Driving Pressure during Thoracic Surgery: A Randomized Clinical Trial

Prospective in-depth analysis of anaesthetic management of spontaneous ventilation VATS for lung cancer resection: a matched pairs comparison to intubated VATS

BACKGROUND

Spontaneous ventilation video-assisted thoracoscopic surgery (SV-VATS) has been propagated for nearly two decades without a prospective in-depth analysis of anaesthetic management and anaesthetic processing times. This would be important as anaesthetic management of SV-VATS imposes fundamental changes to standards in thoracic anaesthesia and may increase anaesthetic risks. Therefore, this study aimed to provide such in-depth analysis and compare the results to data from matched intubated VATS (I-VATS) patients. 3D-reconstruction of bronchial airways helped to estimate the risk reduction by avoiding double-lumen tube (DLT) intubation according to common selection methods in SV-VATS patients.

METHODS

SV-VATS patients receiving anatomical (N = 22) and non-anatomical (N = 16) lung cancer resections were prospectively enrolled. A retrospective I-VATS control cohort (N = 76) allowed for a 2:1 propensity score matching. DLT sizes necessary for SV-VATS patients according to common selection methods were evaluated by 3D-reconstruction of the left main bronchus and the ≥ 1 mm criterion.

RESULTS

SV-VATS patients required substantially less propofol dosage (P < 0.001) with an increase in variability of drug dosing (P < 0.001) and higher BIS values (P < 0.001) as compared to I-VATS patients. SV-VATS lead to higher variability in respiratory parameters (P < 0.001) with less driving pressure (P < 0.001) and similar mean tidal volumes, oxygenation, and hemodynamic parameters compared to I-VATS. Spontaneous ventilation was achieved by allowing for permissive hypercapnia and respiratory acidosis. Anaesthetic processing time was reduced by 7 min (P < 0.001). 5-10% of female and 5% of male patients would have received a DLT larger than their bronchial airway.

CONCLUSIONS

Our study provides the first prospective quantitative in-depth analysis of a standardised anaesthetic management regime for SV-VATS, including anaesthetic processing times. Respiratory parameters during SV-VATS are compatible with reduced mechanical power as compared to patients undergoing I-VATS. The anaesthetic management regime reduced the risk of airway damage imposed by choosing too-large DLTs in up to 10% of patients without compromising oxygenation and hemodynamic stability. Changes in anaesthetic processing time by 7 min would not allow for a higher caseload of SV-VATS for lung cancer surgery.

CLINICAL TRIAL NUMBER

Not applicable.

Effect of driving pressure-guided individualized positive end-expiratory pressure (PEEP) ventilation strategy on postoperative atelectasis in patients undergoing laparoscopic surgery as assessed by ultrasonography: study protocol for a prospective randomized controlled trial

BACKGROUND

Ventilator-induced lung injury caused by mechanical ventilation under general anesthesia as well as CO2 pneumoperitoneum and special positions for laparoscopy may increase the risk of postoperative pulmonary complications (PPCs). Lung protective ventilation under general anesthesia is advised by the guidelines to lower the risk of PPCs in surgical patients. However, there is considerable controversy about the optimal level of positive end-expiratory pressure (PEEP) and how to set it. Driving pressure reflects the overall respiratory stress and high driving pressure is an independent risk factor for PPCs. The purpose of this study is to explore whether driving pressure-guided individualized PEEP ventilation can lower the incidence of postoperative atelectasis by improving respiratory mechanics during laparoscopic surgery consequently lowering the incidence of PPCs compared with the traditional fixed PEEP ventilation strategy.

METHODS

The study will be a single-center, prospective, randomized controlled clinical study. A total of 106 adult patients with medium-to-high-risk PPCs undergoing laparoscopic surgery for more than 2 h will be randomly assigned in a 1:1 ratio to receive an individualized PEEP guided by minimum driving pressure (group D) or a fixed PEEP of 5 cmH2O (group C). Patients in group C will maintain a PEEP of 5 cmH2O throughout the whole process, and patients in group D will be administered individualized PEEP after the start of pneumoperitoneum to achieve minimum driving pressure until the end of the operation. The primary outcome is the LUS score at 24 h postoperatively. The secondary outcomes are the LUS scores at other time points, intraoperative respiratory mechanics and oxygenation index, incidence and specific types of PPCs at 7 days postoperatively.

DISCUSSION

This study will better evaluate the effect of individualized PEEP application guided by driving pressure on the incidence of postoperative atelectasis based on ultrasound assessment consequently the incidence of PPCs in patients undergoing prolonged laparoscopic surgery. The results may provide a clinical evidence for optimizing perioperative lung protection strategies.

TRIAL REGISTRATION

www.chictr.org.cn ChiCTR2300079041. Registered on December 25, 2023.

Development and validation of a nomogram for predicting postoperative pulmonary complications in older patients undergoing noncardiac thoracic surgery: a prospective, bicentric cohort study

BACKGROUND

The ARISCAT score, a prospectively developed generic classification for postoperative pulmonary complications (PPCs), has shown excellent predictive performance in general surgery. However, there is no reliable classification instrument for PPCs prediciton in thoracic surgery.

OBJECTIVE

This study aimed to develop and validate a novel nomogram for estimating the risk of pulmonary complications in older patients (≥ 65 years) within 30 days after NCTS.

METHODS

A nomogram was developed using predefined candidate predictors of 30-day PPCs. It was fitted with least absolute shrinkage and selection operator and logistic regression methods. Internal validation was performed using a bootstrap-resampling approach, while external validation used an independent, temporally separated cohort. The model's performance was assessed based on its discriminative potential (area under the receiver operating characteristic curve [AUC]), predictive ability (calibration plots), and clinical utility (net benefit).

RESULTS

In the development (n = 1449) and validation (n = 449) cohorts, 34.9% and 31.4% of patients, respectively, developed pulmonary complications 30 days post-surgery. The final nomogram incorporated eight predictors (age, surgical approach, desaturation of < 92% for more than 2 min, duration of surgery, smoking status, FEV1/FVC%, respiratory infection in the last 30 days, and neoadjuvant chemotherapy). The nomogram showed excellent discrimination (AUC = 0.866, 95% confidence interval [CI], 0.846-0.885), calibration (Hosmer- Lemeshow test, P = 0.97) and overall performance (Brier score = 0.014) in the development cohort. Similar results were observed in the external validation cohort (AUC = 0.825, 95% CI, 0.786-0.864). A decision curve analysis indicated that the nomogram offers a positive net benefit compared with the ARISCAT and LAS VEGAS scores.

CONCLUSIONS

This novel nomogram can reliably identify older patients with a high risk for pulmonary complications within 30 days after NCTS.

TRIAL REGISTRATION

ChiCTR2100051170.

Mechanical Protective Ventilation: New Paradigms in Thoracic Surgery

One-lung ventilation (OLV) in thoracic anesthesia poses dual challenges: preventing hypoxemia and minimizing ventilator-associated lung injury (VALI). Advances such as fiberoptic bronchoscopy and improved anesthetic techniques have reduced hypoxemia, yet optimal management strategies remain uncertain. Protective ventilation, involving low tidal volumes (4-6 mL/kg), individualized PEEP, and selective alveolar recruitment maneuvers (ARM), seek to balance oxygenation and lung protection. However, questions persist regarding the ideal application of PEEP and ARM, as well as their integration into clinical practice. As for PEEP and ARM, further research is needed to address key questions and establish new guidelines.

Individualized PEEP titration by lung compliance during one-lung ventilation: a meta-analysis

BACKGROUND

Despite the physiological advantages of positive end-expiratory pressure (PEEP), its optimal utilization during one-lung ventilation (OLV) remains uncertain. We aimed to investigate whether individualized PEEP titration by lung compliance is associated with a reduced risk of postoperative pulmonary complications during OLV.

METHODS

We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials until April 1, 2024, to identify published randomized controlled trials that compared individualized PEEP titration by lung compliance with fixed PEEP during OLV. The primary outcome was a composite of postoperative pulmonary complications. Secondary outcomes included clinical outcomes (pneumonia, atelectasis, ARDS, cardiovascular complications, mortality), respiratory mechanics, gas exchanges, and hemodynamic variables. Subgroup analyses were conducted for the primary outcome according to the PEEP titration method (dynamic compliance vs. driving pressure/static compliance, stepwise decremental vs. incremental strategy).

RESULTS

Ten trials involving 3426 patients were included. Compared with fixed PEEP, individualized PEEP titration by lung compliance was associated with reduced risk of a composite of postoperative pulmonary complications (eight trials, 3351 patients, risk ratio [RR] 0.55, 95% CI 0.38-0.78). Subgroup analyses suggested the association was evident in the subgroup with titration by dynamic compliance rather than driving pressure/static compliance and in the subgroup with PEEP titration by stepwise decremental but not stepwise incremental strategy. Individualized PEEP titration by lung compliance was also associated with a reduced risk of pneumonia (RR 0.71, 95% CI 0.52-0.96) and atelectasis (RR 0.63, 95% CI 0.45-0.88), higher dynamic compliance, PaO2, PaO2/FiO2, and lower driving pressure. The individualized and fixed PEEP groups did not differ in ARDS, cardiovascular complications, mortality, peak pressure, plateau pressure, PaCO2, heart rate, and mean arterial pressure.

CONCLUSIONS

Compared with fixed PEEP, individualized PEEP titration by lung compliance is associated with a reduced risk of postoperative pulmonary complications during OLV, especially in PEEP titration by dynamic compliance or stepwise decremental strategy. It improves respiratory mechanics and oxygenation with no difference in hemodynamic variables. Trial registration number ClinicalTrials.gov (PROSPERO No. CRD42024529980).

Clinical practice of one-lung ventilation in mainland China: a nationwide questionnaire survey

BACKGROUND

Limited information is available regarding the application of lung-protective ventilation strategies during one-lung ventilation (OLV) across mainland China. A nationwide questionnaire survey was conducted to investigate this issue in current clinical practice.

