Does a protective ventilation strategy reduce the risk of pulmonary complications after lung cancer surgery?: a randomized controlled trial

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

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.

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

OBJECTIVES

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

DESIGN

Multicenter, randomized, single-blind, controlled trial.

SETTING

Sixteen Italian hospitals.

PARTICIPANTS

A total of 880 patients undergoing elective major lung resection.

INTERVENTIONS

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

MEASUREMENTS AND MAIN RESULTS

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

CONCLUSIONS

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

Impact of Lower Tidal Volumes During One-Lung Ventilation: A 2022 Update of the Meta-analysis of Randomized Controlled Trials

OBJECTIVES

To clarify the influence of lower tidal volume (4-7 mL/kg) compared with higher tidal volume (8-15 mL/kg) during one-lung ventilation (OLV) on gas exchange and postoperative clinical outcome.

DESIGN

Meta-analysis of randomized trials.

SETTING

Thoracic surgery.

PARTICIPANTS

Patients receiving OLV.

INTERVENTIONS

Lower tidal volume during OLV.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was PaO2-to-the oxygen fraction (PaO2/FIO2) ratio at the end of the surgery, after the reinstitution of two-lung ventilation. Secondary endpoints included perioperative changes in PaO2/FIO2 ratio and carbon dioxide (PaCO2) tension, airway pressure, the incidence of postoperative pulmonary complications, arrhythmia, and length of hospital stay. Seventeen randomized controlled trials (1,463 patients) were selected. Overall analysis showed that the use of low tidal volume during OLV was associated with a significantly higher PaO2/FIO2 ratio 15 minutes after the start of OLV and at the end of surgery (mean difference 33.7 mmHg [p = 0.02] and mean difference 18.59 mmHg [p < 0.001], respectively). The low tidal volume also was associated with higher PaCO2 values 15 minutes and 60 minutes after the start of OLV and with lower airway pressure, which was maintained during two-lung ventilation after surgery. Moreover, the application of lower tidal volume was associated with fewer postoperative pulmonary complications (odds ratio 0.50; p < 0.001) and arrhythmias (odds ratio 0.58; p = 0.009), with no difference in length of hospital stay.

CONCLUSIONS

The use of lower tidal volume, a component of protective OLV, increases the PaO2/FIO2 ratio, reduces the incidence of postoperative pulmonary complications, and should be considered strongly in daily practice.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

Whole-lung finite-element models for mechanical ventilation and respiratory research applications

Mechanical ventilation has been a vital treatment for Covid-19 patients with respiratory failure. Lungs assisted with mechanical ventilators present a wide variability in their response that strongly depends on air-tissue interactions, which motivates the creation of simulation tools to enhance the design of ventilatory protocols. In this work, we aim to create anatomical computational models of the lungs that predict clinically-relevant respiratory variables. To this end, we formulate a continuum poromechanical framework that seamlessly accounts for the air-tissue interaction in the lung parenchyma. Based on this formulation, we construct anatomical finite-element models of the human lungs from computed-tomography images. We simulate the 3D response of lungs connected to mechanical ventilation, from which we recover physiological parameters of high clinical relevance. In particular, we provide a framework to estimate respiratory-system compliance and resistance from continuum lung dynamic simulations. We further study our computational framework in the simulation of the supersyringe method to construct pressure-volume curves. In addition, we run these simulations using several state-of-the-art lung tissue models to understand how the choice of constitutive models impacts the whole-organ mechanical response. We show that the proposed lung model predicts physiological variables, such as airway pressure, flow and volume, that capture many distinctive features observed in mechanical ventilation and the supersyringe method. We further conclude that some constitutive lung tissue models may not adequately capture the physiological behavior of lungs, as measured in terms of lung respiratory-system compliance. Our findings constitute a proof of concept that finite-element poromechanical models of the lungs can be predictive of clinically-relevant variables in respiratory medicine.

Ventilation during Lung Resection and Critical Care: Comparative Clinical Outcomes

Recent evidence suggests that outcomes do not meaningfully differ between thoracic surgery patients who are ventilated with a low or higher tidal volume and the effects of low versus higher positive end-expiratory pressure are unclear.

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.

Effects of enhanced recovery after surgery plus pulmonary rehabilitation on complications after video-assisted lung cancer surgery: a multicentre randomised controlled trial

BACKGROUND

Lung cancer surgery is associated with a high incidence of postoperative pulmonary complications (PPCs). We evaluated whether enhanced recovery after surgery plus pulmonary rehabilitation was superior over enhanced recovery after surgery alone in reducing the incidence of postoperative PPCs and length of hospital stay.

METHODS

In this pragmatic multicentre, randomised controlled, parallel-group clinical trial, eligible patients scheduled for video-assisted lung cancer surgery were randomly assigned (1:1) to either a newly developed programme that integrated preoperative and postoperative pulmonary rehabilitation components into a generic thoracic enhanced recovery after surgery pathway, or routine thoracic enhanced recovery after surgery. Primary outcome was the overall occurrence of PPCs within 2 weeks after surgery. Secondary outcomes were the occurrence of specific complications, time to removal of chest drain, and length of hospital stay (LOS).

RESULTS

Of 428 patients scheduled for lung cancer surgery, 374 were randomised with 187 allocated to the experimental programme and 187 to control. Incidence of PPCs at 14 Days was 18.7% (35/187) in the experimental group and 33.2% (62/187) in the control group (intention-to-treat, unadjusted HR 0.524, 95% CI 0.347 to 0.792, p=0.002). Particularly, significant risk reduction was observed regarding pleural effusion, pneumonia and atelectasis. Time to removal of chest drain and LOS were not significantly reduced in the experimental group.

CONCLUSIONS

Adding pulmonary rehabilitation to enhanced recovery after surgery appears to be effective in reducing the incidence of PPCs, but not LOS. Standard integration of pulmonary rehabilitation into thoracic enhanced recovery after surgery is a promising approach to PPC prophylaxis.

TRIAL REGISTRATION NUMBER

ChiCTR1900024646.

