The Effects of Escalation of Respiratory Support and Prolonged Invasive Ventilation on Outcomes of Cardiac Surgical Patients: A Retrospective Cohort Study.

OBJECTIVES: The aim of this study was to determine the effects of escalation of respiratory support and prolonged postoperative invasive ventilation on patient-centered outcomes, and identify perioperative factors associated with these 2 respiratory complications. DESIGN: A retrospective cohort analysis of cardiac surgical patients admitted to the cardiothoracic intensive care unit (ICU) between August 2015 and January 2018. Escalation of respiratory support was defined as "unplanned continuous positive airway pressure," "non-invasive ventilation," or "reintubation" after surgery; prolonged invasive ventilation was defined as "invasive ventilation beyond the first 12 hours following surgery." The primary endpoint was the composite of escalation of respiratory support and prolonged ventilation. SETTING: Tertiary cardiothoracic ICU. PARTICIPANTS: A total of 2,098 patients were included and analyzed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The composite of escalation of support or prolonged ventilation occurred in 509 patients (24.3%). Patients who met the composite had higher mortality (2.9% v 0.1%; p < 0.001) and longer median [interquartile range] length of ICU (2.1 [1.0-4.9] v 0.9 [0.8-1.0] days; p < 0.0001) and hospital (10.6 [8.0-16.0] v 7.2 [6.2-10.0] days; p < 0.0001) stay. Hypoxemia and anemia on admission to ICU were the only 2 factors independently associated with the need for escalation of respiratory support or prolonged invasive ventilation. CONCLUSIONS: Escalation of respiratory support or prolonged invasive ventilation is frequently seen in cardiac surgery patients and is highly associated with increased mortality and morbidity. Hypoxemia and anemia on admission to the ICU are potentially modifiable factors associated with escalation of respiratory support or prolonged invasive ventilation.

Prediction of Patient Length of Stay on the Intensive Care Unit Following Cardiac Surgery: A Logistic Regression Analysis Based on the Cardiac Operative Mortality Risk Calculator, EuroSCORE.

OBJECTIVE: The aim of this study was to develop a statistical model based on patient parameters to predict the length of stay (LOS) in the intensive care unit (ICU) following cardiac surgery in a single center. DESIGN: Data were collected from patients admitted to the ICU following cardiac surgery over a 10-year period (2006-2016). Both the additive and logistic EuroSCORE were calculated, and logistic regression analysis was carried out to formulate a model relating the predicted LOS to the EuroSCORE. This model was used to stratify patients into short stay (less than 48 hours) or long stay (more than 48 hours). SETTING: ICU at Papworth Hospital, Cambridgeshire. PARTICIPANTS: A total of 18,377 consecutive patients who had been in ICU following cardiac surgery (coronary graft bypass surgery, valve surgery, or a combination of both). INTERVENTIONS: This was an observational study. MEASUREMENTS AND MAIN RESULTS: The authors have shown that both the additive and logistic EuroSCORE can be used to stratify cardiac surgical patients in various predicted LOS in ICU. Further adjustments can be made to increase the number of patients correctly identified as either short stay or long stay. Comparison of the model predictions to the data demonstrated a high overall accuracy of 79.77%, and receiver operating characteristic curve analysis showed the area under the curve to be 0.7296. CONCLUSION: This analysis of an extensive data set shows that patient LOS in ICU after cardiac surgery in a single center can be predicted accurately using the simple cardiac operative risk scoring tool EuroSCORE. Using such predictions has the potential to improve ICU resource management.

Patients Discharged From the Intensive Care Unit on a Dopamine Infusion-A Retrospective, Observational Study.

OBJECTIVE: To assess the safety of discharging cardiac surgical patients from the intensive care unit (ICU) to wards while the patients are still receiving a dopamine infusion. DESIGN: Retrospective, observational study. SETTING: Cardiothoracic ICU of a tertiary academic hospital in the United Kingdom. PARTICIPANTS: The study comprised all cardiac surgical patients older than 18 years and admitted between September 1, 2015 and September 16, 2016 to the ICU and subsequently discharged to a surgical ward. Patients were divided in the following 2 groups: a dopamine group with patients discharged with a dopamine infusion and a control group with patients discharged without any dopamine infusion. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The hospital mortality rate was comparable in both groups (0.7% in the dopamine group v 0.2% in the control group [p = 0.11]), despite that the median logistic EuroSCORE was significantly higher in the dopamine group (7.0 v 3.8 [p < 0.01]). The ICU readmission rate was higher in the dopamine group (6.6% v 2.4%; p < 0.01). ICU and hospital lengths of stay were longer in the dopamine group (1.7 v 0.9 days [p < 0.01] and 11.4 v 8.0 days [p < 0.01], respectively). CONCLUSIONS: Despite a higher ICU readmission rate, ICU discharge of patients on dopamine infusion was not associated with increased mortality.

