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Desaturating Patient with Long Bone Fractures
Published in Kajal Jain, Nidhi Bhatia, Acute Trauma Care in Developing Countries, 2023
Devendra Kumar Chouhan, Narendra Chouhan
Treatment objectives are to ensure good arterial oxygenation and to treat the underlying cause as soon as possible. High-flow oxygen is given to maintain the arterial oxygen tension in the normal range, and adequate maintenance of intravascular volume is important.
Physiology of the Neonate
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Airway resistance decreases from about 90 cmH2O/L/s in the first minute to about 25 cmH2O/L/min at the end of the first day of life. The resistance of nasal passages in the neonate is about 50% of the total airway resistance. Significant ventilation–perfusion mismatch occurs in the newborn, with a ventilation–perfusion ratio of 0.4 due to small airway closure. This results in a lower normal arterial oxygen tension of 50–70 mmHg (6.7–9.3 kPa) in the neonate. The central and peripheral chemoreceptors are well developed in the neonate. The ventilatory response to carbon dioxide is mature, with the CO2 response curve shifted to the left compared with the adult, so that ventilatory increases take place at a lower level of CO2 tension (Figure 74.7). The increase in ventilation is mainly achieved by an increased TV. Hypoxaemia causes a transient increase in ventilation for about 2 minutes in the immediate post-natal period, but a sustained response is seen by the 10th day after birth. The respiratory centre of the neonate is depressed by hypothermia.
Unusual Inherited Pulmonary Diseases Which Provide Clues to Pulmonary Physiology and Function
Published in Stephen D. Litwin, Genetic Determinants of Pulmonary Disease, 2020
Thomas Κ. C. King, Robert A. Norum
The factors which determine pulmonary hypertension in patients with scoliosis has been clarified in a recent study [188]. It seems that although the resting pulmonary artery pressure is inversely related to arterial oxygen tension, pulmonary hypertension is much less common at rest than during exercise. Further, the main determinant of the rate of increase of pulmonary artery pressure during exercise appears to be the magnitude of the vital capacity. These findings support the contention that lung size is an important factor in the prognosis of the patient.
Inclusion of resistance routines in a hypoxia training program does not interfere with prevention of acute mountain sickness
Published in The Physician and Sportsmedicine, 2021
Aritz Urdampilleta, Patxi León-Guereño, Julio Calleja-González, Enrique Roche, Juan Mielgo-Ayuso
Diagnosis and severity can be measured using the Lake Louise acute mountain sickness score, which allows identifying signals of AMS such as headache, anorexia/nausea, fatigue/weakness, and dizziness/light-headedness [5]. Headache is a mandatory symptom to diagnose the existence of AMS [5]. Nevertheless, more research is necessary to establish a severity ranking. In any case, if the experimental design needs this information, higher scores might suggest the existence of severe AMS [5]. In these cases, the climber must be evacuated to a lower altitude [2]. Determination of arterial oxygen saturation (SaO2) and arterial oxygen tension (PaO2) become lower in individuals affected by AMS compared to healthy controls. For this reason, a gradual plummet in SaO2 could be an alert parameter indicating a possible progression to pulmonary edema [7]. However, results from different studies are not conclusive and additional research has to be performed [2].
Physiological and oxidative stress responses to intermittent hypoxia training in Sprague Dawley rats
Published in Experimental Lung Research, 2020
Megha A. Nimje, Himadri Patir, Rajesh Kumar Tirpude, Prasanna K. Reddy, Bhuvnesh Kumar
The 2, 3-bisphosphoglycerate (2, 3-BPG) is a glycolytic intermediate and an important modifier of oxygen delivery by red blood cells during hypoxic condition. The enzyme bisphosphoglycerate mutase (BPGM) converts 1, 3-BPG to 2, 3-BPG.49 Increased in 2, 3-BPG levels, as seen in hypoxic condition,50,51 facilitate oxygen unloading to peripheral tissues. At high altitude where arterial oxygen tension is low, a low p50 (the arterial oxygen tension at which 50% of hemoglobin is saturated with oxygen) would load more oxygen onto hemoglobin in the lung with a higher concentration of 2, 3-BPG as a result of higher BPGM in the erythrocyte to bind to deoxyhemoglobin. Normally 2, 3-BPG is present at high concentrations (∼5 mM) in red blood cells and binds the deoxy form of hemoglobin to reduce its affinity for oxygen.52 In this study, there was a marked up regulated expression of BPGM in all the hypoxia exposed groups of animals. This could be due to an early adaptive mechanism to hypoxia, where BPGM makes more of the availability of 2, 3-BPG, which further binds with deoxy form of hemoglobin, thereby releasing oxygen molecules for tissue oxygenation as a part of cellular adaptation to tissue hypoxia. Similarly, previous studies showed that there exists a parallel relationship in between the increase in erythrocyte 2, 3-BPG level and the decrease in affinity of hemoglobin to bind to oxygen, thereby releasing more numbers of oxygen available to the tissues for its oxygenation,53 as a physiologic process to hypoxic adjustment.
Chronic interstitial lung diseases in children: diagnosis approaches
Published in Expert Review of Respiratory Medicine, 2018
Nadia Nathan, Laura Berdah, Keren Borensztajn, Annick Clement
Pulmonary function tests do not provide specific information. It may represent a useful investigation tool for both the diagnosis and the follow-up of ILD in older children and adolescents. Generally, in ILD, pulmonary function abnormalities reflect a restrictive ventilatory defect with reduced lung compliance and decreased lung volumes. Vital capacity (VC) is variably diminished; the decrease in total lung capacity (TLC) in general is relatively less than in VC. Functional residual capacity (FRC) is also reduced but relatively less than VC and TLC, and residual volume (RV) is generally preserved; thus, the ratios of FRC/TLC and RV/TLC are often increased. Airway involvement is observed only in a minority of patients. Lung diffusing capacity of carbon monoxide (DLCO) or transfer factor (TLCO) is often markedly reduced and may be abnormal before any radiological findings. Hypoxemia as defined by a reduced resting arterial oxygen saturation (SaO2) or a reduced resting arterial oxygen tension is often present. Hypercarbia occurs only late in the disease course. During exercise the above described dysfunctions become even more pronounced. Thus, gas exchange during exercise might be a more consistent and sensitive indicator of early disease [1,8].