Helicopter Group Research Articles

Association of Pre-Hospital Helicopter Transport with Reduced Mortality in Traumatic Brain Injury in Japan: A Nationwide Retrospective Cohort Study.

Patients with traumatic brain injury (TBI) are severely injured patients who require timely, efficient, and specialized care. The effectiveness of helicopter emergency medical services (HEMS) for patients with TBI remains unclear. This study aimed to compare the mortality of patients with TBI transported by HEMS and ground ambulance using propensity score-matching analysis, and to analyze the effects of HEMS in various subpopulations. We conducted a retrospective analysis of the Japan Trauma Data Bank. The study period was from January 2004 to December 2018. The participants were divided into two groups: the helicopter group (patients transported by HEMS) and ground group (patients transported by ground ambulance). The principal outcome was death at hospital discharge. In total, 58,532 patients were eligible for analysis (ground group, n = 54,820 [93.7%]; helicopter group, n = 3712 [6.3%]). Helicopter transport decreased patient mortality at hospital discharge (adjusted odds ratio [OR], 0.83; 95% confidence interval [CI], 0.74–0.92). In propensity score-matched patients, the proportion of deaths at hospital discharge was lower in the helicopter (18.76%) than in the ground (21.21%) group (crude OR, 0.86; 95% CI, 0.77–0.96). The mortality rate in the helicopter group was significantly reduced in many subpopulations, especially in cases of severe TBI with a decreased level of consciousness or higher Injury Severity Score (ISS; Japan Coma Scale score 2 [adjusted OR, 0.60; 95% CI, 0.45–0.80] and ISS ≥50 [adjusted OR, 0.69; 95% CI, 0.48–0.99]). Although the study design was non-randomized, our findings in patients with TBI showed that HEMS conferred a mortality benefit over ground ambulance.

NSOF AND ROTARY-WING PLATFORMS – INTEGRATED OR JOINT?

Abstract: There is today a burgeoning discussion about how Romanian Naval Special Operations Forces (RNSOF) is supported in maritime operations by the conventional means of the Romanian Navy rotary-wing platforms. As part of this approach, we set out to analyze the regulatory framework for ensuring the support of naval aviation in the execution of NSOF missions. Thus, we will study the evolution of the cooperation of the ROU Navy Helicopter Group and NSOF from the perspective of regulations on cooperation, training, common standard operating procedures, references on standardization and safety in the execution of training and missions in the maritime environment. This research addresses an aspect of special operations that has yet to be explained adequately. To achieve this goal, we will describe how these operations are conducted in NATO countries, which have integrated maritime aviation in support of naval forces for special operations in the maritime environment. According to the specified causes to achieve our objectives, we will search for solutions to compensate or reduce the gap between necessity and reality. Through comparative analysis and documentation on the strategies used by foreign military forces, with similar roles and missions, we will provide solutions that will cover an area that can vary from adapting procedures to establishing the need to develop certain regulations. Our study is addressed to persons involved or interested in the military field and special naval operations and aims to highlight the importance of developing the NSOF capacity to cooperate with integrated maritime aviation and adjusted to the requirements of the execution of special maritime operations. Taking these recommendations into account will increase the effectiveness of NSOF maritime operations with the support of rotary-wing platforms while ensuring the transition to a robust/ real joint NSOF capability in response to existing threats in the Black Sea.

The utility of physician-staffed helicopters for managing individuals who experience severe isolated head trauma.

Objective: The authors retrospectively investigated prognostic factors for severe isolated head trauma in patients evacuated by a physician-staffed helicopter emergency medical service (HEMS) or ground ambulance using data from the Japan Trauma Data Bank (JTDB).Patients and Methods: This study was a retrospective analysis of data housed in the JTDB database. The study period was from January 2004 to May 2019. Subjects were divided into two groups according to the method of transportation: helicopter (i.e., HEMS), which included patients transported by a physician-staffed helicopter; and ambulance, which included patients transported by ground ambulance.Results: A total of 41,358 patients were enrolled in the study, including 2,029 in the helicopter group and 39,329 in the ambulance group. The ratio of males, median head Abbreviated Injury Scale and Injury Severity Scale (ISS) scores were significantly greater in the helicopter group than in the ambulance group, while the average age, median Glasgow Coma Scale, average Revised Trauma Score (RTS), and survival rate were significantly lower in the helicopter group than in the ambulance group. Of the variables that demonstrated statistical significance in the univariate analysis and classification of transportation and included in the multivariate analysis, the following were identified as significant predictors of survival outcomes: younger age, lower ISS, female sex, and greater RTS. HEMS was not a significant predictor of survival.Conclusion: The present study revealed no effect of HEMS transport on the outcomes of patients who experienced severe isolated head trauma compared with ground ambulance transportation. Further prospective studies, including an analysis of the operation time or distance traveled by the HEMS and the functional outcome(s) of patients with severe head injury transported by HEMS, are warranted.

