The Relationship between Intra-Operative Transfusions and Nadir Hematocrit on Post-Operative Outcomes after Cardiac Surgery.

Uncertainty exists regarding the optimal strategy for the management of anemia in the setting of cardiac surgery. We sought to improve our understanding of the role of intra-operative hematocrit (HCT) and transfusions on peri-operative outcomes following cardiac surgery. A total of 18,886 patients undergoing on-pump cardiac surgery were identified from a multi-institutional registry including surgical and perfusion data. Patients were divided into four groups based on their intra-operative nadir HCT (<21 or ≥21) and whether or not they received intra-operative red blood cell (+RBC or -RBC) transfusions. Outcomes were adjusted for the Society of Thoracic Surgeons predicted risk of mortality (PROM), pre-operative HCT, and medical center. Regardless of nadir HCT cohort, those who received a transfusion had higher PROM relative to patients who did not receive a transfusion. The mean PROM was significantly higher among those HCT ≥21 + RBC (5.3%) vs. HCT ≥ 21 - RBC (1.9%), p < .001. Similarly, the PROM was significantly higher among HCT <21 + RBC (5.1%) vs. those HCT <21 - RBC (3.1%), p < .001. Adjusted outcomes demonstrated an increased impact of RBC transfusions on adverse outcomes irrespective of nadir HCT including stroke (p < .001), renal failure (p < .001), prolonged ventilation (p < .001), and mortality (p < .001). This study demonstrates that transfusions have a more profound effect on post-operative cardiac surgery outcomes than anemia.

Raised haematocrit concentration and the risk of death and vascular complications after major surgery.

BACKGROUND: Preoperative anaemia is associated with adverse postoperative outcomes. Data on raised preoperative haematocrit concentration are limited. This study aimed to evaluate the effect of raised haematocrit on 30-day postoperative mortality and vascular events in patients undergoing major surgery. METHODS: This was a cohort study using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database. Thirty-day mortality and vascular events, demographics and perioperative risk factors were obtained for adults undergoing major surgery. The adjusted effect of raised (over 0·50) compared with normal (0·41-0·50, American Medical Association reference range) preoperative haematocrit concentration on postoperative outcomes was assessed. Separate sex-specific analyses were also conducted, using haematocrit concentration thresholds commonly used in the diagnosis and management of apparent or absolute erythrocytosis. RESULTS: Some 3961 (2·0 per cent) of 197 469 patients had a raised haematocrit concentration before surgery. After adjustment, the 30-day postoperative mortality rate was higher in patients with raised haematocrit than in those without (odds ratio (OR) 2·23, 95 per cent confidence interval 1·77 to 2·80). Thirty-day rates of deep vein thrombosis (OR 1·95, 1·44 to 2·64) and pulmonary embolism (OR 1·79, 1·17 to 2·73), but not myocardial infarction or stroke, were also higher in patients with a raised haematocrit concentration. The effect on mortality was noted beyond the haematocrit thresholds of 0·48 in women and 0·52 in men; the effect estimates were considerably higher for values exceeding 0·54. Values between 0·41 and 0·45 were not associated with increased mortality risk. Similar observations were noted for venous thrombosis, although with apparent sex differences. CONCLUSION: A raised haematocrit concentration was associated with an increased risk of 30-day mortality and venous thrombosis following major surgery.

Potentially modifiable predictors of mortality in patients treated with long-term oxygen therapy.

INTRODUCTION: Anemia is considered a systemic manifestation of Chronic Obstructive Pulmonary Disease (COPD); however, few studies have described its influence on chronic respiratory failure (CRF) prognosis. We aimed to test the hypotheses that anemia negatively influences survival and also to identify the cut-off points of hematocrit (Htc) and hemoglobin (Hb) associated with higher mortality in CRF patients using long-term oxygen therapy (LTOT). METHODS: One-hundred forty two patients with CRF in use of LTOT were evaluated at baseline and followed for three years or until death. Baseline assessment included identification, diagnosis, body composition, dyspnea, health status (HS), spirometry, arterial blood gases, Hb and Htc. Univariate and Cox proportional hazard models were used to evaluate predictors of mortality. We performed ROC curve to identify the best cut-off point of the variables related to survival to construct the Kaplan-Meier curves. RESULTS: Eight-three patients (58%) died after three years. Baseline values of Hb and Htc were significantly lower in the non-survivors group and both, Htc (HR, 0.96; 95%CI 0.91-0.99; p = 0.04), Hb (HR, 0.86; 95%CI 0.76-0.98; p = 0.02) were selected as predictors of mortality after three years. The cut-off points determined were: the value of HB is < 11 g/dl (sensitivity 95% specificity 85%), Htc ≤ 33% (sensitivity 97% specificity 89%). Other prognostic factors were: male gender, low PaCO(2) and SpO(2), higher dyspnea perception and impairment of HS. CONCLUSIONS: Our study shows that anemia is a predictor of mortality in patients with CRF under LTOT treatment. Although anemia is potentially modifiable, the effects of raising hemoglobin on mortality remain undetermined.

