Acute lung injury following lung resection: is one lung anaesthesia to blame?

The Theoretical Basis for Using Apnoeic Oxygenation via the Non-ventilated Lung during One-lung Ventilation to Delay the Onset of Arterial Hypoxaemia

At the time one-lung ventilation is initiated, nitrogen from the atmosphere may enter the non-ventilated lung via a double-lumen tube connector that has been left open to air, even momentarily. Ongoing oxygen uptake from the non-ventilated lung raises the partial pressure of nitrogen. This should lead to activation of hypoxic pulmonary vasoconstriction and a reduction in intra-pulmonary shunting. However, in spite of this, some patients still become hypoxaemic. In such cases, it may be advantageous to have excluded nitrogen from the non-ventilated lung by connecting it to an oxygen source at ambient pressure. Ongoing apnoeic oxygenation, while the airways are patent, and as the lung collapses, should delay the onset of arterial desaturation. In this paper we review the theoretical basis for apnoeic oxygenation during one-lung ventilation, and in particular on oxygen uptake by the non-ventilated lung prior to and during its subsequent collapse.

Antiinflammatory effect of sevoflurane in open lung surgery with one-lung ventilation

Aim

To prospectively assess the antiinflammatory effect of volatile anesthetic sevoflurane in patients undergoing open lung surgery with one lung ventilation (OLV).

Methods

This prospective, randomized study included 40 patients undergoing thoracic surgery with OLV (NCT02188407). The patients were randomly allocated into two equal groups that received either propofol or sevoflurane. Four patients were excluded from the study because after surgery they received blood transfusion or non-steroid antiinflammatory drugs. Inflammatory mediators (interleukins 6, 8, and 10, C-reactive protein [CRP], and procalcitonin) were measured perioperatively. The infiltration of the nonoperated lung was assessed on chest x-rays and the oxygenation index was calculated. The major postoperative complications were counted.

Results

Interleukin 6 levels were significantly higher in propofol than in sevoflurane group (P = 0.014). Preoperative CRP levels did not differ between the groups (P = 0.351) and in all patients they were lower than 20 mg/L, but postoperative CRP was significantly higher in propofol group (31 ± 6 vs 15 ± 7 ng/L; P = 0.035); Pre- and postoperative procalcitonin was within the reference range (<0.04 µg/L) in both groups. The oxygenation index was significantly lower in propofol group (339 ± 139 vs 465 ± 140; P = 0.021). There was no significant difference between the groups in lung infiltrates (P = 0.5849). The number of postoperative adverse events was higher in propofol group, but the difference was not-significant (5 vs 1; P = 0.115).

Conclusion

The study suggests an antiinflammatory effect of sevoflurane in patients undergoing thoracotomy with OLV.

Endothelial progenitor cell mobilization by preoperative exercise: a bone marrow response associated with postoperative outcome

BACKGROUND

Preoperative anaemia is associated with increased morbidity in patients undergoing major surgery. Whether erythrocytes are the only bone-marrow-derived cell lineage that associates with increased surgical complications is unknown. This prospective observational trial studied the mobilization of endothelial progenitor cells (EPCs) in response to exercise in association with postoperative complications.

METHODS

After IRB approval, 60 subjects undergoing major thoracic surgery were exercised to exhaustion (peak V̇(O₂)). Peripheral blood collected before and after peak exercise was quantified for EPC lineages by fluorescence-activated cell sorter analysis. Complication analysis was based on the Clavien-Dindo classification.

RESULTS

Exhaustive exercise increased EPC [CD45-133+34+ cells=150 (0.00-5230) to 220 (0.00-1270) cells μl(-1); median change (range)=20 (-4,180-860) cells μl(-1); P=0.03] but not mature endothelial cell (EC) subpopulations. Pre-exercise levels [odds ratio (OR)=0.86, 95% confidence interval (CI): 0.37-2.00, P=0.72), change after exercise as a continuous variable (OR=0.95, 95% CI: 0.41-2.22, P=0.91) and a positive response after exercise (change >0 cells μl(-1); OR=0.41, 95% CI: 0.13-1.28, P=0.12) were not statistically significantly associated with the incidence of postoperative complications. Post-hoc receiver operating characteristic curve analyses revealed that subjects with a CD45-133+34+ increase ≥60 cells μl(-1) in response to exercise suffered fewer postoperative complications [86% sensitivity, 48% specificity and AUC=0.67 (95% CI: 0.52-0.81)].

CONCLUSIONS

Preoperative exercise induces EPC into the peripheral circulation. Subjects with a poor EPC response had a pre-existing propensity for postoperative complications. This warrants further research into the role of bone marrow function as a critical component to endothelial repair mechanisms.

CLINICAL TRIAL REGISTRATION

IRB 2003-0434 (University of Texas M.D. Anderson Cancer Center, Houston, TX, USA).