Assessment of fatigue among aviation personnel involved in military flying in India employing Multidimensional Fatigue Symptom Inventory – Short Form (MFSI-SF)

Introduction: Fatigue has been recognized as a major safety hazard in modern aviation. There are numerous studies which have addressed various aspects such as the subjective symptoms, objective measures to diagnose fatigue, and its link with operator’s performance. This study was a novice attempt to assess the chronic fatigue among the aviation personnel employing “Multidimensional Fatigue Symptom Inventory – Short Form (MFSI-SF),” which is a well validated fatigue questionnaire. Material and Methods: A total of 93 aircrew and 30 ground crew of either sex from three military air bases were randomly selected for this cross-sectional observational study. The selected participants were requested to respond to 30 items listed in the survey form based on various types of symptoms along with severity that they experienced in the preceding 1 week. Results: The total fatigue score in case of the studied ground crew was higher than the studied aircrew group and this was statistically significant (P = 0.00001). The fighter, transport, and helicopter groups were not different from each other as far as their total fatigue score is concerned. However, ground crew group had significantly higher score in comparison to the score of the fighter, transport, and helicopter groups. In this study, 43.33% of ground crew participants and 11.82% of aircrew participants were observed to have fatigue. On stream-wise analysis, 2.94% of transport aircrew, 14.28% of fighter aircrew, 20.83% of helicopter aircrew, 52.17% Air Traffic Control (ATC) ground crew, and 14.28% of other ground crew who had participated in this study were fatigued. Conclusion: Fatigue in either form, i.e., acute or chronic, could affect both aircrew and ground crew. The present study had revealed that the proportion of ground crew suffering from chronic fatigue was more than the aircrew. The aircrew who were found to have such type of fatigue were younger in age and experience in comparison to their counterpart ground crew. Among the ground crew, a large percentage of ATC crew had this form of fatigue.

Clinical Investigation of Burn Patients Transported by Helicopter Based on the Japan Trauma Data Bank

ObjectiveWe retrospectively investigated the actual conditions of burn patients evacuated by helicopter in comparison to those evacuated by ground ambulance using the Japan Trauma Data Bank. MethodsThis study was a retrospective analysis of the data recorded in the Japan Trauma Data Bank between January 2004 and May 2019. After propensity score matching for the method of transportation, the survival rate was compared between the 2 groups. ResultsDuring the investigation period, there were 4,627 burn patients (helicopter group, n = 276; ambulance group, n = 4,351). After propensity score matching, there were no significant differences between the 2 groups in any of the assessed variables, and the survival rate did not differ to a statistically significant extent. ConclusionAfter propensity score matching, the survival rate of the helicopter group did not appear to be superior to the ambulance group. Further prospective studies are needed to explore the proper indications for air transportation of burn patients, which could potentially improve outcomes.

Association of helicopter transportation and improved mortality for patients with major trauma in the northern French Alps trauma system: an observational study based on the TRENAU registry