METHODS

The survey covered various aspects, including respondent demographics, the establishment and maintenance of OLV, intraoperative monitoring standards, and complications associated with OLV.

RESULTS

Five hundred forty-three valid responses were collected from all provinces in mainland China. Volume control ventilation mode, 4 to 6 mL per kilogram of predictive body weight, pure oxygen inspiration, and a low-level positive end-expiratory pressure ≤ 5 cm H2O were the most popular ventilation parameters. The most common thresholds of intraoperative respiration monitoring were peripheral oxygen saturation (SpO2) of 90-94%, end-tidal CO2 of 45 to 55 mm Hg, and an airway pressure of 30 to 34 cm H2O. Recruitment maneuvers were traditionally performed by 94% of the respondents. Intraoperative hypoxemia and laryngeal injury were experienced by 75% and 51% of the respondents, respectively. The proportions of anesthesiologists who frequently experienced hypoxemia during OLV were 19%, 24%, and 7% for lung, cardiovascular, and esophageal surgeries, respectively. Up to 32% of respondents were reluctant to perform lung-protective ventilation strategies during OLV. Multiple regression analysis revealed that the volume-control ventilation mode and an SpO2 intervention threshold of < 85% were independent risk factors for hypoxemia during OLV in lung and cardiovascular surgeries. In esophageal surgery, working in a tier 2 hospital and using traditional ventilation strategies were independent risk factors for hypoxemia during OLV. Subgroup analysis revealed no significant difference in intraoperative hypoxemia during OLV between respondents who performed lung-protective ventilation strategies and those who did not.

CONCLUSIONS

Lung-protective ventilation strategies during OLV have been widely accepted in mainland China and are strongly recommended for esophageal surgery, particularly in tier 2 hospitals. Implementing volume control ventilation mode and early management of oxygen desaturation might prevent hypoxemia during OLV.

Lung protective ventilation guided by driving pressure improves pulmonary outcomes in heart transplantation

This study aimed to investigate whether driving pressure-guided ventilation can reduce postoperative pulmonary complications in patients who have undergone heart transplantation. Patients who underwent orthotopic heart transplantation were divided into two groups according to the perioperative ventilation strategy: (1) conventional lung-protective ventilation (group C) and (2) driving pressure-guided ventilation (group D). The primary outcome was the occurrence of postoperative pulmonary complications within 30 days of surgery. Univariate and multivariate logistic regression analyses were performed to evaluate the independent risk factors associated with postoperative pulmonary complications (PPCs). Compared with group C, patients in group D exhibited lower driving pressure. Oxygenation improved significantly in the early period after surgery in patients in group D. Group C exhibited a higher number of patients with postoperative pulmonary complications, especially respiratory infections and atelectasis. Patients in group D experienced a shorter duration of postoperative mechanical ventilation and a shorter stay in the intensive care unit. The conventional ventilation strategy, the high driving pressure level and the low PaO2 value at the end of the surgery were the independent risk factors for PPCs in heart transplantation. Compared with conventional lung-protective ventilation, driving pressure-guided ventilation was associated with improved pulmonary oxygenation and lower incidences of pulmonary complications among patients after heart transplantation.

Association of mechanical power and postoperative pulmonary complications among young children undergoing video-assisted thoracic surgery: A retrospective study

BACKGROUND

Previous studies have discussed the correlation between mechanical power (MP) and lung injury. However, evidence regarding the relationship between MP and postoperative pulmonary complications (PPCs) in children remains limited, specifically during one-lung ventilation (OLV).

OBJECTIVES

Propensity score matching was employed to generate low MP and high MP groups to verify the relationship between MP and PPCs. Multivariable logistic regression was performed to identify risk factors of PPCs in young children undergoing video-assisted thoracic surgery (VATS).

DESIGN

A retrospective study.

SETTING

Single-site tertiary children's hospital.

PATIENTS

Children aged ≤2 years who underwent VATS between January 2018 and February 2023.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The incidence of PPCs.

RESULTS

Overall, 581 (median age, 6 months [interquartile range: 5-9.24 months]) children were enrolled. The median [interquartile range] MP during OLV were 2.17 [1.84 to 2.64) J min-1. One hundred and nine (18.76%) children developed PPCs. MP decreased modestly during the study period (2.63 to 1.99 J min-1; P < 0.0001). In the propensity score matched cohort for MP (221 matched pairs), MP (median MP 2.63 vs. 1.84 J min-1) was not associated with a reduction in PPCs (adjusted odds ratio, 1.43; 95% CI, 0.87 to 2.37; P = 0.16). In the propensity score matched cohort for dynamic components of MP (139 matched pairs), dynamic components (mean 2.848 vs. 4.162 J min-1) was not associated with a reduction in PPCs (adjusted odds ratio, 1.62; 95% CI, 0.85 to 3.10; P  = 0.15).The multiple logistic analysis revealed PPCs within 7 days of surgery were associated with male gender, OLV duration >90 min, less surgeon's experience and lower positive end-expiratory pressure (PEEP) value.

CONCLUSIONS

MP and dynamic components were not associated with PPCs in young children undergoing VATS, whereas PPCs were associated with male gender, OLV duration >90 min, less surgeon's experience and lower PEEP value.

TRIAL REGISTRATION

ChiCTR2300074649.

Protective mechanical ventilation in critically ill patients after surgery

PURPOSE OF REVIEW

This review aims to provide an updated overview of lung protective strategies in critically ill patients after surgery, focusing on the utility of postoperative open-lung ventilation during the transition from the operating room to the intensive care unit.

RECENT FINDINGS

Mechanically ventilated patients after surgery represent a challenge in the intensive care unit. Different protective strategies have been proposed to minimize the risk of ventilator-induced lung injury (VILI) and facilitate adequate weaning from mechanical ventilation. Fast-track extubation protocols, increasingly standard in the care of critically ill patients postsurgery, have demonstrated improvements in recovery and reductions in acute lung injury, primarily based on retrospective studies. Open-lung ventilation strategies, such as individualization of positive-end expiratory pressure based on driving pressure and postoperative noninvasive ventilation support with high-flow nasal cannula, are becoming standard of care in high-risk surgical patients after major abdominal or thoracic surgeries.

SUMMARY

Mechanical ventilation in surgical patients should adhere to lung protective strategies (i.e., individualizing positive end expiratory pressure and prioritize alveolar recruitment) during the transition from the operating room to the intensive care unit.

Effect of inspiratory oxygen fraction during driving pressure-guided ventilation strategy on pulmonary complications following open abdominal surgery: A randomized controlled trial

STUDY OBJECTIVE

The aim of the present study was to determine the effect of 30 % fraction of inspired oxygen (FIO2) compared with 80 % FIO2 in the context of driving pressure-guided ventilation strategy on pulmonary complications following open abdominal surgery.

DESIGN

A single-center, prospective, randomized controlled trial.

SETTING

Tertiary university hospital in China.

PATIENTS

514 adult patients, ASA I-III and scheduled for major open abdominal surgery under general anesthesia.

INTERVENTIONS

Patients were randomly assigned to receive either 30 % or 80 % FIO2 during the intraoperative period. All patients received driving pressure-guided ventilation strategy, including low tidal volume and individualized PEEP set at lowest driving pressure.

MEASUREMENTS

The primary outcome was the incidence of a composite of pulmonary complications within the 7 days postoperatively. The severity of pulmonary complications, extrapulmonary complications, and other secondary outcomes were also assessed.

MAIN RESULTS

Of 1553 patients assessed for eligibility, 514 patients were randomly assigned and analyzed with intention-to-treat principle. Patients receiving 30 % FIO2 had a significantly lower incidence of postoperative pulmonary complications (PPCs) compared to those receiving 80 % FIO2 (46.3 %vs. 64.6 %; RR, 0.72; 95 % CI, 0.61-0.84; P < 0.001). The severity score of PPCs was significantly reduced in the 30 % FIO2 group compared with that in the 80 % FIO2 group within the 7 postoperative days (P < 0.001). Dynamic compliance was significantly greater in 30 % FIO2 group at the end of surgery (56 [48-66] vs. 53 [46-62], P = 0.027). More patients in the 80 % FIO2 group developed oxygen desaturation (SpO2 < 94 %) on air intake during PACU stay (18.5 %vs. 30.4 %; RR, 0.61; 95 % CI, 0.44-0.84; P = 0.002; 30 % FIO2 group vs.80 % FIO2 group).

CONCLUSIONS

In patients undergoing open abdominal surgery, using a 30 % FIO2, compared with 80 % FIO2, in context of driving pressure-guided ventilation strategy, intraoperatively reduced the incidence and severity of pulmonary complications within the first 7 postoperative days.

Lung-protective ventilation and postoperative pulmonary complications during pulmonary resection in children: A prospective, single-centre, randomised controlled trial

BACKGROUND

Children are more susceptible to postoperative pulmonary complications (PPCs) due to their smaller functional residual capacity and higher closing volume; however, lung-protective ventilation (LPV) in children requiring one-lung ventilation (OLV) has been relatively underexplored.

OBJECTIVES

To evaluate the effects of LPV and driving pressure-guided ventilation on PPCs in children with OLV.

DESIGN

Randomised, controlled, double-blind study.

SETTING

Single-site tertiary hospital, 6 May 2022 to 31 August 2023.

PATIENTS

213 children aged < 6 years, planned for lung resection secondary to congenital cystic adenomatoid malformation.

INTERVENTIONS

Children were randomly assigned to LPV ( n  = 142) or control ( n  = 71) groups. Children in LPV group were randomly assigned to either driving pressure group ( n  = 70) receiving individualised positive end-expiratory pressure (PEEP) to deliver the lowest driving pressure or to conventional protective ventilation group ( n  = 72) with fixed PEEP of 5 cmH 2 O.

MAIN OUTCOME MEASURES

The primary outcome was the incidence of PPCs within 7 days after surgery. Secondary outcomes were pulmonary mechanics, oxygenation and mechanical power.

