Abstract
Background
During diagnostic gastroscopy, intolerance is usually manifested as retching, coughing, and involuntary movement. Conscious analgesia relieves discomfort while patients continue to breathe spontaneously and remain partly responsive. Oxycodone, a semi-synthetic opioid, may reduce the need for deep propofol sedation. We compared an oxycodone-based conscious analgesia strategy with supplemental low-dose propofol with propofol-based deep sedation in elderly obese patients.
Patients and Methods
In this prospective, single-center, open-label randomized controlled trial, 128 patients aged ≥65 years with a body mass index of 30–39.9 kg/m2 undergoing elective gastroscopy were randomized 1:1 to propofol-based deep sedation (group P) or oxycodone-based conscious analgesia with supplemental low-dose propofol (group OP). The primary outcome was the incidence of hypoxemia, defined as any SpO2 reading <90% during the procedure. Key secondary outcomes were airway interventions, hypotension, propofol consumption, and recovery time.
Results
All 128 randomized patients completed the study. Hypoxemia occurred less frequently in group OP than in group P (10.94% vs 37.50%; relative risk, 0.29; 95% CI, 0.14–0.63; P<0.001). Group OP also required fewer airway interventions (10.94% vs 37.50%; P<0.001), and mask-assisted ventilation was required less often (1.56% vs 32.81%; P<0.001). Hypotension was less frequent (9.38% vs 28.13%; P=0.012), total propofol consumption was lower (0.38±0.13 vs 1.70±0.25 mg/kg; P<0.001), and time to full wakefulness was shorter (3.89±0.73 vs 8.21±1.12 minutes; P<0.001) in group OP.
Conclusion
Compared with propofol-based deep sedation, the oxycodone-based conscious analgesia strategy was associated with a lower incidence of hypoxemia, fewer airway interventions, less hypotension, lower propofol exposure, and faster recovery. These findings reflect a comparison of two sedation strategies and do not establish improved respiratory function.
Keywords: oxycodone, propofol, conscious analgesia, elderly obese patients, gastroscopy
Introduction
Gastroscopy is a cornerstone diagnostic and therapeutic procedure for upper gastrointestinal diseases. During diagnostic gastroscopy, patient intolerance is commonly related to anxiety, gagging, coughing, and involuntary movement rather than severe procedural pain, necessitating appropriate sedation or analgesia to ensure patient tolerance and procedural success.1,2 Propofol is widely used because of its rapid onset and short duration of action.3,4 However, deep propofol sedation can cause dose-dependent respiratory and cardiovascular depression, including hypoxemia and hypotension.3,5 These adverse effects are particularly pronounced in elderly obese patients.6 Aging reduces cardiopulmonary reserve, alters pharmacokinetics and pharmacodynamics and increases sensitivity to sedative agents.7 Obesity further exacerbates these risks due to decreased functional residual capacity, increased oxygen consumption, and a higher prevalence of obstructive sleep apnea, all of which predispose patients to peri-procedural hypoxemia.8,9 Therefore, optimizing sedation strategies in elderly obese patients remains a significant clinical challenge.10–12
Conscious analgesia is a strategy that combines analgesia with light-to-moderate sedation while preserving spontaneous ventilation, airway reflexes, and purposeful responsiveness.13 In elderly obese patients, this approach may reduce exposure to deep sedation while maintaining patient comfort and acceptable procedural conditions. Opioids play a central role in this approach.14 Oxycodone is a semi-synthetic opioid acting on both μ- and κ-opioid receptors and provides effective visceral analgesia. Previous evidence suggests that oxycodone-based regimens may reduce propofol requirements during gastroscopy.13 However, evidence regarding the respiratory safety, hemodynamic effects, and procedural efficacy of this strategy in elderly obese patients remains limited.
In our previous randomized controlled study, oxycodone-based conscious analgesia improved the success of initial gastroscope insertion and reduced the need for rescue propofol in patients at high risk of aspiration.13 However, oxycodone alone was insufficient for some patients, and supplemental propofol was required to facilitate smooth gastroscope insertion and procedural completion.15 We therefore developed an optimized strategy combining oxycodone as baseline analgesic with supplemental low-dose propofol to reduce overall propofol exposure while maintaining procedural feasibility.
The present prospective randomized controlled trial compared an oxycodone-based conscious analgesia strategy supplemented with low-dose propofol with standard propofol-based deep sedation in elderly obese patients undergoing gastroscopy. We evaluated its effects on hypoxemia, hemodynamic events, propofol consumption, recovery, and procedural feasibility.
