Local Anesthetic Systemic Toxicity Joint Management in the Prehospital Environment: A Case Report.

Local anesthetic systemic toxicity (LAST) is a potentially life-threatening complication that may occur after local anesthetic injection. After reaching the systemic circulation, cardiovascular and central nervous system derangements may appear, with potentially fatal complications if left untreated. The pillars for LAST treatment are advanced life support measures, airway and seizure management, and a 20% lipid emulsion intravenous administration. When occurring in the prehospital setting, LAST is difficult to recognize, mostly because of its features overlapping with other acute conditions. Prompt treatment is also challenging because lipid emulsion may not be routinely carried on emergency vehicles. This article reports a case of LAST occurring in a dental ambulatory located in a remote location within the Italian Alps in which effective communication among different components of the same regional health care system (dispatch center, prehospital teams, and hospital network) led to fast lipid emulsion retrieval en route and on-site toxicity resolution. This case can inspire future operational changes, such as antidote networks available to prehospital emergency medicine crews, avoiding unnecessary deployment of antidotes on ambulances or helicopters, which is difficult to preserve without increasing management costs. However, to be established, such a network would need protocols to facilitate antidote retrieval, training focused on toxidromes recognition, and improved communication skills among different professionals involved in prehospital emergency medicine.

Dopamine/BDNF loss underscores narcosis cognitive impairment in divers: a proof of concept in a dry condition.

PURPOSE: Divers can experience cognitive impairment due to inert gas narcosis (IGN) at depth. Brain-derived neurotrophic factor (BDNF) rules neuronal connectivity/metabolism to maintain cognitive function and protect tissues against oxidative stress (OxS). Dopamine and glutamate enhance BDNF bioavailability. Thus, we hypothesized that lower circulating BDNF levels (via lessened dopamine and/or glutamate release) underpin IGN in divers, while testing if BDNF loss is associated with increased OxS. METHODS: To mimic IGN, we administered a deep narcosis test via a dry dive test (DDT) at 48 msw in a multiplace hyperbaric chamber to six well-trained divers. We collected: (1) saliva samples before DDT (T0), 25 msw (descending, T1), 48 msw (depth, T2), 25 msw (ascending, T3), 10 min after decompression (T4) to dopamine and/or reactive oxygen species (ROS) levels; (2) blood and urine samples at T0 and T4 for OxS too. We administered cognitive tests at T0, T2, and re-evaluated the divers at T4. RESULTS: At 48 msw, all subjects experienced IGN, as revealed by the cognitive test failure. Dopamine and total antioxidant capacity (TAC) reached a nadir at T2 when ROS emission was maximal. At decompression (T4), a marked drop of BDNF/glutamate content was evidenced, coinciding with a persisting decline in dopamine and cognitive capacity. CONCLUSIONS: Divers encounter IGN at - 48 msw, exhibiting a marked loss in circulating dopamine levels, likely accounting for BDNF-dependent impairment of mental capacity and heightened OxS. The decline in dopamine and BDNF appears to persist at decompression; thus, boosting dopamine/BDNF signaling via pharmacological or other intervention types might attenuate IGN in deep dives.

Effects of short-term unloading and active recovery on human motor unit properties, neuromuscular junction transmission and transcriptomic profile.

