Comparison of low and high inspiratory oxygen fraction added to lung-protective ventilation on postoperative pulmonary complications after abdominal surgery: A randomized controlled trial

Association between mechanical power during one-lung ventilation and pulmonary complications after thoracoscopic lung resection surgery: a prospective observational study

BACKGROUND

The role of mechanical power on pulmonary outcomes after thoracic surgery with one-lung ventilation was unclear. We investigated the association between mechanical power and postoperative pulmonary complications in patients undergoing thoracoscopic lung resection surgery.

METHODS

In this single-center, prospective observational study, 622 patients scheduled for thoracoscopic lung resection surgery were included. Volume control mode with lung protective ventilation strategies were implemented in all participants. The primary endpoint was a composite of postoperative pulmonary complications during hospital stay. Multivariable logistic regression models were used to evaluate the association between mechanical power and outcomes.

RESULTS

The incidence of pulmonary complications after surgery during hospital stay was 24.6% (150 of 609 patients). The multivariable analysis showed that there was no link between mechanical power and postoperative pulmonary complications.

CONCLUSIONS

In patients undergoing thoracoscopic lung resection with standardized lung-protective ventilation, no association was found between mechanical power and postoperative pulmonary complications.

TRIAL REGISTRATION

Trial registration number: ChiCTR2200058528, date of registration: April 10, 2022.

Effect of Volatile Anesthesia Versus Intravenous Anesthesia on Postoperative Pulmonary Complications in Patients Undergoing Minimally Invasive Esophagectomy: A Randomized Clinical Trial

BACKGROUND

The effect of intraoperative anesthetic regimen on pulmonary outcome after minimally invasive esophagectomy for esophageal cancer is yet undetermined. The aim of this study was to determine the effect of volatile anesthesia (sevoflurane or desflurane) compared with propofol-based intravenous anesthesia on pulmonary complications after minimally invasive esophagectomy.

METHODS

Patients scheduled for minimally invasive esophagectomy were randomly assigned to 1 of 3 general anesthetic regimens (sevoflurane, desflurane, or propofol). The primary outcome was the incidence of pulmonary complications within the 7 days postoperatively, which was a collapsed composite end point, including respiratory infection, pleural effusion, pneumothorax, atelectasis, respiratory failure, bronchospasm, pulmonary embolism, and aspiration pneumonitis. The severity of pulmonary complications, surgery-related complications, and other secondary outcomes were also assessed.

RESULTS

Of 647 patients assessed for eligibility, 558 were randomized, and 553 were analyzed. A total of 185 patients were assigned to the sevoflurane group, 185 in the desflurane, and 183 in the propofol group. Patients receiving a volatile anesthetic (sevoflurane or desflurane) had a significantly lower incidence (36.5% vs 47.5%; odds ratio, 0.63; 95% confidence interval, 0.44-0.91; P = .013) and lower severity grade of pulmonary complications (P = .035) compared to the patients receiving propofol. There were no statistically significant differences in other secondary outcomes between the 2 groups.

CONCLUSIONS

In patients undergoing minimally invasive esophagectomy, the use of volatile anesthesia (sevoflurane or desflurane) resulted in the reduced risk and severity of pulmonary complications within the first 7 postoperative days as compared to propofol-based intravenous anesthesia.

The incidence, risk factors and outcomes of impaired cerebral autoregulation in aortic arch surgery: a single-center, retrospective cohort study

BACKGROUND

Impairment of cerebral autoregulation (CA) has been observed in patients undergoing cardiopulmonary bypass (CPB), but little is known about its risks and associations with outcomes. The cerebral oximetry index (COx), which is a moving linear correlation coefficient between regional cerebral oxygen saturation (rScO2) and mean blood pressure (MAP), may reflect CA function. When COx approaches 1, it implies that CA is damaged, whereas the CA is functional when the COx value approaches 0. The objective of this study was to analyze the incidence and risks of impaired CA, based on COx assessment, in patients undergoing total aortic arch replacement under systemic moderate hypothermia and circulatory arrest of the lower body (MHCA). We also evaluated the association between impaired CA and patient outcomes.

METHODS

One hundred and fifty-four adult patients who underwent total aortic arch replacement with stented elephant trunk implantation under MHCA at our hospital were retrospectively analyzed. Patients were defined as having new-onset impaired CA if pre-CPB COx < 0.3 and post-CPB COx > 0.3. Pre- and intraoperative factors were tested for independent association with impaired CA. Postoperative outcomes were compared between patients with normal and impaired CA.

