Lung Injury After One-Lung Ventilation: A Review of the Pathophysiologic Mechanisms Affecting the Ventilated and the Collapsed Lung

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

OBJECTIVE

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

BACKGROUND

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

DESIGN

Randomized trial.

SETTING

Operating rooms and a post-anesthesia care unit.

PATIENTS

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

INTERVENTIONS

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

MEASUREMENTS

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

RESULTS

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

CONCLUSION

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Down-regulating lncRNA KCNQ1OT1 relieves type II alveolar epithelial cell apoptosis during one-lung ventilation via modulating miR-129-5p/HMGB1 axis induced pulmonary endothelial glycocalyx

OBJECTIVE

Endothelial glycocalyx (EG) maintains vascular homeostasis and is destroyed after one-lung ventilation (OLV)-induced lung injury. Long noncoding RNAs (lncRNAs) are critically involved in various lung injuries. This study aimed to investigate the role and regulatory mechanism of KCNQ1 overlapping transcript 1 (KCNQ1OT1) in OLV-induced lung injury and LPS-induced type II alveolar epithelial cell (AECII) apoptosis.

METHODS

The rat OLV model was established, and the effects of KCNQ1OT1 on OLV-induced ALI in vivo were explored. Bax and Caspase-3 expression in rat lung tissues was measured by immunochemistry (IHC). AECIIs were isolated from rat lungs and treated with LPS or normal saline (control) for in vitro analysis. The expression of KCNQ1OT1, miR-129-5p, and HMGB1 was measured by quantitative real-time PCR (qRT-PCR) or Western blot (WB). Cell proliferation and apoptosis were examined by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) and flow cytometry. The downstream targets of KCNQ1OT1 were predicted by bioinformatics, and the binding relationship between KCNQ1OT1 and miR-129-3p was verified by dual-luciferase reporter assays. The potential target of miR-129-5p was further explored on the Targetscan website and revealed to target HMGB1. Enzyme-linked immunosorbent assay (ELISA) or WB was adopted to determine the levels of IL-1β, TNF-α, MDA, SOD, heparanase (HPA), matrix metalloproteinase 9 (MMP9), heparan sulfate (HS) and syndecan-1 (SDC-1).

RESULTS

KCNQ1OT1 and HMGB1 were up-regulated during OLV-induced lung injury, and their expression was positively correlated. KCNQ1OT1 knockdown reduced OLV-induced pulmonary edema and lung epithelial cell apoptosis, increased vascular permeability, reduced IL-1β, TNF-α, MDA, and SOD levels and glycocalyx markers by targeting miR-129-5p or upregulating HMGB1. Overexpressing KCNQ1OT1 promoted cell apoptosis, reduced cell proliferation, aggravated inflammation and oxidative stress, and up-regulated HMGB1, HPA and MMP9 in LPS-treated AECIIs, while the HMGB1 silencing showed the opposite effects. MiR-129-5p mimics partially eliminated the KCNQ1OT1-induced effects, while recombinant HMGB1 restored the effects of miR-129-5p overexpression on AECIIs. Additionally, KCNQ1OT1 was demonstrated to promote the activation of the p38 MAPK/Akt/ERK signaling pathways in AECIIs via HMGB1.

CONCLUSION

KCNQ1OT1 knockdown alleviated AECII apoptosis and EG damage during OLV by targeting miR-129-5p/HMGB1 to inactivate the p38 MAPK/Akt/ERK signaling. The findings of our study might deepen our understanding of the molecular basis in OLV-induced lung injury and provide clues for the targeted disease management.

Intraoperative dexamethasone is associated with a lower risk of respiratory failure in thoracic surgery: Observational cohort study (SURTHODEX)

BACKGROUND

Postoperative complications, particularly respiratory complications, are of significant clinical concern in patients undergoing elective thoracic surgery. Dexamethasone (DXM), commonly administered to prevent postoperative nausea and vomiting (PONV), has potential anti-inflammatory effects that might be beneficial in reducing these complications. We aimed to investigate whether intraoperative DXM administration could mitigate the occurrence of respiratory complications following elective thoracic surgery.

METHODS

We conducted a single-center observational study, including patients who underwent elective thoracic surgery from 2012 to 2020. The primary outcome was the onset of acute respiratory failure within 7 days post-surgery. Secondary outcomes encompassed other postoperative complications, duration of hospital stay, and mortality within 30 days post-surgery. An overlap propensity score analysis was employed to estimate the treatment effect.

RESULTS

We included 1,247 adult patients, 897 who received dexamethasone (DXM) and 350 who served as controls. Intraoperative dexamethasone administration was associated with a significant reduction in respiratory complications with an adjusted relative risk (RR) of 0.65 (95% CI: 0.43-0.97). There was also a significant decline in composite infectious criteria with an adjusted RR of 0.76 (95% CI: 0.63-0.93). Cardiac complications were also assessed as a composite criterion, and a significant reduction was observed (adjusted RR, 0.68; 95% CI, 0.51-0.9). However, there were no association with mechanical complications, mortality within 30 days (adjusted RR of 0.43, 95% CI: 0.17-1.09) or in the length of hospital stay (adjusted RR of 0.85, 95% CI: 0.71-1.02).

CONCLUSIONS

Dexamethasone administration was associated with a reduction in postoperative respiratory complications. Further prospective studies are needed to confirm these findings.

A Comparative Evaluation of Unilateral and Bilateral Sequential Lung Isolation for Vertebral Body Tethering: A Retrospective Propensity Matched Analysis

BACKGROUND

Vertebral body tethering (VBT) requires a thoracoscopic approach to visualize the vertebral bodies. Lung collapse and re-expansion have the potential to cause acute lung injury, resulting in increased oxygen and ventilation requirements.

AIMS

We compared the intraoperative ventilator management, intra- and postoperative blood gas determinations, and hospital stay information between adolescents undergoing unilateral versus bilateral lung isolation for vertebral body tethering.

METHODS

 A study cohort of 132 propensity-matched cases (66 unilateral and 66 bilateral) was derived from 351 consecutive VBT cases. Patient demographic information, case information, fluid administration, ventilatory settings data, blood gas parameters, and complete blood count and differential data were entered into a datasheet. Derived parameters included values calculated from the alveolar gas equation to develop an oxygen cascade and measures of inflammatory response. Chi-square was used for categorical data, and independent samples and t-tests were used for continuous data.

RESULTS

The double lung isolation group required higher peak inspiratory pressures (SL 29±5 vs. DL 31±5, p=0.026), resulting in higher tidal volume (SL 246±63 vs. DL 334±101, p<0.001) and tidal volume per kg (SL 5.6±1.4 vs. DL 6.9±2, p<0.001) as compared to the single lung group. The double lung group required a higher partial pressure of inspired and alveolar oxygen as well as a higher alveolar to arterial oxygen tension gradient (SL 417±126 vs. DL 485±96, p=0.001) to achieve optimal arterial oxygen tension. Patients with double lung isolation had similar intensive care lengths of stay but a longer hospital stay than single lung isolation patients.

CONCLUSION

Patients undergoing double lung isolation required greater ventilatory support and had more evidence of acute lung injury, as evidenced by a higher postoperative alveolar to arterial oxygen gradient; however, these healthy adolescents tolerated the procedure well and only differed in the hospital length of stay by a day.

Dexmedetomidine improves pulmonary outcomes in thoracic surgery under one-lung ventilation: A meta-analysis

INTRODUCTION

Dexmedetomidine improves intrapulmonary shunt in thoracic surgery and minimizes inflammatory response during one-lung ventilation (OLV). However, it is unclear whether such benefits translate into less postoperative pulmonary complications (PPCs). Our objective was to determine the impact of dexmedetomidine on the incidence of PPCs after thoracic surgery.

METHODS

Major databases were used to identify randomized trials that compared dexmedetomidine versus placebo during thoracic surgery in terms of PPCs. Our primary outcome was atelectasis within 7 days after surgery. Other specific PPCs included hypoxemia, pneumonia, and acute respiratory distress syndrome (ARDS). Secondary outcome included intraoperative respiratory mechanics (respiratory compliance [Cdyn]) and postoperative lung function (forced expiratory volume [FEV1]). Random effects models were used to estimate odds ratios (OR).

