Comparison of manually triggered ventilation and bag-valve-mask ventilation during cardiopulmonary resuscitation in a manikin model

Background

To compare a novel, pressure-limited, flow adaptive ventilator that enables manual triggering of ventilations (MEDUMAT Easy CPR, Weinmann, Germany) with a bag-valve-mask (BVM) device during simulated cardiac arrest.

Methods

Overall 74 third-year medical students received brief video instructions (BVM: 57 s, ventilator: 126 s), standardised theoretical instructions and practical training for both devices. Four days later, the students were randomised into 37 two-rescuer teams and were asked to perform 8 min of cardiopulmonary resuscitation (CPR) on a manikin using either the ventilator or the BVM (randomisation list). Applied tidal volumes (V_T), inspiratory times and hands-off times were recorded. Maximum airway pressures (P_max) were measured with a sensor connected to the artificial lung. Questionnaires concerning levels of fatigue, stress and handling were evaluated. V_T, pressures and hands-off times were compared using t-tests, questionnaire data were analysed using the Wilcoxon test.

Results

BVM vs. ventilator (mean ± SD): the mean V_T (408 ± 164 ml vs. 315 ± 165 ml, p = 0.10) and the maximum V_T did not differ, but the number of recorded V_T < 200 ml differed (8.1 ± 11.3 vs. 17.0 ± 14.4 ventilations, p = 0.04). P_max did not differ, but inspiratory times (0.80 ± 0.23 s vs. 1.39 ± 0.31 s, p < 0.001) and total hands-off times (133.5 ± 17.8 s vs. 162.0 ± 11.1 s, p < 0.001) did. The estimated levels of fatigue and stress were comparable; however, the BVM was rated to be easier to use (p = 0.03).

Conclusion

For the user group investigated here, this ventilator exhibits no advantages in the setting of simulated CPR and carries a risk of prolonged no-flow time.     

Methods for quantitative evaluation of alveolar structure during in vivo microscopy

In vivo fibred confocal laser scanning microscopy allows an evaluation of differences in alveolar mechanics between healthy and acutely injured lungs during mechanical ventilation. The aim of this study was to develop new methods for a quantitative analysis of microscopic images in a murine model of experimental acute lung injury (ALI) and to assess the methods' portability to a large animal model. Differences observed in ALI compared to healthy lungs were: reduction of air-filled areas, increase of heterogeneity and increase of shape irregularity. Three indices were developed: the volume air index (VAI) applies an integral over specific signal intensities, the heterogeneity index (HI) and the Heywood circularity index (CI) comprise variances in size and shape of alveolar structures. The differences between healthy and ALI conditions were found to be significant for all of the used indices (VAI: 0.648 vs. 0.443 (p < 0.05), HI: 0.852 vs. 1.348 (p < 0.001) and CI: 1.56 vs. 1.66 (p < 0.001)). The portability of these algorithms to a porcine model was confirmed reaching similar results (VAI: 0.50 vs. 0.35, p < 0.05; HI: 0.62 vs. 1.83, p < 0.05; CI: 1.56 vs. 1.63, p < 0.001). VAI, HI and CI may help to quantify microscopic images of changes in alveolar structure after experimental ALI.     

Analysis of regional compliance in a porcine model of acute lung injury

Lung protective ventilation in Acute Lung Injury (ALI) focuses on using low tidal volumes and adequate levels of positive end-expiratory pressure (PEEP). Identifying optimal pressure is difficult because pressure-volume (PV) relations differ regionally. Precise analysis demands local measurements of pressures and related alveolar morphologies. In a porcine model of surfactant depletion (n=24), we combined measuring static pressures with endoscopic microscopy and electrical impedance tomography (EIT) to examine regional PV loops and morphologic heterogeneities between healthy (control group; CON) and ALI lungs ventilated with low (LVT) or high tidal volumes (HVT). Quantification included indices for microscopy (Volume Air Index (VAI), Heterogeneity and Circularity Index), EIT analysis and calculation of regional compliances due to generated PV loops. We found that: (1) VAI decreased in lower lobe after ALI, (2) electrical impedance decreased in dorsal regions and (3) PV loops differed regionally. Further studies should prove the potentials of these techniques on individual respiratory settings and clinical outcome.     

Telemedizin

Background

To guarantee emergency care for the population in rural areas is challenging. The reduction of medical resources like hospital beds as well as the centralization off-hour panel doctors requires an increasing mobility of the residents in such areas and simultaneously leads to an increasing usage of the prehospital emergency medical service (EMS). Via implementation of telemedical concepts there is the opportunity to optimize the medical care of the rural population and to reduce the time interval until medical treatment begins.

Results

The application of modern information and communication technology in the setting of prehospital emergency care seems to be meaningful. This article describes different telemedical concepts of different diseases in a variety of healthcare sectors. The focus of this review is the concepts of an emergency physician for telemedical support of prehospital emergency care providers due to its multimodal concept.

Conclusion

In a situation with decreasing coverage of localized medical care in rural areas, telemedical solutions in combination with expansion of helicopter emergency medical service and optimization of the qualification of prehospital EMS personnel may be a reasonable approach.     

Qualitätsmanagement in der Regionalanästhesie am Beispiel des Regionalanästhesie Surveillance Systems (RASS)

Regional anesthesia and regional analgesia techniques with or without a continuous catheter are frequently utilized in all areas of modern anesthesiology. There are individual and economic benefits but also risks involved with those techniques. While the incidence of severe complications is rare and preventive action not always possible, the consequences can be detrimental especially with hematoma or abscess formation associated with central neuraxial blocks. Therefore, it is important to create national and international databases with large case numbers utilizing standardized definitions of complications in order to allow realistic risk assessment and early discovery of potential dangers and preventive actions. This article shows the integration of standardized codes from the Regional Anesthesia Surveillance System with a software tool to allow high-quality data acquisition and the building of a foundation for national and international data collection and analysis as well as for feedback of institutional data for individual process optimization as part of a quality management system.     

Technical and organisational feasibility of a multifunctional telemedicine system in an emergency medical service - an observational study

We evaluated the technical and organisational feasibility of a multifunctional telemedicine system in an emergency medical service (EMS) from the user's perspective. The telemedicine system was designed to transmit vital signs data and 12-lead-ECG data, send still pictures and allow voice communication and video transmission from an ambulance. The data were sent to a teleconsultation centre staffed with EMS physicians (tele-EMS physician). The system was used in 157 EMS missions. The applications were used successfully on 80% of missions for real-time vital signs transmission and on 97% for video transmission. The quality of the transmitted still images (n = 64) was: 23% excellent, 50% good, 17% moderate, 9% rather poor and 0% unusable. The quality of the video streaming (n = 36) was: 33% excellent, 56% good, 6% moderate, 6% rather poor and 0% unusable. The tele-EMS physician was able to assist the EMS team in several cases and provided the preliminary information for the hospital in nearly all missions. Use of the telemedical system in EMS is feasible and the quality of the transmitted images and video was satisfactory. However, technical reliability and availability need to be improved prior to routine use.