A low perioperative fraction of inspired oxygen reduces the incidence of postoperative atelectasis in patients undergoing abdominal surgery under general anesthesia: A systematic review and meta-analysis

Abstract

Objective

To determine the relative risk of atelectasis after abdominal surgery associated with perioperative fraction of inspired oxygen.

Methods

Our meta-analysis was registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration number: CRD 42021270703). The PubMed, Cochrane Library, EMBASE, and Web of Science databases were searched for randomized controlled trials reporting the influence of perioperative fraction of inspired oxygen on the incidence of postoperative atelectasis in patients who had undergone abdominal surgery under general anesthesia. We used a random-effect model to calculate the relative risk of postoperative atelectasis. Subgroup analyses were performed according to age, ventilation strategy, surgical incision site, and surgery duration.

Results

Finally, we included 10 randomized controlled trials involving 3471 participants. Compared with the high fraction of inspired oxygen group (60%–100%), a reduced atelectasis incidence after abdominal surgery was observed in the low fraction of inspired oxygen group (20%–40%). Patients with an average age ≥60 years benefited more from a low fraction of inspired oxygen in terms of prevention of postoperative atelectasis compared with those with an average age <60 years (risk ratio: 1.47; 95% confidence interval: 1.14–1.90). Patients undergoing lower abdominal surgery benefited from a low perioperative fraction of inspired oxygen (risk ratio: 1.43; 95% confidence interval: 1.14–1.80).

Conclusions

A low perioperative fraction of inspired oxygen may decrease the risk of atelectasis after lower abdominal surgery performed under general anesthesia, especially in patients with an average age <60 years.

Keywords

Abdominal surgery general anesthesia oxygen postoperative atelectasis meta-analysis

Introduction

Atelectasis is a postoperative complication observed in the majority of patients who undergo surgery under general anesthesia (GA) and can persist for several months.^1–4 Surgical manipulations, especially during abdominal surgery, can move the diaphragm cranially and decrease pulmonary compliance, resulting in a high incidence of postoperative atelectasis.^5–8 Three mechanisms may contribute to atelectasis development: gas absorption, lung tissue compression, and surfactant deficiency.² Moreover, atelectasis is considered the leading cause of several postoperative complications, such as pneumonia and hypoxemia, which hamper patients’ recovery.^2,3

Various modalities have been proposed to ensure patient safety; among these, a high perioperative fraction of inspired oxygen (FiO₂) is considered a promising option.^2,9–14 A high-pitched beep of an oxygen saturation detector and elevated levels of oxygen saturation are desirable for clinicians. However, the existing high-quality evidence on the association between FiO₂ and postoperative atelectasis is inconsistent.^15–18 It remains debatable among clinicians whether a high perioperative FiO₂ helps prevent postoperative atelectasis in patients who have undergone abdominal surgery. A set of international expert panel-based consensus recommendations on practical measures to prevent postoperative pulmonary complications was issued in 2019, which recommends a perioperative FiO₂ ≤40%.¹⁹ In 2020, Li et al. found that compared with a high perioperative FiO₂, a low perioperative FiO₂ was not associated with a lower incidence of postoperative atelectasis in patients who had undergone abdominal surgery under GA.¹⁵ This contrasts the study results reported by Wei et al. who concluded that a high perioperative FiO₂ induced postoperative atelectasis in patients who had undergone abdominal surgery under GA.²⁰ A high perioperative FiO₂ could be considered acceptable because it improves the safety margin in the event of hypoxia and prolonged apnea.¹⁶ However, a high perioperative FiO₂ reportedly causes atelectasis due to gas absorption.^2,9,21

Therefore, a comprehensive evaluation of the existing evidence regarding the association between perioperative FiO₂ and postoperative atelectasis in patients who have undergone abdominal surgery is urgently needed. We aimed to extract data from randomized controlled trials (RCTs) regarding postoperative atelectasis in patients who had undergone abdominal surgery under GA to compare the effect of high versus low perioperative FiO₂ and provide evidence that can guide clinical practice.

Methods

This meta-analysis was registered with the International Prospective Register of Systematic Reviews (PROSPERO; registration number: CRD 42021270703). We conducted this systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.²² The PRISMA checklist is presented in Table S1.

