Michael Winterhalter

Bleeding management with fibrinogen concentrate targeting a high-normal plasma fibrinogen level: a pilot study

Background Bleeding diathesis after aortic valve operation and ascending aorta replacement (AV–AA) is managed with fresh-frozen plasma (FFP) and platelet concentrates. The aim was to compare haemostatic effects of conventional transfusion management and FIBTEM (thromboelastometry test)-guided fibrinogen concentrate administration. Methods A blood products transfusion algorithm was developed using retrospective data from 42 elective patients (Group A). Two units of platelet concentrate were transfused after cardiopulmonary bypass, followed by 4 u of FFP if bleeding persisted, if platelet count was ≤100×103 µl−1 when removing the aortic clamp, and vice versa if platelet count was >100×103 µl−1. The trigger for each therapy step was ≥60 g blood absorbed from the mediastinal wound area by dry swabs in 5 min. Assignment to two prospective groups was neither randomized nor blinded; Group B (n=5) was treated according to the algorithm, Group C (n=10) received fibrinogen concentrate (Haemocomplettan® P/Riastap, CSL Behring, Marburg, Germany) before the algorithm-based therapy. Results A mean of 5.7 (0.7) g fibrinogen concentrate decreased blood loss to below the transfusion trigger level in all Group C patients. Group C had reduced transfusion [mean 0.7 (range 0–4) u vs 8.5 (5.3) in Group A and 8.2 (2.3) in Group B] and reduced postoperative bleeding [366 (199) ml vs 793 (560) in Group A and 716 (219) in Group B]. Conclusions In this pilot study, FIBTEM-guided fibrinogen concentrate administration was associated with reduced transfusion requirements and 24 h postoperative bleeding in patients undergoing AV–AA.

Thromboelastometry-guided administration of fibrinogen concentrate for the treatment of excessive intraoperative bleeding in thoracoabdominal aortic aneurysm surgery

OBJECTIVE Thoracoabdominal aortic aneurysm operations are associated with extensive blood loss and high requirements for allogeneic blood product transfusion. We assessed the efficacy of intraoperative post-cardiopulmonary bypass administration of fibrinogen concentrate in elective thoracoabdominal aortic aneurysm surgery. METHODS In a retrospective group (group A, n = 12) of patients undergoing elective thoracoabdominal aortic aneurysm surgery, clinically relevant diffuse bleeding after weaning from cardiopulmonary bypass was treated with allogeneic blood products (platelet concentrates, followed by fresh frozen plasma) according to a predetermined algorithm. In a prospective group (group F, n = 6) a first therapy step with fibrinogen concentrate was added to the algorithm. The dose of fibrinogen concentrate was estimated by using thromboelastometric data (ROTEM FIBTEM). Before each step of hemostatic therapy, blood loss in the range of 60 to 250 g per 5 minutes was confirmed. RESULTS In group F, administration of 7.8 +/- 2.7 g of fibrinogen concentrate established hemostasis, completely avoiding intraoperative transfusion of fresh frozen plasma and platelet concentrates. Transfusion of blood products after cardiopulmonary bypass and during the 24 hours after surgical intervention was markedly lower in group F than in group A (2.5 vs 16.4 units; 4/6 patients in group F required no transfusion of blood products), as was 24-hour drainage volume (449 vs 1092 mL). Fibrinogen plasma levels, standard coagulation parameters, and hemoglobin and hematocrit values were comparable between the 2 groups on the first postoperative day. CONCLUSIONS FIBTEM-guided post-cardiopulmonary bypass administration of fibrinogen concentrate resulted in improved intraoperative management of coagulopathic bleeding in thoracoabdominal aortic aneurysm operations and reduced transfusion and 24-hour drainage volume.

Hypothermic circulatory arrest with selective antegrade cerebral perfusion in ascending aortic and aortic arch surgery: A risk factor analysis for adverse outcome in 501 patients

OBJECTIVE This study was undertaken to identify preoperative and intraoperative risk factors influencing outcome after operations requiring hypothermic circulatory arrest with selective antegrade cerebral perfusion in a single center. METHODS Between November 1999 and March 2006, a total of 501 consecutive patients (median age 64 years, range 20-86 years, 320 male) underwent aortic arch surgery with moderate hypothermic circulatory arrest (25 degrees C +/- 2 degrees C) and additional selective antegrade cerebral perfusion (14 degrees C) at our institution for various indications (256 aneurysms, 153 acute and 23 chronic type A aortic dissections, 66 other). Of these, 181 were emergency operations. Statistical analysis was carried out to determine risk factors for 30-day mortality as well as for temporary and permanent neurologic dysfunction. RESULTS Overall mortality was 11.6%. Permanent neurologic dysfunction occurred in 48 patients (9.6%); temporary neurologic dysfunction was detected in 67 patients (13.4%). Multivariate analysis revealed age (P = .001, odds ratio 1.08), reoperation (P = .006, odds ratio 3.58), femoral arterial cannulation (P = .004, odds ratio 2.87), and cardiopulmonary bypass duration (P < .001, odds ratio 1.009) as risk factors for mortality. Permanent neurologic dysfunction was associated with preoperative renal insufficiency (P = .029, odds ratio 2.79) and operation time (P < .001, odds ratio 1.005), whereas temporary neurologic dysfunction occurred in patients with coronary artery disease (P = .04, odds ratio 2.29), emergency surgery (P = .001, odds ratio 4.09), and increasing hypothermic circulatory arrest duration (P = .01, odds ratio 1.015). CONCLUSION Moderate hypothermic circulatory arrest in combination with cold selective antegrade cerebral perfusion is an adequate tool for neuroprotection during aortic surgery. Nevertheless, the safety of this technique is limited for patients with long intraoperative durations, advanced age, and multiple comorbidities. This technique, which avoids profound core temperatures, has become an alternative to simple deep hypothermic circulatory arrest.