RESULTS

Twelve randomized trials, including 365 patients in the dexmedetomidine group and 359 in the placebo group, were analyzed in this meta-analysis. Patients in the dexmedetomidine group were less likely to develop postoperative atelectasis (2.3% vs 6.8%, OR 0.42, 95%CI 0.18-0.95, P = 0.04; low certainty) and hypoxemia (3.4% vs 11.7%, OR 0.26, 95%CI 0.10-0.68, P = 0.01; moderate certainty) compared to the placebo group. The incidence of postoperative pneumonia (3.2% vs 5.8%, OR 0.57, 95%CI 0.25-1.26, P = 0.17; moderate certainty) or ARDS (0.9% vs 3.5%, OR 0.39, 95%CI 0.07-2.08, P = 0.27; moderate certainty) was comparable between groups. Both intraoperative Cdyn and postoperative FEV1 were higher among patients that received dexmedetomidine with a mean difference of 4.42 mL/cmH2O (95%CI 3.13-5.72) and 0.27 L (95%CI 0.12-0.41), respectively.

CONCLUSION

Dexmedetomidine administration during thoracic surgery may potentially reduce the risk of postoperative atelectasis and hypoxemia. However, current evidence is insufficient to demonstrate an effect on pneumonia or ARDS.

Comparison of ICG-Guided Near-Infrared Fluorescence Imaging and Modified Inflation-Deflation Method in Identifying the Intersegmental Plane During Lung Segmentectomy of Infants

BACKGROUND

The identification of the intersegmental plane (ISP) is a crucial step in segmentectomy for children with congenital pulmonary airway malformation (CPAM) due to complex anatomical variations. However, there is very limited literature available on this aspect specifically for infant. In this study, we compared the intravenous indocyanine green (ICG)-guided near-infrared fluorescence (NIRF) imaging method with the modified inflation-deflation method in terms of their perioperative characteristics and summarized our experience.

METHODS

From June 2021 to November 2022, the data of 83 patients with CPAM who underwent segmentectomy by video-assisted thoracoscopic surgery were retrospectively reviewed. Twenty-eight patients underwent ICG-guided NIRF method, and 56 patients underwent the modified inflation-deflation method, characteristics and clinical outcomes were compared.

RESULTS

The median age of the patients was 4.99 months (4.99 ± 1.51) with a mean body weight of 7.54 kg (7.54 ± 1.99). Both methods could accurately identify the ISP. The time taken to clearly display the ISP was shorter in ICG group than in the modified inflation-deflation group (0.18 ± 0.08 vs. 6.49 ± 1.67 min; P < 0.001), and the surgical duration (61.32 ± 14.28 vs. 88.18 ± 8.03 min; P < 0.001) were significantly shorter in the ICG group too. The two groups exhibited differences in the length of chest tube drainage (1.75 ± 1.24 vs. 2.36 ± 1.54 days; P = 0.072) and the length of hospital stay (4.61 ± 1.75 vs. 5.20 ± 3.07 days; P = 0.078), however, the differences were not statistically significant. There were no significant differences between the two groups in the blood lost and postoperative complications. At a follow-up of more than 1 year after operation, all patients had recovered well without recurrence.

CONCLUSIONS

According to our experience, the ICG-guided NIRF method was safe and feasible for infants during thoracoscopic segmentectomy, it can quickly display the ISP and shorten the surgical duration compared with the modified inflation-deflation method.

Dexmedetomidine improves lung injury after one-lung ventilation in esophageal cancer patients by inhibiting inflammatory response and oxidative stress

Aim

To explore the effect of Dexmedetomidine (DEX) on lung injury in patients undergoing One-lung ventilation (OLV).

Methods

Esophageal cancer patients undergoing general anesthesia with OLV were randomly divided into the DEX group and control group, with 30 cases in each group. Mean arterial pressure (MAP), heart rate (HR), arterial partial pressure of oxygen (PO2), and arterial partial pressure of nitrogen dioxide (PCO2) were recorded at the time points after anesthesia induction and before OLV (T1), OLV 30 min (T2), OLV 60 min (T3), OLV 120 min (T4), OLV end before (T5) and before leaving the room (T6) in both groups. Reverse Transcription-Polymerase Chain Reaction (RT-qPCR) was applied to detect the levels of CC16 mRNA. Enzyme-linked immunosorbent assay (ELISA) was used to detect serum CC16 protein levels. The content of malondialdehyde (MDA) in serum was determined by thio barbituric acid (TBA) method. ELISA was used to measure the concentrations of TNF-α (tumor necrosis factor-alpha)/and IL-6 (interleukin 6).

Results

DEX treatment slowed down HR at time points T1-T6 and increased PO2 and PCO2 at time points T2-T5 compared with the control group. Moreover, at time points T2-T6, DEX treatment reduced the levels of club cell secretory protein-16 (CC16) mRNA and serum CC16 protein levels. Furthermore, DEX treatment caused the reduction of MDA, TNF-α and IL-6 concentrations in serum of patients.

Conclusion

During the OLV process, DEX could reduce serum CC16 protein levels, inhibit inflammatory reactions and oxidative stress, and improve oxygenation index, indicating a protective effect on lung injury during OLV.

Continuous positive airway pressure combined with small-tidal-volume ventilation on arterial oxygenation and pulmonary shunt during one-lung ventilation in patients undergoing video-assisted thoracoscopic lobectomy: A randomized, controlled study

BACKGROUND

One-lung ventilation (OLV) is frequently applied during video-assisted thoracoscopic surgery (VATS) airway management to collapse and isolate the nondependent lung (NL). OLV can give rise to hypoxemia as a result of the pulmonary shunting produced. Our study aimed to assess the influence of continuous positive airway pressure (CPAP) combined with small-tidal-volume ventilation on improving arterial oxygenation and decreasing pulmonary shunt rate (QS/QT) without compromising surgical field exposure during OLV.

METHODS

Forty-eight patients undergoing scheduled VATS lobectomy were enrolled in this research and allocated into three groups at random: C group (conventional ventilation, no NL ventilation intervention was performed), LP group (NL was ventilated with lower CPAP [2 cmH2O] and a 40-60 mL tidal volume [TV]), and HP group (NL was ventilated with higher CPAP [5 cmH2O] and a 60-80 mL TV). Record the blood gas analysis data and calculate the QS/QT at the following time: at the beginning of the OLV (T0), 30 min after OLV (T1), and 60 min after OLV (T2). Surgeons blinded to ventilation techniques were invited to evaluate the surgical fields.

RESULTS

The demography data of the three groups were consistent with the surgical data. At T1, PaO2 in the HP group was substantially higher compared to the C group (P < 0.05), while there was no significant difference in the LP group (P > 0.05). At T1-T2, PaCO2 in the LP and HP groups was significantly less than that in the C group (P < 0.05). At T1, the QS/QT values of groups C, LP, and HP were 29.54 ± 6.89%, 22.66 ± 2.08%, and 19.64 ± 5.76%, respectively, and the QS/QT values in the LP and HP groups markedly reduced (P < 0.01). The surgical field's evaluation by the surgeon among the three groups was not notable (P > 0.05).

CONCLUSION

CPAP combined with small-tidal-volume ventilation effectively improved arterial oxygenation and reduced QS/QT and PaCO2 without compromising surgical field exposure during OLV. Among them, 5 cmH2O CPAP + 60-80 ml TV ventilation had a better effect on improving oxygenation.

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

BACKGROUND

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

METHODS

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

FINDINGS

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

INTERPRETATION

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

FUNDING

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

Facilitating Lung Collapse for Thoracoscopic Surgery Utilizing Endobronchial Airway Occlusion Preceded by Pleurotomy and One-minute Suspension of Two-lung Ventilation

OBJECTIVES

To assess when and whether clamping the double-lumen endobronchial tube (DLT) limb of the non-ventilated lung is more conducive to a rapid and effective lung deflation than simply allowing the open limb of the DLT to communicate with the atmosphere.

DESIGN

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

SETTING

The trial was performed in a single institutional setting.

PARTICIPANTS

The participants were 60 patients undergoing elective video-assisted thoracoscopic surgery.