Effect of Driving Pressure-Oriented Ventilation on Patients Undergoing One-Lung Ventilation During Thoracic Surgery: A Systematic Review and Meta-Analysis

Background

Hypoxemia and fluctuations in respiratory mechanics parameters are common during one-lung ventilation (OLV) in thoracic surgery. Additionally, the incidence of postoperative pulmonary complications (PPC_S) in thoracic surgery is higher than that in other surgeries. Previous studies have demonstrated that driving pressure-oriented ventilation can reduce both mortality in patients with acute respiratory distress syndrome (ARDS) and the incidence of PPC_S in patients undergoing general anesthesia. Our aim was to determine whether driving pressure-oriented ventilation improves intraoperative physiology and outcomes in patients undergoing thoracic surgery.

Methods

We searched MEDLINE via PubMed, Embase, Cochrane, Web of Science, and ClinicalTrials.gov and performed a meta-analysis to compare the effects of driving pressure-oriented ventilation with other ventilation strategies on patients undergoing OLV. The primary outcome was the PaO₂/FiO₂ ratio (P/F ratio) during OLV. The secondary outcomes were the incidence of PPC_S during follow-up, compliance of the respiratory system during OLV, and mean arterial pressure during OLV.

Results

This review included seven studies, with a total of 640 patients. The PaO₂/FiO₂ ratio was higher during OLV in the driving pressure-oriented ventilation group (mean difference [MD]: 44.96; 95% confidence interval [CI], 24.22–65.70.32; I²: 58%; P < 0.0001). The incidence of PPC_S was lower (OR: 0.58; 95% CI, 0.34–0.99; I²: 0%; P = 0.04) and the compliance of the respiratory system was higher (MD: 6.15; 95% CI, 3.97–8.32; I²: 57%; P < 0.00001) in the driving pressure-oriented group during OLV. We did not find a significant difference in the mean arterial pressure between the two groups.

Conclusion

Driving pressure-oriented ventilation during OLV in patients undergoing thoracic surgery was associated with better perioperative oxygenation, fewer PPC_S, and improved compliance of the respiratory system.

Systematic Review Registration

PROSPERO, identifier: CRD42021297063.

Recommendations of the Society of Thoracic Surgery and the Section of Cardiothoracic and Vascular Surgery of the Spanish Society of Anesthesia, Resuscitation and Pain Therapy, for patients undergoing lung surgery included in an intensified recovery program

In recent years, multidisciplinary programs have been implemented that include different actions during the pre, intra and postoperative period, aimed at reducing perioperative stress and therefore improving the results of patients undergoing surgical interventions. Initially, these programs were developed for colorectal surgery and from there they have been extended to other surgeries. Thoracic surgery, considered highly complex, like other surgeries with a high postoperative morbidity and mortality rate, may be one of the specialties that most benefit from the implementation of these programs. This review presents the recommendations made by different specialties involved in the perioperative care of patients who require resection of a lung tumor. Meta-analyzes, systematic reviews, randomized and non-randomized controlled studies, and retrospective studies conducted in patients undergoing this type of intervention have been taken into account in preparing the recommendations presented in this guide. The GRADE scale has been used to classify the recommendations, assessing on the one hand the level of evidence published on each specific aspect and, on the other hand, the strength of the recommendation with which the authors propose its application. The recommendations considered most important for this type of surgery are those that refer to pre-habilitation, minimization of surgical aggression, excellence in the management of perioperative pain and postoperative care aimed at providing rapid postoperative rehabilitation.

Effect of pressure controlled volume guaranteed ventilation during pulmonary resection in children

The purpose of the study was to evaluate the effect of pressure controlled volume guaranteed ventilation in children requiring one lung ventilation during pulmonary resection. Patients were randomly assigned to the lung protective ventilation combined with pressure controlled volume guaranteed group (PCV-VG group) or the lung protective ventilation combined with volume controlled ventilation group (VCV group). Both groups received tidal-volume ventilation of 8 ml kg⁻¹ body weight during two lung ventilation and 6 ml kg⁻¹ during OLV, with sustained 5 cmH₂O positive end-expiratory pressure. Data collections were mainly performed at 10 min after induction of anaesthesia during TLV (T1), 5 min after OLV initiation (T2) and 5 min after complete CO2 insufflations (T3). In total, 63 patients were randomly assigned to the VCV (n = 31) and PCV-VG (n = 32) groups. The PCV-VG group exhibited lower PIP than the VCV group at T1 (16.8 ± 2.3 vs. 18.7 ± 2.7 cmH₂O, P = 0.001), T2 (20.2 ± 2.7 vs. 22.4 ± 3.3 cmH₂O, P = 0.001), and T3 (23.8 ± 3.2 vs. 26.36 ± 3.7 cmH₂O, P = 0.01). Static compliance was higher in the PCV-VG group at T1, T2, and T3 (P = 0.01). After anaesthesia induction, lung aeration deteriorated, but with no immediate postoperative difference in both groups. Postoperative lung aeration improved and returned to normal from 2.5 h postextubation in both groups. PH was lower and PaCO₂ was higher in VCV group than PCV-VG group during one lung ventilation. No differences were observed in PaO₂-FiO₂-ratio at T2 and T3, the incidence of postoperative pulmonary complications, intraoperative desaturation and the length of hospital stay. In paediatric patients, who underwent pulmonary resection requiring one lung ventilation, PCV-VG was superior to VCV in its ability to provide lower PIP, higher static compliance and lower PaCO₂ at one lung ventilation during pneumothorax. However, its beneficial effects on different pathological situations in pediatric patients need more investigation.

A randomised controlled trial on roles of prostaglandin E1 nebulization among patients undergoing one lung ventilation

Background

Prostaglandin E1 (PGE1) has been reported to maintain adequate oxygenation among patients under 60% FiO₂ one-lung ventilation (OLV). This research aimed to explore whether PGE1 is safe in pulmonary shunt and oxygenation under 40% FiO₂ OLV and provide a reference concentration of PGE1.

Methods

Totally 90 esophageal cancer patients treated with thoracotomy were enrolled in this study, randomly divided into three groups (n = 30/group): Group A (60% FiO₂ and 0.1 µg/kg PGE1), Group B (40% FiO₂ and 0.1 µg/kg PGE1), and Group C (40% FiO₂, 0.2 µg/kg PGE1). Primary outcomes were oxygenation and pulmonary shunt during OLV. Secondary outcomes included oxidative stress after OLV.

