Identification of factors associated with sedation tolerance in 5000 patients undergoing outpatient colonoscopy: Canadian tertiary center experience

Table 1 Study population characteristics

Variable		No. (%)
Age (mean ± standard deviation)		56.94 ± 13.06
Female gender		2306 (50.1%)
Indication of the procedure	Screening/surveillance	2892 (57.15%)
	Bleeding	1036 (20.4%)
	Abdominal pain	240 (4.72%)
	Change in bowel movements	690 (13.64%)
	Inflammatory bowel disease	210 (3.99%)
Previous history of surgery	No	2343 (50.7%)
	Yes	2363 (49.26%)
Previous history of colonoscopy and of increased dose of sedation for colonoscopy	Colonoscopy with high dose(Fent > 50 mcg, Midazolam > 3 mg)	3300 (64.1%)
	Colonoscopy with standard dose	470 (9.1%)
	Colonoscopy with unknown sedation dose	305 (5.9%)
	No previous colonoscopy	1076 (20.9%)
Current use of opioids		243 (4.8%)
Current use benzodiazepines		254 (5%)
Current use antidepressants		589 (11.6%)
Current use of opioids or benzodiazepines or antidepressants		826 (16.96%)
Difficult procedure		1038 (19%)
Cardiopulmonary complications		23 (0.4%)
Findings	Any	4139 (78%)
	Polyps	3439 (83%)
	Haemorrhoids	1970 (48%)
	Diverticuli	1050 (35%)
	Colitis	72 (1.7%)
	Stricture	71 (1.7%)
Intervention	Any	3231 (61%)
	Biopsy	2139 (66%)
	Polypectomy	1621 (50%)
Current use alcohol		1930 (46.9%)
Fentanyl dose > 50 mcg		2244 (46%)
Midazolam dose > 3 mg		3000 (62%)
Fentanyl dose > 50 mcg and midazolam > 3 mg		1959 (40%)

Table 2 Multivariate logistic regression analysis for Fentanyl dose > 50 mcg

Variable for fentanyl > 50 mcg	Coefficient	P value	OR (95%CI)
Age	-0.04	0.0001	0.957 (0.952-0.963)
Indication for endoscopy (reference - screening)
Bleeding	-0.04	0.62	0.96 (0.82-1.12)
Abdominal pain	0.29	0.06	1.34 (0.99-1.81)
Change in BM	0.07	0.44	1.08 (0.88-1.31)
IBD	0.46	0.009	1.59 (1.22-2.49)
Intraprocedural characteristics
Difficult procedure	0.45	0.0001	1.57 (1.34-1.81)
Intervention	0.15	0.013	1.17 (1.033-1.32)
Bad preparation	0.16	0.14	1.17 (0.94-1.45)
Past history
Abdominal surgery	0.33	0.0001	1.40 (1.23-1.59)
Colonoscopy	0.26	0.0002	1.30 (1.13-1.49)
Current medications/substance use
Opioids	0.34	0.028	1.40 (1.03-1.91)
Benzodiazepines	0.37	0.017	1.45 (1.06-1.98)
Antidepressants	0.26	0.009	1.30 (1.06-1.60)
Alcohol (any vs none)	0.23	0.022	1.26 (1.03-1.54)

IBD: Inflammatory bowel disease; BM: Bowel movements.

Table 3 Multivariate logistic regression analysis for midazolam dose > 3 mg

Variable for midazolam > 3 mg	Coefficient	P value	OR (95%CI )
Age	-0.05	0.0001	0.94 (0.939-0.95)
Female gender	-0.06	0.0004	0.78 (0.68-0.89)
Indication for endoscopy (reference - screening)
Bleeding	-0.41	0.0001	0.65 (0.56-0.77)
Abdominal pain	0.38	0.032	1.46 (1.03-2.08)
Change in BM	0.02	0.849	1.02 (0.82-1.25)
IBD	0.19	0.346	1.21 (0.81-1.80)
Intraprocedural characteristics
Difficult procedure	0.50	0.0001	1.64 (1.38-1.96)
Past history
Abdominal surgery	0.31	0.0001	1.37 (1.20-1.57)
Medication/substance use
Opioids	0.38	0.025	1.47 (1.04-2.07)
Antidepressants	0.33	0.018	1.39 (1.11-1.73)

IBD: Inflammatory bowel disease; BM: Bowel movements.

Table 4 Multivariate regression analysis of both Fentanyl > 50 mcg and Midazolam > 3 mg

Variable for Fentanyl > 50 mcg and midazolam > 3 mg	Coefficient	P value	OR (95%CI)
Age	-0.04	< 0.0001	0.95 (0.94-0.95)
Indication for endoscopy (reference - screening)
Bleeding	-0.11	0.18	0.89 (0.76-1.05)
Abdominal pain	0.37	0.01	1.45 (1.08-1.96)
Change in BM	0.13	0.18	1.14 (0.93-1.40)
IBD	0.37	0.02	1.45 (1.04-2.032)
Intraprocedural characteristics
Difficult procedure	0.55	< 0.0001	1.73 (1.48-2.03)
Interventions	0.1	0.12	1.10 (0.97-1.25)
Past history
Abdominal surgery	0.30	< 0.0001	1.33 (1.17-1.52)
Colonoscopy	0.33	0.0001	1.39 (1.21-1.60)
Medication/substance use
Opioids	0.41	0.46	0.49 (0.07-3.36)
Benzodazepines	0.36	0.36	3.76 (0.21-64)
Antidepressants	0.22	0.6	0.48 (0.03-7.76)
Alcohol	0.23	0.02	1.26 (1.03-1.54)

BM: Bowel movements; IBD: Inflammatory bowel disease.

Table 5 Multivariable prediction model for high Fentanyl and Midazolam doses

Pre-procedural variables	Measurement units	Odds ratio, 95%CI; P value
Age	10-yr	0.62, 0.52-0.73; P < 0.0001
Gender	Female vs male	2.31, 1.32-4.05; P = 0.01
Previous colonoscopy with high sedation	Yes vs no	1.98, 1.15-3.42; P = 0.02
Previous surgery	Yes vs no	1.33, 0.78-2.25; P = 0.25
Current use of opioids, benzodiazepines or antidepressants	Yes vs no	2.50, 1.47-4.27; P = 0.004
Indications (reference - screening)	Bleeding	1.90, 1.03-3.51; P = 0.04
	Abdominal pain	3.07, 1.29-7.31; P = 0.01
	Change in BM	1.45, 0.71-2.97; P = 0.30
	IBD	3.01, 1.43-6.35; P = 0.01

BM: Bowel movements; IBD: Inflammatory bowel disease.

Table 6 Performance of prediction model using variable sedation doses cut-offs

Fentanyl (mcg)	Midazolam (mg)	AUC	Prevalence rate
> 50	> 3	0.67	43%
> 50	> 4	0.70	22%
> 75	> 3	0.68	23%
> 75	> 4	0.70	18%
> 100	> 3	0.76	2%
> 100	> 4	0.77	2%

AUC: Area under the curve.