RESULTS

In our 154 patients, 46(29.9%) developed new-onset impaired CA after CPB. Multivariable analysis revealed a prolonged low rScO2 (rScO2 < 55%) independently associated with onset of impaired CA, and receiver operating charactoristic curve showed a cutoff value at 40 min (sensitivity, 89.5%; specificity, 68.0%). Compared with normal CA patients, those with impaired CA showed a significantly higher rates of in-hospital mortality and postoperative complications.

CONCLUSIONS

Prolonged low rScO2 (rScO2 < 55%) during aortic arch surgery was closely related to onset of impaired CA. Impaired CA remained associated with the increased rates of postoperative complications and in-hospital mortality.

TRIAL REGISTRATION

ChiCTR1800014545 with registered date 20/01/2018.

The effect of high perioperative inspiratory oxygen fraction for abdominal surgery on surgical site infection: a systematic review and meta-analysis

Guidelines from the World Health Organization strongly recommend the use of a high fraction of inspired oxygen (FiO2) in adult patients undergoing general anesthesia to reduce surgical site infection (SSI). However, previous meta-analyses reported inconsistent results. We aimed to address this controversy by focusing specifically on abdominal surgery with relatively high risk of SSI. Medline, EMBASE, and Cochrane CENTRAL databases were searched. Randomized trials of abdominal surgery comparing high to low perioperative FiO2 were included, given that the incidence of SSI was reported as an outcome. Meta-analyses of risk ratios (RR) were performed using a fixed effects model. Subgroup analysis and meta-regression were employed to explore sources of heterogeneity. We included 27 trials involving 15977 patients. The use of high FiO2 significantly reduced the incidence of SSI (n = 27, risk ratio (RR): 0.87; 95% confidence interval (CI): 0.79, 0.95; I2 = 49%, Z = 3.05). Trial sequential analysis (TSA) revealed that z-curve crossed the trial sequential boundary and data are sufficient. This finding held true for the subgroup of emergency operations (n = 2, RR: 0.54; 95% CI: 0.35, 0.84; I2 = 0%, Z = 2.75), procedures using air as carrier gas (n = 9, RR: 0.79; 95% CI: 0.69, 0.91; I2 = 60%, Z = 3.26), and when a high level of FiO2 was maintained for a postoperative 6 h or more (n = 9, RR: 0.68; 95% CI: 0.56, 0.83; I2 = 46%, Z = 3.83). Meta-regression revealed no significant interaction between SSI with any covariates including age, sex, body-mass index, diabetes mellitus, duration of surgery, and smoking. Quality of evidence was assessed to be moderate to very low. Our pooled analysis revealed that the application of high FiO2 reduced the incidence of SSI after abdominal operations. Although TSA demonstrated sufficient data and cumulative analysis crossed the TSA boundary, our results should be interpreted cautiously given the low quality of evidence.Registration: https://www.crd.york.ac.uk/prospero (CRD42022369212) on October 2022.

Effect of permissive hypercarbia on lung oxygenation during one-lung ventilation and postoperative pulmonary complications in patients undergoing thoracic surgery: A prospective randomised controlled trial

BACKGROUND

The effect of hypercarbia on lung oxygenation during thoracic surgery remains unclear.

OBJECTIVE

To investigate the effect of hypercarbia on lung oxygenation during one-lung ventilation in patients undergoing thoracic surgery and evaluate the incidence of postoperative pulmonary complications.

DESIGN

Prospective randomised controlled trial.

SETTING

A tertiary university hospital in the Republic of Korea from November 2019 to December 2020.

PATIENTS

Two hundred and ninety-seven patients with American Society of Anaesthesiologists physical status II to III, scheduled to undergo elective lung resection surgery.

INTERVENTION

Patients were randomly assigned to Group 40, 50, or 60. An autoflow ventilation mode with a lung protective ventilation strategy was applied to all patients. Respiratory rate was adjusted to maintain a partial pressure of arterial carbon dioxide of 40 ± 5 mmHg in Group 40, 50 ± 5 mmHg in Group 50 and 60 ± 5 mmHg in Group 60 during one-lung ventilation and at the end of surgery.

