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Page 1 of 6

  • Gas killing of rats: the effect of supplemental oxygen on aversion to carbon dioxide
  • RD Kirkden, L Niel, SA Stewart, DM Weary
  • Journal: Animal Welfare / Volume 17 / Issue 1 / February 2008
  • Published online by Cambridge University Press: 11 January 2023, pp. 79-87
  • View abstract

    High concentrations of carbon dioxide (CO2), used for killing laboratory rodents, are known to be more strongly aversive to rats than sweet food items are attractive. This study investigated whether the maintenance of a high oxygen (O2) concentration, using a gas mixture of 70% CO2 and 30% O2, would reduce aversion to CO2 during a gradual-fill procedure. Eight male Wistar rats, aged 10 months, were housed individually in an apparatus consisting of two cages, one higher than the other and joined by a tube. In a series of trials, subjects entered the lower cage for a reward of 20 sweet food items. The gas was turned on at the moment the rat started eating the reward items and flowed into the lower cage at a fixed rate. There were four treatments: 1) 100% CO2 at 14.5% cage volume min–1; 2) gas mixture at 14.5% min–1; 3) gas mixture at 21.0% min–1, which delivered CO2 at approximately 14.5% min–1 and 4) air, with each subject tested with each treatment four times. Measures of willingness to stay and eat in the lower cage (latency to stop eating, latency to leave and the number of reward items eaten) were much lower in all three gas treatments than in air, indicating that the CO2 and the CO2 + O2 mixture were both more strongly aversive than sweet food items were attractive. Comparing the gas mixture with 100% CO2, the latency to leave and the number of reward items eaten were slightly higher in the CO2 + O2 mixture at 21% min–1 than in CO2 at 14.5% min–1, indicating that the addition of O2 slightly reduced the aversiveness of CO2 in the gradual-fill procedure. This reduction is not enough to warrant recommending the use of CO2 + O2 mixtures for killing rats.

  • Chapter 7: - The Evolution of Complex Life
  • from Part I - Introduction to the Scientific Perspective on the Past
  • Brian Villmoare, University of Nevada, Las Vegas
  • Book: The Evolution of Everything
  • Published online: 03 November 2022
  • Print publication: 24 November 2022, pp 90-99
  • View extract

    Summary

    Plants are the Earth’s primary producers of oxygen, organic compounds, and easily convertible energy. The appearance of photosynthesis in chloroplast-bearing cyanobacteria set the stage for all later life, and is responsible for the oxygenation of the planet. This event is easily apparent in the geological record in the form of rust layers. Dense layers of water-borne organisms, each layer in a symbiotic relationship with the others, such as those seen at stagnant hot springs, likely represent the ancestral condition for later complex, multicellular organisms. This time period, between 1 and 2 billion years ago, is when Eukaryotes evolved, and the division of labor among the cells of Eukaryotes has allowed natural selection to work on different parts of a complex organism, allowing the adaptive diversity we see today in plants and animals. Critically, this time is when energy from the sun is first stored on earth in large amounts. In fact, these large sheets of cyanobacteria and algae have become stored in the geological record and, later, became the source of petroleum. So the fossil fuels of today represent hundreds of millions of years of stored photosynthetic energy, the source of which ultimately was the sun

  • Chapter 8 - Fundamentals of Cardiovascular Physiology
  • Edited by Daniel Rodger, Kevin Henshaw, Paul Rawling, Scott Miller
  • Book: Fundamentals of Operating Department Practice
  • Published online: 18 August 2022
  • Print publication: 08 September 2022, pp 81-88
  • View extract

    Summary

    This chapter provides a detailed overview of the cardiovascular system in the context of perioperative care. The cardiovascular system is responsible for the delivery of oxygen around the body and the return of this blood to the heart. This blood is then pumped to the lungs and back to the heart. The systemic and pulmonary circulations have a number of important differences between them. The heart beats repeatedly in a process known as the cardiac cycle, which has two distinct phases, systole, and diastole. The conduction system of the heart allows for the chambers of the heart to contract in a well-coordinated manner. Problems with the cardiovascular system occur frequently under anaesthesia and can have numerous causes, some of which are explored in this chapter.

