In Nordic countries 30-day mortality rate is half that estimated with EuroSCORE II in high-risk adult patients given aprotinin and undergoing mainly complex cardiac procedures

Objectives. To describe current on- (isolated coronary arterty bypass grafting, iCABG) and off-label (non-iCABG) use of aprotinin and associated safety endpoints in adult patients undergoing high-risk cardiac surgery in Nordic countries. Design. Data come from 10 cardiac surgery centres in Finland, Norway and Sweden participating in the European Nordic aprotinin patient registry (NAPaR). Results. 486 patients were given aprotinin between 2016 and 2020. 59 patients (12.1%) underwent iCABG and 427 (87.9%) non-iCABG, including surgery for aortic dissection (16.7%) and endocarditis (36.0%). 89.9% were administered a full aprotinin dosage and 37.0% were re-sternotomies. Dual antiplatelet treatment affected 72.9% of iCABG and 7.0% of non-iCABG patients. 0.6% of patients had anaphylactic reactions associated with aprotinin. 6.4% (95 CI% 4.2%-8.6%) of patients were reoperated for bleeding. Rate of postoperative thromboembolic events, day 1 rise in creatinine >44μmol/L and new dialysis for any reason was 4.7% (95%CI 2.8%-6.6%), 16.7% (95%CI 13.4%-20.0%) and 14.0% (95%CI 10.9%-17.1%), respectively. In-hospital mortality and 30-day mortality was 4.9% (95%CI 2.8%-6.9%) and 6.3% (95%CI 3.7%-7.8%) in all patients versus mean EuroSCORE II 11.4% (95%CI 8.4%-14.0%, p < .01). 30-day mortality in patients undergoing surgery for aortic dissection and endocarditis was 6.2% (95%CI 0.9%-11.4%) and 6.3% (95%CI 2.7%-9.9%) versus mean EuroSCORE II 13.2% (95%CI 6.1%-21.0%, p = .11) and 14.5% (95%CI 12.1%-16.8%, p = .01), respectively. Conclusions. NAPaR data from Nordic countries suggest a favourable safety profile of aprotinin in adult cardiac surgery.

Albumin and Cardioprotection in On-Pump Cardiac Surgery-A Post Hoc Analysis of a Randomized Trial

OBJECTIVES

To study the quantitative potency of plasma albumin on cardioprotection in terms of creatinine kinase-myocardial band mass (CK-MBm) in on-pump cardiac surgery.

DESIGN

Post hoc analysis of a double-blinded randomized clinical trial.

SETTING

Single-center study in the Helsinki University Hospital.

PARTICIPANTS

A total of 1,386 adult on-pump cardiac surgical patients.

INTERVENTION

Administration of 4% albumin (n = 693) or Ringers acetate (n = 693) for cardiopulmonary bypass priming and volume replacement intraoperatively and postoperatively during the first 24 hours.

MEASUREMENTS AND MAIN RESULTS

Albumin concentration was measured preoperatively and intraoperatively (after protamine administration), and CK-MBm on the first postoperative morning. Multivariate linear regression analyses were measured in the whole cohort and the Ringer group. Plasma albumin concentration did not differ between the groups preoperatively (Ringer v albumin: 38.3 ± 5.0 g/L v 38.6 ± 4.5 g/L; p = 0.171) but differed intraoperatively (29.5 ± 5.2 g/L v 41.5 ± 6.0 g/L; p < 0.001). Creatinine kinase-myocardial band mass was higher in the Ringer (32.0 ± 34.8 μg/L) than in the albumin group (24.3 ± 33.0 μg/L) (p < 0.001). Aortic cross-clamping time associated with CK-MBm in the whole cohort (standardized β = 0.376 [95% CI 0.315-0.437], p < 0.001) and the Ringer group (β = 0.363 [0.273-0.452]; p < 0.001). Albumin administration in the whole cohort (β = -0.156 [-0.201 to -0.111]; p < 0.001) and high intraoperative albumin concentration in the Ringer group (β = -0.07 [-0.140 to -0.003]; p = 0.04) associated with reduced CK-MBm. Compared with ischemia-induced increase in CK-MBm, albumin's potency to reduce CK-MBm was 41% in the whole cohort (β-value ratio of -0.156/0.376) and 19% in the Ringer group (β-value ratio of -0.07/0.363).