RESULTS

The incidence of PPCs did not differ between the LPV (24/142, 16.9%) and the control groups (15/71, 21.1%) ( P  = 0.45). The driving pressure was lower in the driving pressure group than in the 5 cmH 2 O PEEP group (15 vs. 17 cmH 2 O; P   =  0.001). Lung compliance and oxygenation were higher while the dynamic component of mechanical power was lower in the driving pressure group than in the 5 cmH 2 O PEEP group. The incidence of PPCs did not differ between the driving pressure (11/70, 15.7%) and the 5 cmH 2 O PEEP groups (13/72, 18.1%) ( P   =  0.71).

CONCLUSIONS

LPV did not decrease the occurrence of PPCs compared to non-protective ventilation. Although lung compliance and oxygenation were higher in the driving pressure group than in the 5 cmH 2 O PEEP group, these benefits did not translate into significant reductions in PPCs. However, the study is limited by a small sample size, which may affect the interpretation of the results. Future research with larger sample sizes is necessary to confirm these findings.

TRIAL REGISTRATION

ChiCTR2200059270.

Individualized positive end-expiratory pressure in laparoscopic surgery: a randomized controlled trial

BACKGROUND

The reduction in functional residual capacity (FRC) is a significant pathological factor in the development of postoperative pulmonary complications. Appropriate positive end-expiratory pressure (PEEP) is critical to preserve FRC during mechanical ventilation. Our previous study suggests that using driving pressure-guided PEEP can reduce postoperative pulmonary complications. In this study, we hypothesize that individualized PEEP can increase immediate postoperative FRC and improve lung ventilation.

METHODS

This single-centered, randomized controlled trial included a total of 91 patients scheduled for laparoscopic surgery for colorectal carcinoma. Patients were randomly assigned to receive individualized PEEP guided by minimum driving pressure or a fixed PEEP of six cmH2O. The primary outcome was postoperative FRC. Secondary outcomes included the incidence of postoperative pulmonary complications, postoperative Oxygenation Index, alveolar-arterial oxygen tension difference (PA-aO2), intrapulmonary shunt (QS/QT), and Respiratory Index, as well as lung ventilation measured by electrical impedance tomography.

RESULTS

The median value of PEEP in the individualized group was 14 cmH2O, with an interquartile range of 12-14 cmH2O. The postoperative FRC was significantly higher in the individualized PEEP group than that in the PEEP six cmH2O group (32.8 [12.8] vs. 25.0 [12.6] mL/kg, P=0.004). Patients receiving driving pressure-guided PEEP also had significantly higher Oxygenation Index, better ventilation distribution, and lower PA-aO2, QS/QT, and Respiratory Index.

CONCLUSIONS

Driving pressure-guided PEEP can preserve postoperative FRC and provide better ventilation and oxygenation for patients undergoing laparoscopic colorectal surgery.

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.

Impact of an enhanced recovery after surgery program integrating cardiopulmonary rehabilitation on post-operative prognosis of patients treated with CABG: protocol of the ERAS-CaRe randomized controlled trial

BACKGROUND

Coronary artery bypass grafting is associated with a high occurrence of postoperative cardiopulmonary complications. Preliminary evidence suggested that enhanced recovery after surgery can effectively reduce the occurrence of postoperative cardiopulmonary complications. However, enhanced recovery after surgery with systematic integration of cardiopulmonary rehabilitation (ERAS-CaRe) into for Coronary artery bypass grafting has not been evaluated so far. We thus design the ERAS-CaRe randomized-controlled trial to evaluate possible superiority of embedding cardiopulmonary rehabilitation in ERAS over ERAS alone as well as to investigate effects of differential timing of cardiopulmonary rehabilitation within enhanced recovery after surgery (pre-, post-, perio-operative) on post-operative cardiopulmonary complications following Coronary artery bypass grafting surgery.

METHODS

ERAS-CaRe is a pragmatic, randomized-controlled, parallel four-arm, clinical trial. Three hundred sixty patients scheduled for Coronary artery bypass grafting in two Chinese hospitals will be grouped randomly into (i) Standard enhanced recovery after surgery or (ii) pre-operative ERAS-CaRe or (iii) post-operative ERAS-CaRe or (iv) perio-operative ERAS-CaRe. Primary outcome is the occurrence of cardiopulmonary complications at 10 days after Coronary artery bypass grafting. Secondary outcomes include the occurrence of other individual complications including cardiac, pulmonary, stroke, acute kidney injury, gastrointestinal event, ICU delirium rate, reintubation rate, early drainage tube removal rate, unplanned revascularization rate, all-cause mortality, ICU readmission rate, plasma concentration of myocardial infarction-related key biomarkers etc. DISCUSSION: The trial is designed to evaluate the hypothesis that a cardiopulmonary rehabilitation based enhanced recovery after surgery program reduces the occurrence of cardiopulmonary complications following Coronary artery bypass grafting and to determine optimal timing of cardiopulmonary rehabilitation within enhanced recovery after surgery. The project will contribute to increasing the currently limited knowledge base in the field as well as devising clinical recommendations.

TRIAL REGISTRATION

The trial was registered at the Chinese Clinical Trials Registry on 25 August 2023 (ChiCTR2300075125; date recorded: 25/8/2023, https://www.chictr.org.cn/ ).

Risk of pulmonary complications after video-assisted thoracoscopic pulmonary resection in children

BACKGROUND

Postoperative pulmonary complications (PPCs) are associated with high mortality and morbidity rates. Children are more susceptible to PPCs owing to smaller functional residual capacity and greater closing volume. Risk factors of PPCs in children undergoing lung resection remain unclear.

METHODS

This retrospective study enrolled children who underwent video-assisted thoracoscopic surgery between January 2018 and February 2023. The primary outcome was PPC occurrence. Multivariate logistic regression was used to analyze risk factors for PPCs.

RESULTS

Overall, 640 children were analyzed; their median age was 7 (interquartile range: 5-11) months, and the median tidal volume was 7.66 (6.59-8.49) mL/kg. One hundred and seventeen (18.3%) developed PPCs. PPCs were independently associated with male sex (odds ratio [OR], 1.83; 95% confidence interval [CI], 1.17-2.88; P=0.008), longer OLV duration (OR, 1.01; 95% CI, 1.0-1.01; P=0.001), and less surgeon's experience (OR, 1.67; 95% CI, 1.03-2.7; P=0.036). When low-tidal-volume cutoff was defined as <8 mL/kg, PEEP level was a protective factor for PPCs (OR, 0.83; 95% CI, 0.69-1.00; P=0.046). Additionally, PPCs were associated with increased hospital stay (P<0.001).

CONCLUSIONS

Male sex, longer OLV duration, less surgeon's experience, and lower PEEP were risk factors of PPCs in children undergoing video-assisted thoracoscopic surgery. Our findings may serve as targets for prospective studies investigating specific ventilation strategies for children.

Association between driving pressure-guided ventilation and postoperative pulmonary complications in surgical patients: a meta-analysis with trial sequential analysis

BACKGROUND

Prior studies have reported inconsistent results regarding the association between driving pressure-guided ventilation and postoperative pulmonary complications (PPCs). We aimed to investigate whether driving pressure-guided ventilation is associated with a lower risk of PPCs.

METHODS

We systematically searched electronic databases for RCTs comparing driving pressure-guided ventilation with conventional protective ventilation in adult surgical patients. The primary outcome was a composite of PPCs. Secondary outcomes were pneumonia, atelectasis, and acute respiratory distress syndrome (ARDS). Meta-analysis and subgroup analysis were conducted to calculate risk ratios (RRs) with 95% confidence intervals (CI). Trial sequential analysis (TSA) was used to assess the conclusiveness of evidence.

RESULTS

Thirteen RCTs with 3401 subjects were included. Driving pressure-guided ventilation was associated with a lower risk of PPCs (RR 0.70, 95% CI 0.56-0.87, P=0.001), as indicated by TSA. Subgroup analysis (P for interaction=0.04) found that the association was observed in non-cardiothoracic surgery (nine RCTs, 1038 subjects, RR 0.61, 95% CI 0.48-0.77, P< 0.0001), with TSA suggesting sufficient evidence and conclusive result; however, it did not reach significance in cardiothoracic surgery (four RCTs, 2363 subjects, RR 0.86, 95% CI 0.67-1.10, P=0.23), with TSA indicating insufficient evidence and inconclusive result. Similarly, a lower risk of pneumonia was found in non-cardiothoracic surgery but not in cardiothoracic surgery (P for interaction=0.046). No significant differences were found in atelectasis and ARDS between the two ventilation strategies.

CONCLUSIONS

Driving pressure-guided ventilation was associated with a lower risk of postoperative pulmonary complications in non-cardiothoracic surgery but not in cardiothoracic surgery.

SYSTEMATIC REVIEW PROTOCOL

INPLASY 202410068.

Impaired oxygenation after lung resection: Incidence and perioperative risk factors

STUDY OBJECTIVE

To estimate the incidence of postoperative oxygenation impairment after lung resection in the era of lung-protective management, and to identify perioperative factors associated with that impairment.

DESIGN

Registry-based retrospective cohort study.

SETTING

Two large academic hospitals in the United States.

PATIENTS

3081 ASA I-IV patients undergoing lung resection.

MEASUREMENTS

79 pre- and intraoperative variables, selected for inclusion based on a causal inference framework. The primary outcome of impaired oxygenation, an early marker of lung injury, was defined as at least one of the following within seven postoperative days: (1) SpO2 < 92%; (2) imputed PaO2/FiO2 < 300 mmHg [(1) or (2) occurring at least twice within 24 h]; (3) intensive oxygen therapy (mechanical ventilation or > 50% oxygen or high-flow oxygen).