INTERVENTIONS

Patients were randomized to the open-clamp airway technique (OCAT group) or control group. Patients in the control group had one-lung ventilation initiated upon being placed in the lateral decubitus position. The OCAT group had two-lung ventilation maintained until the pleural cavity was opened with the introduction of a planned thoracoscopic access port to allow the operated lung to fall away from the chest wall. Thereafter, ventilation was suspended (temporarily ceased) for 1 minute before the DLT lumen of the isolated lung was clamped. The primary outcome of the trial was the time to complete lung collapse scored as determined from video clips taken during surgery. The secondary outcomes were (1) lung collapse score at 30 minutes after pleural incision, (2) surgeon satisfaction with surgery, and (3) intraoperative hypoxemia.

MEASUREMENTS AND MAIN RESULTS

The median time to reach complete lung collapse in the OCAT group was 10 minutes (odds ratio 10.0, 95% CI 6.3-13.7), which was much shorter than that of the control group (25 minutes [odds ratio 25.0, 95% CI 13.6-36.4]). The difference in complete lung collapse at 30 minutes between the 2 groups was significant (p < 0.001). The surgeon's satisfaction with surgery was higher in the OCAT group than in the control group (8.5 ± 0.2 vs 6.8 ± 0.2; p < 0.001). There was no difference regarding intraoperative hypoxemia.

CONCLUSIONS

Suspending ventilation of both DLT limbs for 1 minute after pleural cavity opening and then clamping the DLT lumen of the isolated lung resulted in a more rapid deflation of the surgical lung. This open-clamp airway technique is an effective technique for rapid surgical lung collapse during thoracoscopic surgery.

Recovery and Survival of Patients After Out-of-Hospital Cardiac Arrest: A Literature Review Showcasing the Big Picture of Intensive Care Unit-Related Factors

As an important public health issue, out-of-hospital cardiac arrest (OHCA) requires several stages of high quality medical care, both on-field and after hospital admission. Post-cardiac arrest shock can lead to severe neurological injury, resulting in poor recovery outcome and increased risk of death. These characteristics make this condition one of the most important issues to deal with in post-OHCA patients hospitalized in intensive care units (ICUs). Also, the majority of initial post-resuscitation survivors have underlying coronary diseases making revascularization procedure another crucial step in early management of these patients. Besides keeping myocardial blood flow at a satisfactory level, other tissues must not be neglected as well, and maintaining mean arterial pressure within optimal range is also preferable. All these procedures can be simplified to a certain level along with using targeted temperature management methods in order to decrease metabolic demands in ICU-hospitalized post-OHCA patients. Additionally, withdrawal of life-sustaining therapy as a controversial ethical topic is under constant re-evaluation due to its possible influence on overall mortality rates in patients initially surviving OHCA. Focusing on all of these important points in process of managing ICU patients is an imperative towards better survival and complete recovery rates.

Thoracic paravertebral block for perioperative lung preservation during VATS pulmonary surgery: study protocol of a randomized clinical trial

BACKGROUND

Postoperative pulmonary complications (PPCs) extend the length of stay of patients and increase the perioperative mortality rate after video-assisted thoracoscopic (VATS) pulmonary surgery. Thoracic paravertebral block (TPVB) provides effective analgesia after VATS surgery; however, little is known about the effect of TPVB on the incidence of PPCs. The aim of this study is to determine whether TPVB combined with GA causes fewer PPCs and provides better perioperative lung protection in patients undergoing VATS pulmonary surgery than simple general anaesthesia.

METHODS

A total of 302 patients undergoing VATS pulmonary surgery will be randomly divided into two groups: the paravertebral block group (PV group) and the control group (C group). Patients in the PV group will receive TPVB: 15 ml of 0.5% ropivacaine will be administered to the T4 and T7 thoracic paravertebral spaces before general anaesthesia induction. Patients in the C group will not undergo the intervention. Both groups of patients will be subjected to a protective ventilation strategy during the operation. Perioperative protective mechanical ventilation and standard fluid management will be applied in both groups. Patient-controlled intravenous analgesia is used for postoperative analgesia. The primary endpoint is a composite outcome of PPCs within 7 days after surgery. Secondary endpoints include blood gas analysis, postoperative lung ultrasound score, NRS score, QoR-15 score, hospitalization-related indicators and long-term prognosis indicators.

DISCUSSION

This study will better evaluate the impact of TPVB on the incidence of PPCs and the long-term prognosis in patients undergoing VATS lobectomy/segmentectomy. The results may provide clinical evidence for optimizing perioperative lung protection strategies.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05922449 . Registered on June 25, 2023.

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

BACKGROUND

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

METHODS

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

DISCUSSION

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

TRIAL REGISTRATION

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Non-intubated versus intubated video-assisted thoracoscopic lobectomy for lung cancer patients

INTRODUCTION

Video-assisted thoracoscopic surgery (VATS) lobectomy has been shown to be a standard treatment for lung cancer patient due to less pain, post-operative complication and faster recovery. In recent years, Non-intubated video-assisted thoracoscopic surgery (NIVATS) is become an alternative approach for various types of thoracic surgery with a benefit on fewer complication from mechanical ventilation. Out study is aimed to study outcome compare between NIVATS lobectomy and to general anesthetic video assisted thoracoscopic surgery (GAVATS) lobectomy.

METHODS

This is a retrospective cohort study conduct in Vajira hospital, Navamindradhiraj University, Bangkok, Thailand between January 2019 to September 2022.152 lung cancer patients underwent lobectomy. However, lung cancer patients whom needed to convert to GAVATS, open thoracotomy or emergency surgery were excluded from this study. In this study, we compare lung patients whom underwent NIVATS lobectomy and those whom underwent GAVATS lobectomy. These two groups are compared in term of pre-, intra- and post-operative outcomes. The inverse-probability weighting propensity score is used to identify the treatment effects of NIVATS.

RESULTS

In total, there are 132 cases patients including in this analysis. There are 54 and 78 patients in the NIVATS and GAVATS respectively. Intra-operative outcome, induction and operative time are lower in the NIVATS lobectomy group (25 vs 30 min, p < 0.001 and 90 vs 120 min, p = 0.003). There is no difference regarding number of node resection, station of lymph node dissection, arrhythmia, postoperative complications, and pain visual analogue score (VAS) in both groups. Postoperative outcome, length of hospital stay is shorter in NIVATS lobectomy group (4 vs 5 days, p < 0.001). There is no patient which needed to convert from NIVATS to GAVATS. The treatment-effect analyzed by using inverse-probability weighting propensity score has shown benefits of NIVATS in terms of shorter hospital stays (coefficient -2.31, 95%CI -3.65 to -0.97, p = 0.001), and shorter chest tube duration (coefficient -1.59, 95%CI -2.93 to -0.26, p = 0.019).

CONCLUSION

NIVATS lobectomy could be an alternative approach for lung cancer patients with benefits of lesser in hospital stays and duration of chest tube.

Predictors of acute kidney injury after lung resection surgery: a retrospective case-control study

PURPOSE

Patients undergoing lung resection are at increased risk for acute kidney injury (AKI) in the immediate postoperative period, with important consequences for longer term morbidity and mortality. Lung resection surgery has unique considerations that could increase the risk of AKI, including lung resection volume, duration of one-lung ventilation (OLV), and intraoperative fluid restriction. Yet, specific risk factor data are lacking. The objective of this study was to identify independent risk factors for early AKI after lung resection surgery.

METHODS

We conducted a retrospective case-control study of all patients presenting for elective lung resection surgery at an academic medical centre over a four-year period. Cases were patients who experienced an AKI and control patients were those who did not experience an AKI, based on KDIGO criteria. Baseline demographics and comorbidities along with duration of OLV and amount of lung resected were collected by retrospective chart review. The data were analyzed using multivariable logistic regression to identify independent predictors of AKI.

RESULTS

Acute kidney injury occurred within 48 hr in 57/1,045 (5.5%; 95% confidence interval, 4.2 to 7.0) of patients. On multivariable analysis, our model of best fit included preoperative serum creatinine, male sex, use of angiotensin II receptor blockers, and duration of OLV. The rate of complications, intensive care unit admission, and risk of death were all higher in the group of patients who experienced AKI.

