[Delirium in intensive care patients : A multiprofessional challenge]. / Delir beim Intensivpatienten : Eine multiprofessionelle Herausforderung.

Delirium is the most common form of cerebral dysfunction in intensive care patients and is a medical emergency that must be avoided or promptly diagnosed and treated. According to current knowledge the development of delirium seems to be caused by an interplay between increased vulnerability (predisposition) and simultaneous exposure to delirogenic factors. Since delirium is often overlooked in the clinical routine, a continuous screening for delirium should be performed. Due to the close connection between delirium, agitation and pain, sedation and analgesia must be evaluated at least every 8 h analogous to delirium screening. According to current knowledge, a multifactorial and multiprofessional approach is favored in the prevention and treatment of delirium. Non-pharmaceutical interventions through early mobilization, reorientation, sleep improvement, adequate pain therapy and avoidance of polypharmacy are of great importance. Depending on the clinical picture, different substances are used in symptom-oriented drug treatment of delirium. In order to achieve these diagnostic and therapeutic goals, an interdisciplinary treatment team consisting of intensive care, intensive care physicians, ward pharmacists, physiotherapists, nutrition specialists and psychiatrists is necessary in order to meet the requirements of the patient and their relatives.

Risks and prevention of surgical fires : A systematic review.

Surgically induced fire is a life-threatening hazard; this topic has received little attention, although only 3 factors, the so-called fire triad, are needed for surgical fires to occur: an oxidizer, fuel and an ignition source. This systematic review aims to determine the impact of each component and to delegate every staff member an area of responsibility, thus ensuring patient health through prevention or protection. The trial was registered in Prospero CRD42018082656. A database search of eligible, preferably evidence-based studies was conducted. The Robins-I tool for assessing the risk of bias revealed a moderate risk of bias. Due to insufficient data, the main findings of these studies could not be summarized through a quantitative synthesis; therefore, a qualitative synthesis is outlined. The results are summarized according to the roles of the fire triad and discussed. (1) Role of the oxidizer: oxygen is the key component of the triad. Safe oxygen delivery is important. An oxygen-enriched environment (ORE) is caused by draping and is preferably prevented by suctioning. Fuel characteristics are affected by varying oxygen concentrations. (2) Role of the ignition source: electrocauterization is the most common ignition source, followed by lasers. Less common ignition sources include fiberoptic cables and preparative solutions, petrol or acetone. (3) Role of the fuel: surgical drapes are one of the most common fuels for surgical fires followed by the patient's hair and skin. Skin preparation solutions are among the less common fuels. Many fire-resistant materials have been tested that do not remain fire resistant in ORE. It was concluded that the main problem is defining the real extent of this hazard. Exact numbers and exact condition protocols are needed; therefore, standardized registration of every fire and future studies with much evidence are needed. Immediate prevention consists of close attention to patient safety to prevent surgical fires from happening.

[Update on muscle relaxation : What comes after succinylcholine, rocuronium and sugammadex?] / Update Muskelrelaxation : Was kommt nach Succinylcholin, Rocuronium und Sugammadex?

Due to the great advantages, it is not possible to imagine current practice in anesthesia without the adminstration of muscle relaxants. For a long time the administration of succinylcholine for rapid sequence induction (RSI) was considered to be the state of the art for patients at risk for aspiration. The favorable characteristics are, however, accompanied by many, sometimes severe side effects. Due to the development of non-depolarizing muscle relaxants, in particular rocuronium in combination with sugammadex, there is the possibility to achieve a profile of action similar to succinylcholine with low side effects. After the introduction of sugammadex onto the market, further substances were conceived, which enable a complete encapsulation of muscle relaxants. Calabadion is a very promising new substance for the antagonization of muscle relaxants, which can antagonize the action of steroid as well as benzylisoquinoline types. In the USA new muscle relaxants are currently being tested, which have a rapid onset and the effect can be reversed by L­cysteine. One of the most promising substances is gantacurium, which is currently being tested in the USA in phase III trials. It remains to be seen whether these muscle relaxants, which are not yet on the market and drugs for reversal of neuromuscular blockade have the potential to become a real alternative to the combination of rocuronium and sugammadex.

[Management of delirium in the intensive care unit : Non-pharmacological therapy options]. / Delirmanagement in der Intensivmedizin : Nichtmedikamentöse Therapieoptionen.

