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In case of hypoxemia, the oxygen content is often still in the lower normal range, so that there is no hypoxia in the tissue. If the hypoxia-threshold is reached in the tissue in hypoxic, anemic and also cardiac-related hypoxemia, identical counterregulations occur in the cell metabolism, regardless of the cause of hypoxemia. In clinical practice, this pathophysiologic fact is sometimes ignored, although depending on the cause of hypoxemia, assessment and therapy vary widely. While restrictive and generally accepted rules are specified in the transfusion guidelines for anemic hypoxemia, in the case of hypoxic hypoxia, the indication for invasive ventilation is made very early. The clinical assessment and indication are limited to the parameters oxygen saturation, oxygen partial pressure and oxygenation index. During the corona pandemic, misinterpretations of pathophysiology have become evident and may have led to unnecessary intubations. However, there is no evidence for the treatment of hypoxic hypoxia with ventilation. This review addresses the pathophysiology of the different types of hypoxia focusing on the problems associated with intubation and ventilation in the intensive care unit., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Inhalation of bronchodilators and corticosteroids is the mainstay treatment for patients with obstructive lung diseases. Many dry powder inhaler devices and drug combinations are now available, and competing promotional claims can confuse both prescribers and patients. The appropriate dose of a given drug may be different for a pressurized metered dose inhaler (pMDI) and a dry powder inhaler (DPI). DPIs create aerosols by drawing air through an aliquot of dry powder. The powder contains either micronized (< 5 micro m in diameter) drug particles bound into loose aggregates, or micronized drug particles that are loosely bound to large (> 30 micro m in diameter) lactose or glucose particles. Usually, the drug particles are bound to carrier particles and are stripped form the carrier particles by the energy provided by the patientacute;s inhalation. The release of respirable particles of the drug requires inspiration at relatively high flow rates (30 - 120 L/min). Other important factors influencing aerosol generation and lung deposition are device design (resistance to airflow) and environmental conditions (humidity, temperature). Preferably, patients should employ only one type of aerosol-generating device for inhalation therapy. The technique of use varies among devices, and repeated instruction is highly advisable, to ensure that the patient uses the device appropriately. At present, DPIs are recommended for prophylactic and maintenance therapy in patients with asthma and chronic obstructive pulmonary disease, but not for patients with acute severe bronchoconstriction or children less than 5 years of age.