CONCLUSIONS

Acute kidney injury occurs frequently after lung resection surgery and is associated with increased risk of postoperative complications. Increased duration of OLV may be a risk factor for AKI in this population.

A novel nomogram for predicting the decision to delayed extubation after thoracoscopic lung cancer surgery

OBJECTIVE

Delayed extubation was commonly associated with increased adverse outcomes. This study aimed to explore the incidence and predictors and to construct a nomogram for delayed extubation after thoracoscopic lung cancer surgery.

METHODS

We reviewed medical records of 8716 consecutive patients undergoing this surgical treatment from January 2016 to December 2017. Using potential predictors to develop a nomogram and using a bootstrap-resampling approach to conduct internal validation. For external validation, we additionally pooled 3676 consecutive patients who underwent this procedure between January 2018 and June 2018. Extubation performed outside the operating room was defined as delayed extubation.

RESULTS

The rate of delayed extubation was 1.60%. Multivariate analysis identified age, BMI, FEV₁/FVC, lymph nodes calcification, thoracic paravertebral blockade (TPVB) usage, intraoperative transfusion, operative time and operation later than 6 p.m. as independent predictors for delayed extubation. Using these eight candidates to develop a nomogram, with a concordance statistic (C-statistic) value of 0.798 and good calibration. After internal validation, similarly good calibration and discrimination (C-statistic, 0.789; 95%CI, 0.748 to 0.830) were observed. The decision curve analysis (DCA) indicated the positive net benefit with the threshold risk range of 0 to 30%. Goodness-of-fit test and discrimination in the external validation were 0.113 and 0.785, respectively.

CONCLUSION

The proposed nomogram can reliably identify patients at high risk for the decision to delayed extubation after thoracoscopic lung cancer surgery. Optimizing four modifiable factors including BMI, FEV₁/FVC, TPVB usage, and operation later than 6 p.m. may reduce the risk of delayed extubation.Key Messages:This study identified eight independent predictors for delayed extubation, among which lymph node calcification and anaesthesia type were not commonly reported.Using these eight candidates to develop a nomogram, we could reliably identify high-risk patients for the decision to delayed extubation.Optimizing four modifiable factors, including BMI, FEV₁/FVC, TPVB usage, and operation later than 6 p.m. may reduce the risk of delayed extubation.

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.

Playing the pipes: acoustic sensing and machine learning for performance feedback during endotracheal intubation simulation

Objective: In emergency medicine, airway management is a core skill that includes endotracheal intubation (ETI), a common technique that can result in ineffective ventilation and laryngotracheal injury if executed incorrectly. We present a method for automatically generating performance feedback during ETI simulator training, potentially augmenting training outcomes on robotic simulators. Method: Electret microphones recorded ultrasonic echoes pulsed through the complex geometry of a simulated airway during ETI performed on a full-size patient simulator. As the endotracheal tube is inserted deeper and the cuff is inflated, the resulting changes in geometry are reflected in the recorded signal. We trained machine learning models to classify 240 intubations distributed equally between six conditions: three insertion depths and two cuff inflation states. The best performing models were cross validated in a leave-one-subject-out scheme. Results: Best performance was achieved by transfer learning with a convolutional neural network pre-trained for sound classification, reaching global accuracy above 98% on 1-second-long audio test samples. A support vector machine trained on different features achieved a median accuracy of 85% on the full label set and 97% on a reduced label set of tube depth only. Significance: This proof-of-concept study demonstrates a method of measuring qualitative performance criteria during simulated ETI in a relatively simple way that does not damage ecological validity of the simulated anatomy. As traditional sonar is hampered by geometrical complexity compounded by the introduced equipment in ETI, the accuracy of machine learning methods in this confined design space enables application in other invasive procedures. By enabling better interaction between the human user and the robotic simulator, this approach could improve training experiences and outcomes in medical simulation for ETI as well as many other invasive clinical procedures.

Effect of remote ischemic preconditioning on lung function after surgery under general anesthesia: a systematic review and meta-analysis

Remote ischemic preconditioning (RIPC) protects organs from ischemia-reperfusion injury. Recent trials showed that RIPC improved gas exchange in patients undergoing lung or cardiac surgery. We performed a systematic search to identify randomized controlled trials involving RIPC in surgery under general anesthesia. The primary outcome was the PaO2/FIO2 (P/F) ratio at 24 h after surgery. Secondary outcomes were A-a DO2, the respiratory index, duration of postoperative mechanical ventilation (MV), incidence of acute respiratory distress syndrome (ARDS), and serum cytokine levels. The analyses included 71 trials comprising 7854 patients. Patients with RIPC showed higher P/F ratio than controls (mean difference [MD] 36.6, 95% confidence interval (CI) 12.8 to 60.4, I2 = 69%). The cause of heterogeneity was not identified by the subgroup analysis. Similarly, A-a DO2 (MD 15.2, 95% CI - 29.7 to - 0.6, I2 = 87%) and respiratory index (MD - 0.17, 95% CI - 0.34 to - 0.01, I2 = 94%) were lower in the RIPC group. Additionally, the RIPC group was weaned from MV earlier (MD - 0.9 h, 95% CI - 1.4 to - 0.4, I2 = 78%). Furthermore, the incidence of ARDS was lower in the RIPC group (relative risk 0.73, 95% CI 0.60 to 0.89, I2 = 0%). Serum TNFα was lower in the RIPC group (SMD - 0.6, 95%CI - 1.0 to - 0.3 I2 = 87%). No significant difference was observed in interleukin-6, 8 and 10. Our meta-analysis suggested that RIPC improved oxygenation after surgery under general anesthesia.Clinical trial number: This study protocol was registered in the University Hospital Medical Information Network (registration number: UMIN000030918), https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000035305.

Spontaneous Ventilation Combined with Double-Lumen Tube Intubation during Thoracic Surgery: A New Anesthesiologic Method Based on 141 Cases over Three Years

BACKGROUND

Non-intubated thoracic surgery has not achieved widespread acceptance despite its potential to improve postoperative outcomes. To ensure airway safety, our institute has developed a technique combining spontaneous ventilation with double-lumen tube intubation (SVI). This study aimed to verify the feasibility and limitations of this SVI technique.

METHODS

For the SVI method, anesthesia induction involves fentanyl and propofol target-controlled infusion, with mivacurium administration. Bispectral index monitoring was used to ensure the optimal depth of anesthesia. Short-term muscle relaxation facilitated double-lumen tube intubation and early surgical steps. Chest opening preceded local infiltration, followed by a vagal nerve blockade to prevent the cough reflex and a paravertebral blockade for pain relief. Subsequently, the muscle relaxant was ceased. The patient underwent spontaneous breathing without coughing during surgical manipulation.

RESULTS

Between 10 March 2020 and 28 October 2022, 141 SVI surgeries were performed. Spontaneous respiration with positive end-expiratory pressure was sufficient in 65.96% (93/141) of cases, whereas 31.21% (44/141) required pressure support ventilation. Only 2.84% (4/141) of cases reversed to conventional anesthetic management, owing to technical or surgical difficulties. Results of the 141 cases: The mean maximal carbon dioxide pressure was 59.01 (34.4-92.9) mmHg, and the mean lowest oxygen saturation was 93.96% (81-100%). The mean one-lung, mechanical and spontaneous one-lung ventilation time was 74.88 (20-140), 17.55 (0-115) and 57.73 (0-130) min, respectively.

CONCLUSIONS

Spontaneous ventilation with double-lumen tube intubation is safe and feasible for thoracic surgery. The mechanical one-lung ventilation time was reduced by 76.5%, and the rate of anesthetic conversion to relaxation was low (2.8%).

Awake uniportal video-assisted thoracoscopic surgery for the management of pericardial effusion

Introduction

Pericardial drainage can be performed either with pericardiocentesis or pericardial "window" in cases with hemodynamic compromise for therapeutic and diagnostic purposes. Awake single-port video-assisted thoracoscopic surgery (VATS) is an alternative to pericardial window (PW) that has been described only in case reports in the literature. We aimed to analyse a series of patients with chronic, recurrent and/or large pericardial effusions who underwent single-port VATS-PW opening without intubation.

