Coexistence of antithrombin deficiency and suspected inferior vena cava atresia in an adolescent and his mother - case report and clinical implications.

BACKGROUND: Antithrombin deficiency (ATD) is an autosomal dominant thrombophilia presenting with varying phenotypes. In pediatric patients with ATD, thrombosis typically develops during the neonatal period or adolescence. However, to date there are no consistent recommendations on the therapeutic management of children with ATD. Inferior vena cava atresia (IVCA) belongs to a range of congenital or acquired vena cava malformations and is described as an independent risk factor for thrombosis. The present case report explores two cases of combined ATD and IVCA in an adolescent and his mother. CASE PRESENTATION: A 14-year-old male presented with extensive deep venous thromboses (DVTs) of both lower extremities as well as an IVCA. The patient had previously been diagnosed with an asymptomatic ATD without therapeutic consequences at that time. His mother was suffering from an ATD and had herself just been diagnosed with IVCA, too. The DVTs in the adolescent were treated by systemic anticoagulation and catheter-directed local thrombolysis causing favourable results. Yet, despite adequate oral anticoagulation the DVTs in both lower extremities reoccurred within 1 week after the patient was discharged from hospital. This time, thrombolysis could not be fully achieved. Surprisingly, probing and stenting of the IVCA was achieved, indicating an acquired IVCA which could have occurred after undetected thrombosis in early childhood. Genetic analyses showed the same mutation causing ATD in both son and mother: heterozygote missense mutation c.248 T > C, p.(Leu83Pro), within the heparin binding domain of antithrombin. This mutation was never reported in mutation databases before. CONCLUSIONS: To our knowledge this is the first case report discussing combined ATD and IVCA in two family members. Since ATDs present with clinical heterogeneity, taking a thorough family history is crucial for the anticipation of possible complications in affected children and decisions on targeted diagnostics and therapeutic interventions. Affected families must be educated on risk factors and clinical signs of thrombosis and need an immediate diagnostic workup in case of clinical symptoms. IVCA in patients with ATD could occur due to thrombotic occlusion at a very early age. Therefore, in case of family members with IVCA and ATD ultrasound screening in newborns should be considered.

[New aspects of rapid sequence induction including treatment of pulmonary aspiration]. / Neue Aspekte der "rapid sequence induction" einschließlich Behandlung der pulmonalen Aspiration.

Pulmonary aspiration of solid components leads to displacement of the tracheobronchial tree, the aspiration of acidic gastric juices to chemical pneumonitis (Mendelson's syndrome) and the aspiration of oropharyngeal secretions or gastrointestinal pathogens to aspiration pneumonia. Principally, pulmonary aspiration can occur at any stage of anesthesia. In the clinical routine the aim must therefore be to identify those patients who have an increased risk of aspiration. When this is successful, measures can be taken to reduce the risk; these can be regional anaesthesia or the performance of general anaesthesia as rapid sequence induction (RSI). If severe pulmonary aspiration occurs despite all preventive measures, mostly during induction of anaesthesia, extensive experience and rapid action are necessary. This can only be achieved if the induction to RSI is performed by three persons with supervision of the trainee anaesthetist by a consultant anaesthetist.

[Implementation of emergency classifications-Where do we stand? : Results of a nationwide survey]. / Der Umgang mit Notfallklassifikationen ­ Wo stehen wir? : Ergebnisse einer deutschlandweiten Umfrage.