Acute Pain and Analgesic Requirements After Pulmonary Endarterectomy With Deep Hypothermic Circulatory Arrest.

OBJECTIVES: To assess postoperative pain intensity and the analgesic requirements in the postoperative period in patients undergoing sternotomy for pulmonary endarterectomy involving deep hypothermic circulatory arrest. DESIGN: Retrospective cohort study. SETTING: Single-center hospital study. PARTICIPANTS: Patients 18 years and older undergoing sternotomy for cardiac surgery between August 2012 and August 2014. INTERVENTIONS: No modification to usual clinical practice. MEASUREMENTS AND MAIN RESULTS: Intraoperative opioid and steroid administration, referral to the chronic pain unit, intensive care unit pain scores, and analgesic administration in the first 48 hours after the admission to the intensive care unit were recorded. Postoperative pain was evaluated by means of a categoric verbal scale from no pain (0) to severe pain (3); this is the routine analgesic scale used in the authors' intensive care unit. A total of 200 consecutive patients undergoing pulmonary endarterectomy (PEA group) were included in the study. No patient in the PEA group received morphine during surgery. The mean (standard deviation) postoperative pain intensity score at 24 hours was 0.30 (0.54) in the PEA group. Postoperative morphine was administered in 39% of patients. No PEA patient was referred to the chronic pain unit after hospital discharge. CONCLUSION: The total analgesic requirements and pain score of patients undergoing sternotomy for pulmonary endarterectomy with deep hypothermic circulatory arrest seemed to be low.

Agreement between ACT and aPTT during extracorporeal membrane oxygenation shows intra- and inter-individual variation.

AIM: We explored the relationship between activated clotting time (ACT) and activated partial thromboplastin time (aPTT) when used to monitor anticoagulation in patients undergoing extracorporeal membrane oxygenation (ECMO) support. METHODS: Data obtained in patients undergoing ECMO support between October 2012 and August 2013 in a single centre were reviewed. Clinical data were extracted from our Clinical Information System and ECMO database. ACT and aPTT values were paired when taken from the same patient, with the ACT preceding the aPTT and the heparin infusion rate was kept constant between samples. The aPTT and ACT were normalized by dividing by the mean of their respective reference ranges and are referred to as APR and N-ACT, respectively. Bivariate analysis and Bland-Altman plots were used to assess correlation and agreement. Mixed effects regression was used to model the effects of variables, including platelet count, creatinine and urea levels, plasma free haemoglobin, white cell count and ECMO flow rate on concordance between APR and N-ACT measurements. RESULTS: The Pearson product-moment correlation coefficient in 15 patients was calculated as r=0.55. The Bland-Altman plot shows a mean difference between the APR and the N-ACT of -0.08. The 95% limits of agreement were -0.67 to 0.51. Results from mixed effects regression analysis on data from the 15 patients identified platelet count (and thrombocytopenia) and urea as significant independent predictors of concordance between APR and N-ACT. CONCLUSION: We report a moderate degree of positive correlation between APR and N-ACT. We conclude that there is poor agreement between the ACT and aPTT for the heparin concentrations in patients supported with ECMO. Our results indicate that platelet count and urea are significant independent variables affecting concordance between ACT and aPTT measurements.

An exploratory cohort study comparing prothrombin complex concentrate and fresh frozen plasma for the treatment of coagulopathy after complex cardiac surgery.

