[Laudation for university professor Dr. med. Konrad Johannes Falke].
Explore the source record for details and available documents.
Anesthesiology↗
Biomedical subjects
R Rossaint
Publications and source records attributed to R Rossaint.
[Inhaled nitric oxide for the treatment of ARDS].
Acute respiratory distress syndrome (ARDS) is characterized by perfusion in favor of non-ventilated areas of the lungs as the main cause of intrapulmonary right-to-left shunt and hypoxemia. Therapeutic interventions to selectively influence pulmonary perfusion in ARDS became possible with the introduction of inhaled nitric oxide (iNO), which provided a way not only to reduce pulmonary hypertension, but also to acutely improve ventilation-perfusion mismatch, and thus to treat severe hypoxemia. Clinical studies in ARDS demonstrated that the combination of iNO with other interventions, such as positive end-expiratory pressure (PEEP) and prone positioning, yielded beneficial and additive effects on arterial oxygenation. Although randomized controlled trials of this concept have up to now failed to show an improved outcome, iNO is a valuable option for the treatment of severe refractory hypoxemia in ARDS patients.
Administration, Inhalation↗
[Neuromonitoring with S-100 protein in the intensive care unit].
During the last years biochemical neuromonitoring with various molecules such as S-100 protein has become popular. A huge number of investigations both experimental and clinical have been undertaken to determine diagnosis and prognosis of patients with acute neurologic diseases. This article gives a review on the current knowledge, indications and limitations on the use of S-100 protein with regard to most of the acute neurological diseases an intensivist is confronted with in everyday practice.
Brain Injuries↗
Factors independently associated with increased risk of pain development after ophthalmic surgery.
BACKGROUND AND OBJECTIVE: Little has been documented about the development of pain after ophthalmic surgery. This study was designed to assess the incidence and severity of postoperative pain following ophthalmic surgery, and to identify key factors independently associated with development of such pain. METHODS: In a prospective, observational cohort study, 500 patients undergoing elective ophthalmic surgery were examined by assessing numerical analogue scales and analgesic requirements. RESULTS: Depending on anatomical location of surgery, operations could be classified into creating 'more severe' or 'less severe pain'. Patients undergoing posterior segment, corneal and muscle surgery exhibited the highest numerical analogue scale scores (risk ratio 4.5, 95% CI 3.01-6.79, P < 0.0001). Anterior segment surgery, which per se did not create much pain, resulted in significantly more pain when performed under general anaesthesia compared to regional anaesthesia (risk ratio 6.52, 95% CI 2.33-18.2, P < 0.0001). No other factors independently associated with an increased risk of developing serious postoperative pain could be identified. CONCLUSIONS: Patients undergoing certain ophthalmic operations, especially if performed under general anaesthesia, are more likely to experience serious postoperative pain.
Adult↗
Xenon modulates neutrophil adhesion molecule expression in vitro.
BACKGROUND AND OBJECTIVE: Xenon reduces the infarct size after regional ischaemia in the rabbit heart in vivo, but the underlying mechanisms are unknown. Since adhesion molecules on neutrophils are closely involved in the pathophysiology of ischaemia/reperfusion injury and modulation of neutrophil function, we investigated the effect of xenon on neutrophil adhesion molecule expression in vitro. METHODS: Freshly isolated neutrophils were incubated with 30% or 60% xenon for 60 min. In unstimulated and after stimulation with either N-formyl-methionyl-leucyl-phenylalanine or phorbol-12-myristate-13-acetate neutrophil surface expression of PSGL-1, L-selectin, CD11a and CD11b were measured by flow cytometry. RESULTS: At both concentrations, xenon reduced the surface expression of PSGL-1 by 10% (P < 0.05), and of L-selectin by 15% (P < 0.05) in the 60% xenon group. Furthermore, N-formyl-methionyl-leucyl-phenylalanine activated neutrophils showed an increased removal of L-selectin from the neutrophil surface following incubation with xenon (30% compared to controls, P < 0.05). Neutrophil beta2-integrin expression was not altered by xenon. CONCLUSIONS: Xenon increases the removal of the selectins PSGL-1 and L-selectin from the neutrophil surface in vitro. Since both selectins are involved in the initial contact between neutrophils and endothelial cells, xenon may affect neutrophil adhesion to endothelium during ischaemia/reperfusion injury. However, because the beta2-integrin expression was unaffected by xenon, further investigations are required to clarify whether xenon may modulate neutrophil transmigration through endothelial cells in vivo.
