Effect of re-expansion after short-period lung collapse on pulmonary capillary permeability and pro-inflammatory cytokine gene expression in isolated rabbit lungs

Morbidity and neurodevelopmental outcomes at 2 years in preterm infants undergoing percutaneous transcatheter closure vs. surgical ligation of the PDA

OBJECTIVE

Review a cohort of preterm infants ≤29 weeks of gestation at birth and compare morbidities and neurodevelopmental outcomes based on PDA status and type of PDA closure.

STUDY DESIGN

Single center observational retrospective-prospective case control study of premature infants who had no hsPDA, underwent surgical ligation or percutaneous transcatheter closure of the PDA. Neurodevelopmental testing was done using the Bayley Scales of Infant Development 3rd ed.

RESULTS

The percutaneous transcatheter closure group had an older post menstrual age and greater weight at the time of procedure, and started enteral feeds and achieved room air status at an earlier post procedure day. Infants in the surgical ligation group were more likely to experience vocal cord paralysis. There was no difference in neurodevelopmental outcomes between groups.

CONCLUSION

Waiting for infants to achieve the appropriate size for percutaneous transcatheter closure of the PDA may lead to reduced short-term complications without increasing the risk of neurodevelopmental impairment.

Unilobar re-expansion pulmonary oedema following removal of a large intra-thoracic mass

Re-expansion pulmonary oedema (RPE) is not so rare complication associated with sudden expansion of a collapsed lung. RPE has been most frequently reported following rapid drainage of a large pneumothorax or chronic pleural effusion. Development of RPE following removal of a large intrathoracic mass is not commonly recognised, though sporadic reports exist in the literature. RPE can be fatal, but early diagnosis with appropriate management usually leads to satisfactory outcomes. We report a case of RPE, which occurred following removal of a giant intra-thoracic mass and its subsequent management and outcome with a brief review of relevant literature.

[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.

The Year in Thoracic Anesthesia: Selected Highlights From 2020

Selected highlights in thoracic anesthesia in 2020 include updates in the preoperative assessment and prehabilitation of patients undergoing thoracic surgery; updates in one-lung ventilation (OLV) pertaining to the devices used for OLV; the use of dexmedetomidine for lung protection during OLV and protective ventilation, recommendations for the care of thoracic surgical patients with coronavirus disease 2019; a review of recent meta-analyses comparing truncal blocks with paravertebral and thoracic epidural blocks; and a review of outcomes after initiating the enhanced recovery after surgery guidelines for lung and esophageal surgery.

PLCε1 mediates one-lung ventilation injury by regulating the p38/RhoA/NFκB activation loop

BACKGROUND

Phospholipase C epsilon-1 (PLCε1) might be a novel and potential target in treating inflammatory conditions. In the present study, we aimed to clarify whether PLCε1 is involved in lung injury caused by one-lung ventilation (OLV) and to elucidate the potential molecular mechanism of PLCε1-mediated signaling pathway on OLV induced inflammatory response and injury.

METHODS

Male Sprague-Dawley (SD) rats were divided into wide-type (PLCε1-WT) group and PLCε1-KO group, and were treated with OLV for 0.5 h, 1 h, and 2 h respectively. Observation of lung tissue injury in rats was performed by Hematoxylin and eosin (HE) staining and Wet/dry (W/D) radios. In addition, pulmonary microvascular endothelial cells (PMVECs) transfected with PLCε1-si RNA, were stimulated by lipopolysaccharide (LPS). To explore the possible roles of PLCε1 in the OLV induced inflammatory injury and the involved pathway underlying, the lung tissue and bronchoalveolar lavage fluids (BALF) of OLV rats, as well as the PMVECs were prepared for further analysis. Enzyme-linked immunoassay (ELISA) was used to detect the expression of pro-inflammatory factors. The activities of related pathway proteins (NF-κB, phospho-p38, p38, phospho-ERK1/2, ERK1/2, RhoA and ROCK) were also detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis.

RESULTS

Compared to the PLCε1-WT rats, PLCε1-KOrats exhibited marked alleviation of lung inflammation as shown by great reduction in lung wet/dry weight ratios, decreases in the expressions of pro-inflammatory mediators, and declines in the number of neutrophils and the protein concentration in bronchoalveolar lavage fluid (BALF). Moreover, the increased expressions of RhoA and NF-κB p65 mRNA induced by OLV were significantly inhibited in PLCε1-KO rats. In LPS treated PMVECs, PLCε1-si RNA transfection ones also showed the decrease expression of proinflammatory mediators, reduction in p38 phosphorylation levels and downregulation of RhoA/ROCK signaling activation. Co-cultured with PLCε1-si RNA and BTRB796 (p38 inhibitors) in LPS-stimulated PMVECs resulted in a significant reduction in RhoA and NF-κB activity. In addition, treatment with either ROCK inhibitor (Y-27632) or dominant negative mutant of RhoA (RhoT19 N) significantly reduced the expression of NF-κB in PLCε1-si RNA treated PMVECs.

CONCLUSION

The results indicated that PLCε1 played an important role in the inflammatory response induced by OLV. Moreover, through promoting p38/RhoA/ROCK activation loop, PLCε1 promoted NF-κB activation and thereby increased the expressions of inflammatory mediators, which induced the PMVECs inflammation and subsequent injury. The results of this study provide a potential therapeutic target for the reduction of inflammatory response in patients with OLV.

