Serendipitous thrombolysis of a thrombosed arteriovenous graft during cardiopulmonary resuscitation and treatment of suspected pulmonary embolism.

Acute pulmonary embolism and cardiac arrest are rare complications of graft declotting interventions. This case report describes a successful serendipitous thrombolysis of a thrombosed arteriovenous graft during cardiopulmonary resuscitation and treatment of suspected pulmonary embolism in a 72-year-old male patient.

[Perioperative anxiety and fear of death]. / Perioperative Ängste und die Angst vor dem Tod.

An important field of anesthesiology but also of psychiatry and psychotherapy, is perioperative anxiety and especially the fear of death. In this review article the most important types of anxiety in the individual phases before, during and after surgery are presented and diagnostic aspects as well as risk factors are discussed. Benzodiazepines can classically be used therapeutically here, but in recent years the preoperative anxiety-reducing effects of e.g., supporting talks, acupuncture, aroma therapy, and relaxation methods have come more into focus, because benzodiazepines promote postoperative delirium, which significantly increases morbidity and mortality. Perioperative fear of death should, however, be given greater clinical and scientific attention in order not only to have a better understanding and preoperative care of patients, but also to reduce adverse consequences during surgery and afterwards.

[Speckle Tracking Echocardiography - a New Tool for the Intensive Care Unit?] / Speckle-Tracking-Echokardiografie ­ ein neues Tool für die Intensivstation?

The noninvasive evaluation of cardiac morphology and function by echocardiography is an essential part of modern intensive care therapy. However, this procedure can be challenging and beginners often lack the ability to objectively state the correct global and regional myocardial function. Recent developments allow a semi-automatic deformation (strain) analysis by a couple of more objective respective parametric techniques. Strain describes the change in length of a myocardial segment during the cardiac cycle. While this is primarily a regional analysis, an insight into the global left ventricular deformation is possible by averaging all relevant segments. Speckle tracking echocardiography (STE) is actually the only clinically relevant technique and is well scientifically and clinically approved. The advantages of STE are the angle-independency, the ease and fastness of its use, the availability at the bedside and low costs. Through proven good reproducibility it should be a good method for repeated analysis even by different echocardiographers. However, actually the greatest disadvantage is the variation of measures between different vendors of ultrasound machines and software-packages. At the moment, a task force of leading echocardiography experts and industry personal is working on a solution. Normal values have been published for healthy collectives and STE has been in use in the majority of cardiac diseases. Besides from a few research studies, the usage in critically ill patients actually is still limited.

Minimal-flow ECCO2R in patients needing CRRT does not facilitate lung-protective ventilation.

Extracorporeal CO2 removal (ECCO2R) is intended to facilitate lung protective ventilation in patients with hypercarbia. The combination of continuous renal replacement therapy (CRRT) and minimal-flow ECCO2R offers a promising concept for patients in need of both. We hypothecated that this system is able to remove enough CO2 to facilitate lung protective ventilation in mechanically ventilated patients. In 11 ventilated patients with acute renal failure who received either pre- or postdilution CRRT, minimal-flow ECCO2R was added to the circuit. During 6 h of combined therapy, CO2 removal and its effect on facilitation of lung-protective mechanical ventilation were assessed. Ventilatory settings were kept in assisted or pressure-controlled mode allowing spontaneous breathing. With minimal-flow ECCO2R significant decreases in minute ventilation, tidal volume and paCO2 were found after one and three but not after 6 h of therapy. Nevertheless, no significant reduction in applied force was found at any time during combined therapy. CO2 removal was 20.73 ml CO2/min and comparable between pre- and postdilution CRRT. Minimal-flow ECCO2R in combination with CRRT is sufficient to reduce surrogates for lung-protective mechanical ventilation but was not sufficient to significantly reduce force applied to the lung. Causative might be the absolute amount of CO2 removal of only about 10% of resting CO2 production in an adult as we found. The benefit of applying minimal flow ECCO2R in an uncontrolled setting of mechanical ventilation might be limited.

Interhospital transport of ARDS patients on extracorporeal membrane oxygenation.