BACKGROUND: This study aimed to determine the current state of implementation of the recommendations for the classification of emergency surgery published in 2016 by the German societies of anesthesiology (BDA/DGAI), surgery (BDC/DGCH) and operating room management (VOPM). METHODS: Based on these societies' recommendations, various organizational issues were explored using an online questionnaire that was limited to German operating room (OR) managers and coordinators for hospitals that had surgical programs and at least 200 hospital beds. RESULTS: A total of 550 hospitals were contacted and 274 participated in the survey (49.8%). Of these 70.7% reported that they had implemented the recommendations, and 15.2% were aware of the recommendations but did not consistently apply them. Of the participating OR managers and coordinators that had either implemented or were aware of the recommendations, 78.2% agreed that the standardized definition of medical emergencies led to improvements in emergency treatment but 33.6% stated that the defined response intervals for emergency categories induced a certain degree of subjectivity in categorizing emergencies. Additional in-house guidelines specifically for the most frequent surgeries were or would be welcomed by 80.1% of the respondents and 39.1% of the surveyed hospitals had already implemented such guidelines. Of the OR managers and coordinators, 62.9% were informed about their emergency volumes and 47.3% stated that they regularly assessed them. There was no dedicated capacity for emergency care in 65.2% of hospitals. Of the respondents 3.9% stated that a separate emergency OR was reserved with a freely available team, which, during core operating hours, could be used for interdisciplinary emergency care and 26.2% of hospitals considered the capacity required for emergency procedures when planning the OR program or determining OR capacities. CONCLUSION: The recommendations for classifying emergency operations are an essential and generally accepted control mechanism in OR coordination. They simplify interdisciplinary coordination and communication when dynamically incorporating emergency procedures into an OR program. Most OR managers and coordinators view the recommendations as improving the speed of action in emergency care. To support the adoption of emergency classifications within an organization it may be advisable to incorporate them into the OR statutes and integrate them within the hospital information systems. The majority of participants supported additional specifications based on medical indicators for classifying the most frequent emergency operations. Being cognizant of key metrics concerning in-house emergency volume represents a crucial basis for interdisciplinary OR management and emergency care integration. Contrary to common perception, blocking fixed OR capacities remains the exception. When establishing a concept to provide emergency capacity, it is advisable to align developments with demand calculations based on in-house figures and to emphasize interdisciplinary participation and consensus.

[Sepsis-associated encephalopathy : A nationwide survey on diagnostic procedures and neuromonitoring in German intensive care units]. / Sepsis-assoziierte Enzephalopathie : Eine bundesweite Umfrage zu Verfahren der Diagnostik und des Neuromonitorings auf deutschen Intensivstationen.

BACKGROUND: Sepsis-associated encephalopathy (SAE) is one of the most frequent causes of neurocognitive impairment in intensive care patients. It is associated with increased hospital mortality and poor long-term neurocognitive outcome. To date there are no evidence-based recommendations for the diagnostics and neuromonitoring of SAE. OBJECTIVE: The aim of the study was to evaluate the current clinical practice of diagnostics and neuromonitoring of SAE on intensive care units (ICU) in Germany. MATERIAL AND METHODS: Based on available literature focusing on SAE, a questionnaire consisting of 26 items was designed and forwarded to 438 members of the Scientific Working Group for Intensive Care Medicine (WAKI) and the Scientific Working Group for Neuroanesthesia (WAKNA) as an online survey. RESULTS: The total participation rate in the survey was 12.6% (55/438). A standardized diagnostic procedure of SAE was reported by 21.8% (12/55) of the participants. The majority of participants preferred delirium screening tools (50/55; 90.9%) and the clinical examination (49/55; 89.1%) to detect SAE. Brain imaging (26/55; 47.3%), laboratory/biomarker determination (15/55; 27.3%), electrophysiological techniques (14/55; 25.5%) and cerebrospinal fluid examination (12/55; 21.8%) are less frequently performed. The follow-up examination of SAE is most frequently performed by a clinical examination (45/55; 81.8%). Neuromonitoring techniques, such as continuous electroencephalography (31/55; 56.4%), transcranial doppler sonography (31/55; 56.4%) and near-infrared spectroscopy (18/55, 32.7%) are not frequently used. We observed statistically significant differences between the theoretically attributed importance and clinical practice. The great majority of respondents (48/55; 87.3%) endorse the development of guidelines containing recommendations for diagnostics and neuromonitoring in SAE. DISCUSSION: This explorative survey demonstrated a great heterogeneity in diagnostics and neuromonitoring of SAE in German ICUs. Uniform concepts have not yet been established but are desired by the majority of study participants. Innovative biomarkers of neuroaxonal injury in blood and cerebrospinal fluid as well as electrophysiological and brain imaging techniques could provide valuable prognostic information on the neurocognitive outcome of patients and would thus be a useful addition to the clinical assessment of ICU patients with SAE.

[Perioperative optimization using hemodynamically focused echocardiography in high-risk patients-A practice guide]. / Perioperative Optimierung mittels auf die Hämodynamik fokussierter Echokardiographie bei Hochrisikopatienten ­ eine Praxisanleitung.