BackgroundPrompt prehospital triage and transportation are essential in an organised trauma system. The benefits of helicopter transportation on mortality in a physician-staffed pre-hospital trauma system remains unknown. The aim of the study was to assess the impact of helicopter transportation on mortality and prehospital triage.MethodsData collection was based on trauma registry for all consecutive major trauma patients transported by helicopter or ground ambulance in the Northern French Alps Trauma system between 2009 and 2017. The primary endpoint was in-hospital death. We performed multivariate logistic regression to compare death between helicopter and ground ambulance.ResultsOverall, 9458 major trauma patients were included. 37% (n = 3524) were transported by helicopter, and 56% (n = 5253) by ground ambulance. Prehospital time from the first call to the arrival at hospital was longer in the helicopter group compared to the ground ambulance group, respectively median time 95 [72–124] minutes and 85 [63–113] minutes (P < 0.001). Median transport time was similar between groups, 20 min [13–30] for helicopter and 21 min [14–32] for ground ambulance. Using multivariate logistic regression, helicopter was associated with reduced mortality compared to ground ambulance (adjusted OR 0.70; 95% CI, 0.53–0.92; P = 0.01) and with reduced undertriage (OR 0.69 95% CI, 0.60–0.80; P < 0.001).ConclusionHelicopter was associated with reduced in-hospital death and undertriage by one third. It did not decrease prehospital and transport times in a system with the same crew using both helicopter or ground ambulance. The mortality and undertriage benefits observed suggest that the helicopter is the proper mode for long-distant transport to a regional trauma centre.

Outcomes of interfacility helicopter transportation in acute stroke care.

To evaluate the long-term functional outcome of interhospital transfer of patients with stroke with suspected large vessel occlusion (LVO) using Helicopter Emergency Medical Services (HEMS). Records of consecutive patients evaluated through 2 telestroke networks and transferred to thrombectomy-capable stroke centers between March 2017 and March 2018 were reviewed. Inverse probability of treatment weighting (IPTW) using the propensity score was performed to address confounding factors. Multivariate logistic regression analysis with IPTW was used to determine whether HEMS were associated with good long-term functional outcome (modified Rankin scale score ≤ 2). A total of 199 patients were included; median age was 67 years (interquartile range [IQR] 55-79 years), 90 (45.2%) were female, 120 (60.3%) were white, and 100 (50.3%) were transferred by HEMS. No significant differences between the 2 groups were found in mean age, sex, race, IV tissue plasminogen activator (tPA) receipt, and thrombectomy receipt. The median baseline NIH Stroke Scale score was 14 (IQR 9-18) in the helicopter group vs 11 (IQR 6-18) for patients transferred by ground (p = 0.039). The median transportation time was 60 minutes (IQR 49-70 minutes) by HEMS and 84 minutes (IQR 25-102 minutes) by ground (p < 0.001). After weighting baseline characteristics, the use of HEMS was associated with higher odds of good long-term outcome (OR 4.738, 95% CI 2.15-10.444, p < 0.001) controlling for transportation time, door-in-door-out time, and thrombectomy and tPA receipt. The magnitude of the HEMS effect was larger in thrombectomy patients who had successful recanalization (OR 1.758, 95% CI 1.178-2.512, p = 0.027). HEMS use was associated with better long-term functional outcome in patients with suspected LVO, independently of transportation time.

Analysis of emergency air medical services over 9 years in the Penghu archipelago of Taiwan.

Objective:Emergency air medical services (EAMS) share a common helicopter system for prehospital care and transfer in several countries. In Penghu, two systems are involved in EAMS: the helicopter and C130 systems. Given their features and limitations, patients using the two systems have significantly different characteristics.Materials and Methods:To clearly understand the disease patterns and dynamic changes in transferred patients, we studied 1228 patients transported from Penghu to Taiwan between January 2009 and December 2017.Results:Our findings show that the helicopter group had more acute diseases, while the C130 system group had more chronic diseases. Cardiovascular disease was the most common diagnosis (328 patients, 26.71%), followed by cerebrovascular disease (263 patients, 21.41%) and gastrointestinal disease (221 patients, 17.99%). Following interventions to support local medicine by Tri-Service General Hospital and the establishment of a cardiac catheterization laboratory, the annual number of transported patients decreased, especially those with cardiovascular diseases. The disease pattern also shifted from acute to chronic disease.Conclusion:Current data indicate that the local medical system is developing the ability to manage chronic diseases and care problems. This article analyzes dynamic changes in the disease patterns of transferred patients in both EAMS groups, providing a strong foundation for developing local medical systems.

