Epidemiology, practice of ventilation and outcome for patients at increased risk of postoperative pulmonary complications: LAS VEGAS - an observational study in 29 countries

Perioperative Oral decontamination and ImmunoNuTrition (POINT) to prevent postoperative pulmonary complications in elderly patients scheduled for elective non-cardiac surgeries: protocol for a multicentre, randomised controlled trial

INTRODUCTION

Elderly patients are known to be vulnerable to postoperative pulmonary complications (PPCs), especially pneumonia. Apart from elder age, preoperative pulmonary diseases, anaemia, malnutrition, dysphagia and frailty may all be contributing factors to PPCs. Poor oral hygiene is a risk factor for PPC as well, as oropharyngeal microflora might be introduced to the lower respiratory tract following endotracheal intubation for general anaesthesia during surgery. Immune regulation, nutrition supplementation and improvement of oropharyngeal microflora might regulate immune and stress response and can be beneficial to elderly patients exposed to surgical stress. In this study, we will explore the effects of perioperative oral decontamination and immunonutrition supplementation on the incidence of postoperative pneumonia in high-risk elderly surgical patients.

METHODS AND ANALYSIS

This study is a multicentre, two-by-two factorial randomised controlled trial evaluating the efficacy of immunonutrition supplementation and oral chlorhexidine decontamination. A total of 592 patients aged 65 years and older who are scheduled for elective non-cardiac surgeries in seven tertiary hospitals in China will be recruited. Patients will be excluded if they have contraindications to the intervention. Patients will be randomised into four groups in a 1:1:1:1 ratio (oral decontamination vs routine oral care, immunonutrition supplementation vs routine nutrition advice). The primary outcome is the incidence of PPCs within 7 days after surgery. The secondary outcomes are the incidence of postoperative pneumonia, infectious complications, Comprehensive Complication Index, postoperative functional recovery, length of hospital stay and hospital expenses. Intention to treat principles will be applied to all outcomes. Descriptive analysis will be used to compare patients' baseline characteristics. Logistic regression will be used to compare the incidence of PPCs within 7 days after surgery between different groups.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Research Ethics Committee of Peking Union Medical College Hospital (I-23PJ953). All participants will provide written informed consent. Study results will be published in peer-reviewed journals and presented at academic conferences.

TRIAL REGISTRATION NUMBER

NCT05971810.

Association of neuromuscular reversal drug with postoperative pulmonary complications in bronchoscopy: definitional challenges

A recent retrospective study examined a composite of postoperative pulmonary complications after neostigmine or sugammadex for reversal of neuromuscular block in patients undergoing interventional pulmonology and bronchoscopic procedures. This study reviewed the electronic medical records of 8557 patients across hospitals within a single health system, finding an increased risk of a composite of postoperative pulmonary complications in those receiving sugammadex (odds ratio 1.44; 95% confidence interval: 1.02-2.05). We discuss the challenge of interpreting conflicting findings in the contemporary perioperative literature arising from heterogeneous definitions of postoperative pulmonary complications.

Effects of breathing circuit insulation on inspired gas conditioning and water vapour condensation: an in vitro study

PURPOSE

During general anesthesia, physiologic conditioning of inspired gases is bypassed. Mechanical ventilation with dry and cold gas from the central gas supply may lead to dehydration of the mucus membranes, cilia dysfunction, retention of secretions, and atelectasis. The use of metabolic fresh gas flow improves the conditioning of inspiratory gases but increases water vapour condensation within the breathing system. We sought to investigate the effects of breathing circuit insulation on the conditioning of inspired gases and the condensation of water vapour.

METHODS

In this in vitro study, we used a mechanical nonheated, nonhumidified lung model with carbon dioxide (CO2) insufflation. We tested foam, cotton, and polyester insulation (FOI, COI, and PEI) against control (noninsulated regular tubing). We measured temperature, absolute humidity (AH), and water vapour condensation after 120 min. We performed 8 measurements per group (total N = 32) and adjusted P values and confidence intervals (CIs) for multiple testing using Bonferroni-Holm adjustment.

RESULTS

Regarding mean AH, FOI performed better than control. The mean (standard deviation [SD]) differences in AH between control and insulation were -0.63 (0.52) g·m-3 H2O for PEI (adjusted 95% CI, -1.42 to 0.17; P = 0.26), -0.63 (0.74) g·m-3 H2O for COI (adjusted 95% CI, -1.42 to 0.17; P = 0.26), and -1.13 (0.35) g·m-3 H2O for FOI (adjusted 95% CI, -1.92 to -0.33; P < 0.001). The mean temperature was higher in insulated circuits. The mean (SD) difference compared to control was 0.42 (0.28) °C for PEI (adjusted 95% CI, 0.05 to 0.79; P = 0.002), 0.62 (0.26) °C for COI (adjusted 95% CI, 0.25 to 0.99; P < 0.001), and -1.07 (0.14) °C for FOI (adjusted 95% CI, 0.70 to 1.44; P < 0.001). Condensation of water vapour was lower in insulated breathing circuits compared with control.

CONCLUSION

Foam-based insulation was the most effective form of insulation of the breathing circuit to increase temperature and AH of inspired gases and to reduce water vapour condensation. Overall, the results of this in vitro study support the principle of breathing circuit insulation as a method for inspired gas conditioning during the use of metabolic flow anesthesia.

Lung ultrasound on first postoperative day predicts out-of-hospital pulmonary complications following video-assisted thoracic surgery: A prospective cohort study

BACKGROUND

The integration of enhanced recovery after surgery (ERAS) protocols into the peri-operative management of video-assisted thoracic surgery (VATS) has facilitated rapid patient recovery, enabling discharge within 48 h. However, postoperative pulmonary complications (PPCs) postdischarge pose significant concerns for patient welfare. Despite the established utility of lung ultrasound (LUS) in diagnosing the causes of dyspnoea, the effectiveness of quantitative LUS in predicting PPCs after VATS remains uncertain.

OBJECTIVES

To determine whether quantitative LUS performed 24 h after surgery can identify patients with a higher risk of developing PPCs within 30 days after discharge from hospital.

DESIGN

Single-centre prospective cohort study.

SETTING

Academic tertiary care medical centre.

PATIENTS

Adults scheduled for elective VATS under general anaesthesia from November 2022 to January 2023.

MAIN OUTCOME MEASURES

This primary aim was to verify the association between lung ultrasound score (LUSS) on postoperative day 1 (POD1) and PPCs. The secondary aim was to identify other relevant peri-operative factors closely related to PPCs and establish a model capable of predicting the risk of PPCs in patients undergoing fast-track VATS.

RESULTS

Of the 200 recruited patients, 182 completed the LUS examination and 30-day follow-up. Of these, 66 (36.2%) developed various types of PPCs. These patients had a higher LUSS on POD 1 ( P  < 0.001), and more subpleural consolidation areas compared to those without PPCs ( P  < 0.001). Receiver-operating characteristics (ROC) analysis identified the optimal LUSS cut-off value at 6 points for predicting the occurrence of PPCs, with an area under the curve (AUC) of 0.838 (95% CI, 0.768 to 0.909). Patients with PPCs had higher rates of immune system diseases and ARISCAT score, longer hospital stay and procalcitonin levels, increased frequency of lobar resection, longer durations of surgical and mechanical ventilation, and greater incidence of unplanned hospital readmissions within 30 days postdischarge, compared with those without PPCs (all P  < 0.001). Multivariable logistic regression analysis indicated that the comorbidity of immune system disease, along with postoperative 24 h LUSS, were independent risk factor for PPCs within 30 days after VATS.

CONCLUSION

LUSS on POD 1 emerged as an independent risk factor for PPCs in fast-track VATS patients and reliably predicted the occurrence of PPCs within 30 days of hospital discharge.

TRIAL REGISTRATION

ClinicalTrials. gov No. ChiCTR2200065865.

Postoperative pulmonary complications in patients undergoing upper abdominal surgery: risk factors and predictive models

Postoperative pulmonary complications (PPCs) are unexpected disorders that occur up to 30 days after surgery, affecting the patient's clinical status and requiring therapeutic intervention. Therefore, it becomes important to assess the patient preoperatively, as many of these complications can be minimized with proper perioperative strategies following a thorough preoperative checkup. Herein, we describe the PPCs and risk factors associated with developing PPCs in patients undergoing upper abdominal surgery. Additionally, we compared the accuracy of the American Society of Anesthesiologists (ASA) score, the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score, the 6-Minute Walk Test (6MWT), and spirometry in predicting PPCs. Consenting patients (>18 years) undergoing elective upper abdominal surgery were recruited from November 2021 to April 2023. Clinical history was noted. Spirometry and 6MWT were both performed. Preoperative ASA and ARISCAT scores were recorded. Postoperative follow-up was conducted to assess respiratory symptoms and the occurrence of PPC. PPC was defined as per EPCO guidelines. A total of 133 patients were recruited, predominantly male. A total of 27 (20.3%) patients developed PPCs. A total of 14 (10.5%) patients had more than one PPC. The most common PPCs developed were pleural effusion (11.3%), respiratory failure (7.5%), and pneumonia (4.5%). We obtained ten statistically significant associated variables on univariable analysis, viz obstructive airway disease (p=0.002), airflow limitation (p=0.043), chest radiography (p<0.001), albumin (p=0.30), blood urea nitrogen (BUN) (p=0.029), aspartate aminotransferase (p=0.019), alanine aminotransferase (p=0.009), forced expiratory volume in one second/forced vital capacity ratio (p=0.006), duration of surgery (p<0.001), and ASA score (p=0.012). On multivariable regression analysis, abnormal chest radiograph [odds ratio: 8.26; (95% confidence interval: 2.58-25.43), p<0.001], BUN [1.05; (1.00-1.09), p=0.033], and duration of surgery [1.44; (1.18-1.76), p<0.001] were found to be independently associated with PPC. The ASA score was found to have better predictive power for the development of PPCs compared to the ARISCAT score, but it is of poor clinical significance. Additionally, 6MWD and spirometry results were found to lack any meaningful predictive power for PPC. To conclude, preoperative evaluation of the chest radiograph, BUN, and duration of surgery are independently associated with developing PPCs. The ASA score performs better than the ARISCAT score in identifying patients at a higher risk of developing PPCs and implementing preventive measures.

