Intraoperative Mechanical Ventilation and Postoperative Pulmonary Complications after Cardiac Surgery

Intraoperative Factors Associated With Mechanical Ventilation Duration Following Aortic Surgery

OBJECTIVES

Prolonged postoperative mechanical ventilation is a common complication after major aortic surgery. The relationship between prolonged ventilation and intraoperative variables influenced by anesthesiologists, such as ventilation practices, fluid administration, and blood pressure control during major aortic surgery is unknown. We sought to identify perioperative factors, including intraoperative physiologic and anesthesia-related variables, which are associated with ventilation duration following aortic surgery.

DESIGN

Single-center retrospective observational study.

SETTING

A tertiary, high-volume cardiac surgery referral center.

PARTICIPANTS

Adult patients undergoing major aortic surgery requiring cardiopulmonary bypass (CPB).

INTERVENTIONS

None (retrospective observational study).

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the duration of postoperative ventilation (hours). Mixed-effects regression was performed to identify factors associated with the primary outcome. Among the 647 patients included in this study, the median of postoperative mechanical ventilation duration was 9.0 (IQR 6.0, 14.4) hours, with 73 (11.3%) of patients receiving mechanical ventilation for more than 24 hours. Variables significantly associated with the outcome were increases in pre- to post-CPB driving pressure (β = 4.23; 95% CI [0.08, 8.39]; p = 0.04), reduction in pre- to post-CPB end-tidal carbon dioxide partial pressure (β = -5.12; 95% CI [-8.85, -1.39]; p < 0.001), and normalized transfusion volumes (β = 11.14; 95% CI [4.36, 17.91]; p < 0.001). Mechanical power was not associated with postoperative ventilation duration (β = -2.29; 95% CI [-6.48, 1.90]; p = 0.52).

CONCLUSIONS

Patients undergoing major aortic surgery are at risk for prolonged mechanical ventilation. Transfusion volume and pre- to post-CPB changes in driving pressures and end-tidal carbon dioxide are significantly associated with postoperative ventilation duration. Intraoperative mechanical ventilator power is not a significant predictor of mechanical ventilation duration after major aortic surgery. These variables are potentially modifiable by anesthesiologists and may be future therapeutic targets.

Frequency and Predictors of Pneumonia After Isolated Coronary Artery Bypass Grafting (CABG): A Single-Center Study

Background: CABG is a commonly performed procedure to improve survival and quality of life in patients with coronary artery disease. Despite advances in surgical techniques and perioperative care, postoperative pneumonia remains a serious complication contributing to increased morbidity, mortality and healthcare costs. This study aims to evaluate the incidence of postoperative pneumonia (POP) and identify its risk factors in patients undergoing isolated CABG. Methods: This retrospective study analyzed 430 patients who underwent CABG between 2019 and 2024. Patient demographics, clinical characteristics, surgical details and laboratory data were collected. Statistical analysis included univariate and multivariate logistic regression to identify significant predictors of pneumonia. Results: The incidence of POP after CABG was 10% (43/430). In patients with POP, diabetes mellitus (p = 0.03) and chronic kidney disease (p = 0.048) prevalence was higher, cardiopulmonary bypass (CPB) (p = 0.01) and cross-clamp time (p = 0.003) was longer, LDH levels (p = 0.017) were higher, hemoglobin (p = 0.012) and albumin (p = 0.015) levels were lower, and lymphocyte % (p = 0.04) was lower; prevalence of COPD and length of stay (LOS) in hospital tended to be higher (both p < 0.06). Multivariate binary logistic regression identified COPD (OR 4.383, 95% CI: 1.106-17.363, p = 0.035), CPB time (OR 1.013, 95% CI: 1.001-1.025, p = 0.030) and LOS (OR 1.052, 95% CI: 1.004-1.103, p = 0.035) as independent predictors of POP. Conclusions: Postoperative pneumonia is a common complication after CABG and is strongly associated with preoperative COPD, CPB time and length of stay in hospital. These findings underline the importance of preoperative risk assessment and optimization. Early identification of high-risk patients may allow targeted strategies such as enhanced respiratory support and prophylactic antibiotics to reduce the incidence of pneumonia and improve clinical outcomes.

The predictive role of modified stress hyperglycemia rate in predicting early pneumonia after isolated coronary bypass surgery in patients with diabetes mellitus

Postoperative pneumonia (PP) is one of the most serious complications following coronary artery bypass graft (CABG) surgery. The recently developed admission blood glucose (ABG)/estimated average glucose (eAG) ratio has been identified as a prognostic marker in cardiovascular diseases. This study aimed to investigate the predictive role of the modified ABG/eAG (mABG/eAG) ratio in the development of pneumonia during the early postoperative period in diabetic patients undergoing CABG surgery. In this single-center study, diabetic patients who underwent isolated coronary bypass surgery at the Training and Research Hospital between 1 January 2018 and 1 January 2023 were included. Patients who did not develop PP were assigned to the control group, while those who developed PP were assigned to the PP group. A total of 549 patients were included in the study, 478 patients in the control group (median age = 58 years [range 35-81]) and 71 patients in the PP group (median age = 63 years [37-86]). In the multivariate analysis, the use of packed blood products (odds ratio [OR] = 1.685, 95% confidence interval [CI]: 1.453 - 1.892; P = 0.027), mABG/eAG ratio (OR = 1.659, 95% CI: 1.190 - 2.397; P = 0.019), and re-intubation (OR = 1.829, 95% CI: 1.656 - 1.945; P = 0.034) were identified as independent predictors for the development of PP. Our findings demonstrate that the mABG/eAG ratio is an independent predictor of PP in diabetic patients undergoing CABG surgery. Based on our results, high-risk patients can be identified by calculating the mABG/eAG ratio.

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.

A quality assurance protocol for reliable and reproducible multi-TI arterial spin labeling perfusion imaging in rat livers

OBJECTIVE

To establish an arterial spin labeling (ASL) protocol for rat livers that improves data reliability and reproducibility for perfusion quantification.

METHODS

This study used respiratory-gated, single-slice, FAIR-based ASL imaging with multiple inversion times (TI) in rat livers. Quality assurance measures included: (1) introduction of mechanical ventilation to ensure consistent respiratory cycles by controlling the respiratory rate (45 bpm), tidal volume (10 ml/kg), and inspiration: expiration ratio (I:E ratio, 1:2), (2) optimization of the trigger window for consistent trigger points, and (3) use of fit residual map and coefficient of variance as metrics to assess data quality. We compared image quality, perfusion maps, and fit residual maps between mechanically ventilated and non-ventilated animals, as well as repeated ASL measurements (session = 4 per animal) in two mechanically ventilated animals.

RESULTS

Perfusion measurements over multiple sessions in mechanically ventilated rats exhibited low perfusion data variability and high reproducibility both within and between liver lobes. Image quality and perfusion maps were significantly improved in mechanically ventilated animals compared to non-ventilated animals.

DISCUSSION

The implementation of mechanical ventilation and optimized quality assurance protocols enhanced the reliability and reproducibility of FAIR-based multi-TI-ASL imaging in rat livers. Our findings demonstrate these measures as a robust approach for achieving consistent liver perfusion quantification in preclinical settings.

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.

The Year in Cardiothoracic and Vascular Anesthesia: Selected Highlights from 2024

This special article is the 17th in an annual series for the Journal of Cardiothoracic and Vascular Anesthesia. The authors thank the editor in chief, Dr Kaplan, and the editorial board for the opportunity to continue this series, namely, the research highlights of the past year in the specialty of cardiothoracic and vascular anesthesiology.1 The major themes selected for 2024 are outlined in this introduction, and each highlight is reviewed in detail in the main article. The literature highlights in the specialty for 2024 begin with an update on perioperative rehabilitation and enhanced recovery in cardiothoracic surgery, with a focus on novel methods to best assess our patients in the preoperative period and the impact of implementing enhanced recovery care models on outcomes. The second major theme is focused on cardiac surgery, with the authors discussing new insights into anemia, transfusions, and coronary artery bypass grafting outcomes with a focus on gender disparities. The third theme is focused on cardiothoracic transplantation, with discussions focusing on techniques related to lung transplantation, including mechanical circulatory support. The 4th theme is focused on mechanical circulatory support, with discussions exploring advancements in left ventricular assist devices highlight the evolving landscape of mechanical circulatory support and discussion of anticoagulation practices. The fifth and final theme is an update on medical cardiology, with a focus on the outcomes of transcatheter management of regurgitant pathology, device management in heart failure, and new techniques in catheter ablation. The themes selected for this article are only a few of the diverse advances in the specialty during 2024. These highlights will inform the reader of key updates on a variety of topics, leading to improvement in perioperative outcomes for patients with cardiothoracic and vascular disease.

