Table 2. Univariable logistic regression analysis of covariates for postoperative pulmonary complications after laparoscopic gastric or colorectal cancer surgery.

Variables				Odds Ratio (95% CIa)	P–value
Sex: male				0.62 (0.40–0.95)	0.028
Age, year				1.02 (1.01–1.04)	0.006
Body mass index, kg m–2				0.90 (0.94–1.06)	0.895
Comorbidities at surgery
	ASA classification
			1	1	(0.174)
			2	1.56 (0.97–2.52)	0.066
			≥ 3	1.56 (0.73–3.34)	0.251
	Charlson comorbidity index
			≥ 3 (vs 0–2)	1.31 (0.89–1.94)	0.173
	Asthma			1.12 (0.32–3.85)	0.863
	Chronic obstructive pulmonary disease			1.22 (0.27–5.56)	0.800
Characteristics of surgery
	Type of surgery
		Colon or rectum		1	(<0.001)
		Gastric		2.79 (1.87–4.17)	<0.001
	Surgery time, min			1.01 (1.00–1.01)	<0.001
	Intraoperative peak airway pressure
		Mean value, cm H2O		0.97 (0.93–1.01)	0.180
		Maximum value, cm H2O		0.97 (0.94–1.01)	0.101
	Intraoperative total fluid input, L			1.22 (1.01–1.67)	0.035
	Intraoperative packed RBC transfusion			2.47 (1.60–3.82)	<0.001
	Postoperative ICU admission			1.24 (0.68–2.28)	0.482
Year of surgery
	2010–2012			1	(0.270)
	2013–2015			0.90 (0.59–1.36)	0.613
	2016–2017			0.60 (0.33–1.11)	0.106
Preoperative spirometry test
	Preoperative FEV1 (%)			0.99 (0.98–1.00)	0.002
	Preoperative FVC (%)			0.98 (0.97–0.99)	0.001
	Preoperative FEV1/FVC (%)			0.98 (0.97–1.00)	0.105

All covariates of P < 0.1 in univariable logistic regression analysis were included in multivariable logistic regression analysis.

^aCI, Confidence interval; ASA, American society of anesthesiologists; RBC, Red blood cell; ICU, Intensive care unit.