Results

During OLV, patients in Group C and B had lower levels of PaO₂, SaO₂, SpO₂, MAP, and Qs/Qt than those in Group A (P < 0.05). At T2 (OLV 10 min), patients in Group C and B exhibited a lower level of PaO₂/FiO₂ than those in Group A, without any statistical difference at other time points. The IL-6 levels of patients in different groups were different at T8 (F = 3.431, P = 0.038), with IL-6 in Group C being lower than that in Group B and A. MDA levels among the three groups differed at T5 (F = 4.692, P = 0.012) and T7 (F = 5.906, P = 0.004), with the MDA level of Group C being lower than that of Group B and A at T5, and the MDA level of Group C and B being lower than that of Group A at T7. In terms of TNF-α level, patients in Group C had a lower level than those in Group B and A at T8 (F = 3.598, P = 0.033). Compared with patients who did not use PGE1, patients in Group C had comparable complications and lung infection scores.

Conclusion

The concentration of FiO₂ could be reduced from 60 to 40% to maintain oxygenation. 40% FiO₂ + 0.2 µg/kg PGE1 is recommended as a better combination on account of its effects on the inflammatory factors.

Trial registration: Chictr.org.cn identifier: ChiCTR1800018288, 09/09/2018.

Hypoxemia in Young Children Undergoing One-lung Ventilation: A Retrospective Cohort Study

BACKGROUND

One-lung ventilation in children remains a specialized practice with low case numbers even at tertiary centers, preventing an assessment of best practices. The authors hypothesized that certain case factors may be associated with a higher risk of intraprocedural hypoxemia in children undergoing thoracic surgery and one-lung ventilation.

METHODS

The Multicenter Perioperative Outcomes database and a local quality improvement database were queried for documentation of one-lung ventilation in children 2 months to 3 yr of age inclusive between 2010 and 2020. Patients undergoing vascular or other cardiac procedures were excluded. All records were reviewed electronically for the presence of hypoxemia, oxygen saturation measured by pulse oximetry (Spo2) less than 90% for 3 min or more continuously, and severe hypoxemia, Spo2 less than 90% for 5 min or more continuously during one-lung ventilation. Records were also assessed for hypercarbia, end-tidal CO2 greater than 60 mmHg for 5 min or more or a Paco2 greater than 60 on arterial blood gas. Covariates assessed for association with these outcomes included age, weight, American Society of Anesthesiologists (Schaumburg, Illinois) Physical Status 3 or greater, duration of one-lung ventilation, preoperative Spo2 less than 98%, bronchial blocker versus endobronchial intubation, left operative side, video-assisted thoracoscopic surgery, lower tidal volume ventilation (tidal volume less than or equal to 6 ml/kg plus positive end expiratory pressure greater than or equal to 4 cm H2O for more than 80% of the duration of one-lung ventilation), and type of procedure.

RESULTS

Three hundred six cases from 15 institutions were included for analysis. Hypoxemia and severe hypoxemia occurred in 81 of 306 (26%) patients and 56 of 306 (18%), respectively. Hypercarbia occurred in 153 of 306 (50%). Factors associated with lower risk of hypoxemia in multivariable analysis included left operative side (odds ratio, 0.45 [95% CI, 0.251 to 0.78]) and bronchial blocker use (odds ratio, 0.351 [95% CI, 0.177 to 0.67]). Additionally, use of a bronchial blocker was associated with a reduced risk of severe hypoxemia (odds ratio, 0.290 [95% CI, 0.125 to 0.62]).

CONCLUSIONS

Use of a bronchial blocker was associated with a lower risk of hypoxemia in young children undergoing one-lung ventilation.

EDITOR’S PERSPECTIVE

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

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

Recommendations of the Society of Thoracic Surgery and the Section of Cardiothoracic and Vascular Surgery of the Spanish Society of Anesthesia, Resuscitation and Pain Therapy, for patients undergoing lung surgery included in an intensified recovery program

In recent years, multidisciplinary programs have been implemented that include different actions during the pre, intra and postoperative period, aimed at reducing perioperative stress and therefore improving the results of patients undergoing surgical interventions. Initially, these programs were developed for colorectal surgery and from there they have been extended to other surgeries. Thoracic surgery, considered highly complex, like other surgeries with a high postoperative morbidity and mortality rate, may be one of the specialties that most benefit from the implementation of these programs. This review presents the recommendations made by different specialties involved in the perioperative care of patients who require resection of a lung tumor. Meta-analyses, systematic reviews, randomized and non-randomized controlled studies, and retrospective studies conducted in patients undergoing this type of intervention have been taken into account in preparing the recommendations presented in this guide. The GRADE scale has been used to classify the recommendations, assessing on the one hand the level of evidence published on each specific aspect and, on the other hand, the strength of the recommendation with which the authors propose its application. The recommendations considered most important for this type of surgery are those that refer to pre-habilitation, minimization of surgical aggression, excellence in the management of perioperative pain and postoperative care aimed at providing rapid postoperative rehabilitation.

Individualized positive end-expiratory pressure (PEEP) during one-lung ventilation for prevention of postoperative pulmonary complications in patients undergoing thoracic surgery: A meta-analysis

BACKGROUND

Positive end-expiratory pressure (PEEP) is an important part of the lung protection strategies for one-lung ventilation (OLV). However, a fixed PEEP value is not suitable for all patients. Our objective was to determine the prevention of individualized PEEP on postoperative complications in patients undergoing one-lung ventilation.

METHOD

We searched the PubMed, Embase, and Cochrane and performed a meta-analysis to compare the effect of individual PEEP vs fixed PEEP during single lung ventilation on postoperative pulmonary complications. Our primary outcome was the occurrence of postoperative pulmonary complications during follow-up. Secondary outcomes included the partial pressure of arterial oxygen and oxygenation index during one-lung ventilation.

RESULT

Eight studies examining 849 patients were included in this review. The rate of postoperative pulmonary complications was reduced in the individualized PEEP group with a risk ratio of 0.52 (95% CI:0.37-0.73; P = .0001). The partial pressure of arterial oxygen during the OLV in the individualized PEEP group was higher with a mean difference 34.20 mm Hg (95% CI: 8.92-59.48; P = .0004). Similarly, the individualized PEEP group had a higher oxygenation index, MD: 49.07mmHg, (95% CI: 27.21-70.92; P < .0001).