A Three-Day Prehabilitation Program is Cost-Effective for Preventing Pulmonary Complications after Heart Valve Surgery: A Health Economic Analysis of a Randomized Trial

Background

While prehabilitation (pre surgical exercise) effectively prevents postoperative pulmonary complications (PPCs), its cost-effectiveness in valve heart disease (VHD) remains unexplored. This study aims to evaluate the cost-effectiveness of a three-day prehabilitation program for reducing PPCs and improving quality adjusted life years (QALYs) in Chinese VHD patients.

Methods

A cost-effectiveness analysis was conducted alongside a randomized controlled trial featuring concealed allocation, blinded evaluators, and an intention-to-treat analysis. In total, 165 patients scheduled for elective heart valve surgery at West China Hospital were randomized into intervention and control groups. The intervention group participated in a three-day prehabilitation exercise program supervised by a physiotherapist while the control group received only standard preoperative education. Postoperative hospital costs were audited through the Hospital Information System, and the EuroQol five-dimensional questionnaire was used to provide a 12-month estimation of QALY. Cost and effect differences were calculated through the bootstrapping method, with results presented in cost-effectiveness planes, alongside the associated cost-effectiveness acceptability curve (CEAC). All costs were denominated in Chinese Yuan (CNY) at an average exchange rate of 6.73 CNY per US dollar in 2022.

Results

There were no statistically significant differences in postoperative hospital costs (8484 versus 9615 CNY, 95% CI -2403 to 140) or in the estimated QALYs (0.909 versus 0.898, 95% CI -0.013 to 0.034) between the intervention and control groups. However, costs for antibiotics (339 versus 667 CNY, 95% CI -605 to -51), nursing (1021 versus 1200 CNY, 95% CI -330 to -28), and electrocardiograph monitoring (685 versus 929 CNY, 95% CI -421 to -67) were significantly lower in the intervention group than in the control group. The CEAC indicated that the prehabilitation program has a 92.6% and 93% probability of being cost-effective in preventing PPCs and improving QALYs without incurring additional costs.

Conclusions

While the three-day prehabilitation program did not significantly improve health-related quality of life, it led to a reduction in postoperative hospital resource utilization. Furthermore, it showed a high probability of being cost-effective in both preventing PPCs and improving QALYs in Chinese patients undergoing valve surgery.

Clinical Registration Number

This trial is registered in the Chinese Clinical Trial Registry (URL: https://www.chictr.org.cn/) with the registration identifier ChiCTR2000039671.

Quality of life and functional capacity in patients after cardiac surgery intensive care unit

Coronary heart disease and aortic stenosis are prevalent cardiovascular diseases worldwide, leading to morbidity and mortality. Coronary artery bypass grafting (CABG) and surgical aortic valve replacement (SAVR) have therapeutic benefits, including improved postoperative quality of life (QoL) and enhanced patient functional capacity which are key indicators of cardiac surgery outcome. In this article, we review the latest studies of QoL outcomes and functional capacity in patients who underwent cardiac surgery. Many standardized instruments are used to evaluate QoL and functional conditions. Preoperative health status, age, length of intensive care unit stay, operative risk, type of procedure, and other pre-, intra-, and postoperative factors affect postoperative QoL. Elderly patients experience impaired physical status soon after cardiac surgery, but it improves in the following period. CABG and SAVR are associated with increases of physical and mental health and functional capacity in the immediate postoperative and the long long-term. Cardiac rehabilitation improves patient functional capacity, QoL, and frailty following cardiac surgery.

Identifying Early Risk Factors for Postoperative Pulmonary Complications in Cardiac Surgery Patients

Background and Objectives: Postoperative pulmonary complications (PPCs) are common in patients who undergo cardiac surgery and are widely acknowledged as significant contributors to increased morbidity, mortality rates, prolonged hospital stays, and healthcare costs. Clinical manifestations of PPCs can vary from mild to severe symptoms, with different radiological findings and varying incidence. Detecting early signs and identifying influencing factors of PPCs is essential to prevent patients from further complications. Our study aimed to determine the frequency, types, and risk factors significant for each PPC on the first postoperative day. The main goal of this study was to identify the incidence of pleural effusion (right-sided, left-sided, or bilateral), atelectasis, pulmonary edema, and pneumothorax as well as detect specific factors related to its development. Materials and Methods: This study was a retrospective single-center trial. It involved 314 adult patients scheduled for elective open-heart surgery under CPB. Results: Of the 314 patients reviewed, 42% developed PPCs within 12 h post-surgery. Up to 60.6% experienced one PPC, while 35.6% developed two PPCs. Pleural effusion was the most frequently observed complication in 89 patients. Left-sided effusion was the most common, presenting in 45 cases. Regression analysis showed a significant association between left-sided pleural effusion development and moderate hypoalbuminemia. Valve surgery was associated with reduced risk for left-sided effusion. Independent parameters for bilateral effusion include increased urine output and longer ICU stays. Higher BMI was inversely related to the risk of pulmonary edema. Conclusions: At least one PPC developed in almost half of the patients. Left-sided pleural effusion was the most common PPC, with hypoalbuminemia as a risk factor for effusion development. Atelectasis was the second most common. Bilateral effusion was the third most common PPC, significantly related to increased urine output. BMI was an independent risk factor for pulmonary edema development.

Variability and relative contribution of surgeon- and anesthesia-specific time components to total procedural time in cardiac surgery

BACKGROUND

Decreasing variability in time-intensive tasks during cardiac surgery may reduce total procedural time, lower costs, reduce clinician burnout, and improve patient access. The relative contribution and variability of surgeon control time (SCT) and anesthesia control time (ACT) to total procedural time is unknown.

METHODS

A total of 669 patients undergoing coronary artery bypass graft (CABG) surgery were enrolled. Using linear regression, we estimated adjusted SCTs and ACTs, controlling for patient and procedural covariates. The primary endpoint compared overall SCTs and ACTs. The secondary endpoint compared the variability in adjusted SCTs and ACTs. Sensitivity analyses quantified the relative importance of the specific surgeon and anesthesiologist in the adjusted linear models.

RESULTS

The median SCT was 4.1 hours (interquartile range [IQR], 3.4-4.9 hours) compared to a median ACT of 1.0 hours (IQR, 0.8-1.2 hours; P < .001). Using linear regression, the variability in adjusted SCT among surgeons (range, 1.8 hours) was 3.5-fold greater than the variability in adjusted ACT among anesthesiologists (range, 0.5 hour; P < .001). The specific surgeon and anesthesiologist accounted for 50% of the explanatory power of the predictive model (P < .001).

CONCLUSIONS

SCT variability is significantly greater than ACT variability and is strongly associated with the surgeon performing the procedure. Although these results suggest that SCT variability is an attractive operational target, further studies are needed to determine practitioner specific and modifiable attributes to reduce variability and improve efficiency.

Predictive value of gradient boosting decision trees for postoperative atelectasis complications in patients with pulmonary destruction

OBJECTIVE

To explore the application value of a gradient boosting decision tree (GBDT) in predicting postoperative atelectasis in patients with destroyed lungs.

METHODS

A total of 170 patients with damaged lungs who underwent surgical treatment in Chest Hospital of Guangxi Zhuang Autonomous Region from January 2021 to May 2023 were retrospectively selected. The patients were divided into a training set (n = 119) and a validation set (n = 51). Both GBDT algorithm model and Logistic regression model for predicting postoperative atelectasis in patients were constructed. The receiver operating characteristic (ROC) curve, calibration curve and decision curve were used to evaluate the prediction efficiency of the model.

RESULTS

The GBDT model indicated that the relative importance scores of the four influencing factors were operation time (51.037), intraoperative blood loss (38.657), presence of lung function (9.126) and sputum obstruction (1.180). Multivariate Logistic regression analysis revealed that operation duration and sputum obstruction were significant predictors of postoperative atelectasis among patients with destroyed lungs within the training set (P = 0.048, P = 0.002). The ROC curve analysis showed that the area under the curve (AUC) for GBDT and Logistic model in the training set was 0.795 and 0.763, and their AUCs in the validation set were 0.776 and 0.811. The GBDT model's predictions closely matched the ideal curve, showing a higher net benefit than the reference line.

CONCLUSIONS

GBDT model is suitable for predicting the incidence of complications in small samples.

