[Preoperative evaluation of the bleeding history. Recommendations of the working group on perioperative coagulation of the Austrian Society for Anaesthesia, Resuscitation and Intensive Care]

[Preoperative evaluation of adult patients before elective, non-cardiothoracic surgery : A joint recommendation of the German Society for Anesthesiology and Intensive Care Medicine, the German Society for Surgery and the German Society for Internal Medicine]

The 70 recommendations summarize the current status of preoperative risk evaluation of adult patients prior to elective non-cardiothoracic surgery. Based on the joint publications of the German scientific societies for anesthesiology and intensive care medicine (DGAI), surgery (DGCH), and internal medicine (DGIM), which were first published in 2010 and updated in 2017, as well as the European guideline on preoperative cardiac risk evaluation published in 2022, a comprehensive re-evaluation of the recommendation takes place, taking into account new findings, the current literature, and current guidelines of international professional societies. The revised multidisciplinary recommendation is intended to facilitate a structured and common approach to the preoperative evaluation of patients. The aim is to ensure individualized preparation for the patient prior to surgery and thus to increase patient safety. Taking into account intervention- and patient-specific factors, which are indispensable in the preoperative risk evaluation, the perioperative risk for the patient should be minimized and safety increased. The recommendations for action are summarized under "General Principles (A)," "Advanced Diagnostics (B)," and the "Preoperative Management of Continuous Medication (C)." For the first time, a rating of the individual measures with regard to their clinical relevance has been given in the present recommendation. A joint and transparent agreement is intended to ensure a high level of patient orientation while avoiding unnecessary preliminary examinations, to shorten preoperative examination procedures, and ultimately to save costs. The joint recommendation of DGAI, DGCH and DGIM reflects the current state of knowledge as well as the opinion of experts. The recommendation does not replace the individualized decision between patient and physician about the best preoperative strategy and treatment.

[Obstetric Anesthesia]

Patient safety and reduction of possible complications are the top priorities for anesthesiologists in everyday clinical practice. Thus, interdisciplinary early assessment and optimization of patient specific medical conditions and risk factors are crucial. In obstetrics, regional anesthesia and general anesthesia are routinely being performed. To ensure maternal and fetal safety, knowledge regarding physiological changes during pregnancy is highly important. Regional anesthesia, particularly epidural analgesia, has its main field of application in the context of natural birth in the delivery room. Spinal anesthesia, as well as epidural and combined spinal-epidural anesthesia (CSE) are widely used for caesarean section. In this context, special attention should be paid to possible bleeding disorders. The combination of risk stratification and strategies to improve the patient's preoperative medical status is capable to reduce maternal and fetal complications.

[Coagulation diagnostics in the clinical routine-Part 1 : Evaluation of the risk of bleeding before surgery, interventions and diagnostics in bleeding diathesis]

This article on coagulation diagnostics is published in two parts covering five common clinical scenarios for coagulation diagnostics. Part 1 deals with the diagnostics prior to invasive interventions and coagulation diagnostics to clarify a tendency to bleeding. The global parameters Quick and activated partial thromboplastin time are established for monitoring certain anticoagulants; however, they are not predictive with respect to the risk of bleeding prior to elective invasive interventions. In this context, disorders of primary hemostasis are frequent, which are insufficiently detected by the global parameters. Most clinical bleeding tendencies are due to acquired causes. These include anticoagulants and diseases which can be accompanied by tendency to bleeding. For coagulation tests preanalytical issues are essential in order to avoid false results. The interpretation should always be made in the context of the current physiological state.

Risk Factors for Severe Bleeding Complications in Glaucoma Surgery and the Role of Antiplatelet or Anticoagulant Agents

Purpose

To evaluate the influences and risk factors for severe bleeding complications during glaucoma surgery, and to investigate the role of antiplatelet (AP) and anticoagulant (AC) agents.

Methods

This prospective study enrolled patients undergoing trabeculectomy, trabeculotomy (with Trabectome® or Kahook Dual Blade®), viscocanaloplasty and Ahmed or Baerveldt implants. Bleeding severity was graded on an ordinal scale ranging from 0 to 5. Immediately after surgery and one day later, the incidence and severity of bleeding events was documented on a standardized form. A grade ≥3 was defined as severe bleeding. The influence of known systemic disorders, the type of anesthesia, surgical procedure, intraoperative blood pressure, and the use of or change in AP or AC agents on intraoperative bleeding were analyzed.

Results

Data from 89 eyes undergoing glaucoma procedures were included (age 71.3y ± 10.5). We observed severe intraoperative bleeding in 8 eyes (9%) and found that concomitant diseases such as the history of a deep vein thrombosis or peripheral arterial occlusive disease, and the type of surgical procedure (trabeculectomy and viscocanaloplasty) were significantly associated with severe bleeding events. By contrast, the use of AP/ AC agents had no significant influence on severe intraoperative bleeding events.

Conclusion

According to the results of our study cohort, glaucoma procedures entailing scleral manipulations (trabeculectomy and viscocanaloplasty) and concomitant diseases such as the history of a deep vein thrombosis or peripheral arterial occlusive disease influence the risk of severe intraoperative bleeding events, we detected no increased risk related to concomitant antiplatelet and/ or anticoagulant medication use.