Lung recruitment state during induction of general anaesthesia in a prospective observational clinical study in patients without and with obesity

We investigated lung aeration during preoxygenation, mask ventilation, ventilation via endotracheal tube, and the two apnoeic phases in-between. Using electrical impedance tomography we assessed global inhomogeneity, ventral-to-dorsal ventilation distribution, the area of ventilated lung and end-expiratory lung volume loss. Global inhomogeneity was increased after the apnoeic phases (non-obese: 25%, obese: 66%, p<0.005 for both) and re-improved with the first breaths of mechanical ventilation (non-obese) or during mask ventilation only (obese). Ventral ventilation increased after the first (non-obese: 52%, obese: 36%) and second apnoeic phase (non-obese: 46%, obese: 36%) compared to spontaneous breathing (all p<0.005). Ventral ventilation was highest in the first eight breaths following the second apnoeic phase in non-obese patients and in the first breath during mask ventilation in patients with obesity. The area of ventilated lung was smallest during the first or first eight breaths following each apnoeic phase in both patient groups. The decrease of end-expiratory lung volume was more pronounced during the first (non-obese: 411 [95%CI 273, 549] ml, obese: 417 [95%CI 325, 509] ml) compared to the second apnoeic phase (non-obese: 239 [95%CI 166, 312] ml, obese: 285 [95%CI 188, 382] ml, p<0.02 for all cases). We conclude that lung derecruitment occurs during the apnoeic phases of anaesthesia induction and resolves partly with subsequent mechanical ventilation.

The Impact of Interscalene Brachial Plexus Block with Different Concentrations of Ropivacaine on Diaphragmatic Paralysis: A Randomized Controlled Study

Background

This study aims to evaluate the degree of diaphragmatic paralysis by assessing diaphragmatic excursion and pulmonary function following an ultrasound-guided interscalene brachial plexus block with two different concentrations of ropivacaine (0.2% and 0.5%).

Methods

Forty patients undergoing shoulder arthroscopic surgery were randomly assigned to receive ultrasound-guided interscalene brachial plexus block with 20 mL of either 0.2% or 0.5% ropivacaine. Diaphragmatic excursion (DE) and diaphragm thickening fraction (TF) were measured using M-mode ultrasound before and 30 minutes after the block. Pulmonary function was assessed using a portable spirometer. Additional outcomes included pain scores and the occurrence of adverse effects.

Results

DE was significantly reduced 30 minutes after block in the 0.5% group compared to the 0.2% group (p<0.01), as well as the TF (p<0.01). Forced vital capacity (FVC) was also significantly reduced in the 0.5% group 30 minutes after block in the preparation room compared to the 0.2% group (p<0.001). Both 0.2% and 0.5% ropivacaine had similar effects in improving postoperative pain. There were no serious block-related complications in either group.

Conclusion

0.2% ropivacaine may impair pulmonary function less than 0.5% ropivacaine. The clinical significance of these differences requires further investigation.

Effects of Neuraxial or General Anesthesia on the Incidence of Postoperative Pulmonary Complications in Patients Undergoing Peripheral Vascular Surgery: A Randomized Controlled Trial

OBJECTIVES

Postoperative complications after major surgery, especially in vascular procedures, are associated with a significant increase in costs and mortality. Postoperative pulmonary complications (PPCs) have a notable impact on morbidity and mortality. The primary aim of this present study was to evaluate the effects of spinal anesthesia compared with general anesthesia on the incidence of PPCs in patients undergoing lower extremity bypass surgery.

DESIGN

This study was designed as a prospective, randomized controlled clinical trial with 2 parallel arms.

SETTING

Two tertiary teaching hospitals.

PARTICIPANTS

We enrolled 128 adult patients with American Society of Anesthesiologists status II to IV who were scheduled to undergo elective lower extremity arterial bypass surgery.

INTERVENTIONS

Patients were assigned randomly to receive either general anesthesia or spinal anesthesia.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of PPCs and secondary end points included hemodynamic and blood gas analysis perioperatively. A total of 128 patients were included in the study, with 123 patients completing the study protocol. Approximately 26.7% of patients who received general anesthesia experienced PPC, compared with 12.7% of those who received spinal anesthesia (p = 0.051). Patients who underwent spinal anesthesia had a lower incidence of hypotension and required fewer intraoperative vasoactive drugs (p < 0.001).

CONCLUSIONS

In this study, spinal anesthesia did not significantly reduce the incidence of PPCs in patients undergoing peripheral vascular surgery compared with general anesthesia. Neuraxial anesthesia may reduce the incidence of hypotension and the need for hemodynamic pharmacological support in patients undergoing peripheral arterial surgery, although further dedicated studies are required to validate these findings.

Bidirectional cohort study protocol to construct and validate a prediction model for perioperative pulmonary complications in elderly hip fracture patients

Elderly adults with hip fractures are particularly vulnerable to perioperative pulmonary complications (POPCs) throughout the surgical process. While most studies have focused on predicting postoperative pulmonary complications (PPCs), there has been a lack of focus on preoperative and intraoperative phases. To address this gap, this bidirectional cohort study aims to develop and validate a predictive model for POPCs across all surgical stages in elderly patients with hip fracture. This study will involve 3481 patients, with 1914 in the retrospective dataset and 1567 in the prospective dataset, and will analyse 44 perioperative risk factors. LASSO and multiple logistic regression will be used to identify key predictors, and nomogram prediction models will be constructed via the RMS packages. The accuracy and variability of the model will be assessed using receiver operating characteristic (ROC) curve analysis and calibration plots. The primary outcome measure is the incidence of pulmonary complications from hospital admission to 30 days post-surgery, and the secondary outcomes include complications such as heart failure, myocardial infarction, renal failure, deep venous thrombosis, stroke, and death within 30 days post-surgery. This study aims to construct a comprehensive model for predicting POPCs in this patient population and verify its accuracy and ability to differentiate POPCs using both internal and external data.

Associations of intraoperative end-tidal CO2 levels with postoperative outcome-secondary analysis of a worldwide observational study

BACKGROUND

Patients receiving intraoperative ventilation during general anesthesia often have low end-tidal CO2 (etCO2). We examined the association of intraoperative etCO2 levels with the occurrence of postoperative pulmonary complications (PPCs) in a conveniently-sized international, prospective study named 'Local ASsessment of Ventilatory management during General Anesthesia for Surgery' (LAS VEGAS).

METHODS

Patients at high risk of PPCs were categorized as 'low etCO2' or 'normal to high etCO2' patients, using a cut-off of 35 mmHg. The primary endpoint was a composite of previously defined PPCs; the individual PPCs served as secondary endpoints. The need for unplanned oxygen was defined as mild PPCs and severe PPCs included pneumonia, respiratory failure, acute respiratory distress syndrome, barotrauma, and new invasive ventilation. We performed propensity score matching and LOESS regression to evaluate the relationship between the lowest etCO2 and PPCs.

RESULTS

The analysis included 1843 (74 %) 'low etCO2' patients and 648 (26 %) 'normal to high etCO2' patients. There was no difference in the occurrence of PPCs between 'low etCO2' and 'normal to high etCO2' patients (20 % vs. 19 %; RR 1.00 [95 %-confidence interval 0.94 to 1.06]; P = 0.84). The proportion of severe PPCs among total occurring PPCs, were higher in 'low etCO2' patients compared to 'normal to high etCO2' patients (35 % vs. 18 %; RR 1.16 [1.08 to 1.25]; P < 0.001). Propensity score matching did not change these findings. LOESS plot showed an inverse relationship of intraoperative etCO2 levels with the occurrence of PPCs.

CONCLUSIONS

In this cohort of patients at high risk of PPCs, the overall occurrence of PPCs was not different between 'low etCO2' patients and 'normal to high etCO2' patients, but severe PPCs occurred more often in 'low etCO2', with an inverse dose-dependent relationship between intraoperative etCO2 levels and PPCs.

FUNDING

This analysis was performed without additional funding. LAS VEGAS was partially funded and endorsed by the European Society of Anesthesiology and Intensive Care (ESAIC) and the Amsterdam University Medical Centers, location 'AMC'.

REGISTRATION

LAS VEGAS was registered at Clinicaltrials.gov (NCT01601223), first posted on May 17, 2012.

The association between controlling nutritional status and postoperative pulmonary complications in patients with colorectal cancer

Background

Postoperative pulmonary complications (PPCs) significantly impact surgical outcomes, and Controlling Nutritional Status (CONUT) score, a simple and easily available nutritional score, has been demonstrated to be significantly associated with postoperative patient outcomes and complications, including PPCs. However, there are few studies that specifically focus on patients undergoing radical surgery for colorectal cancer (CRC).

Methods

We retrospectively analyzed the clinical data of 2,553 patients who underwent radical surgery for CRC at the Sixth Affiliated Hospital of Sun Yat-sen University. Patients were divided into three groups: normal nutrition group (CONUT≤1), mild malnutrition group (2 ≤ CONUT≤4), and moderate-to-severe malnutrition group (CONUT≥5). Risk factors for PPCs and all-cause mortality were evaluated by multivariate regression. In addition, we assessed surgical outcomes including ICU admission, hospital stay, 1-year mortality and tumor-related mortality.

Results

The incidence of PPCs was 9.0% (n = 230). Multiple regression showed that the higher the CONUT score, the higher the risk of PPCs (mild malnutrition group vs. normal nutrition group, OR: 1.61, 95% CI: 1.18-2.20, p = 0.003; moderate-to-severe malnutrition group vs. normal nutrition group, OR: 2.41, 95% CI: 1.51-3.84, p < 0.001). All-cause mortality was significantly higher in moderate-to-severe malnutrition group than that in normal nutrition group, HR: 1.88, (95% CI: 1.34-2.62, p < 0.001). Older age, male sex, chronic heart disease, open surgery, blood transfusion during surgery, distant metastasis of tumor and colon tumor were all risk factors for PPCs. Furthermore, the malnutrition groups had poor surgical outcomes including postoperative pneumonia (mild vs. normal nutrition, OR: 1.64, 95% CI: 1.07-2.52, p = 0.024; moderate-to-severe vs. normal nutrition, OR: 2.51, 95% CI: 1.36-4.62, p = 0.00), ICU admission (mild vs. normal nutrition, OR: 2.16, 95% CI: 1.31-3.56, p = 0.002; moderate-to-severe vs. normal nutrition, OR: 3.86, 95% CI: 2.07-7.20, p < 0.001), hospital stay ≥14 days (mild vs. normal nutrition, OR: 1.30, 95% CI: 1.08-1.56, p = 0.006) and 1-year mortality (mild vs. normal nutrition, HR: 1.65, 95% CI: 1.11-2.46, p = 0.014; moderate-to-severe vs. normal nutrition, HR: 2.27, 95% CI: 1.28-4.02, p = 0.005).

