# Abstract

 # Abstract

 

## Background and aims: Recent studies have shown that etomidate is associated with fewer serious adverse events than propofol and has a noninferior sedative effect. We investigated whether etomidate--midazolam is associated with fewer cardiopulmonary adverse events and has noninferior efficacy compared to propofol--midazolam for screening colonoscopy in the elderly. 

## Methods: A prospective, single-center, double-blinded, randomized controlled trial was performed. Patients aged over 65 years who were scheduled to undergo screening colonoscopy were randomized to receive either etomidate or propofol based on midazolam. The primary outcome was all cardiopulmonary adverse events. The secondary outcomes were vital sign fluctuation (VSF), adverse events disturbing the procedure, and sedation-related outcomes. 

## Results: The incidence of cardiopulmonary adverse events was higher in the propofol group (72.6%) than in the etomidate group (54.8%) ( \*P = \*.040). VSF was detected in 17 (27.4%) and 31 (50.0%) patients in the etomidate and propofol groups, respectively ( \*P = \*.010). The incidence rate of adverse events disturbing the procedure was significantly higher in the etomidate group (25.8%) than in the propofol group (8.1%) (\*P = \*.008). Moreover, the incidence rate of myoclonus was significantly higher in the etomidate group (16.1%) than in the propofol group (1.6%) ( \*P = \*.004). There was no statistical significance between the 2 groups with respect to sedation times and sedation-related outcomes including patients' and endoscopist's satisfaction. In the multivariate analysis, the etomidate group had significantly low odds ratio (OR) associated with VSF (OR: 0.407, confidence interval: 0.179--0.926, \*P = \*.032). 

## Conclusions: We recommend using etomidate--midazolam in patients with high ASA score or vulnerable to risk factors; propofol--midazolam may be used as a guideline in patients with low ASA score. # Results 

## Demographic and baseline characteristics Initially, 130 patients aged over 65 years were assessed. Among them, six patients were excluded because of adrenocortical insufficiency (n = 1), desire to undergo endoscopy without sedation (n = 3), hypersensitivity to the drug (n = 1), or previous history of adverse events with sedation (n = 1) (Fig. [1](#)). Finally, a total of 124 patients aged over 65 years were enrolled, analyzed, and randomly assigned to 2 groups: propofol group (n = 62) and etomidate group (n = 62). The baseline characteristics including age, sex, procedure type, body mass index, smoking and alcohol history, outpatient status, anticoagulant use, ASA score, modified Mallampati score, and underlying diseases were not significantly different in the 2 groups (Table [1](#)). Additionally, there was no difference in interventional procedures such as polypectomy (*P* = .773), biopsy ( *P* = .930), and epinephrine injection ( \*P = \*.934). Sedation-related outcomes such as induction time ( \*P = \*.833), total procedure time ( \*P = \*.111) and awake time (\*P = \*.070) were not different (Table [2](#)). <figure> <p><img src="" /></p> <figcaption>Assembly of patients. Flow chart showed the recruitment of the study patients.</figcaption> </figure> ::::table-wrap

::: caption
Baseline characteristics.
:::

![](<>):::: ::::table-wrap
::: caption
Procedure and sedation-related outcomes.
:::

![](<>):::: 

## Safety-related outcomes The incidence rate of all cardiopulmonary adverse events was significantly higher in the propofol group (72.6%) than in the etomidate group (54.8%) ( \*P = \*.040) (Fig. [2](#)). In both groups, there were no major adverse events including endotracheal intubation, permanent neurological impairment, and death. The incidence rate of VSF was significantly higher in the propofol group (50.0%) than in the etomidate group (27.4%) ( \*P = \*.010). In addition, the incidence rate of transient hypotension was significantly higher in the propofol group (41.9%) than in the etomidate group (24.2%) (\*P = \*.036). In contrast, the incidence rate of adverse events disturbing the procedure was significantly higher in the etomidate group (25.8%) than in the propofol group (8.1%) (\*P = \*.008). The incidence rate of myoclonus was significantly higher in the etomidate group (16.1%) than in the propofol group (1.6%) (\*P = \*.004) (Table [3](#)). <figure> <p><img src="" /></p> <figcaption>Assessment of adverse events. ∗Statistical significance between the 2 groups was tested by chi-square analysis for the excellent group.</figcaption> </figure> ::::table-wrap
::: caption
Major and minor adverse events.
:::

![](<>):::: When vital sign changes over time were diagrammed on a scatter plot up to 35 minutes, there was a significant difference in change in median SBP with passing time between the 2 groups (\*P = \*.020) (Fig. [3](#)A). Median HR significantly increased over time, but there was no significant difference between the 2 groups (Fig. [3](#)B). Median SpO2 was sustained above 98% on 2 L/min oxygen during the procedure. There was no significant difference over time between the 2 groups (Fig. [3](#)C). <figure> <p><img src="" /></p> <figcaption>Time course of vital signs fluctuation. (A) Systolic blood pressure (mm Hg), (B) heart rate (beats/min), (C) peripheral oxygen saturation (as a percentage). SBP = systolic blood pressure, HR = heart rate, SpO2 = peripheral oxygen saturation.</figcaption> </figure> Multivariate analysis of VSF with logistic regression showed that the etomidate group had significantly low odds ratio (OR) associated with VSF (OR: 0.407, confidence interval: 0.179--0.926, \*P = \*.032) (Table [4](#)). ::::table-wrap
::: caption
Multivariate analysis for vital signs fluctuation.
:::

![](<>):::: 

## Efficacy-related outcomes Outcomes related to the efficacy of sedation including patients' satisfaction, endoscopist's satisfaction, postprocedural abdominal pain, and postprocedural nausea or vomiting are shown in Table [2](#). There was no significant difference in patients' satisfaction (\*P = \*.130) and endoscopist's satisfaction (\*P = \*.743) between the 2 groups. In addition, differences in patients' postprocedural abdominal pain ( \*P = \*.763) and nausea or vomiting ( \*P = \*.075) between the 2 groups were not statistically significant. Moreover, the frequency of recall was not significantly different in both the groups (propofol group: 2/62 [3.2%], etomidate group: 5/62 [8.1%], \*P = \*.439).


Extracted trial result:
Outcome: induction time (continuous)
Intervention: etomidate
Comparator: propofol based on midazolam
Notes: found in table 2