Search strategies

The PubMed, Cochrane Library, EMBASE, and Web of Science databases were comprehensively searched for RCTs published before September 2025 that had investigated the influence of perioperative FiO₂ on the incidence of atelectasis after abdominal surgery. In addition, the bibliographies of all included studies were checked for any potential additional publications of interest. Searches were rerun immediately before the final analysis to identify any additional studies that meet the inclusion criteria. The detailed search strategies for each database are presented in Table S2.

Inclusion and exclusion criteria

The inclusion criteria were as follows: (a) RCTs; (b) studies investigating the influence of perioperative FiO₂ on the incidence of atelectasis after abdominal surgery; (c) surgeries were performed among adults (aged ≥18 years); and (d) full text of the article was available. A perioperative FiO₂ ≥50% was considered high and perioperative FiO₂ <50% low.

Studies were excluded if they were duplicate publications, reviews, editorials, abstracts, comments, case reports, meetings, or animal experiments. We also excluded studies wherein patients had undergone surgery under local anesthesia, had only received oxygen postoperatively or for a short duration intraoperatively, or had received supplemental oxygen during their stay in the intensive care unit.

Data extraction

Two reviewers (Z.W. and M.J.) independently screened the articles based on their titles and abstracts, according to our eligibility criteria; they also evaluated the risk of bias in the included studies using Cochrane Collaboration’s tool for assessing the risk of bias in RCTs. They extracted data from the included studies following a prespecified protocol; any disagreements were resolved via consultation. The original data included characteristics of the included studies (first author, country, publication year, sample size, and patient age), intervention strategies, and outcomes (incidence of postoperative atelectasis and severity of postoperative atelectasis). We used a widely accepted formula to estimate the mean and SD values using the data described in the form of median (interquartile range) values.²³ The severity of postoperative atelectasis was evaluated using Wilcox severity scoring and lung ultrasound scoring system.^24,25

Data synthesis

Data were analyzed using Review Manager (RevMan, version 5.4, Copenhagen, Nordic Cochrane Centre, the Cochrane Collaboration, 2014). Dichotomous variables were expressed as risk ratios (RRs) and 95% confidence intervals (CIs), while continuous variables were described as mean differences and 95% CIs. Cochran’s Q test and Higgins’ I² statistical test were used to assess the statistical heterogeneity of the pooled results. If 0% ≤ I² < 25%, the results showed no heterogeneity; if 25% ≤ I² < 50%, the results showed a low level of heterogeneity; if 50% ≤ I² < 75%, the results showed a medium level of heterogeneity; and if 75% ≤ I² ≤ 100%, the results showed a high level of heterogeneity. Subgroup analyses were performed based on risk factors that might contribute to postoperative atelectasis (ventilation strategy, oxygen administration strategy, age, surgery duration, and surgical incision site). In addition, a sensitivity analysis was performed to detect the sources of heterogeneity by excluding specific studies.

Results

Study selection

We identified 1676 studies; of these, 618 were duplicates, and 1029 were excluded based on their titles and abstracts. Thus, 29 full-text articles were further screened, of which 9 were excluded due to lack of outcomes and 12 were excluded for reporting on patients who had undergone non-abdominal surgery. Finally, 10 studies^{15,16,20,26–32} that met the inclusion criteria were included (Figure 1). The characteristics of the included studies are presented in Table 1.

Figure 1.

PRISMA flow diagram. PRISMA: Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Table 1.

Characteristics of the included studies.