MAIN OUTCOME MEASURES

The primary outcome was the arterial oxygen partial pressure/fractional inspired oxygen ratio after 60 min of one-lung ventilation.

RESULTS

Data from 262 patients were analysed. The partial pressure/fractional inspired oxygen ratio was significantly higher in Group 50 and Group 60 than in Group 40 (269.4 vs. 262.9 vs. 214.4; P  < 0.001) but was not significantly different between Group 50 and Group 60. The incidence of postoperative pulmonary complications was comparable among the three groups.

CONCLUSION

Permissive hypercarbia improved lung oxygenation during one-lung ventilation without increasing the risk of postoperative pulmonary complications or the length of hospital stay.

TRIAL REGISTRATION

NCT04175379.

Effects of 30% vs. 60% inspired oxygen fraction during mechanical ventilation on postoperative atelectasis: a randomised controlled trial

BACKGROUND

There is the ongoing debate over the effect of inspired oxygen fraction (FiO2) during mechanical ventilation on postoperative atelectasis. We aimed to compare the effects of low (30%) and moderate (60%) FiO2 on postoperative atelectasis. The hypothesis of the study was that 30% FiO2 during mechanical ventilation could reduce postoperative atelectasis volume compared with 60% FiO2.

METHODS

We performed a randomized controlled trial with 120 patients. Subjects were randomly assigned to receive 30% or 60% FiO2 during mechanical ventilation in a 1:1 ratio. The primary outcome was the percentage of postoperative atelectasis volume in the total lung measured using chest CT within 30 min after extubation. The secondary outcomes included different aeration region volumes, incidence of clinically significant atelectasis, and oxygenation index.

RESULTS

In total, 113 subjects completed the trial, including 55 and 58 subjects in the 30% and 60% FiO2 groups, respectively. The percentage of the postoperative atelectasis volume in the 30% FiO2 group did not differ from that in the 60% FiO2 group. Furthermore, there was no significant difference in the atelectasis volume between the two groups after the missing data were imputed by multiple imputation. Additionally, there were no significant differences in the volumes of the over-aeration, normal-aeration, and poor-aeration regions between the groups. No significant differences in the incidence of clinically significant atelectasis or oxygenation index at the end of surgery were observed between the groups.

CONCLUSIONS

Compared with 60% FiO2, the use of 30% FiO2 during mechanical ventilation does not reduce the postoperative atelectasis volume.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ( http://www.chictr.org.cn ). Identifier: ChiCTR1900021635. Date: 2 March 2019. Principal invetigator: Weidong Gu.

Effectiveness of oncology nurse navigator on the incidence of postoperative pulmonary complications in gastric cancer patients undergoing radical gastrectomy

BACKGROUND

Management of postoperative pulmonary complications (PPCs) can be challenging in gastric cancer patients undergoing radical gastrectomy and is always associated with poor prognosis. Even though oncology nurse navigator (ONN) provide effective and critical individualized care to patients, little is known about their impact on the occurrence of PPCs in gastric cancer patients. This study aimed to determine whether ONN decreases the incidence of PPCs in gastric cancer patients.

METHODS

This was a retrospective review in which data for gastric cancer patients at one centre was evaluated before and after an ONN hired. An ONN was introduced to patients at their initial visit to manage pulmonary complications throughout treatment. The research was conducted from 1 August 2020 to 31 January 2022. The study participants were divided into the non-ONN group (from 1 August 2020 to 31 January 2021) and the ONN group (from 1 August 2021 to 31 January 2022). The incidence and severity of PPCs between the groups were then compared.

RESULTS

ONN significantly decreased the incidence of PPCs (15.0% vs. 9.8%) (OR = 2.532(95% CI: 1.087-3.378, P = 0.045)), but there was no significant difference in the components of PPCs including pleural effusion, atelectasis, respiratory infection, and pneumothorax. The severity of PPCs was also significantly higher in the non-ONN group (p = 0.020). No significant statistical difference was observed for the major pulmonary complications ([Formula: see text] 3) between the two groups (p = 0.286).

CONCLUSIONS

Role of ONN significantly decrease the incidence of PPCs in gastric cancer patients undergoing radical gastrectomy.

