A reduction in type and screen: preoperative prediction of RBC transfusions in surgery procedures with intermediate transfusion risks

Presurgical circulating platelet-derived microparticles level as a risk factor of blood transfusion in patients with valve heart disease undergoing cardiac surgery

BACKGROUND

Cell-derived microparticles (MPs) are membrane vesicles that have emerged as a potential biomarker for various diseases and their clinical complications. This study investigates the role of MPs as a risk factor for blood transfusion in patients with valve heart disease undergoing cardiac surgery.

METHODS

Forty adult patients undergoing heart valve surgery with cardiopulmonary bypass (CPB) were enrolled, and venous blood samples were collected prior to surgical incision. Plasma rich in MPs was prepared by double centrifugation, and the concentration of MPs was determined using the Bradford method. Flow cytometry analysis was performed to determine MPs count and phenotype. Patients were divided into "with transfusion" (n = 18) and "without transfusion" (n = 22) groups based on red blood cell (RBC) transfusion.

RESULTS

There was no significant difference in MPs concentration between the "with transfusion" and "without transfusion" groups. Although the count of preoperative platelet-derived MPs (PMPs), monocyte-derived MPs (MMPs), and red cell-derived MPs (RMPs) was higher in "without transfusion" group, these differences were not statistically significant. The preoperative PMPs count was negatively correlated with RBC transfusion (P = 0.005, r = -0.65). Multivariate logistic regression analysis revealed that the count of CD41+ PMPs, Hemoglobin (Hb), and RBC count were risk factors for RBC transfusion.

CONCLUSION

This study suggests that the presurgical levels of PMPs, Hb, and RBC count can serve as risk factors of RBC transfusion in patients with valve heart disease undergoing cardiac surgery. The findings provide insights into the potential use of MPs as biomarkers for blood transfusion prediction in cardiac surgery.

Cost-effectiveness of routine type and screens in select urological surgeries

PURPOSE

To evaluate the cost-effectiveness of obtaining a preoperative type and screen (T/S) for common urologic procedures.

METHODS

A decision tree model was constructed to track surgical patients undergoing two preoperative blood ordering strategies as follows: obtaining a preoperative T/S versus not doing so. The model was applied to the National (Nationwide) Inpatient Sample (NIS) data, from January 1, 2006 to September 30, 2015. Cost estimates for the model were created from combined patient-level data with published costs of a T/S, type and crossmatch (T/C), a unit of pRBC, and one unit of emergency-release transfusion (ERT). The primary outcome was the incremental cost per ERT prevented, expressed as an incremental cost-effectiveness ratio (ICER) between the two preoperative blood ordering strategies. A cost-effectiveness analysis determined the ICER of obtaining preoperative T/S to prevent an emergency-release transfusion (ERT), with a willingness-to-pay threshold of $1,500.00.

RESULTS

A total of 4,113,144 surgical admissions from 2006 to 2015 were reviewed. The overall transfusion rate was 10.54% (95% CI, 10.17-10.91) for all procedures. The ICER of preoperative T/S was $1500.00 per ERT prevented. One-way sensitivity analysis demonstrated that the risk of transfusion should exceed 4.12% to justify preoperative T/S.

CONCLUSION

Routine preoperative T/S for radical prostatectomy (rate = 3.88%) and penile implants (rate = .91%) does not represent a cost-effective practice for these surgeries. It is important for urologists to review their institution T/S policy to reduce inefficiencies within the preoperative setting.

Selective type & screen for elective colectomy based on a transfusion risk score may generate substantial cost savings

BACKGROUND

Preoperative type and screen are currently recommended for all patients undergoing colectomy. We aimed to identify risk factors for transfusion and define a low-risk cohort of patients undergoing colectomy in whom type and screen may be safely avoided.

METHODS

We identified all patients undergoing elective colectomy in the National Surgical Quality Improvement Project-Targeted Colectomy files from 2012 to 2016. Patients transfused preoperatively and those undergoing other concurrent major abdominal procedures were excluded. We compared patients who received blood transfusion on the day of surgery to those who did not. Half of the cohort was randomly selected for development of a points-based model predicting blood transfusion on the day of surgery. This model was then validated using the remaining patients.

RESULTS

Of 61,964 patients undergoing colectomy, 3128 (5%) patients were transfused with 1290 (2.1%) occurring on the day of surgery. Preoperative anemia was the strongest predictor of blood transfusion on the day of surgery. Among patients with hematocrit > 35%, day of surgery transfusion risk was 0.8%; 99% of patients with hematocrit > 35% had a score 20 or less. Selective type and screen for patients with score ≤ 20 or hematocrit > 35% would avoid type and screen in 91% and 81% of patients, respectively.

CONCLUSION

Transfusion following elective colectomy is rare and can be accurately predicted by preoperative patient characteristics. Selective type and screen based on these parameters have the potential to prevent operative delays and lower cost.

A novel model forecasting perioperative red blood cell transfusion

We aimed to establish a predictive model assessing perioperative blood transfusion risk using a nomogram. Clinical data for 97,443 surgery patients were abstracted from the DATADRYAD website; approximately 75% of these patients were enrolled in the derivation cohort, while approximately 25% were enrolled in the validation cohort. Multivariate logical regression was used to identify predictive factors for transfusion. Receiver operating characteristic (ROC) curves, calibration plots, and decision curves were used to assess the model performance. In total, 5888 patients received > 1 unit of red blood cells; the total transfusion rate was 6.04%. Eight variables including age, race, American Society of Anesthesiologists' Physical Status Classification (ASA-PS), grade of kidney disease, type of anaesthesia, priority of surgery, surgery risk, and an 18-level variable were included. The nomogram achieved good concordance indices of 0.870 and 0.865 in the derivation and validation cohorts, respectively. The Youden index identified an optimal cut-off predicted probability of 0.163 with a sensitivity of 0.821 and a specificity of 0.744. Decision curve (DCA) showed patients had a standardized net benefit in the range of a 5–60% likelihood of transfusion risk. In conclusion, a nomogram model was established to be used for risk stratification of patients undergoing surgery at risk for blood transfusion. The URLs of web calculators for our model are as follows: http://www.empowerstats.net/pmodel/?m=11633_transfusionpreiction.

Personalized Surgical Transfusion Risk Prediction Using Machine Learning to Guide Preoperative Type and Screen Orders

BACKGROUND

Accurate estimation of surgical transfusion risk is essential for efficient allocation of blood bank resources and for other aspects of anesthetic planning. This study hypothesized that a machine learning model incorporating both surgery- and patient-specific variables would outperform the traditional approach that uses only procedure-specific information, allowing for more efficient allocation of preoperative type and screen orders.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program Participant Use File was used to train four machine learning models to predict the likelihood of red cell transfusion using surgery-specific and patient-specific variables. A baseline model using only procedure-specific information was created for comparison. The models were trained on surgical encounters that occurred at 722 hospitals in 2016 through 2018. The models were internally validated on surgical cases that occurred at 719 hospitals in 2019. Generalizability of the best-performing model was assessed by external validation on surgical cases occurring at a single institution in 2020.