Electrophysiological alterations of the neuromuscular junction (NMJ) and motor unit potential (MUP) with unloading are poorly studied. We aimed to investigate these aspects and the underlying molecular mechanisms with short-term unloading and active recovery (AR). Eleven healthy males underwent a 10-day unilateral lower limb suspension (ULLS) period, followed by 21-day AR based on resistance exercise. Quadriceps femoris (QF) cross-sectional area (CSA) and isometric maximum voluntary contraction (MVC) were evaluated. Intramuscular electromyographic recordings were obtained during 10% and 25% MVC isometric contractions from the vastus lateralis (VL). Biomarkers of NMJ molecular instability (serum c-terminal agrin fragment, CAF), axonal damage (neurofilament light chain) and denervation status were assessed from blood samples and VL biopsies. NMJ and ion channel transcriptomic profiles were investigated by RNA-sequencing. QF CSA and MVC decreased with ULLS. Increased CAF and altered NMJ transcriptome with unloading suggested the emergence of NMJ molecular instability, which was not associated with impaired NMJ transmission stability. Instead, increased MUP complexity and decreased motor unit firing rates were found after ULLS. Downregulation of ion channel gene expression was found together with increased neurofilament light chain concentration and partial denervation. The AR period restored most of these neuromuscular alterations. In conclusion, the human NMJ is destabilized at the molecular level but shows functional resilience to a 10-day unloading period at least at relatively low contraction intensities. However, MUP properties are altered by ULLS, possibly due to alterations in ion channel dynamics and initial axonal damage and denervation. These changes are fully reversed by 21 days of AR. KEY POINTS: We used integrative electrophysiological and molecular approaches to comprehensively investigate changes in neuromuscular integrity and function after a 10-day unilateral lower limb suspension (ULLS), followed by 21 days of active recovery in young healthy men, with a particular focus on neuromuscular junction (NMJ) and motor unit potential (MUP) properties alterations. After 10-day ULLS, we found significant NMJ molecular alterations in the absence of NMJ transmission stability impairment. These findings suggest that the human NMJ is functionally resilient against insults and stresses induced by short-term disuse at least at relatively low contraction intensities, at which low-threshold, slow-type motor units are recruited. Intramuscular electromyography analysis revealed that unloading caused increased MUP complexity and decreased motor unit firing rates, and these alterations could be related to the observed changes in skeletal muscle ion channel pool and initial and partial signs of fibre denervation and axonal damage. The active recovery period restored these neuromuscular changes.

Implementation of a nurse-led alternate care site for the management of the surge of patients with COVID-19 in an Italian emergency department.

BACKGROUND: To accommodate and separate the large numbers of patients going to hospital with COVID-19, many EDs had to create new pathways for patients. We describe the outcomes of patients treated in a nurse-led alternate care site (ACS) at our hospital. METHODS: This was a retrospective study of outcomes of patients managed at the ACS of 'San Bassiano' Hospital ED, Bassano del Grappa, Italy between 9 March and 16 April 2020. Self-presenting patients aged 5 years and older, suspected of having COVID-19, were initially diverted to the ACS. Patients with a National Early Warning Score ≥5 or with a desaturation ≥4% after the walking test were sent back to the main ED COVID-19 path for further evaluation and medical attention and were not further followed up. In the ACS, patients received a CXR, blood samples and a nasopharyngeal swab to test for SARS-CoV-2, and were sent home. An emergency physician reviewed the results later and called the patient back 5-6 hours later with instructions to return for medical evaluation of abnormal findings, or to seek their general practitioner's attention. Patients received a follow-up phone call 15 days later to learn of their course. RESULTS: A total of 487 patients were fully managed in the ACS and discharged home. Of the 392 (80.5%) patients with no abnormalities after the workup and instructed to stay at home, 29 reattended the ED in the next 15 days, and 13 were admitted. Among the 95 patients asked to return and receive medical attention, 20 were admitted and of those discharged, 3 reattended the ED within 15 days. At 15 days, no patient was deceased or received invasive ventilation; one admitted patient received non-invasive ventilation. CONCLUSIONS: A nurse-led ACS diverted a substantial proportion of patients from main ED resources without associated negative clinical outcomes.

Critical Review and Meta-Analysis of Postoperative Sedation after Adult Cardiac Surgery: Dexmedetomidine Versus Propofol.