MAIN RESULTS

Oxygenation was impaired within seven postoperative days in 70.8% of patients (26.6% with PaO2/FiO2 < 200 mmHg or intensive oxygen therapy). In multivariable analysis, each additional cmH2O of intraoperative median driving pressure was associated with a 7% higher risk of impaired oxygenation (OR 1.07; 95%CI 1.04 to 1.10). Higher median intraoperative FiO2 (OR 1.23; 95%CI 1.14 to 1.31 per 0.1) and PEEP (OR 1.12; 95%CI 1.04 to 1.21 per 1 cm H2O) were also associated with increased risk. History of COPD (OR 2.55; 95%CI 1.95 to 3.35) and intraoperative albuterol administration (OR 2.07; 95%CI 1.17 to 3.67) also showed reliable effects.

CONCLUSIONS

Impaired postoperative oxygenation is common after lung resection and is associated with potentially modifiable pre- and intraoperative respiratory factors.

Effect of flow-optimized pressure control ventilation-volume guaranteed (PCV-VG) on postoperative pulmonary complications: a consort study

BACKGROUND

Postoperative pulmonary complications (PPCs) after one-lung ventilation (OLV) significantly impact patient prognosis and quality of life.

OBJECTIVE

To study the impact of an optimal inspiratory flow rate on PPCs in thoracic surgery patients.

METHODS

One hundred eight elective thoracic surgery patients were randomly assigned to 2 groups in this consort study (control group: n = 53 with a fixed inspiratory expiratory ratio of 1:2; and experimental group [flow rate optimization group]: n = 55). Measurements of Ppeak, Pplat, PETCO2, lung dynamic compliance (Cdyn), respiratory rate, and oxygen concentration were obtained at the following specific time points: immediately after intubation (T0); immediately after starting OLV (T1); 30 min after OLV (T2); and 10 min after 2-lung ventilation (T4). The PaO2:FiO2 ratio was measured using blood gas analysis 30 min after initiating one-lung breathing (T2) and immediately when OLV ended (T3). The lung ultrasound score (LUS) was assessed following anesthesia and resuscitation (T5). The occurrence of atelectasis was documented immediately after the surgery. PPCs occurrences were noted 3 days after surgery.

RESULTS

The treatment group had a significantly lower total prevalence of PPCs compared to the control group (3.64% vs. 16.98%; P = 0.022). There were no notable variations in peak airway pressure, airway plateau pressure, dynamic lung compliance, PETCO2, respiratory rate, and oxygen concentration between the two groups during intubation (T0). Dynamic lung compliance and the oxygenation index were significantly increased at T1, T2, and T4 (P < 0.05), whereas the CRP level and number of inflammatory cells decreased dramatically (P < 0.05).

CONCLUSION

Optimizing inspiratory flow rate and utilizing pressure control ventilation -volume guaranteed (PCV-VG) mode can decrease PPCs and enhance lung dynamic compliance in OLV patients.

Association of Mechanical Energy and Power with Postoperative Pulmonary Complications in Lung Resection Surgery: A Post Hoc Analysis of Randomized Clinical Trial Data

BACKGROUND

Mechanical power (MP), the rate of mechanical energy (ME) delivery, is a recently introduced unifying ventilator parameter consisting of tidal volume, airway pressures, and respiratory rates, which predicts pulmonary complications in several clinical contexts. However, ME has not been previously studied in the perioperative context, and neither parameter has been studied in the context of thoracic surgery utilizing one-lung ventilation.

METHODS

The relationships between ME variables and postoperative pulmonary complications were evaluated in this post hoc analysis of data from a multicenter randomized clinical trial of lung resection surgery conducted between 2020 and 2021 (n = 1,170). Time-weighted average MP and ME (the area under the MP time curve) were obtained for individual patients. The primary analysis was the association of time-weighted average MP and ME with pulmonary complications within 7 postoperative days. Multivariable logistic regression was performed to examine the relationships between energy variables and the primary outcome.

RESULTS

In 1,055 patients analyzed, pulmonary complications occurred in 41% (431 of 1,055). The median (interquartile ranges) ME and time-weighted average MP in patients who developed postoperative pulmonary complications versus those who did not were 1,146 (811 to 1,530) J versus 924 (730 to 1,240) J (P < 0.001), and 6.9 (5.5 to 8.7) J/min versus 6.7 (5.2 to 8.5) J/min (P = 0.091), respectively. ME was independently associated with postoperative pulmonary complications (ORadjusted, 1.44 [95% CI, 1.16 to 1.80]; P = 0.001). However, the association between time-weighted average MP and postoperative pulmonary complications was time-dependent, and time-weighted average MP was significantly associated with postoperative pulmonary complications in cases utilizing longer periods of mechanical ventilation (210 min or greater; ORadjusted, 1.46 [95% CI, 1.11 to 1.93]; P = 0.007). Normalization of ME and time-weighted average MP either to predicted body weight or to respiratory system compliance did not alter these associations.

CONCLUSIONS

ME and, in cases requiring longer periods of mechanical ventilation, MP were independently associated with postoperative pulmonary complications in thoracic surgery.

EDITOR’S PERSPECTIVE

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.

Effect of incremental PEEP titration on postoperative pulmonary complications in patients undergoing emergency laparotomy: a randomized controlled trial

Postoperative pulmonary complications (PPC) has a significant negative impact and are associated with increased length of hospital stay and cost of care. Emergency surgery is a well-established risk factor for PPC. Previous studies reported that personalized positive end-expiratory pressure (PEEP) might reduce postoperative atelectasis and postoperative pulmonary complications. N = 168 adult patients undergoing major emergency laparotomy under general anesthesia were recruited in this study. A minimum driving pressure based incremental PEEP titration was compared to a fixed PEEP of 5 cmH2O. The primary outcome was PPC up to postoperative day 7. The mean (standard deviation) of the recruited patients was 41.7(16.1)y, and 48.8% (82 of 168 patients) were female. The risk of PPC at postoperative day 7 was similar in both the study groups [Relative risk (RR) (95% Confidence interval, CI) 0.81 (0.58, 1.13); p = 0.25]. In addition, the incidence of intraoperative hypotension [p = 0.75], oxygen-free days at day 28 [p = 0.27], duration of postoperative hospital stay [p = 0.50], length of postoperative intensive care unit stay [p = 0.28], and in-hospital mortality [p = 0.38] were similar in two groups. Incidence of PPC was not reduced with the use of an individualized PEEP strategy based on lowest driving pressure. However, the incidence of hypotension and bradycardia was also not increased with titrated PEEP.Trial Registration: www.ctri.nic.in ; CTRI/2020/12/029765.

Driving pressure in mechanical ventilation: A review

Driving pressure (∆P) is a core therapeutic component of mechanical ventilation (MV). Varying levels of ∆P have been employed during MV depending on the type of underlying pathology and severity of injury. However, ∆P levels have also been shown to closely impact hard endpoints such as mortality. Considering this, conducting an in-depth review of ∆P as a unique, outcome-impacting therapeutic modality is extremely important. There is a need to understand the subtleties involved in making sure ∆P levels are optimized to enhance outcomes and minimize harm. We performed this narrative review to further explore the various uses of ∆P, the different parameters that can affect its use, and how outcomes vary in different patient populations at different pressure levels. To better utilize ∆P in MV-requiring patients, additional large-scale clinical studies are needed.

Individualised, perioperative open-lung ventilation strategy during one-lung ventilation (iPROVE-OLV): a multicentre, randomised, controlled clinical trial

BACKGROUND

It is uncertain whether individualisation of the perioperative open-lung approach (OLA) to ventilation reduces postoperative pulmonary complications in patients undergoing lung resection. We compared a perioperative individualised OLA (iOLA) ventilation strategy with standard lung-protective ventilation in patients undergoing thoracic surgery with one-lung ventilation.

METHODS

This multicentre, randomised controlled trial enrolled patients scheduled for open or video-assisted thoracic surgery using one-lung ventilation in 25 participating hospitals in Spain, Italy, Turkey, Egypt, and Ecuador. Eligible adult patients (age ≥18 years) were randomly assigned to receive iOLA or standard lung-protective ventilation. Eligible patients (stratified by centre) were randomly assigned online by local principal investigators, with an allocation ratio of 1:1. Treatment with iOLA included an alveolar recruitment manoeuvre to 40 cm H2O of end-inspiratory pressure followed by individualised positive end-expiratory pressure (PEEP) titrated to best respiratory system compliance, and individualised postoperative respiratory support with high-flow oxygen therapy. Participants allocated to standard lung-protective ventilation received combined intraoperative 4 cm H2O of PEEP and postoperative conventional oxygen therapy. The primary outcome was a composite of severe postoperative pulmonary complications within the first 7 postoperative days, including atelectasis requiring bronchoscopy, severe respiratory failure, contralateral pneumothorax, early extubation failure (rescue with continuous positive airway pressure, non-invasive ventilation, invasive mechanical ventilation, or reintubation), acute respiratory distress syndrome, pulmonary infection, bronchopleural fistula, and pleural empyema. Due to trial setting, data obtained in the operating and postoperative rooms for routine monitoring were not blinded. At 24 h, data were acquired by an investigator blinded to group allocation. All analyses were performed on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, NCT03182062, and is complete.

FINDINGS

Between Sept 11, 2018, and June 14, 2022, we enrolled 1380 patients, of whom 1308 eligible patients (670 [434 male, 233 female, and three with missing data] assigned to iOLA and 638 [395 male, 237 female, and six with missing data] to standard lung-protective ventilation) were included in the final analysis. The proportion of patients with the composite outcome of severe postoperative pulmonary complications within the first 7 postoperative days was lower in the iOLA group compared with the standard lung-protective ventilation group (40 [6%] vs 97 [15%], relative risk 0·39 [95% CI 0·28 to 0·56]), with an absolute risk difference of -9·23 (95% CI -12·55 to -5·92). Recruitment manoeuvre-related adverse events were reported in five patients.

INTERPRETATION

Among patients subjected to lung resection under one-lung ventilation, iOLA was associated with a reduced risk of severe postoperative pulmonary complications when compared with conventional lung-protective ventilation.

FUNDING

Instituto de Salud Carlos III and the European Regional Development Funds.