CONCLUSIONS

Individualized PEEP setting during one-lung ventilation in patients undergoing thoracic surgery was associated with fewer postoperative pulmonary complications and better perioperative oxygenation.

Comparison of the effects of 2 ventilatory strategies using tidal volumes of 6 and 8 ml/kg on pulmonary shunt and alveolar dead space volume in upper abdominal cancers surgery

Background: High tidal volume leads to inflammation, and low tidal volume leads to atelectasia and hypoxemia. This study was conducted to compare the effect of 6 mL/kg with positive end-expiratory pressure (PEEP) and 8 mL/kg without PEEP on pulmonary shunt and dead space volume.

Methods: This clinical trial was done on 36 patients aged 20 to 65 years old with ASA I-II. They were candidates for upper abdominal surgery and divided randomly into 2 groups. One group were ventilated with the tidal volume = 8 mL/kg without PEEP (TV8). The other group received the tidal volume = 6 mL/kg with low PEEP = 5 cm H2O (TV6). Arterial and central venous blood gases were taken after intubation and 2 hours later. Additionally, the vital signs of the patients were checked every 30 minutes. Data analysis was performed using t test, chi-square test, and repeated measures analysis of variance with SPSS software, version 16 (SPSS Inc). P value less than.05 were meaningful.

Results: There was no significant difference on the preanesthesia parameters. The pulmonary shunt was 13.5±0.1% and 18.6±0.2% in the groups TV6 and TV8, respectively (p=0.132), which slightly decreased after 2 hours in both groups without any significant difference (p=0.284). Prior to the ventilation, the ratios of dead space to tidal volume were 0.25±0.2 and 0.14±0.1 in the TV6 and TV8 groups, respectively (p=0.163), and after 2 hours, they were 0.23±0.11 and 0.16±0.1 in the TV6 and TV8 groups, respectively (p=0.271). There was no significant difference between the groups for blood pressure and peripheral and arterial oxygenation changes.

Conclusion: The tidal volume of 6 mL/kg with the PEEP of 5 mmHg was similar to the tidal volume of 8 mL/kg without PEEP for hemodynamic and pulmonary changes (oxygenation, shunt, and dead space).

[Intraoperative Ventilation Approaches to One-lung Ventilation]

The management of thoracic surgery patients is challenging to the anesthetist, since one-lung ventilation (OLV) includes at least two major conditions: sufficient oxygenation and lung protection. The first is mainly because the ventilation of one lung is stopped while perfusion to that lung continues; the latter is related to the fact that the whole ventilation is applied to only a single lung. Recommendations for maintaining the oxygenation and methods of lung protection may contradict each other (e. g. high vs. low inspiratory oxygen fraction (FiO₂), high vs. low tidal volume, etc.). Therefore, a high degree of pathophysiological understanding and manual skills are required in the management of these patients.In light of recent clinical studies, this review focuses on a current protective strategy for OLV, which includes a possible decrease in FiO₂, lowered V_T, the application of positive end-expiratory pressure (PEEP) to the dependent and continuous positive airway pressure (CPAP) to the non-dependent lung and alveolar recruitment manoeuvres as well. Other approaches such as the choice of anaesthetics, remote ischemic preconditioning, fluid management and pain therapy can support the success of ventilatory strategy. The present work describes new developments that may change the classical approach in this respect.

A Lower Tidal Volume Regimen during One-lung Ventilation for Lung Resection Surgery Is Not Associated with Reduced Postoperative Pulmonary Complications

BACKGROUND

Protective ventilation may improve outcomes after major surgery. However, in the context of one-lung ventilation, such a strategy is incompletely defined. The authors hypothesized that a putative one-lung protective ventilation regimen would be independently associated with decreased odds of pulmonary complications after thoracic surgery.

METHODS

The authors merged Society of Thoracic Surgeons Database and Multicenter Perioperative Outcomes Group intraoperative data for lung resection procedures using one-lung ventilation across five institutions from 2012 to 2016. They defined one-lung protective ventilation as the combination of both median tidal volume 5 ml/kg or lower predicted body weight and positive end-expiratory pressure 5 cm H2O or greater. The primary outcome was a composite of 30-day major postoperative pulmonary complications.

RESULTS

A total of 3,232 cases were available for analysis. Tidal volumes decreased modestly during the study period (6.7 to 6.0 ml/kg; P < 0.001), and positive end-expiratory pressure increased from 4 to 5 cm H2O (P < 0.001). Despite increasing adoption of a "protective ventilation" strategy (5.7% in 2012 vs. 17.9% in 2016), the prevalence of pulmonary complications did not change significantly (11.4 to 15.7%; P = 0.147). In a propensity score matched cohort (381 matched pairs), protective ventilation (mean tidal volume 6.4 vs. 4.4 ml/kg) was not associated with a reduction in pulmonary complications (adjusted odds ratio, 0.86; 95% CI, 0.56 to 1.32). In an unmatched cohort, the authors were unable to define a specific alternative combination of positive end-expiratory pressure and tidal volume that was associated with decreased risk of pulmonary complications.

CONCLUSIONS

In this multicenter retrospective observational analysis of patients undergoing one-lung ventilation during thoracic surgery, the authors did not detect an independent association between a low tidal volume lung-protective ventilation regimen and a composite of postoperative pulmonary complications.

EDITOR’S PERSPECTIVE

Guidelines on enhanced recovery after pulmonary lobectomy

OBJECTIVE

To establish recommendations for optimisation of the management of patients undergoing pulmonary lobectomy, particularly Enhanced Recovery After Surgery (ERAS).

DESIGN

A consensus committee of 13 experts from the French Society of Anaesthesia and Intensive Care Medicine (Soci,t, franOaise d'anesth,sie et de r,animation, SFAR) and the French Society of Thoracic and Cardiovascular Surgery (Soci,t, franOaise de chirurgie thoracique et cardiovasculaire, SFCTCV) was convened. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industry funding. The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence.

