Oxygen accumulation and associated dangers in rescue helicopters.

BACKGROUND: At the time of the COVID-19 pandemic, devastating incidents increased due to frequent oxygen administration to patients. The dangers associated with the use of oxygen, especially through local enrichments and formation of "oxygen clouds", have been well understood for years. Nevertheless, dramatic incidents continue to occur, since fire hazard increases exponentially with oxygen concentrations above 23%. Rescue helicopters are at a particular high risk, because of technical reasons such as oxygen use in a very small space, surrounded by kerosene lines, electronic relays and extremely hot surfaces. METHODS: In this study three different sized rescue helicopter models (Airbus H135, H145 and MD902) were examined. Oxygen enrichment in the cabin was measured with an oxymeter during a delivery rate of 15 l/min constant flow for 60 min. Furthermore, the clearance of the enriched atmosphere was tested in different situations and with different ventilation methods. To make the airflow visible, a fog machine was used to fill the helicopter cabin. RESULTS: Oxygen accumulation above 21% was detected in every helicopter. After 10-15 min, the critical 23% threshold was exceeded in all three aircrafts. The highest concentration was detected in the smallest machine (MD902) after 60 min with 27.4%. Moreover, oxygen clouds persisted in the rear and the bottom of the aircrafts, even when the front doors were opened. This was most pronounced in the largest aircraft, the H145 from Airbus Helicopters. Complete and rapid removal of elevated oxygen concentrations was achieved only by cross-ventilation within 1 min. CONCLUSIONS: Oxygen should be handled with particular care in rescue helicopters. Adapted checklists and precautions can help to prevent oxygen accumulation, and thus, fatal incidents. To our knowledge, this is the first study, which analyzed oxygen concentrations in different settings in rescue helicopters.

Oxygenation Performance of Different Non-Invasive Devices for Treatment of Decompression Illness and Carbon Monoxide Poisoning.

Study Objective: Application of high concentrations of oxygen to increase oxygen partial pressure (pO2) is the most important treatment for patients with carbon monoxide intoxication or divers with suspected decompression illness. The aim of this study was to evaluate the oxygenation performance of various non-invasive oxygen systems. Methods: The effect of different oxygen systems on arterial pO2, pCO2 and pH and their subjective comfort was evaluated in 30 healthy participants. Eight devices were included: nasal cannula, non-rebreather mask, AirLife Open mask, Flow-Safe II CPAP device, SuperNO2VA nasal PAP device, all operated with 15 L/min constant flow oxygen; nasal high-flow (50 L/min flow, 1.0 FiO2), non-invasive positive pressure ventilation (NPPV, 12 PEEP, 4 ASB, 1.0 FiO2) and a standard diving regulator (operated with pure oxygen). Results: Diving regulator, SuperNO2VA, nasal high-flow and NPPV achieved mean arterial pO2 concentrations between 538 and 556 mm Hg within 5 minutes. The AirLife Open mask, the nasal cannula and the non-rebreather mask achieved concentrations of 348-451 mm Hg and the Flow-Safe II device 270 mm Hg. Except for the AirLife open mask, pCO2 decreased and pH increased with all devices. The highest pH values were observed with NPPV, diving regulator, Flow-Safe II and nasal high-flow but apparent hyperventilation was uncommon. The AirLife Open and the non-rebreather mask were the most comfortable, the SuperNO2VA and the nasal cannula the most uncomfortable devices. Conclusion: A standard diving regulator and the SuperNO2VA device were equally effective in providing highest physiologically possible pO2 as compared to nasal high-flow and NPPV.

Systemic inflammation as fuel for acute liver injury in COVID-19.

BACKGROUND: A cytokine storm conceivably contributes to manifestations of corona virus disease (COVID-19). Inflammatory cytokines such as interleukin-6 (IL-6) cause acute liver injury while serum detectability indicates systemic inflammation. AIMS: We explored a link between systemic IL-6, related acute phase proteins and liver injury in hospitalized COVID-19 patients. METHODS: 655 patients with suspected COVID-19 were screened in the emergency department at the University Hospital of Innsbruck, Austria, between February and April 2020. 96 patients (∼15%) were hospitalized with COVID-19. 15 patients required intensive-care treatment (ICT). Plasma aminotransferases, alkaline phosphatase, bilirubin, and gamma glutamyl transferase, as well as IL-6, C-reactive protein (CRP), ferritin and lactate dehydrogenase (LDH) were determined by standard clinical assays. RESULTS: Of all hospitalized COVID-19 patients, 41 (42%) showed elevated aspartate aminotransferase (AST) concentration. COVID-19 patients with elevated AST exhibited significantly higher IL-6 (p < 0.001), ferritin (p < 0.001), LDH (p < 0.001) and CRP (p < 0.05) serum concentrations compared to patients with normal AST. Liver injury correlated with systemic IL-6 (p < 0.001), CRP (p < 0.001), ferritin (p < 0.001) and LDH (p < 0.001) concentration. In COVID-19 patients requiring ICT, correlations were more pronounced. CONCLUSION: Systemic inflammation could be a fuel for hepatic injury in COVID-19.

