idiopathic scoliosis?

STUDY DESIGN

Retrospective, observational study.

OBJECTIVE

To assess the efficacy and safety of tranexamic acid (TXA) in decreasing operative blood loss and the need for transfusion during posterior spinal fusion for the treatment of idiopathic scoliosis in adolescents.

SUMMARY OF BACKGROUND DATA

Blood loss associated with spinal surgery is a common potential cause of morbidity and often requires a blood transfusion, which subjects patients to the known risks of blood transfusion including transmission of diseases. Since the 1990s, intraoperative administration of antifibrinolytics has gained popularity. This study assesses the efficacy and safety of TXA in controlling blood loss during posterior spinal fusion for the treatment of idiopathic scoliosis in adolescents at 1 institution.

METHODS

A retrospective comparative analysis of 106 consecutive adolescents undergoing posterior spinal fusion procedures at 1 institution was performed. Patients were analyzed according to treatment group: controls (63) and TXA (43). There were no significant differences in demographic (age, sex, and comorbidities) or surgical traits (surgical time, number of fused vertebrae, preoperative hematocrit and hemoglobin) between the 2 groups.

RESULTS

TXA group had significantly less intraoperative blood loss (613 ± 195 mL) than the control group (1079 ± 421 mL; P < 0.001) as well as postoperative blood loss (155 ± 86 mL and 263 ± 105 mL, respectively; P < 0.001). TXA group received significantly less blood during the surgical procedure than the control group (258 ± 246 mL and 377 ± 200 mL, respectively; P < 0.001). There were no major intraoperative complications for any of the treatment groups.

CONCLUSION

TXA treatment group lost significantly less blood and received significantly fewer blood transfusions than the control group without significant differences in intra- and postoperative complications. A multicenter randomized prospective analysis would provide additional information of the efficacy and safety of TXA.

A prospective, randomized, double-blinded single-site control study comparing blood loss prevention of tranexamic acid (TXA) to epsilon aminocaproic acid (EACA) for corrective spinal surgery

BACKGROUND

Multilevel spinal fusion surgery has typically been associated with significant blood loss. To limit both the need for transfusions and co-morbidities associated with blood loss, the use of anti-fibrinolytic agents has been proposed. While there is some literature comparing the effectiveness of tranexamic acid (TXA) to epsilon aminocaproic acid (EACA) in cardiac procedures, there is currently no literature directly comparing TXA to EACA in orthopedic surgery.

METHODS/DESIGN

Here we propose a prospective, randomized, double-blinded control study evaluating the effects of TXA, EACA, and placebo for treatment of adolescent idiopathic scoliosis (AIS), neuromuscular scoliosis (NMS), and adult deformity (AD) via corrective spinal surgery. Efficacy will be determined by intraoperative and postoperative blood loss. Other clinical outcomes that will be compared include transfusion rates, preoperative and postoperative hemodynamic values, and length of hospital stay after the procedure.

DISCUSSION

The primary goal of the study is to determine perioperative blood loss as a measure of the efficacy of TXA, EACA, and placebo. Based on current literature and the mechanism by which the medications act, we hypothesize that TXA will be more effective at reducing blood loss than EACA or placebo and result in improved patient outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT00958581.

Estimating blood loss: comparative study of the accuracy of parents and health care professionals

OBJECTIVE

Hematemesis and hematochezia are not uncommon presenting complaints in children. The amount of blood loss reported by the parent is likely to influence the pediatrician's decision regarding investigations and management. Currently, there are only very limited data regarding the ability of laypersons to estimate blood losses visually. This study investigated the accuracy of parents, in comparison to pediatric health care professionals, in estimating blood loss volumes.

PATIENTS AND METHODS

We performed a prospective, single-blinded study including 227 participants, comprising 131 parents, 58 nurses, and 38 doctors. Participants visually estimated the volume of 1 randomly allocated sample from each of the 2 categories: (1) 1, 5, or 10 mL of artificial blood applied to a diaper (simulated hematochezia) and (2) 5, 10, or 50 mL placed in a kidney-dish (simulated hematemesis). An "error factor" (=, estimated volume/actual volume shown) was used to facilitate comparisons.

RESULTS

Parents provided the most inaccurate estimates overall, although individual accuracy varied considerably. The largest overestimate (518 mL) and the highest error factor (23.4) were recorded in a parent; overall, 71% of the estimates provided by parents were overestimates. The highest proportion of accurate estimates (+/-50% of actual volume) was recorded by nurses (29%). Doctors had a tendency to underestimate volumes (62% of the estimates were less than half the actual volume). However, there was no statistically significant difference between the performance of nurses and doctors. Health care professionals tended to overestimate small volumes and underestimate large volumes. Professional experience had no relevant impact on accuracy, nor did parental gender or age.

CONCLUSIONS

Visual estimation of blood losses is highly inaccurate, both by laypersons and by health care professionals. Physicians should, therefore, base management decisions primarily on clinical findings and not overly rely on the history provided, or their own estimates.