The role of prophylactic administration of CPAP in general surgical wards after open visceral surgery in reducing postoperative pneumonia-a retrospective cohort study

BACKGROUND

Postoperative pneumonia is a main adverse event that causes increased postoperative morbidity and prolonged length of hospital stay leading to high postoperative mortality. Continuous positive airway pressure (CPAP) is a type of non-invasive ventilation for the delivery of a positive airway pressure during respiration. In this study, we evaluated the impact of postoperative prophylactic CPAP on prevention of pneumonia in patients after open visceral surgery.

METHODS

In this observational cohort study, we compared the rates of postoperative pneumonia in patients who underwent open major visceral surgery from January 2018 till August 2020 in the study and control group. The study group had postoperative prophylactic sessions of CPAP for 15 min, 3-5 times a day and a repeated spirometer training was also performed in the general surgical ward. The control group received only the postoperative spirometer training as a prophylactic measure against postoperative pneumonia. The chi-square test was used to measure the relationships between categorical variables, and a binary regression analysis determined the correlation between independent and dependent variables.

RESULTS

A total of 258 patients met the inclusion criteria who had open visceral surgery for various clinical illnesses. There were 146 men (56.6%) and 112 women with a mean age of 68.62 years. As many as 142 patients received prophylactic CPAP and they were grouped into the study group, whereas 116 patients without prophylactic CPAP were placed in the control group. Overall, the rate of postoperative pneumonia was significantly less in the study group (5.6% vs. 25.9% in the control group; p-value < 0.0001), which could be confirmed by the regression analysis (OR 0.118, CI 95% 0.047-0.295, p < 0.001).

CONCLUSION

Postoperative intermittent CPAP after open visceral surgery can be performed in a general surgical ward. Our study showed a significant association with a low rate of postoperative pneumonia, especially in high-risk patients. This leads to a significantly shorter postoperative hospital stay especially in high-risk patients after upper gastrointestinal surgery.

TRIAL REGISTRATION NUMBER

DRKS00028988, 04.05.2022, retrospectively registered.

Updated meta-analysis on intraoperative inspired fraction of oxygen and the risk of surgical site infection in adults undergoing general and regional anesthesia

This updated meta-analysis aims at exploring whether the use of systematic high vs low intraoperative oxygen fraction (FiO2) may decrease the incidence of postoperative surgical site infection during general (GA) or regional anesthesia (RA). PubMed, Cochrane CENTRAL, ClinicalTrials.gov databases were searched from January 1st, 1999 and July, 1st 2022, for randomized and quasi-randomized controlled trials that included patients in a high and low FiO2 groups and reported the incidence of SSI. The meta-analysis was conducted with a DerSimonian and Laird random-effects model. Thirty studies (24 for GA and 6 for RA) totaling 18,055 patients (15,871 for GA and 2184 for RA) were included. We have low-to-moderate-quality evidence that high FiO2 (mainly 80%) was not associated with a reduction of SSI incidence compared to low FiO2 (mainly 30%) in all patients (RR 0.90, 95%CI 0.79-1.03). Moderate inconsistency existed between studies (I2 = 38%). Subgroup analyses showed a moderate protective effect in patients undergoing GA (RR 0.86, 95%CI 0.75-0.99) (low level of evidence), while high FiO2 was not associated with a reduction of SSI in patients undergoing RA (RR 1.17, 95%CI 0.90-1.52) (moderate level of evidence). Sensitivity analyses restricted to patients ventilated without nitrous oxide (n = 20 studies), to patients operated from abdominal surgeries (n = 21 studies), and to patients suffering from deep SSI (n = 13 studies), all showed the absence of any significant effect of high FiO2. As a conclusion there is no compelling evidence that high FiO2 can improve postoperative patient's outcome on its own when good SSI prevention practices are properly applied. Recent well-designed and adequately powered randomized controlled trials add further weight to these results.

The effects of laryngeal mask airway versus endotracheal tube on atelectasis in patients undergoing general anesthesia assessed by lung ultrasound: A protocol for a prospective, randomized controlled trial

Background

The incidence of atelectasis is high in patients undergoing general anesthesia. This may cause oxygenation impairment and further contribute to postoperative pulmonary complications (PPCs). As important airway management devices for general anesthesia, few studies have compared the effects of laryngeal mask airway (LMA) and endotracheal tube (ETT) on atelectasis. Additionally, lung ultrasound has been increasingly used for bedside atelectasis diagnosis. For the above considerations, this trial is designed to compare the effects of LMA and ETT on atelectasis assessed by lung ultrasound scores, further providing more powerful clinical evidence for perioperative respiratory management of non-laparoscopic elective lower abdominal surgery under general anesthesia.