BACKGROUND: The number of high-risk patients undergoing surgery is steadily increasing. In order to maintain and, if necessary, optimize perioperative hemodynamics as well as the oxygen supply to the organs (DO2) in this patient population, a timely assessment of cardiac function and the underlying pathophysiological causes of hemodynamic instability is essential for the anesthesiologist. A variety of hemodynamic monitoring procedures are available for this purpose; however, due to method-immanent limitations they are often not able to directly identify the underlying cause of cardiovascular impairment. OBJECTIVE: To present a stepwise algorithm for a perioperative echocardiography-based hemodynamic optimization in noncardiac surgery high-risk patients. In this context, echocardiography on demand according to international guidelines can be performed under certain conditions (hemodynamic instability, nonresponse to hemodynamic treatment) as well as in the context of a planned intraoperative procedure, mostly as a transesophageal echocardiography. METHODS AND RESULTS: Hemodynamically focused echocardiography as a rapidly available bedside method, enables the timely diagnosis and assessment of cardiac filling obstructions, volume status and volume response, right and left heart function, and the function of the heart valves. CONCLUSION: Integrating all echocardiographic findings in a differentiated assessment of the patient's cardiovascular function enables a (patho)physiologically oriented and individualized hemodynamic treatment.

[Perioperative pharmacological circulatory support in daily clinical routine]. / Perioperative medikamentöse Kreislaufunterstützung in der täglichen Routine.

Perioperative phases of hypotension are associated with an increase in postoperative complications and organ damage. Whereas some years ago hemodynamic stabilization was primarily carried out by volume supplementation, in recent years the use and dosing of cardiovascular-active substances has significantly increased. But like intravascular volume therapy, also substances with a cardiovascular effect have therapeutic margins, and thus, potential side effects. This review article discusses indications for each cardiovascular-active agent, weighing up advantages and disadvantages. Special attention is paid to the question how to administrate them: central venous catheter vs. peripheral indwelling venous cannula. The authors come to the conclusion that it is not a question of whether it is principally allowed to apply cardiovascular-active drugs via peripheral veins but more importantly, what should be taken into consideration if a peripheral venous access is used. This article provides concise recommendations.

[Perioperative blood pressure management : What is the optimal pressure?] / Perioperatives Blutdruckmanagement : Was ist der optimale Druck?

BACKGROUND: Measurement of blood pressure is part of standard monitoring procedures in anesthesia, in addition to the other vital parameters of heart frequency and peripheral oxygen saturation. In recent years the relevance of the duration and extent of perioperative episodes of hypotension for the occurrence of postoperative complications or even increased mortality have become the focus of scientific investigations. OBJECTIVE: The aim of this review is to briefly recapitulate the physiological aspects of blood pressure and to describe the pathophysiology and risk factors of perioperative hypotension. It describes which potential organ damage can be caused by hypotension and discusses which perioperative blood pressure values are acceptable without harming the patient. METHODS: Review and analysis of the currently available literature. RESULTS: Perioperative hypotension is defined by either absolute systolic arterial pressure (SAP) or mean arterial pressure (MAP) thresholds and by relative blood pressure declines from an individual preoperative baseline value. For the definition of absolute and relative thresholds it needs to be considered that the ultimate target is an adequate perfusion pressure (and not the MAP) and that the preinduction blood pressure is a poor reflection of the patients' normal blood pressure profile. Risk factors for an intraoperative drop in blood pressure are advanced age, higher American Society of Anesthesiologists (ASA) status, low blood pressure prior to induction of anesthesia, the premedication, e.g. angiotensin-converting enzyme (ACE) inhibitors, the anesthesia technique (combination of general and epidural anesthesia) and emergency surgery. The lowest tolerable intraoperative blood pressure should be defined according to the individual patient's preoperative blood pressure and risk profile. Individual thresholds should be determined for the severity and duration of intraoperative hypotension. Empirically, MAP values <65 mm Hg and relative pressure declines of >20-30% are often recommended as thresholds. Below critical blood pressure values the risk of postoperative organ damage (myocardium, kidneys and central nervous system) and mortality increases with longer duration of hypotension. Older people and high-risk patients (e.g. patients in vascular surgery) have a poorer and shorter tolerance of low blood pressure. Postoperative organ complications can be minimized by maintenance of an adequate intraoperative blood pressure CONCLUSION: Anesthesiologists should avoid extensive and prolonged hypotension by timely interventions in order to improve the postoperative outcome of patients.