CONCLUSION

Both endogenous and exogenous albumin appear to be cardioprotective regarding CK-MBm release in on-pump cardiac surgery.

Albumin Infusion and Blood Loss After Cardiac Surgery

BACKGROUND

In the recent ALBICS (ALBumin In Cardiac Surgery) trial, 4% albumin used for cardiopulmonary bypass priming and volume replacement increased perioperative bleeding compared with Ringer acetate. In the present exploratory study, albumin-related bleeding was further characterized.

METHODS

Ringer acetate and 4% albumin were compared in a randomized, double-blinded fashion in 1386 on-pump adult cardiac surgery patients. The study end points for bleeding were the Universal Definition of Perioperative Bleeding (UDPB) class and its components.

RESULTS

The UDPB bleeding grades were higher in the albumin group than the Ringer group: "insignificant" (albumin vs Ringer: 47.5% vs 62.9%), "mild" (12.7% vs 8.9%), "moderate" (28.7% vs 24.4%), "severe" (10.2% vs 3.2%), and "massive" (0.9% vs. 0.6%; P < .001). Patients in the albumin group received red blood cells (45.2% vs 31.5%; odds ratio [OR], 1.80; 95% CI, 1.44-2.24; P < .001), platelets (33.3% vs 21.8%; OR, 1.79; 95% CI, 1.41-2.28; P < .001), and fibrinogen (5.6% vs 2.6%; OR, 2.24; 95% CI, 1.27-3.95; P < .05), and underwent resternotomy (5.3% vs 1.9%; OR, 2.95; 95% CI, 1.55-5.60, P < .001) more often than patients in the Ringer group. The strongest predictors of bleeding were albumin group allocation (OR, 2.18; 95% CI, 1.74-2.74) and complex (OR, 2.61; 95% CI, 2.02-3.37) and urgent surgery (OR, 1.63; 95% CI, 1.26-2.13). In interaction analysis, the effect of albumin on the risk of bleeding was stronger in patients on preoperative acetylsalicylic acid.

CONCLUSIONS

Perioperative administration of albumin, compared with Ringer's acetate, resulted in increased blood loss and higher UDBP class. The magnitude of this effect was similar to the complexity and urgency of the surgery.

Effect of 4% Albumin Solution vs Ringer Acetate on Major Adverse Events in Patients Undergoing Cardiac Surgery With Cardiopulmonary Bypass: A Randomized Clinical Trial

IMPORTANCE

In cardiac surgery, albumin solution may maintain hemodynamics better than crystalloids and reduce the decrease in platelet count and excessive fluid balance, but randomized trials are needed to compare the effectiveness of these approaches in reducing surgical complications.

OBJECTIVE

To assess whether 4% albumin solution compared with Ringer acetate as cardiopulmonary bypass prime and perioperative intravenous volume replacement solution reduces the incidence of major perioperative and postoperative complications in patients undergoing cardiac surgery.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, double-blind, single-center clinical trial in a tertiary university hospital during 2017-2020 with 90-day follow-up postoperatively involving patients undergoing on-pump coronary artery bypass grafting; aortic, mitral, or tricuspid valve surgery; ascending aorta surgery without hypothermic circulatory arrest; and/or the maze procedure were randomly assigned to 2 study groups (last follow-up was April 13, 2020).

INTERVENTIONS

The patients received in a 1:1 ratio either 4% albumin solution (n = 693) or Ringer acetate solution (n = 693) as cardiopulmonary bypass priming and intravenous volume replacement intraoperatively and up to 24 hours postoperatively.

MAIN OUTCOMES AND MEASURES

The primary outcome was the number of patients with at least 1 major adverse event: death, myocardial injury, acute heart failure, resternotomy, stroke, arrhythmia, bleeding, infection, or acute kidney injury.