  • Porterville Alternate Care Site Provision of Oxygen at COVID-19 Pandemic Peak
  • Lance Montauk
  • Journal: Disaster Medicine and Public Health Preparedness , First View
  • Published online by Cambridge University Press: 05 August 2022, pp. 1-5
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    During the COVID-19 pandemic peak, the author deployed twice to an emergency Alternate Care Site in Porterville, California. The provision of oxygen to patients there, as seen from a physician’s perspective, does not fully support the description in a recently published article of how the State of California approached oxygen logistics during the COVID-19 surge. To inform future planning, an adequate logistical assessment must include not only approaches for solving technical resource challenges, but also reliable numbers regarding end-user resource utilization, and non-utilization, as well as program costs, benefits, and unintended consequences.

  • Oxygen, a key signalling factor in the control of seed germination and dormancy
  • Françoise Corbineau
  • Journal: Seed Science Research / Volume 32 / Issue 3 / September 2022
  • Published online by Cambridge University Press: 28 June 2022, pp. 126-136
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    Oxygen is a major factor of seed germination since it allows resumption of respiration and subsequent metabolism reactivation during seed imbibition, thus leading to the production of reducing power and ATP. Most studies carried out in the 60s to 85s indicate that oxygen requirement depends on the species and is modulated by environmental factors. They have also demonstrated that the covering structures mainly inhibit germination by limiting oxygen supply to the embryo during imbibition through enzymatic oxidation of phenolic compounds by polyphenol oxidases (catechol oxidase and laccase) and peroxidases. Recent use of oxygen-sensitive microsensors has allowed to better characterize the oxygen diffusion in the seed and determine the oxygen content at the level of embryo below the covering structures. Here, I will also highlight the major data obtained over the last 30 years indicating the key role of oxygen in the molecular networks regulating seed germination and dormancy through (1) the hormonal balance (ethylene, ABA and GA), the hormone-signalling pathway and, in particular, the ABA sensitivity, (2) the emerging role of mitochondria in ROS production in hypoxia and (3) the involvement of the N-degron pathway in the turnover of proteins involved in seed tolerance to hypoxia.

  • Milk yield variation partially attributed to blood oxygen-mediated neutrophil activation in lactating dairy goats
  • Jie Cai, Shulin Liang, Yunyi Xie, Xinwei Zang, Luyi Jiang, Chao Miao, Jianxin Liu, Diming Wang
  • Journal: British Journal of Nutrition / Volume 129 / Issue 3 / 14 February 2023
  • Published online by Cambridge University Press: 23 May 2022, pp. 369-380
  • Print publication: 14 February 2023
  • View abstract

    Blood oxygen is an essential component for numerous biological processes of mammalian animals. Milk production of ruminants largely relies on the supply of nutrients, such as glucose, amino acids and fatty acids. To define the regulatory role of blood oxygen availability in regard to milk production, seventy-five healthy Guanzhong dairy goats with similar body weight, days in milk and parities were selected. For each animal, milk yield was recorded and milk sample was collected to determine compositions. Milk vein blood was collected to determine parameters including blood gas, physio-biochemistry and haematology. Another blood sample was prepared for transcriptome and RT-qPCR. Results showed that both pressure of oxygen (pO2) in the milk vein (positively) and numbers of neutrophils in mammary vein (negatively) were associated with milk yield of the animals. To learn the role of pO2 in blood cell functionality, twelve animals (six with higher yield (H-group) and six with lower yield (L-group)) from seventy-five goats were selected. Compared with animals in L-group, goats in H-group were higher in pO2 but lower in pCO2, lactate, lactate dehydrogenase activity and neutrophil abundance in milk vein, compared with L-group. The blood transcriptome analysis suggested that compared with L-group, animals in H-group were depressed in functionality including neutrophil activation and metabolic pathways including glycolysis, NF-κB and HIF-1. Our result revealed that lower milk production could be associated with neutrophil activation responding to low pO2 in the mammary vein. In the meantime, we highlighted the potential importance of blood oxygen as a milk yield regulator.