OBJECTIVE: To evaluate reports from the published literature of all randomized clinical trials (RCT) comparing postoperative sedation with dexmedetomidine versus propofol in adult patients, after open cardiac surgery. DESIGN: A computerized search on Medline, EMBASE, Web of Science, and Agency for Healthcare Research and Quality databases was completed through June 2020. Meta-analysis of all published RCT comparing dexmedetomidine versus propofol utilization in the postoperative phase, using the standard Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. SETTING: Assemblage and critical discussion of 11 RCTs comparing postoperative sedation from standard published reports from 2003 to 2019. PARTICIPANTS: The study comprised 1,184 patients and analyzed critical discussion of time-based parameters (time to extubation, intensive care unit length of stay, and hospital length of stay) and nontime-dependent factors (delirium, bradycardia, and hypotension). MEASUREMENTS AND MAIN RESULTS: Time to extubation was significantly reduced in the dexmedetomidine group (standardized mean difference [SMD] = -0.70, 95% confidence interval [CI] -0.98 to -0.42, p < 0.001); however, no difference in mechanical ventilation time was observed (SMD = -0.72, 95% CI -1.60 to 0.15, N.S.). Dexmedetomidine significantly reduced the intensive care unit length of stay (SMD = 0.23, 95% CI -1.06 to -0.16, p = 0.008), but this did not translate into a reduced hospital length of stay (SMD = -1.13, 95% CI -2.43 to 0.16, N.S). For nontime-dependent factors, incidence of delirium was unaffected between groups (odds ratio [OR]: 0.68, 95% CI 0.43-1.06, N.S), and higher rates of bradycardia (OR: 3.39, 95% CI: 1.20-9.55, p = 0.020) and hypotension (OR: 1.68, 95% CI 1.09-2.58, p = 0.017) were reported with propofol. CONCLUSIONS: Despite the ICU time advantages afforded by dexmedetomidine over propofol, the former did not seem to contribute to an overall reduction in hospital length of stay or improvement in postoperative outcomes of heart valve surgery and CABG patients.

The Role of Hyperbaric Oxygen Treatment for COVID-19: A Review.

The recent coronavirus disease 2019 (COVID-19) pandemic produced high and excessive demands for hospitalizations and equipment with depletion of critical care resources. The results of these extreme therapeutic efforts have been sobering. Further, we are months away from a robust vaccination effort, and current therapies provide limited clinical relief. Therefore, several empirical oxygenation support initiatives have been initiated with intermittent hyperbaric oxygen (HBO) therapy to overcome the unrelenting and progressive hypoxemia during maximum ventilator support in intubated patients, despite high FiO2. Overall, few patients have been successfully treated in different locations across the globe. More recently, less severe patients at the edge of impending hypoxemia were exposed to HBO preventing intubation and obtaining the rapid resolution of symptoms. The few case descriptions indicate large variability in protocols and exposure frequency. This summary illustrates the biological mechanisms of action of increased O2 pressure, hoping to clarify more appropriate protocols and more useful application of HBO in COVID-19 treatment.

Arterial blood gases in divers at surface after prolonged breath-hold.

PURPOSE: Adaptations during voluntary breath-hold diving have been increasingly investigated since these athletes are exposed to critical hypoxia during the ascent. However, only a limited amount of literature explored the pathophysiological mechanisms underlying this phenomenon. This is the first study to measure arterial blood gases immediately before the end of a breath-hold in real conditions. METHODS: Six well-trained breath-hold divers were enrolled for the experiment held at the "Y-40 THE DEEP JOY" pool (Montegrotto Terme, Padova, Italy). Before the experiment, an arterial cannula was inserted in the radial artery of the non-dominant limb. All divers performed: a breath-hold while moving at the surface using a sea-bob; a sled-assisted breath-hold dive to 42 m; and a breath-hold dive to 42 m with fins. Arterial blood samples were obtained in four conditions: one at rest before submersion and one at the end of each breath-hold. RESULTS: No diving-related complications were observed. The arterial partial pressure of oxygen (96.2 ± 7.0 mmHg at rest, mean ± SD) decreased, particularly after the sled-assisted dive (39.8 ± 8.7 mmHg), and especially after the dive with fins (31.6 ± 17.0 mmHg). The arterial partial pressure of CO2 varied somewhat but after each study was close to normal (38.2 ± 3.0 mmHg at rest; 31.4 ± 3.7 mmHg after the sled-assisted dive; 36.1 ± 5.3 after the dive with fins). CONCLUSION: We confirmed that the arterial partial pressure of oxygen reaches hazardously low values at the end of breath-hold, especially after the dive performed with voluntary effort. Critical hypoxia can occur in breath-hold divers even without symptoms.

