Perioperative haemotherapy: II. Risks and complications of blood transfusion

The Use of Bone Wax in Hemostatic Control for Total Knee and Hip Arthroplasties: A Systematic Review

Background/Objectives: Blood loss can be a serious complication in patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA). Various methods are used by surgeons to achieve hemostatic control in these patients. Complications are associated with perioperative blood loss. In this systematic review, we examined the efficacy of using bone wax to control bleeding in patients undergoing THA and TKA. Methods: The PRISMA model was used to systematically identify and aggregate articles for this study. The PubMed and EMBASE databases were used to search individual studies that examined the use of bone wax in THA or TKA. After applying the search term "bone wax", 2478 articles were initially identified. After inclusion and exclusion criteria were applied, three articles were aggregated for this systematic review. Results: The use of bone wax in THA and TKA decreased blood loss in patients undergoing these operations. Postoperative blood loss following surgery was lower in the bone wax groups compared to the control groups as well. Patients in the bone wax groups also required fewer blood transfusions than those who did not receive bone wax. Conclusions: Bone wax appears to be another modality that can be used by physicians to maintain hemostatic control in THA or TKA patients. Reduced blood loss and transfusion rates in surgery can increase patient outcomes. More studies are needed to examine the efficacy of bone wax in comparison with other hemostatic tools.

Analysis of Intraoperative Variables Responsible for the Increase in Lactic Acid in Patients Undergoing Debulking Surgery

Background: Cytoreductive surgery (CRS) is a complex procedure with a high incidence of perioperative complications. Elevated lactacidaemia levels have been associated with complications and perioperative morbidity and mortality. This study aims to analyse the intraoperative variables of patients undergoing CRS and their relationship with lactacidaemia levels. Methods: This retrospective, observational study included 51 patients with peritoneal carcinomatosis who underwent CRS between 2014 and 2016 at the Abdomino-Pelvic Oncological Surgery Reference Unit (URCOAP) of the General University Hospital of Castellón (HGUCS). The main variable of interest was the level of lactic acid at the end of surgery. Intraoperative variables, including preoperative haemoglobin, duration of surgery, intraoperative bleeding, fluid therapy administered, administration of blood products, and intraoperative peritoneal cancer index (PCI), were analysed. Results: Positive correlations were found between lactic acid levels and PCI, duration of intervention, fluid therapy, intraoperative bleeding, and transfusion of blood products. Additionally, a negative correlation was observed between haemoglobin levels and lactic acid levels. Notably, the strongest correlations were found with operative PCI (ρ = 0.532; p-value < 0.001) and duration of surgery (ρ = 0.518; p-value < 0.001). Conclusions: PCI and duration of surgery are decisive variables in determining the prognosis of patients undergoing debulking surgery. This study suggests that, for each minute of surgery, lactic acid levels increase by 0.005 mmol/L, and for each unit increase in PCI, lactic acid levels increase by 0.060 mmol/L.

Hemodiafiltration-A Technique for Physiological Correction of Priming Solution in Pediatric Cardiac Surgery: An In Vitro Study

Pediatric cardiopulmonary bypass (CPB) circuit invariably requires priming with packed red blood cells (PRBCs). Metabolic composition of stored PRBCs is unphysiological and becomes worse with increasing duration of storage. It is recommended to correct these abnormalities before initiation of CPB. We tested the hypothesis that hemodiafiltration of the prime with 0.45% saline is sufficient for reducing the metabolic load and reaching a physiologic state. In an in vitro study, 100 mL of blood each from 45 units of PRBCs stored for 3-20 days were used for priming the 45 neonatal CPB circuits. Based upon the method used for removal of excess crystalloid from the prime, circuits were divided into three groups. Group 1: Direct removal through manifold line. Group 2: Ultrafiltration of prime. Group 3: Hemodiafiltration of the prime. Blood gas analyses were obtained from the PRBCs and from the prime before and after removal of crystalloid. Both direct removal of crystalloid and ultrafiltration resulted in significant reduction in biochemical and metabolic load of blood (P < 0.001). However, the final composition of the prime was far from being physiological. Hemodiafiltration resulted in improvement of metabolic parameters to near physiological range (lactate: 33.8 ± 4.44 vs. 14 ± 2.53 mg/dL, pH: 7.05 ± 0.15 vs. 7.34 ± 0.06, bicarbonates: 4.83 ± 0.59 vs. 27.6 ± 2.94 meq/L; P < 0.001). Similarly, sodium (147.76 ± 12.73 vs. 144.6 ± 5.96 meq/L) and potassium (9.6 ± 2.83 vs. 4.23 ± 0.37 meq/L) also changed significantly (P < 0.001) to near physiologic range. Hemodiafiltraion of final prime is a simple, efficients and rapid method of correcting the biochemical parameters and reducing the metabolic load of stored PRBCs towards the physiological range before initiating the CPB.

