OneMax is not the Easiest Function for Fitness Improvements.

We study the (1:s+1) success rule for controlling the population size of the (1,λ)- EA. It was shown by Hevia Fajardo and Sudholt that this parameter control mechanism can run into problems for large s if the fitness landscape is too easy. They conjectured that this problem is worst for the ONEMAX benchmark, since in some well-established sense ONEMAX is known to be the easiest fitness landscape. In this paper we disprove this conjecture. We show that there exist s and ɛ such that the self-adjusting (1,λ)-EA with the (1:s+1)-rule optimizes ONEMAX efficiently when started with ɛn zero-bits, but does not find the optimum in polynomial time on DYNAMIC BINVAL. Hence, we show that there are landscapes where the problem of the (1:s+1)-rule for controlling the population size of the (1,λ)-EA is more severe than for ONEMAX. The key insight is that, while ONEMAX is the easiest function for decreasing the distance to the optimum, it is not the easiest fitness landscape with respect to finding fitness-improving steps.

Clinical relevance of lung transplantation for COVID-19 ARDS: a nationwide study.

BACKGROUND: Although the number of lung transplantations (LTx) performed worldwide for COVID-19 induced acute respiratory distress syndrome (ARDS) is still low, there is general agreement that this treatment can save a subgroup of most severly ill patients with irreversible lung damage. However, the true proportion of patients eligible for LTx, the overall outcome and the impact of LTx to the pandemic are unknown. METHODS: A retrospective analysis was performed using a nationwide registry of hospitalised patients with confirmed severe acute respiratory syndrome coronavirus type 2 (SARS-Cov-2) infection admitted between January 1, 2020 and May 30, 2021 in Austria. Patients referred to one of the two Austrian LTx centers were analyzed and grouped into patients accepted and rejected for LTx. Detailed outcome analysis was performed for all patients who received a LTx for post-COVID-19 ARDS and compared to patients who underwent LTx for other indications. RESULTS: Between January 1, 2020 and May 30, 2021, 39.485 patients were hospitalised for COVID-19 in Austria. 2323 required mechanical ventilation, 183 received extra-corporeal membrane oxygenation (ECMO) support. 106 patients with severe COVID-19 ARDS were referred for LTx. Of these, 19 (18%) underwent LTx. 30-day mortality after LTx was 0% for COVID-19 ARDS transplant recipients. With a median follow-up of 134 (47-450) days, 14/19 patients are alive. CONCLUSIONS: Early referral of ECMO patients to a LTx center is pivotal in order to select patients eligible for LTx. Transplantation offers excellent midterm outcomes and should be incorporated in the treatment algorithm of post-COVID-19 ARDS.

Efficacy of prehospital administration of fibrinogen concentrate in trauma patients bleeding or presumed to bleed (FIinTIC): A multicentre, double-blind, placebo-controlled, randomised pilot study.

BACKGROUND: Trauma-induced coagulopathy (TIC) substantially contributes to mortality in bleeding trauma patients. OBJECTIVE: The aim of the study was to administer fibrinogen concentrate in the prehospital setting to improve blood clot stability in trauma patients bleeding or presumed to bleed. DESIGN: A prospective, randomised, placebo-controlled, double-blinded, international clinical trial. SETTING: This emergency care trial was conducted in 12 Helicopter Emergency Medical Services (HEMS) and Emergency Doctors' vehicles (NEF or NAW) and four trauma centres in Austria, Germany and Czech Republic between 2011 and 2015. PATIENTS: A total of 53 evaluable trauma patients aged at least 18 years with major bleeding and in need of volume therapy were included, of whom 28 received fibrinogen concentrate and 25 received placebo. INTERVENTIONS: Patients were allocated to receive either fibrinogen concentrate or placebo prehospital at the scene or during transportation to the study centre. MAIN OUTCOME MEASURES: Primary outcome was the assessment of clot stability as reflected by maximum clot firmness in the FIBTEM assay (FIBTEM MCF) before and after administration of the study drug. RESULTS: Median FIBTEM MCF decreased in the placebo group between baseline (before administration of study treatment) and admission to the Emergency Department, from a median of 12.5 [IQR 10.5 to 14] mm to 11 [9.5 to 13] mm (P = 0.0226), but increased in the FC Group from 13 [11 to 15] mm to 15 [13.5 to 17] mm (P = 0.0062). The median between-group difference in the change in FIBTEM MCF was 5 [3 to 7] mm (P < 0.0001). Median fibrinogen plasma concentrations in the fibrinogen concentrate Group were kept above the recommended critical threshold of 2.0 g l-1 throughout the observation period. CONCLUSION: Early fibrinogen concentrate administration is feasible in the complex and time-sensitive environment of prehospital trauma care. It protects against early fibrinogen depletion, and promotes rapid blood clot initiation and clot stability. TRIAL REGISTRY NUMBERS: EudraCT: 2010-022923-31 and ClinicalTrials.gov: NCT01475344.