Materials and Methods
Study Design
This prospective, single-center, open-label, randomized controlled trial was conducted in accordance with the Declaration of Helsinki and approved by the Institutional Review Board of the Third Xiangya Hospital, Central South University (Approval No. R21054). The trial was registered at chictr.org.cn (ChiCTR-2100053142, principal investigator: Huan Chang). Written informed consent was obtained from all participants prior to enrollment. The study was designed as a pragmatic comparison of two clinically relevant sedation strategies with different target sedation depths, rather than as a pharmacological head-to-head comparison under equivalent sedation depth.
Participants
Eligible patients were aged ≥65 years, had a body mass index (BMI) of 30–39.9 kg/m2, were classified as American Society of Anesthesiologists (ASA) physical status II–III, and were scheduled for elective outpatient gastroscopy. The exclusion criteria were: (1) Mallampati IV; (2) a known difficult airway; (3) severe obstructive sleep apnea requiring continuous positive airway pressure(CPAP); (4) New York Heart Association functional class (NYHA) III–IV heart failure; (5) Severe chronic obstructive pulmonary disease (COPD); (6) severe hepatic or renal dysfunction; (7) recent opioid or sedative use.
Randomization and Blinding
Patients were randomly assigned in a 1:1 ratio to group P or group OP using a computer-generated randomization sequence. Because the two groups received different drug regimens and targeted different sedation depths, blinding of the treating anesthesiologist and endoscopist was not feasible. To minimize assessment bias, all outcomes were predefined and recorded according to standardized objective criteria.
Procedures
Before gastroscopy, all patients received standardized pre-procedure instructions regarding cooperation with gastroscope swallowing and breathing techniques, including nasal inhalation and oral exhalation. Pulse oxygen saturation (SpO2), heart rate (HR), respiratory rate (RR), and five-lead electrocardiogram (ECG) were monitored continuously throughout the procedure, while non-invasive blood pressure was measured at 2-minute intervals. Adverse events were documented in real time by a dedicated research assistant. Supplemental oxygen at 4 L/min was administered through a nasal cannula for at least 5 minutes before sedation and maintained throughout the procedure. Topical pharyngeal anesthesia with lidocaine spray was applied before gastroscope insertion. Capnography was not used; respiratory monitoring therefore relied on continuous SpO2 and RR monitoring together with clinical observation of airway patency and respiratory effort.
Patients were managed according to two predefined strategies. In group P, an initial bolus of propofol 1.0–1.5 mg/kg, calculated according to actual body weight, was administered intravenously over 30–60 seconds. Additional propofol 0.3–0.5 mg/kg was titrated at 30–60-second intervals until deep sedation, defined as a Modified Observer’s Assessment of Alertness/Sedation (MOAA/S) score of 0–1, was achieved.15,16 During the procedure, rescue propofol 0.2 mg/kg was administered if the patient exhibited movement, coughing, or gagging. Sedation depth was continuously assessed by the anesthesiologist, and propofol dosing was adjusted accordingly.
In group OP, oxycodone 0.05 mg/kg was administered intravenously over 60 seconds based on ideal body weight calculated using the Devine formula:13,15 ideal body weight (kg) = 50 + 0.91 × (height in cm − 152.4) for males and 45.5 + 0.91 × (height in cm − 152.4) for females. Five minutes later, a fixed initial dose of propofol 0.3 mg/kg was administered intravenously over 30 seconds. This conservative supplemental dose was selected on the basis of previous experience with low-dose propofol as an adjunct to analgesic-based endoscopic sedation and our preliminary clinical experience, with the aim of achieving moderate rather than deep sedation.17 The target sedation level was moderate sedation, defined as a MOAA/S score of 2–3. If the MOAA/S score decreased to 0–1, no additional propofol was administered until the patient returned to the target range. Rescue propofol 0.2 mg/kg per bolus was administered only when movement interfered with gastroscope insertion or visualization, persistent coughing or retching occurred, or the patient experienced significant discomfort.
Following the gastroscopy, every patient was transferred to the post-anesthesia care unit (PACU) and monitored until achieving a Modified Aldrete score of 10. Postoperative nausea, vomiting, dizziness, and other adverse events were assessed during the predefined 4-hour follow-up period. Adverse events occurring beyond this period were not systematically collected. All gastroscopic examinations were performed by an experienced endoscopist to maintain procedural consistency.
Adverse Events and Management
Airway interventions were performed when clinically indicated. If SpO2 decreased below 90% or showed a persistent downward trend, appropriate interventions were performed, including: chin lift or jaw thrust, increasing oxygen flow, and/or temporary suspension of the procedure. If necessary, more advanced interventions such as mask-assisted ventilation were performed. The need for airway intervention was recorded.