Update on guidelines and recommendations for enhanced recovery after thoracic surgery

PURPOSE OF REVIEW

Enhanced recovery after thoracic surgery (ERATS) has continued its growth in popularity over the past few years, and evidence for its utility is catching up to other specialties. This review will present and examine some of that accumulated evidence since guidelines sponsored by the Enhanced Recovery after Surgery (ERAS) Society and the European Society of Thoracic Surgeons (ESTS) were first published in 2019.

RECENT FINDINGS

The ERAS/ESTS guidelines published in 2019 have not been updated, but new studies have been done and new data has been published regarding some of the individual components of the guidelines as they relate to thoracic and lung resection surgery. While there is still not a consensus on many of these issues, the volume of available evidence is becoming more robust, some of which will be incorporated into this review.

SUMMARY

The continued accumulation of data and evidence for the benefits of enhanced recovery techniques in thoracic and lung resection surgery will provide the thoracic anesthesiologist with guidance on how to best care for these patients before, during, and after surgery. The data from these studies will also help to elucidate which components of ERAS protocols are the most beneficial, and which components perhaps do not provide as much benefit as previously thought.

Effects of individualized positive end-expiratory pressure on intraoperative oxygenation in thoracic surgical patients: study protocol for a prospective randomized controlled trial

BACKGROUND

Intraoperative hypoxemia and postoperative pulmonary complications (PPCs) often occur in patients with one-lung ventilation (OLV), due to both pulmonary shunt and atelectasis. It has been demonstrated that individualized positive end-expiratory pressure (iPEEP) can effectively improve intraoperative oxygenation, increase lung compliance, and reduce driving pressure, thereby decreasing the risk of developing PPCs. However, its effect during OLV is still unknown. Therefore, we aim to investigate whether iPEEP ventilation during OLV is superior to 5 cmH2O PEEP in terms of intraoperative oxygenation and the occurrence of PPCs.

METHODS

This study is a prospective, randomized controlled, single-blind, single-center trial. A total of 112 patients undergoing thoracoscopic pneumonectomy surgery and OLV will be enrolled in the study. They will be randomized into two groups: the static lung compliance guided iPEEP titration group (Cst-iPEEP Group) and the constant 5 cmH2O PEEP group (PEEP 5 Group). The primary outcome will be the oxygenation index at 30 min after OLV and titration. Secondary outcomes are oxygenation index at other operative time points, PPCs, postoperative adverse events, ventilator parameters, vital signs, pH value, inflammatory factors, and economic indicators.

DISCUSSION

This trial explores the effect of iPEEP on intraoperative oxygenation during OLV and PPCs. It provides some clinical references for optimizing the lung protective ventilation strategy of OLV, improving patient prognosis, and accelerating postoperative rehabilitation.

TRIAL REGISTRATION

www.Chictr.org.cn ChiCTR2300073411 . Registered on 10 July 2023.

Positive end-expiratory pressure during one-lung ventilation for preventing atelectasis after video-assisted thoracoscopic surgery: a triple-arm, randomized controlled trial

BACKGROUND

There is little evidence regarding the benefits of lung-protective ventilation in patients undergoing one-lung ventilation for thoracic surgery. This study aimed to determine the optimal level of positive end-expiratory pressure (PEEP) during one-lung ventilation for minimizing postoperative atelectasis through lung ultrasonography.

METHODS

A total of 142 adult patients scheduled for video-assisted thoracoscopic surgery at Seoul National University Hospital between May 2019 and February 2020 were enrolled in this study. Patients were randomly assigned to different groups: 1) PEEP 3 cmH2O group; 2) PEEP 6 cmH2O group; and 3) PEEP 9 cmH2O group during one-lung ventilation. The lung ultrasound score was used to evaluate lung aeration using ultrasonography 1 hour after surgery.

RESULTS

The 1-hour post-surgery lung ultrasound scores were 8.1±2.5, 6.8±2.6, and 5.9±2.6 in the PEEP 3, 6, and 9 cmH2O groups, respectively (P<0.001). The PEEP 3 cmH2O group showed significantly higher lung ultrasound scores than the PEEP 6 (adjusted P=0.034) and 9 cmH2O groups (adjusted P<0.001). The PaO2/FiO2 ratio measured at 10 minutes after the end of one-lung ventilation was significantly lower in the PEEP 3 cmH2O group (392 [331 to 469]) than the PEEP 6 cmH2O (458 [384 to 530], adjusted P=0.018) or PEEP 9 cmH2O groups (454 [374 to 522], adjusted P=0.016).

CONCLUSIONS

Although the optimal level of PEEP during one-lung ventilation was not determined, the application of higher PEEP can prevent aeration loss in the ventilated lung after video-assisted thoracoscopic surgery under one-lung ventilation.

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.

Perioperative considerations for patients undergoing surgical stabilization of rib fractures: A narrative review

Surgical stabilization of rib fractures (SSRF) has become an increasingly common management strategy for traumatic rib fractures. Although historically managed with supportive care, patients with multiple rib fractures and flail chest increasingly undergo SSRF, and so the anesthesiologist must be well-versed in the perioperative management and pain control for these patients, as controlling pain in this population is associated with decreased length of stay and improved outcomes. There are multiple modalities that can be used for both pain control and as part of the anesthetic plan in patients undergoing SSRF. This narrative review provides a comprehensive summary of anesthetic considerations for surgical rib fracture patients, covering the preoperative, intraoperative, and postoperative periods. We describe an approach to the assessment of high-risk patients, analgesic and anesthetic techniques including emerging techniques within locoregional anesthesia, ventilation strategies, and potential complications. This review also identifies areas where additional research is needed to ensure optimal anesthetic management for patients undergoing SSRF.

One-Lung Ventilation and Postoperative Pulmonary Complications After Major Lung Resection Surgery. A Multicenter Randomized Controlled Trial

OBJECTIVES

The effect of one-lung ventilation (OLV) strategy based on low tidal volume (TV), application of positive end-expiratory pressure (PEEP), and alveolar recruitment maneuvers (ARM) to reduce postoperative acute respiratory distress syndrome (ARDS) and pulmonary complications (PPCs) compared with higher TV without PEEP and ARM strategy in adult patients undergoing lobectomy or pneumonectomy has not been well established.

DESIGN

Multicenter, randomized, single-blind, controlled trial.

SETTING

Sixteen Italian hospitals.

PARTICIPANTS

A total of 880 patients undergoing elective major lung resection.

INTERVENTIONS

Patients were randomized to receive lower tidal volume (LTV group: 4 mL/kg predicted body weight, PEEP of 5 cmH2O, and ARMs) or higher tidal volume (HTL group: 6 mL/kg predicted body weight, no PEEP, and no ARMs). After OLV, until extubation, both groups were ventilated using a tidal volume of 8 mL/kg and a PEEP value of 5 cmH2O. The primary outcome was the incidence of in-hospital ARDS. Secondary outcomes were the in-hospital rate of PPCs, major cardiovascular events, unplanned intensive care unit (ICU) admission, in-hospital mortality, ICU length of stay, and in-hospital length of stay.

MEASUREMENTS AND MAIN RESULTS

ARDS occurred in 3 of 438 patients (0.7%, 95% CI 0.1-2.0) and in 1 of 442 patients (0.2%, 95% CI 0-1.4) in the LTV and HTV group, respectively (Risk ratio: 3.03 95% CI 0.32-29, p = 0.372). Pulmonary complications occurred in 125 of 438 patients (28.5%, 95% CI 24.5-32.9) and in 136 of 442 patients (30.8%, 95% CI 26.6-35.2) in the LTV and HTV group, respectively (risk ratio: 0.93, 95% CI 0.76-1.14, p = 0.507). The incidence of major complications, in-hospital mortality, and unplanned ICU admission, ICU and in-hospital length of stay were comparable in both groups.

CONCLUSIONS

In conclusion, among adult patients undergoing elective lung resection, an OLV with lower tidal volume, PEEP 5 cmH2O, and ARMs and a higher tidal volume strategy resulted in low ARDS incidence and comparable postoperative complications, in-hospital length of stay, and mortality.

Association of mechanical power during one-lung ventilation and post-operative pulmonary complications among patients undergoing lobectomy: a protocol for a prospective cohort study

The association of intra-operative mechanical power (MP) with post-operative pulmonary complications (PPCs) has been described before, but it is uncertain whether the potential inherent bias can limit the use of this parameter, particularly in the context of one-lung ventilation. This single-center study aims to investigate the effect of MP during one-lung ventilation (OLV), and the risks of PPCs in patients undergoing thoracoscopic lobectomy. This prospective observational study is being conducted in an academic tertiary hospital in mainland China. Participants diagnosed with lung cancer, and aged 50 to 80 years are eligible. Video-assisted thoracoscopic surgery (VATS) lobectomy is performed for all patients. The primary outcome is the occurrence of PPCs over 5 consecutive days after the surgery, or until discharge from the hospital. Secondary outcomes include the composite conditions of PPCs, in-hospital stay, systematic inflammation tested by blood samples, and changes in aeration compartments in the ventilated lung as assessed by CT scans. We aim to evaluate the association of mean MP and the temporal patterns in the trend of MP during OLV with the occurrence of PPCs. A total of 120 patients will be enrolled in this study. The study protocol has received approval from the Ethics Committee of the affiliated hospital of Southwest Medical University, China (Reference number: KY2022162). The findings will be made available to the funder and researchers via scientific conferences and peer-reviewed publications. This controlled trial was approved by the Ethics Committee of Southwest Medical University(ChiCTR2200062173), and registered in the Chinese Clinical Trial Register website ( http://www.chictr.org.cn/edit.aspx?pid=172533&htm=4 , ChiCTR2200062173). A written consent was obtained from each patient.

Effect of driving pressure-guided positive end-expiratory pressure on postoperative pulmonary complications in patients undergoing laparoscopic or robotic surgery: a randomised controlled trial

BACKGROUND

Individualised positive end-expiratory pressure (PEEP) improves respiratory mechanics. However, whether PEEP reduces postoperative pulmonary complications (PPCs) remains unclear. We investigated whether driving pressure-guided PEEP reduces PPCs after laparoscopic/robotic abdominal surgery.

