The addition of capnography to standard monitoring reduces hypoxemic events during gastrointestinal endoscopic sedation: a systematic review and meta-analysis

Figures & data

Figure 1 Flow diagram of study searching and selection process.

Abbreviation: RCT, randomized controlled trial.

Table 1 The main characteristics of the studies included in the meta-analysis

Study (publication year)	Number (cap, control)	Population and procedures	Sedatives, depth of sedation	Duration of procedures (cap vs control, minute)	Definition of hypoxemia
Lightdale et al (2006)^Citation16	163 (83, 80)	ASA 1–2, children (0–19 years), endoscopy and colonoscopy	Fentanyl and midazolam, moderate	Endoscopy: 10 (0–24) vs 10 (4–25), colonoscopy: 39 (34–67) vs 40 (15–69)	SaO2 <95% for 5 seconds
Qadeer et al (2009)^Citation17	247 (124, 123)	ASA 1–3, adults, ERCP or EUS	Midazolam in combination with meperidine or fentanyl, N/A	37.2 (16.1) vs 34.4 (12.5)	SaO2 <90% for 15 seconds
Beitz et al (2012)^Citation7	757 (383, 374)	ASA 1–3, adults, colonoscopy	Propofol, adequate	35.9 (22.0) vs 33.8 (20.6)	Fall in SaO2 ≥5% or <90%
Slagelse et al (2013)^Citation18	540 (263, 277)	ASA 1–3, adults, endoscopy or colonoscopy	Propofol, N/A	23.6 (12–30) vs 24 (13–31)	SaO2 <92%
Friedrich-Rust et al (2014)^Citation19	533 (267, 266)	ASA 1–3, adults, colonoscopy alone or in combination with EGD	Propofol in combination with ketamine, N/A	38 (16) vs 38 (17)	SaO2 <90% for 15 seconds
Klare et al (2016)^Citation9	238 (108, 115)	ASA 1–4, adults, ERCP	Propofol and midazolam, deep	38 (6–165) vs 38 (5–164)	SaO2 <90%
Mehta et al (2016)^Citation6	209 (101, 108)	ASA 1–2, adults, endoscopy	Fentanyl or midazolam or meperidine, moderate	5.6 (2.6) vs 5.6 (2.6)	SaO2 <90% for 10 seconds
Mehta et al (2016)^Citation6	231 (117, 114)	ASA 1–2, adults, colonoscopy	Fentanyl or midazolam or meperidine, moderate	17.3 (7.3) vs 17.4 (7.5)	SaO2 <90% for 10 seconds
Riphaus et al (2017)^Citation20	170 (83, 87)	ASA 1–3, adults, interventional endoscopy (EUS or other interventional procedures)	Midazolam and propofol, adequate	25 vs 26	SaO2 <90%

Notes: Duration of procedures are presented as mean (SD) or median (interquartile range).

Abbreviations: cap, capnography; ASA, American Society of Anesthesiologists; ERCP, endoscopic retrograde cholangiopancreatography; EUS, endoscopic ultrasonography; EGD, esophagogastroduodenoscopy; N/A, not applicable; SaO₂, oxygen saturation.

Figure 2 Forest plot showing the odds ratios and 95% CIs of each study for hypoxemia.

Abbreviations: EGD, esophagogastroduodenoscopy; CFS, colonoscopy.

Figure 3 Forest plot showing the odds ratios and 95% CIs of each study for severe hypoxemia.

Abbreviations: EGD, esophagogastroduodenoscopy; CFS, colonoscopy.

Figure 4 Forest plot showing the odds ratios and 95% CIs of each study for the incidence of apnea.

Abbreviations: EGD, esophagogastroduodenoscopy; CFS, colonoscopy.

Figure 5 Forest plot showing the odds ratios and 95% CIs of each study for the detection of apnea.

Table S1 Risk of bias summary

Study (publication year)	Random sequence generation	Allocation concealment	Blinding of participants and personnel	Blinding of outcome assessment	Incomplete outcome data	Selective reporting
Lightdale et al (2006)^Citation16	Low	Low	Low	Low	Low	Low
Qadeer et al (2009)^Citation17	Low	Low	Low	Low	Low	Low
Beitz et al (2012)^Citation7	Low	High	High	High	Low	Low
Slagelse et al (2013)^Citation18	Low	Low	High	High	Low	Low
Friedrich-Rust et al (2014)^Citation19	Low	Low	High	High	Low	Low
Klare et al (2016)^Citation9	Low	Low	High	High	Low	Low
Mehta et al (2016)^Citation6	Low	Low	Low	Low	Low	Low
Riphaus et al (2017)^Citation20	Low	Low	High	High	Low	Low

Table S2 GRADE approach Date: Question: Capnography monitoring compared to standard monitoring for gastrointestinal procedural sedation Setting: Bibliography:

Certainty assessment							No of patients		Effect		Certainty	Importance
No of studies	Study design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Capnography monitoring	standard monitoring	Relative (95% CI)	Absolute (95% CI)
Hypoxemia (assessed with: oxygen saturation)
9	Randomized trials	Seriousa	Not serious	Not serious	Not serious	None	463/1,529 (30.3%)	622/1,544 (40.3%)	OR 0.61 (0.49–0.77)	111 fewer per 1,000 (from 61 fewer to 154 fewer)	⊕⊕⊕ Moderate	Important
Severe hypoxemia (assessed with: oxygen saturation)
6	Randomized trials	Seriousb	Seriousc	Not serious	Not serious	None	91/1,100 (8.3%)	158/1,100 (14.4%)	OR 0.53 (0.35–0.81)	62 fewer per 1,000 (from 24 fewer to 88 fewer)	⊕⊕ Low	Important
Incidence of apnea (assessed with: capnography)
4	Randomized trials	Not serious	Seriousd	Not serious	Not serious	None	206/425 (48.5%)	241/432 (55.8%)	OR 0.74 (0.39–1.43)	75 fewer per 1,000 (from 86 more to 228 fewer)	⊕⊕⊕ Moderate	Important
Detection of apnea (assessed with: capnography or visual inspection)
2	Randomized trials	Seriouse	Not serious	Not serious	Not serious	None	283/491 (57.6%)	14/489 (2.9%)	OR 44.76 (25.35–79.04)	540 more per 1,000 (from 399 more to 671 more)	⊕⊕⊕ Moderate	Important

Notes:

a In five studies, endoscopy team was not blinded to assignment of patients because of organizational reasons.

b In three studies, endoscopy team was not blinded to assignment of patients.

c I2=75%.

d I2=83%.

e In two studies, endoscopy team was not blinded to assignment of patients.

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