Hypertension was defined as an increase in mean arterial pressure (MAP) exceeding 20% from baseline or a systolic blood pressure (SBP) ≥140 mmHg. Hypotension was defined as a decrease in MAP of > 20% from baseline or an SBP ≤90 mmHg. For hypertension management, urapidil (5–10 mg) was administered as needed, whereas ephedrine (3–6 mg) was utilized to address hypotension. Tachycardia was defined as a HR > 100 beats/min together with an increase of > 20% from baseline, while bradycardia was indicated by an HR < 50 beats/min. Persistent tachycardia was managed with esmolol (10–20 mg), and atropine (0.2 mg) was administered when the heart rate fell below 45 beats per minute.
Outcomes
The primary outcome was the incidence of hypoxemia, defined as any SpO2 reading below 90% during the procedure. Secondary outcomes included (1) the frequency of airway interventions (eg, chin lift, jaw thrust, increased oxygen flow, mask-assisted ventilation, or tracheal intubation); (2) changes in intraoperative circulation, including hypertension, hypotension, tachycardia or bradycardia; (3) the maximum percentage decrease in MAP from baseline; (4) use of cardiovascular medication intervention; (5) intraoperative retching and limb movements; (6) procedure duration; (7) total propofol consumption; (8) the time to full wakefulness; (9) postoperative nausea, vomiting and dizziness during the 4-hour follow-up period; (10) patient and endoscopist satisfaction core.
MAP and HR values were recorded and compared at four time points: before anesthesia (T0), three minutes after anesthesia and before cardiovascular medication intervention (T1), at the moment of endoscope insertion (T2), and five minutes after endoscope extraction (T3). The duration of the procedure was defined as the time from the gastroscope insertion to the completion of gastroscopy. The time to full wakefulness was defined as the interval between the completion of gastroscopy and the achievement of a Modified Aldrete score of 10. Patient and endoscopist satisfaction levels were evaluated via a numerical rating scale (NRS) spanning from 0 to 10, where a score of 0 denoted minimal satisfaction and a score of 10 represented maximal satisfaction.
Sample Size Calculation and Statistical Analysis
The sample size was calculated using the PASS software (version 15.0). Based on our preliminary clinical studies, the incidence of hypoxemia (SpO2 <90%) in elderly obese patients undergoing gastroscopy was 38.9% in group P and 12.2% in group OP. To detect this difference with a two-sided α level of 0.05 and a statistical power of 90%, a minimum of 51 patients per group was required. Assuming a dropout rate of approximately 20%, the final sample size was set at 64 patients per group.
The data analysis was conducted using SPSS software (version 26.0, SPSS, Chicago, USA). Continuous variables were expressed as mean ± standard deviation or median (interquartile range), as appropriate, and compared using Student’s t-test or the Mann–Whitney U-test. Categorical variables were presented as numbers and percentages and compared using the chi-square test or Fisher’s exact test. A two-sided p-value <0.05 was considered statistically significant.
For repeated measurements of MAP and HR at four time points (T0–T3), a two-way mixed-design analysis of variance was performed, with group (group P versus group OP) as the between-subjects factor and time (T0, T1, T2, and T3) as the within-subjects factor. The main effects of group and time and the group-by-time interaction were evaluated. Mauchly’s test was used to assess the assumption of sphericity, and the Greenhouse–Geisser correction was applied when this assumption was violated. For between-group comparisons at each time point, independent-samples t-tests with Bonferroni correction were used separately for MAP and HR, with an adjusted significance threshold of P<0.0125 for each set of four comparisons.
For the primary outcome, the relative risk (RR), absolute risk reduction (ARR), and number needed to treat (NNT), together with their corresponding 95% confidence intervals, were calculated. The NNT was calculated as the reciprocal of the ARR, and its 95% confidence interval was obtained by inverting the confidence limits of the ARR. All tests were two-sided, and P<0.05 was considered statistically significant, except for comparisons subject to Bonferroni correction, for which the adjusted significance threshold was applied.
Results
Patient Flow and Enrollment
In total, 152 patients were assessed for eligibility between August 03, 2023 and October 30, 2025. Among them, 24 patients were excluded due to not meeting the inclusion criteria or declining to participate. A total of 128 patients were enrolled and randomized, with 64 patients assigned to group P and 64 to group OP. All randomized patients completed the study and were included in the final analysis. The patient inclusion and allocation process is illustrated in the CONSORT flow diagram (Figure 1).
Figure 1.
Flow diagram of patients’ distribution.
Baseline Characteristics
Baseline characteristics, including age, sex, weight, height, BMI, ASA physical status, Mallampati classification, preoperative SpO2 and hypertension, were comparable between the two groups, with no statistically significant differences (Table 1).
Table 1.