Methods

This is a prospective, single-center, single-blind, randomized controlled trial. From July 2021 to July 2022, 180 patients undergoing elective non-laparoscopic lower abdominal surgery under general anesthesia will be recruited and randomly divided into the ETT and LMA groups at a ratio of 1:1. The primary outcome is the total atelectasis LUS of 12 lung regions 15 min after the establishment of the artificial airway. The total atelectasis LUS at the end of surgery and 30 min after extubation, oxygenation index, postoperative airway complications, PPCs, and length of stay will be analyzed as secondary indicators.

Trial registration

ClinicalTrials.gov identifier: ChiCTR1900020818. Registered on January 20, 2019. Registered with the name of “Laryngeal mask airway versus endotracheal tube for atelectasis.” URL: https://www.chictr.org.cn/showproj.aspx?proj=35143.

Intraoperative Respiratory and Hemodynamic Strategies for Reducing Nausea, Vomiting, and Pain after Surgery: Systematic Review and Meta-Analysis

BACKGROUND

Despite improved medical treatment strategies, post-operative pain, nausea, and vomiting remain major challenges. This systematic review investigated the relationship between perioperative respiratory and hemodynamic interventions and postoperative pain, nausea, and vomiting.

METHODS

PubMed and Embase were searched on March 8, 2021 for randomized clinical trials investigating the effect of perioperative respiratory or hemodynamic interventions in adults undergoing non-cardiac surgery. Investigators reviewed trials for relevance, extracted data, and assessed risk of bias. Meta-analyses were performed when feasible. GRADE was used to assess the certainty in the evidence.

RESULTS

This review included 65 original trials; of these 48% had pain, nausea and/or vomiting as the primary focus. No reduction of postoperative pain was found in meta-analyses when comparing recruitment maneuvers with no recruitment, high (80%) to low (30%) fraction of oxygen, low (5-7 ml/kg) to high (9-12 ml/kg) tidal volume, or goal-directed hemodynamic therapy to standard care. In the meta-analysis comparing recruitment maneuvers with no recruitment maneuvers, patients undergoing laparoscopic gynecological surgery had less shoulder pain 24 hours postoperatively (mean difference in the numeric rating scale from 0 to 10: -1.1, 95% CI: -1.7, -0.5). In meta-analyses, comparing high to low fraction of inspired oxygen and goal-directed hemodynamic therapy to standard care in patients undergoing abdominal surgery, the risk of postoperative nausea and vomiting was reduced (odds ratio: 0.45, 95% CI: 0.24, 0.87 and 0.48, 95% CI: 0.27, 0.85). The certainty in the evidence was mostly very low to low. The results should be considered exploratory given the lack of pre-specified hypotheses and corresponding risk of Type 1 errors.

CONCLUSION

There is limited evidence regarding the impact of intraoperative respiratory and hemodynamic interventions on postoperative pain or nausea and vomiting. More definitive trials are needed to guide clinical care within this area. This article is protected by copyright. All rights reserved.

Effect of positioning and expiratory rib-cage compression on atelectasis in a patient who required prolonged mechanical ventilation: a case report

BACKGROUND

Pulmonary complications can be caused by intraoperative mechanical ventilation. In particular, prolonged mechanical ventilation is associated with a high mortality rate, a risk of pulmonary complications, prolonged hospitalization, and an unfavorable discharge destination. Pre- and postoperative rehabilitation are important for the resolution of pulmonary complications in acute cases. However, there has been a lack of studies on interventions for pulmonary rehabilitation of patients with chronic pulmonary complications caused by prolonged mechanical ventilation. Accordingly, we describe the effect of pulmonary rehabilitation in such a patient.

CASE PRESENTATION

We examined a 63-year-old Japanese woman with hypoxic-ischemic encephalopathy after subarachnoid hemorrhage who required prolonged mechanical ventilation. Radiographic and computed tomographic images revealed atelectasis of the right upper lobe. In addition, this atelectasis reduced the tidal volume, minute volume, and oxygen saturation and caused an absence of breath sounds in the right upper lobe during auscultation. We aimed to ameliorate the patient's atelectasis and improve her ventilation parameters by using positioning and expiratory rib-cage compression after endotracheal suctioning. Specifically, the patient was seated in Fowler's position, and mild pressure was applied to the upper thorax during expiration, improving her inspiratory volume. Immediately, breath sounds were audible in the right upper lobe. Furthermore, resolution of the patient's atelectasis was confirmed with chest radiography performed on the same day. In addition, her ventilation parameters (tidal volume, minute volume, and oxygen saturation) improved.