Strategic ventilation reduces non-ventilated contralateral lung injury induced by one-lung ventilation in rabbits

ABSTRACT One lung ventilation (OLV) often results in trauma to the unventilated contralateral lung. This study aims to evaluate the effects of different OLV regimens on the injury of the unventilated contralateral lung to identify the best conditions for OLV. Forty rabbits were divided into five groups: a sham group, OLV group I (fraction of inspired oxygen (FIO2) 1.0, tidal volume (VT) 8mL/kg, respiratory rate (R) 40 breaths/min and inspiratory/expiratory ratio (I:E) 1:2), OLV group II (FIO2=1.0, VT 8mL/kg, R 40 breaths/min, I:E 1:2, and positive end-expiratory pressure (PEEP) 5 cm H2O), OLV group III (FIO2 1.0, VT 6mL/kg, R 40 breaths/min, I:E 1:2 and PEEP 5 cm H2O) and OLV group IV (FIO2 0.8, VT 6mL/kg, R 40 breaths/min, I:E 1:2 and PEEP 5 cm H2O). Animals from all OLV groups received two-lung ventilation (TLV) to establish a baseline, followed by one of the indicated OLV regimens. The rabbits in the sham group were intubated through trachea and ventilated with fresh air. Arterial blood gas samples were collected, lung injury parameters were evaluated, and the concentrations of TNF-α and IL-8 in bronchoalveolar lavage fluid (BALF) and pulmonary surfactant protein A (SPA) in the unventilated lung were also measured. In OLV group I, the unventilated left lung had higher TNF-α, IL-8 and lung injury score but lower SPA than the ventilated right lung. In OLV groups I to III, the concentrations of TNF-α, IL-8 and lung injury score in the left lung decreased but SPA increased. No differences in these parameters between OLV groups III and IV were observed. Strategic ventilation designed for OLV groups III and IV reduced OLV-induced injury of the non-ventilated contralateral lung in rabbits.

Activation of PI3K/Akt/HIF-1α Signaling is Involved in Lung Protection of Dexmedetomidine in Patients Undergoing Video-Assisted Thoracoscopic Surgery: A Pilot Study

Background

Lung resection and one lung ventilation (OLV) during video-assisted thoracoscopic surgery (VATS) may lead to acute lung injury. Dexmedetomidine (DEX), a highly selective α₂ adrenergic receptor agonist, improves arterial oxygenation in adult patients undergoing thoracic surgery. The aim of this pilot study was to explore possible mechanism related to lung protection of DEX in patients undergoing VATS.

Patients and Methods

Seventy-four patients scheduled for VATS were enrolled in this study. Three timepoints (before anesthesia induction (T₀), 40 min after OLV (T₁), and 10 min after two-lung ventilation (T₂)) of arterial blood gas were obtained. Meanwhile, lung histopathologic examination, immunohistochemistry analysis (occludin and ZO-1), levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in lung tissue and plasma, and activation of phosphoinositide-3-kinase (PI3K)/AKT/hypoxia-inducible factor (HIF)-1α signaling were detected. Postoperative outcomes including duration of withdrawing the pleural drainage tube, length of hospital stay, hospitalization expenses, and postoperative pulmonary complications (PPCs) were also recorded.

Results

Sixty-seven patients were randomly divided into DEX group (group D, n=33) and control group (group N, n=34). DEX improved oxygenation at T₁ and T₂ (group D vs group N; T₁: 191.8 ± 49.8 mmHg vs 159.6 ± 48.1 mmHg, P = 0.009; T₂: 406.0 mmHg [392.2–423.7] vs 374.5 mmHg [340.2–378.2], P = 0.001). DEX alleviated the alveolar capillary epithelial structure damage, increased protein expression of ZO-1 and occludin, inhibited elevation of the expression of TNF-α and IL-6 in lung tissue and plasma, and increased protein expression of p-PI3K, p-AKT and HIF-1α. Dex administered had better postoperative outcomes with less risk of PPCs and hospitalization expenses as well as shorter duration of withdrawing the pleural drainage tube and length of hospital stay.

Conclusion

Activation of PI3K/Akt/HIF-1α signaling might be involved in lung protection of DEX in patients undergoing VATS.

Pulmonary protection of transcutaneous electrical acupoint stimulation in gynecological laparoscopic surgery: A randomized controlled trial

Laparoscopy is performed worldwide due to its limited side effects and optimal treatment efficacy. However, it also has adverse effects, including atelectasis and ischemia-reperfusion injury, due to CO₂ accumulation during ventilation in a head-down position, which may result in severe disorders and adversely affecting postoperative recovery, prolonging hospitalization. The present study was performed to assess whether transcutaneous electrical acupoint stimulation (TEAS) protects against lung injury occurring during gynecological laparoscopic surgery. Patients were randomly allocated to two groups: Control group (received no stimulation) and TEAS group (patients treated with TEAS on BL13, LI4 and LU5). The mean arterial pressure, heart rate and oxygen saturation were recorded at the time-points of arriving in the operating room (T₀), immediately prior to induction of the pneumoperitoneum (T₁), immediately after the end of pneumoperitoneum (T₂) and on leaving the operating room (T₃). Arterial blood gas analysis was performed to record the pH, determine the partial pressure of carbon dioxide and calculate the oxygenation index (OI) at T_0–3. Blood samples were taken from the peripheral vein for determination of the serum concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-1β at T₀ and T₃. Post-operative pulmonary complications occurring during the first five days after surgery were also recorded. A total of 100 patients were initially enrolled and 80 patients were analysed. The results indicated that the OI in the control group was significantly lower than that in the TEAS group at the T₂ and T₃ time-points. The serum concentrations of TNF-α and IL-1β were significantly increased following surgery, while the extent of these increases was lower in the TEAS group compared with that in the control group. The incidence of post-operative pulmonary complications was significantly lower in the TEAS group. It was therefore indicated that TEAS protect against lung injury as a complication of gynecological laparoscopic surgery. The present study was registered at http://www.clinicaltrials.gov prior to enrollment of the patients (no. NCT02850471).