Veno-venous extracorporeal membrane oxygenation (ECMO) can be a lifesaving therapy for patients with severe acute respiratory distress syndrome (ARDS). ECMO is a technically complex and challenging procedure and should therefore only be performed in specialized centers. Transporting ARDS patients to ECMO centers for treatment can be dangerous because of the risk of hypoxemia during transport. This raises the question if ECMO should not be already initiated in the transferring hospital before transport. Over a 5-year period, we studied ARDS patients who had been transported to our department by our mobile ECMO team for further treatment after ECMO had already been initiated at the referring hospital. Data for analysis were obtained from our patient data management system (PDMS), the referral documents, and from the referring hospitals. Seventy-five patients meeting the selection criteria were studied. All had been successfully cannulated in the transferring hospitals. They were transported to our ECMO center by helicopter (n = 34) or mobile intensive care units (n = 41). No patient died during transport. Forty four of the patients were transported at night. Twenty-six patients (35%) died in our intensive care unit due to a therapy refractory course, comorbidities or limitation of therapy. Patients on ECMO therapy can be safely transferred to a specialist center. Setting up ECMO in an unfamiliar location and the subsequent patient transport can be very challenging and should only be performed by a highly trained, experienced team.

High-frequency oscillatory ventilation guided by transpulmonary pressure in acute respiratory syndrome: an experimental study in pigs.

BACKGROUND: Recent clinical studies have not shown an overall benefit of high-frequency oscillatory ventilation (HFOV), possibly due to injurious or non-individualized HFOV settings. We compared conventional HFOV (HFOVcon) settings with HFOV settings based on mean transpulmonary pressures (PLmean) in an animal model of experimental acute respiratory distress syndrome (ARDS). METHODS: ARDS was induced in eight pigs by intrabronchial installation of hydrochloric acid (0.1 N, pH 1.1; 2.5 ml/kg body weight). The animals were initially ventilated in volume-controlled mode with low tidal volumes (6 ml kg- 1) at three positive end-expiratory pressure (PEEP) levels (5, 10, 20 cmH2O) followed by HFOVcon and then HFOV PLmean each at PEEP 10 and 20. The continuous distending pressure (CDP) during HFOVcon was set at mean airway pressure plus 5 cmH2O. For HFOV PLmean it was set at mean PL plus 5 cmH2O. Baseline measurements were obtained before and after induction of ARDS under volume controlled ventilation with PEEP 5. The same measurements and computer tomography of the thorax were then performed under all ventilatory regimens at PEEP 10 and 20. RESULTS: Cardiac output, stroke volume, mean arterial pressure and intrathoracic blood volume index were significantly higher during HFOV PLmean than during HFOVcon at PEEP 20. Lung density, total lung volume, and normally and poorly aerated lung areas were significantly greater during HFOVcon, while there was less over-aerated lung tissue in HFOV PLmean. The groups did not differ in oxygenation or extravascular lung water index. CONCLUSION: HFOV PLmean is associated with less hemodynamic compromise and less pulmonary overdistension than HFOVcon. Despite the increase in non-ventilated lung areas, oxygenation improved with both regimens. An individualized approach with HFOV settings based on transpulmonary pressure could be a useful ventilatory strategy in patients with ARDS. Providing alveolar stabilization with HFOV while avoiding harmful distending pressures and pulmonary overdistension might be a key in the context of ventilator-induced lung injury.

A comparison between the GlideScope® classic and GlideScope® direct video laryngoscopes and direct laryngoscopy for nasotracheal intubation.

DESIGN: Prospective, randomized, clinical trial. SETTING: University hospital operation room. PATIENTS: 104 patients scheduled for elective dental or maxillofacial surgery were randomized to two groups: GlideScope® classic (GSc) and GlideScope® direct (GSd). INTERVENTIONS: We compared the video laryngoscopes GSc and GSd with each other and with direct laryngoscopy (DL) for nasotracheal intubation with regard to visualization of the glottis, intubation success rate, and required time for and ease of intubation. The aim of the study was to determine whether the use of the video monitor alone reduced the difficulty of nasotracheal intubation, and also to investigate whether the GSc, with its blade designed for difficult airways, had an additional advantage over the video-assisted Macintosh blade (GSd). In both groups the investigators first performed laryngoscopy using the GSd blade, first with the monitor concealed and then with it visible. In the GSd group the tube was then inserted into the trachea with the video monitor screen visible. In the GSc group, the GSd blade was exchanged for the GSc blade, which was then used when inserting the tube with the screen visible. RESULTS: The success rates and the times required for the video-assisted nasotracheal intubation did not differ significantly between the groups. A better view was obtained more often in the GSc group. In both groups there was a significant difference between direct laryngoscopy and the video-assisted intubation technique. Overall, using the video monitor improved the C-L scores by one grade in 52% and by two grades in 11% of the patients. CONCLUSIONS: Video laryngoscopes increase the ease of nasotracheal intubation. The GSc blade might provide a better view of the laryngeal structures in case of a difficult airway than the GSd blade. Video laryngoscopy per se gives a better view of the glottis than direct laryngoscopy.

Effects of acute intracranial hypertension on extracerebral organs: a randomized experimental study in pigs.