Characteristics of Patients
| Variable | Group P (n=64) | Group OP (n=64) | P value |
|---|---|---|---|
| Age, years | 72.59 ± 4.94 | 72.44 ± 4.56 | 0.853 |
| Male/female, n | 34/30 | 32/32 | 0.860 |
| Weight, kg | 89.73 ± 10.53 | 88.45 ± 8.78 | 0.457 |
| Height, cm | 164.50 ± 8.13 | 164.00 ± 6.60 | 0.725 |
| BMI, kg/m2 | 33.07 ± 1.77 | 32.83 ± 2.05 | 0.493 |
| ASA classification, II/III, n | 42/22 | 40/24 | 0.854 |
| Mallampati classification, I/II/III, n | 27/33/4 | 29/31/4 | 0.935 |
| Preoperative SpO2, (%) | 96.98 ± 1.03 | 96.77 ± 1.28 | 0.289 |
| Preoperative hypertension, n (%) | 32 (50.00%) | 30 (46.88%) | 0.724 |
Abbreviations: Group P, standard propofol-based deep sedation; Group OP, oxycodone-based conscious analgesia with supplemental low-dose propofol; BMI, body mass index; ASA, American society of anesthesiologists.
Intraoperative Respiratory and Circulatory Outcomes
The incidence of hypoxemia (SpO2 <90%) was significantly lower in group OP compared with group P (10.94% vs 37.50%, P < 0.001). The absolute risk reduction in hypoxemia was 26.56%, corresponding to an NNT of 4 (95% CI, 3–9). Airway interventions, including chin lift, jaw thrust, and increased oxygen flow, were less frequent in group OP than in group P (10.94% vs 37.50%, P < 0.001). Mask-assisted ventilation was also less frequently required in group OP (1.56% vs 32.81%, P < 0.001). No patient in either group required tracheal intubation (Table 2).
Table 2.
Intraoperative Respiratory and Circulatory Outcomes Between the Two Groups
| Variable | Group P (n=64) |
Group OP (n=64) |
Relative Risk (95% CI) |
P value |
|---|---|---|---|---|
| Hypoxemia (SpO2 <90%), n (%) | 24 (37.50%) | 7 (10.94%) | 0.29 (0.14–0.63) | <0.001 |
| Airway interventions, n (%) | ||||
| Chin lift, jaw thrust, and increased oxygen flow | 24 (37.50%) | 7 (10.94%) | 0.29 (0.14–0.63) | <0.001 |
| Mask-assisted ventilation | 21 (32.81%) | 1 (1.56%) | 0.05 (0.01–0.34) | <0.001 |
| Tracheal intubation | 0 (0.00%) | 0 (0.00%) | NA | NA |
| Changes in intraoperative circulation, n (%) | ||||
| Hypertension | 0 (0.00%) | 0 (0.00%) | NA | NA |
| Hypotension | 18 (28.13%) | 6 (9.38%) | 0.33 (0.14–0.78) | 0.012 |
| Tachycardia | 4 (6.25%) | 5 (7.81%) | 1.25 (0.35–4.44) | 1.000 |
| Bradycardia | 4 (6.25%) | 3 (4.69%) | 0.75 (0.17–3.22) | 1.000 |
| Maximum decrease in MAP, % | 19.74 ± 8.61 | 12.04 ± 4.96 | −7.69 (−10.15 to −5.24) | <0.001 |
| Cardiovascular medication intervention, n (%) | ||||
| Urapidil | 0 (0.00%) | 0 (0.00%) | NA | NA |
| Ephedrine | 16 (25.00%) | 6 (9.38%) | 0.38 (0.16–0.90) | 0.033 |
| Esmolol | 2 (3.13%) | 1 (1.56%) | 0.50 (0.05–5.38) | 1.000 |
| Atropine | 1 (1.56%) | 1 (1.56%) | 1.00 (0.06–15.64) | 1.000 |
Abbreviations: Group P, standard propofol-based deep sedation; Group OP, oxycodone-based conscious analgesia with supplemental low-dose propofol; SpO2, pulse oxygen saturation; MAP, mean arterial pressure.
The incidence of intraoperative hypotension was significantly lower in group OP than in group P (9.38% vs 28.13%, P = 0.012). The maximum decrease in MAP was significantly smaller in group OP than in group P (12.04 ± 4.96% vs 19.74 ± 8.61%, P < 0.001). No intraoperative hypertension occurred in either group (Table 2). Two-way mixed-design ANOVA showed significant effects of group (P=0.008), time (P<0.001), and the group-by-time interaction (P<0.001) on MAP. (Figure 2A). MAP was comparable between the two groups at T0 (P = 0.230). Compared with Group P, Group OP had significantly higher MAP at T1 (84.62 ± 5.50 vs 77.96 ± 8.31 mmHg, P < 0.001) and T2 (87.65 ± 5.47 vs 81.53 ± 7.66 mmHg, P < 0.001). At T3, no significant difference in MAP was observed between the two groups (P = 0.223) (Figure 2A). The incidences of tachycardia and bradycardia were comparable between groups (Table 2). HR changed significantly over time (P < 0.001), whereas neither the group effect nor the group-by-time interaction was significant (P = 0.326 and P = 0.997, respectively). HR was comparable between the two groups at all time points (all P > 0.05) (Figure 2B). Ephedrine use was also less frequent in group OP (9.38% vs 25.00%, P = 0.033), while the use of urapidil, esmolol, and atropine did not differ between groups (Table 2).