RESULTS

Among 1407 patients randomized, 1386 (99%; mean age, 65.4 [SD, 9.9] years; 1091 men [79%]; 295 women [21%]) completed the trial. Patients received a median of 2150 mL (IQR, 1598-2700 mL) of study fluid in the albumin group and 3298 mL (IQR, 2669-3500 mL) in the Ringer group. The number of patients with at least 1 major adverse event was 257 of 693 patients (37.1%) in the albumin group and 234 of 693 patients (33.8%) in the Ringer group (relative risk albumin/Ringer, 1.10; 95% CI, 0.95-1.27; P = .20), an absolute difference of 3.3 percentage points (95% CI, -1.7 to 8.4). The most common serious adverse events were pulmonary embolus (11 [1.6%] in the albumin group vs 8 [1.2%] in the Ringer group), postpericardiotomy syndrome (9 [1.3%] in both groups), and pleural effusion with intensive care unit or hospital readmission (7 [1.0%] in the albumin group vs 9 [1.3%] in the Ringer group).

CONCLUSIONS AND RELEVANCE

Among patients undergoing cardiac surgery with cardiopulmonary bypass, treatment with 4% albumin solution for priming and perioperative intravenous volume replacement solution compared with Ringer acetate did not significantly reduce the risk of major adverse events over the following 90 days. These findings do not support the use of 4% albumin solution in this setting.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02560519.

Effect and safety of 4% albumin in the treatment of cardiac surgery patients: study protocol for the randomized, double-blind, clinical ALBICS (ALBumin In Cardiac Surgery) trial

Background

In cardiac surgery with cardiopulmonary bypass (CPB), large amounts of fluids are administered. CPB priming with crystalloid solution causes marked hemodilution and fluid extravasation. Colloid solutions may reduce fluid overload because they have a better volume expansion effect than crystalloids. The European Medicines Agency does not recommend the use of hydroxyethyl starch solutions (HES) due to harmful renal effects. Albumin solution does not impair blood coagulation but the findings on kidney function are conflicting. On the other hand, albumin may reduce endothelial glycocalyx destruction and decrease platelet count during CPB. No large randomized, double-blind, clinical trials have compared albumin solution to crystalloid solution in cardiac surgery.

Methods/design

In this single-center, double-blind, randomized controlled trial comprising 1386 adult cardiac surgery patients, 4% albumin solution will be compared to Ringer’s acetate solution in CPB priming and volume replacement up to 3200 mL during surgery and the first 24 h of intensive care unit stay. The primary efficacy outcome is the number of patients with at least one major adverse event (MAE) during 90 postoperative days (all-cause death, acute myocardial injury, acute heart failure or low output syndrome, resternotomy, stroke, major arrhythmia, major bleeding, infection compromising post-procedural rehabilitation, acute kidney injury). Secondary outcomes are total number of MAEs, incidence of major adverse cardiac events (MACE; cardiac death, acute myocardial injury, acute heart failure, arrhythmia), amount of each type of blood product transfused (red blood cells, fresh frozen plasma, platelets), total fluid balance at the end of the intervention period, total measured blood loss, development of acute kidney injury, days alive without mechanical ventilation in 90 days, days alive outside intensive care unit at 90 days, days alive at home at 90 days, and 90-day mortality.

Discussion

The findings of this study will provide new evidence regarding efficacy and safety of albumin solution in adult patients undergoing cardiac surgery with CPB.

Trial registration

EudraCT (clinicaltrialsregister.eu) 2015–002556-27 Registered 11 Nov 2016 and ClinicalTrials.gov NCT02560519. Registered 25 Sept 2015.