RESULTS

Transfusion prevalence was 2.4% (73,313 of 3,049,617), 2.2% (23,205 of 1,076,441), and 6.7% (1,104 of 16,053) across the training, internal validation, and external validation cohorts, respectively. The gradient boosting machine outperformed the baseline model and was the best- performing model. At a fixed 96% sensitivity, this model had a positive predictive value of 0.06 and 0.21 and recommended type and screens for 36% and 30% of the patients in internal and external validation, respectively. By comparison, the baseline model at the same sensitivity had a positive predictive value of 0.04 and 0.144 and recommended type and screens for 57% and 45% of the patients in internal and external validation, respectively. The most important predictor variables were overall procedure-specific transfusion rate and preoperative hematocrit.

CONCLUSIONS

A personalized transfusion risk prediction model was created using both surgery- and patient-specific variables to guide preoperative type and screen orders and showed better performance compared to the traditional procedure-centric approach.

EDITOR’S PERSPECTIVE

Cost-Effectiveness of Routine Type and Screens in Select Endonasal Skull Base Surgeries

Objective The study aimed to evaluate the cost-effectiveness of obtaining preoperative type and screens (T/S) for common endonasal skull base procedures, and determine patient and hospital factors associated with receiving blood transfusions.

Study Design Retrospective database analysis of the 2006 to 2015 National (nationwide) Inpatient Sample and cost-effectiveness analysis.

Main Outcome Measures Multivariate regression analysis was used to identify factors associated with transfusions. A cost-effectiveness analysis was then performed to determine the incremental cost-effectiveness ratio (ICER) of obtaining preoperative T/S to prevent an emergency-release transfusion (ERT), with a willingness-to-pay threshold of $1,500.

Results A total of 93,105 cases were identified with an overall transfusion rate of 1.89%. On multivariate modeling, statistically significant factors associated with transfusion included nonelective admission (odds ratio [OR]: 2.32; 95% confidence interval [CI]: 1.78–3.02), anemia (OR: 4.42; 95% CI: 3.35–5.83), coagulopathy (OR: 4.72; 95% CI: 2.94–7.57), diabetes (OR: 1.45; 95% CI: 1.14–1.84), liver disease (OR: 2.37; 95% CI: 1.27–4.43), pulmonary circulation disorders (OR: 3.28; 95% CI: 1.71–6.29), and metastatic cancer (OR: 5.85; 95% CI: 2.63–13.0; p < 0.01 for all). The ICER of preoperative T/S was $3,576 per ERT prevented. One-way sensitivity analysis demonstrated that the risk of transfusion should exceed 4.12% to justify preoperative T/S.

Conclusion Routine preoperative T/S does not represent a cost-effective practice for these surgeries using nationally representative data. A selective T/S policy for high-risk patients may reduce costs.

Postoperative variations in anaemia treatment and transfusions (POSTVenTT): protocol for a prospective multicentre observational cohort study of anaemia after major abdominal surgery

AIM

Perioperative anaemia is common and is associated with increased postoperative complications, delayed recovery and increased morbidity and mortality. However, current management of anaemia after surgery is variable. This student- and trainee-led collaborative study aims to audit the postoperative variations in anaemia treatment and transfusions (POSTVenTT) and quantify its impact on patient outcomes after major abdominal surgery.

METHOD

This is the first Australian and Aotearoa New Zealand multicentre study in surgical patients conducted by networks of trainees, students and consultants. Data will be prospectively collected on consecutive adult patients undergoing elective and emergency major abdominal surgery with follow-up to 30 days after hospital discharge. The primary endpoint will be adherence to anaemia management guidelines. Secondary outcomes will include postoperative anaemia, blood transfusion, postoperative complications as per the Clavien-Dindo classification, length of stay and hospital readmission at 30 days.

DISCUSSION

This protocol describes the first Australian and Aotearoa New Zealand collaborative study by medical students and surgical trainees. The collaboration will aim to provide a clear understanding of current practices regarding the management and risk factors for anaemia and association with patient outcomes after major abdominal surgery.

Examining the Utility and Cost of Routine Type and Screen Prior to Minimally Invasive Hysterectomy

Background and Objectives:

Pre-operative type and screen (T&S) is typically obtained if a patient is expected to require a blood transfusion; however, in cases of minimal blood loss, routine T&S may be unnecessary. The objective of our study was to examine the utility and cost of routine pre-operative T&S prior to minimally invasive hysterectomies (MIH).

Methods:

We performed a retrospective chart review of all MIH from January 1, 2018 to December 31, 2019. Patient demographics and surgical parameters were abstracted. The proportion of MIH with a preoperative T&S was compared to the rate of peri-operative blood transfusion. Statistical tests were used where appropriate. Logistic regression was used to examine the relationship between pre-operative hemoglobin (Hgb) and peri-operative transfusion.

Results:

Patients (n = 307) with a mean age of 54 (standard deviation = 12.6) underwent MIH. T&S was ordered in 42.7% of cases, with 2.9% requiring a blood transfusion. Two-thirds of women receiving a transfusion had a history of anemia (p = .004). Women with a pre-operative Hgb < 10.6 gm/dL (n = 30) had a 27% probability of a transfusion, while those with a pre-operative Hgb > 10.6 gm/dL (n = 264) had a 99% probability of no transfusion. A T&S costs ∼$190 at our institution; if routine T&S was eliminated prior to MIH, cost savings is projected to be ∼$11,590 annually.

Conclusion:

Approximately 42.7% of MIH had T&S ordered, but only 2.9% received transfusions. Most patients who required a transfusion had a history of anemia. Significant cost savings could be incurred if routine T&S was eliminated prior to MIH.

Preoperative prediction of Bleeding Independently associated with Mortality after noncardiac Surgery (BIMS): an international prospective cohort study

BACKGROUND

Diagnostic criteria for Bleeding Independently associated with Mortality after noncardiac Surgery (BIMS) have been defined as bleeding that leads to a postoperative haemoglobin <70 g L^-1, leads to blood transfusion, or is judged to be the direct cause of death. Preoperative prediction guides for BIMS can facilitate informed consent and planning of perioperative care.

METHODS

In a prospective cohort study of 16 079 participants aged ≥45 yr having inpatient noncardiac surgery at 12 academic hospitals in eight countries between 2007 and 2011, 17.3% (2782) experienced BIMS. An electronic risk calculator for BIMS was developed and internally validated by logistic regression with bootstrapping, and further simplified to a risk index. Decision curve analysis assessed the potential utility of each prediction guide compared with a strategy of identifying risk of BIMS based on preoperative haemoglobin <120 g L^-1.