Figure 2.
Changes in mean arterial pressure (MAP, (A) and heart rate (HR, (B) over time. Data are presented as mean ± standard deviation. Statistical analysis was performed using two-way mixed-design repeated-measures ANOVA, followed by post-hoc comparisons with Bonferroni correction. T0, before anesthesia; T1, three minutes after anesthesia and before cardiovascular intervention; T2, at endoscope insertion; T3, five minutes after endoscope withdrawal. *** P<0.001.
Procedural and Sedation Outcomes
Procedure duration was comparable between the two groups (6.21 ± 1.15 min vs 6.10 ± 1.21 min, P = 0.627) (Table 3). Intraoperative retching occurred in 7 patients (10.94%) in group OP and 2 patients (3.13%) in group P, with no statistically significant difference (P = 0.164). Similarly, intraoperative limb movements (12.50% vs 4.69%, P = 0.206) and requiring rescue propofol (15.63% vs 7.81%, P = 0.272) were comparable between two groups. However, total propofol consumption was markedly lower in group OP than in group P (0.38 ± 0.13 mg/kg vs 1.70 ± 0.25 mg/kg, P < 0.001), representing an approximately 77.65% reduction. The time to full wakefulness (3.89 ± 0.73 min vs 8.21 ± 1.12 min, P < 0.001) and PACU stay duration (10.53 ± 1.15 min vs 17.79 ± 1.75 min, P < 0.001) were significantly shorter in group OP compared with group P (Table 3).
Table 3.
Procedural and Sedation Outcomes Between the Two Groups
| Variable | Group P (n=64) | Group OP (n=64) | Relative Risk (95% CI) | P value |
|---|---|---|---|---|
| Procedure duration, minutes | 6.10 ± 1.21 | 6.21 ± 1.15 | 0.10 (−0.31 to 0.51) | 0.627 |
| Intraoperative retching, n (%) | 2 (3.13%) | 7 (10.94%) | 3.50 (0.76–16.21) | 0.164 |
| Intraoperative limb movements, n (%) | 3 (4.69%) | 8 (12.50%) | 2.67 (0.74–9.60) | 0.206 |
| Patients requiring rescue propofol, n (%) | 5 (7.81%) | 10 (15.63%) | 2.00 (0.72–5.52) | 0.272 |
| Total propofol consumption, mg/kg | 1.70 ± 0.25 | 0.38 ± 0.13 | −1.31 (−1.38 to −1.24) | <0.001 |
| Time to full wakefulness, minutes | 8.21 ± 1.12 | 3.89 ± 0.73 | −4.31 (−4.64 to −3.98) | <0.001 |
| PACU stay duration, (min) | 17.79 ± 1.75 | 10.53 ± 1.15 | −7.26 (−7.78 to −6.74) | <0.001 |
Abbreviations: Group P, standard propofol-based deep sedation; Group OP, oxycodone-based conscious analgesia with supplemental low-dose propofol.
Postoperative Adverse Events and Satisfaction Scores from the Patients and Endoscopists
The incidences of postoperative nausea, vomiting, and dizziness were comparable between the two groups (all P > 0.05). Patients’ and endoscopist’s satisfaction scores also showed no significant differences between two groups (Table 4).
Table 4.
Postoperative Adverse Events and Satisfaction Scores Between the Two Groups
| Variable | Group P (n=64) | Group OP (n=64) | P value |
|---|---|---|---|
| Postoperative nausea, n (%) | 3 (4.69%) | 5 (7.81%) | 0.718 |
| Postoperative vomiting, n (%) | 1 (1.56%) | 2 (3.13%) | 1.000 |
| Postoperative dizziness, n (%) | 10 (15.63%) | 6 (9.38%) | 0.424 |
| Patients’ satisfaction scores | 9.13 ± 0.70 | 9.16 ± 0.72 | 0.804 |
| Endoscopist’s satisfaction scores | 9.09 ± 0.68 | 9.08 ± 0.67 | 0.897 |
Abbreviations: Group P, standard propofol-based deep sedation; Group OP, oxycodone-based conscious analgesia with supplemental low-dose propofol.