Autologous blood transfusion in trauma

Transfusion of autologous blood, recovered from the surgical field, has been widely accepted for use in elective cases with significant blood loss. The use of these techniques in the setting of exsanguinating traumatic haemorrhage has been limited, however, by a number of confounding issues. These include: (a) the potential for increased infectious complications resulting from the reinfusion of blood from a contaminated field; (b) the risk of exacerbating a consumptive coagulopathy; (c) a potential increased risk of multiple organ failure syndrome due to the infusion of cytokines and activated inflammatory mediators; (d) the practicality and logistics of this approach in the moribund patient; and (e) the cost-effectiveness of this technology. The purpose of this review is to evaluate the current literature addressing these issues and better define the role for autologous transfusion in the trauma population.

Evaluation of an improved blood-conserving POCT sampling system

OBJECTIVE

To evaluate a modified point-of-care (POCT) testing i-STAT analyzing cartridge that connects directly to the sampling port of a blood-conserving sampling line.

DESIGN AND METHODS

In an in vitro setup, blood samples were drawn from a blood-conserving sampling line connected to a miniature cardiopulmonary bypass (CPB) system. Blood collection from the sampling port was either performed with a syringe necessitating subsequent sample loading on a standard i-STAT cartridge (conventional procedure) or with a modified i-STAT sampling cartridge allowing blood flow from the sampling port directly into the cartridge (modified procedure). The loaded cartridges were subsequently inserted into the i-STAT Portable Clinical Analyzer for sample analysis. Multiple parameters such as blood gases, electrolytes, hematocrit, and glucose were measured. A series of 30 paired measurements was performed. Corresponding series of values were compared using linear regression analysis and Bland-Altman bias analysis (P < 0.05).

RESULTS

Twenty-five complete measurement series consisting of 12 parameters (pH, pCO(2), pO(2), SO(2), base excess, bicarbonate concentration, sodium, potassium, ionized calcium, hemoglobin concentration, hematocrit, glucose) were evaluated. Linear regression analysis between the two sampling methods tested demonstrated an excellent correlation for all parameters (Pearson correlation coefficients: 0.859-0.999). Bias and precision between corresponding series showed clinically acceptable performance levels for all parameters.

CONCLUSIONS

The modified i-STAT sampling cartridge allows reliable diagnostic blood sampling directly from a blood-conserving sampling line. The technique presented is also applicable to other POCT systems, thus reducing diagnostic blood loss because of the minimal amount of blood required for analysis.

Cell salvage does not minimize perioperative allogeneic blood transfusion in abdominal vascular surgery: a systematic review

PURPOSE

To determine whether the use of cell salvage reduces the proportion of patients receiving at least one unit of allogeneic packed red blood cells during the perioperative period of an elective vascular surgery.

SOURCE

We identified all relevant articles through the combined use of electronic searches of the MEDLINE and EMBASE databases, the Cochrane library as well as hand searching of all randomized clinical trials and review articles. The electronic search included articles published between 1966 and April 2001. The search included textword searches using "autotransfusion," "cell salvage," "device," or Medical Subject Headings "autologous blood transfusion" or a "randomized controlled trials" filter.

