Safety and efficacy of carbon dioxide insufflation during gastric endoscopic submucosal dissection

Table 1 Patients and examination characteristics

Characteristic	CO2 group (n = 36)	Air group (n = 51)	P value
Age, yr	74 (52-87)	70 (45-93)	NS
Sex, male/female	22/14	36/15	NS
FEV1.0%	72 (70-89)	73 (70-93)	NS
%VC	103 (80-102)	109 (80-152)	NS
Location of lesion, n: upper/middle/lower	5/22/9	12/15/24	0.012
En bloc resection, n (%)	36 (100)	51 (100)	NS
Histopathologic type, n: tub1/tub2/por/sig/adenoma	18/3/0/0/15	36/6/2/1/6	0.020
Histologic depth, n: M/SM1/SM2	32/2/2	42/1/8	NS
Histopathologically curative resection, n (%)	31 (86.1)	43 (84.3)	NS
Tumor size, mm	18 (4-75)	17 (3-47)	NS
Resection size, mm	35 (22-110)	37 (23-95)	NS
Procedure time, min	46 (18-194)	48 (15-145)	NS
Dose of diazepam, mg	20 (5-30)	20 (5-30)	NS
Dose of pentazocine, mg	18.8 (7.5-45)	22.5 (7.5-45)	NS
Patients receiving midazolam, n (%)	3 (8.3)	5 (9.8)	NS
Dose of midazolam, mg	10.0 (2.5-20)	7.5 (2.5-10)	NS

Data are presented as n, n (%), or median (range). FEV_1.0%: Forced expiratory volume 1.0 second/forced vital capacity; %VC: Vital capacity; tub1: Well-differentiated tubular adenocarcinoma; tub2: Moderately differentiated tubular adenocarcinoma; por: Poorly differentiated adenocarcinoma; sig: Signet ring cell carcinoma; M: Tumor confined to the mucosa; SM1: Tumor confined to the submucosa and tumor invasion within 0.5 mm of the muscularis mucosae; SM2: Tumor confined to the submucosa and tumor invasion of 0.5 mm or more into the muscularis mucosae; NS: Not significant.

Table 2 Patient characteristics and parameters of arterial blood analysis

Characteristic	CO2 group (n = 12)	Air group (n = 18)	P value
Age, yr	73 (63-82)	70 (45-87)	NS
Procedure time, min	66 (26-156)	56 (23-107)	NS
Dose of diazepam, mg	17.5 (10.0-22.5)	20.0 (5.0-30.0)	NS
Dose of pentazocine, mg	15.0 (15.0-30.0)	22.5 (15.0-37.5)	NS
Patients receiving midazolam, n (%)	1 (8.3)	1 (5.6)	NS
Dose of midazolam, mg	2.5	5
pH value	7.36 (7.34-7.39)	7.36 (7.33-7.40)	NS
PaCO2, mmHg	44.6 (39-53)	45 (40-50)	NS
PaO2, mmHg	168 (68-203)	143 (78-259)	NS
HCO3-, mEq/L	25.1 (23.0-30.0)	25.5 (22.0-27.0)	NS
Base excess, mEq/L	-0.05 (-2-4)	0.3 (-3.1-2.6)	NS

Data are presented as median (range) unless otherwise indicated. PaO₂: Partial pressure of oxygen in arterial blood; PaCO₂: Partial pressure of carbon dioxide in arterial blood; NS: Not significant.

Table 3 Transcutaneous carbon dioxide tension values, transcutaneous oxygen saturation values, and oxygen flow rate

Variable	CO2 group (n = 36)	Air group (n = 51)	P value
Baseline PtcCO2, mmHg	39 (28-52)1	40 (22-51)1	NS
PtcCO2 after ESD, mmHg	50 (41-68)1	50 (40-64)1	NS
Peak PtcCO2, mmHg	52 (43-68)	51 (40-64)	NS
PtcCO2 > 60 mmHg during ESD	3 (8.3)	2 (3.9)	NS
Minimum SpO2, %	98 (90-100)	98 (89-100)	NS
Oxygen flow rate, L/min	2 (1-5)	2 (2-4)	NS

¹The PtcCO₂ increased significantly (P < 0.001) after the procedure. Data are presented as n (%) or median (range). ESD: Endoscopic submucosal dissection; PtcCO₂: Transcutaneous carbon dioxide tension; SpO₂: Transcutaneous oxygen saturation.

Table 4 Complications from endoscopic submucosal dissection, blood parameters, and duration of hospital stay

Variable	CO2 group (n = 36)	Air group (n = 51)	P value
Fever (body temperature > 37.5  °C)	9 (25.0)	9 (17.6)	NS
Pneumonia	3 (8.3)	5 (9.8)	NS
Perforation	1 (2.7)	1 (1.9)	NS
Post-procedure hemorrhage	0	4 (7.8)	NS
Mallory-Weiss tears	0	8 (9.8)	0.013
CRP on day 1 after ESD, mg/dL	0.30 (0.09-6.19)	0.40 (0.04-3.62)	NS
CRP on day 3 after ESD, mg/dL	2.00 (0.18-7.83)	2.00 (0.08-14.20)	NS
WBC on day 1 after ESD, n/μL	9020 (3730-15680)	8090 (4510-13450)	NS
WBC on day 3 after ESD, n/μL	6310 (2560-11200)	6260 (3100-10660)	NS
Hospital stay, d	7 (7-16)	7 (7-20)	NS

Data are presented as n (%) or median (range). ESD: Endoscopic submucosal dissection; CRP: C-reactive protein; WBC: White blood cell.