2017 Sec 1 Green Book

Otolaryngology–Head and Neck Surgery 155(4)

A

point increase in AHI corresponds to a 1-point increase in the C-P score (95% confidence interval: 1.4-3.8, P \ .001). A simi- lar, 1.1% decrease in oxygen nadir corresponds to a 1-point increase in the C-P score (95% confidence interval: –1.7 to 2 0.5, P \ .001). These results indicate that the severity of ana- tomic obstruction in pediatric OSA, as defined with a systematic scoring system for DISE, correlates with both AHI and the lowest oxygen saturation on preprocedural PSG when known covariates are accounted for. Discussion The present data extend the previously published relation- ship between C-P score and PSG severity to a larger, multi- institutional prospective series of patients who underwent DISE. We hypothesized that the severity of anatomic obstruction would correlate with the severity of OSA as defined by the PSG. For this study, we chose to include all children who presented to our institutions with a PSG and met the criteria for undergoing DISE, regardless of age, severity of OSA, and medical complexity. We found a sta- tistically significant positive correlation between the C-P score and the AHI, as well as a statistically significant nega- tive correlation between the C-P score and the lowest oxygen saturation. Our analysis found a much stronger rela- tionship between C-P score and AHI than between C-P score and lowest oxygen saturation, as evidenced by the fact that a few patients with very low oxygen saturations had a significant influence over this correlation. These data pro- vide initial evidence supporting our hypothesis that the severity of anatomic obstruction in children with OSA, as measured with DISE, correlates with PSG parameters. Such data are important clinically, as DISE is becoming a widely utilized tool for the identification of airway obstruction in children with OSA. The evidence supporting DISE-directed surgery in the management of pediatric OSA is limited, and an organized approach toward studying this procedure, such as the one provided by the C-P scoring system, is critical to determining the proper role of DISE in the treatment of OSA. To our knowledge, this study represents the first to examine the relationship between anatomic obstruction in OSA, as measured by DISE, and preprocedural PSG para- meters in children. A number of studies have examined whether DISE findings are correlated with PSG severity in adult populations. Most recently, Dedhia and Weaver reviewed a case series of 65 adult patients who underwent DISE, and they scored the anatomic obstruction using the VOTE system (velum, oropharynx, tongue, epiglottis). 7 In this study, the authors failed to detect a significant associa- tion between the level of anatomic obstruction on DISE and the pre-DISE PSG parameters. Furthermore, this study failed to detect any significant associations between the severity of anatomic obstruction on DISE and Epworth Sleepiness Scale scores or quality of life as measured by the SNORE25 instrument. This study calls into question the external validity and clinical usefulness of DISE scoring systems for adult OSA patients.

120

100

80

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20

0

Apnea Hypopnea Index (event/hr)

0

2

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6

8

10

12

14

Chan-Parikh Score

B

100

90

80

70

60 O 2 Nadir (%)

50

40

0

2

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Chan-Parikh Score Figure 1. Correlation analysis: (A) apnea-hypopnea index and Chan-Parikh score ( r = 0.36, P \ .0001) and (B) O 2 nadir and Chan-Parikh score ( r = 2 0.26, P = .004).

demonstrated a positive moderate agreement ( r = 0.36, P \ .0001) between the AHI and the C-P score ( Figure 1A ). This analysis includes 5 patients with an AHI . 70; if these subjects are excluded from the study population, there is still a positive moderate agreement ( r = 0.32, P = .0004). Correlation analysis for AHI for patients who underwent DISE by the senior author demonstrated a positive moderate agreement (n = 58, r = 0.33, P = .01), as did correlation analysis for the remaining 7 surgeons (n = 69, r = 0.37, P = .002). Using the same methodology, we found a negative weak agreement between the lowest oxygen saturation and the C- P score ( r = 2 0.26, P = .004; Figure 1B ). Five patients were included in this analysis with a lowest oxygen satura- tion \ 65%, and excluding these subjects from the study population failed to demonstrate any agreement between C- P score and lowest oxygen saturation ( r = 0.16, P = .08). Correlation analysis for O 2 nadir for patients who underwent DISE by the senior author demonstrated a similar negative moderate agreement (n = 58, r = 2 0.3, P = .03); however, correlation analysis for the remaining 7 surgeons did not identify a significant correlation (n = 64, r = 2 0.2, P = .1). Multivariate linear regression analysis—controlling for age at endoscopy, presence of a syndrome, and history of adenotonsillectomy—demonstrated a statistically significant association between the C-P score and both preprocedural AHI and oxygen nadir. This analysis revealed that a 2.6-

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