Incidence of reexpansion pulmonary edema in minimally invasive cardiac surgery

Minimally invasive cardiac surgery requires fewer blood transfusions and mediastinitis is less frequently observed compared to conventional median sternotomy surgical intervention, and it leads to earlier recovery and discharge. However, once reexpansion pulmonary edema occurs, the patient requires long-term management in the intensive care unit. This retrospective study was performed to investigate the incidence of reexpansion pulmonary edema in minimally invasive cardiac surgery. Patients who underwent minimally invasive cardiac valve surgery using cardiopulmonary bypass and port-access by a minimal right lateral thoracic incision between January 2010 and January 2018 were enrolled in this single-center retrospective study, which was approved by the institutional review board of Japanese Red Cross Nagoya Daiichi Hospital (Nagoya, Japan), and the requirement for written informed consent was waived. All data were collected from electronic charts. The primary outcome was the incidence rate of reexpansion pulmonary edema in patients undergoing minimally invasive cardiac surgery. A total of 662 patients underwent minimally invasive cardiac surgery, and we analyzed 651 of these cases. No case of reexpansion pulmonary edema was observed in this study. The statistically-calculated incidence rate of reexpansion pulmonary edema was less than 0.6% (95% confidence interval: 0.0–0.6). The incidence of cerebral infarction was 0.92% (n = 6). Intensive care unit stay days, hospital stay days after surgery, and the death rate after 30 days were 1.5 ± 2.0 days, 9.6 ± 3.9 days, and 0.15%, respectively. Although there was no incidence of clinical reexpansion pulmonary edema in this study, the predicted incidence of reexpansion pulmonary edema by statistical analysis was less than 0.6%.

Use of lung-protective strategies during one-lung ventilation surgery: a multi-institutional survey

Background

Limited evidence suggests that intraoperative lung-protective ventilation (LPV) during one-lung ventilation (OLV) may reduce respiratory complications after thoracic surgery. Little is known about LPV practices during OLV. Our purpose was to assess the state of practice/perspectives of anesthesiologists regarding LPV during elective OLV.

Methods

We conducted a multi-institutional cross-sectional survey of anesthesiologists performing OLV at high-volume Canadian tertiary/university centers. The survey was designed, refined and distributed by a multi-disciplinary team using the Dillman method. Univariable and multivariable analyses were used.

Results

Seventy-five (63%) of 120 eligible respondents completed the survey. Although the critical care literature focuses on minimizing tidal volume (TV) as the central strategy of LPV, most respondents (89%, n=50/56) focused on minimizing peak airway pressure (PAP) as their primary strategy of intraoperative LPV. Only 64% (n=37/58) reported actively trying to minimize TV. While 32% (n=17/54) were unsure about the current evidence regarding LPV, 67% (n=36/54) believed that the evidence favoured their use during OLV. Perceived clinical and institutional barriers were the only predictors of reduced attempts to minimize TV on univariate analyses. In multivariable/adjusted analyses, perceived institutional barriers were the only predictors of reduced attempts to minimize TV with adjusted odds ratio of 0.1 (95% CI: 0.03-0.6).

Conclusions

Most anesthesiologists defined low PAP as the primary strategy of LPV during OLV and attempted to minimize it. This study is the first to assess the practice/perspectives of anesthesiologists regarding LPV during OLV and also the first to explore predictors of LPV use. Randomized trials are currently ongoing. However, this study suggests that institutional barriers may subvert future knowledge translation and need to be addressed.

Hepatic hydrothorax: An update and review of the literature

This review considers the modern concepts of pathogenesis, diagnostic methods, and treatment principles of hepatic hydrothorax (HH). HH is the excessive (> 500 mL) accumulation of transudate in the pleural cavity in patients with decompensated liver cirrhosis but without cardiopulmonary and pleural diseases. It causes respiratory failure which aggravates the clinical course of liver cirrhosis, and the emergence of spontaneous bacterial pleural empyema may be the cause of death. The information was collected from the PubMed database, the Google Scholar retrieval system, the Cochrane reviews, and the reference lists from relevant publications for 1994-2016 using the keywords: “liver cirrhosis”, “portal hypertension”, “hepatic hydrothorax”, “pathogenesis”, “diagnostics”, and “treatment”. To limit the scope of this review, only articles dealing with uncomplicated hydrothorax in patients with liver cirrhosis were included. The analysis of the data showed that despite the progress of modern hepatology, the presence of HH is associated with poor prognosis and high mortality. Most patients suffering from it are candidates for orthotopic liver transplantation. In routine clinical practice, stratification of the risk for an adverse outcome and the subsequent determination of individual therapeutic strategies may be the keys to the successful management of the patient’s condition. The development of pathogenetic pharmacotherapy and optimization of minimally invasive treatment will improve the quality of life and increase the survival rate among patients with HH.

Immunological and Inflammatory Impact of Non-Intubated Lung Metastasectomy

Background: We hypothesized that video-assisted thoracic surgery (VATS) lung metastasectomy under non-intubated anesthesia may have a lesser immunological and inflammatory impact than the same procedure under general anesthesia. Methods: Between December 2005 and October 2015, 55 patients with pulmonary oligometastases (at the first episode) successfully underwent VATS metastasectomy under non-intubated anesthesia. Lymphocytes subpopulation and interleukins 6 and 10 were measured at different intervals and matched with a control group composed of 13 patients with similar clinical features who refused non-intubated surgery. Results: The non-intubated group demonstrated a lesser reduction of natural killer lymphocytes at 7 days from the procedure (p = 0.04) compared to control. Furthermore, the group revealed a lesser spillage of interleukin 6 after 1 (p = 0.03), 7 (p = 0.04), and 14 (p = 0.05) days. There was no mortality in any groups. Major morbidity rate was significantly higher in the general anesthesia group 3 (5%) vs. 3 (23%) (p = 0.04). The median hospital stay was 3.0 vs. 3.7 (p = 0.033) days, the estimated costs with the non-intubated procedure was significantly lower, even excluding the hospital stay. Conclusions: VATS lung metastasectomy in non-intubated anesthesia had significantly lesser impact on both immunological and inflammatory response compared to traditional procedure in intubated general anesthesia.