BACKGROUND: Administration of coagulation factor concentrates to treat bleeding after cardiac surgery with cardiopulmonary bypass might be a strategy for reducing allogeneic blood transfusions, particularly for patients treated with warfarin preoperatively. We performed an exploratory analysis on whether the use of prothrombin complex concentrate (PCC) is safe and effective compared with fresh frozen plasma (FFP) to treat coagulopathy after pulmonary endarterectomy surgery with deep hypothermic circulatory arrest. METHODS: Consecutive adult patients who underwent pulmonary endarterectomy surgery between January 2010 and September 2012 and received PCC or FFP to treat coagulopathy were studied. Blood loss during the first 12 hours of admission to the intensive care unit and patient outcomes were compared with propensity score adjustment. RESULTS: Three hundred fifty-one patients underwent pulmonary endarterectomy surgery, all of whom had warfarin discontinued for up to 5 days before surgery; bleeding complications requiring transfusion of blood products were observed in 108 (31%) patients. Of those, 55 received only FFP and 45 received only PCC, whereas 8 received both. Blood loss was significantly greater in the FFP group compared with the PCC group after 12 hours (median [interquartile range], 650 mL [325-1075] vs 277 mL [175-608], P = 0.008). However, there was no difference in the frequency of patients receiving a red blood cell transfusion (number [percent], 44 [80%] vs 34 [76%], P = 0.594) or in the number of units of red blood cells transfused (median [interquartile range], 2 [1-4] vs 3 [1-5] units, P = 0.181). The final propensity score included preoperative international normalized ratio, postoperative activated partial thromboplastin time, and postoperative platelet count. After inclusion of the propensity score in the regression analyses, there were no differences between patients receiving only PCC and patients receiving only FFP in the need for renal replacement therapy (odds ratio [OR] 2.39, 95% confidence interval [CI] 0.51-11.20, P = 0.27), 30-day-mortality (OR 0.32, 95% CI 0.03-3.36, P = 0.35), intracranial hemorrhage (OR 0.73, 95% CI 0.14-3.89, P = 0.71), hospital length of stay (hazard ratio 0.77, 95% CI 0.50-1.19, P = 0.24), or duration of intensive care stay (hazard ratio 0.91, 95% CI 0.59-1.40, P = 0.66). CONCLUSIONS: This retrospective analysis suggests that PCC may be an alternative to FFP in patients previously treated with warfarin who are coagulopathic after major cardiac surgery. Randomized controlled studies powered to evaluate efficacy and important postoperative outcomes for patients receiving PCC versus FFP for coagulopathic bleeding after cardiopulmonary bypass are warranted.

Hemostasis Checklist Reduces Bleeding and Blood Product Consumption After Cardiac Surgery.

BACKGROUND: Considerable mediastinal bleeding is a recognized complication after cardiac surgery and may require reexploration and blood product transfusion, both of which are associated with inferior clinical outcomes with greater morbidity and mortality. The aim of this study was to develop a hemostasis checklist, with the intention of reducing mediastinal bleeding after cardiac surgery. METHODS: A hemostasis checklist was developed with multidisciplinary collaboration. It contains 2 components: a series of surgical sites and factors affecting coagulation status. The checklist is performed at a time-out before sternal wire insertion. Analysis compared outcomes for patients undergoing cardiac surgery in the 1 year before and 2 years after implementation. RESULTS: A total of 5542 patients underwent surgery during the study. After we implemented the checklist, there was a significant reduction in the reexploration rate (3.5% versus 1.9%; P < .001) and the proportion of patients bleeding greater than 1 L in 12 hours (6.1% versus 2.8%; P < .001). There was a major reduction in consumption of blood products, saving $430,513. There was progressive improvement in the second year after implementation. Checklist implementation was also associated with reduced intensive care unit and hospital length of stay, adding to the financial benefit. CONCLUSIONS: Implementation of a simple and quickly performed hemostasis checklist has had a sustained impact over the 2 years after implementation, reducing the incidence of noteworthy mediastinal bleeding and reexploration, which has resulted in a major reduction in blood product consumption. Together, these have resulted in an associated reduction in intensive care unit and hospital length of stay, and a considerable financial savings. This highlights that perioperative bleeding is a preventable complication.

Early postoperative bleeding impacts long-term survival following first-time on-pump coronary artery bypass grafting.