RESULTS

With information about the type of surgery, preoperative haemoglobin, age, sex, functional status, kidney function, history of high-risk coronary artery disease, and active cancer, the risk calculator accurately predicted BIMS (bias-corrected C-statistic, 0.84; 95% confidence interval, 0.837-0.852). A simplified index based on preoperative haemoglobin <120 g L^-1, open surgery, and high-risk surgery also predicted BIMS, but less accurately (C-statistic, 0.787; 95% confidence interval, 0.779-0.796). Both prediction guides could improve decision making compared with knowledge of haemoglobin <120 g L^-1 alone.

CONCLUSIONS

BIMS, defined as bleeding that leads to a postoperative haemoglobin <70 g L^-1, leads to blood transfusion, or that is judged to be the direct cause of death, can be predicted by a simple risk index before surgery.

CLINICAL TRIAL REGISTRATION

NCT00512109.

The Utility of ABO Testing in Pediatric Patients Undergoing Elective Surgery

BACKGROUND

Patients for elective operation often undergo routine ABO/Rh type and screening test for potential need of transfusion. Some institutions require double verification of ABO/Rh type. We evaluated the clinical practice pattern of performing ABO/Rh type and screening test in pediatric patients undergoing elective operation.

METHODS

Electronic medical records from pediatric patients who underwent elective surgery between June 2006 and June 2010 were retrieved. The frequency of ABO/Rh type and screening test and the incidence of packed red blood cell (pRBC) request and pRBC dispatch from the blood bank among those tested were analyzed by year and the surgical department.

RESULTS

Of the 23,631 patients, the incidence of ABO/Rh type and screening was 32.2%, and pRBC was dispatched in 37.9% of these patients. The incidence of ABO/Rh type and screening varied between 1.5% and 97.9% among surgical departments and also within the surgical departments depending on the type of surgery. The incidence of ABO/Rh type and screening showed a decreasing trend over the study period.

CONCLUSIONS

There was significant variability among and within the surgical departments in the incidence of ABO/Rh type and screening in children undergoing elective surgery. A tailored approach may be beneficial to the patient in terms of comfort and cost.

Development of a prediction model for allogenic blood transfusion in children undergoing surgery for developmental dysplasia of the hip

BACKGROUND

Blood transfusion is a common practice, but it is not without cost and risk. A model that predicts the risk of blood transfusion could guide informed preoperative blood ordering and use of blood loss preventive measures.

OBJECTIVE

This study aimed to develop a prediction model of blood transfusion in children with developmental dysplasia of the hip (DDH) undergoing surgery.

METHODS

A retrospective cohort of DDH patients from 2008 to 2017. The included patients were between 1 to 9 years old, underwent anterior open reduction and/or acetabular osteotomy with and without femoral shortening. The unit of analysis was undergoing such an operation. The outcome was allogenic blood transfusion. Potential predictors were age, sex, body mass index (BMI), international hip dysplasia institute grade, type of surgery, intervention bilaterally during the same operative session, primary versus reoperation surgery, the addition of regional anaesthesia, preoperative haemoglobin and hematocrit.

RESULTS

A total of 524 patients who met the inclusion criteria underwent 721 operative sessions. The median age (interquartile range) at operation was 23 (20-33) months. The blood transfusion rate was 11.8%. Independent predictors were lower preoperative haemoglobin, reduced BMI, simultaneous bilateral surgery and the extent of surgical treatment.

CONCLUSIONS

The developed prognostic model allows prediction for blood transfusion in DDH patients undergoing surgery.

An audit of perioperative blood transfusions in a regional hospital to rationalise a maximum surgical blood ordering schedule

Appropriate preoperative blood typing and cross-matching is an important quality improvement target to minimise costs and rationalise the use of blood bank resources. This can be facilitated using a maximum surgical blood ordering schedule (MSBOS) for specific operations. It is recommended that individual hospitals develop a site-specific MSBOS based on institutional data, but this is challenging in non-tertiary centres without electronic databases. Our aim was to audit our perioperative blood transfusions to develop a site-specific MSBOS. A retrospective audit of blood transfusions in surgical patients in our regional referral hospital was conducted using five years' coded administrative data. Procedures with higher transfusion rates warranting preoperative testing (type and screen with or without subsequent cross-matching) were identified. There were about 15,000 eligible surgical procedures performed in our institution over the audit period. The need for preoperative testing was identified for only a few procedures, namely laparotomy, bowel resection, major amputation, joint arthroplasty, hip/femur fracture and humerus surgery, and procedures for obstetric complications. We observed a reduction in transfusion rates over time for total joint arthroplasty. The use of coding data represents an efficient method by which centres without electronic anaesthesia information management systems can conduct large-scale audits to develop a site-specific MSBOS. This would represent a significant improvement for hospitals that currently base preoperative testing recommendations on expert opinion alone. As many procedures in regional centres have very low transfusion rates, hospitals with a similar case mix to ours could consider selectively auditing higher-risk operations where local data is most likely to alter testing recommendations.

Cost effectiveness of preoperative screening for healthy patients undergoing robotic hysterectomy

The objective of this study was to determine whether routine preoperative type and screen blood testing is cost effective and medically warranted for benign diagnosis in healthy patients undergoing robotic hysterectomy. The study was designed as a cross sectional retrospective descriptive study. Four hundred and twenty two medical records of American Society of Anesthesiologists (ASA) Classifications I and II patients undergoing robotically-assisted laparoscopic hysterectomy between 1 June 2011 and 31 May 2014 at a 211 bed regional medical center were analysed. The results from this study paralleled the findings of other published research. Preoperative type and screen testing was performed on 249 (59%) of the patients in the study. Ten patients (2.4% of the group) converted to open laparotomy. Mean estimated blood loss was 59.59ml. No perioperative transfusions were required. The results indicate that preoperative type and screen testing is not warranted for patients meeting the inclusion criteria.

Transfusion Rates and the Utility of Type and Screen for Pelvic Organ Prolapse Surgery

OBJECTIVES

Limited data exist directly comparing the likelihood of blood transfusion by route of apical pelvic organ prolapse (POP) surgery. In addition, limited evidence is available regarding the risk of not ordering preoperative type and screen (T&S) in apical POP surgery. The objectives of the study are to (1) provide baseline data regarding the current need for preoperative T&S by comparing perioperative blood transfusion rates between 3 routes of apical POP surgery and (2) determine the rate of a positive preoperative antibody screen in women who underwent apical POP surgery.

METHODS

This was a retrospective cohort study of women who underwent apical POP surgery by 3 different routes: abdominal (abdominal sacrocolpopexy), robotic (robotic sacrocolpopexy), or vaginal (uterosacral or sacrospinous ligament fixation).

RESULTS

Among 610 women who underwent apical POP surgeries between May 2005 and May 2016, 24 women (3.9%) received a perioperative blood transfusion. The rate of transfusion was higher in the abdominal group (11.1%) compared with robotic (0.5%, P < 0.001) and vaginal (0.5%, P < 0.001). In a logistic regression model, abdominal route of POP surgery remained significantly associated with transfusion (odds ratio, 20.7; 95% confidence interval, 2.7-156.6). Among the 572 women who had a preoperative T&S performed, 9 (1.5%) had a positive antibody screen.

