Uncovering the (un-)occupied electronic structure of a buried hybrid interface.

The energy level alignment at organic/inorganic (o/i) semiconductor interfaces is crucial for any light-emitting or -harvesting functionality. Essential is the access to both occupied and unoccupied electronic states directly at the interface, which is often deeply buried underneath thick organic films and challenging to characterize. We use several complementary experimental techniques to determine the electronic structure of p -quinquephenyl pyridine (5P-Py) adsorbed on ZnO(1 0 -1 0). The parent anchoring group, pyridine, significantly lowers the work function by up to 2.9 eV and causes an occupied in-gap state (IGS) directly below the Fermi level E F. Adsorption of upright-standing 5P-Py also leads to a strong work function reduction of up to 2.1 eV and to a similar IGS. The latter is then used as an initial state for the transient population of three normally unoccupied molecular levels through optical excitation and, due to its localization right at the o/i interface, provides interfacial sensitivity, even for thick 5P-Py films. We observe two final states above the vacuum level and one bound state at around 2 eV above E F, which we attribute to the 5P-Py LUMO. By the separate study of anchoring group and organic dye combined with the exploitation of the occupied IGS for selective interfacial photoexcitation, this work provides a new pathway for characterizing the electronic structure at buried o/i interfaces.

Multiple organ failure after mitral valve repair with intravascular hemolysis and its recovery due to mitral valve replacement.

We present a patient with evidence of severe intravascular hemolysis after mitral valve repair, an established method for the surgical treatment of mitral valve disease to avoid prosthesis related complications. The coincidence of this uncommon complication with hemodynamic instability due to pre-existing myocardial dysfunction and Gram-negative pneumonia promoted the development of simultaneous dysfunction of liver, kidney and the cardio-respiratory system. Elimination of the source of hemolysis by re-operation with mitral valve replacement on the ninth postoperative day allowed prompt recovery from severe organ dysfunction. Free hemoglobin may have perpetuated progressive organ failure in our patient.

Polyneuropathies in critically ill patients: a prospective evaluation.

OBJECTIVE: To determine the incidence, severity and course of polyneuropathies in patients with sepsis or systemic inflammatory response syndrome combined with multiple organ failure. DESIGN: Prospective study. SETTING: Division of Intensive Care Medicine of the Department of Anesthesiology and Intensive Care and Intensive Care Unit of the Department of Neurology, University Hospital Innsbruck, Austria. PATIENTS: Twenty-two patients between 23 and 77 years old with sepsis or systemic inflammatory response syndrome combined with multiple organ failure fulfilling strict inclusion and exclusion criteria. INTERVENTIONS: Clinical neurologic examination and electro myography/nerve conduction velocity measurements during the stay on the Intensive Care Unit and 2-3 months later. MEASUREMENTS AND RESULTS: In 9 of the 22 patients signs of polyneuropathy were found at the initial clinical investigation and in 7 patients at the follow-up investigation. Electrophysiologic investigation revealed signs of polyneuropathy in 18 patients initially and in 11 patients 2-3 months later. CONCLUSION: In our patient population the frequency of the development of polyneuropathy was high (81.8%). Electrophysiologic investigation is superior to clinical neurologic examination in the detection of polyneuropathies.

Successful treatment of severe myocardial failure after postpartum haemorrhage with the use of an intra-aortic balloon pump.

We report a 29-year-old primigravid who developed cardiac failure following postpartum haemorrhage unresponsive to volume resuscitation and therapy with catecholamines and phosphodiesterase-inhibitors. Transoesophageal echocardiography (TEE) demonstrated left atrial and ventricular dilatation and global left ventricular hypokinesis. No elevation of serum MB-isoenzyme fraction was detected and other organ functions remained stable. Although emergency cardiac transplantation was considered in the presented patient, the institution of intra-aortic counterpulsation was decided on as a first treatment option. Intra-aortic balloon counter-pulsation rapidly improved cardiac function and led to weaning from pharmacological cardiac support within a few days. Mechanical circulatory assist devices can be life-saving in postpartum-haemorrhage-associated cardiac failure.

Tachyarrhythmias in a surgical intensive care unit: a case-controlled epidemiologic study.