Electrical Impedance Tomography-based Ventilation Patterns in Patients after Major Surgery

Rationale: General anesthesia and mechanical ventilation have negative impacts on the respiratory system, causing heterogeneous distribution of lung aeration, but little is known about the ventilation patterns of postoperative patients and their association with clinical outcomes. Objectives: To clarify the phenotypes of ventilation patterns along a gravitational direction after surgery by using electrical impedance tomography (EIT) and to evaluate their association with postoperative pulmonary complications (PPCs) and other relevant clinical outcomes. Methods: Adult postoperative patients at high risk for PPCs, receiving mechanical ventilation on ICU admission (N = 128), were prospectively enrolled between November 18, 2021 and July 18, 2022. PPCs were prospectively scored until hospital discharge, and their association with phenotypes of ventilation patterns was studied. The secondary outcomes were the times to wean from mechanical ventilation and oxygen use and the length of ICU stay. Measurements and Main Results: Three phenotypes of ventilation patterns were revealed by EIT: phenotype 1 (32% [n = 41], a predominance of ventral ventilation), phenotype 2 (41% [n = 52], homogeneous ventilation), and phenotype 3 (27% [n = 35], a predominance of dorsal ventilation). The median PPC score was higher in phenotype 1 and phenotype 3 than in phenotype 2. The median time to wean from mechanical ventilation was longer in phenotype 1 versus phenotype 2. The median duration of ICU stay was longer in phenotype 1 versus phenotype 2. The median time to wean from oxygen use was longer in phenotype 1 and phenotype 3 than in phenotype 2. Conclusions: Inhomogeneous ventilation patterns revealed by EIT on ICU admission were associated with PPCs, delayed weaning from mechanical ventilation and oxygen use, and a longer ICU stay.

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

The impact of prolonged mechanical ventilation after acute type A aortic dissection repair

OBJECTIVE

Patients with type A aortic dissection have increased resource use. The objective of this study was to describe the relationship between prolonged mechanical ventilation and longitudinal survival in patients undergoing type A aortic dissection repair.

METHODS

We conducted a retrospective analysis of patients with type A aortic dissection undergoing repair from 2010 to 2018; Kaplan-Meier function and adjusted Cox regression analysis were used to compare in-hospital mortality and longitudinal survival accounting for time on mechanical ventilatory support.

RESULTS

A total of 552 patients were included. The study population was divided into 12 hours or less (n = 291), more than 12 to 24 or less hours (n = 101), more than 24 to 48 hours or less (n = 60), and more than 48 hours (n = 100) groups. Patients within the 12 or less hours group were the youngest (60.0 vs 63.5 years vs 63.6 vs 62.8 years; P = .03) and less likely to be female (31.6% vs 43.6% vs 46.7% vs 56.0%; P < .001). On the other hand, the more than 48 hours group presented with malperfusion syndrome at admission more often (24.4% vs 29.7% vs 28.3% vs 53.0%; P < .001) and had longer cardiopulmonary and ischemic times (P < .05). In-hospital mortality was significantly higher in the more than 48 hours group (5.2% vs 6.9% vs 3.3% vs 30.0%; P < .001). Multivariable analysis demonstrated worse longitudinal survival for the 24 to 48 hours group (hazard ratio, 1.94, confidence interval, 1.10-3.43) and more than 48 hours ventilation group (hazard ratio, 2.25, confidence interval, 1.30-3.92).

CONCLUSIONS

The need for prolonged mechanical ventilatory support is prevalent and associated with other perioperative complications. More important, after adjusting for other covariates, prolonged mechanical ventilation is an independent factor associated with increased longitudinal mortality.

The predictive and prognostic value of risk factors in patients receiving hybrid coronary revascularization with postoperative pulmonary complications

Background

The mortality rate of coronary artery disease ranks first in developed countries, and coronary revascularization therapy is an important cornerstone of its treatment. The postoperative pulmonary complications (PPCs) in patients receiving one-stop hybrid coronary revascularization (HCR) aggravate the dysfunction of multiple organs such as the heart and lungs, therefore increasing mortality. However, the risk factors are still unclear. The objective of this study was to explore the risk factors of PPCs after HCR surgery.

Methods

In this study, the perioperative data of 311 patients undergoing HCR surgery were reviewed. All patients were divided into two groups according to whether the PPCs occurred. The baseline information and surgery-related indicators in preoperative laboratory examination, intraoperative fluid management, and anesthesia management were compared between the two groups.

Results

Advanced age [odds ratio (OR): 1.065, 95% confidence interval (CI): 1.030-1.101, P<0.001], high body mass index (BMI; OR: 1.113, 95% CI: 1.011-1.225, P=0.02), history of percutaneous coronary intervention (PCI) surgery (OR: 2.831, 95% CI: 1.388-5.775, P=0.004), one-lung volume ventilation (OR: 3.804, 95% CI: 1.923-7.526, P<0.001), inhalation of high concentration oxygen (OR: 3.666, 95% CI: 1.719-7.815, P=0.001), the application of positive end-expiratory pressure (PEEP; OR: 2.567, 95% CI: 1.338-4.926, P=0.005), and long one-lung ventilation time (OR: 1.015, 95% CI: 1.006-1.023, P=0.001) may be risk factors for postoperative PPCs in patients undergoing one-stop coronary revascularization surgery. Using the above seven factors to jointly predict the risk of PPCs in patients undergoing one-stop coronary revascularization surgery, the receiver operating characteristic (ROC) curve showed an area under the curve (AUC) =0.873, 95% CI: 0.835-0.911, sensitivity: 84.81%, and specificity: 75.82%; the predictive model was shown to be effective.

Conclusions

Patients undergoing HCR surgery with advanced age, high BMI, a history of PCI surgery, one-lung volume ventilation, inhalation of high concentration oxygen, use of PEEP, and prolonged single lung ventilation are more prone to PPCs.

Association of Sarcopenia, as Defined Based on the Skeletal Muscle Index, With Mortality and Morbidity After Cardiac Surgery: A Retrospective Cohort Study

OBJECTIVE

To investigate whether "sarcopenia," defined based on the preoperative skeletal muscle index (SMI), can predict major postoperative morbidity and all-cause mortality.

DESIGN

A retrospective observational cohort study.

SETTING

At the authors' Department of Critical Care Medicine.

PARTICIPANTS

A total of 986 adult Chinese patients underwent cardiac surgery (coronary artery bypass graft, valve surgery, combined surgery, or aortic surgery) between January 2019 and August 2022.

MEASUREMENTS AND MAIN RESULTS

The skeletal muscle area at the third lumbar level (L3) was measured via preoperative computed tomography (up to 3 months from the date of imaging to the date of surgery) and normalized to patient height (skeletal muscle index). Sarcopenia was determined based on the skeletal muscle index being in the lowest sex-specific quartile. The primary outcome was all-cause mortality. The secondary outcome was major morbidity. A total of 968 patients were followed for a median of 2.00 years, ranging from 1.06 to 2.90 years. After the follow-up, 76 patients died during the follow-up period. Multivariate Cox proportional analysis showed a relationship between sarcopenia (adjusted hazard ratio 1.80, 95% CI 1.04-3.11; p = 0.034) and all-cause mortality. Kaplan-Meier curves revealed a significantly lower survival rate in the sarcopenia group than in the nonsarcopenia group. Overall, 199 (20.6%) patients had major morbidity. Multivariate analysis showed a significant relationship between sarcopenia (adjusted odds ratio = 2.21, 95% CI 1.52∼3.22, p < 0.001) and major morbidity.

CONCLUSIONS

Sarcopenia, defined by the skeletal muscle index, is associated with all-cause mortality and major morbidity after cardiac surgery, thereby suggesting the need for perioperative sarcopenia risk assessment for patients undergoing cardiac surgery to guide the prevention and management of adverse outcomes.

A Predictive Model for Prolonged Mechanical Ventilation After Triple-Branched Stent Graft for Acute Type A Aortic Dissection

INTRODUCTION

The aim of this study is to develop a model for predicting the risk of prolonged mechanical ventilation (PMV) following surgical repair of acute type A aortic dissection (AAAD).

METHODS

We retrospectively collected clinical data from 381 patients with AAAD who underwent emergency surgery. Clinical features variables for predicting postoperative PMV were selected through univariate analysis, least absolute shrinkage and selection operator regression analysis, and multivariate logistic regression analysis. A risk prediction model was established using a nomogram. The model's accuracy and reliability were evaluated using the area under the curve of the receiver operating characteristic curve and the calibration curve. Internal validation of the model was performed using bootstrap resampling. The clinical applicability of the model was assessed using decision curve analysis and clinical impact curve.

RESULTS

Among the 381 patients, 199 patients (52.2%) experienced postoperative PMV. The predictive model exhibited good discriminative ability (area under the curve = 0.827, 95% confidence interval: 0.786-0.868, P < 0.05). The calibration curve confirmed that the predicted outcomes of the model closely approximated the ideal curve, indicating agreement between the predicted and actual results (with an average absolute error of 0.01 based on 1000 bootstrap resampling). The decision curve analysis curve demonstrated that the model has significant clinical value.

CONCLUSIONS

The nomogram model established in this study can be used to predict the risk of postoperative PMV in patients with AAAD. It serves as a practical tool to assist clinicians in adjusting treatment strategies promptly and implementing targeted therapeutic measures.