Conclusion

The preoperative CONUT score is a potential indicator for predicting PPCs and surgical outcomes in CRC patients.

High Positive End-expiratory Pressure (PEEP) with Recruitment Maneuvers versus Low PEEP during General Anesthesia for Surgery: A Bayesian Individual Patient Data Meta-analysis of Three Randomized Clinical Trials

BACKGROUND

The influence of high positive end-expiratory pressure (PEEP) with recruitment maneuvers on the occurrence of postoperative pulmonary complications after surgery is still not definitively established. Bayesian analysis can help to gain further insights from the available data and provide a probabilistic framework that is easier to interpret. The objective was to estimate the posterior probability that the use of high PEEP with recruitment maneuvers is associated with reduced postoperative pulmonary complications in patients with intermediate-to-high risk under neutral, pessimistic, and optimistic expectations regarding the treatment effect.

METHODS

Multilevel Bayesian logistic regression analysis was performed on individual patient data from three randomized clinical trials carried out on surgical patients at intermediate to high risk for postoperative pulmonary complications. The main outcome was the occurrence of postoperative pulmonary complications in the early postoperative period. This study examined the effect of high PEEP with recruitment maneuvers versus low PEEP ventilation. Priors were chosen to reflect neutral, pessimistic, and optimistic expectations of the treatment effect.

RESULTS

Using a neutral, pessimistic, or optimistic prior, the posterior mean odds ratio for high PEEP with recruitment maneuvers compared to low PEEP was 0.85 (95% credible interval, 0.71 to 1.02), 0.87 (0.72 to 1.04), and 0.86 (0.71 to 1.02), respectively. Regardless of prior beliefs, the posterior probability of experiencing a beneficial effect exceeded 90%. Subgroup analysis indicated a more pronounced effect in patients who underwent laparoscopy (odds ratio, 0.67 [0.50 to 0.87]) and those at high risk for postoperative pulmonary complications (odds ratio, 0.80 [0.53 to 1.13]). Sensitivity analysis, considering severe postoperative pulmonary complications only or applying a different heterogeneity prior, yielded consistent results.

CONCLUSIONS

High PEEP with recruitment maneuvers demonstrated a moderate reduction in the probability of postoperative pulmonary complication occurrence, with a high posterior probability of benefit observed consistently across various prior beliefs, particularly among patients who underwent laparoscopy.

Electrical impedance tomography-guided positive end-expiratory pressure titration for perioperative oxygenation and postoperative pulmonary complications: A systematic review and meta-analysis

BACKGROUND

The electrical impedance tomography (EIT)-guided individual positive end-expiratory pressure (PEEP) approach is a noninvasive, radiation-free, and straightforward strategy. However, its validity to prevent postoperative complications remains unclear. To determine whether the EIT-guided PEEP titration in surgery has a higher oxygenation index and lower postoperative complications incidence in patients, we performed a meta-analysis to assess the efficacy. The study design is a systematic review and meta-analysis.

METHODS

Four databases (Cochrane, PubMed, Web of Science, and Embase) were searched from 2000 to November 2022 for this study. Randomized controlled trials of patients selected for general anesthesia were included. The main indicators of the study were oxygenation and postoperative pulmonary complications. Study quality was assessed using the Cochrane Risk and Bias Tool.

RESULTS

A total of 7 articles with 425 subjects were included and were eligible for analysis. Meta-analysis showed that patients had a higher oxygenation index (PaO2/FiO2) after EIT-guided individual PEEP titration compared with other modalities of PEEP titration (6 trials, 351 subjects, standardized mean check = 1.06, 95% confidence interval = 0.59-1.53). For subgroup analysis, the results were still statistically significant both in adult/elder groups and normal/obese groups. No significant advantage was found for the incidence of postoperative pulmonary complications between individual PEEP titration under EIT and other titration strategies (5 trials, 341 subjects, standardized mean check = 0.77, 95% confidence interval = 0.34-1.71). The same results were found in the subgroup analysis.

CONCLUSION

EIT-guided individual PEEP setting significantly improved perioperative oxygenation index compared with other modalities of PEEP ventilation strategies for patients, but no significant differences were found in the incidence of the postoperative pulmonary complications.

Sex dependence of postoperative pulmonary complications - A post hoc unmatched and matched analysis of LAS VEGAS

STUDY OBJECTIVE

Male sex has inconsistently been associated with the development of postoperative pulmonary complications (PPCs). These studies were different in size, design, population and preoperative risk. We reanalysed the database of 'Local ASsessment of Ventilatory management during General Anaesthesia for Surgery study' (LAS VEGAS) to evaluate differences between females and males with respect to PPCs.

DESIGN, SETTING AND PATIENTS

Post hoc unmatched and matched analysis of LAS VEGAS, an international observational study in patients undergoing intraoperative ventilation under general anaesthesia for surgery in 146 hospitals across 29 countries. The primary endpoint was a composite of PPCs in the first 5 postoperative days. Individual PPCs, hospital length of stay and mortality were secondary endpoints. Propensity score matching was used to create a similar cohort regarding type of surgery and epidemiological factors with a known association with development of PPCs.

MAIN RESULTS

The unmatched cohort consisted of 9697 patients; 5342 (55.1%) females and 4355 (44.9%) males. The matched cohort consisted of 6154 patients; 3077 (50.0%) females and 3077 (50.0%) males. The incidence in PPCs was neither significant between females and males in the unmatched cohort (10.0 vs 10.7%; odds ratio (OR) 0.93 [0.81-1.06]; P = 0.255), nor in the matched cohort (10.5 vs 10.0%; OR 1.05 [0.89-1.25]; P = 0.556). New invasive ventilation occurred less often in females in the unmatched cohort. Hospital length of stay and mortality were similar between females and males in both cohorts.

CONCLUSIONS

In this conveniently-sized worldwide cohort of patients receiving intraoperative ventilation under general anaesthesia for surgery, the PPC incidence was not significantly different between sexes.

REGISTRATION

LAS VEGAS was registered at clinicaltrial.gov (study identifier NCT01601223).

The association of vaping and electronic cigarette use with postoperative hypoxemia and respiratory complications: a retrospective cohort analysis

PURPOSE

Initially introduced as a safer alternative to smoking, electronic cigarettes (e-cigarettes) and vaping have since been associated with lung injury. Nevertheless, there is limited perioperative data on their potential contribution to the harmful effects of mechanical ventilation on the lungs. We hypothesized that, in adults undergoing noncardiothoracic surgeries, preoperative vaping/e-cigarette use is associated with hypoxemia during the first postoperative hour, and with an increased incidence of intraoperative and postoperative pulmonary complications.

METHODS

We conducted a retrospective cohort study in which we included patients reporting as vapers/e-cigarette users within one year before surgery as the exposure group, and nonvapers as the control group. The primary outcome was the time-weighted average (TWA) SpO2/FIO2 ratio in the postanesthesia care unit during the first postoperative hour. The secondary outcome was a composite of intraoperative and postoperative pulmonary complications until discharge. We used entropy balancing to adjust for confounding, and fit weighted linear regression and logistic regression models to estimate treatment effects.

RESULTS

A total of 110,940 patients met the inclusion criteria, and 1,941 of these were vapers/e-cigarette users. The average treatment effect on the treated for TWA SpO2/FIO2 ratio (N = 109,217) was estimated to be a mean difference of 4 (95% confidence interval [CI], 1 to 8; P = 0.007). This is equivalent to a 4% change in SpO2 at a 30% FIO2 (or at a fixed FIO2). The difference was statistically significant. The average treatment effect on the treated for experiencing intraoperative and postoperative pulmonary complications (N = 110,940) was an odds ratio of 1.04 (95% CI, 0.71 to 1.54; P = 0.84).

CONCLUSION

Vaping/e-cigarette use was neither associated with clinically significant hypoxemia during the first hour in the postanesthesia care unit nor with an increase in pulmonary complications. Nevertheless, our findings cannot definitively exclude the deleterious effects of vaping and e-cigarette use on the lungs, and anesthesiologists should consider potential perioperative complications.

Association between inspired oxygen fraction and development of postoperative pulmonary complications in thoracic surgery: a multicentre retrospective cohort study

BACKGROUND

Limited data exist to guide oxygen administration during one-lung ventilation for thoracic surgery. We hypothesised that high intraoperative inspired oxygen fraction during lung resection surgery requiring one-lung ventilation is independently associated with postoperative pulmonary complications (PPCs).

METHODS

We performed this retrospective multicentre study using two integrated perioperative databases (Multicenter Perioperative Outcomes Group and Society of Thoracic Surgeons General Thoracic Surgery Database) to study adult thoracic surgical procedures using one-lung ventilation. The primary outcome was a composite of PPCs (atelectasis, acute respiratory distress syndrome, pneumonia, respiratory failure, reintubation, and prolonged ventilation >48 h). The exposure of interest was high inspired oxygen fraction (FiO2), defined by area under the curve of a FiO2 threshold > 80%. Univariate analysis and logistic regression modelling assessed the association between intraoperative FiO2 and PPCs.

RESULTS

Across four US medical centres, 141/2733 (5.2%) procedures conducted in 2716 patients (55% female; mean age 66 yr) resulted in PPCs. FiO2 was univariately associated with PPCs (adjusted OR [aOR]: 1.17, 95% confidence interval [CI]: 1.04-1.33, P=0.012). Logistic regression modelling showed that duration of one-lung ventilation (aOR: 1.20, 95% CI: 1.03-1.41, P=0.022), but not the time-weighted average FiO2 (aOR: 1.01, 95% CI: 1.00-1.02, P=0.165), was associated with PPCs.

CONCLUSIONS

Our results do not support limiting the inspired oxygen fraction for the purpose of reducing postoperative pulmonary complications in thoracic surgery involving one-lung ventilation.

