2017-18 HSC Section 3 Green Book

j o u r n a l o f s u r g i c a l r e s e a r c h o c t o b e r 2 0 1 6 ( 2 0 5 ) 4 9 0 e 4 9 8

Table 4 e Significance of surgical emphysema on CTA in identifying airway injuries. CT findings Patients with confirmed airway injuries

Patient without airway injury

Any airway injury

Larynx

Cervical trachea

Thoracic trachea

CTA suggestive of injury total

10

4

3

3

153

Deep cervical emphysema

10

4

3

3

153

Mediastinal emphysema

9

3

3

3

80

CTA not suggestive of injury

1

0

One (CTA only done 10 d postinjury)

0

219 (35 of these CTA could not be reviewed for emphysema)

Total

11

4

4

3

372

Sensitivity

91.0% (10/[10 þ 1])

100% (4/4)

75% (3/[3 þ 1])

100% (3/3)

Specificity

58.9% (219/[219 þ 153])

Positive predictive value (PPV) Negative predictive value (NPV)

6.1% (10/[10 þ 153])

2.5% (4/[4 þ 153])

1.9% (3/[3 þ 153])

1.9% (3/[3 þ 153])

99.5% (219/[219 þ 1])

CTA ¼ computed tomography angiography.

The other seven had extensive bilateral deep cervical emphy- semaandmediastinal emphysema. For sevenof thesepatients, a DTI was excluded by a normal WS-swallow and for one pa- tient with an equivocal WS-swallow examination, a subse- quent flexible upper endoscopy excluded DTI. All of the 11 patients with confirmed airway injuries had positive clinical findings suggestive of ADTI. Table 4 demonstrates this data.

these patients had a confirmed ADTI. Table 5 demonstrates this data.

Significance of surgical emphysema on CTA in patients with confirmed ADTI correlated for pneumothoraces

A total of 281 patients of 383 who underwent a CTA did not have a pneumothorax, and 32 of these had confirmed ADTI. When excluding patients with pneumothoraces, the sensi- tivity, specificity, PPV, and NPV of deep surgical emphysema for the diagnosis of any ADTI were therefore 94.1% (32/ [32 þ 2]), 71.9% (179/[179 þ 70]), 30% (30/[30 þ 70]), and 98.9% (179/[179 þ 2]). The sensitivity and NPV were, however, 100%,

Significance of surgical emphysema on CTA in patients with pneumothoraces

A total of 102 patients had a pneumothoraces and 63 of these patients had deep surgical emphysema on CTA. Only 14 of

Table 5 e Significance of surgical emphysema on CTA in identifying pneumothoraces. CT findings Patients with confirmed pneumothorax

Patient without pneumothorax

CTA suggestive of injury total

63 (but 14 of these had confirmed ADTI)

100 (but 32 of these had confirmed ADTI)

Deep cervical emphysema

61

99

Mediastinal emphysema

44

45

CTA not suggestive of injury

39 (seven of these CTA could not be reviewed for emphysema)

181 (28 of these CTA could not be reviewed for emphysema)

Total

102

281

Sensitivity (sensitivity correlated for ADTI)

61.8% (63/[63 þ 39]); 55.7% ([63-14]/[63-14 þ 39])

Specificity

64.4% (181/[181 þ 100]); 72.7% (181/[181 þ 100-32])

Positive predictive value (PPV; PPV correlated for ADTI)

38.7% (63/[63 þ 100]); 41.9% (63-14/[63-14 þ 100-32])

Negative predictive value (NPV)

82.3% (181/[181 þ 39])

ADTI ¼ aerodigestive tract injury; CTA ¼ computed tomography angiography.

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