BACKGROUND: The study was conducted to determine the effects of isolated acute intracranial hypertension (AICH) on extracerebral organs. DESIGN: A total of 14 mechanically ventilated pigs were randomized to two groups of seven each: (1) control and (2) AICH. METHODS: AICH was induced by inflating an intracranial balloon catheter. The inflation volume was adjusted to keep intracranial pressure between 30 and 40 cm H2O. Hemodynamics, gas-exchange, and global oxygen delivery parameters were observed over a 4-hour period. At the end of the 4-hour period, tissue samples of heart, lungs, liver, and kidneys were collected and histologically graded for inflammation, edema, and cell damage (necrosis) using semiquantitative scores. RESULTS: Animals with AICH had increased heart rate and cardiac output, and higher scores for inflammation, edema, and necrosis in heart, lung, kidney, and liver tissues (all p < 0.05). Peripheral and mixed-venous oxygen saturations were unaffected. CONCLUSIONS: Isolated AICH induces injury to multiple extracerebral organs, even in the absence of hypoperfusion or hypoxemia.

Effects of pulmonary acid aspiration on the lungs and extra-pulmonary organs: a randomized study in pigs.

INTRODUCTION: There is mounting evidence that injury to one organ causes indirect damage to other organ systems with increased morbidity and mortality. The aim of this study was to determine the effects of acid aspiration pneumonitis (AAP) on extrapulmonary organs and to test the hypothesis that these could be due to circulatory depression or hypoxemia. METHODS: Mechanically ventilated anesthetized pigs were randomized to receive intrabronchial instillation of hydrochloric acid (n = 7) or no treatment (n = 7). Hydrochloric acid (0.1 N, pH 1.1, 2.5 ml/kg BW) was instilled into the lungs during the inspiratory phase of ventilation. Hemodynamics, respiratory function and computer tomography (CT) scans of lung and brain were followed over a four-hour period. Tissue samples of lung, heart, liver, kidney and hippocampus were collected at the end of the experiment. RESULTS: Acid instillation caused pulmonary edema, measured as increased extravascular lung water index (ELWI), impaired gas exchange and increased mean pulmonary artery pressure. Gas exchange tended to improve during the course of the study, despite increasing ELWI. In AAP animals compared to controls we found: a) cardiac leukocyte infiltration and necrosis in the conduction system and myocardium; b) lymphocyte infiltration in the liver, spreading from the periportal zone with prominent areas of necrosis; c) renal inflammation with lymphocyte infiltration, edema and necrosis in the proximal and distal tubules; and d) a tendency towards more severe hippocampal damage (P > 0.05). CONCLUSIONS: Acid aspiration pneumonitis induces extrapulmonary organ injury. Circulatory depression and hypoxemia are unlikely causative factors. ELWI is a sensitive bedside parameter of early lung damage.

Accuracy of prehospital diagnoses by emergency physicians: comparison with discharge diagnosis.

OBJECTIVE: A correct prehospital diagnosis of emergency patients is crucial as it determines initial treatment, admitting specialty, and subsequent treatment. We evaluated the diagnostic accuracy of emergency physicians. METHODS: All patients seen by six emergency physicians staffing the local emergency ambulance and rescue helicopter services during an 8-month period were studied. The ambulance and helicopter physicians had 3 and 4 years, respectively, training in anesthesia and intensive care medicine. The admission diagnoses were compared with the discharge diagnoses for agreement. Time of day of the emergency call, patients' age, and sex, living conditions, and presenting symptoms were evaluated as contributing factors. RESULTS: Three hundred and fifty-five ambulance and 241 helicopter deployment protocols were analyzed. The overall degree of agreement between initial and discharge diagnoses was 90.1% with no difference attributable to years of experience. The lowest agreement rate was seen in neurological disorders (81.5%), with a postictal state after an unobserved seizure often being diagnosed as a cerebrovascular accident. Inability to obtain a complete medical history (e.g. elderly patients, patients in nursing homes, neurological impairment) was associated with a lower agreement rate between initial and discharge diagnoses (P<0.05). CONCLUSION: Medical history, physical examination, ECG, and blood glucose enabled a correct diagnosis in most cases, but some were impossible to resolve without further technical and laboratory investigations. Only a few were definitively incorrect. A detailed medical history is essential. Neurological disorders can present with misleading symptoms and when the diagnosis is not clear it is better to assume the worst case.

Effects of high-frequency oscillatory ventilation on systemic and cerebral hemodynamics and tissue oxygenation: an experimental study in pigs.