BACKGROUND: Significant bleeding following cardiac surgery is a recognised complication, associated with a requirement for re-exploration and blood transfusion, both associated with increased morbidity and early mortality. The aim of this study was to examine the impact of the volume of early postoperative bleeding on long-term survival for patients undergoing coronary artery bypass grafting (CABG). METHODS: A retrospective analysis was performed of patients undergoing first-time isolated CABG at a single centre between January 2003 and April 2013, conditional from 30-day survival. RESULTS: Six thousand two hundred and sixty-five patients were analysed, with a mean Logistic EuroSCORE of 4.9%. The mean age was 67.8 years. Median follow-up was 11.5 years. The overall 10- and 15-year survival was 70.6% and 51.9% respectively. Following surgery, 4.6% (n=291) required return to theatre for re-exploration, and 43.6% (n=2,733) received at least one red cell transfusion. In multivariable analysis, the strongest correlates of mortality were age, smoking history, BMI, COPD, renal impairment, preoperative left ventricular function and preoperative haemoglobin (Hb) level. Twelve-hour blood loss was an additional predictor of inferior long-term survival. Five-year survival was 89.6% for patients with <500 mL blood loss, 86.8% for 500-1,000 mL and 83.8% for >1,000 mL. Re-exploration and receiving blood transfusion were not associated with reduced long-term survival. CONCLUSIONS: Significant 12-hour blood loss is associated with inferior long-term survival following CABG. This observation supports efforts aimed at improving intra-operative haemostasis and aggressive management of patients with early signs of bleeding.

Reduced re-exploration and blood product transfusion after the introduction of the Papworth haemostasis checklist†.

OBJECTIVES: Between 2% and 8% of patients return to the theatre for mediastinal bleeding following cardiac surgery. In the majority of patients, a surgical source of bleeding is identified. Both mediastinal bleeding and re-exploration are associated with increased morbidity and mortality and the use of blood products. The aim of this study was to develop a 'haemostasis checklist' with the intention of reducing mediastinal bleeding and re-exploration following cardiac surgery. METHODS: The Papworth haemostasis checklist was developed with a multidisciplinary collaboration. It consists of 2 components: surgical sites and coagulation status. The checklist is completed at a 'time-out' prior to sternal wire insertion. The analysis compared the outcomes of patients undergoing cardiac surgery in the 1 year before and after implementation. A propensity analysis assessed the impact of re-exploration on outcomes. RESULTS: Three thousand eight hundred and eleven patients underwent cardiac surgery during the study period. Re-exploration for bleeding was associated with inferior outcomes. Following checklist implementation, there was a significant reduction in the re-exploration rate (3.47% vs 2.08%, P = 0.01) and proportion of patients bleeding >1 l in 12 h (6.1% vs 3.49%, P < 0.001). There was a significant reduction in consumption of blood products saving £102 165 ($134 198). The checklist implementation was associated with reduced intensive care unit length of stay and hospital length of stay, adding to the financial benefit. CONCLUSIONS: The haemostasis checklist represents a simple intervention which is quick and easy to use but has had a substantial impact on clinical outcomes. We have observed a significant reduction in the mediastinal blood loss, return-to-theatre rate and consumption of blood products, which is associated with a significant clinical and financial benefit.

Delayed re-exploration for bleeding after coronary artery bypass surgery results in adverse outcomes.

OBJECTIVE: We aimed to identify the impact of re-exploration for bleeding after coronary artery bypass grafting (CABG) and the effect of time delay, re-exploration within 12h (<12h) versus 12h or later (>or=12h). METHODS: Analyses of prospective clinical data on 3220 consecutive patients who underwent CABG between 2003 and 2005 were performed. Pearson chi(2) tests, Fisher's exact tests, Student's t-tests, Mann-Whitney U tests, or univariate logistic regression analysis were used to assess the effects of pre-operative and operative characteristics on re-exploration, and the effects of re-exploration and time delay on adverse outcomes. Predictors of re-exploration and its effect on adverse outcomes were further evaluated using multiple logistic regression analysis. RESULTS: One hundred ninety-one patients (5.9%) underwent re-exploration for bleeding. Re-explored patients as a group in comparison to the non-re-explored group had increased postoperative blood loss, transfusion requirements, duration of mechanical ventilation, ICU stay, intra-aortic balloon pump (IABP) and haemofiltration support, and mortality (all p<0.001). One hundred fifty-seven (82%) of the 191 patients were re-explored <12h. The group of patients who were re-explored <12h in comparison to >or=12h group had shorter ICU stay (median 3 vs 8.5 days; p<0.001), less IABP support (22.3 vs 44.1%; p=0.009) and a lower mortality (7 vs 29.4%; p=0.001). There was no significant difference in blood loss or transfusion requirements between the two groups. The predicted EuroSCORE risks of the <12h group was 6.66% and the observed mortality was 7% (p=0.865). The observed mortality of 29.4% in the >or=12h group was significantly higher than the predicted EuroSCORE risks of 7.59% (p<0.001). CONCLUSIONS: Patients requiring re-exploration for bleeding are at higher risk of adverse outcomes and this risk is increased if time to re-exploration is prolonged for 12h or longer.