OBJECTIVE: Incidence, types, and factors associated with new onset tachyarrhythmias (TA) in surgical intensive care patients. DESIGN: Pairwise-matched case-controlled study. SETTING: Surgical intensive care unit (ICU) with nine intensive care beds. PATIENTS: During a 1-year period, all TA patients (n = 89) were included in the study. Control patients (n = 82) without TA were matched according to age, sex, and surgical region. METHODS: TA workup included: 12-lead ECG, arterial blood gas, serum electrolyte (K+, Mg2+), and serum CK/CKMB isoenzyme analysis. Pre-existing cardiovascular and pulmonary disease, cardiovascular risk factors, preoperative regular medication, and admission SAPS were recorded in all patients. A multiple organ dysfunction syndrome (MODS) score, the presence or absence of SIRS or sepsis, and hemodynamics (MAP and CVP) before onset of TA were evaluated in TA patients, while in control patients highest MODS-score, the presence or absence of SIRS or sepsis, mean hemodynamic and laboratory values calculated from highest and lowest readings during ICU stay were used for statistical comparison. Logistic regression analysis was performed to identify variables multivariately associated with TA. RESULTS: Eighty-nine (14.8%) of 596 patients developed TA. Atrial fibrillation was most frequent (60.7%). Presence of SIRS or sepsis (adj. OR = 36.45; 95% CI: 11.5-115.5), high admission SAPS (adj. OR = 1.25/point; 95% CI: 1.08-1.44), high CVP (adj. OR = 1.27/mmHg; 95% CI: 1.09-1.48), and low arterial oxygen tension (adj. OR = 0.97/mmHg); 95% CI: 0.95-0.99) were found to be significant predictors for development of TA. CONCLUSIONS: In surgical patients hypoxia, high cardiac filling pressures, a greater degree of physiologic derangement at admission, and the presence of SIRS and sepsis are independent risk factors for the development of TA.

Cardiac performance during vasopressin infusion in postcardiotomy shock.

OBJECTIVE: Arginine-vasopressin (AVP) might be a potent vasopressor agent in catecholamine-resistant postcardiotomy shock. However, its use remains experimental because of considerations about deleterious effects on the heart. We report on the effects of continuous AVP-infusion on cardiac performance, biomarkers of myocardial ischemia, and systemic hemodynamics in catecholamine-resistant postcardiotomy shock. DESIGN: Retrospective study. SETTING: Twenty-one-bed general and surgical intensive care unit. PATIENTS: Forty-one patients with catecholamine-resistant postcardiotomy shock. INTERVENTIONS: Continuous infusion of AVP. MEASUREMENTS AND RESULTS: Heart rate (HR), heart rhythm, mean arterial pressure (MAP), central venous pressure, mean pulmonary arterial pressure, cardiac index (CI), stroke volume index (SVI), left ventricular stroke work index (LVSWI), systemic vascular resistance (SVR) as well as milrinone and norepinephrine requirements were collected before and 1, 4, 12, 24, and 48 h after start of AVP infusion. Creatine kinase MB and troponin-I serum concentrations were measured daily. During AVP administration we observed a significant decrease in HR (-14.8%), milrinone (-17.5%), and norepinephrine requirements (-54.9%) as well as biomarkers of cardiac ischemia and a significant increase in LVSWI (+46.2%), MAP (+41.8%) and SVR (+60%). CI and SVI remained unchanged. Forty-five percent of postoperative new-onset tachyarrhythmias (TA) converted into sinus rhythm during AVP infusion. CONCLUSIONS: AVP was devoid of adverse effects on the heart in these patients with catecholamine-resistant postcardiotomy shock. The significant reduction in HR, vasopressor, and inotropic support suggest a substantial improvement in myocardial performance. These findings are supported by a significant decrease of cardiac enzymes and cardioversion of TA into sinus rhythm in 45.5% of patients with new-onset TA.

[Assessment of the cardiac output by impedance cardiography (differential rheography) to give optimum continuous positive pressure ventilation (author's transl)]. / Beurteilung des Herzzeitvolumens durch Impedanzmessung (Differentialrheographie) zur Optimierung der kontinuierlichen Uberdruckbeatmung (CPPV).