Perioperative Care in Cardiac Surgery: A Joint Consensus Statement by the Enhanced Recovery After Surgery (ERAS) Cardiac Society, ERAS International Society, and The Society of Thoracic Surgeons (STS)

Enhanced Recovery After Surgery (ERAS) programs have been shown to lessen surgical insult, promote recovery, and improve postoperative clinical outcomes across a number of specialty operations. A core tenet of ERAS involves the provision of protocolized evidence-based perioperative interventions. Given both the growing enthusiasm for applying ERAS principles to cardiac surgery and the broad scope of relevant interventions, an international, multidisciplinary expert panel was assembled to derive a list of potential program elements, review the literature, and provide a statement regarding clinical practice for each topic area. This article summarizes those consensus statements and their accompanying evidence. These results provide the foundation for best practice for the management of the adult patient undergoing cardiac surgery.

Effects of Intra-operative Cardiopulmonary Variability On Post-operative Pulmonary Complications in Major Non-cardiac Surgery: A Retrospective Cohort Study

Intraoperative cardiopulmonary variables are well-known predictors of postoperative pulmonary complications (PPC), traditionally quantified by median values over the duration of surgery. However, it is unknown whether cardiopulmonary instability, or wider intra-operative variability of the same metrics, is distinctly associated with PPC risk and severity. We leveraged a retrospective cohort of adults (n = 1202) undergoing major non-cardiothoracic surgery. We used multivariable logistic regression to evaluate the association of two outcomes (1)moderate-or-severe PPC and (2)any PPC with two sets of exposure variables- (a)variability of cardiopulmonary metrics (inter-quartile range, IQR) and (b)median intraoperative cardiopulmonary metrics. We compared predictive ability (receiver operating curve analysis, ROC) and parsimony (information criteria) of three models evaluating different aspects of the intra-operative cardiopulmonary metrics: Median-based: Median cardiopulmonary metrics alone, Variability-based: IQR of cardiopulmonary metrics alone, and Combined: Medians and IQR. Models controlled for peri-operative/surgical factors, demographics, and comorbidities. PPC occurred in 400(33%) of patients, and 91(8%) experienced moderate-or-severe PPC. Variability in multiple intra-operative cardiopulmonary metrics was independently associated with risk of moderate-or-severe, but not any, PPC. For moderate-or-severe PPC, the best-fit predictive model was the Variability-based model by both information criteria and ROC analysis (area under the curve, AUCVariability-based = 0.74 vs AUCMedian-based = 0.65, p = 0.0015; AUCVariability-based = 0.74 vs AUCCombined = 0.68, p = 0.012). For any PPC, the Median-based model yielded the best fit by information criteria. Predictive accuracy was marginally but not significantly higher for the Combined model (AUCCombined = 0.661) than for the Median-based (AUCMedian-based = 0.657, p = 0.60) or Variability-based (AUCVariability-based = 0.649, p = 0.29) models. Variability of cardiopulmonary metrics, distinct from median intra-operative values, is an important predictor of moderate-or-severe PPC.

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.

Risk factors and early outcomes of prolonged mechanical ventilation following redo aortic arch surgery: A retrospective study

BACKGROUND

Redo aortic arch surgery is complex and associated with higher risks and mortality. Prolonged mechanical ventilation (PMV) after cardiac surgery is linked to early adverse outcomes and increased costs.

OBJECTIVES

Identify specific risk factors and early complications associated with PMV following redo aortic arch surgery.

METHODS

Retrospective study at Fuwai Hospital involving 203 patients. Data on patient characteristics, intraoperative factors, and outcomes were analyzed.

RESULTS

A total of 203 patients were included, with 42.4 % requiring PMV. PMV patients had longer ICU stays (P < 0.001), lower discharge ADL scores (P < 0.001), and higher hospitalization costs (P < 0.001). While there was no significant difference in-hospital mortality between the two groups, the long-term survival rate in the PMV group was lower than that in the non-PMV group (P = 0.029). Multivariate analysis identified longer cardiopulmonary bypass time (OR 1.008, 95% CI, 1.002 - 1.014, P = 0.006), elevated intraoperative red blood cell transfusion(OR 1.214, 95% CI, 1.057 - 1.393, P = 0.006), higher PEEP (OR 1.296, 95% CI 1.089 - 1.542, P = 0.003), and total arch replacement (OR 3.241, 95% CI 1.392 - 7.543, P = 0.006) as independent risk factors for PMV.

CONCLUSION

PMV following redo aortic arch surgery is linked to early adverse outcomes, increased healthcare costs, and reduced long-term survival, with longer cardiopulmonary bypass times, elevated intraoperative red blood cell transfusion, higher PEEP, and total arch replacement as independent risk factors.

Identifying High-Risk Patients for Severe Pulmonary Complications after Cardiosurgical Procedures as a Target Group for Further Assessment of Lung-Protective Strategies

OBJECTIVES

It remains unclear whether intraoperative lung-protective strategies can reduce the rate of respiratory complications after cardiac surgery, partly because low-risk patients have been studied in the past. The authors established a screening model to easily identify a high-risk group for severe pulmonary complications (ie, pneumonia or acute respiratory distress syndrome) that may be the ideal target population for the assessment of the potential benefits of such measures.

DESIGN

Retrospective observational trial.

SETTING

Departments of cardiac surgery and cardiac anesthesia of a university hospital.

PARTICIPANTS

Consecutive patients undergoing cardiac surgery on cardiopulmonary bypass and subsequent treatment at a dedicated cardiosurgical intensive care unit between January 2019 and March 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of the 2,572 patients undergoing surgery, 84 (3.3%) developed pneumonia/acute respiratory distress syndrome that significantly affected the outcome (ie, longer ventilatory support [66% vs 11%], higher reintubation rate [39% vs 3%]), prolonged length of intensive care unit [33 ± 36 vs 4 ± 10 days] and hospital stay [10 ± 15 vs 6 ± 7 days], and higher in-hospital [43% vs 9%] as well as 30-day [7% vs 3%] mortality). The screening model for severe pulmonary complications included left ventricular ejection fraction <52%, EuroSCORE II (European System for Cardiac Operative Risk Evaluation II) >5.9, cardiopulmonary bypass time >123 minutes, left ventricular assist device or aortic repair surgery, and bronchodilatory therapy. A cutoff for the predicted risk of 2.5% showed optimal sensitivity and specificity, with an area under the receiver operating characteristic curve of 0.82.

CONCLUSIONS

The authors suggest that future research on intraoperative lung-protective measures focuses on this high-risk population, primarily aiming to mitigate severe forms of postoperative pulmonary dysfunction associated with poor outcomes and increased resource consumption.

Effect of Mechanical Ventilation Mode Type on Postoperative Pulmonary Complications After Cardiac Surgery: A Randomized Controlled Trial

OBJECTIVES

It is unknown whether there is a difference in pulmonary outcome in different intraoperative ventilation modes for cardiac surgery with cardiopulmonary bypass (CPB). The aim of this trial was to determine whether patients undergoing cardiac surgery with CPB could benefit from intraoperative optimal ventilation mode.

DESIGN

This was a single-center, prospective, randomized controlled trial.

SETTING

The study was conducted at a single-center tertiary-care hospital.

PARTICIPANTS

A total of 1,364 adults undergoing cardiac surgery with CPB participated in this trial.

INTERVENTIONS

Patients were assigned randomly (1:1:1) to receive 1 of 3 ventilation modes: volume-controlled ventilation (VCV), pressure-controlled ventilation (PCV), and pressure-controlled ventilation-volume guaranteed (PCV-VG). All arms of the study received the lung-protective ventilation strategy.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was a composite of postoperative pulmonary complications (PPCs) within the first 7 postoperative days. Pulmonary complications occurred in 168 of 455 patients (36.9%) in the PCV-VG group, 171 (37.6%) in the PCV group, and 182 (40.1%) in the VCV group, respectively. There was no statistical difference in the risk of overall pulmonary complications among groups (p = 0.585). There were no significant differences in the severity grade of PPCs within 7 days, postoperative ventilation duration, intensive care unit stay, postoperative hospital stay, or 30-day postoperative mortality.

CONCLUSIONS

Among patients scheduled for cardiac surgery with CPB, intraoperative ventilation mode type did not affect the risk of postoperative pulmonary complications.

Risk Factors and Short-Term Outcomes of Postoperative Pulmonary Complications in Elderly Patients After Cardiopulmonary Bypass

Objective

The risk factors of postoperative pulmonary complications (PPCs) have been extensively investigated in non-cardiac surgery and non-elderly adult patients undergoing cardiac surgery. However, data on elderly patients after cardiopulmonary bypass (CPB) is limited. This study aimed to evaluate the risk factors and short-term outcomes for PPCs in elderly patients undergoing CPB procedures.

Patients and Methods

Data from 660 patients who underwent CPB over a six-year period at a tertiary care hospital were collected. The primary outcome encompassed the incidence of PPCs, including re-intubation, postoperative mechanical ventilation exceeding 48 hours, pulmonary infection, pleural effusion requiring thoracic drainage, and acute respiratory distress syndrome. Missing data were managed using multiple imputation. Univariate analysis and the multiple logistic regression method were utilized to ascertain independent risk factors for PPCs.