The sequence and analysis of Trypanosoma brucei chromosome II.

We report here the sequence of chromosome II from Trypanosoma brucei, the causative agent of African sleeping sickness. The 1.2-Mb pairs encode about 470 predicted genes organised in 17 directional clusters on either strand, the largest cluster of which has 92 genes lined up over a 284-kb region. An analysis of the GC skew reveals strand compositional asymmetries that coincide with the distribution of protein-coding genes, suggesting these asymmetries may be the result of transcription-coupled repair on coding versus non-coding strand. A 5-cM genetic map of the chromosome reveals recombinational 'hot' and 'cold' regions, the latter of which is predicted to include the putative centromere. One end of the chromosome consists of a 250-kb region almost exclusively composed of RHS (pseudo)genes that belong to a newly characterised multigene family containing a hot spot of insertion for retroelements. Interspersed with the RHS genes are a few copies of truncated RNA polymerase pseudogenes as well as expression site associated (pseudo)genes (ESAGs) 3 and 4, and 76 bp repeats. These features are reminiscent of a vestigial variant surface glycoprotein (VSG) gene expression site. The other end of the chromosome contains a 30-kb array of VSG genes, the majority of which are pseudogenes, suggesting that this region may be a site for modular de novo construction of VSG gene diversity during transposition/gene conversion events.

The DNA sequence of chromosome I of an African trypanosome: gene content, chromosome organisation, recombination and polymorphism.

The African trypanosome, Trypanosoma brucei, causes sleeping sickness in humans in sub-Saharan Africa. Here we report the sequence and analysis of the 1.1 Mb chromosome I, which encodes approximately 400 predicted genes organised into directional clusters, of which more than 100 are located in the largest cluster of 250 kb. A 160-kb region consists primarily of three gene families of unknown function, one of which contains a hotspot for retroelement insertion. We also identify five novel gene families. Indeed, almost 20% of predicted genes are members of families. In some cases, tandemly arrayed genes are 99-100% identical, suggesting an active process of amplification and gene conversion. One end of the chromosome consists of a putative bloodstream-form variant surface glycoprotein (VSG) gene expression site that appears truncated and degenerate. The other chromosome end carries VSG and expression site-associated genes and pseudogenes over 50 kb of subtelomeric sequence where, unusually, the telomere-proximal VSG gene is oriented away from the telomere. Our analysis includes the cataloguing of minor genetic variations between the chromosome I homologues and an estimate of crossing-over frequency during genetic exchange. Genetic polymorphisms are exceptionally rare in sequences located within and around the strand-switches between several gene clusters.

The impact of administration of tranexamic acid in reducing the use of red blood cells and other blood products in cardiac surgery.

BACKGROUND: To study the effect of administration of tranexamic acid on the use of blood and blood products, return to theatre for post-operative bleeding and the length of intensive care stay after primary cardiac surgery, data for 4191 patients, of all priorities, who underwent primary cardiac operation during the period between 30/10/00 and 21/09/04 were analysed. METHODS: Retrospective analysis of data collected prospectively during the study period. The main outcome measures were whether or not patients were transfused with red blood cells, fresh frozen plasma or any blood product, the proportion of patients returned to theatre for investigation for post-operative bleeding and length of stay in the intensive care unit. We performed univariate analysis to identify the factors influencing the outcome measures and multivariate analysis to identify the effect of administration of tranexamic acid on the outcome measures. RESULTS: Administration of tranexamic acid was an independent factor affecting the transfusion of red blood cells, fresh frozen plasma or any blood product. It was also an independent factor influencing the rate of return to theatre for exploration of bleeding. The odds of receiving a transfusion or returning to theatre for bleeding were significantly lower in patients receiving tranexamic acid. The administration of tranexamic acid also significantly decreased blood loss. We did not find any association between the administration of tranexamic acid and the length of intensive care stay. CONCLUSION: Based on the analysis of 4191 patients who underwent a primary cardiac operation, administration of tranexamic acid decreased the number of patients exposed to a transfusion or returned to theatre for bleeding in our institute.