Anesthetics, Inhalation↗
[Propofol-LCT versus propofol-MCT/LCT with or without lidocaine - a comparison on pain on injection].
OBJECTIVE: A disadvantage of Propofol (commercial preparation containing long-chain triglycerides; Propofol-LCT) is pain on injection, which is reported by 54 - 100 % of the patients. Many different approaches have been used in an attempt to decrease the pain on injection of propofol. The currently most efficacious treatment is lidocaine given intravenously with a tourniquet prior to Propofol injection. In previous studies, larger concentrations of free propofol in the aqueous phase of an emulsion were associated with more pain on injection. A new formulation of propofol (a mixture of long-chain and medium-chain triglycerides in the carrier emulsion; Propofol-MCT/LCT) reduces the incidence of pain on bolus injection. This study was designed to investigate, whether the use of Propofol-MCT/LCT alleviates pain on injection to a similar degree as pretreatment with lidocaine. METHODS: Eighty patients (ASA I - III) were randomly assigned to four groups according to a double-blinded protocol, to receive either lidocaine 2 % or normal saline given iv. with a 60 seconds tourniquet time before the injection of Propofol-LCT or Propofol-MCT/LCT. (group 1: 2 ml NaCl 0,9 %, Propofol-LCT; group 2: 2 ml NaCl 0,9 %, Propofol-MCT/LCT; group 3: 2 ml lidocaine 2 %, Propofol-LCT; group 4: 2 ml lidocaine 2 %, Propofol-MCT/LCT). Assessment of pain on injection was performed after 30 % of the induction dose was given. RESULTS: Pain on injection caused by Propofol-LCT with pre-treatment of lidocaine and Propofol-MCT/LCT alone is shown to be equivalent. Comparison of Propofol-MCT/LCT with pre-treatment of lidocaine and Propofol-LCT alone shows a statistical noticeable p-value of 0.035. Propofol-MCT/LCT with pre-treatment of lidocaine suggests a tendency of causing less pain compared to Propofol-MCT/LCT. Analysis of the postoperative questionnaire supplies no significant difference. CONCLUSION: The results suggest that pain on injection is reduced equivalent using either Propofol-MCT/LCT alone or Propofol-LCT with pre-treatment of lidocaine. Pre-treatment with lidocaine before Propofol-MCT/LCT seems to have an additional effect.
Adult↗
[Pulmonary gas exchange: classical and modern findings].
The functional anatomy of the pulmonary gas exchanger enables an adequate oxygenation even in extreme situations, e. g. high altitude. An important mechanism is the distribution of ventilation and pulmonary perfusion. With induction of anaesthesia a relevant ventilation-perfusion mismatch results in oxygenation impairment, which can be prevented by specific anaesthetic techniques.
Anesthesia↗
[Heating capabilities of fluid warming systems during low infusion rates].
OBJECTIVE: The aim of the study was to compare the effects of different fluid warming systems on their heating capabilities during low infusion rates. METHODS: Heating capabilities of four different fluid warming systems and their capabilities to warm fluids with 20 +/- 0.5 degrees C above 32 degrees C were measured: 1) Hotline(R) Fluid Warmer, 2) Gymar, using three disposable tubing systems - "Pediatric", "Standard", and "High-Flow", 3) Astotherm, and 4) Astotherm plus 260. Low to moderate infusion rates (100, 300, 600, and 900 ml/h) were achieved using motor pumps. Infusate temperatures were measured at 17 degrees C and 20 degrees C room temperature at the distal end of the disposable tubing. Statistical analysis was performed using a computer based program (NCSS). Differences between the groups were analysed by the unpaired Wilcoxon Test. Significance was defined with a p < 0.05. RESULTS: During low to moderate infusion rates (100 - 900 ml/h), infusate temperatures of > 32 degrees C were attained only by the Hotline-device in a reliable manner independent of the applied room temperature. The devices Astotherm plus 260 und Astotherm attained these temperatures during infusion rates of 300 ml/h and 600 ml/h respectively. Final temperatures of > 32 degrees C were maintained by Gymar during infusion rates of 600 ml/h, when the disposable tubing system "Pediatric" was used. Using the same device but different tubing systems, final temperatures of >32 degrees C were attained during 900 ml/h ("Standard") or failed ("High-Flow"). With all devices, increasing the room temperature by 3 degrees C was followed by higher infusate temperatures, which were more pronounced in those devices without disposable tubing warming (p < 0.01). CONCLUSION: In this laboratory investigation, Hotline performance was superior with respect to providing final temperatures > 32 degrees C during low to moderate infusion rates. Astotherm Plus 260 seems to be an alternative cost effective device in case of infusion rates of more than 300 ml/h.
