Anästhesiologische Risikoevaluation und rechtssichere Aufklärung per Telemedizin – Sind wir bereit für einen Paradigmenwechsel?

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Potenzial und Wirksamkeit eines telemedizinischen Rettungsassistenzsystems

Background

The demographic change and an increasing multimorbidity of patients represent increasing challenges for the adequate prehospital treatment of emergency patients. The incorporation of supplementary telemedical concepts and systems can lead to an improved guideline-conform treatment. Beneficial evidence of telemedical procedures is only known for isolated disease patterns; however, no mobile telemedical concept exists which is suitable for use in the wide variety of different clinical situations.

Aim

This article presents a newly developed and evaluated total telemedical concept (TemRas) that encompasses organizational, medical and technical components. The use of intelligent and robust communication technology and the implementation of this add-on system allows the telemedical support of the rescue service for all emergencies.

Methods

After development of the telemedical rescue assistance system, which includes organizational, medical and technical components, a telemedical centre and six ambulances in five different districts in North-Rhine Westphalia were equipped with this new tool. During the evaluation phase of 1 year in the routine emergency medical service the rate of complications as well as differences between urban and rural areas were analyzed with respect to different target parameters.

Results

Between August 2012 and July 2013 a total of 401 teleconsultations were performed during emergency missions and 24 during secondary interhospital transfers. No complications due to teleconsultation were observed. The mean duration (±SD) of teleconsultations was longer in rural areas than in urban areas with 28.6±12.0?min vs. 25.5±11.1?min (p?<?0.0001). In 63.2?% of these missions administration of medications was delegated to the ambulance personnel (52.0?% urban vs. 73.6?% rural, p?<?0.0001). The severity of ailments corresponded to scores of III and VI in the National Advisory Committee for Aeronautics (NACA) classification.

Conclusion

Emergency medical care of patients with support by a telemedical system is technically feasible, safe for the patient and allows medical treatment independent of spatial availability of a physician in different emergency situations.

     

Verfügbarkeit,Performanz und Funktionalität telemetrisch übertragener Daten im Rettungsdienst

Background

Treatment of acute coronary syndrome and stroke in a prehospital setting benefits from telemedical procedures. This study investigates the availability and performance of telemedical data transfer and audiocommunication of different providers in an urban ambulance service using a commercial system.

Materials and methods

After approval of the local ethic committee, the monitor and defibrillation units of two emergency vehicles were equipped with subscriber identity module (SIM) cards from different providers. After initiation by a mobile call, data transmission of static (12-lead ECG) and dynamic (live vital) data from 120 ambulance calls where sent to a physician-staffed call center. The quality of data transfer and functionality were rated using a standardised (5-point scale) questionnaire.

Results

Of 120 trouble-free mobile call data transfers initiated, 117 were included. Transmission of the live vital data were significantly different (p = 0.0327) in quality of live vital data transmission between Telekom (median 2.0; range 1–4, 1 = no technical interference and 4 = teleconsultation impossible [5 = no documentation]) and Vodafone 2.5. Overall, the quality of the live data transmission was acceptable in 83?% of the cases. For the 12-lead ECG, data transmission was possible in 89?% (n = 32, Telekom) and 88?% (n = 36, Vodafone) of all transmissions.

Conclusion

The performance of static and dynamic telemedical data transmission in an urban area were significantly different for the two providers. Data transmission for telemedical use was possible in slightly less than 90?% of cases. Against the background that telemedical applications are being increasingly used, technical requirements to ensure availability and functionality in terms of patients safety are necessary.