METHODS

This single-centre, randomised controlled trial enrolled patients at risk for PPCs undergoing laparoscopic or robotic lower abdominal surgery. The individualised group received driving pressure-guided PEEP, whereas the comparator group received 5 cm H2O fixed PEEP during surgery. Both groups received a tidal volume of 8 ml kg-1 ideal body weight. The primary outcome analysed per protocol was a composite of pulmonary complications (defined by pre-specified clinical and radiological criteria) within 7 postoperative days after surgery.

RESULTS

Some 384 patients (median age: 67 yr [inter-quartile range: 61-73]; 66 [18%] female) were randomised. Mean (standard deviation) PEEP in patients randomised to individualised PEEP (n=178) was 13.6 cm H2O (2.1). Individualised PEEP resulted in lower mean driving pressures (14.7 cm H2O [2.6]), compared with 185 patients randomised to standard PEEP (18.4 cm H2O [3.2]; mean difference: -3.7 cm H2O [95% confidence interval (CI): -4.3 to -3.1 cm H2O]; P<0.001). There was no difference in the incidence of pulmonary complications between individualised (25/178 [14.0%]) vs standard PEEP (36/185 [19.5%]; risk ratio [95% CI], 0.72 [0.45-1.15]; P=0.215). Pulmonary complications as a result of desaturation were less frequent in patients randomised to individualised PEEP (8/178 [4.5%], compared with standard PEEP (30/185 [16.2%], risk ratio [95% CI], 0.28 [0.13-0.59]; P=0.001).

CONCLUSIONS

Driving pressure-guided PEEP did not decrease the incidence of pulmonary complications within 7 days of laparoscopic or robotic lower abdominal surgery, although uncertainty remains given the lower than anticipated event rate for the primary outcome.

CLINICAL TRIAL REGISTRATION

KCT0004888 (http://cris.nih.go.kr, registration date: April 6, 2020).

Minimizing Lung Injury During Laparoscopy in Head-Down Tilt: A Physiological Cohort Study

BACKGROUND

Increased intra-abdominal pressure during laparoscopy induces atelectasis. Positive end-expiratory pressure (PEEP) can alleviate atelectasis but may cause hyperinflation. Cyclic opening of collapsed alveoli and hyperinflation can lead to ventilator-induced lung injury and postoperative pulmonary complications. We aimed to study the effect of PEEP on atelectasis, lung stress, and hyperinflation during laparoscopy in the head-down (Trendelenburg) position.

METHODS

An open-label, repeated-measures, interventional, physiological cohort trial was designed. All participants were recruited from a single tertiary Belgian university hospital. Twenty-three nonobese patients scheduled for laparoscopy in the Trendelenburg position were recruited.We applied a decremental PEEP protocol: 15 (high), 10 and 5 (low) cm H 2 O. Atelectasis was studied with the lung ultrasound score, the end-expiratory transpulmonary pressure, the arterial oxygen partial pressure to fraction of inspired oxygen concentration (P ao2 /Fi o2 ) ratio, and the dynamic respiratory system compliance. Global hyperinflation was evaluated by dead space volume, and regional ventilation was evaluated by lung ultrasound. Lung stress was estimated using the transpulmonary driving pressure and dynamic compliance. Data are reported as medians (25th-75th percentile).

RESULTS

At 15, 10, and 5 cm H 2 O PEEP, the respective measurements were: lung ultrasound scores (%) 11 (0-22), 27 (11-39), and 53 (42-61) ( P < .001); end-expiratory transpulmonary pressures (cm H 2 O) 0.9 (-0.6 to 1.7), -0.3 (-2.0 to 0.7), and -1.9 (-4.6 to -0.9) ( P < .001); P ao2 /Fi o2 ratios (mm Hg) 471 (435-538), 458 (410-537), and 431 (358-492) ( P < .001); dynamic respiratory system compliances (mL/cm H 2 O) 32 (26-36), 30 (25-34), and 27 (22-30) ( P < .001); driving pressures (cm H 2 O) 8.2 (7.5-9.5), 9.3 (8.5-11.1), and 11.0 (10.3-12.2) ( P < .001); and alveolar dead space ventilation fractions (%) 10 (9-12), 10 (9-12), and 9 (8-12) ( P = .23). The lung ultrasound score was similar between apical and basal lung regions at each PEEP level ( P = .76, .37, and .76, respectively).

CONCLUSIONS

Higher PEEP levels during laparoscopy in the head-down position facilitate lung-protective ventilation. Atelectasis and lung stress are reduced in the absence of global alveolar hyperinflation.

Intensity of one-lung ventilation and postoperative respiratory failure: A hospital registry study

BACKGROUND

Studies linked a high intensity of mechanical ventilation, measured as high mechanical power (MP) to postoperative respiratory failure (PRF) in the setting of two-lung ventilation. We investigated whether a higher MP during one-lung ventilation (OLV) is associated with PRF.

METHODS

In this registry-based study, adult patients who underwent general anesthesia with OLV for thoracic surgeries between 2006 and 2020 at a New England tertiary healthcare network were included. The association between MP during OLV and PRF (emergency non-invasive ventilation or reintubation within seven days) was assessed in a cohort weighted through a generalized propensity score conditional on a priori defined preoperative and intraoperative factors. Dominance of components of MP and intensity of OLV versus two-lung ventilation in predicting PRF was investigated.

RESULTS

Out of 878 included patients, 106 (12.1%) developed PRF. The median (IQR) MP during OLV was 9.8 J/min (7.5-11.8) and 8.3 J/min (6.6-10.2) in patients with and without PRF respectively. A higher MP during OLV was associated with PRF (ORadj 1.22 per 1 J/min increase; 95%CI 1.13-1.31; p < 0.001) and characterized by a U-shaped dose-response curve, with the lowest probability of PRF (7.5%) at 6.4 J/min. Dominance analysis of PRF predictors showed a stronger contribution of driving pressure over respiratory rate and tidal volume, the dynamic over the static component of MP, and MP during OLV over two-lung ventilation (contribution to Pseudo-R2: 0.017, 0.021, and 0.036, respectively).

CONCLUSION

A higher intensity of OLV, mainly driven by driving pressure, is dose-dependently associated with PRF and might constitute a target for mechanical ventilation.

The effect of driving pressure-guided versus conventional mechanical ventilation strategy on pulmonary complications following on-pump cardiac surgery: A randomized clinical trial

STUDY OBJECTIVE

Postoperative pulmonary complications occur frequently and are associated with worse postoperative outcomes in cardiac surgical patients. The advantage of driving pressure-guided ventilation strategy in decreasing pulmonary complications remains to be definitively established. We aimed to investigate the effect of intraoperative driving pressure-guided ventilation strategy compared with conventional lung-protective ventilation on pulmonary complications following on-pump cardiac surgery.

DESIGN

Prospective, two-arm, randomized controlled trial.

SETTING

The West China university hospital in Sichuan, China.

PATIENTS

Adult patients who were scheduled for elective on-pump cardiac surgery were enrolled in the study.

INTERVENTIONS

Patients undergoing on-pump cardiac surgery were randomized to receive driving pressure-guided ventilation strategy based on positive end-expiratory pressure (PEEP) titration or conventional lung-protective ventilation strategy with fixed 5 cmH2O of PEEP.

MEASUREMENTS

The primary outcome of pulmonary complications (including acute respiratory distress syndrome, atelectasis, pneumonia, pleural effusion, and pneumothorax) within the first 7 postoperative days were prospectively identified. Secondary outcomes included pulmonary complication severity, ICU length of stay, and in-hospital and 30-day mortality.

MAIN RESULTS

Between August 2020 and July 2021, we enrolled 694 eligible patients who were included in the final analysis. Postoperative pulmonary complications occurred in 140 (40.3%) patients in the driving pressure group and 142 (40.9%) in the conventional group (relative risk, 0.99; 95% confidence interval, 0.82-1.18; P = 0.877). Intention-to-treat analysis showed no significant difference between study groups regarding the incidence of primary outcome. The driving pressure group had less atelectasis than the conventional group (11.5% vs 17.0%; relative risk, 0.68; 95% confidence interval, 0.47-0.98; P = 0.039). Secondary outcomes did not differ between groups.

CONCLUSION

Among patients who underwent on-pump cardiac surgery, the use of driving pressure-guided ventilation strategy did not reduce the risk of postoperative pulmonary complications when compared with conventional lung-protective ventilation strategy.

Effect of intravenous vs. inhaled penehyclidine on respiratory mechanics in patients during one-lung ventilation for thoracoscopic surgery: a prospective, double-blind, randomised controlled trial

BACKGROUND

Minimising postoperative pulmonary complications (PPCs) after thoracic surgery is of utmost importance. A major factor contributing to PPCs is the driving pressure, which is determined by the ratio of tidal volume to lung compliance. Inhalation and intravenous administration of penehyclidine can improve lung compliance during intraoperative mechanical ventilation. Therefore, our study aimed to compare the efficacy of inhaled vs. intravenous penehyclidine during one-lung ventilation (OLV) in mitigating driving pressure and mechanical power among patients undergoing thoracic surgery.

METHODS

A double-blind, prospective, randomised study involving 176 patients scheduled for elective thoracic surgery was conducted. These patients were randomly divided into two groups, namely the penehyclidine inhalation group and the intravenous group before their surgery. Driving pressure was assessed at T1 (5 min after OLV), T2 (15 min after OLV), T3 (30 min after OLV), and T4 (45 min after OLV) in both groups. The primary outcome of this study was the composite measure of driving pressure during OLV. The area under the curve (AUC) of driving pressure from T1 to T4 was computed. Additionally, the secondary outcomes included mechanical power, lung compliance and the incidence of PPCs.