BACKGROUND: Non-pharmacological intervention strategies are used in the prevention and therapy of delirium. OBJECTIVES: Investigation of the effectiveness of non-pharmacological therapy options. METHODS: Analysis of review articles and studies in order to make recommendations for the clinical practice. RESULTS: Reorientation, promotion of mental activities, adequate communication, early physiotherapy and avoidance of both polypharmacy and sleep deprivation have a high impact on the prevention and therapy of delirium. CONCLUSION: Non-pharmacological intervention strategies are very important in the prevention and therapy of delirium.

Intubation performance using different laryngoscopes while wearing chemical protective equipment: a manikin study.

OBJECTIVES: This study aimed to compare visualisation of the vocal cords and performance of intubation by anaesthetists using four different laryngoscopes while wearing full chemical protective equipment. SETTING: Medical simulation center of a university hospital, department of anaesthesiology. PARTICIPANTS: 42 anaesthetists (15 females and 27 males) completed the trial. The participants were grouped according to their professional education as anaesthesiology residents with experience of <2 years or <5 years, or as anaesthesiology specialists with experience of >5 years. INTERVENTIONS: In a manikin scenario, participants performed endotracheal intubations with four different direct and indirect laryngoscopes (Macintosh (MAC), Airtraq (ATQ), Glidescope (GLS) and AP Advance (APA)), while wearing chemical protective gear, including a body suit, rubber gloves, a fire helmet and breathing apparatus. PRIMARY AND SECONDARY OUTCOME MEASURES: With respect to the manikin, setting time to complete 'endotracheal intubation' was defined as primary end point. Glottis visualisation (according to the Cormack-Lehane score (CLS) and impairments caused by the protective equipment, were defined as secondary outcome measures. RESULTS: The times to tracheal intubation were calculated using the MAC (31.4 s; 95% CI 26.6 to 36.8), ATQ (37.1 s; 95% CI 28.3 to 45.9), GLS (35.4 s; 95% CI 28.7 to 42.1) and APA (23.6 s; 95% CI 19.1 to 28.1), respectively. Intubation with the APA was significantly faster than with all the other devices examined among the total study population (p<0.05). A significant improvement in visualisation of the vocal cords was reported for the APA compared with the GLS. CONCLUSIONS: Despite the restrictions caused by the equipment, the anaesthetists intubated the manikin successfully within adequate time. The APA outperformed the other devices in the time to intubation, and it has been evaluated as an easily manageable device for anaesthetists with varying degrees of experience (low to high), providing good visualisation in scenarios that require the use of chemical protective equipment.

Insular infarct size but not levosimendan influenced myocardial injury triggered by cerebral ischemia in rats.

Cerebral injuries can trigger stress-related cardiomyopathy. The extent of cerebral injury and the involvement of the insular cortex influence the incidence and extent of myocardial injury (MI), and drugs with proven neuroprotective and cardioprotective properties such as levosimendan might be beneficial. This hypothesis was addressed in a rat model of transient middle cerebral artery occlusion. Transient brain ischemia was induced for 60 min by intraluminal occlusion of the middle cerebral artery in 40 male Wistar rats. Treatment with levosimendan (24 µg/kg) was started briefly before reperfusion. Hemodynamic parameters were recorded and cerebral and MI quantified after 24 h. Levosimendan treatment significantly reduced cerebral infarct size in the cortex, but not in the striatal and insular regions. However, its effects on survival (28 vs. 45%), incidence of MI (8 vs. 33%) as indicated by a troponin I (sTnI) threshold of 4.8 µg/L and large insular infarcts of ≥10 mm(3) (23 vs. 50%) failed to reach statistical significance. Blood pressure demonstrated significant differences related to insular infarct size during reperfusion. Levosimendan demonstrated no relevant effects on markers of MI (sTnI = 1.5 ± 2.8 vs. 5.3 ± 7.2 µg/L, P = 0.121). Insular infarct size could be identified as the only predictor of MI (odds ratio = 1.86, P = 0.037). In conclusion, the current investigation confirmed insular infarct size as a predictor of MI and source of hemodynamic compromise, but failed to demonstrate an effect of levosimendan on MI trigged by brain ischemia. A hardly protectable insular region might explain this.

A laboratory comparison of the performance of the buddy lite™ and enFlow™ fluid warmers.