Study	Country	Sample size (High FiO₂/Low FiO₂)	Age (years)		FiO₂	Intervention strategy	PEEP	Measurement	Anesthesia maintenance	Type of surgery		Surgical site	Surgery duration (min)		Duration of anesthesia (min)
			Age (years)										High FiO₂	Low FiO₂	High FiO₂	Low FiO₂
			High FiO₂	Low FiO₂									High FiO₂	Low FiO₂	High FiO₂	Low FiO₂
Lin et al. 2021²⁸	China	316/314	71.45 ± 3.85	71.39 ± 2.80	0.8/0.4	Intraoperative	No	By POD 7 using ultrasonography	IVA and IA	Elective + emergency	Laparoscopy	Upper and lower	188.2 ± 12.7	188.7 ± 8.6	224.4 ± 5.0	224.3 ± 5.2
Park et al. 2021¹⁶	South Korea	87/85	65 ± 23	66 ± 24	0.6/0.35	Intraoperative	5 cmH₂O	By POD 2 using ultrasonography	IVA and IA	Elective	Laparoscopy + laparotomy	Upper and lower	NA	NA	NA	NA
Li et al. 2020¹⁵	China	126/125	54 ± 14	53 ± 13	0.6/0.35	Intraoperative	6–8 cmH₂O	By POD 7 using X-ray or CT	IVA and IA	Elective	Laparoscopy + laparotomy	Upper and lower	196.7 ± 68.2	201.4 ± 84.0	257.1 ± 63.7	273.5 ± 85.5
Kim et al. 2020²⁹	South Korea	46/44	53 ± 14	51 ± 12	1.0/0.4	Intraoperative	5 cmH₂O	In PACU using ultrasonography	IVA	Elective	Laparoscopy	Lower	130.3 ± 72.7	103.5 ± 53.6	171.8 ± 88.0	150.3 ± 67.4
Ferrando et al. 2020³⁰	Multi-country study	362/355	64.2 ± 12.8	63.9 ± 13.9	0.8/0.3	Intraoperative and postoperative 3 h	Individualized PEEP	By POD 30 via radiography or CT	IVA and IA	Elective	Laparoscopy + laparotomy	Upper and lower	214.2 ± 93.3	209.2 ± 89.7	NA	NA
Alvandipour et al. 2019³¹	Iran	40/40	58.4 ± 8.1	59.2 ± 9.2	0.8/0.3	Intraoperative and postoperative 1 h	No	Before discharge via radiography or CT	IA	Elective	Laparotomy	Lower	NA	NA	NA	NA
Staehr et al. 2012³²	Denmark	20/15	64 ± 13	59 ± 16	0.8/0.3	Intraoperative and postoperative 2 h	5 cmH₂O	By POD 14 via radiography or CT	IVA and IA	Elective	Laparotomy	Lower	NA	NA	177.7 ± 110.1	202.2 ± 116.1
Meyhoff et al. 2009²⁶	Denmark	685/701	58 ± 43	60 ± 37	0.8/0.3	Intraoperative and postoperative 2 h	No	By POD 14 via radiography or CT	IVA and IA	Elective + emergency	Laparotomy	Upper and lower	160.2 ± 202.1	155.1 ± 193.1	221.5 ± 237.7	214.6 ± 219.9
Akça et al. 1999²⁷	Austria	16/14	49 ± 14	41 ± 10	0.8/0.3	Intraoperative and postoperative 2 h	No	By POD 1 via radiography or CT	IA	Elective	NA	Lower	198 ± 60	168 ± 60	NA	NA
Wei et al. 2025²⁰	China	40/40	63 ± 8	64 ± 7	0.6/0.27	Intraoperative	5 cmH₂O	In PACU using ultrasonography	IA	Elective	Laparoscopy	Upper and lower	180 ± 22	175 ± 15	210 ± 27	200 ± 20

PEEP: positive end-expiratory pressure; IVA: intravenous anesthesia; IA: inhalational anesthesia; FiO₂: fraction of inspired oxygen; POD: postoperative day; CT: computed tomography; PACU: post-anesthesia care unit.

Study quality and risk of bias

The risk of bias assessment is presented Figures 2 and S1. A high risk of performance bias was observed in four studies^16,27,28,30 because the anesthesiologists in these studies were not blinded to the trials; they were aware of the FiO₂ target for each participant and made proper adjustments to achieve the target FiO₂ levels. Three studies did not report whether the anesthesiologists assigned to perioperative management and the patients were aware of group assignment;^26,29,31; thus, these studies were rated as having an “unclear risk” of performance bias. The anesthesiologists in the other three studies were also not blinded to the trials; however, they were not involved in the studies.^15,20,32 Therefore, they were recorded as having a low risk of performance bias.

Figure 2.

Risk of bias summary. Green, yellow, and red represent low risk of bias, unclear bias, and high risk of bias, respectively.