RESULTS

All 167 participants, 83 from the intravenous group and 84 from the inhalation group, completed the trial. The AUC of driving pressure for the intravenous group was 39.50 ± 9.42, while the inhalation group showed a value of 41.50 ± 8.03 (P = 0.138). The incidence of PPCs within 7 days after surgery was 27.7% in the intravenous group and 23.8% in the inhalation group (P = 0.564). No significant differences were observed in any of the other secondary outcomes between the two groups (all P > 0.05).

CONCLUSIONS

Our study found that among patients undergoing thoracoscopic surgery, no significant differences were observed in the driving pressure and mechanical power during OLV between those who received an intravenous injection of penehyclidine and those who inhaled it. Moreover, no significant difference was observed in the incidence of PPCs between the two groups.

Individualized Positive End-expiratory Pressure on Postoperative Atelectasis in Patients with Obesity: A Randomized Controlled Clinical Trial

BACKGROUND

Individualized positive end-expiratory pressure (PEEP) guided by dynamic compliance improves oxygenation and reduces postoperative atelectasis in nonobese patients. The authors hypothesized that dynamic compliance-guided PEEP could also reduce postoperative atelectasis in patients undergoing bariatric surgery.

METHODS

Patients scheduled to undergo laparoscopic bariatric surgery were eligible. Dynamic compliance-guided PEEP titration was conducted in all patients using a downward approach. A recruitment maneuver (PEEP from 10 to 25 cm H2O at 5-cm H2O step every 30 s, with 15-cm H2O driving pressure) was conducted both before and after the titration. Patients were then randomized (1:1) to undergo surgery under dynamic compliance-guided PEEP (PEEP with highest dynamic compliance plus 2 cm H2O) or PEEP of 8 cm H2O. The primary outcome was postoperative atelectasis, as assessed with computed tomography at 60 to 90 min after extubation, and expressed as percentage to total lung tissue volume. Secondary outcomes included Pao2/inspiratory oxygen fraction (Fio2) and postoperative pulmonary complications.

RESULTS

Forty patients (mean ± SD; 28 ± 7 yr of age; 25 females; average body mass index, 41.0 ± 4.7 kg/m2) were enrolled. Median PEEP with highest dynamic compliance during titration was 15 cm H2O (interquartile range, 13 to 17; range, 8 to 19) in the entire sample of 40 patients. The primary outcome of postoperative atelectasis (available in 19 patients in each group) was 13.1 ± 5.3% and 9.5 ± 4.3% in the PEEP of 8 cm H2O and dynamic compliance-guided PEEP groups, respectively (intergroup difference, 3.7%; 95% CI, 0.5 to 6.8%; P = 0.025). Pao2/Fio2 at 1 h after pneumoperitoneum was higher in the dynamic compliance-guided PEEP group (397 vs. 337 mmHg; group difference, 60; 95% CI, 9 to 111; P = 0.017) but did not differ between the two groups 30 min after extubation (359 vs. 375 mmHg; group difference, -17; 95% CI, -53 to 21; P = 0.183). The incidence of postoperative pulmonary complications was 4 of 20 in both groups.

CONCLUSIONS

Postoperative atelectasis was lower in patients undergoing laparoscopic bariatric surgery under dynamic compliance-guided PEEP versus PEEP of 8 cm H2O. Postoperative Pao2/Fio2 did not differ between the two groups.

EDITOR’S PERSPECTIVE

Secondary analysis of preoperative predictors for acute postoperative exacerbation in interstitial lung disease

This study assessed whether perioperative management is associated with postoperative acute exacerbations (AEs) in interstitial lung disease (ILD) patients. Using secondary data from the study "Postoperative acute exacerbation of interstitial lung disease: a case-control study," we compared the perioperative clinical management of the AE and non-AE groups (1:4 case-control matching) selected by sex, year of surgery (2009-2011, 2012-2014, and 2015-2017), and multiple surgeries within 30 days. We compared 27 and 108 patients with and without AEs, respectively. Rates of one lung ventilation (OLV) cases (70 vs. 29%; OR, 5.9; 95%CI, 2.34-14.88; p < 0.001) and intraoperative steroid administration (48 vs. 26%; OR, 2.65; 95%CI, 1.11-6.33; p = 0.028), and average mean inspiratory pressure (9.2 [1.8] vs. 8.3 [1.7] cmH2O; OR, 1.36; 95%CI, 1.04-1.79; p = 0.026), were significantly higher in the AE group. There was a significant difference in OLV between the groups (OR, 4.99; 95%CI, 1.90-13.06; p = 0.001). However, the fraction of inspired oxygen  > 0.8 lasting > 1 min (63 vs. 73%, p = 0.296) was not significantly different between the groups. OLV was significantly associated with postoperative AEs in patients with ILD undergoing both pulmonary and non-pulmonary surgeries. Thus, preoperative risk considerations are more important in patients who require OLV.

Dynamic lung aeration and strain with positive end-expiratory pressure individualized to maximal compliance versus ARDSNet low-stretch strategy: a study in a surfactant depletion model of lung injury

BACKGROUND

Positive end-expiratory pressure (PEEP) individualized to a maximal respiratory system compliance directly implies minimal driving pressures with potential outcome benefits, yet, raises concerns on static and dynamic overinflation, strain and cyclic recruitment. Detailed accurate assessment and understanding of these has been hampered by methodological limitations. We aimed to investigate the effects of a maximal compliance-guided PEEP strategy on dynamic lung aeration, strain and tidal recruitment using current four-dimensional computed tomography (CT) techniques and analytical methods of tissue deformation in a surfactant depletion experimental model of acute respiratory distress syndrome (ARDS).

METHODS

ARDS was induced by saline lung lavage in anesthetized and mechanically ventilated healthy sheep (n = 6). Animals were ventilated in a random sequence with: (1) ARDSNet low-stretch protocol; (2) maximal compliance PEEP strategy. Lung aeration, strain and tidal recruitment were acquired with whole-lung respiratory-gated high-resolution CT and quantified using registration-based techniques.

RESULTS

Relative to the ARDSNet low-stretch protocol, the maximal compliance PEEP strategy resulted in: (1) improved dynamic whole-lung aeration at end-expiration (0.456 ± 0.064 vs. 0.377 ± 0.101, P = 0.019) and end-inspiration (0.514 ± 0.079 vs. 0.446 ± 0.083, P = 0.012) with reduced non-aerated and increased normally-aerated lung mass without associated hyperinflation; (2) decreased aeration heterogeneity at end-expiration (coefficient of variation: 0.498 ± 0.078 vs. 0.711 ± 0.207, P = 0.025) and end-inspiration (0.419 ± 0.135 vs. 0.580 ± 0.108, P = 0.014) with higher aeration in dorsal regions; (3) tidal aeration with larger inspiratory increases in normally-aerated and decreases in poorly-aerated areas, and negligible in hyperinflated lung (Aeration × Strategy: P = 0.026); (4) reduced tidal strains in lung regions with normal-aeration (Aeration × Strategy: P = 0.047) and improved regional distributions with lower tidal strains in middle and ventral lung (Region-of-interest [ROI] × Strategy: P < 0.001); and (5) less tidal recruitment in middle and dorsal lung (ROI × Strategy: P = 0.044) directly related to whole-lung tidal strain (r = 0.751, P = 0.007).

CONCLUSIONS

In well-recruitable ARDS models, a maximal compliance PEEP strategy improved end-expiratory/inspiratory whole-lung aeration and its homogeneity without overinflation. It further reduced dynamic strain in middle-ventral regions and tidal recruitment in middle-dorsal areas. These findings suggest the maximal compliance strategy minimizing whole-lung dynamically quantified mechanisms of ventilator-induced lung injury with less cyclic recruitment and no additional overinflation in large heterogeneously expanded and recruitable lungs.

Intraoperative Factors Modifying the Risk of Postoperative Pulmonary Complications After Living Donor Liver Transplantation

BACKGROUND

The relationship between intraoperative anesthetic management and postoperative pulmonary complications (PPCs) after liver transplantation is not fully understood. We aimed to determine the intraoperative contributors to PPC.

METHODS

The retrospectively collected cohort included 605 patients who underwent living donor liver transplantation. PPCs comprised respiratory failure, respiratory infection, pulmonary edema, atelectasis (at least moderate degree), pneumothorax, and pleural effusion (at least moderate degree). The presence and type of PPC were evaluated by 2 pulmonary physicians. Logistic regression analysis was performed to determine the association between perioperative variables and PPC risk.

RESULTS

Of the 605 patients, 318 patients (52.6%) developed 486 PPCs. Multivariable analysis demonstrated that PPC risk decreased with low tidal volume ventilation (odds ratio [OR] 0.62 [0.41-0.94], P  = 0.023) and increased with greater driving pressure at the end of surgery (OR 1.08 [1.01-1.14], P  = 0.018), prolonged hypotension (OR 1.85 [1.27-2.70], P  = 0.001), and blood albumin level ≤3.0 g/dL at the end of surgery (OR 2.43 [1.51-3.92], P  < 0.001). Survival probability at 3, 6, and 12 mo after transplantation was 91.2%, 89.6%, and 86.5%, respectively, in patients with PPCs and 98.3%, 96.5%, and 93.4%, respectively, in patients without PPCs (hazard ratio 2.2 [1.3-3.6], P  = 0.004). Graft survival probability at 3, 6, and 12 mo after transplantation was 89.3%, 87.1%, and 84.3%, respectively, in patients with PPCs and 97.6%, 95.8%, and 92.7%, respectively, in patients without PPCs (hazard ratio 2.3 [1.4-3.7], P  = 0.001).

CONCLUSIONS

We found that tidal volume, driving pressure, hypotension, and albumin level during living donor liver transplantation were significantly associated with PPC risk. These data may help determine patients at risk of PPC or develop an intraoperative lung-protective strategy for liver transplant recipients.

Driving Pressure-Guided Ventilation in Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy: A Randomized Controlled Trial

Purpose

This study aims to compare the conventional lung protective ventilation strategy (LPVS) with driving pressure-guided ventilation in obese patients undergoing laparoscopic sleeve gastrectomy (LSG).

