Audit of Prehospital Oxygen Use in Acute COPD Exacerbation
Audit of Prehospital Oxygen Use in Acute COPD Exacerbation
There were 119 admissions in 2005 and 190 in 2010 eligible for inclusion in the analysis (figure 2). The age and physiological measurements, taken on ambulance arrival, were similar in 2005 and 2010, and are shown in Table 1. The proportions of patients with home nebuliser use, home oxygen prescription, long-term oral steroids, a history of assisted ventilation and previous type II respiratory failure were higher in the 2005 group.
(Enlarge Image)
Figure 2.
Patient inclusion/exclusion pathway. COPD, Chronic obstructive pulmonary disease; WRH, Wellington Regional Hospital.
There were 108 and 182 admissions in 2005 and 2010, respectively, that were able to be categorised in the HIGH, NEB and LOW oxygen treatment groups for analysis. Nebulised medication was administered to just over half of the patients in 2005 and 2010. The mean number of nebulisers administered to patients given at least one nebulisation was 1.6 in 2005 and 1.7 in 2010. The proportions of patients in the three oxygen groups are shown in Table 2. These were significantly different between 2005 and 2010; χ=26.8, 2 df, p<0.001. There was a marked reduction in the proportion in the HIGH category, falling from 75% to 44%.
The unadjusted OR for risk for assisted ventilation for 2010 versus 2005 was 0.71 (0.52 to 0.98), p=0.003. The association between the year for 2010 versus 2005 and need for assisted ventilation was weaker and not statistically significant after adjustment for a past history of type II respiratory failure and oxygen administration type 0.76 (0.53 to 1.09), p=0.14. A history of type II respiratory failure significantly influenced the risk of assisted ventilation (p<0.001) in the multivariate analysis, however oxygen administration type did not, (HIGH vs LOW, p=0.69 and NEB vs LOW, p=0.54). The unadjusted OR for risk for death for 2010 versus 2005 was 1.10 (95% CI 0.31 to 3.84), p=0.88.
There were 84 and 147 admissions in 2005 and 2010, respectively, that had more than one oxygen saturation documented in their ambulance record and were able to be categorised into a HIGH, NEB or LOW group. The final oxygen saturations recorded by the ambulance staff are shown in Table 3. There was a statistically significant difference in median oxygen saturations, 98% (IQR 95 to 99) in 2005 and 96% (IQR 94 to 98) in 2010, difference 1.5% (95% CI 1.0 to 2.0), p<0.001. There were only 1/84 and 4/147 patients with final oxygen saturations less than the lower limit of the recommended oxygen saturation target range (88 to 92%) in 2005 and 2010, respectively. There were no patients with an oxygen saturation ≤88% in the LOW oxygen group in either year. The majority of patients had saturations over 92%, regardless of year or oxygen regimen. The proportion of patients with an oxygen saturation ≥97% was 58/84 (69%) in 2005 and 69/147 (47%) in 2010. In both years the majority of patients in the NEB group had a final oxygen saturation ≥97% (Table 3). Arterial blood gas samples were taken within the first 30 min of arrival to the emergency department in 9% (10/108) and 5% (9/182) of patients in 2005 and 2010, respectively.
Results
There were 119 admissions in 2005 and 190 in 2010 eligible for inclusion in the analysis (figure 2). The age and physiological measurements, taken on ambulance arrival, were similar in 2005 and 2010, and are shown in Table 1. The proportions of patients with home nebuliser use, home oxygen prescription, long-term oral steroids, a history of assisted ventilation and previous type II respiratory failure were higher in the 2005 group.
(Enlarge Image)
Figure 2.
Patient inclusion/exclusion pathway. COPD, Chronic obstructive pulmonary disease; WRH, Wellington Regional Hospital.
There were 108 and 182 admissions in 2005 and 2010, respectively, that were able to be categorised in the HIGH, NEB and LOW oxygen treatment groups for analysis. Nebulised medication was administered to just over half of the patients in 2005 and 2010. The mean number of nebulisers administered to patients given at least one nebulisation was 1.6 in 2005 and 1.7 in 2010. The proportions of patients in the three oxygen groups are shown in Table 2. These were significantly different between 2005 and 2010; χ=26.8, 2 df, p<0.001. There was a marked reduction in the proportion in the HIGH category, falling from 75% to 44%.
The unadjusted OR for risk for assisted ventilation for 2010 versus 2005 was 0.71 (0.52 to 0.98), p=0.003. The association between the year for 2010 versus 2005 and need for assisted ventilation was weaker and not statistically significant after adjustment for a past history of type II respiratory failure and oxygen administration type 0.76 (0.53 to 1.09), p=0.14. A history of type II respiratory failure significantly influenced the risk of assisted ventilation (p<0.001) in the multivariate analysis, however oxygen administration type did not, (HIGH vs LOW, p=0.69 and NEB vs LOW, p=0.54). The unadjusted OR for risk for death for 2010 versus 2005 was 1.10 (95% CI 0.31 to 3.84), p=0.88.
There were 84 and 147 admissions in 2005 and 2010, respectively, that had more than one oxygen saturation documented in their ambulance record and were able to be categorised into a HIGH, NEB or LOW group. The final oxygen saturations recorded by the ambulance staff are shown in Table 3. There was a statistically significant difference in median oxygen saturations, 98% (IQR 95 to 99) in 2005 and 96% (IQR 94 to 98) in 2010, difference 1.5% (95% CI 1.0 to 2.0), p<0.001. There were only 1/84 and 4/147 patients with final oxygen saturations less than the lower limit of the recommended oxygen saturation target range (88 to 92%) in 2005 and 2010, respectively. There were no patients with an oxygen saturation ≤88% in the LOW oxygen group in either year. The majority of patients had saturations over 92%, regardless of year or oxygen regimen. The proportion of patients with an oxygen saturation ≥97% was 58/84 (69%) in 2005 and 69/147 (47%) in 2010. In both years the majority of patients in the NEB group had a final oxygen saturation ≥97% (Table 3). Arterial blood gas samples were taken within the first 30 min of arrival to the emergency department in 9% (10/108) and 5% (9/182) of patients in 2005 and 2010, respectively.
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