PRINCIPAL FINDINGS

Five randomized controlled trials (RCT) were identified involving cell salvage and vascular surgeries. In infra renal abdominal aortic aneurysm surgery the risk ratio (the risk of receiving at least one unit of allogeneic red cells) was 0.37 [95% confidence intervals (CI) of 0.06 to 2.36]. In elective aorto-femoral bypass surgery the risk ratio was 0.97 (95% CI of 0.66 to 1.42). The pooled risk ratio for cell salvage in vascular surgery was 0.67 (95% CI of 0.35 to 1.28).

CONCLUSION

Cell salvage, a commonly used technique to recover red cells from the operative field, has been the subject of several studies in vascular surgery. There is insufficient evidence to recommend the routine use of cell salvage in elective abdominal aortic aneurysm and aorto-femoral bypass surgeries. A large RCT would elucidate whether cell salvage is effective as a blood conservation technique.

Saturday night fever: finding and controlling the source of sepsis in critical illness

Fever is a daily concern in the intensive care unit. Although about half of all febrile cases are due to non-infectious causes, fear of sepsis frequently leads to diagnostic tests and escalation of therapy, including broadening antibiotic therapy. Using a case to illustrate this dilemma, we discuss the commonest non-infectious and infectious causes of fever, and suggests approaches to their management. Any unexplained fever in intensive care unit patients warrants investigation, which includes complete clinical assessment and blood cultures. When the source of fever is not immediately apparent, non-infectious and infectious causes should be considered. If stable, non-neutropenic patients should be monitored before further tests or empiric antibiotics are started. In an era of rapid emergence and spread of antimicrobial-resistant pathogens and intense scrutiny of resources, optimal diagnosis and management of patients with suspected infection entails much more than the escalation of antimicrobial therapy.

Debate: transfusing to normal haemoglobin levels will not improve outcome

Recent evidence suggests that critically ill patients are able to tolerate lower levels of haemoglobin than was previously believed. It is our goal to show that transfusing to a level of 100 g/l does not improve mortality and other clinically important outcomes in a critical care setting. Although many questions remain, many laboratory and clinical studies, including a recent randomized controlled trial (RCT), have established that transfusing to normal haemoglobin concentrations does not improve organ failure and mortality in the critically ill patient. In addition, a restrictive transfusion strategy will reduce exposure to allogeneic transfusions, result in more efficient use of red blood cells (RBCs), save blood overall, and decrease health care costs.

Hemoglobin solutions--not just red blood cell substitutes

OBJECTIVE

To review current knowledge about cell-free hemoglobin solutions.

DATA SOURCES

All studies involving cell-free hemoglobin were retrieved from a computerized MEDLINE search from 1980 to 1998. We also reviewed the reference lists of all available review articles and primary studies to identify references not found in the computerized search.

STUDY SELECTION

Clinical and experimental studies in which cell-free hemoglobin solutions were studied.

DATA EXTRACTION

From the selected studies, information was obtained regarding the experimental model or the study population in which cell-free hemoglobin solutions were investigated, the type of cell-free hemoglobin solution, their deleterious or beneficial effects, and their possible indications.

DATA SYNTHESIS

In many studies, hemoglobin solutions were considered as efficient resuscitative agents and good alternatives to red blood cell transfusion, because of their marked vasopressor effect coupled with their capacity to improve the microcirculation and quickly restore metabolic parameters. Nevertheless, potential problems include an increased susceptibility to infection, immunosuppression, oxidative damage, excessive pulmonary and systemic vasoconstriction, and platelet activation.

CONCLUSIONS

Hemoglobin solutions are more than mere blood substitutes. Promising effects on oxygen transport and the microcirculation need to be confirmed, and the results of continuing research are eagerly awaited.

Important role of nondiagnostic blood loss and blunted erythropoietic response in the anemia of medical intensive care patients

OBJECTIVE

To determine incidence, severity, characteristics, and causes of anemia and transfusion requirements in medical intensive care patients.

DESIGN AND SETTING

Open prospective clinical study in a 24-bed medical intensive care unit in a tertiary-care university hospital.