Results

Among the 660 patients, PPCs were observed in 375 individuals (56.82%). Multiple logistic regression identified serum albumin levels <40 g/L, type of surgery, CPB duration >150 minutes, blood transfusion, and intra-aortic balloon pump use before extubation as independent risk factors for PPCs. Patients experiencing PPCs had prolonged mechanical ventilation, extended hospitalization and ICU stays, elevated postoperative mortality, and higher tracheotomy rates compared to those without PPCs.

Conclusion

Elderly patients following CPB displayed a substantially high incidence of PPCs, significantly impacting their prognosis. Additionally, this study identified five prominent risk factors associated with PPCs in this population. These findings enable clinicians to better recognize patients who may benefit from perioperative prevention strategies based on these risk factors.

Flow-controlled versus pressure-controlled ventilation in cardiac surgery with cardiopulmonary bypass - A single-center, prospective, randomized, controlled trial

STUDY OBJECTIVE

Multifactorial comparison of flow-controlled ventilation (FCV) to standard of pressure-controlled ventilation (PCV) in terms of oxygenation in cardiac surgery patients after chest closure.

DESIGN

Prospective, non-blinded, randomized, controlled trial.

SETTING

Operating theatre at an university hospital, Austria.

PATIENTS

Patients scheduled for elective, open, on-pump, cardiac surgery.

INTERVENTIONS

Participants were randomized to either individualized FCV (compliance guided end-expiratory and peak pressure setting) or control of PCV (compliance guided end-expiratory pressure setting and tidal volume of 6-8 ml/kg) for the duration of surgery.

MEASUREMENTS

The primary outcome measure was oxygenation (PaO2/FiO2) 15 min after intraoperative chest closure. Secondary endpoints included CO2-removal assessed as required minute volume to achieve normocapnia and lung tissue aeration assessed by Hounsfield unit distribution in postoperative computed tomography scans.

MAIN RESULTS

Between April 2020 and April 2021 56 patients were enrolled and 50 included in the primary analysis (mean age 70 years, 38 (76%) men). Oxygenation, assessed by PaO2/FiO2, was significantly higher in the FCV group (n = 24) compared to the control group (PCV, n = 26) (356 vs. 309, median difference (MD) 46 (95% CI 3 to 90) mmHg; p = 0.038). Additionally, the minute volume required to obtain normocapnia was significantly lower in the FCV group (4.0 vs. 6.1, MD -2.0 (95% CI -2.5 to -1.5) l/min; p < 0.001) and correlated with a significantly lower exposure to mechanical power (5.1 vs. 9.8, MD -5.1 (95% CI -6.2 to -4.0) J/min; p < 0.001). Evaluation of lung tissue aeration revealed a significantly reduced amount of non-aerated lung tissue in FCV compared to PCV (5 vs. 7, MD -3 (95% CI -4 to -1) %; p < 0.001).

CONCLUSIONS

In patients undergoing on-pump, cardiac surgery individualized FCV significantly improved oxygenation and lung tissue aeration compared to PCV. In addition, carbon dioxide removal was accomplished at a lower minute volume leading to reduced applied mechanical power.

Perioperative Management in Pulmonary Endarterectomy

Pulmonary endarterectomy (PEA) is the treatment of choice for patients with chronic thromboembolic pulmonary hypertension (PH), provided lesions are proximal enough in the pulmonary vasculature to be surgically accessible and the patient is well enough to benefit from the operation in the longer term. It is a major cardiothoracic operation, requiring specialized techniques and instruments developed over several decades to access and dissect out the intra-arterial fibrotic material. While in-hospital operative mortality is low (<5%), particularly in high-volume centers, careful perioperative management in the operating theater and intensive care is mandatory to balance ventricular performance, fluid balance, ventilation, and coagulation to avoid or treat complications. Reperfusion pulmonary edema, airway hemorrhage, and right ventricular failure are the most problematic complications, often requiring the use of extracorporeal membrane oxygenation to bridge to recovery. Successful PEA has been shown to improve both morbidity and mortality in large registries, with survival >70% at 10 years. For patients not suitable for PEA or with residual PH after PEA, balloon pulmonary angioplasty and/or PH medical therapy may prove beneficial. Here, we describe the indications for PEA, specific surgical and perioperative strategies, postoperative monitoring and management, and approaches for managing residual PH in the long term.

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.

Individualised positive end-expiratory pressure titrated intra-operatively by electrical impedance tomography optimises pulmonary mechanics and reduces postoperative atelectasis: A randomised controlled trial

BACKGROUND

A protective intra-operative lung ventilation strategy has been widely recommended for laparoscopic surgery. However, there is no consensus regarding the optimal level of positive end-expiratory pressure (PEEP) and its effects during pneumoperitoneum. Electrical impedance tomography (EIT) has recently been introduced as a bedside tool to monitor lung ventilation in real-time.

OBJECTIVE

We hypothesised that individually titrated EIT-PEEP adjusted to the surgical intervention would improve respiratory mechanics during and after surgery.

DESIGN

Randomised controlled trial.

SETTING

First Medical Centre of Chinese PLA General Hospital, Beijing.

PATIENTS

Seventy-five patients undergoing robotic-assisted laparoscopic hepatobiliary and pancreatic surgery under general anaesthesia.

INTERVENTIONS

Patients were randomly assigned 2 : 1 to individualised EIT-titrated PEEP (PEEPEIT; n = 50) or traditional PEEP 5 cmH2O (PEEP5 cmH2O; n = 25). The PEEPEIT group received individually titrated EIT-PEEP during pneumoperitoneum. The PEEP5 cmH2O group received PEEP of 5 cmH2O during pneumoperitoneum.

MAIN OUTCOME MEASURES

The primary outcome was respiratory system compliance during laparoscopic surgery. Secondary outcomes were individualised PEEP levels, oxygenation, respiratory and haemodynamic status, and occurrence of postoperative pulmonary complications (PPCs) within 7 days.

RESULTS

Compared with PEEP5 cmH2O, patients who received PEEPEIT had higher respiratory system compliance (mean values during surgery of 44.3 ± 11.3 vs. 31.9 ± 6.6, ml cmH2O-1; P < 0.001), lower driving pressure (11.5 ± 2.1 vs. 14.0 ± 2.4 cmH2O; P < 0.001), better oxygenation (mean PaO2/FiO2 427.5 ± 28.6 vs. 366.8 ± 36.4; P = 0.003), and less postoperative atelectasis (19.4 ± 1.6 vs. 46.3 ± 14.8 g of lung tissue mass; P = 0.003). Haemodynamic values did not differ significantly between the groups. No adverse effects were observed during surgery.

CONCLUSION

Individualised PEEP by EIT may improve intra-operative pulmonary mechanics and oxygenation without impairing haemodynamic stability, and decrease postoperative atelectasis.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (www.chictr.org.cn) identifier: ChiCTR2100045166.

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).

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.

Impact of Pulmonary Complications on Outcomes and Resource Use After Elective Cardiac Surgery

OBJECTIVE

To characterize the impact of pulmonary complications (PCs) on mortality, costs, and readmissions after elective cardiac operations in a national cohort and to test for hospital-level variation in PC.

BACKGROUND

PC after cardiac surgery are targets for quality improvement efforts. Contemporary studies evaluating the impact of PC on outcomes are lacking, as is data regarding hospital-level variation in the incidence of PC.

METHODS

Adults undergoing elective coronary artery bypass grafting and/or valve operations were identified in the 2016-2019 Nationwide Readmissions Database. PC was defined as a composite of reintubation, prolonged (>24 hours) ventilation, tracheostomy, or pneumonia. Generalized linear models were fit to evaluate associations between PC and outcomes. Institutional variation in PC was studied using observed-to-expected ratios.

RESULTS

Of 588,480 patients meeting study criteria, 6.7% developed PC. After risk adjustment, PC was associated with increased odds of mortality (14.6, 95% CI, 12.6-14.8), as well as a 7.9-day (95% CI, 7.6-8.2) increase in length of stay and $41,300 (95% CI, 39,600-42,900) in attributable costs. PC was associated with 1.3-fold greater hazard of readmission and greater incident mortality at readmission (6.7% vs 1.9%, P <0.001). Significant hospital-level variation in PC was present, with observed-to-expected ratios ranging from 0.1 to 7.7.

CONCLUSIONS

Pulmonary complications remain common after cardiac surgery and are associated with substantially increased mortality and expenditures. Significant hospital-level variation in PC exists in the United States, suggesting the need for systematic quality improvement efforts to reduce PC and their impact on outcomes.

