Unexpected left ventricular free-wall rupture following an aortic catheter-valve implantation.

Our experience with the Sapien trans-apical aortic valve (Edwards Lifesciences Inc., Irvine, CA, USA) has been straightforward without per-procedural mortality except in 1/16 consecutive cases who developed non-apical haemorrhage early after valve implantation. We describe the case of an 84-year-old female carrying a very high operative risk (logistic EuroScore of 44%), who underwent a trans-apical stent-valve implantation for severe and symptomatic aortic valve stenosis (23 mm). Due to massive blood loss, an emergency sternotomy and cannulation for cardiopulmonary bypass resuscitation were necessary to treat (without success) an unusual and unexpected subaortic left ventricular free-wall rupture that occurred few minutes after the stent-valve positioning and implantation. To the best of our knowledge, this is the first described case of a left ventricular free-wall rupture occurring after an otherwise non-complicated standard catheter-based aortic valve replacement.

Temporary caval stenting improves venous drainage during cardiopulmonary bypass

OBJECTIVES: Assess the benefit of temporary caval stenting for remote venous drainage during cardiopulmonary bypass (CPB). METHODS: Temporary caval stenting was realized in bovine experiments (65+/-6 kg) by the means of self-expanding (18F for insertion, 36F in situ) venous cannulas (Smartcanula LLC, Lausanne, Switzerland) with various lengths: 43 cm, 53 cm, 63 cm vs. a standard 28F wire armed cannula in trans-jugular fashion. Maximal blood flows were assessed for 20, 25 and 30 mmHg of driving pressure with a motorized table height adjustment system. In addition, the inferior caval diameters (just above its bifurcation) were measured in real time with intra-vascular ultrasound (IVUS). RESULTS: Venous drainage (flow in l/min) at 20 mmHg, 25 mmHg, and 30 mmHg drainage load was 3.5+/-0.5, 3.7+/-0.7 and 4.0+/-0.6 for the 28F standard vs. 4.1+/-0.7, 4.0+/-1.3 and 3.9+/-1.1 for the 36F smart 43 cm, vs. 5.0+/-0.7, 5.3+/-1.3 and 5.4+/-1.4 for the 36F smart 53 cm, vs. 5.2+/-0.5*, 5.6+/-1.1* and 5.8+/-1.0* for the 36F smart 63 cm. The inferior vena caval diameters at 30 mmHg were 13.5+/-4.8 mm for 28F standard, 11.1+/-3.6 for 36F smart 43 cm, 11.3+/-3.2 for 36F 53 cm, and 17.0+/-0.1* for 36F 63 cm (*P<0.05 for 28F standard vs. 36F smart 63 cm long) CONCLUSIONS: The 43 cm self-expanding 36F smartcanula outperforms the 28F standard wire armed cannula at low drainage pressures and without augmentation. Temporary caval stenting with long self-expanding venous cannulas provides even better drainage (+51%).

Enteral nutrition in critically ill patients with severe hemodynamic failure after cardiopulmonary bypass.

BACKGROUND & AIMS: The study was designed to investigate and quantify nutritional support, and particularly enteral nutrition (EN), in critically ill patients with severe hemodynamic failure. METHODS: Prospective, descriptive study in a surgical intensive care unit (ICU) in a university teaching hospital: patients aged 67+/-13 yrs (mean+/-SD) admitted after cardiac surgery with extracorporeal circulation, staying 5 days in the ICU with acute cardiovascular failure. Severity of disease was assessed with SAPS II, and SOFA scores. Variables were energy delivery and balance, nutrition route, vasopressor doses, and infectious complications. Artificial feeding delivered according to ICU protocol. EN was considered from day 2-3. Energy target was set 25 kcal/kg/day to be reached stepwise over 5 days. RESULTS: Seventy out of 1114 consecutive patients were studied, aged 67+/-17 years, and staying 10+/-7 days in the ICU. Median SAPS II was 43. Nine patients died (13%). All patients had circulatory failure: 18 patients required intra-aortic balloon-pump support (IABP). Norepinephrine was required in 58 patients (83%). Forty patients required artificial nutrition. Energy delivery was very variable. There was no abdominal complication related to EN. As a mean, 1360+/-620 kcal/kg/day could be delivered enterally during the first 2 weeks, corresponding to 70+/-35% of energy target. Enteral nutrient delivery was negatively influenced by increasing dopamine and norepinephrine doses, but not by the use of IABP. CONCLUSION: EN is possible in the majority of patients with severe hemodynamic failure, but usually results in hypocaloric feeding. EN should be considered in patients with careful abdominal and energy monitoring.