Out-of-hospital Times Using Helicopters Versus Ground Services for Emergency Patients

ObjectiveMinimizing out-of-hospital time reduces morbidity and mortality in patients with severe trauma, acute coronary syndrome, or acute stroke. Our objective was to compare out-of-hospital times by helicopter versus ground services when the estimated time of arrival on the scene was over 20 minutes. MethodsWe proposed a retrospective observational monocentric study following 2 cohorts. The helicopter group and the ground group included patients with severe trauma, acute coronary syndrome, or acute stroke transported by helicopter or ground services. ResultsTwo hundred thirty-nine patients were included; 118 were in the ground group, and 121 were in the helicopter group. Distances for the helicopter group were higher (62.1 ± 22.5 km vs. 27.6 ± 10.4 km, P < .001). When distances were over 35 km, the helicopter group was faster. We identified distance, need for surgery, and intensive care hospitalization as 3 predicting factors for choosing helicopters over ground modes of transport. ConclusionIn cases of severe trauma, acute coronary syndrome, or acute stroke, emergency medical helicopter transport can be chosen over ground transport when patients are in a severe state and when the distance is further than 35 km from the hospital.

Air Combating System-of-systems Effectiveness Analysis based on Modeling in Macro and Micro Perspective and Simulation

Large-scale helicopter group is an important part of the Air Combating System of Systems (ACSoS).How to plan the scale of helicopter group and achieve the best operational effectiveness is a focus of the ACSoS capability requirement analysis. Based on the macro-micro characteristic of the system of systems and the individual system, Air Combating combat models are divided into three types separately in macro and micro perspective. A UML/MM modeling method for Air Combating combat is proposed and the models are built in UML and mathematic method (MM) respectively. In addition, an Air Combating combat simulation system is developed and thirteen simulation plans of different scale values are designed as the inputs of the system .The optimal scale value of helicopter group under the certain scenario is gained through the analysis of the effectiveness based on the simulation results. In this scale condition, the ACSoS achieves its optimal survival and time effectiveness.

Effect of helicopter transport on neurological outcomes in a mouse model of embolic stroke with reperfusion: AIR-MICE pilot study.

Patients often suffer a stroke at a significant distance from a center capable of delivering endovascular therapy, thus requiring rapid transport by helicopter emergency medical services while receiving a recombinant tissue plasminogen activator infusion that was initiated locally. But little is known about how a helicopter flight may impact the safety and efficacy of recombinant tissue plasminogen activator-induced reperfusion and patient outcomes. To establish a new animal method to address with fidelity the safety and overall effect of helicopter emergency medical services during thrombolysis. Prospective randomized open blinded end-point study of an actual helicopter flight exposure. Adult C57BL/6 male mice were treated with a 10 mg/kg recombinant tissue plasminogen activator infusion two-hours after an embolic middle cerebral artery occlusion. Mice were randomized in pairs to simultaneously receive the infusion during a local helicopter flight or in a ground hangar. Eighteen mice (nine pairs) were analyzed. The paired t-test analysis showed nonsignificant smaller infarction volumes in the helicopter-assigned animals (mean pair difference 33 mm(3) , P = 0·33). The amount of hemorrhagic transformation between the helicopter and ground groups was 4·08 vs. 4·56 μl, respectively (paired t-test, P = 0·45). This study shows that helicopter emergency medical services do not have an inherent adverse effect on outcome in a mouse model of ischemic stroke with reperfusion. These results endorse the safety of the practice of using helicopter emergency medical services in stroke patients. The observed potential synergistic effect of helicopter-induced factors, such as vibration and changes in altitude, with reperfusion merits further exploration in animal experimental models and in stroke patients.

Abstract T P235: Assessing the Impact of Rotorcrafts in a Model of Induced Cerebral Embolism (AIR-MICE)