A Randomized Controlled Trial Comparing Adductor Canal Catheter and Intraarticular Catheter After Primary Total Knee Arthroplasty.

BACKGROUND: Multimodal analgesia, including peripheral nerve blocks, is recommended for postoperative pain relief after total knee arthroplasty (TKA). To date, no randomized controlled trial has compared the efficacy of adductor canal catheters (ACCs) and intraarticular catheters (IACs) in patients undergoing TKA. METHODS: A prospective, randomized control trial was performed in 96 primary, unilateral TKA patients comparing ACC with IAC between April, 2014 and August, 2015. Primary outcome measured was numeric pain scores before and after the first physical therapy session on postoperative day 1. Secondary outcomes were oxycodone consumption at 24 and 48 hours, total opioid consumption in morphine equivalents at 24 and 48 hours, active and passive range of motion during physical therapy, patient satisfaction, and length of stay. RESULTS: Results demonstrated that the ACC provided significantly better pain control on postoperative day 1 (P = .02) compared with the IAC. ACC trended toward significantly reduced oxycodone consumption at 24 hours postoperatively compared to IAC (25.64 vs 34.67 mg, P = .057). However, total opioid consumption was equivalent between the groups at 24 hours (32.24 vs 38.55 P = .185) or 48 hours (45.2 vs 52.0, P = .330). CONCLUSION: ACC should be considered as part of a multimodal pain regimen after primary, unilateral TKA and provides a better option for pain control after discharge.

HEMS in Alpine Rescue for Pediatric Emergencies.

OBJECTIVE: The objective of this study was to describe the pediatric emergencies encountered by the Christophorus-1 helicopter emergency medical service (HEMS) during a period of 2 years. METHODS: Emergency treatment of pediatric casualties by HEMS was evaluated at a helicopter base. Children up to 14 years who were treated by HEMS emergency physicians from Christophorus-1 during primary missions in the alpine region were retrospectively enrolled. RESULTS: Of the 1314 HEMS operations conducted during a 2-year investigation period, pediatric emergencies accounted for 114 (8.7%). Trauma was the most common emergency indication (91.3%) in alpine areas, and 77.5% of the indications were related to skiing and snowboarding; 11.3% of the prehospital pediatric emergencies were classified as life-threatening. Interventions on site were rendered in 46.3% of cases. Mean and SD intervals for approach were 11.0 ± 3.0 minutes; for treatment, 14.0 ± 6.0 minutes; and for transport, 8.0 ± 4.0 minutes. Intervals on site were significantly longer whenever it was necessary to search for an interim landing place (P < .001) or perform rope extrication (P < .001). Aggravating environmental conditions such as low temperature (78.8%), rocky terrain (18.8%), or precipitation (12.5%) were common. CONCLUSIONS: Rapid procedures are preferred to sustained on-scene treatment, particularly when surrounding conditions are hostile. HEMS emergency physicians attempt to keep on-site intervals short and treatment and monitoring to the essential to minimize delay in rescue.

Prolonged critical avalanche burial for nearly 23 h with severe hypothermia and severe frostbite with good recovery: a case report.

