The impact of different inspired oxygen concentrations combined with nebulized prostaglandin E1 on oxygenation in patients undergoing one-lung ventilation: a randomized controlled trial

BACKGROUND

One-lung ventilation (OLV) requires a high inspired oxygen concentration (FiO2) to promote oxygenation improvement, yet it increases the risk of postoperative pulmonary complications. Therefore, this study aimed to investigate the effects of prostaglandin E1 (PGE1) in reducing FiO2 during general anesthesia and mechanical ventilation on oxygenation and postoperative complications in patients undergoing OLV.

METHOD

A total of 120 patients scheduled for elective left thoracotomy esophageal cancer surgery were randomly divided into four groups (n = 30): Group L (FiO2 = 0.4, PGE1 = 0.1 µg /kg), Group M (FiO2 = 0.5, PGE1 = 0.1 µg /kg), Group H (FiO2 = 0.6, PGE1 = 0.1 µg /kg), and Group C (FiO2 = 0.4, normal saline solution). The primary outcome was oxygenation during OLV. Secondary outcomes included intrapulmonary shunt (Qs/Qt), incidence of postoperative pulmonary complications, and changes in inflammatory cytokines.

RESULTS

Group H exhibited higher PaO2 values than Groups L, M, and C at all time points T1-T6. Group M also showed higher PaO2 values than Groups L and C at all time points T1-T6. In contrast, Group L demonstrated significantly higher PaO2 values than Group C at time points T2-T4. The nebulization groups (L, M, H) had significantly higher PaO2/FiO2 than Group C at time points T2-T4. Group H had higher Qs/Qt values than Groups L, M, and C at all time points T1-T6. At time points T2-T4, Group L had significantly lower Qs/Qt values compared to both Group C and Group M, which in turn had significantly lower values than Group C. Regarding interleukin-6 (IL-6) levels, Group C was significantly higher than the nebulization groups at time points T5-T8, while Group L was significantly lower than Groups M and H at T8. In terms of tumor necrosis factor-α(TNF-α) levels, Group C was significantly higher than the nebulization groups at time points T7-T8. With respect to clinical pulmonary infection score (CPIS), Group L was significantly lower than Groups M, H, and C. There was no statistically significant difference in the overall incidence of postoperative complications probability (PPCs) among the four groups, nor were there statistically significant differences in pneumothorax, pulmonary infection, anastomotic leakage, ICU stay duration, or total hospital stay duration among the groups.

CONCLUSION

PGE1 demonstrates a significant advantage in reducing the incidence of hypoxemia, effectively improving oxygenation status in patients undergoing OLV with lower FiO2. Given the effects of PGE1 on oxygenation and inflammatory factors, as well as the CPIS, the results of this study suggest that a clinical regimen of 0.4 FiO2 + 0.1 µg /kg PGE1 is appropriate.

TRIAL REGISTRATION

Chictr.org.cn identifier: Retrospectively registered, ChiCTR1800018288(09/09/2018).

Effect of Electrical Impedance Tomography-Guided Early Mobilization in Patients After Major Upper Abdominal Surgery: Protocol for a Prospective Cohort Study

Background: Pulmonary complications are common in patients after upper abdominal surgery, resulting in poor clinical outcomes and increased costs of hospitalization. Enhanced Recovery After Surgery Guidelines strongly recommend early mobilization post-operatively; however, the quality of the evidence is poor, and indicators for quantifying the effectiveness of early mobilization are lacking. This study will evaluate the effectiveness of early mobilization in patients undergoing an upper abdominal surgery using electrical impedance tomography (EIT). Specifically, we will use EIT to assess and compare the lung ventilation distribution among various regions of interest (ROI) before and after mobilization in this patient population. Additionally, we will assess the temporal differences in the distribution of ventilation in various ROI during mobilization in an effort to develop personalized activity programs for this patient population.