Patients and Methods

The PW was opened using awake single-port VATS in 20 of 23 patients referred to our clinic with recurrent, chronic and/or large pericardial effusion between December 2021 and July 2022. Demographic data, imaging modalities, treatment processes and pathological samples were analysed retrospectively.

Results

The median age of 20 patients was 68 years (52-81). The mean body mass index was 29.1 ± 6.0 kg/m2 and mean pericardial fluid measurements with pre-operative transthoracic echocardiography (TTE) was 2,8 ± 0,9 cm. The mean operation time was 44 ± 13.0 min and mean peri-operative drainage was 700 ± 307 cc. On the 1st post-operative day, control TTE revealed ≤0.5 cm effusion in 18 (90%) patients and ≥0.5 cm in 2 (10%) patients. The median day of discharge or referral to the clinic where they are followed up was 1 (1-2).

Conclusions

Awake single-port VATS could be used safely in all patient groups with pericardial effusion or tamponade as a diagnostic and therapeutic option. This technique has advantages, especially in patients with high surgical risk.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

Prospective randomised controlled trial.

SETTING

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

PATIENTS

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

INTERVENTION

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

MAIN OUTCOME MEASURES

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

NCT04175379.

Distribution of transpulmonary pressure during one-lung ventilation in pigs at different body positions

Background. Global and regional transpulmonary pressure (PL) during one-lung ventilation (OLV) is poorly characterized. We hypothesized that global and regional PL and driving PL (ΔPL) increase during protective low tidal volume OLV compared to two-lung ventilation (TLV), and vary with body position. Methods. In sixteen anesthetized juvenile pigs, intra-pleural pressure sensors were placed in ventral, dorsal, and caudal zones of the left hemithorax by video-assisted thoracoscopy. A right thoracotomy was performed and lipopolysaccharide administered intravenously to mimic the inflammatory response due to thoracic surgery. Animals were ventilated in a volume-controlled mode with a tidal volume (VT) of 6 mL kg-1 during TLV and of 5 mL kg-1 during OLV and a positive end-expiratory pressure (PEEP) of 5 cmH2O. Global and local transpulmonary pressures were calculated. Lung instability was defined as end-expiratory PL<2.9 cmH2O according to previous investigations. Variables were acquired during TLV (TLVsupine), left lung ventilation in supine (OLVsupine), semilateral (OLVsemilateral), lateral (OLVlateral) and prone (OLVprone) positions randomized according to Latin-square sequence. Effects of position were tested using repeated measures ANOVA. Results. End-expiratory PL and ΔPL were higher during OLVsupine than TLVsupine. During OLV, regional end-inspiratory PL and ΔPL did not differ significantly among body positions. Yet, end-expiratory PL was lower in semilateral (ventral: 4.8 ± 2.9 cmH2O; caudal: 3.1 ± 2.6 cmH2O) and lateral (ventral: 1.9 ± 3.3 cmH2O; caudal: 2.7 ± 1.7 cmH2O) compared to supine (ventral: 4.8 ± 2.9 cmH2O; caudal: 3.1 ± 2.6 cmH2O) and prone position (ventral: 1.7 ± 2.5 cmH2O; caudal: 3.3 ± 1.6 cmH2O), mainly in ventral (p ≤ 0.001) and caudal (p = 0.007) regions. Lung instability was detected more often in semilateral (26 out of 48 measurements; p = 0.012) and lateral (29 out of 48 measurements, p < 0.001) as compared to supine position (15 out of 48 measurements), and more often in lateral as compared to prone position (19 out of 48 measurements, p = 0.027). Conclusion. Compared to TLV, OLV increased lung stress. Body position did not affect stress of the ventilated lung during OLV, but lung stability was lowest in semilateral and lateral decubitus position.

Hyperoxemia post thoracic surgery - Does it matter?

Introduction

Post-operative oxygen therapy is used to prevent hypoxemia and surgical site infection. However, with improvements of anesthesia techniques, post-operative hypoxemia incidence is declining and the benefits of oxygen on surgical site infection have been questioned. Moreover, hyperoxemia might have adverse effects on the pulmonary and cardiovascular systems. We hypothesized hyperoxemia post thoracic surgery is associated with post-operative pulmonary and cardiovascular complications.

Methods

Consecutive lung resection patients were included in this post-hoc analysis. Post-operative pulmonary and cardiovascular complications were prospectively assessed during the first 30 post-operative days, or hospital stay. Arterial blood gases were analyzed at 1, 6 and 12 h after surgery. Hyperoxemia was defined as arterial partial pressure of oxygen (PaO₂)>100 mmHg. Patients with hyperoxemia duration in at least two adjacent time points were considered as hyperoxemic. Student t-test, Mann-Whitney U test and two-tailed Fisher exact test were used for group comparison. P values < 0.05 were considered statistically significant.

Results

Three hundred sixty-three consecutive patients were included in this post-hoc analysis. Two hundred five patients (57%), were considered hyperoxemic and included in the hyperoxemia group. Patients in the hyperoxemia group had significantly higher PaO₂ at 1, 6 and 12 h after surgery (p < 0.05). Otherwise, there was no significant difference in age, sex, comorbidities, pulmonary function tests parameters, lung surgery procedure, incidence of post-operative pulmonary and cardiovascular complications, intensive care unit and hospital length of stay and 30-day mortality.

Conclusion

Hyperoxemia after lung resection surgery is common and not associated with post-operative complications or 30-day mortality.

Lung recruitment by continuous negative extra-thoracic pressure support following one-lung ventilation: an experimental study

Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV. We investigated the effects of CNEP following OLV on lung expansion, gas exchange, and hemodynamics. Ten pigs were anesthetized and mechanically ventilated with pressure-regulated volume control mode (PRVC; FiO₂: 0.5, Fr: 30-35/min, VT: 7 mL/kg, PEEP: 5 cmH₂O) for 1 hour, then baseline (BL) data for gas exchange (arterial partial pressure of oxygen, PaO₂; and carbon dioxide, PaCO₂), ventilation and hemodynamical parameters and lung aeration by electrical impedance tomography were recorded. Subsequently, an endobronchial blocker was inserted, and OLV was applied with a reduced VT of 5 mL/kg. Following a new set of measurements after 1 h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7 mL/kg) and CNEP (-15 cmH₂O) without any hyperinflation maneuver and data collection was then repeated at 5 min and 1 h. Compared to OLV, significant increases in PaO₂ (154.1 ± 13.3 vs. 173.8 ± 22.1) and decreases in PaCO₂ (52.6 ± 11.7 vs. 40.3 ± 4.5 mmHg, p < 0.05 for both) were observed 5 minutes following initiation of CNEP, and these benefits in gas exchange remained after an hour of CNEP. Gradual improvements in lung aeration in the non-collapsed lung were also detected by electrical impedance tomography (p < 0.05) after 5 and 60 min of CNEP. Hemodynamics and ventilation parameters remained stable under CNEP. Application of CNEP in the presence of whole lung atelectasis proved to be efficient in improving gas exchange via recruiting the lung without excessive airway pressures. These benefits of combined CNEP and positive pressure ventilation may have particular value in relieving atelectasis in the postoperative period of surgical procedures requiring OLV.

Association of preoperative spirometry tests with postoperative pulmonary complications after mediastinal mass resection: protocol for a retrospective cohort study

INTRODUCTION

Patients with a mediastinal mass are at risk of pulmonary complications in the perioperative period. Preoperative spirometry tests are recommended in patients scheduled for thoracic surgery. Our objective is to investigate the association between preoperative spirometry results and the incidence of postoperative pulmonary complications in patients following mediastinal mass resection, which may determine the usefulness of spirometry tests in the prediction of the perioperative respiratory risk.

METHODS AND ANALYSIS

This protocol describes a retrospective cohort study of patients with mediastinal masses in Shanghai Pulmonary Hospital between 1 September 2021 and 1 September 2022, with a planned sample size of 660 patients. The primary aim of this study is to explore the association between preoperative spirometry results and the occurrence of postoperative pulmonary complications after mediastinal mass resection. Logistic regression analysis will be used to calculate the adjusted incidence rate difference and incidence rate ratios (with 95% CIs).

