Hybrid Procedure with Debranching from the Descending Aorta for Aortic Arch Aneurysm after Previous Open Repair.

Aortic arch aneurysms can be treated with hybrid procedures by endovascular exclusion and prior debranching of supra-aortic arteries. We report on a case of symptomatic arch aneurysm following previous supracoronary ascending aorta and hemiarch replacement with a very short proximal landing zone. A successful reconstruction was performed by retrograde revascularization of supra-aortic vessels from the descending aorta and subsequent endovascular repair deploying a proximal stent graft directly above the sinotubular junction with good results in the 4-year follow-up. Retrograde supra-aortic debranching may constitute a suitable approach for hybrid endovascular repair of aneurysms of the aortic arch and the ascending aorta in selected cases.

Catecholamine and volume therapy for cardiac surgery in Germany--results from a postal survey.

BACKGROUND: Management of cardiac surgery patients is a very standardized procedure in respective local institutions. Yet only very limited evidence exists concerning optimal indication, safety and efficacy of hemodynamic monitoring catecholamine and fluid therapy. METHODS: Between April and May 2013, all 81 German anaesthesia departments involved in cardiac surgery care were asked to participate in a questionnaire addressing the institutional specific current practice in hemodynamic monitoring, catecholamine and volume therapy. RESULTS: 51 (63%) questionnaires were completed and returned. All participating centers used basic hemodynamic monitoring (i.e. invasive arterial blood pressure and central venous pressure), supplemented by transesophageal echocardiography. Pulmonary arterial catheter and calibrated trend monitoring devices were also routinely available. In contrast, non-calibrated trend monitoring and esophageal doppler ultrasound devices were not commonly in use. Cerebral oximetry is increasingly emerging, but lacks clear indications. The majority of patients undergoing cardiac surgery, especially in university hospitals, required catecholamines during perioperative care, In case of low cardiac output syndrome, dobutamine (32%), epinephrine (30%) or phosphodiesterase inhibitors (8%) were first choice. In case of hypotension following vasoplegia, norepinephrine (96%) represented the most common catecholamine. 88% of the participating centers reported regular use of colloid fluids, with hydroxyethyl starches (HES) being first choice (64%). CONCLUSIONS: Choice of hemodynamic monitoring is homogenous throughout German centers treating cardiac surgery patients. Norepinephrine is the first line catecholamine in cases of decrease in peripheral vascular resistance. However, catecholamine choice for low cardiac output syndrome varies considerably. HES was the primary colloid used for fluid resuscitation. After conduct of this survey, HES use was restricted by European regulatory authorities in critically ill patients and should only be considered as second-line fluid in surgical patients without renal impairment or severe coagulopathy. Large clinical studies addressing catecholamine and fluid therapy in cardiac surgery patients are lacking.

Perioperative fluid therapy with tetrastarch and gelatin in cardiac surgery--a prospective sequential analysis*.

OBJECTIVES: To determine clinical outcomes of synthetic colloids, tetrastarch, and gelatin, used before and after cardiac surgery. DESIGN: Prospective observational cohort study. SETTING: Fifty-bed cardiac ICU. PATIENTS: Six thousand four hundred seventy-eight consecutive patients with cardiopulmonary bypass surgery. INTERVENTIONS: Fluid therapy in the operating room and on the ICU directed at preset hemodynamic goals: 1) hydroxyethyl starch (predominantly 6% hydroxyethyl starch 130/0.4) in 2004-2006, n = 2,137; 2) 4% gelatin in 2006-2008, n = 2,324; and 3) only crystalloids in 2008-2010, n = 2,017. MEASUREMENTS AND MAIN RESULTS: Renal replacement therapy was more common during periods when patients received synthetic colloids compared to only crystalloids. Risk of renal replacement therapy was greater after hydroxyethyl starch (odds ratio, 2.29; 95% CI, 1.47-3.60) and gelatin (odds ratio, 2.75; 95% CI, 1.84-4.16; both p < 0.001) compared to crystalloid. Propensity score stratification confirmed greater use of renal replacement therapy in the hydroxyethyl starch and gelatin periods compared to the crystalloid period (odds ratio, 1.46 [1.08, 1.97]; p = 0.013 and odds ratio, 1.72 [1.33, 2.24]; p < 0.001, respectively). Time to vasopressor cessation, normalization of serum lactate, and mean arterial pressure did not differ among groups. Total fluid requirement was 163 mL/kg in the hydroxyethyl starch period, 207 mL/kg in the gelatin period, and 224 mL/kg in the crystalloid period. Fluid intake was higher in the crystalloid group only during the first 20 hours. CONCLUSIONS: In cardiac surgery patients, fluid therapy with perioperative administration of synthetic colloids carries a high risk of renal replacement therapy and is not more effective than treating with only crystalloids.

Analysis and modeling of time-variant amplitude-frequency couplings of and between oscillations of EEG bursts.