Comparison of pressure-controlled ventilation with volume-controlled ventilation during one-lung ventilation: a systematic review and meta-analysis

BACKGROUND

Not only arterial hypoxemia but acute lung injury also has become the major concerns of one-lung ventilation (OLV). The use of pressure-controlled ventilation (PCV) for OLV offers the potential advantages of lower airway pressure and intrapulmonary shunt, which result in a reduced risk of barotrauma and improved oxygenation, respectively.

METHODS

We searched Medline, Embase, the Cochrane central register of controlled trials and KoreaMedto find publications comparing the effects of PCV with those of volume-controlled ventilation (VCV) during intraoperative OLV in adults. A meta-analysis of randomized controlled trials was performed using the Cochrane Review Methods.

RESULTS

Six studies (259 participants) were included. The PaO2/FiO2 ratio in PCV was higher than in VCV [weighted mean difference (WMD) = 11.04 mmHg, 95 % confidence interval (CI) = 0.30 to 21.77, P = 0.04, I(2) = 3 %] and peak inspiratory pressure was significantly lower in PCV (WMD = -4.91 cm H2O, 95 % CI = -7.30 to -2.53, P < 0.0001, I (2) = 91 %). No differences in PaCO2, tidal volume, heart rate and blood pressure were observed. There were also no differences incompliance, plateau and mean airway pressure.

CONCLUSIONS

Our meta-analysis provided the evidence of improved oxygenation in PCV. However, it is difficult to draw any definitive conclusions due to the fact that the duration of ventilation in the studies reviewed was insufficient to reveal clinically relevant benefits or disadvantages of PCV. Significantly lower peak inspiratory pressure is the advantage of PCV.

An uncommon complication of a common clinical scenario: exploring reexpansion pulmonary edema with a case report and literature review

Reexpansion pulmonary edema (RPE) is a rare complication that can occur after rapid reinflation of the lung following thoracentesis of a pleural effusion or chest tube drainage of pneumothorax. The severity in clinical presentation can be widely varied from radiographic changes only to rapidly progressive respiratory failure requiring mechanical ventilation. The quick nature of onset and potential for serious decline in a previously stable patient makes it important to prepare, recognize, diagnose, and appropriately manage patients who develop RPE. The standard treatment for RPE consists of supportive care, and there are certain measures that may be taken to reduce the risk, including limiting the amount drained and avoiding excessive negative pleural pressure. Exactly how to prevent RPE remains unclear, however, and varying recommendations exist. This is a case report of RPE after thoracentesis for a pleural effusion and a brief review of literature to date, including potential preventative strategies.

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

Lung injury is the leading cause of death after thoracic surgery. Initially recognized after pneumonectomy, it has since been described after any period of 1-lung ventilation (OLV), even in the absence of lung resection. Overhydration and high tidal volumes were thought to be responsible at various points; however, it is now recognized that the pathophysiology is more complex and multifactorial. All causative mechanisms known to trigger ventilator-induced lung injury have been described in the OLV setting. The ventilated lung is exposed to high strain secondary to large, nonphysiologic tidal volumes and loss of the normal functional residual capacity. In addition, the ventilated lung experiences oxidative stress, as well as capillary shear stress because of hyperperfusion. Surgical manipulation and/or resection of the collapsed lung may induce lung injury. Re-expansion of the collapsed lung at the conclusion of OLV invariably induces duration-dependent, ischemia-reperfusion injury. Inflammatory cytokines are released in response to localized injury and may promote local and contralateral lung injury. Protective ventilation and volatile anesthesia lessen the degree of injury; however, increases in biochemical and histologic markers of lung injury appear unavoidable. The endothelial glycocalyx may represent a common pathway for lung injury creation during OLV, because it is damaged by most of the recognized lung injurious mechanisms. Experimental therapies to stabilize the endothelial glycocalyx may afford the ability to reduce lung injury in the future. In the interim, protective ventilation with tidal volumes of 4 to 5 mL/kg predicted body weight, positive end-expiratory pressure of 5 to 10 cm H2O, and routine lung recruitment should be used during OLV in an attempt to minimize harmful lung stress and strain. Additional strategies to reduce lung injury include routine volatile anesthesia and efforts to minimize OLV duration and hyperoxia.

Effects of early and late pneumothorax drainage on the development of pulmonary oedema

We analyzed the effects of pneumothorax duration and early or late drainage on lung histology and biological markers associated with inflammation, alveolar fluid clearance, and pulmonary oedema formation. Pneumothorax was induced by injecting air into the thorax of anaesthetized rats, which were randomized according to duration of pneumothorax [5 (PTX5) or 30 (PTX30)min] and further divided to be drained (D) or not (ND). ND rats were euthanized at 5 and 30min. In D groups, pneumothorax was drained and rats breathed spontaneously for 30min. PTX30-ND, compared to PTX5-ND, showed higher alveolar collapse and oedema, type III procollagen, caspase-3, epithelial sodium channel-α, and aquaporin (AQP)-1 mRNA expression, and epithelial and endothelial damage, with reduced cystic fibrosis transmembrane conductance regulator (CFTR) and AQP-3 expression. PTX5-D, compared to PTX30-D, showed less alveolar hyperinflation, oedema, and alveolar-capillary damage, with reduced interleukin-6, caspase-3, AQP-5, and Na,K-ATPase-α and -β expression, and increased CFTR expression. In conclusion, longer duration pneumothorax exacerbated lung damage, oedema, and inflammation.