Surfactant administration prior to one lung ventilation: physiological and inflammatory correlates in a piglet model

OBJECTIVES

To test the hypothesis that surfactant, when given prophylactically during one lung ventilation (OLV), improves physiological stability and reduces inflammation.

METHODS

Prospective controlled animal study. After 30 min of mechanical ventilation, surfactant was administered to the left lung of the treatment group. Right lung mechanical ventilation continued for 3 hr, after which the left lung was unblocked. Bilateral mechanical ventilation was continued for 30 min thereafter. Physiological parameters and biomarkers of inflammation in plasma, lung tissue homogenates, and bronchoalveolar lavage (BAL) were measured.

MEASUREMENTS AND MAIN RESULTS

Oxygenation improved in the surfactant group, reaching statistical significance at 3 hr of OLV and again after 30 min of bilateral mechanical ventilation following the OLV. Plasma levels of interleukin (IL)-1 β, IL-6, and tumor necrosis factor (TNF)-α showed a trend for reduction. The lung homogenates from the ventilated lungs had significantly lower levels of IL-1 β (P < 0.01) and IL-6 (P < 0.01). The BAL specimen showed an overall reduction in the cytokine levels; IL-1 β was significantly lower in the ventilated lungs (P < 0.01).

CONCLUSIONS

Surfactant administration improves oxygenation and decreases inflammation, as evidenced by a decrease in several inflammatory cytokines both in the plasma and lungs of a piglet model of OLV.

Interleukin-10 delivery via mesenchymal stem cells: a novel gene therapy approach to prevent lung ischemia-reperfusion injury

Ischemia-reperfusion (IR) injury is an important cause of primary graft failure in lung transplantation. In this study, viral interleukin-10 (vIL-10)-engineered mesenchymal stem cells (MSCs) were tested for their ability to prevent lung IR injury. Bone marrow-derived MSCs were transduced with rvIL-10-retrovirus. After 120 min of warm left lung ischemia, rats received approximately 15 x 10(6) vIL-10-engineered MSCs (MSC-vIL-10), empty vector-engineered MSCs (MSC-vec), or saline intravenously. Mean blood oxygenation (PaO(2)/FiO(2) ratio, mmHg) was measured at 4 hr, 24 hr, 72 hr, and 7 days. As early as 4 hr post-IR injury with MSC-vIL-10 treatment, blood oxygenation was significantly (p < 0.05) improved (319 +/- 94; n = 7) compared with untreated (saline) controls (63 +/- 19; n = 6). At 24 hr post-IR injury, in the MSC-vIL-10-treated group there was a further increase in blood oxygenation (353 +/- 105; n = 10) compared with the MSC-vec group (138 +/- 86; n = 9) and saline group (87 +/- 39; n = 10). By 72 hr, oxygenation reached normal (475 +/- 55; n = 9) in the MSC-vIL-10-treated group but not in the saline-treated and MSC-vec-treated groups. At 4 hr after IR injury, lungs with MSC-vIL10 treatment had a lower (p < 0.05) injury score (0.9 +/- 0.4) compared with lungs of the untreated (saline) group (2.5 +/- 1.4) or MSC-vec-treated group (2 +/- 0.4). Lung microvascular permeability and wet-to-dry weight ratios were markedly lower in the MSC-vIL10 group compared with untreated (saline) controls. ISOL (in situ oligonucleotide ligation for DNA fragmentation detection) and caspase-3 staining demonstrated significantly (p < 0.05) fewer apoptotic cells in MSC-vIL10-treated lungs. Animals that received MSC-vIL10 therapy had fewer (p < 0.05) CD4(+) and CD8(+) T cells in bronchoalveolar lavage fluid compared with untreated control animals. A therapeutic strategy using vIL-10-engineered MSCs to prevent IR injury in lung transplantation seems promising.

Low dose methylprednisolone prophylaxis to reduce inflammation during one-lung ventilation

BACKGROUND

The specific aim of this study was to examine the efficacy of a low dose of methylprednisolone in minimizing inflammatory response in juvenile piglets when given 45-60 min prior to onset of one-lung ventilation.

METHODS

Twenty piglets aged 3 weeks were assigned to either the control group (n = 10) or methylprednisolone group (n = 10). The animals were anesthetized and after 30 min of ventilation, they had their left lung blocked. Ventilation was continued via right lung for 3 h. The left lung was then unblocked. Following another 30 min of bilateral ventilation, the animals were euthanized and both lungs were harvested. The methylprednisolone group had a single dose (2 mg x kg(-1)) of methylprednisolone given i.v. 45-60 min prior to onset of one-lung ventilation. Physiological parameters (PaO2, resistance, and compliance) and markers of inflammation (tumor necrosis factor [TNF]-alpha, interleukin [IL]-1beta, IL-6, and IL-8) were measured at baseline and every 30 min thereafter. Lung tissue homogenates from both collapsed and ventilated lungs were analyzed for TNF-alpha, IL-1beta, IL-6, and IL-8.

