Liebherr (Austria)

Introduction: The infratip strut graft (ISG) is a trapezoid-shaped graft for the infratip area. The graft is used in combination with tongue-in-groove (TIG). The combination ISG-TIG is indicated in patients with weak lower lateral cartilages or a heavy soft tissue envelope. The hybrid technique shortens the nose with the control of the TIG and provides stability and refinement in the nasal tip. Methods: The ISG can be placed through an endonasal or external approach rhinoplasty. After one or two TIG sutures the ISG can be placed in the groove of the infratip lobule reaching as far as the tip defining points. A temporary needle stabilized the graft between the medial crura. The graft was fixated in between the medial crura of the infratip lobule with 2-3 absorbable mattress sutures. Results: We used the TIG-ISG hybrid technique in >50 patients. In conjunction to TIG the ISG is helpful to increase the stability of the infratip lobule and tip defining points to refine the nasal tip. Conclusions: The TIG-ISG technique is a proven technique to support and stabilize the medial crura in patients with weak lower lateral cartilages, a thick skin soft tissue envelope or a low caudal septal border in both primary and revision cases.

BackgroundHigh quality cardiopulmonary resuscitation is a key factor in survival with good overall quality of life after out-of-hospital cardiac arrest. Current evidence is predominantly based on studies conducted at low altitude, and do not take into account the special circumstances of alpine rescue missions. We therefore aimed to investigate the influence of physical strain at high altitude on the quality of cardiopulmonary resuscitation.MethodsAlpine field study. Twenty experienced mountaineers of the Austrian Mountain Rescue Service trained in Basic Life Support (BLS) performed BLS on a manikin in groups of two for 16 min. The scenario was executed at baseline altitude and immediately after a quick ascent over an altitude difference of 1200 m at 3454 m above sea level. The sequence of scenarios was randomised for a cross over analysis.Quality of CPR and exhaustion of participants (vital signs, Borg-Scale, Nine hole peg test) were measured and compared between high altitude and baseline using random-effects linear regression models.ResultsThe primary outcome of chest compression depth significantly decreased at high altitude compared to baseline by 1 cm (95% CI 0.5 to 1.3 cm, p < 0.01). There was a significant reduction in the proportion of chest compressions in the target depth (at least 5 cm pressure depth) by 55% (95% CI 29 to 82%, p < 0.01) and in the duration of the release phase by 75 ms (95% CI 48 to 101 ms, p < 0.01). No significant difference was found regarding hands-off times, compression frequency or exhaustion.ConclusionPhysical strain during a realistic alpine rescue mission scenario at high altitude led to a significant reduction in quality of resuscitation. Resuscitation guidelines developed at sea level are not directly applicable in the mountain terrain.

Simulation-based optimization problems are often an inherent part in engineering design tasks. This paper introduces one such use case, the design of a box-type boom of a crane, which requires a time consuming structural analysis for validation. To overcome high runtimes for optimization approaches with numerous calls to the structural analysis tool, we here present several ways of approximating the structural analysis results using surrogate models. Results show a strong correlation between certain statics input and output parameters, and that various surrogate modeling approaches yield similar results in terms of accuracy and impact of the predictors on the output. The box-type boom use case together with the surrogate models shall serve as an industrial optimization benchmark for comparing various algorithms on this simulation-based optimization problem.

The aim of our study was to assess whether cerebral artery clots undergo time-dependent morphological and compositional changes in acute ischemic stroke. We performed a retrospective chart review of patients admitted within 5 h from symptom onset to three European stroke centers and evaluated non-contrast-enhanced CT (NECT) for hyperdense artery signs (HAS) in 2565 scans. The occlusion site, density of HAS expressed in Hounsfield units (HU), area of HAS, and relative density (rHU) (HU clot/HU non-affected artery) were studied and related to time from symptom onset, clinical severity, stroke etiology, and laboratory parameters. A HAS was present in the middle cerebral artery (MCA) in 185 (7.2%) and further explored. The mean time from symptom onset to CT was 100 min (range 17–300). We found a time-dependent loss of density in the occluded M1 segment within the first 5 h (N = 118, 95% CI [−15, −2], p = 0.01). Further, the thrombus area in the M2 segment decreased with time (cubic trend N = 67, 95% CI [−63, −8], p = 0.02). Overall, and especially in the M2 segment, a lower clot area was associated with higher fibrinogen (−21.7%, 95% CI [−34.8, −5.8], p = 0.009). In conclusion, our results disclosed time-dependent changes of intracranial thrombi with regard to occlusion site, density and area.