The association between intraoperative low driving pressure ventilation and perioperative healthcare-associated costs: A retrospective multicenter cohort study

STUDY OBJECTIVE

A low dynamic driving pressure during mechanical ventilation for general anesthesia has been associated with a lower risk of postoperative respiratory complications (PRC), a key driver of healthcare costs. It is, however, unclear whether maintaining low driving pressure is clinically relevant to measure and contain costs. We hypothesized that a lower dynamic driving pressure is associated with lower costs.

DESIGN

Multicenter retrospective cohort study.

SETTING

Two academic healthcare networks in New York and Massachusetts, USA.

PATIENTS

46,715 adult surgical patients undergoing general anesthesia for non-ambulatory (inpatient and same-day admission) surgery between 2016 and 2021.

INTERVENTIONS

The primary exposure was the median intraoperative dynamic driving pressure.

MEASUREMENTS

The primary outcome was direct perioperative healthcare-associated costs, which were matched with data from the Healthcare Cost and Utilization Project-National Inpatient Sample (HCUP-NIS) to report absolute differences in total costs in United States Dollars (US$). We assessed effect modification by patients' baseline risk of PRC (score for prediction of postoperative respiratory complications [SPORC] ≥ 7) and effect mediation by rates of PRC (including post-extubation saturation < 90%, re-intubation or non-invasive ventilation within 7 days) and other major complications.

MAIN RESULTS

The median intraoperative dynamic driving pressure was 17.2cmH2O (IQR 14.0-21.3cmH2O). In adjusted analyses, every 5cmH2O reduction in dynamic driving pressure was associated with a decrease of -0.7% in direct perioperative healthcare-associated costs (95%CI -1.3 to -0.1%; p = 0.020). When a dynamic driving pressure below 15cmH2O was maintained, -US$340 lower total perioperative healthcare-associated costs were observed (95%CI -US$546 to -US$132; p = 0.001). This association was limited to patients at high baseline risk of PRC (n = 4059; -US$1755;97.5%CI -US$2495 to -US$986; p < 0.001), where lower risks of PRC and other major complications mediated 10.7% and 7.2% of this association (p < 0.001 and p = 0.015, respectively).

CONCLUSIONS

Intraoperative mechanical ventilation targeting low dynamic driving pressures could be a relevant measure to reduce perioperative healthcare-associated costs in high-risk patients.

Machine learning and preoperative risk prediction: the machines are coming

Preoperative risk prediction is an important component of perioperative medicine. Machine learning is a powerful tool that could lead to increasingly complex risk prediction models with improved predictive performance. Careful consideration is required to guide the machine learning approach to ensure appropriate decisions are made with regard to what we are trying to predict, when we are trying to predict it, and what we seek to do with the results.

The GENERATOR–investigators, Dorland G, Vermeulen TD, Hollmann MW, Schultz MJ, Hol L, Nijbroek SGLH, Breel–Tebbutt JS, Neto AS, Mazzinari G, Gasteiger L, Ball L, Pelosi P, Almac E, Navarro MPA, Battaglini D, Besselink MG, Bokkerink PEMM, van den Broek J, Buise MP, Broens S, Davidson Z, Cambronero OD, Dejaco H, Ensink-Tjaberings PY, Florax AA, de Abreu MG, Godfried MB, Harmon MBA, Helmerhorst HJF, Huhn R, Huhle R, Jetten WD, de Jong M, Koopman JSHA, Koster SCE, de Korte-de Boer DJ, Kuiper GJAJM, Trip CNL, Morariu AM, Nass SA, Oei GTML, Pap−Brugmans AC, Paulus F, Potters JW, Rad M, Robba C, Sarton EY, Servaas S, Smit KF, Stamkot A, Thiel B, Struys MMRF, van de Wint TC, Wittenstein J, Zeillemaker-Hoekstra M, van der Zwan T, Hemmes SNT, van Meenen DMP, Staier N, Mörtl M. Driving pressure during general anesthesia for minimally invasive abdominal surgery (GENERATOR)-study protocol of a randomized clinical trial

BACKGROUND

Intraoperative driving pressure (ΔP) has an independent association with the development of postoperative pulmonary complications (PPCs) in patients receiving ventilation during general anesthesia for major surgery. Ventilation with high intraoperative positive end-expiratory pressure (PEEP) with recruitment maneuvers (RMs) that result in a low ΔP has the potential to prevent PPCs. This trial tests the hypothesis that compared to standard low PEEP without RMs, an individualized high PEEP strategy, titrated to the lowest ΔP, with RMs prevents PPCs in patients receiving intraoperative protective ventilation during anesthesia for minimally invasive abdominal surgery.

METHODS

"DrivinG prEssure duriNg gEneRal AnesThesia fOr minimally invasive abdominal suRgery (GENERATOR)" is an international, multicenter, two-group, patient and outcome-assessor blinded randomized clinical trial. In total, 1806 adult patients scheduled for minimally invasive abdominal surgery and with an increased risk of PPCs based on (i) the ARISCAT risk score for PPCs (≥ 26 points) and/or (ii) a combination of age > 40 years and scheduled surgery lasting > 2 h and planned to receive an intra-arterial catheter for blood pressure monitoring during the surgery will be included. Patients are assigned to either an intraoperative ventilation strategy with individualized high PEEP, titrated to the lowest ΔP, with RMs or one with a standard low PEEP of 5 cm H2O without RMs. The primary outcome is a collapsed composite endpoint of PPCs until postoperative day 5.

DISCUSSION

GENERATOR will be the first adequately powered randomized clinical trial to compare the effects of individualized high PEEP with RMs versus standard low PEEP without RMs on the occurrence of PPCs after minimally invasive abdominal surgery. The results of the GENERATOR trial will support anesthesiologists in their decisions regarding PEEP settings during minimally invasive abdominal surgery.

TRIAL REGISTRATION

GENERATOR is registered at ClinicalTrials.gov (study identifier: NCT06101511) on 26 October 2023.

Enhancing Thoracic Surgery with AI: A Review of Current Practices and Emerging Trends

Artificial intelligence (AI) is increasingly becoming integral to medical practice, potentially enhancing outcomes in thoracic surgery. AI-driven models have shown significant accuracy in diagnosing non-small-cell lung cancer (NSCLC), predicting lymph node metastasis, and aiding in the efficient extraction of electronic medical record (EMR) data. Moreover, AI applications in robotic-assisted thoracic surgery (RATS) and perioperative management reveal the potential to improve surgical precision, patient safety, and overall care efficiency. Despite these advancements, challenges such as data privacy, biases, and ethical concerns remain. This manuscript explores AI applications, particularly machine learning (ML) and natural language processing (NLP), in thoracic surgery, emphasizing their role in diagnosis and perioperative management. It also provides a comprehensive overview of the current state, benefits, and limitations of AI in thoracic surgery, highlighting future directions in the field.

Risk factors for PPCs in laparoscopic non-robotic vs. laparoscopic robotic abdominal surgery (LapRas): rationale and protocol for a patient-level analysis of LAS VEGAS and AVATaR

INTRODUCTION

Postoperative pulmonary complications (PPCs) vary amongst different surgical techniques. We aim to compare the incidence of PPCs after laparoscopic non-robotic versus laparoscopic robotic abdominal surgery.

METHODS AND ANALYSIS

LapRas (Risk Factors for PPCs in Laparoscopic Non-robotic vs Laparoscopic robotic abdominal surgery) incorporates harmonized data from 2 observational studies on abdominal surgery patients and PPCs: 'Local ASsessment of VEntilatory management during General Anaesthesia for Surgery' (LAS VEGAS), and 'Assessment of Ventilation during general AnesThesia for Robotic surgery' (AVATaR). The primary endpoint is the occurrence of one or more PPCs in the first five postoperative days. Secondary endpoints include the occurrence of each individual PPC, hospital length of stay and in-hospital mortality. Logistic regression models will be used to identify risk factors for PPCs in laparoscopic non-robotic versus laparoscopic robotic abdominal surgery. We will investigate whether differences in the occurrence of PPCs between the two groups are driven by differences in duration of anesthesia and/or the intensity of mechanical ventilation.

ETHICS AND DISSEMINATION

This analysis will address a clinically relevant research question comparing laparoscopic and robotic assisted surgery. No additional ethical committee approval is required for this metanalysis. Data will be shared with the scientific community by abstracts and original articles submitted to peer-reviewed journals.

REGISTRATION

The registration of this post-hoc analysis is pending; individual studies that were merged into the used database were registered at clinicaltrials.gov: LAS VEGAS with identifier NCT01601223, AVATaR with identifier NCT02989415.

Effects of lung protection ventilation strategies on postoperative pulmonary complications after noncardiac surgery: a network meta-analysis of randomized controlled trials

BACKGROUND

The purpose of this network meta-analysis was to assess the impact of different protective ventilatory strategies on postoperative pulmonary complications (PPCs).

METHODS

Several databases were searched for randomized controlled trials (RCTs) that were published before October 2023 in a network meta-analysis. We assessed the effect of different lung-protective ventilation strategies on the incidence of PPCs using Bayesian network meta-analysis.

RESULTS

We included 58 studies (11610 patients) in this meta-analysis. The network meta-analysis showed that low tidal volumes (LTVs) combined with iPEEP and recruitment manoeuvres (RM) was associated with significantly lower incidence of PPCs [HTVs: OR = 0.38, 95%CrI (0.19, 0.75), LTVs: OR = 0.33, 95%CrI (0.12, 0.82)], postoperative atelectasis[HTVs: OR = 0.2, 95%CrI (0.08, 0.48), LTVs: OR = 0.47, 95%CrI (0.11, 0.93)], and pneumonia[HTVs: OR = 0.22, 95%CrI (0.09, 0.48), LTVs: OR = 0.27, 95%CrI (0.08,0.89)] than was High tidal volumes (HTVs) or LTVs. LTVs combined with medium-to-high PEEP and RM were associated with significantly lower incidence of postoperative atelectasis, and pneumonia.

CONCLUSION

LTVs combined with iPEEP and RM decreased the incidence of PPCs, postoperative atelectasis, and pneumonia in noncardiac surgery patients. Individual PEEP-guided ventilation was the optimal lung protection ventilation strategy. The quality of evidence is moderate.

TRIAL REGISTRATION

PROSPERO identifier CRD42023399485.