ETHICS AND DISSEMINATION

The study was approved by the ethics committee of Shanghai Pulmonary Hospital (K21-372Y). The results of the study will be submitted to a peer-reviewed biomedical journal for publication and presented at relevant conferences.

Dolphin leukocytes exhibit an attenuated cytokine response and increase heme oxygenase activity upon exposure to lipopolysaccharides

Cetaceans exhibit physiological adaptations that allowed the transition to aquatic life, including a robust antioxidant defense system that prevents injury from repeated exposure to ischemia/reperfusion events associated with breath-hold diving. The signaling cascades that characterize ischemic inflammation in humans are well characterized. In contrast, cetaceans' molecular and biochemical mechanisms that confer tolerance to inflammatory events are poorly understood. Heme oxygenase (HO) is a cytoprotective protein with anti-inflammatory properties. HO catalyzes the first step in the oxidative degradation of heme. The inducible HO-1 isoform is regulated by various stimuli, including hypoxia, oxidant stress, and inflammatory cytokines. The objective of this study was to compare the response of HO-1 and cytokines to a proinflammatory challenge in leukocytes isolated from humans and bottlenose dolphins (Tursiops truncatus). We measured changes in HO activity and expression, and abundance and expression of interleukin 1 beta (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and heme oxygenase 1 (HMOX1) in leukocytes treated with lipopolysaccharide (LPS) for 24 and 48 h. HO activity increased (p < 0.05) in dolphin (48 h) but not human cells. TNF-α expression increased in human (24 h, 48 h), but not dolphin cells following LPS stimulation. LPS-induced cytokine expression was lower in dolphin than in human leukocytes, suggesting a blunted cytokine response in bottlenose dolphin leukocytes treated with LPS. Results suggest species-specific regulation of inflammatory cytokines in leukocytes treated with LPS, which may lead to differential responses to a pro-inflammatory challenge between marine and terrestrial mammals.

Dexmedetomidine improves lung compliance in patients undergoing lateral decubitus position of shoulder arthroscopy: A randomized controlled trial

BACKGROUND

The improvement of oxygenation and pulmonary mechanics in patients under general anesthesia can be achieved by dexmedetomidine (DEX) infusion. However, its role in patients undergoing lateral supine shoulder arthroscopy has not been thoroughly studied. This study aimed to evaluate the effect of DEX on lung compliance in patients undergoing shoulder arthroscopic surgery in a lateral decubitus position.

METHODS

The patients who underwent lateral recumbent shoulder arthroscopy under general anesthesia were randomly divided into the DEX group (group D) and the control group (group N). At the start of the trial, group D was given 0.5 μg/kg/hours continuous pumping until 30 minutes before the end of anesthesia; Group N was injected with normal saline at the same volume. The patients were recorded at each time point after intubation: supine position for 5 minutes (T0), lateral position for 5 minutes (T1), lateral position for 1 hour (T2), lateral position for 2 hours (T3), airway peak pressure, platform pressure, dynamic lung compliance, and static lung compliance, etc.

RESULTS

At the end of the drug infusion, the DEX group showed significant improved pulmonary mechanics and higher lung compliance than the control group. Compared with group N, group D's heart rate and mean arterial pressure were lower at all time points; there was no statistical difference in Tidal volume and Pressure end-tidal carbon dioxide data at each time point in Group D.

CONCLUSION

DEX can improve lung compliance and reduce airway pressure and platform pressure of patients undergoing shoulder arthroscopy in the lateral position under general anesthesia.

Combined Ultrasound-Guided Thoracic Paravertebral Nerve Block with Subcostal Transversus Abdominis Plane Block for Analgesia After Total Minimally Invasive Mckeown Esophagectomy: A Randomized, Controlled, and Prospective Study

INTRODUCTION

Thoracic paravertebral block (TPVB) and subcostal transverse abdominis plane block (TAP) have been considered to provide an effective analgesic effect for laparoscopic and thoracoscopic surgery, respectively. The purpose of this randomized, controlled, and prospective study was to evaluate the analgesic effect of TPVB combined with TAP in patients undergoing total minimally invasive Mckeown esophagectomy.

METHODS

Between February 2020 and December 2021, a total of 168 esophageal cancer patients undergoing McKeown esophagectomy at the Cancer Center of Sun Yat-Sen University, China, were randomly assigned to receive patient-controlled epidural analgesia alone (group PCEA, n = 56), patient-controlled intravenous analgesia alone (group PCIA, n = 56), and TPVB combined with TAP and patient-controlled intravenous analgesia (group PVB, n = 56). The primary outcome was a visual analogue scale (VAS) pain score on movement 48 h postoperatively. Secondary endpoints were pain scores at other points, intervention-related side effects, surgical complications, and length of intensive care unit and hospital stay. For the VAS pain score, the Kruskal-Wallis method was conducted for comparison of 3 treatment groups and further pairwise comparison with Bonferroni correction.

RESULTS

On movement, the VAS in the PVB group was higher than that in the PCEA group at 48 h, 72 h, 96 h, and 120 h postoperatively (p < 0.05) except in the postoperative anesthesia care unit (PACU) and 24 h postoperatively. The VAS in the PCIA group was higher than the PCEA and PVB groups in the first 4 days after surgery. The pulmonary complication rate in the PCIA group was significantly higher than the rate in the PCEA [95% Confidence Interval 0.214 (0.354, 0.067), p = 0.024].

CONCLUSIONS

Combined TPVB and TAP was more effective than intravenous opioid analgesia alone, while PCEA was more effective than TPVB combined with TAP and intravenous opioid analgesia for patients after McKeown esophagectomy.

TRIAL REGISTRATION

Chinese Clinical Trial Registry; ChiCTR2000029588.

[Consensus guideline on the interdisciplinary diagnosis of interstitial lung diseases]

The evaluation of a patient with interstitial lung disease (ILD) includes assessment of clinical, radiological, and often histopathological data. As there were no specific recommendations to guide the evaluation of patients under the suspicion of an ILD within the German practice landscape, this position statement from an interdisciplinary panel of ILD experts provides guidance related to the diagnostic modalities which should be used in the evaluation of ILD. This includes clinical assessment rheumatological evaluation, radiological examinations, histopathologic sampling and the need for a final discussion in a multidisciplinary team.

Benefit of Flow-Controlled Over Pressure-Regulated Volume Control Mode During One-Lung Ventilation: A Randomized Experimental Crossover Study

BACKGROUND

Application of a ventilation modality that ensures adequate gas exchange during one-lung ventilation (OLV) without inducing lung injury is of paramount importance. Due to its beneficial effects on respiratory mechanics and gas exchange, flow-controlled ventilation (FCV) may be considered as a protective alternative mode of traditional pressure- or volume-controlled ventilation during OLV. We investigated whether this new modality provides benefits compared with conventional ventilation modality for OLV.

METHODS

Ten pigs were anaesthetized and randomly assigned in a crossover design to be ventilated with FCV or pressure-regulated volume control (PRVC) ventilation. Arterial partial pressure of oxygen (Pa o2 ), carbon dioxide (Pa co2 ), ventilation and hemodynamical parameters, and lung aeration measured by electrical impedance tomography were assessed at baseline and 1 hour after the application of each modality during OLV using an endobronchial blocker.

RESULTS

Compared to PRVC, FCV resulted in increased Pa o2 (153.7 ± 12.7 vs 169.9 ± 15.0 mm Hg; P = .002) and decreased Pa co2 (53.0 ± 11.0 vs 43.2 ± 6.0 mm Hg; P < .001) during OLV, with lower respiratory elastance (103.7 ± 9.5 vs 77.2 ± 10.5 cm H 2 O/L; P < .001) and peak inspiratory pressure values (27.4 ± 1.9 vs 22.0 ± 2.3 cm H 2 O; P < .001). No differences in lung aeration or hemodynamics could be detected between the 2 ventilation modalities.

CONCLUSIONS

The application of FCV in OLV led to improvement in gas exchange and respiratory elastance with lower ventilatory pressures. Our findings suggest that FCV may offer an optimal, protective ventilation modality for OLV.