CONCLUSIONS

Our results indicate that physical therapists should consider application of specific positioning and expiratory rib-cage compression in patients who exhibit atelectasis because of prolonged mechanical ventilation.

Positive end-expiratory pressure and risk of postoperative pulmonary complications in patients living at high altitudes and undergoing surgery at low altitudes: a single-centre, retrospective observational study in China

OBJECTIVES

To examine whether a high positive end-expiratory pressure (PEEP ≥5 cmH₂O) has a protective effect on the risk of postoperative pulmonary complications (PPCs) in a cohort of patients living at high altitudes and undergoing general anaesthesia.

DESIGN

Retrospective, observational study.

SETTING

A tertiary hospital in China.

PARTICIPANTS

Adult Tibetan patients living at high altitudes (≥3000 m) and who went to the low-altitude plain to undergo non-cardiothoracic surgery under general anaesthesia, from January 2018 to April 2020.

MEASUREMENTS

This study included 1905 patients who were divided according to the application of an intraoperative PEEP: low PEEP (<5 cmH₂O, including 0 cmH₂O) or high PEEP (≥5 cmH₂O). The primary outcome was a composite of PPCs within the first 7 postoperative days. The secondary outcomes included reintubation and unplanned intensive care unit (ICU) admission within the first 7 postoperative days and total hospital stays (day).

RESULTS

The study included 1032 patients in the low PEEP group and 873 in the high PEEP group. There were no differences in the incidence of PPCs between the high and low PEEP groups (relative risk (RR) 0.913; 95% CI 0.716 to 1.165; p=0.465). After propensity score matching, 643 patients remained in each group, and the incidence of PPCs in the low PEEP group (18.0%) was higher than in the high PEEP group (13.7%; RR 0.720; 95% CI 0.533 to 0.974; p=0.033). There were no differences in the incidence of reintubation, unplanned ICU admission or hospital stays. The risk factors of PPCs derived from multiple regression showed that the application of >5 cmH₂O PEEP during intraoperative mechanical ventilation was associated with a significantly lower risk of PPCs in patients from a high altitude (OR=0.725, 95% CI 0.530 to 0.992; p=0.044).

CONCLUSIONS

The application of PEEP ≥5 cmH₂O during intraoperative mechanical ventilation in patients living at high altitudes and undergoing surgery at low altitudes may be associated with a lower risk of PPCs. Prospective longitudinal studies are needed to further investigate perioperative lung protection ventilation strategies for patients from high altitudes.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2100044260).

Fraction of Inspired Oxygen During General Anesthesia for Non-Cardiac Surgery: Systematic Review and Meta-Analysis

Background

Controversy exists regarding the effects of a high versus a low intraoperative fraction of inspired oxygen (FiO₂) in adults undergoing general anesthesia. This systematic review and meta‐analysis investigated the effect of a high versus a low FiO₂ on postoperative outcomes.

Methods

PubMed and Embase were searched on March 22, 2022 for randomized clinical trials investigating the effect of different FiO₂ levels in adults undergoing general anesthesia for non‐cardiac surgery. Two investigators independently reviewed studies for relevance, extracted data, and assessed risk of bias. Meta‐analyses were performed for relevant outcomes, and potential effect measure modification was assessed in subgroup analyses and meta‐regression. The evidence certainty was evaluated using GRADE.

Results

This review included 25 original trials investigating the effect of a high (mostly 80%) versus a low (mostly 30%) FiO₂. Risk of bias was intermediate for all trials. A high FiO₂ did not result in a significant reduction in surgical site infections (OR: 0.91, 95% CI 0.81–1.02 [p = .10]). No effect was found for all other included outcomes, including mortality (OR = 1.27, 95% CI: 0.90–1.79 [p = .18]) and hospital length of stay (mean difference = 0.03 days, 95% CI −0.25 to 0.30 [p = .84). Results from subgroup analyses and meta‐regression did not identify any clear effect modifiers across outcomes. The certainty of evidence (GRADE) was rated as low for most outcomes.