Prediction models for postoperative pulmonary complications in intensive care unit patients after noncardiac thoracic surgery

BACKGROUND

Postoperative pulmonary complication (PPC) is a leading cause of mortality and poor outcomes in postoperative patients. No studies have enrolled intensive care unit (ICU) patients after noncardiac thoracic surgery, and effective prediction models for PPC have not been developed. This study aimed to explore the incidence and risk factors and construct prediction models for PPC in these patients.

METHODS

This study retrospectively recruited patients admitted to the ICU after noncardiac thoracic surgery at West China Hospital, Sichuan University, from July 2019 to December 2022. The patients were randomly divided into a development cohort and a validation cohort at a 70% versus 30% ratio. The preoperative, intraoperative and postoperative variables during the ICU stay were compared. Univariate and multivariate logistic regression analyses were applied to identify candidate predictors, establish prediction models, and compare the accuracy of the models with that of reported risk models.

RESULTS

A total of 475 ICU patients were enrolled after noncardiac thoracic surgery (median age, 58; 72% male). At least one PPC occurred in 171 patients (36.0%), and the most common PPC was pneumonia (153/475, 32.21%). PPC significantly increased the duration of mechanical ventilation (p < 0.001), length of ICU stay (p < 0.001), length of hospital stay (LOS) (p < 0.001), and rate of reintubation (p = 0.047) in ICU patients. Seven risk factors were identified, and then the prediction nomograms for PPC were constructed. At ICU admission, the area under the curve (AUC) was 0.766, with a sensitivity of 0.71 and specificity of 0.60; after extubation, the AUC was 0.841, with a sensitivity of 0.75 and specificity of 0.83. The models showed robust discrimination in both the development cohort and the validation cohort, and they were well calibrated and more accurate than reported risk models.

CONCLUSIONS

ICU patients who underwent noncardiac thoracic surgery were at high risk of developing PPCs. Prediction nomograms were constructed and they were more accurate than reported risk models, with excellent sensitivity and specificity. Moreover, these findings could help assess individual PPC risk and enhance postoperative management of patients.

One-lung ventilation with fixed and variable tidal volumes on oxygenation and pulmonary outcomes: A randomized trial

OBJECTIVE

Test the hypothesis that one-lung ventilation with variable tidal volume improves intraoperative oxygenation and reduces postoperative pulmonary complications after lung resection.

BACKGROUND

Constant tidal volume and respiratory rate ventilation can lead to atelectasis. Animal and human ARDS studies indicate that oxygenation improves with variable tidal volumes. Since one-lung ventilation shares characteristics with ARDS, we tested the hypothesis that one-lung ventilation with variable tidal volume improves intraoperative oxygenation and reduces postoperative pulmonary complications after lung resection.

DESIGN

Randomized trial.

SETTING

Operating rooms and a post-anesthesia care unit.

PATIENTS

Adults having elective open or video-assisted thoracoscopic lung resection surgery with general anesthesia were randomly assigned to intraoperative ventilation with fixed (n = 70) or with variable (n = 70) tidal volumes.

INTERVENTIONS

Patients assigned to fixed ventilation had a tidal volume of 6 ml/kgPBW, whereas those assigned to variable ventilation had tidal volumes ranging from 6 ml/kg PBW ± 33% which varied randomly at 5-min intervals.

MEASUREMENTS

The primary outcome was intraoperative oxygenation; secondary outcomes were postoperative pulmonary complications, mortality within 90 days of surgery, heart rate, and SpO2/FiO2 ratio.

RESULTS

Data from 128 patients were analyzed with 65 assigned to fixed-tidal volume ventilation and 63 to variable-tidal volume ventilation. The time-weighted average PaO2 during one-lung ventilation was 176 (86) mmHg in patients ventilated with fixed-tidal volume and 147 (72) mmHg in the patients ventilated with variable-tidal volume, a difference that was statistically significant (p < 0.01) but less than our pre-defined clinically meaningful threshold of 50 mmHg. At least one composite complication occurred in 11 (17%) of patients ventilated with variable-tidal volume and in 17 (26%) of patients assigned to fixed-tidal volume ventilation, with a relative risk of 0.67 (95% CI 0.34-1.31, p = 0.24). Atelectasis in the ventilated lung was less common with variable-tidal volumes (4.7%) than fixed-tidal volumes (20%) in the initial three postoperative days, with a relative risk of 0.24 (95% CI 0.01-0.8, p = 0.02), but there were no significant late postoperative differences. No other secondary outcomes were both statistically significant and clinically meaningful.

CONCLUSION

One-lung ventilation with variable tidal volume does not meaningfully improve intraoperative oxygenation, and does not reduce postoperative pulmonary complications.

Fluid therapy and pulmonary complications in abdominal surgeries: randomized controlled trial

BACKGROUND

There is no consensus on the most effective strategy for Postoperative Pulmonary Complication (PPC) reduction. This study hypothesized that a Goal-Directed Fluid Therapy (GDFT) protocol of infusion of predetermined boluses reduces the occurrence of PPC in patients undergoing elective open abdominal surgeries when compared with Standard of Care (SOC) strategy.

METHODS

Randomized, prospective, controlled study, conducted from May 2012 to December 2014, with ASA I, II or III patients undergoing open abdominal surgeries, lasting at least 120 min, under general anesthesia, randomized into the SOC and the GDFT group. In the SOC, fluid administration was according to the anesthesiologist's discretion. In the GDFT, the intervention protocol, based on bolus infusion according to blood pressure and delta pulse pressure, was applied. Patients were postoperatively evaluated by an anesthesiologist blinded to the group allocation regarding PPC incidence, mortality, and Length of Hospital Stay (LOHS).

RESULTS

Forty-two patients in the SOC group and 43 in the GDFT group. Nineteen patients (45%) in the SOC and 6 in the GDFT (14%) had at least one PPC (p = 0.003). There was no difference in mortality or LOHS between the groups. Among the patients with PPC, four died (25%), compared to two deaths in patients without PPC (3%) (p = 0.001). The LOHS had a median of 14.5 days in the group with PPC and 9 days in the group without PPC (p = 0.001).

CONCLUSION

The GDFT protocol resulted in a lower rate of PPC; however, the LOHS and mortality did not reduce.

Shoulder Hemiarthroplasty Is Associated With Higher 30-Day Complication Rates Compared With Total Shoulder Arthroplasty for Glenohumeral Osteoarthritis: A Propensity Score Matched Analysis

BACKGROUND

Anatomical total shoulder arthroplasty (TSA) and shoulder hemiarthroplasty (HA) have both been shown to have good outcomes in patients with osteoarthritis of the glenohumeral joint. However, evidence comparing perioperative complications between these procedures in this population is heterogeneous.

MATERIALS AND METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried between the years 2012 and 2021 (10 years in total) for records of patients who underwent either TSA or HA for osteoarthritis of the glenohumeral joint. Patients in each group underwent a 1:1 propensity match for demographic variables. Bivariate and multivariate analyses were performed to compare complications and risk factors between these cohorts.

RESULTS

A total of 4376 propensity-matched patients, with 2188 receiving TSA and 2188 receiving HA, were included in the primary analyses. The HA cohort had a higher rate of any adverse event (7.18% vs 4.8%, P=.001), death (0.69% vs 0.1%, P=.004), sepsis (0.46% vs 0.1%, P=.043), postoperative transfusion (4.62% vs 2.2%, P<.001), postoperative intubation (0.5% vs 0.1%, P=.026), and extended length of stay (23.77% vs 13.1%, P<.001). HA was found to increase the odds of developing these complications when baseline demographics were controlled. Older age (odds ratio, 1.040; 95% CI, 1.021-1.059; P<.001) and lower body mass index (odds ratio, 0.949; 95% CI, 0.923-0.975; P<.001) increased the odds of having any adverse event in the HA cohort but not in the TSA cohort.

CONCLUSION

Compared with TSA, HA appears to be associated with significantly higher rates of 30-day postoperative complications when performed for glenohumeral osteoarthritis. [Orthopedics. 2024;47(4):217-224.].

Combining Spirometry and the ARISCAT Respiratory Risk Assessment Can Improve Postoperative Outcomes and Reduce Mortality Risk in Mexico

Introduction

Although a major goal of preoperative evaluation is to identify risk factors and improve postoperative outcomes, current clinical guidelines in Mexico indicate that preoperative spirometry should only be performed on patients with pulmonary disease. The aim of this study was to compare the incidence of postoperative complications (POC), mortality, and risk factors among adults who did or did not undergo preoperative spirometry, based on their Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) risk level.

Material and methods

An observational, retrospective and comparative study design was used to identify 2059 patients from the General Hospital of Mexico who had an ARISCAT assessment during 2013-2017. Patients were classified in two groups: ARISCAT with spirometry (n = 1306) and ARISCAT without spirometry (n = 753). Chi-square, Fisher's exact test and the Student's t-tests were used to compare groups. Logistic regression was used to identify factors associated with an increased risk of POC and mortality.

Results

In the ARISCAT with spirometry group, 11% of patients had POC, compared with 48% of patients in the ARISCAT without spirometry group. High-risk ARISCAT patients who did not receive spirometry had higher mortality (18%), than those who underwent spirometry (0.4%). Logistic regression results indicate that not performing preoperative spirometry increases the probability of POC and mortality.

Conclusions

Our findings suggest that the combined use of preoperative spirometry and ARISCAT is associated with reduced POC and mortality. Future clinical guidelines should recommend the use of preoperative spirometry for patients with a moderate or high ARISCAT level in Mexico.

Rationale and study design for an Individualized PeriopeRative Open lung VEntilatory approach in Emergency Abdominal Laparotomy/scopy: study protocol for a prospective international randomized controlled trial

BACKGROUND

Postoperative pulmonary complications (PPC) are the most frequent postoperative complications, with an estimated prevalence in elective surgery ranging from 20% in observational cohort studies to 40% in randomized clinical trials. However, the prevalence of PPCs in patients undergoing emergency abdominal surgery is not well defined. Lung-protective ventilation aims to minimize ventilator-induced lung injury and reduce PPCs. The open lung approach (OLA), which combines recruitment manoeuvres (RM) and positive end-expiratory pressure (PEEP) titration, aims to minimize areas of atelectasis and the development of PPCs; however, there is no conclusive evidence in the literature that OLA can prevent PPCs. The purpose of this study is to compare an individualized perioperative OLA with conventional standardized lung-protective ventilation in patients undergoing emergency abdominal surgery with clinical signs of intraoperative lung collapse.