Cardiopulmonary recovery after COVID-19: an observational prospective multicentre trial.

BACKGROUND: After the 2002/2003 severe acute respiratory syndrome outbreak, 30% of survivors exhibited persisting structural pulmonary abnormalities. The long-term pulmonary sequelae of coronavirus disease 2019 (COVID-19) are yet unknown, and comprehensive clinical follow-up data are lacking. METHODS: In this prospective, multicentre, observational study, we systematically evaluated the cardiopulmonary damage in subjects recovering from COVID-19 at 60 and 100 days after confirmed diagnosis. We conducted a detailed questionnaire, clinical examination, laboratory testing, lung function analysis, echocardiography and thoracic low-dose computed tomography (CT). RESULTS: Data from 145 COVID-19 patients were evaluated, and 41% of all subjects exhibited persistent symptoms 100 days after COVID-19 onset, with dyspnoea being most frequent (36%). Accordingly, patients still displayed an impaired lung function, with a reduced diffusing capacity in 21% of the cohort being the most prominent finding. Cardiac impairment, including a reduced left ventricular function or signs of pulmonary hypertension, was only present in a minority of subjects. CT scans unveiled persisting lung pathologies in 63% of patients, mainly consisting of bilateral ground-glass opacities and/or reticulation in the lower lung lobes, without radiological signs of pulmonary fibrosis. Sequential follow-up evaluations at 60 and 100 days after COVID-19 onset demonstrated a vast improvement of symptoms and CT abnormalities over time. CONCLUSION: A relevant percentage of post-COVID-19 patients presented with persisting symptoms and lung function impairment along with radiological pulmonary abnormalities >100 days after the diagnosis of COVID-19. However, our results indicate a significant improvement in symptoms and cardiopulmonary status over time.

Livedo Racemosa - The Pathophysiology of Decompression-Associated Cutis Marmorata and Right/Left Shunt.

Decompression sickness and arterial gas embolism, collectively known as decompression illness (DCI), are serious medical conditions that can result from compressed gas diving. DCI can present with a wide range of physiologic and neurologic symptoms. In diving medicine, skin manifestations are usually described in general as cutis marmorata (CM). Mainly in the Anglo-American literature the terms cutis marmorata, livedo reticularis (LR), and livedo racemosa (LRC) are used interchangeably but actually describe pathophysiologically different phenomena. CM is a synonym for LR, which is a physiological and benign, livid circular discoloration with a net-like, symmetric, reversible, and uniform pattern. The decompression-associated skin discolorations, however, correspond to the pathological, irregular, broken netlike pattern of LRC. Unlike in diving medicine, in clinical medicine/dermatology the pathology of livedo racemosa is well described as a thrombotic/embolic occlusion of arteries. This concept of arterial occlusion suggests that the decompression-associated livedo racemosa may be also caused by arterial gas embolism. Recent studies have shown a high correlation of cardiac right/left (R/L) shunts with arterial gas embolism and skin bends in divers with unexplained DCI. To further investigate this hypothesis, a retrospective analysis was undertaken in a population of Austrian, Swiss, and German divers. The R/L shunt screening results of 18 divers who suffered from an unexplained decompression illness (DCI) and presented with livedo racemosa were retrospectively analyzed. All of the divers were diagnosed with a R/L shunt, 83% with a cardiac shunt [patent foramen ovale (PFO)/atrium septum defect (ASD)], and 17% with a non-cardiac shunt. We therefore not only confirm this hypothesis but when using appropriate echocardiographic techniques even found a 100% match between skin lesions and R/L shunt. In conclusion, in diving medicine the term cutis marmorata/livedo reticularis is used incorrectly for describing the actual pathology of livedo racemosa. Moreover, this pathology could be a good explanation for the high correlation of livedo racemosa with cardiac and non-cardiac right/left shunts in divers without omission of decompression procedures.

Liver stiffness by transient elastography accompanies illness severity in COVID-19.