Reexpansion pulmonary edema: review of pediatric cases

Reexpansion pulmonary edema (RPE) is an increased permeability pulmonary edema that usually occurs in the reexpanded lung after several days of lung collapse. This condition is recognized to occur more frequently in patients under the age of 40 years, but there has been no detailed analysis of reported pediatric cases of RPE to date. For this review, PubMed literature searches were performed using the following terms: 're(-)expansion pulmonary (o)edema' AND ('child' OR 'children' OR 'infant' OR 'boy' OR 'girl' OR 'adolescent'). The 22 pediatric cases of RPE identified were included in this review. RPE was reported in almost the entire pediatric age range, and as in adult cases, the severity ranged from subclinical to lethal. No specific treatment for RPE was identified, and treatment was administered according to the clinical features of each patient. Of the 22 reported cases, 10 occurred during the perioperative period, but were not related to any specific surgical procedures or anesthetic techniques, or to the duration of lung collapse. Pediatric anesthesiologists should be aware that pediatric RPE can occur after reexpansion of any collapsed lung and that some invasive therapies can be useful in severe cases.

From "awake" to "monitored anesthesia care" thoracic surgery: A 15 year evolution

Although general anesthesia still represents the standard when performing thoracic surgery, the interest toward alternative methods is increasing. These have evolved from the employ of just local or regional analgesia techniques in completely alert patients (awake thoracic surgery), to more complex protocols entailing conscious sedation and spontaneous ventilation. The main rationale of these methods is to prevent serious complications related to general anesthesia and selective ventilation, such as tracheobronchial injury, acute lung injury, and cardiovascular events. Trends toward shorter hospitalization and reduced overall costs have also been indicated in preliminary reports. Monitored anesthesia care in thoracic surgery can be successfully employed to manage diverse oncologic conditions, such as malignant pleural effusion, peripheral lung nodules, and mediastinal tumors. Main non-oncologic indications include pneumothorax, emphysema, pleural infections, and interstitial lung disease. Furthermore, as the familiarity with this surgical practice has increased, major operations are now being performed this way. Despite the absence of randomized controlled trials, there is preliminary evidence that monitored anesthesia care protocols in thoracic surgery may be beneficial in high-risk patients, with non-inferior efficacy when compared to standard operations under general anesthesia. Monitored anesthesia care in thoracic surgery should enter the armamentarium of modern thoracic surgeons, and adequate training should be scheduled in accredited residency programs.

Thoracoscopic esophagectomy using prone positioning

Thoracotomic esophagectomy followed by cervical and abdominal procedures has been conventionally performed as the best curable operative procedure for treating invasive thoracic esophageal carcinoma. Despite improvements in the survival rate, the procedure is associated with significant operative morbidity and mortality rates due to the extreme invasiveness of an extensive dissection of the lymph nodes. Minimally invasive esophagectomy (MIE) was developed to reduce surgical invasiveness. Recently, the use of thoracoscopic esophagectomy performed in the prone position has stimulated new interest in minimally invasive approaches. However, the advantages and disadvantages of this technique are not well known. In this review, the literature to date, including series and comparative studies of minimally invasive esophagectomy performed in the prone position, is summarized, and the various lessons learned and controversies surrounding this technique are addressed.

Immune response after systematic lymph node dissection in lung cancer surgery: changes of interleukin-6 level in serum, pleural lavage fluid, and lung supernatant in a dog model

BACKGROUND

Systematic nodal dissection (SND) is regarded as a core component of lung cancer surgery. However, there has been a concern on the increased morbidity associated with SND. This study was performed to investigate whether or not SND induces significant immune response.

METHODS

Sixteen dogs were divided into two groups; group 1 (n = 8) underwent thoracotomy only, and group 2 (n = 8) underwent SND after thoracotomy. We compared interleukin-6 (IL-6) levels in serum, pleural lavage fluid and lung supernatant at the time of thoracotomy (T0) and at 2 h(T1) after thoracotomy (group 1) or SND (group 2). Severity of inflammation and IL-6 expression in lung tissue were evaluated in a semi-quantitative manner.

RESULTS

The operative results were comparable. IL-6 was not detected in serum in either group. IL-6 in pleural lavage fluid marginally increased from 4.75 ± 3.74 pg/mL at T0 to 19.75 ± 8.67 pg/mL at T1 in group 1 (P = 0.112), and from 7.75 ± 5.35 pg/mL to 17.72 ± 8.58 pg/mL in group 2 (P = 0.068). IL-6 in lung supernatant increased from 0.36 ± 0.14 pg/mL/mg to 1.15 ± 0.17 pg/mL/mg in group 1 (P = 0.003), and from 0.25 ± 0.08 pg/mL/mg to 0.82 ± 0.17 pg/mL/mg in group 2 (P = 0.001). However, the degree of increase in IL-6 in pleural lavage fluid and lung supernatant were not different between two groups (P = 0.421 and P = 0.448). There was no difference in severity of inflammation and IL-6 expression between groups.

CONCLUSIONS

SND did not increase IL-6 in pleural lavage fluid and lung supernatant. This result suggests that SND could be routinely performed in lung cancer surgery without increasing the significant inflammatory response.

The impact of tidal volume on pulmonary complications following minimally invasive esophagectomy: a randomized and controlled study

BACKGROUND

Minimally invasive esophagectomy (MIE) has been advantageous for lowering pulmonary complications compared with open approaches.(1) However, pulmonary complications remain the most common morbidity after surgical resection of esophageal cancer.(2,3) The aim of this prospective, randomized, controlled, clinical trial was designed to see whether low tidal volume (VT) could further minimize pulmonary complications after MIE.