METHODS

Randomized international clinical trial to compare an individualized perioperative OLA (RM plus individualized PEEP and individualized postoperative respiratory support) with conventional lung-protective ventilation (standard PEEP of 5 cmH2O and conventional postoperative oxygen therapy) in patients undergoing emergency abdominal surgery with clinical signs of lung collapse. Patients will be randomised to open-label parallel groups. The primary outcome is any severe PPC during the first 7 postoperative days, including: acute respiratory failure, pneumothorax, weaning failure, acute respiratory distress syndrome, and pulmonary infection. The estimated sample size is 732 patients (366 per group). The final sample size will be readjusted during the interim analysis.

DISCUSSION

The Individualized Perioperative Open-lung Ventilatory Strategy in emergency abdominal laparotomy (iPROVE-EAL) is the first multicentre, randomized, controlled trial to investigate whether an individualized perioperative approach prevents PPCs in patients undergoing emergency surgery.

Utilising intraoperative respiratory dynamic features for developing and validating an explainable machine learning model for postoperative pulmonary complications

BACKGROUND

Timely detection of modifiable risk factors for postoperative pulmonary complications (PPCs) could inform ventilation strategies that attenuate lung injury. We sought to develop, validate, and internally test machine learning models that use intraoperative respiratory features to predict PPCs.

METHODS

We analysed perioperative data from a cohort comprising patients aged 65 yr and older at an academic medical centre from 2019 to 2023. Two linear and four nonlinear learning models were developed and compared with the current gold-standard risk assessment tool ARISCAT (Assess Respiratory Risk in Surgical Patients in Catalonia Tool). The Shapley additive explanation of artificial intelligence was utilised to interpret feature importance and interactions.

RESULTS

Perioperative data were obtained from 10 284 patients who underwent 10 484 operations (mean age [range] 71 [65-98] yr; 42% female). An optimised XGBoost model that used preoperative variables and intraoperative respiratory variables had area under the receiver operating characteristic curves (AUROCs) of 0.878 (0.866-0.891) and 0.881 (0.879-0.883) in the validation and prospective cohorts, respectively. These models outperformed ARISCAT (AUROC: 0.496-0.533). The intraoperative dynamic features of respiratory dynamic system compliance, mechanical power, and driving pressure were identified as key modifiable contributors to PPCs. A simplified model based on XGBoost including 20 variables generated an AUROC of 0.864 (0.852-0.875) in an internal testing cohort. This has been developed into a web-based tool for further external validation (https://aorm.wchscu.cn/).

CONCLUSIONS

These findings suggest that real-time identification of surgical patients' risk of postoperative pulmonary complications could help personalise intraoperative ventilatory strategies and reduce postoperative pulmonary complications.

Effect of the alveolar recruitment maneuver during laparoscopic colorectal surgery on postoperative pulmonary complications: A randomized controlled trial

Intraoperative lung-protective ventilation, including low tidal volume and positive end-expiratory pressure, reduces postoperative pulmonary complications. However, the effect and specific alveolar recruitment maneuver method are controversial. We investigated whether the intraoperative intermittent recruitment maneuver further reduced postoperative pulmonary complications while using a lung-protective ventilation strategy. Adult patients undergoing elective laparoscopic colorectal surgery were randomly allocated to the recruitment or control groups. Intraoperative ventilation was adjusted to maintain a tidal volume of 6-8 mL kg-1 and positive end-expiratory pressure of 5 cmH2O in both groups. The alveolar recruitment maneuver was applied at three time points (at the start and end of the pneumoperitoneum, and immediately before extubation) by maintaining a continuous pressure of 30 cmH2O for 30 s in the recruitment group. Clinical and radiological evidence of postoperative pulmonary complications was investigated within 7 days postoperatively. A total of 125 patients were included in the analysis. The overall incidence of postoperative pulmonary complications was not significantly different between the recruitment and control groups (28.1% vs. 31.1%, P = 0.711), while the mean ± standard deviation intraoperative peak inspiratory pressure was significantly lower in the recruitment group (10.7 ± 3.2 vs. 13.5 ± 3.0 cmH2O at the time of CO2 gas-out, P < 0.001; 9.8 ± 2.3 vs. 12.5 ± 3.0 cmH2O at the time of recovery, P < 0.001). The alveolar recruitment maneuver with a pressure of 30 cmH2O for 30 s did not further reduce postoperative pulmonary complications when a low tidal volume and 5 cmH2O positive end-expiratory pressure were applied to patients undergoing laparoscopic colorectal surgery and was not associated with any significant adverse events. However, the alveolar recruitment maneuver significantly reduced intraoperative peak inspiratory pressure. Further study is needed to validate the beneficial effect of the alveolar recruitment maneuver in patients at increased risk of postoperative pulmonary complications. Trial registration: Clinicaltrials.gov (NCT03681236).

Intraoperative lung protection: strategies and their impact on outcomes

PURPOSE OF REVIEW

The present review summarizes the current knowledge and the barriers encountered when implementing tailoring lung-protective ventilation strategies to individual patients based on advanced monitoring systems.

RECENT FINDINGS

Lung-protective ventilation has become a pivotal component of perioperative care, aiming to enhance patient outcomes and reduce the incidence of postoperative pulmonary complications (PPCs). High-quality research has established the benefits of strategies such as low tidal volume ventilation and low driving pressures. Debate is still ongoing on the most suitable levels of positive end-expiratory pressure (PEEP) and the role of recruitment maneuvers. Adapting PEEP according to patient-specific factors offers potential benefits in maintaining ventilation distribution uniformity, especially in challenging scenarios like pneumoperitoneum and steep Trendelenburg positions. Advanced monitoring systems, which continuously assess patient responses and enable the fine-tuning of ventilation parameters, offer real-time data analytics to predict and prevent impending lung complications. However, their impact on postoperative outcomes, particularly PPCs, is an ongoing area of research.

SUMMARY

Refining protective lung ventilation is crucial to provide patients with the best possible care during surgery, reduce the incidence of PPCs, and improve their overall surgical journey.

Intraoperative Mechanical Power and Postoperative Pulmonary Complications in Noncardiothoracic Elective Surgery Patients: A 10-Year Retrospective Cohort Study

BACKGROUND

Postoperative pulmonary complications is a major issue that affects outcomes of surgical patients. The hypothesis was that the intraoperative ventilation parameters are associated with occurrence of postoperative pulmonary complications.

METHODS

A single-center retrospective cohort study was conducted at the Lille University Hospital, France. The study included 33,701 adults undergoing noncardiac, nonthoracic elective surgery requiring general anesthesia with tracheal intubation between January 2010 and December 2019. Intraoperative ventilation parameters were compared between patients with and without one or more postoperative pulmonary complications (respiratory infection, respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm, and aspiration pneumonitis) within 7 days of surgery.

RESULTS

Among 33,701 patients, 2,033 (6.0%) had one or more postoperative pulmonary complications. The lower tidal volume to predicted body weight ratio (odds ratio per -1 ml·kgPBW-1, 1.08; 95% CI, 1.02 to 1.14; P < 0.001), higher mechanical power (odds ratio per 4 J·min-1, 1.37; 95% CI, 1.26 to 1.49; P < 0.001), dynamic respiratory system compliance less than 30 ml·cm H2O (1.30; 95% CI, 1.15 to 1.46; P < 0.001), oxygen saturation measured by pulse oximetry less than 96% (odds ratio, 2.42; 95% CI, 1.97 to 2.96; P < 0.001), and lower end-tidal carbon dioxide (odds ratio per -3 mmHg, 1.06; 95% CI, 1.00 to 1.13; P = 0.023) were independently associated with postoperative pulmonary complications. Patients with postoperative pulmonary complications were more likely to be admitted to the intensive care unit (odds ratio, 12.5; 95% CI, 6.6 to 10.1; P < 0.001), had longer hospital length of stay (subhazard ratio, 0.43; 95% CI, 0.40 to 0.45), and higher in-hospital (subhazard ratio, 6.0; 95% CI, 4.1 to 9.0; P < 0.001) and 1-yr mortality (subhazard ratio, 2.65; 95% CI, 2.33 to 3.02; P < 0.001).

CONCLUSIONS

In the study's population, decreased rather than increased tidal volume, decreased compliance, increased mechanical power, and decreased end-tidal carbon dioxide were independently associated with postoperative pulmonary complications.

EDITOR’S PERSPECTIVE

Intraoperative mechanical power and postoperative pulmonary complications in low-risk surgical patients: a prospective observational cohort study

BACKGROUND

Inadequate intraoperative mechanical ventilation (MV) can lead to ventilator-induced lung injury and increased risk for postoperative pulmonary complications (PPCs). Mechanical power (MP) was shown to be a valuable indicator for MV outcomes in critical care patients. The aim of this study is to assess the association between intraoperative MP in low-risk surgical patients undergoing general anesthesia and PPCs.

METHODS

Two-hundred eighteen low-risk surgical patients undergoing general anesthesia for elective surgery were included in the study. Intraoperative mechanical ventilatory support parameters were collected for all patients. Postoperatively, patients were followed throughout their hospital stay and up to seven days post discharge for the occurrence of any PPCs.

RESULTS

Out of 218 patients, 35% exhibited PPCs. The average body mass index, tidal volume per ideal body weight, peak inspiratory pressure, and MP were significantly higher in the patients with PPCs than in the patients without PPCs (30.3 ± 8.1 kg/m2 vs. 26.8 ± 4.9 kg.m2, p < 0.001; 9.1 ± 1.9 ml/kg vs. 8.6 ± 1.4 ml/kg, p = 0.02; 20 ± 4.9 cmH2O vs. 18 ± 3.7 cmH2O, p = 0.001; 12.9 ± 4.5 J/min vs. 11.1 ± 3.7 J/min, p = 0.002). A multivariable regression analysis revealed MP as the sole significant predictor for the risk of postoperative pulmonary complications [OR 1.1 (95% CI 1.0-1.2, p = 0.036].

CONCLUSIONS

High intraoperative mechanical power is a risk factor for developing postoperative pulmonary complications. Furthermore, intraoperative mechanical power is superior to other traditional mechanical ventilation variables in identifying surgical patients who are at risk for developing postoperative pulmonary complications.

CLINICAL TRIAL REGISTRATION

NCT03551899; 24/02/2017.