BACKGROUND: Accidental hypothermia with severe frostbite is a rare combination of injuries with a high risk for long-term sequelae. There are widely accepted recommendations for the management of avalanche victims and for frostbite treatment, but no recommendation exists for the treatment of frostbite in severe hypothermic patients, specifically for the management of hypothermic avalanche victims presenting with frostbite. CASE PRESENTATION: We present a case of a previously healthy, 53-year-old male skier who was critically buried by an avalanche at 2300 m of altitude at an ambient temperature of - 8 °C for nearly 23 h. The victim was found with the right hand out of the snow and an air connection to outside. He was somnolent with Glasgow Coma Scale 11 (Eye 4, Verbal 2, Motor 5) and spontaneously breathing, in a severely hypothermic state with an initial core temperature of 23.1 °C and signs of cold injuries in all four extremities. After rescue and active external forced air rewarming in the intensive care unit, the clinical signs of first-degree frostbite on both feet and the left hand vanished, while third- to fourth-degree frostbite injuries became apparent on all fingers of the right hand. After reaching a core body temperature of approximately 36 °C, aggressive frostbite treatment was started with peripheral arterial catheter-directed thrombolysis with alteplase, intravenous iloprost, ibuprofen, dexamethasone and regional sympathicolysis with a right-sided continuous axillary block. After ten months, the patient had no tissue loss but needed neuropathic pain treatment with pregabalin. CONCLUSION: The combination of severe accidental hypothermia and severe frostbite is rare and challenging, as drug metabolism is unpredictable in a hypothermic patient and no recommendations for combined treatment exist. There is general agreement to give hypothermia treatment the priority and to begin frostbite treatment as early as possible after full rewarming of the patient. More evidence is needed to identify the optimal dosage and time point to initiate treatment of frostbite in severely hypothermic patients. This should be taken into consideration by future treatment recommendations.

Critically buried avalanche victims can develop severe hypothermia in less than 60 min.

BACKGROUND: A major challenge in the management of avalanche victims in cardiac arrest is differentiating hypothermic from non-hypothermic cardiac arrest, as management and prognosis differ. Duration of burial with a cutoff of 60 min is currently recommended by the resuscitation guidelines as a parameter to aid in this differentiation However, the fastest cooling rate under the snow reported so far is 9.4 °C per hour, suggesting that it would take 45 min to cool below 30 °C, which is the temperature threshold below which a hypothermic cardiac arrest can occur. CASE PRESENTATION: We describe a case with a cooling rate of 14 °C per hour, assessed on site with an oesophageal temperature probe. This is by far the most rapid cooling rate after critical avalanche burial reported in the literature and further challenges the recommended 60 min threshold for triage decisions. The patient was transported under continuous mechanical CPR to an ECLS facility and rewarmed with VA-ECMO, although his HOPE score was 3% only. After three days he developed brain death and became an organ donor. CONCLUSIONS: With this case we would like to underline three important aspects: first, whenever possible, core body temperature should be used instead of burial duration to make triage decisions. Second, the HOPE score, which is not well validated for avalanche victims, had a good discriminatory ability in our case. Third, although extracorporeal rewarming was futile for the patient, he donated his organs. Thus, even if the probability of survival of a hypothermic avalanche patient is low based on the HOPE score, ECLS should not be withheld by default and the possibility of organ donation should be considered.

Respiratory failure and spontaneous hypoglycemia during noninvasive rewarming from 24.7°C (76.5°F) core body temperature after prolonged avalanche burial.

Clinical reports on management and rewarming complications after prolonged avalanche burial are not common. We present a case of an unreported combination of respiratory failure and unexpected spontaneous hypoglycemia during noninvasive rewarming from severe hypothermia. We collected anecdotal observations in a 42-year-old, previously healthy, male backcountry skier admitted to the ICU at a tertiary care center after 2 hours 7 minutes of complete avalanche burial, who presented with a patent airway and a core body temperature of 25.0°C (77.0°F) on extrication. There was no decrease in core body temperature during transport (from 25.0°C [77.0°F] to 24.7°C [76.5°F]). Atrial fibrillation occurred during active noninvasive external rewarming (to 37.0°C [98.6°F] during 5 hours), followed by pulmonary edema and respiratory failure (SaO(2) 73% and PaO(2)/FIO(2) 161 mm Hg), which resolved with endotracheal intubation and continuous positive end-respiratory pressure. Moreover, a marked spontaneous glycemic imbalance (from 22.2 to 1.4 mmol/L) was observed. Despite a possible favorable outcome, clinicians should be prepared to identify and treat severe respiratory problems and spontaneous hypoglycemia during noninvasive rewarming of severely hypothermic avalanche victims.