Outcome

All 10 studies^{15,16,20,26–32} reported the incidence of postoperative atelectasis in patients who had undergone abdominal surgery under GA. The pooled results of the meta-analysis indicated that compared with a high perioperative FiO₂ (60%–100%), a low perioperative FiO₂ (≤40%) was associated with a significantly reduced incidence of atelectasis after abdominal surgery (RR: 1.43; 95% CI: 1.14–1.80; p = 0.002), with moderate heterogeneity (I² = 60%, p = 0.007) (Figure 3).

Figure 3.

Forest plot of the association between perioperative fraction of inspired oxygen and incidence of postoperative atelectasis.

Subgroup analyses

The use of positive end-expiratory pressure (PEEP) was reported in six studies.^{15,16,20,29,30,32} Patients in both high and low FiO₂ groups did not benefit from intraoperative PEEP application in terms of prevention of atelectasis after abdominal surgery (RR: 1.35; 95% CI: 1.01–1.82; p = 0.04), with moderate heterogeneity (I² = 56%, p = 0.04). The beneficial effect of a low perioperative FiO₂ in preventing atelectasis after abdominal surgery was statistically significant when PEEP was not applied intraoperatively (RR: 1.54; 95% CI: 1.03–2.30; p = 0.01), with moderate heterogeneity (I² = 68%, p = 0.02) (Figure 4).

Figure 4.

Subgroup analysis based on the application of positive end-expiratory pressure.

Four studies involved patients with an average age of ≥60 years,^16,20,28,30 other four studies involved patients with an average age <60 years,^15,27,29,31 and the rest two were awaiting further classification because they involved patients aged 58–64 years.^26,32 The incidence of postoperative atelectasis was significantly reduced by a low perioperative FiO₂ in the subgroup of participants aged <60 years (RR: 1.64; 95% CI: 1.31–2.06; p < 0.0001), with no heterogeneity (I² = 0%, p = 0.88). No significant difference was found in the subgroup of patients aged ≥60 years (RR: 1.35; 95% CI: 0.84–2.16; p = 0.22), with high heterogeneity (I² = 84%, p = 0.0003) (Figure 5).

Figure 5.

Subgroup analysis by age.

Oxygen was administered both intraoperatively and postoperatively in five studies,^{26,27,30–32} while the other five studies only exposed patients to oxygen during the surgery.^{15,16,20,28,29} As depicted in Figure 6, patients in the low FiO₂ group had a lower incidence of atelectasis after surgery when oxygen was only administered intraoperatively (RR: 1.66; 95% CI: 1.28–2.15; p = 0.0002), with moderate heterogeneity (I² = 60%, p = 0.04). No significant difference was observed between the high and low FiO₂ groups when oxygen was administered both intraoperatively and postoperatively (RR: 1.12; 95% CI: 0.86–1.47; p = 0.39), with low heterogeneity (I² = 14%, p = 0.32) (Figure 6).

Figure 6.

Subgroup analysis by oxygen administration strategies.

Four studies reported that patients who had undergone lower abdominal surgery benefited more from a low perioperative FiO₂ in terms of prevention of postoperative atelectasis (RR: 1.63; 95% CI: 1.27–2.08; p = 0.0001), with no heterogeneity (I² = 0%, p = 0.89)].^27,29,31,32 Six studies involved both patients undergoing upper abdominal surgery and lower abdominal surgery, and the incidence of postoperative atelectasis was comparable between the high and low FiO₂ groups (RR: 1.36; 95% CI: 0.97–1.89; p = 0.08), with high heterogeneity (I² = 77%, p = 0.0007)] (Figure 7).^{15,16,20,26,28,29}

Figure 7.

Subgroup analysis by surgical incision site.

Three studies reported a mean surgery duration of ≥3 h,^15,28,30 while a shorter mean surgery duration (<3 h) was observed in other three studies.^20,26,29 No significant difference was observed between the high FiO₂ and low FiO₂ groups in terms of postoperative atelectasis incidence (RR: 1.47; 95% CI: 0.78–2.77; p = 0.24) (Figure 8).

Figure 8.

Subgroup analysis by surgery duration.

Severity of postoperative atelectasis

Five studies reported the severity of postoperative atelectasis.^{16,20,27,29,32} However, owing to the inconsistent data format and a small sample size, we could not identify any clear data trends or detect important differences in the severity of postoperative atelectasis between the high and low FiO₂ groups.