Clinical and morphological effects of hyperbaric oxygen therapy in patients with interstitial cystitis associated with fibromyalgia.

BACKGROUND: Interstitial Cystitis (IC) is a debilitating disorder of the bladder, with a multifactorial and poorly understood origin dealing with microcirculation repeated damages. Also Fibromyalgia (FM) is a persistent disorder whose etiology is not completely explained, and its theorized alteration of pain processing can compromise the quality of life. Both these conditions have a high incidence of conventional therapeutic failure, but recent literature suggests a significant beneficial response to Hyperbaric Oxygen Therapy (HBOT). With this study, this study we evaluated the effects of HBOT on quality of life, symptoms, urodynamic parameters, and cystoscopic examination of patients suffering from both IC and FM. METHODS: We structured an observational clinical trial design with repeated measures (questionnaires, urodynamic test, and cystoscopy) conducted before and 6 months after a therapeutic protocol with hyperbaric oxygen for the treatment of patients suffering from both IC and FM. Patients were exposed to breathing 100% oxygen at 2 atm absolute (ATA) in a multiplace pressure chamber for 90 min using an oro-nasal mask. Patients undertook a cycle of 20 sessions for 5 days per week, and a second cycle of 20 sessions after 1 week of suspension. RESULTS: Twelve patients completed the protocol. Changes after HBOT were not significant, except for hydrodistension tolerance (mean pre-treatment: 409.2 ml; mean post-treatment: 489.2 ml; p < 0.05). A regression of petechiae and Hunner's ulcers was also noted 6 months after the completion of HBOT. CONCLUSIONS: Our study showed no improvement of symptoms, quality of life, and urodynamic parameters, except for hydrodistension, and a slight improvement in cystoscopic pattern. However, to date, we could not demonstrate the significance of overall results to justify the use of HBOT alone in patients with IC and FM. This observation suggests that additional studies are needed to better understand if HBOT could treat this subset of patients. TRIAL REGISTRATION: NCT03693001 ; October 2, 2018. Retrospectively registered.

Oxidative stress assessment in breath-hold diving.

PURPOSE: Breath-hold diving results in significant changes in blood gases' levels. Challenging variations in oxygen partial pressures may induce reactive oxygen species (ROS) production that exacerbate oxidative stress and, consequently, affect endothelial function. The aim of this study was to investigate the effects of breath-hold diving on oxidative stress damage, assessing ROS production. Nitric oxide metabolites, inducible nitric oxide synthase (iNOS), aminothiols, and renal function were evaluated too as markers of redox status and renal damage. METHODS: ROS production was assessed with electron paramagnetic resonance. Oxidative status values were measured at pre- and post-40 m dive in a deep swimming pool (Y-40) from six divers (mean age 46.6 ± 9.3 years; height 176 ± 4 cm; BMI 25 ± 2.9 kg/m2). RESULTS: Significant (p < 0.05) increases at post-dive of ROS production rate (0.158 ± 0.003 vs 0.195 ± 0.006 µmol min-1), lipid peroxidation (8-isoprostane: 375.67 ± 195.62 vs 420.49 ± 232.31 pg mg-1 creatinine), nitrate (27.91 ± 19.71 vs 30.80 ± 20.44 µM), iNOS (31.30 ± 4.52 vs 35.68 ± 6.72 IU mL-1) and neopterin concentration (96.20 ± 40.41 vs 118.76 ± 27.84 µmol mol-1 creatinine) were recorded. Conversely, the antioxidant capacity significantly decreased (3.423 ± 0.089 vs 3.015 ± 0.284 mM) after immersion. CONCLUSION: Overproduction of ROS and consequent oxidative damage to lipids of membrane and antioxidant capacity decreasing reflect also a hypoxic condition, which in the breath-hold diving typically occurs in the last few meters below the surface. iNOS produces NO in large quantities under the examined extreme conditions. Neopterin and creatinine concentration level increased, suggesting an "impairment of renal function" as a likely physiological response to PaO2 variations during dive activity.