Prolonged stay in intensive care unit is a powerful predictor of adverse outcomes after cardiac operations.

BACKGROUND: The aim of this study was to examine the impact of prolonged intensive care unit (ICU) stay on in-hospital mortality and long-term survival. METHODS: Prospectively collected data from 6,101 consecutive patients who underwent surgery between 2003 and 2007 were analyzed. Prolonged ICU stay was defined as a total duration of ICU stay of 3 days or more postoperatively, including readmissions; patients with an ICU stay less than 3 days were identified as controls. Univariate and multiple variable analyses were performed to identify risk factors associated with prolonged ICU stay. RESULTS: Of 6,101 patients, 1,139 (18.7%) patients had a prolonged ICU stay. These patients had a higher ICU mortality (10%) compared with controls (0.6%; p < 0.001). On discharge from the ICU, their hospital mortality was still 6-fold higher (1.2%) compared with controls (0.2%; p < 0.001). Finally, the patients who had prolonged ICU stays had lower survival after discharge from the ICU-89.2% and 81.2% at 1 year and 3 years, respectively, compared with 97.8% and 93.6%, respectively, for controls (p < 0.001). Multiple variable analysis revealed prolonged ICU stay to be an independent predictor of prolonged hospital stay, higher hospital mortality, and poorer long-term survival (all p < 0.001). CONCLUSIONS: Prolonged ICU stay is an important predictor of adverse immediate, short-term, and long-term outcomes after cardiac operations.

An operational research approach to identify cardiac surgery patients at risk of severe post-operative bleeding.

Severe post-operative bleeding can lead to adverse outcomes for cardiac surgery patients and is a relatively common complication of cardiac surgery. One of the most effective drugs to prevent such bleeding, aprotinin, has been withdrawn from the market due to concerns over its safety. Alternative prophylactic drugs which can be given to patients to prevent bleeding can result in significant side effects and are expensive. For this reason it is difficult to make a clinical or economic case for administering these drugs to all cardiac surgery patients, and the prevailing view is that their use should be targeted at patients considered to be at relatively high risk of post-operative bleeding. However, there is currently no objective method for identifying such patients. Over the past 7 years, a team of clinicians and researchers at Papworth Hospital has collected data concerning post-operative blood loss for each cardiac surgery patient, totalling 11,592 consecutive records. They approached a team of operational researchers (MU, ACP, BR) with extensive experience of developing clinical risk models with the aim of devising a risk stratification scheme that could potentially be used to identify a cohort of higher risk patients. Such patients could be treated with the available prophylactic drugs or recruited to studies to evaluate new interventions. This paper is intended to describe the Operational Research process adopted in the development of this scheme. A concise description of the scheme and its clinical interpretation is published elsewhere.

The Papworth Bleeding Risk Score: a stratification scheme for identifying cardiac surgery patients at risk of excessive early postoperative bleeding.

OBJECTIVE: We have developed a risk stratification score to identify cardiac surgical patients at higher risk of severe postoperative bleeding to aid a decision of whether to use a specific intervention preoperatively. METHODS: We prospectively created a database of 11592 consecutive patients, who underwent cardiac surgery with cardiopulmonary bypass. An adverse outcome was formally defined as a mean blood loss exceeding 2 ml kg(-1)h(-1) measured between arrival in the intensive care unit (ICU) and the earliest of the elapse of 3h; the start of transfusion of any one of fresh-frozen plasma, platelets or cryoprecipitate; return to theatre or death. Univariate and multivariate associations of severe postoperative bleeding with patient characteristics, clinical features and procedure details were analysed on a development set. The final risk stratification scheme was then evaluated on a test set. RESULTS: Severe postoperative bleeding was associated with urgent or emergency surgery, surgery that was not coronary artery bypass grafting or single valve surgery, presence of aortic valve disease, low body mass index and older age. A risk stratification score was constructed from the above variables to define preoperative categories that demonstrated high, medium and low risk of severe postoperative bleeding. Patients deemed to be at high, medium and low risk by our preoperative scoring had a 21% (95% confidence interval: 18-24%), 8% (7-10%) and 3% (2-4%) rate of severe postoperative bleeding, respectively, within the test set. CONCLUSION: We have developed a simple risk stratification score that can separate, preoperatively, patients into risk groups with markedly different rates of severe postoperative bleeding.

