Sinikka Kukkonen

Gelatin and hydroxyethyl starch, but not albumin, impair hemostasis after cardiac surgery.

We investigated the effect of postoperative administration of colloids on hemostasis in 45 patients after cardiac surgery. Patients were randomized to receive 15 mL kg−1 of either 4% albumin, 4% succinylated gelatin, or 6% hydroxyethyl starch (molecular weight of 200 kDa/degree of substitution 0.5) as a short-term infusion. There was a comparable decrease in maximum clot firmness of thromboelastometry tracings in gelatin and hydroxyethyl starch groups immediately after completion of the infusion, whereas these values remained unchanged in the albumin group. The impairment in clot strength persisted up to 2 h, although the values partly recovered. Postoperative bleeding correlated inversely with the clot strength in pooled data of the artificial colloids. Fibrin formation (clot formation time, &agr;-angle) and fibrinogen-dependent clot strength (maximum clot firmness and shear elastic modulus) were more disturbed in the hydroxyethyl starch group than in the gelatin group. We conclude that after cardiopulmonary bypass surgery, both gelatin and hydroxyethyl starch impair clot strength and fibrin buildup, which may predispose patients to increased blood loss. The greatest impairment in hemostasis was seen after hydroxyethyl starch administration, whereas albumin appeared to have the least effect on hemostatic variables.

Usefulness of extracorporeal membrane oxygenation as a bridge to lung transplantation: A descriptive study

BACKGROUND This retrospective study investigated early outcome in patients with end-stage pulmonary disease bridged with extracorporeal membrane oxygenation (ECMO) with the intention of lung transplantation (LTx) in 2 Scandinavian transplant centers. METHODS ECMO was used as a bridge to LTx in 16 patients between 2005 and 2009 at Sahlgrenska and Helsinki University Hospitals. Most patients were late referrals for LTx, and all failed to stabilize on mechanical ventilation. Thirteen patients (7 men) who were a mean age of 41 ± 8 years (range, 25-51 years) underwent LTx after a mean ECMO support of 17 days (range, 1-59 days). Mean follow-up at 25 ± 19 months was 100% complete. RESULTS Three patients died on ECMO while waiting for a donor, and 1 patient died 82 days after LTx; thus, by intention-to-treat, the success for bridging is 81% and 1-year survival is 75%. All other patients survived, and 1-year survival for transplant recipients was 92% ± 7%. Mean intensive care unit stay after LTx was 28 ± 18 days (range, 3-53 days). All patients were doing well at follow-up; however, 2 patients underwent retransplantation due to bronchiolitis obliterans syndrome at 13 and 21 months after the initial ECMO bridge to LTx procedure. Lung function was evaluated at follow-up, and mean forced expiratory volume in 1 second was 2.0 ± 0.7 l (62% ± 23% of predicted) and forced vital capacity was 3.1 ± 0.6 l (74% ± 21% of predicted). CONCLUSION ECMO used as a bridge to LTx results in excellent short-term survival in selected patients with end-stage pulmonary disease.

Rapidly Degradable Hydroxyethyl Starch Solutions Impair Blood Coagulation After Cardiac Surgery : A Prospective Randomized Trial

BACKGROUND: There is continuing concern about the effect of hydroxyethyl starch (HES) solutions on blood coagulation. Rapidly degradable HES solutions with more favorable effects on clot strength have therefore been developed. Because the risk of bleeding is increased after cardiopulmonary bypass, we examined whether these types of HES solutions could be administered after cardiac surgery without an alteration of coagulation. METHODS: Two new rapidly degradable HES solutions were compared with human albumin in 45 patients scheduled for elective primary cardiac surgery. After admission to the cardiac surgical intensive care unit, the patients were allocated in random order to receive either 15 mL/kg of HES solution with low molecular weight and low molar substitution (either 6% HES200/0.5 or 6% HES130/0.4) or 4% human albumin solution as a short-time (70–240 min) infusion. RESULTS: Clot formation time was prolonged and maximum clot firmness was decreased in thromboelastometry tracings after infusion of both HES solutions. This impairment in thromboelastometry tracings partly recovered (using InTEM® and ExTEM® coagulation activators) at 2 h after the completion of the study infusion. Platelet contribution to maximum clot firmness remained unaffected in all of the study groups. HES did not induce fibrinolysis. No changes in thromboelastometry tracings were observed after human albumin infusion. Chest tube drainage was comparable in the study groups. CONCLUSIONS: We conclude that a short-time infusion of rapidly degradable HES solutions after cardiac surgery produces impairment in fibrin formation and clot strength in thromboelastometry tracings. In this clinical setting, human albumin does not impair hemostasis.