Transfusion trigger--how precise are we? Intraoperative blood transfusion practices in a tertiary centre in Nigeria

SUMMARY

To determine how well anaesthetists in Nigeria determine the need for transfusion based solely on physiological variables and estimated blood loss. To determine the incidence of inappropriate blood transfusion. Anaesthetists in our hospital determine when to transfuse patients based solely on clinical acumen. This may result in inappropriate transfusion especially in this subregion where blood donors are scarce and risk of transmission of infection high. All surgical patients requiring blood transfusion were prospectively studied over 3 months. Transfusion was based solely on the discretion of the attending anaesthetist. Haemoglobin (Hb) concentration was measured prior to transfusion and 24 h postoperatively. Appropriate transfusion was defined as blood transfusion at Hb < 8 g dL(-1) or 10 g dL(-1) in the elderly and those with medical comorbidities. The trigger for transfusion was documented as well as estimated blood loss. Thirty-four patients were studied. The mean pretransfusion Hb was 8.09 +/- 2.45 g dL(-1) (range 4.6-14.2). Twenty-one patients (61.8%) had appropriate blood transfusion. The commonest transfusion triggers were clinical pallor (82.4%), excessive blood loss (76.4%), delayed capillary refill (55.9%) and severe hypotension (50%). The use of near patient monitoring devices might further improve blood transfusion practice in this setting where donor blood is scarce.

Development of an index to characterize the "invasiveness" of spine surgery: validation by comparison to blood loss and operative time

STUDY DESIGN

Prospective cohort study.

OBJECTIVE

To create and validate an index describing the extent of spine surgical intervention to allow fair comparisons of complication rates among patients treated by different surgeons, devices, or hospitals.

SUMMARY OF BACKGROUND DATA

Safety comparisons in spine surgery are limited by lack of methods that adjust for important variations in the surgical "case-mix." Among other factors, the magnitude of an operation is likely to have a substantial influence on the likelihood of complications.

METHODS

We created a spine surgery invasiveness index defined as the sum, across all vertebral levels, of 6 possible interventions on each operated vertebra: anterior decompression, anterior fusion, anterior instrumentation, posterior decompression, posterior fusion, and posterior instrumentation. We assessed the validity of this index by examining its association with blood loss and surgery duration in 1723 spine surgeries, adjusting for important factors including age, gender, body mass index, diagnosis, neurologic deficit, revision surgery, and vertebral level of surgery.

RESULTS

Blood loss increased by 11.5% and surgery duration increased by 12.8 minutes for each unit increase in the invasiveness index. The invasiveness index explained 44% of the variation in blood loss and 52% of the variation in surgery duration. For specific surgical components, blood loss increased by 9.4% and surgery duration by 11.4 minutes for each vertebral level of anterior decompression, 19.4% and 33.8 minutes for each segment of anterior instrumentation, 12.9% and 22.7 minutes for each level of posterior decompression, and 25.1% and 18.8 minutes for each segment of posterior instrumentation.

CONCLUSION

An "invasiveness" index based on the number of vertebrae decompressed, fused, or instrumented showed the expected associations with both blood loss and surgery duration. This quantitative description of surgery invasiveness may be useful to adjust for surgical variations when making safety comparisons in spine surgery.

The effect of perioperative anemia on clinical and functional outcomes in patients with hip fracture

OBJECTIVES

To describe the epidemiology of perioperative anemia in patients with hip fracture and assess the relationship between the hemoglobin measurements and clinical outcomes.

DESIGN

Prospective observational cohort study.

SETTING

Four university and community teaching hospitals.

PATIENTS

A consecutive cohort of 550 patients who underwent surgery for hip fracture and survived to discharge from August 1997 and August 1998 were evaluated and followed prospectively.

MAIN OUTCOME MEASURES

Deaths, readmissions and Functional Independence Motor mobility scores within 60 days of discharge.

RESULTS

Anemia (defined as hemoglobin <12.0 g/dL) was present in 40.4% of patients on admission, 45.6% at the presurgery nadir, 93.0% at the postsurgery nadir, and 84.6% near discharge. The mean drop in hemoglobin after surgery was 2.8 +/- 1.6 g/dL. In multivariate analyses, higher hemoglobin levels on admission were associated with shorter lengths of hospital stay and lower odds of death and readmission even after controlling for a broad range of prefracture patient characteristics, clinical status on discharge, and use of blood transfusion. Admission and preoperative anemia was not associated with risk-adjusted Functional Independence Motor mobility scores. In multivariable analyses, higher postoperative hemoglobin was associated with shorter length of stay and lower readmission rates, but did not effect rates of death or Functional Independence Motor mobility scores.

CONCLUSIONS

Substantial declines in hemoglobin were common in patients with hip fracture. Higher preoperative hemoglobin was associated with shorter length of stay and lower odds of death and readmission within 60 days of discharge. Postoperative hemoglobin was also related to length of stay and readmission rates.