Is PaCO2 management optimal under controlled mechanical ventilation (CMV) during neuro-resuscitation?

INTRODUCTION. Both hypocapnia and hypercapnia can be deleterious to brain injured patients. Strict PaCO2 control is difficult to achieve because of patient's instability and unpredictable effects of ventilator settings changes. OBJECTIVE. The aim of this study was to evaluate our ability to comply with a protocol of controlled mechanical ventilation (CMV) aiming at a PaCO2 between 35 and 40 mmHg in patients requiring neuro-resuscitation. METHODS. Retrospective analysis of consecutive patients (2005-2011) requiring intracranial pressure (ICP) monitoring for traumatic brain injury (TBI), subarachnoid haemorrhage (SAH), intracranial haemorrhage (ICH) or ischemic stroke (IS). Demographic data, GCS, SAPS II, hospital mortality, PaCO2 and ICP values were recorded. During CMV in the first 48 h after admission, we analyzed the time spent within the PaCO2 target in relation to the presence or absence of intracranial hypertension (ICP[20 mmHg, by periods of 30 min) (Table 1). We also compared the fraction of time (determined by linear interpolation) spent with normal, low or high PaCO2 in hospital survivors and non-survivors (Wilcoxon, Bonferroni correction, p\0.05) (Table 2). PaCO2 samples collected during and after apnoea tests were excluded. Results given as median [IQR]. RESULTS. 436 patients were included (TBI: 51.2 %, SAH: 20.6 %, ICH: 23.2 %, IS: 5.0 %), age: 54 [39-64], SAPS II score: 52 [41-62], GCS: 5 [3-8]. 8744 PaCO2 samples were collected during 150611 h of CMV. CONCLUSIONS. Despite a high number of PaCO2 samples collected (in average one sample every 107 min), our results show that patients undergoing CMV for neuro- resuscitation spent less than half of the time within the pre-defined PaCO2 range. During documented intracranial hypertension, hypercapnia was observed in 17.4 % of the time. Since non-survivors spent more time with hypocapnia, further analysis is required to determine whether hypocapnia was detrimental per se, or merely reflects increased severity of brain insult.

Serum and CSF levels of neuron-specific enolase (NSE) in cardiac surgery with cardiopulmonary bypass: a marker of brain injury?

We investigated whether neuron-specific enolase (NSE) in serum or cerebrospinal fluid (CSF) reflects subtle or manifest brain injury in children undergoing cardiac surgery using cardiopulmonary bypass (CPB). NSE was measured in serum (s-NSE) before, and up to, 102 h after surgery in 27 children undergoing cardiac surgery with CPB. In 11 children, CSF-NSE was also measured 48 or 66 h post-surgery. As erythrocytes contain NSE, hemoglobin concentration in the samples was determined spectrophotometrically at 550 nm (cut-off limit: absorbance 0.4 = 560 mg/l) in 14 children and in a further 13 children by spectroscopic multicomponent analysis (cut-off limit 5 micromol/l = 80 mg/l). One hundred and one of 214 post-operative serum samples (47%) had to be discarded because of hemolysis (18% spectrophotometrically at 550 nm and 88% with spectroscopic multicomponent analysis). On the first and second post-operative day, the median s-NSE values were significantly higher when compared with samples taken after 54 h or longer (P = 0.008 and P = 0.002). All CSF-NSE levels were within the normal range and below the s-NSE measured in the same patient. Although in our study elevated s-NSE seems to indicate brain injury in CPB-surgery, the low concentration of NSE in the post-operative CSF of 11 children puts the neuronal origin of s-NSE in question. NSE from other non-neuronal tissues probably contributes to the elevated s-NSE. Additionally, normal post-operative CSF-NSE values in two children with post-operative neurological sequelae might question the predictive value of CSF-NSE with regard to brain injury.