Evaluation of chest ultrasound integrated teaching of respiratory system physiology to medical students.

Ultrasound imaging is a widely used diagnostic technique, whose integration in medical education is constantly growing. The aim of this study was to evaluate chest ultrasound usefulness in teaching respiratory system physiology, students' perception of chest ultrasound integration into a traditional lecture in human physiology, and short-term concept retention. A lecture about respiratory physiology was integrated with ultrasound and delivered to third-year medical students. It included basic concepts of ultrasound imaging and the physiology of four anatomic sectors of the body of a male volunteer, shown with a portable ultrasound device (pleural sliding, diaphragmatic movement, inferior vena cava diameter variations, cardiac movements). Students' perceptions of the integrated lecture were assessed, and attendance recorded. After 4 mo, four multiple-choice questions about respiratory physiology were administered during the normal human physiology examinations, and the results of students who attended the lesson and those of who did not were compared. One hundred thirty-four students attended the lecture. Most of them showed encouragement for the study of the subject and considered the ultrasound integrated lecture more interesting than a traditional one and pertinent to the syllabus. Exposed students achieved a better score at the examination and committed less errors than did nonexposed students. The chest ultrasound integrated lecture was appreciated by students. A possible association between the exposure to the lecture and short-term concept retention is shown by better performances of the exposed cohort at the examination. A systematic introduction of ultrasound into physiology traditional teaching will be promoted by the Ultrasound-Based Medical Education movement.

Cave canem: HBO2 therapy efficacy on Capnocytophaga canimorsus infections: a case series.

BACKGROUND: Dog bites are a frequent injury, but the incidence and type of lesions vary across countries. Although only few patients develop complications, the treatment of advanced injuries has a considerable medical, social and economic impact. A frequently isolated pathogen in dog bite wounds is Capnocytophaga canimorsus, a bacterium that can cause sepsis or meningitis. Hyperbaric oxygen (HBO2) therapy has been shown to be useful in treating anaerobic infections, most likely because it creates an inhospitable environment for the bacterium and enhances the patient's immune response. AIM: We present a case series of C. canimorsus infections treated with HBO2 in adjunction to antibiotic therapy. Furthermore, we tested the in vitro activity of ceftaroline against C. canimorsus, alone and in association with hyperbaric oxygen therapy. METHODS: We included nine (9) patients admitted to the surgery department of "A. Cardarelli" Hospital (Naples) after dog bite, from 2010 to 2016. All were initially treated with antibiotics and required transfer to the intensive care unit due to worsening conditions. C. canimorsus was isolated from wounds, and HBO2 therapy was administered in adjunction to antibiotics, until clinical improvement and microbiological test negativity. We tested the activity of hyperbaric oxygen therapy in adjunction to ceftaroline on cultured plates with C. canimorsus versus ceftaroline alone. Minimal inhibitory concentration was evaluated. CONCLUSIONS: Our findings confirm the utility of HBO2 therapy after biting injuries. Indeed, increased oxygen supply to the wound (as well as in vitro) may be toxic for bacteria, can improve healing and may improve the effectiveness of antibiotics.

Feasibility of chest ultrasound up to 42 m underwater.

After recent advancements, ultrasound has extended its applications from bedside clinical practice to wilderness medicine. Performing ultrasound scans in extreme environments can allow direct visualization of unique pathophysiological adaptations but can be technically challenging. This paper summarizes how a portable ultrasound apparatus was marinized to let scientific divers and sonographers perform ultrasound scans of the lungs underwater up to - 42 m. A metallic case protected the ultrasound apparatus inside; a frontal transparent panel with a glove allowed visualization and operation of the ultrasound by the diving sonographer. The inner pressure was equalized with environmental pressure through a compressed air tank connected with circuits similar to those used in SCUBA diving. Finally, the ultrasound probe exited the metallic case through a sealed aperture. No technical issues were reported after the first testing step and the real experiments.