[Operation preparation in trauma surgery]

The success of a surgical procedure is significantly influenced by several critical factors. The safety of the patient is the primary goal. To this end, the term surgical preparation covers a number of procedures aiming to ensure the safety for the patient and a successful surgical intervention: verifying the indications, planning the intervention, identification of potential harmful factors, risks and countermeasures, patient education and documentation. Trauma surgery poses a particular challenge to preoperative preparation, especially due to urgent surgical interventions. Here, a standardized and evidence-based preoperative evaluation ensures a successful treatment of the patient.

Risk Factors for Severe Bleeding Complications in Vitreoretinal Surgery and the Role of Antiplatelet or Anticoagulant Agents

PURPOSE

To evaluate the influences and risk factors for severe bleeding complications during vitreoretinal surgery and to investigate the role of antiplatelet and anticoagulant agents.

DESIGN

Prospective trial.

PARTICIPANTS

Patients undergoing vitreoretinal surgery.

METHODS

The procedures included were pars plana vitrectomy and scleral buckling. We developed a uniform classification to grade the bleeding severity. Bleeding was graded on an ordinal scale ranging from 0 to 5. Immediately after surgery and 1 day later, the incidence and the severity of bleeding events was documented on a standardized form. A grade of 3 or more was defined as severe bleeding. Furthermore, the influence of known systemic disorders before surgery, the type of anesthesia, type of surgical procedure, intraoperative blood pressure, and the use or change of antiplatelet or anticoagulant agents on intraoperative bleeding was analyzed.

MAIN OUTCOME MEASURES

Incidence and risk factors for severe intraoperative bleeding events.

RESULTS

Data from 374 eyes undergoing vitreoretinal procedures were included in our study (mean age, 67.6 ± 12.9 years). A severe intraoperative bleeding event was observed in 15 eyes (4%). We found that concomitant diseases such as diabetes mellitus and carotid artery stenosis, the presence of diabetic retinopathy, younger age, and scleral buckling combined with a transscleral puncture were associated significantly with severe bleeding events. By contrast, use of antiplatelet or anticoagulant agents, or both, had no significant influence on severe intraoperative bleeding events.

CONCLUSIONS

Although external manipulations during buckling surgery (e.g., drainage of subretinal fluid) and concomitant diseases such as diabetes mellitus and carotid artery stenosis influences the risk of severe intraoperative bleeding events, we did not detect an increased risk related to coexisting antiplatelet or anticoagulant medication use, or both.

Caudal epidural blocks in paediatric patients: a review and practical considerations

Caudal epidural blockade in children is one of the most widely administered techniques of regional anaesthesia. Recent clinical studies have answered major pharmacodynamic and pharmacokinetic questions, thus providing the scientific background for safe and effective blocks in daily clinical practice and demonstrating that patient selection can be expanded to range from extreme preterm births up to 50 kg of body weight. This narrative review discusses the main findings in the current literature with regard to patient selection (sub-umbilical vs mid-abdominal indications, contraindications, low-risk patients with spinal anomalies); anatomical considerations (access problems, age and body positioning, palpation for needle insertion); technical considerations (verification of needle position by ultrasound vs landmarks vs 'whoosh' or 'swoosh' testing); training and equipment requirements (learning curve, needle types, risk of tissue spreading); complications and safety (paediatric regional anaesthesia, caudal blocks); local anaesthetics (bupivacaine vs ropivacaine, risk of toxicity in children, management of toxic events); adjuvant drugs (clonidine, dexmedetomidine, opioids, ketamine); volume dosing (dermatomal reach, cranial rebound); caudally accessed lumbar or thoracic anaesthesia (contamination risk, verifying catheter placement); and postoperative pain. Caudal blocks are an efficient way to offer perioperative analgesia for painful sub-umbilical interventions. Performed on sedated children, they enable not only early ambulation, but also periprocedural haemodynamic stability and spontaneous breathing in patient groups at maximum risk of a difficult airway. These are important advantages over general anaesthesia, notably in preterm babies and in children with cardiopulmonary co-morbidities. Compared with other techniques of regional anaesthesia, a case for caudal blocks can still be made.

Experimental effect of different dilutions of blood with human plasma protein fraction and large dose factor one on blood coagulation and chemistry in vitro

Background and Aims:

Human plasma protein fraction 5% (PPF5%) is an albumin-based colloid used to expand the plasma volume during volume deficiency. The current basic medical experimental study assessed in vitro coagulation of PPF5% solution and its effects on blood coagulation and chemistry.

Methods:

The study involved 20 volunteers, and each volunteer donated 20–50 ml of fresh blood. Three dilutions of blood with PPF5% dilutions were prepared (30, 50, and 70%). The fibrinogen dose required to correct coagulation in the 50% diluted samples was assessed (two doses used). The thromboelastogram (TEG) measured the haemostatic parameters (fibrinogen level, initiation of coagulation [R time], kinetics [K], acceleration of coagulation [α angle], maximum amplitude [MA] and coagulation index [CI]), and the ABL gas analyser measured the blood chemistry changes.

Results:

All dilutions showed significant TEG and blood chemistry changes when compared to controls. The two doses of fibrinogen corrected the clot formation speed with no significant difference in speed between the two doses. Acidosis measured by the strong ion gap (SID) and pH were significant for all dilutions when compared with the baseline. The 30% dilution remained within the lower normal acceptable value while 50% dilution was beyond the critical normal values.

