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Anesthetic strategy for obese patients during gastroscopy: deep sedation or conscious sedation? A prospective randomized controlled trial

A Letter to the Editor to this article was published on 11 June 2021



This paper aims to compare the incidence of SpO2 values < 95% and < 90% of the obese patients between conscious sedation and deep sedation and whether conscious sedation was superior to the deep sedation for obese patients during diagnostic gastroscopy.


Obese patients undergoing diagnostic gastroscopy were randomly assigned to two different intervention groups: group CS (conscious sedation) or group DS (deep sedation). Group CS patients were managed by conscious sedation [Modified Observer Assessment of Alertness/Sedation (MOAA/S) at 4–5] protocol, and group DS patients were managed by deep sedation (MOAA/S at ≤ 2) protocol. Propofol and sufentanil (0.1 and 0.05 mg/kg) were, respectively, infused for sedation and analgesia in CS and DS protocols. The primary endpoints were to compare the incidence of SpO2 values < 95% and < 90% of the patients between the two groups. The incidence of successful sedation, satisfaction scores of patients and endoscopist were assessed as secondary endpoints.


115 obese patients (59 in group CS and 56 in group DS) were enrolled in this study. The incidences of SpO2 < 95% and < 90% in group CS (42.4% and 6.8%) were significantly lower than those in group DS (69.6% and 19.6%, with P = 0.003 and 0.041, respectively). The incidence of successful sedation was similar between groups (86.4% vs 89.3%, P = 0.641). Patient satisfaction scores and endoscopist satisfaction scores were both similar between groups (P = 0.548 and 0.171).


Conscious sedation with propofol and sufentanil (0.1 mg/kg) reduced the incidence of hypoxic events without affecting gastroscopy procedure and satisfaction compared with the deep sedation for obese patients during diagnostic gastroscopy.

Trial registration

ChiCTR-1900024894; registration date, July 31, 2019.

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Fig. 1

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.


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The authors are grateful to all participants for their cooperation.


This study was supported by a grant from the Science and Technology Department of Jiaxing City, China (No. 2019AD32148). The granting institution did not play any role in the design collection, analysis, or interpretation of the data for the study, or in the writing of the manuscript.

Author information




SK was involved in project development, data collection, and major manuscript writing. JL and HZ were involved in the project development and manuscript editing. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Hong-mei Zhou.

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Conflict of interest

The authors declare that they have no conflict of interest.

Ethics approval

The Ethics Committee of the Second Affiliated Hospital of Jiaxing University approved this randomized controlled trial (JXEY-2019JX178).

Consent to participate

Written informed consent was obtained from each patient.

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Kang, S., Lu, J. & Zhou, Hm. Anesthetic strategy for obese patients during gastroscopy: deep sedation or conscious sedation? A prospective randomized controlled trial. J Anesth 35, 555–562 (2021).

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  • Conscious sedation
  • Obesity
  • Hypoxemia
  • Gastroscopy
  • Propofol