Appropriateness of packed red blood cells transfusions in chronic anemic patients in the emergency department: the TRANSFUS-ED retrospective analysis.

Patients suffering from chronic anemia can benefit from scheduled transfusions of packed red blood cells (PRBCs), while urgent transfusions have specific indications. These patients frequently seek medical attention in the emergency department (ED), where they can be inappropriately transfused, but research in this field is limited. This study aimed to assess the appropriateness of PRBCs transfusions in chronic anemic patients in the ED. A retrospective analysis was performed on patients who accessed the ED of the Azienda Ospedaliera di Padova (Padova, Italy) between 2016 and 2019 and received PRBCs transfusions. Patients aged ≥ 18 years old and with chronic anemia were included, while those with acute anemia or admitted to the hospital after the transfusion were excluded. Chronic anemia was defined as satisfying one of the following in the past medical history: diagnosis of chronic anemia; two or more previous blood samplings demonstrating anemia; periodic transfusions. As primary outcome, the appropriateness of transfusions was assessed according to the American Association of Blood Banks (AABB) 2016 criteria, using the recommended threshold of 7 g/dL for hemodynamically stable adults and 8 g/dL for patients with pre-existing cardiovascular disease. Out of 1153 transfusions, 344 transfusions were included in the study. According to our criteria, 139 (40.4%) patients were inappropriately transfused, resulting in a total estimated cost of 54,528.71 € in the study period. This study showed that transfusions in chronic anemic patients are recurrent events in the ED and are frequently inappropriate. A possible explanation could be the lack of a well-structured primary care network granting periodic transfusions in ambulatory centers. In the future, implementing and improving chronic anemic patients' access to transfusion services through dedicated pathways could reduce the burden on the ED and also decrease costs.

Factors causing emergency medical care overload during heatwaves: A Delphi study.

Heatwaves pose an important risk for population health and are associated with an increased demand for emergency care. To find factors causing such overload, an online Delphi study included 15 experts in emergency medicine, disaster medicine, or public health. One open-ended question was delivered in the first round. After content analysis, the obtained statements were sent to the experts in two rounds to be rated on a 7-point linear scale. Consensus was defined as a standard deviation ≤ 1.0. Thirty-one statements were obtained after content analysis. The experts agreed on 18 statements, mostly focusing on the input section of patient processing and identifying stakeholders, the population, and primary care as targets of potential interventions. Additional dedicated resources and bed capacity were deemed important as per throughput and output sections, respectively. These findings could be used in the future to implement and test solutions to increase emergency healthcare resilience during heatwaves and reduce disaster risk due to climatic change.

Seasonal Oxy-Inflammation and Hydration Status in Non-Elite Freeskiing Racer: A Pilot Study by Non-Invasive Analytic Method.

Freeskiing is performed in an extreme environment, with significant physical effort that can induce reactive oxygen species (ROS) generation and dehydration. This study aimed to investigate the evolution of the oxy-inflammation and hydration status during a freeskiing training season with non-invasive methods. Eight trained freeskiers were investigated during a season training: T0 (beginning), T1-T3 (training sessions), and T4 (after the end). Urine and saliva were collected at T0, before (A) and after (B) T1-T3, and at T4. ROS, total antioxidant capacity (TAC), interleukin-6 (IL-6), nitric oxide (NO) derivatives, neopterin, and electrolyte balance changes were investigated. We found significant increases in ROS generation (T1A-B +71%; T2A-B +65%; T3A-B +49%; p < 0.05-0.01) and IL-6 (T2A-B +112%; T3A-B +133%; p < 0.01). We did not observe significant variation of TAC and NOx after training sessions. Furthermore, ROS and IL-6 showed statistically significant differences between T0 and T4 (ROS +48%, IL-6 +86%; p < 0.05). Freeskiing induced an increase in ROS production, which can be contained by antioxidant defense activation, and in IL-6, as a consequence of physical activity and skeletal muscular contraction. We did not find deep changes in electrolytes balance, likely because all freeskiers were well-trained and very experienced.