Emodin alleviates lung ischemia-reperfusion injury by suppressing gasdermin D-mediated pyroptosis in rats

BACKGROUND

Pyroptosis refers to programmed cell death associated with inflammation. Emodin has been reported to alleviate lung injuries caused by various pathological processes and attenuate ischemia-reperfusion (I/R) injuries in diverse tissues.

METHODS

Lewis rats were assigned into the sham, the I/R, and the I/R + emodin groups. Emodin and phosphate-buffered saline were intraperitoneally injected into rats of the emodin group and I/R group for 30 min, respectively. These rats were then subjected to left thoracotomy followed by 90-min clamping of the left hilum and 120-min reperfusion. Sham-operated rats underwent 210-min ventilation. Lung functions, histological changes, lung edema, and cytokine levels were assessed. Protein levels were measured by western blotting. Immunofluorescence staining was conducted to evaluate pyroptosis.

RESULTS

Emodin alleviated the I/R-induced lung dysfunction, lung damages, and inflammation. Protective effects of emodin against I/R-mediated endothelial pyroptosis was observed in vivo and in vitro. Mechanistically, emodin inactivated the TLR4/MyD88/NF-κB/NLRP3 pathway.

CONCLUSION

Emodin attenuates lung ischemia-reperfusion injury by inhibiting GSDMD-mediated pyroptosis in rats.

Surgical and perioperative management of flail chest with titanium plates: a French cohort series from a thoracic referral center

BACKGROUND

The development of titanium claw plates has made rib osteosynthesis easy to achieve and led to a renewed interest for this surgery. We report the management of patients referred to the intensive care unit (ICU) of a referral center for surgical rib fracture fixation (SRFF) after chest trauma.

METHODS

We performed a retrospective observational cohort study describing the patients' characteristics and analyzing the determinants of postoperative complications.

RESULTS

From November 2013 to December 2016, 42 patients were referred to our center for SRFF: 12 patients (29%) had acute respiratory failure, 6 of whom received invasive mechanical ventilation. The Thoracic Trauma Severity Score (TTSS) was 11.0 [9-12], with 7 [5-9] broken ribs and a flail chest in 92% of cases. A postoperative complication occurred in 18 patients (43%). Five patients developed ARDS (12%). Postoperative pneumonia occurred in 11 patients (26%). Two patients died in the ICU. In multivariable analysis, the Thoracic Trauma Severity Score (TTSS) (OR = 1.89; CI 95% 1.12-3.17; p = 0.016) and the Simplified Acute Physiology Score II without age (OR = 1.17; CI 95% 1.02-1.34; p = 0.024) were independently associated with the occurrence of a postoperative complication.

CONCLUSION

The TTSS score appears to be accurate for determining thoracic trauma severity. Short and long-term benefit of Surgical Rib Fracture Fixation should be assessed, particularly in non-mechanically ventilated patients.

Continuous Relationship of Operative Duration with Risk of Adverse Perioperative Outcomes and Early Discharge Undergoing Thoracoscopic Lung Cancer Surgery

Background: For thoracoscopic lung cancer surgery, the continuous relationship and the trigger point of operative duration with a risk of adverse perioperative outcomes (APOs) and early discharge remain unknown. Methods: This study enrolled 12,392 patients who underwent this surgical treatment. Five groups were stratified by operative duration: <60 min, 60−120 min, 120−180 min, 180−240 min, and ≥240 min. APOs included intraoperative hypoxemia, delayed extubation, postoperative pulmonary complications (PPCs), prolonged air leakage (PAL), postoperative atrial fibrillation (POAF), and transfusion. A restricted cubic spline (RCS) plot was used to characterize the continuous relationship of operative duration with the risk of APOs and early discharge. Results: The risks of the aforementioned APOs increased with each additional hour after the first hour. A J-shaped association with APOs was observed, with a higher risk in those with prolonged operative duration compared with those with shorter values. However, the probability of early discharge decreased from 0.465 to 0.350, 0.217, and 0.227 for each additional hour of operative duration compared with counterparts (<60 min), showing an inverse J-shaped association. The 90 min procedure appears to be a tipping point for a sharp increase in APOs and a significant reduction in early discharge. Conclusions: Our findings have important and meaningful implications for risk predictions and clinical interventions, and early rehabilitation, for APOs.

Pain in COVID-19: Quis est culpa?

<b>Background</b>: At present, during the coronavirus disease (COVID-19) pandemic, chronic pain is becoming more prominent, and it is also associated with the post-COVID-19 syndrome. Thanks to quick decisions on the therapy and as part of COVID-19 prevention, we have succeeded in stabilising the situation all over the world. On the other hand, ‘quick decisions’ have contributed to other significant issues which we are beginning to deal with now: in the effort to defeat the virus, many experts regarded the adverse effects of the medications used to be of secondary importance.<br /> <b>Purpose:</b> The article aims to demonstrate the side effects of treatment with various drugs (and their combinations) that are used to treat COVID-19 disease.<br /> <b>Method: </b>From the beginning of January until mid-May, the COVID-19 department of the 2nd Surgical Clinic of the Faculty of Medicine of the Comenius University in Bratislava (University Hospital Bratislava, Hospital of Saints Cyril and Methodius) treated 221 patients with moderate and severe course of COVID-19 (2nd wave of the pandemic). We saw some adverse effects and lack of effect of certain drugs for COVID-19.<br /> <b>Results: </b>The benefits of preventive measures compared to treatment are enormous. For example, corticoids can impair metabolism, cause diabetes, or suppress immunity. Antibiotics may cause colitis and blood pressure medications may negatively impact blood circulation.<br /> <b>Conclusion: </b>Preventive measures such as vaccination and activation of intrinsic antiviral immune systems are based on an incomparable benefit. Important in the process of the activation of antiviral immunity (linked to interferon synthesis) in the prevention of COVID-19 is the improvement of vitamin D deficit and the use of other micronutrients.<br /> <b>Practical value:</b> The results of the study will be valuable in the field of medicine, for virologists, pharmacologists, pharmacists, and medical professionals.

Endothelial glycocalyx in hepatopulmonary syndrome: An indispensable player mediating vascular changes

Hepatopulmonary syndrome (HPS) is a serious pulmonary vascular complication that causes respiratory insufficiency in patients with chronic liver diseases. HPS is characterized by two central pathogenic features-intrapulmonary vascular dilatation (IPVD) and angiogenesis. Endothelial glycocalyx (eGCX) is a gel-like layer covering the luminal surface of blood vessels which is involved in a variety of physiological and pathophysiological processes including controlling vascular tone and angiogenesis. In terms of lung disorders, it has been well established that eGCX contributes to dysregulated vascular contraction and impaired blood-gas barrier and fluid clearance, and thus might underlie the pathogenesis of HPS. Additionally, pharmacological interventions targeting eGCX are dramatically on the rise. In this review, we aim to elucidate the potential role of eGCX in IPVD and angiogenesis and describe the possible degradation-reconstitution equilibrium of eGCX during HPS through a highlight of recent literature. These studies strongly underscore the therapeutic rationale in targeting eGCX for the treatment of HPS.

Opioid-Free Anaesthesia Effectiveness in Thoracic Surgery-Objective Measurement with a Skin Conductance Algesimeter: A Randomized Controlled Trial

BACKGROUND

Chest surgery is associated with significant pain, and potent opioid medications are the primary medications used for pain relief. Opioid-free anaesthesia (OFA) combined with regional anaesthesia is promoted as an alternative in patients with an opioid contraindication.

METHODS

Objective: To assess the efficacy of OFA combined with a paravertebral block in pain treatment during video-assisted thoracic surgery.

DESIGN

A randomized, open-label study.

SETTING

A single university hospital between December 2015 and March 2018.

PARTICIPANTS

Sixty-six patients scheduled for elective video-assisted thoracic surgery were randomized into two groups. Of these, 16 were subsequently excluded from the analysis.

INTERVENTIONS

OFA combined with a paravertebral block with 0.5% bupivacaine in the OFA group; typical general anaesthesia with opioids in the control group.

MAIN OUTCOME MEASURES

Intraoperative nociceptive intensity measured with a skin conductance algesimeter (SCA) and traditional intraoperative monitoring.