METHODS

Five domains were defined: 1) patient pathway and patient information; 2) preoperative management and rehabilitation; 3) anaesthesia and analgesia for lobectomy; 4) surgical strategy for lobectomy; and 5) enhanced recovery after surgery. For each domain, the objective of the recommendations was to address a number of questions formulated according to the PICO model (Population, Intervention, Comparison, Outcome). An extensive literature search on these questions was carried out and analysed using the GRADE® methodology. Recommendations were formulated according to the GRADE® methodology, and were then voted by all experts according to the GRADE grid method.

RESULTS

The SFAR/SFCTCV guideline panel provided 32 recommendations on the management of patients undergoing pulmonary lobectomy. After two voting rounds and several amendments, a strong consensus was reached for 31 of the 32 recommendations and a moderate consensus was reached for the last recommendation. Seven of these recommendations present a high level of evidence (GRADE 1+), 23 have a moderate level of evidence (18 GRADE 2+ and 5 GRADE 2-), and 2 correspond to expert opinions. Finally, no recommendation was provided for 2 of the questions.

CONCLUSIONS

A strong consensus was expressed by the experts to provide recommendations to optimise the whole perioperative management of patients undergoing pulmonary lobectomy.

Minimizing postoperative pulmonary complications in thoracic surgery patients

PURPOSE OF REVIEW

Quantification and optimization of perioperative risk factors focusing on anesthesia-related strategies to reduce postoperative pulmonary complications (PPCs) after lung and esophageal surgery.

RECENT FINDINGS

There is an increasing amount of multimorbid patients undergoing thoracic surgery due to the demographic development and medical progress in perioperative medicine. Nevertheless, the rate of PPCs after thoracic surgery is still up to 30-50% with a significant influence on patients' outcome. PPCs are ranked first among the leading causes of early mortality after thoracic surgery. Although patients' risk factors are usually barely modifiable, current research focuses on procedural risk factors. From the surgical position, the minimal-invasive approach using video-assisted thoracoscopy and laparoscopy leads to a decreased rate of PPCs. The anesthesiological strategy to reduce the incidence of PPCs after thoracic surgery includes neuroaxial anesthesia, lung-protective ventilation, and goal-directed hemodynamic therapy.

SUMMARY

The main anesthesiological strategies to reduce PPCs after thoracic surgery include the use of epidural anesthesia, lung-protective ventilation: PEEP (positive end-expiratory pressure) of 5-8 mbar, tidal volume of 5 ml/kg BW (body weight) and goal-directed hemodynamics: CI (cardiac index) ≥ 2.5 l/min per m2, MAD (Mean arterial pressure) ≥ 70 mmHg, SVV (stroke volume variation) < 10% with a total amount of perioperative crystalloid fluids ≤ 6 ml/kg BW (body weight) per hour.

Tidal volume during 1-lung ventilation: A systematic review and meta-analysis

BACKGROUND

The selection of tidal volumes for 1-lung ventilation remains unclear, because there exists a trade-off between oxygenation and risk of lung injury. We conducted a systematic review and meta-analysis to determine how oxygenation, compliance, and clinical outcomes are affected by tidal volume during 1-lung ventilation.

METHODS

A systematic search of MEDLINE and EMBASE was performed. A systematic review and random-effects meta-analysis was conducted. Pooled mean difference estimated arterial oxygen tension, compliance, and length of stay; pooled odds ratio was calculated for composite postoperative pulmonary complications. Risk of bias was determined using the Cochrane risk of bias and Newcastle-Ottawa tools.

RESULTS

Eighteen studies were identified, comprising 3693 total patients. Low tidal volumes (5.6 [±0.9] mL/kg) were not associated with significant differences in partial pressure of oxygen (-15.64 [-88.53-57.26] mm Hg; P = .67), arterial oxygen tension to fractional intake of oxygen ratio (14.71 [-7.83-37.24]; P = .20), or compliance (2.03 [-5.22-9.27] mL/cmH2O; P = .58) versus conventional tidal volume ventilation (8.1 [±3.1] mL/kg). Low versus conventional tidal volume ventilation had no significant impact on hospital length of stay (-0.42 [-1.60-0.77] days; P = .49). Low tidal volumes are associated with significantly decreased odds of pulmonary complications (pooled odds ratio, 0.40 [0.29-0.57]; P < .0001).

CONCLUSIONS

Low tidal volumes during 1-lung ventilation do not worsen oxygenation or compliance. A low tidal volume ventilation strategy during 1-lung ventilation was associated with a significant reduction in postoperative pulmonary complications.

Recommendations from the Italian intersociety consensus on Perioperative Anesthesa Care in Thoracic surgery (PACTS) part 2: intraoperative and postoperative care

Introduction

Anesthetic care in patients undergoing thoracic surgery presents specific challenges that require a multidisciplinary approach to management. There remains a need for standardized, evidence-based, continuously updated guidelines for perioperative care in these patients.

Methods

A multidisciplinary expert group, the Perioperative Anesthesia in Thoracic Surgery (PACTS) group, was established to develop recommendations for anesthesia practice in patients undergoing elective lung resection for lung cancer. The project addressed three key areas: preoperative patient assessment and preparation, intraoperative management (surgical and anesthesiologic care), and postoperative care and discharge. A series of clinical questions was developed, and literature searches were performed to inform discussions around these areas, leading to the development of 69 recommendations. The quality of evidence and strength of recommendations were graded using the United States Preventive Services Task Force criteria.

Results

Recommendations for intraoperative care focus on airway management, and monitoring of vital signs, hemodynamics, blood gases, neuromuscular blockade, and depth of anesthesia. Recommendations for postoperative care focus on the provision of multimodal analgesia, intensive care unit (ICU) care, and specific measures such as chest drainage, mobilization, noninvasive ventilation, and atrial fibrillation prophylaxis.

Conclusions

These recommendations should help clinicians to improve intraoperative and postoperative management, and thereby achieve better postoperative outcomes in thoracic surgery patients. Further refinement of the recommendations can be anticipated as the literature continues to evolve.

Management of Tracheoesophageal Fistula Repair With Cardiac Dextroposition and Right Lung Agenesis: A Case Report

Tracheoesophageal fistulae (TEF) commonly occur as part of the vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal, and limb abnormalities (VACTERL) association. However, pulmonary agenesis is not typically seen with TEF. We report the anesthetic management of a TEF repair in a 33-week-old, 1.6-kg, monochorionic diamniotic twin with right lung agenesis, intrauterine growth restriction, and cardiac dextroposition. Due to the unique position of the heart, the patient periodically lost complete cardiac output during the exposure and repair of the esophagus.