BACKGROUND: In this study, we compare the effects of high frequency oscillatory ventilation (HFOV) with those of lung-protective volume-controlled ventilation (VCV) on cerebral perfusion, tissue oxygenation, and cardiac function with and without acute intracranial hypertension (AICH). METHODS: Eight pigs with healthy lungs were studied during VCV with low tidal volume (V(T): 6 ml kg(-1)) at four PEEP levels (5, 10, 15, 20 cm H(2)O) followed by HFOV at corresponding transpulmonary pressures, first with normal ICP and then with AICH. Systemic and pulmonary hemodynamics, cardiac function, cerebral perfusion pressure (CPP), cerebral blood flow (CBF), cerebral tissue oxygenation, and blood gases were measured after 10 min at each level. Transpulmonary pressures (TPP) were calculated at each PEEP level. The measurements were repeated with HFOV using continuous distending pressures (CDP) set at TPP plus 5 cm H(2)O for the corresponding PEEP level. Both measurement series were repeated after intracranial pressure (ICP) had been raised to 30-40 cm H(2)O with an intracranial balloon catheter. RESULTS: Cardiac output, stroke volume, MAP, CPP, and CBF were significantly higher during HFOV at normal ICP. Systemic and cerebral hemodynamics was significantly altered by AICH, but there were no differences attributable to the ventilatory mode. CONCLUSION: HFOV is associated with less hemodynamic compromise than VCV, even when using small tidal volumes and low mean airway pressures. It does not impair cerebral perfusion or tissue oxygenation in animals with AICH, and could, therefore, be a useful ventilatory strategy to prevent lung failure in patients with traumatic brain injury.

Acute effects of intracranial hypertension and ARDS on pulmonary and neuronal damage: a randomized experimental study in pigs.

PURPOSE: To determine reciprocal and synergistic effects of acute intracranial hypertension and ARDS on neuronal and pulmonary damage and to define possible mechanisms. METHODS: Twenty-eight mechanically ventilated pigs were randomized to four groups of seven each: control; acute intracranial hypertension (AICH); acute respiratory distress syndrome (ARDS); acute respiratory distress syndrome in combination with acute intracranial hypertension (ARDS + AICH). AICH was induced with an intracranial balloon catheter and the inflation volume was adjusted to keep intracranial pressure (ICP) at 30-40 cmH2O. ARDS was induced by oleic acid infusion. Respiratory function, hemodynamics, extravascular lung water index (ELWI), lung and brain computed tomography (CT) scans, as well as inflammatory mediators, S100B, and neuronal serum enolase (NSE) were measured over a 4-h period. Lung and brain tissue were collected and examined at the end of the experiment. RESULTS: In both healthy and injured lungs, AICH caused increases in NSE and TNF-alpha plasma concentrations, extravascular lung water, and lung density in CT, the extent of poorly aerated (dystelectatic) and atelectatic lung regions, and an increase in the brain tissue water content. ARDS and AICH in combination induced damage in the hippocampus and decreased density in brain CT. CONCLUSIONS: AICH induces lung injury and also exacerbates pre-existing damage. Increased extravascular lung water is an early marker. ARDS has a detrimental effect on the brain and acts synergistically with intracranial hypertension to cause histological hippocampal damage.

Initial ventilation through laryngeal tube instead of face mask in out-of-hospital cardiopulmonary arrest is effective and safe.

INTRODUCTION: Bag-valve-mask ventilation is recommended as the initial airway management option for paramedics during cardiopulmonary resuscitation, although this technique requires considerable skill and is associated with the risk of stomach insufflation, regurgitation, and aspiration. The present two-phase study investigated the efficacy and safety of the laryngeal tube (LT-D) used by paramedics as the sole technique for ventilation in out-of-hospital cardiac arrest. METHODS: Paramedics staffing the emergency services' ambulances were selected for the study and trained in the use of the LT-D (phase I). They were then requested to use the device in patients requiring out-of-hospital cardiopulmonary resuscitation without prior bag-valve-mask ventilation. Patients were evaluated with regard to successful placement and effective ventilation using the airway. On arrival at the scene, the emergency physician replaced the LT-D with an endotracheal tube and assessed the incidence of regurgitation and injuries to the airways (phase II). RESULTS: Forty patients were enrolled into this study. One was excluded from analysis because of protocol violation. Insertion of the LT-D was successful and ventilation was effective in 33 patients (85%). Ventilation was not possible in six patients (15%) because of cuff rupture (n = 3) or massive regurgitation and aspiration before LT-D insertion (n = 3). No patient regurgitated after tube placement. No airway injuries were observed. The participants rated ventilation using the LT-D as effective. CONCLUSION: The LT-D is feasible and effective for airway management and ventilation when used by paramedics in out-of-hospital cardiopulmonary resuscitation and can be recommended as the sole technique in such situations.