Evaluation of inpatient oxygen therapy in hypercapnic chronic obstructive pulmonary disease

Abstract

Background: High concentration oxygen therapy in hypercapnic chronic obstructive pulmonary disease (COPD) is associated with increased mortality. In ward-based patients with acute exacerbation of COPD and hypercapnia, this study examines oxygen prescription and the association between high concentration oxygen therapy and adverse outcome. Aims:To investigate the association between over-oxygenation and in-hospital adverse events.Methods: Inpatients with acute exacerbation of hypercapnic COPD at a tertiary Australian hospital over a 1-year period were retrospectively identified. Oxygen prescription and therapy was determined based on chart review. Over-oxygenation was defined as ≥10% of nursing chart observations recording oxygen delivery with oxygen saturation above 92%. A composite adverse outcome was defined as medical emergency team response, recommencement of non-invasive ventilation or death. The association between over-oxygenation and adverse outcome was assessed using survival analysis and conditional logistic regression modelling. Results:The study cohort comprised 106 unique patients and 157 admissions. Oxygen prescription was recorded in 132 (84%) and over-oxygenation occurred in 97 (62%) admissions. Over-oxygenation was higher in non-respiratory ward admissions (76% vs 57%, P = 0.03) and those without any form of oxygen prescription (84% vs 58%, P = 0.01). During follow up, 23 (22%) patients experienced an adverse event. Cox proportional hazards modelling found weak evidence for increased risk of an adverse event in over-oxygenated patients (hazard ratio 2.5; 95% confidence interval 0.8-7.3, P = 0.10). Conditional logistic regression, after matching on age, Charlson comorbidity category and length of follow up, found a similar estimate of association (hazard ratio 2.6; 95% confidence interval 0.8-8.7, P = 0.12).Conclusions: Over-oxygenation to hypercapnic COPD inpatients is common and rates of oxygen prescription are suboptimal. We found weak evidence of association between over-oxygenation and adverse events, likely due to low statistical power. Larger prospective studies are needed.

Over‐oxygenation in the acute hospital setting: an implementation failure in need of an implementation science solution

“…However, these events may have arisen due to any of several causes, of which overoxygenation was only one possibility. 14 Anderson et al report findings from a similar study 13 focussed on inpatients with COPD and hypercapnia (PaCO 2 ≥45 mmHg) on admission. Of 1160 COPD admissions, hypercapnia was present on admission in 16%, with a final sample of 157 admissions (106 patients) included.…”

“…3 In this issue of the Internal Medicine Journal, three articles consider these issues further. [13][14][15] Deshpande et al report suboptimal adherence to acute oxygen use guidelines in a study of hospitalised patients with COPD. 14 In this single-site, retrospective chart review, 557 admissions for 457 patients were included, with patients predominantly admitted for respiratory or cardiac conditions.…”

“…The authors identified that oxygen prescriptions were well-documented in medical records (82%) but poorly recorded on prescription charts (13%). 13 Over-oxygenation occurred in almost two-thirds of admissions and was significantly more likely to occur in patients admitted to non-respiratory wards or in the absence of an oxygen prescription. Adverse events were more prevalent in this study (22% of patients); however, while there was a trend towards an association between over-oxygenation and adverse events, this was not statistically significant.…”

“…Adverse events were more prevalent in this study (22% of patients); however, while there was a trend towards an association between over-oxygenation and adverse events, this was not statistically significant. 13 The third article in this issue of the Journal is by Nguyen et al and reports the findings from a small, single-site study investigating the effectiveness of an oxygen therapy education programme for nursing and junior medical staff on respiratory, oncology and surgical wards. 15 The programme comprised a 30-min education session regarding guideline recommendations for oxygen use in respiratory failure.…”

“…16 While all three of these studies were relatively small, with two being retrospective medical audits, nevertheless, the fundamental message remains that acute oxygen therapy is still not well managed in hospitals with low adherence to guideline recommendations and patients who receive oxygen therapy are often over-oxygenated. [13][14][15] Importantly, all three studies identified wide variability in acute oxygen management practices, with opportunities for improvement throughout the hospital environments. While patients cared for on respiratory wards received more guideline concordant oxygen therapy, even in those respiratory areas (where healthcare staff are more experienced and specifically trained to manage oxygen therapy), there were suboptimal oxygen management practices.…”