Objective: Stroke is a time-dependent emergency that often requires emergent helicopter evacuation, a critical early setting for which little is known about the positive or deleterious effect of altitude change, noise, acceleration and vibration. While many of these factors could worsen ischemic injury, the low frequency vibrations might augment clot lysis and enhance rtPA treatment. The objective of this study is to measure the feasibility, safety and potential effect of helicopter transport during thrombolysis in an animal model. Methodology: Prospective, randomized, open intervention and blinded end-point pilot study that combines a controlled experimental model with a real life helicopter flight exposure. Subjects were adult C57BL/6 male mice that simultaneously underwent an embolic middle cerebral artery occlusion (eMCAO) in pairs. Each pair of mice were randomized to receive 10 mg/kg of rtPA at two hours after eMCAO either during a one hour local flight in a MI2 turbine helicopter, or to simultaneously receive the same rtPA infusion while waiting in an airport hangar. Mice were sacrificed at 24 h. Primary outcome measure was infarct volume. Secondary outcome was neurological scores. Results: Eighteen mice (9 pairs) were analyzed. Lower infarction volumes were seen in the helicopter assigned group in 6/9 pairs. The mean infarction volumes were 246.6 mm 3 (SD 154) for ground group and 213.6 mm 3 (SD 170) for the helicopter group. A paired t-test analysis showed lesser infarction volumes in the helicopter group (mean difference 33 mm 3 , p=0.33), a difference that was not influenced when adjusting for ambient temperature and atmospheric pressure. The neurological scores were similar in the ground and helicopter groups (1.28 vs. 1.22, p=0.88). Conclusion: Randomized trials of the effect of helicopter transport in a mouse model of eMCAO are feasible, and desirable to test the effect of neuroprotective therapies in this unique setting. These results endorse the safety of aerial transport, which might be associated with lower infarction volumes. The potential synergist effect of vibration in the rotorcraft with reperfusion needs to be explored further.

Time–Frequency Distribution Analyses of Ku-Band Radar Doppler Echo Signals

AbstractReal radar echo signals of a pedestrian, vehicle and group of helicopters are analyzed in order to maximize signal energy around central Doppler frequency in time–frequency plane. An optimization, preserving this concentration, is suggested based on three well-known concentration measures. Various window functions and time–frequency distributions were optimization inputs. Conducted experiments on an analytic and three real signals have shown that energy concentration significantly depends on used time–frequency distribution and window function, for all three used criteria.

Cooperative and Consensus-Based Approaches to Formation Control of Autonomous Vehicles

This paper presents a distributed robust control scheme for the formation flight of autonomous aerial vehicles, which is obtained from combining two existing approaches: cooperative and consensus-based formation control. These schemes are examined using a mixed ℋ∞/ℓ1 design approach to provide robustness against arbitrary changes of the communication topology as well as any communication delays. The presented architectures mainly differ in the coupling of the agents, which influences performance and formation maintenance. Furthermore, these approaches are analyzed by means of a simulation study on a group of quad-rotor helicopters. The results indicate significant benefits from combining these existing schemes.

Is air transport of stroke patients faster than ground transport? A prospective controlled observational study

BackgroundHelicopters are widely used for interhospital transfers of stroke patients, but the benefit is sparsely documented. We hypothesised that helicopter transport would reduce system delay to thrombolytic treatment at the...

CT Examination of the Pericardium and Lungs in Helicopter Pilots Exposed to Vibration and Noise

Helicopter pilots are exposed to whole body vibration and noise in their working environment. Some researchers have found that kinetic energy from both noise and vibration is believed to affect pericardial thickness and lead to pulmonary fibrosis, known as vibroacoustic disease. The aim of this project was to determine whether we could discover similar findings in a selection of helicopter pilots. A case control study where 27 helicopter pilots were compared to an age-matched control group of typical office workers was conducted. High resolution CT scanning of the thorax was used as the diagnostic method. Two medical radiologists interpreted the images independently, blinded to whether the subjects were pilots or from the control group. There were no signs of pericardial thickening or significant lung fibrosis formations in either of the groups. The average pericardium thickness for the helicopter group was 1.38 mm, SD = 0.54 mm, and for the control group: 1.37 mm, SD = 0.33 mm. There was no significant correlation between pericardium thickness and flight hours or age. The average pericardial thickness values for the helicopter and the age-matched control groups were almost identical. The results are within normal limits and comparable to an American study where 21 normal individuals were measured to 1.2 mm +/- 0.8 mm in an average of 26 different points by using trans-esophageal echocardiography. On the basis of the CT scans, our findings do not support the existence of vibroacoustic disease, where pericardial thickening is the most prominent sign.

RE: Helicopter Evacuation of Trauma Victims in Los Angeles: Does It Improve Survival?

