pH Management During Hypothermic Cardiopulmonary Bypass with Circulatory Arrest
Richard A. Jonas, Jane W. Newburger, Joseph J. Volpe, John W. Kirklin in Brain Injury and Pediatric Cardiac Surgery, 2019
Two strategies have been used in response to the pH shift during hypothermic bypass. From the 1960s to the late 1970s, the more popular strategy was the pH-stat strategy, in which carbon dioxide is added to the gas mixture in the oxygenator to compensate for the alkaline shift. The resulting respiratory acidosis causes the pH to remain constant at 7.40 as determined at the patient’s hypothermic body temperature. As measured at 37°C—as is standard in blood-gas analyzers, which warm the cold blood sample to 37°C to perform the analysis—there will appear to be an increasing respiratory acidosis as the temperature decreases. The alternative alpha-stat strategy does not compensate for the natural shift in pH. With the alpha-stat strategy the pH remains at 7.40 as measured at 37°C. Generally, pure oxygen is used as the gas mixture in the oxygenator.2
Palliative care
J. Richard Smith, Giuseppe Del Priore, Robert L. Coleman, John M. Monaghan in An Atlas of Gynecologic Oncology, 2018
Breathlessness may become more severe in the last weeks of life, and is often difficult to control. It has many potential causes including pleural effusion, pulmonary embolism, muscle weakness, anemia, pneumonia, chronic heart failure, chronic obstructive pulmonary disease, and/or psychological distress. Consideration should be given to treating reversible causes if the benefit of doing so outweighs the burden to the patient. The goal of symptomatic treatment is to improve the subjective sensation as experienced by the patient, rather than to improve abnormalities in blood gas or pulmonary function. Difficulty breathing is often associated with a high level of anxiety, which exacerbates the problem. Patients may need to reduce their expectations and adapt their home environment to make daily activities more manageable. General measures include ensuring that the patient is comfortable, upright positioning, and providing information and reassurance. Teaching breathing exercises can give some feeling of control. Oxygen can be helpful, especially where there is hypoxia, but similar effects can be achieved by a stream of air, which produces less practical difficulties. If there is some reversible airway obstruction, bronchodilators may be useful. Opioids can improve exercise tolerance in advanced airway limitation and reduce the sensation of breathlessness. Benzodiazepines are central sedatives and can also relieve the unpleasant feeling of dyspnea. Corticosteroids may be helpful where dyspnea results from a large tumor mass.
Adult Anaesthesia
John C Watkinson, Raymond W Clarke, Louise Jayne Clark, Adam J Donne, R James A England, Hisham M Mehanna, Gerald William McGarry, Sean Carrie in Basic Sciences Endocrine Surgery Rhinology, 2018
Before induction of anaesthesia, it is common to preoxygenate by administering 100% oxygen via a tight fitting face mask for two to three minutes. Perhaps counter-intuitively, breathing 100% oxygen in this way may not increase the oxygen content of the blood. This is because for most patients, the arterial blood is almost fully saturated with oxygen even when breathing room air, so breathing oxygen cannot really improve on this. Rather, the purpose of this manoeuvre is to wash out the nitrogen-rich air within the lungs and thereby increase the mass of oxygen within the alveolar compartment. A reservoir of oxygen is created that serves to delay the rate of desaturation during a subsequent apnoea. As an alternative, four successive vital capacity breaths of 100% oxygen over 30 seconds can provide effective preoxygenation.
The rise of mucormycosis in Covid-19 patients in India
Published in Expert Review of Anti-infective Therapy, 2022
Oxygen is used in industries for several purposes including welding, cutting, and other chemical and combustion applications. Given the dire need for oxygen in India, it is not surprising to note that huge quantity of industrial oxygen was diverted for medical use, and the oxygen cylinders used in industries were used to transport the oxygen to hospitals and health facilities. According to the WHO, medical-use oxygen is very different from industrial oxygen in purity and quality, and that the production, storage, and distribution processes involved with industrial oxygen could result in contamination [14]. For example, the industrial oxygen cylinders are inappropriate for medical use as these can be contaminated with impurities as a result of use of unclean equipment, unhygienic storage, and may be prone to micro leaks. Therefore, industrial oxygen cylinders need to be upgraded for medical use by undergoing a process of deep cleaning and disinfection, sealing micro leaks, replacing valves, and ensuring they are free of any contamination before their use for medical purposes. Given the acute shortage of oxygen on one hand, and the time and costs involved with this process on the other, it is likely that implementation of protocols for conversion of industrial oxygen cylinders to medical use at various levels was not adhered to thus enhancing the risks of mucormycosis. This is more so as there is currently no law that can make anyone accountable.
Study of mutation from DNA to biological evolution
Published in International Journal of Radiation Biology, 2019
Masako Bando, Tetsuhiro Kinugawa, Yuichiro Manabe, Miwako Masugi, Hiroo Nakajima, Kazuyo Suzuki, Yuichi Tsunoyama, Takahiro Wada, Hiroshi Toki
For organisms, oxygen was a very dangerous poison. Against such great catalysis, the living organisms that have survived were those who made effective utilization of such highly toxic waste thanks to the system of more efficient energy production, oxygen detoxification. As we have seen that ROS may be a major part of mutagen issue, let us make a trial to estimate quantitatively to see what kind of processes can connect micro- and macro-systems. At the moment, the answer is no more trusted but we dare to try, because such a quantification is challenging in spite of the current situation where there are no reliable estimates; no efficient direct measurements of ROS, few quantitative information on the mitochondrial production in vivo. Its macroscopic sketch on the relation between the oxygen consumption and the energy consumption (Flindt 2006).
Remdesivir, a remedy or a ripple in severe COVID-19?
Published in Expert Opinion on Investigational Drugs, 2020
SIMPLE enrolled subjects with COVID-19, radiographic evidence of pulmonary infiltrates, and (i) oxygen saturation of 94% or less while breathing ambient air or (ii) were receiving supplemental oxygen. Subjects were excluded if they were receiving mechanical ventilation and extracorporeal membrane oxygenation (ECMO). The enrolled subjects (397) had a mean age of ~61, and were predominantly white, and half had hypertension, and about a quarter had diabetes and/or hyperlipidemia. At the start, ~55% of subjects were at point 4 on the 7-point ordinal scale, and ~27% at point 3: DeathHospitalized, receiving invasive mechanical ventilation or ECMOHospitalized, receiving noninvasive ventilation or high-flow oxygen devicesHospitalized, requiring low-flow supplementary oxygenHospitalized, not requiring supplemental oxygen but receiving ongoing medical careHospitalized, requiring neither supplemental oxygen not ongoing medical careNot hospitalized
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