RESULTS

The methylprednisolone group had higher partial pressure of oxygen (P = 0.01), lower plasma levels of TNF-alpha (P = 0.03) and IL-6 (P = 0.001) when compared with control group. Lung tissue homogenate in the methylprednisolone group had lower levels of TNF-alpha (P < 0.05), IL-1beta (P < 0.05), and IL-8 (P < 0.05) in both the collapsed and the ventilated lungs.

CONCLUSIONS

In a piglet model of one-lung ventilation, use of prophylactic methylprednisolone prior to collapse of the lung improves lung function and decreases systemic pro-inflammatory response. In addition, in the piglets who received methylprednisolone, there were reduced levels of inflammatory mediators in both the collapsed and ventilated lungs.

Oxygen toxicity during one-lung ventilation: is it time to re-evaluate our practice?

Lung cancer remains one of the leading causes of cancer-related mortality. Surgical resection remains the mainstay of non-small cell lung cancer therapy, but an increasing number of patients receive preoperative adjuvant chemotherapy that may predispose these patients to unique organ toxicities. This chemotherapy, along with exposure to high oxygen concentrations, may combine to increase the risk of reactive oxygen species-mediated lung injury. Continued efforts are needed to improve overall outcome in these patients, including a reevaluation of our management of oxygen therapy.

One-lung ventilation: For how long?

OBJECTIVE

Lung injury induced by one-lung ventilation is rare, but it is a condition that may result in high mortality. This study evaluates the effects of one-lung ventilation and occlusion time on collapsed and contralateral lungs.

METHODS

Sprague-Dawley rats were allocated randomly into 7 groups consisting of 6 animals each: sham; O1, 1 hour of occlusion/2 hours of re-expansion; C1, 3 hours of mechanical ventilation control; O2, 2 hours of occlusion/2 hours of re-expansion; C2, 4 hours of mechanical ventilation control; O3, 3 hours of occlusion/2 hours of re-expansion; and C3, 5 hours of mechanical ventilation control groups. In the occlusion groups, the left lung was collapsed by bronchial occlusion. Malondialdehyde activity was determined in the blood, and myeloperoxidase and malondialdehyde activity was determined in the collapsed and contralateral lungs. Lung tissues were also examined histopathologically.

RESULTS

Malondialdehyde and myeloperoxidase levels rose as occlusion duration increased. This increase was greater in the occlusion groups than that in their own control groups. Increases were significant in the O2 compared with the O1 groups (P < .005). Histologically, tissue damage increased as occlusion time rose injury in collapsed and contralateral lungs. Injury was greater in the occlusion groups than injury in their own control groups (P < .005).

CONCLUSIONS

Our findings show that biochemical and histopathologic injury occur in collapsed and contralateral lungs in one-lung ventilation, and this injury increases as occlusion time rises. We believe that occlusion and occlusion time-related injury should be borne in mind in the clinic under conditions requiring the application of one-lung ventilation.

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.

Acute lung injury and acute respiratory distress syndrome after pulmonary resection

The occurrence of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) after thoracic surgery are perplexing and persistent problems. Variously described as postpneumonectomy pulmonary edema, noncardiogenic pulmonary edema, and postlung resection pulmonary edema, ALI and ARDS may be considered a single entity, with ALI being the less severe form of ARDS. It is characterized by the acute onset of hypoxemia with radiographic infiltrates consistent with pulmonary edema, without elevations in the pulmonary capillary wedge pressure. Although this syndrome does not occur frequently and is usually without identifiable cause, the mortality is high. However, the phenomenon has not been rigorously studied owing to the low incidence, with primarily retrospective case series reported. Thus, the nomenclature, risks, and pathogenesis are not well defined. Interest in this syndrome has recently been renewed as the rate of other perioperative complications has declined. ALI/ARDS is reviewed with a focus on potential etiologies and the spectrum of available interventions.

A case of unilateral re-expansion pulmonary oedema successfully treated with non-invasive continuous positive airway pressure

Unilateral re-expansion pulmonary oedema is a rare threatening complication of the treatment of lung atelectasis, pleural effusion or pneumothorax, the pathogenesis of which is not completely known. The clinical picture varies considerably from asymptomatic radiological findings to dramatic respiratory failure with circulatory shock. There are few literature reports of the treatment of re-expansion pulmonary oedema with non-invasive continuous positive airway pressure. We present the case of a 75-year-old man who presented in our emergency room with a large left-sided spontaneous pneumothorax and developed severe respiratory failure and circulatory collapse after drainage via a chest tube. The diagnosis of unilateral re-expansion pulmonary oedema was made and he was successfully treated with non-invasive continuous positive airway pressure. Literature data about the aetiological and pathogenetic factors of the condition are also considered.