Detection of Brazilian hantavirus by reverse transcription polymerase chain reaction amplification of N gene in patients with hantavirus cardiopulmonary syndrome

We report a nested reverse transcription-polymerase chain reaction (RT-PCR) assay for hantavirus using primers selected to match high homology regions of hantavirus genomes detected from the whole blood of hantavirus cardiopulmonary syndrome (HCPS) patients from Brazil, also including the N gene nucleotide sequence of Araraquara virus. Hantavirus genomes were detected in eight out of nine blood samples from the HCPS patients by RT-PCR (88.9% positivity) and in all 9 blood samples (100% positivity) by nested-PCR. The eight amplicons obtained by RT-PCR (P1, P3-P9), including one obtained by nested-PCR (P-2) and not obtained by RT-PCR, were sequenced and showed high homology (94.8% to 99.1%) with the N gene of Araraquara hantavirus. Although the serologic method ELISA is the most appropriate test for HCPS diagnosis, the use of nested RT-PCR for hantavirus in Brazil would contribute to the diagnosis of acute hantavirus disease detecting viral genomes in patient specimens as well as initial genomic characterization of circulating hantaviruses.

Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases.

OBJECTIVE: Assess the performance of self-expanding venous cannulas for routine use in open-heart surgery. METHODS: Prospective study in 100 unselected consecutive patients undergoing open-heart surgery with either remote or central smart venous cannulation. RESULTS: The study focuses on the 76 consecutive adult patients (mean age 59.2+/-17.3 years; 60 males, 16 females) undergoing surgical procedures with total cardiopulmonary bypass for either valve procedures (42/76 patients=55.3%), ascending aorta and arch repair (20/76 patients=26.3%), coronary artery revascularization (13/76 patients=17.1%) or other procedures (11/76 patients=14.5%) with 14/76 patients (18.4%) undergoing redo surgery and 6/76 patients (7.9%) undergoing small access surgery. The mean pump flow achieved by gravity drainage alone accounted for 5.0+/-0.6l/min (=114% of target) in the entire study population (n=76) as compared to the calculated, theoretical pump flow of 4.4+/-0.5l/min (p<0.0001). For the femoral cannulation sub-group (n=35) pump flow achieved by gravity drainage alone accounted for 4.9+/-0.6l/min (=114% of target) as compared to the calculated theoretical pump flow of 4.3+/-0.4l/min (p<0.0001). The corresponding numbers for trans-subclavian cannulation (n=7) are 5.2+/-0.5l/min (111%) for the pump flow achieved by gravity drainage as compared to the theoretical target flow of 4.7+/-0.4l/min. For the central cannulation sub-group (n=34) mean flow achieved by gravity drainage with a self-expanding venous cannula accounted for 5.1+/-0.7l/min (=116% of target) as compared to the calculated theoretical flow of 4.4+/-0.6l/min (p<0.0001). CONCLUSION: Full or more than target flow was achieved in 97% of the patients studied undergoing CPB with self-expanding venous cannulas and gravity drainage. Remote venous cannulation with self-expanding cannulas provides similar flows as central cannulation. Augmentation of venous return is no longer necessary.