CONCLUSIONS

Blood transfusion was significantly more common in abdominal compared with robotic and vaginal apical POP surgeries. The rate of a positive antibody screen was low, suggesting that type O blood is low risk if cross-matched blood is not available. Thus, it may be reasonable to not order a preoperative T&S prior to robotic or vaginal apical POP surgery.

A novel approach to improving efficiency and cost saving in preoperative blood preparation

BACKGROUND

Preoperative ordering of blood products has been an area of optimization due to considerable variability among physicians; overpreparation can lead to extra costs and underpreparation of blood can potentially compromise patient safety.

STUDY DESIGN AND METHODS

We examined the potential cost savings of extending the storage interval of a presurgical type-and-screen sample from 7 to 14 days, thereby reducing the need for a new specimen on the day of surgery.

RESULTS

Sensitivity analysis showed annual cost savings for our institution to be an estimated $38,770 ($22,420-$73,120).

CONCLUSION

These results are even more robust when incorporating the additional potential savings from improved operating room efficiency.

Multifactorial risk index for prediction of intraoperative blood transfusion in endovascular aneurysm repair

BACKGROUND

In some institutions, the current blood ordering practice does not discriminate minimally invasive endovascular aneurysm repair (EVAR) from open procedures, with consequent increasing costs and likelihood of blood product wastage for EVARs. This limitation in practice can possibly be addressed with the development of a reliable prediction model for transfusion risk in EVAR patients. We used the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to create a model for prediction of intraoperative blood transfusion occurrence in patients undergoing EVAR. Afterward, we tested our predictive model on the Vascular Study Group of New England (VSGNE) database.

METHODS

We used the ACS NSQIP database for patients who underwent EVAR from 2011 to 2013 (N = 4709) as our derivation set for identifying a risk index for predicting intraoperative blood transfusion. We then developed a clinical risk score and validated this model using patients who underwent EVAR from 2003 to 2014 in the VSGNE database (N = 4478).

RESULTS

The transfusion rates were 8.4% and 6.1% for the ACS NSQIP (derivation set) and VSGNE (validation) databases, respectively. Hemoglobin concentration, American Society of Anesthesiologists class, age, and aneurysm diameter predicted blood transfusion in the derivation set. When it was applied on the validation set, our risk index demonstrated good discrimination in both the derivation and validation set (C statistic = 0.73 and 0.70, respectively) and calibration using the Hosmer-Lemeshow test (P = .27 and 0.31) for both data sets.

CONCLUSIONS

We developed and validated a risk index for predicting the likelihood of intraoperative blood transfusion in EVAR patients. Implementation of this index may facilitate the blood management strategies specific for EVAR.

Bleeding impacting mortality after noncardiac surgery: a protocol to establish diagnostic criteria, estimate prognostic importance, and develop and validate a prediction guide in an international prospective cohort study

INTRODUCTION

Various definitions of bleeding have been used in perioperative studies without systematic assessment of the diagnostic criteria for their independent association with outcomes important to patients. Our proposed definition of bleeding impacting mortality after noncardiac surgery (BIMS) is bleeding that is independently associated with death during or within 30 days after noncardiac surgery. We describe our analysis plan to sequentially 1) establish the diagnostic criteria for BIMS, 2) estimate the independent contribution of BIMS to 30-day mortality and 3) develop and internally validate a clinical prediction guide to estimate patient-specific risk of BIMS.

METHODS

In the Vascular Events In Noncardiac Surgery Patients Cohort Evaluation (VISION) study, we prospectively collected bleeding data for 16 079 patients aged 45 years or more who had noncardiac inpatient surgery between 2007 and 2011 at 12 centres in 8 countries across 5 continents. We will include bleeding features independently associated with 30-day mortality in the diagnostic criteria for BIMS. Candidate features will include the need for reoperation due to bleeding, the number of units of erythrocytes transfused, the lowest postoperative hemoglobin concentration, and the absolute and relative decrements in hemoglobin concentration from the preoperative value. We will then estimate the incidence of BIMS and its independent association with 30-day mortality. Last, we will construct and internally validate a clinical prediction guide for BIMS.

INTERPRETATION

This study will address an important gap in our knowledge about perioperative bleeding, with implications for the 200 million patients who undergo noncardiac surgery globally every year. Trial registration: ClinicalTrials.gov, no NCT00512109.

Are Preoperative Serologic Type and Screen Tests Necessary for Primary Total Joint Arthroplasty Patients in Specialty Surgical Hospitals?

BACKGROUND

Blood loss during total joint arthroplasty (TJA) has been a major concern requiring routine preoperative patient type and screen (T&S); however, with the implementation of blood conserving therapy, a marked decrease for perioperative transfusions has been observed. Many TJAs are now being performed in T&S mandated specialty surgical hospitals (SSHs) that lack on-site blood banks; therefore, the purpose of our study was to determine whether T&S (1) is necessary in SSH for TJA patients and (2) identifies patient risk factors associated with perioperative blood transfusion in SSH.

METHODS

A retrospective study was conducted on 1034 consecutive primary TJAs performed between 2013 and 2014 at a 12-bed SSH who all received T&S. Patients were matched (1:1) to 964 inpatient TJA patients performed at a university hospital without routine T&S. Data on surgery type, patient demographics, hemoglobin and hematocrit results, and transfusion rates were collected. Multivariate logistic regression identified perioperative transfusion risk factors.

RESULTS

Overall transfusion rates for the matched SSH (1.8% [17/964]) and university hospital populations (2.9% [28/964]) were similar (P = .13), with no emergent transfusions. SSH transfusion rates for simultaneous bilateral THA, simultaneous bilateral TKA, unilateral THA, and unilateral TKA were 21.1% (4/19), 3.1% (4/128), 2.7% (12/439), and 0.0% (0/448), respectively. Multivariate logistic regression identified unilateral THA (P ≤ .001), simultaneous bilateral TJA (P = .001), age (P = .05), and abnormal preoperative hemoglobin (P = .02) as significant transfusion risk factors at SSH.

CONCLUSION

Due to low transfusion rates and lack of emergency transfusions, we recommend routinely ordering T&S for bilateral THA but not for unilateral TJA patients, at SSHs.

Preoperative haemoglobin cut-off values for the prediction of post-operative transfusion in total knee arthroplasty

PURPOSE

The purpose of this study is to determine preoperative haemoglobin cut-off values that could accurately predict post-operative transfusion outcome in patients undergoing primary unilateral total knee arthroplasty (TKA). This will allow surgeons to provide selective preoperative type and screen to only patients at high risk of transfusion.

METHODS

A total of 1457 patients diagnosed with osteoarthritis and underwent primary unilateral TKA between January 2012 and December 2014 were retrospectively reviewed. Logistic regression analyses were applied to identify factors that could predict transfusion outcome.