METHODS

Between June 2011 and July 2012, a total of 101 patients who underwent MIE received left-lung ventilation during thoracoscopic esophagectomy. All patients received left-lung ventilation during thoracoscopic esophagectomy. Patients were randomly assigned to a low VT (5 mL/kg + 5 cm H2O positive end-expiratory pressure) preserved ventilation (PV) group (n = 53) and a conventional VT (8 mL/kg) controlled ventilation (CV) group (n = 48) in the thoracic stage. Alveolar lavage fluid was harvested from the ventilated lung at intubation and at 18 hours after surgery for analysis of interleukin (IL)-1ß, IL-6, and IL-8 levels. Clinical characteristics, including patient demographics, operation features, and changes in oxygenation index, were recorded and analyzed. Pulmonary complications were identified and statistically compared between the 2 groups.

RESULTS

The clinical characteristics and operation features were comparable between the 2 groups. IL-1ß, IL-6, and IL-8 expressions in preoperative alveolar lavage fluid were similar between the 2 groups. Significantly lower IL expressions were observed in the PV group than those in the CV group at 18 hours after MIE (IL-1ß, 25.42 ± 31.01 vs 94.96 ± 118.24 pg/mL; IL-6, 30.86 ± 75.78 vs 92.99 ± 72.90 pg/mL; IL-8, 258.75 ± 188.24 vs 403.95 ± 151.44 pg/mL; all P < .05). The 18-hour postoperative oxygenation index was lower in the CV group than that in the PV group (292.85 ± 28.74 vs 326.35 ± 34.43; P = .046). Pulmonary complications were observed in 18 cases of our series, occurring more frequently on the ventilation side (right, 6 cases; and left, 12 cases). All patients were cured by conservative therapy without severe sequelae. The occurrence of pulmonary complications in the PV group was lower than that in the CV group (9.43% vs 27.08%; P = .021).

CONCLUSIONS

Lung injury due to intraoperative single-lung ventilation may contribute to pulmonary complications after MIE. Low VT ventilation could decrease ventilation-associated lung inflammation, thus minimizing pulmonary complications after MIE. Further studies, based on a larger volume of populations, are required to confirm these findings.

Acute lung injury in thoracic surgery

PURPOSE OF REVIEW

This review will analyze the risk factors of acute lung injury (ALI) in patients undergoing thoracic surgery. Evidence for the occurrence of lung injury following mechanical ventilation and one-lung ventilation (OLV) and the strategies to avoid it will also be discussed.

RECENT FINDINGS

Post-thoracotomy ALI has become one of the leading causes of operative death. The pathogenesis of ALI implicates a multiple-hit sequence of various triggering factors (e.g. preoperative conditions, surgery-induced inflammation, ventilator-induced injury, fluid overload, and transfusion). Conventional ventilation during OLV is performed with high tidal volumes equal to those being used in two-lung ventilation, high FiO(2), and without positive end-expiratory pressure. This practice was originally recommended to improve oxygenation and decrease shunt fraction during OLV. However, a number of recent studies using experimental models or human patients have shown low tidal volumes to be associated with a decrease in inflammatory mediators and a reduction in pulmonary postoperative complications. However, the application of such protective strategies could be harmful if not still properly used.

SUMMARY

The goal of ventilation is to minimize lung trauma by avoiding overdistension and repetitive alveolar collapse, while providing adequate oxygenation. Protective ventilation is not simply synonymous of low tidal volume ventilation, but it also involves positive end-expiratory pressure, lower FiO(2), recruitment maneuvers, and lower ventilatory pressures.

Volatile anesthetic preconditioning attenuated sepsis induced lung inflammation

BACKGROUND

This study aimed to evaluate the differential protective effects of isoflurane or sevoflurane on lung inflammation in a rat model of cecal ligation and puncture (CLP) induced sepsis.

METHODS

Seventy-two rats were assigned to control, sevoflurane, or isoflurane groups. At 2 and 4 h, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), nitrate/nitrate levels (NO), total antioxidant capacity (TAC), and intercellular cell adhesion molecule-1 (ICAM-1) were determined. At 12 and 24 h, malondialdehyde (MDA), myeloperoxidase (MPO), and histologic changes were evaluated. Survival was monitored for 7 d after CLP.

RESULTS

Sevoflurane (75%) and isoflurane (63%) significantly improved survival rate compared with control rats (38%). When sevoflurane and isoflurane groups were compared, sevoflurane pretreatment showed significant decrease in NO at 2 h [1045 (803-1274)/1570 (1174-2239) and 4 h [817 (499-1171)/1493 (794-2080)]; increase in TAC at 4 h [580.0 (387-751)/320 (239-512)]; decrease in MDA at 12 h [2.5 (1.1-4.2)/5.4 (4-73)] and 24 h [10.8 (6.0-14.0)/15.9 (9-28)]; and decrease in MPO at 24 h [145.8 (81-260)/232 (148-346)]. The difference in the ICAM-1 expression of the isoflurane and sevoflurane groups was not significant at both measurement times. The architectural integrity of the alveoli was preserved in all the groups. The injury scores of the three groups at 12 and 24 h did not show any significant difference.

CONCLUSIONS

Both sevoflurane and isoflurane attenuated inflammatory response, lipid peroxidation, and oxidative stress. Furthermore, sevoflurane was more effective in modulating sepsis induced inflammatory response at the chosen concentration in sepsis model.

Thoracoscopic esophagectomy in the prone position

BACKGROUND

Minimally invasive esophageal surgery has arisen in an attempt to reduce the significant complications associated with esophagectomy. Despite proposed technical and physiological advantages, the prone position technique has not been widely adopted. This article reviews the current status of prone thoracoscopic esophagectomy.

METHODS

A systematic literature search was performed to identify all published clinical studies related to prone esophagectomy. Medline, EMBASE and Google Scholar were searched using the keywords "prone," "thoracoscopic," and "esophagectomy" to identify articles published between January 1994 and September 2010. A critical review of these studies is given, and where appropriate the technique is compared to the more traditional minimally invasive technique utilising the left lateral decubitus position.