Discussion
The present study found that the oxycodone-based conscious analgesia strategy supplemented with low-dose propofol was associated with lower incidences of hypoxemia and hypotension, fewer airway interventions, reduced propofol consumption, and faster recovery. Compared with the standard propofol-based deep sedation strategy, the OP strategy was associated with a lower incidence of hypoxemia, fewer airway interventions, markedly less mask-assisted ventilation, lower incidence of hypotension, reduced MAP decline, lower ephedrine requirement, shorter recovery, and substantially lower total propofol consumption.
Elderly obese patients are particularly vulnerable to sedation-related respiratory events. Age-related decline in cardiopulmonary reserve, obesity-associated reduction in functional residual capacity, and increased risk of upper airway obstruction may together increase the likelihood of hypoxemia during deep sedation.18,19 In the present study, the incidence of hypoxemia was markedly lower in group OP than in group P. More importantly, mask-assisted ventilation was required much less frequently in group OP, and no patient required tracheal intubation. These findings suggest that the oxycodone-based strategy may provide a wider respiratory safety margin in this population.
Pharmacokinetic and pharmacodynamic considerations further support the rationale for the OP strategy. Aging is associated with increased brain sensitivity to propofol, including a lower concentration required for loss of consciousness, and reduced drug clearance,20 while obesity alters its volume of distribution and dose–concentration relationship; together, these changes may place elderly obese patients at increased risk of dose-dependent respiratory and cardiovascular depression.21,22 Conversely, oxycodone, when administered conservatively according to ideal body weight (0.05 mg/kg IBW), provides effective visceral analgesia and may reduce the amount of propofol required to achieve acceptable procedural conditions.13 The 77.65% reduction in propofol consumption observed with the OP strategy therefore likely reflects the combined effects of opioid-based analgesia, reduced propofol exposure, and the lighter target sedation depth, and may have contributed to the lower incidences of hypoxemia and hypotension observed in this vulnerable population. These pharmacological considerations further support the clinical rationale for an analgesia-dominant, moderate-sedation approach in elderly obese patients undergoing gastroscopy.
The circulatory findings were consistent with this interpretation. Propofol-induced vasodilation and myocardial depression are important contributors to peri-procedural hypotension, especially in elderly patients with reduced cardiovascular reserve.23,24 In this study, group OP showed a lower incidence of hypotension, smaller maximum MAP decrease, and lower ephedrine requirement. These results suggest that reducing propofol exposure may also improve hemodynamic stability during gastroscopy.
An important concern with a conscious analgesia-based strategy is whether a lighter sedation level may compromise procedural conditions.21 In the present study, procedure duration was comparable between groups. Although intraoperative retching and limb movements were numerically more frequent in group OP, the differences were not statistically significant. Patient and endoscopist satisfaction scores were also comparable. These findings indicate that the OP strategy maintained procedural feasibility and tolerability despite targeting a lighter sedation depth.
The faster recovery observed in group OP further supports the clinical value of this strategy. Both time to full wakefulness and PACU stay were significantly shorter in group OP, which may be explained by the lower propofol burden.25 In addition, postoperative nausea and vomiting were numerically more frequent in group OP, although these differences did not reach statistical significance. This trend is consistent with the known emetogenic profile of oxycodone, which may have been partially mitigated by the low dose employed (0.05 mg/kg IBW). The absence of statistical significance suggests that the clinical impact of this difference was modest, and overall opioid-related postoperative discomfort was not substantially increased with the OP strategy.26
It should be emphasized that the present study was not designed as a pharmacological head-to-head comparison under equivalent sedation depth. Instead, it compared two clinically relevant sedation strategies: a conventional propofol-based deep sedation strategy and an oxycodone-based conscious analgesia strategy supplemented with low-dose propofol. Therefore, the observed safety benefits likely reflect both reduced propofol exposure and the lighter, analgesia-dominant sedation approach. This design is clinically meaningful because the goal in high-risk patients is not necessarily to achieve equivalent sedation depth, but to maintain procedural feasibility while minimizing sedation-related adverse events.
Our findings extend our previous work on oxycodone-based conscious analgesia. In our earlier randomized study, oxycodone alone improved initial gastroscope insertion success and reduced the need for rescue propofol in patients at high risk of aspiration. However, clinical experience suggested that oxycodone alone may be insufficient for some patients. The present study therefore incorporated a small initial dose of propofol and predefined rescue sedation, creating a more standardized and clinically applicable protocol for elderly obese patients.