Intraoperative Anesthetic Management of the Thoracic Patient

The intraoperative anesthetic management for thoracic surgery can impact a patient's postoperative course, especially in patients with significant lung disease. One-lung ventilation poses an inherent risk to patients, including hypoxemia, acute lung injury, and right ventricular dysfunction. Patient-specific ventilator management strategies during one-lung ventilation can reduce postoperative morbidity.

Effects of prostaglandin E1 nebulization of ventilated lung under 60%O2 one lung ventilation on patients' oxygenation and oxidative stress: a randomised controlled trial

Background

High FiO₂ during one-lung ventilation (OLV) can improve oxygenation, but increase the risk of atelectasis and oxidative stress. The aim of this study was to analyze whether Prostaglandin E₁ (PGE₁) can improve oxygenation and attenuate oxidative stress during OLV under a lower FiO₂.

Method

Ninety patients selectively undergoing thoracotomy for esophageal cancer were randomly divided into three groups (n = 30/group): Group P (FiO₂ = 0.6, inhaling PGE₁ 0.1 μg/kg), Group L (FiO₂ = 0.6) and Group C (FiO₂ = 1.0). The primary outcomes were oxygenation and pulmonary shunt during OLV. Secondary outcomes included haemodynamics, respiratory mechanics and oxidative stress in serum.

Results

Patients in Group P had significantly higher PaO₂ and lower shunt fraction in 30 min of OLV compared with Group L. Compared with Group C, patients in Group P had similar levels of PaO₂/FiO₂ in 60 min and higher levels of PaO₂/FiO₂ at 2 h during OLV. The levels of PvO₂ and SvO₂ in Group P and Group L were significantly lower than Group C. Patients in Group P and Group L had significantly higher levels of superoxide dismutase and lower levels of malondialdehyde than Group C. No significant differences were found in SPO₂, ETCO₂, PaCO₂, Paw, HR and MAP among the three groups. The complications in Group C were significantly higher than another two groups.

Conclusion

PGE₁ can maintain adequate oxygenation in patients with low FiO₂ (0.6) during OLV. Reducing FiO₂ to 0.6 during OLV can decrease the levels of oxidative stress and complications after OLV.

Trial registration

chictr.org.cn identifier: ChiCTR1800017100.

Driving Pressure during Thoracic Surgery: A Randomized Clinical Trial

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

Driving pressure (plateau minus end-expiratory airway pressure) is a target in patients with acute respiratory distress syndrome, and is proposed as a target during general anesthesia for patients with normal lungs. It has not been reported for thoracic anesthesia where isolated, inflated lungs may be especially at risk.

WHAT THIS ARTICLE TELLS US THAT IS NEW

In a double-blinded, randomized trial (292 patients), minimized driving pressure compared with standard protective ventilation was associated with less postoperative pneumonia or acute respiratory distress syndrome.

BACKGROUND

Recently, several retrospective studies have suggested that pulmonary complication is related with driving pressure more than any other ventilatory parameter. Thus, the authors compared driving pressure-guided ventilation with conventional protective ventilation in thoracic surgery, where lung protection is of the utmost importance. The authors hypothesized that driving pressure-guided ventilation decreases postoperative pulmonary complications more than conventional protective ventilation.

METHODS

In this double-blind, randomized, controlled study, 292 patients scheduled for elective thoracic surgery were included in the analysis. The protective ventilation group (n = 147) received conventional protective ventilation during one-lung ventilation: tidal volume 6 ml/kg of ideal body weight, positive end-expiratory pressure (PEEP) 5 cm H2O, and recruitment maneuver. The driving pressure group (n = 145) received the same tidal volume and recruitment, but with individualized PEEP which produces the lowest driving pressure (plateau pressure-PEEP) during one-lung ventilation. The primary outcome was postoperative pulmonary complications based on the Melbourne Group Scale (at least 4) until postoperative day 3.

RESULTS

Melbourne Group Scale of at least 4 occurred in 8 of 145 patients (5.5%) in the driving pressure group, as compared with 18 of 147 (12.2%) in the protective ventilation group (P = 0.047, odds ratio 0.42; 95% CI, 0.18 to 0.99). The number of patients who developed pneumonia or acute respiratory distress syndrome was less in the driving pressure group than in the protective ventilation group (10/145 [6.9%] vs. 22/147 [15.0%], P = 0.028, odds ratio 0.42; 95% CI, 0.19 to 0.92).

CONCLUSIONS

Application of driving pressure-guided ventilation during one-lung ventilation was associated with a lower incidence of postoperative pulmonary complications compared with conventional protective ventilation in thoracic surgery.

Perioperative interventions for prevention of postoperative pulmonary complications: systematic review and meta-analysis

OBJECTIVE

To identify, appraise, and synthesise the best available evidence on the efficacy of perioperative interventions to reduce postoperative pulmonary complications (PPCs) in adult patients undergoing non-cardiac surgery.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, CINHAL, and CENTRAL from January 1990 to December 2017.

ELIGIBILITY CRITERIA

Randomised controlled trials investigating short term, protocolised medical interventions conducted before, during, or after non-cardiac surgery were included. Trials with clinical diagnostic criteria for PPC outcomes were included. Studies of surgical technique or physiological or biochemical outcomes were excluded.

DATA EXTRACTION AND SYNTHESIS

Reviewers independently identified studies, extracted data, and assessed the quality of evidence. Meta-analyses were conducted to calculate risk ratios with 95% confidence intervals. Quality of evidence was summarised in accordance with GRADE methods. The primary outcome was the incidence of PPCs. Secondary outcomes were respiratory infection, atelectasis, length of hospital stay, and mortality. Trial sequential analysis was used to investigate the reliability and conclusiveness of available evidence. Adverse effects of interventions were not measured or compared.