Methods: In this prospective, single-center cohort study, we aim to recruit 50 patients after upper abdominal surgery between July 1, 2021 and June 30, 2022. This study will use EIT to quantify the ventilation distribution among different ROI. On post-operative day 1, the nurses will assist the patient to sit on the chair beside the bed. Patient's heart rate, blood pressure, oxygen saturation, respiratory rate, and ROI 1-4 will be recorded before the mobilization as baseline. These data will be recorded again at 15, 30, 60, 90, and 120 min after mobilization, and the changes in vital signs and ROI 1-4 values at each time point before and after mobilization will be compared.

Ethics and Dissemination: The study protocol has been approved by the Institutional Review Board of Liaocheng Cardiac Hospital (2020036). The trial is registered at chictr.org.cn with identifier ChiCTR2100042877, registered on January 31, 2021. The results of the study will be presented at relevant national and international conferences and submitted to international peer-reviewed journals. There are no plans to communicate results specifically to participants. Important protocol modifications, such as changes to eligibility criteria, outcomes, or analyses, will be communicated to all relevant parties (including investigators, Institutional Review Board, trial participants, trial registries, journals, and regulators) as needed via email or in-person communication.

Effects of Thoracic Epidural Anesthesia on Systemic and Local Inflammatory Responses in Patients Undergoing Lung Cancer Surgery: A Randomized Controlled Trial

OBJECTIVE

Inflammatory responses play major roles in the development of acute lung injury following lung cancer surgery. The authors tested the hypothesis that thoracic epidural anesthesia (TEA) during surgery could attenuate both systemic and local inflammatory cytokine productions in patients undergoing lung cancer surgery.

DESIGN

A prospective randomized controlled trial.

SETTING

At Keio University Hospital, Tokyo, Japan.

PARTICIPANTS

Patients scheduled for lung cancer surgery.

INTERVENTIONS

Sixty patients were randomly allocated into two groups (n = 30 each group): the epidural group (group E), in which anesthesia was maintained with propofol, fentanyl, rocuronium, and epidural anesthesia with 0.25% levobupivacaine; or the remifentanil group (group R), in which a remifentanil infusion was used as a potent analgesia instead of epidural anesthesia.

MEASUREMENTS AND MAIN RESULTS

The lung epithelial lining fluid (ELF) and blood sampling were collected prior to one-lung ventilation (OLV) initiation (T1) and at 30 minutes after the end of OLV (T2). The concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 in the ELF at T2 were increased significantly compared with those at T1 in both groups. The ELF concentration of IL-6 in group E was significantly lower than that in group R at T2 (median [interquartile range]: 39.7 [13.8-80.2] versus 76.1 [44.9-138.2], p = 0.008). Plasma IL-6 concentrations at T2, which increased in comparison to that at T1, were not significantly different between the two groups. The plasma concentrations of TNF-α did not change in both groups.

CONCLUSIONS

This randomized clinical trial suggested that TEA could attenuate local inflammatory responses in the lungs during lung cancer surgery.

DGLA from the Microalga Lobosphaera Incsa P127 Modulates Inflammatory Response, Inhibits iNOS Expression and Alleviates NO Secretion in RAW264.7 Murine Macrophages

Microalgae have been considered as a renewable source of nutritional, cosmetic and pharmaceutical compounds. The ability to produce health-beneficial long-chain polyunsaturated fatty acids (LC-PUFA) is of high interest. LC-PUFA and their metabolic lipid mediators, modulate key inflammatory pathways in numerous models. In particular, the metabolism of arachidonic acid under inflammatory challenge influences the immune reactivity of macrophages. However, less is known about another omega-6 LC-PUFA, dihomo-γ-linolenic acid (DGLA), which exhibits potent anti-inflammatory activities, which contrast with its delta-5 desaturase product, arachidonic acid (ARA). In this work, we examined whether administrating DGLA would modulate the inflammatory response in the RAW264.7 murine macrophage cell line. DGLA was applied for 24 h in the forms of carboxylic (free) acid, ethyl ester, and ethyl esters obtained from the DGLA-accumulating delta-5 desaturase mutant strain P127 of the green microalga Lobosphaera incisa. DGLA induced a dose-dependent increase in the RAW264.7 cells’ basal secretion of the prostaglandin PGE1. Upon bacterial lipopolysaccharide (LPS) stimuli, the enhanced production of pro-inflammatory cytokines, tumor necrosis factor alpha (TNFα) and interleukin 1β (IL-1β), was affected little by DGLA, while interleukin 6 (IL-6), nitric oxide, and total reactive oxygen species (ROS) decreased significantly. DGLA administered at 100 µM in all forms attenuated the LPS-induced expression of the key inflammatory genes in a concerted manner, in particular iNOS, IL-6, and LxR, in the form of free acid. PGE1 was the major prostaglandin detected in DGLA-supplemented culture supernatants, whose production prevailed over ARA-derived PGE2 and PGD2, which were less affected by LPS-stimulation compared with the vehicle control. An overall pattern of change indicated DGLA’s induced alleviation of the inflammatory state. Finally, our results indicate that microalgae-derived, DGLA-enriched ethyl esters (30%) exhibited similar activities to DGLA ethyl esters, strengthening the potential of this microalga as a potent source of this rare anti-inflammatory fatty acid.