Relative hypoxemia at depth during breath-hold diving investigated through arterial blood gas analysis and lung ultrasound.

Pulmonary gas exchange in breath-hold diving (BHD) consists of a progressive increase in arterial partial pressures of oxygen ([Formula: see text]) and carbon dioxide ([Formula: see text]) during descent. However, recent findings have demonstrated that [Formula: see text] does not consistently rise in all subjects. This study aimed at verifying and explaining [Formula: see text] derangements during BHD analyzing arterial blood gases and searching for pulmonary alterations with lung ultrasound. After ethical approval, 14 fit breath-hold divers were included. Experiments were performed in warm water (temperature: 31°C). We analyzed arterial blood gases immediately before, at depth, and immediately after a breath-hold dive to -15 m of fresh water (mfw) and -42 mfw. Signs of lung interstitial edema and atelectasis were searched simultaneously with a marinized lung ultrasound. In five subjects (-15 mfw) and four subjects (-42 mfw), the [Formula: see text] at depth seems to decrease instead of increasing. [Formula: see text] and lactate showed slight variations. At depth, no lung ultrasound alterations were seen except in one subject (hypoxemia and B-lines at -15 mfw; B-lines at the surface). Lung interstitial edema was detected in 3 and 12 subjects after resurfacing from -15 to -42 mfw, respectively. Two subjects developed hypoxemia at depth and a small lung atelectasis (a focal pleural irregularity of triangular shape, surrounded by thickened B-lines) after resurfacing from -42 mfw. Current experiments confirmed that some BH divers can experience hypoxemia at depth. The hypothesized explanation for such a discrepancy is lung atelectasis, which could not be detected in all subjects probably due to limited time available at depth.NEW & NOTEWORTHY During breath-hold diving, arterial partial pressure of oxygen ([Formula: see text]) and arterial partial pressure of carbon dioxide ([Formula: see text]) are believed to increase progressively during descent, as explained by theory, previous end-tidal alveolar gas measurements, and arterial blood gas analysis in hyperbaric chambers. Recent experiments in real underwater environment found a paradoxical [Formula: see text] drop at depth in some divers. This work confirms that some breath-hold divers can experience hypoxemia at depth. The hypothesized explanation for such a discrepancy is lung atelectasis, as suggested by lung ultrasound findings.

Comparison between Arterial Blood Gases and Oxygen Reserve Index™ in a SCUBA Diver: A Case Report.

Hypoxia and hyperoxia are both worrisome issues potentially affecting SCUBA divers, but validated methods to monitor these two conditions underwater are still lacking. In this experiment, a volunteer SCUBA diver was equipped with a pulse oximeter to detect peripheral oxygen saturation (SpO2) and a device to monitor the oxygen reserve index (ORi™). ORi™ values were compared with arterial blood oxygen saturation (SaO2) and the partial pressure of oxygen (PaO2) obtained from the cannulated right radial artery at three steps: at rest out of water; at -15 m underwater after pedaling on a submerged bike; after resurfacing. SpO2 and ORi™ mirrored the changes in SaO2 and PaO2, confirming the expected hyperoxia at depth. To confirm the potential usefulness of an integrated SpO2 and ORi™ device, further studies are needed on a broader sample with different underwater conditions and diving techniques.

Hyperbaric Oxygen Therapy Counters Oxidative Stress/Inflammation-Driven Symptoms in Long COVID-19 Patients: Preliminary Outcomes.