RESULTS

Higher mean blood pressure was observed in the control group before induction and during intubation (p = 0.0189 and p = 0.0095). During chest opening and pleural drainage, higher SCA indications were obtained in the control group (p = 0.0036 and p = 0.0253), while in the OFA group, the SCA values were higher during intubation (p = 0.0325). SCA during surgery showed more stable values in the OFA group. Pearson analysis revealed a positive correlation between the SCA indications and mean blood pressure in both groups.

CONCLUSIONS

OFA combined with a paravertebral block provides effective nociception control during video-assisted thoracic surgery and can be an alternative for general anaesthesia with opioids. OFA provides a stable nociception response during general anaesthesia, as measured by SCA.

Effect of ventilation mode on postoperative pulmonary complications following lung resection surgery: a randomised controlled trial

The effect of intra-operative mechanical ventilation modes on pulmonary outcomes after thoracic surgery with one-lung ventilation has not been well established. We evaluated the impact of three common ventilation modes on postoperative pulmonary complications in patients undergoing lung resection surgery. In this two-centre randomised controlled trial, 1224 adults scheduled for lung resection surgery with one-lung ventilation were randomised to one of three groups: volume-controlled ventilation; pressure-controlled ventilation; and pressure-control with volume guaranteed ventilation. Enhanced recovery after surgery pathways and lung-protective ventilation protocols were implemented in all groups. The primary outcome was a composite of postoperative pulmonary complications within the first seven postoperative days. The outcome occurred in 270 (22%), with 87 (21%) in the volume control group, 89 (22%) in the pressure control group and 94 (23%) in the pressure-control with volume guaranteed group (p = 0.831). The secondary outcomes also did not differ across study groups. In patients undergoing lung resection surgery with one-lung ventilation, the choice of ventilation mode did not influence the risk of developing postoperative pulmonary complications. This is the first randomised controlled trial examining the effect of three ventilation modes on pulmonary outcomes in patients undergoing lung resection surgery.

Identifying biomarkers of ventilator induced lung injury during one-lung ventilation surgery: a scoping review

BACKGROUND

Ventilator-induced lung injury (VILI) can occur as a result of mechanical ventilation to two lungs. Thoracic surgery often requires one-lung ventilation (OLV). The potential for VILI is likely higher in OLV. The impact of OLV on development of post-operative pulmonary complications is not well understood. We aimed to perform a scoping review to determine reliable biomarkers of VILI after OLV.

METHODS

A scoping review was performed using Cochrane Collaboration methodology. We searched Medline, EMBASE and SCOPUS. Gray literature was searched. Studies of adult human or animal models without pre-existing lung damage exposed to OLV, with biomarker responses analyzed were included.

RESULTS

After screening 5,613 eligible papers, 89 papers were chosen for full text review, with 29 meeting inclusion. Approximately half (52%, n=15) of studies were conducted in humans in an intra-operative setting. Bronchoalveolar lavage (BAL) & serum analyses with enzyme-linked immunosorbent assay (ELISA)-based assays were most commonly used. The majority of analytes were investigated by a single study. Of the analytes that were investigated by two or more studies (n=31), only 16 were concordant in their findings. Across all sample types and studies 84% (n=66) of the 79 inflammatory markers and 75% (n=6) of the 8 anti-inflammatory markers tested were found to increase. Half (48%) of all studies showed an increase in TNF-α or IL-6.

CONCLUSIONS

A scoping review of the state of the evidence demonstrated that candidate biomarkers with the most evidence and greatest reliability are general markers of inflammation, such as IL-6 and TNF-α assessed using ELISA assays. Studies were limited in the number of biomarkers measured concurrently, sample size, and studies using human participants. In conclusion these identified markers can potentially serve as outcome measures for studies on OLV.

Interventions targeting postoperative pulmonary complications (PPCs) in patients undergoing esophageal cancer surgery: a systematic review of randomized clinical trials and narrative discussion

Postoperative pulmonary complications (PPCs) represent the most common complications after esophageal cancer surgery. The lack of a uniform reporting nomenclature and a severity classification has hampered consistency of research in this area, including the study of interventions targeting prevention and treatment of PPCs. This systematic review focused on RCTs of clinical interventions used to minimize the impact of PPCs. Searches were conducted up to 08/02/2021 on MEDLINE (OVID), CINAHL, Embase, Web of Science, and the COCHRANE library for RCTs and reported in accordance with PRISMA guidelines. A total of 339 citations, with a pooled dataset of 1,369 patients and 14 RCTs, were included. Heterogeneity of study design and outcomes prevented meta-analysis. PPCs are multi-faceted and not fully understood with respect to etiology. The review highlights the paucity of high-quality evidence for best practice in the management of PPCs. Further research in the area of intraoperative interventions and early postoperative ERAS standards is required. A consistent uniform for definition of pneumonia after esophagectomy and the development of a severity scale appears warranted to inform further RCTs and guidelines.

A structured narrative review of clinical and experimental studies of the use of different positive end-expiratory pressure levels during thoracic surgery

OBJECTIVES

This study aimed to present a review on the general effects of different positive end-expiratory pressure (PEEP) levels during thoracic surgery by qualitatively categorizing the effects into detrimental, beneficial, and inconclusive.

DATA SOURCE

Literature search of Pubmed, CNKI, and Wanfang was made to find relative articles about PEEP levels during thoracic surgery. We used the following keywords as one-lung ventilation, PEEP, and thoracic surgery.

RESULTS

We divide the non-individualized PEEP value into five grades, that is, less than 5, 5, 5-10, 10, and more than 10 cmH₂ O, among which 5 cmH₂ O is the most commonly used in clinic at present to maintain alveolar dilatation and reduce the shunt fraction and the occurrence of atelectasis, whereas individualized PEEP, adjusted by test titration or imaging method to adapt to patients' personal characteristics, can effectively ameliorate intraoperative oxygenation and obtain optimal pulmonary compliance and better indexes relating to respiratory mechanics.

CONCLUSIONS

Available data suggest that PEEP might play an important role in one-lung ventilation, the understanding of which will help in exploring a simple and economical method to set the appropriate PEEP level.

Regional pleural strain measurements during mechanical ventilation using ultrasound elastography: A randomized, crossover, proof of concept physiologic study

Background

Mechanical ventilation is a common therapy in operating rooms and intensive care units. When ill-adapted, it can lead to ventilator-induced lung injury (VILI), which is associated with poor outcomes. Excessive regional pulmonary strain is thought to be a major mechanism responsible for VILI. Scarce bedside methods exist to measure regional pulmonary strain. We propose a novel way to measure regional pleural strain using ultrasound elastography. The objective of this study was to assess the feasibility and reliability of pleural strain measurement by ultrasound elastography and to determine if elastography parameters would correlate with varying tidal volumes.

Methods

A single-blind randomized crossover proof of concept study was conducted July to October 2017 at a tertiary care referral center. Ten patients requiring general anesthesia for elective surgery were recruited. After induction, patients received tidal volumes of 6, 8, 10, and 12 mL.kg^–1 in random order, while pleural ultrasound cineloops were acquired at 4 standardized locations. Ultrasound radiofrequency speckle tracking allowed computing various pleural translation, strain and shear components. We screened 6 elastography parameters (lateral translation, lateral absolute translation, lateral strain, lateral absolute strain, lateral absolute shear and Von Mises Strain) to identify those with the best dose-response with tidal volumes using linear mixed effect models. Goodness-of-fit was assessed by the coefficient of determination. Intraobserver, interobserver and test-retest reliability were calculated using intraclass correlation coefficients.

Results

Analysis was possible in 90.7% of ultrasound cineloops. Lateral absolute shear, lateral absolute strain and Von Mises strain varied significantly with tidal volume and offered the best dose-responses and data modeling fits. Point estimates for intraobserver reliability measures were excellent for all 3 parameters (0.94, 0.94, and 0.93, respectively). Point estimates for interobserver (0.84, 0.83, and 0.77, respectively) and test-retest (0.85, 0.82, and 0.76, respectively) reliability measures were good.

Conclusion

Strain imaging is feasible and reproducible. Future studies will have to investigate the clinical relevance of this novel imaging modality.

Clinical trial registration

www.Clinicaltrials.gov, identifier NCT03092557.