Natural course and risk factors for impaired renal function during the first year after heart transplantation

BACKGROUND Post-operative renal failure is a common and potentially hazardous complication after heart transplantation (HTx). In this study we characterized pre- and post-operative risk factors for acute renal failure requiring renal replacement therapy (RRT). METHODS Ninety-three patients underwent orthotopic HTx between 2000 and 2007. The risk factors for RRT during the early post-operative period and predictors contributing to impaired renal function within the first post-transplant year were analyzed by regression analysis. The impact of pre-operative renal failure and early post-operative RRT on renal function within 1 year were studied. RESULTS Before HTx, 55% of patients (51 of 93) had normal renal function or mild renal failure (glomerular filtration rate [GFR] >60 ml/min/1.73 m(2)). Before discharge from the hospital, 25% (23 of 93) developed acute renal failure and required RRT. Of these, 16% (8 of 51) had pre-operatively normal renal function or mild renal failure, and 36% (15 of 42) had moderate or severe renal failure (GFR <60 ml/min/1.73 m(2); p = 0.02). The prognosticators for early RRT were prolonged graft dysfunction, re-admission to the operating room due to post-operative bleeding, poor diuresis during surgery (<1,000 ml), pre-operative pacemaker implantation, intubation time >24 hours, pre-operative GFR <60 ml/min/1.73 m(2), post-operative troponin T >6 microg/liter and pre-operative use of angiotensin receptor blocker. CONCLUSIONS Pre-operative renal failure is a significant risk factor for RRT during the immediate post-operative period and requires aggressive treatment. Patients with pre-operative renal failure secondary to severe heart failure and acute post-operative renal failure requiring RRT tend to recover within the first year post-HTx.

Haemodynamics and acid-base equilibrium after cardiac surgery: comparison of rapidly degradable hydroxyethyl starch solutions and albumin.

Background: Stable haemodynamics is often achieved by administration of colloids after cardiac surgery. We conducted a prospective, randomized, open-label study comparing haemodynamics and acid-base equilibrium after infusion of two rapidly degradable hydroxyethyl starch (HES) solutions or human albumin (HA) to cardiac surgical patients. Materials and Methods: 45 patients received a predetermined fixed dose of 15 ml kg−1 of either 6% HES (MW 130 kDa, n=15), 6% HES (MW 200 kDa, n=15) or 4% HA (MW 69 kDa, n=15) after on-pump cardiac surgery. Results: Left ventricular filling pressures assessed using pulmonary artery catheter responded similarly in all groups. Mean (SD) cardiac index was higher in HES130 [3.5 1 min−1 m−2 (0.7)] and HES200 [3.5 1 min−1 m−2 (0.5)] than in HA [2.8 1 min−1 m−2 (0.6)] group after completion of infusion (P=0.002) but no differences were detected at 2 and 18 hours. Oxygen delivery increased in both HES groups but not in HA group. After cessation of infusion base excess was the most negative in HA group. At 2 hours mean (SD) base excess was higher in HWS130 [0 (1.32)] than in HES200 [-1.32 (2.27)] and HA [-2.3 (1.3)] group (P=0.002, between the groups). Conclusions: We conclude that the effect of albumin on cardiac performance is inferior than that of HES130 or HES200 in early postoperative phase after cardiac surgery. HES130 induces no alterations in acid-base equilibrium whereas a negative base excess was observed after HA infusion.

Comparison of the effect of 6% hydroxyethyl starch and gelatine on cardiac and stroke volume index: a randomized, controlled trial after cardiac surgery

Background and aims: The objective of this study was to find out the effect of various doses of hydroxyethyl starch (HES), gelatine or Ringer’s acetate on cardiac and stroke volume index after cardiac surgery. Material and methods: Three consecutive boluses (each 7 mL·kg-1) of either 6% HES 130/0.4, 4% gelatine, or Ringer’s acetate solutions were administered to 45 patients postoperatively. The rate of infusions was adjusted according to haemodynamic measurements. Thereafter, infusion of the study solution (7 mL·kg-1) was continued for the following 12 hours. The total dose of study solution was 28 mL·kg-1. Results and conclusion: Mean (SD) cardiac and stroke volume indices were greater in the HES group [2.8 L·min-1.m-2 (0.7), 34.1 (6.7) ml·m -2] than in the gelatine group [2.2 L·min-1.m -2 (0.6), 25.8 (7.2) ml·m-2] after completion of 7 mL·kg-1 of study solution. At this stage, the effect of gelatine did not differ from Ringer’s acetate. After completion of 14 mL·kg-1 and 21 mL·kg-1 of colloids, similar cardiac and stroke volume indices were observed and the haemodynamic response was better in both colloid groups than in the Ringer’s acetate group. No differences between groups were detected on the first postoperative morning. In the early postoperative phase after cardiac surgery, the effect of a single dose of HES solution on the haemodynamics was superior to the effect of gelatine or Ringer’s acetate. However, after repeated administration of the study solutions, the haemodynamics in the two colloid groups appeared to be similar, but superior to the Ringer’s acetate group.

Tranexamic acid does not correct the haemostatic impairment caused by hydroxyethyl starch (200 kDa/0.5) after cardiac surgery.

