The impact of perioperative hydrogen gas inhalation on postoperative recovery in day surgery patients: a research study
Ji S, Xiao Q, Zhang B, Cai R, Jing Y, Yang D, Liu N, Zhang Z, Mei X. · Scientific Reports. Published online 11 July 2026. Publisher accepted manuscript, 30 pages; final volume and article number not verified.
Study at a glance
This randomized study compared hydrogen–oxygen inhalation with nitrogen–oxygen around day surgery. Among 150 analyzed patients, recovery questionnaire scores fell less from baseline with hydrogen. However, the absolute postoperative scores and overall adverse-event rates did not differ significantly. Although 181 patients entered the study, 31 were excluded or had missing data, more often in the control group. The findings are preliminary and do not establish a clinical benefit or long-term safety.
Human
Adults aged 18–80, ASA I–II, elective laparoscopic cholecystectomy or thyroidectomy in a day-surgery pathway.
2 hours before surgery plus 2 hours after surgery via nasal cannula; no inhalation intervention during the anesthetized operation. · Source: 66.7% H₂ / 33.3% O₂. Authors report nasal-cannula H₂ concentration of 2–3%, monitored every 5 minutes; this is distinct from generator composition.
2 hours before surgery and 2 hours after surgery; recovery measured approximately 6 hours postoperatively (actual 4–7 hours). No study inhalation during the anesthetized operation.
QoR-15 decline from baseline: hydrogen: 9 ± 12 points; comparator: 14 ± 13 points; between group: p = 0.008; approximately 5 points less decline. Postoperative absolute QoR-15 score: hydrogen: 133 [121, 141]; comparator: 130 [119, 136]; between group: p = 0.078; not statistically significant. Participants with perioperative adverse events: hydrogen: 11/76 (14.47%); comparator: 18/74 (24.32%); between group: p = 0.127; not statistically significant. Operation duration imbalance: hydrogen: 1.03 hours; comparator: 1.17 hours; between group: p = 0.025.
Single centre, short observation and complete-case analysis after 31 of 181 participants were excluded. Missing data were more common in controls (18 versus 5), and operation duration differed between groups. The significant recovery change score does not imply a significant difference in absolute postoperative QoR-15 or adverse events. Multiple exploratory questionnaire and biochemical analyses were conducted. Sample-size planning used a noninferiority gastrointestinal-complication assumption rather than a direct primary QoR-15 target.
What kind of evidence is this?
Human
Single-centre prospective double-blind randomized parallel clinical study; computer-generated allocation, opaque envelopes; gas preparer unblinded.
Critical care and ischemia-reperfusion
Inhaled H₂
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
Adults aged 18–80, ASA I–II, elective laparoscopic cholecystectomy or thyroidectomy in a day-surgery pathway.
181 enrolled/assigned: 86 hydrogen and 95 control. Complete-case analysis: 150 (76 hydrogen, 74 control). Thirty-one were not analyzed: 3 surgical reasons, 5 conversions/transfers and 23 missing-data cases (5 hydrogen, 18 control). The abstract calls 150 enrolled, unlike the Methods and flow.
2 hours before surgery and 2 hours after surgery; recovery measured approximately 6 hours postoperatively (actual 4–7 hours). No study inhalation during the anesthetized operation.
2 hours before surgery plus 2 hours after surgery via nasal cannula; no inhalation intervention during the anesthetized operation.
Hydrogen and oxygen source-gas mixture; source composition is distinct from inspired concentration.
Source: 66.7% H₂ / 33.3% O₂. Authors report nasal-cannula H₂ concentration of 2–3%, monitored every 5 minutes; this is distinct from generator composition.
Reported total source flow 900 mL/min; source component outputs reported as 600 mL/min H₂ and 300 mL/min O₂. These are not measured patient uptake.
33.3% O₂ in both hydrogen and nitrogen comparator source mixtures.
66.7% nitrogen / 33.3% oxygen, total 900 mL/min, same timing; background perioperative care in both groups.
Outcomes and reported result
Change in QoR-15 total recovery score from preoperative baseline to approximately 6 hours after surgery (actual reassessment 4–7 hours).
QoR-15 decline from baseline: hydrogen: 9 ± 12 points; comparator: 14 ± 13 points; between group: p = 0.008; approximately 5 points less decline. Postoperative absolute QoR-15 score: hydrogen: 133 [121, 141]; comparator: 130 [119, 136]; between group: p = 0.078; not statistically significant. Participants with perioperative adverse events: hydrogen: 11/76 (14.47%); comparator: 18/74 (24.32%); between group: p = 0.127; not statistically significant. Operation duration imbalance: hydrogen: 1.03 hours; comparator: 1.17 hours; between group: p = 0.025.
The available main full text was reviewed for methods, results, limitations and declarations. Remaining source-specific uncertainties are stated in this record.
No hypoxia or nasal bleeding directly attributed to inhalation reported during the short observation period. Events included dizziness, nausea, vomiting and abdominal bloating. The total adverse-event difference was not significant; this trial does not establish long-term or consumer-device safety.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Single centre, short observation and complete-case analysis after 31 of 181 participants were excluded. Missing data were more common in controls (18 versus 5), and operation duration differed between groups. The significant recovery change score does not imply a significant difference in absolute postoperative QoR-15 or adverse events. Multiple exploratory questionnaire and biochemical analyses were conducted. Sample-size planning used a noninferiority gastrointestinal-complication assumption rather than a direct primary QoR-15 target.
Adults aged 18–80, ASA I–II, elective laparoscopic cholecystectomy or thyroidectomy in a day-surgery pathway. Findings apply only to the studied design and exposure; no treatment or device recommendation.
Clinical Research Award, First Affiliated Hospital of Xi’an Jiaotong University: XJTU1AF-CRF-2023-020.
Authors declare no competing interests.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 42436242 · DOI: 10.1038/s41598-026-61287-y
Complete 30-page publisher accepted manuscript, labelled Article in Press; not the final typeset version.
AI-assisted editorial review of the available main full text, 29 October 2026. The source version and access limitations are stated in this record. No independent clinical or statistical assessment has been performed.
PDF pages 3–9: ethics, recruitment, randomization/blinding, gas administration, outcomes and statistical methods Pages 9–12: participant losses, Tables 1–2, primary QoR-15 result Pages 13–18: exploratory recovery domains, biomarkers, adverse events Pages 24–25: limitations and interpretation Pages 29–30: funding and competing interests
AI-assisted editorial review of the available main full text, 29 October 2026. Complete 30-page publisher accepted manuscript, labelled Article in Press; not the final typeset version.
The article reports registration ChiCTR2200066326 on 1 December 2022. External registry details have not been independently verified.
29 October 2026
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