Sensitivity analysis

The heterogeneity significantly decreased after excluding the studies by Lin et al. and Meyhoff et al. because both these studies involved patients undergoing emergency surgery, a risk factor for postoperative pulmonary complications (I² = 40%, p = 0.11) (Figure S2).^33,34

Discussion

Our meta-analysis of 10 RCTs suggested that a low perioperative FiO₂ (≤40%) significantly reduced the incidence of postoperative atelectasis in patients who had undergone abdominal surgery under GA, especially those aged <60 years and those undergoing lower abdominal surgery. PEEP did not help prevent atelectasis after abdominal surgery in either the high FiO₂ (60%–100%) or low FiO₂ (≤40%) group.

Three meta-analyses have reported the influence of different perioperative FiO₂ levels on postoperative pulmonary function.^17,18,35 However, they focused on patients undergoing different types of surgery; hence, the findings lacked specificity. In contrast, the conclusions about atelectasis were derived from results with high heterogeneity and very low-quality evidence, making them incapable of illustrating the influence of perioperative oxygen on atelectasis incidence.

To the best of our knowledge, this is the first systematic review and meta-analysis that focused on the influence of perioperative FiO₂ on postoperative atelectasis incidence in patients undergoing abdominal surgery under GA. Moreover, the comprehensive subgroup analyses according to the risk factors for pulmonary complications after abdominal surgery and sensitivity analyses can help evaluate the robustness of our results.

Our study suggested that a low perioperative FiO₂ (≤40%) is beneficial for preventing atelectasis after abdominal surgery. During clinical practice, concerns regarding the occurrence of hypoxemic events may prompt greater intraoperative oxygen administration. Moreover, a set of guidelines issued by World Health Organization in 2016 has recommended the maintenance of a high perioperative FiO₂ (80%) to improve patient prognosis.³⁶ Thus, we should weigh the advantages and disadvantages of high versus low perioperative FiO₂ levels.

Aging is strongly associated with a higher incidence of postoperative pulmonary complications.^7,8 The present study showed that patients with an average age ≥60 years did not exhibit the beneficial effects of perioperative low FiO₂ (≤40%) in terms of prevention of atelectasis after abdominal surgery. Age reflects the functional capacity of the body, and postoperative atelectasis results from target organ dysfunctions and poor physical condition of the patient.^7,37 Therefore, further studies should focus on preventing postoperative atelectasis in patients aged >60 years.

The beneficial effects of lung-protective ventilation strategies, including PEEP, have been widely accepted by clinicians.^38–40 However, the ideal level of PEEP during surgery has not yet been established. Our data showed that intraoperative PEEP application may reduce the beneficial effects of a low perioperative FiO₂ in preventing atelectasis after abdominal surgery, based on a result with moderate heterogeneity. Thus, further investigations on the ideal level of PEEP and an optimal perioperative FiO₂ level for prevention of postoperative atelectasis are urgently needed.

Filling the lungs with oxygen appears convincing, considering the difficulty in breathing and subsequent hypoxemia experienced after waking up. Our study suggested that only a low intraoperative FiO₂ was beneficial for preventing atelectasis after abdominal surgery. However, current evidence regarding the influence of post-oxygenation on postoperative atelectasis includes several confounders, such as the presence of lung-protective ventilation and lack of blank controls.^41–43 Therefore, the influence of post-oxygenation on postoperative atelectasis should be independently assessed in future studies.

Patients with lower abdominal surgical incision may experience a reduced incidence of postoperative atelectasis compared with those with an upper abdominal incision.⁸ In our study, patients with lower abdominal incision benefited from perioperative low FiO₂ (≤40%) in reducing the incidence of postoperative atelectasis. The upper abdominal incision is closer to the diaphragm than the lower abdominal incision; therefore, surgeries involving upper abdominal incision are more likely to cause cranial displacement of the diaphragm, and more remarkably, affect pulmonary function, resulting in a higher incidence of postoperative atelectasis.^5–8