Low-frequency (0.5-2.5 Hz) and individually defined high-frequency (7-11 or 8-12 Hz; 11-15 or 14-18 Hz) oscillatory components of the electroencephalogram (EEG) burst activity derived from thiopental-induced burst-suppression patterns (BSP) were investigated in seven sedated patients (17-26 years old) with severe head injury. The predominant high-frequency burst oscillations (>7 Hz) were detected for each patient by means of time-variant amplitude spectrum analysis. Thereafter, the instantaneous envelope (IE) and the instantaneous frequency (IF) were computed for these low- and high-frequency bands to quantify amplitude-frequency dependencies (envelope-envelope, envelope-frequency, and frequency-frequency correlations). Time-variant phase-locking, phase synchronization, and quadratic phase couplings are associated with the observed amplitude-frequency characteristics. Additionally, these time-variant analyses were carried out for modeled burst patterns. Coupled Duffing oscillators were adapted to each EEG burst and by means of these models data-based burst simulations were generated. Results are: (1) strong envelope-envelope correlations (IE courses) can be demonstrated; (2) it can be shown that a rise of the IE is associated with an increase of the IF (only for the frequency bands 0.5-2.5 and 7-11 or 8-12 Hz); (3) the rise characteristics of all individually averaged envelope-frequency courses (IE-IF) are strongly correlated; (4) for the 7-11 or 8-12 Hz oscillation these associations are weaker and the variation between the time courses of the patients is higher; (5) for both frequency ranges a quantitative amplitude-frequency dependency can be shown because higher IE peak maxima are accompanied by stronger IF changes; (6) the time range of significant phase-locking within the 7-11 or 8-12 Hz frequency bands and of the strongest quadratic phase couplings (between 0.5-2.5 and 7-11 or 8-12 Hz) is between 0 and 1,000 ms; (7) all phase coupling characteristics of the modeled bursts accord well with the corresponding characteristics of the measured EEG burst data. All amplitude-frequency dependencies and phase locking/coupling properties described here are known from and can be discussed using coupled Duffing oscillators which are characterized by autoresonance properties.

Increasing cardiac output by epinephrine after cardiac surgery: effects on indocyanine green plasma disappearance rate and splanchnic microcirculation.

OBJECTIVE: The effects of increasing cardiac output by epinephrine on indocyanine green plasma disappearance rate (ICG-PDR) and gastric mucosal PCO(2) (P(R)CO(2)) were studied as indicators of splanchnic microcirculation. DESIGN: A prospective clinical study. SETTING: Intensive care unit of a university hospital. PARTICIPANTS: With ethics approval and written consent, 12 elective cardiac surgical patients (5 female, 7 male, 71 +/- 8 years) were studied. INTERVENTIONS: Patients underwent pulmonary artery and left atrial catheterization for clinical indications. Measurements were made at intensive care unit admission and 1 hour after (increased) epinephrine treatment. Mean epinephrine dose was changed from 0.02 to 0.08 microg/kg/min. RESULTS: Heart rate significantly increased from 97 +/- 11 to 106 +/- 12 beat/min. Central venous (10 +/- 3 v 10 +/- 4 mmHg) and left atrial (10 +/- 5 v 11 +/- 5 mmHg) pressures were unchanged. Cardiac index and stroke volume index significantly increased from 2.7 +/- 0.5 to 3.2 +/- 0.5 L/min/m(2) and from 28 +/- 6 to 31 +/- 5 mL/m(2), respectively. Although systemic O(2) delivery and O(2) consumption significantly increased, ICG-PDR did not change significantly (ie, from 18.0% +/- 5.6% to 19.5% +/- 6.4% per minute). P(R)CO(2) and PCO(2) gap (difference between regional and end-tidal PCO(2)) significantly increased from 5.4 +/- 1.0 to 5.9 +/- 1.1 kPa and 1.2 +/- 0.8 to 1.5 +/- 0.7 kPa, respectively. CONCLUSION: Increasing cardiac output by epinephrine in patients after cardiac surgery was not associated with a change in flow-dependent liver function but a deterioration in gastric mucosal perfusion.

Case report: the malfunctioning implanted venous access device.

Totally implanted venous access devices (VADs) are an alternative to central line placement for those patients requiring frequent intravenous access. Venous thrombosis, infection, extrusion, extravasation and occlusion are commonly encountered complications of central VADS. Fracture with embolization of implantable venous access catheter is a rare complication of this commonly used device, but it may have serious consequences. Clinical manifestation may include infraclavicular or chest pain, paraesthesias in the arm, cardiac arrhythmias, palpitation or an extra heart sound, in addition to withdrawal occlusion, swelling, and resistance to infusion. Nursing staff should be aware of these signs and symptoms and they should immediately stop any infusion if these signs and symptoms emerge. Whenever problems with a VAD occur a chest radiograph or a contrast enhanced angiographic control of the VAD is advised. This article provides two cases relating to malfunction of a VAD. Despite typical symptoms in both cases a catheter fracture with embolization was not taken into consideration, and a radiological control of the VAD was not performed. It was only by chance that the patients did not sustain any harmful sequels from the broken VAD.

Time-variant investigation of quadratic phase couplings caused by amplitude modulation in electroencephalic burst-suppression patterns.

OBJECTIVE: Several studies suggest that parameters derived from bispectral analysis of the EEG can be used to characterize specific cortical activation states represented by non linear interaction between brain electrical oscillations. For example, it was shown that so-called bispectral indices can be used to assess the depth of sedation. The methods applied so far are based on interval-related procedures of bispectral analysis. Consequently, the use of the resulting parameters for on-line monitoring or investigations of signal properties during transition periods, e.g., when entering burst-suppression periods, is restricted. The objective of this paper is to provide the methodological basis for a time-continuous (on-line) investigation of quadratic phase coupling induced by amplitude modulation. METHODS: To accomplish this aim an algorithm is presented which enables the analysis of the temporal development in the degree of amplitude modulation (DAM), e.g., during the transition to burst-suppression periods in patients with severe neurological diseases. RESULTS: It was found that these periods are associated with increasing DAM compared with the baseline conditions.