Methods

Forty-five patients undergoing elective LSG under general anesthesia were randomly assigned to the conventional LPVS group (group L) or the driving pressure-guided ventilation group (group D) using random numbers generated by Excel. The primary outcome was the driving pressure of both groups 90 min after pneumoperitoneum.

Results

After 30 min of pneumoperitoneum, 90 min of pneumoperitoneum, 10 min of closing the pneumoperitoneum, and restoring the supine position, the driving pressure of group L and group D were 20.0 ± 2.9 cm H2O vs 16.6 ± 3.0 cm H2O (P < 0.001), 20.7 ± 3.2 cm H2O vs 17.3 ± 2.8 cm H2O (P < 0.001), and 16.3 ± 3.1 cm H2O vs 13.3 ± 2.5 cm H2O (P = 0.001), respectively; the respiratory compliance of groups L and D were 23.4 ± 3.7 mL/cm H2O vs 27.6 ± 5.1 mL/cm H2O (P = 0.003), 22.7 ± 3.8 mL/cm H2O vs 26.4 ± 3.5 mL/cm H2O (P = 0.005), and 29.6 ± 6.8 mL/cm H2O vs 34.7 ± 5.3 mL/cm H2O (P = 0.007), respectively. The intraoperative PEEP in groups L and group D was 5 (5-5) cm H2O vs 10 (9-11) cm H2O (P < 0.001).

Conclusion

An individualized peep-based driving pressure-guided ventilation strategy can reduce intraoperative driving pressure and increase respiratory compliance in obese patients undergoing LSG.

Effect of driving pressure on early postoperative lung gas distribution in supratentorial craniotomy: a randomized controlled trial

BACKGROUND

Neurosurgical patients represent a high-risk population for postoperative pulmonary complications (PPCs). A lower intraoperative driving pressure (DP) is related to a reduction in postoperative pulmonary complications. We hypothesized that driving pressure-guided ventilation during supratentorial craniotomy might lead to a more homogeneous gas distribution in the lung postoperatively.

METHODS

This was a randomized trial conducted between June 2020 and July 2021 at Beijing Tiantan Hospital. Fifty-three patients undergoing supratentorial craniotomy were randomly divided into the titration group or control group at a ratio of 1 to 1. The control group received 5 cmH₂O PEEP, and the titration group received individualized PEEP targeting the lowest DP. The primary outcome was the global inhomogeneity index (GI) immediately after extubation obtained by electrical impedance tomography (EIT). The secondary outcomes were lung ultrasonography scores (LUSs), respiratory system compliance, the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO₂/FiO₂) and PPCs within 3 days postoperatively.

RESULTS

Fifty-one patients were included in the analysis. The median (IQR [range]) DP in the titration group versus the control group was 10 (9-12 [7-13]) cmH₂O vs. 11 (10-12 [7-13]) cmH₂O, respectively (P = 0.040). The GI tract did not differ between groups immediately after extubation (P = 0.080). The LUS_S was significantly lower in the titration group than in the control group immediately after tracheal extubation (1 [0-3] vs. 3 [1-6], P = 0.045). The compliance in the titration group was higher than that in the control group at 1 h after intubation (48 [42-54] vs. 41 [37-46] ml·cmH₂O^-1, P = 0.011) and at the end of surgery (46 [42-51] vs. 41 [37-44] ml·cmH₂O^-1, P = 0.029). The PaO₂/FiO₂ ratio was not significantly different between groups in terms of the ventilation protocol (P = 0.117). At the 3-day follow-up, no postoperative pulmonary complications occurred in either group.

CONCLUSIONS

Driving pressure-guided ventilation during supratentorial craniotomy did not contribute to postoperative homogeneous aeration, but it may lead to improved respiratory compliance and lower lung ultrasonography scores.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT04421976.

The association of intraoperative low driving pressure ventilation and nonhome discharge: a historical cohort study

PURPOSE

To evaluate whether intraoperative ventilation using lower driving pressure decreases the risk of nonhome discharge.

METHODS

We conducted a historical cohort study of patients aged ≥ 60 yr who were living at home before undergoing elective, noncardiothoracic surgery at two tertiary healthcare networks in Massachusetts between 2007 and 2018. We assessed the association of the median driving pressure during intraoperative mechanical ventilation with nonhome discharge using multivariable logistic regression analysis, adjusted for patient and procedural factors. Contingent on the primary association, we assessed effect modification by patients' baseline risk and mediation by postoperative respiratory failure.

RESULTS

Of 87,407 included patients, 12,584 (14.4%) experienced nonhome discharge. In adjusted analyses, a lower driving pressure was associated with a lower risk of nonhome discharge (adjusted odds ratio [aOR], 0.88; 95% confidence interval [CI], 0.83 to 0.93, per 10 cm H2O decrease; P < 0.001). This association was magnified in patients with a high baseline risk (aOR, 0.77; 95% CI, 0.73 to 0.81, per 10 cm H2O decrease, P-for-interaction < 0.001). The findings were confirmed in 19,518 patients matched for their baseline respiratory system compliance (aOR, 0.90; 95% CI, 0.81 to 1.00; P = 0.04 for low [< 15 cm H2O] vs high [≥ 15 cm H2O] driving pressures). A lower risk of respiratory failure mediated the association of a low driving pressure with nonhome discharge (20.8%; 95% CI, 15.0 to 56.8; P < 0.001).

CONCLUSIONS

Intraoperative ventilation maintaining lower driving pressure was associated with a lower risk of nonhome discharge, which can be partially explained by lowered rates of postoperative respiratory failure. Future randomized controlled trials should target driving pressure as a potential intervention to decrease nonhome discharge.

Association between driving pressure and postoperative pulmonary complications in patients undergoing lung resection surgery: A randomised clinical trial

BACKGROUND

It is uncertain whether an association exists for decreases in driving pressure and the occurrence of postoperative pulmonary complications (PPCs) in patients undergoing selective lung resection surgery. Thus, we designed this study to determine whether the positive end-expiratory pressure (PEEP) titration to the lowest driving pressure compared with conventional low PEEP level during one-lung ventilation (OLV) in patients undergoing selective lung resection surgery decreases PPCs.

METHODS

This single-centre, randomised trial approved by the Ethical Committee of the Sun Yat-Sen University Cancer Center involved patients who signed written consent. Patients were randomised to the PEEP titration to the lowest driving pressure group (n = 104), or to the conventional low level of PEEP group (n = 103), consisting a PEEP level of 4 cm H₂O during OLV. All patients received volume-controlled ventilation with a tidal volume of 6 mL/kg of predicted body weight. The primary outcome was defined as positive if 4 or more of eight Melbourne Group Scale (MGS) variables developed within the first 3 days after surgery. The incidence of major PPCs occurring during postoperative 7 days was also recorded.

RESULTS

Among 222 patients who were randomised, 207 (93%) completed the trial (109 men [53%]; mean age, 56.9 years). The primary outcome occurred in 4 of 104 patients (4%) in the PEEP titration to the lowest driving pressure group compared with 13 of 103 patients (13%) in the conventional low level of PEEP group (risk ratio, 0.32 [95% CI, 0.10-0.90]; P = 0.021).

CONCLUSIONS

Among patients undergoing selective lung surgery, intraoperative OLV with PEEP titration to the lowest driving pressure compared with conventional low PEEP level (4 cm H₂O) significantly reduced PPCs within the first 3 postoperative days, however, did not significantly reduce PPCs within the first 7 postoperative days.

The impact of inspiratory pressure level on prevention of ventilator-associated pneumonia: A double-blind, randomized clinical trial

BACKGROUND

Atelectasis and pneumonia are highly prevalent in patients under mechanical ventilation. Studies indicate that using ventilation with an open lung concept improves recovery, decreases ventilator-related pneumonia, decreases mortality and leads to faster weaning from the ventilator. Therefore, this study investigated the effect of higher airway pressure on ventilator-associated pneumonia.

METHODS

This randomized clinical trial was conducted on 120 patients under mechanical ventilation. The patients were divided into two groups based on ventilator pressure: the control group (pressure level 20) and the intervention group (pressure level 30). Demographic data, disease severity, the incidence of ventilator-associated pneumonia, organ damage, days connected to the ventilator, length of hospitalization in ICU, and mortality were compared between the two groups.

RESULTS

There was no significant difference in demographic data and disease severity between the two groups. The average Clinical Pulmonary Infection Score in the intervention group was significantly lower than the control group (P = 0.02). The intervention group's average Sequential Organ Failure Assessment score was significantly lower than the control group (p = 0.016).

CONCLUSIONS

High-pressure levels can decrease ventilator-associated pneumonia and organ failure. It is recommended that the study be repeated with a larger, more diverse population.

Individualized positive end-expiratory pressure guided by respiratory mechanics during anesthesia for the prevention of postoperative pulmonary complications: a systematic review and meta-analysis

The optimization of positive end-expiratory pressure (PEEP) according to respiratory mechanics [driving pressure or respiratory system compliance (Crs)] is a simple and straightforward strategy. However, its validity to prevent postoperative pulmonary complications (PPCs) remains unclear. Here, we performed a meta-analysis to assess such efficacy. We searched PubMed, Embase, and the Cochrane Library to identify randomized controlled trials (RCTs) that compared personalized PEEP based on respiratory mechanics and constant PEEP to prevent PPCs in adults. The primary outcome was PPCs. Fourteen studies with 1105 patients were included. Compared with those who received constant PEEP, patients who received optimized PEEP exhibited a significant reduction in the incidence of PPCs (RR = 0.54, 95% CI 0.42 to 0.69). The results of commonly happened PPCs (pulmonary infections, hypoxemia, and atelectasis but not pleural effusion) also supported individualized PEEP group. Moreover, the application of PEEP based on respiratory mechanics improved intraoperative respiratory mechanics (driving pressure and Crs) and oxygenation. The PEEP titration method based on respiratory mechanics seems to work positively for lung protection in surgical patients undergoing general anesthesia.