To evaluate the influence of individual studies on the overall effect and identify the sources of heterogeneity, we performed a sensitivity analysis by excluding specific studies. After excluding a study involving patients undergoing emergency surgery, the heterogeneity decreased considerably (I² = 41%).²⁸ Notably, emergency surgery is a risk factor for postoperative pulmonary complications.^33,34

Certain limitations of our study should be acknowledged. First, the incidence of postoperative pulmonary complications gradually increased with prolonged surgery duration. The odds ratio may rise up to 9.7 (4.7–19.9) when the surgery lasts for >3 h.^7,8 However, the subgroup analysis by surgery duration in our study had a small sample size with high heterogeneity. Thus, further studies should focus on the association between surgery duration and the beneficial effects of perioperative low FiO₂ (≤40%) for the prevention of atelectasis after abdominal surgery. Second, the definitions of postoperative atelectasis varied among the included studies. Data were captured at different time points after surgery, which may be another factor contributing to the moderate heterogeneity.

Conclusions

Moderate-quality evidence from the present meta-analysis suggests that a low perioperative FiO₂ decreases the risk of postoperative atelectasis in patients undergoing lower abdominal surgery under GA, especially those with an average age <60 years.

Supplemental Material

sj-pdf-1-imr-10.1177_03000605251392431 - Supplemental material for A low perioperative fraction of inspired oxygen reduces the incidence of postoperative atelectasis in patients undergoing abdominal surgery under general anesthesia: A systematic review and meta-analysis

Supplemental material, sj-pdf-1-imr-10.1177_03000605251392431 for A low perioperative fraction of inspired oxygen reduces the incidence of postoperative atelectasis in patients undergoing abdominal surgery under general anesthesia: A systematic review and meta-analysis by Zuofeng Wang, Min Jiang, Cuiyuan Huang, Hengjing Zou, Yu Wen and Shan Ou in Journal of International Medical Research

Supplemental Material

sj-pdf-2-imr-10.1177_03000605251392431 - Supplemental material for A low perioperative fraction of inspired oxygen reduces the incidence of postoperative atelectasis in patients undergoing abdominal surgery under general anesthesia: A systematic review and meta-analysis

Supplemental material, sj-pdf-2-imr-10.1177_03000605251392431 for A low perioperative fraction of inspired oxygen reduces the incidence of postoperative atelectasis in patients undergoing abdominal surgery under general anesthesia: A systematic review and meta-analysis by Zuofeng Wang, Min Jiang, Cuiyuan Huang, Hengjing Zou, Yu Wen and Shan Ou in Journal of International Medical Research

Footnotes

Acknowledgements

This study would not have been possible without the collaboration of all colleagues in our team.

Authors’ contributions

Z.W. and S.O. designed this study. Z.W. and C.H. searched all the databases independently and screened the articles based on their titles and abstracts according to our eligibility criteria. Y.W. and H.Z. performed data analyses. Z.W. prepared the manuscript. S.O. supervised all study processes and revised the manuscript. All authors have read and approved the final manuscript.

Data availability statement

All data are available upon request to the corresponding authors.

Declaration of competing interest

We declare that there is no conflict of interest regarding this study.

Funding

This study did not receive any grant from funding agencies in the public, commercial, or not-for-profit sectors.

ORCID iD

Zuofeng Wang

Supplemental material

Supplemental material for this article is available online.

References

Gunnarsson

Tokics

Gustavsson

, et al. Influence of age on atelectasis formation and gas exchange impairment during general anaesthesia. Br J Anaesth 1991; 66: 423–432.

Duggan

Kavanagh

BP.

Pulmonary atelectasis: a pathogenic perioperative entity. Anesthesiology 2005; 102: 838–854.

Van Kaam

Lachmann

Herting

, et al. Reducing atelectasis attenuates bacterial growth and translocation in experimental pneumonia. Am J Respir Crit Care Med 2004; 169: 1046–1053.

Van Belle

Wesseling

Penn

, et al. Postoperative pulmonary function abnormalities after coronary artery bypass surgery. Resp Med 1992; 86: 195–199.

Strang

Freden

Maripuu

, et al. Improved ventilation-perfusion matching with increasing abdominal pressure during CO₂-pneumoperitoneum in pigs. Acta Anaesthesiol Scand 2011; 55: 887–896.