Conclusion:

In vitro PPF5% to replace blood loss up to 50% dilution did not have significant coagulation and blood chemistry effects while coagulopathy should be expected in extreme dilutions (70%). Fibrinogen in a dose equivalent to 4 gm/70 kg adult improved clot strength at 50% dilution.

The relevance of the coagulation screen before surgery

Coagulation testing has long been part of the routine assessment of the preoperative patient, with the aim of identifying those with a bleeding disorder who might suffer significant perioperative bleeding. Some of the issues surrounding this involve the low prevalence of bleeding disorders in the general population, and the implications of further testing for both the patient and the health-care system. Studies suggest that this practice is not evidence based and is considered to be outdated. Most guidelines now advise against routine coagulation screens before surgery, and instead recommend taking a thorough personal and family history of bleeding in order to determine the need for further investigations. This review analyses current evidence on this topic and provides a comprehensive view of the relevance of preoperative coagulation testing.

[CAVE - A checklist system for preoperative risk evaluation : Guideline-conform cardiopulmonary diagnostics before general and visceral surgical interventions]

BACKGROUND

Preoperative evaluation of patient risk is an essential component of patient preparation before surgery. Guidelines provide evidence-based algorithms for preoperative assessment of cardiac risk; however, even experienced physicians correctly apply evidence-based algorithms in only 50% of all cases or less.

OBJECTIVE

A checklist system for guideline-based cardiopulmonary risk evaluation in adult patients undergoing abdominal or visceral surgery (CAVE checklists) was created to assist in preoperative cardiopulmonary risk assessment and increase correct application of evidence-based algorithms before elective visceral surgery.

MATERIAL UND METHODS

International guidelines were transformed into a checklist system. These checklists were than evaluated in a department of general and visceral surgery. The main goal was to determine whether preoperative examinations, such as electrocardiograph (ECG), chest-x-ray, spirometry and advanced assessment by a cardiologist, are performed according to evidence-based guidelines. The frequency of recommended as well as unnecessary and missed examinations was assessed.

RESULTS

In this study 541 patients with a median age of 64.5 years (interquartile range: 52-73 years) were examined using the checklist system. Of the patients 90.4% underwent ECG and 98.5% chest-X-ray as recommended in the guidelines. Spirometry was not recommended in any patient and not performed in any case. Advanced assessment by a cardiologist was performed in 45.5% of cases as recommended in the guidelines. When guidelines did not recommend ECG, x‑ray, spirometry or advanced cardiac assessment, 69.4%, 99.6%, 99.3% and 99.8% of patients, respectively, actually did not receive these examinations. Only 2.8% of all patients did not receive an examination that was recommended by the guidelines: 1.5% ECG, 0.2% x‑ray and 1.1% advanced cardiological assessment. None of these patients suffered from postoperative cardiopulmonary complications.

CONCLUSION

These simple checklists are easy to use and provide a higher degree of evidence-based preoperative cardiopulmonary risk evaluation than previously reported in the literature. Adaptation of the checklists to changing guidelines is easy to perform. Whether the application of these checklists will result in a reduction of morbidity and costs have to be determined in further clinical trials.

[Anesthesiological care of trauma patients in orthogeriatric co-management]

Elderly patients increasingly need to undergo surgery under anesthesia, especially following trauma. A timely interdisciplinary approach to the perioperative management of these patients is decisive for the long-term outcome. Orthogeriatric co-management, which includes geriatricians and anesthesiologists from an early stage, is of great benefit for geriatric patients. Patient age, comorbidities and self-sufficiency in activities of daily life are decisive for an anesthesiological assessment of the state of health and preoperative risk stratification. If necessary additional investigations, such as echocardiography must be carried out, in order to guarantee optimal perioperative anesthesiological management. Certain medical factors can delay the initiation of anesthesia and it is absolutely necessary that these are taken into consideration for surgical management. Not every form of anesthesia is equally suitable for every geriatric patient.

[Anesthesiological care in orthogeriatric co-management. Perioperative treatment of geriatric trauma patients]

Elderly patients increasingly need to undergo surgery under anesthesia, especially following trauma. A timely interdisciplinary approach to the perioperative management of these patients is decisive for the long-term outcome. Orthogeriatric co-management, which includes geriatricians and anesthesiologists from an early stage, is of great benefit for geriatric patients. Patient age, comorbidities and self-sufficiency in activities of daily life are decisive for an anesthesiological assessment of the state of health and preoperative risk stratification. If necessary additional investigations, such as echocardiography must be carried out, in order to guarantee optimal perioperative anesthesiological management. Certain medical factors can delay the initiation of anesthesia and it is absolutely necessary that these are taken into consideration for surgical management. Not every form of anesthesia is equally suitable for every geriatric patient.

[Haemostatic disorders in children]

Haemorrhagic and thrombotic events occur in both children and adults. The underlying causes are congenital or acquired disorders. In contrast to haemorrhagic disorders, inherited thrombotic disorders nearly exclusively in association with additional external risk factors lead to thrombotic events predominantly during the newborn period and adolescence. It is necessary to be aware of age-specific properties of coagulation in order to correctly interpret clinical and laboratory findings and to provide optimal care for children with haemorrhagic and thrombotic complications.