Relation of Use of Red Blood Cell Transfusion After Acute Coronary Syndrome to Long-Term Mortality

Registry studies have associated red blood cell (RBC) transfusion with increased in-hospital mortality in patients with acute coronary syndrome (ACS). The impact on long-term mortality after 1-year follow-up remains unknown. Consecutive patients with ACS (n = 2,009) of a prospective Genetic Predisposition of Coronary Artery Disease cohort were followed for a median of 8.6 years (95% confidence interval [CI] 8.59 to 8.69). After discharge, 1,937 (96%) patients survived for over 30 days. Of those survivors, a subgroup of previously transfusion-naïve patients 85/1,937 (4.4%) who had received at least 1 RBC transfusion during hospitalization were compared with 1,278/1,937 patients (66.0%) who had not received any transfusion either during the hospitalization or the entire follow-up. Unadjusted long-term mortality was significantly higher in the patients transfused with RBC compared with their counterparts not transfused with RBC (58.8% vs 20.3%, p <0.001). The results remained significant for hazard ratio (HR) 1.91, 95% CI 1.39 to 2.63, p <0.001, after multivariate Cox proportional hazards model analysis and were similar after 1-year landmark analysis (HR 1.90, 95% CI 1.34 to 2.70, p <0.001). The higher all-cause mortality was largely explained by cancer mortality (15.3% vs 4.1%, p <0.001) and cardiovascular mortality (34.1% vs 12.1%, p <0.001). After 1:1 propensity score matching (n = 65 vs 65), the association of RBC transfusion with worse survival remained significant (HR 2.70, 95% CI 1.48 to 4.95, p = 0.001). Inverse probability weighted Cox analyses turned out similar results (HR 2.07, 95% CI 1.38 to 3.11, p <0.001). In conclusion, the strong association of need for RBC transfusion with increased mortality continued for patients with ACS even after a 1-year follow-up.

[Prophylactic platelet transfusions]

The consumption of platelet products in Finland is exceptionally high. For the most part, platelets are transfused pre-operatively to thrombocytopenic patients in order to prevent hemorrhage. Most of the minor procedures could, however, be conducted even if the patients'platelet levels would be lower than usual. In cardiac surgery, platelets are used because of the hemorrhagic diathesis associated with platelet inhibitors. Platelet inhibitors will, however, also bind to transfused platelets, whereby instead of prophylactic platelet transfusions it would be more sensible to leave the thorax open and not carry out ineffective platelet transfusions until the effect of the inhibitors has run out. We outline the prophylactic use of platelets based on recent international clinical practice guidelines.

Amplatzer Device in Bronchial Stump Fistula after Extrapleural Pneumonectomy

Endoscopically superimposed Amplatzer (St. Jude Medical, St. Paul, Minnesota, United States) septal occluder plug was successfully used in the treatment of septic right main bronchus fistula having developed after extrapleural pneumonectomy and heated chemotherapy in two patients with malignant pleural mesothelioma. In the first case the method was curative and in the other Amplatzer served as temporary bridging allowing rehabilitation from empyema and sepsis. After 4.5 and 4.2 years both patients are alive with no sign of relapse of mesothelioma or infection.

[Bleeding during operations]

Unnecessary use of blood products should be avoided, but excessive caution may on the other hand lead to complications and increase mortality. Attempts to more closely define the indications for use of blood products and reduce perioperative bleeding have over the past five years resulted in an approximately 20% decrease in the consumption of red blood cells. A generally applicable hemoglobin limit for red blood cell transfusions cannot be defined. The guideline often cited in recommendations (80 g/l) is subject to justifiable criticism, whereby a more liberal threshold for transfusion can be favored. Sparing fluid therapy of a surgical patient has been shown to promote recovery and reduce complications.

Indications for early fresh frozen plasma, cryoprecipitate, and platelet transfusion in trauma

BACKGROUND

Massive blood transfusion can be lifesaving in the treatment of severe trauma. Guidelines for the use of non-RBC blood components in the early phase of trauma resuscitation are largely based on extensions of expert recommendations for general surgery.

METHODS

The logic and evidence for the use of plasma, platelets, and cryoprecipitate early in the course of massive transfusion for trauma were reviewed. Large series of consecutive patients were sought.