RESULTS

117 trials enrolled 21 940 participants, investigating 11 categories of intervention. 95 randomised controlled trials enrolling 18 062 participants were included in meta-analysis; 22 trials were excluded from meta-analysis because the interventions were not sufficiently similar to be pooled. No high quality evidence was found for interventions to reduce the primary outcome (incidence of PPCs). Seven interventions had low or moderate quality evidence with confidence intervals indicating a probable reduction in PPCs: enhanced recovery pathways (risk ratio 0.35, 95% confidence interval 0.21 to 0.58), prophylactic mucolytics (0.40, 0.23 to 0.67), postoperative continuous positive airway pressure ventilation (0.49, 0.24 to 0.99), lung protective intraoperative ventilation (0.52, 0.30 to 0.88), prophylactic respiratory physiotherapy (0.55, 0.32 to 0.93), epidural analgesia (0.77, 0.65 to 0.92), and goal directed haemodynamic therapy (0.87, 0.77 to 0.98). Moderate quality evidence showed no benefit for incentive spirometry in preventing PPCs. Trial sequential analysis adjustment confidently supported a relative risk reduction of 25% in PPCs for prophylactic respiratory physiotherapy, epidural analgesia, enhanced recovery pathways, and goal directed haemodynamic therapies. Insufficient data were available to support or refute equivalent relative risk reductions for other interventions.

CONCLUSIONS

Predominantly low quality evidence favours multiple perioperative PPC reduction strategies. Clinicians may choose to reassess their perioperative care pathways, but the results indicate that new trials with a low risk of bias are needed to obtain conclusive evidence of efficacy for many of these interventions.

STUDY REGISTRATION

Prospero CRD42016035662.

Driving pressure guided ventilation

Protective ventilation is a prevailing ventilatory strategy these days and is comprised of small tidal volume, limited inspiratory pressure, and application of positive end-expiratory pressure (PEEP). However, several retrospective studies recently suggested that tidal volume, inspiratory pressure, and PEEP are not related to patient outcomes, or only related when they influence the driving pressure. Therefore, this review introduces the concept of driving pressure and looks into the possibility of driving pressure-guided ventilation as a new ventilatory strategy, especially in thoracic surgery where postoperative pulmonary complications are common, and thus, lung protection is of utmost importance.

Protective ventilation during anaesthesia reduces major postoperative complications after lung cancer surgery: A double-blind randomised controlled trial

BACKGROUND

Thoracic surgery for lung resection is associated with a high incidence of postoperative pulmonary complications. Controlled ventilation with a large tidal volume has been documented to be a risk factor for postoperative respiratory complications after major abdominal surgery, whereas the use of low tidal volumes and positive end-expiratory pressure (PEEP) has a protective effect.

OBJECTIVE

To evaluate the effects of ventilation with low tidal volume and PEEP on major complications after thoracic surgery.

DESIGN

A double-blind, randomised controlled study.

SETTING

A multicentre trial from December 2008 to October 2011.

PATIENTS

A total of 346 patients undergoing lobectomy or pneumonectomy for lung cancer.

MAIN OUTCOME MEASURES

The primary outcome was the occurrence of major postoperative complications (pneumonia, acute lung injury, acute respiratory distress syndrome, pulmonary embolism, shock, myocardial infarction or death) within 30 days after surgery.

INTERVENTIONS

Patients were randomly assigned to receive either lung-protective ventilation (LPV group) [tidal volume 5 ml kg ideal body weight + PEEP between 5 and 8 cmH2O] or nonprotective ventilation (control group) (tidal volume 10 ml kg ideal body weight without PEEP) during anaesthesia.

RESULTS

The trial was stopped prematurely because of an insufficient inclusion rate. Major postoperative complications occurred in 23/172 patients in the LPV group (13.4%) vs. 38/171 (22.2%) in the control group (odds ratio 0.54, 95% confidence interval, 0.31 to 0.95, P = 0.03). The incidence of other complications (supraventricular cardiac arrhythmia, bronchial obstruction, pulmonary atelectasis, hypercapnia, bronchial fistula and persistent air leak) was also lower in the LPV group (37.2 vs. 49.4%, odds ratio 0.60, 95% confidence interval, 0.39 to 0.92, P = 0.02).The duration of hospital stay was shorter in the LPV group, 11 [interquartile range, 9 to 15] days vs. 12 [9 to 16] days, P = 0.048.

CONCLUSION

Compared with high tidal volume and no PEEP, LPV combining low tidal volume and PEEP during anaesthesia for lung cancer surgery seems to improve postoperative outcomes.

TRIALS REGISTRATION

ClinicalTrials.gov number: NCT00805077.

Early corticosteroid treatment for postoperative acute lung injury after lung cancer surgery

Background:

Acute lung injury (ALI) is the most serious pulmonary complication after lung resection. Although the beneficial effects of low-dose corticosteroids have been demonstrated in patients with postoperative ALI, there are limited data on optimal corticosteroid treatment.

Methods:

We retrospectively analyzed 58 patients who were diagnosed with ALI among 7593 patients who underwent lung cancer surgery between January 2009 and December 2016.

Results:

Of the 58 patients, 42 (72%) received corticosteroid treatment within 72 h (early treatment group) and 16 (28%) received corticosteroid treatment more than 72 h after ALI occurred (late treatment group). The early treatment group demonstrated a higher response to corticosteroid treatment compared with the late treatment group (95% versus 69%, respectively, p = 0.014), had an improved lung injury score (86% versus 63%, p = 0.072), and were more likely to be successfully weaned from the ventilator within 7 days (57% versus 39%, p = 0.332). During corticosteroid treatment, the early treatment group had a lower rate of delirium (24% versus 63%, p = 0.012) compared with the late treatment group. No significant differences in length of stay (30 versus 37 days, p = 0.254) or in-hospital mortality (43% versus 38%, p = 0.773) were observed; however, the early treatment group tended to have a higher rate of successful weaning than the late treatment group (p = 0.098, log-rank test).

Conclusions:

Early initiation of corticosteroid treatment improved lung injury and promoted ventilator weaning in patients with ALI following lung resection for lung cancer.