Safety and efficacy of aprotinin and tranexamic acid in pulmonary endarterectomy surgery with hypothermia: review of 200 patients.

BACKGROUND: The effectiveness and safety of aprotinin in cardiac surgery has been questioned. The study aim was to compare both the blood-sparing effect and side effects of aprotinin and tranexamic acid in patients undergoing pulmonary endarterectomy. METHODS: Data were analyzed retrospectively for 200 consecutive patients who underwent pulmonary endarterectomy between October 2006 and September 2009. Pulmonary endarterectomy was performed with deep hypothermia (20°C) in all patients. Antifibrinolytic therapy changed from aprotinin to tranexamic acid in June 2008 after the withdrawal of aprotinin in the United Kingdom. RESULTS: Mean age was 55.9 years, and 58% of subjects were male. One hundred patients were studied in each group. Postoperatively, a higher incidence of seizures in the first 48 hours was seen with tranexamic acid compared with aprotinin (11% versus 4%, p = 0.06). This difference became statistically significant when excluding patients with structural brain lesions from both groups (7 versus 0, p = 0.02). Tranexamic acid patients had significantly higher median blood loss (700 mL versus 525 mL, p = 0.01). There was no significant difference between the groups in reexploration for bleeding, renal failure requiring hemofiltration, intensive care unit stay, median total stay in hospital, or in-hospital mortality. CONCLUSIONS: In our experience of patients undergoing pulmonary endarterectomy, the tranexamic acid group had a higher median blood loss and more seizures. The trend to increased seizure frequency in the tranexamic acid group may be a direct consequence of this treatment, consistent with other recently published reports.

Does body mass index (BMI) affect cost in cardiac surgery? 'A pound (pound) for pound (lb) analysis'.

The effect of BMI on cost of intensive care unit (ICU) stay and ward stay in cardiac surgery is currently unknown. To assess these data on BMI, ICU stay and EuroSCORE were prospectively collected for 6100 patients undergoing cardiac surgery between 2000 and 2004. Patients were categorised according to BMI and comparisons were conducted, using non-parametric tests (Kruskal-Wallis and Mann-Whitney U-tests). One day in ICU was costed at pound1,300 and one ward-day pound300/day by this hospital's finance department. Despite similar median (due to a distribution skewed to a short ICU stay), a significant difference is observed between all 6 groups (Kruskal-Wallis; P<0.001) for ICU stay and ward stay. Underweight and morbidly obese patients had longer ICU stays compared with the ideal weight patients (P=0.010 and P=0.004, respectively); while overweight and obese patients had shorter ICU stays (P<0.001 and P=0.007, respectively). Underweight patients had a longer ward stay than ideal weight patients (P=0.005) but there was no difference between ideal and morbidly obese patients (P=0.789). These results demonstrate that BMI has a significant impact on ICU and ward stay with 'ideal weight' not always being ideal for patients undergoing cardiac surgery. This cost appears to be independent of EuroSCORE.

Allogenic blood transfusion does not predispose to infection after cardiac surgery.

BACKGROUND: Many retrospective studies report increased postoperative infection after allogenic blood transfusion. To investigate this phenomenon, we prospectively studied 232 patients undergoing cardiac surgery. METHODS: Patients were screened daily for evidence of culture positive infections. Wounds were examined daily and defined on the ASEPSIS score. Chest radiographs and white cell counts and differentials were recorded on days 1, 2, and 4. The use of blood products was monitored blindly and independently. Patients were grouped according to transfusion status and compared using chi2 or Fisher's test. Logistic regression analyses were performed to identify predictors of transfusion and infection. RESULTS: Of 232 patients, 116 (50%) received blood product transfusion. Patients receiving blood had lower preoperative hemoglobin, were older, with a greater proportion of urgent/emergency or revision surgery, and were higher risk. Despite this, there were no differences in the frequency of chest infection (20% versus 15%, p = 0.38), urinary infection (3.5% versus 5.3%, p = 0 0.75), wound infection (3.5% versus 8.0%, p = 0.16), or overall infection (28% versus 30%, p = 0.89) comparing the transfused versus untransfused groups. There was no evidence to suggest that administration of blood products was associated with infection (odds ratio 0.92, p = 0.77). CONCLUSIONS: The administration of blood per se did not lead to increased postoperative infection. Clinicians should reconsider withholding blood transfusion in patients solely owing to concerns of predisposition to infection.