Clinical Predictors and Outcomes After Left Ventricular Assist Device Implantation and Tracheostomy

BACKGROUND

Postoperative respiratory failure is a major complication that affects up to 10% of patients who undergo cardiac surgery and has a high in-hospital mortality rate. Few studies have investigated whether patients who require tracheostomy for postoperative respiratory failure after continuous-flow left ventricular assist device (CF-LVAD) implantation have worse survival outcomes than patients who do not.

OBJECTIVE

To identify risk factors for respiratory failure necessitating tracheostomy in CF-LVAD recipients and to compare survival outcomes between those who did and did not require tracheostomy.

METHODS

Consecutive patients who underwent primary CF-LVAD placement at a single institution between August 1, 2002, and December 31, 2019, were retrospectively reviewed. Propensity score matching accounted for baseline differences between the tracheostomy and nontracheostomy groups. Multivariate logistic regression was used to identify tracheostomy risk factors and 90-day survival; Kaplan-Meier analysis was used to assess midterm survival.

RESULTS

During the study period, 664 patients received a CF-LVAD; 106 (16.0%) underwent tracheostomy for respiratory failure. Propensity score matching produced 103 matched tracheostomy-nontracheostomy pairs. Patients who underwent tracheostomy were older (mean [SD] age, 57.9 [12.3] vs 54.6 [13.9] years; P = .02) and more likely to need preoperative mechanical circulatory support (61.3% vs 47.8%; P = .01) and preoperative intubation (27.4% vs 8.8%; P < .001); serum creatinine was higher in the tracheostomy group (mean [SD], 1.7 [1.0] vs 1.4 [0.6] mg/dL; P < .001), correlating with tracheostomy need (odds ratio, 1.76; 95% CI, 1.21-2.56; P = .003). Both before and after propensity matching, 30-day, 60-day, 90-day, and 1-year survival were worse in patients who underwent tracheostomy. Median follow-up was 0.8 years (range, 0.0-11.2 years). Three-year Kaplan-Meier survival was significantly worse for the tracheostomy group before (22.0% vs 61.0%; P < .001) and after (22.4% vs 48.3%; P < .001) matching.

CONCLUSION

Given the substantially increased probability of death in patients who develop respiratory failure and need tracheostomy, those at high risk for respiratory failure should be carefully considered for CF-LVAD implantation. Comprehensive management to decrease respiratory failure before and after surgery is critical.

Fibrotic extracellular vesicles contribute to mechanical ventilation-induced pulmonary fibrosis development by activating lung fibroblasts via JNK signalling pathway: an experimental study

Recent research has revealed that mechanical ventilation (MV) could initiate ventilator-induced lung injury along with the initiation of the process of pulmonary fibrosis (PF), leading to MV-induced PF (MVPF). However, the underlying mechanism remains unclear. This study aimed to explore the role of MV-induced extracellular vesicles (MV-EVs) and the c-Jun N-terminal kinase (JNK) signalling pathway in the pathogenesis of MVPF in vivo and in vitro. The process of MV is accompanied by the secretion of MV-EVs, which could induce lung fibroblast activation. Furthermore, single-cell RNA-sequencing analysis revealed that the JNK pathway in lung fibroblasts was activated after MV initiation. Inhibiting the JNK pathway could both restrain MV-EV-induced lung fibroblast activation in vitro or reduce the severity of MVPF in vivo. In conclusion, this study demonstrated that MV-EVs contribute to MVPF progression by activating lung fibroblasts via the JNK signalling pathway and that inhibiting the secretion of EV and the activation of the JNK signalling pathway is a promising strategy for treating MVPF.

[Risk factors for postoperative hypoxemia during transport to the postanesthesia care unit and influence of transport monitoring : A retrospective propensity score-matched databank analysis]

BACKGROUND

Within a central operating room area, after general anesthesia (GA) patients are at risk of hypoxemia during transport to the postanesthesia care unit (PACU); however, specific risk factors have not been conclusively clarified and uniform recommendations for monitoring vital signs during transport within a central operating room area complex do not exist. The purpose of this retrospective database analysis was to identify risk factors for hypoxemia during this transport and to determine whether the use of transport monitoring (TM) affects the initial value of peripheral venous oxygen saturation (S_pO₂) in the PACU.

MATERIAL AND METHODS

This analysis was performed on a retrospectively extracted dataset of procedures in GA within a central operating room area of a tertiary care hospital from 2015 to 2020. The emergence from GA was conducted in the operating room with subsequent transport to the PACU. The transport distance was between 31 and 72 m. Risk factors for initial hypoxemia in the PACU, defined as peripheral oxygen saturation (S_pO₂) below 90%, were determined using multivariate analysis. After splitting the dataset into patients without TM (group OM) and with TM (group MM) and propensity score matching, the influence of TM on initial S_pO₂ and the Aldrete score after arrival in the PACU were examined.

RESULTS AND DISCUSSION

From a total of 22,638 complete datasets included in the analysis, 8 risk factors for initial hypoxemia in PACU were identified: age > 65 years, body mass index (BMI) > 30 kg/m², chronic obstructive pulmonary disease (COPD), intraoperative airway driving pressure (∆p) > 15 mbar and positive endexpiratory pressure (PEEP) > 5 mbar, intraoperative administration of a long-acting opioids, first preoperative S_pO₂ < 97%, and last S_pO₂ < 97% measured after emergence from anesthesia before transport. At least 1 risk factor for postoperative hypoxemia was present in 90% of all patients. After propensity score matching, 3362 datasets per group remained for analysis of the influence of TM. Patients transported with TM revealed a higher S_pO₂ at PACU arrival (MM 97% [94; 99%], OM 96% [94; 99%], p < 0.001). In a subgroup analysis, this difference between groups remained in the presence of one or more risk factors (MM 97% [94; 99%], OM 96% [94; 98%], p < 0.001, n = 6044) but was not detectable in the absence of risk factors for hypoxemia (MM 97% [97; 100%], OM 99% [97; 100%], p < 0.393, n = 680). Furthermore, the goal of an Aldrete score > 8 at PACU arrival was achieved significantly more often in monitored patients (MM 2830 [83%], OM: 2665 [81%], p = 0.004). Critical hypoxemia (S_pO₂ < 90%) at PACU arrival had an overall low occurrence within propensity matched datasets and showed no difference between groups (MM: 161 [5%], OM 150 [5%], p = 0.755). According to these results, consistent use of TM leads to a higher S_pO₂ and Aldrete score at PACU arrival, even after a short transport distance within an operating room area. Consequently, it appears to be reasonable to avoid unmonitored transport after general anesthesia, even for short distances.

Comparison of Effects of Liuzijue Exercise and Conventional Respiratory Training on Patients after Cardiac Surgery: A Randomized Controlled Trial

OBJECTIVE

To evaluate the feasibility and safety of Liuzijue exercise (LE) for the clinical effect in patients after cardiac surgery.

METHODS

Totally 120 patients who underwent cardiac surgery and were admitted to the Cardiothoracic Intensive Care Unit of Nanjing Drum Tower Hospital between July and Oclober, 2022 were allocated to the LE group, the conventional respiratory training (CRT) group, and the control group by a random number table at a ratio of 1:1:1; 40 patients in each group. All patients received routine treatment and cardiac rehabilitation. LE group and CRT group respectively performed LE and CRT once a day for 30 min for 7 days. Control group did not receive specialized respiratory training. The forced vital capacity, forced expiratory volume in 1 s, peak inspiratory flow rate, peak expiratory flow rate, maximum inspiratory pressure, maximum expiratory pressure, modified Barthel index (MBI), and Hamilton Rating Scale for Anxiety (HAM-A) were evaluated before, after 3 and 7 days of intervention. In addition, the postoperative length of hospital stay (LOS) and the adverse events that occurred during the intervention period were compared.

RESULTS

A total of 107 patients completed the study, 120 patients were included in the analysis. After 3 days of intervention, the pulmonary function, respiratory muscle strength, MBI and HAM-A of all 3 groups improved compared with that before the intervention (P<0.05 or P<0.01). Compared with the control group, pulmonary function and respiratory muscle strength were significantly improved in the CRT and LE groups (P<0.05 or P<0.01). MBI and HAM-A were significantly improved in the LE group compared with the control and CRT groups (P<0.05 or P<0.01). On the 7th day after intervention, the difference was still statistically significant (P<0.01), and was significantly different from that on the 3rd day (P<0.05 or P<0.01). In addition, on the 7th day of intervention, the pulmonary function and respiratory muscle strength in the LE group were significantly improved compared with those in the CRT group (P<0.01). MBI and HAM-A were significantly improved in the CRT group compared with the control group (P<0.01). There were no significant differences in postoperative LOS among the 3 groups (P>0.05). No training-related adverse events occurred during the intervention period.

CONCLUSIONS

LE is safe and feasible for improving pulmonary function, respiratory muscle strength, the ability to complete activities of daily living and for relieving anxiety of patients after cardiac surgery (Registration No. ChiCTR2200062964).