[Foundations of Volumetric capnography : Principles of monitoring of metabolism and hemodynamics]. / Grundlagen der Volumetrischen Kapnographie : Prinzipien der Überwachung von Stoffwechsel und Hämodynamik.

Capnography is the graphical representation of the carbon dioxide (CO2) concentration in expired air. Using this monitoring procedure, the kinetics of CO2 of mechanically ventilated patients can be assessed in a noninvasive way and in real time. This article highlights the importance, particularly of volumetric capnography (VCap), for clinical monitoring of mechanically ventilated patients. The procedure provides important information on the breathing, ventilation, metabolism and hemodynamics of patients.

[Volumetric capnography for analysis and optimization of ventilation and gas exchange]. / Volumetrische Kapnographie zur Analyse und Optimierung von Ventilation und Gasaustausch.

Capnography as the graphical representation of the expiratory carbon dioxide (CO2) concentration, is an essential component of monitoring of every ventilated patient, in addition to pulse oximetry. Capnography demonstrates the kinetics of CO2 in a noninvasive way and in real time. In the daily routine anesthesia, it mainly serves for identification of the correct intubation and adaptation of the respiratory minute volume to be applied; however, capnography can also provide much more far-reaching and clinically particularly valuable information, especially in the form of volumetric capnography (VCap) that is not yet so widely clinically available. These include monitoring and optimization of ventilation and assessment of gas exchange. This article presents parameters for making decisions at the bedside, which could previously only be obtained by extensive, more invasive, nonautomated procedures.

International survey of neurosurgical anesthesia (iSonata) : An international survey of current practices in neurosurgical anesthesia.

BACKGROUND: No standardized recommendations have been currently defined for anesthesia management of patients undergoing elective intracranial surgery. It can therefore be assumed that international clinical institutions have diverging approaches or standard operating procedures (SOP) which determine the type of general anesthesia, hemodynamic management, neuromuscular blockade, implementation of hypothermia and postoperative patient care. OBJECTIVE: This international survey aimed to assess perioperative patient management during elective intracranial procedures. This survey was performed from February to October 2018 and 311 neurosurgical, maximum care centers across 19 European countries were contacted. The aim was to evaluate the anesthesia management to provide relevant data of neuroanesthesia practices across European centers. The survey differentiated between vascular and non-vascular as well as supratentorial and infratentorial procedures. RESULTS: A total of 109 (35.0%) completed questionnaires from 15 European countries were analyzed. The results illustrated that total intravenous anesthesia was most commonly implemented during elective intracranial procedures (83.8%). All centers performed endotracheal intubation prior to major intracranial surgery (100%). Central venous lines were placed in 63.3% of cases. Moderate intraoperative hypothermia was carried out in 12.8% of the procedures, especially during vascular supratentorial and infratentorial surgery. A neuromuscular blockade during surgery was implemented in 74.1% of patients. Assessment of the neuromuscular junction was performed in 59.2% of cases, 76.7% of patients were immediately extubated in the operating room. 84.7% of these patients were directly transferred to a monitoring ward or an intensive care unit (ICU) and 55.1% of ventilated patients were transferred directly to an ICU. CONCLUSION: The data demonstrate that many aspects of anesthesia management during elective intracranial surgery vary between European institutions. The data also suggest that a broad consensus exists regarding the implementation of total intravenous anesthesia, airway management (endotracheal intubation), the implementation of urinary catheters, large bore peripheral venous lines and the broad availability of cross-matched red blood cell concentrates. Nevertheless, anesthesia management (e.g. central venous catheterization, moderate hypothermia, neuromuscular monitoring) is still handled differently across many European institutions. A lack of standardized guidelines defining anesthetic management in patients undergoing intracranial procedures could explain this variability. Further studies could help establish optimal anesthesia management for these patients. This in turn could help in the development of national and international guidelines and SOPs which could define optimal management strategies for intracranial procedures.

Head-to-head comparison of two continuous glucose monitoring systems on a cardio-surgical ICU.