It is very important to know the cardiac output in artificial positive pressure ventilation for the determination of the exact dosage of dopamine and the endexpiratory pressure. Invasive monitoring of the cardiac output is not suitable for routine bedside use. In our study we looked into the question of whether the dosage of dopamine in continuous positive pressure ventilation could be controlled by impedance determination. Differential rheography, as described by Kaindl, Polzer, and Schuhfried, was used in the study. Relative changes in cardiac output after dopamine administration are shown with sufficient accuracy using the above-mentioned method.

[High-frequency ventilation. Development of new ventilation systems--experimental and clinical results]. / Hochfrequenzbeatmung. Entwicklung neuer Beatmungssysteme--experimentelle und klinische Ergebnisse.

Based on the well known High Frequency Jet Ventilation (HFJV) two modified types of High Frequency Ventilation, Forced Diffusion Ventilation (FDV) and High Frequency Pulsation (HFP) have been developed. Both systems are designed to allow ventilation with very small volume portions in the upper range of HFV frequencies. In dog experiments sufficient gas exchange could be maintained during FDV up to frequencies 3000 per minute and even with an uninterrupted "continuous" jet entering the lungs on carina level. With this mode of ventilation lung could be kept in a resting position. Due to particular configuration of a pair of nozzles at the tip of a modified endotracheal catheter fresh gas is forced down the airways along the inner edges of bifurcations towards the lung periphery. At the same time stale gas leaves the lung via the remaining cross section of the airways. Thus a continuous scavanging process can be established without significant lung inflation. This mechanisms are not met during HFP. Therefore the range of frequencies achievable with this type of ventilation is significantly lower (250 to 500/min.) and "tidal volumes" are much higher. However, they are still beyond the anatomical dead space which suggest again a contribution of alternative mechanisms to gas transport. The impact of both types of HFV on gas exchange and pressure-flow conditions were studied in lung models as well as in animal experiments. FDV and HFP were also applied successfully to a group of 23 patients undergoing major lung surgery. In all patients it was possible to maintain excellent gas exchange throughout the whole surgical procedure. The exposure of the surgical field was much more quiet as compared to IPPV. Due to the small tidal volumes lung pressures can be kept much lower and gas losses via the open bronchi and lung surface are reduced dramatically.

[Modification of patients positions in operation table during regional anaesthesia (author's transl)]. / Modifikationen der Lagerung bei Patienten unter Regionalanästhesie (Plexus-axillaris-Blockade).

The comfort was improved by better positioning on the operating table in six patients undergoing extensive hand surgery with axillary plexus block. Opposite to that we could show in 16 similar cases with traditional position during surgery some pain, chills and discomfort despite optimal block technique.

[The behavior of free thyroxine and triiodothyronine concentrations after short-term balanced inhalation anesthesia]. / Das Verhalten der freien Thyroxin- und Trijodthyronin-Serumkonzentrationen nach kurzandauernden balancierten Inhalationsnarkosen.

Acute changes involving the hormones thyroxine (T4) and triiodothyronine (T3) followed by hyper -or hypothyroid crises will lead to both cardiovascular and metabolic disorders. Due to highly sensitive mechanisms controlling central hormonal production and peripheral enzymatic conversion (c.g. T4 to T3), numerous pharmacologically effective substances will influence the kinetics of these hormones. Thus, agents routinely used in anesthetic practice and their metabolites may disturb hormonal regulation in particular due to their central effectiveness [1, 2,5-7]. Based on this premise, it was our goal to search for anesthetic-induced hormonal changes in euthyroid patients living in a goiter-endemic area scheduled for short, elective orthopedic operations. Investigations were done in 21 outpatients (mean age: 24 years, mean body wt.: 64 kg) undergoing minor surgical procedures of the extremities. No clinical signs of thyroid disturbances could be observed preoperatively in the patients. Immediately after intravenous premedication (meperidine HCl 0.75 mg/kg and atropine 0.25 mg), anesthesia was induced (thiopentone 5 mg/kg) and continued by inhalation via face; mask using volatile agents: halothane, isoflurane, or enflurane (O2: N2O; FiO2 = 0.33). According to the anesthetic agent administered (halothane, isoflurane, enflurane), patients were divided into three groups of 7 patients each as listed in Table 1. Blood samples to determine free serum T4 (fT4) and T3 (fT3) as an expression of biologically available T4/T3, unconjugated to transport globulins, were drawn twice: immediately before premedication; and postoperatively after the patient had regained consciousness.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of end-expiratory lung volume on carbon dioxide elimination during high frequency ventilation in dogs.