Hemostatic management of patients undergoing ear-nose-throat surgery

Perioperative hemostatic management is increasingly important in the field of otolaryngology. This review summarizes the key elements of perioperative risk stratification, thromboprophylaxis and therapies for bridging of antithrombotic treatment. It gives practical advice based on the current literature with focus on patients undergoing ENT surgery.

S3 guidelines for the management of anticoagulation in cutaneous surgery

BACKGROUND

An increasing number of patients are being treated with anticoagulants and platelet inhibitors. Whenever surgical procedures of the skin are required, questions arise regarding the perioperative management of anticoagulation.

METHODS

Development of S3 guidelines following the requirements of the Association of Scientific Medical Societies, systematic literature search and analysis, use of GRADE methodology, structured consensus conference using a nominal group process.

RESULTS

During cutaneous surgery, treatment with acetylsalicylic acid (ASA) should be continued if medically necessary. In procedures with a higher risk of bleeding and a positive bleeding history, INR should be determined preoperatively. Surgical procedures of the skin with a higher risk of bleeding should not be performed if the INR is above therapeutic range. Bridging from vitamin K antagonists (VKA) to heparin should not be performed just because of the surgery of the skin. As to direct-acting oral anticoagulants, the last dose should be taken 24 h preoperatively.

CONCLUSIONS

The recommendations issued by the German guidelines group are mostly in line with recommendations provided by other guidelines. The American ìChest-Guidelineì recommends continuing VKAs and acetylsalicylic acid during minor dermatologic procedures. In their guidelines, the German College of General Practitioners and Family Physicians considers an INR of 2 to be adequate in surgical procedures on the skin.

Risk of complications due to anticoagulation during dermatosurgical procedures: a systematic review and meta-analysis

Background Management of anticoagulation and anti-platelet drugs during cutaneous surgery is still a challenge for many dermatologists and standards of care with respect to stopping, continuing or bridging vary widely. Methods We performed a systematic review (Medline, Cochrane Library, until August 27th, 2013) of studies assessing the risk of complications due to anticoagulation during cutaneous surgery. Primary outcomes were mild-moderate and severe postsurgical bleeding. The secondary outcomes were excessive and uncontrollable intraoperative bleeding and other postsurgical complications as wound dehiscence, erythema, wound infection. Results 1.287 publications were identified and 10 studies were included into the review. The frequencies of bleeding in the control groups in general were low (about 1%). In patients on aspirin, increased risks were seen neither with respect to mild-moderate postoperative bleeding (RR 1.1, CI 0.5-2.3), nor with respect to severe bleeding (RR 0.9, CI 0.2-4.6). The studies with patients on warfarin showed a risk for mild-moderate bleeding that was three times as high as in controls (RR 3.2, CI 1.4-7.1) and for severe bleeding that was 15 times higher (RR 14.8, CI 2.7-80.4). In general the study sizes were small and the methodological quality low. Conclusion The risk of bleeding due to a medication with aspirin seems to be negligible. With warfarin, the risk is increased; an exact estimate of the risk increase is difficult to give, because of the lack of sufficient high quality studies. A two-fold increase appears likely, the 15-fold increase is most likely due to statistical reasons arising from the rareness of the event in the small number of included patients. Stopping, bridging or continuing a medication should always be an individual decision. In accordance with guidelines from internal medicine for most patients it will be recommendable to continue with the medication.

Preoperative risk assessment--from routine tests to individualized investigation

BACKGROUND

Risk assessment in adults who are about to undergo elective surgery (other than cardiac and thoracic procedures) involves history-taking, physical examination, and ancillary studies performed for individual indications. Further testing beyond the history and physical examination is often of low predictive value for perioperative complications.

METHOD

This review is based on pertinent articles that were retrieved by a selective search in the Medline and Cochrane Library databases and on the consensus-derived recommendations of the German specialty societies.

RESULTS

The history and physical examination remain the central components of preoperative risk assessment. Advanced age is not, in itself, a reason for ancillary testing. Laboratory testing should be performed only if relevant organ disease is known or suspected, or to assess the potential side effects of pharmacotherapy. Electrocardiography as a screening test seems to add little relevant information, even in patients with stable heart disease. A chest X-ray should be obtained only if a disease is suspected whose detection would have clinical consequences in the perioperative period.

CONCLUSION

In preoperative risk assessment, the history and physical examination are the strongest predictors of perioperative complications. Ancillary tests are indicated on an individual basis if the history and physical examination reveal that significant disease may be present.

Perioperative management issues of direct oral anticoagulants

The treatment repertoire of oral anticoagulation has changed dramatically over the past few years from one class of vitamin K1 antagonists to an increasing number of direct oral anticoagulants (DOACs). Clinicians are confronted with the problem of managing patients on novel agents in the critical setting before, during, and after surgery, where the risk of bleeding and thrombosis are increased simultaneously. Randomized clinical data are insufficient to date, but clinical exposure enlarges the body of experience. The following review considers perioperative management issues in various categories, including minor elective surgery, major elective surgery, and acute surgery. This review is a credo to personalized medicine where the patient's underlying thromboembolic risk status, the potential bleeding risk, or actual hemorrhagic manifestation determine the selection of multi-modal targeted management strategies.