Maintenance of normothermia is crucial to avoid patient morbidity. Newly released fluid warming devices have become smaller in size, but this change might impair efficacy. We performed an evaluation of the buddy lite™ and enFlow™ fluid warmers. We measured inflow and outlet temperatures of the devices at flow rates between 25 and 100 ml.min(-1) using saline at room temperature or cooled to 10 °C. At a flow rate of 25 ml.min(-1) , the outlet temperature of the buddy lite was significantly higher than that of the enFlow (p < 0.0001), but at flow rates of 75 and 100 ml.min(-1) , it was significantly lower (p < 0.0001). This pattern was the same for both room temperature and cooled saline. There was a significant drop in the temperature of saline along the length of a 1-m outflow tube. We conclude that both devices provide effective fluid warming at a low flow rate, although the heating capability of the buddy lite is limited at high flow rates.

Effect of anesthesia and cerebral blood flow on neuronal injury in a rat middle cerebral artery occlusion (MCAO) model.

Middle cerebral artery occlusion (MCAO) models have become well established as the most suitable way to simulate stroke in experimental studies. The high variability in the size of the resulting infarct due to filament composition, rodent strain and vessel anatomy makes the setup of such models very complex. Beside controllable variables of homeostasis, the choice of anesthetics and the grade of ischemia and reperfusion played a major role for extent of neurological injury. Transient MCAO was induced during either isoflurane or ketamine/xylazine (ket/xyl) anesthesia with simultaneously measurement of cerebral blood flow (CBF) in 60 male Wistar rats (380-420 g). Neurological injury was quantified after 24 h. Isoflurane compared with ket/xyl improved mortality 24 h after MCAO (10 vs. 50 %, p = 0.037) and predominantly led to striatal infarcts (78 vs. 18 %, p = 0.009) without involvement of the neocortex and medial caudoputamen. Independent of anesthesia type, cortical infarcts could be predicted with a sensitivity of 67 % and a specificity of 100 % if CBF did not exceed 35 % of the baseline value during ischemia. In all other cases, cortical infarcts developed if the reperfusion values remained below 50 %. Hyperemia during reperfusion significantly increased infarct and edema volumes. The cause of frequent striatal infarcts after isoflurane anesthesia might be attributed to an improved CBF during ischemia (46 ± 15 % vs. 35 ± 19 %, p = 0.04). S-100ß release, edema volume and upregulation of IL-6 and IL-1ß expression were impeded by isoflurane. Thus, anesthetic management as well as the grade of ischemia and reperfusion after transient MCAO demonstrated important effects on neurological injury.

Air elimination capability in rapid infusion systems.

Pressure infusion devices are used in clinical practice to apply large volumes of fluid over a short period of time. Although air infusion is a major complication, they have limited capability to detect and remove air during pressure infusion. In this investigation, we tested the air elimination capabilities of the Fluido(®) (The Surgical Company), Level 1(®) (Level 1 Technologies Inc.) and Ranger(®) (Augustine Medical GmbH) pressure infusion devices. Measurements were undertaken with a crystalloid solution during an infusion flow of 100, 200, 400 and 800 ml.min(-1). Four different volumes of air (25, 50, 100 and 200 ml) were injected as boluses in one experimental setting, or infused continuously over the time needed to perfuse 2 l saline in the other setting. The perfusion fluid was collected in an airtight infusion bag and the amount of air obtained in the bag was measured. The delivered air volume was negligible and would not cause any significant air embolism in all experiments. In our experimental setting, we found, during high flow, an increased amount of uneliminated air in all used devices compared with lower perfusion flows. All tested devices had a good air elimination capability. The use of ultrasonic air detection coupled with an automatic shutoff is a significant safety improvement and can reliably prevent accidental air embolism at rapid flows.

Pulse oximetry during intraaortic balloon pump application.

BACKGROUND: Pulse oximeters are multiple used devices in anaesthesiology and intensive care medicine and must provide reliable data during various conditions of signal interference, including light, motion and reduced perfusion. The aim of this study was to evaluate the reliability of different new-generation pulse oximeters during intraaortic balloon pump (IABP) therapy. METHODS: In the experimental setting, the validity of three pulse oximetry technologies (Masimo Radical 7, Nellcor N-600 and Datex Ohmeda TruSat) was evaluated in patients with IABP treatment. Arterial blood gas analysis (BGA-SaO2) data were compared with the pulse oximetric values (SpO2) during 1:1, 1:2 and 1:3 support ratio. RESULTS: The mean differences (bias) during 1:1, 1:2 and 1:3 IABP support between BGA-SaO2 and Datex-SpO2 were 3.38% [95% confidence intervals (CI):±1.39%], 1.41% (95% CI 1.14%) and 2.10% (95% CI:±0.94%), respectively. Between BGA-SaO2 and Nellcor-SpO2, a bias of 0.77% (95% CI:±0.46%), 0.85% (95% CI:±0.40%) and 0.59% (95% CI:±0.38%) was found. In the comparison of BGA-SaO2 and Masimo-SpO2, a bias of 0.58% (95% CI:±0.56%), 0.19% (95% CI:±0.40%) and -0.01% (95% CI:±0.43%) was found, respectively. CONCLUSIONS: In patients with IABP support, the pulse oximetric values of the Masimo Radical 7 are accurate in 1:2 and 1:3 support ratio compared with blood gas analysis. In these support ratios, the Masimo Radical 7 is superior to the Nellcor N-600. The Datex Ohmeda TruSat showed a significant difference between the measured pulse oximetric values and blood gas analysis in all support ratios.