Review 2: Primary graft dysfunction after lung transplant-pathophysiology, clinical considerations and therapeutic targets

Primary graft dysfunction (PGD) is one of the most common complications in the early postoperative period and is the most common cause of death in the first postoperative month. The underlying pathophysiology is thought to be the ischaemia–reperfusion injury that occurs during the storage and reperfusion of the lung engraftment; this triggers a cascade of pathological changes, which result in pulmonary vascular dysfunction and loss of the normal alveolar architecture. There are a number of surgical and anaesthetic factors which may be related to the development of PGD. To date, although treatment options for PGD are limited, there are several promising experimental therapeutic targets. In this review, we will discuss the pathophysiology, clinical management and potential therapeutic targets of PGD.

Limb remote ischemic preconditioning attenuates lung injury after pulmonary resection under propofol-remifentanil anesthesia: a randomized controlled study

BACKGROUND

Remote ischemic preconditioning (RIPC) may confer the protection in critical organs. The authors hypothesized that limb RIPC would reduce lung injury in patients undergoing pulmonary resection.

METHODS

In a randomized, prospective, parallel, controlled trial, 216 patients undergoing elective thoracic pulmonary resection under one-lung ventilation with propofol-remifentanil anesthesia were randomized 1:1 to receive either limb RIPC or conventional lung resection (control). Three cycles of 5-min ischemia/5-min reperfusion induced by a blood pressure cuff served as RIPC stimulus. The primary outcome was PaO2/FIO2. Secondary outcomes included other pulmonary variables, the incidence of in-hospital complications, markers of oxidative stress, and inflammatory response.

RESULTS

Limb RIPC significantly increased PaO2/FIO2 compared with control at 30 and 60 min after one-lung ventilation, 30 min after re-expansion, and 6 h after operation (238 ± 52 vs. 192 ± 67, P = 0.03; 223 ± 66 vs. 184 ± 64, P = 0.01; 385 ± 61 vs. 320 ± 79, P = 0.003; 388 ± 52 vs. 317 ± 46, P = 0.001, respectively). In comparison with control, it also significantly reduced serum levels of interleukin-6 and tumor necrosis factor-α at 6, 12, 24, and 48 h after operation and malondialdehyde levels at 60 min after one-lung ventilation and 30 min after re-expansion (all P < 0.01). The incidence of acute lung injury and the length of postoperative hospital stay were markedly reduced by limb RIPC compared with control (all P < 0.05).

CONCLUSION

Limb RIPC attenuates acute lung injury via improving intraoperative pulmonary oxygenation in patients without severe pulmonary disease after lung resection under propofol-remifentanil anesthesia.