Several limitations should be acknowledged. First, this was a single-center study, which may limit generalizability. Second, patients with morbid obesity, difficult airway, severe obstructive sleep apnea requiring CPAP, and severe cardiopulmonary disease were excluded; therefore, the results may not apply to extremely high-risk patients. Third, the open-label design may have introduced performance or assessment bias, particularly for secondary outcomes involving clinical intervention decisions and satisfaction assessments. Nevertheless, the primary outcome was defined using a prespecified objective SpO2 threshold and was continuously monitored. Fourth, the two groups targeted different sedation depths; therefore, the findings should be interpreted as a comparison between two sedation strategies rather than evidence of the independent superiority of oxycodone under equivalent sedation depth. Fifth, tidal volume, lung mechanics and capnography were not used, which may have resulted in undetected episodes of hypoventilation that did not progress to hypoxemia. Although stable tidal volume and end-tidal carbon dioxide waveforms were difficult to obtain consistently during gastroscopy in our preliminary clinical practice, future studies should incorporate more reliable tidal volume and capnographic monitoring. Respiratory assessment in this study focused on the occurrence of hypoxemia based on the prespecified SpO2 threshold and predefined airway interventions; the duration of individual hypoxemic episodes was not a prespecified endpoint. Finally, the study focused on short-term peri-procedural outcomes, and delayed post-discharge adverse events were not systematically assessed. Future studies should include longer postoperative observation and structured post-discharge follow-up.
Conclusion
In elderly obese patients undergoing gastroscopy, an oxycodone-based conscious analgesia strategy supplemented with low-dose propofol was associated with lower incidences of hypoxemia and hypotension, reduced propofol consumption, and faster recovery compared with propofol-based deep sedation. This strategy may represent a feasible alternative for sedation in this high-risk population.
Acknowledgments
We thank our colleagues at the Department of Anesthesiology and the Gastrointestinal Endoscopy Center for their cooperation in facilitating this trial.
Funding Statement
This study was supported by the Natural Science Foundation of Hunan Province (2025JJ80482, 2026JJ50432) and the Youth Innovation Foundation of the First Hospital of Changsha (Y2024-04).
Data Sharing Statement
All data generated or analyzed during this study were included in the published article. Further inquiries about the datasets can be directed to the corresponding author on reasonable request.
Disclosure
The authors report no conflicts of interest in this work.
References
- 1.Tringali A. Sedation and anesthesia in gastrointestinal endoscopy in 2025: how, who, and why. Gastrointest Endosc. 2026;103(3):438–10. doi: 10.1016/j.gie.2025.09.014 [DOI] [PubMed] [Google Scholar]
- 2.Martinez-Gonzalez O, Alonso-Fernandez MA, Garcia-Alonso M, et al. Deep sedation for gastrointestinal endoscopy in elderly patients. Subgroup analysis. Dig Liver Dis. 2025;57(6):1266–1272. doi: 10.1016/j.dld.2024.11.029 [DOI] [PubMed] [Google Scholar]
- 3.Bruni A, Barbara G, Vitello A, Marasco G, Maida M. Sedation in endoscopy: current practices and future innovations. World J Gastrointest Endosc. 2025;17(6):106604. doi: 10.4253/wjge.v17.i6.106604 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Sidhu R, Turnbull D, Haboubi H, et al. British society of gastroenterology guidelines on sedation in gastrointestinal endoscopy. Gut. 2024;73(2):219–245. doi: 10.1136/gutjnl-2023-330396 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Sahinovic MM, Struys M, Absalom AR. Clinical pharmacokinetics and pharmacodynamics of propofol. Clin Pharmacokinet. 2018;57(12):1539–1558. doi: 10.1007/s40262-018-0672-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Terres MT, Assis ML, Da Silveira CB, Amaral S. Remimazolam versus propofol for endoscopy sedation in elderly patients: a systematic review, meta-analysis and trial sequential analysis. Minerva Anestesiol. 2024;90(9):775–784. doi: 10.23736/S0375-9393.24.18027-3 [DOI] [PubMed] [Google Scholar]
- 7.Yahav-Shafir D, Orkin D, Zahavi G, Epstein I, Nadler M, Berkenstadt H. Patient-reported quality of recovery after sedation for endoscopy in the elderly. Gerontology. 2024;70(5):455–460. doi: 10.1159/000536647 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Liu H, Guo P, Chen L, Liu X, Wu H. Effects of anesthetic nasal masks on hypoxemia in overweight/obese patients undergoing gastroscopy: a randomized controlled trial. Eur J Med Res. 2025;30(1):355. doi: 10.1186/s40001-025-02534-2 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Laffin AE, Kendale SM, Huncke TK. Severity and duration of hypoxemia during outpatient endoscopy in obese patients: a retrospective cohort study. Can J Anaesth. 2020;67(9):1182–1189. [DOI] [PubMed] [Google Scholar]