Safety and Effectiveness of two treatment regimes with tranexamic acid to minimize inflammatory response in elective cardiopulmonary bypass patients: a randomized double-blind, dose-dependent, phase IV clinical trial

Background. In cardiopulmonary bypass (CPB) patients, fibrinolysis may enhance postoperative inflammatory response. We aimed to determine whether an additional postoperative dose of antifibrinolytic tranexamic acid (TA) reduced CPB-mediated inflammatory response (IR). Methods. We performed a randomized, double-blind, dose-dependent, parallel-groups study of elective CPB patients receiving TA. Patients were randomly assigned to either the single-dose group (40 mg/Kg TA before CPB and placebo after CPB) or the double-dose group (40 mg/Kg TA before and after CPB). Results. 160 patients were included, 80 in each group. The incident rate of IR was significantly lower in the double-dose-group TA2 (7.5% vs. 18.8% in the single-dose group TA1; P = 0.030). After adjusting for hypertension, total protamine dose and temperature after CPB, TA2 showed a lower risk of IR compared with TA1 [OR: 0.29 (95% CI: 0.10-0.83), (P = 0.013)]. Relative risk for IR was 2.5 for TA1 (95% CI: 1.02 to 6.12). The double-dose group had significantly lower chest tube bleeding at 24 hours [671 (95% CI 549-793 vs. 826 (95% CI 704-949) mL; P = 0.01 corrected-P significant] and lower D-dimer levels at 24 hours [489 (95% CI 437-540) vs. 621(95% CI: 563-679) ng/mL; P = 0.01 corrected-P significant]. TA2 required lower levels of norepinephrine at 24 h [0.06 (95% CI: 0.03-0.09) vs. 0.20(95 CI: 0.05-0.35) after adjusting for dobutamine [F = 6.6; P = 0.014 corrected-P significant]. We found a significant direct relationship between IL-6 and temperature (rho = 0.26; P < 0.01), D-dimer (rho = 0.24; P < 0.01), norepinephrine (rho = 0.33; P < 0.01), troponin I (rho = 0.37; P < 0.01), Creatine-Kinase (rho = 0.37; P < 0.01), Creatine Kinase-MB (rho = 0.33; P < 0.01) and lactic acid (rho = 0.46; P < 0.01) at ICU arrival. Two patients (1.3%) had seizure, 3 patients (1.9%) had stroke, 14 (8.8%) had acute kidney failure, 7 (4.4%) needed dialysis, 3 (1.9%) suffered myocardial infarction and 9 (5.6%) patients died. We found no significant differences between groups regarding these events. Conclusions. Prolonged inhibition of fibrinolysis, using an additional postoperative dose of tranexamic acid reduces inflammatory response and postoperative bleeding (but not transfusion requirements) in CPB patients. A question which remains unanswered is whether the dose used was ideal in terms of safety, but not in terms of effectiveness.

Relative adrenal insufficiency and hemodynamic status in cardiopulmonary bypass surgery patients. A prospective cohort study

BACKGROUND: The objectives of this study were to determine the risk factors for relative adrenal insufficiency in cardiopulmonary bypass patients and the impact on postoperative vasopressor requirements. METHODS: Prospective cohort study on cardiopulmonary bypass patients who received etomidate or not during anesthetic induction. Relative adrenal insufficiency was defined as a rise in serum cortisol cardiopulmonary bypass patients were included. Relative adrenal insufficiency (Deltacortisol cardiopulmonary bypass patients may induce postoperative vasopressor dependency. Use of etomidate in these patients is a modifiable risk factor for the development of relative adrenal insufficiency that should be avoided.

Caval collapse during cardiopulmonary bypass: a reproducible bench model.

