Randomised controlled trial of high concentration versus titrated oxygen therapy in severe exacerbations of asthma

Abstract

BackgroundThe effect on PaCO 2 of high concentration oxygen therapy when administered to patients with severe exacerbations of asthma is uncertain. Methods 106 patients with severe exacerbations of asthma presenting to the Emergency Department were randomised to high concentration oxygen (8 l/min via medium concentration mask) or titrated oxygen (to achieve oxygen saturations between 93% and 95%) for 60 min. Patients with chronic obstructive pulmonary disease or disorders associated with hypercapnic respiratory failure were excluded. The transcutaneous partial pressure of carbon dioxide (PtCO 2 ) was measured at 0, 20, 40 and 60 min. The primary outcome variable was the proportion of patients with a rise in PtCO 2 $4 mm Hg at 60 min. Results The proportion of patients with a rise in PtCO 2 $4 mm Hg at 60 min was significantly higher in the high concentration oxygen group, 22/50 (44%) vs 10/53 (19%), RR 2.3 (95% CI 1.2 to 4.4, p<0.006). The high concentration group had a higher proportion of patients with a rise in PtCO 2 $8 mm Hg, 11/50 (22%) vs 3/53 (6%), RR 3.9 (95% CI 1.2 to 13

To Give or Not To Give - Is that the Question?: The Changing Face of Emergency Oxygen Therapy

“…The importance of titrating oxygen to achieve target saturation ranges has become increasingly apparent, with a number of randomised controlled trials indicating that failure to do so, instead over-oxygenating patients presenting with respiratory conditions, can lead to life threatening, if not fatal, respiratory acidosis [15,[29][30][31].…”

“…For example a New Zealand study recorded the effect of high concentration oxygen therapy on asthma patients in the emergency department [29]. Through transcutaneous monitoring of CO 2 (PtCO 2 ) blood levels, the researchers set out to estimate the proportion of patients with a clinically significant rise in PtCO 2 .…”

Mortality in Asthma-Chronic Obstructive Pulmonary Disease Overlap in the United States

“…In severe exacerbations, controlled low flow oxygen therapy using pulse oximetry to maintain saturation at 93-95% is associated with better physiological outcomes than with high flow 100% oxygen therapy [349][350][351] (Evidence B). However, oxygen therapy should not be withheld if pulse oximetry is not available (Evidence D).…”

“…Controlled or titrated oxygen therapy gives better clinical outcomes than high-flow 100% oxygen therapy [349][350][351] (Evidence B). Oxygen should not be withheld if oximetry is not available, but the patient should be monitored for deterioration, somnolence or fatigue.…”

Difficult decisions: An interpretative phenomenological analysis study of healthcare professionals’ perceptions of oxygen therapy in palliative care

“…[1,2] Symptom control is a central tenet of palliative care, yet the use of oxygen to palliate dyspnoea is an area of uncertainty, debate and controversy. [3] Principally this is because, despite widespread use of oxygen, a growing tide of evidence [4][5][6][7][8] suggests that, unless given to correct hypoxaemia (low blood oxygen), it offers little, or no, benefit to patients. Additionally, drawbacks are apparent, including physical, psychological, emotional and social discomfort.…”