RESULTS

A total of 37 patients (2.5 %) were transfused postoperatively. Univariate analysis revealed preoperative haemoglobin (p < 0.001), age (p < 0.001), preoperative haematocrit (p < 0.001), and preoperative creatinine (p < 0.001) to be significant predictors. In the multivariate analysis with patients dichotomised at 70 years of age, preoperative haemoglobin remained significant with adjusted odds ratio of 0.33. Receiver operating characteristic curve identified the preoperative haemoglobin cut-off values to be 12.4 g/dL (AUC = 0.86, sensitivity = 87.5 %, specificity = 77.2 %) and 12.1 g/dL (AUC = 0.85, sensitivity = 69.2 %, specificity = 87.1 %) for age above and below 70, respectively.

CONCLUSIONS

The authors recommend preoperative haemoglobin cut-off values of 12.4 g/dL for age above 70 and 12.1 g/dL for age below 70 to be used to predict post-operative transfusion requirements in TKA. To maximise the utilisation of blood resources, the authors recommend that only patients with haemoglobin level below the cut-off should receive routine preoperative type and screen before TKA.

LEVEL OF EVIDENCE

IV.

Interhospital Variability in Perioperative Red Blood Cell Ordering Patterns in United States Pediatric Surgical Patients

OBJECTIVE

To evaluate perioperative red blood cell (RBC) ordering and interhospital variability patterns in pediatric patients undergoing surgical interventions at US children's hospitals.

STUDY DESIGN

This is a multicenter cross-sectional study of children aged <19 years admitted to 38 pediatric tertiary care hospitals participating in the Pediatric Health Information System in 2009-2014. Only cases performed at all represented hospitals were included in the study, to limit case mix variability. Orders for blood type and crossmatch were included when done on the day before or the day of the surgical procedure. The RBC transfusions included were those given on the day of or the day after surgery. The type and crossmatch-to-transfusion ratio (TCTR) was calculated for each surgical procedure. An adjusted model for interhospital variability was created to account for variation in patient population by age, sex, race/ethnicity, payer type, and presence/number of complex chronic conditions (CCCs) per patient.

RESULTS

A total of 357 007 surgical interventions were identified across all participating hospitals. Blood type and crossmatch was performed 55 632 times, and 13 736 transfusions were provided, for a TCTR of 4:1. There was an association between increasing age and TCTR (R(2) = 0.43). Patients with multiple CCCs had lower TCTRs, with a stronger relationship (R(2) = 0.77). There was broad variability in adjusted TCTRs among hospitals (range, 2.5-25).

CONCLUSIONS

The average TCTR in US children's hospitals was double that of adult surgical data, and was associated with wide interhospital variability. Age and the presence of CCCs markedly influenced this ratio. Studies to evaluate optimal preoperative RBC ordering and standardization of practices could potentially decrease unnecessary costs and wasted blood.

Development of a risk prediction model for transfusion in carotid endarterectomy and demonstration of cost-saving potential by avoidance of "type and screen"

OBJECTIVE

Preoperative testing for carotid endarterectomy (CEA) often includes blood typing and antibody screen (T&S). In our institutional experience, however, transfusion for CEA is rare. We assessed transfusion rate and risk factors in a national clinical database to identify a cohort of patients in whom T&S can safely be avoided with the potential for substantial cost savings.

METHODS

With use of the National Surgical Quality Improvement Program database, transfusion events and timing were established for all elective CEAs in 2012-2013. Comorbidities and other characteristics were compared for patients receiving intraoperative or postoperative transfusion and those who did not. After random assignment of the total data to either a training or validation set, a prediction model for transfusion risk was created and subsequently validated.

RESULTS

Of 16,043 patients undergoing CEA in 2012-2013, 276 received at least one transfusion before discharge (1.7%); 42% of transfusions occurred on the day of surgery. Preoperative hematocrit <30% (odds ratio [OR], 57.4; 95% confidence interval [CI], 29.6-111.1), history of congestive heart failure (OR, 2.8; 95% CI, 1.1-7.1), dependent functional status (OR, 2.7; 95% CI, 1.5-5.1), coagulopathy (OR, 2.5; 95% CI, 1.7-3.6), creatinine concentration ≥1.2 mg/dL (OR, 2.3; 95% CI, 1.6-3.3), preoperative dyspnea (OR, 2.0; 95% CI, 1.4-3.1), and female gender (OR, 1.6; 95% CI, 1.1-2.3) predicted transfusion. A risk prediction model based on these data produced a C statistic of 0.85; application of this model to the validation set demonstrated a C statistic of 0.81. In the validation set, 93% of patients received a score of 6 or less, corresponding to an individual predicted transfusion risk of 5% or less. Omitting a T&S in these patients would generate a substantial annual cost saving for National Surgical Quality Improvement Program hospitals.

CONCLUSIONS

Whereas T&S are commonly performed for patients undergoing CEA, transfusion after CEA is rare and well predicted by a transfusion risk score. Avoidance of T&S in this low-risk population provides a substantial cost-saving opportunity without compromise of patient care.

Impact of Preoperative Anaemia and Blood Transfusion on Postoperative Outcomes in Gynaecological Surgery

OBJECTIVE

To evaluate the effect of preoperative anaemia and blood transfusion on 30-day postoperative morbidity and mortality in patients undergoing gynecological surgery.

STUDY DESIGN

Data were analyzed from 12,836 women undergoing operation in the American College of Surgeons National Surgical Quality Improvement Program. Outcomes measured were; 30-day postoperative mortality, composite and specific morbidities (cardiac, respiratory, central nervous system, renal, wound, sepsis, venous thrombosis, or major bleeding). Multivariate logistic regression models were performed using adjusted odds ratios (ORadj) to assess the independent effects of preoperative anaemia (hematocrit <36.0%) on outcomes, effect estimates were performed before and after adjustment for perioperative transfusion requirement.

RESULTS

The prevalence of preoperative anaemia was 23.9% (95%CI: 23.2-24.7). Adjusted for confounders by multivariate logistic regression; preoperative anaemia was independently and significantly associated with increased odds of 30-day mortality (OR: 2.40, 95%CI: 1.06-5.44) and composite morbidity (OR: 1.80, 95%CI: 1.45-2.24). This was reflected by significantly higher adjusted odds of almost all specific morbidities including; respiratory, central nervous system, renal, wound, sepsis, and venous thrombosis. Blood Transfusion increased the effect of preoperative anaemia on outcomes (61% of the effect on mortality and 16% of the composite morbidity).

CONCLUSIONS

Preoperative anaemia is associated with adverse post-operative outcomes in women undergoing gynecological surgery. This risk associated with preoperative anaemia did not appear to be corrected by use of perioperative transfusion.

Practice guidelines for perioperative blood management: an updated report by the American Society of Anesthesiologists Task Force on Perioperative Blood Management*

The American Society of Anesthesiologists Committee on Standards and Practice Parameters and the Task Force on Perioperative Blood Management presents an updated report of the Practice Guidelines for Perioperative Blood Management.

Supplemental Digital Content is available in the text.

Pediatric preoperative blood ordering: when is a type and screen or crossmatch really needed?