We have examined the effect of varying end-expiratory lung volume on carbon dioxide elimination in 10 mongrel dogs undergoing conventional mechanical ventilation at 12 b.p.m. and forced diffusion ventilation (FDV) at 6 Hz and 50 Hz and continuous flow. End-expiratory volumes were altered by changing the pressure in a plethysmographic box in which the dogs underwent ventilation. The pressures studied were atmospheric, sub-atmospheric (box pressure -1.0 kPa) and increased atmospheric (box pressure + 0.5 kPa). The results indicated that more carbon dioxide was eliminated at low lung volumes and this was most pronounced with HFV at 50 Hz and continuous flow. It is postulated that changes in airway geometry and different lung volumes may alter the distance between the gas interface in the conductive airways and the respiratory zone and so alter the efficiency of ventilation during FDV.

[Experiences using the suction curettage system of Hamann and Pockrand (author's transl)]. / Erfahrungen mit dem Saugkürettensystem nach Hamann und Pockrandt.

All curettages of a 8-week-period were done using the suction system of Hamann and Pockrandt. This test-collective includes 66 patients, their age was between 20 and 78 years; 6 of them had to be excluded: the surgical intervention was begun without general anaesthesia but continued with general anaesthesia is required by the patient. The test-collective was divided into 2 groups: in group A (30 patients) all suction-curettages were done in general anaesthesia, in the first 20 patients a conventional curettage with dilation of the cervix were performed additionally, in order to proof the effectiveness of the suction curettage. The histological findings of the materials of the conventional curettages had shown no more informations than that of the materials of the suction curettages. -- In group B (30 patients) the suction curettage were done in diazepampentazocin-analgesia; a third of them had specified no sensations, the others had stated a feeling of pressure or spasms. -- In each group the histological examinations were possible without any problems. The advantages of the suction curettage system are the rare necessity of cervix dilatation (7 of 60 cases), the possibility of the operation without general anaesthesia and the possibility of a quick performance of the curettage.

[Home-respirator treatment in idiopathic hypoventilation (author's transl)]. / Heimrespiratorbehandlung bei idiopathischer Hypoventilation.

A report is given on a 66 years old patient with severe idiopathic hypoventilation. Two years ago the disease had developed rather suddenly with severe hypoventilation during sleep, accompanied by marked hypoxemia and hypercapnia with pCO2-values above 100mm Hg and respiratory acidosis. No pulmonary, cardiac or neurological disease was found. After failure of two attempts of stimulation of the phrenic nerve the patient was admitted to a respiratory intensive care unit and ventilated by a respirator during sleep. After improvement of this general condition he was discharged at first only in the daytime, later he could be discharged fully from the unit, after a respirator had been installed in his home. Now the patient is connecting himself to the respirator during sleep and since 20 months is so in a tolerable condition. The indications for home-respirator treatment are discussed.

[Continuous arteriovenous hemofiltration in interstitial pulmonary edema]. / Kontinuierliche arteriovenöse Hämofiltration beim interstitiellen Lungenödem.

In a retrospective study 40 ICU patients, all underwent Continuous Arteriovenous Hemofiltration (CAVH) for acute pulmonary, acute renal insufficiency or both, were evaluated for lung function parameters and fluid balance. It could be shown that a group of patients suffering from pulmonary insufficiency and with a history of major trauma or obstetric complications mainly benefits from fluid control by means of CAVH, while diuretics were unable to perform the desired action.

[Effect of arm splinting on the duration and possibility of monitoring invasive long-term pressure determination of the radial artery]. / Einfluss der Armschienung auf Verweildauer und Monitierbarkeit bei blutiger arterieller Langzeitdruckmessung über die A. radialis.

A special splint technique, which can improve continuous intraarterial blood pressure monitoring via the a. radialis is reported. This method could be applied successfully in 41 patients of the ICU up to 27 days. Cannulating the contralateral side because of catheter's dysfunction was necessary only in 6 patients. These observations could be seen in contrast to our results, using a conventional splint system, applied in 12 patients for comparison (maximal duration of catheter's placement: 9 days). Our experiences, using this special splint method of arm fixation, lead to the recommendation to use our method routinely in long-term monitored patients, with respect to a longer duration of catheter's intravasal placement, the possibility of undisturbed monitoring and a simple clinical handling.