  • Novel Negative Pressure Procedural Tent Reduces Aerosolized Particles in a Simulated Prehospital Setting
  • Nathaniel Hunt, Spencer Masiewicz, Logan Herbert, Benjamin Bassin, Christine Brent, Nathan L. Haas, Mohamad Hakam Tiba, Jon Lillemoen, Mark J. Lowell, Isabel Lott, Matthew Basinger, Graham Smith, Kevin R. Ward
  • Journal: Prehospital and Disaster Medicine / Volume 37 / Issue 3 / June 2022
  • Published online by Cambridge University Press: 05 April 2022, pp. 383-389
  • Print publication: June 2022
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    Background/Objective:

    The coronavirus disease 2019 (COVID-19) pandemic has challenged the ability of Emergency Medical Services (EMS) providers to maintain personal safety during the treatment and transport of patients potentially infected. Increased rates of COVID-19 infection in EMS providers after patient care exposure, and notably after performing aerosol-generating procedures (AGPs), have been reported. With an already strained workforce seeing rising call volumes and increased risk for AGP-requiring patient presentations, development of novel devices for the protection of EMS providers is of great importance.

    Based on the concept of a negative pressure room, the AerosolVE BioDome is designed to encapsulate the patient and contain aerosolized infectious particles produced during AGPs, making the cabin of an EMS vehicle safer for providers. The objective of this study was to determine the efficacy and safety of the tent in mitigating simulated infectious particle spread in varied EMS transport platforms during AGP utilization.

    Methods:

    Fifteen healthy volunteers were enrolled and distributed amongst three EMS vehicles: a ground ambulance, an aeromedical-configured helicopter, and an aeromedical-configured jet. Sodium chloride particles were used to simulate infectious particles and particle counts were obtained in numerous locations close to the tent and around the patient compartment. Counts near the tent were compared to ambient air with and without use of AGPs (non-rebreather mask, continuous positive airway pressure [CPAP] mask, and high-flow nasal cannula [HFNC]).

    Results:

    For all transport platforms, with the tent fan off, the particle generator alone, and with all AGPs produced particle counts inside the tent significantly higher than ambient particle counts (P <.0001). With the tent fan powered on, particle counts near the tent, where EMS providers are expected to be located, showed no significant elevation compared to baseline ambient particle counts during the use of the particle generator alone or with use of any of the AGPs across all transport platforms.

    Conclusion:

    Development of devices to improve safety for EMS providers to allow for use of all available therapies to treat patients while reducing risk of communicable respiratory disease transmission is of paramount importance. The AerosolVE BioDome demonstrated efficacy in creating a negative pressure environment and workspace around the patient and provided significant filtration of simulated respiratory droplets, thus making the confined space of transport vehicles potentially safer for EMS personnel.

  • Quality of haylage of Brachiaria brizantha with different contents of dry matter in the storage
  • F. L. dos S. Ezequiel, R. L. Edvan, F. L. de Azevedo, P. C. B. de Farias, R. R. do Nascimento, D. M. A. Barros, M. J. de Araújo, R. de S. Miranda, L. R. Bezerra, E. M. Santos
  • Journal: The Journal of Agricultural Science / Volume 160 / Issue 1-2 / February 2022
  • Published online by Cambridge University Press: 21 March 2022, pp. 45-54
  • View abstract

    The purpose of this study was to evaluate the quality of Marandu grass (Brachiaria brizantha) haylage according to different dry matter (DM) contents in storage. The design adopted was completely randomized with four treatments and five replications. The treatments were DM contents of the plant at the moment of storage (in natura, 30–40, 40–50 and 50–60% DM). The analyses to assess the quality of the haylage were performed after 90 days of storage. The chemical composition, microbiological population, gas quantification, pH, N-NH3, volatile fatty acids, soluble carbohydrates (CHO) and the aerobic stability were evaluated. The means were compared through the Tukey's test and linear regression. The treatment with 50–60% DM presented the highest DM and CHO contents which were 563.8 and 42.0 g/kg, respectively. There was a higher presence of oxygen in the haylage of in natura material, which was 4.8%. There was no difference between treatments for the population of lactic acid bacteria; however, the treatment with 50–60% DM had the highest concentration of enterobacteria. The haylage with 30–40% DM and 50–60% DM presented high concentrations of acetic acid. There was no break in aerobic stability for any treatment within 120 h after opening the bales. There was a smaller amount of N-NH3 in treatments with 40–50% DM and 50–60% DM. The Marandu grass with a DM content of 50–60% for haylage making demonstrated better quality characterization of conserved forage.

