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A. Dharmasena, D. Pilkington, L. Bradshaw, K. L. Smyth; Effectiveness of the Practice of Oxygenation of Patients Undergoing Modern Cataract Surgery Under Local Anaesthesia. Invest. Ophthalmol. Vis. Sci. 2008;49(13):385. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To study the variation of Fraction of inspired Oxygen (FiO2) and Instantaneous Measurement Carbon dioxide (IMCO2) under the drape and blood oxygen saturation (SpO2) during cataract surgery with and without oxygen supplementation and to understand the practice of oxygen supplementation during modern cataract surgery under local anaesthesia in the UK and Ireland .
200 patients without significant cardio-respiratory co-morbidities were prospectively randomized into 2 groups. The first group received 5 l/min oxygen via bar into the ambient air under the drape and the second group received no oxygen. 3 readings of FiO2,IMCO2 and SpO2 were recorded at the begining, middle and end of surgery. 50 patients from each group were randomly selected for statistical analysis. The variation of FiO2, IMCO2 and SpO2 during surgery was analysed in each group and two groups were compared using Wilcoxon Signed Rank Test.A postal questionnaire was sent to the Theatre Managers in all the ophthalmic surgical units in the UK and Ireland to understand their practice of oxygen supplementation during modern cataract surgery under local anaesthesia.
Patients who received no oxygen showed no significant variation between the 3 readings of FiO2, IMCO2 or SpO2 taken at the begining, middle and end of surgery. Group which received oxygen showed a statistically significant fluctuation of all 3 parameters.There was no significant difference of IMCO2 under the drape between two groups throughout the whole procedure. As expected, FiO2 in the first group was higher than the second group (p-value: <0.0001). The oxygen saturation between the two groups both at the beginning and the end of surgery were statistically insignificant but readings taken at the middle showed a significant difference (p-value: 0.009).The response rate of appropriately completed questionnaires was 42.4%.Average number of cataract surgeries performed by a single unit was 2222. 72% units administered oxygen to all, 24% to some and 4% to none of their patients. 11% of units used an air oxygen mixture and 1% used only air. The most popular mode of delivery of oxygen was the bar under the drape (81%). The volume of oxygen delivered ranged from 2 l/min to 10 l/min, and 65% delivered oxygen at a rate of ≥4 l/min.
The benefit of free flowing oxygen under the drape during modern cataract surgery in otherwise healthy subjects is not clear. Majority of ophthalmic surgical units in the UK routinely administer oxygen using the bar under the drape to all their patients during cataract surgery at a rate ≥ 4 l/min.
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