Body Temperature↗
Effects of volatile anesthetics on cardiac ion channels.
The focus of the present review is on how interference with various ion channels in the heart may be the molecular basis for cardiac side-effects of gaseous anesthetics. Electrophysiological studies in isolated animal and human cardiomyocytes have identified the L-type Ca(2+) channel as a prominent target of anesthetics. Since this ion channel is of fundamental importance for the plateau phase of the cardiac action potential as well as for Ca(2+)-mediated electromechanical coupling, its inhibition may facilitate arrhythmias by shortening the refractory period and may decrease the contractile force. Effective inhibition of this ion channel has been shown for clinically used concentrations of halothane and, to a lesser extent, of isoflurane and sevoflurane, whereas xenon was without effect. Anesthetics furthermore inhibit several types of voltage-gated K(+) channels. Thereby, they may disturb the repolarization and bear a considerable risk for the induction of ventricular tachycardia in predisposed patients. In future, an advanced understanding of cardiac side-effects of anesthetics will derive from more detailed analyses of how and which channels are affected as well as from a better comprehension of how altered channel function influences heart function.
Anesthetics, Inhalation↗
The air elimination capabilities of pressure infusion devices and fluid-warmers.
Pressurised infusion devices may have only limited capability to detect and remove air during pressurised infusions. In order to assess pressure infusion systems with regard to their actual air elimination capabilities four disposable pressure infusion systems and fluid warmers were investigated: The Level 1 (L-1), Ranger (RA), Gymar (GY), and the Warmflo (WF). Different volumes of air were injected proximal to the heat exchanger and the remaining amount of air that was delivered at the end of the tubing was measured during pressurised infusions. Elimination of the injected air (100-200 ml) was superior by the RA system when compared to L-1 (p < 0.01). The GY and WF systems failed to eliminate the injected air. In conclusion, air elimination was best performed by the RA system. In terms of the risk of air embolism during pressurised infusions, improvements in air elimination of the investigated devices are still necessary.
Air↗
Influence of differences in body weight and volume management on experimental results in porcine models.
BACKGROUND: In contrast to humans, young pigs naturally have a low COPpl (12-16 mmHg versus 22-26 mmHg in young humans). Thus, behavior occurring when volume management is performed similar to human medicine might be different. Potentially underestimated intra- to extravascular fluid and solute shifts could influence time course of variables investigated. That is why we studied whether differences in the basic protocol for infusion therapy and different levels of COP according to age or body weight, respectively - impair reproducibility and reliability of experimental results. METHODS: Group A [n=6, lower body weight (LBW < 22 kg)] was treated with unrestricted infusion rates (UIR) adjusted to maintain a constant blood pressure; group B [n=6, higher body weight (HBW > 28 kg)] was treated with a restricted continuous infusion rate for fluid balance (RIR); group C (n=6) combined HBW and UIR protocol. Blood pressure, plasma solutes, diuresis, and peritoneal fluid were analysed. Statistical analysis was performed using Kruskal-Wallis test and Wilcoxon test. RESULTS: UIR-treated pigs with LBW (group A) developed ascites and demonstrated time dependent decreases of plasma solute concentrations whereas in pigs of group C mainly diuresis was increased and subcutaneous edema occurred. None of the protocols enabled constant blood pressure. DISCUSSION: In young pigs (LBW), an adaptive volume substitution using crystalloids to standardize blood pressure may induce fluid extravasation; in turn data may not show statistical significance, stable hemodynamics may not be achieved and changes in plasma solute concentrations may lead to false interpretations. RIR-strategy provided reproducible, plausible results and thus should be recommended in combination with pigs >29 kg BW for the use of porcine models.
Acute Kidney Injury↗
Modulating the pulmonary circulation: an update.