Andersson

Baath

Thorne

, et al. Effect of carbon dioxide pneumoperitoneum on development of atelectasis during anesthesia, examined by spiral computed tomography. Anesthesiology 2005; 102: 293–299.

Canet

Gallart

Gomar

; ARISCAT Groupet al. Prediction of postoperative pulmonary complications in a population-based surgical cohort. Anesthesiology 2010; 113: 1338–1350.

Brooks-Brunn

JA.

Predictors of postoperative pulmonary complications following abdominal surgery. Chest 1997; 111: 564–571.

Edmark

Kostova-Aherdan

Enlund

, et al. Optimal oxygen concentration during induction of general anesthesia. Anesthesiology 2003; 98: 28–33.

10.

Futier

Constantin

Pelosi

, et al. Intraoperative recruitment maneuver reverses detrimental pneumoperitoneum-induced respiratory effects in healthy weight and obese patients undergoing laparoscopy. Anesthesiology 2010; 113: 1310–1319.

11.

Park

Hwang

Kim

, et al. Effect of pre-emptive alveolar recruitment strategy before pneumoperitoneum on arterial oxygenation during laparoscopic hysterectomy. Anaesth Intensive Care 2009; 37: 593–597.

12.

Park

Jeon

Hwang

, et al. A preemptive alveolar recruitment strategy before one-lung ventilation improves arterial oxygenation in patients undergoing thoracic surgery: a prospective randomised study. Eur J Anaesthesiol 2011; 28: 298–302.

13.

Song

Jang

Lee

, et al. Effect of different fraction of inspired oxygen on development of atelectasis in mechanically ventilated children: a randomized controlled trial. Paediatr Anaesth 2019; 29: 1033–1039.

14.

Hedenstierna

Oxygen and anesthesia: what lung do we deliver to the post-operative ward?

Acta Anaesthesiol Scand 2012; 56: 675–685.

15.

Jiang

, et al. Comparison of low and high inspiratory oxygen fraction added to lung-protective ventilation on postoperative pulmonary complications after abdominal surgery: a randomized controlled trial. J Clin Anesth 2020; 67: 110009.

16.

Park

Jung

Sim

, et al. Perioperative high inspired oxygen fraction induces atelectasis in patients undergoing abdominal surgery: a randomized controlled trial. J Clin Anesth 2021; 72: 110285.

17.

Hovaguimian

Lysakowski

Elia

, et al. Effect of intraoperative high inspired oxygen fraction on surgical site infection, postoperative nausea and vomiting, and pulmonary function: systematic review and meta-analysis of randomized controlled trials. Anesthesiology 2013; 119: 303–316.

18.

Mattishent

Thavarajah

Sinha

, et al. Safety of 80% vs 30–35% fraction of inspired oxygen in patients undergoing surgery: a systematic review and meta-analysis. Br J Anaesth 2019; 122: 311–324.

19.

Young

Harris

Vacchiano

, et al. Lung-protective ventilation for the surgical patient: international expert panel-based consensus recommendations. Br J Anaesth 2019; 123: 898–913.

20.

Wei

Kang

Zhang

, et al. Individual FiO₂ guided by SPO₂ prevents hyperoxia and reduces postoperative atelectasis in colorectal surgery: a randomized controlled trial. J Clin Anesth 2025; 101: 111732.

21.

Rusca

Proietti

Schnyder

, et al. Prevention of atelectasis formation during induction of general anesthesia. Anesth Analg 2003; 97: 1835–1839.

22.

Moher

Liberati

Tetzlaff

; PRISMA Groupet al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 2009; 339: b2535.

23.

Wan

Wang

Liu

, et al. Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range. BMC Med Res Methodol 2014; 14: 135.

24.

Joyce

Baker

AB.

What is the role of absorption atelectasis in the genesis of perioperative pulmonary collapse?

Anaesth Intensive Care 1995; 23: 691–696.

25.

Monastesse

Girard

Massicotte

, et al. Lung ultrasonography for the assessment of perioperative atelectasis: a pilot feasibility study. Anesth Analg 2017; 124: 494–504.

26.

Meyhoff

Wetterslev

Jorgensen

; PROXI Trial Groupet al. Effect of high perioperative oxygen fraction on surgical site infection and pulmonary complications after abdominal surgery: the PROXI randomized clinical trial. JAMA 2009; 302: 1543–1550.