PATIENTS

Patients (N = 96) treated in the intensive care unit for >3 days.

INTERVENTIONS

None.

MEASUREMENTS

Parameters of erythropoiesis and red blood cell metabolism, including hemoglobin, reticulocyte counts, serum iron, transferrin, ferritin, haptoglobin, vitamin B12, folic acid, and erythropoietin concentrations were determined serially. Diagnostic blood loss and red blood cell transfusions were recorded, and the total blood loss was estimated from changes in hemoglobin concentrations and the amount of hemoglobin transfused.

MAIN RESULTS

The median hemoglobin concentration was 12.1 g/dL at admission and 11.2 g/dL at the end of the intensive care unit stay. A total of 74 patients (77%) suffered from anemia and received 257 red blood cell units, approximately half of which were given within the first 5 days. Three patients who received 19 red blood cell units were admitted with acute gastrointestinal bleeding, but in the remainder, a median total blood loss of 128 mL/d was not (n = 60) or not solely (n = 11) a result of overt bleeding. Diagnostic blood loss declined from a median of 41 mL on day 1 to <20 mL after 3 wks and contributed 17% (median) to total blood loss. Acute renal failure, fatal outcome, and simplified acute physiology score >38 on admission were associated with a 5.8-, 7.0-, and 2.8-fold increase in total blood loss. Reticulocyte counts and erythropoietin concentrations were inappropriately low for the degree of anemia, and plasma transferrin saturation was mostly <20%.

CONCLUSIONS

Anemia is frequent and results in a high requirement for red blood cell transfusions in the medical intensive care setting. A major proportion of blood loss is not caused by overt bleeding or diagnostic blood sampling but, rather, may result from various other reasons, e.g., occult gastrointestinal bleeding and renal replacement therapy. The erythropoietic response to anemia is blunted, probably as a consequence of an inappropriate increase in erythropoietin production and diminished iron availability. (Crit Care Med 1999; 27:2630-2639)

Variation in red cell transfusion practice in the intensive care unit: a multicentre cohort study

OBJECTIVES: To determine the degree of interinstitutional transfusion practice variation and reasons why red cells are administered in critically ill patients. STUDY DESIGN: Multicentre cohort study combined with a cross-sectional survey of physicians requesting red cell transfusions for patients in the cohort. STUDY POPULATION: The cohort included 5298 consecutive patients admitted to six tertiary level intensive care units in addition to administering a survey to 223 physicians requesting red cell transfusions in these units. MEASUREMENTS: Haemoglobin concentrations were collected, along with the number and reasons for red cell transfusions plus demographic, diagnostic, disease severity (APACHE II score), intensive care unit (ICU) mortality and lengths of stay in the ICU. RESULTS: Twenty five per cent of the critically ill patients in the cohort study received red cell transfusions. The overall number of transfusions per patient-day in the ICU averaged 0.95 +/- 1.39 and ranged from 0.82 +/- 1.69 to 1.08 +/- 1.27 between institutions (P < 0.001). Independent predictors of transfusion thresholds (pre-transfusion haemoglobin concentrations) included patient age, admission APACHE II score and the institution (P < 0.0001). A very significant institution effect (P < 0.0001) persisted even after multivariate adjustments for age, APACHE II score and within four diagnostic categories (cardiovascular disease, respiratory failure, major surgery and trauma) (P < 0.0001). The evaluation of transfusion practice using the bedside survey documented that 35% (202 of 576) of pre-transfusion haemoglobin concentrations were in the range of 95-105 g/l and 80% of the orders were for two packed cell units. The most frequent reasons for administering red cells were acute bleeding (35%) and the augmentation of O2 delivery (25%). CONCLUSIONS: There is significant institutional variation in critical care transfusion practice, many intensivists adhering to a 100g/l threshold, and opting to administer multiple units despite published guidelines to the contrary. There is a need for prospective studies to define optimal practice in the critically ill.