OBJECTIVES: During open heart surgery, so-called atrial chatter, a phenomenon due to right atria and/or caval collapse, is frequently observed. Collapse of the cava axis during cardiopulmonary bypass (CPB) limits venous drainage and may result downstream in reduced pump flow on (lack of volume) and upstream in increased after-load (stagnation), which in turn may both result in reduced or even inadequate end-organ perfusion. The goal of this study was to reproduce venous collapse in the flow bench. METHODS: In accordance with literature for venous anatomy, a caval tree system is designed (polyethylene, thickness 0.061 mm), which receives venous inflow from nine afferent veins. With water as medium and a preload of 4.4 mmHg, the system has an outflow of 4500 ml/min (Scenario A). After the insertion of a percutaneous venous cannula (23-Fr), the venous model is continuously served by the afferent branches in a venous test bench and venous drainage is augmented with a centrifugal pump (Scenario B). RESULTS: With gravity drainage (siphon: A), spontaneously reversible atrial chatter can be generated in reproducible fashion. Slight reduction in the outflow diameter allows for generation of continuous flow. With augmentation (B), irreversible collapse of the artificial vena cava occurs in reproducible fashion at a given pump speed of 2300 ± 50 RPM and a pump inlet pressure of -112 mmHg. Furthermore, bubbles form at the cannula tip despite the fact that the entire system is immersed in water and air from the environment cannot enter the system. This phenomenon is also known as cavitation and should be avoided because of local damage of both formed blood elements and endothelium, as well embolization. CONCLUSIONS: This caval model provides a realistic picture for the limitations of flow due to spontaneously reversible atrial chatter vs irreversible venous collapse for a given negative pressure during CPB. Temporary interruption of negative pressure in the venous line can allow for recovery of venous drainage. This know-how can be used not only for testing different cannula designs, but also for further optimizing perfusion strategies.

Validation of rotational thromboelastometry during cardiopulmonary bypass : a prospective, observational in-vivo study

Le ROTEM est un test de coagulation réalisable au près du malade qui permet d'objectiver la coagulopathie, de distinguer la contribution des différents éléments du système de coagulation et de cibler les produits procoagulants comme le plasma frais congelé (PFC), les plaquettes, le fibrinogène et les facteurs de coagulation purifiés ou les antifibrinolytiques. 3 des tests disponibles pour le ROTEM sont: EXTEM, INTEM, HEPTEM. Le premier test est stable sous hautes doses d'héparine alors que le deuxième est très sensible à sa présence. Dans le dernier test on rajoute de l'héparinase pour mettre en évidence l'éventuel effet résiduel de l'héparine en le comparant à l'INTEM. Idéalement, le ROTEM devrait être effectué avant la fin du bypass cardiopulmonaire (CEC), donc sous anticoagulation maximale pas héparine, afin de pouvoir administrer des produits pro¬coagulants dans les délais les plus brefs et ainsi limiter au maximum les pertes sanguines. En effet la commande et la préparation de certains produits procoagulants peut prendre plus d'une heure. Le but de cette étude est de valider l'utilisation du ROTEM en présence de hautes concentrations d'héparine. Il s'agit d'une étude observationnelle prospective sur 20 patients opérés électivement de pontages aorto-coronariens sous CEC. Méthode : l'analyse ROTEM a été réalisée avant l'administration d'héparine (TO), 10 minutes après l'administration d'héparine (Tl), à la fin de la CEC (T2) et 10 minutes après la neutralisation de l'anticoagulation avec la protamine (T3). L'état.d'héparinisation a été évalué par l'activité anti-Xa à T1,T2,T3. Résultats : Comparé à TO, la phase de polymérisation de la cascade de coagulation et l'interaction fibrine-plaquettes sont significativement détériorées par rapport à Tl pour les canaux EXTEM et HEPTEM. A T2 l'analyse EXTEM et INTEM sont comparables à celles de EXTEM et HEPTEM à T3. Conclusion: les hautes doses d'héparine utilisées induisent une coagulopathie qui reste stable durant toute la durée de la CEC et qui persiste même après la neutralisation de l'anticoagulation. Les mesures EXTEM et HEPTEM sont donc valides en présence de hautes concentrations d'héparine et peuvent être réalisés pendant la CEC avant l'administration de protamine.