In critical illness hypo-and hyperglycemia have a negative influence on patient outcome. Continuous glucose monitoring (CGM) could help in early detection of hypo-and hyperglycemia. A requirement for these new methods is an acceptable accuracy and precision in clinical practice. In this pilot study we prospectively evaluated the accuracy and precision of two CGM sensors (subcutaneous sensor: Sentrino®, Medtronic and intravasal sensor: Glucoclear®, Edwards) in 20 patients on a cardio-surgical ICU in a head to head comparison. CGM data were recorded for up to 48 h and values were compared with blood-gas-analysis (BGA) values, analysed with Bland-Altman-plots and color-coded surveillance error-grids. Shown are means ± standard deviations. In total 270/255 intravasal/subcutaneous pairs with BGA-values were analysed. The average runtime of the sensors was 28.4 ± 6.4 h. Correlation with BGA values yielded a correlation coefficient of 0.76 (subcutaneous sensor) and 0.92 (intravasal sensor). The Bland Altman Plots revealed an accuracy of 2.5 mg/dl, and a precision of + 43.0 mg/dl to - 38.0 mg/dl (subcutaneous sensor) and an accuracy of - 6.0 mg/dl, and a precision of + 12.4 mg/dl to - 24.4 mg/dl (intravasal sensor). No severe hypoglycemic event, defined as BG level below 40 mg/dl, occurred during treatment. Both sensors showed good accuracy in comparison to the BGA values, however they differ regarding precision, which in case of the subcutaneous sensor is considerable high.

Comparison of blood pressure monitoring by applanation tonometry and invasively assessed blood pressure in cardiological patients.

The aim of this study was to evaluate the accuracy and precision of non-invasive continuous blood pressure measurement by applanation tonometry (AT) in awake or anaesthetised cardiological intensive care patients. Patients suffering from highly impaired left ventricular function atrial fibrillation or severe aortic valve stenosis were included into the study. Arterial blood pressure was recorded by applanation tonometry (T-Line 400, Tensys Medical®, USA) and an arterial line in awake or anaesthetised patients. Discrepancies in mean (MAP), systolic (SAP), and diastolic (DAP) arterial pressure between the two methods were assessed as bias, limits of agreement and percentage error respectively. In 31 patients a total of 27,900 measurements were analyzed. The concordance correlation coefficient was 0.23, 0.45 and 0.06 for MAP, SAP and DAP, respectively. For all patients bias for MAPAT compared to MAPAL was 14.96 mmHg (SAPAT 4.51 mmHg; DAPAT 19.12 mmHg) with limits of agreement for MAPAT of 46.25 and - 16.33 mm Hg (SAPAT 48.00 and - 38.98 mmHg; DAPAT 50.12 and - 11.89 mmHg). Percentage error for MAPAT was 56.8% (42.7% for SAPAT; 75.2% for DAPAT). We conclude that the AT method is not reliable in ICU patients with severe cardiac comorbidities.

[Certain and controversial components of "rapid sequence induction"]. / Sichere und kontroverse Komponenten der "rapid sequence induction".

Rapid sequence induction (RSI) is a specific technique for anesthesia induction, which is performed in patients with an increased risk for pulmonary aspiration (e.g. intestinal obstruction, severe injuries and cesarean section). The incidence of acute respiratory distress syndrome (ARDS) is very low but 10-30% of anesthesia-related deaths are caused by the consequences of ARDS. The classical RSI with its main components (i.e. head-up position, avoidance of positive pressure ventilation and administration of succinylcholine) was published nearly 50 years ago and has remained almost unchanged. The modified RSI consists of mask ventilation before endotracheal intubation is performed or the use of non-depolarizing muscle relaxants. Succinylcholine 1.0 mg/kg or rocuronium 1.0-1.2 mg/kg should be administered to achieve excellent intubation conditions. The use of cricoid pressure was a cornerstone of RSI after its introduction in 1961; however, after controversial discussions in recent years, cricoid pressure has lost its importance. Before surgery gastric emptying with a nasogastric tube is mandatory in patients with ileus and passage or defecation disorders.

[Influence of rocuronium dose on the effectiveness of mask ventilation : A prospective, randomized clinical trial]. / Der Einfluss der Rocuroniumdosis auf die Effektivität der Maskenbeatmung : Eine prospektive, randomisierte, klinische Studie.