A Canadian survey of transfusion practices in critically ill patients. Transfusion Requirements in Critical Care Investigators and the Canadian Critical Care Trials Group

OBJECTIVES

To characterize the contemporary red cell transfusion practice in the critically ill and to define clinical factors that influence these practices.

DESIGN

Scenario-based national survey.

STUDY POPULATION

Canadian critical care practitioners.

MEASUREMENTS AND MAIN RESULTS

We evaluated transfusion thresholds before transfusion and the number of red cell units ordered, under the given conditions. Of 254 Canadian critical care physicians, 193 (76%) responded to the survey. The primary specialty of most respondents was internal medicine (56%). Internal medicine respondents were in practice for an average of 8.4 +/- 5.7 (SD) yrs, and worked most often in combined medical/surgical intensive care units. Baseline hemoglobin transfusion thresholds averaged from 8.3 +/- 1.0 g/dL in a scenario involving a young stable trauma victim to 9.5 +/- 1.0 g/dL for an older patient after gastrointestinal bleeding. Transfusion thresholds differed significantly (p< .0001) between all four separate scenarios. With the exception of congestive heart failure (p> .05), all clinical factors (including age, Acute Physiology and Chronic Health Evaluation II score, preoperative status, hypoxemia, shock, lactic acidosis, coronary ischemia, and chronic anemia) significantly (p< .0001) modified the transfusion thresholds. A statistically significant (p< .01) difference in baseline transfusion thresholds was noted across four major regions (with a maximum of five academic centers per region) of the country. Low physician numbers in two of the regions did not allow for further investigation of regional variations.

CONCLUSIONS

There is significant variation in critical care transfusion practice, with many intensivists adhering to a 10.0-g/dL threshold, while other physicians described a much more restrictive approach to red cell transfusion. Also, many physicians opted to administer multiple units, despite published guidelines to the contrary. Additionally, the administration of red cells was strongly influenced by a number of clinical factors, many unique to intensive care unit patients. There is a need for prospective studies to define optimal practice in the critically ill.

Intraoperative autologous blood transfusion in intracranial surgery

OBJECTIVE

The purpose of this study was to evaluate the benefits of intraoperative autotransfusion of autologous blood on the conservation of allogenic blood, including cost-effectiveness and the consequences for hemoglobin level and coagulation tests.

METHODS

The Hoemonetics Cell Saver 4 autotransfusion system (Hoemonetics Corporation, MA) was used when the estimated blood loss was equal to or more than 500 ml. A total of 472 patients undergoing intracranial surgery were included in the study.

RESULTS

Ninety patients (19%) received transfusions either with autologous blood or allogenic blood. Fifty-five patients (61%) received only autologous blood transfusions, 10 patients (11%) received both autologous and allogenic blood transfusions, and 25 patients (28%) received only allogenic blood transfusions. The amount of autologous blood transfused was 600 +/- 590 ml (range, 230-3000 ml). The amount of allogenic blood transfused was 3 +/- 3 units (range, 2-15 units). Autologous blood represented 68% of all blood products transfused. Mild abnormalities during coagulation tests occurred without clinical bleeding.

CONCLUSION

Autologous blood transfusions were demonstrated to be safe in patients undergoing intracranial surgery and to be more cost-effective than allogenic blood transfusions. Intraoperative autologous blood transfusions may be used alone in more than half of the patients requiring transfusions during intracranial surgery and decrease the amount of allogenic blood used. Improvements in the monitoring for the need of performing this technique, as well as preoperative blood donations, would decrease the amount of allogenic blood transfused.

Perioperative morbidity in maxillofacial orthopaedic surgery: a retrospective study

The data of 2049 patients, who underwent maxillofacial orthopaedic surgery, were retrospectively analysed for major intra- and immediate postoperative complications. Immediate life-threatening complications were very rare. They can in most cases be avoided by good anaesthetic and surgical techniques and adequate postoperative care. The most frequently encountered problem in maxillary surgery is excessive blood loss, whilst a compromised airway due to swelling is the most frequent complication in mandibular surgery. Good co-operation between anaesthetist and surgeon is essential to prevent major intraoperative and immediate postoperative problems.