During subsea lifting operations in harsh sea conditions, the involved crane system is subjected to extensive dynamic forces due to vertical vessel motion. Thus, active heave compensation systems can be used to compensate for vertical vessel motion and to reduce forces acting on the crane structure. Furthermore, such systems allow an exact positioning of the load on the seabed. However, active heave compensation systems always require knowledge about the vertical position of the crane depending on the ship's heave, roll, and pitch motion. Hence, an attitude estimation method for ships during subsea lifting operations is proposed. To estimate the roll and pitch motion of a vessel with high accuracy, rotation rate sensors are fused with accelerometers using an Extended Kalman Filter. Since an exact knowledge of the yaw motion is not required to determine the crane's vertical motion, the yaw angle is stabilized around zero with an additional virtual sensor signal. The attitude estimation algorithm is evaluated with simulation and measurement results from an experimental setup.

We retrospectively studied incidence, patterns, and severity of injury and hypothermia in 95 victims of crevasse accidents. Fifteen (16%) victims were already dead when the rescue team arrived on the scene. Asphyxia (8 victims) was typically caused by snow burial owing to a collapse of snow bridges covering crevasses and was observed only during winter sports activities on glaciers. In 7 patients, death was caused by lethal trauma. Severe or critical multisystem trauma (ISS ≥ 16) was found in an additional 16 victims (17%). Severe or critical injuries were predominantly thoracic injuries and injuries of the extremities and/or pelvic region. Severe accidental hypothermia was observed in 9 of the 95 victims (10%). Three of these suffered from hypothermic sudden cardiac arrest during rescue and were immediately evacuated with ongoing CPR; all 3 made a full recovery after extracorporeal rewarming. More than two-thirds of all victims were still trapped in the crevasse when the rescue team arrived. However, the majority of them could be relatively easily extricated using standard mountaineering equipment and improvised rescue techniques. Prolonged and difficult extrication efforts were needed in less than 10% of victims. Summing up, trauma and asphyxia are the most important causes of mortality and acute life-threatening medical problems in this study, but asphyxia will be far less common in mountain regions offering fewer glacier sport activities in the winter months. Hypothermic sudden cardiac arrest could not be prevented during the difficult conditions of crevasse extrication in one-third of all hypothermic victims; however, prognosis was excellent with advanced life support at the scene and immediate helicopter evacuation to extracorporeal rewarming.

For a totally enclosed fan-cooled induction machine, two methods of numerical analysis are compared with measurements. The first numerical method is based on computational fluid dynamics (CFDs) and the second one uses a thermal equivalent circuit (TEC). For the analysis based on CFD, a 3-D induction machine including housing is modeled. The numeric solution of the flow equations is determined for stationary temperature distributions. For the TEC, a discretized one-and-a-half-dimensional model of the induction machine is considered. With the TEC model, stationary and transient operating conditions can be simulated. Measurement results are determined by iron-copper-nickel sensors embedded in the stator winding and the housing, as well as by an IR sensor for measuring the rotor temperature. With these measurement signals, stationary and transient operating conditions can be analyzed. For stationary operating conditions, additionally, the housing temperatures are determined by an IR camera. The investigated simulation and measurement methods reveal different local and global temperatures, and thus, only certain aspects and characteristics of the obtained temperatures can be compared. Nevertheless, certain conclusions can be drawn from comparing these aspects considering the actual restrictions of each of the applied methods.