BACKGROUND: Mask ventilation could improve after administration of muscle relaxants if there is a functional obstruction of the airway, such as laryngospasm, vocal cord closure or opioid-induced muscle rigidity. On the other hand, muscle relaxants could worsen mask ventilation because they induce upper airway collapse; however, clinical studies showed that rocuronium (Roc) improved mask ventilation or it remained unchanged. In most cases Roc 0.06 mg/kgBW was used. OBJECTIVE: The optimal dose of Roc has not been studied; therefore, we studied the quality of mask ventilation with three different doses of Roc (0.3, 0.6 and 0.9 mg/kgBW) and compared them with a control group receiving saline. MATERIAL AND METHODS: In this prospective clinical trial 200 patients were randomized into 4 groups: NaCl (saline), Roc03 (Roc 0.3 mg/kgBW), Roc06 (Roc 0.6 mg/kgBW) and Roc09 (Roc 0.9 mg/kgBW). Mask ventilation was performed to reach a tidal volume (TV) of >5.0 ml/kgBW; maximum ventilation peak pressure (ppeak) was limited to 25 mbar. If this TV was not reached, mask ventilation was improved by better mask position, head position or/and usage of a Guedel tube (oropharyngeal airway). During mask ventilation ppeak and TV were recorded and the quality of mask ventilation was assessed with the Han and Warters scores. The quality of mask ventilation between the four groups was compared for all patients and a subgroup analysis was performed for patients of the study groups, who had to be ventilated with a Guedel tube and for obese patients (body mass index ≥26 kg/m2). A sample size calculation revealed that at least 38 patients were necessary for each group to detect a statistically significant difference between groups; it was assumed that Roc improved the efficacy of mask ventilation by 20% compared to saline (α = 0.05, 1-ß = 0.8). RESULTS: The administration of Roc significantly improved the TV/ppeak ratio compared to saline (p = 0.04); however, this effect was irrespective of the dose. In patients who were ventilated with the Guedel tube the TV/ppeak ratio increased after Roc03 (p ≤ 0.01) and after Roc06 (p < 0.02) compared to the saline group. In obese patients who were ventilated with the Guedel tube the TV/ppeak ratio increased after Roc03 (p ≤ 0.01), after Roc06 (p = 0.03) and after Roc09 (p = 0.02) compared to the saline group. There were no significant differences between the Roc groups; however, the effect was more pronounced in the Roc03 patients compared to the other Roc groups. The Han and Warters scores were not significantly different between the Roc groups and the saline group. CONCLUSION: The efficacy of mask ventilation was equal or improved after administration of Roc but did not become worse. Patients who were ventilated with a Guedel tube had higher TV/ppeak ratios after Roc03 and Roc06 compared to saline. Higher dosages (>Roc06), however, had no advantages concerning quality of mask ventilation. In obese patients who had to be ventilated with a Guedel tube, Roc also improved the efficacy of mask ventilation. We conclude that administration of Roc is effective in improving mask ventilation and this effect was seen after 30-60 s even after Roc03.

Impact of dexamethasone in patients with aneurysmal subarachnoid haemorrhage.

BACKGROUND AND PURPOSE: The role of corticosteroids in the treatment of patients with aneurysmal subarachnoid haemorrhage (SAH) has remained controversial for decades. Recent studies have suggested that the administration of corticosteroids in SAH patients is associated with favourable outcomes. Given their significant adverse effects, it is essential to identify those patients who will benefit from treatment with corticosteroids. METHODS: A retrospective analysis of a prospectively collected cohort (n = 306) with SAH who were treated by microsurgical clipping or endovascular intervention was performed. The role of dexamethasone administration was analysed with regard to clinical conditions and SAH-related complications. Outcome was assessed at discharge and during follow-up using the Glasgow Outcome Scale (GOS). RESULTS: Patients treated with dexamethasone presented with more episodes of hyperglycaemia (P < 0.001), more overall infections (P < 0.001) and more ventriculostomy-related infections (P = 0.004). Multivariate analysis demonstrated that treatment with dexamethasone was associated with an unfavourable outcome at discharge (GOS 1-3) [odds ratio (OR) 2.814, 95% confidence interval (CI) 1.440-5.497, P = 0.002]. In the subgroup of microsurgically treated patients, dexamethasone administration was associated with a favourable outcome at follow-up (OR 0.193, 95% CI 0.06-0.621, P = 0.006). A higher risk for unfavourable outcome (OR 3.382, 95% CI 1.67-6.849, P = 0.001) at discharge was observed in endovascularly treated patients who received dexamethasone but this had no impact on the outcome at follow-up. CONCLUSIONS: Treatment with dexamethasone seems to be associated with a risk reduction for an unfavourable outcome in those patients who underwent microsurgical clipping. Despite an increased frequency of adverse effects, glucocorticoids may have a potential benefit in this specific surgical subgroup compared to endovascularly treated SAH patients.