To the Editor I read with interest this review [1] of the experience from this well-reputed center for the care of trauma. The role of helicopters for the treatment of trauma is indeed controversial in the urban setting and thus this study is relevant. Their study showed that helicopter use did not reduce comparative statistical survival. What I found interesting is the apparent contrast between what is known as statistical versus clinical significance in this paper. Although the mortality rates were not statistically different across the groups after multivariate analysis, there seems to be a bias, in that the group transported by helicopter was more severely injured as reflected by parameters and the need for interventions in both the preand in-hospital phases of care, except for thoracotomy. The fact that the mortality is not statistically different is not qualified with a comparison to predicted mortality, which may actually reveal the clinically significant difference. One would suspect that the predicted survival for a less severely injured group would be better than for a more severely injured cohort, thus making this a relevant comparison to examine. If the helicopter group is shown to have a less than predicted mortality, especially if the predicted mortality of the comparison group is as predicted, then it would follow that helicopter transport may improve clinical survival. The in-hospital management, however, remains a confounder that is difficult to quantify. I would like to challenge the authors to undertake such an analysis and provide this as an addendum to prove or refute their assertions.

Endotracheal tube cuff pressures in patients intubated before transport

Introduction Prolonged endotracheal tube cuff pressures (ETTCPs) greater than 30 cm H 2O cause complications ranging from sore throat to rare cases of tracheoesophageal fistula. In a series of patients, we sought to determine the proportion of patients with overinflated cuffs and to determine whether overinflation was associated with demographics, diagnostic category, or intubator credentials. Methods Between July 2007 and April 2008, we measured cuff pressures on a convenience sample of patients drawn from 2 groups. The “helicopter group” had pressure measured before transport by a single aeromedical transport service. The “hospital group” had pressure measured upon arrival to 1 of 2 emergency departments after being intubated before transport. Results Three hundred patients aged 4 to 92 years (median, 57) were studied: 59.7% were male; and diagnostic categories were neurologic (33.7%), trauma (32.7%), cardiac (12.7%), and general medical/surgical (21.0%). Intubation occurred 1 to 28 000 minutes before ETTCP assessment (median, 60). Endotracheal tube cuff pressure was greater than 30 cm H 2O in 64.7% and ranged from 10 to 180 (median, 40). Forty-nine percent of patients had ETTCP greater than 40 cm H 2O. There was no association between ETTCP and age group, sex, diagnostic category, ETT size, time between intubation and ETTCP assessment, or intubator credentials. Conclusions The most compelling results of the study are the high rates of elevated ETTCPs. Furthermore, there were no clear risk factors for elevated ETTCP. Although the risk of elevated ETTCP in the prehospital to acute care time frame is unclear, it seems reasonable to measure ETTCP after intubation in all patients.

A MODEL PREDICTIVE FRAMEWORK FOR AUTONOMOUS 3D FORMATION FLIGHT OF HELICOPTER GROUPS

In this paper, a framework for control of general helicopter formations is presented. The framework is constructed using two main control schemes for navigation of a helicopter group in three-dimensional (3D) formations. These schemes utilize geometrical parameters of the formation layout to maintain the position of the group members with respect to each other. Any 3D formation grid of helicopters can be defined by using these blocks as construction units. Using the defined geometrical formation parameters, two decentralized controllers are designed based on the Nonlinear Model Predictive Control (NMPC) method. The feasibility of the real-time implementation of the developed controller is discussed. Also, dis- turbance rejection and robustness to parameter uncertainty of the controllers are shown by simulations.

Non-Iterative nonlinear model predictive approach applied to the control of helicopters’ group formation

Two geometrical formation schemes that allow the definition of any desired three-dimensional formation mesh for a group of helicopters are presented. Each formation scheme, which defines the leader–follower geometry of the formation mesh, has four parameters. These formation parameters are directly used as the output of decentralized controllers that independently control each helicopter in the group. The decentralized controllers are designed using a non-iterative Nonlinear Model Predictive Control (NMPC) method. The Continuation method is used for solving, in real-time, for future control actions that minimize a NMPC cost function. It is shown by analyzing the number of floating point operations per calculation cycle that the calculation load of the NMPC method for this application is quite manageable for today’s industrial embedded computers. Simulations show that the formation schemes along with the NMPC controller can initialize and keep the formation of a group of helicopters even in the presence of bounded parameter uncertainty and environmental disturbance.