Table 2.

Preoperative comorbidities.

Preoperative comorbidity	PCAIB group	PCA group	p
Cardiovascular system
Hypertension	42 (41%)	21 (44%)	0.726
Arrhythmia	9 (9%)	9 (19%)	0.105
Respiratory system
Asthma	6 (6%)	4 (8%)	0.727
Gastrointestinal system
Hepatitis	13 (13%)	7 (15%)	0.741
Gastric ulcer	13 (13%)	6 (13%)	0.983
Urologic system
Renal syndrome	4 (4%)	1 (2%)	1.000
Endocrine system
DM	19 (18%)	8 (17%)	0.790
Thromboembolic events
Cerebral embolism	2 (2%)	1 (2%)	1.000
Myocardial infarction	3 (3%)	2 (4%)	0.653
Smoking	64 (62%)	30 (63%)	0.966

Categorical variables as number of events (n); Chi-square test was used, events less than 5 were compared with Fisher's exact test, and statistical significance was considered when p < 0.05.

PCAIB: patients with interscalene block in combination with intravenous patient-controlled analgesia.

PCA: patients receiving intravenous patient-controlled analgesia alone without interscalene block.