3.4 Upper airway surgery
The DS cohort was divided into those with a past history of upper airway surgery, either adenotonsillectomy or tonsillectomy with subsequent residual OSA requiring NIV and those that had no past upper airway surgical history (Figure 3).
There were no significant differences observed in the usage parameters of percentage of days used and of days used >4hrs between those who had past surgical intervention relative to those without. Both groups showed >4hrs of use in over 50% of nights, 52.44 ± 5.17% in the surgical group and 59.35 ± 3.53% in those without. Conversely, the non-surgical group showed significantly greater average use per night of 5.31 ± 0.32hours/night compared to 4.14 ± 0.48 hours/night in the surgical cohort, p= 0.035.
No statistical significance was observed in AHI measurements between the surgical and non-surgical cohorts, 6.23 ± 0.99 and 5.41 ± 0.52, respectively.
Increased leakage was observed within the surgical cohort. Mean system leakage of 47.53L/min was recorded in the surgical group compared 36.74L/min in the non-surgical group (p=0.001). Those within the surgical cohort also displayed significantly greater time at excess leak (27.63 ± 4.07%) compared to their surgical naive comparators (15.62 ± 1.90%), p=0.003.