Post-induction hypotension and early intraoperative hypotension associated with general anaesthesia.

BACKGROUND: We hypothesized that different phases of intraoperative hypotension should be differentiated because of different underlying causative mechanisms. We defined post-induction hypotension (PIH; i.e. arterial hypotension occurring during the first 20 min after anaesthesia induction) and early intraoperative hypotension (eIOH; i.e. arterial hypotension during the first 30 min of surgery). METHODS: In this retrospective study, we included 2037 adult patients who underwent general anaesthesia. Arterial hypotension was defined as a systolic arterial blood pressure (SAP) <90 mm Hg or a need for norepinephrine infusion at > 6 µg min -1 at least once during the phases of PIH and eIOH. Multivariate logistic regression analysis was used to test for association of clinical factors with PIH and eIOH. RESULTS: Independent variables significantly related to PIH were pre-induction SAP [odds ratio (OR) 0.97 (95% confidence interval 0.97-0.98)], age [OR 1.03 (1.02-1.04)], and emergency surgery [OR 1.75 (1.20-2.56); P <0.01 each]. Pre-induction SAP [OR 0.99 (0.98-0.99), P <0.01], age [OR 1.02 (1.02-1.03), P <0.01], emergency surgery [OR 1.83 (1.28-2.62), P <0.01], supplementary administration of spinal or epidural anaesthetic techniques [OR 3.57 (2.41-5.29), P <0.01], male sex [OR 1.41 (1.12-1.79), P <0.01], and ASA physical status IV [OR 2.18 (1.19-3.99), P =0.01] were significantly related to eIOH. CONCLUSIONS: We identified clinical factors associated with PIH and eIOH. The use of these factors to estimate the risk of PIH and eIOH might allow the avoidance or timely treatment of hypotensive episodes during general anaesthesia.

Electrical impedance tomography for non-invasive assessment of stroke volume variation in health and experimental lung injury.

BACKGROUND: Functional imaging by thoracic electrical impedance tomography (EIT) is a non-invasive approach to continuously assess central stroke volume variation (SVV) for guiding fluid therapy. The early available data were from healthy lungs without injury-related changes in thoracic impedance as a potentially influencing factor. The aim of this study was to evaluate SVV measured by EIT (SVVEIT) against SVV from pulse contour analysis (SVVPC) in an experimental animal model of acute lung injury at different lung volumes. METHODS: We conducted a randomized controlled trial in 30 anaesthetized domestic pigs. SVVEIT was calculated automatically analysing heart-lung interactions in a set of pixels representing the aorta. Each initial analysis was performed automatically and unsupervised using predefined frequency domain algorithms that had not previously been used in the study population. After baseline measurements in normal lung conditions, lung injury was induced either by repeated broncho-alveolar lavage (n=15) or by intravenous administration of oleic acid (n=15) and SVVEIT was remeasured. RESULTS: The protocol was completed in 28 animals. A total of 123 pairs of SVV measurements were acquired. Correlation coefficients (r) between SVVEIT and SVVPC were 0.77 in healthy lungs, 0.84 after broncho-alveolar lavage, and 0.48 after lung injury from oleic acid. CONCLUSIONS: EIT provides automated calculation of a dynamic preload index of fluid responsiveness (SVVEIT) that is non-invasively derived from a central haemodynamic signal. However, alterations in thoracic impedance induced by lung injury influence this method.

Perioperative assessment of regional ventilation during changing body positions and ventilation conditions by electrical impedance tomography.