Postoperative cognitive dysfunction: Incidence and prophylaxis.

The incidence of postoperative cognitive dysfunction (POCD) is often underestimated and not intuitively present by many anesthetists. POCD often occurs in the elderly but is also seen in younger patients. The incidence of POCD 1 week after non-cardiac surgery covers a span between 19-41% in patients older than 18 years. An increased POCD rate (10%) 3 months after surgery is only detected in patients older than 60 years. The occurrence of POCD is associated with an increased mortality rate, jet the etiology is mainly unknown despite enormous research efforts. The age of the patient is one of the main risk factors for the development of POCD. Data on how to avoid POCD are limited. However, the maintenance of homoeostasis is an important cornerstone of prophylaxis.

Comparison of electrical velocimetry and thermodilution techniques for the measurement of cardiac output.

AIM: To compare a new method of non-invasive determination of cardiac output based on electrical velocimetry (EV-CO) with invasive thermodilution methods. METHODS: Fifty critically ill patients were enrolled into the study. EV-CO was compared with cardiac output measured by a pulmonary artery catheter (PA-CO) in one group (n= 25) and by a femoral artery catheter (PiCCO-CO) in a second group (n= 25), by simultaneous measurements. Standard electrocardiography electrodes were used for non-invasive measurements, and EV-CO was calculated using the Bernstein-Osypka equation. The invasive measurements of PA-CO and PiCCO-CO were made by the injection of iced 0.9% saline and the recording of thermodilution curves. RESULTS: The precision values of EV-CO, PA-CO and PiCCO-CO measurements were +/- 0.46 [95% confidence interval (95% CI), +/- 0.06], +/- 0.57 (95% CI, +/- 0.09) and +/- 0.48 l/min (95% CI, +/- 0.08 l/min), respectively. The mean differences between EV-CO and PA-CO or PiCCO-CO were -0.05 +/- 0.71 and 0.22 +/- 0.78 l/min, respectively. The lower and upper limits of agreement for the comparison of EV-CO with PA-CO were -1.47 and 1.37 l/min (95% CI, +/- 0.25 l/min), respectively. In the comparison of EV-CO and PiCCO-CO, lower and upper limits of -1.34 and 1.78 l/min (95% CI, +/- 0.27 l/min) were found. The percentage errors between EV-CO and PA-CO or PiCCO-CO were 26.5% and 26.4%, respectively. CONCLUSIONS: The values of cardiac output were statistically comparable between the groups. Therefore, electrical velocimetry is a suitable method to evaluate haemodynamic variables with clinically acceptable accuracy.

Effects of feeding a standard diet on duodenal impedancometry in pigs.

The effects of gastric feeding on intestinal motility are still under debate. In order to better define the character of the contractile activity in fed and fasting states, we used the impedance technique to investigate the duodenal time periods of the migrating motor complex (MMC) and the interdigestive phases I-III. During general anaesthesia, pigs (32-40 kg) were instrumented with a luminal impedance catheter into the proximal duodenum in fasting (n = 6) and fed states (n = 6, Muskator, 400 g, Muskator-Werk, Düsseldorf, Germany). Duodenal motility was recorded continuously for 4 h, which made it possible to determine the length of interdigestive phases I-III and the MMC cycle. Differences between the groups were compared by using the Wilcoxon Rank-Sum Test. Feeding patterns were only found in pigs in the fed state. The subsequent MMC cycle length was shortened by 34% (p = 0.007) which was due to a shortened phase I of the MMC cycle (p = 0.014). While phase II seemed to be unaffected, phase III was prolonged by 31% after feeding had occurred (p = 0.012). The present study suggests that a standard maintenance diet disrupts the spontaneous MMC cycles by turning into fed pattern with the subsequent MMC cycle length being shortened. This was mainly due to a shortened phase I.