Auricular acupuncture for dental anxiety: a randomized controlled trial.

Auricular acupuncture can be an effective treatment for acute anxiety, but there is a lack of direct comparisons of acupuncture to proven standard drug treatments. In this study we compared the efficacy of auricular acupuncture with intranasal midazolam, placebo acupuncture, and no treatment for reducing dental anxiety. Patients having dental extractions (n = 67) were randomized to (i) auricular acupuncture, (ii) placebo acupuncture, and (iii) intranasal midazolam and compared with a no treatment group. Anxiety was assessed before the interventions, at 30 min, and after the dental extraction. Physiological variables were assessed continuously. With the no treatment group as control, the auricular acupuncture group, and the midazolam group were significantly less anxious at 30 min as compared with patients in the placebo acupuncture group (Spielberger Stait-Trait Anxiety Inventory X1, P = 0.012 and <0.001, respectively). In addition, patient compliance assessed by the dentist was significantly improved if auricular acupuncture or application of intranasal midazolam had been performed (P = 0.032 and 0.049, respectively). In conclusion, both, auricular acupuncture and intranasal midazolam were similarly effective for the treatment of dental anxiety.

Comparison of inhaled iloprost and nitric oxide in patients with pulmonary hypertension during weaning from cardiopulmonary bypass in cardiac surgery: a prospective randomized trial.

OBJECTIVE The objective of this study was to compare the efficacy of inhaled iloprost and nitric oxide (iNO) in reducing pulmonary hypertension (PHT) during cardiac surgery immediately after weaning from cardiopulmonary bypass (CPB). DESIGN A prospective randomized study. SETTING A single-center university hospital. PARTICIPANTS Forty-six patients with PHT (mean pulmonary artery pressure (mPAP) > or = 26 mmHg preoperatively at rest, after anesthesia induction, and at the end of CPB) scheduled to undergo cardiac surgery were enrolled. INTERVENTIONS Patients were randomly allocated to receive iloprost (group A, n = 23) or iNO (group B, n = 23) during weaning from CPB. MEASUREMENTS AND MAIN RESULTS Heart rate, mean arterial pressure, central venous pressure, pulmonary artery pressure (PAP), pulmonary capillary wedge pressure, and left atrial pressure were recorded continuously. Iloprost and iNO were administered immediately after the end of CPB before heparin reversal. Both substances caused significant reductions in mean PAP (mPAP) and pulmonary vascular resistance (PVR) and significant increases in cardiac output 30 minutes after administration (p < 0.0001). However, in a direct comparison, iloprost caused significantly greater reductions in PVR (p = 0.013) and mPAP (p = 0.0006) and a significantly greater increase in cardiac output (p = 0.002) compared with iNO. CONCLUSIONS PHT after weaning from CPB was significantly reduced by the selective pulmonary vasodilators iNO and iloprost. However, in a direct comparison of the 2 substances, iloprost was found to be significantly more effective.

Hypothermic circulatory arrest during ascending and aortic arch surgery: the theoretical impact of different cerebral perfusion techniques and other methods of cerebral protection.

Operations on the thoracic aorta using hypothermic circulatory arrest are still associated with significant morbidity and mortality due to neurological complications. During the last decades, different cerebral protection techniques have been introduced into clinical practice to reduce the incidence of such complications. Furthermore clinical as well as basic researches have been performed to improve the outcome after these operations. Currently different cerebral perfusion methods are in clinical use and the superiority of one or the other method is a matter of controversial discussion. This review has been undertaken to evaluate the theoretical impact of these different methods of cerebral protection. Based on the experience of the authors the pros and cons are discussed with clinical and experimental reports from the literature.