Association of quarterly average achieved hematocrit with mortality in dialysis patients: a time-dependent comorbidity-adjusted model.

BACKGROUND: Recent publications suggest that increased mortality is associated with high hematocrit targets in erythropoietin-stimulating agent-treated patients with chronic kidney disease. We aim to further inform the debate about optimal hematocrit targets, advancing the hypothesis that the current hematocrit target may not optimize the survival of patients with end-stage renal disease. STUDY DESIGN: Cross-sectional observational study. SETTING & PARTICIPANTS: Medicare dialysis patients from 2002 to 2004 (n = 393,967). FACTORS: Quarterly average hematocrit and erythropoietin alfa (EPO) dose. OUTCOMES: Mortality hazard ratios from time-dependent Cox proportional hazard models, adjusting for comorbidities. RESULTS: N = 2,712,197 patient-facility quarters. During the study, 100,086 deaths were identified. Percentages of patient quarters within each hematocrit category: hematocrit less than 27% (2.0%), 27% to 28.49% (1.7%), 28.5% to 29.9% (2.9%), 30% to 31.49% (5.2%), 31.5% to 32.99% (9.0%), 33% to 34.49% (14.9%), 34.5% to 35.99% (19.2%), 36% to 37.49% (18.0%), 37.5% to 38.99% (12.0%), 39% to 40.49% (6.4%), 40.5% to 41.99% (3.0%), and 42% or greater (3.1%). Mortality hazard ratios from the fully adjusted model: hematocrit less than 27% (3.11), 27% to 28.49% (2.60), 28.5% to 29.9% (2.14), 30% to 31.49% (1.80), 31.5% to 32.99% (1.44), 33% to 34.49% (1.17), 34.5% to 35.99% (reference), 36% to 37.49% (0.98), 37.5% to 38.99% (1.01), 39% to 40.49% (1.13), 40.5% to 41.99% (1.32), and 42% or greater (1.57). LIMITATIONS: First, potential confounding by indication related to associations between underlying illness and mortality, anemia, and EPO responsiveness. Second, Medicare claims data reflect a range of conditions and degrees of severity not easily translated into the clinical context. Third, for Medicare claims, EPO reporting is not required if EPO is not billed. Greater than 95% of "missing hematocrit" quarters are "EPO = 0" patient quarters. Interpretation of results for the missing hematocrit and EPO = 0 use categories is complicated by data source limitations. CONCLUSIONS: We show an association between mortality and low hematocrit in dialysis patients, in part reflecting the presence of comorbidities. We also show an association between increased mortality and high hematocrit. Additional interventional trials should be undertaken to better define the optimal target for anemia management in patients with end-stage renal disease, with careful prospective identification of underlying comorbidities and clinical factors contributing to high erythropoietin-stimulating agent requirement.

Factors affecting long-term survival of horses recovering from surgery of the small intestine.

REASONS FOR PERFORMING STUDY: Epiploic foramen entrapment (EFE) has been associated with a particularly poor post operative prognosis for equine colic cases, but the reasons for this are unknown. OBJECTIVES: To identify variables associated with post operative survival following surgery for small intestinal disease; develop a model describing long-term post operative survival; and identify reasons for the poor prognosis associated with EFE. METHODS: Data from 382 horses undergoing surgery were used to identify variables associated with survival. A multivariable Cox proportional hazards model for post operative survival was developed and model fit evaluated. RESULTS: The final model included the variables total plasma protein (TP) and packed cell volume (PCV) at admission, duration of surgery and the dichotomous variable relaparotomy (yes/no). Risk of death was positively associated with increasing PCV, but negatively associated with increasing TP (which decreased the probability of death). In a univariable model, EFE cases had a significantly higher death rate than other types of small intestinal disease (hazard ratio = 1.7, P = 0.035). Multivariable modelling indicated that some of the increased risk associated with EFE cases was due to lower TP values and longer duration of surgery. CONCLUSIONS: Preoperative TP is associated negatively with the risk of post operative death in horses recovering from small intestinal surgery. Other variables associated with the probability of survival are preoperative PCV, duration of surgery and relaparotomy. The increased post operative death rate of EFE cases can be explained in part by lower TP and longer surgery times of these cases. POTENTIAL RELEVANCE: Total plasma protein may be not simply a measure of hydration status in small intestinal colic cases, but an important determinant of survival. Further investigation of this relationship is warranted. Our model for post operative survival highlights the importance of preoperative TP, PCV and duration of surgery as prognostic indicators. This information should allow a more accurate post operative prognosis following small intestinal surgery.