Perioperative Exhaled Nitric Oxide as an Indicator for Postoperative Pneumonia in Surgical Lung Cancer Patients: A Prospective Cohort Study Based on 183 Cases

Table 1

Baseline and clinical characteristics of the two groups.

	POP group, N = 19	Non-POP group, N = 164	value
Age (years)^#	61.2 ± 9.5	56.0 ± 9.8	0.027
BMI (kg/m^2)^##	22.7 (21.0, 25,9)	22.9 (21.3, 24.8)	0.747
Gender, (n (%))			0.463
Male	10 (52.6)	68 (41.5)
Female	9 (47.4)	96 (58.5)
Smoking status, (n (%))			0.168
Current smoking	8 (42.1)	41 (25.0)
Ex-smokers or nonsmokers	11 (57.9)	123 (75.0)
Pulmonary function
FEV1 (L)^##	2.40 (2.2, 2.8)	2.52 (2.2, 3.0)	0.329
FEV1/FVC^##	79.0.(70.5–83.0)	80.5(76.2–84.3)	0.146
DLCO (mL/mmHg/min)^##	20.5 (18.4, 24.8)	22.1 (19.2, 25.3)	0.242
Comorbidities (n (%))
COPD	4 (21.1)	17 (10.4)	0.243
Diabetes mellitus	2 (10.5)	7 (4.3)	0.237
CVD	4 (21.1)	25 (15.2)	0.510
Clinical stage > II, (n (%))			0.538
Yes	17 (89.5)	135 (82.3)
No	2 (10.5)	29 (17.7)
Resection type, (n (%))			0.376
RUL	5 (26.3)	55 (33.5)
RML	3 (15.8)	15 (9.1)
RLL	6 (31.6)	28 (17.1)
LUL	4 (21.1)	41 (25.0)
LLL	1 (5.3)	25 (15.2)
Blood test
Preoperative WBC (×10^9/L)^#	5.9 ± 1.9	5.8 ± 1.5	0.639
Preoperative N (%)^#	59.6 ± 16.0	57.3 ± 8.6	0.329
Preoperative EO (%)^##	2.3 (1.8,3.7)	2.2 (1.1, 3.4)	0.516
Preoperative albumin (g/L)^#	44.7 ± 3.4	44.4 ± 3.2	0.727
POD1 WBC^##	9.6 (8.2, 12.0)	9.6 (7.9, 11.3)	0.453
POD1 N (%)^##	82.0 (75.0%, 84.9)	78.4 (73.2, 82.6)	0.280
POD1 EO (%)^##	0.4 (0.1,1.8)	0.4 (0.1, 1.4)	0.973
POD1 albumin (g/L)^#	37.9 ± 4.0	39.1 ± 3.4	0.172
Length of stay (days)
Total^##	13.0 (10.0, 19.0)	9.0 (8.0, 10.0)	<0.001
Postoperative^##	7.0 (6.0, 10.0)	4.0 (3.0, 5.0)	<0.001
FeNO value (ppb)
Preoperative FeNO^##	21.0 (18.0, 27.0)	19.0 (14.0, 27.0)	0.276
Postoperative FeNO^##	30.0 (26.0, 38.0)	19.0 (13.0, 26.0)	<0.001
Change in FeNO^##	10.0 (6.0, 22.0)	0.0 (−4.0, 4.0)	<0.001
Amount of blood loss (mL)^##	50.0 (20.0, 200.0)	30.0 (20.0, 50.0)	0.113
Operation time (min)^##	110.0 (80.0, 150.0)	80.0 (60.0, 100.0)	0.002
Duration of antibiotic use (days)^##	5.0 (4.0, 6.0)	2.0 (1.0, 2.0)	0.001
Drainage duration (days)^##	3.0 (3.0, 7.0)	2.0 (1.0, 3.0)	0.001

^#Data with mean ± SD, ^##data with median (interquartile range), and data with significant differences. POP: postoperative pneumonia; BMI: body mass index; current smoking: still smoking in last 3 months; ex-smokers: quit smoking for more than 1 year; COPD: chronic obstructive pulmonary disease; CVD: cardiovascular disease including hypertension and coronary heart disease; DM: diabetes mellitus; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; DLCO: diffusion capacity of the lung for carbon monoxide; FeNO: fractional exhaled nitric oxide; WBC: white blood cell; N: neutrophil granulocyte; EO: eosinophil granulocyte, POD: postoperative day; RUL: right upper lobe; RML: right middle lobe; RLL: right lower lobe; LUL: left upper lobe; LLL: left lower lobe.