OBJECTIVE: Severe liver damage is associated with worse outcome in COVID-19. Our aim was to explore the degree of liver damage, liver stiffness (LS) and severity of illness in patients with COVID-19. DESIGN: We investigated 32 patients with COVID-19 admitted to the University Hospital of Innsbruck in a prospective cross-sectional study. We performed laboratory testing, liver and spleen sonography and elastography to measure organ stiffness. RESULTS: 12 patients (38%) showed elevated aminotransferases and gamma-glutamyltransferase levels. LS was positively correlated with elevated aminotransferase levels in patients with COVID-19 compared with those without elevated enzymes. Even mild liver damage raised LS significantly in COVID-19 as it was in patients with gastrointestinal symptoms. Furthermore, higher LS measurements were significantly associated with illness severity like pneumonia, need for mechanical ventilation, and even death. CONCLUSION: Transient elastography is a useful and non-invasive tool to assess onset and severity of acute liver injury in patients with COVID-19 patients. Increased LS seems to be predictive for a more severe and complicated course of disease.

Combined Hyperbaric Oxygen Partial Pressure at 1.4 Bar with Infrared Radiation: A Useful Tool To Improve Tissue Hypoxemia?

Tissue hypoxia contributes to the pathogenesis of several acute and chronic diseases. Hyperbaric oxygen therapy (HBO) and whole-body warming using low-temperature infrared technology (LIT) are techniques that might improve hypoxemia. Combining HBO and LIT as hyperbaric oxygen therapy combined with low-temperature infrared radiation (HBOIR) might be an approach that results in positive synergistic effects on oxygenation. LIT increases blood flow and could reduce HBO-induced vasoconstriction, and hyperoxia could compensate for the increased metabolic oxygen requirements mediated by LIT. Both LIT and HBO increase the oxygen diffusion distance in the tissues. HBOIR at 0.5 bar has been shown to be safe and feasible. However, physiological responses and the safety of HBOIR at an increased oxygen (O2) partial pressure of 1.4 bar or 2.4 atmospheres absolute (ATA) still need to be determined. The hope is that should HBOIR at an increased oxygen partial pressure of 1.4 bar be safe, future studies to examine its efficacy in patients with clinical conditions, which include peripheral arterial disease (PAD) or wound healing disorders, will follow. The results of pilot studies have shown that HBOIR at an overload pressure is safe and well tolerated in healthy participants but can generate moderate cardiovascular changes and an increase in body temperature. From the findings of this pilot study, due to its potential synergistic effects, HBOIR could be a promising tool for the treatment of human diseases associated with hypoxemia.

Carotid sinus syndrome: a case report of an unusual presentation of cardiac arrest while diving.

BACKGROUND: Carotid sinus syndrome (CSS) is an exaggerated response to carotid sinus baroreceptor stimulation, which may result in hypotension, prolonged asystole, and subsequently transient loss of consciousness due to cerebral hypoperfusion. However, this commonly benign syndrome may have lethal consequences under certain circumstances such as scuba diving. CASE SUMMARY: We report the case of a trained 73-year-old male diver, who survived an almost fatal diving accident without any neurological deficits due to cardiac arrest under water. After recovery and intensive diagnostics in the local hospital, the origin of cardiac arrest remained unclear. However, after referral to our tertiary care centre CSS could be diagnosed by provoking syncope and asystole with carotid sinus massage (CSM). Consequently, a leadless pacing system was implanted and his medical diving fitness could then be recertified. DISCUSSION: In conclusion, CSS may be an underdiagnosed cause of loss of consciousness. Thus, screening for CSS by CSM should be included in medical exams in senior athletes and specifically in senior divers.

Helicopter-based in-water resuscitation with chest compressions: a pilot study.

BACKGROUND: Drowning is a relevant worldwide cause of severe disability and death. The delay of ventilations and chest compressions is a crucial problem in drowning victims. Hence, a novel helicopter-based ALS rescue concept with in-water ventilation and chest compressions was evaluated. METHODS: Cardio pulmonary resuscitation (CPR) and vascular access were performed in a self-inflating Heliboat platform in an indoor wave pool using the Fastrach intubating laryngeal mask, the Oxylator resuscitator, Lund University Cardiopulmonary Assist System (LUCAS) chest compression device and EZ-IO intraosseous power drill. The time requirement and physical exertion on a Visual Analogue Scale (VAS) were compared between a procedure without waves and with moderate swell. RESULTS: Measurement of the elapsed time of the various stages of the procedure did not reveal significant differences between calm water and swell: Ventilation was initiated after 02:48 versus 03:02 and chest compression after 04:20 versus 04:18 min; the intraosseous cannulisation was completed after 05:59 versus 06:30 min after a simulated jump off the helicopter. The attachment of the LUCAS to the mannequin and the intraosseous cannulisation was rated significantly more demanding on the VAS during swell conditions. CONCLUSIONS: CPR appears to be possible when performed in a rescue platform with special equipment. The novel helicopter-based strategy appears to enable the rescuers to initiate CPR in an appropriate length of time and with an acceptable amount of physical exertion for the divers. The time for the helicopter to reach the patient will have to be very short to minimise neurological damage in the drowning victim.