[Basic algorithm for Point-of-Care based hemotherapy: perioperative treatment of coagulopathic patients]

During perioperative treatment of coagulopathic patients the so-called Point-of-Care (POC) analyses enable more rapidly available and more comprehensive hemostatic analyses compared to routinely performed conventional coagulation testing, such as activated partial thromboplastin time (aPTT), international normalized ratio (INR), fibrinogen concentration and platelet count. In this review article a hemotherapy algorithm is presented which is based on viscoelastic and aggregometric POC measurements. The algorithm was designed double sided and consists of a general and a special part. The general part contains boxes and fields for sociodemographic data and gives general recommendations for coagulation management and therapy specifications for particular patient collectives and presents proposals for emergency reversal of anticoagulation therapy. The special part refers to basic physiological conditions for hemostasis and asks for measurement results of clot initiation, clot firmness, clot stability and platelet function analyses. Reference values were defined for each parameter and therapeutic options are presented. In cases of persistent coagulopathy despite algorithm-conform therapy, the algorithm could be run through once again. Finally, the algorithm presents therapeutic options for an ultima ratio therapy approach.

Delayed drainage versus autotransfusion drainage and routine drainage after total knee arthroplasty: a comparative study

BACKGROUND

The purpose of this research is to compare the clinical results of different drainage methods in total knee arthroplasty (TKA).

METHODS

This retrospective comparative study included 55 patients who accepted primary unilateral TKA between October 2010 and November 2012. The patients were classified according to the drainage method used: 25 patients in the autotransfusion drainage group, 12 patients in the delayed drainage group, and 18 patients in the routine drainage group. Otherwise, the same operative procedures and postoperative care were applied to all patients. The variables recorded included total amount of postoperative drainage (including intraoperative blood loss); cases of allogenic blood transfusion; body temperatures on postoperative days 1, 3, and 7; and pre- and postoperative hemoglobin level. Some other elements such as postoperative swelling, range of motion, and wound healing were also compared.

RESULTS

Patients who underwent autotransfusion were found to have an amount of drainage (799.2 ± 196.7 mL) significantly greater than that in the routine drainage group (666.1 ± 155.0 mL), which in turn was significantly greater than that in the delayed drainage group (381.7 ± 129.2 mL). The postoperative hemoglobin level in the delayed drainage group (91.5 ± 7.9 g/L) was similar to that in the autotransfusion group (92.0 ± 9.6 g/L), while that in the routine drainage group (81.3 ± 9.9 g/L) was significantly lower. The patients in the autotransfusion group were observed to have higher body temperatures than those in the other two groups. In the routine drainage group, eight cases accepted allogenic blood transfusion, and the percentage (44.4%) was significantly higher than that in the other two groups. There were no significant between-group differences in swelling, healing qualities, and range of motion.

CONCLUSIONS

Delayed postoperative drainage may reduce blood loss and the chance of allogenic blood transfusion compared with routine drainage and may also reduce the chance of postoperative fever and extra costs compared with autotransfusion.

A brief review of 50 years of perioperative thrombosis and hemostasis management

Perioperative thrombosis and hemostasis management has changed dramatically over the past 50 years. From two anticoagulants and one anti-aggregant, the number of currently available drugs has recently increased several-fold, leaving clinicians with the problem of choosing the optimal agent. Individualized preoperative assessment of bleeding risk based on bleeding history and testing limited to high-risk patients is an emerging concept. Based on the identification of risk factors for venous thromboembolism (VTE), pharmacologic and non-pharmacologic strategies for perioperative VTE prophylaxis have had a major impact on patient outcome. For patients undergoing surgery who are treated with anticoagulants and anti-aggregants, "bridging" strategies have been proposed. Bleeding management strategies have shifted focus from replacing lost blood volume to new approaches aimed at preventing blood loss, reducing the potential complications of blood loss, and preventing the transfusion of blood products. For some areas of perioperative thrombosis and hemostasis management, randomized controlled trial (RCT) data are emerging, but the database remains insufficient to date. Clearly, more RCTs need to be published for perioperative thrombosis and hemostasis management to become an evidence-based approach.

On the value of routine prothrombin time screening in elective neurosurgical procedures

Object

The authors performed a study to evaluate whether preoperative assessment of prothrombin time (PT) is mandatory in patients undergoing routinely planned neurosurgical procedures.

Methods

The charts of all patients admitted to general wards of the authors' department for routinely planned surgery (excluding trauma and ICU patients) between 2006 and 2010 were retrospectively reviewed. The authors assessed preoperative PT and the clinical courses of all patients, with special consideration for patients receiving coagulation factor substitution. All cases involving hemorrhagic complications were analyzed in detail with regard to pre- and postoperative PT abnormalities. Prothrombin time was expressed as the international normalized ratio, and values greater than 1.28 were regarded as elevated.