A missed diagnosis of sputum crust with fiberoptic bronchoscope causing extubation failure: a case report

BACKGROUND

Fiberoptic bronchoscopy (FOB) and bronchoscopic biopsy are the established methods for diagnosing and treating sputum crust. However, sputum crust in concealed locations can sometimes be missed or undiagnosed, even with bronchoscopy.

CASE PRESENTATION

We present the case of a 44-year-old female patient who experienced initial extubation failure and postoperative pulmonary complications (PPCs) due to the missed diagnosis of sputum crust by FOB and low-resolution bedside chest X-ray. The FOB examination showed no apparent abnormalities prior to the first extubation, and the patient underwent tracheal extubation 2 h after aortic valve replacement (AVR). However, she was reintubated 13 h after the first extubation due to a persistent irritating cough and severe hypoxemia, and a bedside chest radiograph revealed pneumonia and atelectasis. Upon performing a repeat FOB examination prior to the second extubation, we serendipitously discovered the presence of sputum crust at the end of the endotracheal tube. Subsequently, we found that the sputum crust was mainly located on the tracheal wall between the subglottis and the end of the endotracheal tube during the "Tracheobronchial Sputum Crust Removal" procedure, and most of the crust was obscured by the retained endotracheal tube. The patient was discharged on the 20th day following therapeutic FOB.

CONCLUSION

FOB examination may miss specific areas in endotracheal intubation (ETI) patients, particularly the tracheal wall between the subglottis and distal end of the tracheal catheter, where sputum crust can be concealed. When diagnostic examinations with FOB are inconclusive, high-resolution chest CT can be helpful in identifying hidden sputum crust.

Intraoperative use of cell saver devices decreases the rate of hyperlactatemia in patients undergoing cardiac surgery

Objective

This study was aimed to elucidate the effect of the intraoperative cell saver (CS) on hyperlactatemia of patients who underwent cardiac surgery.

Design

A sub-analysis of the CS was performed, which is a historial control trial of patients undergoing cardiac surgery.

Setting

This was a retrospective single-center and not blinded study.

Participants

We examined the occurrence of hyperlactatemia retrospectively in patients of CS group (n = 78) who were included in prospective trial and received valvular surgery, where CS was used during the procedure. Patients subjected to valvular surgery before February 2021 were adopted in control group (n = 79).

Interventions

Arterial blood was sampled (1) before cardiopulmonary bypass, (2) during bypass (3) immediately after bypass, (4) on ICU admission and (5) every 4 h up to 24 h postoperatively.

Measurements and main results

A lower incidence of hyperlactatemia (32.1% vs. 57.0%; P = 0.001) was observed in patients from the CS group. Furthermore, the blood lactate concentration was higher in control group than in CS group during CPB, post CPB, on ICU admission and lasted until 20 h after the operation. Multivariable analysis revealed that intraoperative use of CS was expected to be a protective factor against hyperlactatemia in this study (OR = 0.31, 95% CI 0.15-0.63, P = 0.001).

Conclusion

Intraoperative use of a CS device was associated with a lower incidence of hyperlactatemia. Whether such device use is valuable to limiting hyperlactatemia in cardiac patients after surgery requires further evaluation in larger prospective studies.

Acute Lung Injury in aortic dissection : new insights in anesthetic management strategies

Acute aortic dissection (AAD) is a severe cardiovascular disease characterized by rapid progress and a high mortality rate. The incidence of acute aortic dissection is approximately 5 to 30 per 1 million people worldwide. In clinical practice, about 35% of AAD patients are complicated with acute lung injury (ALI). AAD complicated with ALI can seriously affect patients' prognosis and even increase mortality. However, the pathogenesis of AAD combined with ALI remains largely unknown. Given the public health burden of AAD combined with ALI, we reviewed the anesthetic management advances and highlighted potential areas for clinical practice.

Efficacy of prophylactic high-flow nasal cannula therapy for postoperative pulmonary complications after pediatric cardiac surgery: a prospective single-arm study

PURPOSE

This study investigated the incidence of postoperative pulmonary complications (PPC) when high-flow nasal cannula therapy (HFNC) is used prophylactically after pediatric cardiac surgery, and evaluated its efficacy.

METHODS

This was a single-arm prospective interventional study that was conducted in a tertiary teaching hospital with eight beds in the pediatric cardiac ICU after approval by the Ethics Committee. One-hundred children under the age of 48 months who were scheduled for cardiac surgery for congenital heart disease were recruited. HFNC was used for 24 h after extubation at a 2 L/kg/min flow rate. The primary outcome was the incidence of PPC within 48 h after extubation. PPC was defined as atelectasis and acute respiratory failure meeting certain criteria. We considered prophylactic HFNC as effective if the prevalence of PPC was < 10%, based on previous reports of reintubation rates of 6%-9% after pediatric cardiac surgery.

RESULTS

A total of 91 patients were finally included in the analysis. The incidence of PPC within 48 h after extubation was 18.7%, whereas atelectasis was observed in 13.2%, and acute respiratory failure in 8.8%. Reintubation rate within 48 h after extubation was 0%.

CONCLUSIONS

We found the incidence of PPC with prophylactic HFNC after planned extubation after pediatric cardiac surgery. However, the incidence was > 10%; therefore, we could not demonstrate its efficacy in this single-arm study. Further studies are needed to investigate whether the HFNC could be adapted as first-line oxygen therapy after pediatric cardiac surgery.

Comparison of Tools for Postoperative Pulmonary Complications After Cardiac Surgery

OBJECTIVES

To review the efficacy of 2 score tools for identifying pulmonary complications after cardiac surgery.

DESIGN

A retrospective observational study.

SETTING

At the West China Hospital of Sichuan University General Hospital.

PARTICIPANTS

Patients who underwent elective cardiac surgery (N = 508).

INTERVENTIONS

Not applicable.

MEASUREMENTS AND MAIN RESULTS

A total of 508 patients who underwent elective cardiac surgery between March 2021 and December 2021 were included in this observational study. Three independent physiotherapists used 2 different sets of score tools, as described by Kroenke et al. (Kroenke Score) and Reeve et al. (Melbourne Group Scale), to evaluate clinically defined pulmonary complications according to the European Perioperative Clinical Outcome definitions (including atelectasis, pneumonia, and respiratory failure) daily after surgery at midday. The incidence of postoperative pulmonary complications (PPCs) was 51.6% (262/508) with the Kroenke Score and 21.9% (111/508) with the Melbourne Group Scale. The clinically observed incidence of atelectasis was 51.4%, pneumonia was 20.9%, and respiratory failure at 6.5%. The receiver operator characteristics curve showed that the overall validity of the Kroenke Score was better than that of the Melbourne Group Scale in atelectasis (area under the curve [AUC], 91.5% v 71.3%). The Melbourne Group Scale performed better in pneumonia (AUC, 99.4% v 80.0%) and respiratory failure (AUC, 88.5% v 75.9%) than the Kroenke Score.

CONCLUSION

The incidence of PPCs after cardiac surgery was highly prevalent. Both the Kroenke Score and the Melbourne Group Scale are effective in identifying patients with PPCs. Kroenke Score can identify patients with mild pulmonary adverse events, whereas the Melbourne Group Scale is more dominant in identifying moderate-to-severe pulmonary complications.

Hyperoxemia During Cardiac Surgery Is Associated With Postoperative Pulmonary Complications

The use of hyperoxemia during cardiac surgery remains controversial. We hypothesized that intraoperative hyperoxemia during cardiac surgery is associated with an increased risk of postoperative pulmonary complications.

DESIGN

Retrospective cohort study.

SETTING

We analyzed intraoperative data from five hospitals within the Multicenter Perioperative Outcomes Group between January 1, 2014, and December 31, 2019. We assessed intraoperative oxygenation of adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Hyperoxemia pre and post CPB was quantified as the area under the curve (AUC) of Fio₂ above 0.21 in minutes when the corresponding peripheral oxygen saturation was greater than 92% measured by pulse oximetry. We quantified hyperoxemia during CPB as the AUC of Pao₂ greater than 200 mm Hg measured by arterial blood gas. We analyzed the association of hyperoxemia during all phases of cardiac surgery with the frequency of postoperative pulmonary complications within 30 days, including acute respiratory insufficiency or failure, acute respiratory distress syndrome, need for reintubation, and pneumonia.

PATIENTS

Twenty-one thousand six hundred thirty-two cardiac surgical patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During 21,632 distinct cardiac surgery cases, 96.4% of patients spent at least 1 minute in hyperoxemia (99.1% pre-CPB, 98.5% intra-CPB, and 96.4% post-CPB). Increasing exposure to hyperoxemia was associated with an increased risk of postoperative pulmonary complications throughout three distinct surgical periods. During CPB, increasing exposure to hyperoxemia was associated with an increased odds of developing postoperative pulmonary complications (p < 0.001) in a linear manner. Hyperoxemia before CPB (p < 0.001) and after CPB (p = 0.02) were associated with increased odds of developing postoperative pulmonary complications in a U-shaped relationship.