We investigated the effect of intravenous tranexamic acid on hydroxyethyl starch (HES)-induced clot strength impairment after cardiac surgery. Patients were randomized to receive either 1 g tranexamic acid or the same volume of 0.9% saline after administration of 15 ml/kg of 6% HES (molecular weight, 200 kDa; degree of substitution, 0.5) in the immediate postoperative period. Modified thromboelastometry (ROTEM) using different activators [intrinsic ROTEM (InTEM), extrinsic ROTEM (ExTEM), fibrinogen ROTEM (FibTEM)] was carried out to evaluate clot formation and lysis. The clot formation time was prolonged, and the maximum clot firmness (MCF) and shear elastic modulus [G = 5000 × MCF / (100−MCF), dynes/cm2] decreased (all activators of ROTEM) after completion of HES (P < 0.001, two-factor analysis of variance). These abnormalities in blood coagulation persisted despite tranexamic acid. Maximal lysis (FibTEM), indicative of fibrinolytic activity, was increased after HES but no effect of tranexamic acid was observed. The cumulative chest tube drainage until the first postoperative morning was not different between the groups (1008 ± 251 and 1081 ± 654 ml, P = 0.698, respectively). We conclude that after cardiopulmonary bypass, HES-induced impairment in clot formation and strength, or increased fibrinolytic capacity, is not reversed by the administration of tranexamic acid.

A Comparison of the Haemodynamic Effects of 4% Succinylated Gelatin, 6% Hydroxyethyl Starch (200/0.5) and 4% Human Albumin after Cardiac Surgery

Background and Aims: The goal for volume replacement therapy is to maintain stable haemodynamics after cardiac surgery. We hypothesized that a short term infusion of hydroxyethyl starch results in better haemodynamic response than an infusion of lower molecular weight gelatin. Material and Methods: 45 patients received a predetermined fixed dose of 15 ml kg−1 of either 4% succinylated gelatin (GEL) or 6% hydroxyethyl starch (HES) or 4% human albumin (HA) after cardiac surgery. Results and Conclusions: Pulmonary capillary wedge pressure was more increased in GEL and HES groups [mean (SD) 153% (54) and 168% (57) of pre-infusion value] than in HA group [122% (23)] (P = 0.031) after completion of infusion, but no differences in cardiac index (CI) and stroke volume index (SVI) were observed. At 2 and 18 hours after end of study infusions SVI was more increased in HES [143% (38) and 148% (41) of pre-infusion values] and HA [143% (35) and 163% (42) of pre-infusion values] groups than in GEL [116% (23) and 125% (30)] group (P = 0.047 at 2 hours and P = 0.033 at 18 hours). In early postoperative phase after cardiac surgery, HES and HA infusions improve haemodynamics more and longer period than GEL infusion.

Vasopressin, When Added to Norepinephrine, Was Not Associated with Increased Predicted Mortality after Cardiac Surgery

Background and Aims: Arginin vasopressin (AVP) is a potent vasoconstrictor which has been used in vasodilatory shock when therapy with catecholamines and fluids has failed. In this study we evaluated the association of AVP with organ failure and mortality in cardiac surgical patients suffering from vasodilatory shock refractory to norepinephrine (NE) treatment. Material and Methods: Cardiac surgical patients who received AVP in addition to NE (N=33, AVP-group) and 33 control patients (NE group) who were treated with an equal dose of NE compared with AVP patients when AVP infusion started. Data on preoperative risk factors according to EuroSCORE and predicted mortality calculated by logistic EuroSCORE were collected preoperatively. Data on hemodynamics, organ dysfunctions, length of intensive care unit stay and mortality were collected. Results: EuroSCORE did not differ between the groups, AVP:10,4 ± 3,9 vs NE 8,9 ± 4.0. Observed 30 day mortality was lower than predicted in both groups, AVP: 7 (21,7%) vs. predicted mortality 25.9% and NE: 2 (6.1%) vs. 16.0%, respectively. There were more renal complications (36.4% vs. 9.1%, p=0,008) and infections (30.3% vs. 3.0%, p=0.003) in patients receiving AVP. Cardiovascular complications did not differ between the groups. Conclusions: In this prospectively observed cohort of cardiac surgical patients, AVP did not increase mortality predicted by Euroscore. Anyhow renal and infection complications were common.

Whole blood hypercoagulability despite anticoagulation during mechanical cardiac assist

We report hypercoagulability despite activated partial thromboplastin time (APTT)-guided heparin treatment during Berlin Heart®-supported circulation in a 38-year-old man with heart failure for 19 days. The patient was anticoagulated using unfractionated heparin, acetylsalicylic acid and dipyridamole. Contact and tissue factor-activated thromboelastometry revealed increased clot firmness, although anticoagulation assessed by APTT was in accordance with the treatment protocol. Strength of polymerized fibrin was also increased. We saw no clinical signs of thrombosis. Thromboelastometry normalized after heart transplantation. Our results suggest that hypercoagulability is due to excess fibrin formation. Monitoring anticoagulation using APTT may, therefore, be misleading during mechanical cardiac assist.