BACKGROUND

Unnecessary testing for and ordering of blood products adds to overall healthcare costs.

OBJECTIVES

Determine intraoperative red blood cell (RBC) product utilization for pediatric procedures and costs associated with perioperative testing and ordering.

METHODS

A retrospective chart review captured perioperative blood testing and intraoperative transfusion data for patients <19 years of age who underwent noncardiac surgery over a 13-month period at one tertiary care hospital. The main outcome measure was cost associated with testing for blood products in patients undergoing procedures that had a zero rate of transfusion.

RESULTS

The intraoperative transfusion rate for 8620 noncardiac pediatric procedures was 2.78%. Of 8380 nontransfused patients, 707 (8.4%) had type and screen, and of those, 420 (5%) were crossmatched for RBC products in preparation for surgery. The 10 surgical procedures that had the highest perioperative blood testing but no instances of transfusion were as follows: colostomy or ileostomy takedown, spinal cord untethering, tunneled catheter placement, laparoscopic Nissen fundoplication, elbow reduction and fixation, lumbar puncture, suboccipital craniectomy, hip arthrogram, percutaneous intravascular central line, and tonsillectomy and adenoidectomy. Procedures with low transfusion probability and high crossmatch testing were ventriculoperitoneal shunt revision and growing rod distraction. For all nontransfused patients, the cost of obtaining type and screen was $31,815, and the cost for crossmatch was $25,200.

CONCLUSION

Patients may undergo preoperative type and screen or crossmatch for procedures rarely associated with transfusion. Historic transfusion probability may be used to predict need for transfusion for specific surgical procedures and reduce unnecessary perioperative testing and associated costs.

Optimizing Preoperative Blood Ordering with Data Acquired from an Anesthesia Information Management System

Background:

The maximum surgical blood order schedule (MSBOS) is used to determine preoperative blood orders for specific surgical procedures. Because the list was developed in the late 1970s, many new surgical procedures have been introduced and others improved upon, making the original MSBOS obsolete. The authors describe methods to create an updated, institution-specific MSBOS to guide preoperative blood ordering.

Methods:

Blood utilization data for 53,526 patients undergoing 1,632 different surgical procedures were gathered from an anesthesia information management system. A novel algorithm based on previously defined criteria was used to create an MSBOS for each surgical specialty. The economic implications were calculated based on the number of blood orders placed, but not indicated, according to the MSBOS.

Results:

Among 27,825 surgical cases that did not require preoperative blood orders as determined by the MSBOS, 9,099 (32.7%) had a type and screen, and 2,643 (9.5%) had a crossmatch ordered. Of 4,644 cases determined to require only a type and screen, 1,509 (32.5%) had a type and crossmatch ordered. By using the MSBOS to eliminate unnecessary blood orders, the authors calculated a potential reduction in hospital charges and actual costs of $211,448 and $43,135 per year, respectively, or $8.89 and $1.81 per surgical patient, respectively.

Conclusions:

An institution-specific MSBOS can be created, using blood utilization data extracted from an anesthesia information management system along with our proposed algorithm. Using these methods to optimize the process of preoperative blood ordering can potentially improve operating room efficiency, increase patient safety, and decrease costs.

Preoperative hematocrit concentration and the risk of stroke in patients undergoing isolated coronary-artery bypass grafting

Background. Identification and management of risk factors for stroke following isolated coronary artery bypass grafting (CABG) could potentially lower the risk of such serious morbidity. Methods. We retrieved data for 30-day stroke incidence and perioperative variables for patients undergoing isolated CABG and used multivariate logistic regression to assess the adjusted effect of preoperative hematocrit concentration on stroke incidence. Results. In 2,313 patients (mean age 65.9 years, 73.6% men), 43 (1.9%, 95% CI: 1.4–2.5) developed stroke within 30 days following CABG (74.4% within 6 days). After adjustment for a priori defined potential confounders, each 1% drop in preoperative hematocrit concentration was associated with 1.07 (95% CI: 1.01–1.13) increased odds for stroke (men, OR: 1.08, 95% CI: 1.01–1.16; women, OR: 1.02, 95% CI: 0.91–1.16). The predicted probability of stroke for descending preoperative hematocrit concentration exceeded 2% for values <37% (<37% for men (adjusted OR: 2.39, 95% CI: 1.08–5.26) and <38% for women (adjusted OR: 2.52, 95% CI: 0.53–11.98), with a steeper probability increase noted in men). The association between lower preoperative hematocrit concentration and stroke was evident irrespective of intraoperative transfusion use. Conclusion. Screening and management of patients with low preoperative hematocrit concentration may alter postoperative stroke risk in patients undergoing isolated CABG.

Red blood cell transfusion during septic shock in the ICU

BACKGROUND

Transfusion of red blood cells (RBCs) remains controversial in patients with septic shock, but current practice is unknown. Our aim was to evaluate RBC transfusion practice in septic shock in the intensive care unit (ICU), and patient characteristics and outcome associated with RBC transfusion.

METHODS

Prospective cohort study of all adult patients with septic shock (n = 164) in six general ICUs during a 3-month period. Characteristics, other treatments, monitoring and outcome were compared in RBC-transfused and -non-transfused patients.

RESULTS

Ninety-nine patients (95% confidence interval 87-111) received a median 900 ml (interquartile range 490-1405) of RBC during septic shock in ICU. Among transfused patients, there were more females [49/99 (49%) vs. 22/65 (34%), P = 0.048] and surgical patients [39/99 (39%) vs. 14/65 (22%), P = 0.02] than among patients not transfused. Also, admission simplified acute physiology score II was higher and minimal haemoglobin levels (days 1-3) were lower in transfused patients compared with those not transfused. In contrast, age, markers of shock and severity organ failure assessment score on day 1 and 90-day mortality did not differ between RBC-transfused and -non-transfused patients.

CONCLUSIONS

Most patients with septic shock received RBCs during shock, and these patients had higher disease severity and lower haemoglobin levels than those not transfused. In spite of this, mortality did not differ between groups neither in the unadjusted or adjusted analyses. However, neither the design nor the sample size allows us to make inferences about treatment effects, which underlines the need for large randomised, clinical trials on transfusion in septic shock.

[Surgical risk of transfusion in a French Universitary Hospital]

INTRODUCTION

Immunohaematology examinations are usually prescribed preoperatively according to more or less standardized protocols. We wanted to assess the relevance of these protocols on the basis of factual data: an overview of the rate of transfusions carried out as part of surgery within the HCL in 2009.

STUDY DESIGN

The list of patients operated in 2009 in the HCL (IPOP by Cristalnet) has been combined with the list of patients transfused in the same time period (CTS server, Inlog). The percentage of patients transfused during the stay, and the percentage of patients transfused on the day of the intervention itself were determined for each type of surgery. The study focused on 13,571 patients affected by 44 surgeries.