BACKGROUND: Lung-protective ventilation is claimed to be beneficial not only in critically ill patients, but also in pulmonary healthy patients undergoing general anaesthesia. We report the use of electrical impedance tomography for assessing regional changes in ventilation, during both spontaneous breathing and mechanical ventilation, in patients undergoing robot-assisted radical prostatectomy. METHODS: We performed electrical impedance tomography measurements in 39 patients before induction of anaesthesia in the sitting (M1) and supine position (M2), after the start of mechanical ventilation (M3), during capnoperitoneum and Trendelenburg positioning (M4), and finally, in the supine position after release of capnoperitoneum (M5). To quantify regional changes in lung ventilation, we calculated the centre of ventilation and 'silent spaces' in the ventral and dorsal lung regions that did not show major impedance changes. RESULTS: Compared with the awake supine position [2.3% (2.3)], anaesthesia and mechanical ventilation induced a significant increase in silent spaces in the dorsal dependent lung [9.2% (6.3); P<0.05]. Capnoperitoneum and the Trendelenburg position led to a significant increase in such spaces [11.5% (8.9)]. Silent space in the ventral lung remained constant throughout anaesthesia. CONCLUSION: Electrical impedance tomography was able to identify and quantify on a breath-by-breath basis circumscribed areas, so-called silent spaces, within healthy lungs that received little or no ventilation during general anaesthesia, capnoperitoneum, and different body positions. As these silent spaces are suggestive of atelectasis on the one hand and overdistension on the other, they might become useful to guide individualized protective ventilation strategies to mitigate the side-effects of anaesthesia and surgery on the lungs.

Is applanation tonometry a reliable method for monitoring blood pressure in morbidly obese patients undergoing bariatric surgery?

BACKGROUND: The aim of this study was to evaluate the validity of non-invasive continuous BP measurement by applanation tonometry in morbidly obese patients undergoing bariatric surgery. METHODS: Arterial blood pressure (AP) was recorded intraoperatively both by applanation tonometry (AT) (T-Line 200pro, Tensys Medical(®), USA) and an arterial line (AL) after radial cannulation in obese patients undergoing bariatric surgery. Discrepancies between the two methods were assessed as bias, limits of agreement and percentage error. Mean, systolic, and diastolic arterial pressures were assessed (MAP, SAP, DAP respectively). Trending ability was assessed by concordance based on four-quadrant plotting. RESULTS: Mean (sd) BMI of the 28 patients was 49.4 (9.7 kg m(-2)). A total of 201 907 time points were available for analysis. Bias for MAPAT compared with MAPAL was +3.97 mm Hg (SAPAT +3.45 mm Hg; DAPAT +3.66 mm Hg) with limits of agreement for MAPAT of -14.47 and +22.41 mm Hg (SAPAT -22.0 and +28.9 mm Hg; DAPAT -15.7 and +23.1 mm Hg). Percentage error for MAPAT was 23.5% (23.4% for SAPAT; 30.5% for DAPAT). Trending ability for MAP, SAP, and DAP revealed a concordance of 0.74, 0.72, and 0.71, respectively. CONCLUSIONS: Continuous BP assessment by applanation tonometry is feasible in morbidly obese patients undergoing bariatric surgery. However, despite a low mean difference, 95% limits of agreement and trending ability indicate that the technology needs to be improved further, before being recommended for routine use in this group of patients.

Noninvasive continuous cardiac output monitoring in perioperative and intensive care medicine.

The determination of blood flow, i.e. cardiac output, is an integral part of haemodynamic monitoring. This is a review on noninvasive continuous cardiac output monitoring in perioperative and intensive care medicine. We present the underlying principles and validation data of the following technologies: thoracic electrical bioimpedance, thoracic bioreactance, vascular unloading technique, pulse wave transit time, and radial artery applanation tonometry. According to clinical studies, these technologies are capable of providing cardiac output readings noninvasively and continuously. They, therefore, might prove to be innovative tools for the assessment of advanced haemodynamic variables at the bedside. However, for most technologies there are conflicting data regarding the measurement performance in comparison with reference methods for cardiac output assessment. In addition, each of the reviewed technology has its own limitations regarding applicability in the clinical setting. In validation studies comparing cardiac output measurements using these noninvasive technologies in comparison with a criterion standard method, it is crucial to correctly apply statistical methods for the assessment of a technology's accuracy, precision, and trending capability. Uniform definitions for 'clinically acceptable agreement' between innovative noninvasive cardiac output monitoring systems and criterion standard methods are currently missing. Further research must aim to further develop the different technologies for noninvasive continuous cardiac output determination with regard to signal recording, signal processing, and clinical applicability.