Long COVID-19 patients show systemic inflammation and persistent symptoms such as fatigue and malaise, profoundly affecting their quality of life. Since improving oxygenation can oppose inflammation at multiple tissue levels, we hypothesized that hyperbaric oxygen therapy (HBOT) could arrest inflammation progression and thus relieve symptoms of COVID-19. We evaluated oxy-inflammation biomarkers in long COVID-19 subjects treated with HBOT and monitored with non-invasive methods. Five subjects (two athletes and three patients with other comorbidities) were assigned to receive HBOT: 100% inspired O2 at 2.4 ATA in a multiplace hyperbaric chamber for 90 min (three athletes: 15 HBOT × 5 days/wk for 3 weeks; two patients affected by Idiopathic Sudden Sensorineural Hearing Loss: 30 HBOT × 5 days/wk for 6 weeks; and one patient with osteomyelitis: 30 HBOT × 5 days/wk for week for 6 weeks and, after a 30-day break, followed by a second cycle of 20 HBOT). Using saliva and/or urine samples, reactive oxygen species (ROS), antioxidant capacity, cytokines, lipids peroxidation, DNA damage, and renal status were assessed at T1_pre (basal level) and at T2_pre (basal level after treatment), and the results showed attenuated ROS production, lipid peroxidation, DNA damage, NO metabolites, and inflammation biomarker levels, especially in the athletes post-treatment. Thus, HBOT may represent an alternative non-invasive method for treating long COVID-19-induced long-lasting manifestations of oxy-inflammation.

Knowledge Gaps and Research Priorities on the Health Effects of Heatwaves: A Systematic Review of Reviews.

Although extreme weather events have played a constant role in human history, heatwaves (HWs) have become more frequent and intense in the past decades, causing concern especially in light of the increasing evidence on climate change. Despite the increasing number of reviews suggesting a relationship between heat and health, these reviews focus primarily on mortality, neglecting other important aspects. This systematic review of reviews gathered the available evidence from research syntheses conducted on HWs and health. Following the PRISMA guidelines, 2232 records were retrieved, and 283 reviews were ultimately included. Information was extracted from the papers and categorized by topics. Quantitative data were extracted from meta-analyses and, when not available, evidence was collected from systematic reviews. Overall, 187 reviews were non-systematic, while 96 were systematic, of which 27 performed a meta-analysis. The majority evaluated mortality, morbidity, or vulnerability, while the other topics were scarcely addressed. The following main knowledge gaps were identified: lack of a universally accepted definition of HW; scarce evidence on the HW-mental health relationship; no meta-analyses assessing the risk perception of HWs; scarcity of studies evaluating the efficacy of adaptation strategies and interventions. Future efforts should meet these priorities to provide high-quality evidence to stakeholders.

Oxidative stress and motion sickness in one crew during competitive offshore sailing.

Competitive Offshore Ocean Sailing is a highly demanding activity in which subjects are exposed to psychophysical stressors for a long time. To better define the physiological adaptations, we investigated the stress response of subjects exposed to 3-days long ocean navigation with disruption of circadian rhythms. 6 male subjects were involved in the study and provided urine and saliva samples before setting sail, during a single day of inshore sailing, during 3-days long ocean navigation, and at the arrival, to measure oxidative stress, cortisol, nitric oxide metabolites (NOx) and metabolic response. Motion Sickness questionnaires were also administered during the navigation. The crew suffered a mean weight loss of 1.58 kg. After the long navigation, a significant increase in ROS production and decrease in total antioxidant capacity and uric acid levels were observed. Lipid peroxidation, NO metabolites, ketones, creatinine, and neopterin levels were also increased. Furthermore, a significant increase in cortisol levels was measured. Finally, we found a correlation between motion sickness questionnaires with the increase of NOx, and no correlation with cortisol levels. Physical and psychological stress response derived from offshore sailing resulted in increased oxidative stress, nitric oxide metabolites, and cortisol levels, unbalanced redox status, transient renal function impairment, and ketosis. A direct correlation between motion sickness symptoms evaluated through questionnaires and NOx levels was also found.