PATIENTS AND METHODS

Six hundred and thirty-three patients were transfused, 45% of them the day of the intervention. The risk of needing to carry out a transfusion depends on the risk to the patient and surgery. For example, the total hip arthroplasty transfusion risk is 11.9% when it's programmed against 37.8% in emergency surgery. The transfusion risk of knee arthroscopies, osteosynthesis of wrist fracture, carpal canal surgeries and of appendectomies, thyroidectomies, herna repair surgeries are below 0.5%. The transfusion risk of colectomy is 18.1%. Thus, new recommendations for good clinical practices on the relevance of settled surgery-preoperative immunohematologic exams can be established.

CONCLUSION

The emergency degree of the transfusion must be taken into account for such recommendation. Each hospital should perform its own cartography to justify its own protocols.

Preoperative anaemia and postoperative outcomes in non-cardiac surgery: a retrospective cohort study

BACKGROUND

Preoperative anaemia is associated with adverse outcomes after cardiac surgery but outcomes after non-cardiac surgery are not well established. We aimed to assess the effect of preoperative anaemia on 30-day postoperative morbidity and mortality in patients undergoing major non-cardiac surgery.

METHODS

We analysed data for patients undergoing major non-cardiac surgery in 2008 from The American College of Surgeons' National Surgical Quality Improvement Program database (a prospective validated outcomes registry from 211 hospitals worldwide in 2008). We obtained anonymised data for 30-day mortality and morbidity (cardiac, respiratory, CNS, urinary tract, wound, sepsis, and venous thromboembolism outcomes), demographics, and preoperative and perioperative risk factors. We used multivariate logistic regression to assess the adjusted and modified (nine predefined risk factor subgroups) effect of anaemia, which was defined as mild (haematocrit concentration >29-<39% in men and >29-<36% in women) or moderate-to-severe (≤29% in men and women) on postoperative outcomes.

FINDINGS

We obtained data for 227,425 patients, of whom 69,229 (30·44%) had preoperative anaemia. After adjustment, postoperative mortality at 30 days was higher in patients with anaemia than in those without anaemia (odds ratio [OR] 1·42, 95% CI 1·31-1·54); this difference was consistent in mild anaemia (1·41, 1·30-1·53) and moderate-to-severe anaemia (1·44, 1·29-1·60). Composite postoperative morbidity at 30 days was also higher in patients with anaemia than in those without anaemia (adjusted OR 1·35, 1·30-1·40), again consistent in patients with mild anaemia (1·31, 1·26-1·36) and moderate-to-severe anaemia (1·56, 1·47-1·66). When compared with patients without anaemia or a defined risk factor, patients with anaemia and most risk factors had a higher adjusted OR for 30-day mortality and morbidity than did patients with either anaemia or the risk factor alone.

INTERPRETATION

Preoperative anaemia, even to a mild degree, is independently associated with an increased risk of 30-day morbidity and mortality in patients undergoing major non-cardiac surgery.

FUNDING

Vifor Pharma.

Perioperative blood transfusion practices in oncologic thoracic surgery: when, why, and how

INTRODUCTION

Available information on perioperative blood transfusion practices in oncologic thoracic surgery is scant and outdated. The purpose of this study was to investigate transfusion requirements in patients undergoing curative resection for lung cancer and to identify possible factors predictive of perioperative blood transfusion in our cohort of patients.

METHODS

From 1st January 2009 to 31st December 2009, 317 patients underwent anatomic pulmonary resection. Patients who received at least 1 unit of red blood cells comprised the "transfused" group. Each case in this group was matched for surgical procedure with a control subject who did not require blood transfusion and was operated on during the same year; these patients comprised the "not transfused" group.

RESULTS

A total of 75 patients (23.6%) received at least 1 unit of red blood cells during the perioperative period. Factors conditioning perioperative blood transfusion were: preoperative hemoglobin level (p < 0.0001); procedure duration (p = 0.017); body mass index (p < 0.001); induction therapies (p = 0.017); redo procedure (p = 0.021). Age, sex, histology, stage, ASA score, side, intraoperative blood loss, and fluid infusion did not affect perioperative blood transfusion practices.

CONCLUSIONS

Preoperative hemoglobin level is the major risk factor for perioperative blood transfusion practices in oncologic thoracic surgery; procedure duration, body mass index, induction therapies, and redo procedure may condition transfusional needs, although they were actually not predictive on multivariate analysis.

Risk for perioperative myocardial infarction and mortality in patients undergoing hip or knee arthroplasty: the role of anemia

BACKGROUND

Anemia is common in patients undergoing surgery. This study was designed to determine whether preoperative anemia represents an independent risk factor for 30-day mortality and nonfatal myocardial infarction (death/MI) in patients undergoing major orthopedic arthroplasty surgery.

STUDY DESIGN AND METHODS

Between January 1987 and December 2006 at the Mayo Clinic, 391 orthopedic patients experienced death/MI within 30 days of the index surgery. For each patient included in the event cohort (case), one control patient (1:1 ratio) was identified matched according to sex, age, type of joint operation (hip vs. knee vs. bilateral knee), primary operation versus revision, emergent versus elective, and date of surgery. Association of preoperative hemoglobin (Hb) with death/MI was assessed by multiple linear regression including preoperative Hb and all other characteristics and comorbid conditions found to have some evidence (p<0.10) of univariate association with death/MI.

RESULTS

After adjusting for other perioperative risk factors, anemia (Hb<12.0 g/dL for females and<13.0 g/dL for males) was not a significant independent risk factor for death/MI (odds ratio [OR], 0.81; 95% confidence interval [CI], 0.54-1.20; p=0.286), nor was Hb when treated as a continuous variable (OR, 0.98; 95% CI, 0.81-1.19 per 1.0 g/dL decrease below 13.0 g/dL; p=0.868). Cardiovascular, cerebrovascular, or pulmonary disease and history of recent malignancy were found to be the most important risk factors for death/MI.

CONCLUSION

Existing comorbidities, rather than preoperative anemia, were independently associated with major morbidity and mortality in patients undergoing major orthopedic arthroplasty.

Analysis of blood transfusion predictors in patients undergoing elective oesophagectomy for cancer

BACKGROUND

Oesophagectomy for cancers is a major operation with significant blood loss and usage. Concerns exist about the side effects of blood transfusion, cost and availability of donated blood. We are not aware of any previous study that has evaluated predictive factors for perioperative blood transfusion in patients undergoing elective oesophagectomy for cancer. This study aimed to audit the pattern of blood crossmatch and to evaluate factors predictive of transfusion requirements in oesophagectomy patients.

METHODS

Data was collected from the database of all patients who underwent oesophagectomy for cancer over a 2-year period. Clinico-pathological data collected included patients demographics, clinical factors, tumour histopathological data, preoperative and discharge haemoglobin levels, total blood loss, number of units of blood crossmatched pre-, intra- and postoperatively, number of blood units transfused, crossmatched units reused for another patient and number of blood units wasted.Clinico-pathological variables were evaluated and logistic regression analysis was performed to determine which factors were predictive of blood transfusion.