RESULTS

Twelve articles reporting the outcomes following prone thoracoscopic oesophagectomy were tabulated. These studies were all non-randomised single-centre prospective or retrospective studies of which four compared the technique to traditional minimally invasive surgery. Although prone esophagectomy is demonstrated as being both feasible and safe, there is no convincing evidence that it is superior to other forms of esophageal surgery. Most authors comment that the prone position is associated with superior surgical ergonomics and theoretically offers a number of physiological benefits.

CONCLUSION

The ideal approach within minimally invasive esophageal surgery continues to be a subject of debate since no single method has produced outstanding results. Further clinical studies are required to see whether ergonomic advantages of the prone position can be translated into improved patient outcomes.

Regional Lung Chemotherapy Techniques

Selective delivery of chemotherapy to an affected organ or region of the body promises improved drug efficacy for the targeted area while minimizing the systemic exposure and toxicity. Several intravascular surgical techniques to achieve targeted regional lung chemotherapy have been developed. Investigations have been carried out to determine the feasibility, safety, and efficacy of these techniques in the primary or adjuvant setting with the intent to palliate or cure. This overview describes the history, rationale, technical aspects, and clinical experience of four regional lung chemotherapy techniques delivered by vascular manipulations including bronchial artery infusion, pulmonary artery chemoembolization, isolated lung perfusion, and lung suffusion.

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

BACKGROUND

Protective ventilation strategy has been shown to reduce ventilator-induced lung injury in patients with ARDS. In this study, we questioned whether protective ventilatory settings would attenuate lung impairment during one-lung ventilation (OLV) compared with conventional ventilation in patients undergoing lung resection surgery.

METHODS

One hundred patients with American Society of Anesthesiology physical status 1 to 2 who were scheduled for an elective lobectomy were enrolled in the study. During OLV, two different ventilation strategies were compared. The conventional strategy (CV group, n=50) consisted of FIO2 1.0, tidal volume (Vt) 10 mL/kg, zero end-expiratory pressure, and volume-controlled ventilation, whereas the protective strategy (PV group, n=50) consisted of FIO2 0.5, Vt 6 mL/kg, positive end-expiratory pressure 5 cm H2O, and pressure-controlled ventilation. The composite primary end point included PaO2/FIO2<300 mm Hg and/or the presence of newly developed lung lesions (lung infiltration and atelectasis) within 72 h of the operation. To monitor safety during OLV, oxygen saturation by pulse oximeter (SpO2), PaCO2, and peak inspiratory pressure (PIP) were repeatedly measured.

RESULTS

During OLV, although 58% of the PV group needed elevated FIO2 to maintain an SpO2>95%, PIP was significantly lower than in the CV group, whereas the mean PaCO2 values remained at 35 to 40 mm Hg in both groups. Importantly, in the PV group, the incidence of the primary end point of pulmonary dysfunction was significantly lower than in the CV group (incidence of PaO2/FIO2<300 mm Hg, lung infiltration, or atelectasis: 4% vs 22%, P<.05).

CONCLUSION

Compared with the traditional large Vt and volume-controlled ventilation, the application of small Vt and PEEP through pressure-controlled ventilation was associated with a lower incidence of postoperative lung dysfunction and satisfactory gas exchange.

TRIAL REGISTRY

Australian New Zealand Clinical Trials Registry; No.: ACTRN12609000861257; URL: www.anzctr.org.au.

Robot-assisted thoracoscopic oesophagectomy for cancer

BACKGROUND

Thoracoscopic oesophagectomy was introduced to reduce the morbidity of transthoracic oesophagectomy. The aim was to assess the short- and mid-term results of robot-assisted thoracoscopic oesophagectomy for oesophageal cancer.

METHODS

Between October 2003 and May 2007, 47 patients with resectable oesophageal cancer underwent robot-assisted thoracoscopic oesophagectomy. Clinical data were collected prospectively.

RESULTS

Conversion to thoracotomy was necessary in seven patients. Median operating time was 450 min and median blood loss 625 ml. Median postoperative ventilation time was 1 day, intensive care stay 3 days and hospital stay 18 days. Twenty-one of 47 patients had pulmonary complications. Three patients died in hospital. A median of 29 (range 8-68) lymph nodes was dissected and R0 resection was achieved in 36 patients. Twenty-three patients had stage IVa disease. After a median follow-up of 35 months, median disease-free survival was 15 (95 per cent confidence interval 12 to 18) months.

CONCLUSION

Robot-assisted thoracoscopic oesophagectomy was oncologically acceptable. Operating time, blood loss and pulmonary complications might decrease with further experience.

Delayed onset of contralateral pulmonary edema following reexpansion pulmonary edema of a collapsed lung after video-assisted thoracoscopic surgery

This case report describes a 61-year-old man who developed reexpansion pulmonary edema (RPE) of the collapsed left lung after video-assisted thoracoscopic surgery because of left thoracic empyema, complicated with secondary contralateral pulmonary edema later. The left lung was gently reexpanded after surgery under one-lung ventilation anesthesia for 2.5 hours. The patient developed RPE of the left lung immediately after surgery, and required mechanical ventilation with positive end-expiratory pressure support. RPE was resolved within 24 hours. Nevertheless, delayed onset of contralateral pulmonary edema manifested on chest radiography 4 days later without clinical symptoms such as tachypnea or dyspnea. There was no evidence of pulmonary infection, fluid overload, postoperative renal insufficiency or cardiogenic onslaught. Late manifestation of contralateral pulmonary edema in the wake of previous left-sided RPE was suspected from exclusion of possible culprits. Response to steroid therapy made inflammation-related pulmonary edema a likely diagnosis. This case demonstrates that delayed contralateral pulmonary edema with only radiographic evidence can emerge 4 days after resolution of RPE of a collapsed lung. Methods to prevent RPE and management of one-lung ventilation are described.