FINDINGS

Resuscitation of the most severely injured and massively hemorrhaging patients usually starts with crystalloid fluids and progresses to uncross-matched RBC. Low blood volume, insensible losses, consumption, and resuscitation with plasma poor RBC concentrates rapidly lead to plasma coagulation factor concentrations of less than 40%. This typically occurs before 10 U of RBC have been transfused. Early initiation of plasma therapy is often delayed by its lack of immediate availability in the trauma center. Platelets usually fall to concentrations of 50-100 x 10(9)/L after 10-20 units of RBC have been given, but platelet concentrations in individual patients are quite variable and can decrease more quickly. Ideal platelet concentrations in trauma patients are not known, but are generally held to be greater than 50 x 10(9)/L. Cryoprecipitate can rapidly increase the concentrations of fibrinogen and von Willebrand's factor, but the advantages of higher than normal concentrations are speculative.

CONCLUSIONS

Early use of plasma and platelets at the upper end of recommended doses appears to reduce the incidence of coagulopathy in massively transfused individuals.

Optimizing the use of blood products in trauma care

Blood transfusion has been used to treat the injured since the US Civil War. Now, it saves the lives of tens of thousands of injured patients each year. However, not everyone who receives blood benefits, and some recipients are injured by the transfusion itself. Effective blood therapy in trauma management requires an integration of information from diverse sources, including data relating to trauma and blood use epidemiology, medical systems management, and clinical care. Issues of current clinical concern in highly developed trauma systems include how to manage massive transfusion events, how to limit blood use and so minimize exposure to transfusion risks, how to integrate new hemorrhage control modalities, and how to deal with blood shortages. Less developed trauma systems are primarily concerned with speeding transport to specialized facilities and assembling trauma center resources. This article reviews the factors that effect blood use in urgent trauma care.

The effects of aprotinin and tranexamic acid on thrombin generation and fibrinolytic response after cardiac surgery

BACKGROUND

Thrombin formation during cardiac surgery could result in disordered hemostasis and thrombosis. The aim of the study was to examine the effects of aprotinin and tranexamic acid on thrombin generation and fibrinolytic activity in patients undergoing cardiac surgery.

METHODS

Data were collected prospectively from 60 patients undergoing coronary artery bypass grafting using cardiopulmonary bypass (CPB). In a randomized sequence, 20 patients received aprotinin, 20 patients received tranexamic acid, and in 20 patients placebo was used.

RESULTS

Significant thrombin activity was found in all the studied patients. Thrombin generation was less in the aprotinin group than in the tranexamic acid and the placebo group (thrombin/anti-thrombin III complexes 33.7 +/- 3.6, 53.6 +/- 7.0 and 44.2 +/- 5.3 microg/l 2 h after CPB and F1 + 2 fragment 1.50 +/- 0.10, 2.37 +/- 0.37 and 2.04 +/- 0.20 nmol/l 6 h after surgery, respectively). The inhibition of fibrinolysis was significant with both anti-fibrinolytic drugs (D-dimers 0.427 +/- 0.032, 0.394 +/- 0.039 and 2.808 +/- 0.037 mg/l 2 h after CPB, respectively). The generation of d-dimers was inhibited until 16 h after CPB in the aprotinin group. The plasminogen activation was significantly less in the aprotinin group (plasmin/anti-plasmin complexes 0.884 +/- 0.095, 2.764 +/- 0.254 and 1.574 +/- 0.185 mg/l 2 h after CPB, respectively).

CONCLUSION

Thrombin formation is inevitable in coronary artery bypass surgery when CPB is used. The suppression of fibrinolytic activity, either with aprotinin or with tranexamic acid interferes with the hemostatic balance as evaluated by biochemical markers. Further investigations are needed to define the role of hemostatic activation in ischemic complications associated with cardiac surgery.

Massive blood transfusion exceeding 50 units of plasma poor red cells or whole blood: the survival rate and the occurrence of leukopenia and acidosis

The survival rate after bleeding requiring massive blood transfusions exceeding 50 units has been reported to be low or zero. There seems to be no reports of leukopenia in connection with massive blood transfusion. This retrospective study was carried out to investigate the survival rate and the occurrence of leukopenia and acidosis in patients who were transfused with more than 50 units of plasma poor red cells or whole blood. The survival rate was 16 of 23. Three of the five patients with a blood transfusion of over 100 units survived. Pure component therapy was used on 18 occasions. All patients had a leukopenia, which lasted up to five days. All patients had an acidosis. The range of the lowest pH values in patients who did not survive was from 6.77 to 7.27 and in survivors from 6.87 to 7.28. The survival rate was considerably higher than reported in previous studies. Pure component therapy appeared to be particularly suited to massive transfusion. Leukopenia was a regular phenomenon. Severe acidosis did not predict a poor outcome.