Pulmonary hypertension is a common finding in pulmonary circulatory disorders of different origin. Chronic pulmonary hypertension may develop due to either cardiopulmonary or systemic diseases whereas acute and acute-on-chronic pulmonary hypertension often occur in the course of cardiothoracic surgery. Right heart failure is the major risk particularly in the course of acute pulmonary hypertension. Thus, besides basic treatment of the underlying disease the use of vasodilators is a valuable therapeutic option to decrease right ventricular afterload, but intravenous vasodilators may provoke systemic arterial hypotension and impair gas exchange due to vasodilation of pulmonary shunt areas. Therefore, inhaled vasodilators such as nitric oxide and prostacyclin have been suggested for the treatment of pulmonary hypertension especially when concomitant hypoxemia is present due to a ventilation-perfusion mismatch. However, randomised controlled trials performed to evaluate long-term effects revealed different results: thus, in chronic pulmonary hypertension inhaled vasodilators improved outcome whereas the results for the treatment of the acute respiratory distress syndrome revealed beneficial effects only when used as a rescue and/or bridging therapy in severe hypoxemia. In cardiothoracic surgery, inhaled vasodilators have been shown to improve pulmonary circulation when severe pulmonary hypertension is present. Although effective in experimental studies no clear recommendation can be made in view to the use of other vasodilators such as phosphodiesterase inhibitors or endothelin antagonists. Likewise, the combination of different vasodilators merit further investigations to prove efficacy in randomised controlled trials.
Humans↗
Xenon, a modern anaesthesia gas.
Xenon is an interesting anesthetic as it appears to lack negative inotropicy and vasodilatation, giving great advantages to both patients with limited cardiovascular reserve or those who require hemodynamic stability. It has low toxicity and is not teratogenic. Xenon gives rapid induction and recovery, due to its low blood/gas partition coefficient (0.15), and has a MAC of 63%. Several vitro studies showed that Xenon may protect neural cells against ischaemic injury. Its low blood solubility can take to diffusion hypoxia if Xenon is not substituted by 100% oxygen at the end of anesthesia. It has been shown that, compared to other anesthetic regimens, Xenon anesthesia produces the highest regional blood flow in the brain, liver, kidney and intestine. In conclusion, the most important positive effects of Xenon are cardiovascular stability, cerebral protection and favourable pharmacokinetics. Negative points are high cost and the limited number of ventilators supplying Xenon.
Anesthetics, Inhalation↗
Anesthetic considerations in patients with chronic pulmonary diseases.
AIM: Increasing age and co-morbidities of patients admitted for surgery impose new challenges on the anesthesiologist. METHODS: Review of current literature regarding the perioperative management of patients with chronic pulmonary disease. RESULTS: If patients are treated adequately, surgery can be safely performed under regional and general anaesthesia. Major risk factors include type of surgery, type and duration of anesthesia, general health status and smoking history, but not certain lung function parameters. Regional anesthesia remains the first choice for intra- and postoperative care, and if general anesthesia is necessary, early extubation should be achieved. Non-invasive ventilation could be a possible alternative in weaning failure. CONCLUSION: Assessing the functional status of patients admitted to surgery remains a difficult task, and in patients identified at risk by clinical examination additional spirometry and blood gases may be helpful. If there are signs of respiratory failure, the anaesthetist should monitor the patient closely and invasively, yet there is no reason to deny any patient a substantially beneficial operation.
Anesthesia↗
[Evidence-based medicine of the acute respiratory distress syndrome].
Different therapeutic approaches have recently been developed for treatment of acute respiratory distress syndrome (ARDS) with the aim of improving the outcome. The clinical significance and success of these therapies is variable with respect to evidence based medicine. Lung protective ventilation is accepted as a proven therapy and the use of positive end-expiratory pressure as well as spontaneous breathing during controlled ventilation are common therapies. High frequency ventilation, partial liquid ventilation and pulmonary surfactant application are still in the experimental stage. The prone position is recommended for severe cases of ARDS and the application of inhaled nitric oxide and of extracorporeal membrane oxygenation is established in specialized centers for patients with imminent hypoxia. But for the routine use of these three therapies a clear improvement in outcome could not demonstrated. Recommended drug therapy is limited to the administration of stress doses of corticosteroids and a special anti-inflammatory enteral diet.
Evidence-Based Medicine↗
[Hyperpyrexia and rhabdomyolysis after ecstasy (MDMA) intoxication].