Maintaining moderate versus lower PEEP after cardiac surgery: a propensity-scored matched analysis

BACKGROUND

Setting positive end-expiratory pressure (PEEP) at around 5 cm H2O in the early postoperative period seems a common practice for most patients. It remains unclear if the routine application of higher levels of PEEP confers any meaningful clinical benefit for cardiac surgical patients. The aim of this study was to compare moderate versus conventional lower PEEP on patient-centered outcomes in the intensive care unit (ICU).

METHODS

This is a single-center retrospective study involving patients receiving cardiac surgery from June 2022 to May 2023. Propensity-score matching (PSM) was used to balance the baseline differences. Primary outcomes were the duration of mechanical ventilation and ICU length of stay. Secondary outcomes included PaO2/FiO2 ratio at 24 h and the need for prone positioning during ICU stay.

RESULTS

A total of 334 patients were included in the study, 102 (31%) of them received moderate PEEP (≥ 7 cm H2O) for the major time in the early postoperative period (12 h). After PSM, 79 pairs of patients were matched with balanced baseline data. The results showed that there was marginal difference in the distribution of mechanical ventilation duration (p = 0.05) and the Moderate PEEP group had a higher extubation rate at the day of T-piece trial (65 [82.3%] vs 52 [65.8%], p = 0.029). Applying moderate PEEP was also associated with better oxygenation. No differences were found regarding ICU length of stay and patients requiring prone positioning between groups.

CONCLUSION

In selective cardiac surgical patients, using moderate PEEP compared with conventional lower PEEP in the early postoperative period correlated to better oxygenation, which may have potential for earlier liberation of mechanical ventilation.

Intraoperative individualization of positive-end-expiratory pressure through electrical impedance tomography or esophageal pressure assessment: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

This systematic review of randomized-controlled trials (RCTs) with meta-analyses aimed to compare the effects on intraoperative arterial oxygen tension to inspired oxygen fraction ratio (PaO2/FiO2), exerted by positive end-expiratory pressure (PEEP) individualized trough electrical impedance tomography (EIT) or esophageal pressure (Pes) assessment (intervention) vs. PEEP not tailored on EIT or Pes (control), in patients undergoing abdominal or pelvic surgery with an open or laparoscopic/robotic approach.

METHODS

PUBMED®, EMBASE®, and Cochrane Controlled Clinical trials register were searched for observational studies and RCTs from inception to the end of August 2022. Inclusion criteria were: RCTs comparing PEEP titrated on EIT/Pes assessment vs. PEEP not individualized on EIT/Pes and reporting intraoperative PaO2/FiO2. Two authors independently extracted data from the enrolled investigations. Data are reported as mean difference and 95% confidence interval (CI).

RESULTS

Six RCTs were included for a total of 240 patients undergoing general anesthesia for surgery, of whom 117 subjects in the intervention group and 123 subjects in the control group. The intraoperative mean PaO2/FiO2 was 69.6 (95%CI 32.-106.4 ) mmHg higher in the intervention group as compared with the control group with 81.4% between-study heterogeneity (p < 0.01). However, at meta-regression, the between-study heterogeneity diminished to 44.96% when data were moderated for body mass index (estimate 3.45, 95%CI 0.78-6.11, p = 0.011).

CONCLUSIONS

In patients undergoing abdominal or pelvic surgery with an open or laparoscopic/robotic approach, PEEP personalized by EIT or Pes allowed the achievement of a better intraoperative oxygenation compared to PEEP not individualized through EIT or Pes.

PROSPERO REGISTRATION NUMBER

CRD 42021218306, 30/01/2023.

Postoperative pulmonary complications with high versus standard FiO2 in adult patients undergoing major abdominal surgery: A noninferiority trial

BACKGROUND

Despite the possible clinical benefit of high intraoperative oxygen therapy on surgical site infection, the effect on postoperative respiratory function is debatable. However, it remains yet to be elucidated whether hyperoxia due to a high fraction of inspired oxygen used in conjunction with lung protective ventilation can lead to increased incidence of postoperative pulmonary complications.

METHODS

In this noninferiority randomized trial, an intraoperative high fraction of inspired oxygen of 0.8 (group H) was compared to a standard fraction of inspired oxygen of 0.3 to 0.4 (group S) in adult patients undergoing major elective or emergency surgery. A lung protective ventilation strategy was employed in all patients, including volume control ventilation with a tidal volume of 6 to 8 mL/kg of predicted body weight, respiratory rate of 12 beats per minute, and positive end-expiratory pressure of 5 to 8 cm H2O. Postoperative pulmonary complications were assessed on postoperative days 3 and 5 by the Melbourne group scale.

RESULTS

In this trial, n = 226 patients were randomized; among them, 130 patients underwent routine surgery, and 96 patients underwent emergency surgery. The median (interquartile range) of the patients was 48 (35-58) years, and 47.3% were female. Melbourne group scale scores at postoperative day 3 (median [interquartile range] 2 [1-4] in group S vs 2 [1-3] in group H; the difference in median [95% confidence interval] 0 [0, -1]; P = .13) and day 5 (median [interquartile range] 1 (0-3) in group S vs 1 [0-3] in group H; the difference in median [95% confidence interval] 0 [0, 0.5]; P = .34) were statistically similar in both the groups and the upper margin was within the predefined margin of 1. Incidence of surgical site infection (P = .46), postoperative hospital stay (P = .29), and days alive without antibiotic therapy at postoperative day 28 (P = .95) were similar in both groups.

CONCLUSION

High intraoperative fiO2 was noninferior to standard fiO2 in postoperative pulmonary complications in adult patients undergoing major surgery.

The feasibility of an exercise intervention after robotic-assisted radical cystectomy for urinary bladder cancer, prior to the CanMoRe trial

BACKGROUND

Complications after radical cystectomy for urinary bladder cancer are common. Physical activity after surgery is thought to reduce complications. However, patients with urinary bladder cancer have low levels of physical activity, and interventions supporting physical exercise are needed. This study aimed to evaluate the feasibility of a physical exercise intervention in primary health care. One of the aims of the larger clinical trial will be to reduce complications.

METHODS

Patients with urinary bladder cancer and who were scheduled for a robotic-assisted radical cystectomy were recruited from Karolinska University Hospital, between February and May 2019. The patients had to be mobile, understand Swedish, and live in Stockholm. The exercise programme was conducted at one primary health care setting over 12 weeks. The exercise programme included supervised aerobic and strengthening exercises, which were performed twice a week, as well as daily walks. Feasibility was measured with process feasibility, including eligibility criteria, adherence, and acceptability, and scientific feasibility, including the ability of outcomes to indicate change, safety, and progression in the exercise programme.

RESULTS

Ten patients with a median age of 70 years (min 53-max 86) were included. Adherence to all parts of the intervention was not feasible because of patients' postoperative complications, resulting in dropouts. For the patients who took part in the exercise programme, adherence and acceptability for the exercise period were feasible, but the 6-min walk test was not feasible at discharge from the hospital. Physiotherapists in the primary health care setting perceived the process as feasible. Moreover, the ability of outcomes to indicate change and progression in the exercise programme was feasible, meanwhile no adverse events were registered.

CONCLUSIONS

The exercise intervention was feasible for the patients that took part in the exercise programme, with respect to safety and progression through the exercise programme. Furthermore, this study suggests that some improvements needed to be implemented in the process, prior to the upcoming randomised controlled trial.

Personalized Noninvasive Respiratory Support in the Perioperative Setting: State of the Art and Future Perspectives

Background: Noninvasive respiratory support (NRS), including high-flow nasal oxygen therapy (HFNOT), noninvasive ventilation (NIV) and continuous positive airway pressure (CPAP), are routinely used in the perioperative period. Objectives: This narrative review provides an overview on the perioperative use of NRS. Preoperative, intraoperative, and postoperative respiratory support is discussed, along with potential future areas of research. Results: During induction of anesthesia, in selected patients at high risk of difficult intubation, NIV is associated with improved gas exchange and reduced risk of postoperative respiratory complications. HFNOT demonstrated an improvement in oxygenation. Evidence on the intraoperative use of NRS is limited. Compared with conventional oxygenation, HFNOT is associated with a reduced risk of hypoxemia during procedural sedation, and recent data indicate a possible role for HFNOT for intraoperative apneic oxygenation in specific surgical contexts. After extubation, "preemptive" NIV and HFNOT in unselected cohorts do not affect clinical outcome. Postoperative "curative" NIV in high-risk patients and among those exhibiting signs of respiratory failure can reduce reintubation rate, especially after abdominal surgery. Data on postoperative "curative" HFNOT are limited. Conclusions: There is increasing evidence on the perioperative use of NRS. Use of NRS should be tailored based on the patient's specific characteristics and type of surgery, aimed at a personalized cost-effective approach.

Safety and Feasibility of Intraoperative High PEEP Titrated to the Lowest Driving Pressure (ΔP)-Interim Analysis of DESIGNATION

Uncertainty remains about the best level of intraoperative positive end-expiratory pressure (PEEP). An ongoing RCT ('DESIGNATION') compares an 'individualized high PEEP' strategy ('iPEEP')-titrated to the lowest driving pressure (ΔP) with recruitment maneuvers (RM), with a 'standard low PEEP' strategy ('low PEEP')-using 5 cm H2O without RMs with respect to the incidence of postoperative pulmonary complications. This report is an interim analysis of safety and feasibility. From September 2018 to July 2022, we enrolled 743 patients. Data of 698 patients were available for this analysis. Hypotension occurred more often in 'iPEEP' vs. 'low PEEP' (54.7 vs. 44.1%; RR, 1.24 (95% CI 1.07 to 1.44); p < 0.01). Investigators were compliant with the study protocol 285/344 patients (82.8%) in 'iPEEP', and 345/354 patients (97.5%) in 'low PEEP' (p < 0.01). Most frequent protocol violation was missing the final RM at the end of anesthesia before extubation; PEEP titration was performed in 99.4 vs. 0%; PEEP was set correctly in 89.8 vs. 98.9%. Compared to 'low PEEP', the 'iPEEP' group was ventilated with higher PEEP (10.0 (8.0-12.0) vs. 5.0 (5.0-5.0) cm H2O; p < 0.01). Thus, in patients undergoing general anesthesia for open abdominal surgery, an individualized high PEEP ventilation strategy is associated with hypotension. The protocol is feasible and results in clear contrast in PEEP. DESIGNATION is expected to finish in late 2023.