Conclusions

In adults undergoing general anesthesia for non‐cardiac surgery, a high FiO₂ did not improve outcomes including surgical site infections, length of stay, or mortality. However, the certainty of the evidence was assessed as low.

The efficacy of different alveolar recruitment maneuvers in holmium laser lithotripsy surgery under general anesthesia using a laryngeal mask

Background

Alveolar recruitment maneuvers (ARMs) is an important part of lung-protective ventilation strategies (LPVSs), but the optimal duration and interval Remain unclear.

Methods

Patients:252 patients who underwent holmium laser lithotripsy surgery and meet inclusion criteria were included and randomized into three groups based on the duration and frequency of ARMs (Regular, one 30 s ARM (RARMs); Improved and intermittent, three 10s ARMs (IARMs); and Control (C), no ARMs).Interventions: Groups R and I received ARMs at 20 cmH2O pressures every 30 min. All patients received the same anesthesia and mechanical ventilation. Measurements:Outcomes included heart rate and mean arterial pressure changes during ARMs and postoperative pulmonary complications (PPCs) within the first 7 postoperative days.

Main results

Incidences of PPCs in groups R(7.1%) and I (5.0%)were slightly lower than those in group C (8.9%).This indicated the potential to reduce lung injury. Heart rate and mean arterial pressure fluctuations during ARMs were significantly higher in groups R and I than in group C (P < 0.01). The rate of blood pressure decrease was significantly higher in group R than in group I (P < 0.01).

Conclusions

IARMs can reduce cycle fluctuations than RARMs in patients Undergoing holmium laser lithotripsy surgery with laryngeal mask general anesthesia. Low tidal volume ventilation and low PEEP combined with ARM did not significantly reduce the incidence of PPCs in healthy lung patients, but tended to reduce lung injury.

Trial registration

The study was registered on the Chinese Clinical Trial Registry.

(ChiCTR2000030815,15/03/2020). This study was approved by the ethics committee of Chengdu Fifth People’s Hospital with approval number(2020–005(Study)-1).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12871-022-01664-y.

Development and validation of a nomogram to predict postoperative pulmonary complications following thoracoscopic surgery

Background

Postoperative pulmonary complications (PPCs) after thoracoscopic surgery are common. This retrospective study aimed to develop a nomogram to predict PPCs in thoracoscopic surgery.

Methods

A total of 905 patients who underwent thoracoscopy were randomly enrolled and divided into a training cohort and a validation cohort at 80%:20%. The training cohort was used to develop a nomogram model, and the validation cohort was used to validate the model. Univariate and multivariable logistic regression were applied to screen risk factors for PPCs, and the nomogram was incorporated in the training cohort. The discriminative ability and calibration of the nomogram for predicting PPCs were assessed using C-indices and calibration plots.

Results

Among the patients, 207 (22.87%) presented PPCs, including 166 cases in the training cohort and 41 cases in the validation cohort. Using backward stepwise selection of clinically important variables with the Akaike information criterion (AIC) in the training cohort, the following seven variables were incorporated for predicting PPCs: American Society of Anesthesiologists (ASA) grade III/IV, operation time longer than 180 min, one-lung ventilation time longer than 60 min, and history of stroke, heart disease, chronic obstructive pulmonary disease (COPD) and smoking. With incorporation of these factors, the nomogram achieved good C-indices of 0.894 (95% confidence interval (CI) [0.866–0.921]) and 0.868 (95% CI [0.811–0.925]) in the training and validation cohorts, respectively, with well-fitted calibration curves.

Conclusion

The nomogram offers good predictive performance for PPCs after thoracoscopic surgery. This model may help distinguish the risk of PPCs and make reasonable treatment choices.