Results

Clinical courses and PT values of 4310 patients were reviewed. Of these, 33 patients (0.7%) suffered hemorrhagic complications requiring repeat surgery. Thirty-one patients (94%) had a normal PT before the initial operation, while 2 patients had slightly elevated PT values of 1.33 and 1.65, which were anticipated based on the patient's history. In the latter 2 cases, surgery was performed without prior correction of PT. Preoperatively, PT was elevated in 78 patients (1.8%). In 73 (93.6%) of the 78 patients, the PT elevation was expected and explained by each patient's medical history. In only 5 (0.1%) of 4310 patients did we find an unexpected PT elevation (mean 1.53, range 1.37–1.74). All 5 patients underwent surgery without complications, while 2 had received coagulation factor substitution preoperatively, as requested by the surgeon, because of an estimated risk of bleeding complications. None of the 5 patients received coagulation factor substitution postoperatively, and later detailed laboratory studies ruled out single coagulation factor deficiencies. There was no statistically significant association between preoperatively elevated PT levels and the occurrence of hemorrhagic complications (p = 0.12). Before the second procedure but not before the initial operation, 4 (12%) of the 33 patients had elevated PT.

Conclusions

The findings suggest that the value of preoperative PT testing is limited in patients in whom a normal history can be ascertained. Close postoperative PT control is necessary in every neurosurgical patient, and better tests need to be developed to identify patients who are prone to hemorrhagic complications.

Monitoring of unfractionated heparin with rotational thrombelastometry using the prothrombinase-induced clotting time reagent (PiCT®)

PURPOSE

To achieve sufficient and safe anticoagulation with unfractionated heparin (UFH) a close and reliable drug monitoring is necessary. In general, the activated partial thromboplastin time (APTT) is used for this purpose. In acute phase response, however, the APTT test procedure might be unreliable e.g. with false low results in the presence of elevated factor VIII. In this so called heparin resistance, measurement of anti-Xa activity is recommended over APTT to avoid potentially harmful dose escalation. A combination of anti-Xa measurement and global hemostatic testing with ROTEM® employing the anti-Xa sensitive PiCT® reagent showed high correlation with enoxaparin levels. This test modification could also be suitable for monitoring UFH. Aim of the study was to evaluate the correlation between PiCT®-ROTEM® and levels of UFH.

METHODS

In this in-vitro study blood samples from healthy volunteers were spiked with UFH and subjected to different ROTEM® tests.

RESULTS

There was a linear correlation between UFH level and clotting time (CT) in the PiCT®-ROTEM® test with an excellent correlation coefficient of 0.92. Additional endpoints showed similar results (PiCT®-ROTEM® MaxVel r = -0.85 and PiCT®-ROTEM® t_MaxVel r = 0.88).

CONCLUSIONS

As a point-of-care applicable tool ROTEM® is immediately at hand. If further clinical studies confirm sensitivity in heparin resistance, PiCT®-ROTEM® could permit rapid UFH dose adjustments especially required in critical illness with acute phase response.

Effect of the carrier solution for hydroxyethyl starch on platelet aggregation and clot formation

BACKGROUND

Hydroxyethyl starch (HES) solutions alter blood coagulation, mainly platelet function and fibrinogen polymerization. Haemostasis can also be impaired by dilutional-hyperchloraemic acidosis induced by the HES carrier solution. We hypothesized that a saline-based tetrastarch carrier solution impairs parameters of blood coagulation more than a balanced carrier solution.

METHODS

The study was designed as a prospective, double-blinded, randomized, cross-over trial in healthy male volunteers. At intervals of at least 10 days, 13 subjects received 20 ml kg(-1) of balanced or saline-based tetrastarch over 2 h. Blood was subjected to blood gas analysis, assessment of platelet function [with multiple electrode aggregometry (MEA)], and clot formation (with rotational thrombelastometry).

RESULTS

Maximum aggregation in response to adenosine diphosphate (ADP) decreased after saline-based HES infusion, but not after balanced solution-based HES infusion. ADP-induced platelet aggregation was significantly lower after saline-based HES compared with baseline (21%; P<0.025) and compared with balanced solution-based HES (17%; P<0.025). There were no significant changes in platelet aggregation induced by thrombin receptor-activating peptide and in any parameter of rotational thrombelastometry. Chloride concentrations were significantly higher after saline-based HES compared with balanced solution-based HES.

CONCLUSIONS

The carrier solution for HES up to 20 ml kg(-1) had little impact on platelet aggregation or clot formation as assessed by MEA and rotational thrombelastometry, respectively. Further clinical studies are required to verify this finding in patients and to correlate results of whole blood aggregometry and rotational thrombelastometry with perioperative bleeding and transfusion requirements.

Heparin-induced effects of prothrombin complex concentrates in thromboelastometry

BACKGROUND

Prothrombin complex concentrates (PCC) are currently used to treat congenital or acquired coagulation factor deficiency. In case of serious bleeding caused by new oral anticoagulant agents, reversing treatment with PCC is under debate. PCC preparations mostly contain heparin to prevent thromboembolic events. In factor VIII and IX deficient plasma, Takeyama et al. observed in vitro a heparin effect at appropriate concentrations of PCCs. The aim of the present experiment was to investigate the heparin effect of four factor-PCC at clinically relevant concentrations in whole blood. In an in vitro experiment, we compared the PCC preparation used in the experiments of Takeyama with a high heparin content to a new heparin-free PCC preparation.

METHOD

After ethics committee approval and written informed consent, the citrated whole blood was obtained from ten healthy volunteers. We tested heparin-containing Prothromplex(®) and heparin-free Cofact(®) at concentrations of 0.31, 0.63, and 1.25 IU/ml. Protamine was added to another set of samples (1:1 heparin:protamine). We used the NATEM test in the rotational thromboelastometer ROTEM(®).