Replacement of massive blood loss

Treatment of massive blood loss has experienced major changes during the recent decade. The transition towards pure component therapy has been the most significant issue, which has compelled the clinician to revise some of their basic strategies in treatment of massively bleeding patients. The importance of adequate volume resuscitation with crystalloids and colloids is still unrefutable, but the therapy of hemorrhagic derangements has changed. Plasma-poor red cells (RC) are now commonly used instead of whole blood (WB) or packed red blood cells (PRBC) to correct oxygen carrying capacity during massive blood loss. As the plasma content of RC is minimal, deficit of plasma and coagulation factors develops earlier than during transfusion of WB and PRBC. Hypofibrinogenemia develops first followed by other coagulation factor deficits and later by thrombocytopenia. Therefore the use of fresh frozen plasma (FFP) is the primary intervention to treat abnormal bleeding encountered in the replacement of massive blood loss with RC. As the development of thrombocytopenia is a highly individual phenomenon, the transfusion of platelets should be guided by repeatedly determined platelet counts.

Perioperative volume effect of HES 120/0.7 compared with dextran 70 and Ringer acetate

Hydroxyethyl starch 120 (HES 120/0.7, Plasmafusin) is the smallest medium molecular weight HES preparation used as a plasma substitute for all clinical purposes. We compared the volume and colloid osmotic effect of 6% HES 120 with 6% dextran 70 and Ringer's solution during and after surgery with minimal blood loss. Patients (n = 48) having general anaesthesia were randomly divided into six groups. A thirty-minute bolus infusion was started at the induction of anaesthesia, and thereafter the infusions were continued at two different rates for five hours. The volume of the bolus was 10% and 30% of the calculated volume (CPV) in colloid and Ringer groups, respectively. The constant infusion rates were 2% and 6% of the CPV for the colloids, and 10% and 20% for the two Ringer groups. Blood samples for the measurement of serum proteins and colloid osmotic pressure (COP) were obtained before induction, after the bolus, and thereafter hourly throughout the study. Albumin, prealbumin and total serum protein concentrations were used to calculate relative plasma volumes. After the bolus infusion, plasma volumes increased significantly in all six groups and the increments were sustained throughout the study. At the lower infusion rates of the volume changes of HES and Ringer groups were almost identical and comparable to dextran group up to the third floor. At the higher infusion rates, dextran 70 produced greater plasma volume expansions than HES 120, and the volume effect of Ringer's solution was clearly exceeded by both colloids. The hourly estimated half-lives of dextran were constantly longer compared with HES. With both infusions rates the COPs of dextran and HES groups were higher compared with Ringer groups. There were no differences in COP between the dextran and HES groups. It is concluded, that in this clinical setting the volume effect of 6% dextran 70 exceeds that of the HES 120/0.7, and that both colloids are superior to Ringer's solution.

Tranexamic acid (Cyklokapron) reduces perioperative blood loss associated with total knee arthroplasty

In this prospective, randomized, double-blind study, we have investigated the effect of an antifibrinolytic agent, tranexamic acid (Cyklokapron), on blood loss and transfusion requirements associated with total knee arthroplasty. Twenty-nine patients were allocated randomly to receive either tranexamic acid 15 mg kg-1 or an equal volume of placebo a few minutes before a tourniquet was deflated. Blood loss during surgery, in the recovery room and on the surgical ward was recorded, together with the number of units of blood transfused in hospital. Mean blood loss during surgery was 428 (SD 254) ml in the tranexamic acid group (n = 15) compared with 415 (244) ml in the placebo group (n = 13). In the recovery room the tranexamic acid group lost 127 (95) ml and the placebo group 576 (245) ml (P < 0.001). On the ward the respective volumes were 293 (200) ml and 558 (293) ml (P < 0.01). Total blood loss was 847 (356) ml in the tranexamic acid group and 1549 (574) ml in the placebo group (P < 0.001). During the hospital stay the treatment group received 1.5 (1.3) units of blood compared with 3.3 (1.8) in the control group (P < 0.005). Two patients in the placebo group experienced a thrombotic complication compared with none in the treatment group. We conclude that tranexamic acid reduced perioperative blood loss and transfusion requirements associated with total knee arthroplasty.