Acute lung injury and outcomes after thoracic surgery

PURPOSE OF REVIEW

The present review evaluates the evidence available in the literature tracking perioperative mortality and morbidity as well as the pathogenesis and management of acute lung injury (ALI) in patients undergoing thoracotomy.

RECENT FINDINGS

Over the last decade, despite increasing age and comorbid conditions, the operative mortality has remained unchanged for patients undergoing lung resection, whereas procedure-related complications have declined. Better clinical outcomes are achieved in high-volume hospitals and when procedures are performed by a thoracic surgeon. Postthoracotomy ALI has become the leading cause of operative death, its incidence has remained stable (2-5%) and earlier diagnosis can be made by assessing the extravascular lung water volume with the single-indicator dilution technique. The pathogenesis of ALI implicates a multiple-hit sequence of various triggering factors (e.g. oxidative stress and surgical-induced inflammation) in addition to injurious ventilatory settings and genetic predisposition.

SUMMARY

Knowledge of the perioperative risk factors of major complications and understanding of the mechanisms of postthoracotomy ALI enable anesthesiologists to implement 'protective' lung strategies including the use of low tidal volume (VT) with recruitment maneuvers, a goal-directed fluid approach and prophylactic treatment with inhaled beta2-adrenergic agonists.

Histochemical Alterations in One Lung Ventilation

BACKGROUND

One lung ventilation is a commonly performed surgical procedure. Although there have been several reports showing that one-lung ventilation can cause pathophysiological alterations such as pulmonary hypoxic vasoconstriction and intrapulmonary shunting, there have been virtually no reports on the effects of one-lung ventilation on lung histology.

MATERIALS AND METHODS

Yorkshire pigs (11-17 kg) were anesthetized, a tracheotomy performed and a tracheal tube inserted. The chest was opened and one lung ventilation (OLV), was induced by clamping of the right main bronchus. OLV was continued for 60 min before the clamp was removed and two lung ventilation (TLV) started. TLV was continued for 30 to 60 min. Blood and lung biopsies were taken immediately before OLV, 30 min and 60 min of OLV and after restoration of TLV.

RESULTS

Histological analyses revealed that the non-ventilated lung was totally collapsed during OLV. On reventilation, there was clear evidence of vascular congestion and alveolar wall thickening at 30 min after TLV. At 60 min of TLV, there was still vascular congestion. Serum nitrite levels (as an index of nitric oxide production) showed steady decline over the course of the experimental period, reaching a significantly low level on reventilation (compared with baseline levels before OLV). Lung MPO activity (marker of neutrophil sequestration) and serum TNFalpha levels were not raised during the entire experimental period.

CONCLUSIONS

These results suggest that there was lung vascular injury after OLV, which was associated with reduced levels of nitric oxide production and not associated with an inflammatory response.

Local and systemic impacts of pleural oxygen exposure in thoracotomy

The pleural cavity is normally in a state of negative pressure and low oxygen tension. It is exposed to the atmosphere during thoracic surgery. However, no reports of pathophysiological investigation of the effects of pleural oxygen exposure involved in thoracotomy are available. In this study, the effects of pleural oxygen exposure on systemic and pleural inflammation were investigated. Male Wistar rats (9 weeks old) were placed on mechanical ventilation and underwent thoracotomy with lipopolysaccharide (LPS) administration, which simulates latent inflammatory condition. The pleural cavity was exposed to nitrogen (N(2) thoracotomy group), air (20% oxygen, air thoracotomy group), or 100% oxygen (O(2) thoracotomy group) under mechanical ventilation for 2 h. Animals were sacrificed 2 h or 8 h after LPS administration, and inflammatory indices (plasma tumor necrosis factor-alpha and interleukin-6, histology) were examined. For examination of inflammatory mediators, pleural effusion was added to cultured RAW264 cells, a murine macrophage cell line, and tumor necrosis factor-alpha levels in supernatant were measured. The capacity of pleural superoxide generation was investigated without LPS administration. Results showed increases in plasma interleukin-6 concentration and lung injury in the air and O(2) thoracotomy groups. Pleural oxygen exposure stimulated pleural superoxide generation, and increased pleural 4-hydroxy-2-nonenal and lung lipid peroxide concentrations. Tumor necrosis factor-alpha levels in cell culture supernatants were increased by the addition of pleural effusion from the air and O(2) thoracotomy groups. In conclusion, pleural oxygen exposure induced pleural oxidative injury and aggravated latent systemic inflammatory response.

Lung injury after thoracic surgery and one-lung ventilation

PURPOSE OF REVIEW

An update is provided for anaesthetists, on recent work investigating the incidence and cause of lung injury following thoracic surgery. Pulmonary damage is also discussed in relation to the management of one-lung ventilation.

RECENT FINDINGS

The extent of recent original literature on lung injury, following thoracic surgery, is limited for the review period (2004-2005). Increasing evidence that pulmonary oxidative stress and an increase in proinflammatory cytokines are significant contributors to lung injury following thoracic surgery, however, exists. This is particularly the case in patients with lung or oesophageal carcinoma. Animal experiments confirm the above and also indicate that anaesthetic agents may offer some protection against the ischaemia-reperfusion injury sustained as a result of one-lung ventilation.

SUMMARY

Pulmonary damage in the form of acute lung injury and adult respiratory distress syndrome is a major cause of morbidity and mortality after thoracic surgery. An understanding of the pathogenesis of lung damage, following thoracic surgery, may enable anaesthetists to modify this process and decrease the incidence and severity of the problem.