RESULTS

In the heparin PCC preparation, we observed a significant (p < 0.001) concentration-dependent prolongation in CT and CFT, even at the lowest concentration. MCF was also significantly reduced. The heparin effect was reversible by protamine. The heparin-free PCC did not affect the onset of coagulation. The interpretation of the alpha-angle showed no increased thrombus formation in heparin-free PCC preparation.

CONCLUSION

Our results extend the report of Takeyama et al. At clinically relevant PCC concentrations, the heparin effect was significant in thromboelastometry. The heparin content of PCCs should be considered in clinical routine.

[Principles of perioperative coagulation management]

The coagulation system is a complex network of interacting proteins and cells with extensive sensitivity, amplification and control pathways. The system represents a delicate balance between procoagulant and anticoagulant as well as profibrinolytic and antifibrinolytic activities. Clinically relevant phenotypes, e.g. bleeding and thrombosis, occur immediately when this balance is no longer in equilibrium. A correct understanding of the complex coagulation pathophysiology in the perioperative setting is essential for an effective treatment. In a bleeding patient, patient's history, clinical findings, routine and advanced laboratory coagulation testing as well as point-of-care coagulation monitoring help to reliably and readily identify the underlying coagulation disorder. Modern coagulation management is proactive, individualized, balanced and follows clearly defined algorithms. Coagulopathic bleeding can be successfully controlled with specific interventions in the coagulation system.

Abnormal pre-operative tests, pathologic findings of medical history, and their predictive value for perioperative complications

BACKGROUND

Laboratory tests, electrocardiogram (ECG) and chest X-rays still serve as part of the routine assessment before elective surgery in many institutions, even though there is little evidence of their predictive value relating to perioperative complications. This study investigates the correlation of abnormal findings in pre-operative tests and pathologic findings in the medical history with perioperative complications.

METHODS

Patients scheduled for elective surgery in a secondary care hospital were included in this prospective cohort study. Abnormal pre-operative tests, significant findings from the medical history and perioperative complications were recorded. Regression analysis was performed in order to identify the strongest predictors for perioperative complications.

RESULTS

A total of 1363 (56.1% female) patients were consecutively included in this study. The percentage of abnormalities in pre-operative tests ranged from 1.6% (electrolytes) and 29.7% (echocardiography). Eighty-six (6.3%) patients had at least one perioperative complication. The most frequent complications were hypo- or hypertension in 55 cases (4.0%), followed by 20 patients (1.5%) who suffered from hemodynamically relevant cardiac dysrhythmias such as supraventricular tachycardia, ventricular tachycardia, bradycardia and ventricular extrasystoles. The binary logistic regression analysis to identify predictors of perioperative complications showed significant results for age, invasiveness of the procedure, history of renal disease or anemia and abnormal ECG.

CONCLUSION

Our results indicate that age, type of surgery and medical history are appropriate predictors of perioperative complications, whereas abnormalities in laboratory tests seem to have restricted ability in predicting adverse perioperative outcome.

[Preoperative evaluation of adult patients prior to elective, non-cardiac surgery. Joint recommendations of German Society of Anesthesiology and Intensive Care Medicine, German Society of Surgery and German Society of Internal Medicine]

Evaluation of the patient's medical history and a physical examination are the cornerstones of risk assessment prior to elective surgery and may help to optimize the patient's preoperative medical condition and to guide perioperative management. Whether the performance of additional technical tests (e.g. blood chemistry, ECG, spirometry, chest-x-ray) can contribute to a reduction of perioperative risk is often not very well known or controversial. Similarly, there is considerable uncertainty among anesthesiologists, internists and surgeons with respect to the perioperative management of the patient's long-term medication. Therefore, the German Scientific Societies of Anesthesiology and Intensive Care Medicine (DGAI), Internal Medicine (DGIM) and Surgery (DGCH) have joined to elaborate and publish recommendations on the preoperative evaluation of adult patients prior to elective, non-cardiac and non-lung resection surgery. In the first part the general principles of preoperative evaluation are described (part A). The current concepts for extended evaluation of patients with known or suspected major cardiovascular disease are presented in part B. Finally, the perioperative management of patients' long-term medication is discussed (part C). The concepts proposed in these interdisciplinary recommendations endorsed by the DGAI, DGIM and DGCH provide a common basis for a structured preoperative risk assessment and management. These recommendations aim to ensure that surgical patients undergo a rational preoperative assessment and at the same time to avoid unnecessary, costly and potentially dangerous testing. The joint recommendations reflect the current state-of-the-art knowledge as well as expert opinions because scientific-based evidence is not always available. These recommendations will be subject to regular re-evaluation and updating when new validated evidence becomes available.

Fibrinogen function after severe burn injury

BACKGROUND

Evidence regarding hypercoagulability in the first week after burn trauma is growing. This hypercoagulable state may partly be caused by increased fibrinogen levels. Rotational thrombelastometry offers a test which measures functional fibrinogen (FIBTEM(®)). To test the hypothesis that in patients with severe burn injury fibrinogen function changes over time, we simultaneously measured FIBTEM(®) and fibrinogen concentration early after burn trauma.

