Determination of oxygen status in human blood
John Edward Boland, David W. M. Muller in Interventional Cardiology and Cardiac Catheterisation, 2019
Oxygen concentration refers to the total amount of oxygen contained within a unit volume of blood and is commonly expressed as mmol/L, Vol% or mls oxygen per dL of whole blood. Oxygen is carried in blood in two states: Dissolved oxygen in blood: The amount of dissolved oxygen in the blood depends upon the pO2(B) (it also varies slightly with ctHb) and is 0.003 mL/dL blood/mmHg pO2(B) (concentrational solubility coefficient for oxygen in blood, called α).2,3Oxygen bound to haemoglobin, of which oxygen saturation [SO2(B)] is the percentage that oxygen-bound haemoglobin constitutes of the total haemoglobin capable of carrying oxygen.4,5 Oxygen bound to haemoglobin constitutes approximately 99% of the oxygen content of blood. Ideally, when fully saturated with oxygen, each gram of normal haemoglobin holds 1.39 mL of oxygen. However, due to the presence of dyshaemoglobins, the in vivo value for fully saturated haemoglobin is 1.36 mL of oxygen/gm haemoglobin.
Cervical spine fractures
Charles M Court-Brown, Margaret M McQueen, Marc F Swiontkowski, David Ring, Susan M Friedman, Andrew D Duckworth in Musculoskeletal Trauma in the Elderly, 2016
The acute management of spinal cord injury in geriatric patients is no different than in younger patients. After evaluation, the goals are to protect against further injury, reduce fracture dislocations and provide long-term stability. Prevention of further spinal cord injury is achieved by accurate diagnosis, care and handling. Specifically, the neck and head should be immobilized with a collar, and proper lifting and rolling techniques should be utilized. Shock should be aggressively treated. In a spinal cord injury patient hypotension may be from neurogenic shock due to the loss of vascular tone and this form of shock responds best to vasopressors rather than fluids or blood products. It should be rapidly corrected and mean arterial blood pressure maintained at 85 mm Hg and continued for 5 days. Supplemental oxygen to maintain an oxygen saturation of at least 90% is essential. Neuroprotective agents, such as methylprednisolone, should be used with caution in geriatric patients. The use of methylprednisolone in younger patients is controversial at best and recent guidelines recommend against its routine use due to the lack of proven efficacy and the variety of complications that are seen including pneumonia, sepsis, gastrointestinal hemorrhage and death.39 These complications are more common in elderly patients.39
The patient with acute cardiovascular problems
Peate Ian, Dutton Helen in Acute Nursing Care, 2020
Acutely, patients presenting in AF required a detailed assessment to evaluate clinical status and deterioration risk. Triggering factors such as sepsis, anaemia, pulmonary embolism, electrolyte imbalance or hypoxaemia should be considered and addressed. Supplemental oxygenation may be necessary to maintain target oxygen saturation, treating hypoxaemia. Serum electrolytes should be replaced to keep within normal range, as they play a role in cardiac rhythm stability. Many patients present in AF with a tachycardia; NICE (2014) and ESC (2016b) have developed guidance, suggesting two essential treatment approaches: Rate control.Rhythm control.
Alive attenuated Salmonella as a cargo shuttle for smart carrying of gold nanoparticles to tumour hypoxic regions
Published in Journal of Drug Targeting, 2019
Amirhosein Kefayat, Fatemeh Ghahremani, Hasan Motaghi, Soodabeh Rostami, Masoud A. Mehrgardi
Many therapeutic approaches including surgery, chemotherapy and radiation therapy have been used for cancer treatment [3]. Radiation therapy or radiotherapy (RT) is a highly effective modality for curative and palliative purposes. More than fifty per cent of cancer patients benefit from RT during their disease [4]. RT therapeutic mechanism is to deposit destructive energies on cancer cells by high energy radiation beams [5]. However, different parts of tumour exhibit diverse responses to RT due to the tumour’s microenvironment heterogeneity [6,7]. One of these heterogeneity factors is oxygen. According to oxygen concentration, tumour microenvironment is highly dynamic and heterogeneous [8]. Many parts of the tumour are under the hypoxic condition which is a tumour-specific phenomenon [9]. Normal tissues have an approximately stable oxygen concentration at physiological conditions. While the oxygen concentration differs at various organs over a range of 10 to 80 torrs [10], the oxygen pressure at many tumours sites is less than 5 torrs which are known as hypoxia [11]. Tumour hypoxia can be attributed to insufficient densities and irregular orientations of microvessels as oxygen suppliers. Also, the high metabolic activity of cancer cells can cause a significant imbalance between oxygen to convey and usage [12,13].
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
Which is more important: the number or duration of respiratory events to determine the severity of obstructive sleep apnea?
Published in The Aging Male, 2020
Dilber Yılmaz Durmaz, Aygül Güneş
Polysomnography (PSG) is the gold standard for the diagnosis of obstructive sleep apnea (OSA), and the apnea–hypopnea index (AHI) has been used as the main parameter to classify the severity of the disease. The AHI is the number of apneas and hypopneas recorded during the PSG per hour of sleep. Based on the AHI, the severity of OSA is classified as: normal, AHI < 5; mild, 5 ≤ AHI < 15; moderate, 15 ≤ AHI < 30; and severe, AHI ≥ 30 events per hour. The duration of respiratory events in patients with OSA can vary widely, from ten seconds to more than two minutes. These partial and total cessations of breathing can lead to a drop in the oxygen saturation. Oxygen desaturation index (ODI), representing the average number of desaturation events per hour of sleep, is another parameter currently considered in the diagnostics of sleep-disordered breathing [1,2]. At present, AHI remains the major and primary diagnostic and classification parameter for OSA, however, does not contain information on the duration and morphology of the breathing cessations and desaturations. Obviously, within the same severity of OSA, longer apnea–hypopnea duration and deeper desaturation may have different consequences than shorter and shallower ones. This raises the question of whether AHI is the best parameter to evaluate the overall severity of OSA. Therefore, additional new advanced parameters are necessary that more accurately reflect demographic parameters, blood oxygenation, and polysomnographic sleep parameters in patients with OSA.