CONCLUSIONS

Hyperoxemia occurs almost universally during cardiac surgery. Exposure to hyperoxemia assessed continuously as an AUC during the intraoperative period, but particularly during CPB, was associated with an increased incidence of postoperative pulmonary complications.

Driving pressure-guided ventilation and postoperative pulmonary complications in thoracic surgery: a multicentre randomised clinical trial

BACKGROUND

Airway driving pressure, easily measured as plateau pressure minus PEEP, is a surrogate for alveolar stress and strain. However, the effect of its targeted reduction remains unclear.

METHODS

In this multicentre trial, patients undergoing lung resection surgery were randomised to either a driving pressure group (n=650) receiving an alveolar recruitment/individualised PEEP to deliver the lowest driving pressure or to a conventional protective ventilation group (n=650) with fixed PEEP of 5 cm H₂O. The primary outcome was a composite of pulmonary complications within 7 days postoperatively.

RESULTS

The modified intention-to-treat analysis included 1170 patients (mean [standard deviation, sd]; age, 63 [10] yr; 47% female). The mean driving pressure was 7.1 cm H₂O in the driving pressure group vs 9.2 cm H₂O in the protective ventilation group (mean difference [95% confidence interval, CI]; -2.1 [-2.4 to -1.9] cm H₂O; P<0.001). The incidence of pulmonary complications was not different between the two groups: driving pressure group (233/576, 40.5%) vs protective ventilation group (254/594, 42.8%) (risk difference -2.3%; 95% CI, -8.0% to 3.3%; P=0.42). Intraoperatively, lung compliance (mean [sd], 42.7 [12.4] vs 33.5 [11.1] ml cm H₂O^-1; P<0.001) and Pa_o2 (median [inter-quartile range], 21.5 [14.5 to 30.4] vs 19.5 [13.5 to 29.1] kPa; P=0.03) were higher and the need for rescue ventilation was less frequent (6.8% vs 10.8%; P=0.02) in the driving pressure group.

CONCLUSIONS

In lung resection surgery, a driving pressure-guided ventilation improved pulmonary mechanics intraoperatively, but did not reduce the incidence of postoperative pulmonary complications compared with a conventional protective ventilation.

CLINICAL TRIAL REGISTRATION

NCT04260451.

[The use of oscillatory respiratory therapy with positive expiratory pressure (PEP-therapy) to restore the functional state of the lungs in patients after cardiac surgery]

Postoperative pulmonary complications in cardiac surgery patients occur in 10-35% of cases, depending on differences in their definition, patient characteristics and type of surgical intervention, most of them are associated with ineffective coughing and evacuation of bronchial secretions.

OBJECTIVE

To determine the effectiveness of stimulating the evacuation of bronchial secretions with the help of oscillating PEP therapy carried out during the first three days.

MATERIAL AND METHODS

A randomized prospective study of 60 adult patients after elective cardiac surgery was performed (Clinical Trials.gov. protocol number NCT05159401). Oscillatory PEP-therapy was performed in 30 patients using Acapella DHGreen device (SmithMedicalASD, USA) 10-12 hours after tracheal extubation 3 times a day for 3 days after surgery. The control group (30 patients). The inclusion criteria: age over 18 years, spontaneous breathing after tracheal extubation, clear consciousness and productive contact with the patient, the ability to maintain adequate gas exchange on the low-flow oxygen inhalation, adequate analgesia (<2 points of VAS). Exclusion criteria: the need for re-intubation and mechanical ventilation, non-invasive mask ventilation, high-flow oxygen therapy, acute cerebrovascular accident, ongoing bleeding, cardiac insufficiency (inotropic index >10), shocks syndrome of various etiologies, the use of any extracorporeal support, any neuromuscular disorders, pneumothorax, hydro-or hemothorax. Before each session and 20 minutes after its end, when breathing air, blood oxygen saturation was recorded using a pulse oximeter (SpO2), the maximum inspiratory capacity (MIC) was measured using a Coach-2 incentive spirometer from SmithsMedical and spirometry with a portable ultrasonic spirometer Spiro Scout (Schiller, Switzerland). For the purposes of this work, the total index of the spirometry maximum inspiratory capacity (SMIC) was used - the sum of the respiratory volume and the reserve volume of inspiration in ml.

RESULTS

Difficulties in evacuation of sputum were noted in 90% of patients. Three-day sessions of oscillating PEP- therapy are accompanied by a significant improvement in the passage of sputum, as evidenced by a 3-fold increase in the number of patients with productive cough. The increase in MIC in the main group was 46.9% and 21.3%, respectively (p=0.042), and the number of patients with values greater than MICo. 1500 ml increased from 23.3% to 7.6% (p<0.001). The effectiveness of oscillatory PEP-therapy is confirmed by a 7-fold decrease in the frequency of radiological changes in the lungs at the end of sessions (p<0.001), while in the control group the frequency of their occurrence practically did not change and remained at a high level. The total number of patients with respiratory insufficiency (SpO2≤92%) decreased by 8.6 times after completion of all PEP- therapy sessions (p=0.001), however, without statistically significant difference with the control group.

CONCLUSIONS

Oscillatory PEP- therapy in cardiac surgery patients has a positive effect on sputum passage, ventilation parameters and oxygenating lung function. The procedure was well tolerated and there were no complications associated with it.

Comparison of the effects of different mechanical ventilation modes on the incidence of ventilation-associated pneumonia: a case study of patients undergoing thoracic surgery

OBJECTIVE

To investigate the effects of different mechanical ventilation modes on the incidence of ventilator-associated pneumonia (VAP) in patients undergoing thoracic surgery.

METHODS

From June 2019 to December 2021, the clinical data of 96 patients undergoing thoracic surgery in Cangzhou Central Hospital were retrospectively analyzed. A total of 44 patients who underwent constant flow mode were included in the control group (CG), and 52 patients who underwent auto flow mode were included in the observation group (OG). The respiratory mechanics, hemodynamics, blood gas analysis and serum levels of lung injury markers at different time points were compared between the two groups, and the incidence of VAP was analyzed.

RESULTS

At 1 hour and 4 hours of ventilation, the peak airway pressure (Ppeak), Pmean mean airway pressure (Pmean) and airway resistance (Raw) of the OG were lower than those of the CG, and the dynamic lung compliance (Cdyn) was higher than that of the CG (P<0.05). There were no statistically significant differences in mean arterial pressure (MAP), heart rate (HR), blood oxygen saturation (SpO₂), PH, arterial partial pressure of oxygen (PaO₂), arterial partial pressure of carbon dioxide (PaCO₂) between the OG and CG at 1 hour and 4 hours of ventilation respectively (P>0.05). The serum levels of pulmonary surfactant associated protein A (SP-A), human Clara cell protein (CC16) and serum ferritin (SF) in the OG were lower than those in the CG (P<0.05). The incidence of VAP in the OG (3.85%) was lower than that in the CG (15.91%) (P<0.05).

CONCLUSION

In mechanical ventilation, auto flow mode can reduce the incidence of VAP, improve respiratory mechanics, and reduce lung injury in patients undergoing thoracic surgery, but has no significant effect on hemodynamics and blood gas analysis.

Efficacy of perioperative intravenous lidocaine infusion on postoperative pulmonary complications in patients undergoing video-assisted thoracoscopic lung resection surgery: protocol for a randomised controlled trial

INTRODUCTION

Postoperative pulmonary complications (PPCs) are the most common complications following thoracoscopic surgery, resulting in increased hospital costs and perioperative mortality. Studies have shown that intravenous lidocaine infusion can exert its anti-inflammatory properties by reducing the release of proinflammatory cytokines. This study is designed to investigate whether intraoperative intravenous lidocaine infusion can reduce the incidence of PPCs in adult patients undergoing video-assisted thoracoscopic lung resection surgery.

METHODS AND ANALYSIS

This single-centre, double-blinded study will enrol 366 patients scheduled for video-assisted thoracoscopic lung resection surgery. Patients will be randomly assigned to the lidocaine or placebo infusion group in a 1: 1 ratio. The lidocaine group will receive lidocaine intravenously during the intraoperative period, while the placebo group will be administered normal saline at an equal volume, infusion rate and timing. The primary outcome is the incidence of PPCs within 7 days following surgery. The secondary outcomes are quality of postoperative recovery 40 scores; length of hospital stay (determined by the number of days from admission to discharge); incidence of moderate to severe pain within 24 and 48 hours at rest and when coughing; incidence of additional rescue analgesics use and incidence of adverse events.

ETHICS AND DISSEMINATION

The study was reviewed and approved by the Ethics Committee of Sichuan Provincial People's Hospital (approval no. 20222241). Written informed consent will be obtained from all patients before randomisation. The results of this trial will be disseminated in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ChiCTR2200061979.