Effect of Intraoperative Ventilation Strategies on Postoperative Pulmonary Complications: A Meta-Analysis

Introduction: The role of intraoperative ventilation strategies in subjects undergoing surgery is still contested. This meta-analysis study was performed to assess the relationship between the low tidal volumes strategy and conventional mechanical ventilation in subjects undergoing surgery. Methods: A systematic literature search up to December 2020 was performed in OVID, Embase, Cochrane Library, PubMed, and Google scholar, and 28 studies including 11,846 subjects undergoing surgery at baseline and reporting a total of 2,638 receiving the low tidal volumes strategy and 3,632 receiving conventional mechanical ventilation, were found recording relationships between low tidal volumes strategy and conventional mechanical ventilation in subjects undergoing surgery. Odds ratio (OR) or mean difference (MD) with 95% confidence intervals (CIs) were calculated between the low tidal volumes strategy vs. conventional mechanical ventilation using dichotomous and continuous methods with a random or fixed-effect model. Results: The low tidal volumes strategy during surgery was significantly related to a lower rate of postoperative pulmonary complications (OR, 0.60; 95% CI, 0.44-0.83, p < 0.001), aspiration pneumonitis (OR, 0.63; 95% CI, 0.46-0.86, p < 0.001), and pleural effusion (OR, 0.72; 95% CI, 0.56-0.92, p < 0.001) compared to conventional mechanical ventilation. However, the low tidal volumes strategy during surgery was not significantly correlated with length of hospital stay (MD, -0.48; 95% CI, -0.99-0.02, p = 0.06), short-term mortality (OR, 0.88; 95% CI, 0.70-1.10, p = 0.25), atelectasis (OR, 0.76; 95% CI, 0.57-1.01, p = 0.06), acute respiratory distress (OR, 1.06; 95% CI, 0.67-1.66, p = 0.81), pneumothorax (OR, 1.37; 95% CI, 0.88-2.15, p = 0.17), pulmonary edema (OR, 0.70; 95% CI, 0.38-1.26, p = 0.23), and pulmonary embolism (OR, 0.65; 95% CI, 0.26-1.60, p = 0.35) compared to conventional mechanical ventilation. Conclusions: The low tidal volumes strategy during surgery may have an independent relationship with lower postoperative pulmonary complications, aspiration pneumonitis, and pleural effusion compared to conventional mechanical ventilation. This relationship encouraged us to recommend the low tidal volumes strategy during surgery to avoid any possible complications.

Effects of high versus low inspiratory oxygen fraction on postoperative clinical outcomes in patients undergoing surgery under general anesthesia: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

To determine whether high perioperative inspired oxygen fraction (FiO₂) compared with low FiO₂ has more deleterious postoperative clinical outcomes in patients undergoing non-thoracic surgery under general anesthesia.

DESIGN

Meta-analysis of randomized controlled trials.

SETTING

Operating room, postoperative recovery room and surgical ward.

PATIENTS

Surgical patients under general anesthesia.

INTERVENTION

High perioperative FiO₂ (≥0.8) vs. low FiO₂ (≤0.5).

MEASUREMENTS

The primary outcome was mortality within 30 days. Secondary outcomes were pulmonary outcomes (atelectasis, pneumonia, respiratory failure, postoperative pulmonary complications [PPCs], and postoperative oxygen parameters), intensive care unit (ICU) admissions, and length of hospital stay. A subgroup analysis was performed to explore the treatment effect by body mass index (BMI).

MAIN RESULTS

Twenty-six trials with a total 4991 patients were studied. The mortality in the high FiO₂ group did not differ from that in the low FiO₂ group (risk ratio [RR] 0.91, 95% confidence interval [CI] 0.42-1.97, P = 0.810). Nor were there any significant differences between the groups in such outcomes as pneumonia (RR 1.19, 95% CI 0.74-1.92, P = 0.470), respiratory failure (RR 1.29, 95% CI 0.82-2.04, P = 0.270), PPCs (RR 1.05, 95% CI 0.69-1.59, P = 0.830), ICU admission (RR 0.94, 95% CI 0.55-1.60, P = 0.810), and length of hospital stay (mean difference [MD] 0.27 d, 95% CI -0.28-0.81, P = 0.340). The high FiO₂ was associated with postoperative atelectasis more often (risk ratio 1.27, 95% CI 1.00-1.62, P = 0.050), and lower postoperative arterial partial oxygen pressure (MD -5.03 mmHg, 95% CI -7.90- -2.16, P < 0.001)_. In subgroup analysis of BMI >30 kg/m², these parameters were similarly affected between the groups.

CONCLUSIONS

The use of high FiO₂ compared to low FiO₂ did not affect the short-term mortality, although it may increase the incidence of atelectasis in adult, non-thoracic patients undergoing surgical procedures. Nor were there any significant differences in other secondary outcomes.