  • Gaps in Prehospital Care for Patients Exposed to a Chemical Attack – A Systematic Review
  • Stephane Bourassa, Emmanuelle Paquette-Raynard, Daniel Noebert, Marc Dauphin, Pelumi Samuel Akinola, Jason Marseilles, Philippe Jouvet, Jacinthe Leclerc
  • Journal: Prehospital and Disaster Medicine / Volume 37 / Issue 2 / April 2022
  • Published online by Cambridge University Press: 11 March 2022, pp. 230-239
  • Print publication: April 2022
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    Introduction:

    The survivability of mass casualties exposed to a chemical attack is dependent on clinical knowledge, evidence-based practice, as well as protection and decontamination capabilities. The aim of this systematic review was to identify the knowledge gaps that relate to an efficient extraction and care of mass casualties caused by exposure to chemicals.

    Methods:

    This systematic review was conducted from November 2018 through September 2020 in compliance with Cochrane guidelines. Five databases were used (MEDLINE, Web of Science Core Collection, Embase, Cochrane, and CINAHL) to retrieve studies describing interventions performed to treat victims of chemical attacks (protection, decontamination, and treatment). The outcomes were patient’s health condition leading to his/her stabilization (primary) and death (secondary) due to interventions applied (medical, protection, and decontamination).

    Results:

    Of the 2,301 papers found through the search strategy, only four publications met the eligibility criteria. According to these studies, the confirmed chemical poisoning cases in acute settings resulting from the attacks in Matsumoto (1994), Tokyo (1995), and Damascus (2014) accounted for 1,333 casualties including 11 deaths. No study reported comprehensive prehospital clinical data in acute settings. No mention was made of the integration of specialized capabilities in medical interventions such as personal protective equipment (PPE) and decontamination to prevent a secondary exposure. Unfortunately, it was not possible to perform the planned meta-analysis.

    Conclusions:

    This study demonstrated gaps in clinical knowledge application regarding the medical extraction of casualties exposed during a chemical attack. Further research is required to optimize clinical practice integrating mixed capabilities (protection and decontamination) for the patient and medical staff.

  • Novel Negative Pressure Helmet Reduces Aerosolized Particles in a Simulated Prehospital Setting
  • Nathaniel Hunt, Spencer Masiewicz, Logan Herbert, Benjamin Bassin, Christine Brent, Nathan L. Haas, Mohamad Hakam Tiba, Jon Lillemoen, Mark J. Lowell, Isabel Lott, Matthew Basinger, Graham Smith, Kevin R. Ward
  • Journal: Prehospital and Disaster Medicine / Volume 37 / Issue 1 / February 2022
  • Published online by Cambridge University Press: 31 January 2022, pp. 33-38
  • Print publication: February 2022
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    Background/Objective:

    The coronavirus disease 2019 (COVID-19) pandemic has created challenges in maintaining the safety of prehospital providers caring for patients. Reports have shown increased rates of Emergency Medical Services (EMS) provider infection with COVID-19 after patient care exposure, especially while utilizing aerosol-generating procedures (AGPs). Given the increased risk and rising call volumes for AGP-necessitating complaints, development of novel devices for the protection of EMS clinicians is of great importance.

    Drawn from the concept of the powered air purifying respirator (PAPR), the AerosolVE helmet creates a personal negative pressure space to contain aerosolized infectious particles produced by patients, making the cabin of an EMS vehicle safer for providers. The helmet was developed initially for use in hospitals and could be of significant use in the prehospital setting. The objective of this study was to determine the efficacy and safety of the helmet in mitigating simulated infectious particle spread in varied EMS transport platforms during AGP utilization.