COVID-19 Pandemic in Mountainous Areas: Impact, Mitigation Strategies, and New Technologies in Search and Rescue Operations.

van Veelen, Michiel J., Anna Voegele, Simon Rauch, Marc Kaufmann, Hermann Brugger, and Giacomo Strapazzon. COVID-19 pandemic in mountainous areas: impact, mitigation strategies, and new technologies in search and rescue operations. High Alt Med Biol. 22:335-341, 2021.-Mitigating the spread of COVID-19, an airborne infection, can lead to delays in the prehospital response and impair the performance of search and rescue (SAR) services in mountainous and remote areas. We provide an overview of the developing epidemiological situation related to the COVID-19 pandemic in mountainous areas and review current protocols to determine their suitability for mountain rescue teams. We also discuss using novel technologies to reduce the adverse effects caused by COVID-19 mitigation strategies such as delays caused by donning personal protective equipment (PPE) and reduced rescuer performance due to impaired movement and ventilation. COVID-19 has spread even in mountainous and remote locations. Dedicated protocols for the use of PPE appropriate for SAR rescuers exerting physical effort in remote areas and using technologies such as drones, telemedicine, and localization and contact tracing applications could contribute to an effective and timely emergency response in mountainous and remote settings.

Distal leg protection for peripheral cannulation in minimally invasive and totally endoscopic cardiac surgery.

BACKGROUND: The introduction of minimally invasive and totally endoscopic cardiac surgery is associated with increased use of femoral artery perfusion. Selective antegrade perfusion of the cannulated artery may be a helpful strategy to avoid ischemia of the lower extremities. The aim of the study was to evaluate the efficacy of selective distal vessel perfusion under continuous monitoring of oxygen saturation using near-infrared spectroscopy (NIRS). METHODS: All patients (n = 236) who underwent peripheral cannulation for remote access perfusion and endoaortic balloon occlusion for minimally invasive or totally endoscopic cardiac surgery were prospectively analyzed. Perioperative complications, creatine kinase levels, and major complications at the long-term follow-up were recorded. RESULTS: Minor or major complications of leg perfusion occurred in only 4 patients (1.7%); the complications in 2 of the patients were associated with an additional arterial cannula placed at the contralateral side. NIRS monitoring revealed diminished perfusion in 5 cases. Even patients with complications associated with remote-access perfusion had a rapid recovery, and no residual peripheral vascular complication was detected during follow-up. CONCLUSIONS: The use of antegrade selective perfusion of the lower extremity at the side of peripheral cannulation for port-access perfusion and endoaortic occlusion is of utmost importance in patients undergoing minimally invasive or endoscopic cardiac surgery. NIRS monitoring has proved to be very helpful for the diagnosis of impaired leg perfusion.

Changes in injury patterns and severity in a helicopter air-rescue system over a 6-year period.

OBJECTIVE: To study the influence of current trends in alpine sports on the frequency and types of injuries handled by a helicopter-based emergency medical system (HEMS) in a wilderness mountain region. METHODS: A retrospective review of medical reports at a single emergency helicopter port (Christophorus-1 air rescue) in Innsbruck, Austria, was conducted for comparison between two 3-year periods (1998-2000 and 2001-2003). RESULTS: Comparing the two 3-year periods, the proportion of leisure-time injuries leading to HEMS activation increased, whereas the frequency of life-threatening injuries significantly declined (P = .001). There was significant increase in injuries during mountain hiking and rock climbing (P = .002), during swimming (P = .013), and in avalanches (P = .019). Most injuries (70.1%) were recorded for skiers, and 68.3% involved tourists. During the investigation period, the high National Advisory Committee of Aeronautics scores showed a decreasing trend, whereas Glasgow Coma Scale scores and low National Advisory Committee of Aeronautics scores tended to increase (P = .048). CONCLUSIONS: For the HEMS in this study, there has been an increasing number of calls for help from persons involved in outdoor leisure activities. As the number of life-threatening injuries declines, HEMSs more frequently serve as means of rescue rather than as providers of emergency treatment.