Abuse of 3,4-methylenedioxymethamphetamine (MDMA,Ecstasy) is still growing over the last years and reports of severe or even fatal complications, such as arrhythmias, hyperpyrexia, rhabdomyolysis, disseminated intravascular coagulopathy (DIC), acute renal or liver failure or brain oedema are also increasing. We report the case of a 21-year-old male who took a suicidal overdose of MDMA and subsequently developed severe hyperpyrexia (>43 degrees C/109.4 degrees F), rhabdomyolysis with an initial myoglobin level of 88,000 microg/l, disseminated intravascular coagulation (DIC) and beginning renal and liver failure. Infusing dantrolene 140 mg (2.5 mg/kg body weight) i.v. and using supportive cooling was effective in treating hyperpyrexia. To support renal function and diuresis we increased the intravenous fluid supply up to 5 l per day which led to a raised elimination of myoglobin, urea nitrogen and creatinine within 1 week. Hemodialysis was not necessary. DIC was treated according to laboratory parameters by supply of antithrombin (AT) III, fresh frozen plasma, prothrombin complex concentrates (PPSB) and continuous aprotinin 100,000 IE/h.
Acute Kidney Injury↗
Breathing pattern and workload during automatic tube compensation, pressure support and T-piece trials in weaning patients.
BACKGROUND AND OBJECTIVE: Automatic tube compensation has been designed as a new ventilatory mode to compensate for the non-linear resistance of the endotracheal tube. The study investigated the effects of automatic tube compensation compared with breathing through a T-piece or pressure support during a trial of spontaneous breathing used for weaning patients from mechanical ventilation of the lungs. METHODS: Twelve patients were studied who were ready for weaning after prolonged mechanical ventilation (10.2 +/- 8.4 days) due to acute respiratory failure. Patients with chronic obstructive pulmonary disease were excluded. Thirty minutes of automatic tube compensation were compared with 30 min periods of 7 cmH2O pressure support and T-piece breathing. Breathing patterns and workload indices were measured at the end of each study period. RESULTS: During T-piece breathing, the peak inspiratory flow rate (0.65 +/- 0.20 L s(-1)) and minute ventilation (8.9 +/- 2.7L min(-1)) were lower than during either pressure support (peak inspiratory flow rate 0.81 +/- 0.25 L s(-1) minute ventilation 10.2 +/- 2.3 L min(-1), respectively) or automatic tube compensation (peak inspiratory flow rate 0.75 +/- 0.26L s(-1); minute ventilation 10.8 +/- 2.7 L min(-1)). The pressure-time product as well as patients' work of breathing were comparable during automatic tube compensation (pressure-time product 214.5 +/- 104.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)) and T-piece breathing (pressure-time product 208.3 +/- 121.6 cmH2O s(-1) min(-1), patient work of breathing 1.1 +/- 0.4 J L(-1)), whereas pressure support resulted in a significant decrease in workload indices (pressure-time product 121.2 +/- 64.1 cmH2O s(-1) min(-1), patient work of breathing 0.7 +/- 0.4 J L(-1)). CONCLUSIONS: In weaning from mechanical lung ventilation, patients' work of breathing during spontaneous breathing trials is clearly reduced by the application of pressure support 7 cmH2O, whereas the workload during automatic tube compensation corresponded closely to the values during trials of breathing through a T-piece.
Adult↗
Effect of isoflurane on monocyte adhesion molecule expression in human whole blood.
BACKGROUND: Recruitment of monocytes to inflamed tissue is a crucial step in the acute inflammatory reaction. Adherence of monocytes to endothelial cells followed by transmigration depends on monocyte surface adhesion molecules, inflammatory cytokines and chemoattractant chemokines. In the present study, we determined the effect of isoflurane on monocyte adhesion receptor expression in vitro. METHODS: Citrated whole blood was incubated for 60 min with either 0.5 or 1 MAC isoflurane. In unstimulated blood samples and after stimulation with N-formyl-methionyl-leucyl-phenylalanine (FMLP) monocyte cell-surface expression of the selectins PSGL-1 and L-selectin, and the beta2-integrins CD11a and CD11b were evaluated by flow cytometry. RESULTS: Isoflurane reduced significantly the expression of PSGL-1 on unstimulated monocytes, whereas the remaining selectins and beta2-integrins were not affected. At both concentrations, the FMLP-induced removal of PSGL-1 from the monocyte surface was increased. Furthermore, at 1 MAC isoflurane the FMLP-induced increase in CD11a expression was significantly inhibited. The surface expression of L-selectin and CD11b was not affected following exposure to isoflurane. CONCLUSION: Isoflurane increases the removal of the selectin PSGL-1 from the monocyte surface. Since PSGL-1 is important during the initial step of monocyte adhesion to endothelial P-selectin, the decrease in monocyte surface PSGL-1 may have profound effects on monocyte-endothelial interactions. Furthermore, the effects of isoflurane on monocyte adhesion molecule expression are different from those reported for neutrophils.
Anesthetics, Inhalation↗