Replacement of major surgical blood loss by hypo-oncotic or conventional plasma substitutes

The purpose of the study was to examine the effects of hypooncotic 4% hydroxyethyl starch 120/0.7, 3% dextran 70, 5% albumin and hyperoncotic 6% hydroxyethyl starch 120/0.7 on the perioperative colloid osmotic pressure (COP), albumin and protein concentrations and fluid balance. The plasma substitutes were used with red cell concentrates to replace blood loss with equal volume in sixty major abdominal or urological surgeries. A special effort was made to keep replacements and losses at even volumes constantly and to avoid fluctuation of blood volume. The blood specimen were obtained before induction, after each 20% blood loss, at the end of the recovery room phase and on the three following postoperative mornings. There were significant differences in the peroperative and immediate postoperative COPs. However, these differences had vanished by the first postoperative morning. COP was preserved above 16 mmHg in all groups throughout the study. The identical peroperative albumin and protein concentrations of the synthetic colloid groups suggests that their volume effect was the same, regardless of the varying COP. During the observation period there were no significant differences among the groups concerning the diuresis and the fluid balances. We conclude, that the hypooncotic 4% HES 120 and 3% dextran 70 solutions provide the same clinical effect as 6% HES 120 solution. Consequently less colloid is needed, which allows the use of greater volumes of the dilute colloid solutions in replacement therapy.

Albumin, HES 120 and dextran 70 as adjuvants to red blood cell concentrates: a study on colloid osmotic pressure changes in vitro

An in vitro model of surgical bleeding was developed to simulate continuous blood loss and replacement therapy with plasma substitutes and red cell concentrates. The model was used to determine the lowest colloid concentration in vitro for each of the plasma substitutes that sustains colloid osmotic pressure above 2.4 kPa (or 18 mmHg) when used up to the recommended maximal total dose. Plasma, supernatant separated from red cell concentrates and dextran 70, hydroxyethyl starch 120 or albumin were mixed to create dilutions imitating plasma composition in the course of clinical blood loss and replacement therapy. The relative volume of each component was calculated according to the model when the bleeding was equal to multiples of 10% of blood volume up to a blood loss of 120%. Our measurements indicate that the colloid concentrations of 5.0% for albumin, 4.0% for hydroxyethyl starch 120 and 3.5% for dextran 70 preserve colloid osmotic pressure above 2.4 kPa.

Intravenous regional anaesthesia of the arm. Effect of the technique of exsanguination on the quality of anaesthesia and prilocaine plasma concentrations

The effects of different techniques of exsanguination of the upper arm during intravenous regional anaesthesia on prilocaine plasma concentrations, quality of anaesthesia, toxic symptoms after deflation of the tourniquet and injection pressure of the anaesthetic were studied in 10 healthy male volunteers. The nondominant arm was exsanguinated using either Esmarch's bandage or elevation of the arm for 2 minutes plus arterial occlusion by compression of the brachial artery. The injection pressure after the prilocaine dose (3 mg/kg) was significantly higher in the elevation group (maximally 98 mmHg). There were no statistically significant differences in the onset of, or recovery from, anaesthesia between the groups. Various mild toxic symptoms were experienced in the central nervous system after deflation of the tourniquet. However, there was no correlation between the two techniques and the degree of severity of the toxic symptoms. The highest single venous plasma concentration (total) of prilocaine was 2.3 micrograms/ml measured from the contralateral cubital vein (elevation group, 2 minutes). The differences in prilocaine concentrations between the groups were not statistically significant.