     

Estimation of breathing rate in thermal imaging videos: a pilot study on healthy human subjects

Diverse studies have demonstrated the importance of monitoring breathing rate (BR). Commonly, changes in BR are one of the earliest and major markers of serious complications/illness. However, it is frequently neglected due to limitations of clinically established measurement techniques, which require attachment of sensors. The employment of adhesive pads or thoracic belts in preterm infants as well as in traumatized or burned patients is an additional paramount issue. The present paper proposes a new robust approach, based on data fusion, to remotely monitor BR using infrared thermography (IRT). The algorithm considers not only temperature modulation around mouth and nostrils but also the movements of both shoulders. The data of these four sensors/regions of interest need to be further fused to reach improved accuracy. To investigate the performance of our approach, two different experiments (phase A: normal breathing, phase B: simulation of breathing disorders) on twelve healthy volunteers were performed. Thoracic effort (piezoplethysmography) was simultaneously acquired to validate our results. Excellent agreements between BR estimated with IRT and gold standard were achieved. While in phase A a mean correlation of 0.98 and a root-mean-square error (RMSE) of 0.28 bpm was reached, in phase B the mean correlation and the RMSE hovered around 0.95 and 3.45 bpm, respectively. The higher RMSE in phase B results predominantly from delays between IRT and gold standard in BR transitions: eupnea/apnea, apnea/tachypnea etc. Moreover, this study also demonstrates the capability of IRT to capture varied breathing disorders, and consecutively, to assess respiratory function. In summary, IRT might be a promising monitoring alternative to the conventional contact-based techniques regarding its performance and remarkable capabilities.     

Expression analysis of the early chemokine response 4?h after in vitro traumatic brain injury

Objective and design  

The importance of cytokine- and chemokine-mediated neuroinflammation in the progress of brain injury is becoming increasingly evident. We investigated the early local cytokine and chemokine expression and the development of tissue injury after moderate mechanical hippocampus trauma.     

Neurological outcome after experimental lung injury

We examined the influences of acute lung injury and hypoxia on neurological outcome. Functional performance was assessed using a neurocognitive test and a neurologic deficit score (NDS) five days before. On experimental day, mechanically ventilated pigs were randomized to hypoxia only (HO group, n=5) or to acute lung injury (ALI group, n=5). Hemodynamics, respiratory mechanics, systemic cytokines and further physiologic variables were obtained at baseline, at the time of ALI, 2, 4 and 8h thereafter. Subsequently, injured lungs were recruited and animals weaned from the ventilator. Neurocognitive testing was re-examined for five days. Then, brains were harvested for neurohistopathology. After the experiment, neurocognitive performance was significantly worsened and the NDS increased in the ALI group. Histopathology revealed no significant differences. Oxygenation was comparable between groups although significantly higher inspiratory pressures occured after ALI. Cytokines showed a trend towards higher levels after ALI. Neurocognitive compromise after ALI seems due to a more pronounced inflammatory response and complex mechanical ventilation.     

Comparison of two in vivo microscopy techniques to visualize alveolar mechanics

Objective

In conventional in vivo microscopy, a three dimensional illustration of tissue is lacking. Concerning the microscopic analysis of the pulmonary alveolar network, surgical preparation of the thorax and fixation of the lung is required to place the microscope’s objective. These effects may have influence on the mechanical behaviour of alveoli. Relatively new methods exist for in vivo microscopy being less invasive and enabling an observation without fixation of the lung. The aim of this study was to compare a fibered confocal laser scanning microscopy (FCLSM) with optical coherence tomography (OCT) in a mouse and a rabbit model. Moreover, FCLSM was also used endoscopically in the rabbit model.

Methods

Smallest possible thoracic windows were excised at the lower margin of the upper right lung lobe and an interpleural catheter inserted before re-coverage with a transparent membrane foil. The OCT-scanner was positioned by a motor driven translation stage. The imaging was gated to endinspiratory plateau. For CLSM, Fluorescein 0.1% was given into the central venous streak line. The confocal probe with a diameter of 650 µm was carefully positioned at the very same lung region. Images were directly recorded real-time and the observed region qualitatively compared with FD-OCT images. Additionally, in the rabbit model, CLSM was used endoscopically under bronchoscopic sight control. In a post-processing analysis, images taken were analyzed and compared by using an “air index” (AI).