    Methods:

    Fifteen healthy volunteers were enrolled and distributed amongst three EMS vehicles: a ground ambulance, a medical helicopter, and a medical jet. Sodium chloride particles were used to simulate infectious particles, and particle counts were obtained in numerous locations close to the helmet and around the patient compartment. Counts near the helmet were compared to ambient air with and without use of AGPs (non-rebreather mask [NRB], continuous positive airway pressure mask [CPAP], and high-flow nasal cannula [HFNC]).

    Results:

    Without the helmet fan on, the particle generator alone and with all AGPs produced particle counts inside the helmet significantly higher than ambient particle counts. With the fan on, there was no significant difference in particle counts around the helmet compared to baseline ambient particle counts. Particle counts at the filter exit averaged less than one despite markedly higher particle counts inside the helmet.

    Conclusion:

    Given the risk to EMS providers by communicable respiratory diseases, development of devices to improve safety while still enabling use of respiratory therapies is of paramount importance. The AerosolVE helmet demonstrated efficacy in creating a negative pressure environment and provided significant filtration of simulated respiratory droplets, thus making the confined space of transport vehicles potentially safer for EMS personnel.

  • Adipokines: inflammation and the pleiotropic role of white adipose tissue
  • Paul Trayhurn
  • Journal: British Journal of Nutrition / Volume 127 / Issue 2 / 28 January 2022
  • Published online by Cambridge University Press: 12 January 2022, pp. 161-164
  • Print publication: 28 January 2022
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    I had been working on the endocrine and signalling role of white adipose tissue (WAT) since 1994 following the identification of the ob (Lep) gene(1), this after some 15 years investigating the physiological role of brown adipose tissue. The ob gene, a mutation in which it is responsible for the profound obesity of ob/ob (Lepob/Lepob) mice, is expressed primarily in white adipocytes and encodes the pleiotropic hormone leptin. The discovery of this adipocyte hormone had wide-ranging implications, including that white fat has multiple functions that far transcend the traditional picture of a simple lipid storage organ.

  • 3 - The Origin of Animals and the Emergence of the Earth System
  • Michael Hannah, Victoria University of Wellington
  • Book: Extinctions
  • Published online: 01 September 2021
  • Print publication: 16 September 2021, pp 49-75
  • View extract

    Summary

    The continuation of life on Earth relies on the Earth System maintaining planetary conditions in an equilibrium suitable for its continuation. But the Earth System did not just spring into existence – it developed slowly as complex life evolved and modern-style ecosystems appeared. In this chapter I review the history of early life, beginning with the oldest Snowball Earth event (about 700 million years ago) through to the Cambrian Explosion (about 480 million years ago). A field trip down Brachina Creek in the Flinders Ranges of South Australia that start in the early Cambrian and ends at the boundary of the Cryogenian and Ediacaran Periods sets the scene for the discussion. Intimately associated with the evolution of complex organisms and the appearance of the Earth System is the story of oxygen. This history of this important gas and its role in the evolution of life is briefly reviewed.

  • Hyperoxia in depression
  • R. Belmaker, Y. Bloch, P. Shvartzman, P. Romem, Y. Bersudsky, A. Azab
  • Journal: European Psychiatry / Volume 64 / Issue S1 / April 2021
  • Published online by Cambridge University Press: 13 August 2021, pp. S688-S689
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    Introduction

    Several studies of normobaric hyperoxia in some neurological conditions have demonstrated clinical benefits. Oxygen enriched air may increase oxygen pressure in brain tissue and have biochemical effects such as on brain erythropoietin gene expression, even in patients without lung disease.

    Objectives

    This pilot, randomized, double-blind study examined the efficacy of normobaric hyperoxia as a treatment for depression.