Surgical quality of care in esophageal malignancies

Aim: Esophagectomy is the primary surgical treatment for localized malignant neoplasms of the esophagus, and while outcomes have shown that substantial improvement has been made, the ceiling for improvement is still high. Methods: A total of 2506 publications published from January 2002 to March 2012 were identified from PubMed, MEDLINE and the Cochrane Library using the keywords: ‘esophagectomy’, ‘esophagus’, ‘neoplasm’ and ‘cancer’ to identify quality key surgical articles in esophagectomy that were broken down into three groups: preoperative, intraoperative and postoperative care. Discussion: There have been limited preoperative surgical trials, mostly in preoperative antibiotic use, which have led to changes in surgical management. Key and substantial changes have occurred in the intraoperative management for esophageal malignancies around surgical anastomosis technique and anesthesia. Nutritional outcomes still remain a key challenge, and currently there is no established standard of care in the postoperative management of esophagectomy patients. Conclusion: We established quality parameters for leak rates, overall morbidity and mortality, and these form the foundation from which all esophageal surgeons should rank their results. We then utilized the techniques described above to maintain those rates or, better yet, to significantly improve those rates in each surgeons’ practice.

Does perioperative prostaglandin E1 affect survival of patients with esophageal cancer?

AIM: To detect the effect of intraoperative prostaglandin E1 (PGE1) infusion on survival of esophagectomized patients due to cancer.

METHODS: In this preliminary study, a double blinded placebo based clinical trial was performed. Thirty patients with esophageal cancer scheduled for esophagectomy via the transthoracic approach were randomized by a block randomization method, in two equal groups: PGE1 group - infusion of PGE1 (20 ng/kg per minute) in the operating room and placebo group - saline 0.9% with the same volume and rate. The infusion began before induction of anesthesia and finished just before transfer to the intensive care unit. The patients, anesthetist, intensive care physicians, nurses and surgeons were blinded to both study groups. All the patients were anesthetized with the same method. For postoperative pain control, a thoracic epidural catheter was placed for all patients before induction of anesthesia. We followed up the patients until October 2010. Basic characteristics, duration of anesthesia, total surgery and thoracotomy time, preoperative hemoglobin, length of tumor, grade of histological differentiation, disease stage, number of lymph nodes in the resected mass, number of readmissions to hospital, total duration of readmission and survival rates were compared between the two groups. Some of the data originates from the historical data reported in our previous study. We report them for better realization of the follow up results.

RESULTS: The patients’ characteristics and perioperative variables were compared between the two groups. There were no significant differences in age (P = 0.48), gender (P = 0.27), body mass index (P = 0.77), American Society of Anesthesiologists physical status more than I (P = 0.71), and smoking (P = 0.65). The PGE1 and placebo group were comparable in the following variables: duration of anesthesia (277 ± 50 vs 270 ± 67, P = 0.86), duration of thoracotomy (89 ± 35 vs 96 ± 19, P = 0.46), duration of operation (234 ± 37 vs 240 ± 66, P = 0.75), volume of blood loss during operation (520 ± 130 vs 630 ± 330, P = 0.34), and preoperative hemoglobin (14.4 ± 2 vs 14.7 ± 1.9, P = 0.62), respectively. No hemodynamic complications requiring an infusion of dopamine or cessation of the PGE1 infusion were encountered. Cancer variables were compared between the PGE1 and placebo group. Length of tumor (11.9 ± 3 vs 12.3 ± 3, P = 0.83), poor/undifferentiated grade of histological differentiation [3 (20%) vs 3 (20%), P = 0.78], disease stage III [5 (33.3%), 4 (26.7%), P = 0.72] and more than 3 lymph nodes in the resected mass [3 (20%) vs 2 (13.3%), P = 0.79] were similar in both groups. All the patients were discharged from hospital except one patient in the control group who died because of a post operative myocardial infarction. No life threatening postoperative complication occurred in any patient. The results of outcome and survival were the same in PGE1 and placebo group: number of readmissions (2.1 ± 1 vs 1.9 ± 1, P = 0.61), total duration of readmission (27 ± 12 vs 29 ± 12, P = 0.67), survival rate (10.1 ± 3.8 vs 9.6 ± 3.4, P = 0.71), overall survival rate after one year [8 (53.3%) vs 7 (47%), P = 0.72], overall survival rate after two years [3 (20%) vs 3 (20%), P = 0.99], and overall survival rate after three years [0 vs 1 (6.7%), P = 0.99], respectively.

CONCLUSION: In conclusion, PGE1 did not shorten or lengthen the survival of patients with esophageal cancer. Larger studies are suggested.