RESULTS

A total of 145 patients with a male to female ratio of 2.5:1 and median age of 68 (40-85) years were audited. The mean preoperative haemoglobin (Hb) was 13.0 g/dl. 37% of males (Hb < 13.0 g/dl) and 29% of females (Hb < 11.5 g/dl) were anaemic preoperatively. A total of 1241 blood units were crossmatched and 316 units were transfused to 71 patients. Seventy four patients (51%) did not require blood transfusion during their hospital episode. 846 blood units not used for oesophagectomy patients were reused for other patients and 79 units were wasted. The overall crossmatch to transfusion ratio was 4:1 and reuse and wastage rates were 65.2% and 6.3% respectively. The independent predictors of blood transfusion include age >70 years, Hb level <11.0 g/dl, T-stage, presence of postoperative complications and anastomotic leak.

CONCLUSION

The cohort of patients audited was over-crossmatched. The identified independent predictors of blood transfusion should be considered in preoperative blood ordering for oesophagectomy patients. This study has directly led to a reduction in the maximum surgical blood-ordering schedule for oesophagectomy to 2 units and a reaudit is underway.

The effect of national guidelines on the implementation of outpatient preoperative evaluation clinics in Dutch hospitals

BACKGROUND AND OBJECTIVES

Preoperative evaluation performed by anaesthesiologists primarily aims to estimate the risk of perioperative complications and to create opportunities to optimize the patients' condition before surgery. In this study an inventory was made of the current practice of preoperative evaluation in Dutch hospitals. It was estimated how many hospitals had implemented an outpatient preoperative evaluation clinic in 2004. Subsequently, current practice was compared with the results of a previous inventory (2000). It was also evaluated to what extent the guidelines of the Dutch Health Council and the Netherlands Society of Anaesthesiology were followed.

METHODS

The study consisted of two phases. First, a literature research was performed and pilot interviews were constructed. The interviews were conducted face-to-face with anaesthesiologists in a sample of Dutch hospitals. Based on the results, written questionnaires were constructed. In the second phase these questionnaires were sent to all general and academic hospitals in the Netherlands.

RESULTS

In 2004, 74% of the hospitals had an outpatient preoperative evaluation clinic, compared with 50% in 2000. The percentage of hospitals with an outpatient preoperative evaluation clinic available for all elective patients increased from 20% to 52%.

CONCLUSIONS

The Dutch guidelines on preoperative evaluation seem to have influenced current practice. An increase in the number of outpatient preoperative evaluation clinics was seen after the guidelines were published. The implementation of an outpatient preoperative clinic seems to warrant that anaesthesiologists are carrying out the activities prescribed by the guidelines. Most hospitals without a clinic aim to implement one in the future.

Identifying Patients at Risk of Intraoperative and Postoperative Transfusion in Isolated CABG: Toward Selective Conservation Strategies

BACKGROUND

Allogeneic blood product use during cardiac operation is often reported to exceed 40% despite published guidelines and costly blood conservation strategies. We developed a predictive model, based on eight preoperative risk factors, of allogeneic blood product transfusion rates in patients undergoing a cardiac procedure.

METHODS

All 3,046 consecutive, isolated coronary artery bypass graft (CABG) procedures at a university hospital from 1995 to 1998 were included. A logistic regression model was created to identify independent predictors of allogeneic blood product transfusion. This model was validated using a prospective patient sample.

RESULTS

Overall use of allogeneic blood products was 23% with a crude operative mortality of 2.1%. In isolated, elective, first-time CABG cases, 16.9% received allogeneic blood products. Independent predictors of blood product usage in CABG patients were preoperative hemoglobin 12.0 or less, emergent operation, renal failure, female sex, age 70 years or older, left ventricular ejection fraction 0.40 or less, redo procedure, and low body surface area. Prospective validation of this model on 2,117 consecutive isolated CABG patients demonstrated an observed-to-expected allogeneic blood product transfusion rate ratio of 1.06.

CONCLUSIONS

This internally validated logistic regression risk model is a sensitive and specific predictor of allogeneic blood product use in patients undergoing isolated CABG. Utilization of this model allows for preoperative risk stratification and may allow for more rational resource allocation of costly blood conservation strategies and blood bank resources.

Role of history and physical examination in preoperative evaluation

BACKGROUND AND OBJECTIVE

Since reports have shown that outpatient preoperative evaluation increases the quality of care and cost-effectiveness, an increasing number of patients are being evaluated purely on an outpatient basis. To improve cost-effectiveness, it would be appealing if those patients who are healthy and ready for surgery without additional testing could be easily distinguished from those who require more extensive evaluation. This paper examines whether published studies provide sufficient data to determine how detailed preoperative history taking and physical examination need to be in order to assess the health of surgical patients and to meet the objective of easy and early distinction.

METHODS

A MEDLINE search was conducted from 1991 to 2000 with respect to preoperative patient history and physical examination. Altogether, 213 articles were found, of which 29 were selected. Additionally, 38 cross-references, 7 articles on additional testing and 4 recently published papers were used.

RESULTS

It is questionable to what extent an extensive history is relevant for anaesthesia and long-term prognosis. With respect to physical examination, it seems unreasonable to diagnose valvular heart disease based on cardiac auscultation only, and it is unclear which method should be used to predict the difficulty of endotracheal intubation. The benefits of routine testing for all surgical patients before operation are extremely limited and are not advocated.

CONCLUSIONS

The amount of detail of preoperative patient history and the value of physical examination to obtain a reasonable estimate of perioperative risk remains unclear. Although not evidence based, a thorough history taking and physical examination of all patients before surgery seems important until more evidence-based guidelines become available. Diagnostic and prognostic prediction studies may provide this necessary evidence.

Validation of a clinical prediction rule to reduce preoperative type and screen procedures

BACKGROUND

We have developed a prediction rule for the occurrence of perioperative red blood cell transfusion to help to reduce the number of unnecessary preoperative type and screen procedures. We evaluated the robustness of this prediction rule in patients from another hospital.

METHODS

The rule was retrospectively applied to 1282 consecutive patients ('validation set') who underwent similar surgical procedures to the patients in the derivation study. The outcome was similarly defined as any allogeneic transfusion on the day of surgery or during the first postoperative day. The predictive value of the rule was assessed using a Receiver Operating Characteristic curve (ROC) and compared with the results of the derivation study. Subsequently, the number of correctly predicted transfusions was compared.

RESULTS

The patient characteristics did not differ between the two sets, except for the incidence of transfusion (derivation study: 18%; present study: 8%). In the validation set, the ROC area of the prediction rule was 0.78 (95% confidence intervals [CI]: 0.73-0.82), which was within the CI of the ROC area found in the derivation study (0.75; 95% CI: 0.72-0.79). In total, 35% of the type and screen procedures could be omitted (derivation study: 50%), with 13% missed transfused patients (derivation study: 20%).

CONCLUSIONS

After comparing the results of this validation study with that of the derivation study, the prediction rule was robust and may work in other clinics as well.