Postoperative pulmonary complications and mortality after major abdominal surgery. An observational multicenter prospective study

BACKGROUND

Postoperative pulmonary complications (PPCs) significantly contribute to postoperative morbidity and mortality. We conducted a study to determine the incidence of PPCs after major elective abdominal surgery and their association with early and 1-year mortality in patient without pre-existing respiratory disease.

METHODS

We conducted a multicenter observational prospective clinical study in 40 Italian centers. 1542 patients undergoing elective major abdominal surgery were recruited in a time period of 14 days and clinically managed according to local protocol. The primary outcome was to determine the incidence of PPCs. Further, we aimed to identify independent predictors for PPCs and examine the association between PPCs and mortality.

RESULTS

PPCs occurred in 12.6% (95% CI 11.1-14.4%) of patients with significant differences among general (18.3%, 95% CI 15.7-21.0%), gynecological (3.7%, 95% CI 2.1-6.0%) and urological surgery (9.0%, 95% CI 6.0-12.8%). PPCs development was associated with known pre- and intraoperative risk factors. Patients who developed PPCs had longer length of hospital stay, higher risk of 30-days hospital readmission, and increased in-hospital and one-year mortality (OR 3.078, 95% CI 1.825-5.191; P<0.001).

CONCLUSIONS

The incidence of PPCs in patients without pre-existing respiratory disease undergoing elective abdominal surgery is high and associated with worse clinical outcome at one year after surgery. General surgery is associated with higher incidence of PPCs and mortality compared to gynecological and urological surgery.

Impact of Dementia on Incidence and Severity of Postoperative Pulmonary Complications Following Hip Fracture Surgery Among Older Patients

Postoperative pulmonary complications (PPCs) are the leading cause of death following hip fracture surgery. Dementia has been identified as a PPC risk factor that complicates the clinical course. By leveraging electronic health records, this retrospective observational study evaluated the impact of dementia on the incidence and severity of PPCs, hospital length of stay, and postoperative 30-day mortality among 875 older patients (≥65 years) who underwent hip fracture surgery between October 1, 2015 and December 31, 2018 at a health system in the southeastern United States. Inverse probability of treatment weighting using propensity scores was utilized to balance confounders between patients with and without dementia to isolate the impact of dementia on PPCs. Regression analyses revealed that dementia did not have a statistically significant impact on the incidence and severity of PPCs or postoperative 30-day mortality. However, dementia significantly extended the hospital length of stay by an average of 1.37 days.

Effects of individualised positive end-expiratory pressure titration on respiratory and haemodynamic parameters during the Trendelenburg position with pneumoperitoneum: A randomised crossover physiologic trial

BACKGROUND

The Trendelenburg position with pneumoperitoneum during surgery promotes dorsobasal atelectasis formation, which impairs respiratory mechanics and increases lung stress and strain. Positive end-expiratory pressure (PEEP) can reduce pulmonary inhomogeneities and preserve end-expiratory lung volume (EELV), resulting in decreased inspiratory strain and improved gas-exchange. The optimal intraoperative PEEP strategy is unclear.

OBJECTIVES

To compare the effects of individualised PEEP titration strategies on set PEEP levels and resulting transpulmonary pressures, respiratory mechanics, gas-exchange and haemodynamics during Trendelenburg position with pneumoperitoneum.

DESIGN

Prospective, randomised, crossover single-centre physiologic trial.

SETTING

University hospital.

PATIENTS

Thirty-six patients receiving robot-assisted laparoscopic radical prostatectomy.

INTERVENTIONS

Randomised sequence of three different PEEP strategies: standard PEEP level of 5 cmH 2 O (PEEP 5 ), PEEP titration targeting a minimal driving pressure (PEEP ΔP ) and oesophageal pressure-guided PEEP titration (PEEP Poeso ) targeting an end-expiratory transpulmonary pressure ( PTP ) of 0 cmH 2 O.

MAIN OUTCOME MEASURES

The primary endpoint was the PEEP level when set according to PEEP ΔP and PEEP Poeso compared with PEEP of 5 cmH 2 O. Secondary endpoints were respiratory mechanics, lung volumes, gas-exchange and haemodynamic parameters.

RESULTS

PEEP levels differed between PEEP ΔP , PEEP Poeso and PEEP5 (18.0 [16.0 to 18.0] vs. 20.0 [18.0 to 24.0]vs. 5.0 [5.0 to 5.0] cmH 2 O; P  < 0.001 each). End-expiratory PTP and lung volume were lower in PEEP ΔP compared with PEEP Poeso ( P  = 0.014 and P  < 0.001, respectively), but driving pressure, lung stress, as well as respiratory system and dynamic elastic power were minimised using PEEP ΔP ( P  < 0.001 each). PEEP ΔP and PEEP Poeso improved gas-exchange, but PEEP Poeso resulted in lower cardiac output compared with PEEP 5 and PEEP ΔP .

CONCLUSION

PEEP ΔP ameliorated the effects of Trendelenburg position with pneumoperitoneum during surgery on end-expiratory PTP and lung volume, decreased driving pressure and dynamic elastic power, as well as improved gas-exchange while preserving cardiac output.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS00028559, date of registration 2022/04/27). https://drks.de/search/en/trial/DRKS00028559.

Effects of an open lung extubation strategy compared with a conventional extubation strategy on postoperative pulmonary complications after general anesthesia: a single-centre pilot randomized controlled trial

PURPOSE

Postoperative pulmonary complications (PPCs) are a common cause of morbidity. Postoperative atelectasis is thought to be a significant risk factor in their development. Recent imaging studies suggest that patients' extubation may result in similar postoperative atelectasis regardless of the intraoperative mechanical ventilation strategy used. In this pilot trial, we hypothesized that a study investigating the effects of an open lung extubation strategy compared with a conventional one on PPCs would be feasible.

METHODS

We conducted a pilot, single-centre, double-blinded randomized controlled trial. Adult patients at moderate to high risk of PPCs and scheduled for elective surgery were eligible. Patients were randomized to an open lung extubation strategy (semirecumbent position, fraction of inspired oxygen [FIO2] 50%, pressure support ventilation, unchanged positive end-expiratory pressure) or to a conventional extubation strategy (dorsal decubitus position, FIO2 100%, manual bag ventilation). The primary feasibility outcome was global protocol adherence while the primary exploratory efficacy outcome was PPCs.

RESULTS

We randomized 35 patients to the conventional extubation group and 34 to the open lung extubation group. We observed a global protocol adherence of 96% (95% confidence interval, 88 to 99), which was not different between groups. Eight PPCs occurred (two in the conventional extubation group vs six in the open lung extubation group). Less postoperative supplemental oxygen and better lung aeration were observed in the open lung extubation group.

CONCLUSIONS

In this single-centre pilot trial, we observed excellent feasibility. A multicentre pilot trial comparing the effect of an open lung extubation strategy with that of a conventional extubation strategy on the occurrence of PPCs is feasible.

STUDY REGISTRATION DATE

ClinicalTrials.gov (NCT04993001); registered 6 August 2021.

Sugammadex Is Associated With Reduced Pulmonary Complications in Patients With Respiratory Dysfunction

INTRODUCTION

Use of sugammadex is associated with fewer postoperative pulmonary complications (PPCs). This study investigated the relationship between sugammadex and PPCs in specific patients with respiratory dysfunction.

MATERIALS AND METHODS

We reviewed the electronic medical and anesthesia records of patients with respiratory dysfunction who underwent laparoscopic gastric or intestinal surgery at a single center between May 1, 2018 and December 31, 2019. The patients were divided into the sugammadex group and the nonsugammadex group, based on whether they received sugammadex or neostigmine. Binary logistic regression analyses were used to characterize the differences in incidence of PPC.

RESULTS

A total of 112 patients were included, of which 46 patients (41.1%) received sugammadex. In the logistic regression analysis, the incidences of PPC were fewer in the sugammadex group. Postoperative fever (odds ratio [OR] 0.330; 95% confidence interval [CI] 0.137-0.793, P = 0.0213), postoperative intensive care unit admission (OR 0.204; 95% CI 0.065-0.644, P = 0.007), cough (OR 0.143; 95% CI 0.061- 0.333, P < 0.001), pleural effusion (all) (OR: 0.280; 95% CI 0.104- 0.759, P = 0.012), pleural effusion (massive) (OR: 0.142; 95% CI 0.031- 0.653, P = 0.012), and difficulty in breathing (OR: 0.111; 95% CI 0.014-0.849, P = 0.039) showed significant differences between the two groups.

CONCLUSIONS

Sugammadex is associated with a reduction in PPC in patients with respiratory dysfunction.

A 20-year bibliometric analysis of postoperative pulmonary complications: 2003-2022

Background

Postoperative pulmonary complications (PPCs) are known to adversely affect surgical outcomes and patient prognoses, yet no published study provides a qualitative and quantitative analysis of the latest trends and developments in the field of PPCs. Therefore, we conducted a bibliometric analysis of 20 years of publications related to PPCs.

Methods

We examined publications on PPCs published between 2003 and 2022 in the Web of Science Core Collection database to assess trends in the field in four dimensions: trends in publications, major research power, keywords, and co-cited publications.

Results

A total of 1881 articles were analyzed using CiteSpace and VOSviewer. Overall, the number of publications on PPCs has increased in the last two decades, with 42.72% of the publications being produced in the last five years. The United States of America had the highest number of articles, accounting for 21.91% of the total. The institution with the highest number of publications was the University of Genoa, which published 54 articles and showed a general lack of inter-institutional collaboration. The most productive author was Paolo Pelosi, with no core group of authors identified in the field of PPCs. The keyword co-occurrence analysis indicated that the focus of research has shifted over the past 20 years in terms of risk factors, type of surgery, and so on, while "enhanced recovery", "prehabilitation", "driving pressure" and "sugammadex" have received the most recent attention. In the analysis of co-cited literature, the most recent clusters that received attention were driving pressure, lung cancer patient, enhanced recovery, and neuromuscular blockade.

Conclusion

This bibliometric study suggests that pulmonary protective ventilation strategies, neuromuscular blockade reversal, and pulmonary prehabilitation strategy will be the focus of attention in the coming period. More large-scale studies and strengthened institutional collaboration are necessary to generate robust evidence for guiding individualized prevention of PPCs.