Anesthetic considerations for lung resection: preoperative assessment, intraoperative challenges and postoperative analgesia

This article is intended to provide a general overview of the anesthetic management for lung resection surgery including the preoperative evaluation of the patient, factors influencing the intraoperative anesthetic management and options for postoperative analgesia. Lung cancer is the leading cause of death among cancer patients in the United States. In patients undergoing lung resection, perioperative pulmonary complications are the major etiology of morbidity and mortality. Risk stratification of patients should be part of the preoperative assessment to predict their risk of short-term vs. long-term pulmonary complications. Improvements in surgical technique and equipment have made video assisted thoracoscopy and robotically assisted thoracoscopy the procedures of choice for thoracic surgeries. General anesthesia including lung isolation has become essential for optimizing visualization of the operative lung but may itself contribute to pulmonary complications. Protective lung ventilation strategies may not prevent acute lung injury from one-lung ventilation, but it may decrease the amount of overall lung injury by using small tidal volumes, positive end expiratory pressure, low peak and plateau airway pressures and low inspired oxygen fraction, as well as by keeping surgical time as short as possible. Because of the high incidence of chronic post-thoracotomy pain syndrome following thoracic surgery, which can impact a patient's normal daily activities for months to years after surgery, postoperative analgesia is a necessary part of the anesthetic plan. Multiple options such as thoracic epidural analgesia, intravenous narcotics and several nerve blocks can be considered in order to prevent or attenuate chronic pain syndromes. Enhanced recovery after thoracic surgery is a relatively new topic with many elements taken from the experience with colorectal surgery. The goal of enhanced recovery is to improve patient outcome by improving organ function and decreasing postoperative complications, and therefore decreasing length of hospital stay.

Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation

BACKGROUND

Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation.

METHODS

Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements.

RESULTS

During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The PaO2/FIO2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change.

CONCLUSIONS

During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

Perioperative anesthetic management of patients with malignant pleural mesothelioma undergoing cytoreductive surgery and intraoperative chemotherapy

INTRODUCTION

Cytoreductive surgery with hyperthermic intraoperative chemotherapy (HITHOC) is a therapeutic option for treatment of malignant pleural mesothelioma. Anesthetic management might be challenging.

PATIENTS AND METHODS

A descriptive analysis of a case series is presented. Seven patients with malignant pleural mesothelioma diagnostic undergoing HITHOC surgery were studied. Combined general and epidural anesthesia were administered. An intensive hemodynamic monitorization was implemented. Data regarding perioperative course was analyzed.

RESULTS

Between May 2015 and October 2018 7patients underwent HITHOC procedure. Blood transfusions were administered in all patients, and 5of the 7patients required vasoactive drug administration. Extubation at the end of the procedure was able in 6of the 7patients. The median length of stay in ICU was 4 days, and 29 days for the whole hospitalary stay. No significant postoperative pain was observed.

CONCLUSIONS

HITHOC surgery is a complex procedure in which several hemodynamic changes occur. An intensive intraoperative monitorization was useful for controlling complications.

Effects of Positive End-Expiratory Pressure on Pulmonary Oxygenation and Biventricular Function during One-Lung Ventilation: A Randomized Crossover Study

Although the application of positive end-expiratory pressure (PEEP) can alter cardiopulmonary physiology during one-lung ventilation (OLV), these changes have not been clearly elucidated. This study assessed the effects of different levels of PEEP on biventricular function, as well as pulmonary oxygenation during OLV. Thirty-six lung cancer patients received one PEEP combination of six sequences, consisting of 0 (PEEP_0), 5 (PEEP_5), and 10 cmH₂O (PEEP_10), using a crossover design during OLV. The ratio of arterial oxygen partial pressure to inspired oxygen fraction (P/F ratio), systolic and diastolic echocardiographic parameters were measured at 20 min after the first, second, and third PEEP. P/F ratio at PEEP_5 was significantly higher compared to PEEP_0 (p = 0.014), whereas the P/F ratio at PEEP_10 did not show significant differences compared to PEEP_0 or PEEP_5. Left ventricular ejection fraction (LV EF) and right ventricular fractional area change (RV FAC) at PEEP_10 (EF, p < 0.001; FAC, p = 0.001) were significantly lower compared to PEEP_0 or PEEP_5. RV E/E’ (p = 0.048) and RV myocardial performance index (p < 0.001) at PEEP_10 were significantly higher than those at PEEP_0 or PEEP_5. In conclusion, increasing PEEP to 10 cmH₂O decreased biventricular function, especially on RV function, with no further improvement on oxygenation compared to PEEP 5 cmH₂O during OLV.

Protective ventilation with high versus low positive end-expiratory pressure during one-lung ventilation for thoracic surgery (PROTHOR): study protocol for a randomized controlled trial

BACKGROUND

Postoperative pulmonary complications (PPC) may result in longer duration of in-hospital stay and even mortality. Both thoracic surgery and intraoperative mechanical ventilation settings add considerably to the risk of PPC. It is unclear if one-lung ventilation (OLV) for thoracic surgery with a strategy of intraoperative high positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM) reduces PPC, compared to low PEEP without RM.

METHODS

PROTHOR is an international, multicenter, randomized, controlled, assessor-blinded, two-arm trial initiated by investigators of the PROtective VEntilation NETwork. In total, 2378 patients will be randomly assigned to one of two different intraoperative mechanical ventilation strategies. Investigators screen patients aged 18 years or older, scheduled for open thoracic or video-assisted thoracoscopic surgery under general anesthesia requiring OLV, with a maximal body mass index of 35 kg/m2, and a planned duration of surgery of more than 60 min. Further, the expected duration of OLV shall be longer than two-lung ventilation, and lung separation is planned with a double lumen tube. Patients will be randomly assigned to PEEP of 10 cmH2O with lung RM, or PEEP of 5 cmH2O without RM. During two-lung ventilation tidal volume is set at 7 mL/kg predicted body weight and, during OLV, it will be decreased to 5 mL/kg. The occurrence of PPC will be recorded as a collapsed composite of single adverse pulmonary events and represents the primary endpoint.

DISCUSSION

PROTHOR is the first randomized controlled trial in patients undergoing thoracic surgery with OLV that is adequately powered to compare the effects of intraoperative high PEEP with RM versus low PEEP without RM on PPC. The results of the PROTHOR trial will support anesthesiologists in their decision to set intraoperative PEEP during protective ventilation for OLV in thoracic surgery.

TRIAL REGISTRATION

The trial was registered in clinicaltrials.gov ( NCT02963025 ) on 15 November 2016.