2017 Sec 1 Green Book

Dahl et al

DISE scoring systems have not been proven to correlate well with sleep apnea parameters in adults. 7 It is still unknown if DISE accurately identifies sites of obstruction in children with polysomnogram (PSG)–diagnosed OSA. In 2014, we introduced and validated a new scoring system for DISE (Chan-Parikh [C-P] score) in children with OSA to identify the location and severity of obstruction. 8 This study builds on that work by presenting new data on patients undergoing DISE to determine if standardized scoring correlates with PSG parameters. We hypothesized that the C-P DISE score would correlate with PSG findings— specifically, apnea-hypopnea index (AHI) and oxygen nadir, broad indicators of OSA severity. As a secondary objective, we sought to determine if age at the time of DISE, presence of a syndrome, or history of adenotonsillectomy affect this relationship. Methods Institutional Review Board approval was obtained from the 2 participating institutions: Seattle Children’s Hospital (SCH) and the University of California–San Francisco (UCSF). At both institutions, all patients undergoing DISE are scored prospectively via the C-P score, and the findings are recorded in a database. These databases contain basic patient demographic information (date of birth, date of pro- cedure, comorbidities), limited PSG parameters (AHI, lowest O 2 saturation) if the patient underwent preoperative PSG, and the C-P score. Records of all patients in these databases were screened between January 1, 2011, and December 31, 2014, to obtain past medical and surgical his- tory. All patients who underwent PSG prior to DISE were included in the study; there was no restriction on how far in advance of DISE the PSG was performed. The decision to perform DISE was based on clinical evaluation by the attending surgeon. DISEs were typically performed on chil- dren with small or absent tonsils or with clinical suspicion for multilevel airway obstruction. Children who did not have preoperative PSG were excluded from the study; PSG was not always obtained prior to DISE, based on clinical judgment, cost, and family decision making. Subjects underwent PSG at an accredited sleep laboratory as part of clinically indicated care, with results interpreted by board-certified pediatric sleep medicine physicians. PSGs were scored in accordance with the American Academy of Sleep Medicine parameters. 9 AHI and lowest recorded oxygen saturation were noted from the preproce- dural PSG. At both tertiary care facilities, sleep endoscopy is carried out in standardized fashion, with all reports being categor- ized per the C-P scoring system, which has been published and validated. 8 The anesthetic technique for all DISE uti- lized sevoflurane and propofol per institutional protocols. The C-P score is based on 5 anatomic locations, with each site graded on a 4-point scale according to severity of obstruction. Sleep endoscopy scores were noted at the time of surgery by the surgeon responsible for each case.

After all cases had been identified, chart review was per- formed to acquire the demographic characteristics of the participants, including age at time of sleep endoscopy, sur- gical history, and presence of concomitant syndromal or genetic disorder (eg, Trisomy 21). Univariate analyses were performed to obtain descriptive statistics. Means were calcu- lated for continuous variables, such as PSG and sleep endo- scopy scores, along with average age at time of DISE. Proportions were calculated for binary variables, such as the presence of a syndrome. Mean AHI and lowest oxygen saturation values for PSGs performed at UCSF and SCH were compared with Student’s t test to ensure consistency between studies performed at the separate institutions. Spearman’s correlation coefficients (2-tailed) were then calculated to determine the degree of linear correlation between C-P score and each PSG result: AHI and oxygen nadir. To determine if there was significant variability in DISE results among the 8 attending surgeons, Spearman’s correlation coefficients were also calculated for AHI and lowest oxygen saturation for patients who underwent DISE by the senior author (S.R.P.; n = 58) and the other 7 sur- geons (n = 69). Two separate multivariable linear regression models were then created, controlling for syndrome diagno- sis, history of adenotonsillectomy, and age at time of sleep endoscopy. AHI and oxygen nadir were used as the depen- dent variables in these models, while C-P score was the independent variable. For all tests, P \ .05 was considered statistically significant. Stata 13.1 (Stata Inc, College Station, Texas) statistical software was used for all analyses. Results A total of 127 children met inclusion criteria for the study. The demographic composition of this patient population is outlined in Table 1 . The mean AHI value for PSGs per- formed at UCSF was 11.7 6 12.8 ( 6 SD), while at SCH the mean AHI value was 14.1 6 20.9. There was no statisti- cally significant difference in the mean AHI values between the centers ( P = .6). Mean lowest oxygen saturations were also not significantly different between patients at the 2 institutions: mean O 2 nadir at UCSF was 82% 6 9.5%, compared with 86% 6 9.4% at SCH ( P = .1). The scatter- plots represented in Figure 1 demonstrate AHI and oxygen nadir as a function of C-P score. Correlation analysis

Table 1. Demographic Characteristics of the Study Population. a

Subjects

127

6.55 6 5.34

Age at time of DISE, y

Syndromal or genetic disorder Previous adenotonsillectomy

56 (44)

21 (16.5)

13.6 6 19.6 85.4 6 9.4

AHI, events/h

O 2

nadir, % (O 2

saturation)

5.9 6 2.7

Chan-Parikh score

Abbreviations: AHI, apnea-hypopnea index; DISE, drug-induced sleep endoscopy. a Values presented as n (%) or mean 6 SD.

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