27.

Akça

Podolsky

Eisenhuber

, et al. Comparable postoperative pulmonary atelectasis in patients given 30% or 80% oxygen during and 2 hours after colon resection. Anesthesiology 1999; 91: 991–998.

28.

Lin

Wang

Liu

, et al. Intraoperative oxygen concentration and postoperative delirium after laparoscopic gastric and colorectal malignancies surgery: a randomized, double-blind, controlled trial. Clin Interv Aging 2021; 16: 1085–1093.

29.

Kim

Lee

Bae

, et al. Lung ultrasound score to determine the effect of fraction inspired oxygen during alveolar recruitment on absorption atelectasis in laparoscopic surgery: a randomized controlled trial. BMC Anesthesiol 2020; 20: 173.

30.

Ferrando

Aldecoa

Unzueta

; iPROVE-O2 Networket al. Effects of oxygen on post-surgical infections during an individualised perioperative open-lung ventilatory strategy: a randomised controlled trial. Br J Anaesth 2020; 124: 110–120.

31.

Alvandipour

Mokhtari-Esbuie

Baradari

, et al. Effect of hyperoxygenation during surgery on surgical site infection in colorectal surgery. Ann Coloproctol 2019; 35: 9–14.

32.

Staehr

Meyhoff

Henneberg

, et al. Influence of perioperative oxygen fraction on pulmonary function after abdominal surgery: a randomized controlled trial. BMC Res Notes 2012; 5: 383.

33.

Lukannek

Shaefi

Platzbecker

, et al. The development and validation of the score for the prediction of postoperative respiratory complications (SPORC-2) to predict the requirement for early postoperative tracheal re-intubation: a hospital registry study. Anaesthesia 2019; 74: 1165–1174.

34.

Yang

Zhou

, et al. Risk factors for predicting postoperative complications after open infrarenal abdominal aortic aneurysm repair: results from a single vascular center in China. J Clin Anesth 2013; 25: 371–378.

35.

Koo

Park

Lee

, et al. The effects of intraoperative inspired oxygen fraction on postoperative pulmonary parameters in patients with general anesthesia: a systemic review and meta-analysis. J Clin Med 2019; 8: 583.

36.

Allegranzi

Zayed

Bischoff

; WHO Guidelines Development Groupet al. New WHO recommendations on intraoperative and postoperative measures for surgical site infection prevention: an evidence-based global perspective. Lancet Infect Dis 2016; 16: e288–e303.

37.

Neto

Da Costa

LGV

Hemmes

SNT

; LAS VEGASet al. The LAS VEGAS risk score for prediction of postoperative pulmonary complications: an observational study. Eur J Anaesthesiol 2018; 35: 691–701.

38.

Futier

Constantin

Paugam-Burtz

; IMPROVE Study Groupet al. A trial of intraoperative low-tidal-volume ventilation in abdominal surgery. N Engl J Med 2013; 369: 428–437.

39.

Hemmes

Serpa Neto

Schultz

MJ.

Intraoperative ventilatory strategies to prevent postoperative pulmonary complications: a meta-analysis. Curr Opin Anaesthesiol 2013; 26: 126–133.

40.

Wang

Liu

Effect of lung-protective ventilation with lower tidal volumes on clinical outcomes among patients undergoing surgery: a meta-analysis of randomized controlled trials. CMAJ 2015; 187: E101–E109.

41.

Benoit

Wicky

Fischer

, et al. The effect of increased FIO(2) before tracheal extubation on postoperative atelectasis. Anesth Analg 2002; 95: 1777–1781.

42.

Lumb

Greenhill

Simpson

, et al. Lung recruitment and positive airway pressure before extubation does not improve oxygenation in the post-anaesthesia care unit: a randomized clinical trial. Br J Anaesth 2010; 104: 643–647.

43.

Futier

Paugam-Burtz

Godet

; OPERA study investigatorset al. Effect of early postextubation high-flow nasal cannula vs conventional oxygen therapy on hypoxaemia in patients after major abdominal surgery: a French multicentre randomised controlled trial (OPERA). Intensive Care Med 2016; 42: 1888–1898.

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