    Methods

    Fifty-five consenting patients aged 18-65 years with mild to moderate depression were included in the study. Participants underwent a psychiatric inclusion assessment and a clinical evaluation by a psychiatric nurse at baseline, 2 and 4 weeks after commencement of study intervention. Participants were randomly assigned to normobaric hyperoxia of 35% fraction of inspired oxygen or 21% fraction of inspired oxygen (room air), through a nasal tube, for 4 weeks, during the night. Patients were rated blindly using the Hamilton Rating Scale for Depression (HRSD); Clinical Global Impression (CGI) questionnaire; Sheehan Disability Scale (SDS).

    Results

    The present study showed a significant improvement in HRSD (p<0.0001), CGI (p<0.01) and in SDS (p<0.05) among patients with depression who were treated with oxygen-enriched air, as compared to patients who were treated with room air. In CGI, 69% of the patients who were treated with oxygen-enriched air improved compared to 23% patients who were treated with room air.

    Conclusions

    This small pilot study showed a beneficial effect of normobaric hyperoxia on some symptoms of depression.

    Disclosure

    No significant relationships.

Reconstructing Precambrian pCO2 and pO2 Using Paleosols
  • Reconstructing Precambrian pCO2 and pO2 Using Paleosols
  • Nathan D. Sheldon, Ria L. Mitchell, Rebecca M. Dzombak
  • Published online: 02 February 2021
  • Print publication: 04 March 2021
  • View abstract
    Paleosols formed in direct contact with the Earth's atmosphere, so they can record the composition of the atmosphere through weathering processes and products. Herein we critically review a variety of different approaches for reconstructing atmospheric O2 and CO2 over the past three billion years. Paleosols indicate relatively low CO2 over that time, requiring additional greenhouse forcing to overcome the 'faint young Sun' paradox in the Archean and Mesoproterozoic, as well as low O2 levels until the Neoproterozoic. Emerging techniques will revise the history of Earth's atmosphere further and may provide a window into atmospheric evolution on other planets.
  • Stable isotopes confirm the Banwell Bone Cave Mammal Assemblage Zone represents an MIS 5 fauna
  • Rhiannon E. Stevens, Hazel Reade
  • Journal: Quaternary Research / Volume 101 / May 2021
  • Published online by Cambridge University Press: 20 January 2021, pp. 245-255
  • View abstract

    The position of the Banwell Bone Cave mammal assemblage zone (MAZ) in the mammalian biostratigraphy of the British Isles has been the focus of debate for decades. Dominated by fauna typical of cold environments it was originally linked to the marine oxygen isotope stage (MIS) 4 stadial (ca. 72–59 ka). Subsequently it was argued that the Banwell Bone Cave MAZ more likely relates to the temperate interstadial of MIS 5a (ca. 86–72 ka). It is envisioned that “cold fauna” such as bison and reindeer moved into Britain during stadial MIS 5b (ca. 90 ka) and were subsequently isolated by the rising sea level during MIS 5a. Here we investigate environmental conditions during the Banwell Bone Cave MAZ using bone collagen δ13C and δ15N and tooth enamel δ18O and δ13C isotope analysis. We analyse bison and reindeer from the MAZ type-site, Banwell Bone Cave. Our results show unusually high δ15N values, which we ascribe to arid conditions within a temperate environment. Palaeotemperature estimates derived from enamel δ18O indicate warm temperatures, similar to present day. These results confirm that the Banwell Bone Cave MAZ relates to a temperate interstadial and supports its correlation to MIS 5a rather than MIS 4.

Cerium Anomalies and Paleoredox
  • Cerium Anomalies and Paleoredox
  • Rosalie Tostevin
  • Published online: 02 January 2021
  • Print publication: 25 February 2021
  • View abstract
    Ce anomalies track changes in oxygen availability due to the anomalous redox-sensitivity of Ce compared with the other rare earth elements. The proxy systematics have been calibrated experimentally as well as in modern anoxic water bodies. Ce anomalies are unique because they track intermediate manganous conditions, rather than fully anoxic conditions. In addition, they are sensitive to local–regional redox conditions, and can be analysed in chemical sediments such as carbonate rocks. This makes them especially useful as a tool to track local oxygen distribution in shallow shelf environments, where biodiversity is highest. This review focusses on the systematics of the Ce anomaly proxy, the preservation and extraction of the signal in sedimentary rocks, and the potential applications of the proxy.
  • Transnasal humidified rapid-insufflation ventilatory exchange (‘THRIVE’) in the coronavirus disease 2019 pandemic
  • S Y Hey, P Milligan, R M Adamson, I J Nixon, A F McNarry
  • Journal: The Journal of Laryngology & Otology / Volume 135 / Issue 1 / January 2021
  • Published online by Cambridge University Press: 07 January 2021, pp. 86-87
  • Print publication: January 2021
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    Background