- 10.Yan W, Yan L, Meng W, et al. Effect of nasal mask oxygenation on incidence of hypoxemia during gastroscopy with propofol sedation in patients at risk of hypoxemia: a prospective randomized controlled study. BMC Anesthesiol. 2025;25(1):366. doi: 10.1186/s12871-025-03245-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Qi L, Zhou Z, Peng K, et al. A retrospective analysis of the effects of moderate sedation on the degree of cardia exposure in overweight elderly patients. BMC Anesthesiol. 2025;25(1):484. doi: 10.1186/s12871-025-03387-2 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Zook ZR, Chien S, Deng A, Espiridion E. Post anaesthesia cognitive outcomes in propofol vs ketamine sedation for colonoscopy: a retrospective cohort study. Anesthesiol Perioper Sci. 2025;3:41. doi: 10.1007/s44254-025-00125-2 [DOI] [Google Scholar]
- 13.Chang H, Cheng C, Qing W, et al. Conscious analgesia with oxycodone improves the efficacy and safety in patients at high risk of aspiration during gastroscopy: a randomized double-blind trial. BMC Anesthesiol. 2026;26(1):105. doi: 10.1186/s12871-025-03595-w [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Yang WL, Zhou XY, Jiang WC, Zhang XJ, Zhou D. Opioid analgesics for sedation-based gastrointestinal endoscopy. World J Gastrointest Pharmacol Ther. 2025;16(2):102098. doi: 10.4292/wjgpt.v16.i2.102098 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15.Li YP, Zhou Y. Differential dosing of oxycodone in combination with propofol in diagnostic painless gastroscopy in elderly patients: a prospective randomized controlled trial. Medicine. 2022;101(51):e32427. doi: 10.1097/MD.0000000000032427 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Early DS, Lightdale JR, Vargo JJ, et al. Guidelines for sedation and anesthesia in GI endoscopy. Gastrointest Endosc. 2018;87(2):327–337. doi: 10.1016/j.gie.2017.07.018 [DOI] [PubMed] [Google Scholar]
- 17.Heron V, Golden C, Blum S, et al. Endoscopist-directed propofol as an adjunct to standard sedation: a Canadian experience. J Can Assoc Gastroenterol. 2020;3(3):141–144. doi: 10.1093/jcag/gwz011 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Chen J, Lai L, Zhao S, et al. The effects of ciprofol and propofol on hypoxemia during gastrointestinal endoscopy in overweight and obese patients: a randomized controlled trial. BMC Anesthesiol. 2025;25(1):548. doi: 10.1186/s12871-025-03428-w [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Wang S, Shen N, Wang Y, et al. Bilevel positive airway pressure for gastroscopy with sedation in patients at risk of hypoxemia: a prospective randomized controlled study. J Clin Anesth. 2023;85:111042. doi: 10.1016/j.jclinane.2022.111042 [DOI] [PubMed] [Google Scholar]
- 20.Matsuki Y, Nagata O, Ogino Y, et al. Impact of aging on interactions between opioid and propofol concentrations during total intravenous anesthesia. J Clin Anesth. 2021;71:110245. doi: 10.1016/j.jclinane.2021.110245 [DOI] [PubMed] [Google Scholar]
- 21.Kim DB, Kim JS, Huh CW, et al. Propofol compared with bolus and titrated midazolam for sedation in outpatient colonoscopy: a prospective randomized double-blind study. Gastrointest Endosc. 2021;93(1):201–208. doi: 10.1016/j.gie.2020.05.045 [DOI] [PubMed] [Google Scholar]
- 22.Lu J, Yang D, Wang Y, Yang S, Fan X, Bo L. Effect of propofol sedation via a narrow-bore tube on hypoxemia risk during gastroscopy: a single-center, prospective, randomized controlled trial. BMC Anesthesiol. 2025;25(1):417. doi: 10.1186/s12871-025-03283-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Chen M, Sun Y, Li X, et al. Effectiveness of single loading dose of dexmedetomidine combined with propofol for deep sedation of endoscopic retrograde cholangiopancreatography (ERCP) in elderly patients: a prospective randomized study. BMC Anesthesiol. 2022;22(1):85. doi: 10.1186/s12871-022-01630-8 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Sundararaman L, Goudra B. Sedation for GI endoscopy in the morbidly obese: challenges and possible solutions. J Clin Med. 2024;13(16):4635. doi: 10.3390/jcm13164635 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Barbosa EC, Espirito Santo PA, Baraldo S, Meine GC. Remimazolam versus propofol for sedation in gastrointestinal endoscopic procedures: a systematic review and meta-analysis. Br J Anaesth. 2024;132(6):1219–1229. doi: 10.1016/j.bja.2024.02.005 [DOI] [PubMed] [Google Scholar]
- 26.Kim NS, Lee JS, Park SY, et al. Oxycodone versus fentanyl for intravenous patient-controlled analgesia after laparoscopic supracervical hysterectomy: a prospective, randomized, double-blind study. Medicine. 2017;96(10):e6286. doi: 10.1097/MD.0000000000006286 [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
All data generated or analyzed during this study were included in the published article. Further inquiries about the datasets can be directed to the corresponding author on reasonable request.