METHODS

After Ethics Committee approval consecutive patients with severe burn trauma admitted to the burn intensive care unit of the General Hospital of Vienna were included in the study. Blood examinations were done immediately and 12, 24 and 48 h after admission. At each time point fibrinogen level (Clauss) and 4 commercially available ROTEM(®) tests were performed.

RESULTS

20 consecutive patients were included in the study. Fibrinogen level and FIBTEM(®) MCF were within the reference range until 24 h after burn trauma but increased significantly 48 h after trauma. There was a significant correlation between FIBTEM(®) MCF and fibrinogen level (R=0.714, p<0.001).

CONCLUSION

The results of this prospective observational clinical study show that fibrinogen function changes early after burn trauma and can be visualized by ROTEM(®) with the fibrinogen-sensitive FIBTEM(®) test.

[Current coagulation diagnostics in intensive care medicine]

In the preoperative setting, a standardized questionnaire on bleeding history cannot be replaced by the Quick test or activated partial thromboplastin time (APTT) measurement. Thrombelastometry provides rapid measurement of coagulation in the intra- and postoperative settings. Besides the Quick test and APTT, thrombelastometry provides information about clot firmness and clot stability. This allows goal-directed management in coagulopathy, which results in a reduction of transfusion of blood products. Furthermore, this can lead to not only an overall reduced length of stay in the hospital, but also in the intensive care unit, thus, contributing to a significant cost reduction.

[Principles of perioperative coagulation management]

The coagulation system is a complex network of interacting proteins and cells with extensive sensitivity, amplification and control pathways. The system represents a delicate balance between procoagulant and anticoagulant as well as profibrinolytic and antifibrinolytic activities. Clinically relevant phenotypes, e.g. bleeding and thrombosis, occur immediately when this balance is no longer in equilibrium. A correct understanding of the complex coagulation pathophysiology in the perioperative setting is essential for an effective treatment. In a bleeding patient, patient's history, clinical findings, routine and advanced laboratory coagulation testing as well as point-of-care coagulation monitoring help to reliably and readily identify the underlying coagulation disorder. Modern coagulation management is proactive, individualized, balanced and follows clearly defined algorithms. Coagulopathic bleeding can be successfully controlled with specific interventions in the coagulation system.

A retrospective analysis of 157 surgical procedures performed without replacement therapy in 83 unrelated factor VII-deficient patients

BACKGROUND

 Inherited factor (F)VII deficiency is the commonest of the rare bleeding disorders, with a wide set of hemorrhagic features. Other than for the severe clinical forms (for which treatment guidelines are well defined), consistent recommendations regarding perioperative replacement management do not exist for mild and asymptomatic FVII-deficient patients.

OBJECTIVES

 The present study aimed to evaluate the influence of bleeding history, FVII procoagulant activity levels (FVII:C) and the type of surgical procedure on the management of inherited FVII-deficient patients before surgery.

PATIENTS

 One hundred and fifty-seven surgical procedures, performed without replacement therapy, in 83 unrelated FVII-deficient patients (median FVII:C=5%, range 0.6%-35%) were analyzed.

RESULTS

 The overall bleeding rate was 15.3%. We found a significant relationship between previous deep traumatic hematomas and bleeding at surgery, although relationships with previous common epistaxis, easy bruising and menorrhagia were not significant. The receiver-operating characteristic (ROC) curve analysis performed on the first 83 procedures allowed us to define a cut-off value of 7% with a sensitivity of 87% (negative predictive value: 94%). To enhance the sensitivity, and to take into account the potential variation resulting from non-standardized FVII:C measurements, we would suggest applying a threshold of 10%.

CONCLUSION

 We have proposed recommendations for the perioperative management of FVII-deficient patients based on FVII:C levels, a thorough bleeding history and the type of surgery involved. By applying these recommendations, minor procedures that risk only external or controlled hemorrhage can be performed in asymptomatic or mildly affected adults, even those with FVII:C levels below 10%.

Occurrence of coagulation factor deficiency in post-tonsillectomy hemorrhage

INTRODUCTION

Tonsillectomy is one of the most common surgical procedures in Otorhinolaryngology and approximately 500 tonsillectomies are performed annually at the University Hospital of Vienna. Substantial postoperative bleeding is observed in 1.8% of cases, which is comparable to frequencies of 2-4% reported in other studies. Currently, routine pre-surgical coagulation investigations to predict bleeding status do not include the analysis of individual coagulation factors.

MATERIAL AND METHODS

Within 2007 complete coagulation diagnostics were carried out in three patients presenting with recurrent (2-7 times) post-tonsillectomy hemorrhage but normal pre-surgical coagulation status parameters.

RESULTS

After the appearance of recurrent late bleeding, single factor diagnostic analysis revealed the causes to be factor XIIa deficiency, reduced factor XIIIa or von Willebrand disease. Recurrent late bleeding was stopped by the application of coagulation active plasma.

CONCLUSION

This study shows that, even if routine diagnostics show normal pre-surgical coagulation findings, the investigation of single factors in cases of post-surgical late bleeding may identify coagulation disorders allowing the application of tailored therapy. Including such analysis in pre-operative diagnostics could therefore significantly help to limit postoperative bleeding.