    Since the start of the coronavirus disease 2019 pandemic, transnasal humidified rapid-insufflation ventilatory exchange (‘THRIVE’) has been classified as a high-risk aerosol-generating procedure and is strongly discouraged, despite a lack of conclusive evidence on its safety.

    Methods

    This study aimed to investigate the safety of transnasal humidified rapid-insufflation ventilatory exchange usage and its impact on staff members. A prospective study was conducted on all transnasal humidified rapid-insufflation ventilatory exchange cases performed in our unit between March and July 2020.

    Results

    During the study period, 18 patients with a variety of airway pathologies were successfully managed with transnasal humidified rapid-insufflation ventilatory exchange. For each case, 7–10 staff members were present. Appropriate personal protective equipment protocols were strictly implemented and adhered to. None of the staff involved reported symptoms or tested positive for coronavirus disease 2019, up to at least a month following their exposure to transnasal humidified rapid-insufflation ventilatory exchange.

    Conclusion

    With strictly correct personal protective equipment use, transnasal humidified rapid-insufflation ventilatory exchange can be safely employed for carefully selected patients in the current pandemic, without jeopardising the health and safety of the ENT and anaesthetic workforce.

  • Chapter 5 - Supportive Care during Acute Cerebral Ischaemia
  • from Part III - Acute Treatment of Ischaemic Stroke and Transient Ischaemic Attack
  • Edited by Jeffrey L. Saver, Graeme J. Hankey, University of Western Australia, Perth
  • Book: Stroke Prevention and Treatment
  • Published online: 15 December 2020
  • Print publication: 10 December 2020, pp 77-97
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    Summary

    Whereas only a minority of acute ischaemic stroke patients are eligible to reperfusion therapies, all can benefit from optimized supportive care to minimize acute stroke complications. Continuous pulse oximetry monitoring is recommended, and supplemental oxygen given as needed to maintain saturation>94%. During the first 24 hours after onset, when collateral dependence is greatest, blood pressure lowering may best be avoided, unless SBP >220 mm Hg, thrombolytics have been administered, or cardiac or other comorbidities are present; thereafter, gradual blood pressure lowering may safely be started. Initial fluid management should aim for normovolemia, using isotonic fluids; if substantial brain oedema develops, hypertonic fluids can be helpful. Electrolyte imbalances should be corrected and the underlying cause identified and treated. Extremely low and high blood glucose deviations should be avoided; if hyperglycaemia is present, treatment using a subcutaneous insulin sliding scale of moderate intensity is appropriate. Simple formal swallow screening should be performed early in all ischaemic stroke patients. When swallowing is impaired, initiating feeding via NG tube is reasonable within the first 2–3 days after onset. Temperature should be monitored and, if fever develops, antiyretic therapy started immediately and the cause identified and treated. For bladder dysfunction, an indwelling catheter should be avoided if possible to reduce infection rates. Hydration and passive/active movement of paretic extremities are important to prevent venous thromboembolism. In patients with reduced mobility, intermittent pneumatic compression devices should be employed. It is reasonable to use pharmacological thromboprophylaxis in patients at high risk of DVT (e.g. immobile, history of prior venous thromboembolism) and low risk of intracranial hemorrhage (e.g. small infarct less than 3 cm in diameter), and subcutaneous low-molecular-weight heparins are somewhat more effective than unfractionated heparin. Initial management of delirium should include non-pharmacological behavioral measures, including periodic verbal reassurances and reorientation, providing rooms with windows and clocks, facilitating sensory input with eyeglasses and hearing aids, and promoting a usual sleep-wake cycle.

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