Diagnostic imaging of gout: comparison of high-resolution US versus conventional X-ray.

The aim was to compare X-ray and ultrasound (US) in diagnosing gout. In a prospective study, 105 consecutive patients with clinical suspicion of gout underwent conventional X-ray und high-resolution US in order to help in arriving at a definite diagnosis. X-ray findings suggestive of gout included soft-tissue opacifications with densities between soft tissue and bone, articular and periarticular bone erosions, and osteophytes at the margins of opacifications or erosions. US findings suggestive of gout included bright stippled foci and hyperechoic soft-tissue areas. Fifty-five patients had a definite diagnosis of gout (102 involved sites), 31 patients were diagnosed as having another disease (59 involved sites), and 19 patients were excluded from the study because a definite diagnosis could not be established. X-ray suggested gout with a sensitivity of 31% (32/102) and a specificity of 93% (55/59), whereas US suggested gout with a sensitivity of 96% (98/102) and a specificity of 73% (43/59). US was much more sensitive than conventional X-ray but less specific. Our data show that US often provided additional diagnostic information in patients with clinical suspicion of gout when laboratory findings and X-ray results were negative or inconclusive and should therefore be used in these cases.

Patella resurfacing: no benefit for the long-term outcome of total knee arthroplasty. A 10- to 16.3-year follow-up.

A follow-up of more than 10 years among patients who have undergone a total knee arthroplasty (TKA) was performed to determine the significance of patella resurfacing for the long-term outcome. The clinical outcome was assessed by the Knee Society Score (KSS), and the radiological outcome was determined based on the Knee Society Roentgenographic Evaluation System. The patella was preserved in 21 knees and resurfaced in 44 knees. The mean follow-up time was 11.6 years (range 10-16.3 years). There was no significant difference in the clinical outcome between the knees with patella resurfacing (knee points: mean 85.3 +/-12.9, function points: mean 70.3 +/- 23.4) and the knees with patella retention (knee points: mean 82.7 +/- 16.2, function points: mean 71.7 +/- 22.4; p = 0.58 for knee, and p = 0.83 for function points). There was also no significant difference in the radiological outcomes regarding the angles alpha, beta, Upsilon, delta, and valgus ( p > 0.05 for each variable). There was, however, a trend towards more lucencies in TKAs with a resurfaced patella on the tibia side in the anteroposterior view ( p = 0.052). Patellar complications were found more often in the resurfaced group (20.5%) than in the group without resurfacing (9.6%). The results indicate overall no advantage of patella resurfacing compared with patella retention in the long run.

Randomized double blind trial of an extract from the pentacyclic alkaloid-chemotype of uncaria tomentosa for the treatment of rheumatoid arthritis.

OBJECTIVE: To evaluate safety and clinical efficacy of a plant extract from the pentacyclic chemotype of Uncaria tomentosa (UT) in patients with active rheumatoid arthritis (RA). METHODS: Forty patients undergoing sulfasalazine or hydroxychloroquine treatment were enrolled in a randomized 52 week, 2 phase study. During the first phase (24 weeks, double blind, placebo controlled), patients were treated with UT extract or placebo. In the second phase (28 weeks) all patients received the plant extract. RESULTS: Twenty-four weeks of treatment with the UT extract resulted in a reduction of the number of painful joints compared to placebo (by 53.2% vs 24.1%; p = 0.044). Patients receiving the UT extract only during the second phase experienced a reduction in the number of painful (p = 0.003) and swollen joints (p = 0.007) and the Ritchie Index (p = 0.004) compared to the values after 24 weeks of placebo. Only minor side effects were observed. CONCLUSION: This small preliminary study demonstrates relative safety and modest benefit to the tender joint count of a highly purified extract from the pentacyclic chemotype of UT in patients with active RA taking sulfasalazine or hydroxychloroquine.