The risk of serious adverse outcomes associated with hypoxaemia and hyperoxaemia in acute exacerbations of COPD

Abstract

In patients presenting via ambulance to the Emergency Department with AECOPD, serious adverse clinical outcomes are associated with both hypoxaemia and hyperoxaemia. These data provide further support for the principle of titrating supplemental oxygen therapy to target oxygen saturations.

Chronic obstructive pulmonary disease pathways as a tool to improve appropriateness in Internal Medicine Departments

“…Should be favored the nebulisers by compressed air or electric; should be avoided, instead, the use of oxygen as propellant gas, because, as it will be explained later, in the moderate or severe exacerbations of COPD, the high-flow oxygen necessary for the nebulization of the drug (8-10 L/min), can cause worsening of hypercapnia. [25][26][27] In common clinical practice, administration of short-acting bronchodilators every 5-6 h is easily accomplished during daylight hours, while it is more difficult during the night. And it is during the night that the physiological circadian oscillation of bronchial tone leads to increased bronchoconstriction, with worsening dyspnea 28,29 Therefore, although there are no controlled clinical trials on this procedure, it is rational to associate the short-acting bronchodilator therapy in repeated doses during daylight hours (at 8 am, 2 pm, 8 pm or 7 am, 1 pm, 7 pm) with a single dose in the evening (at 11 pm) of an inhaled bronchodilator long-acting, associated or not with inhaled corticosteroid, through the use of MDI with spacer.…”

“…Oxygen is a drug and, therefore, it is necessary to pay attention to its prescription, specifying the system of administration and dose, i.e., the fraction of inspired oxygen (FiO 2 ); the correct determination of FiO 2 is essential to avoid the disadvantages of overdosing or underdosing. 40 The dosage, which varies from case to case, should be adjusted based on arterial oxygen saturation to be achieved in the specific type of patient. While in hypoxemic-normocapnic patients the goal of oxygen therapy is a saturation of 94-98%, in hypoxemic and hypercapnic patients or at risk of hypercapnia, as the patients with COPD are often, the target saturation should be much lower, around 88-92%.…”

“…However, they have important limitations: reduction in oxygena- [ Chronic obstructive pulmonary disease pathways The need to ensure a controlled oxygen therapy often clashes with the mode of execution of the aerosol therapy to administer the inhaled bronchodilators. [25][26][27] In most wards, as well as in ambulances, the aerosol is carried out using oxygen at high flows as nebulizing gas (with FiO 2 up to 60%). This, as mentioned above, can favor the hypercapnic acidosis, which often appears quite early, even within 15 minutes from the beginning of the high flow of O 2 .…”

Concerns regarding the design of the bedside monitoring chart for use with the NEWS (National Early Warning System)

“…[1][2][3][4] The proportion of hospital patients at risk of hypercapnic respiratory failure is not known but estimates may be made as follows:…”

“…The British Thoracic Society Emergency Oxygen Guideline (endorsed by the Royal College of Physicians) recommends a target saturation range of 88-92% for patients at risk of T2RF because the use of high concentration oxygen therapy may double the risk of death, mechanical ventilation or hypercapnic respiratory failure. [1][2][3][4] The NEWS observation chart may encourage clinicians to aim for an oxygen saturation of ≥96% for patients at risk of T2RF.…”