Risk Factors for Acute Lung Injury After Thoracic Surgery for Lung Cancer

Acute lung injury (ALI) may complicate thoracic surgery and is a major contributor to postoperative mortality. We analyzed risk factors for ALI in a cohort of 879 consecutive patients who underwent pulmonary resections for non-small cell lung carcinoma. Clinical, anesthetic, surgical, radiological, biochemical, and histopathologic data were prospectively collected. The total incidence of ALI was 4.2% (n = 37). In 10 cases, intercurrent complications (bronchopneumonia, n = 5; bronchopulmonary fistula, n = 2; gastric aspiration, n = 2; thromboembolism, n = 1) triggered the onset of ALI 3 to 12 days after surgery, and this was associated with a 60% mortality rate (secondary ALI). In the remaining 27 patients, no clinical adverse event preceded the development of ALI-0 to 3 days after surgery-that was associated with a 26% mortality rate (primary ALI). Four independent risk factors for primary ALI were identified: high intraoperative ventilatory pressure index (odds ratio, 3.5; 95% confidence interval, 1.7-8.4), excessive fluid infusion (odds ratio, 2.9; 95% confidence interval, 1.9-7.4), pneumonectomy (odds ratio, 2.8; 95% confidence interval, 1.4-6.3), and preoperative alcohol abuse (odds ratio, 1.9; 95% confidence interval, 1.1-4.6). In conclusion, we describe two clinical forms of post-thoracotomy ALI: 1). delayed-onset ALI triggered by intercurrent complications and 2). an early form of ALI amenable to risk-reducing strategies, including preoperative alcohol abstinence, lung-protective ventilatory modes, and limited fluid intake.

IMPLICATIONS

In an observational study including all patients undergoing lung surgery, we describe two clinical forms of acute lung injury (ALI): a delayed-onset form triggered by intercurrent complications and an early form associated with preoperative alcohol consumption, pneumonectomy, high intraoperative pressure index, and excessive fluid intake over the first 24 h.

The Thoracic Surgical Patient: Initial Postoperative Care

Thoracic surgery patients require complex perioperative care. Accurate preoperative screening of pulmonary conditions can only partially predict the requirement of postoperative mechanical ventilation. In general, extensive lung resections are associated with significant gas exchange abnormalities. In this group of patients, a mechanical ventilation strategy protective from barotrauma and volutrauma and a conservative use of intraoperative and postoperative fluid limit the inevitable increase of extravascular lung water and gas exchange impairment. A wise use of pulmonary vasodilatatory and bronchodilating drugs and airway manipulation including suctioning and bronchoscopy can also significantly affect postoperative respiratory dysfunction and hospital stay. A number of acute postoperative complications have been described specifically related to the type of surgery or pleural space suctioning devices. The role of the intensivist is to maintain a low index of suspicion for such complications, when acute hemodynamic or pulmonary deterioration occurs and be prepared to immediately correct them or alert the thoracic surgeon. In general, when these roles are observed, thoracic surgery can be safely performed with a low perioperative mortality.

Pathophysiology of one-lung ventilation

The management of some problematic patients having thoracic surgery is among the most difficult challenges for the anesthesiologist. Increasingly complex operations are performed on seriously compromised patients because of the development of new surgical techniques and the anesthesiologists' awareness of surgical needs and requirements to provide a satisfactory and safe surgical field. In order to facilitate thoracic surgery, the single most important and valuable anesthetic technique used actually is one-lung ventilation. This article reviews the complex pathopysiology of one-lung ventilation.

Acute lung injury and acute respiratory distress syndrome after pulmonary resection

BACKGROUND

In this study we investigate the frequency and mortality of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) after pulmonary resection.

METHODS

Patients that underwent pulmonary resection at the Royal Brompton Hospital between 1991 and 1997 were included. The case notes of all patients developing postoperative complications were retrospectively reviewed.

RESULTS

The overall combined frequency of ALI and ARDS was 3.9%. The frequency was higher in patients over 60 years of age, males and those undergoing resection for lung cancer. ALI/ARDS caused 72.5% of the total mortality after resection in this series.

CONCLUSIONS

In our experience ALI and ARDS are major causes of mortality after lung resection.

Massive contralateral pneumonia following thoracotomy for lung resection

Separation of the lungs with a double-lumen endobronchial tube facilitates the surgical approach and protects the bronchial system from contamination by pus or blood from the operated lung. We report a case of a 49-year-old man who suffered a gram-negative pneumonia requiring mechanical ventilatory support and prolonged hospitalization after pulmonary resection. Contamination of the ventilated-dependent lung was documented intraoperatively. Current information on postoperative infectious complications and preventive measures are discussed.