Results

In the mouse model, the very same region could be re-identified with both techniques. Concerning alveolar shape and size, qualitatively comparable images could be gained. The AI was 40.5% for the OCT and 40.1% for the CLSM images. In the rabbit, even an endoscopic view on alveoli was possible. Likewise AI was 43.2% for CLSM through the thoracic window and 43.6% from endoscopically. For the OCT an AI of 44.6% was analysed in the rabbit model.

Conclusions

Both FD-OCT and CLSM provide high-resolution images of alveolar structure giving depth information that is beneficial to conventional microscopy. CLSM also facilitates endoscopic view on alveoli being well comparable to images gained through a thoracic window.     

Fibrin patch in a pig model with blunt liver injury under severe hypothermia

Background

Rapid control of hemorrhage is one of the key aspects in trauma handling. To cope with bleeding, local hemostatic approaches are useful, along with surgical and systemic homostatic therapy. In this experimental study, we investigated the efficacy of a fibrinogen/thrombin containing collagen patch (TachoSil) in a coagulopathic pig model with blunt liver trauma under severe hypothermia.

Methods

Eighteen anesthetized pigs underwent hemodilution by exchanging 70% of the blood volume with Ringer Lactate solution and hydroxyethyl starch 130/0.4 (1:1). Ten minutes after induction of a grade III blunt liver trauma, the animals randomly received treatment with TachoSil (FT-patch, n = 9) or a collagen patch (Tachotop, control group, n = 9). Blood loss, hemodynamics, and coagulation parameters were observed for 2 h. To confirm the consistency of liver trauma, pathologic examination of the liver tissue was performed.

Results

Hypothermia (33.5°C ± 0.5°C) and hemodilution led to severe coagulopathy as measured by thromboelastometry and coagulation parameters. After trauma and patch application, thromboelastometry and coagulation parameters in the control group showed further deterioration compared with the stable parameters in the FT-patch group. The total blood loss was significantly reduced in the FT-patch group (FT-patch: 1195 mL; control group: 2495 mL; P < 0.001). Concordantly, the control animals were hemodynamically jeopardized to a higher degree. Microscopy confirmed a similar degree of liver injury.

Conclusions

Despite severe hypothermia and coagulopathy, TachoSil provided effective hemorrhage control in pigs with blunt liver injury. Therefore, TachoSil demonstrated usefulness as an additional early therapy in cases of uncontrolled bleeding following severe trauma.     

Contact-free monitoring of circulation and perfusion dynamics based on the analysis of thermal imagery

Acute circulatory disorders are commonly associated with systemic inflammatory response (SIRS) and sepsis. During sepsis, microcirculatory perfusion is compromised leading to tissue hypoperfusion and potentially to multiple organ dysfunction. In the present study, acute lung injury (ALI), one of the major causes leading to SIRS and sepsis, was experimentally induced in six female pigs. To investigate the progress of body temperature distribution, measurements with a long-wave infrared camera were carried out. Temperature centralization was evidenced during ALI owing to impairments of peripheral perfusion. In addition, statistical analysis demonstrated strong correlations between (a) standard deviation of the skin temperature distribution (SD) and shock index (SI) (p<0.0005), (b) SD and mean arterial pressure (MAP) (p<0.0005), (c) ΔT/Δx and SI (p<0.0005), as well as between (d) ΔT/Δx and MAP (p<0.0005). For clarification purposes, ΔT/Δx is a parameter implemented to quantify the spatial temperature gradient. This pioneering study created promising results. It demonstrated the capacity of infrared thermography as well as of the indexes, SD and ΔT/Δx, to detect impairments in both circulation and tissue perfusion.OCIS codes: (040.3060) Infrared, (170.1610) Clinical applications, (170.2655) Functional monitoring and imaging