Endocrine stress response and inflammatory activation during CABG surgery. A randomized trial comparing remifentanil infusion to intermittent fentanyl

Background and objective: Our aim was to compare a continuous infusion of remifentanil with intermittent boluses of fentanyl as regards the perioperative hormonal stress response and inflammatory activation in coronary artery bypass graft patients under sevoflurane‐based anaesthesia. Methods: In all, 42 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to a fentanyl group (n = 21, total fentanyl dose 2.6 ± 0.3 mg), or a remifentanil group (n = 21, infusion rate 0.25 &mgr;g kg−1 min−1). Haemodynamics, plasma levels of epinephrine, norepinephrine, antidiuretic hormone, adrenocorticotropic hormone, cortisol, complement activation (C3a, C5b‐9), interleukin (IL)‐6, IL‐8 and tumour necrosis factor‐&agr; were measured at T1: baseline, T2: intubation, T3: sternotomy, T4: 30 min on cardiopulmonary bypass, T5: end of surgery and T6: 8 h postoperatively. Troponin T and creatine kinase‐MB were measured postoperatively. Results: Patients in the remifentanil group were extubated significantly earlier than fentanyl patients (240 ± 182 min vs. 418 ± 212 min, P = 0.006). Stress hormones 30 min after start of cardiopulmonary bypass showed higher values in the fentanyl group compared to the remifentanil group (antidiuretic hormone (ADH): 39.94 ± 30.98 vs. 11.7 ± 22.8 pg mL−1, P = 0.002; adrenocorticotropic hormone: 111.5 ± 116.8 vs. 21.81 ± 24.71 pg mL−1, P = 0.01; cortisol 185 ± 86 vs. 131 ± 82 ng mL−1, P = 0.04). The interleukins were significantly higher at some perioperative time points in the fentanyl group compared to the remifentanil group (tumour necrosis factor: T5: 3.57 vs. 2.37; IL‐6: T5: 4.62 vs. 3.73; and IL‐8: T5: 4.43 vs. 2.65 and T6: 2.61 vs. 1.13). However, cardiopulmonary bypass times and aortic cross‐clamp times were longer in the fentanyl group, which may to some extent account for the differences. Conclusions: The perioperative endocrine stress response was attenuated in patients supplemented with continuous remifentanil infusion as compared to intermittent fentanyl.

In vivo myograph measurement of muscle contraction at optimal length

BackgroundCurrent devices for measuring muscle contraction in vivo have limited accuracy in establishing and re-establishing the optimum muscle length. They are variable in the reproducibility to determine the muscle contraction at this length, and often do not maintain precise conditions during the examination. Consequently, for clinical testing only semi-quantitative methods have been used.MethodsWe present a newly developed myograph, an accurate measuring device for muscle contraction, consisting of three elements. Firstly, an element for adjusting the axle of the device and the physiological axis of muscle contraction; secondly, an element to accurately position and reposition the extremity of the muscle; and thirdly, an element for the progressive pre-stretching and isometric locking of the target muscle.Thus it is possible to examine individual in vivo muscles in every pre-stretched, specified position, to maintain constant muscle-length conditions, and to accurately re-establish the conditions of the measurement process at later sessions.ResultsIn a sequence of experiments the force of contraction of the muscle at differing stretching lengths were recorded and the forces determined. The optimum muscle length for maximal force of contraction was established. In a following sequence of experiments with smaller graduations around this optimal stretching length an increasingly accurate optimum muscle length for maximal force of contraction was determined. This optimum length was also accurately re-established at later sessions.ConclusionWe have introduced a new technical solution for valid, reproducible in vivo force measurements on every possible point of the stretching curve. Thus it should be possible to study the muscle contraction in vivo to the same level of accuracy as is achieved in tests with in vitro organ preparations.

Comparison of electrical velocimetry and transpulmonary thermodilution for measuring cardiac output in piglets

Background:  Monitoring of cardiovascular function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output (CO) and oxygen delivery is expensive and sometimes associated with adverse events. Therefore, we investigated the accuracy of a new noninvasive CO monitoring device using electrical velocimetry (EV) in comparison with the more invasive transpulmonary thermodilution (TPTD) method.

Hybrid Endograft for One-Step Treatment of Multisegment Disease of the Thoracic Aorta

PURPOSE At present, a two-step surgical approach is necessary to treat patients with coexistent pathologic conditions involving the proximal and descending thoracic aorta. A hybrid endograft is described here that enables such treatment during a single operation. MATERIALS AND METHODS The Chavan-Haverich endograft consists of a Dacron vascular prosthesis with stainless-steel stents affixed at its distal end. After approval by the institutional review board, the endograft was prospectively implanted in 22 patients with multisegment thoracic aortic disease (13 men, nine women; median age, 64 years). Eleven patients had type A dissections (one acute, 10 chronic), four had a chronic type B dissection, and seven had atherosclerotic aneurysms of the ascending aorta or aortic arch as well as of the descending aorta. Of these patients, 11 additionally required aortic valve replacement or coronary artery bypass grafting. Via median sternotomy, the aortic arch was opened in circulatory arrest. After antegrade deployment of the stent-containing portion in the descending aorta, the proximal non-stent-containing endograft was used to reconstruct the aortic arch. Median follow-up was 14 months. RESULTS Endograft implantation was successful in all but one patient. Complications included neurologic deficits that were transient in one case and lasting in two, two cases of vocal cord paralysis, and one death. In all patients with atherosclerotic aneurysms who received the endograft (six of seven), aneurysm thrombosis was noted at follow-up. In aortic dissections, partial or complete false-lumen thrombosis to the level of the stents occurred in all patients. None of the patients showed a progressive widening of the descending aorta. CONCLUSION The Chavan-Haverich endograft enables one-step treatment of multisegment pathologic conditions affecting the thoracic aorta that otherwise would require two or more operations.